Somatic nerves can be sensitive nerves, motor nerves or nerves that contain both sensitive and motor nerve fibers (mixed nerves). Sensory nerves transmit information from peripheral tissues (skin, muscles, bone-periosteum, etc.) to the central nervous system. Through this type of system (the afferent nervous system) pain is transmitted to the cerebral cortex. Motor nerves, or the efferent nervous system, transmit information from the central nervous system to tissues – striated muscles – and are responsible for voluntary motor acts, such as locomotion, writing, speaking, etc.

Pelvic pain, extremely frequent in both women and men, associated with lumbar pain, is most often determined by irritation of the pelvic somatic nerves, at various levels – nerve roots, nerve plexuses, terminal nerves (sensitive, motor).

The most important somatic nerves in pelvic pathology are represented by: genitofemoral nerve, obturatory nerve, gluteal nerves (superior/inferior), femoral nerve, pudendal nerve, sciatic nerve. In addition to the pathology of these peripheral somatic nerves, neuropelveology also deals with the pathology of the lumbosacral plexus (L5/S1) or sacral roots (S2/S3/S4).

Genitofemoral nerve – (T12)/L1/L2 – is a sensitive nerve (in men it also has a motor function – the cremasteric reflex), has two terminal branches and sensitively innervates the root of the thigh, the anterior labial region, the scrotal region (in men), the clitoridian region; it can be damaged during abdominal surgeries (appendectomy, transverse laparotomy – ex – cesarean section, treatment of inguinal/femoral hernias), as well as following trocarizations in laparoscopic surgeries.

Damage/irritation of this nerve can produce paresthesia/pain in the inguinal region, at the labial (anterior region), clitoral level, as well as severe dyspareunia.

Obturatory nerve – L2/L4 – a mixed nerve that innervates the striated adductor muscles of the thigh, as well as receiving sensory information from the inner (medial) surface of the thigh.

This nerve can be damaged during oncological surgeries – pelvic lymphadenectomy or in pelvic floor reconstructive procedures.

Also, irritation (neuralgia) of the obturatory nerve can occur in chronic inflammatory diseases (including pelvic endometriosis), in pelvic oncological diseases – obturatory adenopathies, as well as in other non-specific diseases (e.g. sarcoidosis)

Gluteal nerves (superior, inferior) – leave the pelvis at the level of the inchiatic foramen, superior (L4/L5/S1) and inferior (L5/S1/S2) to the lumbo-sacral plexus (sciatic nerve). They are mixed somatic nerves that innervate the gluteal muscles. It leaves the pelvis at the level of the greater sciatic notch, superior and inferior to the lumbosacral plexus.

These nerves can be damaged during orthopedic interventions, during the excision of endometriotic lesions at this level, as well as during extended pelvic lymphadenectomy. These nerves can also be directly affected by deep pelvic endometriosis of the sciatic nerve.

Femoral nerve – represents the largest nerve from the lumbar plexus (L2/L3/L4) and is a mixed somatic nerve that has a particularly important role in locomotion and also in the sensitivity of the pelvic limb (thigh, knee, calf, foot), being complementary/antagonistic to the sciatic nerve.

From the spinal level, the femoral nerve has a path among the muscle fibers of the iliac and psoas muscles (ilio-psoas) and leaves the pelvis at the level of the femoral muscular lacuna, lateral to the femoral vessels. It can be affected during the dissection/resection of retroperitoneal tumors/sarcomas at this level or during hernia repair.

Pudendal nerve – represents a mixed nerve that has a very sinuous path at the pelvic and perineal level. It represents the main perineal nerve that sensitively innervates the vulvar and perineal region; it also has efferent fibers to the external anal and external urethral sphincters (particularly important role in defecation and urination), as well as vegetative fibers*.

It is formed from the level of the sacral roots S2/S3/S4, goes laterally into the pelvis, leaves the pelvis at the level of the greater ischiatic notch, posterior to the ischio-coccygeus muscle and the sacro-spinous ligament; then, it enters the Alcock canal and branches into the 3-4 terminal nerves: inferior rectal nerve, perineal nerves (superficial/deep) and the dorsal nerve of the penis/clitoris.

