Medial pontine area: Safe entry to the brainstem as a cut above the rest.

AIM: The safe entry zones for ventral brainstem (BS) should ideally be away from the cranial nerve fibers and their nuclei, contain the least amount of fibers, and should be apart from the functional descending and ascending tracts. Specifically, the management of intrinsic lesions located along the anterior surface of the pons has still been controversial, challenging, and worrisome. Our study aims to revisit the fiber-based anatomy of the medial pontine area (MPA), what is presumed to be one of the most commonly used BS safe entry zones in neurosurgery. MATERIAL AND METHODS: The six brainstems were kept in 10% formalin solution for at least two months in accordance with the protocol proposed by Klingler J. and Ludwig E. After the arachnoid mater, pia mater, and vascular structures were removed, samples were frozen at -16°C for at least two weeks. White matter (WM) pathways of the BS were explored by gradually using fiber dissections under the surgical microscope. RESULTS: Safe entry zones of the BS were defined and explored with special emphasis on the ventral pontine region and pontomesancephalic junction. The MPA formed a safe surgical field due to the distinct nature of scarcity of fibers on the anterior surface of the pons. MPA's perfect location in between the descending corticospinal tracts and its secure depth back to the anterior limit of the medial lemniscus constructed a surgical asylum for BS safe entry zones. CONCLUSION: The pivotal position of the MPA has the potential to offer a combined surgical path with superiorly located BS entry zones, thus creating a wider surgical area. Entry to the BS through the MPA increases the surface area that can be accessed in the ventral pons and can be combined with the other described perioculomotor safe regions. Our study may prove helpful for endoscopic endonasal transclival interventions to intrinsic pontine lesions safer.

Improving the Visualization of Superior Longitudinal Fascicule-2 and Superior Longitudinal Fascicule -3 Using Photoshop Filters.

BACKGROUND AND OBJECTIVES: Several studies are currently exploring the anatomical origins of superior longitudinal fascicule (SLF) 2 and SLF-3, which are components of the frontoparietal network. This study aimed to achieve optimum visualization of the anatomical corridors of these fibers using Photoshop filters. METHODS: Four postmortem brain hemispheres were dissected in accordance with the method proposed by Klingler and Ludwig. Dissections were performed under a surgical microscope (Carl Zeiss AG, Oberkochen, Germany) at 4× and 40× magnification. All dissections were documented at each stage using a professional digital camera (Canon EOS 600D) with a macro 100 mm lens (Canon), ring-flash attachment (Canon), and professional tripod (Manfrotto 808 C4). We aimed to improve the visual quality of the images by avoiding monotone using various the features and filters in Photoshop. RESULTS: SLF-2 originates from the angular gyrus (Brodmann area [BA] 39) in the right hemisphere and has been observed to project fibers from BA7 and BA19 and toward BA8, 9, 10, and 46. Further, these fibers traverse from the depths of BA40, 2, 3, 1, and 6 as they progress. SLF-2 also projects fibers from the supramarginal gyrus in the left hemisphere. SLF-3 lies between the supramarginal gyrus and the inferior frontal lobe in both the right and left hemispheres. CONCLUSIONS: The visual descriptions of the dissections were enriched after using Photoshop to avoid monotony. Increasing the visual quality with Photoshop features enable us to gain a better understanding of these pathways. Additionally, it facilitates the comprehension of the symptoms associated with pathology. We hope these results will further aid in reducing the occurrence of postoperative complications.

Dentate Nucleus: Connectivity-Based Anatomic Parcellation Based on Superior Cerebellar Peduncle Projections.

OBJECTIVE: Projections from the dentate nucleus (DN) follow a certain organized course to upper levels. Crossing and noncrossing fibers of the dentatorubrothalamic (DRT) tract terminate in the red nucleus and thalamus and have various connections throughout the cerebral cortex. We aimed to establish the microsurgical anatomy of the DN in relation to its efferent connections to complement the increased recognition of its surgical importance and also to provide an insight into the network-associated symptoms related to lesions and microsurgery in and around the region. METHODS: The cerebellum, DN, and superior cerebellar peduncle (SCP) en route to red nucleus were examined through fiber dissections from the anterior, posterior, and lateral sides to define the connections of the DN and its relationships with adjacent neural structures. RESULTS: The DN was anatomically divided into 4 areas based on its relation to the SCP; the lateral major, lateral anterosuperior, posteromedial, and anteromedial compartments. Most of the fibers originating from the lateral compartments were involved in the decussation of the SCP. The ventral fibers originating from the lateral anterosuperior compartment were exclusively involved in the decussation. The fibers from the posteromedial compartment ascended ipsilaterally and decussated, whereas most anteromedial fibers ascended ipsilaterally and did not participate in the decussation. CONCLUSIONS: Clarifying the anatomofunctional organization of the DN in relation to the SCP could improve microneurosurgical results by reducing the complication rates during infratentorial surgery in and around the nucleus. The proposed compartmentalization would be a major step forward in this effort.

Observational Case Analysis of Neonates With Large Cephalohematoma.

Introduction Cephalohematomas in the newborn period are related to the accumulation of blood between the bone and periosteum as a result of a series of adverse conditions during labor. The optimal approach to cephalohematoma cases is still unclear. In this study, we aimed to present the follow-up data of 94 newborns with a cephalohematoma size of >50 mm and a higher risk of ossification.  Methods  This is a single-center, non-randomized, prospective, observational study conducted from May 2014 to May 2019. Records of all newborns with cephalohematoma were reviewed in terms of gender, birth weight, cephalohematoma region, transverse/vertical diameter of the lesion, delivery method, and rate of ossification.  Results The girl-to-boy ratio was 53/41, with a mean gestational age of 38.3±1.4 weeks and a mean birth weight of 3,300±800 grams. The mean transverse/vertical diameter of cephalohematoma was 59±9 mm. Cephalohematoma was completely resorbed at the first-month control visits in 72 (76.6%) cases, whereas nine (9.57%) had an ossified cephalohematoma. The ossification was completely or partially resorbed in these at the end of the one-year follow-up.  Conclusion Hence, we suggest that an early intervention is not required in the routine treatment of cases with hematomas with a size of >50 mm in size unless otherwise stipulated with clinical indications.

