[Minimally Invasive Posterior Lumbar Interbody Fusion and Instrumentation - Outcomes at 24-Month Follow-up]. / Minimálne invazivní zadní mezitelová fúze a instrumentace ­ výsledky po 24 mesících sledování.

PURPOSE OF THE STUDY Minimally invasive posterior lumbar interbody fusion and percutaneous instrumentation were introduced in the clinical practice with the aim to reduce the damage to musculoligamentous structures associated with open surgeries. The purpose of the study is to evaluate the clinical outcomes, radiological results and complications of the group of patients operated with the use of the minimally invasive posterior lumbar interbody fusion technique. MATERIAL AND METHODS The group of 31 patients operated for lumbar degenerative disc disease was followed-up prospectively. The surgical technique included a unilateral microsurgical decompression of the spinal canal with the insertion of interbody cages supplemented by percutaneous transpedicular fixation. The clinical outcomes were evaluated by means of the Oswestry Disability Index (ODI), Macnab classification, VAS score for low back pain (VAS LBP) and lower extremity pain (VAS LE) at 2, 6, 12 and 24 months postoperatively. The success rate of interbody fusion and complications was also assessed. RESULTS The inclusion criteria were met by 29 patients. The mean preoperative ODI score of 68.4 decreased to 25.1 at two-year follow-up (p 0.001). Based on the modified Macnab scale excellent and good outcomes were achieved at two-year-followup by 82.4% patients. The mean value of VAS LBP score decreased from 6.2 to 2.1 and in case of VAS LE from 5.38 to 1.34 (p ˂ 0.001). The mean time of operation was 157 minutes. Solid interbody fusion was achieved in 80% of patients. In one case, revision surgery for dislocation of the interbody cage was performed one year after the operation. A total of five misplaced transpedicular screws (5.2%) were recorded. DISCUSSION Dorsal minimally invasive spinal operational techniques, when compared with the open surgery, result in less iatrogenic injury to paravertebral muscles. From a short-term perspective, there is also less blood loss and lower frequency of infectious complications. Together with the reduction of postoperative pain and shorter hospital stay, they enable faster recovery and rehabilitation with comparable clinical effectiveness of the procedure. Apart from the above-mentioned benefits, also some shortcomings are discussed such as higher frequency of complications, longer time of operation, higher occurrence of implant malposition and higher exposure of the patient and the surgeon to radiation. CONCLUSIONS The minimally invasive posterior lumbar interbody fusion technique resulted in a statistically significant clinical improvement in the ODI, Macnab scale, VAS LBP and VAS LE scores. The percutaneous instrumentation technique shows an acceptable rate of incorrectly inserted screws. Key words: degenerative disc disease, minimally invasive spinal surgery, posterior lumbar interbody fusion, spine stabilization, lumbar interbody fusion complications.

[First Experience with Cranioplasty Using the Polyetheretherketone (PEEK) Implant - Retrospective Five-Year Follow-up Study]. / První zkusenosti s kranioplastikou pomocí implantátu z polyetereterketonu (PEEK) ­ retrospektivní studie pri petiletém sledování.

PURPOSE OF THE STUDY Cranioplasty is currently the most common neurosurgical procedure. The purpose of this study is to describe the first experience with successful use of the Cranio-Oss (PEEK) custom implant for cranioplasty. MATERIAL AND METHODS In the period 2012 to 2013, a total of 26 cranioplasties were performed. In fourteen patients, their own bone flap was used for reconstruction. In four cases, a synthetic Cranio-Oss bone implant made of PEEK was used. In six patients, the defect was covered by an intraoperatively-made Palacos implant and in two cases, minor defects were covered with a titanium mesh. The patients were followed up for at least five years. Cranio-Oss is a cranial implant made from polyetheretherketone (PEEK), a synthetic biocompatible material. The implant is created using the CAD/CAM method in the shape of the bone defect based on the CT scan. Creating optimal roughness of the implant surface and of the surface of the contact area attached to the bone bed is controlled and included already in the strategy for machining individual areas of the implant during its manufacturing at a 5-axis machining centre. RESULTS The Cranio-Oss implant was used in four younger patients to cover larger and complex-shaped defects. The mean age of patients in this group was 47 years. The implant was fixed to the skull by micro-plates. In all the cases the wound healed well with good cosmetic results without the necessity of revision with respect to the used implant. The follow-up CT scans always showed the implant in situ with no signs of malposition. DISCUSSION Autologous bone flap is the most suitable material for defect reconstruction after craniectomy. This option is affordable and represents one of the best methods of reconstruction of defects after craniectomy in terms of cosmetic results. In some cases, the original skull cannot be used for cranioplasty (e.g. if destructed by tumourous process, infected or in comminuted fractures). In such cases, the defect needs to be managed using a synthetic implant. In case of extensive defects, the most suitable option is a custom made implant from advanced biomaterials. CONCLUSIONS Authors prefer using autologous bone flaps during cranioplasty. In cases where this method is unavailable, a synthetic bone substitute has to be used. The first medium-term experience with the use of a Cranio-Oss implant made of PEEK showed that it is a suitable alternative to the patient's own bone. No complications associated with this synthetic implant were reported and its use to manage skull defects can be strongly recommended. With respect to legal and accreditationrelated difficulties connected with bone fragments storage and thanks to the continuous cost reduction of synthetic implants will their importance grow in the future. Key words: decompressive craniectomy, bone substitute, craniotrauma.

