Spine Fractures of Patients with Ankylosing Spondylitis and Diffuse Idiopathic Skeletal Hyperostosis: Fracture Severity and Injury-Related Mortality at a Level I Trauma Center.

STUDY DESIGN: Retrospective review of prospectively collected cohort. PURPOSE: To identify differences in treatment and mortality of spine fractures in patients with ankylosing conditions of the spine. OVERVIEW OF LITERATURE: Ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH) are the two most common etiologies of ankylosing spinal disorder (ASD). However, studies on the treatment and outcomes of spine fractures in AS and DISH patients remain few. METHODS: Patients presenting with a spine fracture were diagnosed with AS or DISH at a single tertiary care center between 2010 and 2019. We excluded those who lacked cross-sectional imaging or fractures occurring at spinal segments affected by ankylosis, as well as polytraumatized patients. Patient demographics, injury mechanism, fracture level, neurologic status, treatment, and 1-year mortality were recorded. Computed tomography imaging was reviewed by two independent readers and graded according to the indicated AO Spine Injury Classification System. Differences in fracture severity, treatment method, and mortality were examined using Student t -tests, chi-square tests, and two-proportion Z-tests with significance set to p <0.05. RESULTS: We identified 167 patients with spine fracture diagnosed with AS or DISH. Patients with AS had more severe fractures and more commonly had surgery than patients with DISH (p <0.001). Despite these differences, 1-year mortality did not significantly differ between AS and DISH patients (p =0.14). CONCLUSIONS: Although patients with AS suffered more severe fractures compared to DISH and more frequently underwent surgery for these injuries, outcomes and 1-year mortality did not differ significantly between the two groups. For patients with ASDs and fractures, outcomes appear similar regardless of treatment modality. Consequently, there may be an opportunity for critical reappraisal of operative indications in ASD and a larger role for nonoperative management in these challenging patients.

Risk Factors for Failure of Nonoperative Treatment for Unilateral Cervical Facet Fractures.

STUDY DESIGN: Retrospective clinical study. PURPOSE: The purpose of this study was to determine what percentage of patients who underwent nonoperative management of unilateral non-displaced or minimally displaced facet fractures progressed radiographically and to determine what percentage of patients required surgical intervention and to identify risk factors for failure of conservative management. OVERVIEW OF LITERATURE: According to most commonly used classification systems, unilateral, non-and minimally displaced facet fractures are be amendable to nonoperative management. METHODS: A retrospective review of the Trauma Registry of a Level I trauma center was performed to identify all patients diagnosed with a non- or minimally displaced unilateral facet fracture which was managed nonoperatively. Several demographic variables and clinical outcomes were recorded. Using computed tomography scanning and plain radiographs, fracture pattern, listhesis, displacement, angle and percentage of the facet that included the fracture were determined. Radiographic progression was defined as the occurrence of listhesis of more than 10% of the anterior-posterior dimensions of the inferior vertebral body during radiographic follow-up. Failure of conservative management was defined as a patient requiring surgical intervention after initially being managed nonoperatively. RESULTS: Seventy-four patients were included. Fifteen patients (20%) progressed radiographically. However, only 2 developed radicular symptoms and none developed myelopathy or other catastrophic cord related symptoms. Seven patients (9%) underwent surgery. Indications for surgery included significant radiographic progression and/or radicular symptoms. Risk factors for failure of conservative management included presence of radiculopathy at the time of presentation, a higher body mass index, increased Injury Severity Score, greater initial fracture displacement and more than 2 mm of listhesis. CONCLUSIONS: Patients with non-displaced or minimally displaced facet fractures who do not have neurological symptoms at the time of presentation can safely be managed conservatively with careful observation and follow-up.

Surgical Management of Cervical Spondylotic Myelopathy.

Cervical spondylotic myelopathy (CSM) is a common cause of neurologic impairment in adults worldwide. Numerous studies have investigated the pathophysiology of CSM, which has provided surgeons with insight on the important factors that lead to the symptoms and deficits observed in patients who have CSM. However, further analysis of many unknown aspects of CSM is required to fully understand the disease and potential alternative treatment modalities. The diagnosis of CSM is based on a patient's history and physical examination and then confirmed with imaging studies. Progression, symptomatology, and imaging findings may vary by patient. Because of the variability of CSM, the disease course and a patient's response to treatment are difficult to predict. CSM can be managed either nonsurgically or it can be managed surgically via posterior or anterior cervical approaches, each of which has its own indications and possible complications.

