External wire-frame fixation of digital skin grafts: A non-invasive alternative to the K-wire insertion method

Background and Aim

The current skin graft fixation methods for digits, including the Kirschner wire insertion technique, can be limited by inadequate or excessive fixation and complications such as infection or secondary injuries. Therefore, the external wire-frame fixation method was invented and used for skin grafting of digits. This study aimed to investigate external wire-frame fixation of digital skin grafts as a non-invasive alternative to the K-wire insertion method.

Methods

In 2005–2012, 15 patients with burn scar contractures on the hand digits received a skin graft that was then fixed with an external wire frame. The intra-operative time needed to make the wire frame, the postoperative time to frame and suture removal, the graft survival rate, the effect of contracture release and the complications were recorded.

Results

In all cases, the contracture release was 100%. The complete graft survival rate was 98.6%. Four patients had epithelial necrosis in <5% of the total area. There were no other complications such as pressure ulcer or hypoxia of fingers.

Conclusions

External wire-frame fixation is simple, minimally invasive and a custom-made technique for skin grafting of the fingers. It was designed for its potential benefits and the decreased risk it poses to patients with scar contractures on their fingers. It can be implemented in three phases of grafting, does not affect the epiphyseal line or subsequent finger growth and is suitable for children with multi-digit involvement.     

Efficacy of a sclerostin antibody compared to a low dose of PTH on metaphyseal bone healing

We compared the effect of a sclerostin antibody to that of a clinically relevant dose of parathyroid hormone (PTH) in a rat model for metaphyseal bone healing. Screws of steel or poly methyl methacrylate (PMMA) were inserted bilaterally into the proximal tibia of young male rats. During 4 weeks the animals then received injections of either phosphate buffered saline (control), sclerostin antibody (25 mg/kg, twice weekly) or PTH (5 µg/kg, daily). The healing response around the screws was then assessed by mechanical testing and X‐ray microtomography (µCT). To distinguish between effects on healing and general effects on the skeleton, other untraumatized bone sites and serum biomarkers were also assessed. After 4 weeks of treatment, PTH yielded a 48% increase in screw pull‐out force compared to control (p = 0.03), while the antibody had no significant effect. In contrast, the antibody increased femoral cortical and vertebral strength where PTH had no significant effect. µCT showed only slight changes that were statistically significant for the antibody mainly at cortical sites. The results suggest that a relatively low dose of PTH stimulates metaphyseal repair (screw fixation) specifically, whereas the sclerostin antibody has wide‐spread effects, mainly on cortical bone, with less influence on metaphyseal healing. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:471–476, 2014.     

Temporal delimitation of the healing phases via monitoring of fracture callus stiffness in rats

The healing process consists of at least three phases: inflammatory, repair, and remodeling phase. Because callus stiffness correlates with the healing phases, it is suitable for evaluating the fracture healing process. Our aim was to develop a method which allows determination of callus stiffness in vivo, the healing time and the duration of the repair phase. The right femurs of 16 Wistar rats were osteotomized and stabilized with either more rigid or more flexible external fixation. Fixator deformation was measured using strain gauges during gait analysis. The strains were recalculated as the callus stiffness over the time course of healing, and the healing phases were identified based on stiffness thresholds. Our hypothesis was that stabilization with more flexible external fixation prolongs the repair phase, therefore resulting in an extended healing time. Confirming our hypothesis, the duration of the repair phase (rigid: approximately 15 days, flexible: approximately 41 days) and the healing time (rigid: approximately 27 days, flexible: approximately 62 days) were significantly longer for more flexible external fixation. Our method allows the quantitative detection of differences in the healing time and duration of the repair phase without multiple time‐point sacrifices, which reduces the number of animals in experimental studies. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1589–1595, 2014.     

