Introduction: Not Just a “Trapped Nerve”

Pudendal neuralgia (PN) is a chronic neuropathic pain condition affecting the distribution of the pudendal nerve. It is increasingly recognised as a distinct clinical entity, yet it remains frequently misdiagnosed, misunderstood, and undertreated.

While pudendal nerve irritation or entrapment can occur, it is crucial to understand that in many patients pudendal neuralgia does not exist as an isolated mechanical compression. Rather, it often forms part of a broader pelvic pain syndrome, involving muscular, biomechanical, visceral, neurological and psychological components.

This complexity explains why:

• Imaging is often normal
• Surgery is not always effective
• Isolated injections may give only temporary benefit
• A purely structural explanation is insufficient

Successful management therefore requires a structured, multidisciplinary and anatomically precise approach.

The Nantes Criteria – Diagnostic Foundation

Diagnosis of pudendal neuralgia is primarily clinical and guided by the internationally recognised Nantes Criteria.

Essential Inclusion Criteria

All five should be present:

• Pain in the anatomical territory of the pudendal nerve (from anus to penis or clitoris)
• Pain predominantly worsened by sitting
• Pain does not wake the patient at night
• No objective sensory loss on examination
• Pain relieved by diagnostic pudendal nerve block

Exclusion Criteria

Features that make the diagnosis unlikely:

• Pain exclusively coccygeal, gluteal, pubic or hypogastric
• Pure pruritus
• Exclusively paroxysmal pain
• Imaging abnormalities that explain symptoms

These criteria remain the gold standard and form the backbone of specialist assessment.

Distribution of Pain in Pudendal Neuralgia

The pudendal nerve supplies sensory innervation to:

• Perineum
• External genitalia
• Anal canal and perianal skin
• Distal urethra
• Parts of pelvic floor musculature

Typical Pain Characteristics

Patients often describe:

• Burning
• Electric shock–like sensations
• Deep aching
• Pressure or “foreign body” sensation
• Hypersensitivity to clothing

Pain is frequently unilateral but may be bilateral.

Why Can Pain Radiate to the Legs?

Although the pudendal nerve itself is a perineal nerve, radiation into the buttock, posterior thigh or even leg can occur due to several mechanisms:

Shared Sacral Roots (S2–S4)

Pudendal nerve fibres originate from sacral roots that also contribute to other pelvic and lower limb neural structures. Irritation at the sacral plexus level may produce overlapping symptoms.

Deep Gluteal and Piriformis Interaction

The pudendal nerve exits the pelvis near the piriformis and close to the sciatic nerve. Deep gluteal spasm or sacral plexus irritation may create mixed symptom patterns.

Central Sensitisation and Pain Amplification

In chronic cases, central pain processing may expand the perceived pain territory beyond the anatomical distribution.

This explains why pudendal neuralgia may sometimes mimic sciatica, sacroiliac pathology, or posterior hip disorders.

Contributory and Overlapping Factors (Integrated Perspective)

Pudendal neuralgia frequently coexists with, or is maintained by, multiple interacting factors:

• Chronic pelvic floor hypertonicity can compress the nerve at the ischial spine or within Alcock’s canal, reduce neural glide, and perpetuate neuropathic irritation.
• Persistent constipation and repetitive straining increase intrapelvic pressure and mechanical stress on the nerve while simultaneously driving pelvic floor overactivity.
• Prior surgeries such as episiotomy, hysterectomy, prolapse repair or haemorrhoid procedures may lead to scar tethering and altered biomechanics.
• Deep gluteal pathology, including piriformis syndrome, may contribute to sacral plexus irritation.
• Over time, chronic nociceptive input may induce central sensitisation, amplifying pain perception and expanding symptom distribution.

The concept of pudendal neuralgia as part of a broader pelvic floor pain syndrome has been described in the literature and holistic approaches are strongly supported in chronic pelvic pain management. Recognising these overlapping contributors is essential — failure to address them limits treatment success.

Imaging and Investigations

MRI is primarily used to:

• Exclude tumour or structural lesions
• Evaluate ischiorectal fossa
• Identify atypical presentations

Imaging supports diagnosis but does not replace clinical criteria.

Advanced Interventional Treatments at Pain Spa

Interventional treatments are considered when conservative management and physiotherapy have not provided sufficient relief. These procedures are most effective when guided by precise anatomical diagnosis and careful patient selection.

Pudendal Nerve Block (Diagnostic and Therapeutic)

A pudendal nerve block plays a pivotal role in both confirming diagnosis and initiating treatment. Relief following a correctly placed block satisfies one of the essential Nantes criteria and supports pudendal-mediated pain. Published data report high short-term response rates, often exceeding 70–90% in appropriately selected patients.

Beyond diagnosis, the block may:

• Interrupt a pain cycle
• Reduce neurogenic inflammation
• Provide a window for physiotherapy
• Identify candidates for further neuromodulation

Why Ultrasound Guidance Matters

The pudendal nerve lies adjacent to critical vascular structures and deep pelvic ligaments. Blind or landmark techniques risk inaccuracy. At Pain Spa, blocks are performed under real-time ultrasound guidance, allowing:

• Direct visualisation of anatomical landmarks
• Identification of internal pudendal vessels
• Precise needle placement
• Reduced complication risk
• Improved reproducibility

This precision is essential in a nerve with complex and variable anatomy.

Pulsed Radiofrequency (PRF) of the Pudendal Nerve

When nerve blocks provide temporary relief but pain recurs, pulsed radiofrequency (PRF) offers a longer-acting neuromodulatory option. PRF delivers controlled pulsed electrical energy at 42°C. Importantly:

• It does not thermally destroy the nerve
• It preserves motor and sensory function
• It modifies abnormal pain signalling

Clinical literature demonstrates meaningful pain reduction in refractory cases, and systematic reviews describe promising outcomes in selected patients.

PRF is considered safer than continuous radiofrequency because it avoids neurodestructive temperatures.

Why Real-Time Ultrasound Is Crucial

Accurate localisation of the pudendal nerve is essential for effective neuromodulation. At Pain Spa, PRF is performed under real-time ultrasound guidance, ensuring:

• Exact targeting of the nerve
• Avoidance of vascular structures
• Optimal electrode positioning
• Enhanced procedural safety

In experienced hands, PRF can significantly improve sitting tolerance, reduce medication burden, and restore function.

Ganglion Impar Block

The ganglion impar represents the terminal sympathetic ganglion supplying nociceptive fibres to the perineum and distal pelvic structures.

In patients with:

• Midline perineal pain
• Coccygodynia
• Sympathetically maintained pelvic pain
• Persistent burning pain

A ganglion impar block may provide significant benefit. This intervention is particularly useful when pain has mixed somatic and sympathetic characteristics.

Surgical Decompression

Surgical decompression is reserved for carefully selected patients who meet strict diagnostic criteria and fail conservative and interventional therapy. Expert consensus emphasises cautious selection and multidisciplinary assessment before proceeding. Surgery is not first-line and should not be considered without structured evaluation.

Conclusion

Pudendal neuralgia is a complex, multifactorial pelvic pain condition. While it may begin as a peripheral neuropathic irritation, it often evolves into a broader pelvic pain syndrome involving muscular, biomechanical and central nervous system components.

Precise diagnosis using the Nantes criteria, recognition of contributory factors, and the use of advanced real-time ultrasound-guided interventional treatments are essential for optimal outcomes.

At Pain Spa, the combination of anatomical expertise, ultrasound precision, and holistic pain management allows for a structured, evidence-based approach to this challenging condition.