Mortality in elderly patients following operative and nonoperative management of odontoid fractures.

STUDY DESIGN: Retrospective matched cohort study. OBJECTIVE: To compare mortality in elderly patients with odontoid fractures after operative and nonoperative treatment. In addition, to evaluate potential factors that may increase the risk of mortality in the geriatric population after odontoid fracture. SUMMARY OF BACKGROUND DATA: Odontoid fractures represent the most common cervical spine fracture in patients over 70. In this population controversy exists as to the optimal treatment of odontoid fractures, especially type II fractures. METHODS: A retrospective review of all odontoid fractures in patients 75 years of age or older at our institution from 1996 to 2010 was performed. Comorbidities were stratified using the Charlson comorbidity index. Mortality was determined at 3 months, 1, and 5 years. RESULTS: A total of 96 patients were identified of which 75 met inclusion criteria. The average age of patients included was 82.3 years. The average Charlson comorbidity score for those operated on (2.37) was not significantly different from the nonoperative group (2.46), (P=0.45). At 3 months the operative group had a significantly lower mortality rate than the nonoperative group (P=0.024). There was no significant difference in 1-year (P=0.42) or 5-year (P=0.21) mortality between the operative and nonoperative cohorts. Of the patients treated nonoperatively, those who died within 3 months of treatment had a significantly higher Charlson score (3.98) than those who survived (2.14). Patients who survived at least 1 year after surgery had a significantly lower Charlson score (1.53) than those who died (3.22) within that time frame after surgery (P=0.05). CONCLUSIONS: There was no significant difference between 1- and 5-year mortality in patients treated operatively or nonoperatively. Regardless of treatment Charlson score had a significant impact on mortality. Age significantly affected mortality in patients treated surgically.

Nucleus pulposus replacement: basic science and indications for clinical use.

STUDY DESIGN: A critical review of available and emerging nucleus pulposus replacement implants. OBJECTIVES: To review the biomechanics, design, and clinical data of currently available and developing nucleus pulposus replacement technologies. SUMMARY OF BACKGROUND DATA: The interest in minimally invasive treatment of degenerative disc disease has grown as the technology for intervertebral motion-sparing devices continues to improve. Replacement of nucleus pulposus without anular obliteration represents a tempting alternative to spinal fusion procedures. The aim in nucleus pulposus replacement is to slow adjacent level degeneration, restore normal loads to the diseased level, and restore segmental spinal biomechanics. METHODS: A literature review of currently available biomaterials, biomechanics, and available preclinical and clinical data on nucleus pulposus replacement implants. RESULTS: New synthetic biomaterials have recently been developed to closely mimic native biomechanics during compressive loading cycles of the intervertebral disc. This, in conjunction with improved understanding of global spine biomechanics, has allowed the development of novel nucleus replacement implants. These implants are currently at different stages of preclinical and clinical investigations. CONCLUSIONS: Although some of the newly designed prosthesis have shown some promising results in preclinical studies, rigorous short- and long-term clinical evaluations will be critical in evaluating their true efficacy.

Enhancement of bone healing based on ex vivo gene therapy using human muscle-derived cells expressing bone morphogenetic protein 2.

Molecular biological advances have allowed the use of gene therapy in a clinical setting. In addition, numerous reports have indicated the existence of inducible osteoprogenitor cells in skeletal muscle. Because of this, we hypothesized that skeletal muscle cells might be ideal vehicles for delivery of bone-inductive factors. Using ex vivo gene transfer methods, we genetically engineered freshly isolated human skeletal muscle cells with adenovirus and retrovirus to express human bone morphogenetic protein 2 (BMP-2). These cells were then implanted into nonhealing bone defects (skull defects) in severe combined immune deficiency (SCID) mice. The closure of the defect was monitored grossly and histologically. Mice that received BMP-2-producing human muscle-derived cells experienced a full closure of the defect by 4 to 8 weeks posttransplantation. Remodeling of the newly formed bone was evident histologically during the 4- to 8-week period. When analyzed by fluorescence in situ hybridization, a small fraction of the transplanted human muscle-derived cells was found within the newly formed bone, where osteocytes normally reside. These results indicate that genetically engineered human muscle-derived cells enhance bone healing primarily by delivering BMP-2, while a small fraction of the cells seems to differentiate into osteogenic cells.