Supplementary Material for: Patterns of Surgical Recurrence in Patients with Hidradenitis Suppurativa

Background: Surgery is an essential part of hidradenitis suppurativa (HS) treatment. Understanding and reducing surgical recurrence are crucial to obtaining the best results in patients’ treatment. Objective: The aim of the study was to characterize surgical recurrences in a cohort of patients with HS treated with wide excision and second-intention healing. Methods: A prospective nested case-control study was conducted. A cohort of patients with HS treated with wide excision and second-intention healing was monitored for 68 weeks. The surgical procedure was classified as case (recurrence) or control (no recurrence). The type of recurrence was classified according to the elementary lesion in tunnel or abscess and inflammatory nodule (AN) recurrence. Sociodemographic and clinical data likely related to recurrence and the type of recurrence were evaluated. Results: Sixty-three patients were included, receiving a total of 82 surgical procedures. The mean age of the patients was 36.18 years, and the surgical site presented a Hurley stage II severity in 79.26% (65/82) of the interventions. Tunnel recurrence was observed in 8.5% (7/82) and AN recurrence in 15.85% (13/82) of the interventions. Obesity was associated with a higher risk of recurrence, for both tunnel and AN recurrence. Hurley III at the surgical site, a history of pilonidal sinus, and higher International Hidradenitis Suppurativa Severity Score System (IHS4) after surgery and at week 68 increased the risk of tunnel recurrence. Conclusion: We propose classifying surgical recurrence based on the elemental type of lesion. Tunnel recurrence could originate in the depth of the surgical scar and could be associated with both surgical site factors and inflammatory load. AN recurrence could originate in the borders of the surgical scar and may particularly benefit from preoperative ultrasound.

背景：外科手术是化脓性汗腺炎（hidradenitis suppurativa, HS）治疗的核心手段之一。深入理解并降低手术复发风险，对于实现患者最佳治疗结局至关重要。
目的：本研究旨在对接受广泛切除术联合二期愈合治疗的化脓性汗腺炎患者队列的手术复发情况进行特征分析。
方法：本研究采用前瞻性巢式病例对照研究设计。对接受广泛切除术联合二期愈合治疗的化脓性汗腺炎患者队列进行为期68周的随访监测。将手术病例分为复发组（病例）与未复发组（对照）。根据复发类型对应的原发性皮损特征，将复发分为窦道型复发与脓肿及炎性结节（inflammatory nodule, AN）型复发。本研究对可能与复发及复发类型相关的社会人口学及临床数据进行了评估。
结果：本研究共纳入63例患者，累计完成82台手术。患者平均年龄为36.18岁，其中79.26%（65/82）的手术部位病变处于Hurley II期。在所有手术中，窦道型复发发生率为8.5%（7/82），炎性结节型复发发生率为15.85%（13/82）。肥胖与窦道型及炎性结节型复发的更高风险均存在相关性。手术部位Hurley III期病变、藏毛窦病史，以及术后及随访至68周时更高的国际化脓性汗腺炎严重程度评分系统（International Hidradenitis Suppurativa Severity Score System, IHS4）评分，均会增加窦道型复发风险。
结论：我们建议根据原发性皮损类型对手术复发进行分类。窦道型复发可能起源于手术瘢痕深处，其发生可能与手术部位相关因素及炎症负荷均存在关联。炎性结节型复发可能起源于手术瘢痕边缘，术前超声检查或可为其带来额外获益。