Effect of clival bone growth on the localization of the abducens nerve at the petroclival region: a postmortem anatomical study.

PURPOSE: To investigate the effect of the clival bone pattern on the abducens nerve (AN) localization in the petroclival region between the Pediatric and Adult Groups. METHODS: This study used 12 pediatric and 17 adult heads obtained from the autopsy. The length and width of the clivus and the length of the petrosphenoidal ligaments (PSLs) were measured. The ratio of the length and width of the clivus was accepted as the clival index (CI). The localization of the AN at the petroclival region below the PSL, classified as lateral and medial, were recorded. RESULTS: The average length of the clivus was 26.92 ± 2.88 mm in the Pediatric Group, and 40.66 ± 4.17 mm in the Adult Group (p < 0.001). The average width of the clivus was 22.35 ± 2.88 mm in the Pediatric Group, and 29.96 ± 3.86 mm in the Adult Group (p < 0.001). The average value of the CI was 1.20 in the Pediatric Group and 1.36 in the Adult Group (p = 0.003). The length of the PSL was 7.0 ± 1.47 mm in the Pediatric Group and 11.05 ± 2.95 mm in the Adult Group (p < 0.001). The nerve was located below the medial side of the PSL in the Pediatric Group and below the lateral side in the Adult Group (p = 0.002). CONCLUSIONS: The petrous apex localization of the AN in adults compared with pediatric subjects could be related to the increased growth in the length of the clivus than its width.

Relationship between subarachnoid and central canal hemorrhage and spasticity: A first experimental study.

Objective: Spastic disorders are considered as important cerebral complications of subarachnoid hemorrhage (SAH). However, there has been no research concerning the pathophysiological mechanism of its link with the spinal cord. The present study aimed to assess the relationship between the development of spasticity and neuronal degeneration after SAH and increase in spinal cord pressure after central canal hemorrhage (CCH).Participants: Twenty-three rabbits were included.Outcome measures: Of all rabbits, 5, 5, and 13 were allocated in the control, SHAM and study groups, respectively. Moreover, 1 cc of saline and 1 cc of autologous arterial blood were injected into the cisterna magna of the SHAM and study groups, respectively. The Muscle spasticity tension values (MSTVs) were determined according to the modified Ashworth scale. Degenerated neuron densities (DND) in the gray matter (GM) of each animal's spinal cord were stereologically calculated.Results: The average MSTV of each group was as follows: control group (n = 5) 2; SHAM group (n = 5) 3-5; and study group (n = 13) 8-10. The DND values of the spinal cord of each group were as follows: control group, 2 ± 1/mm3; SHAM group, 12 ± 3/mm3; and study group, 34 ± 9/mm3. Results showed an important linear relationship between the MSTVs and the DND of the spinal cord (P < 0.001).Conclusion: Spasticity may be attributed to other causes such as ischemic neurodegenerative process that develops after spinal SAH and the de-synchronization of the flexor-extensor muscles due to the spontaneous discharge of interneuronal structures, which are crossed within the spinal cord owing to the build-up of pressure after CCH.

Comparison of Thalamus Volume on Magnetic Resonance and Cadaveric Section Images.

AIM: To measure and to compare the volume of thalamus using magnetic resonance imaging (MRI) and the anatomical sections. MATERIAL AND METHODS: In this study, 13 brain specimens were used. First, the images were taken in 3 mm sections on MRI, the thickness of the thalamus was measured. Subsequently, 4 mm coronal sections were prepared using a microtome. The thalamic volumes calculated from cadaveric specimens were compared with the measurements obtained using MRI. RESULTS: On MRI, the mean thalamic volumes on the right and left hemispheres were found to be 5843.4 ± 361.6 mm3 and 5377.0 ± 666.2 mm3 respectively. The mean volumes of the cadaveric sections were 5610.8 ± 401.3 mm3 on the right side and 5618.5 ± 604.1 mm3 on the left hemisphere. No statistically significant difference was found between the volume calculated from MRI and that obtained from the cadaveric section (p < 0.05). CONCLUSION: This study shows a correlation between measurement of thalamus volume based on MRI and those calculated from anatomical sections. Our findings support the reliability of DBS procedures using MRI and stereotactic method.

