Assessing bone quality in hounsfield units using computed tomography: what value should be used to classify bone as normal or osteoporotic?

Purpose: The purpose of this study was to investigate threshold values for classifying bone as normal or osteoporotic based on Computed Tomography (CT) Hounsfield Units (HU) and to determine if clinically applicable values could be derived to aid spine surgeons evaluating bone quality using CT.

Methods: This literature review was completed using PubMed and Ovid (MedLine), using syntax specific to bone quality and CT. The included articles were original clinical studies assessing bone quality and utilized composite L1-L4 HU values compared against dual-energy X-ray absorptiometry (DEXA) values.

Five-year Follow-up of a Prospective Food and Drug Administration Investigational Device Exemption Trial Evaluating a PEEK-on-Ceramic Cervical Disk Replacement.

Study Design: Prospective trial comparing the investigation group to propensity-matched historic control group.

Objective: To evaluate five-year results of single-level PEEK-on-ceramic cervical total disc replacement (TDR) compared with a propensity-matched anterior cervical discectomy and fusion (ACDF) control group.

Summary Of Background Data: Cervical TDR has gained acceptance as a treatment for symptomatic disk degeneration.

Treatment of failed cervical total disc replacements in a series of 53 cases and description of a management strategy.

Purpose: To describe modes of failure of cervical TDR, their related treatment strategies, and to describe a management strategy for the treatment of failed cervical TDR.

Methods: This retrospective study was based on a consecutive series of 53 cervical TDR patients who underwent removal or revision surgery. Chart review was conducted to collect general descriptive data, reasons for TDR removal/revision, duration from index implantation to re-operation, and the subsequent procedure performed.

Clinical Outcome of Lumbar Hybrid Surgery in a Consecutive Series of Patients With Long-term Follow-up.

Study Design: This was a retrospective study combined with attempted prospective patient contact to collect current data.

Objective: The purpose of this study was to investigate the long-term clinical outcomes of patients undergoing lumbar hybrid surgery (total disk replacement (TDR) at one level and fusion at an adjacent level.

Summary Of Background Data: Many patients with symptomatic lumbar disk degeneration are affected at more than one level.

Removals and Revisions of Cervical Total Disc Replacement Devices in a Consecutive Series of 1626 Patients Beginning With the First Case Experience in 2003.

Study Design: Retrospective cohort study.

Objective: The purpose of this study was to investigate the rate of cervical total disc replacement (TDR) device removal or revision.

Background: Cervical TDR has gained acceptance as an alternative to anterior cervical discectomy and fusion in appropriately selected patients.

Impact of Age on the Occurrence of Vascular Complications in Patients Undergoing Anterior Lumbar Approach Surgery.

Study Design: Retrospective cohort study.

Objective: To investigate the impact of age on the incidence of vascular complications in patients undergoing anterior lumbar approach surgery.

Background: Anterior approach lumbar spinal surgery may facilitate the use of intervertebral devices with larger endplate coverage and increased lordosis.

Is the Use of Intraoperative Neuromonitoring Justified During Lumbar Anterior Approach Surgery?

Background: Intraoperative neuromonitoring (IONM) became widely used in spine surgery to reduce the risk of iatrogenic nerve injury. However, the proliferation of IONM has fallen into question based on effectiveness and costs, with a lack of evidence supporting its benefit for specific spine surgery procedures. The purpose of this study was to evaluate the use of IONM and the rate of neurological injury associated with anterior lumbar spinal surgery.

Lumbar Total Disk Replacement Device Removals and Revisions Performed During a 20-Year Experience with 2141 Patients.

Study Design: This was a retrospective study with prospective patient contact attempted to collect current data.

Objective: The purpose was to investigate the incidence and reasons for lumbar total disk replacement (TDR) removal or revision.

Summary Of Background Data: A concern regarding lumbar TDR was safety, particularly the need for device removal or revision.

Assessing lumbar vertebral bone quality: a methodological evaluation of CT and MRI as alternatives to traditional DEXA.

Purpose: The purpose of this study was to investigate the impact of various methods on the assessment of vertebral bone quality.

Methods: A consecutive series of 427 candidates for lumbar disc replacement with lumbar DEXA and MRI and/or CT scans were included. Two measurement techniques were used on CTs-a sagittal and axial.

Impact of previous lumbar spine surgery on the outcome of lumbar total disc replacement: analysis of prospective 5-year follow-up study data.

Purpose: It is sometimes anticipated that patients with prior spine surgery will have a compromised outcome from future procedures. The purpose of this study was to compare TDR outcomes in patients with prior lumbar spine surgery to those with no previous surgery.

Methods: Post hoc analysis was performed on 5-year follow-up data collected prospectively in the multi-centre FDA-regulated trial for the activL® Artificial Disc which involved 376 patients treated for single-level symptomatic disc degeneration.

Evaluation of Anterior Lumbar Interbody Fusion Performed Using a Stand-Alone, Integrated Fusion Cage.

Background: Anterior lumbar interbody fusion (ALIF) has been performed for many years. Often, posterior supplemental fixation has been used to provide additional stability to the operated segment. Interbody implants have evolved to incorporate unique designs, polyetheretherketone, integrated screws, and surface texture.

In which cases do surgeons specializing in total disc replacement perform fusion in patients with symptomatic lumbar disc degeneration?

Purpose: The purpose of this study was to investigate reasons and their frequency for why spine surgeons subspecializing in total disc replacement (TDR) performed lumbar fusion rather than TDR.

