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Radiation-Induced Lumbosacral Plexopathy Clinical Presentation

  • Author: Rajesh R Yadav, MD; Chief Editor: Robert H Meier, III, MD  more...
Updated: Aug 02, 2015


With prior radiation treatment and initial symptoms, a recurrent tumor may need to be distinguished from postradiation plexopathy. The median symptom-free interval for radiation-induced lumbosacral plexopathy, from treatment to the initial neurologic symptom, is 5 years, with a range of 1-31 years.[4]

  • Patients with radiation-induced lumbosacral plexopathy most commonly present with painless weakness in 1 or both legs. Pain is present initially in only 10% of patients, although ultimately it is noted in as many as 50% of patients. The incidence of initial pain is lower than that of brachial plexopathy. This pain is described in varying terms, such as aching, burning, pulling, cramping, and lancinating; however, pain rarely is a major problem.
  • Weakness is asymmetrical. At the height of illness, the ratio of bilateral to unilateral illness is 5:1. Acute lower extremity paralysis has been noted in a patient with cervical cancer 10 weeks after completion of radiation treatment.[6]
  • Sensory loss occurs in 50-75% of patients and is more severe with greater motor impairment, which can add significantly to disability.
  • Bladder or bowel incontinence may occur.[7]


See the list below:

  • In radiation-induced lumbosacral plexopathy, motor deficits in the lower extremities commonly are bilateral (80%) and asymmetrical. Diffuse limb weakness with distal predominance in L5-S1 distribution is relatively common (55% of patients). Exclusive proximal paresis in the distribution of L2-L4 is less common (10% of patients), as is femoral neuropathy (5% of patients). Moderate weakness is present in 50% of patients, with equal distribution of mild and severe weakness.
  • Deep tendon reflexes (DTRs) almost always are abnormal at the knees and/or ankles and usually are present bilaterally.
  • Sensory impairments are present in most patients (75%) and more often are bilateral. No specific sensory modality is favored. The distal lower extremities are affected more commonly than are the proximal lower extremities. Impaired deep sensation occurs with severe, superficial sensory loss.
  • Skin changes may be present in areas of radiation portals.


Radiation dosage, treatment technique, and concomitant use of chemotherapy are associated with development of radiation-induced lumbosacral plexopathy.

Contributor Information and Disclosures

Rajesh R Yadav, MD Associate Professor, Section of Physical Medicine and Rehabilitation, MD Anderson Cancer Center, University of Texas Medical School at Houston

Rajesh R Yadav, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Michael T Andary, MD, MS Professor, Residency Program Director, Department of Physical Medicine and Rehabilitation, Michigan State University College of Osteopathic Medicine

Michael T Andary, MD, MS is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Medical Association, Association of Academic Physiatrists

Disclosure: Received honoraria from Allergan for speaking and teaching.

Chief Editor

Robert H Meier, III, MD Director, Amputee Services of America; Active Medical Staff, Presbyterian/St Luke’s Hospital, Spalding Rehabilitation Hospital, Select Specialty Hospital; Consulting Staff, Kindred Hospital

Robert H Meier, III, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, Association of Academic Physiatrists

Disclosure: Nothing to disclose.

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