ORIGINALCONTRIBUTION

Day-Case Karydakis Flap for PilonidalSinusJohn H. Anderson, M.D., � Christina O. Yip, M.B.Ch.B., �

J. S. Nagabhushan, M.S., � Sheila J. Connelly, S.E.N.,

Department of Coloproctology, Glasgow Royal Infirmary, Glasgow, United Kingdom

PURPOSE: The Karydakis flap for pilonidal sinus isassociated with primary wound healing and infrequentrecurrence. Previous studies had reported in-patientprotocols. This cohort study was designed to assess thefeasibility, safety, and practicalities of day-case Karydakisflap surgery. Factors relating to wound healing also wereexplored.

METHODS: Consecutive patients undergoing day-caseKarydakis flap surgery, by one consultant surgeon, forpilonidal sinus were studied prospectively. Patients wereassessed at weekly intervals after surgery until healing wascomplete. Wound healing time was compared with 1)patients’ gender, age, body mass index, deprivation index,occupation and smoking status, 2) pilonidal diseases’dimensions and proximity to anus, 3) wounds’ dimen-sions and proximity to anus, and 4) drain volume.

RESULTS: Day-case Karydakis flap surgery was feasible,safe, and effective. None of the 51 patients in the studyrequired readmission to hospital, sepsis drainage, orsurgery for recurrent sinus. Median wound healing timewas three weeks. Smokers healed quicker than nonsmo-kers. No other factors were identified that were associatedwith delayed healing. Normal activity was resumed withinone month of surgery in 95 percent of patients.

CONCLUSIONS: The Karydakis flap can offer the advantageof day-case surgery for pilonidal sinus patients in additionto primary wound healing and low sinus recurrence rates.

KEY WORDS: Pilonidal sinus; Karydakis;Ambulatory surgery.

P ilonidal sinus is a common condition that predomi-nately affects young adults who may be in full-time

education or employment.1 After sinus excision, asym-metric natal cleft wound closure can reduce the incidenceof delayed wound healing and sinus recurrence.2,3 Onesuch method, the Karydakis flap operation, flattens thenatal cleft and lateralizes the wound, resulting in primary

healing rates of more than 90 percent and sinus recur-rence rates of less than 5 percent.4,5

A MEDLINE search, using the term “Karydakis,” re-vealed six series of the Karydakis flap.4–9 These studies’reference lists disclosed two further articles.10,11 Thecombined published experience included 6,981 patients(6,545 of whom were in Karydakis’ personal series).However, all of these studies reported an in-patientprotocol, with mean admission duration ranging fromtwo to seven days. Clearly, day-case treatment of pilonidalsinus would be less expensive than in-patient care.12 Wedecided to attempt day-case Karydakis flap surgery becauseBascom’s “cleft lift” procedure, which also achieves pri-mary closure of a lateralized wound, has been reportedwith less than 24-hour hospitalization.13

It is recognized that young, hirsute, obese males, insedentary occupations, are susceptible to developing pilo-nidal sinus.4,14 However, it is not clear why some patientswith pilonidal sinus experience a poor outcome aftersurgery. Previous work has emphasized the impact ofsurgical technique on the risk of delayed healing and sinusrecurrence.3,13 To date, the concept that patient-relatedfactors may also influence outcome after pilonidal sinussurgery has received little attention.

The principal purpose of the present study was toassess the feasibility, safety, and practicalities of day-caseKarydakis flap surgery. Factors that might impair woundhealing also were examined.

PATIENTS AND METHODS

Consecutive patients undergoing day-case Karydakis flapsurgery for pilonidal sinus entered the study. All patientsgave informed consent. Surgery was undertaken by oneconsultant surgeon, utilizing general anesthesia, with thepatient in the prone position and the buttocks taped apartas previously described.5 A single dose of prophylacticantibiotics (1 g ceftriaxone and 500 mgmetronidazole) wasadministered intravenously at induction of anesthesia.

A line was drawn 2 cm paramedian to the natal cleft;this line was placed on the same side as any lateralsecondary opening or scar. The pilonidal cavity was probedand its longitudinal and lateral limits were marked. Usingthe initial paramedian line as its longitudinal axis, an ellipsewas drawn that included the entire pilonidal cavity. Thecaudal tip of the ellipse was placed a further 1 cm laterally

Presented at The Association of Coloproctology of Great Britain andIreland, Glasgow, United Kingdom, July 2 to 5, 2007.

