A Physician's Perspective
This section of our website describes Pudendal Neuralgia by clinicians, for clinicians. This information was drafted, reviewed and approved by the physicians on our Board of Directors. The content was developed using published materials as well as our physicians’ personal research and experience with Pudendal Neuralgia.
Pudendal Neuralgia is a condition whose exact incidence is not known, although PN is thought to be more common than is currently diagnosed. It has been referred to by several names including “Alcock’s Syndrome” and “Pudendal Canal Syndrome.” We prefer Pudendal Neuralgia because it describes the symptoms, which may be caused by an entrapment or a compression or tension problem. It is a general term and it does not refer to specific origins of the symptoms.
A common symptom of pudendal neuralgia is urogenital burning. The pain is increased with sitting and somewhat decreased with standing. Many patients have altered skin sensitivity (both hypo- and hypersensitivity) in the distribution of PN: the genitals, perineum, distal one third of the urethra and the rectum. Due to the vast distribution of this nerve, one, some or all branches of the nerve may be involved and subsequent symptoms will result:
· Urinary hesitancy, urgency, frequency, burning
· Perineal and/or genital pain
· Pain during and/or after bowel movement
· Pain during and/or after intercourse
· Urinary and/or fecal incontinence.
Men with so-called “abacterial prostatitis” or “prostatodynia” may indeed have Pudendal Neuralgia.
Pudendal neuralgia can be caused by various mechanisms. These can be separated into three basic categories starting centrally and moving peripherally:
1. Sacral or radicular type factors causing nerve compression or inflammation at the sacral or nerve root level. Possible examples being benign or malignant tumors and trauma to the area.
2. The pudendal nerve is anatomically vulnerable to compression and entrapment along its course. The two main areas being the interligamentous clamp between the sacrospinous and sacrotuberous ligaments and Alcock’s canal. Most commonly at the level of the falciform process. Patients with anatomical predispositions (i.e. smaller canals, narrow window between ligaments, etc.) or biomechanical abnormalities are more susceptible to compression injuries. Patients may have a silent or asymptomatic compression for an extended period of time. Then, an exacerbating and inflaming factor such as surgery, hematoma, cycling, prolonged sitting, stress and tension-holding patterns, horseback riding, etc. causes entrapment, nerve dysfunction and symptoms.
3. The pudendal nerve is also vulnerable to tension injuries. A variety of factors can put undo tension on the nerve causing it to lengthen beyond its normal limits and result in neural inflammation. Such inciting factors include vaginal childbirth, constipation with repetitive straining to defecate and squatting with heavy weights. Pelvic floor dysfunction, genital prolapse and so-called descending perineum syndrome can also contribute to nerve tension injury. Fixation along the nerve pathway will result in the nerve becoming more likely to be injured with any of the above factors.
The pudendal nerve carries both motor and sensory neurons arising from sacral segments S2, S3 and S4. These fibers join to form the nerve traveling under the piriformis muscle. The nerve then travels caudally into a small space “clamp” between the sacrospinous ligament and the sacrotuberous ligament. The nerve runs underneath the sacrospinous ligament just medial to its attachment at the ischial spine and superior to the sacrotuberous ligament. The nerve then passes ventrally, medially and caudally through the lesser sciatic foramen. The nerve then enters the pudendal canal (Alcock’s Canal) formed by a duplication of the aponeurosis of the obturator internus muscle. At this level, it crosses over the falciform process of the sacrotuberous ligament. During its course, the nerve gives off several branches. The first being the levator branch followed by the inferior rectal branch. Some anatomic variations of course occur. The remaining nerve is the perineal nerve branch (often called the perineal nerve) innervating the perineal skin and superficial muscles. The nerve them terminates in the dorsal penile or clitoral branch. Keep in mind the nerve is a accompanied by the pudendal artery and venous complex during its course.
The exact mechanism of nerve dysfunction and damage is dependent on its etiology. For patients with nerve entrapment and compression, an inflammatory response is engendered. This results in venous stasis, increased vascular permeability and eventually demyelination. This can result in scar formation and in cases of severe injury, permanent nerve damage. For patients with nerve tension injury, the inflammatory effect is not as severe and demyelination is not a factor. However, neuronal function is impaired. For patients with fixation along the nerve’s course, an injury will be more common because the nerve lacks mobility and is more readily stretched. Also, pelvic floor dysfunction itself may cause pain along the pudendal nerve distribution.
