Over the past few decades in the management of sacrococcygeal pilonidal sinus disease, surgeons have increasingly come to appreciate the importance not only of flattening the natal cleft but also of achieving an off-midline closure of the resultant defect in order to minimize wound-related complications and recurrence.1–3 Asymmetric closure techniques used in the management of sacrococcygeal pilonidal sinus disease include the Karydakis flap and the Limberg flap.4–11 Both techniques aim at achieving an off-midline closure of the surgical wound after excision of the diseased natal cleft.4–11 The superiority of these techniques over primary midline closure techniques has been repeatedly demonstrated.12,13
The classic Karydakis flap consisted of an asymmetrical elliptical excision of the diseased raphe, mobilization of a flap from the median side of the wound, fixation of the base of the flap to the sacral fascia, and suturing of its edge to the lateral one.4,5 The classic technique aims to remove the vulnerable raphe and replace it with healthy tissue. In a modification proposed in 2007,14 the base of the flap was not fixed to the sacral fascia but rather sutured directly to the lateral edge of the wound.14 The aim of the modified technique was to remove the vulnerable raphe and avoid creation of a new one by flattening the natal cleft.14
The classic Limberg flap consisted of a symmetrical rhomboid-shaped excision of the diseased raphe with the apices of the rhombus placed on the midline, medial mobilization of a fasciocutaneous rhomboid transposition flap tailored on the gluteal region to fill the rhomboid defect, and direct closure of the resultant defect in the donor region.8–11 With this design, the lower midline apex of the rhombus was both the source and site of recurrence in many patients.15–19 To avoid this drawback, a modification of the classic Limberg flap was proposed in 2004.15 In the modified version, the rhomboid-shaped excision was asymmetrically constructed to place the lower apex of the rhombus 1 to 2 cm lateral to the inferior midline.15–19 Several studies have shown the modified Limberg flap to be superior to the classic version in minimizing wound complications and recurrences.18,19
To the present author’s best knowledge, no randomized study has yet compared these specific modified techniques. The aim of the present study was therefore to compare the short-term results of the management of sacrococcygeal pilonidal sinus disease with the modified Karydakis flap vs the modified Limberg flap in a randomized controlled trial.
PATIENTS AND METHODS
This was a prospective randomized controlled trial with parallel-group and balanced randomization [1:1]. The study was conducted at Alexandria Main University Hospital, Alexandria, Egypt, a 1000-bed teaching hospital owned by the Faculty of Medicine of the University of Alexandria. The protocol was approved by the ethics committees of both the General Surgery Department and the Faculty of Medicine of the University of Alexandria.
Patients were randomly assigned to undergo surgery with either the modified Karydakis flap or the modified Limberg flap. Randomization was performed by using a pseudorandom number generator with individual assignments concealed in sequentially numbered sealed envelopes that were opened in order when assignments were made. Randomization and allocation of patients to the groups were managed by an independent observer, and the surgeon was informed of the type of surgery to be performed at the time of induction of anesthesia. The independent observer was a dedicated research doctor who manages our surgical unit’s database and related research subjects. In addition, he measured the operative time in the present study. The postoperative assessors included the operating surgeon and 2 professors of surgery from the same department. The 2 independent assessors reported the presence or absence of any complication and the operating surgeon managed complications when present.
Eligible participants were patients presenting with chronic sacrococcygeal pilonidal sinus disease treated at Surgical Unit B of the Department of General Surgery from February 2009 to September 2011. Chronic disease was defined as “constant or recurrent symptoms observed over a period of several months without indication of spontaneous healing.”20 Before definitive surgical treatment was begun, septic complications were first treated aggressively. Acute pilonidal abscesses were initially incised and drained under a local anesthetic in the outpatient clinic, and antibiotics were prescribed. Similarly, patients presenting with chronic purulent discharge were initially treated with frequent dressings and antibiotics guided by the results of culture and sensitivity studies. Definitive surgery was performed no less than 3 weeks after evident sepsis has been eradicated. Both the modified Karydakis flap and the modified Limberg flap were thoroughly explained to all patients, together with the benefits and risks involved. In addition, photographic examples of the final appearance of both procedures were shown to all patients. Written informed consent was obtained from patients who agreed to receive either procedure and to participate in the study. Patients who declined to undergo either procedure for cosmetic reasons were excluded from the study. Other exclusion criteria included patients with unilateral secondary openings located more than 2 cm from the midline, bilateral secondary openings, and secondary openings located near the anus.
