radiculopathy pearls

Differentiating C5 and C6 radiculopathies may be difficult due to common involvement of the deltoid, biceps, brachialis and brachioradialis. However, the rhomboids implicate the C5 root preferentially, and pronator teres/FCR implicate C6. Be careful because C6 radiculopathies can also mimic C7 radiculopathies with abnormalities in triceps, anconeous, pronator teres and FCR. C7 radiculopathy-- changes are found in triceps, anconeous, FCR, and occassionally pronator teres. The latter two are important because they are median innervated and the diagnosis is not being based on radial muscles only. Extensor indicis proprius, which is C8 is spared here. C8 radiculopathy-- can see changes in radial mm (ext proprius and EPB); median nerve muscles (FPL and +/- APB) plus all the ulnar muscles. The APB is often spared. L2-4 radiculopathies-- abnormalities are often (but not always found in thigh adductors, quadriceps muscles and iliacus. L5 radiculopathy-- affects tibialis anterior, extensor hallucis, peroneus longus and EDB (all of common peroneal) plus FDL, tibialis posterior, TFL, gluteus medius and maximus. Study tensor fascia lata which is sensitive to L5 radiculopathy but is one of two such muscles that do no emanate from the sciatic nerve (the other is the gluteus medius). S1 radiulopathy-- the affected muscles are often the abductor hallucis, ADQ, soleus, gastrocnemius, and the glutei esp maximus, and short head of biceps

Femoral/saphenous neuropathy

Signs and symptoms-- weakness and atrophy of the quadriceps muscle, reduced knee reflex, sensory disturbance over the anterior thigh/medial calf.

PEARLS

1) HIP FLEXOR MUSCLES MUST BE TESTED AND IF THEY ARE INVOLVED IT SIGNIFIES INVOLVEMENT OF LUMBAR PLEXUS.

2) ELDERLY PATIENTS MAY STATE THAT THEIR LEG COLLAPSED OR THAT THEY CANNOT ELEVATE THE LEG SUFFICIENTLY TO CLIMB STAIRS WITHOUT RECOGNIZING THE WEAKNESS OF THE MUSCLE AFFECTED.

Etiologies are many. Biemonds studied 50 patients. Four had retroperitoneal tumors, one retroperitoneal hematoma (often due to bleeding diathesis, six had lacerations or trauma, six had femoral neuropathy from diabetes, fifteen had radiculopathy masquerading as femoral neuropathy, eighteen were unknown included elderly and postulate was that they were diabetic or vascular). Iatrogenic causes include trauma after attempted femoral arterial puncture or catheterisation, intrapelvic operations with bleeding ( including renal transplant) or stretch due to marked extension or flexion of the hip. This can occur with coma after intoxication, or during childbirth, especially with poorly padded stirrups used in patients already numb from an epidural injection.

EMG PEARLS
1) Femoral nerve slowing can be further evaluated by saphenous nerve conductions (if abnormal its not radiculopathy). Plexus lesions have normal femoral motor nerves, abnormal saphenous nerve conductions, and EMG abnormalities outside femoral nerve territory (check....) L4 radiculopathy shows EMG abnormality ooutside L4 myotome including paraspinal muscles (check...) Saphenous nerve involvement (one of three branches of the femoral nerve) produces abnormal sensation on medial calf. May get Tinel's sign along nerve anywhere from Hunter's canal above knee. Can occur from procedures in Hunter's canal or at knee. EMG of femoral neuropathy: often more useful than NCS. Examine lumbar paraspinals and obturator innervated muscles. EMG femoral innervated muscles: VM, RF, iliopsoas; obturator (adductor longus); superior gluteal nerve (TFL), and lumbar paraspinal muscles. ADD-- 4 fb distal to pubic tubercle , adducts limb.

Ilioinguinal neuropathy

Clinical-- burning pain in abdomen into inner/upper thigh or into scrotum or labia majora. There may be tenderness slightly medial to anterior iliac spine or a Tinel's sign over the lower abdomen. PEARL if complete palsy is present lower abdomen may bulge mimicking a primary hernia. Patients may walk bent over or have trouble rising from a chair. They may walk flexed forward "like a novice skier." Etiology may be traumatic; blow to abdomen, surgery such as appendectomy or more commonly herniorrhaphy (may have occurred previous suggesting etiology is fibrosis or scar formation around the nerve). Differential includes entrapment of neighboring homologous iliohypogastric nerve, also of T12-L1, or genitofemoral nerve which courses retroperitoneally and can be caused by hematoma or tumor. Diagnosis: with nerve blocks. Treatment: surgical resection helped more than 75 %. The nerve arises from L1 and L2 roots, supplies skin over the upper/medial thigh, the root of the penis, the upper scrotum or labia majora, and also innervates the transversalis and interior oblique muscles. It follows the pattern of an intercostal nerve, winding around the inner trunk to the medial anterior iliac spine.

