The Nottingham radiation protocol for O-arm navigation in paediatric deformity patients: a feasibility study.

BACKGROUND: O-arm assisted pedicle screw placement has been proven to be more accurate than free-hand technique. Radiation exposure remains the primary drawback. We determined the feasibility and safety of a reduced radiation protocol in paediatric patients undergoing scoliosis correction. METHODS: A reduced radiation protocol for a medtronic O-arm navigational system was devised. 3D CT reconstructions of an anthropomorphic pelvic phantom indicated adequate image quality after reduction to 14% of current manufacturer default factors. A feasibility study to test the image quality was undertaken on four patients, one with syndromic and three with idiopathic scoliosis each receiving progressively reducing radiation exposure of 60%, 50%, 40% and 14% of what would have been delivered using the manufacturer default protocol. This represented 32% of the mayo clinic protocol. It was achieved by reducing the x-ray tube current to 10 mA while keeping the tube potential at 90 kVp. RESULTS: A low dose O-arm protocol was able to generate adequate image quality while delivering as little as 14% (for lumbar region reconstructions) of the recommended protocol radiation dose. The total radiation dose delivered with this protocol was approximately 0.8 milliSieverts for a single spin. This effective dose represents < 1/3 of average UK and < 1/6 average US annual radiation exposure. There were no neurological or implant-related complications. CONCLUSIONS: Our low dose O-arm radiation protocol significantly reduces the radiation exposure compared to the manufacturer recommended Mayo clinic protocol providing operational image quality to allow accurate screw placement in spinal deformity.

Surgical approaches to L5 corpectomy: a systematic review.

INTRODUCTION: Surgical approaches to pathologies of the L5 vertebra constitute a significant challenge. Our aim was to review the efficacy and safety of the surgical approaches to L5 corpectomy and reconstruction across the range of presenting pathology. MATERIALS AND METHODS: This systematic review was conducted according to PRISMA guidelines, and databases were searched from 1970 to January 2020. The search inclusion criteria were L5 Corpectomy AND/OR Spondylectomy AND/OR Vertebrectomy. The outcome measures studied were length of surgery, blood loss, fusion or failure of fusion/instrumentation, complications and mortality. RESULTS: Initial 36 articles were identified, and final 6 studies met our inclusion criteria. The mean reported blood loss was 2265 ml (400-4700 ml) and was higher for the two-stage posterior-anterior surgery group than the posterior-only surgery group (mean 3230 mls vs. 1260 mls) but not the operative time. All surgical approaches shared high fusion rates (94%) and relatively low complication rates (11.7%). However, surgical strategies incorporating an anterior approach were notable for vascular complications (4-7%), as well as perioperative mortality (9%) not seen in the posterior-only surgery group. CONCLUSION: Where there is clinical and circumstantial equipoise regarding the choice of surgical approaches for a L5 corpectomy, this review indicates a reported mean blood loss of 2265 ml (400-4700 ml), high fusion rates (94%) and relatively low complication rates (11.7%). It is difficult to make direct comparisons between approaches due to small case series, the variability in primary pathology, clinical intent and surgeon experience.

Can Fan-Beam Interactive Computed Tomography Accurately Predict Indirect Decompression in Minimally Invasive Spine Surgery Fusion Procedures?

BACKGROUND: Recently, novel mobile intraoperative fan-beam computed tomography (CT) was introduced, allowing for real-time navigation and immediate intraoperative evaluation of neural decompression in spine surgery. This study sought to investigate whether intraoperatively assessed neural decompression during minimally invasive spine surgery (MISS) has a predictive value for clinical and radiographic outcome. METHODS: A retrospective study of patients undergoing intraoperative CT (iCT)-guided extreme lateral interbody fusion or transforaminal lumbar interbody fusion was conducted. 1) Preoperative, 2) intraoperative (after cage implantation, 3) postoperative, and 4) follow-up radiographic and clinical parameters obtained from radiography or CT were quantified. RESULTS: Thirty-four patients (41 spinal segments) were analyzed. iCT-based navigation was successfully accomplished in all patients. Radiographic parameters showed significant improvement from preoperatively to intraoperatively after cage implantation in both MISS procedures (extreme lateral interbody fusion/transforaminal lumbar interbody fusion) (P ≤ 0.05). Radiologic parameters for both MISS fusion procedures did not show significant differences to the assessed radiographic measures at follow-up (P > 0.05). Radiologic outcome values did not decrease when compared intraoperatively (after cage implantation) to latest follow-up. CONCLUSIONS: Intraoperative fan-beam CT is capable of assessing neural decompression intraoperatively with high accuracy, allowing for precise prediction of radiologic outcome and earliest possible feedback during MISS fusion procedures. These findings are highly valuable for routine practice and future investigations toward finding a threshold for neural decompression that translates into clinical improvement. If sufficient neural decompression has been confirmed with iCT imaging studies, additional postoperative and/or follow-up imaging studies might no longer be required if patients remain asymptomatic.

"One-Shot" CT image navigated circumferential fusion in a single lateral decubitus position: surgical technique.

The purpose of this paper was to summarize the surgical peculiarities of a combined approach for minimally invasive lateral retroperitoneal interbody fusion and posterior percutaneous pedicle screw instrumentation in the same lateral decubitus position using intraoperative computed tomography-based navigation.