Objective: To analyze the incidence of heterotopic ossification after artificial cervical disc replacement with Discover disc, and to explore the effect of heterotopic ossification on postoperative radiological and clinical efficacy. Methods: From January 2010 to January 2015, 45 patients with cervical spondylosis underwent single-level artificial cervical disc replacement in Shanghai Changzheng Hospital, including 29 cases of cervical spondylotic myelopathy, 11 cases of cervical spondylotic radiculopathy and 5 cases of mixed cervical spondylosis. At the last follow-up, Mehren grading method was used for classification of heterotopic ossification, among which, grade 0-Ⅱ was defined as low grade ossification group, and 26 patients (16 male, 10 female) were enrolled in this group; grade Ⅲ-Ⅳ was defined as high grade ossification group, and 19 patients (12 males, 7 females) were included in this group. C(2-7) Cobb angle, cervical total range of motion and range of motion at index level were used to evaluate the radiological outcomes of the two groups. Japanese Orthopaedic Association (JOA) score, neck disability index (NDI) score and visual analogue scale (VAS) were used to evaluate the clinical outcomes of the two groups. The adjacent segment intervertebral disc height and range of motion were used to evaluate the effects of heterotopic ossification on adjacent segment. Results: All patients were followed up regularly for (98±18) months. There were no statistical differences between the two groups regarding to demographic data (all P>0.05). There was no significant differences in C(2-7) Cobb angle and total range of motion between the two groups at the last follow-up (all P>0.05), but range of motion at index level in the group with low grades was significantly higher than that in the group with high grades (7.8°±6.2° vs 2.6°±1.2°, t=3.60, P<0.05). There was no significant differences in JOA score, recovery rate and NDI score between the two groups (all P>0.05). There was no significant differences in the adjacent segment intervertebral disc height before operation and at the last follow-up (both P>0.05). There was no significant differences in range of motion at adjacent segment before operation (P>0.05), while range of motion at adjacent segment in the group with low grades was significantly lower than that in the group with high grades (9.5°±1.1° vs 10.6°±1.8° and 9.4°±1.4° vs 10.5°±1.7°, repectively, t=2.54, 2.31, both P<0.05). Conclusions: Heterotopic ossification does not affect the clinical outcomes, cervical curvature and cervical total range of motion after artificial cervical disc replacement with Discover disc. However, the higher grade of heterotopic ossification, the lower range of motion at index level and the higher range of motion at adjacent segment.
目的： 回顾性分析Discover颈椎人工间盘置换术后异位骨化（HO）发生情况，并探讨HO对患者术后影像学及临床疗效的影响。 方法： 收集2010年1月至2015年1月在上海长征医院因颈椎病行单节段Discover颈椎人工间盘置换术的45例患者，其中脊髓型颈椎病29例，神经根型颈椎病11例，混合型颈椎病5例。末次随访时HO采用Mehren分级法，其中0~Ⅱ级为HO低分级组，共26例患者（男16例，女10例）；Ⅲ~Ⅳ级为HO高分级组，共19例（男12例，女7例）。采用C(2-7) Cobb角、颈椎总体活动度（ROM）及手术节段ROM评估两组患者的影像学疗效，采用日本骨科学协会（JOA）评分、颈椎功能障碍评分（NDI）和疼痛视觉模拟评分（VAS）评估两组患者的临床疗效，采用手术相邻节段ROM和椎间隙高度评估HO对相邻节段的影响。 结果： 所有患者均定期随访，时间为（98±18）个月。两组患者末次随访时C(2-7) Cobb角和颈椎总体ROM差异均无统计学意义（均P>0.05），而末次随访时HO低分级组手术节段ROM明显高于HO高分级组（7.8°±6.2°比2.6°±1.2°，t=3.60，P<0.05）。两组患者末次随访时JOA评分及恢复率和NDI评分差异均无统计学意义（均P>0.05）。两组患者术前及末次随访时相邻节段椎间隙高度差异均无统计学意义（均P>0.05）。两组患者术前上位和下位相邻节段ROM差异均无统计学意义（均P>0.05），而末次随访时，HO低分级组均明显低于HO高分级组（分别为9.5°±1.1°比10.6°±1.8°和9.4°±1.4°比10.5°±1.7°，t=2.54、2.31，均P<0.05）。 结论： Discover颈椎人工间盘置换术后HO分级高低不影响患者的临床疗效、颈椎曲度和总体ROM。然而，HO分级越高，患者术后手术节段ROM越小，手术相邻节段ROM越大。.
Keywords: Artificial cervical disc replacement; Cervical vertebrae; Heterotopic ossification.