外后侧弧形切口双肌间隙入路治疗胫骨后外侧平台塌陷骨折

 目的 探讨外后侧弧形切口双肌间隙入路治疗胫骨后外侧平台塌陷骨折的临床疗效。方法 回顾性分析 2009年 8月至 2013年 3月,采用外后侧弧形切口双肌间隙入路治疗 32例伴有后外侧劈裂、塌陷的胫骨平台骨折患者资料,男 15例,女 17例;年龄 28~77岁,平均 46.25岁;均为闭合性骨折,均未合并神经及血管损伤;受伤至内固定手术时间为 3~ 18 d,平均 7.13 d。通过外后侧入路在胫前肌、腘肌和比目鱼肌间隙两个间隙分别显露胫骨前外侧髁及后外侧髁,在直视下复位骨折,分别用“高尔夫”与“T”形锁定钢板固定胫骨前外侧和后外侧骨折。术后按 Rasmussen 评分评价胫骨平台骨折复位情况,按美国特种外科医院（hospital for special surgery, HSS）评分评价膝关节功能。结果 32例患者均获得随访,随访时间 6~36个月,平均 15.3个月。术后 X线片均示骨折复位良好,关节面未见明显塌陷。骨折全部愈合,愈合时间 6~ 14周,平均 11.2周。末次随访时,Rasmussen评分为 6~18分,平均 14.06分,其中优 14例,良 15例,可 3例,优良率为 90.62%（29/32）。HSS评分为 57~92分,平均 78.25分,其中优 11例,良 17例,可 3例,差 1例,优良率为 87.5%（28/32）。无一例发生腓总神经损伤及重要血管、神经损伤、手术区皮肤坏死、感染或内固定松动。结论 胫骨平台后外侧塌陷骨折采用外后侧弧形切口双肌间隙入路治疗,在一个切口内既可显露胫骨前外侧平台骨折又可兼顾后外侧塌陷骨折,无须腓骨小头截骨,创伤小,切口间皮瓣坏死及钢板外露的发生率低,是一个值得推广的入路。     

可调式锁定接骨板治疗桡骨远端骨折畸形愈合

 目的 探讨可调式锁定接骨板治疗桡骨远端骨折畸形愈合的临床疗效。方法 回顾性分析 2010 年 5 月至2012年 3月,采用可调式锁定接骨板治疗 11例骨折畸形愈合患者资料,男 3例,女 8例;年龄 35～76岁,平均（62.5±12.3）岁;左侧 4 例,右侧 7 例。其中 2 例为夹板固定治疗后致畸形愈合,2 例为石膏固定治疗后致畸形愈合,1 例为外固定治疗后致畸形愈合,6 例为切开复位钢板内固定治疗后致畸形愈合;初次手术至再手术时间为 5～20 个月,平均（13.9±5.6）个月。根据影像学（包括尺骨变异、掌倾角、尺偏角）表现及握力、腕关节关节活动度、疼痛视觉模拟评分（visual analogue scale, VAS）、上肢功能（disability of arm shoulder and hand, DASH）调查表评价术后疗效。结果 11 例患者均获得完整随访,随访时间 10～15 个月,平均 12 个月;影像学骨折愈合时间为 7～12 周,平均 8 周。术后 12 个月腕关节屈曲活动度为 50.2°± 11.3°（范围,35°～70°）,背伸为 55.1°±11.5°（范围,30°～80°）,尺偏为 30.1°±9.2°（范围,10°～40°）,桡偏为 22.1°±6.6°（范围,10°～30°）,旋前为 79.9°±8.5°（范围,60°～90°）,旋后为 82.6°±11.2°（范围,50°～90°）;术后 12个月 DASH评分为平均（18.5±8.3）分（范围,10～35 分）,较术前平均（52.7±11.3）分有明显改善;术后 VAS 评分为平均（1.7±1.2）分（范围,0～4 分）,较术前平均（5.9±1.4）分明显改善。2 例患者术后腕关节功能轻度受限,其中 1 例患者在重体力工作时有中度疼痛,但在内固定取出后症状改善;另 1 例患者经消炎镇痛药物治疗后症状改善。无一例发生继发移位、内置物松动及软组织感染。 结论 可调式锁定接骨板作为一种全新的钢板可以用于治疗桡骨远端骨折畸形愈合,术后患者腕关节解剖结构得以重建,关节功能获得改善。     

Multiaxial high-modularity spinopelvis (HMSP) fixation device in neuromuscular scoliosis: a comparative study

Purpose

To compare radiological and clinical results in patients operated for neuromuscular scoliosis with pelvic fixation using high-modularity spinopelvic screw (HMSP) designed by authors.

Methods

Of 54 patients with neuromuscular scoliosis, group 1 comprised of 27 patients with conventional pelvic fixation; and group 2 comprised of 27 patients using HMSP. Results were evaluated radiologically and functionally. We compared preoperative and postoperative complications, especially the loosening or breakage of spinopelvis fixation device, failure of fixation, and the change of shadow around the spinopelvis fixation device.

