4. Discussion
The present study is one of the largest studies till date, which demonstrates that laying open and curettage of the pilonidal cavity under local anesthesia (LOCULA) is associated with a remarkably high success rate on long-term follow-up. The study is not novel as the LOCULA procedure and its distinct advantages over other techniques have been described previously [
11]. Still, this procedure is not widely used. In addition to being one of the largest studies with the LOCULA procedure, this study highlights its efficacy on a long-term basis. Therefore, the present study would help establish this technique as the frontline procedure for management of all pilonidal sinus disease types.
In the LOCULA procedure, no attempt is made to excise the sinus. Only deroofing (laying open) is performed, and the overhanging margins are partially trimmed to create a saucer-shaped wound (
Figure 1). This helps prevent adherence of wound edges, thus promoting healing by secondary intention. As no excision is done, the procedure is very simple, less time-consuming, associated with little bleeding, and the resulting wound is relatively small (
Figure 1). Thus, postoperative pain is minimal, and most patients do not require any analgesics three days after the procedure.
As demonstrated by this study, there are distinct advantages of the LOCULA procedure. It can be done under local anesthesia, is a simple procedure requiring short operating time, needs only a small incision as the pilonidal sinus/cavity is not excised but merely deroofed (
Figure 1), does not require admission, allows early resumption of everyday activities, is associated with a high cure rate (98% in the present study), and can be done in all types of PSD [simple as well as complicated (recurrent, deep, multiple branches etc.)], can be done as a first-line definitive procedure in cases of pilonidal sinus with abscess, can be repeated easily in case of a recurrence, is easy to learn and replicate, does not require any expensive tools like laser or endoscopic equipment, and does not flatten the contour of the upper buttocks.
However, there were two distinct disadvantages of the LOCULA procedure. First, wound healing takes approximately 5–8 weeks. However, in reality, this prolonged healing duration does not bother the patient much, as it does not interfere with their normal routine or professional work. Second, local hygiene and care (hair removal and powder application) are required for a few years.
The recurrence rate of 1.9% after LOCULA is comparable to the recurrence rate reported after other procedures routinely performed to treat PSD: 0–11.9% for excision with open healing [
12,
13], 0–7.1% for excision with marsupialization [
12,
13], 0–20% for excision with midline closure [
12,
13,
14], 0–11% for excision with off midline closure with different flaps [
12,
13,
14], 2–9% with laser treatment [
9] and 1–8% with endoscopic procedures [
10].
LOCULA should not be confused with simple incision and drainage of an acute pilonidal abscess. The latter was associated with a recurrence rate of up to 24% [
2,
15,
16,
17]. However, when the cavity was curetted along with incision and drainage, the recurrence rate reduced significantly. A large study (150 patients) with long-term follow-up (65 months) demonstrated that the cure rate rose from 46% to 90% when curettage was added to simple incision and drainage of pilonidal abscess [
17]. The reason was that thorough curettage of the sinus cavity removed all the debris and infected granulation tissue and helped identify any side branches/extensions, which were then laid open.
Wide excision had been advocated for PSD for several years. An important point to debate is why a simple infected wound should undergo excision and that too wide excision? PSD is not a malignancy, and wide excision is perhaps not warranted [
11]. If wound closure is contemplated after wide excision of PSD, a variable degree of tension in the closed wound is inevitable because of tissue deficit. Consequently, a flap is usually required to allow wound closure without tension. PSD is like any ordinary subcutaneous abscess with a ‘slightly different etiology’. Wide excision and primary closure are not required in any subcutaneous abscess anywhere else in the body; similarly, wide excision is perhaps not needed in PSD.
Various causative factors such as hairs, prolonged sitting, overweight, etc., predispose to PSD development. We suspect that excessive sweating may be one of the causative factors as well, but there is currently no proof. Hair is one of the leading causative factors for PSD [
18,
19,
20,
21]. Conventionally, it is believed that hair fragments from the intergluteal fold are responsible for PSD [
3,
8]. However, the latest research on the origin of the causative hair suggests that occipital hair could be responsible for PSD rather than hair from the intergluteal fold or lumbar region [
22,
23,
24]. These two causative factors (hair and suspectedly sweating) are important because they are the only two modifiable risk factors and can help prevent the disease in the future. These can be easily modified by regular removal of hair (or decreasing hair growth by the laser procedure) and frequent talcum powder application in the intergluteal cleft. These lifestyle changes need to be maintained for at least five years after the procedure. This protocol was followed in this study, and it was significantly effective in preventing recurrence in the healed patients on long-term follow-up. A flap procedure can circumvent the need for these precautions as it flattens the upper buttocks’ contour. Once the natal cleft is flattened, accumulation of hair and sweat in the intergluteal cleft is drastically reduced, and hence the likelihood of recurrence is minimized. But, a significant proportion of patients prefer to prevent disease recurrence by countering predisposing factors rather than by altering their anatomy [
18]. This was highlighted in a recent study in which 97.1% of patients did not prefer a flap procedure but opted for techniques that preserved the contour of the upper buttocks [
18]. They did not mind hair clearing and powder application to prevent the disease recurrence [
18]. The main reasons for not preferring procedures that flatten the upper buttocks (flap procedures) were the permanent change in anatomy, more prominent scar, and loss of cosmesis (since the presence of a cleft in upper buttocks may have cosmetic value). Since PSD is primarily a disease of young people [
18], it is understandable that many young patients would not agree to flatten their gluteal contour.
With the advent of endoscopic surgery in other parts of the body, endoscopy has also been performed in PSD [
10]. The use of endoscopic equipment can be justified when the surgery is performed in a deep plane, but when the pathology is just skin-deep, the use of endoscopic procedures seems illogical. It is in effect advocating an endoscopic approach to drain and cauterize a small subcutaneous abscess. Moreover, endoscopy increases the cost without substantially increasing the success rate [
19].
As newer technologies using lasers were developed, these were also utilized in the treatment of PSD [
10]. This unnecessarily increased the cost of the treatment. The use of expensive equipment (as required in laser procedure) is perhaps not needed, as the same purpose (ablation of the infected epithelium of the pilonidal tract/cavity) can be conveniently achieved with electrocautery at nominal cost [
10,
19].
The study had limitations. First, the study would have been much more informative if there were two comparative groups with properly calculated sample size in each group, and the success rate, healing time, and complications between them could be statistically compared. Second, though the procedure was associated with minimal pain and most patients could resume work within 3–4 days, the pain assessment should have been done by an objective pain scoring system and a patient satisfaction survey. That would have enhanced the objectivity of the results of the study.
