[Surgical Treatment of Degenerative Lumbar Stenosis and Spondylolisthesis: Clinical Practice Guideline]. / Chirurgická lécba degenerativní lumbální stenózy a spondylolistézy: klinický doporucený postup.

PURPOSE OF THE STUDY This article presents the evidence and the rationale for the recommendations for surgical treatment of degenerative lumbar stenosis (DLS) and spondylolisthesis that were recently developed as a part of the Czech Clinical Practice Guideline (CPG) "The Surgical Treatment of the Degenerative Diseases of the Spine". MATERIAL AND METHODS The Guideline was drawn up in line with the Czech National Methodology of the CPG Development, which is based on the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. We used an innovative GRADE-adolopment method that combines adoption and adaptation of the existing guidelines with de novo development of recommendations. In this paper, we present three adapted recommendations on DLS and a recommendation on spondylolisthesis developed de novo by the Czech team. RESULTS Open surgical decompression in DLS patients has been evaluated in three randomized controlled trials (RCTs). A recommendation in favour of decompression was made based on a statistically significant and clinically evident improvement in the Oswestry Disability Index (ODI) and leg pain. Decompression may be recommended for patients with symptoms of DLS in the event of correlation of significant physical limitation and the finding obtained via imaging. The authors of a systematic review of observational studies and one RCT conclude that fusion has a negligible role in the case of a simple DLS. Thus, spondylodesis should only be chosen as an adjunct to decompression in selected DLS patients. Two RCTs compared supervised rehabilitation with home or no exercise, showing no statistically significant difference between the procedures. The guideline group considers the post-surgery physical activity beneficial and suggests supervised rehabilitation in patients who have undergone surgery for DLS for the beneficial effects of exercise in the absence of known adverse effects. Four RCTs were found comparing simple decompression and decompression with fusion in patients with degenerative lumbar spondylolisthesis. None of the outcomes showed clinically significant improvement or deterioration in favour of either intervention. The guideline group concluded that for stable spondylolisthesis the results of both methods are comparable and, when other parameters are considered (balance of benefits and risks, or costs), point in favour of simple decompression. Due to the lack of scientific evidence, no recommendation has been formulated regarding unstable spondylolisthesis. The certainty of the evidence was rated as low for all recommendations. DISCUSSION Despite the unclear definition of stable/unstable slip, the inclusion of apparently unstable cases of DS in stable studies limits the conclusions of the studies. Based on the available literature, however, it can be summarized that in simple degenerative lumbar stenosis and static spondylolisthesis, fusion of the given segment is not justified. However, its use in the case of unstable (dynamic) vertebral slip is undisputable for the time being. CONCLUSIONS The guideline development group suggests decompression in patients with DLS in whom previous conservative treatment did not lead to improvement, spondylodesis only in selected patients, and post-surgical supervised rehabilitation. In patients with degenerative lumbar stenosis and spondylolisthesis with no signs of instability, the guideline development group suggests simple decompression (without fusion). Key words: degenerative lumbar stenosis, degenerative spondylolisthesis, spinal fusion, Clinical Practice Guideline, GRADE, adolopment.

Imaging in gynecological disease (26): clinical and ultrasound characteristics of benign retroperitoneal pelvic peripheral-nerve-sheath tumors.

OBJECTIVE: To describe the clinical and sonographic characteristics of benign, retroperitoneal, pelvic peripheral-nerve-sheath tumors (PNSTs). METHODS: This was a retrospective study of patients with a benign, retroperitoneal, pelvic PNST who had undergone preoperative ultrasound examination at a single gynecologic oncology center between 1 January 2018 and 31 August 2022. All ultrasound images, videoclips and final histological specimens of benign PNSTs were reviewed side-by-side in order to: describe the ultrasound appearance of the tumors, using the terminology of the International Ovarian Tumor Analysis (IOTA), Morphological Uterus Sonographic Assessment (MUSA) and Vulvar International Tumor Analysis (VITA) groups, following a predefined ultrasound assessment form; describe their origin in relation to nerves and pelvic anatomy; and assess the association between their ultrasound features and histotopography. A review of the literature reporting benign, retroperitoneal, pelvic PNSTs with preoperative ultrasound examination was performed. RESULTS: Five women (mean age, 53 years) with a benign, retroperitoneal, pelvic PNST were identified, four with a schwannoma and one with a neurofibroma, of which all were sporadic and solitary. All patients had good-quality ultrasound images and videoclips and final biopsy of surgically excised tumors, except one patient managed conservatively who had only a core needle biopsy. In all cases, the findings were incidental. The five PNSTs ranged in maximum diameter from 31 to 50 mm. All five PNSTs were solid, moderately vascular tumors, with non-uniform echogenicity, well-circumscribed by hyperechogenic epineurium and with no acoustic shadowing. Most of the masses were round (n = 4 (80%)), and contained small, irregular, anechoic, cystic areas (n = 3 (60%)) and hyperechogenic foci (n = 5 (100%)). In the woman with a schwannoma in whom surgery was not performed, follow-up over a 3-year period showed minimal growth (1.5 mm/year) of the mass. We also summarize the findings of 47 cases of benign retroperitoneal schwannoma and neurofibroma identified in a literature search. CONCLUSIONS: On ultrasound examination, no imaging characteristics differentiate reliably between benign schwannomas and neurofibromas. Moreover, benign PNSTs show some similar features to malignant retroperitoneal tumors. They are solid lesions with intralesional blood vessels and show degenerative changes such as cystic areas and hyperechogenic foci. Therefore, ultrasound-guided biopsy may play a pivotal role in their diagnosis. If confirmed to be benign PNSTs, these tumors can be managed conservatively, with ultrasound surveillance. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Surgical treatment of cervical spine fractures in ankylosing spondylitis patients: posterior stabilization using intraoperative CT scanner-based navigation.

