Tyler J. Jenkins

Differences in bone mineral density of fixation points between lumbar cortical and traditional pedicle screws

BACKGROUND CONTEXT The use of a novel lumbar pedicle cortical bone trajectory (CBT) screw has recently gained popularity, allowing for a minimally invasive approach and potentially improved screw purchase. However, to date, no studies have identified the ideal patient population to utilize this technology. PURPOSE This study reports the bone mineral density (BMD) using Hounsfield units (HUs) along a CBT screw pathway. Patients with a greater difference in density of bone in the lumbar vertebrae between the fixation points of the CBT and traditional pedicle screw may be optimal candidates to realize the advantages of this technique. STUDY DESIGN/SETTING A cross-sectional observational anatomic study was carried out. PATIENT SAMPLE The sample comprised 180 randomly selected patients with lumbar computed tomography imaging from L1 to L5 spinal levels. OUTCOME MEASURES This study used computed tomography image-derived HUs as a metric for BMD. METHODS A total of 180 patients without previous lumbar surgery with computed tomography imaging of the lumbar spine met the inclusion criteria. Patients were chosen randomly from an institutional database based on age (evenly distributed by decade of life) and gender. Hounsfield units were measured at the expected end fixation point for both a cortical (superior/posterior portion of the vertebral body) and traditional pedicle trajectory (mid-vertebral body). RESULTS Hounsfield unit values measured at the end fixation point for the CBT screw were significantly greater than that of the traditional pedicle screw in all age groups. The relative difference in HU values significantly increased with each decade of age (p<.001) and caudal lumbar level (p<.001). In the osteoporotic group, as determined by well-established HU values, there was a significantly greater difference in the BMD of the CBT fixation point compared with the traditional trajectory (p=.048-<.001). CONCLUSIONS Bone mineral density as measured by HU values for the fixation point of the CBT screw is significantly greater than that of the traditional pedicle screw. This difference is even more pronounced when comparing osteoporotic and elderly patients to the general population. The data in this study suggest that the potential advantages from the CBT screw such as screw purchase may increase linearly with age and in osteoporotic patients.

Preoperative predictors of increased hospital costs in elective anterior cervical fusions: a single-institution analysis of 1,082 patients

BACKGROUND CONTEXT The frequency of anterior cervical fusion (ACF) surgery and total hospital costs in spine surgery have substantially increased in the last several years. PURPOSE To determine which patient comorbidities are associated with increased total hospital costs after elective one- or two-level ACFs. STUDY DESIGN/SETTING Retrospective cohort analysis. PATIENT SAMPLE Individuals who have undergone elective one- or two-level ACFs at our single institution. The total number of patients amounted to 1,082. OUTCOME MEASURES Total hospital costs during single admission. METHODS Multivariate linear regression models were used to analyze independent effects of preoperative patient characteristics on total hospital costs. Univariate analysis was used to examine association of these characteristics on operative time, length of hospital stay (LOS), and complications. RESULTS Age, obesity, and diabetes were independently associated with increased average hospital costs of

Vertebral Osteomyelitis and Spinal Epidural Abscess: An Evidence-based Review.

1,404 (95% confidence interval [CI],

Surgical Site Infections in Spinal Surgery.

857-

The Triangle Model of Congenital Cervical Stenosis.

1,951; p<.001),

Injectable gelatin used as hemostatic agent to stop pedicle bleeding in long deformity surgical procedures: does it embolize?

681 (95% CI,

Iatrogenic Flatback and Flatback Syndrome

285-

Is Polymethyl Methacrylate a Viable Option for Salvaging Lateral Mass Screw Failure in the Subaxial Cervical Spine

1,076; p=.001), and

The use of a novel tablet application to quantify dysfunction in cervical spondylotic myelopathy patients

1,877 (95% CI,

Management of Lumbar Conditions in the Elite Athlete

726-