AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Neoplastic lumbosacral plexopathy (NLP) is an infrequent complication associated with advanced systemic cancer due to local or regional progression of the primary tumor. NLP is characterized by significant pain and sensorimotor deficits.

Anatomically, lumbosacral plexus consists of lumbar (L1-L4) and sacral (L5-S5) portions, which are connected by the lumbosacral trunk (L4-L5).The L1-L4 nerve roots transverse through psoas muscle and then coalesce into lumbar plexus, which then divides into anterior and posterior divisions. The first 3 nerves (iliohypogastric, ilioinguinal, femoral) of the 7 major branches of lumbar plexus provide motor and sensory innervation to the abdominal wall. The next 3 nerves (lateral femoral cutaneous, femoral, obturator) innervate the anteromedial thigh. The femoral nerve terminates into the saphenous nerve providing sensation along the medial aspect of the leg.

The sacral plexus also divides into anterior and posterior divisions, which further divide into various peripheral nerves that provide sensory motor innervation to posterior hip girdle, thigh, and anterior and posterior leg. The 5 main nerves are superior gluteal, inferior gluteal, posterior femoral cutaneous, sciatic, and pudendal nerves. The sciatic nerve divides into the common peroneal and tibial nerves in the thigh.

NLP associated with pelvic, abdominal, and retroperitoneal tumors often results in significant pain, sensory disturbance, weakness, and disability. Plexus involvement occurs as a result of tumor extension or invasion and heralds a progressive disease course. Plexopathy is part of the initial presentation of cancer in 15% of patients.

Pathophysiology

Lumbosacral plexus involvement occurs most commonly due to intra-abdominal tumor extension (73% of cases), and less commonly with growth from metastases, lymph nodes, or bone structures. A tumor can invade the plexus directly or track along the connective tissue or epineurium of nerve trunks.

The most prevalent types of tumors are colorectal tumors (20%), sarcomas (16%), breast tumors (11%), lymphoma (9%), and cervical tumors (9%). Other tumors, including multiple myeloma, account for another 37% of cases. The most common distant metastatic lesions are caused by breast cancer. In one study, the lumbosacral plexus was involved in 50 of 2261 cases of cervical cancer; however, it was involved in 38 of the 74 patients (51%) in the subgroup with proven retroperitoneal metastatic disease.

The lower plexus is involved most frequently (50%), followed by upper plexus involvement (33%), and panplexopathy (18%). Bilateral plexopathy occurs in 25% of cases and is usually caused by breast cancer metastases. The lower (sacral) plexus involvement occurs generally with colorectal and cervical neoplasms. Involvement of the sacral sympathetic nerves is less common (10%).

Malignant psoas syndrome (MPS) was first described in 1990 by Stevens and refers to severe and difficult pain due to proximal lumbosacral plexopathy, painful fixed flexion of the ipsilateral hip, and radiological or pathological evidence of malignant involvement of ipsilateral psoas major muscle.

Frequency

United States

The incidence of NLP is 0.71%.

Mortality/Morbidity

Significant morbidity occurs due to associated pain, weakness, and sensory deficits. One study noted median survival of 5.5 months after diagnosis.

Race

No known correlation is recognized between NLP incidence and race.

Sex

One study with a small number of patients noted a male-to-female ratio of 1.3:1.

Age

In one study, age at time of presentation ranged from 19-80 years with a median age of 65.5 years.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• Patients with NLP present most frequently (93%) with symptoms of pain located in regional areas, such as the low back, buttock, hip, and thigh. Features of this pain include the following:
• • The pain may be of unilateral onset, confined to one side, in 90% of cases.
  • The pain is usually constant, dull, aching, or pressurelike, but rarely burning. Cramping may be present in a radicular pattern.
  • Pain may worsen at nighttime, and patients generally have difficulty finding any comfortable position at all.
  • Involvement of the iliopsoas muscle leads patients to rest with legs and hips in flexion.
  • Pain exacerbation may occur with prolonged ambulation or sitting.
  • Pain may also radiate down the leg from epidural involvement from the tumor.
  • Eventually, such pain manifests in all patients with NLP and is the most prominent symptom. Absence of pain should prompt consideration for other diagnoses.
  • The presence of autonomic symptoms is less frequent; one of these is the "hot and dry foot" and occurs because of involvement of the sympathetic components of the plexus. A clear difference in temperature of the affected limb may be reported.
  • When the disease process manifests first with pain, it lasts from 1 week to 13 months, with median duration of 3 months, before other neurological symptoms appear.
• Weakness and sensory loss complaints eventually develop in most patients. Sensory loss occurs in 50-75% of patients and is more severe with greater motor impairment, potentially adding significantly to degree of disability.
• 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 and occur in around 10% of NLP patients.