INTRODUCTION: The authors analyzed a series of ankylosing spondylitis patients with cervical spine fracture undergoing posterior stabilization using spinal navigation based on intraoperative CT imaging. The purpose of this study was to evaluate the accuracy and safety of navigated posterior stabilization and to analyze the adequacy of this method for treatment of fractures in ankylosed cervical spine. METHODS: Prospectively collected clinical data, together with radiological documentation of a series of 8 consecutive patients with 9 cervical spine fracture were included in the analysis. The evaluation of screw insertion accuracy based on postoperative CT imaging, description of instrumentation-related complications and evaluation of morphological and clinical results were the subjects of interest. RESULTS: Of the 66 implants inserted in all cervical levels and in upper thoracic spine, only 3 screws (4.5%) did not meet the criteria of anatomically correct insertion. Neither screw malposition nor any other intraoperative events were complicated by any neural, vascular or visceral injury. Thus we did not find a reason to change implant position intraoperatively or during the postoperative period. The quality of intraoperative CT imaging in our group of patients was sufficient for reliable trajectory planning and implant insertion in all segments, irrespective of the habitus, positioning method and comorbidities. In addition to stabilization of the fracture, the posterior approach also allows reducing preoperative kyphotic position of the cervical spine. In all patients, we achieved a stable situation with complete bone fusion of the anterior part of the spinal column and lateral masses at one year follow-up. CONCLUSION: Spinal navigation based on intraoperative CT imaging has proven to be a reliable and safe method of stabilizing cervical spine with ankylosing spondylitis. The strategy of posterior stabilization seems to be a suitable method providing high primary stability and the conditions for a subsequent high fusion rate.

Instrumentation of C1 lateral mass via insertion of the posterior arch of atlas - a morphometric study.

INTRODUCTION: Instrumentation of the lateral mass of atlas via posterior arch attachment (PALMS) is a method that, unlike the traditional direct screw insertion into the lateral mass, prevents damage to the periarticular venous plexus and C2 nerve root. The method itself may be, however, limited by the anatomical situation. The small cranio-caudal pedicle dimension may lead to vertebral artery damage. The aim of this study was to use morphometric examination of CT findings from the healthy population to evaluate theoretical feasibility of this technique in a randomly selected population sample. METHODS: Morphometric measurements determining dimensions of C1 pedicle at the site of expected screw insertion were performed on reformatted parasagittal CT scans of 42 healthy probands. Using the software of the Jivex browser, we measured the minimum height of posterior arch insertion under the vertebral artery groove and evaluated the possibility of introducing 3.5 mm and 4 mm screws. RESULTS: The mean minimum height of the critical segment was calculated as 4.29 mm (left insertion 4.28 mm, right insertion 4.31 mm, range 3.02-5.62 mm). Despite the highest size in a female and the lowest in a male, the male population showed larger bone stock (mean of 4.71 mm: left connection 4.70 mm, right connection 4.71 mm) than the female one (mean of 4.29 mm: left 4.28 mm, right 4.31 mm). Overall, we found 59.5% insertions higher than 4 mm and 86.9% arch connections bigger than 3.5 mm. CONCLUSION: The anatomical situation allows inserting at least a 3.5mm diameter screw in a vast majority of cases. The posterior arch attachment point thus seems to be a suitable anatomical target for instrumentation of C1 lateral mass. Nevertheless, individual presurgical planning and intraoperative spinal navigation should be implemented, as well.