Compression of the pudendal nerve/its branches may appear at the level of 4 different levels:

I. Inferior to the piriformis muscle

II. Between the sacro-spinous and sacro-tuberous ligaments – the most common cause of pudendal nerve compression

III. At the level of the Alcock canal

IV. At the level of the terminal branches

The most common causes of compression/irritation of the external pudendal nerve are represented by vasculo-nervous entrapment, trauma during vaginal births, chronic constipation, direct trauma, prolonged sitting (office work, driving, cycling), radiotherapy, sports that produce repeated and/or forced flexion of the thigh on the abdomen

Pudendal neuralgia is one of the most well-known pelvic neurosurgical pathologies, produced following trauma/compression of the external pudendal nerve.

Symptomatology of pudendal neuralgia is dominated by urinary symptoms (polakiuria, dysuria – similar to urinary tract infections), vaginismus (severe dyspareunia, permanent sensation of an intravaginal ‘foreign body’), rectal disorders (rectal tenesmus, dyschesia).

Most of the time these symptoms worsen while sitting and improve when the patient is lying down or even standing up.

The diagnosis is mostly a clinical one – a detailed history, with local and general clinical examination being sufficient most of the time. Pelvic MRI examination can highlight a possible cause of pudendal neuralgia (pelvic tumors, endometriosis, aberrant/dilated pelvic veins, hypertrophied muscles – piriformis), and anesthetic block at the Alcock canal level establishes the diagnosis with certainty when the compression is at levels III/IV.

When conservative treatment has no effect or does not sufficiently relieve pain, surgical treatment is required – neurolysis of the pudendal nerve with its decompression (dilated veins, fibrotic tissue, muscle tissue).

The lumbosacral trunk (L5/S1), part of the sciatic nerve with which it continues at the exit from the pelvis, is located at the level of the lumbosacral space, deep and lateral to the external iliac vessels, medial to the psoas muscle.

It represents the most frequent localization of vasculo-nervous conflict. (Prof. M. Possover). During dissection of the lumbo-sacral space and lumbo-sacral trunk, we encounter most often, in patients with specific symptoms (symptoms of lumbo-sacral sciatica), dilated abherrant vessels that compress/irritate the nerve roots, especially in the standing position.

Surgical interventions at this level, after excluding a neurosurgical pathology, with sectioning of the dilated veins, have a spectacular effect on the symptomatology, with the disappearance of pelvic and lumbar pain (radiating to the thigh) from the first postoperative day.

The sciatic nerve (L4/L5/S1/S2/S3) – represents the most important mixed somatic nerve (and the longest in the human body) at the level of the sacral plexus. It leaves the pelvis at the level of the greater sciatic notch, lateral and superior to the external pudendal nerve.

The sciatic nerve can be compressed/infiltrated by deep pelvic endometriotic lesions, thus producing lumbo-sciatica phenomena (differential diagnosis with lumbar neurosurgical pathology).

Most often, endometriosis produces compression of the S2/S3 sacral roots by extension of lesions at the level of the deep parametrium; often, in these cases there is ureteral and rectal involvement, this surgeris being some of the most complex in pelvic surgery. Less often, ‘sciatica endometriosis’, lesions are isolated, infiltrating nerve fibers at the level of the lumbosacral plexus. In these cases, locomotor disorders and pain in the ipsilateral pelvic limb are the dominant symptoms.

Surgical treatment

When the etiological diagnosis is certain and conservative treatments (anti-inflammatory medication, neurological medication, sometimes psychiatric medication – antidepressants, physiotherapy) are ineffective or cannot be tolerated by patients, minimally-invasive surgical treatment (conventional laparoscopy, robotic surgery) remains the only option.

Surgical treatment of pelvic neurosurgical pathology is represented by extensive neurolysis, associated with endometriosis excision, sectioning of dilated pelvic vessels, muscle fibers, fibrotic scar tissue, resection of the alloplastic meshes used in the reconstruction of the abdominal wall or pelvic floor.

Minimally invasive surgery offers very good visualization of the nervous structures, a very meticulous and careful hemostasis, as well as a very delicate manipulation of the pelvic nerves (most often very thin).

More recently, robotic surgery offers additional advantages to these surgical techniques: a much better precision of the surgical act (absence of human tremor), which is essential in these deep pelvic interventions, a more delicate manipulation of the pelvic nerves.

From our experience with this type of pathology, we have observed a faster/better recovery of patients after robotic surgery.