ZBORNIK REFERATOV XXIX. SIMPOZIJA...ZBORNIK REFERATOV XXIX. SIMPOZIJ O AKTUALNIH BOLEZNIH MALIH ŽIVALI Portorož, 8. in 9. april 2016 5 Generalni pokrovitelj Iris mednarodna trgovina

Portorož, 8. in 9. april 2016

ZBORNIK REFERATOV

Univerza v LjubljaniVeterinarska fakulteta

XXIX. SIMPOZIJAo aktualnih boleznih malih `ivali

ZBORNIK REFERATOV

XXIX. SIMPOZIJA O AKTUALNIH

BOLEZNIH MALIH ŽIVALI

Portorož, 2016 http://www.zdruzenje-szvmz.si/

XXIX. SIMPOZIJ O AKTUALNIH BOLEZNIH MALIH ŽIVALI ZBORNIK REFERATOV


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Izdalo: Slovensko združenje veterinarjev za male živali

Oblikovanje:AKTA DESIGNwww.aktadesign.si

270 izvodov

Vsebina

Findji L. Principles of oncologic surgery ........................................................................................ 8

Findji L. Skin reconstruction in oncologic surgery ........................................................................ 11

Nemec A. Tumorji in načela onkološke kirurgije v ustni votlini .................................................... 15

Findji L. Canine and feline soft tissue sarcomas .......................................................................... 18

Findji L. Tumours of the body walls ............................................................................................ 24

Nemec A. Defekti neba .............................................................................................................. 28

Krofič Žel M. Oskrba in klinično spremljanje pacienta s kronično ledvično boleznijo ..................... 38

Kožuh T. Surova prehrana kot del terapije .................................................................................. 42

Tozon N. Kaj moramo vedeti o odkrivanju, zdravljenju in predvsem preprečevanju nekaterih

parazitarnih obolenj .................................................................................................................. 44

Pogorevc E. Ultrazvočna diagnostika malih živali ........................................................................ 46

Nemec A. Halo, veterina? Moj pes si je ravnokar zlomil zob ........................................................ 52

Plavec T. Pozdravljeni, rad bi govoril s kirurgom… Najpogostejša vprašanja in (ne)enostavni

odgovori ................................................................................................................................... 55

Sist B. Perioperative pain management in dogs and cats ............................................................ 66

Tozon N, Lampreht Tratar U, Žnidar K, Serša G, Teissie J, Čemažar M. Elektrokemoterapija –

operativni postopek ................................................................................................................... 67

Butinar J, Rejec A, Benoit J. Resekcije tumorjev v kombinaciji z radioterapijo – multimodalni

pristop k zdravljenju onkoloških pacientov ................................................................................. 67

Plavec T, Rupp S, Kessler M. Zasuk širokega črevesja pri psih in primerjava z zasuki želodca

in mezenterialnega korena ........................................................................................................ 68

Zadravec M, Račnik J, Nemec A, Bahč I. Prehrana malih rastlinojedih sesalcev z boleznimi zob .... 68

Kvapil P, Kastelic M, Gorenšek M. Zlom radiusa in ulne pri zlatoličnem gibonu ............................ 69

Dolenšek T, Gombač M, Švara T. Patohistološka preiskava - kakšne so koristi za veterinarja

praktika? .................................................................................................................................. 69

Hudobivnik A. Uporaba akupunkture za lajšanje bolečin pri pacientu z lumbalno stenozo,

artritisom komolca ter boreliozo ................................................................................................ 69

Kvapil P, Kastelic M, Zadravec M, Gombač M, Švara T, Golob M, Račnik J. Kloacitis pri

bradatih agamah v živalskem vrtu Ljubljana ............................................................................... 70

Praprotnik Borko Š. Kirurška sanacija mastocitoma pri zlati prinašalki ......................................... 70

Trojner G, Kessler M. Torzija pljučnega režnja pri ruskem hrtu ..................................................... 70

Zakošek Pipan M, O’Connor C. Neustrezen spolni razvoj – trisomija X ........................................ 71

ZBORNIK REFERATOV XXIX. SIMPOZIJ O AKTUALNIH BOLEZNIH MALIH ŽIVALI


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Generalni pokrovitelj

Iris mednarodna trgovina d.o.o. Cesta v Gorice 8, 1000 Ljubljana

in partnerji

Elanco

Natures Menu

Zoetis

Posebni pokrovitelji

Krka d.d., Šmarješka cesta 6, 8501 Novo mesto

Richter Pharma AG, Feldgasse 19, 4600 Wels, Austria

Vetconsult Pharma d.o.o., Grebičeva 50, 1000 Ljubljana

Vetpromet, Cesta na Brdo 100, 1000 Ljubljana

Simpozij so omogočili še

e MEDICA, d.o.o., Linhartova 8a, 8250 Brežice

EVG molekularna diagnostika d.o.o., Taborska ulica 8, 2000 Maribor

Farmina in DJ Plus d.o.o., Tovarniška c. 15, 3312 Prebold

Genera SI d.o.o., Parmova ulica 53, 1000 Ljubljana

IDEXX Laboratories Italia, Via Guglielmo Silva 36, 20149 Milano, Italija

Kemofarmacija d.d., Cesta na Brdo 100, 1000 Ljubljana

Merck MSD AH, Intervet international B.V. Boxmeer, Podružnica Ljubljana, Šmartinska cesta 140, 1000 Ljubljana

Metalka Media d.o.o., Dalmatinova 2, 1000 Ljubljana

MM Surgical d.o.o., Galjevica 81, 1000 Ljubljana

Royal Canin Ljubljana d.o.o., Letališka c. 29/A, 1000 Ljubljana

Vetpet d.o.o., Letališka cesta 29, 1000 Ljubljana



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ORGANIZACIJSKI IN UREDNIŠKI ODBOR SZVMŽ (UO SZVMŽ)

Doc. dr. Alenka Seliškar, dr. vet. med. (predsednica)

Prof. dr. Nataša Tozon, dr. vet. med. (podpredsednica – bodoča predsednica)

Igor Firm, dr. vet. med. (podpredsednik – prejšnji predsednik)

Barbara Celinšek, dr. vet. med. (tajnik)

Tjaša Pukl, dr. vet. med. (blagajnik)

Milan Matko, dr. vet. med. (član)

Doc. dr. Joško Račnik, dr. vet. med. (član)

ČASTNI ČLANI ZDRUŽENJA:

Prof. dr. Vjekoslav Simčič, dr. vet. med.

Prof. dr. Boyd R Jones, BVSc, FACVSc, DECVIM-Ca, MRCVS

Emil Mlinarič, dr. vet. med.

WORLD SMALL ANIMAL VETERINARY ASSOCIATION - WSAVA

OFFICERS

Prof. Colin Burrows, Executive Board Member, President

Prof. Jolle Kirpensteijn, Past President

Dr. Walt Ingwersen, President Elect

Dr. Shane Ryan, Executive Board Member, Vice-President

Dr. Siraya Chunekamrai, Honorary Secretary

Dr. Ellen van Nierop, Honorary Treasurer

Dr. Renée Chalmers Hoynck van Papendrecht, Executive Board Member

Dr. Nicola Neumann, Executive Board Member

FEDERATION OF EUROPEAN COMPANION ANIMAL VETERINARY ASSOCIATIONS - FECAVA

OFFICERS

Dr. Jerzy Gawor, President

Dr. Wolfgang Dohne, Vice President

Dr. Ann Criel, Secretary

Dr. Denis Novak, Treasurer

Dr. Monique Megens, Senior Vice-President



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ČETRTEK, 7. april 2016 PREDKONGRESNI DAN – Ortopedija, (dvorana Adria) VOG-Veterinary Orthopaedics and Neurology Group(pokrovitelj Vetpromet)08.30 – 09.00 PRIJAVA UDELEŽENCEVModerator: Matko M 09.00 – 09.30 Lončar Z. Orthopaedics exam of the hip and elbow09.30 – 10.00 Zorko B. Slikovna diagnostika patologije kolka10.00 – 10.30 Petazzoni M: Hip dysplasia: Early diagnosis and treatment

10.30 – 11.00 ODMORModerator: Zorko B11.00 – 11.45 Petazzoni M. Hip dysplasia in growing dogs: Treatment decision making 11.45 – 12.30 Matko M. Artroskopska in slikovna diagnostika patologije komolca 12.30 – 13.15 Petazzoni M. Elbow dysplasia: Early diagnosis and treatment.

13.15 – 14.30 KOSILOModerator: Matko M14.30 – 15.15 Petazzoni M. TTTT-Tibial Tuberosity Transposition Tool and Technique 15.15 – 17.00 Matko M, Zorko B. Case presentation section and hip and elbow cross fire section

17.15 VOG meeting

ČETRTEK, 7. april 2016

PREDKONGRESNI DAN – Prostoživeče ptice v Sloveniji – od biologije do veterinarske oskrbe, (dvorana Pharos)14.00 – 14.30 PRIJAVA UDELEŽENCEVModerator: Račnik J14.30 – 15.15 Vrezec A. Vzroki pogina pri prostoživečih pticah in njihova biologija: vidik muzejskih evidenc 15.15 – 16.00 Račnik J. Prva veterinarska pomoč pri bolnih, oslabelih in poškodovanih prostoživečih pticah 16.00 – 16.45 Maričič P. Hranjenje in nega bolnih, oslabelih in poškodovanih prostoživečih ptic

16.45 – 17.15 ODMOR Moderator: Zadravec M17.15 – 18.00 Zadravec M. Trihomonoza pri prostoživečih pticah – klinične izkušnje18.00 – 18.45 Račnik J. Zadravec M. Nekateri klinični primeri bolezni in poškodb pri prostoživečih pticah 18.45 – 19.30 Trilar T. Zakaj ptice pojejo?

