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  • Author or Editor: Konrad Knusel x
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The effect of C2–3 disc angle on postoperative adverse events in cervical spondylotic myelopathy

Presented at the 2018 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

Bryan S. Lee, Kevin M. Walsh, Daniel Lubelski, Konrad D. Knusel, Michael P. Steinmetz, Thomas E. Mroz, Richard P. Schlenk, Iain H. Kalfas and Edward C. Benzel

OBJECTIVE

Complete radiographic and clinical evaluations are essential in the surgical treatment of cervical spondylotic myelopathy (CSM). Prior studies have correlated cervical sagittal imbalance and kyphosis with disability and worse health-related quality of life. However, little is known about C2–3 disc angle and its correlation with postoperative outcomes. The present study is the first to consider C2–3 disc angle as an additional radiographic predictor of postoperative adverse events.

METHODS

A retrospective chart review was performed to identify patients with CSM who underwent surgeries from 2010 to 2014. Data collected included demographics, baseline presenting factors, and postoperative outcomes. Cervical sagittal alignment variables were measured using the preoperative and postoperative radiographs. Univariable logistic regression analyses were used to explore the association between dependent and independent variables, and a multivariable logistic regression model was created using stepwise variable selection.

RESULTS

The authors identified 171 patients who had complete preoperative and postoperative radiographic and outcomes data. The overall rate of postoperative adverse events was 33% (57/171), and postoperative C2–3 disc angle, C2–7 sagittal vertical axis, and C2–7 Cobb angle were found to be significantly associated with adverse events. Inclusion of postoperative C2–3 disc angle in the analysis led to the best prediction of adverse events. The mean postoperative C2–3 disc angle for patients with any postoperative adverse event was 32.3° ± 17.2°, and the mean for those without any adverse event was 22.4° ± 11.1° (p < 0.0001).

CONCLUSIONS

In the present retrospective analysis of postoperative adverse events in patients with CSM, the authors found a significant association between C2–3 disc angle and postoperative adverse events. They propose that C2–3 disc angle be used as an additional parameter of cervical spinal sagittal alignment and predictor for operative outcomes.

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The efficacy of intraoperative multimodal monitoring in pedicle subtraction osteotomies of the lumbar spine

Presented at the 2019 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

Jianning Shao, Maxwell Y. Lee, Shreya Louis, Konrad Knusel, Bryan S. Lee, Dominic W. Pelle, Jason Savage, Joseph E. Tanenbaum, Thomas E. Mroz and Michael P. Steinmetz

OBJECTIVE

Iatrogenic spine injury remains one of the most dreaded complications of pedicle subtraction osteotomies (PSOs) and spine deformity surgeries. Thus, intraoperative multimodal monitoring (IOM), which has the potential to provide real-time feedback on spinal cord signal transmission, has become the gold standard in such operations. However, while the benefits of IOM are well established in PSOs of the thoracic spine and scoliosis surgery, its utility in PSOs of the lumbar spine has not been robustly documented. The authors’ aim was to determine the impact of IOM on outcomes in patients undergoing PSO of the lumbar spine.

METHODS

All patients older than 18 years who underwent lumbar PSOs at the authors’ institution from 2007 to 2017 were analyzed via retrospective chart review and categorized into one of two groups: those who had IOM guidance and those who did not. Perioperative complications were designated as the primary outcome measure and postoperative quality of life (QOL) scores, specifically the Parkinson’s Disease Questionnaire–39 (PDQ-39) and Patient Health Questionnaire–9 (PHQ-9), were designated as secondary outcome measures. Data on patient demographics, surgical and monitoring parameters, and outcomes were gathered, and statistical analysis was performed to compare the development of perioperative complications and QOL scores between the two cohorts. In addition, the proportion of patients who reached minimal clinically important difference (MCID), defined as an increase of 4.72 points in the PDQ-39 score or a decrease of 5 points in the PHQ-9 score, in the two cohorts was also determined.

RESULTS

A total of 95 patients were included in the final analysis. IOM was not found to significantly impact the development of new postoperative deficits (p = 0.107). However, the presence of preoperative neurological comorbidities was found to significantly correlate with postoperative neurological complications (p = 0.009). Univariate analysis showed that age was positively correlated with MCID achievement 3 months after surgery (p = 0.018), but this significance disappeared at the 12-month postoperative time point (p = 0.858). IOM was not found to significantly impact MCID achievement at either the 3- or 12-month postoperative period as measured by PDQ-39 (p = 0.398 and p = 0.156, respectively). Similarly, IOM was not found to significantly impact MCID achievement at either the 3- or 12-month postoperative period, as measured by PHQ-9 (p = 0.230 and p = 0.542, respectively). Multivariate analysis showed that female sex was significantly correlated with MCID achievement (p = 0.024), but this significance disappeared at the 12-month postoperative time point (p = 0.064). IOM was not found to independently correlate with MCID achievement in PDQ-39 scores at either the 3- or 12-month postoperative time points (p = 0.220 and p = 0.097, respectively).

CONCLUSIONS

In this particular cohort, IOM did not lead to statistically significant improvement in outcomes in patients undergoing PSOs of the lumbar spine (p = 0.220). The existing clinical equipoise, however, indicates that future studies in this arena are necessary to achieve systematic guidelines on IOM usage in PSOs of the lumbar spine.