Complications associated with thoracic pedicle screws in spinal deformity

Thoracic pedicle screws have superior anchoring strength compared with other available fixation techniques. However, these are not universally accepted in many developing countries because of the concerns regarding safety and complications. In addition, there is evidence that pedicle morphology is unique in Chinese patients. The goal of this study was to analyze the complications seen at our institution, while using thoracic pedicle screws for the treatment of thoracic deformity, and to determine the safety of our techniques for the treatment of thoracic deformity in a Chinese population. From 1998 to 2005, there were 208 thoracic deformity patients treated at our institution, 70 of whom were male and 138 were female. Their age ranged from 11 to 55 years (mean of 14.9 years). All of them underwent corrective deformity surgery using posterior pedicle screw systems and follow-up was available for at least 3 years. Etiologic diagnoses included adolescent idiopathic scoliosis in 119 patients, congenital kyphoscoliosis in 38, adult scoliosis in 37 and undetermined in 14. Screw positions were evaluated using intraoperative and postoperative radiographs and a CT scan was performed when a concern for screw malposition was present. All radiographic evaluations were carried out in a double-blinded fashion. A total of 1,123 thoracic pedicle screws were inserted (5.4 thoracic screws/patient). The deformity correction rate was 81, 65 and 62% for idiopathic, congenital and adult scoliosis patients, respectively. The overall complication rate was 16.5% at the final follow-up. Complication rates directly and indirectly related to pedicle screws were 7.2 and 9.3%, respectively. There were no significant screw-related neurologic or visceral complications that adversely affected long-term results. The complications seen with thoracic pedicle screws in a Chinese population were similar to other populations and could be utilized safely for the treatment of thoracic deformity in this population.     

Effect of lumbar angular motion on central canal diameter: positional MRI study in 491 cases

Background Lumbar spinal stenosis is a common problem that is receiving attention with the advent of novel treatment procedures. Prior positional MRI studies demonstrated lumbar canal diameter changes with flexion and extension. There have not been any studies to examine the amount of spinal canal diameter change relative to the amount of angular motion. The purpose of this study was to evaluate the correlation between the lumbar canal diameter change and the angular motion quantitatively. Methods Positional MRI （pMRI） images for 491 patients, including 310 males and 181 females （16 years-85 years of age）, were obtained with the subjects in sitting flexion 40 degree, upright, and with extension of 10 degrees within a 0.6 T Positional MRI scanner. Quantitative measurements of the canal diameter and segmental angle of each level in the sagittal midline plane were obtained for each position. Then the diameter change and angular motion were examined for correlation during flexion and extension with linear regression analysis. Results The lumbar segmental angles were lordotic in all positions except L1-2 in flexion. The changes of canal diameters were statistically correlated with the segmental angular motions during flexion and extension （P 〈0.001）. The amount of canal diameter change correlated with the amount of angular change and was expressed as a ratio. Conclusions Positional MRI demonstrated the amount of spinal canal diameter change that was statistically correlated with the segmental angular motion of the spine during flexion and extension. These results may be used to predict the extent of canal diameter change when interspinous devices or positional changes are used to treat spinal stenosis and the amount of increased canal space may be predicted with the amount of angular or positional change of the spine. This may correlate with symptomatic relief and allow for improved success in the treatment of spinal stenosis.     

肩袖钙化性肌腱炎的关节镜治疗

目的探讨关节镜下钙化灶清理术治疗肩袖钙化性肌腱炎的手术方法和临床效果。方法2003～2006年对14例肩袖钙化性肌腱炎患者行关节镜下钙化灶清理术。男1例,女13例,平均年龄46.1岁。左肩5例,右肩9例,涉及优势侧9例。术前均拍摄肩关节正位和冈上肌出口位X线片,8例行B超检查,8例行MRI检查。全部患者均行关节镜下钙化灶清理术,4例行肩峰成形术,6例行肩袖修复术。分别在术前和最终随访时采用UCLA肩关节评分标准进行评价。结果随访时间1～5年,平均32个月,手术前、后平均UCLA评分分别为(13.3±3.9)和(32.0±2.9)分,差异有统计学意义(t=-12.486,P0.01)。其中疼痛评分平均为(2.3±0.7)和(8.7±1.3)分(t=-17.198,P0.01),功能评分平均为(4.0±1.6)和(8.7±1.5)分(t=-6.600,P0.01),肩关节主动前屈评分平均为(3.1±1.8)和(4.9±0.3)分(t=-3.617,P0.01),前屈肌力评分平均为(3.9±0.5)和(4.6±0.5)分(t=-5.078,P0.01),优7例,良7例。所有患者均对手术效果表示满意。结论关节镜下钙化灶清理术有许多优点,是治疗肩袖钙化性肌腱炎的有效方法。     

