Investigation of validity of model for estimating shear force applied to buttocks in elderly people with kyphosis while sitting comfortably on a chair

Purpose.?The purpose of the present study was to investigate the validity of a model for estimating shear force on the buttocks of elderly people with kyphosis.

Method.?The subjects with kyphosis were 10 elderly people in a facility providing health care services for the elderly. The shear force was measured using a force plate and, simultaneously, the position of the resultant centre of mass of the upper body and the inclination angle of the trunk were measured. The estimated shear force was calculated by substituting these values in the model.

Results.?The average value of the measured shear force was 8.4 SD 1.4 [%BW], and the average value of the estimated shear force was 5.8 SD 1.0 [%BW]. Although there was a significant difference between these two values (p?<?0.01), there was a strong positive correlation between them (r?=?0.786, p?<?0.01). The regression line between the two values was y?=?1.097x + 1.96, where x?=?estimated value, y?=?measured value.

Conclusions.?These results suggest that the estimated shear force was close to the measured shear force and thus is approximately known by substituting the calculated values for the linear regression.     

单纯后路360度椎管减压并重建治疗伴神经缺损的胸腰段脊柱旋转不稳爆裂骨折

Summary of Background Data Various treatment of neurologically involved unstable thoracolumbar burst fractures have been described, including anterior, posterior and combined anteroposterior surgery. Among these, the combination of anterior and posterior instrumentation provides the most stable reconstruction. However, the use of both approaches on a trauma patient may increase the morbidity. Methods　From March 2005 to January 2007, 6 patients (5 males, 1 females) with thoracolumbar burst fracture in our institution underwent a single stage posterior approach for spinal canal decompression in combination with circumferential reconstruction. The operation technique includes resection of the posterior elements, partial resection of the injured vertebra and disc, reconstruction of the anterior column with Titanium mesh cage, posterior instrumentation with pedicle screws, and posterior spinal fusion. Preoperative and postoperative X-ray films were reviewed and changes of Cobb angle of thoracolumbar spine were documented. Intraoperative, postoperative and general complications were registered. Results　The involved levels were L2 in 1 patient, L1 in 4 patients and T12 in 1 patient. According to the Frankel grading system, 1 patient had complete, 5 patients had incomplete neurologic deficits. The mean follow-up was 21.7±9.1 months (range, 14 to 48 months). The mean operation time was 248 minutes (range, 208-316 minutes), the average volume of intraoperative blood loss was 2453 ml (range, 1800-3480 ml), the average vertebral body height loss at the injured level was 56% (range, 48–70%), and the average Cobb angle in sagittal plane was improved from 39.8° before surgery (range, 34~46°) to 4.8° (range, -2 ~12°) immediately after surgery. Postoperatively, there was an epidural hematoma in one patient. Bony union after stabilization was obtained in all patients, without loosening or breakage of screws. Loss of correction (5°) was seen in 1 patient at the 6th month owing to the subsidence of the Titanium mesh cages into the vertebra. All patients with incomplete neurologic deficits improved at least 1 Frankel grade. Conclusion Single stage posterior vertebra resection in combination with circumferential reconstruction is a new option to manage severe thoracolumbar burst fracture.     

Magnetic resonance imaging study determining cord level and occupancy at thoracolumbar junction in achondroplasia �C A prospective study

Background:

Thoracolumbar (TL) stenosis in achondroplasia is frequently reported, and becomes symptomatic in adulthood. Hence we conducted a prospective study to determine cord level and occupancy at TL junction in symptomatic or asymptomatic achondroplasis patients in comparision to normal population by magnetic resonance imaging (MRI).

Materials and Methods:

Cord level with its occupancy rate and TL kyphosis were measured on MRI and standing radiogram, respectively. We prospectively studied MRI of TL spine in 19 patients (7 males and 12 females) with achondroplasia. All the subjects were randomly selected from our outpatient clinic and divided into two groups: symptomatic and asymptomatic group. Symptomatic group had at least two of the following symptoms: back pain with spasticity and walking difficulty, radicular pain in upper thigh or girdle pain, tingling and numbness in the lower limbs, visible deformity at TL spine and brisk reflexes in lower extremities. Asymptomatic group was selected from those patients who visited in outpatient clinic for consultation of limb lengthening. The third group was taken as control that comprised 11 nonachondroplasia otherwise normal patients (8 males and 3 females) who presented to our outpatient clinic for back pain.

