AMA Guides® Newsletter

Articles

Cauda Equina Syndrome

Leon H. Ensalada

Pages 1–2

DOI: 10.1001/amaguidesnewsletters.2000.JanFeb01

Abstract
The cauda equina is a collection of peripheral nerves in the common dural sheath within the lumbar spinal canal. Cauda equina syndrome, also known as bilateral acute radicular syndrome, usually is caused by a large, sequestered acute disc rupture at L3-4, L4-5, or L5-S1 that produces partial or complete lesions of the cauda equina–lower motor neuron lesions associated with flaccid paralysis, atrophy, and other conditions. Patients usually present with a history of back symptoms that have worsened precipitously. The syndrome includes back pain, bilateral leg pain, saddle anesthesia, bilateral lower extremity weakness, urinary bladder retention, and lax rectal tone. Cauda equina syndrome is rated using Diagnosis-related estimates (DRE) lumbosacral categories VI or VII. Category VI, Cauda Equina–like Syndrome Without Bowel or Bladder Signs, is used when there is permanent bilateral partial loss of lower extremity function but no bowel or bladder impairment. Category VII, Cauda Equina Syndrome with Bowel or Bladder Impairment, is similar to Category VI but also includes bowel or bladder impairment. The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) uses the term cauda equina syndrome with reference to both the thoracolumbar and cervicothoracic spine regions; this usage is unique to the AMA Guides but maintains the internal consistency of the Injury Model, which is the best approach to date for assessing spine impairment.
Letter to the Editor: Assessing Mild Traumatic Brain Injury

Steven Mandel, Edward A. Maitz, John E. Gordon, David Massari, Joely Esposito, Heidi Mandel

Pages 2–3

DOI: 10.1001/amaguidesnewsletters.2000.JanFeb02

Abstract
The authors respond to an article, Assessing Mild Traumatic Brain Injury, that appeared in the November/December 1998 issue of the Guides Newsletter. The authors of the article referred to several shortcomings of neuropsychological assessment; specifically, they questioned the ecological (real-world) validity of such testing for less severely impaired individuals. The authors of the letter agree that neuropsychological testing may underestimate problems with attention, concentration, and memory that patients experience in real-world settings. The letter writers identify research that indicates a correlation between neuropsychological test findings and an individual's ability to perform in a work environment, and they emphasize the need to consider the individual's environment before determining the degree of functional impairment based on neuropsychological test findings. The letter writers also suggest that evaluators use recently developed measures of malingering in test batteries, and they dispute the existence of an “overreliance on technicians for test administration.” The authors of the original article respond that questions of ecological validity are less relevant when neuropsychologists do not generalize from test scores to real-world performance. The authors of the article mention their work in detecting malingering and report only preliminary and variable success. Finally, the authors of the original article note that limited space precluded discussion of all the issues raised by the letter's authors.
Quick Reference: Chapter 4: The Nervous System

Pages 4–4

DOI: 10.1001/amaguidesnewsletters.2000.JanFeb03

Abstract
Impairment rating for conditions that affect the spinal cord is discussed in the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, Section 4.3. Spinal cord lesions produce varied and characteristic patterns of neurologic loss, depending on the portion of the cord affected, and the AMA Guides divides them into six categories: station and gait, use of upper extremities, respiration, urinary bladder dysfunction, anorectal dysfunction, and sexual functioning. With respect to station and gait, the functional result of the disorder is rated, not the underlying pathology (infarct, contusion, or otherwise), so that different conditions with similar functional outcomes can have similar ratings. Because many activities of daily living depend on dexterous use of the dominant upper limb, loss or loss of use of that extremity usually results in greater impairment than if the contralateral limb were involved. Section 4.3c addresses breathing only in terms of neurologic limitations, and other aspects are covered in chapters that address the respiratory system; criteria for neurologic impairment of the bladder (used to rate bladder dysfunction related to neurologic pathology, based primarily on ability to control bladder emptying); impairment ratings associated with anorectal dysfunction; and rating sexual functioning.
Clinical Update: Spinal Cord Impairments

Lorne K. Direnfeld

Pages 5–6

DOI: 10.1001/amaguidesnewsletters.2000.JanFeb04

Abstract
Lower urinary tract dysfunction may result from a variety of neurologic disorders, including traumatic spinal cord injury, head injury, a cauda equina syndrome, or trauma to the peripheral lumbosacral nerves. Urinary incontinence can be divided into five categories: stress incontinence, urge incontinence, mixed incontinence, overflow incontinence, and total incontinence. A table lists each type, provides a description, and gives both common and neurological examples. Evaluation of voiding dysfunction should not be based on symptoms alone, and urodynamic evaluation is required also. Indeed, urodynamic evaluation is the only means to establish a functional interrelationship of the components of the lower urinary tract. Most ratings of neurogenic bladder dysfunction are performed using Section 4.3d, Urinary Bladder Dysfunction, and Table 17, Criteria for Neurologic Impairment of the Bladder in the AMA Guides to the Evaluation of Permanent Impairment. Ratings for whole-person permanent impairment depend on symptomatology (ie, urgency, dribbling, or incontinence), voluntary control, and bladder reflex activity. If problems with urinary system dysfunction are related to a combination of neurologic and urologic pathology, including pathology in the upper urinary tract, ratings from both sections can be combined using the Combined Values Chart.
Questions and Answers

Christopher R. Brigham, James B. Talmage

Pages 7–7, 12

DOI: 10.1001/amaguidesnewsletters.2000.JanFeb05

Abstract
Workers’ compensation in Canada is a legislated system of social insurance that is funded by assessments levied on employers. Thirteen established Workers’ Compensation Board (WCB) systems have regional jurisdiction and responsibility for administering and adjudicating compensation for the injured worker. Disability awards for certain injuries are determined by statute; others are determined using an acceptable reference or impairment schedule such as the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides). On August 22, 1960, Dr D. E. Bell presented to the Association of Workers’ Compensation Boards of Canada an impairment rating schedule to represent the loss of earning capacity and fulfill the spirit of workers’ compensation. Dr Bell's schedule has served as the basis for many Canadian WCB Primary Rating Schedules. Most jurisdictions refer to the AMA Guides in instances when the primary schedule is inadequate. A table in this article lists the current primary and secondary schedules for assessment of impairment in Canada; another table shows the differences in the ratings between Dr Bell's schedule and the AMA Guides. The AMA Guides is used principally only in Yukon and Prince Edward Island and is used for impairment estimations of more complicated injuries in all regions but Quebec.
Impairment Tutorial: Impairment From Neurogenic Bladder Dysfunction

Steven Mandel, Christopher R. Brigham

Pages 8–8, 11

DOI: 10.1001/amaguidesnewsletters.2000.JanFeb06
Legal Update: Canadian Workers’ Compensation Impairment Schedules

E. Klimek

Pages 9–9

DOI: 10.1001/amaguidesnewsletters.2000.JanFeb07
Literature Review

Pages 10–11

DOI: 10.1001/amaguidesnewsletters.2000.JanFeb08