Cervical Spine Fracture Fixation - Steve Corbett 28/8/2001

INTRODUCTION

The lower cervical spine begins with the caudal half of theC2 vertebral body and ends with the T1 segment. It relies on the functionalintegrity of the soft tissues to maintain balanced alignment and to ensureproper neurological function. Important soft tissue structures include the intervertebral discs and their respective endplates, the facet capsules, theanterior and posterior ligaments and the interspinous ligaments.

Cervical spine is more prone to injury than the back as the bony structures are small I size, the spinal segments have high mobility and the head represents a relatively large mass tethered to the free end of the spinal column.

Most injuries are indirect with severity of injury dependenton age, bone mineral quality, preexisting ligament laxity, spinal ankylosis andspinal canal diameter.

2 – 5 % patients with blunt trauma sustain fracture ordislocation of cervical spine. Incidence of penetrating trauma is on theincrease.

No universally accepted classification system :

AO/ASIF : Type A– axial load : stable = simple compression fracture, teardrop, isolated spinous process

Type B – bending : unstable = unilateral / bilateral facet dislocation, unstable extension fracture dislocation

Type C – circumferential : highly unstable = flexion teardrop, unstable burst fracture

Mechanistic: Distraction flexion

Vertical compression

Compressive flexion

Compressive extension

Distractive extension

Lateral flexion

Patterns ofinjury

1. C3 – C7 compression fracture

due to flexion forces

most often at C4-5 C5-6

canal compromise is rare

if translation greater thn 3.5 mm orangulation greater than 11 degrees then considered unstable

2. C3 – C7 burst fractures

due to compression flexion or axial load

most often to C5 C6

often canal compromise from posterior wall involvement and possible neurological injury

3. Others

lateral mass fracture involving pedicles and ipsilateral lamina

spinous processes

Treatment

Non –operative : collars, cervicothoracic braces (sterno occiput mandibular immobilisation [SOMI], Minerva), skeletal traction, halo ring, steroids

Operative :anterior, posterior, combined

ANTERIOR APPROACH

Left sided Smith-Robinsonapproach

Centred over the the fracture body with level determined by comparison of surface anatomy of thyroid and cricoid cartilage with their positions on a lateral Xray. The carotid tubercle is located at C6 with cricoid cartilage also at C6 level.