青少年先天性半椎体脊柱侧凸畸形的手术治疗

[目的]探讨治疗青少年先天性半椎体脊柱侧凸畸形的手术方法及治疗效果。[方法]对18例青少午先天性半椎体脊柱侧凸患者,按照术式分为侧前路矫正、前后路联合矫正。首先通过胸腰段、腰段脊柱侧凸的半椎体、椎间盘切除,然后采用侧前路短节段椎体螺钉固定,旋转棒的三维旋转矫正脊柱的畸形7例;采用前后路联合入路,经后路行残余半椎体的关节突、椎板切除,凸侧加压、凹侧支撑固定11例。[结果]18例患者中侧凸平均矫正Cobb's角36.7°,矫正率77%,经18~28个月随访,达到满意的矫形效果,丢失率低,融合良好。[结论]小儿半椎体畸形应早期手术治疗。侧前路和前、后路联合半椎体切除临床效果满意,其中前路矫正手术用于胸腰椎、腰椎单一半椎体畸形。     

胸腰段脊柱侧凸前路矫正术后并发症的预防及护理

目的：观察胸腰段脊柱侧凸前路矫正术后对症护理的效果。方法：2000年10月--2002年2月应用中华长城内固定系统对68例胸腰段脊柱侧凸患者进行了前路手术矫正，护理过程中，加强了胸腔闭式引流管护理疼痛护理、及神经血管损伤牵拉引起并发症的预防和护理。结果：本组术后均1—2d拔除胸腔闭式引流管，未出现心肺功能异常；术后止痛治疗40--60h，疼痛均得到了有效控制；术后9—11h出现恶心呕吐症状者有6例，术后1d以后均得到缓解；术后出现单侧下肢皮温异常症状者4例，术后3d下肢皮温恢复正常，无严重并发症，保持了脊柱平衡，重塑了外观形象。结论：抓住胸腰段脊柱侧凸矫正手术的每一个环节对症护理，效果显著。     

前后路矫形融合术治疗胸腰段/腰段青少年特发性脊柱侧凸(PUMC Ⅰb/Ⅰc/Ⅱd1型)

目的比较前后两种入路及手术方法治疗特发性胸腰段／腰段脊柱侧凸的疗效。方法青少年特发性脊柱胸腰段／腰段侧凸（PUMC Ⅰb，Ⅰc，Ⅱd1型）患者28例，分为两组。A组16例，平均14．88岁，行前路短节段矫形融合术；B组12例，平均15．50岁，行后路、椎弓根系统矫形融合术。两组均采用第三代坚强矫形内固定器械。比较两组术前一般资料和术中情况，并通过X线参数，比较两种手术的矫形效果和躯干平衡的矫正情况。结果两组术前资料无显著差异，术后均无严重手术并发症，融合效果满意。A组手术时问、术中出血及输血量、内固定材料花费明显少于B组；A组平均融合4．25个节段，B组平均融合5．95个节段。随访时间12-47个月，A组术后冠状面矫正率是82％，随访时72％；B组术后冠状面矫正率是74％，随访时70％。矢状面矫形效果均满意，两组无显著性差异；A组术后即刻躯干偏移矫正不如B组，但随访时，两组无差异。两组在矫正顶椎旋转和顶椎偏移方面无显著差异。结论前路矫形和后路椎弓根系统矫形融合术治疗轻中度胸腰段／腰段青少年特发性脊柱侧凸，均可获得满意的矫形效果，但前路融合可缩短手术时间和减少术中出血、输血量，并能保留较多运动节段。     

前路Moss Miami器械矫形治疗特发性胸腰段或腰段脊柱侧凸

目的:评价MossMiami前路矫形系统对特发性胸腰段或腰段脊柱侧凸的手术效果。方法:对21例胸腰段或腰段特发性脊柱侧凸患者经前路胸腹联合入路行MossMiami矫形内固定,自体肋骨椎间植骨融合术。测量手术前后Cobb角以及躯干侧方位移。结果:Cobb角术前平均53°,术后平均5°,矫正率为90%。上方代偿性胸椎侧凸术前平均17°,术后矫正至平均5°。下方代偿性腰骶椎侧凸术前平均43°,术后自发矫正至19°。随访12~24个月,Cobb角平均丢失19.7°,胸腰段(T11~L1)术前平均前凸0.3°(0~4°),术后平均后凸3°(0~5°)。躯干侧方位移从术前平均26mm矫正至术后5mm。1例术后出现一侧下肢交感神经切断症状,2例术后并发气胸。无感染、截瘫及内固定失败等并发症发生。结论:MossMiami前路器械具有操作简单和低切迹的优点。棒的预弯、去旋转矫形、正确选择螺钉置入部位和椎间植骨可防止固定节段后凸畸形的形成。对Risser征小于4度的患者应密切观察上方代偿性胸椎侧凸进展情况。     

