Abstract
Introduction This is a prospective, consecutive series of 178 prosthetic implantations to analyse single level versus multiple level cervical arthroplasty with two years minimum follow-up
Methods Fifty-five patients underwent a total of fifty-five Porous Coated Motion (PCM) cervical arthroplasties from C3–4 to C7–T1 (Group S for single level). Fifty-four patients underwent one hundred and nine multilevel PCM cervical arthroplasties (Group M for multilevel) during the same time interval, for the same indications, performed by the same surgeons under the same clinical protocol— double level, 43 cases; three levels, 7 cases: and four levels, 4 cases. Sixteen PCM cases had been performed as complex revision procedures with prior fusions—9 in Group S and 7 in Group M. They included 1 previous Bryan Disc, 1 cage-plate, 1 patient with Klippel-Feil disease, 3 patients had failed lordotic cervical cages. One additional patient in Group M had a fracture-dislocation at C4–5 with a pseudarthrosis at C3–4 and C5–6. The demographics between Group S and Group M were very similar—mean age of patients, gender, severity of neurologic symptoms and distribution of radicular and myeloradicular symptoms.
Results There were no deaths, no infections, and no instances of iatrogenic neurologic progression in either the single level or the multiple level arthroplasty group. The mean EBL, length of surgery, and length of hospital stay were greater for the Multilevel Group. In contrast to these three operative demographic statistics, the self assessment outcomes instruments consistently showed more improvement for the multilevel cases. The mean improvement in the NDI for the single cases was 54.8 % (+/− 20.9) versus the multilevel cases mean improvement in NDI was 64.8 % (+/− 33.7). The mean improvement in the VAS showed the same relationship—single level mean improvement 62.0 % (26.9) versus the multilevel cases mean VAS improvement was 68.1% (+/− 31.4). The SF-36, Odoms, and TIGT were also more improved for the multilevel versus the single level group. The reoperation rates, adverse events, and incidence of complications were the same between the single level to the multilevel arthroplasty groups.
Discussion This prospective report of cervical arthroplasty demonstrates that each cervical vertebral level is biomechanically independent of the adjacent level, whether it contains an arthoplasty or an unoperated intervertebral disc. With the Porous Coated Motion cervical arthroplasty the incidence of reoperation did not increase proportionately higher as the number of cervical levels requiring instrumentation increased. Even in three and four level arthroplasty the true benefits of cervical disk replacement outcomes were demonstrated on functional clinical outcomes at minimum two-year follow-up
The abstracts were prepared by Assoc Prof Bruce McPhee. Correspondence should be addressed to him at the Division of Orthopaedics, The University of Queensland, Clinical Sciences Building, Royal Brisbane Hospital, Herston, Brisbane, 4029, Australia.