PETEK, 8. april 2016, Smaragdna dvorana08.30 – 09.00 PRIJAVA UDELEŽENCEV09.00 – 09.15 OTVORITEV SIMPOZIJAModerator: Tozon N09.15 – 10.00 Findji L. Principles of oncologic surgery10.00 – 10.45 Findji L. Skin reconstruction in oncologic surgery

10.45 – 11.15 ODMOR (pokrovitelj VetConsult Pharma)Moderator: Firm I11.15 – 12.45 Nemec A. Tumorji in načela onkološke kirurgije v ustni votlini

12.45 – 14.15 KOSILOModerator: Matko M14.15 – 15.00 Findji L. Canine and feline soft tissue sarcomas15.00 – 15.45 Findji L. Tumours of the body walls

15.45 – 16.15 ODMOR (pokrovitelj Krka)Moderator: Seliškar A16.15 – 17.00 Nemec A. Defekti neba

17.00 – 18.30 SKUPŠČINA SZVMŽ20.00 SVEČANA VEČERJA (Smaragdna dvorana, ansambel Victory)

SOBOTA, 9. april 2016

Program za VETERINARJE, Smaragdna dvoranaModerator: Firm I09.30 – 10.30 Sist B. Peri-operative pain management in dogs and cats (VetConsult Pharma/Richter Pharma)10.30 – 11.00 Tozon N, Lampreht Tratar U, Žnidar K, Serša G, Teissie J, Čemažar M. Elektrokemoterapija – operativni postopek

11.00 – 11.30 ODMOR (pokrovitelji IRIS, ELANCO, Natures Menu)Moderator: Matko M11.30 – 12.00 Butinar J, Rejec A, Benoit J. Resekcije tumorjev v kombinaciji z radioterapijo – multimodalni pristop k zdravljenju onkoloških pacientov12.00 – 12.30 Plavec T, Rupp S, Kessler M. Zasuk širokega črevesja pri psih in primerjava z zasuki želodca in mezenterialnega korena

12.30 – 14.00 KOSILOModerator: Račnik J14.00 – 14.30 Zadravec M, Račnik J, Nemec A, Bahč I. Prehrana malih rastlinojedih sesalcev z boleznimi zob14.30 – 15.00 Kvapil P, Kastelic M, Gorenšek M. Zlom radiusa in ulne pri zlatoličnem gibonu (Nomascus Gabrillae)15.00 – 15.30 Dolenšek T, Gombač M, Švara T. Patohistološka preiskava - kakšne so koristi za veterinarja praktika?15.30 ZAKLJUČEK SIMPOZIJA

SOBOTA, 9. april 2016

Program za VETERINARSKE TEHNIKE, (dvorana Adria)Moderator: Matko M09.30 – 10.15 Krofič Žel M. Oskrba in klinično spremljanje pacienta s kronično ledvično boleznijo10.15 – 11.00 Kožuh T. Surova prehrana kot del terapije (Natures Menu/IRIS)11.00 – 11.30 ODMOR (pokrovitelji IRIS, ELANCO, Natures Menu)Moderator: Račnik J11.30 – 12.15 Tozon N. Kaj moramo vedeti o odkrivanju, zdravljenju in predvsem preprečevanju nekaterih parazitarnih obolenj (ELANCO/IRIS)12.15 – 13.00 Pogorevc E. Ultrazvočna diagnostika malih živali

13.00 – 14.00 KOSILOModerator: Firm I14.00 – 14.45 Nemec A. Halo, veterina? Moj pes si je ravnokar zlomil zob ...14.45 – 15.30 Plavec T. Pozdravljeni, rad bi govoril s kirurgom… Najpogostejša vprašanja in (ne)enostavni odgovori

15.30 ZAKLJUČEK SIMPOZIJA

POSTERJI

1. Hudobivnik A. Uporaba akupunkture za lajšanje bolečin pri pacientu z lumbalno stenozo, artritisom komolca ter boreliozo

2. Kvapil P, Kastelic M, Zadravec M, Gombač M, Švara T, Golob M, Račnik J. Kloacitis pri bradatih agamah v živalskem vrtu Ljubljana

3. Praprotnik Borko Š. Kirurška sanacija mastocitoma pri zlati prinašalki

4. Trojner G, Kessler M. Torzija pljučnega režnja pri ruskem hrtu

5. Zakošek Pipan M, O’Connor C. Neustrezen spolni razvoj – trisomija X

PROGRAM XXIX. SIMPOZIJA O AKTUALNIH BOLEZNIH MALIH ŽIVALI, Portorož, 7. – 9. april 2016



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PRINCIPLES OF ONCOLOGIC SURGERY

Laurent Findji

Surgery has been and remains the mainstay of tumour treatment, except for cancers which are exclusively sys-temic (e.g. leukaemia), and most cancer cures in humans today still result from surgery alone.

Historically, surgeons were first limited in the extension of surgical excisions by their own technical insufficiencies and shortcomings of supporting disciplines such as anaes-thesia and intensive care medicine. As these progressed came the era of large resections. Initially, it appeared that wider resections improved the prognosis. However, this was only true to a certain point and, although local dis-ease control was more often achieved, metastatic disease remained an obstacle to cure. Surgery as sole treatment of cancer was obviously not the panacea.

The most efficient treatment of cancer is today multi-modal. It is now clear that surgeons should be members of a team including radiographers, anaesthetists, criticalists, pathologists, and medical and radiation oncologists. Sur-geons need to have a good knowledge of tumour biology to determine the role and contribution of surgery, for each case, to the whole treatment. They also need to under-stand how other therapies work, in order to adapt their surgical technique to previous or later treatments.

These are exciting perspectives for oncologic surgeons. Their role is constantly evolving as they increasingly work in close collaboration with other therapies such as chemo-therapy, radiotherapy and immunotherapy. Whilst the times of extensive, technically challenging resections are not over, the oncologic surgeon has evolved from a techni-cian to a more complete clinician, whose deep knowledge in cancer biology allows more concerted and tailored pro-cedures.

TYPES OF ONCOLOGIC SURGERY

Surgery for diagnosisBiopsies

Biopsies are crucial in the diagnosis process of tumours. They can be incisional or excisional. They are performed transcutaneously (core-needle biopsies), or by minimally-invasive or conventional surgery.

Staging surgerySurgery can be involved in tumour staging. Lymph

node biopsies (incisional or excisional) provide helpful information on locoregional spreading of a tumour. Ex-ploration of body cavities for signs of metastatic disease can also be performed, either when operating the main tumour (e.g. inspection of the abdomen when resecting an abdominal tumour) or separately. Minimally-invasive surgery (laparoscopy, thoracoscopy) is increasingly used in such indications.

Surgery for cureSurgery is most often performed with an intention to

cure, whether it be by surgery alone or combined with other therapies. Depending on the surgical “dosing”, sev-eral types of tumour resections are possible: cytoreductive or intracapsular, marginal, wide and radical.

Cytoreductive surgery consists of removing as much of the tumour as possible but leaving macroscopic disease behind. It is only considerable if some kind of adjuvant therapy is planned, in a view of potentiating this adjuvant treatment.

Marginal resections consist of excision of the tumour with minimal amounts of surrounding tissues. The likeli-hood of leaving microscopic residual disease is high and this type of resection should be avoided as much as pos-sible. However, in certain cases, it is preferable to more ex-tensive resections, either because of difficulties in wound reconstruction (e.g. tumours of extremities) or vicinity of non-expandable structures (e.g. brain tumours). In such cases, surgery should be followed by adjuvant therapy, ra-diotherapy especially.

Wide resections consist of excision of the tumour with enough surrounding tissues to expect complete excision including microscopic disease. This is the type of resection to seek as often as possible. Its main limitation comes from the fact that precise guidelines as to necessary margins are lacking. Therefore, in some cases, microscopic disease

Laurent Findji DMV MS MRCVS DiplECVS Fitzpatrick Referrals Guildford GU7 2AJ, United Kingdom



9

remains, leading to recurrence. Good communication with the pathologist is essential to have as precise an assess-ment of the excision margins as possible.

Radical resections consist in even wider resections. Of-ten, it consists of the excision of body parts (amputations). A good definition is that after radical excision, there is no need to await the pathology results to know that the mar-gins are clear.

Surgery for palliationPalliative surgery is performed to improve the patient’s

quality of life, without extending its life expectancy. Am-putation for an appendicular osteosarcoma and splenec-tomy on a haemangiosarcoma are two examples of pallia-tive surgeries, as they do not improve survival times per se.

Surgery for cancer preventionSome cancers, such as hormone-dependant cancers,

can be prevented by surgical procedures: prepubertal ova-riectomy in dogs dramatically reduces the risk of mam-mary tumour; castration of dogs prevents the occurrence of testicular tumours and perianal adenomas; etc.

Surgery for medical supportPlacement of feeding tubes can be necessary to sup-

port nutrition of cancer patients. Cachexia is a major con-cern in some cancer patients. Nutritional support is known to decrease associated morbidity in humans.

Surgery for treatment device implantationSurgeons can play a part in non-surgical treatments by

placing several types of implants such as vascular access ports, intracavitary catheters, brachytherapy catheters, etc.

ONCOLOGIC SURGERY TECHNIQUES

BiopsiesBiopsies can be incisional or excisional. Incisional biop-

sies consist of sampling a portion of the tumour to allow histopathological determination of its nature. Excisional biopsies consist of the complete excision of the tumour prior to any histopathological diagnosis.

Excisional biopsies should only be chosen when knowl-edge of the tumour type would not alter the surgical dose required for resection. Excessive and inappropriate use of marginal excisional biopsies is a major cause for cancer treatment failure. If in doubt, perform fine-needle aspi-rates or an incisional biopsy to ascertain that the subse-quent resection plan is appropriate.

In general, it is best to biopsy at the junction between healthy and tumoral tissues, so that the pathologist can study the characteristics of the tumour invasion in sur-rounding tissues. Also, many tumours are necrotic, in-flammatory or infected in their centre, which may lead to misdiagnosis. However, some tumours, such as osteosar-coma, should be biopsied in their centre as they induce a strong reaction within surrounding tissues, which may lead to misdiagnosis if biopsied in periphery1. In addition, if the surrounding tissues are essential for later reconstruc-

tion, they should not be included in the biopsy. Overall, it is crucial not to jeopardise later treatments by performing biopsies in a way that the biopsy tract can be later excised en-bloc with the tumour.

