Article

Sagittal cervical alignment after cervical disc arthroplasty and anterior cervical discectomy and fusion: results of a prospective, randomized, controlled trial.

Department of Orthopaedic Surgery, The University of Pennsylvania, Philadelphia, USA.
Spine (Impact Factor: 2.45). 09/2009; 34(19):2001-7. DOI: 10.1097/BRS.0b013e3181b03fe6
Source: PubMed

ABSTRACT Radiographic results of a multicenter, prospective randomized study comparing 1-level cervical total disc replacement (TDR-C) with anterior cervical discectomy and fusion (ACDF).
To evaluate the effect on device-level lordosis, cranial and caudal adjacent level lordosis, and overall cervical sagittal alignment (C2-C6) after TDR-C or ACDF.
Cervical total disc replacement (TDR-C) has emerged as a promising alternative to ACDF in a select group of patients. The maintenance and/or improvement of sagittal balance is essential in preserving functionality after reconstructive spinal procedures. Recent studies have documented changes in spinal alignment after TDR-C, however, no studies have compared these changes to those noted in matched group of patients that have undergone ACDF.
Radiographic data were obtained from the randomized group of a multicenter, randomized, prospective, controlled study comparing TDR-C (ProDisc-C, Synthes Spine, West Chester, PA) with ACDF in the treatment of 1-level cervical disc disease. Complete radiographic data were available for 89 TDR-C patients (average age: 42.2 years) and 91 ACDF patients (average age: 41.7 years). Cervical lordosis at the device level, cranial and caudal adjacent levels, and total cervical lordosis (C2-C6) were independently measured before surgery and 2 years after surgery using custom image stabilization software (Quantitative Motion Analysis, Medical Metrics, Inc, Houston, TX).
C5-C6 was the most common operative level (TDR-C: 54%; ACDF: 55%). At 2 years after surgery, the TDR-C group experienced statistically significant changes in lordosis of 3.0 degrees (P < 0.001), 0.90 degrees (P = 0.006), and -1.9 degrees (P < 0.001) at the operative, cranial, and caudal adj-acent levels, respectively. ACDF experienced changes in lordosis of 4.2 degrees (P < 0.001), 1.0 degrees (P = 0.001), and -1.5 degrees (P = 0.001), respectively. The between-group differences were significant at the operative level (P = 0.03) and the caudal adjacent level (P = 0.05). Total cervical lordosis increased in both TDR-C and ACDF by 3.1 degrees and 3.8 degrees , respectively (P = 0.49).
In both TDR-C and ACDF, lordosis increased at the device-level, cranial adjacent level, and in total cervical lordosis, while lordosis decreased at the caudal adjacent level. Although ACDF facilitated a greater increase in device level lordosis (+1.25 degrees ) and less loss of lordosis at the caudal adjacent level compared with TDR-C (-0.39 degrees ), the clinical relevance of the small differences remain unknown.

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    ABSTRACT: Park MS, Kelly MP, Lee D-H, et al. Sagittal alignment as a predictor of clinical adjacent segment pathology requiring surgery after anterior cervical arthrodesis. Spine J 2014;14:1228-34 (in this issue).
    The spine journal: official journal of the North American Spine Society 07/2014; 14(7):1235-6. DOI:10.1016/j.spinee.2014.05.007 · 2.80 Impact Factor
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    ABSTRACT: Study background: Heterotopic ossification (HO) is a well-known complication of cervical total disc replacement (CTDR), a successful alternative to cervical decompression and fusion for degenerative disc disease. Objective: The aim of our study was to evaluate the incidence of HO in single and double-level Discover disc replacement, a relatively new type of artificial implants. Moreover, the related clinical and radiological outcomes and the possible influencing factors were analysed. Methods: Twenty-six women and 39 men were retrospectively followed-up for 5 years. They consecutively underwent one or two-level cervical Discover arthroplasty. Clinical outcome was assessed using the visual analogue scale (VAS). The angular range of motion (ROM) was calculated with periodic dynamic X-rays. A Student's t test was used to analyse the association between the occurrence of HO and various risk factors. Results: Among the 65 patients enrolled, the overall incidence of HO was 7.69% and the mean follow-up was 63.29 ± 11.90 months. All the cases were diagnosed as Grade III or Grade IV. The mean VAS showed immediate postoperative improvements and the mean ROM was partially maintained. No displacement of the prostheses was detected. Conclusions: During the 5-year follow-up period, the Discover cervical discs have provided optimal clinical outcomes showing a lower and tardive incidence of HO than other reported implants. Although a longer follow-up with a larger group of patients should be investigated, cervical arthroplasty can be still considered a safe and effective procedure in highly selected patients. Copyright: © 2014 Maida G, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.