Artifacts in cranial MRI caused by extracranial foreign bodies and analysis of these foreign bodies.

PURPOSE: The purpose of our study was to conduct a chemical analysis of extracranial foreign bodies (FBs) causing artifacts in cranial magnetic resonance imaging (MRI) and to investigate the association between chemical composition, magnetic susceptibility, and artifact size. MATERIALS AND METHODS: A total of 12 patients were included in the study. The FBs responsible for the artifacts were visualized using cranial computed tomography (CT). Artifact-causing FBs were removed from the scalps of 10 patients and analyzed using scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), X-ray diffraction spectroscopy (X-RD), and Fourier-transform infrared spectroscopy (FT-IR). The magnetic susceptibility of the samples was determined using the reference standard material MnCl2.6H2O. The volume of the MRI artifacts was measured in cubic centimeters (cm3). RESULTS: EDS results demonstrated that the mean Fe ratio was 5.82% in the stone samples and 0.08% in the glass samples. Although no phase peaks were detected in the X-RD spectra of the glass samples, peaks of Fe2O3, Al2Ca (SiO4) were detected in the X-RD spectra of the stone samples. The FT-IR spectra revealed metal oxide peaks corresponding to Fe, Al, in the stone samples and peaks confirming Al2SiO5 and Na2SiO3 structures in the glass samples. The mean volumes of the MRI artifacts produced by the stone and glass samples were 5.9 cm3 and 2.5 cm3, respectively. CONCLUSIONS: Artifacts caused by extracranial FBs containing metal/metal oxide components are directly associated with their chemical composition and the artifact size are also related to element composition and magnetic susceptibility.

Effect of Vasa Vasorum on Basilar Artery Vasospasm Following Subarachnoid Hemorrhage.

BACKGROUND: A well-documented association exists between the vasa vasorum and vasopathologies, including atherosclerosis. However, information on the role of the vasa vasorum during vascular degenerative changes of vasospasm after subarachnoid hemorrhage (SAH) is insufficient. METHODS: In this study, 34 rabbits were divided into 3 groups: basal group (N = 8), sham group (N = 8), and SAH group (N = 18). Experimental SAH was formed using a double-injection model. During follow-up, the neurologic status of the rabbits was observed. All rabbits were euthanized after 2 weeks, and the vasopathologic degeneration was categorized as normal, mild, moderate, and severe according to the changes in the basilar arteries. The numbers, locations, and spasms of the vasa vasorum and their relation to the vasodegenerative changes of the basilar artery were investigated. RESULTS: The basilar arteries were graded as normal in the basal and sham groups. In the SAH group, 6 rabbits had mild, 7 had moderate, and 5 had severe degeneration. Neurologic deficits were prominent in the SAH group, and deficit grades correlated with vascular degeneration. The number of the vasa vasorum were significantly higher in the SAH group, and an enhanced formation of the vasa vasorum was noted in which severe degenerative changes were present. Moreover, the vasospasm index of the vasa vasorum, which increased with the aggravation of vascular degenerative changes, was significantly higher in the SAH group. CONCLUSIONS: The vasa vasorum and their vasospasm play a crucial role in the pathogenesis of basilar artery degeneration in the vasospasm following SAH.

Aortic Injury by Thoracic Pedicle Screw. When Is Aortic Repair Required? Literature Review and Three New Cases.

