[Bilateral L3 spondylolysis. A case report and an overview of spondylolytic defect repair techniques]. / Spondylolýza L3. Kazuistika a prehled pouzívaných technik fúze spondylolytického defektu.

The direct fusion methods for repair of spondylolytic defects of the lumbar spine have recently been replaced by transpedicular screw fixation of the affected segment, in combination with PLIF, TLIF or ALIF procedures. However, in clearly indicated cases, such as a younger patient with no intervertebral disc degeneration and only minimal or no displacement of the vertebra, the direct repair techniques have a great advantage over transpedicular fixation because they preserve segmental motion The paper reports on a patient with spondylolysis at L3 who underwent surgery combining the Tokuhashi and Matsuzaki and the Gillet and Petit techniques, which involved a system of transpedicular screws, rods and sublaminar hooks supplemented with a cross-connector to support the base of the spinous process. After surgery, the patient reported pain relief and return to normal activities and CT examination showed bony union of both spondylolytic defects.

Surgical and clinical results with the PDN prosthetic disc-nucleus device.

The PDN prosthetic disc-nucleus device has been in use for 6 years, both in clinical trials and through commercial sale. Surgical and clinical data for the device have been collected and analyzed to help determine the strengths and limitations of the implant. The shape of the device has been found to be an important element in predicting surgical success, with wedge and rectangular devices being the most stable. The patient's disc dimensions are also critically important. Data indicate that patients with a disc height of less than 5 mm should be excluded from surgery. Moreover, the anterior-posterior (AP) diameter of the disc endplates must be 37 mm or more in order to properly situate two devices within the disc--patients with a smaller AP diameter should receive only a single device. Body mass and overall patient weight are also good predictors of surgical success. If the patient's body mass index is 30 or greater, then the patient should not receive the implants. Complications related to the PDN implant have included migration of the device and endplate remodeling in some patients. This endplate remodeling has usually been mild, and has occurred in response to the change in load distribution. In a few cases there has been more pronounced remodeling with a loss of disc height. To minimize endplate remodeling, the PDN hydrogel has been reformulated to be softer, absorbing 80% of its weight in water. Subsequent to implementing changes in device design and patient selection, and with the introduction of the ALPA (Anterior-Lateral transPsoatic Approach) technique for implanting the devices, there has been an increase in surgical success with a concomitant reduction in the number of revision surgeries. The current surgical success rate for patients implanted from 1999 through 2001 is 88%. Clinical results are also very encouraging, with marked decreases in Oswestry and visual analog scale pain levels, and disc height also shows improvement and stabilization.

[Fusion implants of carbon fiber reinforced plastic]. / Fusionsimplantate aus kohlenstofffaserverstärktem Kunststoff.

Carbon fiber reinforced plastics (CFRP) are used in the medical field when high mechanical strength, innovative design, and radiolucency (see spinal fusion implants) are needed. During the manufacturing process of the material CFRP carbon fibers are embedded into a resin matrix. This resin material could be thermoset (e.g., epoxy resin EPN/DDS) or thermoplastic (e.g., PEAK). CFRP is biocompatible, radiolucent, and has higher mechanical capabilities compared to other implant materials. This publication demonstrates the manufacturing process of fusion implants made of a thermoset matrix system using a fiber winding process. The material has been used clinically since 1994 for fusion implants of the cervical and lumbar spine. The results of the fusion systems CORNERSTONE-SR C (cervical) and UNION (lumbar) showed no implant-related complications. New implant systems made of this CFRP material are under investigation and are presented.

[Mechanical studies of lumbar interbody fusion implants]. / Mechanische Untersuchungen von lumbalen interkorporellen Fusionsimplantaten.

