Alex Hollenberg - Academia.edu (original) (raw)

Uploads

Papers by Alex Hollenberg

Objective We sought to evaluate the influence of trauma-induced spinal cord injury (SCI) on the o... more Objective We sought to evaluate the influence of trauma-induced spinal cord injury (SCI) on the operative management of cervical ossification of the posterior longitudinal ligament (OPLL) in a North American cohort. Methods A retrospective chart review was performed for all patients who underwent surgical management for OPLL in an academic medical center between November 2006 and July 2019. Patients were categorized into 1 of 2 groups and compared on the basis of their initial presentation: 1) SCI with OPLL or 2) cervical myelopathy (CM) with OPLL. Patient characteristics were collected. OPLL classification and K-line measurements were performed. Surgical approach, levels fused/decompressed, blood loss, postoperative length of stay, surgical complications, and neurologic outcome were recorded. Results Among the 28-patient cohort, 12 were in the SCI with OPLL group and 16 were in the CM with OPLL group. The most common type of OPLL in both groups was segmental (n = 21, 75%). The aver...

The Journal of Hand Surgery

$Research paper thumbnail of Electromagnetic stimulation increases mitochondrial function in osteogenic cells and promotes bone fracture repair$

Scientific Reports

Bone fracture is a growing public health burden and there is a clinical need for non-invasive the... more Bone fracture is a growing public health burden and there is a clinical need for non-invasive therapies to aid in the fracture healing process. Previous studies have demonstrated the utility of electromagnetic (EM) fields in promoting bone repair; however, its underlying mechanism of action is unclear. Interestingly, there is a growing body of literature describing positive effects of an EM field on mitochondria. In our own work, we have previously demonstrated that differentiation of osteoprogenitors into osteoblasts involves activation of mitochondrial oxidative phosphorylation (OxPhos). Therefore, it was reasonable to propose that EM field therapy exerts bone anabolic effects via stimulation of mitochondrial OxPhos. In this study, we show that application of a low intensity constant EM field source on osteogenic cells in vitro resulted in increased mitochondrial membrane potential and respiratory complex I activity and induced osteogenic differentiation. In the presence of mitoch...

The American Journal of Sports Medicine

Background: Medial patellofemoral ligament (MPFL) reconstruction is an established operative proc... more Background: Medial patellofemoral ligament (MPFL) reconstruction is an established operative procedure to restore medial restraining force in patients with patellar instability. In the setting of a shallow sulcus, it is unclear whether an isolated MPFL reconstruction is sufficient to restore patellofemoral stability. Hypothesis: Progressively increasing the sulcus angle would have an adverse effect on the ability of an MPFL reconstruction to restrain lateral patellar motion. Study Design: Controlled laboratory study. Methods: Seven fresh-frozen human cadaveric knees were harvested and prepared for experimentation. Each specimen was run through the following test conditions: native, lateral retinacular release, lateral retinacular repair, MPFL release, MPFL reconstruction, and MPFL reconstruction with trochlear flattening. Four 3-dimensional printed wedges (10°, 20°, 30°, and 40°) were created to insert beneath the native trochlea to raise the sulcus angle incrementally and simulate ...

PLOS ONE

Spinal fusion is a commonly performed orthopedic surgery. Autologous bone graft obtained from the... more Spinal fusion is a commonly performed orthopedic surgery. Autologous bone graft obtained from the iliac crest is frequently employed to perform spinal fusion. Osteogenic bone marrow stromal (a.k.a. mesenchymal stem) cells (BMSCs) are believed to be responsible for new bone formation and development of the bridging bone during spinal fusion, as these cells are located in both the graft and at the site of fusion. Our previous work revealed the importance of mitochondrial oxidative metabolism in osteogenic differentiation of BMSCs. Our objective here was to determine the impact of BMSC oxidative metabolism on osseointegration of the graft during spinal fusion. The first part of the study was focused on correlating oxidative metabolism in bone graft BMSCs to radiographic outcomes of spinal fusion in human patients. The second part of the study was focused on mechanistically proving the role of BMSC oxidative metabolism in osseointegration during spinal fusion using a genetic mouse model...

Journal of orthopaedic research : official publication of the Orthopaedic Research Society, Jan 25, 2018

Annual scientific meetings serve as a forum for dissemination of new research findings. Presentat... more Annual scientific meetings serve as a forum for dissemination of new research findings. Presentations should be of high scientific quality as they have the potential to impact future research projects and current clinical practice. The publication rate of podium presentations at an annual meeting can be used to assess the quality of the research presented. The purpose of this study was to determine the publication rate of podium presentations at the Orthopaedic Research Society (ORS) annual meeting. All podium presentations from the 2012-2014 annual ORS meetings were identified. Abstracts were categorized into an orthopaedic topic. A PubMed search was performed to determine if an abstract reached publication in a peer-reviewed journal. The publication rate was determined for each year. Of the 1063 podium presentations identified, 640 (60.2%) reached publication in a peer-reviewed journal. No significant differences were observed in the publication rate between the orthopaedic topics...