Intimal Hemorrhage of Basilar Artery Induced by Severe Vasospasm Following Subarachnoid Hemorrhage: The Experimental Analysis.

BACKGROUND: Cerebral vasospasm, a serious complication of subarachnoid hemorrhage (SAH), has been extensively studied for its neurochemical and pathophysiologic mechanisms. However, the contribution of inner elastic membrane dissection and subintimal hemorrhage to basilar artery occlusion remains underexplored. This study investigates inner elastic membrane-related changes in the basilar artery after SAH. METHODS: Twenty-four hybrid rabbits were divided into control, sham, and SAH groups, with SAH induced by autologous blood injection. After 2 weeks, basilar artery changes, vasospasm indexes (VSIs), and dissections were evaluated. RESULTS: The SAH group showed significantly higher VSI, with vascular wall thickening, luminal narrowing, convoluted smooth muscle cells, intimal elastic membrane disruption, endothelial cell desquamation, and apoptosis. Some SAH animals exhibited subintimal hemorrhage, inner elastic membrane dissection, and ruptures. Basilar arteries with subintimal hemorrhage had notably higher VSI. CONCLUSIONS: These findings highlight the role of subintimal hemorrhage and inner elastic membrane dissection in basilar artery occlusion post-SAH, offering valuable insights into vasospasm pathophysiology.

Overlooked evidence for transmission deficit of pupillary light reflex can be secondary to trigeminal nerve ganglion degeneration following subarachnoid hemorrhage; preliminary experimental study.

OBJECTIVE: Although the effect of oculomotor and cervical sympathetic networks on pupil diameter is well known; the effect of the trigeminal nerve on pupil diameter has not been investigated yet. This subject was investigated. MATERIALS AND METHODS: Five of 23 rabbits were used as a control group (GI; n = 5); 0.5 ccs saline solution into cisterna magna injected animals used as SHAM (GII; n = 5); autologous blood injected to produce SAH used as the study group (GIII; n = 13) and followed up three weeks. Light-stimulated pupil diameters were measured with an ocular tomography device before, middle, and at the end of the experiment. Considering the sclera area/pupil area ratio index (PRI) as the pupillary reaction area, we used this equation for the pupil's rush to light. Degenerated neuron densities of trigeminal ganglia and pupil diameters compared with the Mann-Whitney U test. RESULTS: The PRI, degenerated neuron density of trigeminal ganglia (n/mm3) were: (2.034 ± 0.301)/(13 ± 3) in GI; (1.678 ± 0.211)/(46 ± 9) in GII; and (0.941 ± 0.136)/(112 ± 21) in GIII. P-values between groups as: p < 0.005 in GI/GII; p < 0.0001 in GII/GIII and p < 0.00001 in GI/GIII. CONCLUSION: Light stimulates the cornea which is innervated by the trigeminal nerves. This experimental study indicates that the pupil remains mydriatic as the cornea is damaged by trigeminal ischemia following SAH and blocks the light flow.

New histopathological evidence for the relationship between hydromyelia and hydrocephalus following subarachnoid hemorrhage: An experimental study.

Objectives: Subarachnoid hemorrhage (SAH) is a serious pathology with a high death and morbidity rate. There can be a relationship between hydromyelia and hydrocephalus following SAH; however, this subject has not been well investigated. Materials and Methods: Twenty-four rabbits (3 ± 0.4 years old; 4.4 ± 0.5 kg) were used in this study. Five of them were used as the control, and five of them as the SHAM group. The remaining animals (n = 14) had been used as the study group. The central canal volume values at the C1-C2 levels, ependymal cells, numbers of central canal surfaces, and Evans index values of the lateral ventricles were assessed and compared. Results: Choroid plexus edema and increased water vesicles were observed in animals with central canal dilatation. The Evans index of the brain ventricles was 0.33 ± 0.05, the mean volume of the central canal was 1.431 ± 0.043 mm3, and ependymal cells density was 5.420 ± 879/mm2 in the control group animals (n = 5); 0.35 ± 0.17, 1.190 ± 0.114 mm3, and 4.135 ± 612/mm2 in the SHAM group animals (n = 5); and 0.44 ± 0.68, 1.814 ± 0.139 mm3, and 2.512 ± 11/mm2 in the study group (n = 14). The relationship between the Evans index values, the central canal volumes, and degenerated ependymal cell densities was statistically significant (P < 0.05). Conclusions: This study showed that hydromyelia occurs following SAH-induced experimental hydrocephalus. Desquamation of ependymal cells and increased cerebrospinal fluid secretion may be responsible factors in the development of hydromyelia.