Physical

• The most common clinical findings include muscle weakness (86%), sensory loss (73%), reflex impairment (64%), and leg edema (47%).
• Diffuse asymmetric 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 getting up from a seated position or negotiating 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 (25%) or panplexopathy (15%).
• A positive straight leg raise test is most common with panplexopathy (83%).
• Pain exacerbation may occur with Valsalva maneuver.

Causes

Tumor invasion, either local or metastatic, can lead to lumbosacral plexopathy.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Other causes for lumbosacral radiculopathy
Primary plexus tumors
Leptomeningeal disease
Epidural cord compression
Chemotherapy toxicity associated with intra-arterial treatment
Thrombocytopenia
Aortic aneurysms
Diabetes mellitus
Diabetic amyotrophy
Obstetric procedures
Trauma
Intragluteal injections

Meningeal carcinomatosis or leptomeningeal disease also may cause low back or leg pain with subacute motor or sensory involvement; however, patients with these conditions often demonstrate mental status changes, headaches, cranial nerve palsies, and/or nuchal rigidity.

In cancer patients with thrombocytopenia, retroperitoneal bleeding can cause plexopathy accompanied by rapid onset of pain and neurologic signs that usually are fully developed in 24 hours. Other associated findings include flank, thigh, or low back ecchymoses. A retroperitoneal bleed usually involves the femoral nerve and occasionally will spread to other parts of the plexus.

Other causes of lumbosacral plexopathy to consider are idiopathic in nature, aortic aneurysms, diabetes mellitus, obstetric procedures, trauma, anticoagulation therapy, retroperitoneal hematomas, surgical intervention for mesenteric thrombosis, kidney transplantation, tuberculosis, and intragluteal injections.

Acute pain is common with aortic aneurysm and the resultant weakness typically worsens over 1-2 weeks and then stabilizes. A pulsatile rectal or abdominal mass frequently is observed.

Acute thigh pain with acute or insidious onset weakness can result from diabetic amyotrophy and can be difficult to differentiate from the pain associated with aortic aneurysm. Weakness is noted with diabetic amyotrophy more often proximally with relative sparing of distal lower extremity muscles.

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Results of lab studies depend on the type of cancer and extent of involvement. Erythrocyte sedimentation rate (ESR), CBC count, alkaline phosphatase, protein electrophoresis, prostate specific antigen (PSA), and other cancer-specific labs may be abnormal depending on the clinical situation. Uremia and hydronephrosis may be an issue with ureter obstruction, especially in patients with gynecological malignancy.
• Cerebrospinal fluid (CSF) studies may reveal elevated protein with negative cytologic findings.

Imaging Studies

• The clinical diagnosis of NLP is confirmed by magnetic resonance imaging (MRI) or computed tomography (CT) scan of the affected areas. MRI is more sensitive than CT scan, provides better detail, and is preferred.
• MRI is more accurate with soft tissues. Hydroureter or hydronephrosis are common findings at time of diagnosis. Diagnosis can be difficult if the scan does not show a mass lesion, but repeating the study in another 4-6 weeks often reveals the pathology not initially apparent. Increased T2 intensity within nerve trunks with or without enhancement have been shown with NLP.
• CT scan of the abdomen and pelvis is probably the most valuable in diagnosis and gives more information on bony structures. Tumor, bony erosion, and lymphadenopathy are seen in 78% of cases. Clinical findings and CT scan levels do not always demonstrate positive correlation.
• Positron-emission tomography (PET) scan can be helpful with detecting active malignancy in plexus region. However, the sensitivity or specificity in diagnosing tumor plexopathy is not yet clear.
• Bone scan reveals pelvic, sacral, or vertebral uptake in 60% of patients with NLP.
• Myelography can be abnormal with malignant plexopathy (in 28-45% of cases).
• Routine spine and pelvic roentgenograms reveal bone destruction in 50% of patients with NLP.

