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

Lateral internal sphincterotomy is a well-established treatment for chronic anal fissures. Building on this, probe-guided intersphincteric lateral internal sphincterotomy uses 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.

This modified technique introduces the following 3 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; and 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 approach enables single-procedure multimorbidity resolution.

The procedure is performed under local anesthesia with intravenous sedation, and the patient is positioned in the right lateral decubitus position. The surgeons created a 3-mm entry at 7 o'clock 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.

The procedure averaged 11 ± 2.3 minutes and resulted in <5 mL of blood loss. Postoperative pain was mild (visual analog scale 0-2). Healing was achieved in 96.4% of patients (159/165) within 4 weeks, with 4 (2.4%) requiring drainage revision (healed by 3 months). Two recurrences (1.2%) resolved after secondary fissurectomy. No incontinence, stenosis, or keyhole deformities occurred.

Probe-guided modified lateral internal sphincterotomy provides a controlled, reproducible sphincterotomy, with a low complication rate and favorable outcomes even in complex fissures. See New Technology Report Video .