All operations were performed under spinal anesthesia with the patient in the prone jackknife position and the buttocks not strapped apart. The buttocks were shaved immediately before surgery and the surgical area was disinfected with 10% povidone-iodine solution. All patients received a single intravenous dose of a third-generation cephalosporin before surgery.
The modified Karydakis flap procedure was performed as follows. An asymmetrical elliptical incision was made. The ellipse was based on the side of any secondary opening. If the sinuses were entirely central, either side was chosen. The upper and lower ends of the ellipse were placed 2 cm to the side of the midline. The scalpel was used to make the skin incision and diathermy was then used to remove the ellipse including all sinuses and secondary openings (when present) down to the muscle and sacral fascia. The medial side of the wound was then undermined just superficial to the underlying gluteus muscle fascia for a distance of at least 5 cm to produce a flap extending the full length of the wound. Next, the flap was sutured directly to the lateral edge of the wound, without fixation to the sacral fascia, by means of a layer of interrupted Vicryl 0/0 sutures (Ethicon Endo-Surgery, Cincinnati, OH) for the subcutaneous tissue placed at a maximum of 2 cm apart and interrupted vertical mattress silk 2/0 sutures (Ethicon Endo-Surgery) for the skin (Fig. 1).
The modified Limberg flap was performed as follows. An asymmetrical rhomboid-shaped incision was made. The scalpel was used to make the skin incision, and diathermy was then used to remove the rhombus, including all sinuses and secondary openings (when present) down to the muscle and sacral fascia. The cephalic apex remained on the midline and the caudal apex was placed 2 cm lateral to the inferior midline. Next, a fasciocutaneous rhomboid transposition flap was tailored on the gluteal region contralateral to the asymmetric lower apex of the defect, fully mobilized on its inferior edge, and transposed medially to fill the rhomboid defect without tension. The subcutaneous tissue was approximated with a layer of interrupted Vicryl 0/0 sutures, and the skin was approximated with interrupted vertical mattress silk 2/0 sutures (Fig. 2).
In both procedures, some common surgical steps applied. First, extreme caution was practiced to avoid inadvertent contamination of the wound when opening the track of the sinus or its ramifications. Second, the anatomic bands between the rectum and the skin of the lower midline sulcus were fully released. Third, before placing the subcutaneous sutures, an 18-French suction drain was placed in the resultant dead space and brought out well laterally through a separate stab incision. Fourth, the subcutaneous sutures always included the lower half of the cuticular layer of the dermis, because the surgeon’s personal experience had shown that purely subcutaneous sutures did not hold well. Finally, a light dressing was applied to the closed wound. All operations were performed by the same surgeon (S.S.B.).
All procedures were performed as day-case surgery. During their 8-hour hospital stay, patients were given intramuscular injections of 75 mg of diclofenac potassium (Cataflam, Novartis Pharma, Cairo, Egypt) on demand. On discharge, patients were instructed to pay meticulous attention to hygiene rules and to neither sit nor use a semisitting position for 2 weeks, with walking being unrestricted. In addition, patients were taught to estimate the daily effluent from the suction drain. The suction drain was removed when the effluent was less than 20 mL per 24 hours for 2 consecutive days. Finally, patients were asked to remove their gluteal hair as necessary for 6 months postoperatively. Sutures were removed on the 12th to 14th postoperative day, and patients were allowed to return to work by the third postoperative week.
