Suprafloccular transhorizontal fissure approach to the cerebellopontine angle: an anatomical study with case series.

The suprafloccular transhorizontal fissure approach is a modified variant of the classical retrosigmoid approach option to be chosen for cerebellopontine angle lesions. In this study, we aimed to demonstrate a previously described but not widely used method, the suprafloccular transhorizontal fissure approach with anatomical dissection on the cadaver, accompanied by a case presentation with the largest clinical series in the literature. Klingler's protocol was used to prepare 8 silicone injected and 8 non-silicone injected human hemispheres. A total of 210 patients who underwent surgery in the cerebellopontine angle between 2019 and 2022 were evaluated in our clinic. Of these, the suprafloccular transhorizontal fissure approach was applied in 33 patient, and it was successful in 26 patient, but this approach could not be achieved in 7 patients. The transhorizontal fissure is a fissure in the cerebellum located between the superior semilunar lobule and the inferior semilunar lobule. In the 26 patients we operated with the suprafloccular transhorizontal fissure approach, there was no need for retraction and no complications developed. However, in 7 patients, this fissure could not be dissected due to adhesions. Suprafloccular approach is an alternative to the classical retrosigmoid approach in tumours smaller than 2 cm, medially localised with little cerebellar oedema and neurovascular compression syndrome. Because in this approach, no cerebellum retraction is required, vascular structures are better preserved and the surgical time is shortened. This approach can be applied in smaller tumours than 2 cm when the sulcal anatomy is appropriate.

Glossopharyngeal neuralgia as initial symptom in combined hyperactive dysfunction syndrome: case report.

OBJECTIVES: Hyperactive dysfunction syndrome (HDS) is defined as symptoms arising from overactivities in cranial nerves, like trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia (GPN). A combination of these cranial nerve neuralgias, that might or might not occur in one or both sides, either synchronously, or metachronously is called combined hyperactive dysfunction syndrome (CHDS). CASE PRESENTATION: We presented a 73 years-old male patient with CHDS presenting with GPN as the initial symptom, with total relief from GPN, TN, and HFS after microvascular decompression. Up to date, only nine patients have been reported in the literature with symptomatic. CONCLUSIONS: TN-HFS-GPN. Our case is the first case with GPN as the initial symptom. The combination of arterial and venous origin of the offending vessels makes the case picturesage.

Effects of pirfenidone on experimental head injury in rats.

Traumatic brain injury (TBI) continues to be a significant public healthcare concern. Neuroinflammation that occurs in the secondary phase of TBI leads to cognitive and physical dysfunction. A number of therapeutic modalities have been evaluated in an attempt to find a suitable treatment. The only drug approved for the treatment of idiopathic pulmonary fibrosis, pirfenidone, has been evaluated for its antifibrotic, anti-inflammatory, and anti-oxidant properties for various disorders, but this is the first study to examine its effects in an experimental TBI model. Twenty-four Wistar rats were randomly divided into three groups: control, trauma, and pirfenidone. The two latter groups underwent experimental diffuse cortical injury mimicking TBI. Neurological assessment was performed using the Garcia test, histological analysis was performed to examine neuroprotective and anti-inflammatory effects, and biochemical analyses of neuron-specific enolase (NSE), S-100B, caspase-3, and thiobarbituric acid reactive substances were performed. The pirfenidone group had a better Garcia test score (P=0.001), an increased anti-inflammatory effect (P<0.001), and an enhanced neuroprotective effect (P=0.007) along with decreased NSE, S100B, and TBARS levels compared to the trauma group. However, pirfenidone did not show a beneficial effect on caspase-3 levels. Pirfenidone may help decrease mortality and morbidity rates after TBI through its anti-inflammatory and antioxidant effects.

Influence of posterior pedicle screw fixation at L4-L5 level on biomechanics of the lumbar spine with and without fusion: a finite element method.

