Evidence - Karydakis flap procedure for pilonidal sinus

  1. Literature summary

    According to recent findings, pilonidal sinus is an acquired disease, while the congenital origin discussed in the past seems unlikely today.

    The following factors are assumed to be predisposing in the development: Male sex, obesity, excessive hair in the anal cleft, poor personal hygiene, sitting occupations, deep gluteal fold, positive family history.

    Hair plays a special role in this context: As early as the 1980s, F. Stelzner proved that hair, fixed by small barbs, can penetrate the skin. A further indication that hair plays an important role is the fact that pilonidal sinus is unknown in China since Chinese have no hair in the anal cleft.

    The latest 2014 update of the guideline of the German Society of Coloproctology of recommends surgery as the treatment of choice.
    The abscess is first unroofed widely to allow effective drainage. Definitive treatment of the pilonidal sinus is then performed in the second stage by following one of these two procedures:

    • Excision with secondary wound healing or
    • Excision with primary wound closure (only in infect-free stage!) → after excision, the wound is primarily closed by suture or plastic reconstruction.

    Local or systemic antibiotics should not be administered because they do not result in definitive healing of the sinus. The injection of phenol solution is obsolete because of its high toxicity and possible absorption of the phenol.

    There is no spontaneous healing. An asymptomatic pilonidal sinus persists for life but may also enter the acute (abscess) or the chronic stage. Malignant transformation is possible in long-standing pilonidal sinus. Davis et al., Kulaylat et al. found more than 40 such cases by 1966, and 80% were squamous cell carcinoma.

    After excision, healing by secondary intention does not tend to be significantly more effective than primary wound closure.

    While all studies demonstrate a tendency toward low recurrence rates after secondary wound healing, significance was never reached.

    It is widely believed that secondary wound healing results in lower recurrence rates. Theoretically, a stable scar is formed and thus there can be no recurrence in the hairless scar tissue. This theory is not borne out by the literature. In his 1990 review, Allen-Mersh already pointed out that open wound treatment is associated with a mean recurrence rate of 13%. Doll et al. recently reported an actuarial recurrence rate of 22% after a follow-up period of almost 15 years.

    As a matter of principle, the pilonidal sinus should be excised in toto. Typically, the excision of the granulation pannus must be carried down close to the sacral fascia. In the literature, however, there is no sure indication that this should involve the periosteum. In contrast, however, it must be presumed that excision of the periosteum denuding the sacrum will increase postoperative pain.

    In order to ensure full excision, it is recommended to mark the rabbit warren of inflamed tissue with methylene blue. Doll et al. were able to demonstrate that the use of methylene blue has a significant impact on the recurrence rate.

    Primary mid-line wound closure after excision of pilonidal sinus correlates with a high postoperative morbidity and recurrence rate. In primary mid-line wound closure, the incidence of wound healing disorders is 30% or more.

    In open wound treatment, it is not unusual for the healing to take more than 3 months.

    Due to the prolonged postoperative treatment and the socio-economic burden, open wound treatment is not an optimal alternative. Surgical techniques avoiding a median wound and flattening the gluteal fold appear to be useful and provide better short-term and long-term results.

    As early as 1973, Karydakis reported on the results of a new surgical technique he had developed for the treatment of pilonidal sinus. The surgical principle was based on the pathogenesis of the disease postulated by the author.

    The axis of the ellipsoidal incision should be 2-3 cm lateral to the midline on the side where the disease is more pronounced. The fistula openings in the natal cleft (primary porus or pori) must be excised, while the secondary openings may be left in place if these are outside the area excised. A sparing excision of the skin around the secondary fistula opening will be adequate. After marking the incision line, the skin is excised together with the subcutaneous fatty tissue. The thickness of the resection should not exceed 1cm, otherwise the defect would become too large and difficult to close. A flap, including the subcutaneous fatty tissue, is mobilized on the contralateral side, the width of the flap being 2-3cm and its thickness 1cm. The flap is gathered at its lateral margin with a series of absorbable stitches 2-0 and sutured exactly to midline. In the midline he sacral fascia and capsule of the pilonidal sinus create a solid anchor for the sutures. The inserted suction drainage will prevent hematoma formation. This is followed by a row of subcutaneous sutures and the skin suture.

    The reported recurrence rate in more than 6000 patients operated on by Karydakis was less than 1%, while postoperative morbidity of mostly superficial wound infections was below 10%. Later other authors were able to replicate the good results with the Karydakis procedure.

    Potential objections to the Karydakis procedure include cosmetic changes to the buttocks and the presence of paresthesia. This intervention largely flattens the natal cleft. Particularly in women, this change in body contour must be discussed with the patient before the operation.

    Paresthesia at the site of the flap occurs frequently, sometimes lasting longer than one year. However, this does not burden the patients.

