Video-Assisted Anterior Cervical Diskectomy and Instrumentation

46 Video-Assisted Anterior Cervical Diskectomy and Instrumentation

Keith A. Kerr, Victor Lo, Ashley E. Brown, Alissa Redko, and Daniel H. Kim

46.1 Introduction

Anterior cervical diskectomy and fusion was first developed in the 1950s as a treatment for cervical disk disease.1 The advent of the operating microscope (OM) and microsurgical techniques improved the visualization, lighting, and ease of dissection of this approach and provided satisfactory results.² The endoscope has been used more and more frequently in neurosurgery for operations traditionally done with the OM, including spine surgery.^3,4,5 The senior author has applied this technology in anterior approaches to the cervical spine for a variety of pathologies.

The video telescope operating monitor (VITOM) has comparable capabilities to the OM with respect to focal length (25–75 cm compared to 20–40 cm) and magnification (both at 12x), while having the advantage of a larger depth of field (3.5–7.0 cm versus 1.2 cm). In addition, there are cost, ergonomic, and educational advantages provided by the system. The cost of the typical neurosurgical microscope is over $200,000, while the VITOM system costs less than $75,000.⁶ This makes it a more widely affordable technology. Ergonomically, the VITOM system is much smaller and attaches to the operating table, making it usable even in smaller operating rooms. Other ergonomic advantages include less frequent adjustments to the scope due to the larger depth of field and no need to adjust one’s posture to look into eyepieces. Since the OM is utilized only during the deepest portion of dissections, the field is viewable by others in the room for only a brief period of the operation. The VITOM can be used even in the more superficial portion of the dissection, making it a superior educational tool.

This chapter describes the use of the VITOM for anterior cervical diskectomy and instrumentation (Video 46.1).

46.2 Equipment Specific to This Approach

• Autoclavable rigid lens 0° telescope (VITOM SPINE HOPKINS; Karl Storz Endoscopy, Tutlingen, Germany)

• C-mount coupler (Stryker, San Jose, CA)

• 1280 × 1024 high-definition camera (1288 HD Video Camera; Stryker)

• Light-emitting diode (LED) system (L9000; Stryker)

• Two 26-inch, 1920 × 1080 resolution, 1 billion colors monitors (Vision Pro 26” LED; Stryker)

• Pneumatic endoscope holder (Point Setter, Mitaka Kohki, Tokyo, Japan)

• Optional archiving system (SDC3; Stryker) for documentation

46.3 Procedure

46.3.1 Operating Room Setup

• In addition to the typical operating room setup, a tower including a high-definition (HD) screen and a power source for the scope, camera, and Mitaka arm are placed opposite the surgeon. An additional HD screen is placed opposite the assistant (Fig. 46.1).

• The patient is placed in a supine position on a regular operating table with the head held in slight extension. The use of bolsters or a shoulder roll underneath the shoulder blades facilitates the position

• The incision is then marked from near the midline to the edge of the sternocleidomastoid at the appropriate level identified using either external landmarks or X-ray guidance. Using a skin crease or fold can provide a superior cosmetic result.

• The Mitaka Point Setter is attached to the side rail by the OR table adapter prior to sterile preparation and draping of the patient. The nitrogen source is then connected with the provided cables, and an operational and range-of-motion check is performed prior to draping (Fig. 46.2).

• In addition to the normal draping, prior to attachment of the VITOM, the Mitaka arm is draped with a sterile bag provided by the manufacturer, and is secured with adhesive tape.

• The endoscope and its attached camera are then attached to the arm by the endoscope holder and the illumination source’s fiberoptic cables are connected to its power source. The endoscope and arm can then be positioned out of the way of the surgeon during the superficial dissection (Fig. 46.3).

46.3.2 Superficial Dissection

• After an appropriate time out, an incision is made using a No. 10 blade down to the level of the fat overlying the platysma.

• Careful hemostasis is obtained, and a Weitlaner retractor is positioned over the platysma. The platysma is dissected in the orientation of the incision sharply or by monopolar cautery, and is undermined extensively both superiorly and inferiorly.

• The sternocleidomastoid and omohyoid muscles are then identified. The dissection proceeds between the muscles, with careful attention paid not to injure the trachea and esophagus medially, and the carotid sheath and its contents laterally. The omohyoid can be mobilized superiorly for access to the most caudal levels of the cervical spine.

46.3.3 Deep Dissection and Retractor Placement

• The prevertebral fascia and longus colli are encountered next, and a handheld retractor can be placed on top of the vertebral bodies and intervertebral disks to gently retract the esophagus and trachea to the contralateral side.

• The prevertebral fascia can then be bluntly dissected off the anterior portion of the vertebral bodies by a Kittner.

• After confirmation of the correct level by use of X-ray and a spinal needle, the longus colli can be dissected off the anterior vertebral body by monopolar cautery at the needed levels. This is performed to the medial uncovertebral joint, facilitating the formation of a lip of muscle that will hold the retractor system in place

Fig. 46.1 Operating room setup with monitors across from both the operator and the assistant. A tower containing the power source for the camera, Mitaka arm, and HD screens is positioned at the end of the bed on either side.