1. Nerve Entrapment Syndromes
Kaan Yaltirik, MD

2. The brain and spinal cord receive and send information through muscles and sensory receptors. The information sent to organs is transmitted through nerves.
The nerves travel to the upper and lower extremities and traverse the various joints along their paths.

3. Unfortunately, these nerves can become compressed or entrapped at various regions of the extremities, especially at "tunnel" regions, where they may be predisposed or vulnerable to compression.

4. The first operations or decompressions for different nerve entrapments were performed more than a century ago, but the disorders were described even earlier by such pioneering physicians as Sir Astley Cooper (1820s) and Sir James Paget (1850s).

5. Entrapment neuropathies are a group of disorders of the peripheral nerves that are characterized by pain and/or loss of function (motor and/or sensory) of the nerves as a result of chronic compression.

6. 10-20% of the practice’s cases
Carpal tunnel syndrome (CTS), compression of the median nerve at the wrist, is the most common entrapment neuropathy.
Cubital tunnel syndrome is the second most common and is caused by a compression at the elbow.
Other rare nerve entrapment syndromes include the suprascapular nerve, which accounts for approximately 0.4% of upper girdle pain symptoms, and meralgia paresthetica, which is a compression of the lateral femoral cutaneous nerve [LFCN] in the groin

7. Nerve entrapment syndromes result from chronic injury to a nerve as it travels through an osseoligamentous tunnel; the compression is typically between the ligamentous canal and bony surfaces.
Other potential anatomical sites for entrapment include the muscular arcade of the supinator (also known as the arcade of Frohse), the posterior interosseous nerve (PIN), and the thoracic outlet for the lower trunk of the brachial plexus.
In cases of nerve entrapment, at least one portion of the compressive surfaces is mobile. This results in either a repetitive "slapping" insult or a "rubbing/sliding" compression against sharp, tight edges, with motion at the adjacent joint that results in a chronic injury. Immobilization of the nerve with a splint or lifestyle adjustments may therefore resolve the symptoms. Entrapment neuropathies can also be caused by systemic disorders, such as rheumatoid arthritis, pregnancy, acromegaly, or hypothyroidism.

8. Repetitive injury and trauma to a nerve may result in microvascular (ischemic) changes, edema, injury to the outside layers of the nerve (myelin sheath) that aid in the transmission of the nerve’s messages, and structural alterations in membranes at the organelle levels in both the myelin sheath and the nerve axon.
Focal segmental demyelination at the area of compression is a common feature of compression syndromes.

9. Presentation Irritative or inflammation (sensory nerves) Pain
Paresthesia
Ablative symptoms
Numbness (sensory nerves)
Weakness and atrophy (motor nerves)
Chronic Cases
Dry, thin, hairless skin
Ridged, thickened, cracked nails
Recurrent skin ulcerations

10. Carpal Tunnel Syndrome
Carpal tunnel syndrome, the most common focal peripheral neuropathy, results from compression of the median nerve at the wrist.
The sulcus carpi, is covered by the flexor retinaculum, a sheath of tough connective tissue, thus forming the carpal tunnel. The flexor retinaculum is attached radially to the scaphoid tubercle and the ridge of trapezium, and on the ulna side to the pisiform and hook of hamate.

13. Affects an estimated 3 percent of adult Americans
Three times more common in women than in men
High prevalence rates have been reported in persons who perform certain repetitive wrist motions (frequent computer users)
30% hand paresthesias
10% clinical criteria for carpal tunnel syndrome
3.5% abnormal nerve conduction studies

15. Pain
Numbness
Tingling
Symptoms are usually worse at night and can awaken patients from sleep.
To relieve the symptoms, patients often “flick” their wrist as if shaking down a thermometer (flick sign).

17. Physical Examination Phalen’s maneuver Tinel’s sign
weak thumb abduction.
two-point discrimination

19. Differential Diagnostics
Tendonitis
Tenosynovitis
Diabetic neuropathy
Kienbock's disease
Compression of the Median nerve at the elbow

20. CONSERVATIVE TREATMENTS
GENERAL MEASURES
WRIST SPLINTS
ORAL MEDICATIONS
LOCAL INJECTION
****** SURGERY

21. Surgery
Should be considered in patients with symptoms that do not respond to conservative measures and in patients with severe nerve entrapment as evidenced by nerve conduction studies,thenar atrophy, or motor weakness.

24. Cubital Tunnel Sydrome
Entrapment of ulnar nerve at the elbow
Throwing athletes, weight-lifting, gymnastics, stick-handling sports
May be entrapped as passing through fibro-osseous cubital tunnel formed by medial trochlea, medial epicondylar groove, posterior UCL and arcuate ligament

26. Symptoms
Symptoms- medial elbow pain, increased with overhead activities; paresthesias in 4th-5th fingers
Positive (asymmetric) Tinel’s sign
Possible intrinsic hand weakness and atrophy
Provocative testing with elbows fully flexed and wrist extended for 3 minutes

27. Diagnosis
Plain xrays to exclude a bony compression or evidence of UCL instability
MRI may assist in a similar but more detailed fashion, but not typically necessary initially
EMG/NCS to confirm diagnosis and determine severity

28. Corticosteroid injection controversial Surgical treatment
Treat the underlying etiology
Relative rest, night splints to decrease full flexion, NSAIDs or oral steroids
Corticosteroid injection controversial
Surgical treatment

29. Ulnar Tunnel Sydrome (Guyon Canal)
Compression of ulnar nerve at Guyon’s canal
Typically in cycling
Seen also in hook of hamate and pisiform fx
Symptoms may be motor or sensory
Similar symptoms and exam to cubital tunnel

30. Treatment
Proper bicycle fitting, handlebar adjustments, frequent change in hand position, handle bar and glove padding
Wrist splints
Surgical decompression from failed non-op mgmt., especially with structural lesions such as hook of hamate fracture

31. Meralgia Paresthetica

32. Meralgia paresthetica is a condition characterized by tingling, numbness and burning pain in your outer thigh. The cause of meralgia paresthetica is compression of the lateral femoral cutaneeous nerve that supplies sensation to the skin surface of your thigh.
Tight clothing, obesity or weight gain, and pregnancy are common causes of meralgia paresthetica. However, meralgia paresthetica can also be due to local trauma or a disease, such as diabetes.
In most cases, meralgia paresthetica can be relieved with conservative measures, such as wearing looser clothing. In severe cases, treatment may include medications to relieve discomfort or, rarely, surgery.

33. Symptoms
Tingling and numbness in the outer (lateral) part of your thigh
Burning pain in or on the surface of the outer part of your thigh

34. Superficial Peroneal Nerve Neuropathy
Uncommon cause of anterolateral leg pain
Entrapment as nerve exits from deep fascia, usually 8-10 cm above lateral malleolus over anterolateral leg
Etiologies- trauma, inversion ankle injuries, muscle herniation through fascial defect, post-op complication of fasciotomy for anterior CECS, etc.

35. Symptoms- anterolateral leg pain, dorsal foot pain and paresthesias
Signs- pain/symptoms with palpation 8-10 cm above lat. malleolus over the nerve during active dorsiflexion; passive plantar flexion and inversion of ankle with or without nerve palpation
Diagnostic injection above lateral malleolus can be helpful

36. MRI may confirm entrapment
Compartmental pressure measurements to rule out CECS
NCS/EMG usually not helpful
Surgical decompression typically the most effective treatment, but success rate highly variable and many have persistent symptoms

37. Tarsal Tunnel Syndrome
Entrapment of posterior tibial nerve or its branches in the medial ankle or foot
Branches include medial and lateral plantar nerves and the medial calcaneal nerve
Etiologies- tumors, lipomas, ganglion cysts, trauma, fractures, edema, scar, valgus misalignment, poorly fitting footwear

38. Symptoms- burning/aching heel, medial ankle and arch; often worse nocturnally; worse weight-bearing; paresthesias on plantar aspect of foot
Signs- Tinel’s over the tunnel, typical symptoms with heel eversion; standing on tiptoes may produce pain

39. Plain xrays may reveal a structural lesion (healing fracture, spurs, etc.)
MRI more helpful to identify structural lesions potentially causing compression
NCS/EMG may be helpful, but often non-diagnostic

40. Treatment Rest, NSAIDs, corticosteroid injection
Footwear adjustments, including a medial arch support
Surgical release ~75% success rate