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Paul Larson, Peter Nakaji, Walter Stummer, and John Pollina

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Mohamed A. R. Soliman, Asham Khan, John Pollina, and Jeffrey P. Mullin

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Asham Khan, John Pollina, and Jeffrey P. Mullin

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Simon Morr, Hakeem J. Shakir, Lindsay J. Lipinski, Vassilios G. Dimopoulos, Jody Leonardo, and John Pollina

OBJECT

Vertebral fractures are the most common osteoporotic fracture. Bone density testing and medical treatment with bisphosphonates or parathormone are recommended for all patients with an osteoporotic fracture diagnosis. Inadequate testing and treatment of patients presenting with low-impact fractures have been reported in various specialties. Similar data are not available from academic neurosurgery groups. The authors assessed compliance with treatment and testing of osteoporosis in patients with vertebral compression fractures evaluated by the authors’ academic neurosurgery service, and patient variable and health-systems factors associated with improved compliance.

METHODS

Data for patients who underwent percutaneous kyphoplasty for compression fractures was retrospectively collected. Diagnostic and medical interventions were tabulated. Pre-, intra-, and posthospital factors that had been theorized to affect the compliance of patients with osteoporosis-related therapies were tabulated and statistically analyzed.

RESULTS

Less than 50% of patients with kyphoplasty received such therapies. Age was not found to correlate with other variables. Referral from a specialist rather than a primary care physician was associated with a higher rate of bone density screening, as well as vitamin D and calcium therapy, but not bisphosphonate/parathormone therapy. Patients who underwent preoperative evaluation by their primary care physician were significantly more likely to receive bisphosphonates compared with those only evaluated by a hospitalist. Patients with unprovoked fractures were more likely to undergo multiple surgeries compared with those with minor trauma.

CONCLUSIONS

These results suggest poor compliance with current standard of care for medical therapies in patients with osteoporotic compression fractures undergoing kyphoplasty under the care of an academic neurosurgery service.

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Ioannis Siasios, Eftychia Z. Kapsalaki, Kostas N. Fountas, Aggeliki Fotiadou, Alexander Dorsch, Kunal Vakharia, John Pollina, and Vassilios Dimopoulos

OBJECTIVE

Diffusion tensor imaging (DTI) for the assessment of fractional anisotropy (FA) and involving measurements of mean diffusivity (MD) and apparent diffusion coefficient (ADC) represents a novel, MRI-based, noninvasive technique that may delineate microstructural changes in cerebral white matter (WM). For example, DTI may be used for the diagnosis and differentiation of idiopathic normal pressure hydrocephalus (iNPH) from other neurodegenerative diseases with similar imaging findings and clinical symptoms and signs. The goal of the current study was to identify and analyze recently published series on the use of DTI as a diagnostic tool. Moreover, the authors also explored the utility of DTI in identifying patients with iNPH who could be managed by surgical intervention.

METHODS

The authors performed a literature search of the PubMed database by using any possible combinations of the following terms: “Alzheimer's disease,” “brain,” “cerebrospinal fluid,” “CSF,” “diffusion tensor imaging,” “DTI,” “hydrocephalus,” “idiopathic,” “magnetic resonance imaging,” “normal pressure,” “Parkinson's disease,” and “shunting.” Moreover, all reference lists from the retrieved articles were reviewed to identify any additional pertinent articles.

RESULTS

The literature search retrieved 19 studies in which DTI was used for the identification and differentiation of iNPH from other neurodegenerative diseases. The DTI protocols involved different approaches, such as region of interest (ROI) methods, tract-based spatial statistics, voxel-based analysis, and delta-ADC analysis. The most studied anatomical regions were the periventricular WM areas, such as the internal capsule (IC), the corticospinal tract (CST), and the corpus callosum (CC). Patients with iNPH had significantly higher MD in the periventricular WM areas of the CST and the CC than had healthy controls. In addition, FA and ADCs were significantly higher in the CST of iNPH patients than in any other patients with other neurodegenerative diseases. Gait abnormalities of iNPH patients were statistically significantly and negatively correlated with FA in the CST and the minor forceps. Fractional anisotropy had a sensitivity of 94% and a specificity of 80% for diagnosing iNPH. Furthermore, FA and MD values in the CST, the IC, the anterior thalamic region, the fornix, and the hippocampus regions could help differentiate iNPH from Alzheimer or Parkinson disease. Interestingly, CSF drainage or ventriculoperitoneal shunting significantly modified FA and ADCs in iNPH patients whose condition clinically responded to these maneuvers.

CONCLUSIONS

Measurements of FA and MD significantly contribute to the detection of axonal loss and gliosis in the periventricular WM areas in patients with iNPH. Diffusion tensor imaging may also represent a valuable noninvasive method for differentiating iNPH from other neurodegenerative diseases. Moreover, DTI can detect dynamic changes in the WM tracts after lumbar drainage or shunting procedures and could help identify iNPH patients who may benefit from surgical intervention.

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Jason I. Liounakos, Asham Khan, Karen Eliahu, Jennifer Z. Mao, Christopher R. Good, John Pollina, Colin M. Haines, Jeffrey L. Gum, Thomas C. Schuler, Ehsan Jazini, Richard V. Chua, Eiman Shafa, Avery L. Buchholz, Martin H. Pham, Kornelis A. Poelstra, and Michael Y. Wang

OBJECTIVE

Robotics is a major area for research and development in spine surgery. The high accuracy of robot-assisted placement of thoracolumbar pedicle screws is documented in the literature. The authors present the largest case series to date evaluating 90-day complication, revision, and readmission rates for robot-assisted spine surgery using the current generation of robotic guidance systems.

METHODS

An analysis of a retrospective, multicenter database of open and minimally invasive thoracolumbar instrumented fusion surgeries using the Mazor X or Mazor X Stealth Edition robotic guidance systems was performed. Patients 18 years of age or older and undergoing primary or revision surgery for degenerative spinal conditions were included. Descriptive statistics were used to calculate rates of malpositioned screws requiring revision, as well as overall complication, revision, and readmission rates within 90 days.

RESULTS

In total, 799 surgical cases (Mazor X: 48.81%; Mazor X Stealth Edition: 51.19%) were evaluated, involving robot-assisted placement of 4838 pedicle screws. The overall intraoperative complication rate was 3.13%. No intraoperative implant-related complications were encountered. Postoperatively, 129 patients suffered a total of 146 complications by 90 days, representing an incidence of 16.1%. The rate of an unrecognized malpositioned screw resulting in a new postoperative radiculopathy requiring revision surgery was 0.63% (5 cases). Medical and pain-related complications unrelated to hardware placement accounted for the bulk of postoperative complications within 90 days. The overall surgical revision rate at 90 days was 6.63% with 7 implant-related revisions, representing an implant-related revision rate of 0.88%. The 90-day readmission rate was 7.13% with 2 implant-related readmissions, representing an implant-related readmission rate of 0.25% of cases.

CONCLUSIONS

The results of this multicenter case series and literature review suggest current-generation robotic guidance systems are associated with low rates of intraoperative and postoperative implant-related complications, revisions, and readmissions at 90 days. Future outcomes-based studies are necessary to evaluate complication, revision, and readmission rates compared to conventional surgery.