Fine-needle aspiration and cytological examination of the regional lymph nodes should be performed, regardless of their palpation and size, as they are not reliable indica-tors of lymph node metastasis. However, tumours do not necessarily drain to the closest lymph node and may even drain controlaterally. Therefore, ideally, individual map-ping of the tumour drainage should be obtained to deter-mine the position of the sentinel lymph nodes, which are the first to which the tumour drains and whose aspiration therefore is the most sensitive for detection of metasta-sis2. This is increasingly performed in oncology specialist centres and should become more common in the future. In the absence of sentinel lymph node mapping, it can only be recommended to sample as many regional lymph nodes as possible, as long as their biopsy does not increase surgical time and risk excessively.

Tumour resectionThe most important point, when planning surgery

for tumour resection, is to balance the consequences of surgery and potential complications against the expect-ed benefits. In other words, the treatment should never be worse than the disease! It is easy for surgeons to be tempted to perform technically challenging procedures, which turn out to be of no significant benefit for the patient. Inversely, surgeons should not deter owners to proceed with some apparently extensive, but well toler-ated, surgeries (amputations, extensive mandibulectomies / maxillectomies, etc.) because they personally feel uncom-fortable with them. Referral should then be offered.

It is crucial that surgeons place the patient’s welfare first, before owners’ wishes. In-depth discussion with the owners will allow understanding what their expectations are and whether they can be met by possible treatments. This will avoid misunderstandings and later issues.

Knowledge of the tumour type and biology is para-mount in appropriate surgical planning. The surgical “dose” depends on it. The first surgery is the best chance to cure, it should not be wasted.

As often as possible, tumours should be resected widely. Fear of not being able to close the resulting de-fect should not limit the resection extension. Depending on the tumour type and size, 1 to 3-cm lateral margins are generally recommended. Some surgeons advocate for even wider (5-cm) lateral margins for excision of soft tissue sarcomas in cats3. In depth, depending on tumour type and size, one or two fascial planes should be excised en-bloc with the tumour.

Alternatively, if an adjuvant treatment is planned (ra-diotherapy especially), the surgical excision can be more conservative. Taking intraoperative pictures and leaving metallic vascular clips at the margins of excision can then help the radiation oncologist plan subsequent treatments.



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Tumours should be manipulated as little and as gently as possible to prevent seeding of tumour cells. Ideally, the tumour should not be approached or visualised and only healthy surrounding tissues be manipulated. Previous bi-opsy and drain tracts are excised en-bloc with the tumour. Whenever possible, major arteriovenous pedicles should be ligated as early as possible in the procedure and veins be ligated before arteries to limit the risk of macroscopic embolisation of tumour cells when the tumour is manipu-lated.

Tumour should be treated as an infection: any tissues, instruments, gloves and drapes which may have been contaminated by tumour cells should be changed. The same instruments should not be used to excise, or biopsy, two separate masses. Similarly, when closing the surgical wound, it is important to remember that any distant tis-sues used (skin flaps for instance) will be considered con-taminated if any subsequent treatment is required. Using large skin flaps after tumour excision should be avoided if the tumour margins are not known to be clear. It could lead to tumour seeding and recurrence away from the initial site and prevent adjuvant radiotherapy as the irra-diation field would become too large. An option allowing skin flaps to be used in the face of uncertain margins is to harvest the flap before starting the tumour resection. I regularly use this approach, which requires careful surgical planning.

Postoperative care should be anticipated. Enteral feeding tubes should be placed as appropriate. Similarly, wound catheters can be left in surgical wounds, allowing regular instillation of local anaesthetics in the wound.

Even if the tumour has previously been biopsied, the entire piece of excision is fixed in 10% formalin and sub-mitted for pathology.

POSTOPERATIVE CARE

Non-specifically, postoperative care of cancer patients include wound care, analgesia, nutritional support, and medical care as appropriate. Depending on the tumour type, specific treatments of paraneoplastic treatments can be required (e.g. blood levels monitoring and manage-ment of calcium in patients with hyperparathyroidism or of glucose in patients with insulinomas, etc.). Depending on the procedure performed, specific management may be required (chest drain for thoracic tumours, nursing on animals with spinal tumours, rehabilitation for amputees, etc.).

When adjuvant therapies are planned, they are initi-ated as soon as possible. Usually, chemotherapy can be started early, most often 7 to 10 days after surgery. Al-though most chemotherapeutic agents experimentally im-pair wound healing, it is of little, if any, clinical relevance. On the other hand, radiotherapy has a clear detrimental effect on wound healing and it is most often only initiated after wound healing is complete, i.e. 2 to 3 weeks after surgery.

References

1. Ehrhart NP, Culp WTN. Principles of oncologic surgery. In: Kudnig ST, Séguin B (eds): Veterinary surgical oncology. Oxford: Wiley-Blackwell, 2012;3-13.

2. Tuohy JL, Milgram J, Worley DR, Dernell WS. A review of sentinel lymph node evaluation and the need for its incorporation into veterinary oncology. Veterinary and Comparative Oncology. 2009;7: 81-91.

3. Phelps HA, Kuntz CA, Milner RJ, Powers BE, Bacon NJ. Radical excision with five-centimeter margins for treatment of feline injection-site sarcomas: 91 cases (1998-2002). Journal of the American Veterinary Medical Association. 2011;239: 97-106.



11

SKIN RECONSTRUCTION IN ONCOLOGIC SURGERY

Laurent Findji

It is essential for oncologic surgeons to have a deep knowledge of reconstruction techniques. Indeed, limita-tions in the ability to reconstruct a wound should not lead to insufficiently wide resections. The greater the recon-struction abilities of the surgeon, the more comfortable they will be administering the appropriate dose of surgery in the face of a large or awkwardly located tumour.

Reconstructive surgery is an extensive subset of sur-gical science. It is presented exhaustively in a number of textbooks1-3. Only basic notions and particular points per-taining to oncologic surgery can be discussed here.

Vascular anatomy of the skin

In dogs and cats, the skin is vascularised by 3 plexi: the subpapillary, cutaneous and subdermal plexi. The two most superficial plexuses depend on the subdermal plexus, which is therefore the most important to preserve. This subdermal plexus lies in depth of the hypodermis. In re-gions of the body where a panniculus muscle is present (trunk, neck), the subdermal plexus runs immediately deeply and superficially to it. As a practical consequence, when the skin is undermined for primary closure or perfor-mance of a skin flap, it must be elevated in depth of the panniculus muscle. In areas where no such muscle is pre-sent, the skin must be elevated as close as possible from the underlying fascial or muscular plane.

Wound closure options

Simple closureWound closure may be primary (immediate), delayed

primary (before formation of granulation tissue) or sec-ondary (after formation of granulation tissue). Delayed pri-mary and secondary closures are recommended by some surgeons when margin status is uncertain after tumour removal4: the wound is managed as an open wound for a few days while pathology results and margin assessment are pending. When the margins are known to be free of tumour, the wound is closed surgically using any available technique (simple closure, skin flap, skin graft). Several techniques (tension-relieving sutures and incisions, plas-ties) are available to achieve wound closure when simple closure is not possible. Alternatively, the wound may be left to heal by second intention.


Figure : Vascular anatomy of the skin

(a: epidermis; b: dermis; c: panniculus muscle; d: squelettal muscle; 1: subpapillary plexus; 2: cutaneous plexus; 3: subdermal plexus; 4: hypodermis; arrow: direct cutaneous artery)



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Skin flaps

Skin flaps are either subdermal (relying on the subder-mal vascular plexus) or axial (relying on a direct cutaneous artery).

Subdermal flaps are sometimes referred to as “ran-dom” flaps, as they rely on the random subdermal plexus to vascularise the elevated skin. This means that these flaps can be harvested in any location and direction. How-ever, the perfusion pressure of the elevated skin has to be estimated as an empirical statistical notion, as the po-tential presence and direction of direct cutaneous arteries supplying the elevated skin are unknown (Figure 2). As a consequence, these flaps can only be elevated on a limited length, and their base need to be at least as wide as their free end. As an empirical rule, subdermal flaps should only be 1.5 to 2 times longer than they are wide.

Figure 2: Vascularisation subdermal flaps

Subdermal flaps can either be local or distant.

Local flaps include advancement (Figure 3), rotation (Figure 4), transposition (Figure 5) and interpolation flaps (Figure 6). These flaps are elevated from skin adjacent to the wound.

Figure 3: Advancement flap

Figure 4: Rotation flap

Figure 5: Transposition flap

Figure 6: Interpolation flap



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Distant flaps include hinge and pouch flaps, in which a monopedicular or bipedicular subdermal flap is elevated on the lateral aspect of the abdomen or thorax and used to cover a wound on the distal portion of a limb brought to the flap (Figure 7).

Figure 7: Principle of distant flaps

Axial pattern flaps are determined by the area of skin vascularised by a major direct cutaneous artery (angio-some), after which it is named (Figure 8a). Many direct cutaneous arteries which can be used to perform axial flaps have been described (Figure 9). Provided this artery is preserved, such flaps are more robust and survive on greater lengths compared to equivalent subdermal flaps. They can even be islanded, i.e. entirely cut out from the donor site apart from their vascular pedicle (Figure 8b). However, axial flaps cannot be elevated in any direction: their design has to follow the description of the cutaneous area vascularised by the chosen direct cutaneous artery. The most commonly used axial flaps include the caudal superficial epigastric, thoracodorsal, omocervical, deep cir-cumflex iliac and caudal auricular flaps.

Figure 8: Vascularisation of axial flaps (a). Island flap (b)

Figure 9: Main direct cutaneous arteries of the dog

Skin flaps, either subdermal or axial, are transposed with their own vascularisation and can survive on poorly vascular beds or over cavities.