KASS内固定治疗胸腰段脊柱侧凸畸形

[目的]评价应用Kaneda脊柱前路矫形系统(Kaneda anterior scoliosis system,KASS)治疗胸腰椎侧凸畸形的临床疗效。[方法]回顾分析43例脊柱侧凸畸形通过前路椎间盘摘除、松解、椎间植骨融合及KASS内固定矫正侧凸畸形的临床资料,男性17例,女26例。年龄11~24岁(平均14.6岁)。侧弯病因:特发性35例,先天性8例。[结果]所有患者均达到满意矫正效果,平均随访时间为22个月(6个月~4年)。胸腰椎术前侧凸Cobb s角平均为66°(43°~98°),术后矫正至18°(0°~32°),畸形矫正率为91.7%。无明显并发症出现。术后随访3例出现矫正度部分丢失。[结论]KASS内固定系统治疗脊柱侧凸具有能早期矫正畸形,创伤小,融合固定节段少,矫形效果好,维持术后矫正度理想等优点,是一种值得推广的手术方法。     

胸腰段特发性脊柱侧凸的前路矫正术

目的评价胸腰段/腰段特发性脊柱侧凸经前路矫正术的临床效果。方法1998年1月~2004年1月,76例胸腰段/腰段特发性脊柱侧凸患者接受前路选择性矫正融合术。患者共76例,男19例,女57例,平均年龄为16.2岁(13~27岁)。按照Lenke分型,Ⅴ型41例,Ⅵ型35例。其中Lenke Ⅴ型术前胸腰段侧凸Cobb角平均51.3°(38°~65°),胸段侧凸Cobb角平均35.5°(23°~41°);Lenke Ⅵ型术前胸腰段侧凸Cobb角平均53.4°(46°~68°),胸段侧凸Cobb角平均39.2°(27°~51°)。所有患者均接受侧前路矫正选择性胸腰段融合。术后以及随访中对胸腰段侧凸矫正以及胸段代偿矫正情况进行分析对比,同时采用SRS-22评分评价患者手术前后的功能状况。结果患者均安全完成手术,无严重并发症发生。所有患者均随访2年以上(2~5年)。Lenke Ⅴ型组术后胸腰段侧凸Cobb角平均11.2°(3°~15°),胸段侧凸Cobb角平均8.3°(2°~11°),最终随访时分别为13.2°(5°~17°)和10.1°(4°~15°),无躯干冠状面失代偿发生;LenkeⅥ型组术后Cobb角平均16.3°(8°~21°),胸段侧凸Cobb角平均13.7°(11°~19°),最终随访时分别为17.5°(11°~24°)和15.2°(14°~21°);仅1例发生躯干冠状面失代偿,但不需要进一步治疗。两组之间无统计学差异。所有患者均在术后以及最终随访时填写了SRS-22评分表,结果显示两组患者均对治疗结果表示满意。结论胸腰段/腰段特发性脊柱侧凸经前路矫正、选择性融合可以获得良好矫正,术后胸段弯曲能够获得较好的代偿矫正,并在远期随访中维持矫正效果和躯干冠状面的平衡。     

