Posterior cervical foraminotomy, with or without diskectomy, is a well described and minimally incisional procedure that is effective for the treatment of cervical radiculopathy owing to foraminal stenosis or a lateral disk herniation. The procedure does not require a concomitant fusion; does not significantly destabilize the spine; and does not expose the trachea, esophagus, recurrent laryngeal nerve, or vertebral artery to potential injury. The procedure is generally performed as an outpatient procedure, and operative morbidity is quite low.
13.2 Patient Selection
The posterior cervical foraminotomy is appropriate for patients with cervical radiculopathy caused by foraminal stenosis or a lateral disk herniation ( ▶ Fig. 13.1). Paracentral or midline pathology is not well addressed with this approach. Although the approach may be modified (through undercutting of the spinous process) to treat myelopathy, these techniques are discussed elsewhere in the text and not addressed herein.
Fig. 13.1 Diagram of an axial section at the level of a cervical intervertebral disk. The posterolateral route is appropriate only for posterolateral pathology, such as the lateral disk herniation here illustrated.
13.3 Preoperative Preparation
After the induction of adequate general anesthesia and the placement of routine venous access lines and compression hose, the patient is placed in the seated position. Although ultrasonic monitoring for air embolism may be performed, the incidence of air embolism with this procedure is extremely low. For this reason, placement of central lines (placed to aspirate air from the atrium or vena cava) is probably associated with greater morbidity than benefit. A lateral fluoroscope is positioned under the drapes to allow visualization of the position of the retractors and instruments during the procedure. I use a microscope to perform the procedure; however, endoscopic approaches have been well described and are applicable as well.
13.4 Operative Procedure
The seated position ( ▶ Fig. 13.2) allows for greater radiographic visualization of the lower cervical spine and is associated with substantially less bleeding than the Concorde position with the patient prone and the neck flexed. Once the patient is prepared and draped, a spinal needle or other radiopaque tool is used to mark the incision site. The incision is centered just rostral to the level of intended decompression ( ▶ Fig. 13.3). This rostral-to-caudal angle of approach makes it much easier for the surgeon using a microscope. The incision is made approximately 2 cm lateral to midline. The incision necessary for adequate exposure depends on the retractor system used. With a small-bladed retractor system or a table-mounted tubular-retractor system, only a small (1.5 to 2 cm) incision is necessary. Electrocautery is used to carry the incision through the posterior fascia. If a bladed retractor is used, blunt finger dissection to the level of the lamina may be used to complete the exposure. If a tubular retractor system is used (which I prefer), the smallest tubular retractor is positioned under fluoroscopic guidance such that it rests on the posterior aspect of the inferior articulating facet of the rostral vertebral body. It is critical to perform this step under fluoroscopic guidance and to make absolutely sure that the tip of the retractor engages bone. I generally do not use a K-wire for cervical procedures because interlaminar placement is possible if the K-wire is placed too medially. Continued advancement in this situation could have catastrophic results. Once the initial retractor is positioned, serial dilators are used to complete the dissection ( ▶ Fig. 13.4). Once the dilation is complete, the table-mounted tubular retractor is positioned and a final radiographic check of the position is performed. I have found the table-mounted retractor to be more convenient for this procedure because of the ability to fix the retractor to the table and because of the absence of a fixed handle, which can interfere with the ideal placement of the retractor.
Fig. 13.2 The patient is placed in the seated position. It is important to have the neck perpendicular to the floor and to position the fluoroscopy unit before draping to ensure that adequate visualization is possible, especially of the lower cervical spine. The midline has been marked, as has a line at the appropriate rostral–caudal level for incision.
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