The Enigma of Basilar Artery Dissections Secondary to Vasospasm following Subarachnoid Hemorrhage; Exploration of the Unknown Effect of Superior Cervical Ganglia: A Preliminary Experimental Study.

BACKGROUND: Life-threatening basilar artery dissection (BAD) can be seen following subarachnoid hemorrhage (SAH), but it is not clear whether subarachnoid hemorrhage causes dissection, or not. This study aims to investigate the relationship between, degenerative changes in the superior cervical ganglia and the dissection rate of the basilar artery. MATERIAL AND METHOD: In this article, after three weeks of experimental SAH, animals were decapitated. 18 rabbits were divided into three groups, according to their vasospasm indexes. The basilar arteries were examined by anatomical and histopathological methods. RESULTS: Basilar dissection with high vasospasm index value (VSI>3) was detected in six animals (G-I, n=6); severe basilar edema and moderate vasospasm index value (VSI>2.4) in seven rabbits (G-II, n=7) and slight vasospasm (VSI<1.5) index value in five subjects (G-III, n=5) was detected. The degenerated neuron densities (n/mm3) of the superior cervical ganglia were detected as 12±4 in G-I, 41±8 in G-II; and 276±78 in G-III. The dissected surface values/lumen values were calculated as (42±1)/(64±11) in G-I; (21±6)/(89±17) in G-II; and (3±1)/(102±24) in G-III. If we look at these ratios as a percentage: 62%in G-I, 23% in G-II, and 5% in G-III. CONCLUSION: Inverse relationship between the degenerated neuron densities (n/mm3) of the superior cervical ganglia and the dissected surface values basilar artery was observed. The common knowledge is that basilar artery dissection may lead to SAH, however, this study indicates that SAH is the cause of basilar artery dissection.

Effect of modified clivoaxial angle on surgical decision making and treatment outcomes in patients with Chiari malformation type 1.

Introduction: Chiari malformation type 1 (CM1), a complex pathological developmental disorder of the craniovertebral junction, is typically characterized by herniation of the cerebellar tonsils from the foramen magnum. Treatment using posterior fossa decompression alone without taking the ventral cervico-medullary compression into consideration may lead to unsatisfactory treatment outcomes. The current study evaluated the utility of the modified clivoaxial angle (MCAA) in assessing ventral compression and also examined its effect on treatment outcomes. Method: This retrospective study included 215 adult patients who underwent surgical treatment for CM1 at one medical center over a 10-year period. The following surgical techniques were used to decompress the posterior fossa: (a) PFD: bone removal only; (b) PFDwD: bone removal with duraplasty; and (c) CTR: cerebellar tonsil resection. The morphometric measurements of the craniovertebral junction (including MCAA) were recorded using preoperative images, and the postoperative clinical status was evaluated using the Chicago Chiari outcome scale (CCOS). Results: MCAA was positively correlated with the CCOS score and also independently predicted treatment outcome. To enable Receiver operating characteristic (ROC) curve analysis of CCOS scores, the patients were divided into three groups based on the MCAA cut-off values, as follows: (a) severe (n = 43): MCAA ≤ 126; (b) moderate (n = 86): 126 < MCAA ≤ 138; and (c) mild (n = 86): MCAA > 138. Group a exhibited severe ventral cervico-medullary compression (VCMC), and their CCOS scores for the PFD, PFDwD, and CTR groups were 11.01 ± 1.2, 11.24 ± 1.3, and 13.01 ± 1.2, respectively (p < 0.05). The CCOS scores increased with widening of the MCAA angle in all surgical groups (p < 0.05). Furthermore, patients with mild MCAA (>138°) exhibited 78% regression of syringomyelia, and this was significantly greater than that observed in the other groups. Discussion: MCAA can be used in the selection of appropriate surgical techniques and prediction of treatment outcomes, highlighting the importance of preoperative evaluation of ventral clivoaxial compression in patients with CM1.

Supramarginal Gyrus and Angular Gyrus Subcortical Connections: A Microanatomical and Tractographic Study for Neurosurgeons.

