Biomechanical stability analysis of transpedicular screws combined with sublaminar hook-rod system using the finite element method.

AIM: To develop and test a new posterior stabilization system by augmenting the posterior hook-rod system with screws and rods. METHODS: A biomechanical analysis was performed using the finite element method. The anatomical structures were modeled based on computed tomography data. Instrumentation (hooks, rods, and screws) was modeled based on the data obtained by 3D scanning. The discretized model was verified by converging solutions and validated against data from a previously published experiment. A Th12-L1 spinal segment was modeled and modified by removing the body of the L1 vertebra (corpectomy) and the entire L1 vertebra (spondylectomy). The model was additionally modified by incorporating stabilization systems: i) posterior stabilization (transpedicular screws and rods); ii) combined posterior stabilization with sublaminar hooks; and iii) combined anterior (titanium cage) and posterior (sublaminar hooks) stabilization. The rotation angles in each group, and the strains on each part of the three stabilization constructs, were analyzed separately. RESULTS: The combined anterior and posterior stabilization system was the stiffest, except in the case of lateral bending, where combined posterior stabilization was superior. Stress analysis showed that the posterior stabilization system was significantly unloaded when augmented with a hook-rod system. A significant strain concentration was calculated in the cranially placed hooks. CONCLUSION: Stiffness analysis showed comparable stiffness between the tested and proposed stabilization construct. Stress analysis showed luxation tendency of the cranially placed hooks, which would most likely lead to system failure.

Validation of the Croatian version of the Oswestry Disability Index.

PURPOSE: To translate, cross-culturally adapt, and validate the Croatian version of the Oswestry Disability Index (ODI). METHODS: The original English-language ODI was cross-culturally adapted into Croatian and then evaluated in a group of 114 patients with chronic low back pain (LBP) at the Department of Neurosurgery, Zagreb University School of Medicine. Confirmatory factor analysis (CFA) was conducted with three models: two were theory driven (unidimensional and two dimensional-static and dynamic factors); the other was based on our exploratory factor analysis (EFA). Internal consistency and test-retest reliability were evaluated using Cronbach's α and the intraclass correlation coefficient (ICC), respectively. Construct validity was assessed by evaluating the correlation between the ODI and Visual Analogue Scale (VAS), and between the ODI and 36-item short form survey (SF-36) scores. RESULTS: The EFA-derived two-dimensional structure explained 82.7% of the total variance and was significantly better than the other models (P < 0.001); however, none of the models had acceptable fit. Internal consistency (Cronbach α = 0.84) and test-retest reliability (ICC = 0.94) were satisfactory. The ODI was positively correlated with VAS (rs = 0.54, P < 0.001) and negatively correlated with all of the SF-36 sections (rs = - 0.35 to - 0.64, P < 0.001, all), apart from the role-physical (rs = - 0.02, P = 0.767). CONCLUSIONS: The Croatian version of the ODI has acceptable psychometric properties. It appears to be suitable for assessment of LBP and treatment outcomes in Croatian-speaking patients. Overall, there was no evidence to reject the original unidimensional structure in favor of a two-factor solution. As such, the unidimensional structure should continue to be used in future studies. These slides can be retrieved under Electronic Supplementary Material.

Scarcity of Implants Has Partially Replaced Cervical Spondylotic Myelopathy Decompression and Instrumented Fusion with Implant-Less Expansile Cervical Laminoplasty: Poverty Teaches all the Arts.

