Browsing by Author "Safaee, Michael M"

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    Predictive Modeling of Length of Hospital Stay Following Adult Spinal Deformity Correction: Analysis of 653 Patients with an Accuracy of 75% within 2 Days.
    (World neurosurgery, 2018-07) Safaee, Michael M; Scheer, Justin K; Ailon, Tamir; Smith, Justin S; Hart, Robert A; Burton, Douglas C; Bess, Shay; Neuman, Brian J; Passias, Peter G; Miller, Emily; Shaffrey, Christopher I; Schwab, Frank; Lafage, Virginie; Klineberg, Eric O; Ames, Christopher P; International Spine Study Group
    Length of stay (LOS) after surgery for adult spinal deformity (ASD) is a critical period that allows for optimal recovery. Predictive models that estimate LOS allow for stratification of high-risk patients.A prospectively acquired multicenter database of patients with ASD was used. Patients with staged surgery or LOS >30 days were excluded. Univariable predictor importance ≥0.90, redundancy, and collinearity testing were used to identify variables for model building. A generalized linear model was constructed using a training dataset developed from a bootstrap sample; patients not randomly selected for the bootstrap sample were selected to the training dataset. LOS predictions were compared with actual LOS to calculate an accuracy percentage.Inclusion criteria were met by 653 patients. The mean LOS was 7.9 ± 4.1 days (median 7 days; range, 1-28 days). Following bootstrapping, 893 patients were modeled (653 in the training model and 240 in the testing model). Linear correlations for the training and testing datasets were 0.632 and 0.507, respectively. The prediction accuracy within 2 days of actual LOS was 75.4%.Our model successfully predicted LOS after ASD surgery with an accuracy of 75% within 2 days. Factors relating to actual LOS, such as rehabilitation bed availability and social support resources, are not captured in large prospective datasets. Predictive analytics will play an increasing role in the future of ASD surgery, and future models will seek to improve the accuracy of these tools.
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    Proximal Junctional Kyphosis Prevention Strategies: A Video Technique Guide.
    (Operative neurosurgery (Hagerstown, Md.), 2017-10) Safaee, Michael M; Osorio, Joseph A; Verma, Kushagra; Bess, Shay; Shaffrey, Christopher I; Smith, Justin S; Hart, Robert; Deviren, Vedat; Ames, Christopher P
    BACKGROUND:Proximal junctional kyphosis (PJK) is a well-recognized complication in patients undergoing posterior instrumented fusion procedures for adult spinal deformity. Strategies that reduce rates of PJK have the potential to improve the safety of these operations and decrease cost by eliminating the need for revision surgery. OBJECTIVE:To present a set of surgical techniques that can decrease rates of PJK in adults undergoing surgery for spinal deformity. METHODS:We summarize the use of vertebroplasty, transverse process hooks, terminal rod contouring, and ligament augmentation as means to reduce rates of PJK. RESULTS:We present PJK prevention strategies and a video technique guide that are safe, technically feasible, and add minimal operative time to these surgical procedures. When applied to appropriate high-risk patients, these techniques have the potential to dramatically reduce rates of PJK, which improves quality of life and decreases the cost associated with this treating adult spinal deformity. CONCLUSION:PJK prevention strategies represent a critical area for improvement in surgery for adult spinal deformity. We present a summary of techniques that are safe, feasible, and add minimal time to the overall procedure. These techniques warrant investigation in a thoughtful, prospective manner, but are supported by existing data and compelling biomechanical rationale. Our hope is that these strategies can be applied, particularly in high-risk patients, to help reduce rates of PJK.
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    Utility of neuromonitoring during lumbar pedicle subtraction osteotomy for adult spinal deformity.
    (Journal of neurosurgery. Spine, 2019-05) Lau, Darryl; Dalle Ore, Cecilia L; Reid, Patrick; Safaee, Michael M; Deviren, Vedat; Smith, Justin S; Shaffrey, Christopher I; Ames, Christopher P

    Objective

    The benefits and utility of routine neuromonitoring with motor and somatosensory evoked potentials during lumbar spine surgery remain unclear. This study assesses measures of performance and utility of transcranial motor evoked potentials (MEPs) during lumbar pedicle subtraction osteotomy (PSO).

    Methods

    This is a retrospective study of a single-surgeon cohort of consecutive adult spinal deformity (ASD) patients who underwent lumbar PSO from 2006 to 2016. A blinded neurophysiologist reviewed individual cases for MEP changes. Multivariate analysis was performed to determine whether changes correlated with neurological deficits. Measures of performance were calculated.

    Results

    A total of 242 lumbar PSO cases were included. MEP changes occurred in 38 (15.7%) cases; the changes were transient in 21 cases (55.3%) and permanent in 17 (44.7%). Of the patients with permanent changes, 9 (52.9%) had no recovery and 8 (47.1%) had partial recovery of MEP signals. Changes occurred at a mean time of 8.8 minutes following PSO closure (range: during closure to 55 minutes after closure). The mean percentage of MEP signal loss was 72.9%. The overall complication rate was 25.2%, and the incidence of new neurological deficits was 4.1%. On multivariate analysis, MEP signal loss of at least 50% was not associated with complication (p = 0.495) or able to predict postoperative neurological deficits (p = 0.429). Of the 38 cases in which MEP changes were observed, the observation represented a true-positive finding in only 3 cases. Postoperative neurological deficits without MEP changes occurred in 7 cases. Calculated measures of performance were as follows: sensitivity 30.0%, specificity 84.9%, positive predictive value 7.9%, and negative predictive value 96.6%. Regarding the specific characteristics of the MEP changes, only a signal loss of 80% or greater was significantly associated with a higher rate of neurological deficit (23.0% vs 0.0% for loss of less than 80%, p = 0.021); changes of less than 80% were not associated with postoperative deficits.

    Conclusions

    Neuromonitoring has a low positive predictive value and low sensitivity for detecting new neurological deficits. Even when neuromonitoring is unchanged, patients can still have new neurological deficits. The utility of transcranial MEP monitoring for lumbar PSO remains unclear but there may be advantages to its use.