Non-instrumented extradural lumbar spine surgery under low-dose acetylsalicylic acid: a comparative risk analysis study.

PURPOSE: Coronary artery disease (CAD) affects over one-third of adults and is the leading cause of overall mortality and morbidity. Acetylsalicylic acid (ASA) is widely used in the prevention of CAD. As the population continues to mature, the number of patients presenting for spinal surgery that are under ASA treatment is rising. Studies investigating the outcome of lumbar spine surgeries without discontinuation of ASA therapy are lacking. The purpose of this study is to evaluate the peri- and postoperative bleeding and cardiovascular complication rates of patients undergoing non-instrumented, extradural, lumbar spine surgery with or without discontinuation of low-dose ASA. METHODS: We retrospectively compared the intra- and postoperative blood loss, morbidity, mortality, blood transfusion requirements and hematologic findings in the ASA group (40 patients) and the control group (62 patients). The diagnosis in all patients was either lumbar disc herniation or spinal canal stenosis. RESULTS: Intraoperative blood loss was 221 ml in the ASA group and 140.16 ml in the control group, showing no statistical difference (p = 0.08). Postoperative blood loss was 146.58 and 167.97 ml in the ASA and control groups, respectively, also without statistical difference (p = 0.76). In the ASA group one patient developed a postoperative epidural hematoma needing revision surgery, while in the control group no postoperative epidural hematomas were seen (p = 0.40). In addition, blood transfusion requirements, hematologic findings, morbidity and mortality showed no significant difference. CONCLUSION: The continuation of ASA treatment in patients undergoing non-instrumented extradural lumbar spinal surgery seems to be safe and its perioperative continuation might therefore be recommended. Further studies confirming these results are needed.

Accuracy of pedicle screw placement in the thoracic and lumbosacral spine using a conventional intraoperative fluoroscopy-guided technique: a national neurosurgical education and training center analysis of 1236 consecutive screws.

OBJECTIVE: Pedicle screw placement is a very common procedure used to stabilize all three columns of the thoracic and lumbar spine. The purpose of this study is to evaluate the incidence of screw misplacement and related complications in patients who underwent fluoroscopy-guided transpedicular screw fixation at a neurosurgical teaching institution. METHODS: We retrospectively reviewed consecutive patients who underwent fluoroscopy-guided transpedicular screw fixation from January 2007 to May 2011 in the Department of Neurosurgery, Kantonsspital Aarau, a certified Swiss National Neurosurgical Education and Training Center. The accuracy of the pedicle screw trajectory was assessed using reconstructed postoperative axial, sagittal, and coronal computed tomography images. The displacement was classified as minor (≤ 2 mm), moderate (2.1-4 mm), and severe (>4 mm). RESULTS: A total of 1236 pedicle screws were placed in 273 consecutive patients in the thoracic and lumbosacral spine. All surgeries were performed under the supervision of 7 board-certified neurosurgeons and faculty members. A total of 17 surgeons, including trainees, participated in all procedures. A total of 247 (20%) screws breaching the pedicle were identified, with 135 (10.9%) minor violations, 65 (5.3%) moderate violations, and 47 (3.8%) severe violations. Sixteen (5.9%) patients developed postoperative radiculopathy. All of these patients belonged to the subgroup of severe screw displacement. CONCLUSIONS: The data presented confirm that for a training and education center, transpedicular fluoroscopy-guided screw fixation remains a technically demanding procedure. As defined in this study, neurological symptoms are likely associated only with severe screw misplacement.