Skin grafts

Skin grafts consist of transposing free portions of par-tial-thickness or full-thickness skin to a wound. The trans-posed skin is therefore no longer perfused and relies on the development of a neovascularisation from the receiv-ing bed for survival. The receiving bed must therefore be healthy and well-vascularised, so that sufficient neovascu-larisation can develop from it.

In veterinary surgery full-thickness grafts, harvested from the ventrolateral portions of the trunk, are most commonly used. Different forms of grafts exist: meshed, unmeshed, pinch, punch and strip grafts.

Meshed and unmeshed grafts use a single skin por-tion to cover the recipient bed. Numerous slit incisions are made in meshed grafts. These incisions allow postopera-tive drainage which favours graft adhesion and survival. In addition, meshed grafts can be expanded more easily than unmeshed grafts.

Pinch and punch grafts consist of a number of few-millimetre-wide portions of skin placed evenly apart in the recipient bed. Pinch grafts are harvested with a scalpel, whereas punch grafts are harvested with a biopsy punch. Matching-size holes or pockets are created in the granula-tion tissue of the recipient bed to accommodate the grafts. The main advantages of these grafts are that they are easy to perform, allow very good drainage of the wound and withstand infection better than other types of graft. How-ever, the resulting cosmetic aspect is rather poor.

Strip grafts consist of several strips of skin placed par-allel in the recipient bed. Matching-size strips of granula-tion tissue are excised to accommodate the grafts. Like pinch and punch grafts, these grafts allow good drainage but often lead to poor cosmetic results.

Wound closure decision making

Wound closure options depend on the location, age, type, severity and contamination of the wound. In small

a

b



14

animals, the great skin elasticity allows primary or second-ary closure of many wounds. If not, the wound can either be left to heal by second intention or more advanced re-constructive techniques be used to achieve wound closure. Second intention healing may seem financially attractive at first, but it is often long to complete, requires numer-ous dressing/bandages and regular follow-up, which may eventually cost more than a reconstructive surgery. In ad-dition, it often leaves an epithelium of poor quality and cosmetics, and occasionally results in skin contractures.

Skin flaps and grafts can be used to avoid these draw-backs.

In all cases, the surgeon must opt for the technique which, in his hands, is the safest, simplest and cheapest. The technique with the greatest chances of success must be chosen in priority. If several techniques have equal chances of success, the simplest must be preferred. Lastly, the financial aspect may also be accounted for and the cheapest method among the most likely to be successful may also be chosen.

References

1. Pavletic MM. Atlas of small animal wound management and reconstructive surgery. Oxford: Wiley-Blackwell, 2010.

2. Williams J, Moores A. BSAVA manual of canine and feline wound management and reconstruction. Quedgeley: British Small Animal Veterinary Association, 2009.

3. Slatter DH. Textbook of small animal surgery. Philadelphia, PA ; [Great Britain]: Saunders, 2003.

4. Liptak J. The Principles of Surgical Oncology: Surgery and Multimodality Therapy. Compendium Continuing Education for Veterinarians. 2009;31: 14 p.



15

NOVOTVORBE V USTNI VOTLINI IN NAČELA ONKOLOŠKE KIRURGIJE V USTNI VOTLINI

Ana Nemec

Klasifikacija novotvorb v ustni votlini

Ustna votlina je peto najpogostejše mesto za pojav novotvorb pri psih in tretje najpogostejše pri mačkah, pri čemer maligne novotvorbe ustne votline predstavljajo 6% vseh novotvorb. Glede na biološko vedenje novotvorbe ustne votline opišemo kot maligne ali benigne novotvorbe. Histološko pa novotvorbe ustne votline lahko razvrstimo med neodontogene ali odontogene novotvorbe ter ne-neoplastične proliferativne spremembe.

Neodontogene novotvorbeNajpogostejše neodontogene novotvorbe ustne votline

psov in mačk so ploščatocelični karcinom (SCC), maligni melanom (MM), fibrosarkom (FSA) in osteosarkom (OSA). Prav tako pa v ustni votlini lahko diagnosticiramo multilob-ularni osteohondrosarkom, ekstramedularni plazmocitom, limfom, mastocitom, hemangiosarkom, fibrom, osteom in druge redke neodontogene novotvorbe.

Ploščatocelični karcinom je najpogostejša novo-tvorba ustne votline pri mačkah in druga najpogostejša pri psih. Je invazivna epitelijska novotvorba, ki pogosto vrašča v kost. Večinoma izvira iz zobnega dela čeljusti in zaseva pozno in sorazmerno redko. Tonzilarni SCC in SCC pri mačkah zasevata prej (regionalne bezgavke in pljuča) in pogosteje. Prognoza je odlična pri psih ob zgodnji diag-nozi in radikalnem zdravljenju. Prognoza za SCC jezika in tonzil ter za SCC pri mačkah je slaba.

Maligni melanom je najpogostejša novotvorba ustne votline pri psih in redka pri mačkah. Histološka diagnos-tika je lahko zapletena zaradi različnih tipov MM. Maligni melanom pogosto vrašča v kost in pogosto ter zgodaj za-seva (regionalne bezgavke, pljuča). Prognoza je najslabša za MM ustne votline, nekoliko boljša je za ustnični MM (in najboljša za MM kože).

Fibrosarkom je druga najpogostejša novotvorba ustne votline pri mačkah in tretja pri psih. Pri psih (zlasti zlati prinašalci) je opisan tudi t.i. »high-low« podtip FSA, ka-terega histološke značilnosti so tiste benignih novotvorb, vendar je biološko izjemno agresiven. Fibrosarkom najpo-gosteje najdemo na dlesni zgornje čeljusti in trdem nebu in je lokalno zelo invaziven, čeprav sorazmerno redko zaseva. Prognoza je zaradi pogosto neuspešne lokalne kontrole bolezni sorazmerno slaba, vendar je odvisna od lokacije novotvorbe (prognoza je najslabša za novotvorbe neba), velikosti, načina zdravljenja in histološkega gradusa.

Osteosarkom je lokalno izjemno invazivna novotvor-ba, ki sorazmerno redko zaseva. Prognoza je sorazmerno slaba zaradi pogoste lokalne ponovitve in napredovanja bolezni. Multilobularni osteohondrosarkom je novotvorba ploščatih kosti glave.

Odontogene novotvorbeOdontogene novotvorbe so pogoste pri psih in redke

pri mačkah. Glede na tkivni izvor jih delimo na epitelijske, mezenhimske in mešane. Odontogene novotvorbe so po-navadi lokalno agresivne, vendar ne zasevajo. Maligne od-ontogene novotvorbe so izjemno redke, zato je prognoza za odontogene novotvorbe najpogostejše odlična.

Pasji akantomatozni ameloblastom (CAA; »akan-tomatozni epulis« - v opuščanju) je lokalno invazivna epitelijska novotvorba z odlično prognozo ob popolni re-sekciji.

Periferni odontogeni fibrom (POF; »fibromatozni, osificirajoči epulis« - v opuščanju) je lokalno invazivna mezenhimska novotvorba z odlično prognozo ob popolni resekciji.

Odontom je induktivna mešana novotvorba, ki bi lahko bila tudi hamartom. Diagnosticiramo jo večinoma pri mladih živalih. Prognoza je ob popolni neinvazivni odstran-itvi odlična.

Ne-neoplastične proliferativne spremembeV ustni votlini lahko diagnosticiramo številne ne-

neoplastične proliferativne spremembe, kot so fokalna ali generalizirana hiperplazija dlesni, preraščanje dlesni, pio-geni granulom, periferni granulom velikih celic, reaktivna eksostoza, travmatska hiperplazija sluznice, papilomatoza in eozinofilni granulom, plak ali ulkus.

Doc. dr. Ana Nemec, dr. vet. med., spec. med. psov in mačk, Dipl. AVDC, Dipl. EVDC Klinika za male živali, Veterinarska fakulteta, Univerza v Ljubljani, Slovenija; Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, USA; e-pošta: [email protected]; www.kkmz.si



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Diagnostični postopki

Najpomembnejša napovedna dejavnika pri živalih z no-votvorbo v ustni votlini sta vrsta novotvorbe in zamejitev bolezni. Pri določanju zamejitve bolezni se poslužujemo TNM sistema, pri čemer s »T« opišemo primarni tumor, z »N« vpletenost regionalnih bezgavk in z »M« morebitne oddaljene zasevke. Da lahko določimo TNM, moramo opraviti popoln klinični pregled ter ustrezno laboratorijsko in slikovno diagnostiko.

Primarna novotvorbaDa določimo vrsto novotvorbe, moramo opraviti biop-

sijo. Biopsijo v idealnih razmerah opravimo po opravljeni slikovni diagnostiki, saj tako najbolje načrtujemo odvzem dobrega vzorca tkiva in se obenem izognemo morebitnim pomembnim strukutram v okolici. Večinoma opravljamo incizijsko biopsijo po odprti metodi, pri čemer (če velikost novotvorbe dopušča) odvzamemo vsaj 2 vzorca iz globine več kot 2 mm, pri tem pa se izogibamo mestom nekroze in ulceracije. Mesto biopsije in pot inštrumenta morata biti kasneje vključena v polje resekcije (ali obsevanja). Zelo pomembno je, da primer opišemo patohistologu in se z njim tudi temeljito pogovorimo ob kakršnemkoli dvomu ter upoštevamo načela klinično-patološke korelacije.

Velikost novotvorbe je izjemnega pomena pri načrtovanju zdravljenja in predvidevanju poteka bolezni. Obseg novotvorbe, zlasti pri velikih novotvorbah in novo-tvorbah kavdalno v ustni votlini in/ali na zgornji čeljusti, določimo najbolje z računalniško tomografijo (CT) glave, pri čemer naredimo 1-mm rezine pred in po aplikaciji kon-trastne snovi, v polje pa vključimo tudi vse regionalne bez-gavke.