[Odontoid bending stiffness after anterior fixation with a single lag screw: biomechanical study]. / Ohybová tuhost zubu cepovce po prední fixaci jedním tahovým sroubem - biomechanická studie.

PURPOSE OF THE STUDY The aim of the experiment was to compare the bending stiffness of an intact odontoid process with bending stiffness after its simulated type II fracture was fixed with a single lag screw. The experiment was done with a desire to answer the question of whether a single osteosynthetic screw is sufficient for good fixation of a type II odontoid fracture. MATERIAL AND METHODS The C2 vertebrae of six cadavers were used. With simultaneous measurement of odontoid bending stiffness, the occurrence of a fracture (type IIA, Grauer's modification of the Anderson- D'Alonzo classification) was simulated using action exerted by a tearing machine in the direction perpendicular to the odontoid axis. Each odontoid fracture was subsequently treated by direct osteosynthesis with a single lag screw inserted in the axial direction by a standard surgical procedure in order to provide conditions similar to those achieved by routine surgical management. The treated odontoid process was subsequently subjected to the same tearing machine loading as applied to it at the start of the experiment. The bending stiffness measured was then compared with that found before the fracture occurred. The results were statistically evaluated by the t-test for paired samples at the level of significance α = 0.05. RESULTS The average value of bending stiffness for odontoid processes of intact vertebrae at the moment of fracture occurrence was 318.3 N/mm. After single axial lag screw fixation of the fracture, the average bending stiffness for the odontoid processes treated was 331.3 N/mm. DISCUSSION Higher values of bending stiffness after screw fixation were found in all specimens and, in comparison with the values recorded before simulated fractures, the increase was statistically significant. CONCLUSIONS The results of our measurements suggest that the single lag screw fixation of a type IIA odontoid fracture will provide better stability for the fracture fragment-C2 body complex on antero-posterior perpendicular loading than can be found in intact C2 vertebrae. Key words: odontoid fracture, odontoid fixation, bending stiffness, lag screw.

[The angular profile of a cage has no influence on segmental alignment after anterior cervical stand-alone interbody fusion]. / Úhlový profil kose neovlivní segmentální postavení pri prední krcní fúzi provedené metodou stand-alone.

PURPOSE OF THE STUDY: The original aim of this prospective semi-randomised study was to determine associations between segmental sagittal alignment after Anterior Cervical Discectomy and Fusion (ACDF) and subjective and clinical results. Two types of cages, cage P with parallel end-plates and cage A with 5-degree angulations, were used in the patients treated for degenerative conditions. MATERIAL AND METHODS: A total of 94 consecutive patients, 56 treated by single-level ACDF and 38 undergoing a two-level procedure, completed 8 years of follow-up. The patients in equally-sized A and P subgroups were examined at 6 weeks and 1, 2 and 8 years after surgery. The follow-up included X-ray in a neutral lateral position, a questionnaire assessing pain in neck and shoulder regions and JOA scores. The results including the cumulative incidence of surgical procedures indicated for adjacent segment diseases were statistically evaluated. RESULTS: An average increase in the lordotic angle at 6 weeks after surgery was 2.32° for the implant P and 2.02° for the implant A subgroup. During 8 years of follow-up the average values decreased to 1.51° and 1.36°, respectively. The proportion of patients with no or minimal neck and shoulder pain decreased, in subgroup P, from the initial 85% at 6 weeks to 59% at 8 years after the surgery and, in subgroup A, from 89% to 40 %. The average JOA score of 16 at 6 weeks in both subgroups, at 8 years, had a value of 15.9 in subgroup P and 16.0 in subgroup A. The cumulative incidence of surgery for adjacent segment disease 8 years was 8.3% for subgroup P and 6.3% for subgroup A. No statistically significant differences between the subgroups at any follow-up period were recorded in either morphological characteristics or clinical outcomes. CONCLUSIONS: The ability to lordotize a segment by stand-alone ACDF is below the angular resolution of current radiographic methods, irrespective of the sagittal profile of the implant used. Comparable morphological results haven´t been reflected by significant difference in subjective and clinical outcome and also in the incidence of surgery for adjacent segment disease. Such results were not expected and therefore post-operative sagittal alignment mechanisms in stand-alone cage assisted ACDF will require further investigation. Key words:cervical vertebrae, surgical technique, spinal fusion, sagittal alignment, clinical outcome.

[Intraoperative CT-based spinal navigation: the initial 295 implants experience]. / Navigace v páterní chirurgii zalozená na intraoperacním CT zobrazení: zkusenost s iniciálními 295 implantáty.