Data Collection and Outcome Measures
Data concerning age, sex, BMI (kg/m2), duration of reported symptoms, and history of previous surgical treatment (when applicable) were obtained from all patients. Patients were followed up by physical examination weekly for the first 4 postoperative weeks, at the end of months 3, 6, 9, and 12, and every 6 months thereafter.
The primary end point was operative time. Secondary endpoints included the proportion of patients with postoperative complications, the proportion of patients who were satisfied with the cosmetic results, and the rate of recurrence.
Operative time was defined as the time from the start of skin incision to the end of the last stitch. Postoperative complications were recorded with emphasis on wound infection, wound disruption (full-thickness or cuticular), and subcutaneous fluid collections. Satisfaction with cosmetic results was determined at the end of the third postoperative month by asking patients whether they were or were not sufficiently satisfied with the cosmetic outcome of their operation to recommend the same operation to others. Recurrent disease was reported if observed at any time throughout the study period.
In the absence of previous studies comparing the modified Karydakis technique and the modified Limberg technique, no data were available to estimate an effect size that could serve as a basis for sample size calculations. In an attempt to overcome this limitation, we used the mean operative times for the original Karydakis technique compared with the modified Limberg technique from the study by Can et al21 to calculate the effect size d using Cohen’s formula. This initial power calculation suggested that a minimum of 56 patients per group would be required to detect a true difference of this size with a power of 80% at the 5% level of significance. All data analysis was performed with the Statistical Package for the Social Sciences version 18 software (IBM-SPSS, Chicago, IL). The Mann-Whitney U test and the Student t test were used to compare groups regarding continuous variables, and the χ2 and the Fisher exact test were used for categorical variables. All p values were 2-sided. A p < 0.05 was considered statistically significant. Values are expressed as the median (range) unless otherwise stated.
A flow diagram of patient disposition is shown in Figure 3. Of 154 patients screened, 14 did not meet inclusion criteria, and 15 refused to receive the modified Limberg flap for cosmetic reasons and therefore declined to participate. A total of 125 patients, including 112 men (93.3%) and 8 women (6.7%), were randomly allocated to the treatment groups; 120 patients completed the study (60 in each group). Patient age ranged from 15 to 41 years with a median of 23 years.
Patient characteristics are shown for each treatment group in Table 1. No significant differences were observed between the groups regarding age, sex distribution, BMI, duration of complaint, or history of recurrent disease.
As shown in Table 2, operative time was significantly shorter in patients who received the modified Karydakis flap than in those who received the Limberg flap (p < 0.001). Differences observed between the modified Karydakis vs the modified Limberg procedure were not significant for overall complication rate (23% vs 40%; p = 0.08) or number of patients with more than 1 complication (21% vs 42%; p = 0.20).
No patient in the modified Karydakis group had full-thickness wound disruption, but this complication occurred in 9 patients (15%) in the modified Limberg flap group (p = 0.003; Table 2), occurred exclusively on the side of the asymmetric lower apex of the rhomboid defect (ie, flap recipient side). This was limited to the inferior suture line in 6 patients (10%) and included both superior and inferior suture lines in 3 patients (5%). Full-thickness wound disruption resulted in loss of alignment between the edge of the flap and the gluteal edge of the wound, with the flap dropping toward the sacrum. Loss of alignment occurred after the seventh postoperative day in all 9 patients with full-thickness disruption, and resuturing was performed in all 9 patients with 1/0 silk mattress sutures under local anesthesia. Resuturing was not successful in any of the patients, and full thickness wound disruption occurred again within 1 week. Healing by secondary intention required a median of 6 (range, 5–9) weeks in these 9 patients (15%), 4 of whom were obese. None of them had experienced a wound infection before the disruption. No cases of full-thickness wound disruption were encountered in the modified Karydakis flap group. The groups did not differ with regard to cuticular disruption at the lowermost 1 to 2 cm of the wound (p = 0.27; Table 2). This condition was managed with daily dressings and eventually healed completely without adverse sequelae.
