A team of researchers from South Korea undertook a retrospective case control study to evaluate whether long spine fusion cases (3 or more levels) resulted in a measurable difference in post-op functionality when compared to short spine fusion (2 or fewer levels) cases.
Their work, “Minimum Three-year Follow-up of Specific Functional Disabilities After Multilevel Lumbar Fusion: Comparison of Long-level and Short-level Fusion,” appears in the October 15, 2019 edition of Spine.
Jin-Sung Park, M.D., the first author of the paper, explained the reasoning and objective of this new study to OTW, “Patients often complain of specific functional disabilities after long lumbar fusion. However, existing evaluation systems used for lumbar spinal disorders are not useful for evaluating specific functional disabilities. This study showed that after long lumbar fusion, a new clinical assessment tool is required for evaluating specific functional disabilities due to lumbar stiffness, especially considering regional cultural habits.”
In other words, said the study authors, “The Oswestry Disability Index (ODI) cannot represent all types of functional disabilities observed after lumbar fusion and a region-specific Functional Disability Index (SFDI) is necessary.”
Therefore, said Dr. Park, it was important to design a study which would “Evaluate changes in specific functional disabilities according to the lumbar fusion length.” As a result, the research team collected data regarding specific functional difficulties that long-fusion patients experience even three years postoperatively as opposed to patients who had short-level fusion surgeries.
For the study, the research team compared postop functioning for 81 patients who’d been treated with ≥3-level lumbar fusion (group I) to 70 age- and sex-matched patients who’d received one- or two-level lumbar fusions (group II). The research team then collected pre- and postop ODI and Visual Analogue Scale (VAS) scores for each patient. They also collected SFDI scores for each patient postoperatively.
The authors also collected mean intergroup preoperative ODI and VAS scores. The authors reported that the ODI and VAS scores were similar and that “mean postoperative intergroup VAS scores were similar; however, the mean postoperative ODI and SFDI scores were significantly higher in group I than in group II at 1-year (P<0.001, P<0.001, respectively) and 3-year follow-up (P = 0.037, P<0.001, respectively).”
“Among 10 ODI items, group I showed significant disability with regard to six items at the 1-year follow-up compared with group II, but only showed significant disability with regard to one item at the 3-year follow-up. Among the 12 SFDI items, group I showed significant disability with regard to all 12 items at 1-year follow-up compared with group II, as well as significant disability with regard to nine items at 3-year follow-up.”
Dr. Park summarized the results from the study to OTW, “Typically, these specific functional disabilities were not present before surgery or were not considered by the spine surgeon. However, depending on occupation or lifestyle, some patients may be more sensitive to specific functional disabilities after long lumbar fusion. Therefore, surgeons should be aware of these specific functional disabilities, and should provide sufficient preoperative information to improve postoperative satisfaction.”
“Surgeons should be careful in choosing the number of fusion levels because the degree of specific functional disability increases according to fusion level. Especially after three years, most of the specific functional disability still remained significantly difficult following, so surgeons should be more carefully when deciding on long lumbar fusion.”