Traumatic neuropathy: stingers

Elman L, McCluskey L. Occupational and Sport Related traumatic neuropathy. The Neurologist 2004; 10:82-96 The burner or stinger is the most common sports related peripheral nerve injury and is caused by injury either to the C5-6 root or the superior trunk of the brachial plexus. Multiple postulates of causes though the most commonly proposed is downward displacement of the shoulder from the neck during tackling in a shoulder down position. The Torg ratio is a measure of spinal stenosis determined by cervical spine x rays does not predict stingers but does predict recurrence. Accordingly high school and college players usually have as the cause stretch of the brachial plexus whereas professionals with recurrent stingers have spinal stenosis. Acute disc herniation is not a cause however. Symptoms are immediate pain, numbness and paresthesias that last minutes. Weakness if it occurs may persist. Neck pain is not common. If sensory symptoms predominate its usually due to compression of the DRG within the neural foramen. Exam of the neck shoulder and C spine looking for point tenderness or fracture is done. Any neurologic deficit requires abstention from play. Muscle weakness at 72 hours predicts an abnormal EMG. On EMG, spontaneous activity in the paraspinals helps to localize to the nerve root, and sensory findings with a normal SNAP amplitude suggest localization in the forament with compression of the DRG. Decreased SNAP amplitude suggests a brachial plexus localization. Return to play is not determined by normalization of EMG. Persisting pain, restricted ROM, or neurologic deficit requires PT prior to return to play, for strengthening of weakened muscles as well as stabilization of brachial plexus and restoration of the normal cervical lordosis. Education of tackling technique and use of proper equipment is part of rehabilitation.

Traumatic neuropathy suprascapular nerve

Activities at risk are ones with overhead activity such as volleyball, baseball, weight lifting, wrestling, dancing and assembly line work. Its also caused by trauma (stab wounds above scapula), improper use of crutches, and rupture of the rotator cuff. Clinical presentation involves posterolateral shoulder pain, weakness of initiating abduction and external rotation of the shoulder, and muscle atrophy. Weakness of infrapinatus causes weakness in externally rotating arm at shoulder. The crossed adduction test is a provocative test that is positive when pain is produced through passive adduction of the extended arm across the chest. Sensory deficit can occur in the upper arm due to sensory branches. Evaluation is imaging of cervical spine and shoulder (films and/or MRI), EMG, or diagnostic nerve block of suprascapular nerve to verify the diagnosis. Conservative treatment is rest followed by PT; surgery is indicated if full recovery is not achieved within six months. Over-use and traction injuries responded equally to surgical/conservative therapy whereas ganglion cysts and compression neuropathies are best treated surgically. Anatomically the nerve passes through the supracapsular notch and the spinoglenoid notch. At the suprascapular notch the mechanism proposed is abnormal contact between the suprascapular nerve and the transverse ligament during shoulder abduction or adduction across the chest. Isolated painless weakness of the infraspinatus muscle occurs at the spinoglenoid notch; this occurs in volleyball players.

Long thoracic neuropathy and dorsal scapular

Occurs in many sports, but especially tennis. Its due to acute and/or repetitive use when the arm is raised and head is turned in the other direction. It can be due to compression of C5-6 roots as they travel through the scalene muscles, bow-stringing of the nerve across a fascial band, or traction injury. Non traumatic causes include brachial neuritis (idiopathic, postviral, or post surgical). Other causes are stab wounds, direct pressure from a heavy shoulder bag or shoulder braces during surgery, including thoracotomy, axillary node resection, resection of the first rib for TOS, and radical mastectomy. Blows to the sholder or lateral thoracic wall during falls or injuries can cause it. Its reported as the sole presentation of lyme disease.

The serratus anterior stabilizes the scapula against the chest wall, and long thoracic neuropathy causes weakness and difficulty moving the shoulder and arm, especially abduction or flexion above shoulder level. Patients may have a dull ache around the shoulder girdle. The shoulder looks funny due to winging. Clinical signs include scapular winging with arm outstretched against the wall. The superior angle of the scapula flips medially whereas the inferior angle swings laterally (opposite of that seen in axillary neuropathy). In contrast to trapezius weakness, in which winging is exaggerated with abduction of the arm, in LT neuropathy, its worse with outstretched arm thrust forward. Arm abduction beyong 110 degrees may be impossible. Acutely there may be shoulder pain but chronically it may be painless. Besides axillary neuropathy, differential includes scapular winging due to muscular dystrophy, C7 radiculopathy, and separation of serratus from insertion in a fracture of the scapula (easy to repair). See pictures of long thoraic and axillary neuropathy in Stewart, p 160 and 90 respectively.

Evaluation is x rays of shoulder, chest and shoulder to rule out a compressive lesion such as an osteochondroma. EMG is needed to confirm that the weak muscle is the serratus anterior as the trapezius also can produce scapular winging. It is formed directly from nerve roots C5-7 and will be NORMAL in plexopathy, abnormal with root lesion. EMG of serratius anterior is done with patient lying on the opposite side, arm adducted across the chest. It can be done by looking at medial scapular border , lower aspect below rhomboids. In the mid axillary line, isolate a rib, anterior to the lattissmus dorsi, posterior to the breast tissue in a woman. Treatment is rest, bracing and PT for ROM and strengthening of the shoulder girdle. Braces maintain scapula against the thorax to prevent further winging. Surgery for long thoracic palsy not due to penetrating trauma is only after 1-2 years of observation as natural history favors recovery. The current procedure of choice is transfer of the sternal head of the pectoralis major to the inferior angle of the scapula.

Morton's toe neuroma

Clnical-- burning pain over the head of the fourth metatarsal radiating into the toe. Pain is worse by standing and/or walking, better with lying or elevating the foot. Extending the toes by squatting or kneeling makes it worse. Exam may show diminished sensation on the medial half of the fourth toe. Nerve conductions may involve simultaneous recording of toes I and V with reference electrode i between. The cause is traumatic. It may be related to walking, jogging, squatting or wearing high heeled shoes. Treatment is padding the metatarsal head in shoe, or eventually surgery to remove the nerve is definitive. It is usually a white fibrous enlargement at the branch point of the nerve. Alternative procedure is release the ligament of the deep plantar fascia without excision of the neuroma.