神经外科手术机器人置入椎弓根螺钉的精准性

目的 探讨神经外科手术机器人在人体腰椎模型进行椎弓根螺钉置入的精准性。方法 利用O型臂影像系统对模型进行正侧位扫描，并三维重建，获取3D-CT数据，传入手术机器人系统，规划椎弓根螺钉的最佳进钉点和进钉方向。手术机器人系统利用3D-CT数据自动注册后，置入椎弓根螺钉。应用置钉前后的3D融合图像，按照Gertzbein-Robbins分级评估置钉的准确性。结果 共置入39枚椎弓根螺钉，其中37枚螺钉完全位于椎弓根内，2枚螺钉突破椎弓根的内壁2 mm以内。螺钉与原规划钉道的平均偏移距离为（1.45±0.67）mm。螺钉在进钉点的滑移方向:内下方16枚（41.03%），外上方6枚（15.38%），下方6枚（15.38%），外下方5枚（12.82%），内上方4枚（10.26%），内方1枚（2.56%），上方1枚（2.56%）。结论 神经外科手术机器人置入椎弓根螺钉具有较高的精准性。     

Accidental external rotation of distal interlock jig in retrograde femoral nailing can lead to more prominent screws

Objective

Symptomatic distal interlocking screws in retrograde femoral nailing are common due the difficulties of imaging the trapezoidal femur. Screws appearing to have appropriate length on imaging may possibly be prominent, creating symptoms. Screw trajectory may influence the degree of this radiographic error. We hypothesize that external rotation of screw trajectory will increase measurement error of screw length.

Analysis of an in-house technique for temporary mandibulotomy and its impact on postoperative radiotherapy

The purpose of this study was to describe a newly developed procedure for temporary mandibulotomy and subsequent osteosynthesis. Clinical outcomes were evaluated, including complications and the impact on postoperative treatment, particularly postoperative radiotherapy. Twenty-four patients underwent temporary mandibulotomies for the surgical resection of malignancies located in the posterior oral or oropharyngeal region. All were treated with postoperative radiotherapy. An angulated median mandibulotomy was followed by osteosynthesis with three anchor screws directed towards the inferior aspect of the mandible. Anchor screws are modified conventional lag screws that include an additional biconcave washer. This modification prevents the screw heads from cracking into the cancellous bone during tightening, improving their biomechanical qualities considerably. Insertion of screws at any angle to the bony surface therefore becomes possible, which is a precondition for this technique. Minor complications occurred in two patients in the early postoperative period. However, complications causing bony non-union, leading to postponed postoperative radiotherapy were not noted in this cohort.     

Focal hole versus screw stimulation to prevent false negative results in detecting pedicle breaches during spinal instrumentation

ObjectiveWe describe a stimulus-evoked EMG approach to minimize false negative results in detecting pedicle breaches during lumbosacral spinal instrumentation.MethodsIn 36 patients receiving 176 lumbosacral pedicle screws, EMG threshold to nerve root activation was determined using a focal probe inserted into the pilot hole at a depth, customized to the individual patients, suitable to position the stimulating tip at the point closest to the tested nerve root. Threshold to screw stimulation was also determined.ResultsMean EMG thresholds in 161 correctly fashioned pedicle instrumentations were 7.5 mA ± 2.46 after focal hole stimulation and 21.8 mA ± 6.8 after screw stimulation. Direct comparison between both thresholds in individual pedicles showed that screw stimulation was always biased by an unpredictable leakage of the stimulating current ranging from 10 to 90%. False negative results were never observed with hole stimulation but this was not true with screw stimulation.ConclusionsFocal hole stimulation, unlike screw stimulation, approaches absolute EMG threshold as shown by the lower normal limit (2.6 mA; p < 0.05) that borders the upper limit of threshold to direct activation of the exposed root.SignificanceThe technique provides an early warning of a possible pedicle breakthrough before insertion of the more harmful, larger and threaded screw.     