In addition to autogenous or allogeneic bone grafts, fusion cages composed of metal or plastic are being used increasingly as spacers for interbody fusion of spinal segments. The goal of this study was the mechanical testing of carbon fiber reinforced plastic (CFRP) fusion cages used for anterior lumbar interbody fusion. With a special testing device according to American Society for Testing and Materials (ASTM) standards, the mechanical properties of the implants were determined under four different loading conditions. The implants (UNION cages, Medtronic Sofamor Danek) provide sufficient axial compression, shear, and torsional strength of the implant body. Ultimate axial compression load of the fins is less than the physiological compression loads at the lumbar spine. Therefore by means of an appropriate surgical technique parallel grooves have to be reamed into the endplates of the vertebral bodies according to the fin geometry. Thereby axial compression forces affect the implants body and the fins are protected from damaging loading. Using a supplementary anterior or posterior instrumentation, in vivo failure of the fins as a result of physiological shear and torsional spinal loads is unlikely. Due to specific complications related to autogenous or allogeneic bone grafts, fusion cages made of metal or carbon fiber reinforced plastic are an important alternative implant in interbody fusion.

[Mechanical study of spinal interbody implants--characteristics and limits of standardized testing]. / Mechanische Untersuchung von interkorporellen Wirbelsäulen-Implantaten--Besonderheiten und Grenzen einer normgerechten Testung.

Spinal interbody fusion has proved to be a useful procedure for the surgical stabilization of spinal segments, for which fusion cases made of metal or reinforced polymers are increasingly being used. For the mechanical testing of spinal interbody implants, a test setup has been developed on the basis of an ASTM proposal. Initially, testing of lumbar fusion cages made of CFRP (carbon fibre reinforced polymer) was carried out. The implants (UNION Cages, Medtronic Sofamor Danek), which are characterised by their radiolucency on radiography, NMR and CT scans, have a cube-shaped body with three table-tracks on the under and upper surfaces. The cages were tested at different loads. Modifications of the proposed standardized method were carried out to enable implementation of implant-oriented testing. The tested cages were shown to have adequate axial compression, shear and torsional strengths with regard to the implant body. The maximum axial compression force tolerated by the table-tracks was less than the maximal potential loading of the lumbar spine, and, with account being taken of implant design, consequences with regard to surgical technique were drawn. As dictated by the geometry of the table-tracks, parallel grooves have to be made intra-operatively in the vertebral end plates. Axial compressive loads then act on the implant body, and the table-tracks are protected from damage. To avoid in vivo failure, the tested cages should be implanted only when this specific surgical technique is employed. Using supplementary anterior or posterior instrumentation, in vivo failure of the table-tracks under physiological spinal loading is not to be expected.

Bilateral primary mucinous carcinoma of the eyelid treated with Mohs surgery.

BACKGROUND: Primary mucinous carcinoma is an uncommon malignant cutaneous tumor which arises most commonly on the eyelid. While rarely causing death, recurrence following primary excision is common and widespread metastasis may occur. OBJECTIVE: We report the first case of bilateral primary mucinous carcinoma of the eyelid. METHODS: A lesion of the left lower eyelid had been resected three times previously with positive conventional margins. Both this lesion and a second primary lesion of the contralateral lower lid were removed with Mohs microscopically controlled excision without recurrence for more than 2 years. CONCLUSION: Multiple lesions of mucinous carcinoma of the eyelid do not necessarily connote metastasis. Mohs microscopically controlled excision may be a suitable form of therapy for primary mucinous carcinoma of the eyelid.

Immunohistochemical localization of the small proteoglycans decorin and biglycan in human intervertebral discs.

Immunohistochemistry was used to study the presence and distribution of the core proteins of the small proteoglycans decorin and biglycan in the various compartments of human intervertebral discs. Both proteoglycans could be found in the outer tendon-like parts of the annulus fibrosus, indicating their potential role in collagen network formation and biomechanical stress resistance. The loss of both proteoglycans in the annulus of individuals older than 50 years reflects a normal age-related change. In the nucleus pulposus, decorin could be found in fibrillar areas of the interterritorial matrix, thereby indicating co-localization of decorin with fibrils containing type II collagen. Biglycan was present in the extracellular matrix of the nucleus pulposus of adults. The pericellular immunoreactive rims observed around nucleus pulposus cells and giant chondrones indicated local biosynthetic activity for these small proteoglycans. The staining patterns in cartilage endplates resembled those found in human hyaline articular cartilage.