Address of Correspondence: John H. Anderson, M.D., Department ofColoproctology, Glasgow Royal Infirmary, 16 Alexandra Parade, GlasgowG31 2ER, United Kingdom. E-mail: j.h.anderson@clinmed.gla.ac.uk

DOI: 10.1007/s10350-007-9150-y � VOLUME 51: 134–138 (2008) � ©THE ASCRS. 2007134

(i.e., 3 cm lateral to the midline) to avoid the final woundcurving toward the anus. The edge of the ellipse wasinfiltrated with 20 ml of 1 percent lidocaine hydrochloridewith adrenaline 1 in 200,000. The medial edge of the ellipsewas incised with a scalpel perpendicular to the skin anddown to, but not through, the thoracolumbar fasciaoverlying the sacrum. The ellipse’s lateral border was in-cised at an angle of 45° to the skin to meet the medialincision, thus removing the ellipse of tissue. The specimenwas inspected to ensure complete excision of the sinuscomplex and then it was weighed and sent for histologicexamination.

Hemostasis was secured with spray coagulating diather-my. A 10-French gauge suction drain was brought out lateralto the wound. A 1-cm thick, 2-cm wide flap was mobilizedwith cutting diathermy along the entire medial edge of thewound. In patients whose disease was close to the anus,particular care was taken to avoid trauma to the sphincters.Interrupted 2.0 Polysorb™ (Syneture™, Norwalk, CT) su-tures were placed at 1-cm intervals between the deep limitof the medial flap and the longitudinal midline of thebase of the elliptical cavity; the buttock tapes were releasedand the sutures tied. A second layer of interrupted 2.0Polysorb was placed at 1-cm intervals between the free edgeof the medial flap and the lateral aspect of the wound. Theskin was closed with subcuticular 3.0 Biosyn™ (Syneture™)then Leukostrips™ (Smith and Nephew, Hull, UK) andMepore® dressing (Mölnlycke Health Care, Dunstable, UK)was applied.

Postoperative pain, on a scale of 0 (none) to 10 (worstimaginable), was documented by the day-ward’s nurses.Patients were discharged four hours after surgery. The drainwas removed before discharge and its contents were mea-sured. A standard analgesic pack of Co-dydramol (2 tablets6-hourly) and Diclofenac (50 mg 8-hourly) was provided.

An experienced nurse, who was independent fromthe surgical team, undertook postoperative assessment atweekly intervals in the outpatient clinic and recorded pain,analgesic use, physical activity (mobility, lifting, dressing,bathing, and return to employment or education), andwound status. All wound discharges were swabbed forbacteriologic culture. A wound was defined as healed whenit was dry and had no skin separation, erythema, or bruis-ing. Wounds were recorded as healed by primary intentionif no skin separation was observed. Patients were dis-charged once healing was complete and they had returnedto normal activity.

Univariate analyses were undertaken to comparewound healing time vs. the variables: 1) patients’ gender,age, body mass index (BMI), deprivation category, occupa-tion, and smoking status, 2) pilonidal diseases’ length,weight, and proximity to anus, 3) wounds’ dimensions andproximity to anus, and 4) drain volume. This was performedby using the Kaplan-Meier method and the log-rank test(SPSS Inc., Chicago, IL).

Deprivation category or “DEPCAT” scores are de-rived for Scottish postcode areas from measurements ofunemployment, car ownership, overcrowded housing,and head of household’s social class and reported on ascale of 1 (most affluent) to 7 (most deprived).15

RESULTS

The study accrued 51 consecutive patients undergoingday-case Karydakis flap between October 2004 andOctober 2006. Median age was 24 (range, 16–46) years,and there were 41 male patients. Patients’ median BMIwas 28 (range, 21–33). Twenty-seven patients smoked.Three patients were in full-time education, 39 were em-ployed (22 manual and 17 nonmanual), and 9 were un-employed. The patients’ DEPCAT scores were: 1–2, 1patient; 3–4, 16 patients; and 5–7, 34 patients. Nineteenpatients had undergone previous pilonidal surgery; 17 ofthese had had an abscess drained and 2 patients hadundergone Bascom’s procedure. The median number ofmidline pilonidal pits and lateral secondary openings were2 (range, 0–6) and 1 (range, 0–2), respectively. Themedian length of the pilonidal subcutaneous cavity was3 (range, 1–12) cm and the caudal end of the cavity was amedian 7 (range, 1–11) cm from the anal verge. Allpatients had hair identified in the subcutaneous cavity.During the study period, a further two patients under-went inpatient Karydakis flap because of suboptimaldomestic circumstances, and no pilonidal sinus patientswere treated with any alternative elective operation.