OBJECTIVE: The scarcity of implants during the economic crisis partially has replaced decompression and instrumented fusion for the treatment of cervical spondylotic myelopathy with implant-less expansile cervical laminoplasty (ECL). The aim of the study was to compare the results obtained with instrumented anterior cervical corpectomy and fusion with implant-less ECL. METHODS: Patients suffering from cervical spondylotic myelopathy Nurick 3-5 with preoperative tethering and postoperative untethering were included. Exclusion criterion was kyphosis more than 10°. Patients were assessed according to 30-meter walking track (30mWT), Nurick, and modified Japanese Orthopaedic Association scale scores. Kinematic magnetic resonance imaging 3-dimensional subaxial spinal cord reconstructions were 3 dimensionally modeled to confirm preoperative pincer clamping and follow-up unclamping to measure subaxial spinal cord length and pia envelope area (PEA). RESULTS: A total of 35 patients divided in the ECL (n = 19) and the anterior cervical corpectomy and fusion (n = 16) groups were selected from 534 patients operated on between September 1, 2008, and August 31, 2013 as the result of degenerative cervical disorders. Patients improved according to Nurick and modified Japanese Orthopaedic Association scores without differences between groups. Follow-up 30mWT analysis showed greater decrease in steps number and time in ECL group, creating the basis for further imaging analysis. Magnetic resonance imaging analysis showed that spinal cord length (mm) shortened more (4.47 ± 1.87 vs. 1.5 ± 2.5, t = -4.02; P = 0.0003) and PEA (mm2) shrank more (95.58 ± 43.73 vs. 22.94 ± 33.11, t = -5.45, P < 0.0001) in the ECL group. Multivariate logistic analysis showed that Δ 30mWT-time and Δ PEA were a very predictive model when area under the receiver operating characteristic curve is 0.98. CONCLUSIONS: Our results created a nidus for further research of postdecompression spinal cord relaxation.

Long-Term Results and Efficacy of Laminectomy with Fusion Versus Young Laminoplasty for the Treatment of Degenerative Spinal Stenosis.

OBJECTIVE: In the treatment of degenerative lumbar stenosis, facet-sparing laminectomy with instrumented fusion (FSL) was recently almost totally replaced by less invasive, allegedly equally effective surgical techniques. We performed a long-term comparison between outcomes after Young laminoplasty (YL) as a representative of the less invasive technique and FSL. METHODS: From December 4, 2000, to March 11, 2005, 56 patients with a history of neurogenic claudication and radiologically verified absolute lumbar stenosis were surgically treated. After applying inclusion and exclusion criteria, 44 patients were enrolled. RESULTS: Using the Oswestry Disability Index scale, significant improvement on 1-year and 8-year follow-up examinations was noticed in the FSL and YL groups. The Oswestry Disability Index was significantly better in the FSL group compared with the YL group at the 8-year follow-up (27.82 ± 1.918 vs. 40.74 ± 2.163). CONCLUSIONS: FSL is a more invasive and more expensive surgical technique than YL. In a short-term and long-term follow-up comparison, FSL is a more successful operative technique, and the difference increases over time in favor of FSL.

Provocative discography screening improves surgical outcome.

OBJECTIVE: The objective of this study was to compare the surgical outcomes of patients operated on, with or without discography prior to operation. METHODS: The study was designed as a randomized controlled trial, using power analysis with McNemar's test on two correlated proportions. The study comprised of 310 patients divided into trial (207) and control (103) groups. Inclusion criteria were low back pain resistant to nonsurgical treatment for more than 6 months and conventional radiological findings showing degenerative changes without a clear generator of pain. Exclusion criteria were red flags (tumor, trauma, and infection). After standard radiological diagnostic imaging (X-ray, CT, and MR), patients filled in the Oswestry Disability Index (ODI), SF-36, Zung, and MSP questionnaires. Depending on their radiological findings, patients were included and randomly placed in the trial or control group. At the 1-year follow-up examination, patients filled in the ODI, SF-36, and Likert scale questionnaires. RESULTS: The difference between preoperative and postoperative ODI in the control group degenerative disc disease (DDD) subgroup was 22.07 %. The difference between preoperative and postoperative ODI in the trial group DDD subgroup was 35.04 %. Differences between preoperative and postoperative ODI in the control group other indications subgroup was 26.13 %. Differences between preoperative and postoperative ODI in the trial group other indications subgroup was 28.42 %. CONCLUSIONS: DDD treated surgically without discography did not reach the clinically significant improvement of 15 ODI points for the patients treated with fusion. Provocative discography screening with psychological testing in the trial group made improvement following fusion clinically significant.