Immunohistochemistry and serum values of S-100B, glial fibrillary acidic protein, and hyperphosphorylated neurofilaments in brain injuries.

INTRODUCTION: Traumatic brain injury (TBI) triggers a series of reactions resulting in cytoskeletal-related changes varying between focal and diffuse injuries. METHODS: The patients (n=38) were divided into group of diffuse axonal injuries (DAI, n=10) and focal (n=28) injuries. Serum hyperphosphorylated neurofilaments (NF-H) and glial fibrillary acidic protein (GFAP) were measured by Biovendor immunoassay, and serum S-100B protein was measured by Cobas e411 (Roche) by immunoassay. Immunohistochemistry was performed with monoclonal antibodies (Chemicon, USA). RESULTS: The median serum S-100B concentration was higher in patients with focal mass lesions (1.72±0.4 µg/l vs. 0.37±0.1 µg/l, p<0,05) compared to patients with DAI during 10 days of hospitalisation. With respect to all patients, the highest peak of serum S-100B values (4.21±1.1 µg/l) and GFAP (8.58±2.4 µg/l) were found in expansive lesions. The median serum NF-H was higher in DAI compared to focal TBI (0.625±0.14 vs 0.139±0.02 ng/l, p<0.05) during all 10 days after admission. Further, immunohistochemical investigation, in deceased patients with DAI , using NF-H antibody proved positive varicose and waving axons, and retraction balls. Time-dependent profile of serum NF-H demonstrated the increase of values within 4th up to 10th day in both groups. Values ranged from 0.263 up to 1.325 ng/l in DAI, and from 0.103 up to 1.108 ng/l in focal injuries. Patients with expansive contusions had similar levels of serum NF-H as patients without expansive lesions. Immunohistochemistry of cytoskeletal proteins presented strong positive staining of vinculin, vimentin in vessels, GFAP, and S-100B in DAI compared to weak staining in expansive lesions. CONCLUSION: The time-profile kinetics of all markers may reflect different types of pathophysiological changes of the BBB or axonal damage in focal and diffuse injuries. KEYWORDS: brain contusions - diffuse axonal injury - S-100B protein - GFAP - hyperphosphorylated neurofilaments.

[Verification of a surgical technique using a new biotitanium cage in degenerative diseases of the lumbar spine--experimental study]. / Overení operacní techniky pomocí nové biotitanové cage u degenerativního onemocnení bederní pátere--experimentální práce.

PURPOSE OF THE STUDY: Authors performed experimental PLIF operations on cadavers to verify appropriate shape and size of cage made from bioactive titan material. The approach for application into intervertebral space of the lumbar spine and appearance on X-ray and CT scans was also investigated. MATERIAL: In experiment on cadavers five implantations of interbody cages were performed, two of them in interbody space L3/L4 and three of them in L4/L5. Subtotal discectomy and end platec preparation was done before cage insertion. Our type of cage is made from bioactive titan material and fastened in the application instrument that we developed for this purpose. METHOD: To verify operational approach we used midline incision and opened spinal canal through laminectomy, partial hemilaminectomy or partial medial facetectomy. This phase was followed by discectomy and end plates preparation. Stability of inserted cages in intervertebral space is ensured by rotation and anchorage of cage wings in end plates. Operated motion segment was taken out and evaluated by X-rays and CT scans. RESULTS: The operational approach through partial hemilaminectomy and partial medial facetectomy was fully sufficient for cage application with respect to operated segment. All implantations were successful and position of cages satisfactory. Thanks to less robust gripping instrument the approach was more thrifty compared to glass-ceramic cage and comparable with commercially produced cages that we have experience with (Spine Tech, Stryker, Comesa). Due to cage radio opaque, proper position of cages is easy to control on X-ray and CT scans and allows good peroperative monitoring by X-ray magnifier. DISCUSSION: Usage of bioactive materials in spinal surgery started by introduction of glass ceramics. Based on our experience we determined suitable indications. To eliminate some of te disadvantages of glass ceramics (mainly mechanical properties), a cage made from bioactive material was developed. This type of cage does not require bone harvesting to fill the cage. This fact results in better comfort for patient in postoperative period and eliminates complications from bone graft harvesting. Bioactive surface of the cage with osseo conductive and osseo integrative features creates prerequisites for solid fusion without bone grafts. Titanium material guarantees mechanical strength and makes possible to produce a wide range of shapes and sizes. Strength of the material enables more advantageous gripping of cage in application instrument. The cage is well visible on X-ray and in MRI scans artifacts are considerably reduced. Operational approach and technique are similar to other commercially produced cages and the extent of destabilization is limited to minimum. CONCLUSION: Experimentally we repeatedly verified operational approach, suitable shape and applicability of bioactive titanium cage into intervertebral space. For clinical use bioactive titanium could be a possible way how to replace bone grafts. For spinal surgeons it represents a chemically and mechanically stable material capable of interaction in an environment where it is implanted. Even in difficult conditions the level of osseo integration is high.