Biomechanical Evaluation of a Dynamic Stabilization System for the Prevention of Proximal Junctional Failure in Adult Deformity Surgery.

Study Design: Biomechanical spine model. Comparison of stress in the implant and the adjacent cranial segment was done with conventional rigid versus dynamic stabilization system (DS) fixation.

Objective: The aim of this study was to study stress at the proximal end of spinal fixation with a novel DS.

Clinical Incidence of PJK/ASD in Adult Deformity Surgery: A Comparison of Rigid Fixation and Semirigid Fixation-Semirigid.

In the debate regarding whether rigid or semirigid fixation is better for proximal junctional kyphosis (PJK)/adult spinal deformity (ASD) correction, this presentation posits that semirigid fixation is the better approach. For ASD correction, might is not right, and a rigid approach does not solve the problems associated with PJK.

The basis of mechanical instability in degenerative disc disease: a cadaveric study of abnormal motion versus load distribution.

Study Design: A biomechanical study in cadaveric lumbar spine.

Objective: To establish the basis of mechanical stability in degenerative disc disease from the relationship between range of motion (ROM), neutral zone motion (NZ), intradiscal pressure profile, and instantaneous axis or rotation (IAR) in advancing grades of disc degeneration.

Summary Of Background Data: The basis of mechanical instability in lumbar disc degeneration remains poorly understood.

How fast pain, numbness, and paresthesia resolves after lumbar nerve root decompression: a retrospective study of patient's self-reported computerized pain drawing.

Study Design: A single-center retrospective study.

Objective: To compare the speed of recovery of different sensory symptoms, pain, numbness, and paresthesia, after lumbar nerve root decompression.

Summary Of Background Data: Lumbar radiculopathy is characterized by different sensory symptoms like pain, numbness, and paresthesia, which may resolve at different rates after surgical decompression.

Pedicle screw-based posterior dynamic stabilization: literature review.

Posterior dynamic stabilization (PDS) indicates motion preservation devices that are aimed for surgical treatment of activity related mechanical low back pain. A large number of such devices have been introduced during the last 2 decades, without biomechanical design rationale, or clinical evidence of efficacy to address back pain. Implant failure is the commonest complication, which has resulted in withdrawal of some of the PDS devices from the market.

New treatments and imaging strategies in degenerative disease of the intervertebral disks.

Magnetic resonance (MR) imaging in patients with persistent low back pain and sciatica effectively demonstrates spine anatomy and the relationship of nerve roots and intervertebral disks. Except in cases with nerve root compression, disk extrusion, or central stenosis, conventional anatomic MR images do not help distinguish effectively between painful and nonpainful degenerating disks. Hypoxia, inflammation, innervation, accelerated catabolism, and reduced water and glycosaminoglycan content characterize degenerated disks, the extent of which may distinguish nonpainful from painful ones.

Instant axis of rotation of L4-5 motion segment--a biomechanical study on cadaver lumbar spine.

The instant axis of rotation (IAR) is an important kinematic property to characterise of lumbar spine motion. The goal of this biomechanical study on cadaver lumbar spine was to determine the excursion of the IAR for flexion (FE), lateral bending (LB) and axial rotation (AR) motion at L4-5 segment. Ten cadaver lumbar spine specimens were tested in a 6 degrees-of-freedom spine tester with continuous clyclical loading using pure moment and follower pre-load, to produce physiological motion.

Intraoperative ketamine reduces perioperative opiate consumption in opiate-dependent patients with chronic back pain undergoing back surgery.

Background: Ketamine is an N-methyl-d-aspartate receptor antagonist that has been shown to be useful in the reduction of acute postoperative pain and analgesic consumption in a variety of surgical interventions with variable routes of administration. Little is known regarding its efficacy in opiate-dependent patients with a history of chronic pain. We hypothesized that ketamine would reduce postoperative opiate consumption in this patient population.

Biomechanical evaluation of the kinematics of the cadaver lumbar spine following disc replacement with the ProDisc-L prosthesis.

Study Design: Biomechanical study of the ProDisc-L in a cadaveric model under pure moment loading. OBJECTIVE.: To determine the kinematic properties of a lumbar spine motion segment and the adjacent level following ProDisc-L disc replacement in the cadaveric spine.