Regionalne bezgavkePalpacija bezgavk je nezanesljiva, saj tudi na otip nor-

malne bezgavke lahko vsebujejo zasevke, obenem pa večine regionalnih bezgavk glave ne tipamo. Tankoigel-na biopsija bezgavk je trenutno najbolj uveljavljena me-toda pregleda. Rutinsko opravljamo tankoigelno biopsijo enostavno dostopnih čeljustnih bezgavk. Vedno odvzam-emo vzorce iz bezgavk na obeh straneh, ne glede na lokacijo novotvorbe v ustni votlini, saj je potek dreniranja limfe iz ustne votline nepredvidljiv. Še bolje je, če CT izvid bezgavk po potrebi kombiniramo z ultrazvočno vodeno tankoigelno biopsijo retrofaringealnih bezgavk, ki so glav-ni zbirni center limfe glave. Negativen izvid tankoigelne biopsije bezgavk pa tudi ne pomeni zanesljivo odsotnosti zasevkov. Ekscizijska biopsija vseh bezgavk glave in vratu je kontroverzen poseg, saj sam po sebi predstavlja obsežen kirurški poseg. Vedno bolj se stremi k ekscizijski biopsiji bezgavk, ki prve drenirajo območje novotvorbe (ang. sen-tinel node), pri čemer pa obstajajo v veterini še vedno precejšnji diagnostični izzivi.

Oddaljeni zasevkiZamejitev bolezni po TNM klasifikaciji zaokrožimo z

ultrazvočno preiskavo trebuha ter rentgenskim slikanjem ali, še bolje, CT prsnega koša. Z rentgenskim slikanjem (v treh projekcijah) zaznamo zgolj 9% pljučnih nodulov, ki jih sicer diagnosticiramo s CT pri psih z zasevki v pljučih.

Zdravljenje in prognoza

Metode zdravljenja novotvorb ustne votline so številne (npr. kirurško zdravljenje, obsevanje, elektrokemo-/ele-ktrogenska terapija, kemoterapija, imunoterapija), zato je najbolje, da ekipa specialistov (ki jo v idealnih razme-rah sestavljajo veterinarski stomatolog, kirurg, onkolog, radiacijski onkolog, internist, anesteziolog in specialist slikovne diagnostike) pripravi načrt zdravljenja za vsakega posameznega pacienta glede na vrsto novotvorbe, zame-jitev bolezni, morebitne ostale bolezni in starost pacienta ter želje in finančne zmogljivosti lastnika. Veterinar mora lastnika živali obvestiti o poteku zdravljenja, prognozi, morebitnih neželenih učinkih zdravljenja, pooperacijskem okrevanju in izgledu živali ter stroških zdravljenja, pred pričetkom zdravljenja.

Kirurško zdravljenje je trenutno najpogostejša me-toda zdravljenja, ki pa ima glede na vrsto in velikost tu-morja ter morebitno prisotnost zasevkov lahko različen cilj – ozdravitev pacienta (npr. večina majhnih/zgodaj od-kritih neodontogenih in zlasti odontogenih novotvorb), zmanjšanje tumorske mase (npr. neoperabilne novotvorbe pred obsevanjem), lokalno kontrolo bolezni (npr. opera-bilni melanom), paliativno zdravljenje (npr. velike novo-tvorbe, ki motijo normalno hranjenje živali). Cilj si lahko pravilno zastavimo le po opravljeni natančni diagnostiki in na podlagi tega načrtujemo kirurško ekscizijo, ki je lahko intrakapsularna (ostanejo ostanki tumorskega tkiva - npr. pri cilju paliativnega zdravljenja ali zmanjšanja tumorske mase), marginalna (vključuje psevdokapsulo tumorja, lahko ostanejo tumorske celice – npr. zdravljenje dobro diferenciranih benignih tumorjev), široka (vključuje tumor, psevdokapsulo, reaktivno cono in ponavadi 1 – 2 cm vid-no zdravega tkiva, odvisno od vrste tumorja – npr. delna maksilektomija z namenom ozdravitve SCC) ali radikalna (odstranitev celotne anatomske strukture ali kompart-menta s tumorjem). Kirurške tehnike in z njimi povezane spremembe videza in funkcije živali so različne in bodo predstavljene na podlagi kliničnih primerov

Literatura

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Armbrust LJ, Biller DS, Bamford A, et al. Comparison of three-view thoracic radiography and computed tomography for detection of pulmonary nodules in dogs with neoplasia. J Am Vet Med Assoc 2012; 240: 1088-1094.

Arzi B, Verstraete FJM. Clinical staging and biopsy of maxillofacial tumors. In: Verstraete FJM, Lommer M, eds. Oral and maxillofacial surgery in dogs and cats. Edinburgh: Saunders Elsevier, 2012: 373-380.

Barnes L, Eveson JW, Reichart P, et al. World Health Organization Classification of Tumours. Pathology and Genetics of Head and Neck Tumours. Lyon: IARC Press, 2005.

Bonello D, Roy CG, Verstraete FJM. Non-neoplastic proliferative oral lesions. In: Verstraete FJM, Lommer M, eds. Oral and maxillofacial surgery in dogs and cats. Edinburgh: Saunders Elsevier, 2012: 411-421.



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Boston SE, Lu X, Culp WT, et al. Efficacy of systemic adjuvant therapies administered to dogs after excision of oral malignant melanomas: 151 cases (2001-2012). J Am Vet Med Assoc 2014; 245(4): 401-407.

Chamberlain TP, Lommer MJ (2012). Clinical behavior of odontogenic tumors. In: Verstraete FJM, Lommer M, eds. Oral and maxillofacial surgery in dogs and cats. Edinburgh: Saunders Elsevier, 2012: 403-410.

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Culp WT, Ehrhart N, Withrow SJ, et al. DC. Results of surgical excision and evaluation of factors associated with survival time in dogs with lingual neoplasia: 97 cases (1995-2008). J Am Vet Med Assoc 2013; 242(10): 1392-1397.

Evans SM, Shofer F. Canine oral non-tonsillar squamous cell carcinoma. Prognostic factors for recurrence and survival following orthovoltage radiation therapy. Vet Radiol 1988; 29: 133-137.

Farcas N, Arzi B, Verstraete FJ. Oral and maxillofacial osteosarcoma in dogs: a review. Vet Comp Oncol 2014; 12(3): 169-180.

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Fiani N, Verstraete FJ, Kass PH, et al. Clinicopathologic characterization of odontogenic tumors and focal fibrous hyperplasia in dogs: 152 cases (1995-2005). J Am Vet Med Assoc 2011; 238: 495-500.

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18

CANINE AND FELINE SOFT TISSUE SARCOMAS

Laurent Findji

The term soft tissue sarcoma (STS) refers to a group of mesenchymal tumours originating in soft tissues (connec-tive, adipose, muscular, nervous and fibrous tissues) and sharing somewhat similar pathological appearances and biological behaviours. These tumours are classically re-ported to be potentially locally aggressive (pseudo-encap-sulated, easily spread along and through fascial planes), with a marked tendency to recur when incompletely re-sected but a limited metastatic potential. For most STS, the preferred route for metastasis is haematogeneous. In general, their histopathological grade is predictive for local recurrence and metastasis, and surgical margins after exci-sion are predictive for local recurrence. The most common tumour types of the STS of the skin and subcutis include fi-brosarcoma, peripheral nerve sheath tumour, perivascular wall tumour (haemangiopericytoma), myxosarcoma and liposarcoma. Although histiocytic sarcomas, lymphangio-sarcomas and haemangiosarcomas are by definition soft tissue sarcomas, they are often not considered as such because their different, more aggressive biological behav-iour, which warrants to consider and treat them differently from other, more classic STSs.

Although STS can occur anywhere in the body (e.g. splenic haemangiosarcoma, intestinal leiomyosarcoma, urinary bladder rhabdomyosarcoma), this text will focus on cutaneous and subcutaneous STS.

In cats, a particular type of STS is feline injection-site sarcomas, whose aetiology, clinical presentation and bio-logical behaviour differs from other canine and feline STS to some degree. They will be discussed separately at the end of this text.

Epidemiology, clinical signs and diagnosis

The median age of animals affected with STS is 10 years (5-17 years) in dogs and 8 to 11 years in cats (1-17 years). The reported proportions of STS among all cutane-ous and subcutaneous tumours are 8% to 15% in dogs, and 7% to 18% of in cats2.

Cutaneous and subcutaneous STS tend to be firm, ad-herent, slow-growing masses. The clinical signs associated with them largely depend on their location and relation-ships with surrounding anatomical structures. Typically, STS are not associated with significant systemic effects, although some paraneoplastic syndromes can be encoun-tered, such as hypoglycaemia with muscle tumours (leio-myomas, leiomyosarcomas, rhabdomyosarcomas), and anaemia and thrombocytopenia with HSAs and dissemi-nated histiocytic sarcomas.

Fine-needle aspirations (FNAs) are recommended to rule out non-neoplastic lesions and to differentiate mes-enchymal tumours from round cell tumours. However, STS tend to not exfoliate well and give poorly cellular sam-ples. In one study, FNAs lead to a correct diagnosis in only 62.5% of STS, whereas 96% of mast cell tumours were correctly diagnosed3. Fine-needle aspirations are also rec-ommended for evaluation of regional lymph nodes for high-grade tumours or the untypical STS which have a propensity to metastasise to lymph nodes (e.g. synovial cell sarcomas, histiocytic sarcomas, lymphangiosarcomas, haemangiosarcomas).

Biopsies of the primary mass are therefore recom-mended. Core-needle or incisional biopsies are preferred, as excisional biopsies are fraught with the risk of achieving insufficient margins, which complicates further treatments and jeopardises the clinical response and overall survival.

Advanced imaging (CT scan, MRI) is most helpful in the local staging (T staging) of the tumour. It allows de-termination of the tumours extension in 3 dimensions and identification of the surrounding anatomical structures, which greatly facilitates the treatment planning of the lo-cal disease, whether it be surgery, radiotherapy or both.

STS tend to spread haematogeneously, preferentially to the lungs, and metastasis to regional lymph nodes is uncommon, except for synovial cell sarcomas. Distant staging (M staging) should therefore always include imag-ing of the chest either through 3 radiographic views or CT scan of the chest, knowing that CT is more sensitive than conventional radiographs for detection of thoracic meta-static disease4.

