Combining pedicle screw stimulation with spinal navigation, a protocol to maximize the safety of neural elements and minimize radiation exposure in thoracolumbar spine instrumentation.

PURPOSE: The O-arm-based navigation increases the accuracy of pedicle screw positioning and offers the possibility of performing a 3D scan before wound closure. However, repeating the 3D scan exposes the patient to additional radiation. We combined O-arm navigation with pedicle screw (PS) stimulation followed by a 3D scan to evaluate their accuracy and aimed for the creation of a protocol that maximizes the safety and minimizes radiation. METHODS: Patients had pedicle screws insertion using O-arm spinal navigation, then had PS triggered electromyography (EMG), and finally a 3D scan to evaluate the accuracy of screw position. RESULTS: 447 screws were inserted in 71 patients. In 10 patients, 11 screws needed repositioning. Comparing results of PS triggered EMG responses to the 3D scan, we found: (a) negative stimulation response with negative 3D scan findings, corresponding to 432 acceptable screw position (96.6 %) in 58 patients (81.7 %). In these cases, the redo 3D scan could be avoided. (b) Positive stimulation response with positive 3D scan findings, corresponding to 7 unacceptable screw position (1.5 %) in 6 patients (8.4 %). In these cases, PS stimulation detected malpositioned screws that would be missed without a redo 3D scan. CONCLUSION: We propose a protocol of routinely performing PS stimulation after screw insertion using spinal navigation. In case of positive stimulation, a 3D scan must be performed to rule out a probable screw mal position (6 patients 8.4 %). However, in case of negative stimulation, redo 3D scan can be avoided in 81.7 % of patients.

Deep venous thrombosis in spine surgery patients: incidence and hematoma formation.

Deep venous thrombosis (DVT) is a significant health care problem; a variety of factors place spinal surgery patients at high risk for DVT. Our aim is to define the incidence of DVT occurrence in spite of prophylactic measures (mechanical and chemoprophylaxis), and the development of spinal epidural hematoma as a complication of chemoprophylaxis. In a single-center prospective study, 158 patients who underwent spinal surgical procedures were evaluated by clinical evaluation and lower limb Doppler ultrasonography imaging. Only one patient (0.6%) developed DVT; this patient was treated successfully without thrombus progression, with full recanalization. Three patients (1.8%) developed spinal epidural hematoma, but only one required surgical evacuation, and none sustained neurologic deficit. Careful evaluation for DVT risk on an individual basis and good prophylaxis helps to minimize the risk of DVT. The neurosurgeon is thus left to weigh the risks of postoperative hematoma formation against the benefits of protecting against DVT.

Recovery of third nerve palsy after endovascular treatment of posterior communicating artery aneurysms.

BACKGROUND: High recovery rates after endovascular treatment of TNP-inducing PcomA aneurysms have been reported. However, only few and often small series were reported. The results of the 2 available comparative studies are controversial. Choosing clipping or coiling as treatment modality nowadays is still a matter of debate. We report the ophthalmologic outcome of 20 consecutive patients treated by coiling of TNP-inducing PcomA aneurysms. METHODS: The third nerve function before and after endovascular treatment was assessed and studied retrospectively. Predictive recovery factors known from literature including treatment timing, the degree of preoperative nerve deficit, the association with SAH, coil type, cardiovascular risk factors, and age were analyzed. A review of the literature was performed. RESULTS: Eight patients presented initially with complete nerve palsy (40%) and 12 with partial palsy (60%). Eleven patients had SAH. The mean aneurysm size was 7.14 mm; there were no partially thrombosed aneurysms. Of the 20 patients, 19 (95%) recovered. Recovery was complete in 7 patients (35%), partial in 12 patients (60%), and 1 patient remained unchanged (5%). The mean duration of follow-up was 24.7 months. One patient with complete TNP recovered completely after 5 months of coiling. One case of late complete nerve recovery was observed at 20 months. No cases of reoccurrences or worsening of the partial TNP were observed, including patients who developed recanalization of the aneurysmal sac. Clinical presentation with SAH and early management were statistically significant factors that positively influenced nerve recovery (P = .006549 and P = .015718, respectively). Initial partial TNP seems to influence recovery but did not reach significance (P = .079899). CONCLUSION: Coiling of PcomA aneurysms is associated with high rates of third nerve function recovery. Complete recovery can be expected even after long periods and in cases of initial complete nerve palsy. The early treatment and the association with SAH seem to promote the nerve recovery.