429 - Radiological Signs of Adjacent Segment Degeneration in Patients with C...

General Session: Innovative Technologies

Presented by: K. Siemionow - View Audio/Video Presentation (Members Only)

Author(s):

K. Siemionow(1), P. Janusz(1,2), J. Bou Monsef(1)

(1) University of Illinois at Chicago, Department of Orthopaedic Surgery, Chicago, IL, United States
(2) University of Medical Sciences, Department of Spine Disorders and Pediatric Orthopedics, Poznan, Poland

Abstract

Background: Cervical foraminal stenosis with radiculopathy commonly develops as a result of intervertebral disc degeneration or spondyloarthrosis. In select patients, cervical foraminal stenosis may be treated by indirect posterior cervical nerve root decompression and fusion using cervical cages placed bilaterally in the facet joints. Segmental fusion may have influence on adjacent segments. The aim of this study was to assess radiological signs of adjacent segment degeneration in patients with 2 year follow-up.

Methods: Study enrollment included fifty-one patients with a mean age of 53 years who underwent posterior fusion via bilateral placement of cervical cages for cervical spondylotic radiculopathy. All patients were part of a prospective, multi-center study. The lateral cervical X-rays were taken in neutral position pre-operatively at 1 and 2 years postoperatively. Adjacent level evaluation measures included: 1) Disc height ratio (DHR) - ratio of the disc height and the lower vertebrae height measured at level above and below; 2) Proximal junctional kyphosis (PJK); 3) Kellgren and Lawrence Osteoarthritis Severity Grade (KLOSG); 4) Heterotopic Ossification (HO). The results were compared with a repeated ANOVA test and Bonferroni correction; p< 0.05 was considered significant.

Results: There were no revision surgeries at the operated level or adjacent level at 2 year follow-up. There were 102 segments evaluated. Of those 21 upper and 21 lower segments showed clear ASDegen prior to surgery. Just 19 patients were free from any signs of degeneration at both adjacent levels. At 3 levels new mild ASDegen signs developed, 1 in level above and 2 in level below operated segment after 2 years. In patients with pre-existing disc degeneration mild progression of ASDegen signs developed in 6 upper and in 2 lower segments. There were no significant changes in DHR and in PJK in all patients, however, when patients with signs of ASDegen only were evaluated significant decrease of DHR was found. The mean DHR before surgery, 1 and 2 years after surgery in all patients was 44.0±8.1, 44.0±8.2 and 43.1±8.4; p=0.1006 and in ASD patients 43.8±7.3, 41.9±6.3 and 39.6±8.3; p=0.0062, respectively. Overall, at 2 years postoperative, ASDegen was identified in nine patients (17.6% when compared to all evaluated patients before surgery).

Conclusions: In patients treated with cervical cages placed in facet joints via a posterior approach, mild progression of ASDegen can be expected in a small subset of patients. Cervical fusion with cervical cage placement does not induce rapid progression of ASDegen. Further evaluation to establish long-term incidence of ASDegen is needed.

Figure 1. Subsequent radiographs of the patient wi