Treatment of facet cysts associated with neurogenic intermittent claudication with x-stop

Development of Bilateral Facet Cysts Causing Recurrent Symptoms After Decompression and the Placement of an Intralaminar Implant: A Case Report

CASE

We report the development of bilateral symptomatic facet joint cysts in a 78-year-old man who had been treated with decompression and placement of a coflex device (Paradigm Spine) at L3-L4 and L4-L5. Preoperative imaging clearly demonstrated fluid in the facet joints without cysts. He underwent standard surgical treatment, but developed symptomatic facet joint cysts at 4 months postoperatively. The patient was treated with a revision decompression and replacement of the devices; there were no issues at the 32-month follow-up.

CONCLUSION

While the coflex device has possible long-term biomechanical advantages, vigilance with adherence to appropriate decompression surgical technique is necessary.

Operation of Lumbar Zygoapophyseal Joint Cysts Using a Full-Endoscopic Interlaminar and Transforaminal Approach

In appropriate situations, extensive decompression with laminectomy often continues to be described as the method of choice for operations involving lumbar zygoapophyseal joint (z-joint) cysts. Tissue-sparing procedures are nevertheless becoming more common. Endoscopic techniques have become the standard procedures in many areas because of the advantages they offer in terms of surgical technique and in rehabilitation. One key aspect in spinal surgery was the development of instruments for sufficient bone resection carried out under continuous visual control. This enabled endoscopes to be used when operating on z-joint cysts. The objective of this prospective study was to examine the technical possibilities for the full-endoscopic interlaminar and transforaminal technique in lumbar z-joint cysts. A total of 74 patients were followed up for 2 years. The results show that 85% of the patients no longer have any leg pain or that the pain had been almost completely eliminated, and 11 % experience occasional pain. The complication rate was low. The full-endoscopic techniques brought advantages in the following areas: operation, complications, traumatization, and rehabilitation. The recorded results show that full-endoscopic resection of a z-joint cyst using an interlaminar and transforaminal approach provides an adequate and safe supplement, and is an alternative to conventional procedures when the indication criteria are fulfilled. It also offers the advantages of a minimally invasive intervention.

Finite element analysis of the biomechanical effect of coflex™ on the lumbar spine

Objective

The biomechanical properties of the Coflex™ (Paradigm Spine, NY, USA), a device designed to provide dynamic stabilization without lumbar fusion, have not been clearly defined. The purpose of this study was to determine the efficacy and biomechanical effect of Coflex™ using finite element model (FEM).

Methods

A 3D geometric model of the L3-L5 was created by integrating computerized tomography (CT) images. Based on the geometric model, a 3D FEM was created and the Coflex™ model was incorporated into the base model. Mechanical load dependent on the postural changes and boundary conditions, were imposed to simulate various 3D physiological states. The simulation analysis included stress and strain distributions, intervertebral disc deformation, and the range of motion of the facet joint and lumbar spinous process.

Results

Coflex™ significantly restrained displacement in extension, lateral bending and compression of joint between the L4-5 as one in the experimental group was observed -1.3% of flexion, -24.5% of extension, -44.5% of lateral bending and -37.2%. The average intradiscal pressure of the L4-5 decreased by 63% and the average facet contract force of the L4-5 decreased markedly by 34% in the experimental group. A load of 120 MPa from extension was observed at the base of spinous process in the experimental group.

Conclusion

The Coflex™ can be safely used for achieving functional dynamic stabilization of the lumbar vertebral column while preserving the intactness of the other components. However, the fatigue fracture of the L4 spinous process should be carefully monitored.