Brachial plexus injuries complicating video-assisted thoracic surgery.

OBJECTIVE: Video-assisted thoracic surgery (VATS) is a less-invasive alternative to open thoracotomy. According to evidence-based medicine methodology, VATS is associated with better outcomes and the same complication rate as open thoracotomy. CASE DESCRIPTION: Two women (19 and 21 years old) underwent VATS for treatment of pneumothorax. In an attempt to perform hemostasis, the subclavian arteries had to be occluded. Total sensorimotor deficit in both patients on the side where surgery was performed was noticed postoperatively. After 3½ months in patient 1, nerve roots C5 and C6 were neurolyzed. Neuromas of middle and lower trunks and posterior and medial cords were resected and graft repair with sural nerves was performed. In the second patient, 1 month after VATS the entire plexus was neurolyzed because of severe fibrosis. Following neurolysis, positive nerve action potentials (NAPs) were recorded. Patient 1 after the 6-year follow-up has full range of motion of the shoulder and elbow. Extension and flexion in the wrist and fingers recovered to M4/5. Pain sensation and two-point discrimination recovered. Patient 2 after 2½-year follow-up recovered full range of motion of the shoulder, elbow, and forearm. Pain sensation recovered in dermatomes C5 and C6. CONCLUSIONS: The two presented cases show that VATS is not without severe complications, as evidence-based medicine methodology suggests. Surgical findings in our patients imply that if this type of complication happens, early surgical exploration could be the best option for the patients.

[Guidelines for prevention, control and treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA): changes and updates of chapter 7.0: treatment of patients with MRSA infection]. / Smjernice za prevenciju, kontrolu i lijecenje infekcija koje uzrokuje meticilin-rezistentni Staphylococcus aureus (MRSA): izmjena i dopuna poglavlja 7.0.: lijecenje bolesnika s MRSA - infekcijom.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen throughout the world, and as well in Croatia. Therefore it was decided to develop guidelines with the aim to reduce the number of patients infected/colonized with MRSA in healthcare facilities and in nursing homes in Croatia, consequently reducing MRSA-related morbidity and mortality. An interdisciplinary team of experts developed these guidelines using existing international guidelines from different countries, and literature reviews about prevention, control, treatment and laboratory diagnosis of MRSA infections. Grades of evidence for specific recommendations were determined using CDC/HICPAC grading system. Categorization is based on existing data, theoretical basis, applicability and economic impact. After a broad discussion in different professional societies, Guidelines were accepted. In the meantime, several new possibilities appeared in the treatment of patients with MRSA infections in Croatia, so the Chapter 7.0 Treatment of patients with MRSA infections is changed and updated according to the new treatment possibilities. The rest of the Guidelines was not changed.

Anterior neurodecompression of kyphotic spondylogenic myelopathy Ranawat grade III and posterior decompression of lordotic spine improve walking ability.

Cervical spondylosis is common condition rarely associated with radiculomyelopathy which surgical treatment, according to meta-analysis, is not better than nonsurgical. Our hypothesis was that neurodecompression which type is chosen according to spinal alignment should result in better functional improvement comparing with nonsurgical treatment. Between January 1, 1998 and December 31, 2007 a total of 77 patients with spondylogenic myelopathy were selected for the study. The inclusion criteria were symptoms and signs of myelopathy Ranawat grade III. Exclusion criteria were amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). The curvature of the cervical spine was determined by Ishihara index. Anterior corpectomies and fusion was performed in the kyphotic spines, laminectomy with fusion in patients with neutral position, and open door laminoplasty in lordotic spines. Clinical improvement was assessed as differences between preoperative and 1-year follow up Nurick, modified Japanese Orthopedic Association (mJOA) myelopathy scales and walking test. Preoperative and postoperative transverse cord area and subarachnoid space were measured. Forty-four male and 31 female patients were surgically treated. Two patients with electrophysiological signs of ALS were excluded. Preoperative and postoperative mean +/- SD mJOA index was 9.15 +/- 1 and 13.01 +/- 1.4 (p < 0.001), Nurick grading scale 3.05 +/- 0.7 and 1.8 +/- 0.6 (p < 0.001), walking time (sec) 64.4 +/- 3.2 and 46.2 +/- 3.3 (p < 0.001), and number of steps 69.7 +/- 4.4 and 57.6 +/- 2.8 (p < 0.001) respectively. Preoperative and postoperative transverse cord area (mean +/- SD, mm2) was 46.7 +/- 5.4 and 60.2 +/- 2.6 (p < 0.001), and subarachnoid space 48.0 +/- 4.9 and 68.8 +/- 8.5 (p < 0.001) respectively. Our results showed that surgical treatment is beneficial for patients with spondylogenic myelopathy.

