Introduction: Delayed cervical palsy (DCP) is a recognized complication of cervical spine surgery, most commonly noted at the C5 level. Various theories, such as mechanical stretch or inflammatory responses have been proposed, but the true etiology is unknown. Here we assess the incidence and presence of medical and procedural risk factors correlated with the development of a DCP following cervical spine surgery.
Methods: We retrospectively reviewed 6-years of consecutive cervical decompressions with and without instrumented fusion. In addition to baseline demographics and procedural information, autoimmune risk factors for post-surgical inflammatory neuropathy such as history of autoimmune disease, diabetes, smoking, and blood transfusions were also collected. Univariate and multivariate analysis was performed to identify significant predictors of DCP.
Results: Of 1669 patients, 56 (3.4%) developed a DCP. While the majority of palsies involved C5 (71%), 55% of palsies involved more than one myotome and 18% were bilateral. On univariate analysis, increased risk of DCP was significantly correlated with age (p=0.0061, OR=1.07, 95% CI 1.008-1.050), posterior instrumented fusion (p<0.0001, OR=3.30, 95% CI 1.920-5.653), prone vs. semi-sitting/sitting position (p=0.0036, OR=3.58, 95% CI 1.451-11.881), number of levels (p<0.0001, OR=1.42, 95% CI 1.247-1.605), transfusion (p=0.0231, OR=2.57, 95% CI 1.152-5.132), and non-specific autoimmune disease (p=0.0107, OR=3.83, 95% CI 1.418-8.730). On multivariate analysis, number of operative levels (p=0.0053, OR=1.27, 95% CI 1.075-1.496) and non-specific autoimmune disease (p=0.0416, OR 2.95, 95% CI 1.047-7.092) remained significant. Risk factor analysis was also performed for prevalent procedure categories.
Conclusions: The incidence of DCP is higher in patients undergoing more extensive procedures. While a mechanical etiology is partially supported as a cause for DCP, notable correlations with autoimmune risk factors as well as bilateral and multi-myotomal involvement supports the hypothesis that some DCPs may result from an autoimmune response. The present series suggests that the etiology of DCPs is multifactorial.
Patient Care: Age and history of non-specific autoimmune disease are identified as risk factors for this complication, and could be useful when selecting patients for surgery and counseling them as to the risks of the procedure.
From a surgical perspective, the association of extent of surgery with development of DCP may lead the surgeon to be more conservative with the decompression to decrease the risk of this complication; however, this risk must be weighed against the risk of inadequate decompression resulting in continued symptoms post-operatively.
Additionally, the positioning concerns may lead to specific planning considerations to minimize risk.
Learning Objectives: 1) Delayed cervical palsy is a recognized complication of cervical spine surgery with uncertain etiology
2) The overall incidence of delayed cervical palsy was 3.4%
3) Age, posterior fusion, prone vs. sitting position, number of operative levels, intraoperative transfusion, and non-specific autoimmune disease were all significantly correlated with increased risk of delayed cervical palsy on univariate analysis