Probe-Guided Intersphincteric Lateral Internal Sphincterotomy: A Modified Approach for Chronic Anal Fissures

BACKGROUND: Lateral internal sphincterotomy (LIS) is a well-established treatment for chronic anal fissures. Building on this, probe-guided intersphincteric LIS employs a probe-assisted paramedian incision to integrate fissurectomy with sphincterotomy, while prophylactically addressing potential crypt pathology. This anatomically guided, standardized approach broadens its applicability to both typical and complex fissures, while remaining safe, reproducible, and technically accessible, particularly for less experienced surgeons. IMPACT OF INNOVATION: This modified technique introduces the following three key advancements:1) Anatomic precision: a rigid probe inserted through the intersphincteric groove directs dissection toward dentate crypts; 2) Cryptoglandular excision: prophylactically excising potentially infected crypts corresponding to the fissure apex; 3) Regional perfusion optimization: the paramedian incision creates drainage-optimized wounds that improve local vascularity and reduce the keyhole deformity risk. Applicable to complex or refractory fissures complicated by fistula or anal stenosis, this enables single procedure multimorbidity resolution. TECHNOLOGY MATERIALS AND METHODS: The procedure is performed under local anesthesia with intravenous sedation and the patient is positioned in the right lateral decubitus position, surgeons created a 3-mm entry at 7:00 through the intersphincteric groove, and angled the probe 20° toward the dentate crypts. Digital guidance enabled precise mucosal penetration and layered sphincterotomy, with concurrent excision of hemorrhoids/hypertrophic papillae forming V-shaped defects. PRELIMINARY RESULTS: The procedure averaged 11 ± 2.3 min with <5 mL blood loss. Postoperative pain was mild (VAS 0–2). Healing was achieved in 96.4% (159/165) within 4 weeks, with four (2.4%) requiring drainage revision (healed by 3 months). Two recurrences (1.2%) resolved after secondary fissurectomy. No incontinence, stenosis, or keyhole deformities occurred. CONCLUSIONS AND FUTURE DIRECTIONS: Probe-guided modified LIS provides a controlled, reproducible sphincterotomy, with a low complication rate and favorable outcomes even in complex fissures. See New Technology Report Video .