Introduction

Common procedures used for fixation of the cervical spine.

A. TRACTION

Use of traction for unstable fractures or dislocations of the c-spine.
UNSTABLE injuries as defined by disruption of > 2 of the 3 columns described by Denis
Devices: Mayfield / Gardner-Wells traction Tongs be aware of over distraction in aggressive attempts of reduction

B. ANTERIOR FIXATION of the CERVICAL SPINE

Multiple surgical approaches though anterior is often safer (smaller chance of spinal cord injury).
Possible complications of ANTERIOR approaches:
- injury to vessels (carotid a. /vertebral a. /jugular v.), injury to nerves (X and recurrent laryngeal, spinal cord itself), esophagus, trachea
- other standard c-spine complications (infection, hematoma, graft collapse, non-union)

1. FIXATION OF THE C1 and C2 Special techniques needed to accommodate unusual biomechanics

a. Anterior approaches:

Anterior transoral approach
Anterior lateral retropharyngeal approach utilized

b. Odontoid fractures. Types I, II, III per Anderson classification

Type I (odontoid tip fx)
Type II (waist of odontoid fx) (Most common yet least likely to heal)
Type III (extension of fracture into the base of C2)

Look for use of partially threaded cancellous screws functioning as LAG screws (pull pieces together to aid in healing) ex. Knoringer screw (long lag screw with ends of differing pitches enabling advancement rate into bone to differà pulling of ends together)

May see plate/screws but rare.

If at all possible utilize dynamic imaging (flexion/neutral/extension) to bring out subtle instability in this region.

2. ANTERIOR CERVICAL FUSION

Cloward fusion -- removal of the endplates (and disc) with insertion of bone grafting material.
Smith-Robinson fusion - removal of disc from level of PLL and laterally to joints of Lushka and bone graft placement into disc space. Incorporation at 6-12 weeks
PLATES: Function to aid with instability secondary to DJD, infection, tumor, trauma
- CASPAR plate- trapezoid like shape,
- MORSCHER plate /CLSP plate- H- shaped plate with recess where screw inserts (significantly reduces risk of screws 'backing out') all utilize bicortical screws (should pass anterior & posterior cortices)
- complications of plates: Loosening / 'backing out' / fracturing of screws / 'mass effect' on prevertbral or retropharyngeal soft tissues

POSTERIOR CERVICAL FUSION

OCCIPITAL CERVICAL FUSION:
- O-rings, Luque rectangles see {http://www.eddesign.com/pdfs/Cervical%20Kyphosis.pdf, slide #30} occipital-cervical plates
- Hartshill-Ransford loop utilized in concert with wires and cables of various sorts.
- Cotrel-Dubousset (CD) system or other special plating systems (Roy-Camile) also used
ATLANTOAXIAL (C1-C2) FUSION
- Gallie (wiring of C1-C2 spinous processes),
- Brooks (C1 arch -C2 laminae wiring),
- McLauren fusion (wire around posterior arch of C1 and under C2 spinous process) procedures .i. Use Songer cables (cable with crimped metal collar) or cerclage wires and +/- bone grafting ii. Transarticular screws (cannulated screws (placed over K-wires) through articular pillars of C2 iii. Laminar clamps (Halifax clamps): C-shaped clamps grip lamina with assistance from screws to achive fusion C1-C2 {http://www.thejns-net.org/spine/issues/v92n2/pdf/s0920162.pdf, page 3 of the article}
LOWER C-SPINE POSTERIOR FUSION
- Laminotomy/discectiomy- used for osteophyte and disc decompression at single level
- Laminectomy/Foraminotomy - window of variable size involving lamina alone or [lamina + facet joint] +/- disc removal if bulging is also present
- Laminoplasty- used for patients with OPLL or multisegmental spondylotic myelopathy 1. involves partial resection of spinous processes and laminae (to be used as graft material later), unroofing the posterior spinal canal (various 'open door' or other techniques) and adding 5mm of additional space posteriorly, then repacking the graft material to fill the new space. Additional fixation with wiring and/or methylmethacrylate is often used
- WIRES:
  - 1. Facet wiring -drilling holes into posterior pillars with wires wrapped though the hole and the entire complex encircled with bone graft material
  - 2. Interspinous wiring- drilling holes into spinous processes adjacent to laminae of 2 adjacent vertrebral levels and passing wire from one level to the next
  - 3. Sublaminar wiring - Songer cables or cerclage wires wrapped in a loop around lamina (passing on the inside and outside) of the lamina. Strutted with bone graft to ensure fusion. Rarely seen in low cervical spine due to a small spinal canal diameter
PLATES, CLAMPS, and RODS in POSTERIOR FIXATION
- PLATES utilized over the facet joints and attached to the spine using screws. The screws are angled out into the bone into the lateral mass.
  - Placement of the plates (or clamps) with screws involves some risk to the vertebral artery and the exiting nerve root, so there is added risk (versus wiring procedures), but better fixation of the spine is achieved. These plates all utilize fixation of screws into the articular pillars
  - Tubular plates- concave plate (used more commonly in extremities) sometimes used for long-segment fusions
  - Malleable plates -main use in the pelvis, can be used in spine fusion procedures
  - Haid Plates - proprietary plate, same function as above plates
  - Hook plates - hook on each end to engage lamina with a hole for attachment to articular pillar
- CLAMPS
  - Halifax clamps - proprietary laminar clamps, with hook curves on either end to wrap around lamina. Screw tightens the 2 ends together to engage posterior compression forces. Bone graft often used to facilitate posterior fusion
- RODS
  - CD instrumentation - use reserved typically for very long segment fusion or cervico-thoracic fixation