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Intraoperative adenosine is used to induce asystole to facilitate clip ligation of intracranial aneurysms. Typically, 5-10 mg doses are used per administration and approximately 30 mg is used for a given case. An obvious concern with using adenosine is that the patient can remain in asystole or that prolonged hypotension can result in cerebral or cardiovascular ischemia. The upper limit of adenosine administration remains unclear. We present a case of a patient with a large anterior communicating artery aneurysm requiring large doses of adenosine, far exceeding previously reported cases. The patient received a 90 mg dose of adenosine to achieve 5 s of asystole as well as 30 s of hypotension that facilitated vessel dissection and clip application. Moreover, in order to successfully clip his aneurysm, he received a total of 744 mg of adenosine. After each administration of adenosine, his heart rate and blood pressure returned to baseline without the need for chest compressions or other interventions. He tolerated the procedure and had a good neurological outcome. This case is the first report of using such a high dose of adenosine in intracranial aneurysm surgery and suggests that more aggressive administration of adenosine during aneurysm clipping is feasible. Transient hypotension, as seen in this report, can provide surgeons the crucial moments they need to safely secure an aneurysm from circulation. [ABSTRACT FROM AUTHOR]

Background: Percutaneous pedicle screw placement is now commonly used to treat spinal instability. It is imperative, especially at thoracic levels, to avoid damage to adjacent neurovascular structures. Although more technically demanding when compared with the lumbar spine, we believe that the percutaneous placement of thoracic pedicle screws can be performed safely without image-navigation. Purpose: The purpose was to evaluate the safety of percutaneous pedicle screw placement in the thoracic and thoracolumbar spine without image-navigation. Study Design/Setting: A retrospective study at a single institution. Patient Sample: Patients over the age of 18 years who presented with degenerative disease, trauma or tumor that required surgical stabilization. Outcome Measures: Our outcomes included postoperative plain film X-rays and computerized tomography (CT). Materials and Methods: We performed a retrospective study of patients who underwent percutaneous pedicle screw placement without image-navigation between T2 and L2. Results: Between 2005 and 2011, a total of 507 pedicle screws were placed in 120 patients. The indications included trauma (17%), tumor (8%), and degenerative conditions (75%). The mean age was 61.3 years (range: 20-81 years). Fifty-seven percent were male, and 43% were female. The mean blood loss was 297 ± 40 ml. All patients underwent postoperative anterior-posterior and lateral films that showed safe placement of pedicle screws. Moreover, 57% of patients underwent postoperative CT imaging. There was 1 (0.4%) medial breach and 13 (5%) lateral breaches of the pedicle screw patients who underwent CT imaging as read by an independent neuroradiologist. None of the breaches resulted in adverse neurological sequelae either immediately after or at most recent follow-up. Conclusion: Thoracic and thoracolumbar percutaneous pedicle screw placement can be performed safely and accurately without image-navigation. [ABSTRACT FROM AUTHOR]

Study Design: A cadaveric study to determine the accuracy of percutaneous screw placement in the thoracic spine using standard fluoroscopic guidance., Summary of Background Data: While use of percutaneous pedicle screws in the lumbar spine has increased rapidly, its acceptance in the thoracic spine has been slower. As indications for pedicle screw fixation increase in the thoracic spine so will the need to perform accurate and safe placement of percutaneous screws with or without image navigation. To date, no study has determined the accuracy of percutaneous thoracic pedicle screw placement without use of stereotactic imaging guidance., Materials and Methods: Eighty-six thoracic pedicle screw placements were performed in four cadaveric thoracic spines from T1 to T12. At each level, Ferguson anterior-posterior fluoroscopy was used to localize the pedicle and define the entry point. Screw placement was attempted unless the borders of the pedicle could not be delineated solely using intraoperative fluoroscopic guidance. The cadavers were assessed using pre- and postprocedural computed tomography (CT) scans as well as dissected and visually inspected in order to determine the medial breach rate., Results: Ninety pedicles were attempted and 86 screws were placed. CT analysis of screw placement accuracy revealed that only one screw (1.2%) breached the medial aspect of the pedicle by more than 2 mm. A total of four screws (4.7%) were found to have breached medially by visual inspection (three Grade 1 and one Grade 2). One (1.2%) lateral breach was greater than 2 mm and no screw violated the neural foramen. The correlation coefficient of pedicle screw violations and pedicle diameter was found to be 0.96., Conclusions: This cadaveric study shows that percutaneous pedicle screw placement can be performed in the thoracic spine without a significant increase in the pedicle breach rate as compared with standard open techniques. A small percentage (4.4%) of pedicles, especially high in the thoracic spine, may not be safely visualized.