Neoplastic Lumbosacral Plexopathy

Updated: Jul 12, 2017
  • Author: Rajesh R Yadav, MD; Chief Editor: Robert H Meier, III, MD  more...
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Overview

Practice Essentials

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, the 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 the lumbar plexus, which then divides into anterior and posterior divisions. The first three nerves (iliohypogastric, ilioinguinal, femoral) of the seven major branches of lumbar plexus provide motor and sensory innervation to the abdominal wall. The next three 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 the posterior hip girdle, thigh, and anterior and posterior leg. The five main nerves are the 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. [1] 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.

Workup

The clinical diagnosis of NLP is confirmed by magnetic resonance imaging (MRI) or computed tomography (CT) scanning of the affected areas. MRI is preferred because it is more sensitive and provides better detail than CT scanning. [2]

Electrodiagnostic testing reveals abnormalities in almost all patients with neoplastic lumbosacral plexopathy. [3]

Management

Medical or surgical treatment of the carcinoma when possible is the first treatment of choice.

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 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, in rare cases, a knee-ankle-foot orthosis (KAFO) may be beneficial for mobility.

Patients with more severe and recalcitrant pain may respond to the 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%.

Related Medscape Drugs & Diseases topics:

Diabetic Lumbosacral Plexopathy

Radiation-Induced Lumbosacral Plexopathy

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Pathophysiology

Lumbosacral plexus involvement occurs most commonly due to intra-abdominal tumor extension (73% of cases); it occurs 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.

A study by Capek et al indicated that different types of pelvic neoplasms can lead to lumbosacral plexopathy via the same route, using “splanchnic nerves as conduits” and spreading “from the end organ to the lumbosacral plexus.” They added that these tumors can produce muscle and bone “metastases” by continuing their spread via osseous and muscle nerve branches. [4]

The most prevalent types of tumors are colorectal tumors (20%), sarcomas (16%), breast tumors (11%), lymphoma (9%), and cervical tumors (9%). [5] 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 (sacral) plexus is involved most frequently (approximately 50%), followed by upper plexus involvement (more than 30%) and panplexopathy (18%). [6] Bilateral plexopathy occurs in 25% of cases and is usually caused by breast cancer metastases. Lower 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 radiologic or pathologic evidence of malignant involvement of the ipsilateral psoas major muscle. [7]

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Epidemiology

Frequency

United States

The incidence of neoplastic lumbosacral plexopathy is 0.71%.

Mortality/Morbidity

Significant morbidity from neoplastic lumbosacral plexopathy occurs due to associated pain, weakness, and sensory deficits. [8] One study noted median survival of 5.5 months after diagnosis. In patients with prostate cancer, [9] symptoms may persist for years and survival may be longer.

Race

No known correlation is recognized between the incidence of neoplastic lumbosacral plexopathy and race.

Sex

One study noted a male-to-female ratio for neoplastic lumbosacral plexopathy of 1.3:1, although the investigation involved just a small number of patients.

Age

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

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