Biomechanical comparison of different rod-to-rod connectors to a conventional titanium- and cobalt chromium posterior spinal fixation system.

Introduction: Several types of rod-to-rod connectors are available for the extension of spinal fixation systems. However, scientific literature regarding the mechanical performance of different rod-to-rod connector systems is lacking.

Research Question: The goal of this study was to evaluate the mechanical characteristics of axial and lateral rod connectors in comparison to a conventional pedicle screw rod (titanium and cobalt chromium) construct.

Impact of Obesity on Perioperative Complications on Treatment of Spinal Metastases: A Multicenter Surveillance Study from the German Spine Registry (DWG-Register).

 The spine is a common location for the development of primary and metastatic tumors, spinal metastases being the most common tumor in the spine. Spinal surgery in obesity is challenging due to difficulties with anesthesia, intravenous access, positioning, and physical access during surgery. The objective was to investigate the effect of obesity on perioperative complications by discharge in patients undergoing surgery for spinal metastases.

A Prospective, Randomized Study Evaluating Clinical and Radiographic Efficacy of Lumbar Interbody Fusion Performed Using a Truss Technology-Based Interbody Fusion Device With Homologous Bone or Bone Marrow Aspirate.

Background: Our group used vertebral bone marrow aspirate (BMA) with an anterior truss-based interbody implant to promote fusion. This implant has biomechanical characteristics that may enhance bone on-growth and through-growth and allow for the use of BMA clot alone. The primary end point was comparison of the proportion of patients who achieved fusion with the implant packed with either crushed cancellous homologous bone chips (CCB) alone or with BMA clot alone.

Management of Deep Spinal Wound Infections Following Instrumentation Surgery with Subfascial Negative Pressure Wound Therapy.

Background And Study Aims:  The treatment of infections following a spine surgery continues to be a challenge. Negative pressure wound therapy (NPWT) has been an effective method in the context of infection therapy, and its use has gained popularity in recent decades. This study aims to analyze the impact of known risk factors for postoperative wound infection on the efficiency and length of NPWT therapy until healing.

Intra- and postoperative complications in the treatment of spinal metastases . A multicenter surveillance study from the German Spinal Registry (DWG-Register).

Background: The incidence of spinal column tumors is estimated to be 0.62 per 100,000 individuals in the USA. It is especially important to understand the incidence and predictive factors for adverse events of surgery in spinal oncology patients, as a single complication may be associated with morbidity, mortality, and costs.

Carbon fiber-reinforced pedicle screws reduce artifacts in magnetic resonance imaging of patients with lumbar spondylodesis.

The study investigated whether the use of carbon fiber-reinforced PEEK screw material (CF-PEEK) can reduce magnetic resonance imaging (MRI) artifact formation. Two consecutive groups of patients were treated for degenerative spinal disorders of the lumbar spine with dorsal transpedicular spinal fusion. The first group (n = 27) received titanium pedicle screws.

There is no difference in perioperative results between posterior instrumentation with and without interbody cage and debridement in primary spondylodiscitis in adults: a multicenter surveillance study from the German Spine Registry (DWG Register).

Background: Primary spondylodiscitis is a medically challenging disease that can lead to recurrent back pain, progressive kyphotic deformity, and neurologic deficits. The incidence rate of primary non-tuberculosis spondylodiscitis has been estimated from 2.2 to 2.

Invasiveness has no influence on the rate of incidental durotomies in surgery for multisegmental lumbar spinal canal stenosis (≥3 levels) with and without fusion: analysis from the German Spine Registry data (DWG-Register).

Background: Nowadays, perioperative complications as dural tear (DT) with subsequent neurological deficits are documented in independent registers. However, the relationship of these complications with the grade of invasiveness (≥3 levels) is still unclear. The aim of this study was to evaluate perioperative complications, particularly DT with subsequent neurological deficits, between patients undergoing laminotomy and decompression and decompression and fusion in ≥3 levels.

Clinical Outcome After Anterior Lumbar Interbody Fusion With a New Osteoinductive Bone Substitute Material: A Randomized Clinical Pilot Study.

Study Design: Pilot, single-center, single-blinded, parallel-group, randomized clinical study.

Objective: The aim of this study was to pilot a randomized clinical study to evaluate whether instrumented anterior lumbar interbody fusion (ALIF) with a new nanocrystalline hydroxyapatite embedded in a silica gel matrix (NH-SiO2) leads to superior radiologic and clinical outcomes at 12-month follow-up compared with instrumented ALIF with homologous bone.

Summary Of Background Data: ALIF completed with interbody cages is an established technique for performing arthrodesis of the lumbar spine.

Radiological evaluation of kyphoplasty with an intravertebral expander after osteoporotic vertebral fracture.

Spinal deformities due to osteoporotic vertebral compression fractures can be reduced by balloon kyphoplasty, but the correction may be partly lost when the balloon is deflated. The present study aimed to evaluate an intravertebral expander developed to reduce and maintain vertebral body height while cement is injected to correct spinal deformities due to osteoporotic vertebral fractures. The study included 31 osteoporotic vertebral body fractures in 31 patients, classified as A1 according to the AO classification, who underwent kyphoplasty using an intravertebral expander.

Using the Oxford Foot Model to determine the association between objective measures of foot function and results of the AOFAS Ankle-Hindfoot Scale and the Foot Function Index: a prospective gait analysis study in Germany.