Development of a 4-axis load cell used for lumbar interbody load measurements.

Numerous studies have assessed lumbar interbody fusion, but little data from direct interbody load measurements exists. This manuscript describes an interbody fusion cage with integrated 4-axis load cell that can simulate implant heights of 13, 15, 17, 19 and 21 mm. The calibrated load cell was accurate to within 7.

Cervical spine trauma.

Cervical spine trauma is a common problem with a wide range of severity from minor ligamentous injury to frank osteo-ligamentous instability with spinal cord injury. The emergent evaluation of patients at risk relies on standardized clinical and radiographic protocols to identify injuries; elucidate associated pathology; classify injuries; and predict instability, treatment and outcomes. The unique anatomy of each region of the cervical spine demands a review of each segment individually.

Outcome of local bone versus autogenous iliac crest bone graft in the instrumented posterolateral fusion of the lumbar spine.

Study Design: Retrospective, comparative study of clinical and radiologic outcome with independent, blinded observer.

Objectives: To compare the clinical and radiologic outcome of instrumented posterolateral lumbar fusion using local bone versus autogenous iliac crest bone graft (ICBG).

Summary Of Background Data: There is no published report of outcome of posterolateral spinal fusion using local bone alone for degenerative disorders of the lumbar spine.

Fulcrum assisted soft stabilization system: a new concept in the surgical treatment of degenerative low back pain.

Study Design: An experimental study on cadaver spine and spine model for biomechanical evaluation of a novel dynamic stabilization device.

Objectives: First, to test the hypothesis that in dynamic stabilization of a lumbar spine using pedicle screws and ligament, addition of a fulcrum in front of the ligament can unload the disc. Second, to determine the relationship between the length and stiffness of the fulcrum and the ligament on disc unloading, lordosis and motion preservation.

Degenerative spondylolisthesis: review of current trends and controversies.

Study Design: A literature-based review.

Objectives: To review management and controversies and to present authors recommendations.

Summary Of Background Data: There is considerable controversy regarding indication for surgery, role for decompression alone, and decompression with fusion with or without instrumentation.

Neglected spinal injuries.

Neglected spinal injuries secondary to overlooked diagnosis may result in serious medical and medicolegal problems. These are not uncommon but are reported infrequently in the medical literature. I studied the incidence, causes, and consequences of neglected spinal injuries and recommendations for prevention and treatment by reviewing the literature found in a Medline search.

Dynamic stabilization devices in the treatment of low back pain.

Soft stabilization has an important role in the treatment of the degenerative lumbar spine. Fusion of one or two motion segments may not make a big difference in the total range of motion of the lumbar spine, but preserving flexibility of a motion segment may prevent adjacent segment disease and may permit disc replacement, even when facet joints need to be excised. If a favorable environment is created in the motion segment by unloading the disc and permitting near normal motion, the disc may be able to repair itself or may supplement the reparative potential of gene therapy.

Lumbar spinal stenosis. Treatment strategies and indications for surgery.

Initially, all patients with degenerative lumbar spinal stenosis should be treated conservatively. Rapid deterioration is unlikely. The majority of patients may either improve or remain stable over a long-term follow-up with nonoperative treatment.

Pelvic or lumbar fixation for the surgical management of scoliosis in duchenne muscular dystrophy.

Study Design: This retrospective study evaluates two groups of patients with scoliosis and Duchenne muscular dystrophy, treated with two different surgical stabilization methods.

Objective: To determine whether fixation to the sacropelvis is always necessary for adequate stabilization of scoliosis in Duchenne muscular dystrophy.

Summary Of Background Data: Pelvic fixation is generally recommended for scoliosis in Duchenne muscular dystrophy.

Rationale, principles and experimental evaluation of the concept of soft stabilization.

The apparent clinical success of spinal stabilization methods that restrict rather than abolish movement in relieving mechanical back pain indicates that the concept of the aetiology of back pain should be reviewed. Further understanding of how degeneration affects disc biomechanics, and an understanding of how current soft stabilization systems alters them, may allow us to define more precisely what are the essential requirements of an ideal soft stabilization system. It appears that abnormal patterns of loading rather than abnormal movement are the reason that disc degeneration causes back pain in some patients.