Photopenia in chronic vertebral osteomyelitis with technetium-99m-antigranulocyte antibody (BW 250/183).

UNLABELLED: Photon-deficient areas in 99mTc/111 in white blood cell (WBC) images for diagnosing vertebral osteomyelitis have been published often. This study retrospectively evaluated whether the use of 99mTc-labeled monoclonal antigranulocyte antibodies (BW 250/183) is superior to WBC and whether it offers higher specificity. METHODS: The study included 81 patients (46 men, 35 women; mean age 55 +/- 2 yr; from 1989 to 1995) with clinically suspected vertebral osteomyelitis who underwent scintigraphic imaging after intravenous injection of 555 MBq 99mTc-labeled monoclonal antigranulocyte antibodies. Forty patients suffered from osteomyelitis (20 men, 20 women; mean age 56 +/- 6 yr), 6 patients had metastases, 28 patients had spondylosis and disk herniation and 5 patients vertebral compression fractures. Diagnosis was not histologically verified in 2 patients. Planar imaging was performed at 4 and 24 hr postinjection. Histology of osteomyelitis was available in 30 patients, clinical follow-up in 10 patients. Visual uptake scores and quantitative uptake scores of the suspected areas were calculated. The results were compared to a semiquantitative histological score (high, medium, low grade) as well as to the scintigraphic scores. RESULTS: Scintigraphy showed photopenia in all patients with histologically proven vertebral osteomyelitis, independent of the grade of infection. A quantitative evaluation of 4 and 24 hr postinjection demonstrated a 58% increase of the uptake score in cases of histologically proven high-grade infections. This increase was seen predominantly in the thoracic spine but not in lumbar spine. All nonosseous paravertebral abscesses (n = 2) showed positive images and an increasing uptake over 24 hr. CONCLUSION: Paravertebral soft tissue infections can be differentiated excellently, whereas vertebral osteomyelitis, vertebral tumors or fractures can be localized, but no differentiation is possible.

The BWM spinal fixator system. A preliminary report of a 2-year prospective, international multicenter study in a range of indications requiring surgical intervention for bone grafting and pedicle screw fixation.

STUDY DESIGN: A prospective, international, multicenter study of 400 patients who received the BWM fixator system. OBJECTIVES: To assess the effectiveness and safety of the system in the management of various conditions requiring spinal fixation and bone grafting. SUMMARY OF BACKGROUND DATA: The BWM system was developed for the management of spinal instability of all etiologies occurring in the thoracic, thoracolumbar, and lumbosacral spine. METHODS: Patients with fracture, tumor, spondylolisthesis, spondylitis, failed back, or other degenerative conditions of the spine received the BWM instrumentation as described in the study literature and were regularly reviewed for 2 years. RESULTS: The results from the first 200 patients to complete the study showed an overall graft fusion rate of 94% (95% confidence interval: 91.3%-97.6%). There were marked improvements in measures of functional ability (P < 0.001, Wilcoxon test). Before surgery, less than half the patients were capable of outdoor activity. At 2 years, 80% were able to undertake outdoor activity. There were few perioperative difficulties reported. Postoperative complications associated with major surgery were seen in 18% patients. There were 23 (2.6%) pedicle screw failures, including two loosenings, and 13 (2.5%) spacer element failures, including three loosenings. CONCLUSIONS: Clinical failure was not necessarily a consequence of component failure. The BWM fixator provided excellent stabilization during the process of bone graft consolidation. The risks of complication or component failure were no higher than those associated with similar devices.

Morphometric analysis of vertebrae and intervertebral discs as a basis of disc replacement.

In this study measurements were obtained from 359 vertebrae and 215 intervertebral discs in an attempt to classify discs by their size. At the cervical and thoracic levels, this attempt was unproductive because of extensive variations. In the lumbar spine, discs were allocated to six size-matched groups and to two height-matched groups. The breadth of marginal rims were also measured with a view to provide surgeons operating on the spine with precise data on disc morphology to facilitate disc replacement.