Yusuf Sukru Caglar

Biomechanical comparison of inside-outside screws, cables, and regular screws, using a sawbone model

Our aim was to conduct a biomechanical comparison of the pull-out strengths of inside–outside (I/O) screws, cables, and bone screws to determine whether I/O screws provide greater pull-out resistance than cables or bone screws, and their effectiveness with the screw diameter. There is no remarkable biomechanical experimental study comparing the I/O technique with conventional spinal techniques. The diameter of the screw heads were also biomechanically tested to determine the optimal size that can be used. In this study, 45 blocks of 50×50×5 mm of “sawbone” (synthetic bone, model 1137, Pacific Research Laboratories, Vashon, WA, USA) were used as bone substitutes. Fifteen sets of 14-mm inside–outside Dynalok screws and nuts, 15 wire cables, and 15 bone screws were inserted into a separate sawbone block. An MTS Bionx materials testing machine was used to measure the load to failure of each implant. The mean values and standard deviations of each group were calculated and Student’s t-test was used for comparison. The load to failure of the inside–outside screws was significantly greater than that of the cables (p<0.0000004) and the regular bone screws (p<0.000002). The results also revealed that increasing the diameter of the head of the screw also increases the resistance against the pull-out strengths. Thus, using a larger screw in occipitocervical stabilization provides safe and stable fixation of the occipital bone to the cervical spine. This study also proved that sawbone is a useful and reliable alternative to allogenic fresh cadaveric bone grafts or animal bones for certain biomechanical testing.

Ruptured aneurysm of the posterior spinal artery of the conus medullaris.

A case of a posterior spinal artery aneurysm of the conus medullaris is presented. The patient presented with severe lower back pain with radiation into the right leg. Spinal angiography was consistent with a partially thrombosed arteriovenous malformation (AVM) or an aneurysm. At operation a partially thrombosed aneurysm of the posterior spinal artery was found at the level of conus medullaris, which, after review of the literature, is the first case treated with total microsurgical excision.

Chondroblastoma of the thoracic vertebra.

A 48-year-old patient with interscapular pain was admitted to our clinic. MRI revealed a mass infiltrating the second thoracic vertebra and adjacent structures. No other clinical manifestations were observed in general examination. The patient underwent surgery and subtotal removal was achieved while anterior and posterior stabilisations were performed. Diagnosis was pathologically confirmed. As thoracic chondroblastoma cases are not frequent, we decided to present this case.

The histopathological and ultrastructural effects of the topical application of bacitracin on the cerebral cortex in rats.

AIM Bacitracin is one of the most frequently used agents for the topical irrigation of the cerebral cortex. The aim of this study is to investigate whether bacitracin has histopathological and ultrastructural effects when applied topically to the cerebral cortex. MATERIAL AND METHODS Twenty-eight rats were randomly assigned to four groups. Except the control group, each rat underwent left frontoparietal craniectomy with dural removal. Then, in the sham group a piece of dry absorbable gelatin sponge was placed over the left hemisphere; in the saline group a gelatin sponge soaked in normal saline; and in the bacitracin group a gelatin sponge soaked in 500 units bacitracin was used. After 48 hours, brain tissues were extracted for histopathological and electron microscopic analyses. RESULTS Among the four groups dark stained neurons were found to be statistically higher in number in the bacitracin group compared with the control, sham and saline groups. Electron microscopic evaluation revealed that, in the bacitracin group, almost all cytoplasmic organelles were poorly preserved. CONCLUSION Topical application of the bacitracin on to the cerebral cortex caused histopathological and ultrastructural changes in the neural tissue. These changes may be an evidence for the neurotoxic effects of bacitracin.

Importance of the perforating arteries in the proximal part of the PICA for surgical approaches to the brain stem and fourth ventricle - an anatomical study

OBJECTIVE The purpose of this study is to examine the perforating arteries (PAs) in the proximal part of the posterior inferior cerebellar artery (PICA) for surgical approaches to the brain stem and fourth ventricle, and to stress their importance in microsurgical procedures. METHODS Twenty-six adult cadaver obtained from routine autopsies were used. During the examination, the PAs and the segmental structure of the proximal part of the PICAs and their relation to the neighbouring anatomical structures were demonstrated. RESULTS We classified the PICAs into 4 types on the basis of the distance of the middle point of the width of the caudal loop to the midline, and their presence or absence as Group A (symmetrical, anterior medullary type: 26.9%), Group B (lateral medullary type: 15.4%), Group C (asymmetrical type: 38.5%), and Group D (unilateral type: 19.2%). The number of the PAs in the tonsillomedullary segment and the caudal loop was higher than those originating from the other segments. CONCLUSIONS Approaches to the medial or lateral of the PICA should be made in a way that protects the PAs (avoiding retraction of the PICA). Otherwise the PAs will be damaged and as a result brain stem ischaemia may occur, which can have serious clinical outcomes.