BACKGROUND: Posterior pedicle screw (PS) fixation, a common treatment method for widespread low-back pain problems, has many uncertain aspects including stress concentration levels, effects on adjacent segments, and relationships with physiological motions. A better understanding of how posterior PS fixation affects the biomechanics of the lumbar spine is needed. For this purpose, a finite element (FE) model of a lumbar spine with posterior PS fixation at the L4-L5 segment level was developed by partially removing facet joints (FJs) to imitate an actual surgical procedure. This FE study aimed to investigate the influence of the posterior PS fixation system on the biomechanics of the lumbar spine before and after fusion by determining which physiological motions have the most increase in posterior instrumentation (PI) stresses and FJ loading. RESULTS: It was determined that posterior PS fixation increased FJ loading by approximately 35% and 23% at the L3-L4 adjacent level with extension and lateral bending motion, respectively. This increase in FJ loading at the adjacent level could point to the possibility that adjacent segment disease has developed or progressed after posterior lumbar interbody fusion. Furthermore, analyses of peak von Mises stresses on PI showed that the maximum PI stresses of 272.1 MPa and 263.7 MPa occurred in lateral bending and flexion motion before fusion, respectively. CONCLUSIONS: The effects of a posterior PS fixation system on the biomechanics of the lumbar spine before and after fusion were investigated for all physiological motions. This model could be used as a fundamental tool for further studies, providing a better understanding of the effects of posterior PS fixation by clearing up uncertain aspects.

A Rare Entity in the Lumbar Epidural Region: T-Cell Lymphoblastic Lymphoma.

BACKGROUND: T-cell lymphoblastic lymphoma is a rare disease and an aggressive neoplasm of precursor lymphoblasts. We present a case of lumbar epidural T-cell lymphoblastic lymphoma which appeared with clinical features of epidural spinal cord compression. METHODS: A 38-year-old male patient presented with weakness in the lower extremities and newly developed urinary incontinence. His medical history included precursor T-cell acute lymphoblastic leukemia and treatment with allogeneic bone-marrow transplantation 5 years previously. Spinal magnetic resonance imaging (MRI) revealed an epidural mass lesion at L2-L4 levels and there was no sign of leukemia or lymphoma in clinical, laboratory, and radiological examinations. Surgery was planned for obtaining diagnostic material. Decompressive laminectomy and subtotal excision of the tumor were performed. RESULTS: At surgery, the tumor consisted of yellow-colored and hypovascular soft tissue fragments. It was encircling the spinal cord and spreading through the left L3 foramen. The patient underwent adjuvant chemoradiotherapy after the histopathological evaluation. At 2-month follow-up, the patient was able to walk without assistance, but the urinary incontinence was the same. At 5-month follow-up, the disease progressed, and the patient passed away because of infective endocarditis. CONCLUSION: Spinal lymphomas may display its characteristic "wrap-around" fashion in the MRI. In this report, we shared the microsurgical appearance of this fashion. As the lymphomas are chemoradiosensitive tumors, the treatment should be managed with a multidisciplinary approach.

Two-Dimensional Video of Surgery on Trochlear Schwannoma.

Trochlear schwannoma in the absence of neurofibromatosis is a rare entity.1 These schwannomas originate usually from the intradural cisternal part of the nerve and expand in the ambient and interpeduncular cisterns as well as inferiorly in the upper part of the cerebellopontine cistern.2 This case involves a rare pontomesencephalic lesion removed successfully via the simple retrosigmoid suboccipital route (Video 1). A 49-year-old woman presented to our institute with decreased sensation on the left side of her body for 2 months. Neurologic examination revealed left hemihypoesthesia. Cranial magnetic resonance imaging revealed a lobulated, heterogeneously enhanced cystic tumor within the right ambient cistern compressing the adjacent midbrain and extending to the cerebellopontine angle. After obtaining consent for surgery, the patient underwent a right suboccipital retrosigmoid approach for exploration and resection of the lesion. During the operation, it was determined that the tumor originated from the trochlear nerve. Nerve-sparing surgery was performed with intraoperative neuromonitoring including cranial nerve V, VII, X, XI, and XII electromyography and muscle motor evoked potentials. Gross total resection of the tumor was achieved. In the early postoperative period, the patient's eye movements were normal in all directions. The patient did not have any visual problems and experienced improvement in hemihypoesthesia. She was discharged on the third postoperative day. Pathologic examination confirmed diagnosis of schwannoma. At 2 months after surgery, the patient's eye movements were intact, and trochlear nerve palsy did not occur. The patient gave written informed consent for surgery and publication of this case report.

Investigation of toggling effect on pullout performance of pedicle screws.

