Determination of the in vivo posterior loading environment of the Coflex interlaminar-interspinous implant.

Background Context: The in vivo loading environment of load-bearing implants is generally largely unknown. Loads are typically approximated from cadaver tests or biomechanical calculations for the preclinical assessment of a device's safety and efficacy.

Purpose: To determine the actual in vivo loading environment of an elastic interlaminar-interspinous implant (Coflex).

A biomechanical evaluation of an interspinous device (Coflex) used to stabilize the lumbar spine.

A biomechanical study of an interspinous stabilization spinal implant (Coflex) was carried out using eight human lumbar L4/L5 motion segments. Each motion segment was tested in compression, then flexion/extension, then lateral bending, and then axial rotation at five conditions: 1) intact; 2) partial destabilization (by cutting the supraspinous and interspinous ligaments, the ligamentum flavum, the facet capsules, and 50% of the inferior bony facet bilaterally); 3) stabilization with the Coflex device; 4) complete destabilization with total laminectomy; and 5) stabilization with pedicle screws and rods. The most important result is that the motion segment after destabilization and insertion of the Coflex device does not allow significantly more or less motion than the intact specimen in either flexion/extension or axial rotation.

AcroFlex design and results.

The AcroFlex prosthesis is unique when compared to other current devices, as it has an elastomeric core sandwiched between two titanium endplates. The purpose of this design was to optimize shock absorption qualities. This paper reviews the design of the AcroFlex Disc and relevant design and outcomes of two pilot studies carried out on 28 patients using the AcroFlex prosthesis.

Arterial complications following anterior lumbar interbody fusion: report of eight cases.

The objective of this study is to report eight cases of arterial complication following anterior lumbar interbody fusion (ALIF) and to analyze the data in order to identify possible risk factors. The authors have encountered six cases of common iliac artery occlusion and two cases of acute vasospasm as a complication of ALIF using two different approaches to spine: hypogastric-midline-transperitoneal approach at one center and minimally invasive muscle-sparing retroperitoneal approach at the other. All cases involved surgery at the L4-L5 level.

Histology of tissues within retrieved human titanium mesh cages.

Study Design: Histologic documentation of contents within retrieved, failed human titanium mesh cages.

Objectives: The purpose of this study is to describe the contents of a series of retrieved, clinically failed titanium mesh cages from human patients.

Summary Of Background Data: The use of interbody fusion cages is gaining rapid acceptance, but there is little histologic documentation of tissue within retrieved cages.

Total disc replacement arthroplasty using the AcroFlex lumbar disc: a non-human primate model.

Using a non-human primate model, the current study was undertaken to investigate the efficacy of the AcroFlex lumbar disc as an intervertebral disc prosthesis, based on biomechanical, histopathologic and histomorphometric analyses. A total of 20 mature male baboons (Papio cynocephalus, mean weight 30 kg) were randomized into two equal groups based on post-operative time periods of 6 (n=10) and 12 months (n=10). Each animal underwent an anterior transperitoneal surgical approach to the lumbar spine, with intervertebral reconstructions performed at L3-L4 and L5-L6 using the following techniques: (1) tricortical iliac autograft and (2) AcroFlex lumbar disc.