Probe-Guided Core Excision for Complete Sinus Tract Removal in Pilonidal Disease

Dear Editor:

Pilonidal sinus disease is a chronic inflammatory disorder of the natal cleft characterized by one or more midline pits that communicate with epithelialized sinus tracts containing hair and keratinous debris¹,². It develops when loose hair migrates into a preexisting or acquired midline pit under repetitive shear forces, triggering a foreign body reaction, chronic inflammation, and sinus tract formation³. It often presents with chronic drainage and evolves into recurrent abscess formation. Therefore, complete eradication of the diseased sinus tract by surgical intervention is a key therapeutic goal in patients with established or recurrent pilonidal disease, regardless of the reconstruction method⁴.

Although various reconstructive strategies—including primary closure, secondary intention healing (SIH), and full-thickness flap reconstruction—have been described following pilonidal sinus surgery⁵, relatively few reports have focused on techniques specifically aimed at achieving complete eradication of the sinus tract itself. Herein, we present a retrospective review of our experience with probe-guided core excision, a practical technique designed to facilitate complete removal of the diseased tract while minimizing unnecessary tissue sacrifice.

This study was approved by Institutional Review Board (IRB) of Severance Hospital, Yonsei University (IRB number: 4-2025-1640). All participants provided written informed consent prior to enrollment, and the study was conducted in accordance with the Declaration of Helsinki.

Our approach utilizes a malleable probe as an intraoperative navigation to identify the entire sinus tract network. Preoperatively, tumescent local anesthesia was administered. The probe is then gently inserted through the primary pit to delineate the full extent of the tract. After probe insertion, the probe was advanced gently along the tract, and excessive force was avoided to reduce the risk of creating a false passage. The probe is passed from one end of the sinus tract to the other, ensuring thorough visualization of the tract's path. Once the probe was positioned, a fusiform incision was made around the probe-containing tract, using the probe as an internal guide to determine the excision margin and depth. Gentle dissection is performed with blunt Metzenbaum scissors to ensure complete excision of all epithelialized tract and granulation tissue, including the area where the probe is inserted (Fig. 1, Supplementary Video 1). Elevating the probe upward—perpendicular to the skin surface—facilitates easier and safer dissection along the tract. After excision, SIH was preferentially recommended following meticulous hemostasis using electrocautery. Primary closure was performed only in patients who were unable to perform self-dressing or declined SIH. Postoperative alginate and foam dressings were routinely changed and transitioned to lighter, thinner materials as exudate decreased. On postoperative day 1, patients were evaluated for procedure-related complications. Thereafter, wound assessment and dressing changes were performed every 3 to 4 days during the first postoperative week. Subsequently, patients were instructed in self-dressing and followed weekly for wound evaluation.

Fig. 1. Case No. 9. Pilonidal sinus. (A) Preoperative image. (B) Immediate postoperative appearance following lesion excision. (C) Excision of the lesion performed with a probe passed through the sinus tract. (D) Gross pathological specimen demonstrating complete excision of the sinus tract.

A total of 10 patients with histopathologically confirmed pilonidal sinus who underwent sinus tract excision using the above-described technique were reviewed (Table 1). Primary closure was performed in 4 patients; among them, 1 patient developed wound dehiscence at 1 month postoperatively and was subsequently managed with SIH. The remaining 6 patients were treated with SIH without primary closure. In the SIH group, the mean time to complete healing was 38.17 ± 10.95 days. Beginning at 3 weeks, all patients were able to perform self-dressing, with weekly outpatient follow-up. During the SIH period, wound cultures yielded bacterial growth in 3 patients, and systemic antibiotics were administered in 1 case (case 10) in whom delayed wound healing was suspected (Supplementary Fig. 1, which provides serial photographs of patients treated with SIH at different time points). Postoperative pain was tolerable in all patients. Excluding case 10, which was lost to follow-up, telephone follow-up of ≥1 year revealed no evidence of recurrence.

Table 1. Clinical characteristics of patients with pilonidal sinus.

Case No.	Sex	Age	Long-axis length on ultrasonography (cm)	Disease duration (mo)	Previous surgical treatments	Reconstruction method	Wound culture	No. of clinic visits	Time to complete healing (days, mean ± SD)
1	M	26	7.0	12	0	Primary closure	N/A	4	14	14
2	M	18	4.0	24	2	Primary closure	N/A	5	14
3	M	28	7.6	9	0	Primary closure	N/A	6	14
4	M	28	2.5	24	1	SIH	No growth	9	40	38.17±10.95
5	M	24	2.5	48	0	SIH	No growth	20	33
6	M	22	1.7	9	0	SIH	No growth	10	27
7	M	22	5.0	36	1	SIH	No growth	10	50
8	F	21	2.0	9	2	SIH	Escherichia coli	10	25
9	M	18	7.0	12	1	Primary closure + SIH	Escherichia coli, Corynebacterium sp.	17	54
10	M	46	1.8	36	0	SIH	Staphylococcus aureus, Corynebacterium sp.	6	N/A (lost to follow-up)

SD: standard deviation, M: male, F: female, N/A: not applied, SIH: second intention healing.

Our probe-guided core excision technique emphasizes minimal yet complete removal of the sinus tract under direct tract guidance. Probe guidance provides real-time depth/trajectory tactile feedback, which may facilitate accurate identification of the tract and its base. Compared with dye-based delineation, probe guidance avoids staining diffusion and may allow more precise confirmation of the true tract extent. Although no clinically evident recurrence was observed at follow-up, this small retrospective series cannot establish superiority over existing techniques; rather, it supports the value of real-time intraoperative guidance for minimal yet complete tract removal. After complete excision, recurrence may still be influenced by wound tension, residual dead space, local hygiene, hair re-entry, and patient-related factors. Because the excised cavity may extend close to the sacrococcygeal bony plane, primary closure can result in superficial approximation with residual deep dead space, potentially predisposing to fluid accumulation, secondary sinus formation, and recurrence. Wound dehiscence after primary closure in one patient further highlights the need to consider closure-related tension and dead space. Therefore, SIH was preferentially recommended to allow gradual filling of the defect from the base upward, although it requires a longer healing period, careful dressing, and close monitoring for infection⁶. However, reconstruction should be individualized according to wound and patient factors, and this small retrospective series does not establish the superiority of SIH or primary closure. Although flap-based techniques may be effective for large defects where primary closure is not feasible⁷, they require greater surgical expertise and are associated with increased operative complexity, flap-specific complications, and larger scars. Selection of primary closure versus SIH was based on patient preference and ability to perform self-dressing, introducing potential selection bias.

Because all procedures were performed at a single center by a single operator, outcomes may reflect operator- or institution-specific factors. Long-term follow-up conducted primarily by telephone may underestimate subclinical recurrence or minor wound-related complications. In addition, this technique may be less reliable in branching sinus tract networks or in tracts partially obliterated by fibrosis after previous inflammation or surgery, where probe-guided delineation may not identify all diseased components. Nevertheless, our probe-guided core excision technique provides a simple yet detailed and practical approach to complete sinus tract removal, and is expected to be clinically useful in routine practice.

In conclusion, complete sinus tract removal in the management of pilonidal sinus is essential for preventing recurrence regardless of the closure technique, and our probe-guided core excision may provide a practical and reliable approach to achieve this goal.

SUPPLEMENTARY MATERIALS

Supplementary Video 1

A video demonstrating pilonidal sinus excision with step by step commentary on the surgical procedure.

Supplementary Fig. 1

Serial photographs of patients treated with secondary intention healing.