Posterior cervical fusion

The idea

The cervical spine can be reached from the front or from behind, and each suits different problems. From the front, a surgeon can remove a disc or a vertebral body and take pressure directly off the cord, which works very well at one or two levels. From behind, the whole back of the canal can be opened across many levels at once, and very strong fixation can be placed.

A posterior fusion does both from behind. The lamina is removed over the compressed levels so the cord has room, and screws are placed into the lateral masses, the blocks of bone where the joints stack up on either side, then linked with rods. This holds the neck in position while the bone fuses.

Because the lamina has been removed, the levels have to be fused. Without stabilizing, the neck could slowly bend forward over the following years. For necks that do not need stabilizing, laminoplasty is the alternative.

Who this treats

Two of these are the most common reasons for this operation. The first is a neck that needs three, four or five levels decompressed, where doing it all from the front becomes a long operation with a real risk of the fusion failing. The second is a fusion from the front that did not heal. Fixation from behind is much stronger, and it goes through tissue that has not been operated on before.

Front or back: how the approach is chosen

This is decided by where the compression is, how many levels are involved and the alignment of the neck.

The first row matters most. An operation from behind does not remove compression in front of the cord. It makes room behind the cord so it can move back, away from the compression. That works in a neck with its natural forward curve but not in a neck that bends forward, which is why the alignment is corrected as part of the operation where the curve has been lost.

Some necks need both, under one anesthetic or in two stages, as a planned approach for difficult anatomy. See how the approach is chosen.

Fusion or laminoplasty

Both treat cord compression at several levels from behind. A neck that also has pain, instability or a lost curve is fused, and a neck without those problems can have the lamina hinged open instead.

A fusion can correct alignment, treats instability and reliably helps the neck pain that often comes with wear at several levels, but the fused levels lose their motion. A laminoplasty keeps that motion and does not depend on bone healing, but it cannot correct a curve or stabilize the neck, and it does not treat neck pain.

How it’s performed

1. 01

   Positioning

   Face down with the head held in a fixed clamp, the neck set in the alignment the construct is intended to hold. Spinal cord monitoring is running before the position is finalized, so that any change caused by positioning itself is seen at once.

2. 02

   Exposure

   A midline incision, with the muscle taken off the laminae over the levels being instrumented. The muscle attachments at the top are protected where possible, because they help hold the head up afterwards.

3. 03

   Screw placement

   Screws are placed into the lateral masses, and into pedicles at the levels where lateral masses are too small to hold, typically at the bottom of the neck and into the upper thoracic spine. Navigation is used where the anatomy warrants it; the vertebral artery runs close to these trajectories and its position is confirmed on the pre-operative imaging.

4. 04

   Decompression

   The laminae are removed across the compressed levels and the ligament beneath lifted off the cord. Foraminotomies are added where individual roots are pinched as well.

5. 05

   Rods and alignment

   Rods contoured to the intended curve are seated into the screws and the neck is brought to that shape against them. This step corrects the alignment, and it is done gradually while the monitoring is watched closely.

6. 06

   Graft and closure

   The exposed bone surfaces are roughened and graft is laid along them to fuse. Final imaging confirms screw position and alignment. The muscle is repaired in layers over the construct.

Recovery & expectations

Hospital stay

2–4 days

Collar

Often for a period, per surgeon instruction

Neck soreness

Weeks; stiffness longer

Desk work

4–8 weeks

Physical work

3–6 months

Fusion maturation

6–12 months

Figures are general ranges from the surgical literature and cannot be guaranteed for any one person. Recovery varies with the number of levels fused, whether alignment was corrected, and general health. Smoking substantially reduces the chance the bone fuses. Always follow the instructions you are given after your own operation.

Related

Which approach does your neck need?

How many levels are compressed, what your curve is doing on a standing X-ray, and whether a previous fusion has united are what decide this. Bring any imaging and any operative reports from previous neck surgery.