History and physical as well as other diagnostic tests will help differentiate between pudendal nerve entrapment versus nerve dysfunction. For patients with pudendal neuralgia, the patient will describe pain or other nerve dysfunction in accordance with the distribution of the pudendal nerve. The patient may or may not give a history of a common triggering factors (i.e. pelvic surgery, trauma, delivery, etc.). Patients will state that sitting increases symptoms and standing decreases symptoms somewhat. On exam, altered skin sensitivity will be noted. Pressure on the pudendal trunk will produce pain (equivalent to Tinel’s sign). This can be performed both transvaginally and transrectally. A pudendal nerve block may produce significant or complete pain relief for several hours to several weeks. The block may be used as a diagnostic tool; resultant pain relief demonstrates at least some of the symptoms are stemming from an inflamed nerve. The block may be performed via the transperineal, transvaginal or transgluteal route with or without radiographic assistance. Finally, electrophysiologic evaluation can help confirm the site of entrapment and the type of nerve damage. The studies consist of EMG testing of the external sphincter, sacral reflex, pudendal nerve terminal motor latency (PNTML) and somatosensory evoked potential studies. In addition to entrapment, pudendal neuralgia can also be caused by compression or tension dysfunctions. On exam, a patient will still present with a positive Tinel's sign and often pelvic floor dysfunction. Specialized physical therapy in conjunction with pudendal nerve blocks can result in significant reductions in pain and can improve function. When the pudendal neuralgia is caused by an actual nerve entrapment, physical therapy and injections alone are often not successful in completely eradicating the problem. In the event conservative management is failing, sacral reflex testing is indicated to confirm or rule out an entrapment. This will determine if the patient requires further conservative management or a surgical decompression.
Medical - Analgesic medications, even those containing narcotics may have limited efficacy for neuropathic pain. Pain modulators such as tricyclic antidepressants and neuroleptics (i.e. Neurontin, Zonegran, etc.) have varied efficacy. Nerve infiltration with a combination of local anesthetic (Lidocaine or Marcaine) combined with steroid (Triamcinolone or Solu-Medrol) or combined with Heparin can be used. Multiple injections (usually 3-5) may be required. Timing intervals vary but 3-6 week interval between infiltration seems reasonable. Success rates also vary widely where between 15-60% are cured or improved with this approach alone.
Lifestyle Modifications – Avoiding activities which worsen the condition is crucial (cycling, sitting, etc.). Sitting pads, especially those designed with cutouts to transmit pressure away from the perineum, can be very helpful.
Physical Therapy - Musculoskeletal dysfunctions can cause pudendal neuralgia as well as other painful pelvic syndromes. Physical therapy is an effective method of minimizing or eliminating the concurrent pain generators that occur when the pudendal nerve is irritated (i.e., pelvic floor hypertonicity and myofascial trigger points, extrapelvic hypertonicity and trigger points, adverse neural tension, sacro-iliac joint dysfunctions, connective tissue restrictions, and faulty neuromuscular recruitment patterns). It is important to acknowledge this interaction between musculoskeletal and neural dysfunction as it is unusual that one exists without the other.
Physical therapists require special training to treat pudendal neuralgia. The therapist should have a strong manual therapy bias and an extensive working knowledge of pudendal neuralgia. The program should emphasize restoring normal length to the pelvic floor (through internal myofascial release) and pelvic floor relaxation techniques. Typically, the shortened pelvic floor/pudendal neuralgia will become symptomatically exacerbated with Kegel exercises and these should be avoided until otherwise instructed by a professional. The program should also include connective tissue mobilization, neural mobilization and a home exercise program.
Surgical - Three main surgical techniques are currently available (worldwide) for nerve decompression. The theory is similar to other nerve decompression procedures performed for nerve entrapments in other regions of the body (i.e. carpal tunnel release). The procedures differ in their approach to the area of entrapment and have never been compared head to head.
Post-Operative Physical Therapy - The above mentioned musculoskeletal dysfunctions can be responsible for pain that persists after a decompression procedure. It is recommended that external physical therapy begin one month post-operatively and that pelvic floor rehabilitation gets initiated at three months.
Sacro-iliac joint dysfunction commonly co-exists with pelvic pain. When the sacrotuberous ligament is severed during decompression, SIJD is a common post-operative complication. Patients typically will have persistent (or ‘new’) pain and pelvic dysfunction. This situation is correctable through proper stabilization techniques: through physical therapy in less involved circumstances and through proliferative therapy and physical therapy in more severe circumstances..
Future research will be directed to optimize the blending of surgical and non-surgical therapy. Postoperative nerve inflammation leads to prolonged recovery times in many patients. Adjuvant therapies could be tried at the time of surgery to decrease this phenomena. Perhaps more direct comparisons of surgical and non-surgical treatments could be made.
A completely new therapy of electronic nerve modulation also holds some promise to treat this condition. This may be particularly helpful for patients who fail surgical therapy.
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Robert R, et al, Decompression and Transposition of the Pudendal Nerve in Pudendal Neuralgia: A Randomized Controlled Trial and Long-Term Evaluation. European Urology, 2005, 47; 3:403-408.
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