Background and Objectives: This article aims to investigate the subcortical microanatomy of the supramarginal gyrus (SMG) and angular gyrus (AnG) using a microfiber dissection technique and diffusion tensor imaging (DTI)/fiber tractography (FT). The cortical and subcortical structures of this region are highly functional, and their lesions often present clinically. For this reason, the possibility of post-surgical deficits is high. We focused on the supramarginal gyrus and the angular gyrus and reviewed their anatomy from a topographic, functional and surgical point of view, and aimed to raise awareness especially for neurosurgeons. Methods: Four previously frozen, formalin-fixed human brains were examined under the operating microscope using the fiber dissection technique. Four hemispheres were dissected from medial to lateral under the surgical microscope. Brain magnetic resonance imaging (MRI) of 20 healthy adults was examined. Pre-central and post-central gyrus were preserved to achieve topographic dominance in dissections of brain specimens. Each stage was photographed. Tractographic brain magnetic resonance imaging of 10 healthy adults was examined radiologically. Focusing on the supramarginal and angular gyrus, the white matter fibers passing under this region and their intersection areas were examined. These two methods were compared anatomically from the lateral view and radiologically from the sagittal view. Results: SMG and AnG were determined in brain specimens. The pre-central and post-central gyrus were topographically preserved. The superior and medial temporal gyrus, and inferior and superior parietal areas were decorticated from lateral to medial. U fibers, superior longitudinal fasciculus II (SLF II), superior longitudinal fasciculus III (SLF III), arcuat fasciculus (AF) and middle longitudinal fasciculus (MdLF) fiber groups were shown and subcortical fiber structures belonging to these regions were visualized by the DTI/FT method. The subcortical fiber groups under the SMG and the AnG were observed anatomically and radiologically to have a dense and complex structure. Conclusions: Due to the importance of the subcortical connections of SMG and AnG on speech function, tumoral lesions and surgeries of this region are of particular importance. The anatomical architecture of the complex subcortical structure, which is located on the projection of the SMG and AnG areas, was shown with a DTI/FT examination under a topographic dominance, preserving the pre-central and post-central gyrus. In this study, the importance of the anatomical localization, connections and functions of the supramarginal and angular gyrus was examined. More anatomical and radiological studies are needed to better understand this region and its connections.

Radiological and Clinical Follow-up of Alpha-D Cervical Disk Prosthesis.

Background: Fusion surgery is applied to prevent segmental instability after surgery for cervical disk herniation. Motion-sparing surgeries have been developed to prevent adjacent segment disease after fusion surgery. Total disk replacement, one of these methods, has been applied in the cervical region for more than 20 years. We aimed to investigate the medium-term radiological and clinical outcomes of patients who had received Alpha-D disk prosthesis after cervical disk surgery, in terms of incidence of heterotopic ossification (HO) and other complications. Methods: We included 33 patients (17 women and 16 men) diagnosed with single-level cervical disk herniation and who had received prosthesis after anterior discectomy. The average follow-up period was 36 (18-78) months. The patients were followed up postoperatively at month 4, year 1, and annually thereafter. Patients, who had Alpha-D cervical disk prosthesis (CDP) (Medikon, Turkey), were monitored via radiological (standard and dynamic X-ray) and clinical (visual analog scale [VAS] and neck disability index [NDI]) modalities. Dynamic X-ray images were evaluated by an independent radiologist for HO and prosthesis movement. Results: Mean patient age was 40 ± 6.88 years. HO was observed in 7 (21.21%) patients, 6 of which were men. Significant intersex differences were noted for HO and movement rates (p = 0.039). Clinically, the mean preoperative and post-operative NDI levels were 35.4 ± 3.9 and 4 ± 2, respectively, whereas the mean pre- and post-operative VAS levels were 7 ± 1 and 1 ± 1, respectively. There was a clinically significant postoperative improvement in all the patients. However, there was no significant difference between the patients with and without HO in terms of age, operation level, and mean pre- and postoperative VAS, and postoperative NDI levels (p > 0.05). Despite the fact that there was a significant difference (p = 0.038) in favor of patients without HO in terms of mean preoperative NDI levels, this was not considered clinically significant. Conclusion: In the present study, all the patients demonstrated clinically significant improvement following CDP surgery. HO rate after CDP surgery was 21.21% in the medium term, and movement was preserved in 5 of the 7 patients with partial HO. The fact that the CDP design was based on the one-to-one reproduction of the movement segment in the cervical spine, might account for the underlying cause of success. However, these good results in the medium term may change in cases with long-term clinical follow-up.