GSS器械在手术矫正脊柱侧凸畸形的临床应用

[目的]介绍GSS器械的结构，原理并观察其临床应用效果。[方法]GSS器械由不同型号的开13椎弓根螺钉、开13椎弓根钩、连接棒、阻塞器和横向连接器等组成。在脊柱侧凸稳定区内的各脊柱节段上选择数枚开13椎弓根螺钉行连续或间断固定，通过连接棒进行连续固定，采用撑开、加压或旋转矫正的方法对畸形脊柱进行矫正。共治疗16例脊柱侧凸患者，平均年龄15．3岁。特发性侧凸11例，先天性侧凸5例；术前平均Cobb’s角为63°。16例均采用一次性手术矫正。[结果]14例患者进行了随访，最短6个月，最长4年，平均1．5年。特发性脊柱侧凸患者，手术后平均Cobb’s角为29．4°，矫正率为59．1％；先天性脊柱侧凸患者，手术后平均Cobb’s角为33．3°，矫正率为52．3％。无并发症发生。[结论]根据CD矫正器的原理设计的GSS器械，对脊柱具有撑开、加压及旋转矫正功能，适用于不同年龄脊柱侧凸患者的内固定器械，其矫正力大，且不占据椎管空间，是对脊柱侧凸治疗有效的方法。     

青少年麻痹性脊柱侧凸前后路手术治疗分析

目的　探讨青少年麻痹性脊柱侧凸安全有效的治疗方法。方法　对 18例青少年麻痹性脊柱侧凸 (侧凸角度 (Cobbs法 ) 70°～ 130°,平均 85°。后凸角度 ,70°～ 80°,平均为 45°)患者采用脊柱前路松解 ,后路器械矫正、固定的方法治疗。结果　经 10月～ 2年 2月随访 ,平均 1年 8月 ,术后侧凸矫正 6 0°～ 95°,平均 6 5°,后凸矫正 7°～ 5 4°,平均 34°,无一例发生严重并发症。结论　脊柱前路松解 ,后路器械矫正固定术对青少年麻痹性脊柱侧凸的治疗具有明显的治疗效果     

脊柱侧凸前路手术治疗的远期疗效

目的 :评价前路手术治疗脊柱侧凸的远期疗效。方法 :1980年 1月～ 2 0 0 1年 1月 ,前路手术治疗 168例胸腰段或腰段脊柱侧凸 ,男 5 3例 ,女 115例 ,年龄 7～ 3 1岁 ,平均 14 2岁。术前冠状面Cobb角 3 4～ 89° ,平均 47 5°。随访期间测量冠状面Cobb角 ,了解畸形矫正情况。结果 :15 1例患者随访 3～ 2 4年 ,平均 12 5年 ,术后矫正 2 6～ 45° ,平均矫正 41° ( 85 4% ) ,平均矫正丢失 3 2° ( 7 1% )。脊髓损伤 1例 ,肠系膜上动脉压迫症 4例 ,螺丝钉折断 2例 ,钢缆折断 3例 ,断棒 3例 ,假关节形成 2例。结论 :前路矫形手术能有效地治疗胸腰段或腰段脊柱侧凸 ,能通过较短的节段达到三维矫正和重建躯干平衡。     

应用KASS系统前路矫正治疗特发性脊柱侧凸

[目的]探讨应用KASS系统前路矫正治疗特发性脊柱侧凸的临床效果。[方法]应用KASS系统治疗总123例病例。根据King分型法可分为：胸椎侧凸47例（其中Ⅱ型13例，Ⅲ型18例，Ⅳ型16例），胸腰椎或腰椎侧凸76例。所有病例中均对主要侧凸部位行前路矫形手术，平均随访7年7个月（2年～13年6个月）。[结果]所有病例均获骨性融合，胸椎生理性后凸和腰椎生理性前凸基本正常。胸椎侧凸部位矫正率为68％，胸腰椎或腰椎侧凸矫正率为81％。胸椎最底椎水平倾斜改善率分别为78％和83％，顶椎旋转矫正率分别为59％和70％。无神经血管及内置物引发的并发症。[结论]KASS系统可提供强有力的三维矫正效果，且融合节段少。     

重度脊柱双侧凸的前后路手术治疗

目的: 通过前后路二次手术治疗重度脊柱双侧凸, 评价其治疗效果。方法: 1999年12月至今, 16例重度双侧凸患者, 采用前后路两次手术矫形, 矫正其在冠状面和矢状面的畸形。结果: 16例病例通过手术矫形, 胸段侧凸矫正率79%, 腰段83%, 腰椎后凸恢复成生理前凸, 椎体旋转度提高Ⅱ~Ⅲ度。结论: 通过前后路分次手术矫形, 可以对严重的、复杂的畸形进行有效的矫正, 彻底改变严重畸形的外观, 达到了良好的手术效果。     