Is a Unilateral Surgical Approach Effective in Patients with Bilateral Leg Pain with Unilateral Lumbar Disc Herniation? A Prospective Nonrandomized Clinical and Surgical Study

OBJECTIVE To examine the surgical results of unilateral lumbar discectomy in patients with bilateral leg pain and discuss short- and long-term outcomes within the limits of lumbar decompression. METHODS We analyzed 60 patients with unilateral disc herniation who underwent unilateral lumbar discectomy and hemipartial laminectomy between 2014 and 2017. Group 1 (30 patients) had bilateral leg pain and unilateral lumbar disc herniation. Pain lateralization was determined radiologically. Group 2 (30 patients) had unilateral leg pain and unilateral lumbar disc herniation. Pain scores were preoperatively evaluated with visual analog scale (VAS) for both legs and Oswestry Disability Index (ODI) for overall life quality. In both groups, surgery was performed on the ipsilateral side of the herniated disc. Scores were repeated on postoperative day 1 and 1, 3, 6, 12, and 24 months later. VAS score differences for pain lateralization and disc levels were compared in group 1. ODI score differences were compared between both groups. Results were statistically analyzed. RESULTS VAS score differences were statistically significant at all follow-up time points in patients with ipsilateral and contralateral pain. VAS score differences between L4-L5 and L5-S1 level discopathies were statistically insignificant for all time points in both groups. All postoperative ODI score decreases for all time points were statistically significant (P < 0.001) for both groups, whereas the differences between groups 1 and 2 were statistically insignificant. CONCLUSIONS Conventional lumbar disc surgery alone is sufficient for the ipsilateral side of radiologically demonstrated disc herniation in patients with bilateral leg pain.

Effect of Riluzole on Spinal Cord Regeneration with Hemisection Method Before Injury

OBJECTIVE The pathophysiology of spinal cord injury (SCI) with the information obtained to date has not been elucidated fully. A safe drug or treatment protocol that results in cell regeneration for SCI remains unknown. Neuroprotective and neuroregenerative effects of riluzole, administered after a SCI, have been shown in experimental studies. This study aimed to investigate the effect of riluzole on neural regeneration in a rat SCI model. METHODS Thirty-two rats were divided into 8 groups, with 4 rats in each group. Hemisection method was performed after T7-T9 laminectomy. Rats were intraperitoneally aministered with riluzole (6 mg/kg). Locomotor recovery of the rats was assessed at 1 day, and 1, 2, 3, and 4 weeks after the 21-point Basso, Beattie, and Bresnahan test. Subsequently, the spinal cords of the rats were scored according to a semiquantitative grading system using a light microscope, and the numbers of myelinated axons, neurons, and glial cells were calculated. RESULTS Basso, Beattie, and Bresnahan test changes were statistically significant when groups 4-6 and 8 were compared with the other groups (P < 0.05, P < 0.00625). The results of the numbers of neurons, glial cells, and myelinated axons were statistically significant. Especially group 8, in which riluzole was administered 5 days before injury, more positive clinical and histopathologic results were obtained. CONCLUSIONS Riluzole treatment is more effective when provided before injury. Riluzole may contribute to functional recovery when used in the preoperative period in patients who are at a high risk for permanent neurologic deficit.

Endoscopic endonasal approaches to craniovertebral junction pathologies: a single-center experience

AIM: To review our experience of using the endoscopic endonasal approach for clivus and odontoid pathologies as well as craniovertebral junction anomalies at our institution. MATERIAL and METHODS: We retrospectively evaluated 41 patients (21 male, 20 female; age range, 2–65 years) who underwent endoscopic endonasal procedures for craniovertebral junction pathologies between 2008 and 2017. RESULTS: Of the 41 patients, 27 had clivus lesions, 7 had odontoid lesions, 6 had basilar invagination, and 1 had rhinorrhea repair. Six patients underwent an additional posterior decompression/fusion either before or after the endonasal procedure. None of the patients required tracheostomy, and cerebrospinal fluid leakage was postoperatively detected in one patient. The patients’ mean modified Rankin scale and visual analog scale scores were 3 and 4, respectively. The follow-up period ranged from 12 to 50 months. CONCLUSION: Although the microscopic transoral approach has been considered the gold standard for craniovertebral junction surgical management, endoscopic approaches are feasible, safe, and effective for addressing pathologies in this region, with developing technique and surgical experience.

Osteogenesis Imperfecta and Extra-/Intradural Hematomas: A Case Report and Review of the Literature

Osteogenesis imperfecta, also named as brittle bone disease, is characterized by fragile bones and short stature caused by mutations in the collagen gene. Subdural and intraparenchymal hematomas are defined and associated with trauma, vascular causes, and systemic bleeding diathesis. Skull fragility may lead to epidural hematoma, which is a life-threatening situation. Vascular fragility and intrinsic platelet defects are the causes of bleeding in patients with osteogenesis imperfecta, which is a major management challenge for neurosurgeons. Here, we reported on a 5-year-old boy with osteogenesis imperfecta with epidural hematoma and skull fracture following a trivial trauma, and made a literature review of 28 cases with extra-/intradural hematoma.