The role of ONSD in the assessment of headache associated with Chiari malformation type 1.

Background: Cough associated headache is the most common symptom in Chiari malformation type 1 (CM1). However, its pathophysiology and treatment are not clear. The aim of this study was to investigate the relationship between optic nerve sheath diameter (ONSD), an indicator of intracranial pressure, and headache and to investigate its predictive value on postoperative outcome. Methods: In symptomatic CM1 patients, craniovertebral junction morphometric measurements and ONSD measurements were made from preoperative MR images, and headache intensities and characteristics were evaluated. After different surgical procedures, the clinical characteristics of the patients were evaluated according to the Chicago Chiari Outcome Scale, the change in headache intensity was assessed and the relationship with ONSD was evaluated. Results: Preoperative headache intensity was significantly correlated with ONSD measurement (p < 0.01). Modified clivoaxial angle and ONSD were independent predictors of postoperative clinical outcome (p < 0.01). The procedure that achieved the greatest surgical enlargement of the foramen Magnum stenosis provided the best clinical outcome. Postoperative reduction in headache intensity and ONS diameter were correlated (p < 0.01). Conclusion: The fact that ONSD is found to be wide in the preoperative period in CM1 patients indicates that the intracranial pressure is permanently high. This diameter increase is correlated with headache and is a valuable guide in the selection of the appropriate treatment method.

Clinical and radiological analysis of the effects of three different lumbar transpedicular dynamic stabilization system on disc degeneration and regeneration.

Objective: This study aims to assess the clinical outcomes of three transpedicular dynamic systems in treating degenerative disc disease and evaluate their impact on both clinical and radiological aspects of the operated and adjacent segments. Materials and methods: A total of 111 patients who underwent posterior transpedicular short-segment dynamic system procedures for treatment of degenerative disc disease were included. The patients were categorized into three groups, namely, Group 1 (Dynesys system, n = 38), Group 2 (Safinaz screw + PEEK rod, n = 37), and Group 3 (Safinaz screw + titanium rod, n = 36). Disc regeneration in the operated segment and disc degeneration in the operated, upper, and lower adjacent segments were assessed using the Pfirrmann Classification. Results: Postoperatively, a statistically significant difference was observed in visual analog scale and Oswestry Disability Index scores (p < 0.001). However, no statistically significant difference was seen in disc degeneration/regeneration and degeneration scores of the upper and lower adjacent segments between the preoperative and postoperative groups (p = 0.763, p = 0.518, p = 0.201). Notably, a positive effect on disc regeneration at the operated level (32.4%) was observed. No significant differences were found between the groups in terms of operation rates, screw loosening, and screw breakage after adjacent segment disease (p > 0.05). Conclusion: In patients without advanced degeneration, all three dynamic systems demonstrated the ability to prevent degeneration in the adjacent and operated segments while promoting regeneration in the operated segment. Beyond inhibiting abnormal movement in painful segments, maintaining physiological motion and providing axial distraction in the operated segment emerged as key mechanisms supporting regeneration.

Preoperative Magnetic Resonance Imaging Abnormalities Predictive of Lumbar Herniation Recurrence After Surgical Repair.

OBJECTIVE: There are currently no standard criteria for evaluating the risk of recurrent disk herniation after surgical repair. This study investigated the predictive values of 5 presurgical imaging parameters: paraspinal muscle quality, annular tear size, Modic changes, modified Phirrmann disk degeneration grade, and presence of sacralization or fusion. METHODS: Between 2015 and 2018, 188 patients (89 female, 99 male, median age 50) receiving first corrective surgery for lumbar disk herniation were enrolled. Microdiskectomy was performed in 161 of these patients, and endoscopic translaminar diskectomy approach was performed in 27 patients. Clinical status was evaluated before surgery and 4, 12, and 24 months post surgery using a visual analog scale, Oswestry Disability Index, and Short Form 36. RESULTS: Recurrent disk herniation was observed in 21 of 188 patients. Seventeen of the recurrent disk herniations were seen in those who underwent microdiskectomy and 4 in those who underwent endoscopic translaminar diskectomy. There were significant differences in visual analog scale, Oswestry Disability Index, and Short Form 36 scores at 4, 12, and 24 months between patients with recurrence and the 167 no-recurrence patients. The median annular tear length was significantly greater in patients with recurrence than without recurrence. In addition, there were significant differences in recurrence rate according to Modic change type distribution, sacralization or fusion presence, Pfirmann disk; degeneration grade distribution, dichotomized annular tear size, dichotomized Modic change; and type and simplified 3-tier muscle degeneration classification distribution. CONCLUSIONS: Patients with poor clinical scores and recurrence exhibited additional radiologic abnormalities before surgery, such as poor paraspinal muscle quality, longer annular tears, higher Modic change type, higher modified Phirrmann disk degeneration grade, and sacralization or fusion. This risk evaluation protocol may prove valuable for patient selection, surgical planning, and choice of postoperative recovery regimen.

