The internal carotid artery and the atlas: anatomical relationship and implications for C1 lateral mass fixation.

PURPOSE: The internal carotid artery (ICA) is potentially at risk during posterior fixation of C1. In this study, we performed a CT-based anatomical analysis of the relationship between the internal carotid artery and the lateral mass of the atlas. METHODS: We analysed 30 CT angiography of the cervical spine, and we measured on both sides the distance of the carotid artery from the midline, distance of the ICA from the anterior cortex of C1 and from the ideal C1 screw entry point. We measured the angle between the sagittal plane passing through the entry point and the tangent line of the vessel. Separated statistical analysis between left and right sides, between male and female patients, and differentiation by age were also performed. RESULTS: Sixty ICAs were studied. The mean distance of the ICA from the midline was 23.3 ± 4.3 mm, with a minimum of 15 mm. The distance between the ICA and the anterior cortical layer of C1 was 4.8 ± 2.7 mm, with a minimum of 1.1 mm. The distance between the screw entry point and the arterial wall was 22.6 ± 2.8 mm, with a minimum of 17.5 mm. The mean angle was 10.4°, with a minimum of 11°. CONCLUSIONS: Although rare, intraoperative lesion of the ICA is reported and the spine surgeon must be aware of this risk. Careful preoperative planning is mandatory and the position of the ICA in relation to C1 must be assessed. The anatomical parameters presented in this paper can be useful to reduce the risk of ICA injury.

Spinal navigation applied to the anterior approach for the resection of thoracic disc herniation: patient series.

BACKGROUND: Thoracic disc herniation (TDH) represents a challenge for spine surgeons. The goal of this study is to report the surgical technique and clinical results concerning the application of navigation to anterior transthoracic approaches. OBSERVATIONS: Between 2017 and 2019, 8 patients with TDH were operated in the lateral decubitus by means of mini-open thoracotomy. An adapted patient referent frame was secured to the iliac wing. The high-speed drill was also navigated. Intraoperative three-dimensional scans were used for level identification, optimized drilling trajectory, and assessment of complete resection. At 12 months follow up, all patients were ambulatory. Seven out of 8 patients (87%) experienced a postoperative neurological improvement. We observed 2 postoperative complications: 1 case of pleural effusion and 1 case of abdominal wall weakness. LESSONS: In order to increase the safety of anterior transthoracic discectomy, the authors applied the concepts of spinal navigation to the thoracotomy setting. The advantages of this technique include decrease in wrong-level procedure, continuous matching of intraoperative and navigation anatomical findings, better exposure of the TDH, optimized vertebral body drilling, and minimized risk of neurological damage. In conclusion, the authors consider spinal navigation as an important resource for the surgical treatment of patients with TDH.

Real-time navigation in spinal surgery: what has changed in surgical practice?

BACKGROUND: The authors have carried out a retrospective study to assess the advantages of real-time spinal navigation with 3D-fluoro images (O-arm® and StealthStation® navigation systems, Medtronic, Minneapolis, MN, USA) versus fluoroscopy in spinal surgery. The aim of the study is to ascertain whether this technology has affected surgical indications and clinical practice. METHODS: From January 2009 to December 2013, 421 patients underwent image-guided spinal surgery procedures in our department. They were divided into two main groups: group 1: operated on with C-arm fluoroscopic control; group 2: operated on with real-time navigation with 3D-fluoro images. All patients with vertebral osteosynthesis underwent a postoperative CT scan to check the final position of the screws. RESULTS: The screw misplacement proved to be 5.8% in group 1 and 1.5% in group 2. The odds ratio was 4.2 (95% confidence interval 2.3-7.5) with statistical significance (P<0.0001). The results clearly show an increased number of percutaneous procedures in group 2, as well as longer open osteosynthesis. CONCLUSIONS: Navigation with 3D-fluoro images reduces screw misplacement, facilitates osteosynthesis in the most difficult vertebral segments and allows broader use of percutaneous techniques, when indicated.

Intraoperative Spinal Navigation for the Removal of Intradural Tumors: Technical Notes.

BACKGROUND: In recent years, spinal surgery has incorporated the many advantages of navigation techniques to facilitate the placement of pedicle screws during osteosynthesis, mainly for degenerative diseases. However, spinal intradural tumors are not clearly visible by intraoperative fluoroscopy or computed tomography scans, thereby making navigation necessary. OBJECTIVE: To evaluate the use of spinal navigation for the removal of intradural and spinal cord tumors using spinal magnetic resonance imaging (MRI) merged with intraoperative 3-dimensional (3-D) fluoro images. METHODS: After fixing the patient reference frame on the spinous process, the 3-D fluoro images were obtained in the surgical room. Using this image as the reference, the preoperative volumetric MRI images and intraoperative 3-D fluoro images were merged using automated software or manually. RESULTS: From January to July 2016, we performed 10 navigated procedures for intradural spinal tumors by merging MRI and 3-D fluoro images. Nine patients had an intradural extramedullary tumor, 6 had neurinomas, and 3 had meningiomas; 1 patient had an intramedullary spinal cord metastasis. CONCLUSION: The surgically demonstrated benefits of spinal navigation for the removal of intradural tumors include the decreased risk of surgery at the wrong spinal level, a minimal length of skin incision and muscle strip, and a reduction in bone removal extension. Furthermore, this technique offers the advantage of opening the dura as much as is necessary and, in the case of intrinsic spinal cord tumors, it allows the tumor to be centered. Otherwise, this would not be visible, thus enabling the precise level and the posterior midline sulcus to be determined when performing a mielotomy.

Management of nontraumatic intracranial hemorrhage.

The modern treatment of spontaneous intracranial hemorrhages requires a multidisciplinary approach including neurosurgery, interventional neuroredicology, vascular neurology and radiosurgery to determine the best management strategy.