Anterior Cervical Discectomy
Patients are generally placed in a supine position with the head in an extended position. As noted above, Gardner-Wells tongs can be used for additional cervical traction. The hands can also be tied downward to increase the operative exposure. Once the surgical site is properly prepared with cleansing material, the appropriate surgical level is identified with intraoperative radiographs.
A scalpel is used to make a linear longitudinal incision just medial to the body of the sternocleidomastoid muscle. The incision is made long enough to include at least 2 vertebral levels if a 1-level discectomy is being performed. Alternatively, transverse skin incisions over the targeted vertebral level can also be performed. The platysmal muscle is identified and incised. The platysmal incision can be extended if a multilevel decompression is the surgical aim. Extensive subplatysmal dissection is performed to reduce retraction injury.
The esophagus is identified and retracted medially, while the sternocleidomastoid and underlying carotid sheath is retracted laterally. The prevertebral fascia is divided, and the longus colli musculature is further retracted. At this point, intraoperative radiographs should be obtained again to confirm the appropriate cervical level. Surgeons have recommended that electrocautery tools be avoided when operating below the C6 level to limit injury to the recurrent laryngeal nerve.
A self-retraction system can be used to maintain an open operative field. The retraction system should be released hourly to prevent ischemic injury. An operating microscope can also be used. The benefits of using an operative microscope include added magnification and focused lighting to improve visualization of the smaller and deeper surgical field. Moreover, the improved visualization may be advantageous in decompressing the nerve roots contralateral to the initial surgical approach.
Once properly visualized, the offending disc can be removed with a rongeur or drill set. As the posterior aspect of the vertebral body is reached, upward-curette tools can be used to maximize removal of osteophytes. The posterior longitudinal ligament should be visualized. Of note, if only an ACD procedure is being performed, the disc should not be entirely removed, and the cartilaginous endplates except for the posterior cortical margins should be left intact. If an ACDF or ACDFI is being performed, the entire disc should be removed and the vertebral body endplates must be decorticated with a drill. At this point, the ACD procedure is complete; the retractor system should be removed and closure of the surgical site can be initiated.
If an ACDF or ACDFI procedure is being performed, a bone graft must be placed in the open disc space. An applicator is often used to determine the graft size. The graft is then applied. If autograft is used, the fibula or iliac crest sites must be surgically prepared. The graft is then decorticated and processed for placement into the disc space. If plate instrumentation is to be used, the appropriate screw tools are used to properly screw the plates to the adjacent vertebral bodies. Lateral radiographs can be used to assess proper plate and screw placement intraoperatively.
At this point, the ACDF and ACDFI procedures are complete; the retractor system should be removed, and closure of the surgical site can be initiated. Postoperatively, a cervical collar can be worn for up to 6 weeks.
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(Left) MRI, Sagittal T2 sequence, demonstrating a central cervical disk herniation causing cervical myelopathy. (Center) MRI, Axial T2 sequence, demonstrating a normal cervical disk that does not cause compression of the spinal cord or the exiting nerve roots. (Right) MRI, T2 Sequence, Axial T2 sequence, demonstrating a central disk herniation causing compression and deformation of the spinal cord, causing symptoms of cervical myelopathy.
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MRI, Axial T2 sequence, demonstrating a right-sided cervical disk herniation causing cervical nerve root impingement and resulting radiculopathy.
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Upright lateral plain film following an anterior cervical diskectomy and fusion, demonstrating the bone graft between the vertebral bodies and the abutting cervical plate.
