Posterior Nerve Entrapment

Pelvic pain can often involve adverse neural tension. The hip and pelvic nerves wrap around like spaghetti, making diagnosis and treatment difficult. Is the pain driver boney, capsular, muscle or neurovascular? Luckily, impingement and labral tears are fairly easy to diagnosis. Nerve entrapment can be a little bit tricky to diagnosis and treat. Part of being a good pelvic floor physical therapist is appropriately diagnosing and then partnering with patients to treat symptoms, pain, and movement dysfunction.

The authors of this study focused on hip, so this blog focuses on sciatic and pudendal nerve entrapment in the athletic population. Nerve entrapment occurs when the normal slide and glide is limited. That can be from any structure in the pelvis and hip region that cause strain or compression on the nerves in the area. Often patient’s descriptions of pain can be the first sign with complaints of ‘burning’, ‘sharp’, or changes in sensation. Evaluation for changes in reflexes and motor function are helpful. Other signs of nerve entrapment are tenderness to palpation and reproduction of pain with movements that elongate the nerve. Medical management to confirm diagnosis include nerve blocks, and diagnostic imaging, and nerve conduction velocity tests.

Specific locations of pain can help determine where the nerve is being squished. The sciatic nerve (L4-S3) can be entrapped as it passes between the piriformis and deep hip rotators. This often presents with a history of trauma to the gluteal area and limited sitting tolerance (>30 minutes). As the sciatic nerve moves down it can have ischiofemoral impingement, when the nerve gets compressed between lateral ischial tuberosity and greater trochanter at level of quadratus femoris muscle. This will often present as pain during mid- to terminal-stance during walking. Then, once the sciatic nerve clears the pelvis it can become entrapped by the proximal hamstring. There can be hamstring trauma in the history, and possible partial avulsion or thickening of the hamstring may entrap the sciatic nerve.

The pudendal nerve (S2-S4) can become entrapped in several areas and symptoms often include pain medial to the ischium and can include genital regions for all genders, perineum, and peri-rectal regions. The most common areas consist of the space between the posterior pelvic ligaments (sacrospinous and sacrotuberous) and the obturator internus muscle. History often includes bike riding, and a common complaint is pain with sitting, except a toilet seat.

Differential diagnosis for posterior nerves physical examination can include the following tests:

Sciatic Nerve

• Seated palpation: where the clinician palpates the subgluteal space (between sacrum and deep hip rotators), ischial tuberosity and hamstring attachment, and in the area medial to ischial.
• Seated piriformis stretch - involved lower extremity is adducted and internally rotated while palpating posterior hip region.
• Active piriformis - resisted lateral abduction and external rotation while palpating posterior hip region.
• Ischiofemoral impingement: the involved is placed in extension with adduction and external rotation
• Active knee flexion: this test is done seated with knee at 30° and 90° flexion. Clinician palpates ischial canal while providing knee flexion resistance for 5 seconds in both positions.

Pudendal Nerve

• Palpation around sciatic notch, region medial ischium
• Internal palpation for obturator internus tenderness
• Internal palpation of alcocks canal

Consertative treatment including physical therapy can be helpful. Manual therapy including nerve glides and soft tissue mobilization. Nerve mobilizations require anatomical nerve pathway knowledge. Mobilizing the nerves is thought to improve blood flow within and around the nerve, decrease adhesions, and also may affect central sensitivity. Soft tissue mobilization is geared towards positively affecting scar tissue and encouraging movement that may be restricting neural movement.

Therapeutic exercises for strengthening and stretching are also helpful, however use caution to avoid aggressive stretching as it may aggravate nerves. Exercises to promote load transfer through the pelvis and lower extremities can be helpful. The authors also suggest lower extremity passive PNF (proprioceptive neurofacilitation) diagonal movements. The authors also suggest aerobic conditioning, cognitive behavioral therapy, and for the chronic pelvic pain population, pelvic floor muscle training that does not provoke symptoms.

When conservative treatment including injections produces limited results, surgical treatments are often the next step. Often surgeries where the nerves are decompressed, neurolysis, or removed, neurectomy can be helpful.

To learn more nerve assessment and treatment techniques, join Nari Clemons, PT, PRPC in her course Sacral Nerve Manual Assessment and Treatment in Tampa, FL this December 6-8, 2019!

Martin R, Martin HD1, Kivlan BR 2.Nerve Entrapment In The Hip Region: Current Concepts Review.Int J Sports Phys Ther. 2017 Dec;12(7):1163-1173.