Surgical treatment of pilonidal disease
Authors: John Bascom
Journal: BMJ (2008)

In the accompanying paper, McCallum and colleagues report a systematic review of the effects of different surgical techniques for treating pilonidal sinus.1 Pilonidal disease is an infection in a “ditch” that results from mechanical stretch, which causes enlargement and rupture of hair follicles in the natal cleft.2 The disease is confined to skin and fat, can be acute or chronic, minor or major, and can range from an asymptomatic pinhole in skin to an abscess the size of an orange.

The disease affects mainly young men aged 15-30. McCallum and colleagues report an incidence of 26/100 000,1 but it varies by population—from 0.11% in women at college to 8.8% in Turkish soldiers. One large series reported that 78 924 US servicemen in the second world war were in hospital for an average of 55 days each with pilonidal problems, chiefly because of complications of wide excision.3 As a result, wide excision was banned by the surgeon general—a ban that was subsequently ignored. Pilonidal disease is often treated by removing the diseased skin and subcutaneous tissue completely. The surgical wound is either closed with sutures (for healing by primary intention) or packed open (to heal by second intention). Both treatments can lead to recurrences and unhealed wounds,3 4 so many clinical trials have compared whether it is better to pack the wound open or to close it.5

McCallum and colleagues’ study is a systematic review of such trials. It assesses the effects of open healing versus closed surgical treatment and the optimal method of closure (midline versus off-midline) for pilonidal sinus. The outcomes were time to healing, surgical site infection, and recurrence rate.1 The review found no significant difference between open and closed healing in the rates of surgical site infection, and recurrence was significantly less likely after open healing (relative risk 0.42, 95% confidence interval 0.26 to 0.66). Data were insufficient to make conclusions about time to wound healing. Compared with off-midline surgical closure, midline closure significantly increased healing time, recurrence, and infection of the surgical site.1

The authors conclude that based on current evidence, off-midline closure should become standard management of pilonidal sinus.1 The saying, “stay out of the ditch,” repeats the sense of their words, and these conclusions are supported by other reports.2 6

However, the review does not explore the more fundamental question of whether extensive excision is even necessary. The included trials analysed different methods of excising diseased tissue, but these methods were developed before our current understanding of pilonidal disease.

Two options are available for the treatment of pilonidal disease. Surgeons can remove tissue thickened by bacterial invasion or reshape the contours that fostered that invasion.6 Widely removing a pilonidal abscess treats pilonidal disease as if it were a malignancy. Reshaping it treats it as an infection, with the guiding principles being to drain abscesses and protect tissue from bacteria.7 8

So what should be considered best practice for the treatment of pilonidal sinus? For early primary disease collected hair and keratin can simply be removed from the pits of origin.9 In my opinion, Armstrong and Barcia describe this conservative management well and establish its desirable results,9 although they did not conduct a double-blind study to prove that their approach is superior to all other approaches to early primary pilonidal disease. For more advanced primary disease the tiny midline pits of origin can be excised and the abscess cavities cleaned out through off-midline incisions.2 For advanced disease involving deep clefts, multiple sinus tracts, and failure of previous surgery, the depth of the cleft should be reduced and use made of flaps and off-midline closure of the wound.1 8

Patients and clinicians can access the principles of off-midline care through a website operated by the Pilonidal Support Foundation (www.pilonidal.org/). The site maintains a fully accessible registry of surgeons familiar with off-midline repairs, which lists 58 surgeons worldwide including eight in the United Kingdom. As with laparoscopic gallbladder surgery, patients may become advocates of off-midline closure.

Future research should try to define why midline wounds are problematic. Is it unusual bacteria, low ambient oxygen in the cleft, or high pressures that trap pus? The surgical community is a tough nut to crack, but hopefully surgeons will take up these improved methods in the years to come. After all, it took nearly a century for the disproved theory of the congenital origin of pilonidal sinuses to die out.