Publications by authors named "Timothy Witham"

Objective: To (1) create a novel tissue-engineered bone graft comprising the osteoinductive oxysterol Oxy133 and (2) compare the osteogenic capability of this novel bone graft with bone graft substitutes previously examined.

Methods: Oxy133 was homogeneously incorporated into a biomimetic bone graft substitute (BioMim) comprising extracellular matrix and calcium phosphates. Two iterations of the graft were created: one corresponding to an implant-dose of 2.

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Purpose: This study sought to compare screw placement accuracy and outcomes between freehand (FH) and AR-guided pelvic fixation. While pelvic fixation is a critical technique in spinal deformity surgery, S2-alar iliac (S2AI) screw placement poses challenges.

Methods: We conducted a case-control study of 50 consecutive patients who underwent spinopelvic fixation at a single institution.

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Study Design: Narrative review.

Objective: The objective of this study is to explore and evaluate the role of novel technologies in enhancing the diagnosis, surgical precision, and rehabilitation of cervical spine trauma, and to discuss their potential impact on clinical outcomes.

Summary Of Background Data: Traumatic cervical spine injuries are challenging to manage due to their complex anatomy, the potential for long-term disability, and severe neurological deficits.

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Background: The accurate and safe positioning of cervical pedicle screws is crucial. While augmented reality (AR) use in spine surgery has previously demonstrated clinical utility in the thoracolumbar spine, its technical feasibility in the cervical spine remains less explored.

Purpose: The objective of this study was to assess the precision and safety of AR-assisted pedicle screw placement in the cervical spine.

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Background: Using a multi-institutional oncology database, we investigate the survival rates and the impacts of demographic, clinical, and management characteristics on overall survival among adult patients diagnosed with spinal ependymoma.

Methods: Utilizing the SEER registry, patients with histologically or radiologically confirmed ependymomas were included. Factors impacting overall survival were analyzed using Kaplan-Meier survival curves and log-rank statistical analyses.

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Background And Objectives: Spinal chordomas are primary bone tumors where surgery remains the primary treatment. However, their low incidence, lack of evidence, and late disease presentation make them challenging to manage. Here, we report the postoperative outcomes of a large cohort of patients after surgical resection, investigate predictors for overall survival (OS) and local recurrence-free survival (LRFS) times, and trend functional outcomes over multiple time periods.

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Background: Postoperative infection is a complication of spinal fusion surgery resulting in increased patient morbidity. Strategies including intraoperative application of powdered vancomycin have been proposed to reduce the incidence of infection; however, such antimicrobial effects are short-lived.

Methods: Instrumentation of the L4-L5 vertebrae was performed mimicking pedicle screw and rod fixation in 30 rats.

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Objective: There is limited consensus regarding management of spinal epidural abscesses (SEAs), particularly in patients without neurologic deficits. Several models have been created to predict failure of medical management in patients with SEA. We evaluate the external validity of 5 predictive models in an independent cohort of patients with SEA.

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Article Synopsis
  • The study explores the use of MR imaging in spine surgery to enhance treatment planning and reduce radiation exposure, especially in pediatric cases where CT scans are limited.
  • A novel method is introduced for aligning preoperative MR images with intraoperative long-length tomosynthesis images using a generative adversarial network and a sophisticated registration algorithm, demonstrating significant accuracy improvements.
  • Results showed low projection and registration errors in both cadaver tests and clinical images, validating the method's robustness and effectiveness in managing spinal anatomy during surgery.
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Augmented reality (AR) and virtual reality (VR) are powerful technologies with proven utility and tremendous potential. Spine surgery, in particular, may benefit from these developing technologies for resident training, preoperative education for patients, surgical planning and execution, and patient rehabilitation. In this review, the history, current applications, challenges, and future of AR/VR in spine surgery are examined.

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The extracorporeal telescope (exoscope) presents a novel digital camera system as a versatile alternative to traditional optical microscopy for microsurgery and minimally invasive neurosurgical operations. Recent innovations in exoscope technology offer 4K-definition multiscreen outputs, pneumatic robot arms, 3-dimensional depth perception, and greater illumination, focus, and magnification powers for enhanced intraoperative visualization. The authors present their initial institutional experience using a robotic arm-enabled 4K 3D exoscope in a variety of cranial and spinal neurosurgical operations, namely Chiari decompression, microvascular decompression for trigeminal neuralgia, anterior cervical discectomy, and lumbar decompressions.

