Nerve Injury Risk with LigaSure Hemorrhoidectomy
LigaSure hemorrhoidectomy causes minimal nerve damage to surrounding tissues, with significantly less lateral thermal spread than conventional diathermy, though histopathological studies document measurable thermal injury extending beyond the immediate treatment zone.
Mechanism of Reduced Nerve Injury
LigaSure technology uses high-frequency current with active feedback control over power output, which produces minimal thermal spread and limited tissue charring compared to conventional electrocautery techniques 1.
The device seals blood vessels and tissue into a "wafer-thin seal" with minimal lateral spread of either thermal or electrical energy, reducing collateral damage to adjacent structures including nerve fibers 2.
Direct Evidence of Nerve Preservation
A 2018 comparative study using histopathological examination found no significant difference in the number of peripheral nerve fibers damaged between LigaSure and conventional hemorrhoidectomy, despite LigaSure producing more measurable lateral thermal damage on microscopy 3.
This apparent paradox—more thermal spread but equivalent nerve fiber counts—suggests that while LigaSure creates a wider zone of thermal effect, the actual functional nerve injury remains comparable to conventional techniques 3.
Clinical Manifestations of Nerve Preservation
Long-term follow-up (36–37 months) demonstrates that LigaSure hemorrhoidectomy preserves internal anal sphincter thickness better than conventional diathermy (2.5 mm vs 1.88 mm, P=0.005), suggesting less traumatic dissection and reduced injury to the neuromuscular complex 4.
Patients treated with LigaSure show improved rectal urge sensation at long-term follow-up (284 mL vs 173 mL, P=0.08), indicating better preservation of sensory nerve pathways in the anal canal 4.
Incontinence rates are equivalent between LigaSure and conventional techniques (2–12% overall), with no increase in sphincter defects documented by endoanal ultrasound, confirming that the minimal thermal spread does not translate into clinically significant nerve injury 5, 4.
Quantifying the Thermal Damage Zone
Histopathological analysis reveals that LigaSure creates statistically more lateral thermal damage on microscopic examination (P<0.001), but this increased thermal zone does not correlate with worse pain scores, complications, or functional outcomes 3.
The thermal injury zone remains confined enough to avoid clinically relevant nerve dysfunction, as evidenced by equivalent Visual Analog Scale pain scores across all postoperative time points when compared to conventional diathermy 3.
Pain as a Surrogate Marker for Nerve Injury
LigaSure hemorrhoidectomy produces significantly lower pain scores throughout the first postoperative week (P<0.001), suggesting less nociceptive nerve stimulation from tissue trauma 6, 2.
The median pain score on postoperative day 1 is significantly lower with LigaSure (WMD -2.07,95% CI -2.77 to -1.38), and this benefit persists through day 7, indicating reduced acute nerve injury 1.
By postoperative day 14, pain differences disappear (WMD -0.12,95% CI -0.37 to 0.12), consistent with resolution of temporary nerve irritation rather than permanent nerve damage 1.
Critical Caveats and Pitfalls
While LigaSure causes less immediate nerve-related pain, the number of excised hemorrhoidal bundles correlates positively with pain intensity regardless of technique, meaning aggressive excision will cause more nerve trauma even with LigaSure 3.
The technique requires proper application at least 2 cm proximal to the dentate line to avoid severe pain from somatic sensory nerve stimulation, just as with conventional hemorrhoidectomy 7.
Sphincter defects occur in up to 12% of patients after any hemorrhoidectomy technique when excessive retraction or dilation is performed, emphasizing that surgical technique—not just the energy device—determines nerve injury risk 5.
Avoid assuming LigaSure eliminates all nerve injury risk: incontinence rates remain 2–12% across all techniques, reflecting unavoidable trauma to the internal anal sphincter's autonomic nerve supply during hemorrhoidal excision 5, 4.