Median length, width, and weight of the excisedellipse were 7 (range, 5–15) cm, 5 (range, 4–7) cm, and 34(range, 8–130) g, respectively. The median caudal limit ofthe ellipse was 6 (range, 1–11) cm from the anal verge.Median time in the operating room was 66 (range, 43–116) minutes, and median operating time from probingthe sinus to applying the final dressing was 35 (range, 22–68) minutes.

The median volume of drain contents was 0 (range,0–45) ml. Median postoperative pain score was two(range, 0–9). No patients required readmission to thehospital. During the seven days after surgery, the patientcohort had a total of 90 contacts with their primary carepractices, with a median of two contacts per patient.Primary care input was usually for wound checks anddressing changes by a nurse.

Ten patients’ wounds had postoperative discharge.Culture of swabs from these wounds grew Staphylococcusaureus in five, Streptococcus milleri in two, and mixedanaerobes in three. No patients needed surgical drainageof infection after the Karydakis flap operation. Follow-upwas achieved in all patients until wound healing wascomplete. Forty-one patients achieved healing by primaryintention. Eight patients experienced superficial, self-limiting separation of the skin at the caudal 1 or 2 cm

ANDERSON ET AL.: DAY-CASE KARYDAKIS FLAP 135

of their wound. Two patients had more substantialdehiscence that required wound packing. Median timeto complete wound healing was three (range, 2–9) weeks(Fig. 1). Table 1 shows the relationship between theassessed factors and wound healing time. Smokersexperienced quicker healing than nonsmokers. No otherfactor was significantly associated with the duration ofwound healing.

Two patients were lost to follow-up after their woundhad healed but before they returned to normal activity.Median time to return to work or full-time education wasthree (range, 1–8) weeks for the 49 patients for whomcomplete follow-up was available. Forty-seven of thesepatients (95 percent) returned to normal activity withinone month of surgery. By November 30, 2006, medianfollow-up was 13 (range, 2–25) months. No patients hadrequired further pilonidal surgery after their Karydakisflap procedure and none had presented with a recurrentpilonidal sinus.

DISCUSSION

The average hospital stay for treatment of pilonidal sinusin England between 2000 and 2001 was 4.3 days.1 It isrecognized that the asymmetric closure technique of theKarydakis flap achieves primary healing and low recur-rence rates in patients with pilonidal sinus.4 In addition,this study demonstrates that day-case Karydakis flap surgeryis feasible, safe, and effective. There was no need for hospitalreadmission, sepsis drainage, or surgery for recurrentsinus. Another recent report supports these findings.16 Thepresent project’s results allow accurate planning of operat-ing lists and informed consent of patients. Furthermore,there was no evidence that a substantial medical or

nursing burden had simply been transferred from thehospital to the primary care health service. This observationwas made in a population experiencing relatively high levelsof socioeconomic deprivation as illustrated by their DEP-CAT scores.

The Karydakis flap follows a clear recipe as describedby Kitchen 5 and is readily reproducible. It was possible toconstruct a Karydakis flap even in those patients whosedisease was only 1 cm from the anal verge. In thesecircumstances, the flap was dissected in the ischiorectal fatoutside the external anal sphincter. A modification ofKitchen’s operative description involved placing thecaudal tip of the excised tissue 3 cm lateral to the natalcleft. Before the study, this technique was found to solvethe observed problem of the distal portion of the finalwound curving medially toward the anus. Familiarity with

FIGURE 1. Time to complete healing after Karydakis flap for pilonidalsinus.