中华长城椎弓根螺钉系统治疗胸腰椎爆裂骨折

目的 介绍中华长城椎弓根螺钉系统(CGWS)在胸腰椎爆裂性骨折治疗中的效果。方法 隙采用中华长城惟弓根螺钉系统治疗胸腰椎爆裂性骨折18例。结果 术后及随访期间拍X线片测定Cobb角、椎体成角、上下终板成角、椎体前缘高度与正常高度的比值均明显改善，随访期间测量以上结果与术后相比无明显变化。结论 中华长城椎弓根螺钉系统足一种新型的多功能脊椎三维矫形内固定器械，具有材料优良、矫正效果显著、安装操作方便、固定确切、安全可靠等优点。     

Segmental pedicle screw instrumentation in idiopathic thoracolumbar and lumbar scoliosis

The role of posterior correction and fusion in thoracolumbar and lumbar scoliosis as well as pedicle screw instrumentation in scoliosis surgery are matters of debate. Our hypothesis was that in lumbar and thoracolumbar scoliosis, segmental pedicle screw instrumentation is safe and enables a good frontal and sagittal plane correction with a fusion length comparable to anterior instrumentation. In a prospective clinical trial, 12 consecutive patients with idiopathic thoracolumbar or lumbar scolioses of between 40° and 60° Cobb angle underwent segmental pedicle screw instrumentation. Minimum follow-up was 4 years (range 48– 60 months). Fusion length was defined according to the rules for Zielke instrumentation, normally ranging between the end vertebrae of the major curve. Radiometric analysis included coronal and sagittal plane correction. Additionally, the accuracy of pedicle screw placement was measured by use of postoperative computed tomographic scans. Major curve correction averaged 64.6%, with a loss of correction of 3°. The tilt angle was corrected by 67.0%, the compensatory thoracic curve corrected spontaneously according to the flexibility on the preoperative bending films, and led to a satisfactory frontal balance in all cases. Average fusion length was the same as that of the major curve. Pathological thoracolumbar kyphosis was completely corrected in all but one case. One patient required surgical revision with extension of the fusion to the midthoracic spine due to a painful junctional kyphosis. Eighty-five of 104 screws were graded “within the pedicle”, 10 screws had penetrated laterally, 5 screws bilaterally and 4 screws medially. No neurological complications were noted. In conclusion, despite the limited number of patients, this study shows that segmental pedicle screw instrumentation is a safe and effective procedure in the surgical correction of both frontal and sagittal plane deformity in thoracolumbar and lumbar scoliosis of less than 60°, with a short fusion length, comparable to anterior fusion techniques, and minimal loss of correction. Received: 23 September 1999 Revised: 20 January 2000 Accepted: 26 January 2000     

脊柱侧凸三维矫形术的早期并发症及其预防

目的:探讨脊柱侧凸三维矫形手术的早期并发症及其防治。方法:1995年6月至2003年4月,应用中华长城椎弓根三维矫形系统治疗各型脊柱侧凸487例,男性96例,女性391例;年龄8~33岁,平均14.3岁。术前侧凸Cobb角35°~135°,平均86.6°;后凸5°~68°,平均28.4°。结果:全组病例均安全完成矫形手术,侧凸矫正率45%~98%,平均82.3%,后凸矫正率23%~56%,平均35.8%。术中、术后无脊髓损伤,其它并发症共发生139例次。结论:三维矫正脊柱侧凸仍存在不少并发症,但如术前准备充分、术中术后处理得当,脊髓、神经损伤可获得有效预防。     

选择性胸椎融合治疗脊柱侧凸合并脊髓空洞症

目的 评价选择性胸椎融合治疗脊柱侧凸并脊髓空洞症的效果.方法 对2001年1月至2009年1月收治的93例脊柱侧凸并脊髓空洞症患者进行回顾性分析,其中行选择性胸椎融合且术后随访超过2年的患者共11例,男性3例,女性8例;年龄9～21岁,平均14.9岁.侧凸类型包括双弯9例,三弯2例.术前、术后及随访时行X线片检查,对侧凸类型、侧凸Cobb角、顶椎旋转度、顶椎偏距、侧凸柔韧性、躯干偏移进行测量和分析.结果 术前胸腰凸或腰凸Lenke A型2例,LenkeB型7例,Lenke C型2例.手术前后胸凸Cobb角平均值分别为62.6°和19.0°,平均矫正率为69.6%;手术前后胸腰凸或腰凸Cobb角分别为36.1°和11.6°,自动矫正率为67.9%,随访时间24～48个月,平均29.5个月,胸凸矫正丢失率为6.8%.最终随访时有1例发生了冠状面躯干失平衡,有1例发生椎弓根螺钉螺帽脱出,行翻修手术,无神经系统并发症发生.结论 选择性胸椎融合可用于脊柱侧凸并脊髓空洞症患者的手术治疗,这类患者的胸腰凸或腰凸具有与特发性脊柱侧凸类似的自发矫形能力,参照特发性脊柱侧凸的选择性融合标准可获得良好效果.

Abstract：

Objective To evaluate the surgical results of selective thoracic fusion(STF)for scoliosis associated with syringomyelia Methods From January 2001 to January 2009,93 cases of scoliosis associated with syringomyelia were retrospectively reviewed.There were 11 cases who underwent STF and were followed up more than 2 years,which included 8 female and 3 male,the mean age was 14.9 years (9-21 years).Curve type,coronal and sagittal Cobb angle,apical vertebral rotation apical vertebral translation,flexibility,trunk shift were recorded and analyzed.Results There were 9 double curves and 2 triple curves,the Lenke type of thoracolumbar/lumbar curve included Lenke A in 2 cases,Lenke B in 7 cases and Lenke C in 2 cases.The average coronal Cobb angle of thoracic curve before and after surgery were 62.6°and 19.0° respectively,and the average correction rate was 69.6%.The average coronal Cobb angle of thoracolumbar/lumbar curve before and after surgery were 36.1° and 11.6° respectively,and the average spontaneous correction rate was 67.9%.The followed up time ranged from 24 to 48 months(mean 29.5 months),the average loss of correction rate was 6.8%.Only one trunk decompensation was noted at final follow-up.Pedicle screw nut loosening occurred in one patient and this patient underwent revision surgery,no neurological complication was noted at final follow-up.Conclusions STF could be safely performed in scoliosis associated with syringomyelia.Thoracolumbar/lumbar curve in these patients has similar spontaneous correction ability compared with idiopathic scoliosis patients.The satisfactory result could be achieved according to the STF criteria for IS.     

胸腰椎骨折内固定术后椎弓根螺钉断裂的原因分析及对策

目的：探讨胸腰椎骨折内固定术后椎弓根螺钉断裂的原因以及预防措施。方法：对2000年6月至2006年9月应用椎弓根螺钉内固定系统治疗的273例资料完整的胸腰椎骨折病例进行回顾性分析,按照骨折类型、植骨融合方式、是否使用横杆以及内固定取出时间对椎弓根螺钉断裂者进行统计学分析。结果：发生椎弓根螺钉断裂22例，椎弓根螺钉断裂平均发生时间为术后19．9个月，大多（19／22）在取内固定物前复查X线片时发现。断钉发生率：爆裂型骨折患者（13／76）显著高于压缩型骨折（6／132）和骨折脱位型患者（3／65）（P〈0．01）；椎间植骨组（1／25）和后外侧植骨组（7／110）显著低于未植骨组（7／70）（P〈O．05）；未使用横杆组（8／49）显著高于使用横杆组（14／224）（P〈O．05）；术后12个月以上取出内固定组（9／97）高于6～12个月取出内固定组（6／169）（P〈O．05）。结论：椎弓根螺钉断裂可能与手术方式选择不当、植骨融合不当、未正确使用横连杆、内置物取出过迟有关。严格掌握手术适应证和手术时机、有效植骨融合、合理使用横杆以及及时取出内固定可有效防止椎弓根螺钉断裂发生。     

骶骨肿瘤切除与骶骨重建方式探讨

目的 探讨骶骨肿瘤切除和骶骨重建方式. 方法 对13例原发性骶骨肿瘤患者行肿瘤切除及骶骨重建,骶骨部分切除12例,全骶骨切除1例.全骶骨切除术后给予腰椎与髂骨中华长城内固定器加腓骨植骨术重建后骨盆环,并给予相应的放疗与化疗. 结果 术后近期疗效均较满意,患者腰骶部疼痛及神经功能有不同程度改善.本组13例中,1例术后出现排尿困难,1例术后出现脑脊液瘘,1例术后切口感染延期愈合,术后随访6个月～10年,有5例肿瘤复发或转移死亡. 结论 肿瘤的切除方式和骶骨重建及术后综合治疗对预后具有重要的影响,而减少术中出血、保留马尾神经功能以及重建高位骶骨肿瘤术后骨盆负重功能则是提高疗效的关键.     