Analysis of muscle forces acting on fragments in pelvic fractures.

CT was used in 50 adult pelvic fractures to determine the size and the position of relevant muscles with regard to bony elements in order to calculate muscle forces acting upon certain pelvic portions. Muscle length was measured to calculate muscle volume and physiological muscle cross-section. Among others, the size and direction of muscle forces were calculated for iliac, pubic and ischiadic fractures. The strongest muscle acting in iliac fractures is m. gluteus medius. The strongest upward pulling of iliac bone fragments is exerted by the erector muscles, while the major anterior, medial and downward pulling is performed by the iliopsoas muscle. In pubic bone fractures, eight muscles push bone fragments downward, the strongest among them being m. adductor magnus. Two muscles pull them upwards: m. rectus abdominis and m. obliquus externus. Nine muscles are responsible for downward displacement of bone fragments in ischiadic fractures, but the strongest is m. semitendinosus. Calculation of moments of muscle forces acting upon bone fragments using CT of pelvic fractures gives additional data for planning of optimal operative treatment that can guarantee stable fixation in individual patients.

[Guidelines for prevention, control and treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA)]. / Smjernice za prevenciju, kontrolu i lijecenje infekcija koje uzrokuje meticilin-rezistentni Staphylococcus aureus (MRSA).

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen throughout the world, and in Croatia as well. Therefore it was decided to develop guidelines with the aim to reduce the number of patients infected/colonized with MRSA in healthcare facilities and in nursing homes in Croatia, consequently reducing MRSA-related morbidity and mortality. An interdisciplinary team of experts developed these guidelines using existing international guidelines from different countries, and literature reviews about prevention, control, treatment and laboratory diagnosis of MRSA infections. Grades of evidence for specific recommendations were determined using CDC/HICPAC grading system. Categorization is based on existing data, theoretical basis, applicability and economic impact. After a broad discussion in different professional societies, Guidelines were accepted. Guidelines include recommendations for measures in prevention of MRSA spread, role of hospital management, rational use of antibiotics, measures in a case of outbreak, treatment of infections and brief review of community-acquired MRSA. At the end, appendices concerning hospital audit, algorithms of laboratory diagnosis, patient information and form for national MRSA surveillance were added.

Axial vs. angular dynamization of anterior cervical fusion implants.

Aim of our study was to compare anterior cervical fusion with fusion augmented with dynamic implants and with the first generation-plate. Methods. Patients with radiculopathy and/or myelopathy were included in a prospective cohort study. Clinical outcome was assessed according to the Nurick, Odom, and SF 36 scales. Rotation and translation of screws, and quality of fusion (Tribus) were assessed at the 6-week and 4-year follow-up examinations. Neurodecompression was performed in 81 patients (one-level N = 45, two-level N = 26 and multi-level N = 10) in the period from January 2001 to September 2003. 50 male and 31 female patients were divided into three groups, depending upon type of fusion: 1. Augmented with dynamic implants (N = 33), 2. Augmented with H-plate (N = 33), and 3. Non-augmented (N = 15), one-level. There were no significant differences in clinical outcomes between the groups. Dynamization was detected in both augmented groups: axial in the dynamic implant group (mean translation +/- SD = 2.67 +/- 0.79 mm), and angular in the H-plate group (angle of rotation 7.2 degrees +/- 3.04 degrees). Six-week fusion was significantly better in the dynamic implants and non-augmented groups, as compared with the H-plate group. Two patients in the H-plate group developed pseudoarthrosis, 7 patients in the dynamic implant group had supradjacent segment heterotopic ossification and two of these additional ankylosis. Three patients in the non-augmented group had dislodgement of the bone graft with transient dysphagia in one of them. Our results suggest that selection of implants is not crucial for clinical outcome. Subsidence is allowed with both fixation systems. Fusion is faster and more effective in the axially dynamized group.