INTRODUCTION: The authors describe the system of spinal navigation based on intraoperative CT imaging and the results of an initial series of patients. MATERIAL AND METHODS: Spinal screws inserted during 50 surgical procedures in the period between November 2012 and October 2013 were evaluated for insertion accuracy, intraoperative complications and the accessibility of the method for the selected spinal level. RESULTS: Out of the total of 295 screws inserted throughout all the spinal levels from C0 to S1, only 4 (1.3%) pedicle screws were found to be incorrectly inserted: a single L5 screw breached the lower cortex of the pedicle, two thoracic pedicular screws penetrated the anterior margin of the vertebral body not exceeding 3 mm of the shaft length, and a single C3 pedicle screw penetrated the upper vertebral body end-plate. None of these complications caused morbidity or required re-operation. Intraoperative CT imaging together with the navigation procedure increased the time of surgery by 30 minutes on average and patient radiation exposure during the initial and accuracy control CT scan was increased. CONCLUSION: Our initial experience has shown that the CT-based computer-assisted spinal navigation system is a precise surgical modality. It enables higher accuracy in spinal screw positioning, resulting in lower surgical morbidity and increased safety for the patient. This benefit should outweigh the longer operation time as well as a higher radiation exposure of the patients.

[Odontoid fracture combined with lateral atlanto-axial dislocation. Report of two cases]. / Zlomenina zubu cepovce II. typu spojená s laterální dislokací atlasu. Popis dvou prípadu.

The authors describe their experience with treatment of two neurologically intact male patients, aged 70 and 74 years, presenting with combined lateral atlanto-axial dislocation and odontoid type II fracture. The mechanism of these two craniovertebral junction injuries had been lateroflexion of the neck. The initial attempt at closed reduction using axial traction failed. The authors succeeded with a closed reduction maneuver under general anaesthesia in the first patient in whom long-term stability was achieved by transarticular C2-C1 fixation, together with interlaminar fusion. In the second patient, closed reduction was unsuccessful due to intra-articular soft tissue interposition. Release and reduction were achieved by instrumentation of C1 lateral masses and transpedicular anchorage of screws into the C2. The subsequent Harms C1-C2 stabilisation proved to be effective both in achieving long-term stability and segmental fusion of lateral masses. Aspects of biomechanics as well as a review of pertinent literature are presented.

[Timing of surgical intervention in acute spinal cord injury and post-operative neurological recovery]. / Timing operací pátere pri akutním poskození míchy a jeho vliv na vývoj neurologického nálezu.

PURPOSE OF THE STUDY: The effect of an early surgical intervention in the traumatised spine on resolution of neurological deficit still remains a topic of professional discussions. The aim of this retrospective study was to find a correlation between the length of an injury-to-surgery interval and the development of a post-operative neurological deficit, and thus to answer the question of whether early surgical decompression and stabilization gives better chance of neurological recovery. MATERIAL AND METHODS: Medical records of consecutive surgical patients admitted between 2007 and 2010 with traumatic spinal cord injury were reviewed and the injury-to-surgery interval and post-operative development of neurological deficit at a minimum follow-up of 6 months was evaluated. The initial neurological finding and the finding at 6 months of follow-up were classified on the Frankel scale and the outcome was assessed as improved or unimproved. The patients were allocated to four subgroups according to the time that elapsed between injury and surgery, i.e., time up to 24 h, 24-72 h, 72 h -1 week, and longer than 1 week. The percentage of improved patients was calculated in each subgroup and the results were statistically evaluated using the Kruskal-Wallis test at a significance level of 0.1. RESULTS: Out of the total number of 32 evaluated patients, 28 had at least partial neurological recovery. In the subgroup treated within first 24 h, improvement was found in 93 % of the patients, in the 24-72 h subgroup it was 80%, in the 72 h-1 week subgroup it was 60% and surgery later than a week after injury resulted in improvement in 42% of the patients. Based on statistical evaluation, the time between injury and surgery appeared to be a significant prognostic factor. When a paired comparison of subgroups was made, the only significant difference was found between the subgroup treated within 24 hours of injury and that operated on later than a week after injury. The other paired comparisons failed to show a significant difference due to a small number of patients; however, a tendency to better functional results was observed in all earlier- treated subgroups. DISCUSSION: The authors are aware of few limitations of the study. Its retrospective character, a relatively small number of patients and a single institution setup may limit the interpretation. Despite this fact, the message is clear. Similar studies carried out prospectively at several institutions may, however, provide results with a higher validity. CONCLUSIONS: Patients with traumatic spinal cord injury who undergo early decompression and stabilisation have a higher chance of at least partial neurological recovery.