2- to 4-year outcome of dorsal double rod instrumentation spondylodesis in idiopathic scoliosis]

INTRODUCTION: In order to evaluate the results of posterior correction and fusion using the Münster Posterior Doublerod-System (MPDS) 48 patients with idiopathic scoliosis were studied prospectively. METHODS: All patients underwent clinical examination and radiological analysis of the frontal and sagittal plane preoperatively, postoperatively and at follow-up (2-4 years). Pedicle screws were used at the lumbar and thoracolumbar spine exclusively. RESULTS: The preoperative average Cobb angle was 61.4 degrees with an average flexibility of 36.8% to 38.8 degrees. The average postoperative Cobb angle was 24.8 degrees (59.6%) with an average loss of correction of 2.6 degrees Cobb angle (3.6%). Due to the use of thoracolumbar and lumbar pedicle screws instrumented fusion could be stopped at the lower endvertebra in 71%. Patients in whom only pedicle screws had been used improved correction of frontal plane could be shown compared to combined instrumentations with hooks and screws. CONCLUSION: The posterior instrumentation guarantees primary stability with good results of correction and allows brace free treatment postoperatively. The postoperative correction compared to the results at follow-up proves the stability of the instrumentation largely. The results of mainly pedicle screw based instrumentations verify that an improved correction can be achieved. In most cases fusion levels end at the lower end vertebra and therefore are shorter compared to instrumentation's based on hooks only.     

Is sacral instrumentation mandatory to address pelvic obliquity in neuromuscular thoracolumbar scoliosis due to myelomeningocele?

STUDY DESIGN: Prospective study. OBJECTIVE: To evaluate the functional outcome of two-stage anterior and posterior instrumented fusion without fixation to the sacrum on 11 patients with neuromuscular scoliosis from thoracolumbar myelomeningocele. SUMMARY OF BACKGROUND DATA: To our knowledge, there are no published results of combined anterior and posterior correction and fusion without inclusion of the sacrum in neuromuscular scoliosis from thoracolumbar myelomeningocele. In this article we present our experience and critically evaluate the functional outcome on 11 patients with neuromuscular scoliosis. PATIENTS AND METHODS: From July 1, 1992 through June 30, 1995, 11 consecutive patients with severe thoracolumbar scoliosis were admitted at our hospital. The mean age at operation was 12 years 9 months (range 9 years 9 months to 14 years 6 months). All patients underwent a two-stage anterior and posterior spinal reconstruction. The patients were evaluated before surgery and after surgery. RESULTS: All patients were observed for a mean of 4 years 11 months (range 42-88 months) from the time of second stage procedure. Before treatment the mean scoliosis was 81 degrees (range 55-110 degrees ); this was reduced to a mean of 31 degrees (range 8-70 degrees ), and at the final follow-up the correction had deteriorated slightly to a mean of 35 degrees (range 12-80 degrees ). No patient had increased neurologic deficit or showed other major complication. CONCLUSIONS: Pelvic obliquity in thoracolumbar neuromuscular scoliosis from lumbosacral myelomeningocele spontaneously corrected when the scoliotic deformity is adequately addressed with instrumented fusion without inclusion of the sacrum. The correction obtained remained stable at follow-up. In the absence of a control group we believe that sparing lumbar segments from primary fusion offers these patients a better freedom of mobility.     

Mesh cages in idiopathic scoliosis in adolescents.

Since 1995, titanium mesh cages have been used in the thoracolumbar and lumbar spine for instrumented anterior spinal fusions in adolescents with idiopathic scoliosis. One hundred thirty patients had 451 fusion levels with cages. Radiographic results show acceptable coronal correction with maintained or improved thoracolumbar and lumbar lordotic sagittal alignment. The pseudarthrosis rate has been 3% per patient (four of 130 patients) and 0.08% per fusion level with a cage (four of 451 levels). The authors think that the use of titanium mesh cages anteriorly with single or dual rod anterior instrumentation systems provide for adequate lordotic sagittal alignment and an acceptable pseudarthrosis rate.