Frankel Grade

The first widely accepted classification scheme to assess neurological function following SCI was not described until 1967 when Frankel published his classic work [2]. Frankel applied his simple and convenient 5-point scale to patients undergoing postural reduction treated at the National Spinal Injuries Center at the Stoke Mandeville Hospital. Patients were classified “arbitrarily” as Complete (A), Sensory only (B), Motor Useless (C), Motor Useful (D), or Recovery (E). This work has had considerable influence and its general framework lives on in more modern classification schemes. Although insensitive, it provided a n easy scheme for classifying patients based on obvious and easily assessed aspects of neurological function. A major short-coming of this scale, however, is the subjectivity inherent in judging what constitutes “useful”. This scale also fails to recognize laterality and the independence with which motor and sensory function can be lost. Furthermore, scores of C and D have a ceiling effect, or discontinuity, whereby disproportionately few patients improve beyond these scores [3]. This scale does, however, seem remarkably forward-thinking when today’s emphasis on the functional significance is considered.

Lucas Neuro Trauma Motor Index

The next influential scale came in 1979 from Lucas and Ducker [1]. Their system was based on both the bony level of injury and corresponding motor function. Their scale was unique in that it subdivided SCI into two types of complete lesions (neurology consistent with the bony level or caudal to it) and three types of partial lesions. Their emphasis on statistical analysis (using their motor index initial, motor index current, and recovery rate) is to be commended, however their scheme was not widely used largely because it ignores sensory function.

Tator Sunnybrook Scale

The Sunnybrook Scale, devised by Charles Tator [3] in 1982, was the next major attempt to classify neurological function following SCI. Born out of a desire to produce “a more comprehensive assessment of recovery factors”, it was essentially a modification of the Frankel scale, which subdivided C and D scores. It was thus a more sensitive ten point scale that facilitated more independent scoring of motor and sensory deficits. It also emphasized that the level of injury should be defined as the most dist a l level of intact neurological function as opposed to the most proximal damaged level, or the bony level of injury; this convention persists to this day.

American Spinal Injury Association Score

The 1980’s saw a giant leap forward for this field. The first NASCIS trial [4] and the American Spinal Injury Association (ASIA) grading system [5] ushered in a new era of precision, complexity, and rigor in neurological assessment. The scoring system used in the first NASCIS trial, published in 1984, was developed during a 2-year feasibility study. They utilized approved examiners and assessed motor function, pinprick, and light touch, producing both an expanded score and a simpler five-point scale. The motor assessment applied the Royal Medical Research Council (MRC) of Great Britain Grading Scale to 14 muscle groups chosen for functional importance, representation of spinal cord segments, and ease of examination. The sensory testing was conducted from C2 to S5, and graded as normal, decreased, or absent.

The ASIA scale is similar, and has become the most widely accepted and used scale. This scale, first published in 1982 [5] has become an international standard endorsed by the International Medical Society of Paraplegia (IMSOP). Furthermore, it has undergone numerous revisions over the years [6] and is alternatively known as the International Standard for Neurological Classification of Spinal Cord Injury. The ASIA/IMSOP scale (referred to here as the ASIA scale for brevity) tests five key muscles in each extremity, each scored out of five, thus totaling 100. It also allows for optional testing of the diaphragm, deltoids, abdominals, medial hamstrings, and hip adductors. Here sensory testing is also completed for pin prick and light touch and graded in the same fashion as the NASCIS I trial, allowing the generation of scores for each out of 112. Position sense and awareness of deep pressure/pain are also included as optional. Also similar to the NASCIS I scale, ASIA scores can be presented in simplified form via the ASIA Impairment Scale, or AIS. The AIS is essentially a modernization of the Frankel scale and bears the same form. Here A remains a complete injury and E remains normal neurological function. Intervening scores have been made more objective, with muscle power grade of 3 used to discriminate between them, but despite increased objectivity a ceiling effect continues to plague C and D scores [3].

Modified Benzel Classification System

While these “modern” scales have been a tremendous advance, they are far from perfect. Indeed, they are markedly more sensitive than their predecessors, allowing for independent motor and sensory scoring as well as delineation of sidedness. Their simplified forms allow for simplified grading, facile communication, and easy comparison to older scales. They have some drawbacks, however. Their complexity makes them time-consuming and mandate performance by specially trained personnel. As well, many aspects of spinal cord physiology remain neglected such as bowel and bladder function.

The Modified Benzel Classification system [7, 8] is a scale which attempted to address some of these deficits. It is the most recently proposed classification system and it was used in the GM-1 ganglioside trial [9]. This scale has seven grades owing to a sub-division of ASIA D into three different grades. Furthermore, this scale additionally assesses walking and sphincter function. Though a step in the right direction, this grading system has not been fully validated and cannot be applied immediately following injury when a patient is unable to ambulate [3].

Functional outcomes measures

Recent years have seen a shift across the medical literature, placing a new emphasis on quality of life measures, recognizing it as perhaps the most important health outcome. Though Ben zel’s effort is a n exception, quality of life scales have largely been used in parallel with the neurological scales to this point. The Functional Independence Measure (FIM) has been perhaps most widely used in the SCI literature. It was developed from the Uniform National Data System for Medical Rehabilitation [10] and its scoring system evaluates areas of self-care, sphincter control, mobility, locomotion, and communication. Grossly classifications are made as independent or dependent, and it was largely designed to determine burden of care. Designed for widespread application to all rehabilitation patients, many felt the need to design a scale more relevant to those with SCI. In response, Catz et al published the Spinal Cord Independence Measure (SCIM) in 2001 [11]. The SCIM covers three areas of function: self-care (score range 0 ± 20), respiration and sphincter management (0 ± 40), and mobility (0 ± 40) and has indeed demonstrated more sensitivity to functional changes in SCI patients than the FIM. It has subsequently been revised to increase interobserver reproducibility with respect to bathing, dressing, bowel management, and mobility in bed [12].

Also emerging are scales that assess walking following SCI. The Walking Index for Spinal Cord Injury (WISCI), published in 2000 [13] and more recently in revised Form [14], represents an international effort to produce a complex, valid, and Spine Classifications and Severity Measures reliable tool for assessing walking independent of burden of care. Other walking tests include the Timed Up and Go (TUG), the 10 Meter Walk test, and the 6 Minute Walk Test, all three of which were recently compared on the same cohort of patients and all were found to be valid and reliable [15].

SCALE DESCRIPTION

Injury severity based on the following scale:

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  A—Complete—No motor or sensory function is preserved in the sacral segments S4–S5

  
  
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  B—Incomplete—Sensory but no motor function is preserved below the neurological level and includes the sacral segments S4 and S5

  
  
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  C—Incomplete—Motor function is preserved below the neurological level and muscle grade less than 3

  
  
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  D—Incomplete—Motor function is preserved below the neurological level and muscle grade of 3 or more

  
  
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  E—Normal—Motor and sensory function are normal

Interpretation:

Grades are presented in ascending order of severity.

References: