Identifying cervical spine injuries in confused or comatose patients
with multiple injuries provides a diagnostic challenge. Our aim
was to investigate the protocols which are used for the clearance
of the cervical spine in these patients in English hospitals. All hospitals in England with an Emergency Department were asked
about the protocols which they use for assessing the cervical spine.
All 22 Major Trauma Centres (MTCs) and 141 of 156 non-MTCs responded
(response rate 91.5%).Aim
Patients and Methods
Different methods of lateral mass(LM) screw placement in the cervical spine have been described. In the axial plane, 30 degrees is the recommended angle to avoid neurovascular injury. The estimation of this angle remains arbitrary and operator dependant. To assess how accurately the lateral trajectory angle (LTA) for cervical LM screws is achieved by visual estimation amongst experienced spinal surgeons. A sawbone model of cervical spine with simulated lordosis was used. Five spinal consultants and five senior spinal fellows were asked to insert 1.6 mm K wires into lateral masses of C3 to C6 bilaterally to simulate screws. The LTA in transverse plane was measured using a customised protractor. Basic statistical analyses of all the data were obtained. Using all the angles derived, a virtual screw trajectory was drawn in the lateral plane, on a normal axial Computerised Tomography scan of cervical spine of an anonymous patient using PACS system. The overall mean LTA for the group was 25.15 degrees, that of the fellows 24.4 and consultants 26.2 degrees. Mean deviation from 30 degrees for fellows was 5.2 and 6.4 degrees for consultants. Overall standard deviation was 4.78, for fellows and consultants it was 3.3 and 5.8 respectively. Two episodes of vertebral artery injury occurred at 15 and 16 degrees with simulated angles on CT. A moderate variability in visual estimation of the trajectory angle exists even amongst experienced surgeons during insertion of cervical LM screws. An anatomical landmark would be useful to improve the reliability of the procedure.
Consecutive case series To evaluate the efficacy of a strict stepwise radioanatomical procedure protocol in avoiding neurological complications through tool malplacement in fluoroscopy guided percutaneous procedures of the thoracic spine. Fluoroscopy guided percutaneous access to thoracic vertebral bodies is technically demanding. There is a trend towards computed tomography (CT) guidance on grounds of perceived lesser risk of spinal canal instrument malplacement. CT is however not always readily accessible and a safe technique for fluoroscopy guided procedures therefore desirable. 350 consecutive fluoroscopy guided percutaneous procedures (biopsy, vertebroplasty or kyphoplasty) covering all thoracic vertebral levels T1-T12 were performed according to a strict stepwise radioanatomical protocol. The crucial step of the protocol was not to advance the tool beyond the anterior-posterior (ap) projection of the medial pedicle wall until the tip of the instrument had been verified to have reached the posterior vertebral cortex in the lateral projection. The neurological status of patients was assessed through clinical examination prior to, immediately after the procedure and before discharge. Percutaneous instrument placement in the targeted thoracic vertebral body was achieved in all cases and the stepwise radioanatomical protocol was followed in all cases. There was no case of neurological deterioration in the case series. Conclusion: Attention to radiographic landmarks, specifically not crossing the ap projection of the medial pedicle cortex prior to reaching the posterior vertebral wall in the lateral projection, allows neurologically safe performance of fluoroscopy guided percutaneous procedures of the thoracic spine. This simple protocol is particularly useful when access to CT is limited.