CT三维重建模型下模拟髋臼前柱2种经皮置钉方法的比较

目的对比CT三维重建模型下模拟髋臼前柱2种经皮置钉方法的效果。方法选取55例正常成人骨盆CT资料构建三维模型,共110侧髋臼前柱,调整模型透明度使其类似常规X线片,分别用2种置钉方法进行置钉,A组利用出口闭孔位和入口髂骨位引导置钉,B组利用髋臼前柱轴位引导置钉,置钉完成后恢复图像为不透明状态,记录螺钉是否进入髋关节及与耻骨支的位置关系。结果55例110侧髋臼,4侧未能找到髋臼前柱轴位影像予以剔除,106侧髋臼前柱纳入研究。2组模型均无螺钉进入髋臼。A组螺钉置入优秀、良好、尚可率分别为59.4%、17.0%、23.6%,B组分别为59.4%、22.6%、17.9%,2组总体置钉质量差异无统计学意义(Z=-0.829,P=0.407)。A组女性骨盆置钉优秀、良好、尚可率分别为7.1%、21.4%、71.4%,B组分别为28.6%、21.4%、50.0%,B组置钉质量显著高于A组(Z=-3.000,P=0.003)。A组男性骨盆置钉优秀率78.2%,良好率15.4%,尚可率6.4%,B组分别为70.5%、23.1%、6.4%,2组差异无显著性(Z=-0.969,P=0.333)。结论髋臼前柱轴位可以作为引导置钉的一种手段,尤其适用于女性患者,对于男性患者,2种方法均可实现较好的置钉。     

采用椎弓根螺钉内固定治疗寰枢椎骨折脱位

[目的]探讨寰枢椎椎弓根螺钉技术治疗创伤性寰枢椎不稳的临床效果。[方法]2009年9月~2017年3月,对6例创伤性寰枢椎不稳患者采用颈椎后路寰枢椎椎弓根螺钉固定技术治疗。术前均常规行颅骨牵引,椎弓根进钉点位于寰椎椎弓两侧距后结节20 mm、后弓下缘2 mm,内倾5°~10°、头倾10°~15°,置入直径3.5 mm、长22~26 mm螺钉。枢椎螺钉的进钉点位于侧块内上象限,内倾约25°,头倾约25°置入直径3.5 mm、长24~28 mm螺钉。[结果]术中无血管及神经损伤。术后随访6~36个月,患者临床症状得到明显改善。术后检查显示螺钉位置良好,无内置物松动、断裂。术后12个月JOA评分为11.00~17.00分。[结论]寰枢椎椎弓根螺钉固定治疗创伤性寰枢椎不稳疗效满意。     

可吸收明胶海绵棒在椎弓根内止血的应用

[目的]观察评价可吸收明胶海绵棒在椎弓根置钉过程中的止血效果。[方法]2017年10月~2018年6月,48例胸腰椎骨折即将行后路手术的患者纳入本研究,采用随机数字表法分为明胶海绵组和骨蜡组。明胶海绵组共23例,置钉过程中应用明胶海绵棒填塞至椎弓根孔道止血;骨蜡组共25例,在透视定位时应用骨蜡封闭椎弓根孔道。记录置钉情况;记录术中出血量、自体血回输量、置钉过程中的出血量、输血量;检测术前和术后5 d RBC、HB和HCT。[结果]两组在置钉总数、伤椎置钉数、伤椎位置各椎置钉数量的差异均无统计学意义(P>0.05)。术后两组各出现1例小腿肌间静脉血栓,抗凝治疗后于复查时消失。术后两组均无明胶海绵或骨蜡导致的不良反应。两组在术中出血量、术中自体血回收量、输血量的差异无统计学意义(P>0.05),但明胶海绵组上述指标均小于骨蜡组。每钉置入过程中明胶海绵组的出血量显著少于骨蜡组,差异有统计学意义(P<0.05)。两组术后5 d的RBC、HB和HCT均较术前显著减少,两时间点间差异均有统计学意义(P<0.05)。术前两组在RBC、HB和HCT的差异均无统计学意义(P>0.05),术后5 d两组在RBC、HB和HCT的差异亦均无统计学意义(P>0.05)。[结论]应用明胶海绵棒填塞椎弓根孔道止血可显著减少安置椎弓根螺钉过程中的出血,是一种简单、安全、有效的脊柱外科术中止血方法。