[Current role of methylprednisolone in the treatment of acute spinal cord injury]. / Soucasný pohled na uzívání methylprednisolonu v lécbe akutního poskození míchy.

High doses of methylprednisolone (MPSS) came into use as part of a therapeutic protocol for acute spinal cord injuries following the published results from the NASCIS II study in 1992; they soon became a standard of care around the world. However, the results of this study have been critically reviewed and questioned by many authors since the beginning. The major argument is based on the fact that its effectiveness in reducing post-injury neurological damage has not been conclusively proved; in addition, there has been increasing evidence of serious side effects of steroids administered at high doses. In the Czech Republic, as part of pre-hospital care, MPSS according to the NASCIS II (or NASCIS III) protocol is used in all regional centres of emergency medical service. In the Czech spinal surgery centres involved in treating acute spinal cord injuries, there are 19 of them, attitudes towards the use of MPSS vary. In 16% of the centres a certainty of its beneficial effect is still maintained, faith in its effect together with fear of a "non-lege artis" procedure is the reason for MSPP use in 21%, and the fear of sanctions only leads to its use in 63% of the centres. There is no standard practice in application of the NASCIS II and NASCIS III protocols and no standard exclusion criteria exist. The two protocols are used equally, and one institution has its own modification. The recommended MPSS dose is administered with no exception in 63% of the centres; dose adjustment is employed according to the form of spinal cord lesion in 11%, the level of spinal cord injury in 5%, associated diseases in 16% and patient age in 11% of the spinal surgery centres. After the results of studies on MPSS administration in acute spinal cord injury have been analysed, many medical societies have changed their recommendations. In view of later relevant publications it is no longer possible to regard MPSS administration as a standard of cure for acute spinal cord injury. Current evidence suggests that MPSS administration in a 24-hour regimen after an initial dose given within 8 hours of injury is the therapeutic procedure that needs individual consideration in each patient according to their state of health and potential complications. MPSS administration at an interval longer than 8 hours after injury and for more than 24 hours is not justified, nor is it justified to use a high MPSS dose at the place of injury by an emergency ambulance crew. Key words: corticosteroids, methylprednisolone, spinal cord trauma, neurological damage.

[Mathematical simulation of biomechanical background of osteophyte formation in cervical vertebra]. / Matematický model biomechanického pozadí osteodegenerativního procesu krcního obratle.

PURPOSE OF THE STUDY: The aim of this study was to simulate different types of cervical vertebra loading and to find out whether mechanical stress would concentrate in regions known in clinical practice as predilection sites for osteophyte formation. The objective was to develop a theoretical model that would elucidate clinical observations concerning the predilection site of bone remodelling in view of the physiological changes inside the cervical vertebral body. MATERIAL AND METHODS: A real 3D-geometry of the fourth cervical vertebra had been made by the commercially available system ATOS II. This is a high-resolution measuring system using principles of optical triangulation. This flexible optical measuring machine projects fringe patterns on the surface of a selected object and the pattern is observed with two cameras. 3D coordinates for each camera pixel were calculated with high precision and a polygon mesh of the object's surface was further generated. In the next step an ANSYS programme was used to calculate strains and stresses in each finite element of the virtual vertebra. The applied forces used in the experiment corresponded in both magnitude and direction to physiological stress. Mechanical loading in neutral position was characterized by a distribution of 80% mechanical stress to the vertebral body and 10% to each of the zygoapophyseal joints. Hyperlordotic loading was simulated by 60% force transfer to the vertebral body end-plate and 20% to each of the small joint while kyphotic loading involved a 90% load on the vertebral body endplate and 5% on each facet. RESULTS: Mechanical stress distribution calculated in a neutral position of the model correlated well with bone mineral distribution of a healthy vertebra, and verified the model itself. The virtual mechanical loading of a vertebra in kyphotic position concentrated deformation stress into the uncinate processes and the dorsal apophyseal rim of the vertebral body. The simulation of mechanical loading in hyperlordosis, on the other hand, shifted the region of maximum deformation into the articulation process of the Z-joint. All locations are known as areas of osteophyte formation in degenerated cervical vertebrae. DISCUSSION AND CONCLUSIONS: The theoretical model developed during this study corresponded well with human spine behaviour in terms of predilection sites for osteodegenerative changes, as observed in clinical practice. A mathematical simulation of mechanical stress distribution in pre-operative planning may lead to the optimisation of post-operative anatomical relationship between adjacent vertebrae. Such improvement in our surgical practice may further reduce the incidence of degenerative changes in adjacent motion segments of the cervical spine and possibly also lead to better subjective and clinical results after cervical spine reconstruction.