Objective of this study is to assess the pullout performance of various pedicle screws in different test materials after toggling tests comparatively. Solid core, cannulated (cemented), novel expandable and solid-core (cemented) pedicle screws were instrumented to the polyurethane foams (Grade 10 and Grade 40) produced in laboratory and bovine vertebra. ASTM F543 standard was used for preparation process of samples. Toggling tests were carried out. After toggling test procedures, pullout tests were performed. Load versus displacement graph was recorded, and the ultimate pullout force was defined as the maximum load (pullout strength) sustained before failure of screw. Anteriosuperior and oblique radiographs were taken from each sample after instrumentation in order to examine screw placement and cement distribution. The pullout strength of pedicle screws decreased after toggling tests with respect to the initial condition. While the cemented solid-core pedicle screws had the highest pullout strength in all test materials, they had the highest strength differences. The cemented solid-core pedicle screws had decrement rates of 27% and 16% in Grade 10 and Grade 40, respectively. There are almost same decrement rate (between 5.5% and 6.5%) for all types of pedicle screws instrumented to the samples of bovine vertebra. The pullout strengths of novel expandable pedicle screws in both of early period and after toggling conditions were almost similar, in other words, the decrement rates of it were lower than other types. According to the data collected from this study, polymethylmethacrylate augmentation significantly decreases pullout strength following the toggling loads. Higher brittleness of cured polymethylmethacrylate has adverse effect on the pullout strength. Although augmentation is an important process for enhancing pullout strength in early period, it has some disadvantages for preserving stabilization in a long time. Expandable pedicle screw with polyetheretherketone shell may be good alternative to polymethylmethacrylate augmentation on both primer stabilization and long-term loading application with toggling.

Histopathologic Analysis of Tamoxifen on Epidural Fibrosis.

BACKGROUND: Epidural fibrosis is a challenging topic in spinal surgery. This phenomenon constitutes one of the main reasons behind postlaminectomy syndrome or failed back surgery syndrome, which leads to persistent back and leg pain in association with compression and/or stretching the nerve root or the dura. The exact mechanism of action in epidural fibrosis is complex and remains uncertain. Excessive deposition of collagen, fibronectin, and dermatan sulfate, known as the "extracellular matrix," and decrease of tissue cellularity results in epidural fibrosis. The most investigated and important actor in epidural fibrosis as well as in other forms of aberrant wound healing is presumed to be transforming growth factor-1ß formation. Tamoxifen (TAM), a synthetic nonsteroidal antiestrogen used in breast cancer, is also effective in inhibiting fibroblast proliferation via downregulation of transforming growth factor-1ß. METHODS: Twenty-four adult male rats were randomly divided into 3 groups. Laminectomy was the sole intervention in the control group. Spongostan was placed in the operation lodge after laminectomy in the second group. In the treatment group, TAM was administrated orally after laminectomy. Epidural fibrosis, dural thickness, inflammatory response, and arachnoidal involvement were evaluated and graded histopathologically. RESULTS: Epidural fibrosis, dural thickness, and inflammatory response in the subjects treated with TAM were significantly less than in the control and Spongostan group and the differences were statistically significant. Although arachnoidal involvement was observed in a subject in the TAM group, the differences between all groups weren't statistically significant. CONCLUSIONS: Tamoxifen reduced epidural fibrosis, dural thickness, and inflammatory response after laminectomy in rats.

Effects of Resveratrol on Inflammation and Apoptosis After Experimental Spinal Cord Injury.

AIM: To determine the effects of resveratrol on inflammation and apoptosis after experimental spinal cord injury (SCI). MATERIAL AND METHODS: Eighteen Sprague-Dawley rats were randomly divided into three groups. All groups underwent thoracic laminectomy. The first group received no other intervention. The second and third groups suffered SCI via the aneurysm clip compression method, and additionally the third group received resveratrol. After euthanizing the rats, immunohistochemical analysis and biochemical parameters of tumor necrosis factor alpha (TNF-?) and interleukin (IL)-1? were measured. RESULTS: The resveratrol group had statistically significant lower levels of TNF-?, IL -1?, and terminal deoxynucleotidyl transferasemediated dUTP nick-end labeling (TUNEL) positive cells and higher number of glial and motor neuron cells. CONCLUSION: Resveratrol proves to have remarkable neuroprotective effects on SCI in an experimental model in addition to its proven cardioprotective effects.

Massive Primary Intraventricular Hemorrhage Due to Idiopathic Lateral Posterior Choroidal Artery Aneurysm: Case Illustration.

Peripheral aneurysms of the lateral posterior choroidal artery are rare and mostly in association with vascular and occlusive pathologies such as moyamoya disease. To the best of our knowledge, pure lateral posterior choroidal artery aneurysms without association of any other vascular diseases are unique and only 3 cases have been reported in the literature.

Pullout performance comparison of novel expandable pedicle screw with expandable poly-ether-ether-ketone shells and cement-augmented pedicle screws.