PURPOSE: Aortic injury by pedicle screw is rare but can cause serious complications. It has not been clearly determined when aortic repair is necessary in cases of screw impingement without perforation of the aortic wall. In this article, we review the treatment and clinical course of pedicle screw aortic impingement and attempt to clarify this issue. METHODS: Cases of aortic injury during thoracic screw procedures were found using a MEDLINE search and analyzed together with 3 new cases that we present. RESULTS: Nineteen cases collected from the literature and 3 new cases were included in the study. In 7 of the cases, aortic impingement by the pedicle screw was detected during postoperative follow-up (day 1) radiologic examinations. In the other cases, time to presentation of aortic impingement ranged between 2 weeks and 60 months after fixation. The main indications for thoracic spinal fixation were post-traumatic vertebral fracture and kyphoscoliosis/scoliosis. Repair of the aortic damage ranged from primary repair to stent and tube graft placement by the thoracic endovascular aortic repair method. CONCLUSIONS: In cases in which the screw impinges less than 5 mm into the aortic wall, hardware revision without aortic repair may be sufficient if recognized early and there are no sign of aortic leakage in vascular imaging. However, cases with more than 5 mm of screw impingement should undergo aortic repair first, even in the absence of aortic leakage, following by screw revision.

Brachial Artery Vasospasm Caused by Cervical Dorsal Root Ganglion Degeneration After Subarachnoid Hemorrhage: An Experimental Study.

PURPOSE: Subarachnoid hemorrhage (SAH) may lead to vasospasm in various vessels. The cervical nerves have a vasodilatory effect on the upper extremity arteries. The aim of this study was to investigate if there is a relationship between C6 dorsal root ganglion (DRG) degeneration and brachial artery (BA) vasospasm after spinal SAH. METHODS: This experimental study was conducted on 23 rabbits. The animals were divided into 3 groups: control (n = 5), SHAM (n = 5), and study group (n = 13). One cubic centimeter (cc) of serum saline was injected into the cisterna magna of animals of the SHAM group; the same procedure was performed by 1 cc of homologous blood in the study group. Degenerated neuron densities (DNDs) of DRGs (n/mm3) at C6 levels and BA vasospasm indexes (VSI; wall surface/lumen surface) of all animals were determined and results were analyzed statistically. RESULTS: Mean VSI values of BAs and DNDs of C6DRGs of the control, SHAM, and study groups were estimated as 10 ± 3/1.12 ± 0.11 n/mm3, 34 ± 9/1.27 ± 0.24 n/mm3, and 1031 ± 145/2.93 ± 0.78 n/mm3, respectively. Mean DNDs and VSI values were statistically significantly different between the control and study groups (P < 0.0001). CONCLUSIONS: C6DRG degeneration may be considered as an important factor in the etiopathogenesis of severe BA vasospasm after SAH.

A New Neuropathologic Mechanism of Blood pH Irregularities After Neck Trauma: Importance of Carotid Body-Glossopharyngeal Nerve Network Degeneration.

OBJECTIVE: We created a neck trauma model by injecting blood into the sheath of rabbits' carotid bodies (CBs). Then we determined the relationship between neuronal degeneration of the CB due to hemorrhage of this organ and its clinical effects such as blood pH and heart rhythm. METHODS: The present study included 24 adult male New Zealand rabbits. The animals were divided into 3 groups: control (n = 5); sham (0.5 mL saline injected into CBs; n = 5); and study (CB trauma model; n = 14). pH values and heart rhythms were recorded before the experiment to determine the values under normal conditions, and measurements were repeated thrice in the days following the experiment. The number of normal and degenerated neuron density of CBs was counted. The relationship between the blood pH values, heart rhythms, and degenerated neuron densities was analyzed. RESULTS: Heart rhythms were 218 ± 20 in the control group, 197 ± 16 in the sham group (P = 0.09), and 167 ± 13 in the study group (P < 0.0005). pH values were 7.40 ± 0.041 in the control group, 7.321 ± 0.062 in the sham group (P = 0.203), and 7.23 ± 0.02 in study group (P < 0.0005). Degenerated neuron densities were 12 ± 4/mm3 in the control group, 430 ± 74/mm3 in the sham group (P < 0.005), and 7434 ± 810/mm3 in the study group (P < 0.0001). CONCLUSIONS: A high degenerate neuron density in the CB can decrease blood pH and hearth rhythm after neck trauma, and there might be a close relationship between the number of degenerated neurons and clinical findings (such as heart rhythm and blood pH). This relationship suggests that injury to the glossopharyngeal nerve-CB network can cause acidosis by disturbing the breathing-circulating reflex and results in respiratory acidosis.

