4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

Abstract

In the future, there will be an increased number of cervical revision surgeries, including 4-and more-levels. But, there is a paucity of literature concerning the geometrical and clinical outcome in these challenging reconstructions. To contribute to current knowledge, we want to share our experience with 4-and 5-level anterior cervical fusions in 26 cases in sight of a critical review of literature. At index procedure, almost 50% of our patients had previous cervical surgeries performed. Besides failed prior surgeries, indications included degenerative multilevel instability and spondylotic myelopathy with cervical kyphosis. An average of 4.1 levels was instrumented and fused using constrained (26.9%) and non-constrained (73.1%) screw-plate systems. At all, four patients had 3-level corpectomies, and three had additional posterior stabilization and fusion. Mean age of patients at index procedure was 54 years with a mean follow-up intervall of 30.9 months. Preoperative lordosis C2-7 was 6.5°in average, which measured a mean of 15.6°at last follow-up. Postoperative lordosis at fusion block was 14.4°in average, and 13.6°at last follow-up. In 34.6% of patients some kind of postoperative change in construct geometry was observed, but without any catastrophic construct failure. There were two delayed unions, but finally union rate was 100% without any need for the Halo device. Eleven patients (42.3%) showed an excellent outcome, twelve good (46.2%), one fair (3.8%), and two poor (7.7%). The study demonstrated that anterior-only instrumentations following segmental decompressions or use of the hybrid technique with discontinuous corpectomies can avoid the need for posterior supplemental surgery in 4-and 5-level surgeries. However, also the review of literature shows that decreased construct rigidity following more than 2-level corpectomies can demand 360°instrumentation and fusion. Concerning construct rigidity and radiolographic course, constrained plates did better than non-constrained ones. The discussion of our results are accompanied by a detailed review of literature, shedding light on the biomechanical challenges in multilevel cervical procedures and suggests conclusions.

The stabilizing potential of anterior, posterior and combined techniques for the reconstruction of a 2-level cervical corpectomy model: biomechanical study and first results of ATPS prototyping

“…Segmental anterior fixation using a constrained plate was also shown comparable to CPS stabilization in a 2-level injury model [8]. Hence, authors recommended segmental fixation which is in line with clinical rationales [8,31]. But in selected cases corpectomies at multiple levels are indicated, and in our 2-level corpectomy model the 360°c onstruct outperformed all others, the least concerning its median ROM values (Figs.…”

“…Accordingly, reconstructions of most cervical disorders do not require CPS. But, of the current techniques, transpedicular anchorage provides highest stability [2,3,22,31,38,44,62], and in selected patients with advanced instability, CPS fixation is a sound treatment [12,21,28,62] with high accuracy rates in the hands of trained surgeons, particularly at C2 and C7 [1,9,25,29,62]. Our study offers new biomechanical data for the selective usage of CPS.…”

“…Multilevel cervical constructs generate a large lever-arm at their end-level anchors that can cause construct failure before fusion matures [31,41]. Several reviews of literature documented the challenge with anterior multilevel fusions [3,10,31,32].…”

“…Several reviews of literature documented the challenge with anterior multilevel fusions [3,10,31,32]. Reports of failure with anterior-only instrumentation of 2-and even 1-level corpectomies continue.…”

“…With the number of decompressed levels, particularly corpectomies performed, the intrinsic stability of the spine drops, which is a challenge to current anterior instrumentations [10]. Likewise, two reviews of literature identified a high rate of complications in reconstructive multilevel ([2 levels) cervical spine surgery, particularly if decompression required multiple corpectomies and a posterior supplemental instrumentation was not performed [3,31]. Accordingly, for a successful outcome with C2-level corpectomies, a combined anterior and posterior approach was found a sound rationale [32] but necessitating a second posterior approach with significant morbidity.…”