Impact of preoperative neurological status on perioperative morbidity associated with anterior and posterior cervical fusion.

OBJECT: Cervical spine fusion is performed for various indications in patient populations ranging from young and healthy to aged and frail. Whereas disease pathoanatomy dictates the surgical approach, preoperative neurological status does not necessarily implicate a specific technique. Although one expects anterior decompression to be performed over fewer segments in healthier patients who experience fewer complications and faster recovery, the impact of pre-operative myelopathy on perioperative complications remains unclear. No large-scale study has evaluated rates of common complications for cervical fusion or their association with surgical approach and neurological status.
METHODS: Data for 96,773 patients who underwent cervical fusion for degenerative disease between 1988 and 2003 were collected from the Nationwide Inpatient Sample database. Patients were grouped according to surgical approach (anterior versus posterior) and preoperative neurological status (myelopathic versus nonmyelopathic). Multivariate regression was used to evaluate group effects on selected postoperative complications, length of stay, and disposition at the time of hospital discharge. Although this technique can control for the observed covariates, the absence of key information such as the number of fused levels precludes statistical comparison between patients who underwent anterior or posterior approaches.
RESULTS: In this study the authors confirmed that preoperative neurological status impacts perioperative morbidity. For example, patients who were nonmyelopathic and underwent an anterior approach were 7 years younger than the rest of the cohort, and they had a mortality rate of 0.05%. Transfusion was required in 0.34%, and venous thromboembolism occurred in 0.04%. Conversely, these rates were > 13-fold higher in patients with myelopathy who underwent a posterior approach. Furthermore, independent of approach, preoperative myelopathy is highly prognostic of death, pneumonia, transfusion, infection, length of stay, and posthospital disposition. These outcomes at least doubled, with some increasing > 10-fold.
CONCLUSIONS: This nationwide study clarifies the frequency and associations of inpatient complications encountered when treating cervical spine disease. Whereas immediate complications due to anterior approaches are limited, patients with myelopathy who undergo a posterior approach have a more sobering outlook. This study shows that clinical myelopathy augments rates of complication during cervical fusion, regardless of the approach. The exclusion of pathoanatomical data from the Nationwide Inpatient Sample database, of key importance in guiding the surgical approach, prevents any conclusions being drawn about the merits and disadvantages of anterior versus posterior surgery.