Improved Accuracy of Minimally Invasive Transpedicular Screw Placement in the Lumbar Spine With 3-Dimensional Stereotactic Image Guidance: A Comparative Meta-Analysis.

STUDY DESIGN: This study compares the accuracy rates of lumbar percutaneous pedicle screw placement (PPSP) using either 2-dimensional (2-D) fluoroscopic guidance or 3-dimensional (3-D) stereotactic navigation in the setting of minimally invasive spine surgery (MISS). This represents the largest single-operator study of its kind and first comprehensive review of 3-D stereotactic navigation in the setting of MISS. OBJECTIVE: To examine differences in accuracy of lumbar pedicle screw placement using 2-D fluoroscopic navigation and 3-D stereotaxis in the setting of MISS. SUMMARY OF BACKGROUND DATA: Surgeons increasingly rely upon advanced image guidance systems to guide minimally invasive PPSP. Three-dimensional stereotactic navigation with intraoperative computed tomography offers well-documented benefit in open surgical approaches. However, the utility of 3-D stereotaxis in the setting of MISS remains incompletely explored by few studies with limited patient numbers. MATERIALS AND METHODS: A total of 599 consecutive patients underwent minimally invasive lumbar PPSP aided by 3-D stereotactic navigation. Postoperative imaging and medical records were analyzed for patient demographics, incidence and degree of pedicle breach, and other surgical complications. A total of 2132 screw were reviewed and compared with a meta-analysis created from published data regarding the placement of 4248 fluoroscopically navigated pedicle screws in the setting of MISS. RESULTS: In the 3-D navigation group, a total of 7 pedicle breaches occurred in 6 patients, corresponding to a per-person breach rate of 1.15% (6/518) and a per-screw breach rate of 0.33% (7/2132). Meta-analysis comprised of data from 10 independent studies showed overall breach risk of 13.1% when 2-D fluoroscopic navigation was utilized in MISS. This translates to a 99% decrease in odds of breach in the 3-D navigation technique versus the traditional 2-D-guided technique, with an odds ratio of 0.01, (95% confidence interval, 0.01-0.03), P<0.001. CONCLUSIONS: Three-dimensional stereotactic navigation based upon intraoperative computed tomography imaging offers markedly improved accuracy of percutaneous lumbar pedicle screw placement when used in the setting of MISS.

Showered calcific emboli to the brain, the 'salted pretzel' sign, originating from the ipsilateral internal carotid artery causing acute cerebral infarction.

BACKGROUND AND PURPOSE: Unenhanced head CT has become the first line imaging study in the evaluation of suspected acute cerebral ischemia. It is important to identify subtle findings of acute ischemia on this exam to direct appropriate patient management. Summary of Case- We report the first case of multiple pial surface distal internal carotid artery territory calcified emboli causing multifocal cerebral infarctions, likely from a carotid bifurcation source. CONCLUSIONS: Visualization of multiple pial surface calcifications on unenhanced head CT, the 'salted pretzel sign', should raise suspicion for acute infarction from showered calcific emboli.

Endovascular repair of cervical aortic arch aneurysm.

Cervical aortic arch (CAA) is a rare congenital anomaly of the aortic arch. Rarely, CAA is associated with aneurysm of the arch and great vessels. A 32-year-old male patient, previously in good health, presented with 2 weeks of severe chest pain. Radiographic evaluation revealed a CAA with aneurysmal dilation of the distal aortic arch. The aneurysm extended into the left subclavian artery. There was also marked angulation just distal to the aneurysmal portion. The aneurysmal arch and subclavian artery were repaired using a thoracic aortic endograft. An open axillary-to-axillary bypass was performed, and the left axillary artery was ligated proximally. This restored perfusion to the left upper extremity and effectively excluded the aneurysm sac. Immediately postoperatively, the patient's chest pain resolved, and he has remained symptom free. To the authors' knowledge, this is the first reported repair of a cervical arch aneurysm by endovascular technique.