Patients with cervical spondylotic myelopathy experience maximal improvement in their quality of life, neck disability, myelopathy score, and overall health out to three months following surgical decompression, regardless of their baseline myelopathy severity. This is according to new research, published in the Journal of Neurosurgery: Spine by Connor Berlin (University of Virginia, Charlottesville, USA) et al.
The study did find however that there was an exception with the modified Japanese Orthopaedic Association (mJOA) score in the mild myelopathy cohort, improvement of which “may have been limited by ceiling effect”, according to the researchers. The study findings “will aid surgeons in patient selection, preoperative counselling, and expected postoperative time courses”, they add.
The study sought to determine if retrospective analysis of prospectively collected patient-reported outcomes (PROs) following surgery for cervical spondylotic myelopathy (CSM) differed when stratified by preoperative myelopathy status. Secondary objectives included assessment of the minimal clinically important difference (MCID).
A total of 1,151 patients with CSM were prospectively enrolled from the Quality Outcomes Database at 14 US hospitals. Baseline demographics and PROs at baseline and three and 12 months were measured. These included the modified Japanese Orthopaedic Association (mJOA) score, Neck Disability Index (NDI), quality-adjusted life-years (QALYs) from the EQ-5D, and Visual Analogue Scale from the EQ-5D (EQ-VAS).
Patients were stratified by preoperative myelopathy severity using criteria established by the AO Spine study group: Mild (mJOA score 15–17), moderate (mJOA score 12–14), or severe (mJOA score <12). Univariate analysis was used to identify demographic variables that significantly varied between myelopathy groups. Then, multivariate linear regression and linear mixed regression were used to model the effect of severity and time on PROs, respectively.
The study found that for NDI, EQ-VAS, and QALY, patients in all myelopathy cohorts achieved significant, maximal improvement at three months without further improvement at 12 months. For mJOA, moderate and severe myelopathy groups demonstrated significant, maximal improvement at three months, without further improvement at 12 months.
In addition, the mild myelopathy group did not demonstrate significant change in mJOA score but did maintain and achieve higher PRO scores overall when compared with more advanced myelopathy cohorts. The MCID threshold was reached in all myelopathy cohorts at three months for mJOA, NDI, EQ-VAS, and QALY, with the only exception being mild myelopathy QALY at three months.
Speaking to Spinal News International, Berlin said: “We believe this study provides new insight into both surgeon and patient expectations when surgery is performed for cervical myelopathy. Regardless of an anterior, posterior, or combined approach, regardless of preoperative functional status or myelopathy severity, most of our patients peak in their postoperative recovery at three months.
“Conventional wisdom and prior studies have shown that improvement probably doesn’t peak past one year postoperatively. We demonstrate that time point is closer to three-months without further improvements in most patients at one year.
“This will aid surgeons in counselling their patients for expected postoperative recovery time courses and help better frame patient expectations. It may also indicate whether further interventions are needed if patients do not perceive postoperative improvement in a timely manner.”