Protective Felix Culpa Effect of Superior Sympathetic Cervical Ganglion Degenerations on Prevention of Basilar Artery Spasm After Subarachnoid Hemorrhage: A Preliminary Experimental Study.

BACKGROUND: Posterior cerebral blood flow is regulated by the basilar arteries (BAs). Vasospasm of BAs can occur after subarachnoid hemorrhage (SAH). Superior cervical sympathetic ganglia (SCG) fibers have a vasoconstrictor effect on the BA. We aimed to investigate the relationship between the degenerated neuron density of the SCG and the severity of BA vasospasm after experimental SAH. METHODS: Twenty-four rabbits were used. Five were used as the control group, and 5 were used as the sham group. Experimental SAHs were performed in the remaining 14 animals (study group) by injecting homologous blood into the cisterna magna. After 3 weeks of injection, neuron densities of SCG and the severity of BA vasospasm index values (VSI) were examined histopathologically and compared statistically. RESULTS: The mean VSI was 0.669 ± 0.1129 in the control group, 0.981 ± 0.159 in the sham group, and 1.512 ± 0.298 in the study group. The mean degenerated neuronal density of SCG was 436 ± 79/mm3 in severe vasospasm (n = 3), 841 ± 101/mm3 in moderate vasospasm (n = 4), and 1.921 ± 849/mm3 in the less vasospasm detected animals (n = 6). CONCLUSIONS: This study shows an inverse relationship between the degenerated neuronal density in the SCG and VSI values. This finding indicates a diminished sympathetic input from the SCG, resulting in a beneficial effect (the felix culpa) by dilating the lumen diameter of the BA, so SCG degeneration after SAH protects the BA spasm.

Dry Mouth Caused by Facial Nerve Ischemia due to Subarachnoid Hemorrhage: An Experimental Study.

OBJECTIVE: Parasympathetic network damage results in facial nerve damage, sublingual ganglion degeneration, sublingual gland dysfunction, and dry mouth. In this study, subarachnoid hemorrhage (SAH) was considered to be the cause of dry mouth. METHODS: We assessed 23 hybrid rabbits, including 5 control (group 1, Control). One milliliter of serum saline was injected into the cisterna magna of 5 animals (group 2). SAH was induced by injecting 1 mL of autologous blood into the cisterna magna of 13 animals (group 3). The animals were killed after 3 weeks of induction. The animals' sublingual ganglion and sublingual gland were excised for histopathological examination. The number of degenerated cells in the sublingual ganglion, secretory vesicles, and secretory granules in the sublingual gland that contain salivary components were estimated using Sequential Window Acquisition of All Theoretical Mass Spectra data analysis. The values were compared by the Mann-Whitney U-test. RESULTS: The numbers of secretory vesicles in the sublingual gland were 5.3 ± 1.1 × 103 (group 1), 4.23 ± 0.45 × 103 (group 2), and 1.56 ± 0.22 × 103 (group 3); the numbers of secretory vesicles containing saliva in the sublingual gland were 324 ± 12.18 (group 1), 263 ± 36.23 (group 2), and 114 ± 23.14 (group 3); and the numbers of degenerated cells in the sublingual ganglion were 11 ± 3/mm3 (group 1), 98.43 ± 15.54/mm3 (group 2), and 346 ± 12.28/mm3 (group 3) (P < 0.05). CONCLUSIONS: Clinical findings in infection and diseases such as Sjögren syndrome, aseptic meningitis, and SAH are similar. However, until now, SAH has not been demonstrated experimentally to cause dry mouth. Discovering that SAH might cause dry mouth might prevent unnecessary use of antibiotics and decrease morbidity due to the wrong or late diagnosis.