854 C O R R E S P O N D E N C E

Letter 2

Sir The article by Mr Rosario and colleagues (Br J Surg 1994; 81: 897) highlights the problems and morbidity of iliohypogastric and ilioinguinal nerve blockade for anaesthetizing the inguinal region. The technique which is recommended by the Royal College of Surgeons of England’ is unreliable and, because of the uncertainty of anaesthetizing the ilioinguinal nerve, large volumes of local anaesthetic tend to be introduced into the area resulting in unwanted femoral nerve paresis.

Having used local anaesthesia with conscious sedation for hernia repair over many years, I find the simplest and most effective technique is surgeon-administered using the direct local infiltration ‘as you go’ method. It is applicable for any open repair.

A reassuring preoperative explanation of the procedure to the patient, followed by conscious sedation, prepares the patient for the injections which should no longer be a ‘grit the teeth’ or ‘white knuckle’ experience. After pre-emptive analgesia (diclofenac suppository) and intravenous sedation (usually minimal doses of diazepam and pethidine tailored to the patient’s response) the patient is ready for local anaesthesia. The line of incision is marked with a ‘Pentel’ pen so that it does not rub off with preparation of the skin. The local anaesthetic is infiltrated subcutaneously under the line, which is a guide for the incision. Once through the skin, further infiltration is made deep to Scarpa’s fascia which is then incised exposing the external oblique fascia. The local anaesthetic is then introduced deep to the external oblique to distend the inguinal canal. After entering the inguinal canal, further local anaesthetic infiltration is made around the internal ring, into the internal oblique and transversalis fascia. The cord is mobilized. If an indirect hernia is being dealt with, local infiltration is made into the cord at the level of the internal ring. Small indirect sacs are dissected free and excised after transfixing the neck. Large scrota1 sacs are transected at the neck and the distal part is left; sliding hernias are dissected free and pushed back into the abdominal cavity, and a few stitches to narrow the internal ring are inserted to prevent extrusion. If the hernia is direct, it is inverted and plicated. The normal anatomy is thus restored in preparation for an onlay mesh repair, which I prefer as it reinforces the conjoint area and internal ring.

I use a mixture of 40 ml lignocaine 0.5 per cent with 11200 000 adrenaline (2 bottles) and 10ml bupivacaine 0.5 per cent with 1/200000 adrenaline (1 ampoule), as they are standard preparations. For a single hernia repair I aim to use about 30 ml. For a double hernia, the local anaesthetic is diluted with an equal amount of saline to an 0.25 per cent concentration. If I need larger volumes, further dilutions to 0.125 per cent are just as effective. With recurrent hernia repairs, the dilute solution allows greater volumes to be injected deep to the external oblique; this assists in identifying the structures of the cord by fluid dissection.

Having used this technique over 30 years for hernia repair, I have yet to encounter a femoral nerve paresis or other side- effects.

M. J. Notaras 11/20 Harley Street London WIN 1AA UK

1 Clinical Guidelines on the Management of Groin Hernia in Adults. Report of a working party convened by the Royal College of Surgeons of England, July 1993.

Delayed diagnosis of malignant tumours missed at laparoscopic cholecystectomy

Sir We were interested to read the Case Report by Mr Sharp and colleagues (Br J Surg 1994; 81: 1650) on two cases of malignant

tumours of the right colon and the pancreas recognized 10 months after laparoscopic cholecystectomy.

We were faced with this serious problem recently. Among 885 patients who underwent laparoscopic cholecystectomy at our surgical unit, five (03 per cent) were reoperated for missed tumours of the right colon (a = 3) and the pancreas (n = 2). Two further patients with tumours of the right colon and pancreas had a history of laparoscopic cholecystectomy performed elsewhere. The median (range) age of the seven patients was 72 (66-76) years, and all patients complained of recent atypical abdominal pain. Only five tumours were resected (including two palliative resections) and two patients died after operation. The median (range) diagnostic delay was 11 (2-28) months.

The demand for laparoscopic cholecystectomy from patients and practitioners is becoming increasingly frequent, who are both aware of its benefits. In this way, in one American register’ the total cholecystectomy rate increased almost 60 per cent after the introduction of laparoscopic cholecystectomy. In fact, the recommendations of the National Institutes of Health2 and these cases of missed tumours remind us that a positive ultra- sonography does not avoid a careful semiological analysis of the pain characteristics and associated symptoms. None of our patients had typical biliary pain, and the retrospective analysis of associated symptoms revealed recent constipation in all cases of colonic tumours.

The main malignant diseases that can be missed at laparoscopic cholecystectomy in our study (as in the cases reported by Mr Sharp and colleagues) are tumours of the right colon and the pancreas. The prognosis was poor in most cases. Even if we cannot state that earlier diagnosis would improve the prognosis, the diagnostic delay due to unnecessary laparoscopic cholecystectomy is a cause of major concern.

Service de Chirurgie Digestive Hotel Dieu, BP 69 63003 Clermont-Ferand Cedex France

K. Slim

1 Legoretta AP, Silber JH, Costantino GN, Kobylinski RW, Zatz SL. Increased cholecystectomy rate after the introduction of laparoscopic cholecystectomy. J A M 1993; 270: 1429-32.

2 NIH Consensus Development Panel on Gallstones and Laparoscopic Cholecystectomy. JAM 1993; 269: 1018-24.

Virtual reality and laparoscopic surgery

Sir I am impressed by the Review by Mr Coleman and colleagues (Br J Surg 1994; 81: 1709-11) and I, too, consider it a ‘virtual certainty’ that this new science will find a place in surgical endeavour.

However, may I make a plea for care in the use of the word ‘virtual’ as this word will become more and more associated with leisure pursuits and, anyway, there is nothing ‘virtual’ about surgery. It may already be too late to abandon it altogether but, at least, we should differentiate between conceived and actual operations. Virtual reality may have some useful meaning when applied to surgical simulation but it is totally inappropriate in the context of genuine surgery. Telepresence and telesurgery are better but even these suggest an element of ‘unreality’ about the procedures. I hope someone will coin a more fitting phrase soon because this is the only chance, at the introduction of this new surgical science (and surgical art), to correct potential errors in communication. After all, what would the Clapham omnibus passenger think if he or she was asked to sign a consent form for ‘virtual surgery’, by virtual surgeons using virtual instruments in a virtual operating theatre perhaps?

There is another potential trap for the unwary. There is a great difference between surgery using truly remote control and surgery using robotics and telepresence technology but with ‘hands on’ the actual instruments inserted into the abdomen.

British Journal of Surgery 1995, 82,852-858

C O R R E S P O N D E N C E 855

Indeed, I fail to understand why anyone would wish to operate ‘even from the other side of the world’. I can perhaps appreciate why it would be useful to observe an operation from distant centres - for training or even to obtain expert guidance - but there seems no good reason for a surgeon to operate (or a patient to wish to be operated upon) by remote control! Even the situation on the battlefield or in inaccessible sites such as parts of Australia and Antarctica do not seem apposite because, after all, the patient has to be anaesthetized, the instruments correctly placed and all the technology monitored; if personnel are available for all these procedures in distant sites why not a trained operating technician at least capable of controlling life- threatening conditions? Perhaps, let us agree, with the help of a television link to a major centre.

A word now about computer simulation. I, too, have seen the Virtual Clinic (Cint-Med, Woodbury, Connecticut, USA) and I cannot agree that ‘the system is amazingly realistic’; what is being achieved is amazing but I fear there is a long way to go before the present ‘virtual realism’ becomes even remotely realistic. Nevertheless I, like Mr Coleman and colleagues, know that the problems they summarize so well will be overcome and we can look forward to the day when these new sciences of robotics and computer assistance will provide us with sophisticated surgical instruments for every day use in training and in the operating theatre.

M. H. Ornstein 136 Harley Street London WIN 1AH UK

Inflammatory mediators in acute pancreatitis

Sir We read with interest the Review by Dr Formela and colleagues (Br J Surg 1995; 82: 6-13). As they rightly point out, neutrophil activation is an early feature of acute lung injury and the related multiple organ dysfunction syndrome, both of which complicate severe acute pancreatitis. However, with the recently reported method’ of assay for group 1 (pancreatic) phospholipase A2 (PLA2), we would disagree that the assay of this marker plays no useful role in the early prediction of disease severity. The precise role of PLA2 has become obscured because of the inherent constraints of catalytic and immunoassays for the measurement of the parent enzyme. Catalytic assays are unable with confidence to differentiate between group 1 and group 2 (synovial) PLA2. Similarly, immunoassays cannot differentiate between catalytically active, and bound, inactive species of PLA2.

