Biomechanical analysis of a novel Y-plate designed for the treatment of extraarticular distal humerus fractures

Adult distal humerus fractures are infrequent, yet they account for one-third of all humerus fractures. For the treatment of comminuted and osteoporotic fractures, locking plates are claimed to be biomechanically superior to alternative internal fixing techniques. Treatment remains difficult despite recent advancements and the use of locking plates due to frequent comminution, low bone quality, and limited healing ability in osteoporotic bone. An optimal design of the newly constructed plate and the control model were selected. The biomechanical characteristics of non-osteoporotic and osteoporotic synthetic bone were compared on six models. The biomechanical properties of the new plate were tested and compared on 54 osteoporotic synthetic humerus models. The control models were reconstructive and parallel LCPs. The tests were carried out under static and dynamic axial, lateral and bending loads. Fracture displacements were measured by optical measuring system Aramis. The test model is significantly stiffer for lateral load (p = 0.0007) and for bending load at the moment of model failure (p = 0.0002), while for axial load the LCP model showed greater stiffness (p = 0.0017). During lateral dynamic loading, all three LCP models broke and there was a significant difference compared to the test model (p = 0.0125). The LCP model is dynamically significantly more durable under axial load, while the largest displacements were recorded with the test model (p = 0.029). The displacements induced by all three loads are within the limits that fulfil the parameters of appropriate biomechanical stability. A novel locking plate for extra-articular distal humerus fractures may provide an alternative to the traditional two-plate.     

大剂量甲基强的松龙在伴有严重脊髓受压的脊髓型颈椎病围手术期的应用

目的:探讨大剂量甲基强的松龙(methylprednisolone,MP)在伴有严重脊髓受压的脊髓型颈椎病患者围手术期应用的价值。方法:选取有严重脊髓受压的颈椎病患者62例,采用颈前路椎体次全切除减压植骨内固定或后路单开门减压椎管扩大成形术治疗。按照围手术期是否使用MP分为MP治疗组和对照组。MP治疗组38例,术中操作达椎前或后路达椎板时静脉给予MP30mg/kg,15min滴完;45min后给予5.4mg/kg/h维持23h,术后第1～3天均按80mg/次静脉滴注,每天2次;术后第4天停用。对照组24例,施行同样减压术,于手术当时开始常规使用地塞米松(DXM)治疗,10mg/次,每天1次,应用3d。比较两组患者术后1周内脊髓功能JOA评分和相关并发症发生率。结果:术前MP治疗组及对照组患者JOA评分分别为6.9±2.3分和7.5±2.7分,差异无统计学意义(P>0.05)。术后MP治疗组JOA评分为11.9±3.2分,改善率为49.5%;对照组为9.1±2.1分,改善率为16.8%,两组间比较有显著性差异(P<0.01)。消化道溃疡、感染等并发症发生率两组间均无统计学意义(P>0.05)。术后对照组中4例出现症状加重,经对症处理后1例完全恢复,2例肢体仍有麻痛感,1例肌力未完全恢复正常。结论:围手术期大剂量使用MP在伴有严重脊髓压迫的颈椎病患者的减压治疗中具有明显改善神经功能的作用,可有效地预防由于手术所造成的神经刺激症状,相关并发症比较少见。     

Surgical site infection following surgery for spinal deformity: About 102 patients

IntroductionComplex spinal surgery is known to be at risk of complications. Surgical site infection is a serious complication in spine surgery and its frequency is significantly increased in adult spinal deformity correction. The aim of this study is to identify patients’ characteristics and risk factors of surgical site infection (SSI) following an osteotomy.MethodsThis is a single-center retrospective study of patients who underwent an osteotomy between January 2015 and December 2017. Surgical site infection diagnosis was based upon patient's clinical evidence of infection, biologic parameters, microbiological criteria and/or image findings.ResultsIn total, 102 patients were eligible and 70 were women (68.6%). Mean age was 65 years old (27–83 years) and mean body mass index (BMI) was 26.14 kg.m⁻² (18.4–44.1). Eleven patients were in the SSI group and 91 in the No-SSI group. The mean Schwab grade was 1.5 (1–4) in the SSI group vs. 1.4 (1–5) in the No-SSI group (P = 0.435). The mean operative time was on 201.9 minutes (67–377). Mean length of stay was 20.6 days (10–73) in the SSI group vs. 15 days (5–44) in the No-SSI group (P = 0.041). Favorable outcome was found in 10 patients (90.9%) in the SSI group.ConclusionCorrection surgery for adult spinal deformity with osteotomies carries a high risk of complications specially SSI. Identification of risk factors, prevention and medical management of SSI should be well assessed.     

