The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) is the most widely used classification in the field of spinal cord injury medicine. Since its first publication in 1982, multiple revisions refining the recommended examination, scaling, and classification have taken place to improve communication, consistency, and clarity. This article describes a brief historical perspective on the development and changes over the years leading to the current ISNCSCI, detailing the most recent updates of 2011 and the worksheet 2013 as well as issues facing the ISNCSCI for the future.

Keywords

Spinal cord injury

International Standards

Classification

Neurologic level

Key points

Historical background and revisions

Accurate communication between clinicians and researchers working with SCI patients requires that standards be used in the classification of neurologic impairment.1 Such a standardized method is important to help document the course of recovery and the effect of interventions in the treatment of SCI, including regeneration.2 To this end, the American Spinal Injury Association (ASIA) first developed and published the Standards For Neurological Classification Of Spinal Injury Patients in 1982,1 which has since become the most widely used classification in the field.

Prior to this, in an attempt for consistency of definitions in 1969, a questionnaire was completed by leading physicians in the field of SCI to establish international agreement on neurologic terminology for SCI and to compare their opinions on the best time to accurately predict outcome after SCI. Their recommendations were published, but there was no agreement on the overall classification of SCI.3 Several classifications for SCI were subsequently proposed based on bony patterns of injury, mechanism of injury, neurologic function, and functional outcome.4–10 In 1969, Frankel and colleagues11 described a 5-grade system of classifying traumatic SCI, with a division into complete (A) and 4 incomplete (B–E) injury grades. The purpose of this article was to describe results of postural reduction in the treatment of SCI, and they described their classification as “crude.” ASIA’s first booklet of the Standards For Neurological Classification Of Spinal Injury Patients,1 published in 1982, incorporated the Frankel grades A–E along with an introduction of motor testing of key muscle groups and sensory testing in 29 dermatomes. These standards defined or described the following:

The standards from 1982 were refined by ASIA over the next 10 years, involving input from SCI clinicians and researchers.12–15 Changes included the use of specific key areas with anatomic landmarks to define the sensory level, combining the S4 and S5 dermatomes into a single S4-5 dermatome (perianal area), reducing the total number of dermatomes to 28, and redefining the zone of injury as the zone of partial preservation (ZPP) of sensory and/or motor function. Other changes included having only the elbow flexors examined to test the C5 myotome, clarification of muscle grading in the determination of motor levels, and clarification of the Frankel classification in terms of the degree of incompleteness (Frankel grade C vs D) as recommended by Tator and colleagues.13 Use of the terms, quadraparesis and paraparesis, was discouraged because they imprecisely described incomplete lesions.

In 1992, the fourth revision of the ISNCSCI was published.16 The key change of this major revision was the replacement of the Frankel classification with the ASIA Impairment Scale (AIS), with a major change in adopting the sacral sparing definition to determine the completeness of the injury. The sacral sparing definition of the completeness of the injury was considered a more stable definition, because fewer patients convert from incomplete to complete status over time postinjury.17 The AIS, similar to the Frankel scale, described 5 different severities of SCI. Other features of the 1992 revision included

These standards were endorsed by the International Medical Society of Paraplegia and, thereafter, became known as the “International Standards for Neurological and Functional Classification of Spinal Cord Injury.”16

In 1994, ASIA published a written manual for the ISNCSCI and videos of the examination.18 To the 1996 version of the ISNCSCI booklet included clarification of how to score muscles whose strength may be affected by inhibiting factors and further clarification of how to differentiate between AIS C and D plus instructions on how to determine the motor level when the sensory level falls into a region where the key muscles cannot be clinically tested; for C1-C4, T2-L1, and S3-5, the motor level is designated as the same as the most rostral normal sensory level.19

The revisions to the ISNCSCI in 200020 further clarified motor incomplete injuries and how to document the ZPP and eliminated the FIM from the standards. This revision developed the now current title, The International Standards for the Neurological Classification of Spinal Cord Injury. In 2003, ASIA published a revised version of the written manual for the ISNCSCI.21 Additional minor revisions and reprintings of the booklet were published in 2002, 2006, and 2008. In 2006, ASIA started developing an Internet-based learning course for the ISNCSCI, called the International Standards Training eLearning Program (InSTeP) that is available and continues to be updated along with the ISNCSCI. InSTeP offers modules on anatomy as well as how to perform an examination and classify an injury based on the AIS.22 In 2009 an update was published to explain some of the updates and processes of the International Standards Committee.23

2011 revisions of the ISNCSCI

In 2011, the seventh revision of the ISNCSCI was published,24 along with an accompanying explanatory article,25 and included some clarifications as well as changes that were substantial enough such that the 2003 reference manual was no longer to be used or distributed.

The clarifications of the 2011 revisions included