Group 1 PLA2 is biosynthesized and stored as an inactive zymogen. On activation, there is limited tryptic-like proteolysis at the N-terminus of the mature species with the equimolar release of a species-specific activation peptide. In humans this oligopeptide has the sequence DSGISPR (single letter amino acid code). By raising antibodies to the carboxy-terminus of synthetic DSGISPR, a sensitive and specific enzyme linked immunosorbent assay has been developed which confidently reports the presence of a single activated gene product’. Using this assay, the release of group 1 PLA2 from the trypsinized lysates of human neutrophils, but not human macrophages or lymphocytes, was demonstrated. Also demonstrated was the release of group 1 PLA2 following exposure of human neutrophils to 1 pmoM human tumour necrosis factor alpha, interleukin 1 alpha and granulocyte-macrophage colony stimulating factor’.

In a prospective study of 50 patients, the presence of plasma DSGISPR on admission to the study had a sensitivity of 100 per cent and a specificity of 95 per cent for the presence or future development of acute lung injury or multiple organ dysfunction syndrome, including that caused by acute pancreatitis2.

We would suggest that the demonstration of a close association between a cellular and biochemical effector of tissue injury may be of importance. The reliable identification of a specific group of PLA2 may contribute to the precise definition of the role of this enzyme in the evolution of the systemic complications of severe acute pancreatitis, and its assay could provide a useful early predictive marker.

D. Rae R. C. Bowyer

R. Q. Wharton Department of Surgev Frimley Park Hospital Frimley Surrey GU16 5UJ UK

Rae D, Sumar N, Beechey-Newman N, Gudgeon M, Hermon-Taylor J. Type 1 prophospholipase A2 propeptide immunoreactivity is released from activated granulocytes. Clin Biochem 1995; 28: 71-8. Rae D, Porter J, Beechey-Newman N, Sumar N, Bennett D, Hermon-Taylor J. Type 1 prophospholipase A2 propeptide in acute lung injury. Lancet 1994; 344: 1472-3.

Duplex ultrasonography for assessment of venous valvular function of the lower limb

Sir There is evidence that, for symptomless individuals, reverse flow in deep leg veins rarely lasts more than 0.5 s. To our knowledge, none of the published research on this subject has studied patients with proven normal deep venous function. The paper by Mr Sarin and colleagues (Br J Surg 1994; 81: 1591-5) confirms previous studies on clinically assessed patients. The paper concludes that ‘significant reflux is defined as reversed flow exceeding 0.5 s’, taking into account neither the vein scanned nor the position of the subject.

We have previously demonstrated reverse flow in deep veins lasting longer than 0.5 s following a valsalva manoeuvre in eight of 17 subjects who had proven normal deep veins on foot volumetry and ascending phlebography2. We have presented work at the North American Society of Phlebology which demonstrates that deep vein reverse flow may last more than 0.5 s in individuals with proven normal deep venous function. This work is at present submitted for publication and demonstrates that reversed flow lasting more than 0.5s as an indicator of deep venous reflux is of use only in the posterior tibia1 vein of the standing patient.

We remain concerned that the demonstration of reverse flow lasting more than 0.5 s in any deep vein is considered the sole indicator of significant deep venous disease. The definition used by Mr Sarin and colleagues would encompass many individuals with normally functioning deep veins.

N. R. F. Lagattolla K. G. Burnand

Department of Surgery St Thomas’ Hospital Lambeth Palace Road London SEI 7EH UK

1 Van Bemmelen PS, Bedford G, Beach K, Strandness DE. Quantitative segmental evaluation of venous valvular reflux with duplex ultrasound scanning. J Vasc Surg 1989; 10: 425-31.

2 Baker SR, Burnand KG, Sommerville KM, Lea Thomas M, Wilson NM, Browse NL. Comparison of venous reflux assessed by duplex scanning and descending phlebography in chronic venous disease. Lancet 1992; 341: 400-3.

British Journal of Surgery 1995, 82,852-858