[Solitary spinal osteochondroma. Case report]. / Solitární páterní osteochondrom diagnostikovaný u 75letého muze.

Spinal osteochondromas as solitary lesions are rare tumours of a maturing adolescent skeleton. The authors treated a 75-year-old man for low back pain and neurogenic claudication. Symptoms were attributed to a tumorous expansion originating from the spinous process and right lamina of L3 and expanding into the spinal canal and adjacent facet joints. The patient underwent marginal resection of the tumour together with transpedicular stabilization of the segment, and histological examination confirmed the diagnosis of osteochondroma. The patient remains without any complaint and there are no signs of local recurrence of the tumour 4 years after the surgery. The cases of osteochondroma in an aged spine published in the literature and pertinent aspects of this extremely rare condition are discussed. Key words: spinal tumors, osteochondroma.

Exophytic intramedullary mature teratoma of the conus medullaris: case report and review of the literature.

BACKGROUND: Intramedullary tumors affect a small but significant portion of patients with spinal tumors. Ependymomas and astrocytomas are the most common entities. The diagnosis of a mature teratoma is extremely rare, although not in the presence of associated developmental abnormalities. The medullary conus is the most common location. Such a case with caudal exophytic growth is presented here and the literature extensively reviewed. CASE PRESENTATION: Low back pain and muscle weakness led to diagnosis of a exophytic intramedullary lesion of the conus medullaris in a 52-year-old woman. After subtotal resection the symptomatology partially improved. Histopathological examination revealed mature teratoma. CONCLUSION: Literature review identified 68 cases of intramedullary teratomas. These should be considered in the differential diagnosis when an associated developmental abnormality is present. Subtotal resection is a valid alternative to radical tumor removal when neurological function is at risk. The prognosis of adult patients with intramedullary mature teratoma is excellent.

[Navigation techniques in surgery of cranio-cervical junction and upper cervical spine]. / Navigacní techniky v chirurgii kraniocervikálního prechodu a horní krcní pátere.

Spinal navigation has substantially advanced during the past ten years. Surgeons have gained sufficient skills and confidence, and have introduced this technology to the anatomically challenging region of the upper cervical spine and craniocervical junction. The detailed evaluation of individual anatomy, rational pre-operative planning and final intraoperative control improve the safety and precision of classical surgical procedures. As methods technologically evolve, indication criteria change accordingly, but the basic principles of a relevatn choice remain; these are to reduce morbidity due to its three main causes, i.e., mechanical, neurological and vascular. We present an overview of current techniques and discuss their applicability in the region of the upper cervical spine and craniocervical junction. The systems allowing us to obtain live images intra-operatively, such as fluoroscopy or intra.operative CT, seem to be most versatile and accurate, especially when combined with traditional virtual navigation systems. Based on case histories, the authors suggest trends in the development of this field, with a focus on minimally invasive techniques. Key words: navigation, upper cervical spine, craniocervical junction.

[Percutaneous CT-guided radiofrequency ablation in spinal osteoid osteoma treatment]. / Perkutánní CT-navigovaná radiofrekvencní ablace v terapii spinálních osteoidních osteomu

PURPOSE OF THE STUDY: Radiofrequency ablation is a minimally invasive method indicated in the treatment of bone tumors. Its effectiveness and safety have been reported in a number of studies concerned with the therapy of osteoid osteoma of extremities. However, only scarce information is available on effectiveness of ablation in osteoid osteoma of the spine. The aim of the study was to verify the efficacy of percutaneous CT-guided radiofrequency ablation on this indication. MATERIAL AND METHODS: This prospective study included four patients, three women and one man, with osteoid osteoma of the lumbar or sacral spine who were treated by percutaneous CT-guided radiofrequency ablation in the period from February 2002 to March 2005. Two tumors were found in the third lumbar vertebra, one in the fourth lumbar and one in the first sacral verstebra. The pre-operative pain values assessed on the visual analogue scale (VAS), and function restriction rated by the Oswestry Disability Index (ODI) were compared with the post-operative values at 2 years after surgery. Patients' satisfaction with surgical outcome was evaluated according to Odom's criteria. RESULTS: All four procedures were accomplished successfully in technical terms and the patients completed the two-year followup. All patients reported significant relief of pain immediately after surgery and this held even after 2 years. The average pre-operative VAS value of 8.3 was reduced to 2.45 at the final examination, and the pre-operative ODI of 70/100 improved to 95/100 post-operatively. The outcome of treatment rated by Odom's criteria was regarded as excellent. CONCLUSIONS: Percutaneous CT-guided radiofrequency ablation is an effective and safe method for treatment of spinal osteoid osteoma. It has advantages that could make it preferable to surgical excision of tumors. Key words: osteoid osteoma, computed tomography, radiofrequency ablation.