Comparison of Osteogenic Potentials of BMP4 Transduced Stem Cells from Autologous Bone Marrow and Fat Tissue in a Rabbit Model of Calvarial Defects

We compared bone marrow stem cells (BMSCs) and adipose-derived stem cells (ADSCs) of adult rabbits under identical conditions in terms of their culture characteristics, proliferation capacity, osteogenic differentiation potentials induced by adenovirus-containing bone morphogenetic protein 4 (Ad-BMP4) in vitro, and capacity to repair calvarial defects in the rabbit model by autologous transplantation ex vivo. According to the results of growth curve, cell cycle, and telomerase activity analysis, ADSCs possess a higher proliferation potential. Both of the Ad-BMP4 transduced MSCs expressed BMP4 mRNA and protein and underwent osteogenic differentiation. Up-regulated mRNA expression of all osteogenic genes was observed in differentiated BMSCs and ADSCs, but with different patterns confirmed by real-time RT-PCR. Deposition of calcified extracellular matrix was significantly greater in differentiated ADSCs compared with differentiated BMSCs. X-ray and histological examination indicated significant bone regeneration in the calvarial defects transplanted with Ad-BMP4 transduced autologous MSCs compared to the control groups. There was no significant difference in new bone formation in Ad-BMP4 transduced MSCs based on quantitative digital analysis of histological sections. The use of ADSCs often resulted in the growth of fat tissue structures in the control groups, and the fat tissue structures were not seen with BMSC cells. Our data demonstrate that BMP4 can be potently osteoinductive in vivo, resulting in bone repair. ADSCs may be an attractive alternative to BMSCs for bone tissue engineering under appropriate stimuli. But the easy adipogenic differentiation needs to be considered when choosing adipose tissue for specific clinical application.     

Electroformed iron as new biomaterial for degradable stents: Development process and structure–properties relationship

An electroforming technique was developed for fabricating iron foils targeted for application as biodegradable cardiovascular stent material. The microstructure, mechanical properties and corrosion of electroformed iron (E-Fe) foils were evaluated and compared with those of pure iron made by casting and thermomechanical treatment (CTT-Fe), with 316L stainless steel (316L SS) and with other candidate metallic materials for biodegradable stents. Electron backscattered diffraction revealed an average grain size of 4 μm for E-Fe, resulting in a high yield (360 MPa) and ultimate tensile strength (423 MPa) being superior to those of other metallic biodegradable stent materials. Annealing at 550 °C was found to improve the ductility of the E-Fe from 8% to 18%. The corrosion rate of E-Fe in Hanks’ solution, measured by potentiodynamic polarization, was higher than that of CTT-Fe, which had been found to have a slow in vivo degradation. The results showed that E-Fe possesses fine-grain microstructure, suitable mechanical properties and moderate corrosion rate as a degradable stent material.     

(−)-Epigallocatechin-3-gallate induces apoptosis and suppresses proliferation by inhibiting the human Indian Hedgehog pathway in human chondrosarcoma cells

Purpose  

Chondrosarcoma is a soft tissue sarcoma with a poor prognosis that is unresponsive to conventional chemotherapy. The regulatory mechanisms for the rapid proliferation of chondrosarcoma cells and the particular aggressiveness of this sarcoma remain poorly understood. In this study, we investigate the effect of epigallocatechin-3-gallate (EGCG) on growth and apoptosis of chondrosarcoma cells.     

Quantification of mobility impairment and self-assessment of stiffness in patients with myotonia congenita by the physiotherapist

We investigated test-retest reliability and responsiveness in two functional measuring instruments, Timed Up&Go (TUG) and Timed-Stands Test (TST), and in three self-assessment scales, Visual Analogue Scale (VAS), Borg's Category-Ratio Scale (BorgCR10) and Myotonia Behaviour Scale (MBS) when quantifying myotonic stiffness and mobility impairment. These methods were used in the assessment of treatment efficacy of mexiletine. Six male patients with myotonia congenita followed a standardised protocol with time scoring and rest on two occasions, with and without mexiletine. Time scoring of TUG and TST and self-assessments of stiffness were performed. A 14-day stiffness diary was used at home. Timed Up&Go and TST showed very good test-retest agreement (ICC=0.87-0.95) and significant to change (P=0.005 and 0.001, respectively). All self-assessment scales revealed excellent responsiveness and good test-retest reliability. The measurement instruments possess great capacity to detect functional impairment in the myotonia congenita patient group, and sensibility to identify true changes due to treatment. When considering the results, three instruments are favoured; Timed Up&Go and BorgCR10 for short, and MBS for long-term evaluations.     

