History
Patients with neoplastic lumbosacral plexopathy (NLP) present most frequently (93%) with pain located in regional areas, such as the low back, buttock, hip, and thigh. Features of this pain include the following:
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The pain may be of unilateral onset, being confined to one side, in 90% of cases.
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The pain is usually constant, dull, aching, or pressurelike, but it is rarely burning. Cramping may be present in a radicular pattern.
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The pain may worsen at night, and patients generally have difficulty finding a comfortable position.
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Involvement of the iliopsoas muscle leads patients to rest with their legs and hips in flexion.
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Pain exacerbation may occur with prolonged ambulation or sitting.
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The pain may also radiate down the leg as a result of epidural involvement from the tumor.
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Eventually, such pain manifests in all patients with NLP and is the most prominent symptom. An absence of pain should prompt consideration of other diagnoses.
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The presence of autonomic symptoms is less frequent; one of these, the "hot and dry foot," occurs because of the involvement of the sympathetic components of the plexus. [14] A clear difference in temperature of the affected limb may be reported.
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When the disease process manifests first with pain, it lasts from 1 week to 13 months, with a median duration of 3 months, before other neurologic symptoms appear.
Weakness and sensory loss complaints eventually develop in most patients. [12] Sensory loss occurs in 50-75% of patients and is more severe with greater motor impairment, potentially adding significantly to the degree of disability for the patient.
Muscle weakness occurs in most patients and is progressive and diffuse. Unilateral weakness and gait abnormalities are common.
Incontinence and impotence generally imply bilateral plexus involvement; they occur in about 10% of NLP patients.
In a retrospective study of nine patients with NLP resulting from the perineural spread of tumors from pelvic malignancies, Lee et al found that six patients developed pain in the perianal or inguinal area prior to pain in the extremities. Five patients experienced neurogenic bladder or bowel symptoms. [15]
Physical
The most common clinical findings in neoplastic lumbosacral plexopathy include muscle weakness (86%), sensory loss (73%), reflex impairment (64%), and leg edema (47%).
Diffuse, asymmetrical motor deficits involving more than 1 nerve root develop; associated gait abnormalities are noted.
With lumbar plexus involvement, weakness usually occurs in the thigh muscles, producing weakness when the patient rises from a seated position or negotiates steps.
Involvement of the lumbosacral trunk is associated with a foot drop and numbness of the dorsum of the foot.
In patients with sacral involvement, weakness of foot flexion and hamstrings occurs.
Sensory deficits are almost exclusively unilateral and can range from mild to severe. The location of sensory deficits in specific dermatomes offers clues to the nerve root or specific nerve involvement.
Patellar tendon reflex may be impaired with upper plexopathy, and ankle reflex impairment may be noted with lower plexopathy.
Peripheral edema is seen more commonly with panplexopathy (80%) than with upper (41%) or lower plexopathy (37%).
Rectal mass is found more often with lower plexopathy (43%) than with upper plexopathy (25%) or panplexopathy (15%).
A positive straight leg raise test is most common with panplexopathy (83%).
Pain exacerbation may occur with the Valsalva maneuver.
Causes
Tumor invasion, either local or metastatic, can lead to lumbosacral plexopathy.