Results:

Results showed spinal cord level was higher in achondroplasia than nonachondroplasia (P=0.003); however, no difference in cord level between symptomatic and asymptomatic group (P=0.568). Comparing cord occupancy, no difference found among all three groups (P=0.20). Kyphosis was increasing from nonachondroplasia, asymptomatic and symptomatic patient groups (P<0.001). Average age was 22.4±14.2, 11.9±6.5, and 36.2±13.2 years in symptomatic, asymptomatic, and nonachondroplasia groups, respectively (P<0.001).

Conclusion:

Our results indicated high level of spinal cord in achondroplasia patients compared to nonachondroplasia individuals. High prevalence of neurological symptoms at TL level in such patients can be associated with high cord level and developing progressive kyphosis at TL level along with degenerative process.     

强直性脊柱炎胸腰椎后凸畸形经椎弓根椎体截骨术后机械并发症与GAP评分的相关性及其危险因素分析

目的 ：探讨强直性脊柱炎(ankylosing spondylitis,AS)胸腰椎后凸畸形经椎弓根椎体截骨术(pedicle subtraction osteotomy,PSO)术后机械并发症与GAP(global alignment and proportion)评分的相关性,并分析其危险因素。方法：回顾性分析2010年1月～2019年6月在我院行单节段PSO且随访超过2年的AS胸腰椎后凸畸形患者。在术前、术后站立位全脊柱侧位X线片上测量矢状面平衡(sagittal vertical axis,SVA)、骨盆投射角(pelvic incidence,PI)、骶骨倾斜角(sacral slope,SS)、腰椎前凸角(lumbar lordosis,LL)、下腰椎前凸角(lower lumbar lordosis,LLL)、整体倾斜(global tilt,GT),计算GAP评分。根据患者GAP评分分为3组：矢状面协调组(GAP评分0～2分)、中等不协调组(GAP评分3～6分)、严重不协调组(GAP评分7～13分),记录随访过程中发生的机械并发症,包括近端交界性后凸/失败(proxim...     

Lumbar kyphosis in Hunter''s disease (MPS II)

Although radiological involvement of the lower dorsal and upper lumbar vertebrae is common in the severe form of Hunter's disease (MPS II), there are reports in the literature that clinical kyphosis does not occur. We report a boy with marked clinical kyphosis in whom the diagnosis of MPS II was proved by demonstrating a severe deficiency of serum and leucocyte iduronate-sulphate sulphatase and an accelerated incorporation of radiosulphate into his cultured fibroblast glycosaminoglycans, which could not be corrected by the product of other typed reference MPS II cells. The existence of several other genetic diseases, sometimes complicated by kyphosis, was excluded by assay of fibroblast lysosomal enzymes.     