Results

There was no difference of correctional power, preoperative average Cobb’s angle of each group was 79.8 and 75 to postoperative 30.2 and 28.3 (P < 0.05). Pelvic obliquity improved from average 18.3°–8.9° in group I and average 24.3°–12.5° in group II (P < 0.05). However, there was no difference between two groups (P > 0.05). Average blood loss was 2,698 ml in group 1 and 2,414.8 ml in group 2 (P > 0.05). Average operative time was 360 min in group 1 and 332 min in group 2 (P = 0.30). There was no difference found between two groups regarding gait and functional evaluation. On the all cases of group 1 and 2, the change of shadow around the spinopelvis fixation device was observed. There was one case of the fracture of spinopelvis fixation device in group I.

Conclusion

There was no difference of Cobb’s angle and correctional power between the groups using HMSP when compared with the group using standard spinopelvis fixation device. Therefore, HMSP can be used more effectively in case of neuromuscular scoliosis.     

Biomechanical advantage of C1 pedicle screws over C1 lateral mass screws: a cadaveric study

Purpose

The established technique for posterior C1 screw placement is via the lateral mass. Use of C1 monocortical pedicle screws is an emerging technique which utilizes the bone of the posterior arch while avoiding the paravertebral venous plexus and the C2 nerve root. This study compared the relative biomechanical fixation strengths of C1 pedicle screws with C1 lateral mass screws.

Methods

Nine human C1 vertebrae were instrumented with one lateral mass screw and one pedicle screw. The specimens were subjected to sinusoidal, cyclic (0.5 Hz) fatigue loading. Peak compressive and tensile forces started from ±25 N and constantly increased by 0.05 N every cycle. Testing was stopped at 5 mm displacement. Cycles to failure, displacement, and initial and end stiffness were measured. Finally, CT scans were taken and the removal torque measured.

Results

The pedicle screw technique consistently and significantly outperformed the lateral mass technique in cycles to failure (1,083 ± 166 vs. 689 ± 240 cycles), initial stiffness (24.6 ± 3.9 vs. 19.9 ± 3.2 N/mm), end stiffness (16.6 ± 2.7 vs. 11.6 ± 3.6 N/mm) and removal torque (0.70 ± 0.78 vs. 0.13 ± 0.09 N m). Only 33 % of pedicle screws were loose after testing compared to 100 % of lateral mass screws.

Conclusions

C1 pedicle screws were able to withstand higher toggle forces than lateral mass screws while maintaining a higher stiffness throughout and after testing. From a biomechanical point of view, the clinical use of pedicle screws in C1 is a promising alternative to lateral mass screws.     

The application of a zero-profile implant in anterior cervical discectomy and fusion

We analyzed the clinical efficacy of the Zero-P implant (Synthes GmbH Switzerland, Oberdorf, Switzerland) in the treatment of single level cervical spondylotic myelopathy. The clinical data of 47 patients with single level cervical spondylotic myelopathy were retrospectively analyzed. Twenty-two patients were treated with a Zero-P implant (Group A) and 25 with a titanium plate with cage (Group B) between January 2009 and September 2010. Operative time, intraoperative blood loss, preoperative and postoperative Japanese Orthopaedic Association (JOA) scores and JOA recovery rate, dysphagia incidence and adjacent segment degeneration rate were measured. The mean operative time in Group A and Group B was 98.18 minutes and 105.4 minutes, respectively. The average intraoperative blood loss in Group A and Group B was 87.95 ml and 92.4 ml, respectively. There were no statistical differences in operation time and intraoperative blood loss between the two groups (p > 0.05). The JOA score was significantly improved in the two groups (p < 0.001), and the recovery rate was similar (60.86% for Group A versus 62.95% for Group B, p > 0.05). Dysphagia was experienced by one (4.5%) patient in Group A and eight (32%) patients in Group B, which was significantly different (p = 0.044). There was no statistical significance found in the adjacent level degeneration rates between Group A and Group B (p = 0.330). The Zero-P implant and traditional titanium plate with cage are effective treatments for single level cervical spondylotic myelopathy, but the Zero-P implant has a lower dysphagia incidence.