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Article Synopsis
  • Growing evidence suggests that prompt surgical intervention is crucial for patients with traumatic spinal cord injury (tSCI), especially those who may also have traumatic brain injury (TBI), which complicates timely diagnosis and treatment.
  • A study analyzed data from nearly 15,000 tSCI patients across 377 trauma centers, revealing that those with TBI faced longer wait times for surgery, averaging 24.8 hours compared to 20.0 hours for those without TBI.
  • The research indicates that severe TBI significantly increases the likelihood of surgical delays in tSCI patients, highlighting the need for urgent management in such cases.
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Technological advancements, particularly in the realm of augmented reality (AR), may facilitate more accurate and precise pedicle screw placement. AR integrates virtual data into the operator's real-world view, allowing for the visualization of patient-specific anatomy and navigated trajectories. We aimed to conduct a meta-analysis of the accuracy of pedicle screw placement using AR-based systems.

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Background Context: The optimal decompression time for patients presenting with acute traumatic central cord syndrome (ATCCS) has been debated, and a high level of evidence is lacking.

Purpose: To compare early (<24 hours) versus late (≥24 hours) surgical decompression for ATCCS.

Study Design: Systematic review and meta-analysis.

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Introduction: Cervical spondyloptosis is a rare complication of high-energy trauma which often results in significant patient morbidity and mortality. The authors present a case of spondyloptosis of C7 over T1 with minimal radicular symptoms and otherwise complete spinal cord sparing. This case highlights the surgical challenges faced with cervical spondyloptosis and the techniques used when traction fails.

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Background Context: Augmented reality (AR) is increasingly recognized as a valuable tool in spine surgery. Here we provides an overview of the key developments and technological milestones that have laid the foundation for AR applications in this field. We also assess the quality of existing studies on AR systems in spine surgery and explore potential future applications.

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Background: Tarlov cysts are perineural collections of cerebrospinal fluid most often affecting sacral nerve roots, which may cause back pain, extremity paresthesias and weakness, bladder/bowel dysfunction, and/or sexual dysfunction. The most effective treatment of symptomatic Tarlov cysts, with options including non-surgical management, cyst aspiration and injection of fibrin glue, cyst fenestration, and nerve root imbrication, is debated.

Methods: Retrospective chart review was conducted for 220 patients with Tarlov cysts seen at our institution between 2006 and 2021.

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Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are well-recognized challenges of surgery for adult spinal deformity (ASD). Multiple risk factors have been identified for PJK/PJF, including osteoporosis, frailty, neurodegenerative disease, obesity, and smoking. Several surgical techniques to mitigate risk of PJK/PJF have been identified; however, patient optimization is also critical.

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Background And Objectives: Sacroiliac (SI) joint dysfunction constitutes a leading cause of pain and disability. Although surgical arthrodesis is traditionally performed under open approaches, the past decade has seen a rise in minimally invasive surgical (MIS) techniques and new federally approved devices for MIS approaches. In addition to neurosurgeons and orthopedic surgeons, proceduralists from nonsurgical specialties are performing MIS procedures for SI pathology.

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Background Context: Bacterial infection of spinal instrumentation is a significant challenge in spinal fusion surgery. Although the intraoperative local application of powdered vancomycin is common practice for mitigating infection, the antimicrobial effects of this route of administration are short-lived. Therefore, novel antibiotic-loaded bone grafts as well as a reliable animal model to permit the testing of such therapies are needed to improve the efficacy of infection reduction practices in spinal fusion surgery.

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Study Design: International survey.

Objectives: C5 palsy (C5P) is a neurological complication affecting 5-10% of patients after cervical decompression surgery. Most cases improve with conservative treatment; however, nearly 20% of patients may be left with residual deficits.

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Objective: Infuse bone graft is a widely used osteoinductive adjuvant; however, the simple collagen sponge scaffold used in the implant has minimal inherent osteoinductive properties and poorly controls the delivery of the adsorbed recombinant human bone morphogenetic protein-2 (rhBMP-2). In this study, the authors sought to create a novel bone graft substitute material that overcomes the limitations of Infuse and compare the ability of this material with that of Infuse to facilitate union following spine surgery in a clinically translatable rat model of spinal fusion.

Methods: The authors created a polydopamine (PDA)-infused, porous, homogeneously dispersed solid mixture of extracellular matrix and calcium phosphates (BioMim-PDA) and then compared the efficacy of this material directly with Infuse in the setting of different concentrations of rhBMP-2 using a rat model of spinal fusion.

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Objective: The optimal surgical approach for patients with multilevel degenerative cervical myelopathy (DCM) remains unknown. This systematic review and meta-analysis sought to compare anterior cervical discectomy and fusion (ACDF) versus posterior decompression (PD) in patients with DCM spanning ≥ 2 levels without ossification of the posterior longitudinal ligament.

Methods: MEDLINE and PubMed were searched from inception to February 22, 2022.

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