Table 1. Wound healing

Parameter SubsetNo. ofpatients

Time towoundhealing(wk)

P value(log-rank)

Gender Male 41 3 (2–9) 0.228Female 10 3 (2–6)

Age (yr) 16–22 18 3 (2–7) 0.21623–29 16 3 (2–9)30–46 17 3 (2–8)

Body massindex

≤30 33 3 (2–9) 0.858>30 18 3 (2–8)

Deprivationcategory

1–2 1 2 (2–2) 0.43–4 16 3 (2–9)5–7 34 3 (2–8)

Employment Education 3 3 (2–7) 0.7Manual 22 3 (2–8)Non-manual 17 3 (2–9)Unemployed 9 3 (2–4)

Smoking Nonsmoker 24 3 (2–8) 0.017Smoker 27 3 (2–9)

Cavitylength(cm)

1–2 19 3 (2–6) 0.2873–4 14 3 (2–8)5–12 18 3 (2–9)

Cavity-anus(cm)

1–5 16 3 (2–9) 0.1773–4 13 3 (2–6)5–12 22 3 (2–8)

Ellipselength(cm)

5–6 18 3 (2–8) 0.67–8 18 3 (2–6)9–15 15 3 (2–9)

Ellipse width(cm)

4 8 3 (2–6) 0.7075 34 3 (2–8)6–7 9 3 (2–9)

Ellipseweight (g)

8–26 17 3 (2–8) 0.17627–50 17 3 (2–5)51–130 17 3 (2–9)

Ellipse-anus(cm)

1–4 14 3 (2–9) 0.2465–6 17 3 (2–6)7–11 20 3 (2–8)

Drainvolume(ml)

0 29 3 (2–9) 0.5782–5 7 3 (2–8)10–45 15 3 (2–6)

Data are medians with ranges in parentheses unless otherwise indicated.

ANDERSON ET AL.: DAY-CASE KARYDAKIS FLAP136

the procedure was enhanced by concentrating the electivepilonidal sinus referrals in the practice of one surgeon in aunit of ten general surgeons.

Early in the study, a weakness was recognized relatingto patient consent. It was clear that some subjects weresurprised by the degree of flattening of their natal cleft.Thereafter, this aspect of the procedure was emphasizedwhen consenting patients and the use of photographs of“typical examples” has been considered.

It is recognized that outcome after pilonidal sinussurgery is procedure dependant.3,17 However, subjectiveassessment of patients with pilonidal sinus disease sug-gests that some are easier to operate on than others.Patients with multiple sinuses, extending over the lengthof the natal cleft and close to the anus, with lateralsecondary openings clearly represent different challengescompared with those with more localized disease that isdistant from the anus.8 In the present study, half of thepatients who experienced superficial dehiscence of thecaudal end of their wound had an incision that extendedto 1 cm from the anal verge. A report of 41 patients inEgypt showed that pilonidal sinus patients with a BMI>30 were more likely to experience complications.7 Thepresent study confirms that pilonidal sinus occurs par-ticularly in young, overweight males. Eighteen patientshad a BMI >30 in the present study but wound healingtook longer than three weeks in only four of these patients.Some anesthetists may be reluctant to undertake day-casesurgery under general anesthesia in the prone position inoverweight patients. Our hospital’s day-surgery policyincludes an upper BMI limit of 35. Three anesthetistscontributed to the present study and all patients receivedfull endotracheal intubation.

Examination of plausible factors that might be as-sociated with wound healing was problematic because ofweekly assessment and the short time from surgery towound healing in the majority of patients. For example,38 patients (75 percent) attained wound healing betweentwo and three weeks after surgery but only 13 patients(25 percent) took longer to heal. The relatively favorablehealing time experienced by smokers was unexpected andthe reasons underlying this observation are not clear. Thepresent study did not reveal any other specific factors thatmight predict delayed wound healing, but the rather smallcohort does not preclude such an association. Neverthe-less, this study is one of the few to examine such factorsand therefore provides important new information onwhich to base further assessments of this procedure. Theresults suggest that delays in wound healing beyond threeweeks are relatively uncommon.

The present prospective cohort was assessed by anexperienced nurse who was independent from the surgi-cal team. Consequently, we avoided the potential biasassociated with surgeons’ evaluation of their own practice.Quality of life after pilonidal sinus treatment may be

related to the choice of surgical technique.18 It has beenrecommended that studies of pilonidal sinus treatmentshould address not only healing time and recurrence butalso patient’s inconvenience and time off work.17 Most ofour patients returned to normal activities within onemonth of surgery.