Long-Term Outcomes of a New Minimally Invasive Approach in Chiari Type 1 and 1.5 Malformations: Technical Note and Preliminary Results.

BACKGROUND: The treatment options for patients with Chiari malformation type 1 (CM1) and Chiari malformation type 1.5 (CM1.5) have not yet been standardized. In these malformations, the main factors include obstruction at the level of the foramen magnum and dural and ligamentous thickening. Here we present our outcomes of surgery and decompression using a minimally invasive surgery (MIS) technique. METHODS: Sixty-one patients admitted to our clinics between 2009 and 2016 due to CM1 or CM1.5 and who had undergone MIS were investigated retrospectively. All patients were followed up for a mean period of 55 months, both clinically and radiologically, and the outcomes were recorded. RESULTS: All 61 patients underwent foramen magnum decompression through a 1.5-cm mini-open incision, C1 laminectomy and C2 medial inner side tour, posterior atlanto-occipital membrane removal, external dural delamination, and widening of the internal dura with longitudinal incisions. Fifty-six patients (91.8%) were satisfied with the outcome, 4 patients (6.5%) remained the same, and 1 patient (1.6%) reported a poor outcome. Forty-five percent of the patients with syringomyelia demonstrated resolution within 2 years, and 92% demonstrated resolution in 5 years. Scoliosis was seen in 5 patients (8.1%). The rate of benefit from the surgical procedure was statistically significant (P = 0.0045), and no patient required additional surgery because of poor decompression. CONCLUSIONS: MIS is effective for uncomplicated cases of CM1 and CM1.5 due to its minimal connective and muscular tissue damage, short surgical duration, short recovery time, early mobilization, effective posterior foramen magnum widening, lack of liquor fistula development, and better clinical and radiologic improvement during long-term follow-up.

Unexpected Rupture of a Giant Lobulated Thrombotic Middle Cerebral Artery Aneurysm and Emergency Surgical Treatment With Thrombectomy: A Case Report and Review of the Literature.

INTRODUCTION: The treatment of giant intracranial aneurysms is one of the most challenging cerebrovascular problems of neurosurgery. We report the rupture of a giant, lobulated, and almost completely thrombosed middle cerebral artery (MCA) aneurysm that is the ninth such report in the literature. We also investigated additional solutions used in the treatment of this patient. CASE PRESENTATION: A 58-year-old man had been admitted with headache 8 years previously (in 2005), and a giant MCA aneurysm was detected. Two separate endovascular interventions were performed, and both failed. The patient began to live with the giant aneurysm. As there was a large thrombosis filling the aneurysm lumen during the previous endovascular procedures, the aneurysm was not expected to rupture. However, a rupture eventually occurred, in 2013. Even if an aneurysm is very large, lobulated, old, and almost completely thrombosed, it can suddenly bleed. During surgery on this patient, we observed severe cerebral vasospasm caused by a giant thrombosed aneurysmal rupture. Despite the complications, surgery is a life-saving treatment for this emergency when other strategies are not possible. Thrombectomy and clipping are approaches that require a great deal of courage for the neurosurgeon, in terms of entering the risky area within the aneurysm. CONCLUSIONS: We believe that it would be more appropriate to plan for combined treatment with surgical and endovascular approaches before the emergency condition could occur.

Split Rib Cranioplasty for Frontal Osteoma: A Case Report and Review of the Literature.