The gathered information (tumour diagnosis and grade, and TNM staging) is used to define the tumour stage (Table 1).




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T Primary tumour

TX Primary tumour cannot be assessed

T0 No evidence of primary tumour

T1 Tumour 5 cm in greatest dimension

T2a Superficial tumour*

T2b Deep tumour*

N Regional lymph nodes

NX Regional lymph nodes cannot be assessed

N0 No regional lymph node metastasis

N1 Regional lymph node metastasis

M Distant metastasis

MX Distant metastasis cannot be assessed

M0 No distant metastasis

M1 Distant metastasis

G Histologic grade

GX Grade cannot be assessed

G1 Low (grade I)

G2 Intermediate (grade II)

G3 High (Grade III)

Stage

I G1–2 Any T N0 M0II G3 T1a-b,T2a N0 M0III G3 T2b N0 M0IV Any G Any T N1 Any M

Any G Any T Any N M1

* A superficial tumour is a tumour located above the superficial fascia and not invading it.

A deep tumour is located deep to the superficial fascia, invades it, or both.

Adapted from Ryan et al.2

Table 1: TNM staging and grading of soft tissue sarcomas

Treatment

Since typical STS metastasise infrequently but have a marked propensity for local recurrence, the main con-cern in their treatment most often is local tumour control. Therefore, complete surgical excision is the treatment of choice, whenever possible. When surgery is unlikely or fails to provide sufficient margins, it can be combined with radiotherapy, either in an adjuvant or neoadjuvant setting. When surgery is not possible, radiotherapy can be consid-ered as the main treatment, although it is most likely to only be palliative in the face of macroscopic disease. Lastly, the role of chemotherapy in the treatment of typical STS is unclear, although new protocols (local or metronomic chemotherapy) may prove of value.

SurgeryThe surgical treatment of STS should abide by the rules

of oncologic surgery. The surgical treatment of STS should abide by the rules of oncologic surgery. In all cases, com-plete excision should be thought. The width of surgical margins to be sought should be determined on a case-ba-sis. When possible, 1-3 cm lateral margins and 1-2 fascial plane in depth should be sought, depending on each par-

ticular tumour, taking into consideration its location, clini-cal features (inflammation, invasion, adhesion to underly-ing structures, size, rate of growth, biopsy grading, etc.). Absolute recommendations applicable to all canine soft tissue sarcoma can however not be made, and increasing evidence exists that tumour biology, and not the size of surgical margins, is the main determinant of the outcome in dogs5, 6. It is essential to keep in mind that STS may seem encapsulated but that they are only surrounded by a pseudocapsule actually constituted of compacted tumour cells. Therefore, a marginal or narrow excision should not be considered a satisfactory primary surgical objective.

One potential exception concerns low-grade STS of the extremities, for which marginal resection may provide satisfactory local tumour control and survival times. Recur-rence rates of marginally resected low-grade STS of the extremities (distal to the elbow or stifle) have been report-ed to be 11% overall7. In another study, recurrence rates were dependant on the grade of the marginally resected canine STS: 7% for grade 1, 24% for grade 2 and 75% for grade 3, although the number of grade 3 STS included in this study (n=4) was too low for this figure to be reliable8. No recurrences were observed when wide resection was performed, indicating that clean tumour margins were predictive for non-recurrence (n=30)8. Another study of



20

revision excision of incompletely excised STS on 41 dogs found recurrence and metastatic rates of 15% and 10%, respectively9. The presence of residual tumour was identi-fied in 22% of resected scar tissues and it did not appear to predict recurrence9. When marginal resection of STS of the limbs was intentional and followed by adjuvant radio-therapy (hypofractionated protocol, 4 x 8-9Gy), recurrence rates of 18% have been observed and the only factor pre-dicting recurrence appeared to be the delay between sur-gery and radiotherapy10.

In view of these studies, marginal resection of canine low-grade STS of the extremities may be considerable, ei-ther alone or combined with radiotherapy, when a wider excision is not easily possible. In this setting, the propor-tion of dogs dying of causes related to their STS varies between 10% and 33%2.

As stated above, advanced imaging is most valuable in planning surgery, as the main obstacles to achieving suffi-cient margins are the vicinity of non-expendable anatomi-cal structures (resection phase) and the ability to recon-struct the operated area (reconstruction phase).

When considering the resection phase, the targeted margins are planned from the 3-dimensional advanced images and any important anatomical structure located within them is considered. The benefit of achieving the sought margins should be balanced against the potential functional and cosmetic consequences of sacrificing these structures, and a decision can be made. When all tissues within the planned margins are considered expendable, the surgical excision is considered likely to be satisfactory. When not, the surgery will be unlikely to provide sufficient margins and adjuvant therapies should be considered.

The reconstruction phase is however often the most challenging part of the surgery of STS. In general, onco-logic surgery requires a solid knowledge of reconstruc-tive surgery, as limitations in the ability to reconstruct a wound should never lead to insufficiently wide resections. The greater the reconstruction abilities of the surgeon, the more comfortable they will be administering the appropri-ate dose of surgery in the face of a large or awkwardly located tumour.

RadiotherapyRadiotherapy can be used either alone or combined

with surgery for local disease control.

Used as the sole treatment, it is mainly palliative. Ra-diotherapy cannot cure macroscopically detectable sarco-mas, as these tumours are radioresistant. In this setting, “control” is therefore defined as regression or stabilisation of the tumour size. With radiotherapy as the sole treat-ment, control rates of STS have been reported to be 50% at 1 year and 33% at 2 years11, 12. A hypofractionated pro-tocol (4x8Gy) was associated with a 50% response rate, a median time to progression of the disease of 155 days (72-460 days) and a mean survival time of 309 days in a study of 16 dogs with STS11. Combination of radiation with hyperthermia increases the median duration of local

control (350 days for radiotherapy alone versus 750 days combined with hyperthermia)1.

Radiotherapy is best used as a combination with sur-gery, either in a neoadjuvant or adjuvant setting. It is also indicated when insufficient margins are achieved by sur-gery, and revision surgery is not possible or unlikely to be more successful13, 14. Control rates for adjuvant radiothera-py after incomplete excision of STS in dogs are reported to be 80-95% at 1 year and 72-91% at 2 years, with 3-year and 5-year survival rates of 76% and 68%1. Reported recurrence rates after revision surgery or adjuvant radio-therapy have been reported to be 15%9 and 17-31%13-15, respectively. Median survival times after revision surgery (1416 days16) are comparable to those after adjuvant radiotherapy (1851 days14). Adjuvant radiotherapy for in-completely excised STS has been reported to be associated with lower median survival times for oral tumours (540 days) than tumours of other sites (2270 days)14.

ChemotherapyMost STS are resistant to chemotherapy with response

rates typically being below 30%. Chemotherapy is there-fore not a good option as the primary treatment for STS.

On the other hand, the benefit of adjuvant chemo-therapy after complete excision of STS is unclear, except for non-typical STS having a moderate-to-high metastatic rate, such as haemangiosarcomas (grade II, III or viscer-al), histiocytic sarcomas, etc. Chemotherapy can also be considered for metastasised, high-grade or incompletely-excised STS. Protocols used for treatment of STS are based on a single agent (e.g. doxorubicin or mitoxantrone) or combinations of chemotherapeutic drugs including doxo-rubicin, vincristine and cyclophosphamide. Metronomic chemotherapy using piroxicam and low-dose doxorubicin seems to prolong the disease-free interval in dogs with incompletely excised STS17.

The role of neoadjuvant (primary) chemotherapy be-fore surgery for STS remains to be investigated in veteri-nary medicine.

ImmunotherapySeveral studies have investigated the effect of immu-

notherapy on recurrence rates of soft tissue sarcomas. Ad-ministration of interleukin 2 (IL-2) via viral vectors has been shown to decrease recurrence rates of spontaneous feline soft tissue sarcomas. Increases in the disease-free intervals and survival times have also been observed after intratu-moral administration of histocompatible cells expressing human IL-2.

Prognosis

The prognosis for STS is very variable and depends on the precise nature of the tumour. For typical STS, it is fair and the main obstacle to cure is local disease control. Re-currence rates after surgery, with or without radiotherapy, have been reported to be 7% to 32%. Prognostic factors for tumour recurrence include tumour grade, tumour size and incomplete surgical excision.



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The metastasic rate of STS is reported to be around 20%, and it is dependent on the tumour grade, ranging from 15% for grades 1 and 2, to 41% for grade 3 STS1. The metastases tend to be delayed and occur late in the course of the disease with a median time to development of metastatic disease of 365 days1.

Since the time to local recurrence and distant metas-tasis development can be long, it is important to follow the affected patients on the long-term. An example of recommended schedule would be to recheck the patient at 1,2,3,6,9 and 12 months after treatment, and twice a year thereafter.

Feline injection-site sarcomas

Feline injection-site sarcomas (FISS) include different types of tumours of similar clinical presentation and be-haviour, occurring in the location of a previous inflamma-tion (injection, insect bite wound, etc.). The pathogene-sis of these tumours is still poorly understood, but local growth factors and cellular mutations seem involved in the malignant transformation of fibroblast within the in-flammation. They are extremely locally invasive tumours which tend to metastasise infrequently (up to 26%18) and late in their course. However, as veterinarians’ ability to achieve local control of these tumours improve (better planned surgeries, adjuvant radiotherapy, chemotherapy), cats survive longer and it seems that metastases are more frequent a problem than originally reported. In any event, when metastatic disease is not detected at the time of diagnosis, these tumours are mainly a local problem for which an aggressive (wide) resection, whenever possible, is the treatment of choice. In cats, sarcomas developing in the location of an inflammation (“FISS”) tend to be more aggressive than other soft tissue sarcomas19. Practically, sarcomas occurring in areas of injections (vaccine or oth-ers) or in the location of an earlier trauma (bite, wound, etc.) must be treated aggressively (wide surgical excision and radiotherapy as possible).