Surgical management of persistent post-traumatic trans-tentorial brain hernia

IntroductionTemporal engagement may persist after etiologic surgical treatment of acute subdural hematoma (ASH) without clinical improvement despite normalized intracranial pressure (ICP). The aim of this study was to assess the feasibility of secondary direct temporal lobe disengagement (DTLD) after surgery for supratentorial ASH and to evaluate clinical outcome.Materials and methodsThis was a retrospective analysis of 4 patients undergoing secondary DTLD. Patient data were recorded at admission, pre- and postoperatively and at 6 months’ follow-up (FU): age, gender, Rotterdam score, Glasgow Coma Scale (GCS), neurological deficits, oculomotor nerve palsy (ONP), ICP, midline shift, complications and Extended Glasgow Outcome Scale (GOS-E).ResultsAt postoperative evaluation 48 h after DTLD, we observed a significant improvement in GCS score (initial 6 ± 3, preoperative 7 ± 3, postoperative 14 ± 1; P = 0.02), midline shift (initial 16 ± 3 mm, preoperative 13 ± 5 mm, postoperative 9 ± 2 mm; P = 0.049) and ONP (P = 0.01). In all cases, early postoperative imaging documented visualization of a patent ipsilateral peri-mesencephalic cistern. At 6-month FU, GOS-E showed 75% good recovery and 25% disability. Complete ONP recovery was observed in 75% of patients (P = 0.01). Neurological deficits were present at FU in 25% of patients. No surgery-related complications or mortality were recorded.ConclusionsIn traumatic brain injury, secondary DTLD may allow simple, effective and safe management of trans-tentorial uncal herniation, avoiding more challenging procedures. Clinical results are promising, as this technique seems to favorably influence neurological outcome in this selected subgroup of patients with persistent clinical and radiological signs of temporal engagement after etiological treatment with normal ICP values.     

The use of triangular implants to enhance sacropelvic fixation: a finite element investigation

Background contextLong thoracolumbar fixation and fusion have become a consolidated treatment for severe spinal disorders. Concomitant sacropelvic fixation with S2 alar-iliac (S2AI) screws is frequently performed to limit instrumentation failure and pseudarthrosis at the lumbosacral junction.PurposeThis study explored the use of triangular titanium implants in different configurations in which the implants supplemented standard sacropelvic fixation with S2AI screws in order to further increase the stability of S2AI fixation.Study designFinite element study.MethodsFour T10-pelvis instrumented models were built: pedicle screws and rods in T10–S1 (PED); pedicle screws and rods in T10–S1, and bilateral S2 alar-iliac screws (S2AI); pedicle screws and rods in T10–S1, bilateral S2AI screws, and triangular implants inserted bilaterally in a sacral alar-iliac trajectory (Tri-SAI); pedicle screws and rods in T10–S1, bilateral S2AI screws and two bilateral triangular titanium implants inserted in a lateral trajectory (Tri-Lat). The models were tested under pure moments of 7.5 Nm in flexion-extension, lateral bending and axial rotation.RESULTSSIJ motion was reduced by 50% to 66% after S2AI fixation; the addition of triangular titanium implants in either a SAI or a lateral trajectory further reduced it. S2AI, Tri-SAI, and Tri-Lat resulted in significantly lower stresses in S1 pedicle screws when compared to PED. Triangular implants had a protective effect on the maximal stresses in S2AI screws, especially when placed in the SAI trajectory. Sacropelvic fixation did not have any protective effect on the posterior rods.ConclusionsSupplementing S2AI screws with triangular implants had a protective effect on the S2AI screws themselves, as well as the S1 pedicle screws, in the tested model.Clinical significanceTriangular implants can substantially reduce the residual flexibility of the SIJ with respect to S2AI fixation alone, suggesting a possible role in patients needing reinforced fixation. In vivo investigation is needed to determine if these in vitro effects translate into clinically important differences.