[Surgical treatment of fracture of the ring of axis - "hangman's fracture"]. / Chirurgické resení fraktury oblouku epistrofeu - "katovské zlomeniny".

PURPOSE OF THE STUDY: To evaluate surgical management of the fracture of the ring of axis (FRA), known as "hangman's fracture", and to discuss adequacy of this treatment. MATERIAL AND METHODS: Between 1994 and 2004, 41 patients with FRA were surgically treated in our hospital. We present a retrospective study of 30 cases treated by anterior cervical fixation and fusion and 11 cases treated by a posterior, CT-guided approach (published recently). Our diagnostic algorithm for evaluation of FRA included plain radiographs for basic diagnosis, detailed CT scan, MRI and finally passive lateral flexion-extension fluoroscopy (performed by physician) to assess stability. We also consider discography in selected cases, allowing further evaluation of discoligamentous injury. Fractures were classified according to Levine. Posterior compressive osteosynthesis according to Judet was performed in 11 patients with Levine type I fractures with fracture fragment distraction > 3 mm. Anterior graft and plate fixation was chosen in 30 patients with type II (25 patients) and type I (5 patients) fractures where C2/3 disc injury was confirmed by MRI or discography. There was no case of facet dislocation in our series (type III). Pain, motion restriction and overall satisfaction with neck status were assessed on a scale 1-5 (1 = best) in patients treated with anterior approach. Self-evaluation questionnaires were administered during follow-up (average, 7.3 years; 24 months to 11 years). RESULTS: Anatomically reduced fracture fusion was achieved in all cases (100%) at one year follow-up. Both autologous tricortical (22) and fibular allografts (8) were used for anterior approach. No perioperative complications occurred and no case was aborted. Average hospital stay in patients with standalone FRA was 6.8 days (3-15). Patients wore Philadelphia collar for 4-6 weeks. One patient died during follow up due to unrelated causes. None of the 29 patients treated with the anterior approach reported severe or very severe pain (grades 4 or 5). The average pain score was 1.28. Three patients with isolated FRAs reported slight subjective restriction of movement (grade 2). The "satisfaction with overall neck status" scale showed an average score of 1.62, never worse than grade 2. DISCUSSION: Despite increasing popularity of anterior surgical approach in the treatment of type II FRA, most authors still recommend conservative treatment. Surgical treatment is consensually recommended in type III fractures only. Type I is treated exclusively conservatively. There is currently no evidence-based data supporting any method of treatment of so called "hangman's fracture". The majority of treating surgeons do not consider the status of the intervertebral disc. Dynamic films, simulating the peak point of injury, are usually not performed. Hence, potentially unstable fractures are overlooked. This also explains the lack of long term follow-up data regarding the radiological status of C2/3 intervertebral disc as well as patients' subjective complaints. CONCLUSIONS: Surgery provides plausible results. Compared to conservative treatment, it can offer significant benefits: 1) immediate, better and stable reposition; 2) high fusion rate; 3) shortening of the treatment period with better quality of life. Contrary to conservative treatment modalities, surgery possesses a potential for further development.

[Multiple-level instrumented anterior cervical fusion: a risk factor for pseudoarthrosis? A prospective study with a minimum of 3-year follow-up]. / Je víceetázová instrumentovaná prední krcní fúze rizikovým faktorem vzniku pseudoartrozy? Prospektivní studie s minimálne 3letou délkou sledování.