    Systemic preoperative prophylactic antibiotics do not appear to affect wound healing. This was demonstrated by the prospective randomized trial of Sondenaa. Other reports also confirmed this observation.
    The significance of a prophylactic postoperative antibiotic regimen in procedures with asymmetric wound closure (e.g. Karydakis procedure) or following flap surgery still remains unclear. Some authors report a positive effect of postoperative antibiotic therapy (ciprofloxacin, cefuroxime or metronidazole for 4-5 days) on the incidence of wound healing disorders.

    However, there has been no scientific proof that wound healing will benefit from postoperative antibiotic regimens.

    The skin sutures should be left in place for at least 14 days.

    A general recommendation for bed rest immediately after surgery is not evidence-based. Nevertheless, patients should be advised to remain in bed during the first days after surgery, and in the first few weeks after removal of the sutures should refrain from heavy physical activity.

    In theory, depilation should reduce the recurrence rate. Nevertheless, it has been known for some time that mechanical hair removal by shaving with a razor does not offer any benefit. Stirnemann and Blasimann already reported in 1983 that the recurrence rate cannot be reduced by mechanical shaving. A 2009 cohort trial by the German Armed Forces also demonstrated the same effect, with mechanical shaving even promoting the development of recurrences (Petersen 2009). Nevertheless, depilation without breaking any other hairs remains a promising treatment option in preventing relapse. Therefore, other hair removal modalities will have to prove their effectiveness. Laser epilation is the most important technique here. Removal of all hair in the natal cleft requires at least 5 sessions. Afterwards, the natal cleft will have less hair permanently.

  2. Ongoing trials on this topic

  3. References on this topic

    1. Karydakis GE. New approach to the problem of pilonidal sinus. Lancet 1973; 2: 1414

    2. Akinci OF, Coskun A, Uzunkoy A. Simple and effective surgical treatment of pilonidal sinus: asymmetric excision and primary closure using suction drain and subcuticular skin closure. Dis Colon Rectum 2000; 43: 701

    3. Anyanwu AC, Hossain S, Williams A, Montgomery AC. Karydakis operation for sacrococcygeal pilonidal sinus disease: experience in a district general hospital. Ann R Coll Surg Engl 1998; 80: 197

    4. Kitchen PR. Pilonidal sinus: experience with the Karydakis flap. Br J Surg 1996; 83: 1452

    5. Allen-Mersh TG. Pilonidal sinus: finding the right track for treatment. Br J Surg 1990; 77: 123

    6. Kronborg O, Christensen K, Zimmermann-Nielsen C: Chronic pilonidal disease: a randomized trial with a complete 3-year follow-up. Br. J. Surg. 72 (1985) 303-304

    7. Füzun M, Bakir H, Soylu M et al.: Which technique for treatment of pilonidal sinus – open or closed? Dis. Colon Rectum 37 (1994) 1148-1150

    8. Sondenaa K, Nesvik I, Andersen E et al.: Recurrent pilonidalsinus after excision with closed or open treatment: final result of a randomised trial. Eur. J. Surg. 162 (1996) 237-240

    9. Kitchen PR. Pilonidal sinus: experience with the Karydakis flap. Br J Surg 1996; 83: 1452

    10. Schoeller T, Wechselberger G, Otto A, Papp C. Pilonidal sinus: experience with the Karydakis flap. Br J Surg 1997; 84: 890

    11. Akinci OF, Bozer M, Uzunkoy A, Duzgun SA, Coskun A. Incidence and aetiological factors in pilonidal sinus among Turkish soldiers. Eur J Surg 1999; 165: 339–342

    12. Anyanwu AC, Hossain S, Williams A, Montgomery AC. Karydakis operation
    for sacrococcygeal pilonidal sinus disease: experience in a district general hospital. Ann R Coll Surg Engl 1998; 80: 197

    13. Bascom J. Pilonidal sinus: experience with the Karydakis flap. Br J Surg 1998; 85: 874

    14. Doll D, Novotny A, Rothe R et al. Blue halves the long-term recurrence rate in acute pilonidal sinus disease. Int J Colorectal Dis 2008; 23: 181–187

    15. Doll D, Krueger CM, Schrank S et al. Timeline of recurrence after primary and secondary pilonidal sinus surgery. Dis Colon Rectum 2007; 50: 1928–1934

    16. Iesalnieks I et al. Chirurgische Behandlung des Sinus Pilonidalis Viszeralchirurgie 2006; 41: 399–406

    17. I. Iesalnieks • A. Fürst • M. Rentsch • K.-W. Jauch Chirurg 2003 • 74:461–468 Erhöhtes Rezidivrisiko nach primärem medianem Wundverschluss bei Patienten mit Pilonidalsinus

    18. Sven Petersen Sinus pilonidalis Allgemein- und Viszeralchirurgie up2date 2 2011 151–166


Collings AT, Rymeski B. Updates on the Management of Pilonidal Disease. Adv Pediatr. 2022 Aug;69(1)

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