Methods: The study was based on a consecutive series of 515 patients undergoing lumbar TDR or fusion during a 5-year period by three surgeons specializing in TDR. For each fusion patient, the reason for not performing TDR was recorded.

Cervical Total Disk Replacement: Available Implant Size Matters.

Study Design: This study was a post hoc analysis of data collected from 2 Food and Drug Administration (FDA) Investigational Device Exemption (IDE) trials.

Objective: The purposes of this study were to: (1) measure disk space heights adjacent to the level to be treated with a total disk replacement (TDR); (2) analyze cervical disk space heights to be replaced with TDR; and (3) investigate the frequency of use of a smaller height TDR when available.

Summary Of Background Data: Cervical TDR produces outcomes noninferior or superior to anterior cervical discectomy and fusion.

Indirect Decompression for the Treatment of Degenerative Lumbar Stenosis.

Background: Surgical treatment of symptomatic lumbar stenosis has traditionally included laminectomy for direct decompression. With increasing options for lumbar interbody fusion, there has been growing interest in indirect decompression to treat degenerative stenosis. The primary purpose of this study was to determine whether indirect decompression via anterior lumbar interbody fusion (ALIF) can provide symptomatic relief in patients with lumbar spinal stenosis.

Effect of age on outcomes after allogeneic disc tissue supplementation in patients with chronic discogenic low back pain in the VAST trial.

 To explore the effects of viable allogeneic disc tissue supplementation in younger patients with discogenic chronic low back pain (CLBP). VAST was a randomized placebo-controlled trial of disc allograft supplementation in 218 patients with discogenic CLBP. We conducted a analysis of change from baseline to 12 months in Oswestry Disability Index (ODI) and visual analog scale for pain intensity scores stratified by patient age.

Incidence and Resolution Strategies for Early-Onset Postoperative Leg Pain Following Lumbar Total Disc Replacement.

Background: Lumbar total disc replacement (TDR) has produced results similar or superior to fusion in treating symptomatic disc degeneration. Some patients have reported onset of leg pain early after surgery. Little information is available specifically on this problem.

Cervical Total Disc Replacement: Novel Devices.

This article reviews the available literature for novel cervical total disc replacement devices, including ones which are available inside and outside of the United States. It includes biomechanical consideration as well as design characteristics and clinical data when available.

Single-Level Cervical Disc Replacement Using a PEEK-on-Ceramic Implant: Results of a Multicenter FDA IDE Trial With 24-Month Follow-up.

Background: Many early cervical total disc replacements (TDRs) produced motion through a ball-and-socket action, with metal endplates articulating with a plastic core. Polyetheretherketone (PEEK) is used increasingly for spinal implants due to its mechanical properties and lack of artifacts on imaging. A TDR was designed with titanium-coated PEEK endplates and a ceramic core.

Economics of Cervical Disc Replacement.

Background: Although extensive reports of clinical outcome after cervical disc replacement (CDR) and anterior cervical discectomy and fusion exist, few reviews of the cost-effectiveness research in cervical spine surgery exist. The purpose of this study was to review the concepts of cost-effectiveness research, the various approaches to cost-effectiveness studies in the context of cervical spine surgery, and some of the literature results.

Methods: Review article describing cost-effectiveness research concepts, methodology, and results.

Analysis of re-operations after cervical total disc replacement in a consecutive series of 535 patients receiving the ProDisc-C device.

Introduction: One important factor in evaluating the safety of an implant is the rate of subsequent surgery and the reasons for surgery, particularly those that are related to possible problems with the implant. The purpose of this study was to determine the overall re-operation rate (including revisions, removals, device-related, procedure-related, adjacent segment, and others) for a large consecutive series of cervical TDR patients beginning with the first case experience, using a single device at a single institution.

Methods: Surgery records were reviewed to identify cervical TDR patients and those who underwent subsequent surgery.

In which cases do surgeons specializing in total disc replacement perform fusion in patients with cervical spine symptoms?

Purpose: The purpose was to investigate reasons and their frequency for why total disc replacement (TDR) specialty surgeons performed anterior cervical discectomy and fusion (ACDF) rather than TDR.

Methods: A consecutive series of 464 patients undergoing cervical spine surgery during a 5-year period by three TDR specialty surgeons was reviewed. For each ACDF, the reason for not performing TDR was recorded.

Finite Element Based-Analysis for Pre and Post Lumbar Fusion of Adult Degenerative Scoliosis Patients.

Study Design: Pre-post cohort finite elements (FE).

Objectives: To investigate the effect of adjacent load transfer pre and post fusion surgery of lumbar scoliotic spines using FE models.

Summary Of Background Data: Adult degenerative scoliosis (ADS) results from age-related changes, leading to segmental instability, deformity, and stenosis.

A Comparison of Muscular Activity During Gait Between Walking Sticks and a Walker in Patients With Adult Degenerative Scoliosis.

Study Design: A repeated measurement, single-center, prospective study.

Objective: The purpose of this study is to compare and contrast the benefits of walking sticks versus a walker on the trunk and lower extremity muscular control in patients with adult degenerative scoliosis (ADS).

Summary Of Background Data: ADS patients demonstrate an altered gait pattern.

Effect of Cervical Decompression Surgery on Gait in Adult Cervical Spondylotic Myelopathy Patients.

Study Design: This is a prospective cohort study.

Objective: To evaluate the effect of cervical decompression surgery on the biomechanics of the spine and lower extremities in cervical spondylotic myelopathy (CSM) patients and compare with asymptomatic controls.

Summary Of Background Data: Difficulties with balance and gait are one of the most common manifestations of CSM.