Aim of this study is to assess the pullout performance of various pedicle screws in different test materials. Polyurethane foams (Grade 10 and Grade 40) produced in laboratory and bovine vertebrae were instrumented with normal, cannulated (cemented), novel expandable and normal (cemented) pedicle screws. Test samples were prepared according to the ASTM F543 standard testing protocols and surgical guidelines. To examine the screw placement and cement distribution, anteriosuperior and oblique radiographs were taken from each sample after insertion process was completed. Pullout tests were performed in an Instron 3369 testing device. Load versus displacement graphs were recorded and the ultimate pullout force was defined as the maximum load (pullout strength) sustained before failure of screw. Student's t-test was performed on each group whether the differences between pullout strength of pedicle screws were significant or not. While normal pedicle screws have the lowest pullout strength in all test materials, normal pedicle screws cemented with polymethylmethacrylate exhibit significantly higher pullout performance than others. For all test materials, there is a significant improvement in pullout strength of normal screws by augmentation. While novel expandable pedicle screws with expandable poly-ether-ether-ketone shells exhibited lower pullout performance than normal screws cemented with polymethylmethacrylate, their pullout performances in all groups were higher than the ones of normal and cannulated pedicle screws. For all test materials, although cannulated pedicle screws exhibit higher pullout strength than normal pedicle screws, there are no significant differences between the two groups. The novel expandable pedicle screws with expandable poly-ether-ether-ketone shells may be used instead of normal and cannulated pedicle screws cemented with polymethylmethacrylate due to their good performances.

Effects of Topical Cova™, Tisseel® and Adcon® Gel Application on the Development of Spinal Peridural Fibrosis: An Experimental Study in Rats.

AIM: Leptomeningeal adhesions and fibrosis in the spinal peridural space are the most common causes of post-laminectomy syndrome. Fibrin sealant agents and membrane barriers are commonly used for hemostasis and sealing purposes in spinal surgery. Peridural fibrosis may be a risk of the usage of these topical agents. In this study, we aimed to compare the effects of Cova ™, Tisseel® and Adcon ® Gel on the development of spinal peridural fibrosis in the experimental rat model. MATERIAL AND METHODS: Thirty-two Sprague Dawley female rats were randomly divided into 4 groups. Groups were constituted as group 1; Cova™ group (laminectomy+Cova™), group 2; Tisseel® group (laminectomy+Tisseel®), group 3; Adcon®Gel group (laminectomy + Adcon®Gel), group 4; control group (laminectomy only). Six weeks after laminectomy, spinal columns were removed en bloc between L1 and L4 vertebrae. Peridural fibrosis was evaluated histologically and the results were compared statistically. RESULTS: Statistically significant reduction of peridural fibrosis was achieved in groups 1, 2, and 3 when compared with the control group (p < 0.05). Our data revealed a statistically significant difference between group 1 and group 3 (p < 0.05). When we compared with group 2 and 3, the fibrosis grades were not different between these two groups (p > 0.05). CONCLUSION: Fibrin sealant agent Tisseel® and membrane barrier Cova™ do not enhance peridural fibrosis following laminectomy. Cova™ and Tisseel® may be appropriate for hemostasis and leakage prevention during the spinal surgery and it is safe to leave these materials on the operation surface.

Subarachnoid Hemorrhage Presenting with Seizure due to Cerebrospinal Fluid Leakage after Spinal Surgery.

Cerebrospinal fluid leakage may commonly occur during spinal surgeries and it may cause dural tears. These tears may result in hemorrhage in the entire compartments of the brain. Most common site of such hemorrhages are the veins in the cerebellar region. We report a case of hemorrhage, mimicking aneurysmal subarachnoid hemorrhage due to a cerebrospinal fluid leakage following lumbar spinal surgery and discuss the possible mechanisms of action.

Experimental Evaluation of the Developmental Mechanism Underlying Fractures at the Adjacent Segment.

BACKGROUND: Compression fractures at adjacent mobile segments have been reported as adjacent segment disease under trauma in several studies. In this study, the occurrence of fractures at the adjacent segment was evaluated experimentally under trauma. METHODS: Static testing of different fixation systems was performed to show their biomechanical performances. The ovine vertebrae fixed with rigid, dynamic, and semirigid systems were used as test samples. The stiffness values of the systems were obtained by testing the vertebrectomy models under compression bending, lateral bending, and torsion tests. In addition, their effects on the adjacent segments were experimentally evaluated within a drop mechanism. A free-fall drop mechanism was designed and manufactured. Next, 3.5-kg, 5-kg, and 7-kg weights were released from 1 m above the test samples to generate compression fractures. The occurrence of compression fractures was observed with the use of radiograph of test samples, which were obtained before and after the drop test. RESULTS: Dynamic and semirigid systems have advantages compared with rigid systems as the result of their lower stiffness values. Radiographs showed that epiphysis fractures occurred at fixed and adjacent mobile segments, which were fixed with semirigid fixation. In addition, dynamic fixation well preserved the fixed and adjacent mobile segments under trauma. CONCLUSIONS: The dynamic system with a polyetheretherketone rod can better preserve both adjacent and fixed segments. However, because of the cantilever beam effect, the semirigid system exhibits a great disadvantage.