PURPOSE OF THE STUDY: This prospective study with minimal 3-year follow-up was performed to compare fusion rates, course of fusion, collapse incidence and occurrence of subsidence in one- and two-level instrumented anterior cervical fusions (ACDF) and thus to proof the hypothesis that use of internal fixation decreases the risk of non-union in bi-segmental ACDFs to the same level that can be expected in mono-segmental procedure. MATERIAL: In 79 consecutive patients operated upon by the Smith-Robinson technique for degenerative process of cervical spine in one or two levels was applied single instrumentation system in order to ensure ideal condition for solid bone fusion of 113 grafts (45 in one and 68 in two levels). All the patients were invariably followed for a minimum of 3 years. METHODS: Radiological criteria were used for evaluation of intervertebral fusion, graft collapse and its subsidence and results were statistically analyzed using M-L Chi-square test for the comparison of fusion and collapse incidence and further Chi-square test for the analysis of fusion course. All these figures were calculated at the level of significance 0.05 (alpha=0.05). RESULTS: Overall, no significant difference was observed in achieving solid bone fusion 3 years after the surgery in one- and two-level procedures (95.6% vers. 92.6%, p=0.522), neither the bone graft collapse rate was of significant difference (2.2% vers. 7.6%, p=0.208). In single-level group the time to bone fusion was significantly shorter (p<0.001). When pooling the data into autologous and allogenic graft subgroup, there was observed no statistically significant difference in achieving union in autologous subgroup (100% vers. 90.9%, p=0.142); in allogenic subgroup this situation was similar: no significant difference in fusion rate (93.3% vers. 93.5%, p=0.980) was observed. In both auto- and allogenic subgroups monosegmentally implanted grafts fused more readily (p<0.001). There was no case of graft subsidence in any investigated group. DISCUSSION: Our prospective study did not find any statistically significant difference in graft collapse and fusion rate when comparing one- and two-level instrumented ACDFs 3 years after the surgery. Plating system used in our patients brings more stability to operated segments and thus presumably prevents micromotions in postoperative period. Micromovements seems to be the major risk factor for non-union in non-instrumented multilevel cervical fusion. Other risk factor that should be considered in non-instrumented procedure is increase in compressive forces that are also partially eliminated by the semirigid internal fixation. Significantly delayed time to union observed in two level fusions shows most probably on increased number of surfaces that must be consolidated during the bone-healing process. CONCLUSION: This study demonstrates that internal fixation used in multilevel ACDF decreases risk of pseudoarthrosis to the same level that can be expected in monosegmental procedures.

[Traumatic spondylolisthesis of L5-S1]. / Traumatická spondylolistéza L5-S1.

Pure traumatic bilateral lumbosacral dislocation is a rare injury with just eight cases reported in the literature. This condition occurred also in 36-year-old man, who was struck into the lower back by a falling tree, during a woodcutting, at the moment when he was kneeling and his spine was flexed. Neurological examination showed no signs of spinal nerves injury. X-ray examination of the lumbosacral spine revealed the presence of a 40% anterior dislocation of L5 over S1 with locked facets and multiple fractures of transverse processes. Computer tomography confirmed these findings and also revealed massive medial L5-S1 disc herniation. Surgery performed 9 days after the injury consisted of L5 laminectomy, L5-S1 discectomy and segmental reduction and stabilization with transpedicular screws. Posterior lumbar interbody fusion was carried out using titanium PLIF-blocks. The patient healed without complications. At a 24-month follow-up he was without any subjective complaints, neurologically asymptomatic and without restriction of mobility in the lumbosacral spine. He was able to resume his previous work. This rare case is discussed in a view of the relevant literature, biomechanics of trauma and the appropriate therapy with an emphasis on open reduction and internal fixation techniques.

[Are screws in anterior cervical fusion with bicortical fixation truly inserted bicortically? Retrospective study]. / Jsou srouby pri prední krcní fúzi s bikortikální fixací skutecne bikortikálne zavedeny? (Retrospektivní studie).

PURPOSE OF THE STUDY: To examine the exact position of screws in anterior cervical fusion that were intended to be bicortically anchored at the time of surgery. MATERIAL: A randomly selected, representative sample (26) of our patient series undergoing anterior cervical fusion with bicortical screw fixation (250) during period of 1993-1999 is reviewed in this study with respect to an exact position of the tips of the screws to the posterior vertebral cortex. A total of 109 screws were assessed. METHODS: The position of 109 screws was assessed using an axial CT scan. On the basis of the distance of the screw tip from the posterior cortex of the vertebra, the screws were divided into several categories: mono- and bicortically anchored. Bicortically inserted screws were statistically evaluated using the confidence interval. RESULTS: Statistical analysis shows that the confidence interval of the screws being bicortically anchored lies between 66.7 and 87.5% (alpha value = 0.01). No screw was introduced more than 3 mm behind the posterior vertebral cortex. Monocortical introduction more than 1.5 mm in front of the cortex was observed in 7 screws (6.4%) in lower cervical spine and cervico-thoracic junction. DISCUSSION: All the screws that were classified as being too short were introduced in the cervico-thoracical junction or lower cervical spine known for its reduced X-ray transparency. The majority of screws, primarily described as bicortical, indeed penetrated both vertebral cortices. Considering the results of confidence interval for bicortical screw anchoring we conclude that 1 of 4 screws in monosegmental and 2 of 6 screws in bisegmental stabilization could fail to be bicortically inserted. CONCLUSION: [corrected] Intraoperative methods used for an accurate and safe bicortical screw insertion during anterior cervical fusion, i.e. intraoperative fluoroscopy, peak insertion torgue of the screw and the length measurement of the taped screw canal, are reliable enough to fulfill these goals.