Pudendal Neuralgia. Decompression of the pubic nerve. Risks and side effects

Pudendal neuralgia is an extremely frequent urological, gynecological, and neurological pathology, but extremely underdiagnosed

The most common symptoms of pudendal neuralgia are:

• urinary disorders – similar to urinary infections which are often confused with and improperly treated; most of the time, PN is diagnosed as ‘interstitial cystitis’, an extremely rare pathology that definitely requires histopathological confirmation.
• vaginismus – most of the time patients cannot have a normal sexual life
• digestive disorders – especially in the lower digestive tract – constipation, rectal tenesmus
• perineal pain, pelvic pain
• pain/paresthesia at the level of the internal face of the thighs, at the level of the buttocks

Most of the time, these symptoms are aggravated by effort, by sitting down, and relieved by orthostasis (standing) and clinostat (lying horizontally).

The patients we meet in our medical practice, most of the time do not present the entire clinical picture, but only a part of the symptoms; the most common symptoms are urinary (dysuria, pollakiuria) and vaginal – vaginismus (extreme pain during sexual intercourse, pain during gynecological consultations).

After many erroneous diagnoses and consequent treatments, patients are “encouraged” to seek psychiatric help. This is where the dependence on psychotropic and opioid medication comes from, which is sometimes the only remedy for these patients. After months/years of drug medication, patients become addicted and they develop a tolerance. At this point, the only therapeutic option is surgical intervention together with pain therapy (complementary therapy).

Unfortunately, it seems that as the pain becomes chronic, the pubic nerve(s) is more severely affected and the surgical intervention does not always have the desired effect.

In order for the surgical intervention to be effective, the diagnosis of pudendal neuralgia (uni/bilateral) must be correct. The best way to set this diagnosis, apart from the clinical examination ( which is extremely important), another test is the anesthetic block of the pubic nerve at the level of the Alcock canal.

This surgical intervention is not a simple one. The surgical team must be trained in minimally invasive surgery (laparoscopic or robotic). The dissection of pelvic vessels and nerves (especially at this level) is a very delicate surgical act due to the extremely narrow space in which the surgeon operates.

We recently performed this intervention with the DaVinci robot, which made a real difference considering the approach/visualization as well as performing a finer dissection of the nervous structures. The pubic nerve is a sensitive nerve at the pelvic/perineal level, with a thickness that varies between 2 and 10 mm, which makes its dissection (decompression) almost impossible without damaging some nerve fibers.

With the help of robotically assisted laparoscopy, this is minimized through the highly enlarged three-dimensional image and the articulated instruments, which help us to dissect the pudendal nerve and vessels without causing injuries. As such, the postoperative pain is significantly decreased and the recovery is much faster.

*The surgical technique is very complex and can be performed only by surgeons with experience in pelvic surgery (gynecologists, urologists, general surgeons). After penetrating the obturator fossa, with dissection of the obturator vessels and the obturator nerve (not always necessary), the endopelvic fascia that covers the internal obturator muscle, the iliococcygeus muscle (part of the levator anal muscles) is dissected. After sectioning a few muscle fibers, decompression of the external pubic vascular-nerve block is performed by sectioning the connective fibers of the sacrospinous ligament. At this point, the pudendal nerve is no longer under tension (it is ‘released’), it is medial and superior to the sciatic spine, and the pudendal artery is pulsating.These are the most important signs of a correctly executed surgery.

Unfortunately, when handling very fine, millimetric structures (sometimes on the order of microns) preservation of all the vascular and nervous structures is not always possible at this level. That’s why this type of surgery sometimes has adverse effects like lingering pain (especially at the perineal or vaginal level), digestive disorders (constipation, rectal tenesmus, lack of defecation sensation), and urinary disorders (decreased sensation of urinating). But, most frequently, in the immediate postoperative period, patients complain of a ‘numbness’ sensation in the vagina, and perineum, which usually means the success of the surgical intervention.

The adverse effects of this type of surgery (it actually represents neurosurgery of the peripheral nerves) can be:

• unilateral/bilateral pelvic, perineal pain (radiated pain)
• pain at the root of the thigh – most often on the inner side of the thigh
• pain in the iliac fossa
• intestinal transit disorders – most often transitory constipation, rectal tenesmus
• paresthesia at the level of the area innervated by the external vagus nerve: numbness, stinging
• pain/difficulties in defecation, radiating to the thigh, calf, leg
• difficulty urinating or burning sensation when urinating, bladder tenesmus

It is very important to mention that all these symptoms are transitory. They can last from a few days to a few weeks or months, but sometimes, a full recovery can be extended for longer periods of up to a year.

During the recovery period, apart from the specific medication, which is sometimes not easy to tolerate, an important role is played by physiotherapy dedicated to this pathology. Sometimes, in the immediate or late postoperative period, after this particular type of surgery, the patients inform us, to our joy and theirs, of the disappearance of pain in the lumbar areas or in the shoulder, something that does not necessarily have medical logic.