人工腰椎间盘置换术后异位骨化的危险因素及其对策

目的总结引起人工腰椎间盘置换术后异位骨化的危险因素并探讨预防对策。方法随访1998年4月至2003年12月使用SB CharitéⅢ假体进行的人工腰椎间盘置换术患者共65例78个间隙,收集其所有X线片。由独立的2名放射科医师和1名骨科医师,根据M cA fee的评价系统,对术后X线片显示的异位骨化进行分级,测量该节段的活动度,记录各级异位骨化的发生时间并分析其可能的潜在危险因素。结果共有9例患者的10个椎间隙发生了不同程度的异位骨化。Ⅰ级异位骨化(7例)发生于术后平均2.1年,手术节段活动度正常,其中3例于此后2.5年内发展为Ⅱ~Ⅲ级,平均活动度为10°。2例术前已有纤维环钙化的患者,术后2年即发现Ⅲ级异位骨化,平均活动度为9°,但在术后6年发展为Ⅳ级,活动度为0°和4°。9例异位骨化病例中,共有8例发现可能诱发异位骨化的危险因素共11例次,其中术前纤维环钙化2例次,终板损伤5例次,假体下沉2例次,假体植入位置严重偏斜2例次。结论人工腰椎间盘置换术后异位骨化的危险因素有:术前纤维环钙化、术中终板损伤、假体植入位置严重偏斜及术后假体下沉,但大部分椎间隙的活动仍然得到保持。严格掌握手术适应证,预防上述危险因素的发生,可有效减少术后异位骨化的形成。

The risk factors and preventive strategies of heterotopic ossification after artificial disc replacement in lumbar spine

OBJECTIVE: To analyze the risk factors of heterotopic (HO) ossification after total lumbar disc replacement and probe the preventive strategies for it. METHODS: The radiographs and clinical data of 78 discs in 65 patients who received artificial lumbar disc replacement (ADR) from April 1998 to December 2003 were analyzed retrospectively by two radiologists and one orthopaedic surgeon and then postoperative HO were graded according to McAfee system. The bony formations in disc spaces, time of HO were found, and range of motion (ROM) of the operated levels were measured on radiographic films. In addition, the risk factors such as preoperative peri-annulus ossification, bony endplates injuries, and subsided or mal-position of the prostheses were also analyzed by Logistic regression analysis. RESULTS: Postoperative HO was found in 10 spaces of 9 cases. Class I of HO were occurred in 7 patients at means 2.1 years postoperatively with normal range of motion preserved. Three of them turned into class II or III with 10 degrees of mean ROM in the following 2.5 years. Another 2 (2/9) cases with preoperative peri-annulus ossification had bridging trabecular bone (class III) between the endplates and 9 degrees of ROM 2 years after surgery, then turned into class IV at 6 years with 0 degrees and 4 degrees of motion in the operated levels. As the risk factors of HO, preoperative annulus ossification (2 cases), bony endplates injuries (5 cases), mal-positioned prostheses (2 cases) and subsided prostheses (2 cases) were found simultaneity with significant positive relation to HO occurred (P < 0.05). CONCLUSIONS: Factors such as preoperative ossification of annulus, endplate injuries, prosthesis subsided and mal-position would have higher risks to have HO occurred after ADR, but ROM of most affected levels are preserved. Strict control indication and avoid all above risk factors can prevent HO occurring effectively.