The high rate of adverse events associated with surgical treatment of adult spinal deformity is well-documented, though much less is known about outcomes following non-operative treatment in this population. A large, NIH-funded, multicenter trial comparing surgical to non-operative treatment for adult scoliosis led by Dr. Keith Bridwell has been performed, and results have begun to be published. In the June 1 issue, Dr. Pugely published a paper looking at the effect of serious adverse events (SAEs) on patient reported outcomes in the non-operative treatment group. This group include 105 adult scoliosis patients who were either randomized to or chose non-operative treatment and were followed for 2 years. Thirty-two patients crossed over to surgical treatment and were not included in the analysis. An SAE was defined as death, a life-threatening event, an event causing significant or permanent disability, or a hospitalization. Twenty-seven patients (26%) experienced 42 SAEs, and the majority of these were related to surgery for a problem unrelated to their scoliosis. Four patients experienced an SAE related to taking NSAIDs for their back pain, and these were the only SAEs attributed specifically to scoliosis treatment. At baseline, the SAE and non-SAE groups were similar, with the main differences including the SAE group having a higher BMI (29 vs. 25), a higher proportion of non-white patients (18% vs. 8%), and a higher proportion of non-working patients (56% vs. 29%). Baseline patient reported outcome (PRO) scores were very similar, with the only significant difference being a lower SRS-22 function score for the SAE group. At two year follow-up, the SAE group scored worse on multiple SRS-22 subscales and the SF-12 MCS and PCS.
This is a novel study as it is probably the first that has looked at the rate of SAEs in adult scoliosis patients treated non-operatively. While very few patients suffered any adverse events related to scoliosis or its treatment, this population has a relatively high rate of SAEs related to other medical problems. The adult scoliosis population is older and carries a relatively high comorbidity burden, including a high proportion with other musculoskeletal problems. Twenty six percent of the SAEs were related to hospitalization and surgery for orthopaedic problems or cervical myelopathy. The authors found that sustaining an SAE did have a negative effect on PROs, even though the vast majority of SAEs had nothing to do with scoliosis. This finding is similar to the literature demonstrating the negative effect of non-spinal medical and psychosocial comorbidities on PROs following treatment for other spine conditions.1,2 These results serve as a baseline event of SAEs in the adult scoliosis population, which is helpful when looking at SAEs in the surgical cohort. An interesting side note of this paper is that the majority of patients treated non-operatively did not reach MCID thresholds for improvement on most of the PROs. However, the range of patients reaching MCID varied substantially across the different PROs, from 10% on the Oswestry Disability Index to 54% on the SRS-22 pain subscale. This suggests that the PROs are measuring very different domains or the MCID values may not have been derived in a consistent fashion for the different measures.
Please read Dr. Pugely's paper in the June 1 issue. What do you think about the high rate of SAEs in this population? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
Associate Wed Editor
1. Pearson AM, Lurie JD, Tosteson TD, Zhao W, Abdu WA, Weinstein JN. Who should undergo surgery for degenerative spondylolisthesis? Treatment effect predictors in SPORT. Spine (Phila Pa 1976) 2013;38:1799-811.
2. Slover J, Abdu WA, Hanscom B, Weinstein JN. The impact of comorbidities on the change in short-form 36 and oswestry scores following lumbar spine surgery. Spine (Phila Pa 1976) 2006;31:1974-80.