Back

New Classification System Takes the Guesswork Out of Treatment Planning For Neck Injuries

There's a move on now in the medical community to find reliable, valid ways to classify a problem and then decide how to treat it. In this study, orthopedic surgeons from St. Louis University School of Medicine check out the Cervical Spine Injury Severity Score (CSISS) for its user friendliness and accuracy. The CSISS is for patients with neck injuries involving the lower cervical spine (C3 to C7). This is an area of common injury. Predicting who might need surgery to stabilize the neck is the main goal of the CSISS approach.

Other classification models for the lower cervical spine focus on how the injury occurred (called the mechanism of injury). But the CSISS uses X-rays and CT scans to take a look at four anatomical features of the cervical spine and score them based on injury present (e.g., fracture, dislocation).

The scoring system takes into account the location of the injury, severity (nondisplaced vs. displaced fracture), and neurologic damage. Four columns of the cervical spine are evaluated separately: the two facet (spinal) joints, the vertebral body, and the posterior area of the spinous process. You can feel the spinous processes of your spine by rubbing your fingers up and down the back of your neck. The largest bump near the top of your spine is the spinous process of C2. At the base of the neck where the cervical and thoracic spines join together, you'll feel another large spinous process. That's C7.

These bony knobs are the place where the two lamina bones join together at the back of the spine. There is a bony ring that attaches to the back of the vertebral body. The ring forms an opening for the spinal cord to travel from the brain down to the end of the spine. This ring has two parts. Two pedicle bones form a short column of bone that connects directly to the back of the vertebral body. Two lamina bones join the pedicles to complete the outer rim of the ring.

The authors provide a CT scan photograph to show the reader where the four columns are (right and left facet joints, vertebral body, posterior ring with spinous process) and how the fractures are scored (from zero to five). Each column is scored independently and then the scores are added up for all four columns. Zero indicates no fracture or dislocation is present. A score of one is given for a mild (one to three millimeter) nondisplaced fracture. A score of two means there is a one to three millimeter displaced fracture. Three is for a three to five millimeter displacement. And anything more than five millimeters is scored as a five.

The scores reflect not only the amount of displacement (the higher the score, the more severe the injury), but also give the surgeon an idea of how stable/unstable the fracture site is. A CSISS score of seven or more is a sure sign that surgery is needed to stabilize the spine. In research terms, a score of seven has a specificity of 100 per cent and a sensitivity of 73 per cent. Specificity shows the ability of a test to determine a true negative for the condition (i.e., the spine is not fractured). Sensitivity reflects the ability of the test to show a true positive (i.e., the spine is fractured/unstable).

In the study, 15 physicians (junior residents, senior residents, attending spine surgeons) looked at the X-rays and CT scans of 50 patients with known lower cervical spine injuries from trauma. All physicians had specialized training in the treatment of traumatic spinal injuries. Without any specific instructions, they used the CSISS scoring system on each of the 50 cases. A month later, they attended an instructional lecture on how to use the CSISS scoring system. A month after the lecture, the same 15 surgeons reassessed the same 50 patients using the CSISS. The results were compared from before to after the instructional lecture to show whether or not this system can be taught easily. And the results were compared to the actual patient cases. This is a measure of how accurate, valid, and reliable the CSISS classification system is.

The authors report that the CSISS is both reliable and teachable. Physicians with a wide range of orthopedic training can use it. Scores were definitely better after the instructional workshop. So before using the CSISS classification system, it is advised that some training should be provided. The scoring system is easy to use and may become the universally accepted classification system needed to assess lower cervical spine injuries.

The unpredictable nature of these types of injuries and the difficulty of seeing ligament injury with imaging studies makes treatment planning difficult. Having a classification system like the CSISS to analyze the fracture type and plan treatment would be very helpful for trauma orthopedic surgeons. It would also make communication easier between and among spinal surgeons and trauma specialists if everyone were using the same assessment tool to talk about the injury.

The authors conclude by saying that their study provided an independent look at the CSISS, since they were not part of the group who did the original research and design of this tool. The CSISS passed their scrutiny and found to have excellent reliability and reproducibility at all levels of experience and training. Now, other groups need to do the same thing to verify these findings before the CSISS can be adopted universally by all. Using an instructional lecture to improve scoring is advised.

References: Scott W. Zehnder, MD, et al. Teachability and Reliability of a New Classification System for Lower Cervical Spinal Injuries. In Spine. September 1, 2009. Vol. 34. No. 19. Pp. 2039-2043.

Back