Other Tests

• Electrodiagnostic testing (electromyography [EMG], nerve conduction study [NCS]) reveals abnormalities in almost all NLP patients; typical changes include acute and chronic denervation of the lumbosacral plexus. The findings are observed more extensively than would be suspected clinically. Side-to-side comparisons are helpful.
• • Myokymic discharges are not observed.
  • In the segments involved, decreased amplitudes of the evoked motor responses with normal or borderline nerve conduction velocities are noted.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Rehabilitation Program

Physical Therapy

For physical rehabilitation, the likely progression of neurologic weakness needs to be considered. If the patient is noted to have associated weakness after acute pain has subsided, one may recommend active range of motion (AROM) exercises with advancement to low resistance exercises. Assistive devices, such as a cane, walker, or wheelchair, may be required for ambulation in those patients with weakness of the hip extensors, abductors, or quadriceps with or without loss of joint position sense. Use of an ankle-foot orthosis (AFO), and rarely a knee-ankle-foot orthosis (KAFO), may be beneficial for mobility.

Occupational Therapy

The occupational therapist should assess activities of daily living (ADL) and prescribe appropriate adaptive equipment. In particular, be aware that safety with standing transfers may be impaired in cases of more distal involvement than proximal. With more proximal involvement, sit-to-stand transfers also may be affected. Equipment may be used specifically to facilitate dressing and bathing activities involving the lower extremity.

Medical Issues/Complications

• Medical or surgical treatment of the carcinoma when possible is the first treatment of choice.
• Intra-arterial chemotherapy regionally has limited use in patients with pelvic pain and intractable pain due to plexopathy.
• The most commonly used treatment with such plexopathy involves radiation treatment. Subjective improvement has been noted in 85% of patients with regard to symptoms. Objective improvement, including neurologic improvement and reduction in measurable tumor size, has been noted in 48% of patients. However, the average response duration was only 4 months.
• Pain management is an important issue and may require an analgesic ladder approach including agents specifically for the management of neuropathic pain.
• Neuropathic pain may respond to nerve stimulation, antidepressants, and antiepileptics.
• Plexopathy-associated complications, such as contractures, deep venous thrombosis, immobility, and compressive neuropathies, should be anticipated and early treatment should be provided.
• Lymphedema in the lower extremities may be an issue and can be particularly difficult to treat. Treatment should focus on improving the swelling, thus improving pain and function. Initial intervention may include wrapping with nonelastic wrapping, elevation, appropriate retrograde massage techniques, range of motion exercises, and education. With improvement in edema, compressive garments should be considered, although these may have to be custom type.

Surgical Intervention

Patients with more severe and recalcitrant pain may respond to use of epidural catheter drug delivery and/or neurostimulatory/neuroablative surgical approaches. Cordotomies have been reported to have good outcomes in Europe. However, pain relief has been noted to be transient. Such ablative procedures carry the risk of sensory and motor deficits. The mortality rate has been significant at 5%.

Occasional relief of chronic pain has been achieved with plexus dissection and neurolysis.

Consultations

Pain is a significant issue in most patients and studies have shown that pain is often poorly controlled in these patients. A multidisciplinary approach is needed. Consider early consultation with pain service, given the patient's short life expectancy following diagnosis. These patients may benefit from opiate analgesics, continuous infusion pumps, and procedures such as local and regional blocks, sympathectomy, and rhizotomy.

Other Treatment

Nonpharmacologic measures, such as transcutaneous electrical nerve stimulation (TENS) or Anodyne, may be used for neuropathic pain.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

TCAs, such as amitriptyline (10-100 mg qhs) may be helpful at low doses. Antiepileptics, such as gabapentin (300-3600 mg/d in 3-4 divided doses) also can be tried. Opiates, especially methadone and steroids, also can be considered. Mexiletine, a class 1b antiarrhythmic, at 200 mg bid, has been used for management of significant neuropathic pain due to neoplastic plexus infiltration. Low- (0.1 g/kg/d) and higher-dose (0.2-2 g/kg/d) intravenous immunoglobulin therapy has been used with success in limited cases for idiopathic brachial and lumbosacral plexopathy. However, its effectiveness in neoplastic plexopathy is unproven. A single dose (500 mg or 1 g) of intravenous magnesium sulfate has been used with success in a small sample of patients with neuropathic pain due to neoplastic plexopathy.

Drug Category: Tricyclic antidepressants

Have central and peripheral anticholinergic effects, as well as sedative effects, and block the active reuptake of norepinephrine and serotonin.

Drug Category: Analgesics

Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties, which are beneficial for patients who experience pain.

Drug Category: Muscle relaxants

Inhibit events involved in muscle contraction.

Drug Category: Antiepileptics

Used to manage severe muscle spasms and provide sedation in neuralgia.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Prognosis

• NLP progresses much faster than radiation-related plexopathy, and the patient survival rate is limited. Median survival is 5.5 months from the time of diagnosis with a range of 1-34 months. In one study, at 1-month follow-up visit, only 15-17% of patients demonstrated improvement in pain or weakness, and 28% showed improvement in CT scan findings. Over half of the patients (59%) demonstrated gradual worsening of neurologic deficits.
• In another study, 13 patients who underwent palliative irradiation for NLP had median survival of 185 days, with a range of 47-636 days.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• If the diagnosis is not established in a timely manner and proper treatment pursued, the physician is at risk for medicolegal consequences.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• Agar M, Broadbent A, Chye R. The management of malignant psoas syndrome: case reports and literature review. J Pain Symptom Manage. Sep 2004;28(3):282-93.
• Ahmad A, Barrington S, Maisey M, Rubens RD. Use of positron emission tomography in evaluation of brachial plexopathy in breast cancer patients. Br J Cancer. Feb 1999;79(3-4):478-82.
• Crosby V, Wilcock A, Corcoran R. The safety and efficacy of a single dose (500 mg or 1 g) of intravenous magnesium sulfate in neuropathic pain poorly responsive to strong opioid analgesics in patients with cancer. J Pain Symptom Manage. Jan 2000;19(1):35-9. [Medline].
• Dalmau J, Graus F, Marco M. "Hot and dry foot" as initial manifestation of neoplastic lumbosacral plexopathy. Neurology. 1989;39:871-872.
• Dhillon SS, Sarac E. Lumbosacral plexopathy after dual kidney transplantation. Am J Kidney Dis. Nov 2000;36(5):1045-8. [Medline].
• Ebner I, Anderl H, Mikuz G, Frommhold H. [Plexus neuropathy: tumor infiltration or radiation damage]. Rofo. Jun 1990;152(6):662-6.
• Garcia-Manzanares MD, Forner-Cordero I, Lavara-Perona MC, et al. Bilateral lumbosacral plexopathy after mesenteric thrombosis. Spinal Cord. Jul 1999;37(7):522-5. [Medline].
• Inoue C, Hayashi A, Yoshizawa T, et al. [Effect of intravenous immunoglobulin therapy in a case of idiopathic recurrent brachial and lumbosacral plexopathy]. Rinsho Shinkeigaku. Jun 1999;39(6):661-4. [Medline].
• Jaeckle KA, Young DF, Foley KM. The natural history of lumbosacral plexopathy in cancer. Neurology. 1985;35:8-15. [Medline].
• Jaeckle KA. Neurological manifestations of neoplastic and radiation-induced plexopathies. Semin Neurol. Dec 2004;24(4):385-93.
• Pettigrew LC, Glass JP, Maor M, Zornoza J. Diagnosis and treatment of lumbosacral plexopathies in patients with cancer. J Arch Neurol. 1984;41:1282-5. [Medline].
• Russi EG, Pergolizzi S, Gaeta M, et al. Palliative-radiotherapy in lumbosacral carcinomatous neuropathy. Radiother Oncol. Feb 1993;26(2):172-3. [Medline].
• Sloan P, Basta M, Storey P, von Gunten C. Mexiletine as an adjuvant analgesic for the management of neuropathic cancer pain. Anesth Analg. Sep 1999;89(3):760-1. [Medline].
• Stoeckli TC, Mackin GA, De Groote MA. Lumbosacral plexopathy in a patient with pulmonary tuberculosis. Clin Infect Dis. Jan 2000;30(1):226-7. [Medline].
• Stubgen JP. Neuromuscular disorders in systemic malignancy and its treatment. Muscle Nerve. Jun 1995;18(6):636-48. [Medline].
• Taylor BV, Kimmel DW, Krecke KN, Cascino TL. Magnetic resonance imaging in cancer-related lumbosacral plexopathy. Mayo Clin Proc. Sep 1997;72(9):823-9. [Medline].
• Thomas JE, Cascino TL, Earle JD. Differential diagnosis between radiation and tumor plexopathy of the pelvis. Neurology. Jan 1985;35(1):1-7. [Medline].
• Wilbourn AJ. Electrodiagnosis of plexopathies. Neurol Clin. 1985;3:511-29. [Medline].
• Wouter van Es H, Engelen AM, Witkamp TD, et al. Radiation-induced brachial plexopathy: MR imaging. Skeletal Radiol. May 1997;26(5):284-8.

Article Last Updated: Feb 7, 2007