Aim

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.

Background: The safest and most effective method of early spine clearance in unconscious patients is the subject of intense debate. Hypothesis: Helical CT is a sufficiently sensitive investigation to render dynamic screening of the cervical spine redundant. Protocol: Our protocol for cervical spinal clearance in the unconscious patient since April 1994 involves the use of plain radiographs, CT scan (helical CT since 1997) and dynamic screening (DS). Method: Over a ten-year period, April 1994 to September 2004, 839 patients were admitted to intensive care under the orthopaedic surgeons. 35 patients were excluded because of incomplete records. Results:. Demographics: The mechanism of injury was a road traffic accident in 80% and the mean ISS was 24.1. There were 95 patients (10.9%) with a cervical spine fracture, 96 (10.8%) with a fracture in either / both thoracic and lumbar regions. Spine clearance: Mean intubation (7.1 days), time to spine clearance (mean 0.4 days). In 318 patients, clearance was performed with the patient conscious (284 prior to intubation, 34 after intubation of < 24hrs). 42 patients (4.6%) died before spine clearance. In 10 patients, the protocol was not followed. Inclusions: 434 patients underwent CT. 10 of the 95 cervical fractures were deemed stable and underwent DS (n = 349). Missed Cases: CT missed 2 cases of instability, one of these (an atlanto-occipital dislocation) was also missed by DS. Critical analysis revealed a Powers ratio calculation would have diagnosed this injury on CT. Sensitivity (CT 97.7% vs DS 98.8%), specificity (100% CT and DS). There were no complications from either procedure. Conclusion: DS is a safe procedure but has no real advantage over helical CT. Power’s ratio calculation is essential to reduce the chance of a missing an upper cervical injury. The cervical spine can be reliably cleared using helical CT alone

Purpose: The biomechanical behaviour of the cervical spine was studied in vitro with an optoelectronic system in order to better understand its physiology. Material: Twenty fresh cervical spines (occiput-D1) from fourteen men and six women, mean age 66.5 years, were sterilised with ß radiation (2.5 Mrad) and stored at −24°C then studied after slow thawing and excision of the paraspinal muscles. Methods: Three-point reflecting markers were rapidly attached to each vertebral segment (4 or 5 vertebrae). The inferior vertebra was blocked. Six pure moment couples (2 N.m maximum, 10 increments) were applied in the three anatomic planes using a loading device lodged on the superior vertebra. Displacements were measured with the VICON 140 using a kinematic software. Results: The three-dimensional behaviour curves of each functional unit (FU) were recorded for each solicitation to analyse the principal movement and coupled movements (maximum mobility, neutral zones, rigid zones, rigidity). Mean maximal flexion-extension movements were C0/C1= 28.7°; C1/C2 = 22.3°; C2/C3 = 7.3°; C3/C4 = 10.6°; C4/C5 = 13.8°; C5/C6 = 13.4°; C6/C7 = 10.8°; C7/T1 = 6.4°. Maximum overall lateral inclinations were: C0/C1= 8.7°; C1/C2 = 9.3°; C2/C3 = 8.7°; C3/C4 = 6.7°; C4/C5 = 10.5°; C5/C6 = 12.2°; C6/C7 = 8.6°; C7/T1 = 5.7°. Maximal overall axial rotations were: C0/C1= 11°; C1/C2 = 71°; C2/C3 = 9.5°; C3/C4 = 10.8°; C4/C5 = 12.3°; C5/C6 = 9°; C6/C7 = 5.6°; C7/T1 = 5.7°. All the FU exhibited flexion-extension movement. Lateral inclination coupled important controlateral rotation for C1/C2 and minimal ipsilateral rotation (< 10°) in the lower FU of the cervical spine. Axial rotation of the C1/T1 functional unit was coupled with homolateral rotation (< 10°). Discussion: Our experimental protocol provided precision of < 1° and good reproducibility allowing simultaneous three-dimensional analysis of the spinal functional units. Making measurements without direct contact is particularly useful for the cervical spine. Our results are within the experimental corridor defined by Goel, Panjabi and Wen. Conclusion: This work on a large number of functional units adds further support to data in the literature concerning the biomechanical behaviour of the cervical spine. Our protocol could be applied to analyse the impact of surgical procedures used for the cervical spine, particularly for the evaluation of new fixation systems or prostheses