Ⅳa型黏多糖贮积症导致寰枢椎脱位的外科治疗

Surgical strategies of atlantoaxial dislocation in mucopolysaccharidosis IVa

目的探讨Ⅳa型黏多糖贮积症(mucopolysaccharidosis,MPS)导致寰枢椎脱位的外科治疗方法及其疗效。方法回顾性分析2019年4月至2020年10月于上海新华医院脊柱中心采用后路寰枢椎复位减压植骨融合内固定术治疗8例Ⅳa型MPS导致寰枢椎脱位患儿的资料,男6例、女2例;年龄(6.2±3.1)岁(范围2~10岁)。8例患儿均存在下肢乏力、步态不稳,3例患儿无法站立及行走;影像学均表现为齿突发育不全、寰枢椎脱位及全身骨骼发育异常。主要观察指标包括美国脊柱损伤协会(American Spinal Injury Association,ASIA)脊髓损伤分级(ASIA impairment scale,AIS)、校正寰齿前间距(modified atlanto-dental interval,mADI)及复位指数、螺钉植入质量(CT评估)及植骨融合情况。结果手术时间(144.0±43.1)min(范围90~220 min),术中出血量(89.1±55.1)ml(范围15~180 ml),随访时间(17.8±7.4)个月(范围8~27个月)。术前AIS分级C级3例、D级4例、E级1例;末次随访时C级1例、D级1例、E级6例。术前mADI为(7.38±2.62)mm,术后6个月降低至(2.50±1.60)mm,差异有统计学意义(t=5.71,P=0.001);末次随访时复位指数为65.0%±26.3%。共植入椎弓根螺钉31枚,其中Ⅰ型26枚(83.9%)、Ⅱ型4枚(12.9%)、Ⅲ类1枚(3.2%),Ⅲ型螺钉未发生脊髓及血管损伤;另有1例一侧植入棘突椎板钉。5例患者在术后6个月显示融合(均为自体骨),2例术后1年获得融合(异体骨),1例术后2年出现植骨块吸收(异体骨)。1例患儿手术当晚出现Ⅱ型呼吸衰竭,经抢救后康复。其余患者无血管神经损伤、螺钉松动等并发症。结论Ⅳa型MPS患儿绝大多数有齿突缺如,如合并寰枢椎脱位和颈椎管狭窄导致颈脊髓受压,应及时进行手术干预;采用后路寰枢椎复位减压植骨融合内固定术治疗安全、有效。Ⅳa型黏多糖贮积症患儿常合并多系统受累,需要多学科协作来保证围手术期安全。

Objective To discuss the surgical strategies of atlantoaxial dislocation in children with mucopolysaccharidosis IVA.Methods 8 cases of atlantoaxial dislocation in children with mucopolysaccharidosis IVA treated with posterior atlantoaxial reduction,decompression,bone graft and internal fixation from April,2019 to October,2020 were retrospectively analyzed,including 6 males and 2 females,aged 6.2±3.1 years(range,2-10 years).All the 8 children had lower limb weakness and walking instability,and some of them could not even stand and walk,and all of them had odontoid hypoplasia,atlantoaxial dislocation and systemic skeletal dysplasia.Measures,including American Spinal injury Association(ASIA)grade,modified atlanto-dental interval(mADI)and reduction rate,screw placement type and fusion of bone graft,were recorded and analyzed.Results The follow-up time was 17.8±7.4 months(range,8-27 months).The total operation time was 144.0±43.1 mins(range,90-220 min)and the blood loss during the surgery was 89.1±55.1 ml(range,15-180 ml).The ASIA grade were 3 cases of"C"level,4 cases of"D"level and 1 case of"E"level before the operation,and 1 case of"C"level,1 case of"D"level and 6 cases of"E"level at the latest follow-up.The mADI reduced from 7.38±2.62 mm pre-surgery to 2.50±1.60 mm(t=5.71,P=0.001).The reduction rate of the latest follow-up mADI was 65.0%±26.3%.31 pedicle screws were inserted,including 26 Type I screws(83.9%),4 Type II screws(12.9%)and 1 Type III screw(3.2%),and no injury of spinal cord or blood vessels were observed associated with the Type III screw.One unilateral axial lamina screw was used in 1 case.5 patients showed fusion(autogenous bone)6 months after the surgery,2 patients got fusion(allogeneic bone)1 year after the surgery,and other patients showed bone graft resorption(allogeneic bone)at the latest follow-up.One patient developed type II respiratory failure on the night of operation and recovered after rescue.Other patients had no complications such as vascular and nerve injury,screw loosening and so on.Conclusion The majority of children with type IVa mucopolysaccharidosis are accompanied by absence of odontoid process.If such children are complicated with atlantoaxial dislocation and cervical spinal canal stenosis resulting in cervical spinal cord injury,timely surgical intervention should be carried out.Posterior atlantoaxial fusion is a safe and effective surgical method.As children have the characteristics of multi-system involvement,multi-disciplinary cooperation may be needed to ensure perioperative safety.