Anterior cervical discectomy and fusion (ACDF) has been performed with various techniques and devices for many years. Autologous iliac crest grafts were initially used for the Cloward1,2 and Robinson and Smith3 techniques, but because of iliac crest graft site complications (eg, pain, infection, fracture, dystrophic scarring4,5), the procedure was generally superseded by allograft implants. These implants were then supplemented with anterior locking plate devices. More recently, unitary devices combining a polyetheretherketone (PEEK) spacer with screw or blade fixation have been developed, such as the Zero P (Synthes, Inc.) and the ROI-C cervical cage (LDR). Bone graft is required to fill the cavity of these devices and to promote osseous union. Demineralized bone matrix,6 tricalcium phosphate,7,8 and bone morphogenetic protein (BMP) have been used for these purposes, but they add expense to the procedure and have been associated with several complications (eg, neck swelling, dysphagia associated with BMP).9
Although multiple studies have demonstrated effective fusion rates and good outcomes for both iliac crest autograft and grafting/spacer constructs, the debate over cost and “added value” remains unresolved. One institution, which has published articles reviewing the spine literature and its own data, concluded that iliac crest autograft was the most cost-effective and consistently successful ACDF procedure.5,10
The VA Portland Health Care System (VAPORHCS) has analyzed the use of local autograft sources at the surgical site to circumvent the need to make a second incision at the iliac crest and, theoretically, to decrease risks and expenses associated with iliac crest autograft, allograft bone, and artificial constructs. Given the paucity of data on this method, the case series presented here represents one of a few studies that analyze local autograft for promotion of arthrodesis in a PEEK spacer device.
This article will report on the prospectively collected results of consecutive cases performed by Dr. Ross using a ROI-C cervical cage for 1-level anterior cervical discectomy between August 2011 and November 2014. This study received institutional review board approval.
Methods
Neck disability index (NDI) forms were used to assess the impact of neck pain on patients’ ability to manage in everyday life. The NDI form was completed before surgery and 3 and 9 months after surgery.
Dr. Ross preferred to perform minimally invasive posterior cervical foraminotomy for unilateral radiculopathy. Therefore, all patients with radiculopathy had bilateral symptoms or a symptomatic midline disc protrusion not accessible from a posterior approach. Standard techniques were used to make a left-side approach to the anterior cervical spine except in cases in which a previous right-side approach could be reused. Under the microscope, the anterior longitudinal ligament and annulus were incised, and the anterior contents of the disc space were removed with curettes and pituitary rongeurs. Care was taken to remove all cartilage from beneath the anterior inferior lip of the rostral vertebral body and to remove a few millimeters of the anterior longitudinal ligament from the rostral vertebral body without use of monopolar cautery (Figure 1). A 2 mm Kerrison punch then was used to remove the anterior inferior lip of the rostral vertebral body, and this bone was saved for grafting. No bone wax was used within the disc space.
After all disc space cartilage was removed from the endplates, additional bone was obtained from the uncovertebral joints and posterior vertebral bodies as the decompression proceeded posteriorly. Occasionally, distraction posts were used if the disc space was too narrow for optimal visualization posteriorly. After decompression was achieved, a lordotic ROI-C cervical cage was packed in its lumen with the bone chips and impacted into the disc space under fluoroscopic guidance. The blades were impacted under fluoroscopic guidance as well. The wound was closed with absorbable suture.
Antibiotics were given for no more than 24 hours after surgery. Ketorolac was used for analgesia the night of the surgery, and patients were asked to not use nonsteroidal anti-inflammatory drugs for 3 months after surgery. Lateral radiographs were obtained 3 and 9 months after surgery and every 6 months thereafter until arthrodesis was detected.
Results
Seventy-seven consecutive patients underwent 1-level anterior cervical discectomy (Table 1). Twenty-four procedures were performed for radiculopathy, 52 for myelopathy, and 1 for central cord injury sustained in a fall by a patient with preexisting spinal stenosis. Surgery was performed at C3-C4 (25 cases), C4-C5 (11 cases), C5-C6 (15 cases), and C6-C7 (1 case) for patients with myelopathy. Surgery was performed at C3-C4 (2 cases), C4-C5 (3 cases), C5-C6 (9 cases), and C6-C7 (10 cases) for patients with radiculopathy.