SurgeryWhen to operate?

Any mass located in the location of an injection or inflammation, with clinical and cytological presentations compatible with a sarcoma must be excised widely. How to manage an inflammatory or post-injection reaction is more controversial. When does an inflammatory reaction become suspicious enough to be treated as a malignancy? Most authors base their approach on the guidelines of the Vaccine-Associated Feline Sarcoma Task Force (VAFSTF) which recommends to treat as FISS any inflammatory re-action persisting more than 3 months after an injection, measuring more than 2 cm or still increasing in size more than 1 month after the injection20.

How to plan surgery?Advanced imaging techniques (contrast-enhanced CT

and MRI) are essential to precisely determine the tumour invasion in 3 dimensions, which will dictate the extent of the required surgical excision. The external physical pres-entation of the tumour can be deceiving and the tumoral

volume as determined from a CT study was found to be twice as large as the volume estimated from direct physical measurement of the tumour21.

How to operate?Initially, it has been recommended to excise FISS with

a minimum of 2-cm lateral margins and one deep fascial plane. These recommendations are not sufficient and lead to complete excision of such tumours in less than 50% of cases22, 23, which results in high recurrence rates. A more aggressive surgery is associated with better results: in a study of 61 cases, the time to first recurrence was sig-nificantly shorter after marginal resection than after wide resection (66 versus 419 days)22. Similarly, cats operated by non-specialist veterinarians appeared to have earlier recurrences than those operated in a referral centre (66 versus 274 days)22. Whereas surgery as sole treatment is not currently the gold standard of FISS treatment (combin-ing surgery with radiotherapy and chemotherapy improve the prognosis24), it clearly appears that a more aggressive surgery is associated with a better outcome in terms of disease-free interval and survival times, whether the sur-gery be used alone or combined with other treatments. Some surgeons recommend excising FISS with 5-cm lateral margins and two deep fascial planes25. This more aggres-sive approach resulted in complete excision of the tumour in 97% of cases, leading to a recurrence rate of 11% and disease-free rates of 91%, 86% and 74% at 1, 2 and 3 years, respectively26. A larger retrospective study of this approach (91 cases) reported a recurrence and metastatic rates of 14% and 20% respectively27. Median survival times were 499 days for cats with tumour recurrence ver-sus 1461 days for cats without27. Median survival times were 388 days for cats which developed metastatic dis-ease and 1528 days for cats who did not27. The drawbacks of such an approach are the more challenging reconstruc-tions and the increased rate of wound dehiscence. In this latter study, 7 out of 91 cats (8%) had dehiscence of their surgical wound27.

The wide excision of FISS often involves extensive re-sections, frequently including bony resections (spinous processes, scapulae, etc.). Similarly, wound reconstruction can be technically challenging and necessitate placement of prostheses, such as meshes, and skin or myocutaneous flaps28.

These aggressive resections are very traumatic and in-duce severe pain. In addition to usual analgesia routes, the use of wound catheters is very efficacious. These cath-eters are commercially available, but can alternatively be designed from polyethylene tubing18. They are placed in the wound during surgery and are used postoperatively to instil local anaesthetics in the wound for several days after surgery. I routinely use these catheters after FISS resection. They subjectively are very helpful to control postoperative pain and make it possible to lower the doses and limit the side-effects of other analgesic drugs.

Radiotherapy

Ideally, as FISS have a high local recurrence rate in spite



22

of surgery, radiotherapy should always be associated to surgery in their treatment. Radiotherapy can be neoad-juvant or adjuvant. With FISS, neoadjuvant radiotherapy may be of particular interest, although studies have failed to show a significant improvement in local tumour control in this setting29, 30. When radiotherapy is combined with surgery, mean survival times of 600 to 1300 days have been reported, with 1-, 2- and 3-year survival rates of 86%, 44-71% and 28-68%, respectively.

Radiotherapy alone is only palliative but can be consid-ered for inoperable tumours.

Chemotherapy

For the moment, chemotherapy seems to be of lim-ited benefit in the treatment of FISS. In a study of 76 cats with FISS treated with surgery and radiotherapy, with or without chemotherapy, the latter made no difference in recurrence rates, metastatic rates and survival times (Co-hen JAVMA 2001). Responses have been reported with doxorubicin, either alone or combined, but these lasted only a few months31, 32. However, in cats responding to chemotherapy it appeared to prolong survival, including for incompletely excised tumours also treated with radio-therapy33.

References

1. Liptak JM, Forrest LJ. Soft tissue sarcomas. In: Withrow SJ, Vail DM, Page RL (eds): Withrow & MacEwen’s small animal clinical oncology, 2013;356-380.

2. Ryan S, Wouters EGH, Van Nimwegen S, Kirpensteijn J. Skin and subcutaneous tumors. In: Kudnig ST, Séguin B (eds): Veterinary surgical oncology. Oxford: Wiley-Blackwell, 2012;55-85.

3. Baker-Gabb M, Hunt GB, France MP. Soft tissue sarcomas and mast cell tumours in dogs; clinical behaviour and response to surgery. Aust Vet J. 2003;81: 732-738.

4. Yoon J, Feeney DA, Cronk DE, Anderson KL, Ziegler LE. Computed tomographic evaluation of canine and feline mediastinal masses in 14 patients. Veterinary Radiology & Ultrasound. 2004;45: 542-546.

5. Bray JP, Polton GA, McSporran KD, Bridges J, Whitbread TM. Canine soft tissue sarcoma managed in first opinion practice: outcome in 350 cases. Veterinary Surgery. 2014;43: 774-782.

6. Chase D, Bray J, Ide A, Polton G. Outcome following removal of canine spindle cell tumours in first opinion practice: 104 cases. Journal of Small Animal Practice. 2009;50: 568-574.

7. Stefanello D, Morello E, Roccabianca P, Iussich S, Nassuato C, Martano M, et al. Marginal excision of low-grade spindle cell sarcoma of canine extremities: 35 dogs (1996-2006). Veterinary Surgery. 2008;37: 461-465.

8. McSporran KD. Histologic Grade Predicts Recurrence for Marginally Excised Canine Subcutaneous Soft Tissue Sarcomas. Veterinary Pathology Online. 2009;46: 928-933.

9. Bacon NJ, Dernell WS, Ehrhart N, Powers BE, Withrow SJ. Evaluation of primary re-excision after recent inadequate resection of soft tissue sarcomas in dogs: 41 cases (1999–2004). Journal of the American Veterinary Medical Association. 2007;230: 548-554.

10. Demetriou JL, Brearley MJ, Constantino-Casas F, Addington C, Dobson J. Intentional marginal excision of canine limb soft tissue sarcomas followed by radiotherapy. Journal of Small Animal Practice. 2012;53: 174-181.

11. Lawrence J, Forrest L, Adams W, Vail D, Thamm D. Four-fraction radiation therapy for macroscopic soft tissue sarcomas in 16 dogs. Journal of the American Animal Hospital Association. 2008;44: 100-108.

12. McChesney SL, Withrow SJ, Gillette EL, Powers BE, Dewhirst MW. Radiotherapy of soft tissue sarcomas in dogs. Journal of the American Veterinary Medical Association. 1989;194: 60-63.

13. McKnight JA, Mauldin GN, McEntee MC, Meleo KA, Patnaik AK. Radiation treatment for incompletely resected soft-tissue sarcomas in dogs. Journal of the American Veterinary Medical Association. 2000;217: 205-210.

14. Forrest LJ, Chun R, Adams WM, Cooley AJ, Vail DM. Postoperative radiotherapy for canine soft tissue sarcoma. Journal of Veterinary Internal Medicine. 2000;14: 578-582.

15. Simon D, Ruslander DM, Rassnick KM, Wood CA, Frimberger AE, Cotter SM, et al. Orthovoltage radiation and weekly low dose of doxorubicin for the treatment of incompletely excised soft-tissue sarcomas in 39 dogs. Veterinary Record. 2007;160: 321-326.

16. Kuntz CA, Dernell WS, Powers BE, Devitt C, Straw RC, Withrow SJ. Prognostic factors for surgical treatment of soft-tissue sarcomas in dogs: 75 cases (1986-1996). Journal of the American Veterinary Medical Association. 1997;211: 1147-1151.

17. Elmslie RE, Glawe P, Dow SW. Metronomic therapy with cyclophosphamide and piroxicam effectively delays tumor recurrence in dogs with incompletely resected soft tissue sarcomas. Journal of Veterinary Internal Medicine. 2008;22: 1373-1379.

18. Davis KM, Hardie EM, Lascelles BDX, Hansen B. Feline fibrosarcoma: perioperative management. Compendium Continuing Education for Veterinarian. 2007;29: 712-729.

19. Hauck M. Feline injection site sarcomas. Veterinary Clinics of North America, Small Animal Practice. 2003;33: 553-571.

20. Morrison WB, Starr RM. Vaccine-associated feline sarcomas. Journal of the American Veterinary Medical Association. 2001;218: 697-702.

21. McEntee MC, Page RL. Feline vaccine-associated sarcomas. Journal of Veterinary Internal Medicine. 2001;15: 176-182.

22. Hershey AE, Sorenmo KU, Hendrick MJ, Shofer FS, Vail DM. Prognosis for presumed feline vaccine-associated sarcoma after excision: 61 cases (1986-1996). Journal of the American Veterinary Medical Association. 2000;216: 58-61.

23. Davidson EB, Gregory CR, Kass PH. Surgical excision of soft tissue fibrosarcomas in cats. Veterinary Surgery. 1997;26: 265-269.

24. Séguin B. Feline injection site sarcomas. Veterinary Clinics of North America, Small Animal Practice. 2002;32: 983-995.

25. Kuntz CA. Modified wide local excision for vaccine associated soft tissue sarcomas in cats (abstract). Veterinary Surgery. 2000;29.

26. Liptak JM, Forrest LJ. Soft tissue sarcomas. In: Withrow SJ, Vail DM (eds): Withrow & MacEwen’s small animal clinical oncology. St. Louis, Mo.: Saunders Elsevier, 2007;425-454.