Patients with the modified Karydakis flap also did not differ significantly from those with the modified Limberg flap with regard to wound infections (p = >0.99; Table 2), which were managed with antibiotics along with daily dressings and did not lead to wound breakdown in any patient in this study. In the modified Karydakis flap group, the drain remained for a median of 9.5 (range, 7–12) days compared with a median of 4 (range, 3–6) days in the modified Limberg flap group (p < 0.001). No significant between-group differences were found in subcutaneous fluid collection (p = 0.24; Table 2). In the 3 patients in the Karydakis group, the fluid accumulation was attributed to the accidental dislodgment of the suction drain on the third and fourth postoperative days. Repeated aspiration for 2 to 3 times was not followed by recollection in any of these 3 patients. The groups also did not differ regarding the occurrence rate for hypoesthesia (p = 0.09; Table 2), which was one of the complications found in all 13 patients who developed 2 complications. Hypoesthesia required no treatment and resolved completely by the sixth postoperative month in all patients. No deeply seated abscesses requiring deliberate opening of the wound for drainage or flap necroses were encountered in either study group.
A significantly higher rate of satisfaction with the cosmetic outcome of the operation and willingness to recommend it to others compared was found in the modified Karydakis flap group than in the modified Limberg flap group (p < 0.001; Table 2).
The median follow-up duration in both study groups was 20.5 (range, 6–36) months. The groups did not differ significantly with regard to recurrence of disease (p > 0.99; Table 2).
The present randomized controlled study compared the modified Karydakis flap and the modified Limberg flap in the surgical management of sacrococcygeal pilonidal sinus disease and found significant differences between the groups in short-term results regarding operation time, full-thickness wound disruption with a need for resuturing, and patient satisfaction.
Previous studies comparing the classic Karydakis flap with either the classic or the modified Limberg flap have demonstrated significantly shorter operative times for the classic Karydakis flap.21,22 The reduction in operative time has been attributed to the relatively straightforward nature of the classic Karydakis flap, in which extensive mobilization and real transposition are not required.21 Whereas in the previous studies operative times were approximately 40 minutes for the classic Karydakis flap compared with approximately 50 minutes for the Limberg flap.21,22 In the present study, the median operative time was 33 minutes for the modified Karydakis flap group and 52 minutes for the modified Limberg flap group (p < 0.001). The shorter operative time with the modified Karydakis flap compared with the classic Karydakis flap is understandable because the modified technique does not require fixation of the base of the flap to the sacral fascia. Omitting this suture line in the modified technique probably shortens the operative time.
The present study showed no significant differences between groups in overall postoperative complication rates. Because the power calculations to determine sample size were based on expected differences in operative times, it is unclear whether the study was sufficiently powered to detect a true difference in complication rates, if one existed. However, similar findings were reported in studies comparing the classic Karydakis flap to the Limberg flap.21,22 In the present study, septic complications were treated aggressively before surgery, and the wound infection rate was low in both treatment groups. This result emphasizes the importance of avoiding surgery in the presence of active sepsis and the need for aggressive preoperative eradication of such sepsis when attempting flap surgery for sacrococcygeal pilonidal sinus disease.