A critical appraisal of the North American Spine Society guidelines with the Appraisal of Guidelines for Research and Evaluation II instrument.

BACKGROUND CONTEXT: The North American Spine Society (NASS) publishes clinical guidelines that are taken into consideration worldwide by clinicians who have a special interest in spinal surgery. The Appraisal of Guidelines for Research and Evaluation (AGREE) II is the second version of the original AGREE instrument to assess the quality of guidelines in terms of development process. This appraisal aims to evaluate each individual NASS guideline using AGREE II tool to demonstrate its methodologic robust and weakness. PURPOSE: To evaluate the quality of the clinical practice guidelines published by the NASS. STUDY DESIGN: Four appraisers used the AGREE II guideline evaluation instrument to evaluate the NASS guidelines. METHODS: All six guidelines available on the NASS web site as of July 1, 2014 were evaluated. Four reviewers independently assessed these guidelines using the AGREE II instrument. The instrument standardizes the quantitative assessment of quality for a guideline's development process across six domains that include: scope and purpose, stakeholder involvement, rigor of development, clarity and presentation, applicability, and editorial independence. Additionally, each reviewer rated the overall quality of the guidelines. RESULTS: Overall results for the AGREE II domains across all six guidelines were: scope and purpose (median score, 94.4%), stakeholder involvement (median score, 56.9%), rigor of development (median score, 91.7%), clarity of presentation (median score, 94.4%), applicability (median score, 60.9%), and editorial independence (median score, 71.9%). CONCLUSIONS: Our study showed that the quality of the NASS guidelines needs some improvement. There is a critical need for broader stakeholder involvement including patient representatives and health economists. Consideration of resource implications and monitoring process and standardization of how recommendations are implemented need to be improved. Studies analyzing facilitators and barriers would be helpful for future NASS guidelines.

Subarachnoid, subdural and interdural spaces at the clival region: an anatomical study.

AIM: We aimed to show the significance of the anterior pontine membrane as a determining structure between the subdural and subarachnoid space in the clival region. MATERIAL AND METHODS: Five adult cadaver heads and five cerebral hemispheres were used. The skull vault and hemipheres were removed by sectioning through the pontomesencephalic junction. Five other heads hemispheres were removed but the arachnoid membrane was protected and the cerebral side of the clival dura mater was dissected. In another specimen, the dural porus of the abducens nerve was sectioned for histological evaluation. Three cases of hematoma at the clivus were presented to support our findings. RESULTS: The anterior pontine membrane is the arachnoid membrane forming the anterior wall of the prepontine cistern with its lateral extension at the skull base. This membrane forms the subdural and subarachnoid spaces by forming a barrier between the clival dura mater and neurovascular structures of the brainstem. There were rigid fibrous trabeculations between both cerebral and periosteal dural layers forming the basilar plexus as the interdural space in the clivus. CONCLUSION: The anterior pontine membrane separates the subdural and subarachnoid spaces at the clival region. The hematomas of the clival region require to be evaluated with consideration given to the existance of the subdural space.

Symptomatic spontaneous pneumocephalus after spinal fusion for spondylolisthesis.

Symptomatic spontaneous pneumocephalus after a spinal fusion for spondylolisthesis without injury to the dura mater is rare. There are only a few reports of tension pneumocephalus after spinal operations published in English. We present a patient who developed tension pneumocephalus without recognised dural injury during surgery. CT cisternography and MRI showed no anatomical defects that could have caused the pneumocephalus. We suggest that spontaneous pneumocephalus without dural injury may occur after a spondylolisthesis operation because of increased intra-abdominal pressure, and thus may be avoided by the careful management of abdominal pressure.

Isolated paralysis of glossopharyngeal and vagus nerve associated with type II occipital condyle fracture: case report.

INTRODUCTION: Occipital condyle fractures (OCFs) can occasionally be complicated with lower cranial nerve palsies. DISCUSSION: Isolated 9th and 10th cranial nerve palsies following OCF are very rare. To our knowledge, we report the first case of an early onset of 9th and 10th cranial nerve palsies with an early full recovery in short period of time and discuss the probable mechanism of isolated nerve palsy in the light of the relevant literature.