36. Deterioration after surgery for degenerative cervical myelopathy: an observational study from the Canadian Spine Outcomes and Research Network

BACKGROUND CONTEXT

Postoperative neurological deterioration is one of the most undesirable complications that can occur after surgery for degenerative cervical myelopathy (DCM).

PURPOSE

To investigate the incidence, etiology, and outcomes of patients who experience neurological deterioration after surgery for DCM.

STUDY DESIGN/SETTING

We analyzed data from the Canadian Spine Outcomes and Research Network (CSORN) DCM prospective cohort study.

PATIENT SAMPLE

We identified 428 patients with DCM who underwent surgery.

OUTCOME MEASURES

mJOA, adverse events, NPRS, NDI, SF12, EQ5D.

METHODS

We defined postoperative neurological deterioration as any decrease in modified Japanese Orthopaedic Association (mJOA) score by at least one point from baseline to 3 months after surgery. Adverse events were collected using the Spinal Adverse Events Severity (SAVES) protocol. Secondary outcomes included patient-reported pain, disability, and health-related quality of life.

RESULTS

Among a study cohort of 428 patients, 50 (12%) deteriorated by at least one mJOA point after surgery for DCM (21 by 1 point, 15 by 2 points, and 14 by three points or more). Significant risk factors included older age, female sex, and milder disease. Among those who deteriorated, 13 experienced contributing intra- or postoperative adverse events, 6 had alternative non-DCM diagnoses, and 31 did not have an identifiable reason for deterioration. Patients who deteriorated had significantly lower mJOA scores at one year after surgery (13.5 (SD 2.7) vs 15.2 (SD 2.2), p<0.01) and those with larger deteriorations were less likely to recover their mJOA to at least their preoperative baseline, but most secondary measures of pain, disability, and health-related quality of life were unaffected.

CONCLUSIONS

The incidence of deterioration of mJOA scores after surgery for DCM was approximately one in ten, but some deteriorations were unrelated to actual spinal cord impairment and most secondary outcomes were unaffected. These findings can inform patient and surgeon expectations during shared decision-making, and they demonstrate that interpretation of mJOA scores without clinical context can sometimes be misleading.

FDA Device/Drug Status

This abstract does not discuss or include any applicable devices or drugs.