Risk factors for implant failure of intertrochanteric fractures with lateral femoral wall fracture after intramedullary nail fixation

IntroductionFew studies have specifically evaluated the comminution extent of lateral femoral wall (LFW) fracture and risk factors of implant failure in intertrochanteric fractures with LFW fracture. The aim of present study was to evaluate the influence of comminution extent of LFW fracture on implant failure and identify risk factors of implant failure in cases with LFW fracture after intramedullary fixation.MethodsThis retrospective study included 130 intertrochanteric fracture with LFW fracture treated with intramedullary fixation at a teaching hospital over a 13-year period from January 2006 to December 2018. Demographic information, cortical thickness index, the reduction quality, status of medial support, position of the screw/blade and status of lateral femoral wall were collected and compared. The logistic regression analyzes was performed to evaluate risk factors of implant failure in intertrochanteric fractures with LFW fracture after intramedullary nail fixation.Results10 patients (7.69%) suffered from mechanical failure after intramedullary fixation. Univariate analyzes showed that comminuted LFW fracture (OR, 7.625; 95%CI, 1.437~40.446; p = 0.017), poor reduction quality (OR, 49.375; 95%CI, 7.217~337.804; p < 0.001) and loss of medial support (OR, 17.818; 95%CI, 3.537~89.768; p < 0.001) were associated with implant failure. After adjustment for confounding variables, the multivariable logistic regression analyzes showed that poor reduction quality (OR, 11.318; 95%CI, 1.126~113.755; p = 0.039) and loss of medial support (OR, 7.734; 95%CI, 1.062~56.327; p = 0.043) were independent risk factors for implant failure. Whereas, comminuted LFW fracture was not associated with implant failure (p = 0.429).ConclusionsThe comminution extent of the LFW fracture might influence the stability of intertrochanteric fractures; and intramedullary fixation might be an effective treatment method. Furthermore, poor reduction quality and loss of medial support could increaze the risk of implant failure in intertrochanteric fractures with LFW fractures after intramedullary fixation. Therefore, we should pay great emphasis on fracture reduction quality in future.     

Use of intra-rectal ultrasound with color Doppler and Doppler flow analysis in differentiation of benign and malignant rectal disease

Objective: Assessment of the efficacy of intra-rectal ultrasound with color Doppler and Doppler flow analysis in detecting possible differences in blood flow patterns between malignant and benign rectal diseases. Subjects and methods: During a period of 12 months, 28 consecutive patients with benign (9 patients) and malignant (19 patients) rectal and perirectal diseases were prospectively evaluated with intra-rectal gray scale and color Doppler ultrasound and Doppler flow analysis. Results: Color Doppler flow showed hypervascularity in 4 of the 9 patients (44%) with benign disease and in 17 of 19 cases with carcinoma (89%). In 24 patients a Doppler flow spectrum could be assessed. The mean resistance index (RI) for the group with rectal carcinoma (n = 19) was 0.78 ranging from 0.56 to 1 and was significantly different (P < 0.005) from that of the group with benign diseases (n = 5, mean RI 0.58, ranging from 0.43 to 0.7). Conclusions: This preliminary work suggests that color Doppler and Doppler flow analysis may have value in differentiating malignant from benign rectal disease; however, considerable overlap in RI data exists.     

椎间融合器高度对颈椎生物力学影响

目的研究颈椎前路减压融合术中椎间融合器高度对颈椎生物力学影响,为融合器选择提供参考。方法建立正常颈椎C2~7节段有限元模型并验证,在C5~6节段分别植入高度为5、6、7、8 mm的融合器,施加1.5 N·m力矩使颈椎产生前屈、后伸、侧弯和轴向旋转运动,并探究融合器高度变化对颈椎活动度(range of motion,ROM)、小关节应力、椎间压强等的影响。结果融合器高度每增加1 mm,手术节段的角度值平均增加0.68°。植入融合器后C5~6 ROM范围小于0.44°。融合器高度差异对C4~5的ROM影响大于C6~7,对非融合节段ROM的影响小于7.3%。融合器高度差异对非手术节段ROM、小关节应力、相邻节段椎间压强的影响较小。关节囊韧带、融合器和钉板系统应力均随融合器高度增加而明显增加,6、7、8 mm融合器模型的关节囊韧带、融合器和钉板系统应力均远高于5 mm融合器模型。结论对于需要植入融合器的患者,建议植入物高度比原椎间隙高0~1 mm。