27. Phelps HA, Kuntz CA, Milner RJ, Powers BE, Bacon NJ. Radical excision with five-centimeter margins for treatment of feline injection-site sarcomas: 91 cases (1998-2002). Journal of the American Veterinary Medical Association. 2011;239: 97-106.



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28. Lidbetter DA, Williams FA, Jr., Krahwinkel DJ, Adams WH. Radical lateral body-wall resection for fibrosarcoma with reconstruction using polypropylene mesh and a caudal superficial epigastric axial pattern flap: a prospective clinical study of the technique and results in 6 cats. Veterinary Surgery. 2002;31: 57-64.

29. Kobayashi T, Hauck ML, Dodge R, Page RL, Price GS, Williams LE, et al. Preoperative radiotherapy for vaccine associated sarcoma in 92 cats. Veterinary Radiology & Ultrasound. 2002;43: 473-479.

30. Cronin K, Page RL, Spodnick G, Dodge R, Hardie EN, Price GS, et al. Radiation therapy and surgery for fibrosarcoma in 33 cats. Veterinary Radiology & Ultrasound. 1998;39: 51-56.

31. Poirier VJ, Thamm DH, Kurzman ID, Jeglum KA, Chun R, Obradovich JE, et al. Liposome-encapsulated doxorubicin (Doxil) and doxorubicin in the treatment of vaccine-associated sarcoma in cats. Journal of Veterinary Internal Medicine. 2002;16: 726-731.

32. Barber LG, Sørenmo KU, Cronin KL, Shofer FS. Combined doxorubicin and cyclophosphamide chemotherapy for nonresectable feline fibrosarcoma. Journal of the American Animal Hospital Association. 2000;36: 416-421.

33. Eckstein C, Guscetti F, Roos M, Martín de las Mulas J, Kaser-Hotz B, Bley CR. A retrospective analysis of radiation therapy for the treatment of feline vaccine-associated sarcoma. Veterinary and Comparative Oncology. 2009;7: 54-68.



24

TUMOURS OF THE BODY WALL

Laurent Findji

In oncologic surgery, full-thickness resections of por-tions of the abdominal and thoracic walls are not un-common. They may be required for treatment of primary tumours of the body wall (e.g. rib tumours) or to obtain sufficient margins when resecting tumours of nearby tis-sues (e.g. soft tissue sarcomas, pulmonary or mediastinal tumours).

Tumour types

Tumours most frequently requiring thoracic wall resec-tions are rib osteosarcomas (OSA) and chondrosarcomas (CSA), as well as tumours of soft tissues of the thoracic wall itself or of tissues in its vicinity, such as soft tissue sarcomas.

Diagnosis

The diagnosis of body wall tumours often starts by the detection of a subcutaneous mass over the trunk. The ex-ternal aspect of these tumours can be deceiving and ad-vanced imaging (CT scanning or MRI) is essential to plan their potential surgical resection. The origin of the tumour, from which the tissue planes to resect can be decided, and its intracavitary extension can be determined from ad-vanced imaging. Conventional radiography can also show invasion of body cavities by the tumour, especially for the thoracic cavity, but with lesser sensitivity and reliability.

Preoperative biopies are essential. Fine-needle aspi-rates are often insufficient to obtain a reliable diagnosis of the tumoral type and, in any case, cannot provide grading of the tumour. Incisional biopsies can be performed with a core-needle or surgically (e.g. wedge biopsies). Surgical biopsies are more reliable because of their larger size1. As per general rules of oncologic surgery, it is crucial not to jeopardise the potential subsequent surgical resection and the fact that the biopsy tract will require to be excised en-bloc with the tumour needs to be carefully anticipated.

Treatment

SurgeryIdeally, surgery must be planned from advanced imag-

ing studies. When resecting rib tumours, the excision must include at least one rib cranially and one rib caudally to the affected rib and, in the dorsoventral direction, margins of at least 3 cm are generally recommended. This recom-mendation is obviously not rigid and the required margins depend on the tumour type and size. In addition, a com-partmental resection of the affected rib (i.e. resecting the entire rib) can be preferable for locally aggressive tumours (e.g. OSA).

For tumours infiltrating or in the vicinity of the thoracic wall, the number of ribs to resect is determined from the findings of advanced imaging and the determined tumour type and grade. It is widely accepted that up to 6 ribs can safely be resected without any rigid reconstruction of the chest wall. Resecting 7 ribs has however been reported2 and is considered feasible by surgical oncologists. Con-versely, it seems that resecting 8 ribs or more is more likely to result in significant functional impairment of the tho-racic wall and is not recommended.

When resecting tumours originating from the tho-racic (ribs, intercostal muscles) and abdominal (transverse, oblique or rectus abdominis muscles) walls, the number of tissue layers external (superficial) to the tumour is suf-ficient to make wide resection of the skin unnecessary. Therefore, except for any biopsy tracts, a linear or curvi-linear incision of the skin and cutaneous trunci muscle is appropriate. When a biopsy tract is present, it must ex-cised en-bloc with the tumour with at least 2 to 3 cm of lateral margins. This general rule is obviously not absolute and the necessity to resect portions of skin is best judged on the extension of the tumour as evaluated on advanced imaging, as well as from the subjective assessment of the adherence of the skin and subcutaneous tissues to the un-derlying tumour.

Conversely, when resecting more superficial tumours, wide resection of the skin, en-bloc with the rest of the excision, is most often indicated.

For thoracic wall resections, depending on tumour ex-tension, the latissimus dorsi muscle is either partially re-sected along the lines of the underlying costal resection or reclined dorsally if it can be spared2. Again, determining




25

whether the latissimus dorsi muscle can be spared or must be resected is best done by assessing the number of tissue planes between it and the tumour from advanced imaging studies.

Thoracic wall resections generally starts with an in-tercostal thoracotomy at the cranial or caudal boundary of the planned resection. The safest thoracotomy site, in terms of margins, must be chosen on the base of ad-vanced imaging. This thoracotomy allows verification of the macroscopic intrathoracic extension of the tumour, to ascertain that it is not greater than assessed on advanced imaging. Ribs are then sectioned with an oscillating saw or rib shears, along the line of the ventral or dorsal bound-ary of the planned resection. Between each rib section, the intercostal muscles are cut and the intercostal artery and vein are cauterised with uni- or bipolar electrocautery. Once this ventral or dorsal section has been carried out, the costal flap can be slightly elevated to assess once more the macroscopic extension of the tumour and verify that the next planned section line is appropriate. The next sec-tion line is then performed (ventral/dorsal or caudal/cra-nial) and, once more, the tumour position and extension is checked by elevating the costal flap further. The remaining section line is then performed and the costal flap is freed. It is lifted gently and the presence of any adhesions of the flap/tumour with intrathoracic structures (diaphragm, lungs) is evaluated. When the tumour is adherent to the diaphragm, the latter is partially resected with a minimum a 2 to 3 cm margins, en-bloc with the tumour and chest wall. When the tumour is adherent to a lung lobe, a partial or complete lung lobectomy. If a complete lung lobectomy is chosen, it is most easily performed with a stapler (e.g. TA stapler) as the pulmonary hilus may be quite remote from a rather caudal costal flap and therefore be difficult to reach. Occasionally, adhesions of the tumour with the pericardium necessitate to perform a partial pericardec-tomy. In all such cases, adhesions between the tumour and intrathoracic structures are not detached to avoid dis-semination of tumour cells in the surgical field and chest. The adhered organ is partially resected en-bloc with the tumour whenever possible.

A chest drain is then placed under direct visual control and intercostal nerve blocks are performed on resected rib spaces and 2 to 3 spaces cranially and caudally to them.

The chest wall is then reconstructed. Several tech-niques are available to restore the functional capacity of the rib cage. When the wall resection involved caudal ribs and the diaphragm needed to be disinserted, it can be attached to the remaining dorsal portion of the sectioned ribs and along the rib immediately cranial to the thoracic wall defect. This technique is referred to as diaphragmatic advancement. Once the diaphragm is advanced, the tho-racic cavity is reconstituted and closed, but of a smaller volume than previously. The body wall defects then be-comes an abdominal well defect. When the diaphragm is markedly advanced, the diminution in the volume of the thoracic cavity can be physiologically significant and cause ventilation-perfusion mismatches in the lung on the oper-ated side, which cannot fully expand. Therefore, when the

diaphragmatic advancement results in a great reduction of the thoracic volume, raising concerns about the expansion of the ipsilateral lung, it can be preferable to perform a caudal lung lobectomy to prevent any postoperative res-piratory complications.

The reconstruction of body wall defects must use au-tologous tissues as often and as much as possible to re-duce the risk of postoperative complications3. The utilisa-tion of synthetic meshes only to reconstruct defects in the thoracic wall was associated with 12.8 times more compli-cations and the combined use of meshes and autologous tissues with 3 times more complications, both compared with the exclusive use of autologous tissues3. In many cas-es, a muscle flap using the latissimus dorsi can be used to cover thoracic wall defects. To perform such a flap, the cranioventral insertion of the muscle on the humerus is left intact and its caudodorsal insertion is on the lumbar fascia is sectioned as caudally and as dorsally as possible to elevate the muscle, which is then transposed and sutured to the edges of the thoracic wall defect, thereby covering it. Other muscle flaps, using nearby muscles such as pecto-rals, or lumbar fascia grafts can also be used to cover the parietal defect. Lastly, when all sources of autologous tis-sues are insufficient to entirely cover the body wall defect, synthetic implants such as meshes, either non-absorbable (e.g. polypropylene) or absorbable (e.g. polydioxanone), can be used. Ideally, intracavitary organs should be pre-vented to come into contact with the mesh by interposing autologous tissues. The greater omentum is most com-monly used for this purpose. It is easily transposed and brought to the parietal defect, directly for abdominal wall defects and either through a retrocostal or transdiaphrag-matic approach for thoracic wall defects.

The addition of rigid implants such a

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