颈前路经椎间隙后缘截骨治疗退变性僵硬型颈椎后凸畸形

目的 总结颈前路经椎间隙后缘截骨（anterior trans-intervertebral osteotomy,ATIVO）技术治疗退变性僵硬型颈椎后凸畸形的治疗策略、方法及临床疗效。方法 回顾性分析2012年至2016年共47例因退变性僵硬型颈椎后凸畸形采用ATIVO技术进行畸形矫形的病例。其中,男性29例,女性18,年龄38~73岁。共83节段进行颈前路经椎间隙后缘截骨（C3/4 16例;C4/5 24例;C5/6 25例;C6/7 16例;C7/T1 2例）。单节段17例,双节段24例（跳跃节段6例）,3节段6例。经颈前路经椎间隙进行截骨,切除椎间盘及后纵韧带,两侧切除部分钩椎关节并进行松解,椎体后缘截骨面潜行约10°~15°,至少保留2/3终板。术中使用椎间撑开器、带角度椎间融合器、调整颈下软枕及改变颈后伸角度等综合方式进行后凸畸形矫形。融合方式采用填充人工骨颗粒的椎间融合器,固定方式采用自锁式椎间融合器或前路钛板。应用脊柱显微镜、脊柱骨动力系统（气动磨钻）进行截骨操作。应用皮节体感诱发电位、运动诱发电位、自由肌电进行联合功能监测。手术前后通过X线、CT进行影像学评估C2-C7 Cobb角、颈椎矢状面垂直轴（cervical sagittal vertical axis,cSVA）及截骨效果。使用疼痛视觉模拟评分（Visual Analogue Score,VAS）,颈椎功能障碍指数（Neck Disability Index,NDI）,日本骨科协会改良颈椎评分（modified Japanese Orthopaedic Association Score,mJOA）对临床疗效进行评价。结果 47例患者均获得最少1年随访,平均随访时间20个月（12个月至5年）。平均手术时间109 min （55~140 min）、出血量46 mL （25~110 mL）。术后3例患者出现肩部疼痛,5例患者出现C5神经根麻痹症状,无椎动脉损伤病例。末次随访时VAS、NDI、mJOA分别由术前7.2±1.5、64.5±17.4、10.5±0.9改善至2.6±1.7、34.8±21.6、14.5±1.3。CT显示截骨节段均获融合。C2-C7 Cobb角由13.6°±5.1°改变为-7.4°±3.6°;截骨节段矫形能力7.4°（5.3°~9.6°）/节段;C2-C7矢状面垂直轴由（55.7±13.8） mm改变为（31.4±8.2） mm。结论 采用颈前路经椎间隙后缘截骨技术治疗退变性僵硬性后凸畸形可获得良好的疗效,可显著纠正颈椎后凸畸形,纠正整体颈椎曲度,并阻止颈椎向前的矢状位失平衡趋势。该截骨技术骨量损失小,不影响椎间融合率,可多节段联合应用提高矫形效果。适用于由椎间盘、钩椎关节等原因导致的颈椎僵硬性后凸畸形。     

经椎弓根楔形截骨术治疗强直性脊柱炎驼背畸形

目的：评价１７ 例强直性脊柱炎所致驼背畸形采用经椎弓根楔形截骨术矫形效果。方法： 截骨从胸腰椎后柱一处或二处楔形切去一高约３ｃ ｍ 的骨块,去除两则的椎弓根,去除椎体松质骨的后２／３ 部分,闭合截骨处,器械内固定。术后随访１ ～４ 年, 平均２５ 年。结果：１７ 例术后均改善了外观, 畸形矫正满意。结论：经椎弓根楔形截骨术治疗强直性脊柱炎所致驼背畸形是一种疗效可靠满意的手术方法。     

脊柱后凸全脊椎截骨术后矫正度丢失原因分析

目的　分析强直性脊柱炎后凸畸形全脊椎截骨矫正术后矫正度丢失原因 ,提出预防方法。方法　对 95例行全脊椎截骨矫正的强直性脊柱炎后凸畸形患者进行平均 5年 6个月的随访 ,将术前、术后及随诊的X线片对比 ,分析矫正度丢失与疾病阶段、手术矫正程度、内外固定方法等多因素的关系。结果　矫正度丢失 <5°者 34例 ,丢失 6°～ 10°者 19例 ,丢失 11°～ 15°者 2 4例 ,丢失 16°～ 2 0°者 16例 ,丢失 >2 1°者 2例 (平均 12 .2°)。结论　为防止矫正度丢失 ,手术应在强直性脊柱炎病情稳定后进行 ,尽量恢复身体轴线 ,加强内外固定的可靠性 ,注意围手术期的护理。     

椎弓椎体楔形截骨治疗腰椎后凸伴不全瘫

目的　观察经椎弓椎体楔形截骨治疗L1～ 3 后凸畸形伴不全瘫的疗效。方法　经椎弓椎体楔形截骨 ,行椎弓根螺钉加短Luque棒或Dick钉内固定。结果　平均随访 18个月 ,后凸角平均纠正42°。Frankel评分进步 1～ 2级 ,截骨处愈合。结论　该方法治疗L1～ 3 后凸畸形伴不全瘫 ,效果良好 ,但手术时间长 ,出血量大 ,易出现脊髓及大血管损伤 ,宜掌握好适应证。