Cervical Spine Surgery in Disc Disease

Cervical spine surgery for is most commonly performed for radiculopathy and cervical degenerative disc disease. The goal of cervical spine surgery is similar of lumbar spine surgery – adequate decompression of the nerve roots and stabilization of the spine

• Anterior cervical discectomy
• Anterior cervical discectomy  and fusion
• Anterior cervical discectomy  and fusion with internal fixation
• Posterior Foraminotomy
• Laminectomy with or without fusion
• Laminoplasty

The choice of the appropriate procedure depends on

• Location of the compression
• Presence of deformity or instability
• Number of levels involved
• Patient age and surgical fitness levels

Approach for Cervical Spine Surgery

In general anterior pathology, such as a centrally herniated disk and anterior osteophytes, is treated anteriorly, and posterior pathology, such as posterolateral osteophytes/disc herniations, may be treated with a posterior approach.

Both anterior and posterior approaches are found to be equally effective.

Anterior Cervical Discectomy

Anterior cervical discectomy procedure performs a decompression of the nerve roots by disc removal using an anterior approach. It may or may not be associated with fusion of the involved vertebrae depending on surgeon preference. Most surgeons now routinely use fusion.

The procedure is chosen for patients  with normal cervical lordosis, minimal axial pain, and abnormalities limited to one level.

Possible risks and complications of anterior cervical discectomy are

• Nerve root damage
• Damage to spinal cord [1 per 10,000]
• Bleeding
• Infection
• Graft dislodgment
• Trachea or esophagus injury
• Persistent pain
• Recurrent laryngeal nerve injury causing hoarseness

Anterior Cervical Discectomy and Fusion

An interbody vertebral fusion along with cervical discectomy avoids recurrent radicular pain following foraminal narrowing and the risk of developing late kyphosis from disk-space collapse.

Therefore most of the surgeons perform fusion along with removal of cervical disc.

The fusion becomes more desirable in case of multiple level involvement and cervical spine instability.

Usually, for single level fusion, autologous bone graft is used.  To avoid graft donor site morbidity, alternatives to bone grafts like  allograft bank bone, bovine cancellous bone, and synthetic graft materials.

Failure to fuse is a risk with fusion surgery. Up to 95% union rate has been reported with autologous bone grafts.

Allografts have been shown to provide similar results when used in the anterior cervical spine.

When not fixed,  there is  the 1-2%  risk of graft dislodgment or extrusion.  Another surgery may be required for  reinsertion of the  bone graft, and instrumentation .

Anterior Cervical Discectomy, Fusion and Internal Fixation

This cervical spine surgery is indicated in patients

• Who require the procedure at multiple levels
• Have documented instability
• Who smoke [increases risk of non union]
• Patients with a prior history of nonunion
• Previous fusion adjacent to the level to be fused
• Graft dislodgement

Plating provides sound fixation and in postoperative period, no brace is required. It allows an earlier return to work and resumption of daily activities. Therefore many surgeons prefer plating at single level disease also.

Posterior Cervical Foraminotomy

This procedure can be done for nerve root decompression. It uses a posterior approach and is  most commonly in soft posterolateral disc herniations. This procedure obviates the need for a fusion. High success rates have been reported.

Cervical Corpectomy with Fusion

A corpectomy means the removal of a vertebral body and the disc spaces at either side to completely decompress the cervical canal.

The surgery is indicated in  multiple areas of spondylotic compression of the spinal cord.

Strut grafting is needed with multilevel corpectomy to prevent kyphotic deformity and to restore stability. Anterior plating is recommended for corpectomy and multilevel procedures to reduce the risk of graft extrusion and pseudoarthrosis.

It must be noted the as the length of the fusion increases, the rates of both graft and instrumentation-related complications increase. So posterior stabilization is recommended to improve stability and fusion rates and reduce graft and instrumentation-related complications.

Corpectomy is a more extensive procedure than a discectomy and thought the complication profile is similar to anterior cervical discectomy, risks are greater.

To monitor and decrease risk of spinal cord injury, spinal cord function can be monitored during surgery using somatosensory evoked potentials.

Another risk is compromising the vertebral artery, which can cause a stroke.

Cervical Laminectomy with or without Fusion

Laminectomy means removal of lamina. Cervical laminectomy is needed in cases of congenital cervical stenosis or if the disease process involves more than 3 levels or multiple discontinuous levels. If most of the compression of the spinal cord is posterior, laminectomy can sometimes be used.

The main risk with cervical posterior laminectomy is deterioration in neurological function after surgery. Use of intraoperative somatosensory evoked potentials can decrease this risk. Dural tear, infection, bleeding, increased pain, and instability in the spinal column are other risks.

If a laminectomy is performed, a fusion is recommended to prevent kyphotic progression.

Posterior fusion  is indicated in  evidence of instability, failure of anterior fusion, or decompression involving bilateral facetectomy.

Cervical Laminoplasty

The laminoplasty technique involves osteoplastic enlargement of the spinal canal by performing the laminectomy on one side  and then widening the canal by opening the lamina like a door hinging on the intact side.

This procedure is not associated with instability that us associated with laminectomy.

It is used in cervical myelopathy and advanced cervical spondylosis.

Cervical keyhole Foraminotomy

Posterolateral keyhole foraminotomy is indicated for posterolateral disc herniations with radicular pain. It is an efficient way of decompressing a lateral soft disk without the risks of an anterior approach. A bone graft is not needed in this cervical spine surgery. Use of an operative microscope helps achieve good outcomes.

Dynamic Cervical Implant Arthroplasty

The dynamic cervical implant arthroplasty is a relatively new device that is used to achieve anterior decompression without cervical fusion. In addition, the device results in some limitation of rotation and translation thereby preventing further degeneration of the small joints.

Some studies have shown dynamic cervical implant arthroplasty to provide better overall cervical range of motion and segmental range of motion  at the treated level as compared to anterior cervical decompression and fusion.