Objective: After cross-cultural adaption for the German translation of the Ankle-Hindfoot Scale of the American Orthopaedic Foot and Ankle Society (AOFAS-AHS) and agreement analysis with the Foot Function Index (FFI-D), the following gait analysis study using the Oxford Foot Model (OFM) was carried out to show which of the two scores better correlates with objective gait dysfunction.

Design And Participants: Results of the AOFAS-AHS and FFI-D, as well as data from three-dimensional gait analysis were collected from 20 patients with mild to severe ankle and hindfoot pathologies.Kinematic and kinetic gait data were correlated with the results of the total AOFAS scale and FFI-D as well as the results of those items representing hindfoot function in the AOFAS-AHS assessment.

Anterior cement augmentation of adjacent levels after vertebral body replacement leads to superior stability of the corpectomy cage under cyclic loading-a biomechanical investigation.

Background: In the operative treatment of osteoporotic vertebral body fractures, a dorsal stabilization in combination with a corpectomy of the fractured vertebral body might be necessary with respect to the fracture morphology, whereby the osteoporotic bone quality may possibly increase the risk of implant failure. To achieve better stability, it is recommended to use cement-augmented screws for dorsal instrumentation. Besides careful end plate preparation, cement augmentation of the adjacent end plates has also been reported to lead to less reduction loss.

Small cavity creation in the vertebral body reduces the rate of cement leakage during vertebroplasty.

Cement leakage is the most common complication during vertebroplasty and may result in serious morbidity. Measures to reduce the rate of cement leakage are valuable ways to improve vertebroplasty safety. The present study aimed to evaluate whether creating a small cavity in the vertebral body prior to cement injection would reduce the rate of cement leakage during vertebroplasty.

PMMA-hydroxyapatite composite material retards fatigue failure of augmented bone compared to augmentation with plain PMMA: in vivo study using a sheep model.

Polymethylmethacrylate (PMMA) is the most commonly used void filler for augmentation of osteoporotic vertebral fracture, but the differing mechanical features of PMMA and osteoporotic bone result in overload and failure of adjacent bone. The aim of this study was to compare fatigue failure of bone after augmentation with PMMA-nanocrystalline hydroxyapatite (HA) composite material or with plain PMMA in a sheep model. After characterization of the mechanical properties of a composite material consisting of PMMA and defined amounts (10, 20, and 30% volume fraction) of HA, the composite material with 30% volume fraction HA was implanted in one distal femur of sheep; plain PMMA was implanted in the other femur.

Nanocrystalline hydroxyapatite facilitates bone apposition to polymethylmethacrylate: histological investigation using a sheep model.

Polymethylmethacrylate (PMMA) is the most commonly used bone void filler for vertebral augmentation in osteoporotic fracture. It provides mechanical stability and immediate pain relief; however, PMMA is not osteointegrated and is separated from the surrounding bone tissue by a thin fibrous layer. The aim of this study was to investigate the effect of nanocrystalline hydroxyapatite (HA) on osteointegration of PMMA in a sheep model.

Changes of femoral periprosthetic bone mineral density 6 years after treatment with alendronate following total hip arthroplasty.

Earlier osteodensitometric results of femoral periprosthetic bone showed that postoperative antiresorptive treatment with alendronate following total hip arthroplasty (THA) reduces the periprosthetic bone loss that commonly occurs in the first months after surgery. However, whether alendronate can prevent periprosthetic bone loss over the long term, or if bone loss occurs after discontinuing alendronate is unknown. Femoral periprosthetic bone mineral density (BMD) was assessed in 49 patients 6 years after cementless total hip arthroplasty using dual energy X-ray absorptiometry.

Alendronate prevents femoral periprosthetic bone loss following total hip arthroplasty: prospective randomized double-blind study.

Following total hip arthroplasty (THA), femoral periprosthetic bone undergoes a remodeling process that results in bone loss in its proximal regions that may compromise the long-term outcome of THA. Periprosthetic bone loss mainly occurs during the first postoperative months. The question is whether a postoperative treatment with alendronate is effective in reducing periprosthetic bone loss and which doses and duration of treatment are required.

Changes of the biochemical markers of bone turnover and periprosthetic bone remodeling after cemented hip arthroplasty.

Do periprosthetic bone loss and postoperative levels of the biochemical markers of bone turnover correlate? The femoral bone mineral density of 53 patients was measured by dual-energy x-ray absorptiometry 1 week and 2, 4, 6, and 12 months after cemented total hip arthroplasty (THA). Biochemical markers of bone turnover were assayed preoperatively and 3, 8, 16, and 24 weeks post-THA. Greatest bone loss was detected in the calcar region (region of interest 7), on average, 16% after 1 year.

Bone strength influences periprosthetic bone loss after hip arthroplasty.

Unlabelled: Our primary question was whether bone strength at the time of surgery, reflected by the lumbar spine T-score and femoral cortical thickness, influences periprosthetic bone loss after a total hip arthroplasty. Using dual energy xray absorptiometry we preoperatively and postoperatively examined 38 consecutive patients having cementless total hip arthroplasties for their bone density. Bone strength was estimated using lumbar spine bone mineral density and the ipsilateral diaphyseal cortical thickness of the femur measured on radiographs.