Future work should encompass prolonged follow-upof this cohort to offer valid sinus recurrence data; recur-rences may not declare themselves until more than threeyears after surgery.17 Furthermore, it would be interestingto explore whether the suction drain and prophylacticantibiotics are essential. Surgical instinct supports the useof prophylactic antibiotics in potentially contaminatedprocedures. One randomized, controlled trial has shownthat suction drainage is associated with a significant re-duction in postoperative complications.8 The merits ofrandomized, controlled comparisons of surgical proce-dures are acknowledged but the low incidence of healingby secondary intention or sinus recurrence after theKarydakis flap operation would necessitate large cohortsto provide adequate statistical power.

CONCLUSIONS

The Karydakis flap is readily reproducible and requiresone hour of operating room time. Day-case surgery isfeasible, safe, and effective. A review of pilonidal sinusmanagement in 199017 stated, “No method satisfies allrequirements for the ideal treatment—quick healing, nohospital admission, minimal patient inconvenience, andlow recurrence.” Day-case Karydakis flap may be theanswer to this challenge.

ACKNOWLEDGMENTS

The authors thank Dr. D. C. McMillan and Professor C. W.Imrie for reviewing the manuscript and the staff of GlasgowRoyal infirmary’s Day Surgery Unit for assistance.

REFERENCES

1. Editorial. Pilonidal disease: is surgery alone enough? ColorectalDis 2003;5:205.

2. da Silva JH. Pilonidal cyst: cause and treatment. Dis ColonRectum 2000;43:1146–56.

3. Petersen S, Koch R, Stelzner S, Wendlandt TP, Ludwig K.Primary closure techniques in chronic pilonidal sinus: asurvey of the results of different surgical approaches. DisColon Rectum 2002;45:1458–67.

4. Karydakis GE. Easy and successful treatment of pilonidalsinus after explanation of its causative processes. ANZ JSurg 1992;62:385–9.

5. Kitchen PR. Pilonidal sinus: experience with the Karydakisflap. Br J Surg 1996;83:1452–5.

6. Anyanwu AC, Hossain S, Williams A, Montgomery AC.Karydakis operation for sacrococcygeal pilonidal sinus

ANDERSON ET AL.: DAY-CASE KARYDAKIS FLAP 137

disease: experience in a district general hospital. Ann R CollSurg Engl 1998;80:197–9.

7. Sakr M, El-Hammadi H, Moussa M, Arafa S, Rasheed M.The effect of obesity on the results of Karydakis techniquefor the management of chronic pilonidal sinus. Int JColorectal Dis 2003;18:36–9.

8. Gurer A, Gomceli I, OzdoganM, OzlemN, Sozen S, Aydin R.Is routine cavity drainage necessary in Karydakis flap op-eration? A prospective, randomized trial. Dis Colon Rectum2005;48:1797–9.

9. Kulacoglu H, Dener C, Tumer H, Aktimur R. Totalsubcutaneous fistulectomy combined with Karydakis flapfor sacrococcygeal pilonidal disease with secondary perianalopening. Colorectal Dis 2006;8:120–3.

10. Patel H, Lee M, Bloom I, Allen-Mersh TG. Prolonged delayin healing after surgical treatment of pilonidal sinus isavoidable. Colorectal Dis 1999;1:107–10.

11. Akinci OF, Coskun A, Uzunköy A. Simple and effective surgicaltreatment of pilonidal sinus. Dis Colon Rectum 2000;43:701–7.

12. Senapati A, Cripps NP, Thompson MR. Bascom’s opera-tion in the day-surgical management of symptomaticpilonidal sinus. Br J Surg 2000;87:1067–70.

13. Bascom J, Bascom T. Failed pilonidal surgery: new paradigmand new operation leading to cures. Arch Surg 2002;137:1146–50.

14. Søndenaa K, Andersen E, Nesvik I, Søreide JA. Patientcharacteristics and symptoms in chronic pilonidal sinusdisease. Int J Colorectal Dis 1995;10:39–42.

15. McLoone P. Carstairs scores for Scottish postcode sectorsfrom the 1991 census. Public Health Research Unit, 1993.

16. Abdul-Ghani AK, Abdul-Ghani AN, Ingham Clark CL. Daycare surgery for pilonidal sinus. Ann R Coll Surg Engl2006;88:656–8.

17. Allen-Mersh TG. Pilonidal sinus: finding the right track fortreatment. Br J Surg 1990;77:123–32.

18. Ertan T, Koc M, Gocmen E, Aslar AK, Keslek M, Kilic M.Does technique alter quality of life after pilonidal sinussurgery? Am J Surg 2005;190:388–92.

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