The rates of wound dehiscence reported in earlier studies comparing the classic Karydakis flap to the classic or modified Limberg flap have ranged from 0% to 6% for the classic Karydakis flap compared with 0% to 14% for the Limberg flap.21–23 In the present study, none of the patients who received a modified Karydakis flap but 9 patients (15%) of the modified Limberg flap group had wound dehiscence (p = 0.003). In 6 of these, full thickness wound disruption occurred exclusively on the flap recipient side and was limited to the inferior suture line, and in 3 patients both superior and inferior suture lines were involved. Morphologic differences between the 2 types of flap might explain such findings. The modified Limberg flap is a fasciocutaneous transposition flap, in which part of the fascia underlying the strong gluteal muscles is mobilized to be sutured to the edges of the defect, and the base of this fascial flap remains attached to those strong muscles. Walking might induce either traction on the flap or strong friction between the flap and the recipient side edges of the wound, which might lead to disruption in some patients. Several observations from the current study may provide evidence to support this suggestion. First, none of the patients had a wound infection prior to disruption. Second, such disruption usually presented after 7 postoperative days of free mobility. Third, the loss of alignment between the disrupted edges and failure of resuturing suggests the presence of either traction or friction forces that did not allow healing. In contrast, the modified Karydakis flap, which consists only of skin and subcutaneous tissue, is dissected from the underlying gluteal muscle and fascia and is laterally advanced for a distance of at least 5 cm from the suture line. In such a design, the forces on the suture line produced by walking may not be strong enough to disrupt the wound. The question of whether the omission of the fascial component in the modified Limberg flap would help to avoid such disruptions awaits the results of future studies. In both groups of the present study, cuticular disruption at the lowermost 1 to 2 cm of the wound was easily managed by means of daily dressings and eventually healed completely, without adverse sequelae because it was usually located off the midline.
The routine use of suction drains has been previously advocated for both the Karydakis and Limberg techniques,10,14–19,24,25 and this policy was successful in preventing postoperative subcutaneous fluid collections in the current study, with the exception of 3 patients (5%) in the modified Karydakis flap group in whom fluid collection was a consequence of early accidental dislodgment of the drain.
Urhan et al9 reported that after the classic Limberg flap procedure, 25 patients (25%) developed minimal hypoesthesia which caused no discomfort. In contrast, Kitchen6 reported hypoesthesia after receiving the classic Karydakis flap in 17 patients (12%). In the present study, hypoesthesia occurred in only 6 patients (10%) in the modified Karydakis flap group but in 14 patients (23%) in the modified Limberg flap group; however, the difference was not significant (p = 0.09). In all patients, hypoesthesia was minimal, transient, and resolved spontaneously by the sixth postoperative month.
In the present study, compared with patients who received the modified Karydakis flap, significantly fewer patients with the modified Limberg flap were satisfied with the cosmetic outcome and willing to recommend it to others, although they had viewed photos of its final appearance before consenting to receive it. Lack of satisfaction did not appear to be associated with wound complications. This assessment was done at the end of the third postoperative month, when wounds were completely healed and no complications were present at the time of assessment. Of the 9 patients who developed full-thickness wound disruption (the most serious complication of the procedure), 5 patients were dissatisfied with the cosmetic outcome. However, 12 more patients were dissatisfied although they had not developed wound disruption and had experienced an uneventful postoperative course. Furthermore, 15 patients declined to participate and were excluded from the study because they refused to receive the modified Limberg flap because of its cosmetic appearance. Eryilmaz et al26 reported that as many as 37% of their patients were not pleased with the appearance of the Limberg flap. Similarly, Ates et al22 reported that the mean score for patient satisfaction with the appearance of the scars was 7.08 (SD, 1.75) in the Karydakis group compared to 3.16 (SD, 1.4) in the Limberg group (p < 0.01). The results of the present study add further evidence to the cosmetic preferability of the Karydakis flap as previously pointed out by others.22
In accordance with earlier studies,21,22 no significant difference was found between groups in the present study regarding disease recurrence.21,22 However, because the follow-up period was relatively short (median, 20.5 months), recurrence was not a major focus of the current analysis, and Kaplan-Meier time-event-analyses were not applied. Longer follow-up periods are still required to draw more definite conclusions as to whether the modified Karydakis and Limberg techniques achieve comparable recurrence rates.
Both the modified Karydakis flap and the modified Limberg flap provide effective treatment for sacrococcygeal pilonidal sinus disease and can be performed safely as day-case surgery. The modified Karydakis flap is associated with significantly shorter operative time, a lower full-thickness wound disruption rate, and a higher patient satisfaction rate.
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