What are the risks and outcomes of pudendal nerve branch resection surgery in a patient with a history of anorectal surgery and neurogenic symptoms?

Pudendal Nerve Branch Resection Surgery: Risks, Approach, and Outcomes

For patients with neurogenic symptoms following anorectal surgery, pudendal nerve surgery via either transgluteal or transperineal approaches offers substantial symptom relief (66-86% success rates), though untreated anxiety/depression predicts failure regardless of surgical technique. 1, 2

Surgical Approaches and Terminology

The procedure is called pudendal nerve decompression or pudendal neurolysis, with resection reserved specifically for traumatic neuromas. 1 Two main surgical corridors exist:

Posterior (Transgluteal) Approach

• Indicated when: Rectal pain is present as part of the symptom complex 1
• Technique: Surgical release of the pudendal nerve from the infrapiriformis foramen to Alcock's canal through the gluteal region 2
• This remains the reference standard technique 2

Anterior (Inferior Pubic Ramus) Approach

• Indicated when: Symptoms exclude rectal pain 1
• Alternative routes: Transvaginal or transperineal approaches have been described 2

Endoscopic Transperineal Approach

• Newest technique: "Operative pudendoscopy" provides close-up visual control of each decompression step 3
• Mean operating time: 50.3 minutes per side 3
• Hospital stay: Average 2.1 days 3

What the Surgery Entails

The procedure involves complete decompression of the pudendal nerve from distal branches to the sacral foramina, including division of the sacrospinous ligament under direct visualization. 3 The surgeon distinguishes between:

• Neurolysis/decompression: For nerve compression without neuroma formation 1
• Neuroma resection: When trauma has created a discrete neuroma 1

No difference in outcomes exists between resection versus neurolysis approaches when appropriately selected. 1

Surgical Risks and Complications

Major Complications

• Severe hemorrhage: Inferior gluteal vessel laceration requiring arterial embolization (reported in 1/113 patients with endoscopic approach) 3
• Infection with tissue devitalization: Can occur affecting transposed muscle if reconstruction is performed 4

Neurological Risks

• Progressive neurogenic damage: Postanal repair procedures can paradoxically worsen pudendal nerve terminal motor latency and increase fiber density in the external anal sphincter, potentially causing the operation itself to contribute to pelvic floor denervation 5
• Nerve plexus damage: Lower risk with perineal approaches compared to abdominal approaches for anorectal procedures 6

Common Perioperative Issues

• Infection, pain, bleeding: Standard surgical risks 6
• Sexual dysfunction: Lower rates with perineal versus abdominal approaches 6

Surgical Outcomes

Success Rates by Experience Level

The surgeon's learning curve dramatically impacts outcomes: 1

• First year: Lower success rates
• Second year: Significantly better results (p < 0.0001) 1
• Third year: Further improvement (p < 0.04), with 86% achieving excellent results and 14% achieving good results 1

Overall Efficacy

• Traditional transgluteal approach: 66-80% of patients improved, validated by prospective randomized protocol 2
• Endoscopic transperineal approach: Pain VAS dropped from 7.2 to 4.5 (p < 0.0001) with significant improvement in urinary, sexual, and anorectal symptom scores 3
• Mean follow-up: 14.3 months for peripheral nerve approach study 1, minimum 24 months for endoscopic series 3

Functional Improvements

• Pathological perineal descent: Reduced from 1.81 cm to 0.77 cm postoperatively (p < 0.0001) 3
• Sexual symptoms: Significant reduction in sexual arousal syndrome, dyspareunia, and cystalgia 3
• Sphincter function: Purposeful contraction achievable without special training when nerve anastomosis performed 4

Critical Predictors of Failure

Untreated anxiety or depression correlates with surgical failure regardless of approach (p < 0.002). 1 This represents the single most important modifiable risk factor and must be addressed before proceeding with surgery.

No Difference in Outcomes Between:

• Men versus women 1
• Anterior versus posterior approach 1
• Neuroma resection versus neurolysis 1

Key Clinical Pitfalls

The "traditional" posterior transgluteal nerve decompression fails in an unacceptably high percentage of patients when performed without attention to specific pudendal neuroanatomy and pathophysiology. 1 Success requires:

• Site-specific surgical planning: Match the approach to which pudendal nerve branches are involved 1
• Distinguish compression from neuroma: Different pathophysiology requires different surgical strategy 1
• Surgeon experience: Outcomes improve substantially with experience 1
• Psychiatric comorbidity management: Address anxiety/depression preoperatively 1

This surgery should only be considered after failure of medical management and pelvic floor therapy. 1