Posterior Cervical Foraminotomy

Kern Singh, MD

Steven J. Fineberg, MD

Matthew Oglesby, BA

Jonathan A. Hoskins, MD

Vamshi Yelavarthi, BA

Dr. Singh or an immediate family member has received royalties from Pioneer and Zimmer and serves as a paid consultant to or is an employee of DePuy, Stryker, and Zimmer. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Fineberg, Mr. Oglesby, Dr. Hoskins, and Mr. Yelavarthi.

INTRODUCTION

Decompressive procedures employed in the management of cervical radiculopathy have evolved in recent years. New advancements, such as the integration of minimally invasive techniques, offer an alternative to traditional open techniques. The concept behind minimally invasive techniques is to achieve symptom relief with the reduction in morbidity that is associated with traditional techniques. The posterior cervical foraminotomy can be executed using a minimally invasive approach to treat cervical radiculopathy. A prior study suggests that results from the procedure are comparable to that of a conventional open foraminotomy.¹

Posterior cervical foraminotomy eliminates the risk of injuring structures in the anterior approach (ie, carotid artery, esophagus, recurrent laryngeal nerve).² In addition, the procedure does not require a fusion, does not destabilize the disk space, and is an easy approach to directly decompress the foramen. An important limitation compared with the anterior approach is the inability to deal directly with pathology affecting the central aspect of the canal. Posterior procedures require more dissection of the large extensor spine muscle mass with a possible increase in postoperative neck pain.

The approach may be modified by undercutting of the spinous process to treat myelopathy; however, the relative efficacy and safety have not been demonstrated.³

PATIENT SELECTION

Indications

Cervical radiculopathy is frequently a result of an osteophyte, spondylosis, and/or lateral disk herniation compressing a nerve root in the neural foramen. Posterior cervical foraminotomy is appropriate for patients with persistent radiculopathy that correlates with findings on CT, MRI, and/or myelography and in whom nonsurgical management has failed. Patients with refractory radiculopathy after anterior cervical diskectomy and fusion are also indicated for posterior cervical foraminotomy.

Contraindications

The spine surgeon must recognize the contraindications to performing posterior cervical foraminotomy. In the initial consultation, a thorough history and physical examination should be conducted, noting any signs or symptoms of a local skin infection, cervical myelopathy, significant kyphosis, or mechanical instability of the cervical spine. Evidence of spinal cord compression, significant disk herniation compressing the nerve root, and symptomatology not referable to the pathology visualized on imaging studies are contraindications to performing the procedure.

PREOPERATIVE IMAGING

Routine preoperative imaging should consist of AP and lateral radiographs to assess cervical alignment. Dynamic flexion and extension views are also helpful to identify any instability that requires a fusion. MRI should also be obtained to evaluate the spinal cord and nerve roots for sites of compression (Figures 1 and 2). If MRI cannot be obtained, a CT myelogram may be performed instead.

FIGURE 1 T2-weighted axial MRI shows a disk herniation (arrow) in the C5-6 neural foramen compressing the left C5-6 nerve root (arrowhead).

FIGURE 2 T2-weighted axial MRI shows severe compression of the left C5-6 nerve root (arrow) in the C5-6 neural foramen.

PROCEDURE

Room Setup/Patient Positioning

The procedure can be performed with the patient in the prone or seated position. After induction of general anesthesia, a three-pin Mayfield fixation is applied, fixing the head to the table in the prone position. A Wilson frame or similar bolsters are placed under the torso.

All possible neural compression points should be carefully protected and padded. The neck is extended, with care taken to avoid hyperextension. The chin is slightly tucked in a “military” posture that aids in the approach. Extreme flexion or extension of the neck should be avoided to prevent positioning the neck in a nonanatomic position. A reverse Trendelenburg position allows venous drainage and less bleeding during surgery.

A fluoroscopic C-arm is positioned under the drapes to allow visualization of the position of the retractors during the procedure. The shoulders should be taped down to allow better radiographic visualization of the neck. The knees are flexed to prevent distal migration of the patient.

VIDEO 100.1 Open Cervical Foraminotomy. Kern Singh, MD; Steven J. Fineberg, MD; Matthew Oglesby, BA; Jonathan A. Hoskins, MD; Vamshi Yelavarthi, BA (3 min)

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