Anterior Cervical Foraminotomy: 2-Dimensional Operative Video

Preoperative Radiographic Simulation for Partial Uncinate Process Resection during Anterior Cervical Discectomy and Fusion to Achieve Adequate Foraminal Decompression and Prevention of Vertebral Artery Injury

STUDY DESIGN

Retrospective radiographic study.

PURPOSE

This study aims to demonstrate the proper resection trajectory of a partial posterior uncinate process resection combined with anterior cervical discectomy and fusion (ACDF) and evaluate whether foraminal stenosis or uncinate process degeneration increases the risk of vertebral artery (VA) injury.

OVERVIEW OF LITERATURE

Appropriate resection trajectory that could result in sufficient decompression and avoid vertebral artery injury is yet unknown.

METHODS

We retrospectively reviewed patients who underwent cervical magnetic resonance imaging and computed tomography angiography for preoperative ACDF evaluation. The segments were classified according to the presence of foraminal stenosis. The height, thickness, anteroposterior length, horizontal distance from the uncinate process to the VA, and vertical distance from the uncinate process baseline to the VA of the uncinate process were measured. The distance between the uncinate anterior margin and the resection trajectory (UAM-to-RT) was measured.

RESULTS

There were no VA injuries or root injuries among the 101 patients who underwent ACDF (163 segments, mean age of 56.3±12.2). Uncinate anteroposterior length was considerably longer in foramens with foraminal stenosis, whereas uncinate process height, thickness, and distance between the uncinate process and VA were not significantly associated with foraminal stenosis. There were no significant differences in radiographic parameters based on uncinate degeneration. The UAM-to-RT distances for adequate decompression were 1.6±1.4 mm (range, 0-4.8 mm), 3.4±1.7 mm (range, 0-7.1 mm), 4.0±1.7 mm (range, 0-9.0 mm), and 4.5±1.2 mm (range, 2.5-7.5 mm) for C3-C4, C4-C5, C5-C6, and C6-C7, respectively.

CONCLUSIONS

More than half of the uncinate process in the anteroposterior plane should be removed for adequate neural foramen decompression. Foraminal stenosis or uncinate degeneration did not alter the relative anatomy of the uncinate process and the VA and did not impact VA injury risk.

Safety and Efficacy of Anterior Cervical Discectomy and Fusion with Uncinate Process Resection: A Systematic Review and Meta-Analysis

STUDY DESIGN

This is a meta-analysis and systematic review of the available literature.

OBJECTIVE

In the case of severe foraminal stenosis, conducting uncinate process resection (UPR) during ACDF could achieve complete nerve root decompression and significant relief of neurological symptoms for CR. However, there is some controversy regarding its necessity and safety. This study aims to compare the safety and efficacy of ACDF with UPR and ACDF.

METHODS

The following electronic databases were searched: Medline, PubMed, Embase, the Cochrane Central Register of Controlled Trials, Evidence Based Medicine Reviews, VIP, and CNKI. And the following data items were considered: baseline demographics, efficacy evaluation indicators, radiographic outcome, and surgical details.

RESULTS

10 studies were finally identified, including 746 patients who underwent ACDF with UPR compared to 729 patients who underwent ACDF. The group of ACDF with UPR had statistically longer intraoperative time (95% CI: 4.83, 19.77, P = .001) and more intraoperative blood loss (95% CI: 12.23, 17.76, P < .001). ACDF with UPR obtained a significantly better improvement of Arm VAS at postoperative first follow-up (95% CI: -1.85, -.14 P = .02). There was no significant difference found in improvement of Neck VAS at postoperative latest follow-up (95% CI: -.88, .27, P = .30), improvement of Arm VAS at postoperative latest follow-up (95% CI: -.59, -.01, P = .05), improvement of NDI (95% CI: -2.34, .33, P = .14), JOA (95% CI: -.24, .43, P = .56), change of C2-C7 lordosis (95% CI: -.87, 1.33, P = .68), C2-C7 SVA (95% CI: -.73, 5.08, P = .14), T1 slope (95% CI: -2.25, 1.51, P = .70), and fusion rate (95% CI: .83, 1.90 P = .29).

CONCLUSION

ACDF with UPR is an effective and necessary surgical method for CR patients with severe foraminal stenosis.

Microanatomical considerations for safe uncinate removal during anterior cervical discectomy and fusion: 10-year experience

Cervical radiculopathy from uncovertebral joint (UVJ) hypertrophy and nerve root compression often occurs anterior and lateral within the cervical intervertebral foramen, presenting a challenge for complete decompression through anterior cervical approaches owing to the intimate association with the vertebral artery and associated venous plexus. Complete uncinatectomy during anterior cervical discectomy and fusion (ACDF) is a controversial topic, many surgeons relying on indirect nerve root decompression from restoration of disc space height. However, in cases of severe UVJ hypertrophy, indirect decompression does not adequately address the underlying pathophysiology of anterolateral foraminal stenosis. Previous reports in the literature have described techniques involving extensive dissection of the cervical transverse process and lateral uncinate process (UP) in order to identify the vertebral artery for safe removal of the UP. Recent anatomical investigations have detailed the microanatomical organization of the fibroligamentous complex surrounding the UP and neurovascular structures. The use of the natural planes formed from the encapsulation of these connective tissue layers provides a safe passage for lateral UP dissection during anterior cervical approaches. This can be performed from within the disc space during ACDF to avoid extensive lateral dissection. In this article, we present our 10-year experience using an anatomy-based microsurgical technique for safe and complete removal of the UP during ACDF for cervical radiculopathy caused by UVJ hypertrophy.

How I do it: total uncinatectomy during anterior diskectomy and fusion for cervical radiculopathy caused by uncovertebral joint hypertrophy

BACKGROUND

Cervical radiculopathy from uncovertebral joint hypertrophy and foraminal stenosis is a common indication for anterior cervical diskectomy and fusion (ACDF). Often, the uncinate hypertrophy extends lateral to the foramen and impinges on the nerve close to the vertebral artery as it travels in between the transverse foramina.

METHOD

Using an injected cadaveric specimen to highlight the vital neurovascular and bony structures pertinent to this procedure, we demonstrate the technical details of complete uncinatectomy for cervical foraminal stenosis.

CONCLUSION

Total uncinatectomy is a useful adjunct during ACDF for complete foraminal decompression in cases of uncovertebral joint hypertrophy.

Anterior Techniques in Managing Cervical Disc Disease

Surgical treatment may be indicated for select patients with cervical disc disease, whether it is cervical disc herniation or spondylosis due to degenerative changes, acute cervical injury due to trauma, or other underlying cervical pathology. Currently, there are various surgical techniques, including anterior, posterior, or combined approaches, in addition to new interventions being utilized in practice. Ideally, the surgical approach should be selected in consideration of each patient’s clinical presentation, imaging findings, and overall medical comorbidities on an individual basis. But the unique advantages and disadvantages of each surgical technique often complicate the therapy choice in managing cervical disc diseases. Although anterior cervical discectomy and fusion (ACDF) is the most widely accepted procedure performed for both single and multi-level cervical disc diseases, there are multiple modifications to this technique. Surgeons have access to different types of plates, screws, and cages and can adopt newer advances in the field such as stand-alone and minimally invasive techniques when indicated. In short, no consensus exists in terms of a single approach that is preferred for all patients. This article aims to review the standard of care for management of cervical disc disease with a focus on the surgical techniques and, in particular, the anterior approach, exploring the various surgical options within this technique.