INTRODUCTION: Osteomas are benign bone tumors. They generally lead to a local thickness on the frontal bone in calvarium. When they occur on the forehead, they often cause a cosmetic disorder without any neurological symptoms. The significant problem is the repair method of the cranium defect. CASE PRESENTATION: The rib of a 34-year-old female was split and used for a small cranium defect of 3 × 3.5 cm. The preferred method and the obtained results were presented under the guidance of the literature. CONCLUSIONS: Along with the technological advancement, different materials are employed according to the size of the cranium defect and the age of the case. The application of split costa cranioplasty for the small cranium defects in the region of patient's face is the method with the least possibility of complications, and its cosmetic and functional results are quite promising.

Reduction and arthrodesis with sublaminar spiral silk in atlantoaxial joint instability.

OBJECTIVE: The aim of this study was to evaluate the clinical and radiologic results of the use of thick spiral silk knotting instead of sublaminar wiring for C1-C2 arthrodesis in patients with atlantoaxial instability. METHODS: We retrospectively evaluated 16 patients (10 females, 6 males; mean age: 43.4 years; mean follow-up: 34 months) with atlantoaxial instability who underwent C1-C2 fusion by reduction and sublaminar spiral silk knotting. All patients underwent open reduction, bounding both laminae with thick spiral silk instead of wiring and arthrodesis with autografting. Reduction rates, screw position and fusion rates were evaluated using computed tomography. RESULTS: Preoperative mean atlantodental interval (ADI) was 8 (range: 6 to 11) mm and postoperative ADI was 2.1 (range: 0.5 to 2.5) mm. There was no dural or spinal cord injury. Complete reduction was observed in all cases. Fusion was unsuccessful in 1 case (6.25%). Postoperative mean flexion ADI was 10 mm and mean extension ADI was 1 mm. Graft separation between C1-C2 was observed in slice tomographic examination in one patient. Malposition was observed in 2 screws (4%). CONCLUSION: The sublaminar silk knotting technique appears to provide safe anatomical reduction. As this method is cheap and simple and does not require extra implantation, loosen, create neurologic compromise or cause radiologic crowding, it can be considered an alternative surgical technique to sublaminar wiring.

Long term results of lumbar sequestrectomy versus aggressive microdiscectomy.

It remains unknown whether aggressive microdiscectomy (AD) provides a better outcome than simple sequestrectomy (S) with little disc disruption for the treatment of lumbar disc herniation with radiculopathy. We compared the long term results for patients with lumbar disc herniation who underwent either AD or S. The patients were split into two groups: 85 patients who underwent AD in Group A and 40 patients who underwent S in Group B. The patients were chosen from a cohort operated on by the same surgeon using either of the two techniques between 2003 and 2008. The demographic characteristics were similar. The difference in complication rates between the two groups was not statistically significant. During the first 10 days post-operatively, the Visual Analog Scale score for back pain was 4.1 in Group A and 2.1 in Group B, and the difference was statistically significant (p<0.005). The Oswestry Disability Index score was 11% in Group A and 19% in Group B at the last examination. The reherniation rate was 1.5% in Group A and 4.1% in Group B (p<0.005). We argue that reherniation rates are much lower over the long term when AD is used with microdiscectomy. AD increases back pain for a short time but does not change the long term quality of life. To our knowledge this is the first study with a very long term follow-up showing that reherniation is three times less likely after AD than S.

The role of sympathectomy on the regulation of basilar artery volume changes in stenoocclusive carotid artery modeling after bilateral common carotid artery ligation: an animal model.

