Objective: To investigate the effect of modified lateral mass screws implantation strategy on axial symptoms in cervical expansive open-door laminoplasty.
Methods: A clinical data of 166 patients, who underwent cervical expansive open-door laminoplasty between August 2011 and July 2016 and met the selection criteria, was retrospective analyzed. Among them, 81 patients were admitted before August 2014 using the traditional mini-plate placement and lateral mass screws implantation strategy (control group), and 85 patients were admitted after August 2014 using modified lateral mass screws implantation strategy (modified group). There was no significant difference in the gender composition, age, clinical diagnosis, disease duration, diseased segment, and preoperative Japanese Orthopaedic Association (JOA) score, pain visual analogue scale (VAS) score, Neck Disability Index (NDI), cervical curvature and range of motion, spinal canal diameter and cross-sectional areas, and Pavlov's value between the two groups ( P>0.05). The operation time, intraoperative blood loss, the number of facet joints penetrated by lateral mass screws, effectiveness evaluation indexes (JOA score and improvement rate, VAS score, NDI), imaging evaluation indexes (cervical curvature and range of motion, spinal canal diameter and cross-sectional areas, Pavlov's value, and lamina open angle), and complications were recorded and compared between the two groups.
Results: The modified group had shorter operation time and lower intraoperative blood loss than the control group ( P<0.05). There were 121 (29.9%, 121/405) and 10 (2.4%, 10/417) facet joints penetrated by lateral mass screws in control and modified groups, respectively; and the difference in incidence was significant ( χ 2=115.797, P=0.000). Eighteen patients in control group had 3 or more facet joints penetrated while no patients in modified group suffered 3 or more facet joint penetrated. The difference between the two groups was significant ( P=0.000). All patients were followed up, the follow-up time was (28.7±4.9) months in modified group and (42.4±10.7) months in control group, showing significant difference ( t=10.718, P=0.000). The JOA score, VAS score, and NDI at last follow-up of the two groups were significantly improved compared with preoperative ( P<0.05); there was no significant difference in JOA score and improvement rate and VAS score between the two groups ( P>0.05), but the NDI was significantly lower in modified group than in control group ( P<0.05). There were significant differences in cervical curvature and range of motion, spinal canal diameter, Pavlov's value, and cross-sectional areas at last follow-up when compared with those before operation in both groups ( P<0.05). There was no significant difference in the above indicators and lamina open angle between the two groups ( P>0.05). The modified group has a relative lower axial symptom rate (23/85, 27.1%) than the control group (27/81, 33.3%), but the difference was not significant ( Z=-1.446, P=0.148). There was no significant differences between the two groups in the incidences of C 5 nerve root palsy, cerebrospinal fluid leakage, wound infection, and lung or urinary tract infection ( P>0.05).
Conclusion: In the cervical expansive open-door laminoplasty, the modified lateral mass screws implantation strategy can effectively reduce the risk of lateral mass screw penetrated to the cervical facet joints, and thus has a positive significance in avoiding the axial symptoms caused by facet joint destruction.
目的: 探讨颈椎单开门椎管扩大椎板成形术中采用改良微型钢板侧块固定螺钉植钉策略对术后轴性症状发生的影响。.
方法: 回顾分析 2011 年 8 月—2016 年 7 月 166 例行颈椎单开门椎管扩大椎板成形术且符合选择标准患者的临床资料，其中 81 例 2014 年 8 月前收治患者采用传统微型钢板安放及侧块固定螺钉植钉方法（对照组），85 例 8 月后收治患者采用改良植钉策略手术（改良组）。两组患者性别构成、年龄、临床诊断、病程、病变节段以及术前日本骨科协会（JOA）评分、疼痛视觉模拟评分（VAS）、颈椎功能障碍指数（NDI）、颈椎曲度及活动度、椎管矢状径及横截面积、Pavlov 值等一般资料比较，差异均无统计学意义（ P>0.05）。记录并比较两组手术时间、术中出血量及侧块固定螺钉破坏颈椎小关节数量、临床疗效评价指标（JOA 评分及改善率、VAS 评分、NDI）、影像学评价指标（颈椎曲度及活动度、椎管矢状径及横截面积、Pavlov 值、椎板开门角度），以及并发症发生情况。.
结果: 改良组手术时间、术中出血量明显低于对照组（ P<0.05）。术中改良组破坏颈椎小关节 10 个（2.4%，10/417）、对照组破坏 121 个（29.9%，121/405），发生率差异有统计学意义（ χ 2=115.797， P=0.000）；对照组 18 例颈椎小关节破坏达 3 个或以上，改良组无破坏超过 3 个患者，差异有统计学意义（ P=0.000）。患者术后均获随访，改良组随访时间为（28.7±4.9）个月，对照组为（42.4±10.7）个月，差异有统计学意义（ t=10.718， P=0.000）。两组末次随访时 JOA 评分、VAS 评分及 NDI 均较术前明显改善（ P<0.05）；两组间 JOA 评分及改善率、VAS 评分差异均无统计学意义（ P>0.05），但改良组 NDI 明显低于对照组（ P<0.05）。影像学复查显示，末次随访时两组颈椎曲度、颈椎活动度、椎管矢状径、Pavlov 值、椎管横截面积与术前比较，差异均有统计学意义（ P<0.05）；两组间上述指标以及椎板开门角度比较，差异均无统计学意义（ P>0.05）。随访期间对照组轴性症状发生率（27/81，33.3%）低于改良组（23/85，27.1%），但差异无统计学意义（ Z=−1.446， P=0.148）。两组 C 5 神经根麻痹、脑脊液漏、切口感染、肺部及泌尿系感染发生率比较，差异均无统计学意义（ P>0.05）。.
结论: 颈椎单开门椎管扩大椎板成形术中采用改良微型钢板侧块固定螺钉植钉策略，可有效降低螺钉破坏颈椎小关节的风险，对避免因小关节破坏导致的轴性症状具有积极意义。.
Keywords: Cervical spine; axial symptom; expansive open-door laminoplasty; lateral mass screw; mini-plate; screw implantation strategy.