Poor Fusion Rates Following Cervical Corpectomy Reconstructed With an Expandable Cage: Minimum 2-Year Radiographic and Clinical Outcomes

Abstract

BACKGROUND Expandable cages are often used to reconstruct cervical corpectomies but there are few long-term follow-up studies with large numbers. OBJECTIVE To analyze the clinical and radiographic results of cervical corpectomy reconstructed with expandable cages for degenerative stenosis. METHODS We performed a retrospective analysis of 78 patients with degenerative cervical stenosis treated with a corpectomy reconstructed with an expandable cage. We evaluated the clinical and radiographic outcomes, as well as complications of the procedure at a minimum 2-yr follow-up. RESULTS There was a decrease in the visual analog scale pain average from 75 mm to 8.5 mm (P = .02); a decrease in the Neck Disability Index average from 55% to 12% (P = .009); and improvement in the Japanese Orthopaedic Association average from 12 to 14 points (P = .01). There was a change in cervical lordosis (Cobb method) average from −9.3° to −15.1° (P = .002), without significant loss of lordosis (P = .63). The fusion rate, by criteria of the Cervical Spine Research Society (CSRS), was low: using dynamic X-rays – 50% (n = 39/78) and using computed tomography (CT) – 47.4% (n = 37/78). A total of 11 patients (14.1%) suffered complications. CONCLUSION To our knowledge, this is the largest series (78) with a minimum 2-yr follow-up in the literature and the first using the dynamic radiographic and CT criteria endorsed by the CSRS. Using these criteria, our fusion rates were much lower than all previous reports in the literature. Despite this, patient-reported outcomes were reasonable. There was a relatively low incidence of perioperative complications, most of which were likely not implant-specific and there was only 1 case of implant failure.

Evaluation of Radiological and Neurological Outcomes after Anterior Cervical Corpectomy with Fusion using Expandable Cage Alone and Expandable Cage with Anterior Cervical Plating

“…In our study, fusion rate in both study group was 85% (expandable cage alone—78.33% and with anterior cervical plate—95%), which is almost similar to the study done by Pojskic et al, Brenke et al, Art et al, Hassan Allouch et al, Cappelletto et al, Byvaltsev et al, and Tohamy et al 13 14 15 16 17 18 19 The placement of expandable cage is very smooth and avoids any major damage to the vertebral endplates. It is an instinctive thought that subsidence should be lower in the cervical spine because of less axial loading in contrast to the dorsal and lumbar spine.…”

“…One of the subsidence prevention features of expandable cage is limited footprint surface area which leads to less fusion due to inadequate graft-host bone contact and in turn increases the risk of implant failure as compare with other nonexpendable cage so anterior cervical plating is useful 21. Cage subsidence in our study was 15% (expandable cage alone-21.67% and with anterior cervical plate-5%), similar findings were also reported by Brenke et al (14%) and Tohamy et al (5.68-14.71%), while in a study done by Pojskic et al and Art et al cage subsidence was relatively higher (24.4% and 42.7%, respectively) [13][14][15][16][17][18][19]. Previous studies have reported that expandable cages allow for improvement in cervical lordosis but no large comparative studies done evaluating the effect on cervical lordosis 3.…”

“…21 Cage subsidence in our study was 15% (expandable cage alone—21.67% and with anterior cervical plate—5%), similar findings were also reported by Brenke et al (14%) and Tohamy et al (5.68–14.71%), while in a study done by Pojskic et al and Art et al cage subsidence was relatively higher (24.4% and 42.7%, respectively). 13 14 15 16 17 18 19 Previous studies have reported that expandable cages allow for improvement in cervical lordosis but no large comparative studies done evaluating the effect on cervical lordosis. 3 In our study, change in C2-C7 Cobb's angle ranges from 3.52° to 4.35° similar to the study done by Brenke et al (5°), Tohamy et al (4°), and Byvaltsev et al (5.8°), and more change as compared with studies done by Cappelletto et al (1.3°), and Pojskic et al (1.8°), and these changes are may be as it allows the expansion of the cage in-situ and optimal fitting into the corpectomy defect, leading to the correction of kyphosis/lordosis or change in C2-C7 Cobb's angle, restoration of vertebral height, and sagittal alignment in single stage.…”

Posterior Paramedian Approach—A Simple Technique to Obtain a Lateral Viewing Angle for Spinal Lesions

“…However, these approaches are more invasive and often associated with complications. For example, unilateral facet removal tends to cause postoperative instability 10 , and corpectomy in anterior approaches requires xation with cages and plates 14,15 . Also, their approach routes are often not familiar to ordinary spine surgeons.…”

Clinical Importance of Hounsfield Unit in Computed Tomography of Sub-Axial Cervical Vertebral Body.

“…As a result, screw pull-out or breakage may occur due to the change of the force applied to the screw, which accelerates the deterioration of the plate system instability and causes an instrument failure or telescoping in which the entire surgical segment is collapsed [10,28]. In rare cases of catastrophic instrument failure may require reoperation in long-term non-union [29,30].…”