BACKGROUND: Stenoocclusive carotid artery disease causes important histomorphologic changes in all craniocervical vasculatures, such as luminal enlargement, vascular wall thinning, elongation, convolutions, and aneurysm formation in the posterior circulation. Although increased pressure, retrograde blood flow, and biochemical factors are described in the pathogenesis of vascular remodelisation, the vasoregulatory role of the autonomic nervous system has not been investigated thus far. We investigated the relationship between the sympathetic nervous system and the severity of histomorphologic alterations of basilar arteries after bilateral common carotid artery ligation (BCCAL). MATERIAL AND METHODS: This study was conducted on 21 rabbits. The rabbits were randomly divided into three groups: baseline group (n = 5), sympathectomy non-applied group (SHAM; n = 8), and sympathectomy applied group (n = 8) before bilateral common carotid artery ligation. Permanent ligation of the prebifurcations of the common carotid arteries was performed to replicate stenoocclusive caroid artery disease. Basilar artery volumes were measured after ligation. Volumes of the basilar arteries were estimated by stereologic methods and compared between groups. RESULTS: Luminal enlargement, wall thinning, elongation, convolutions, and doligoectatic configurations were detected in the majority of basilar arteries. The mean basilar arterial volume was 4.27 ± 0.22 mm3 in the baseline group; 5.28 ± 0.67 mm(3) in the SHAM group, and 8.84 ± 0.78 mm3 in the study group. The severity of basilar enlargement was significantly higher in the study group compared with the SHAM (p < 0.005) and baseline groups (p < 0.001). CONCLUSIONS: Sympathectomy causes basilar artery enlargment, which is beneficial for maintaining cerebral blood flow; however, it also causes wall thinning, elongation, convolution, and aneurysm formation, which may be hazardous in stenoocclusive carotid artery disease. Sympathectomy can prevent new vessel formation and hyperthyrophic changes at the posterior circulation. Neovascularisation is not detected adequately in sympathectomised animals.

Effect of inner membrane tearing in the treatment of adult chronic subdural hematoma: a comparative study.

The postoperative results of chronic subdural hematoma (CSDH) procedures using catheterization and tearing of inner membrane (CTIM) technique have not previously been discussed in the literature. This article compares the effects of CTIM technique on brain re-expansion and re-accumulation with cases operated on with a burr-hole craniotomy and outer membrane incision (BCOMI) technique. The study involved operations on 144 patients (Group 1) using the CTIM technique and 108 patients (Group 2) using the BCOMI technique. In the operations using the CTIM technique in Group 1, the mean effusion measured in the subdural space (SDS) was 10.0 ± 0.2 mm, and for Group 2, 14.3 ± 0.6 mm in the postoperative period on the first and third days and this difference was found to be significant (p < 0.05). The means were 6.6 ± 0.2 mm for Group 1 and 10.3 ± 0.5 mm for Group 2 on the seventh day (p < 0.05). Recurrence rate was 8.3% in Group 2 and 0 in Group 1. This difference was statistically significant (p = 0001). The length of hospital stay was 7.0 ± 0.1 days for the Group 1 and 8.8 ± 0.2 days for Group 2 and this difference was significant (p < 0.05). These results indicate that the CTIM technique is preferable because it results in earlier re-expansion, lower recurrence, less subdural effusion and pneumocephalus, and shorter hospital stays.

New practical landmarks to determine sigmoid sinus free zones for suboccipital approaches: an anatomical study.

Literature defines the landmarks to identify the courses and locations of the transverse and sigmoid sinuses on the outer surface of the skull and inner surface of the scalp. These natural landmarks may only be helpful after skin incision and are inadequate to determine the length and size of the skin incision. Still, there is a need to identify palpable landmarks easily to determine the ideal location to open the initial burr hole before an operation. Twenty-eight dried adult human skulls and 2 cadavers were evaluated. The zygomatic root, the inion, and the mastoid process were identified on the external, and the grooves for sigmoid and transverse sinuses, on the internal surfaces. The distances between the 3 landmarks and the midpoints, and the shortest distances of the midpoints to the border of the groove for sigmoid sinus and groove for transverse sinus were measured. Statistically significant differences were evaluated for both sides. Based on the measurements, the defined "artificial landmarks" can be considered safe points that involve no vascular structures and may be used to perform the initial burr hole during posterolateral approaches. Identification of the midpoints and palpation of the defined landmarks easily before the operation render the study feasible and practical unlike with natural landmarks. To avoid venous injury, the midpoints of mastoid-inion line and zygomatic root-inion line can be used safely in skin incision during posterior fossa approaches and craniotomy.

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.