Influence of depression on patients satisfaction with the outcome of microsurgical "key-hole" vs classical discectomy: prospective matched-cohort study.

AIM: To assess the influence of depression on patients' satisfaction with lumbar discectomy performed by two different surgical techniques. METHODS: A prospective matched-cohort analysis of classical lumbar discectomy following static imaging (n = 45) and microlumbar "key-hole" discectomy after dynamic CT/myelography (n = 55) was performed. The outcome was independently assessed using Prolo economic/activity (E) and functional/pain (F) scale, and depressiveness according to Hamilton rating scale. Patients without improvement on the Prolo scale were classified as failed back surgery syndrome, and with a Hamilton score 17 as depressive. RESULTS: The groups were well matched by age, sex, clinical presentation and incidence of depression. In the "key-hole" group, both activity and pain outcome were better than in the classical technique group (median E score (range) = 4 (2-5) vs 3 (2-4), p = 0.002, median F score (range) = 4 (2-5) vs 4 (1-5), p = 0.008). Eighteen patients were classified as failed back syndrome, 6 in the "key-hole" group, and 12 in the classical group (z = 3.16, p = 0.075). The incidence of failed back syndrome among non-depressive patients was significantly lower in "key-hole" group (2/55 patients vs 8/45, z = 2.345, p = 0.009). Occurrence of unsatisfactory results among depressive patients was very similar in both groups (4/55 patients vs 4/45, z = 0.296, p = 0.384). CONCLUSION: Introduction of functional imaging and "key-hole" technique decreased incidence of failed back syndrome among non-depressive patients. Unsatisfactory outcome among depressive patients was unrelated to the imaging and surgical technique. Connection between depression and failed back syndrome, although detected, remains unclear and must be further investigated.

Carpal tunnel release by limited palmar incision vs traditional open technique: randomized controlled trial.

AIM: To compare a limited palmar incision for carpal tunnel release (CTR) with a traditional open technique, which is still considered the gold standard. METHODS: Seventy-two patients with a carpal tunnel syndrome were individually randomized into the trial (limited incision CTR) (n=36) and control group (traditional technique CTR) (n=36). In the trial group, skin incision parallel to the thenar crease was made up to 2.5 cm in length, under an operating microscope and endoscopic transillumination. Skin incision in the control group began at the distal border of the carpal ligament, followed the longitudinal crease of the palm, and crossed the base of the palm in a zigzag fashion. Three months after surgery, the patients were asked about symptomatic relief and intervals between the operation and return to their daily activities and work, and examined for scar tenderness and esthetic outcome. Distal motor latency, conduction velocity, scar length, scar width, and operation time were measured. RESULTS: There were no differences between the two groups in symptomatic relief and electrophysiological parameters. Intervals between the operation and return to daily activities (median 5 days, range 2-15) were shorter in the trial group than in the control group (median 10 days, range 2-21; p<0.001), as well as the intervals between the operation and return to work (median 15 days, range 5-45 vs median 30 days, range 10-60; p<0.001). Scar/pillar tenderness, scar length and width, esthetic outcome, and operation time were significantly better in the trial group. CONCLUSION: Limited palmar incision CTR is as effective and safe as traditional CTR technique, but with better postoperative recovery and cosmetic results.