Minimally Invasive Approach Toward Percutaneous Direct Pars Repair: An Observational Study.

BACKGROUND: Spondylolysis refers to a defect of the vertebral pars interarticularis. Percutaneous direct pars repair using a minimally invasive technique was performed in a group of young patients to maintain their spinal segment movement and to restore their normal anatomy. The aim of this study was to present the clinical, functional, and radiologic outcomes of pars defects that were repaired percutaneously via the minimally invasive technique. METHODS: This was a single-center, nonrandomized, prospective study of the demographic, clinical, functional, and radiographic outcomes of 18 patients (age range, 18-32 years). The visual analog scale for back pain and the Oswestry Disability Index were used to evaluate the functional outcomes. The Macnab criteria were applied to evaluate patient satisfaction after surgery. RESULTS: All patients were admitted with bilateral pars fracture at the level of L4 (n = 4) or L5 (n = 14). The average duration of clinical follow-up was 16.04 months (range, 12-28 months). With reference to the Macnab criteria, 17 patients (94%) showed perfect or good outcomes. Fusion or bridging of bones was observed on computed tomography in 14 patients (77%) at the last radiological examination. CONCLUSIONS: Minimally invasive surgery to treat symptomatic spondylolysis is a safe option that minimizes muscle and soft tissue dissection. In this study, good clinical and functional outcomes were achieved in young patients with low complications and high fusion rates using completely percutaneous treatment.

Endoscopic Untethering of Tight Filum Terminale: An Operative Technique.

AIM: To demonstrate the various technical advantages of minimally invasive endoscopic untethering of tight filum terminale for the treatment of tethered cord syndrome (TCS). MATERIAL AND METHODS: In five pediatric cases of TCS, we performed untethering by using the endoscopic technique. The age of the patients were 6, 7, 8, 9, and 12 years old. We used a nasal speculum of the transsphenoidal approach during the endoscopic surgical procedure. RESULTS: All the procedures were performed uneventfully, except for one case with a split cord malformation that showed neurologic deterioration caused by excision of the diastematomyelic fibrous septum at the thoracic level (unrelated to the endoscopic procedure at the L5-S1 level). This patient was referred to a rehabilitation clinic 5 days after surgery and showed significant improvement by the third postoperative month. The other four patients were discharged 1 day after the operation. CONCLUSION: Endoscopic release of filum terminale is a safe technique especially if it is performed with neuromonitoring. This technique may shorten the length of hospital stay and reduce perioperative blood loss. However, futher studies with a larger number of patients and long-term follow-up are needed.

Comparison of Two Minimally Invasive Techniques with Endoscopy and Microscopy for Extraforaminal Disc Herniations.

OBJECTIVE: Extraforaminal disc herniations are extraordinary herniations because they are located outside the foraminal bony borders and compress the root exiting at the corresponding level, whereas in median or paramedian herniations, the root 1 level below is compressed. Percutaneous endoscopic discectomy (PED) and microscopic extraforaminal discectomy (MEFD) are 2 popular contemporary techniques that have been performed extensively for these herniations since the 1970s. METHODS: In this study, we retrospectively analyzed 118 patients who underwent either PED (66 patients) or MEFD (52 patients). All the patients were clinically evaluated for neurologic examination findings, visual analog scale (VAS) scores for leg pain and Oswestry Disability Index (ODI) preoperatively and on the seventh postoperative day as well as 6 and 12 months after surgery. The complication rates and types of both techniques were discussed. RESULTS: The preoperative VAS score and ODI were all comparable. Improvements in VAS scores 6 months postoperatively and improvements in ODI at all follow-up periods were statistically significant in favor of PED. However, there was great discrepancy regarding the postsurgical complications in favor of MEFD. CONCLUSIONS: PED is more prone to complications because this technique is strictly dependent on the tubular system and the ideal anatomy of the Kambin triangle. Variations in or degeneration of the Kambin triangle can lead to devastating complications in the PED technique, but normal anatomic conditions are feasible in only approximately 20% of patients. The most important feature of this study was that both techniques were performed by the same experienced team, who developed their own concept.

Effect of perioperative aspirin use on hemorrhagic complications in elective craniotomy for brain tumors: results of a single-center, retrospective cohort study.

OBJECTIVE: In daily practice, neurosurgeons face increasing numbers of patients using aspirin (acetylsalicylic acid, ASA). While many of these patients discontinue ASA 7-10 days prior to elective intracranial surgery, there are limited data to support whether or not perioperative ASA use heightens the risk of hemorrhagic complications. In this study the authors retrospectively evaluated the safety of perioperative ASA use in patients undergoing craniotomy for brain tumors in the largest elective cranial surgery cohort reported to date. METHODS: The authors retrospectively analyzed the medical records of 1291 patients who underwent elective intracranial tumor surgery by a single surgeon from 2007 to 2017. The patients were divided into three groups based on their perioperative ASA status: 1) group 1, no ASA; 2) group 2, stopped ASA (low cardiovascular risk); and 3) group 3, continued ASA (high cardiovascular risk). Data collected included demographic information, perioperative ASA status, tumor characteristics, extent of resection (EOR), operative blood loss, any hemorrhagic and thromboembolic complications, and any other complications. RESULTS: A total of 1291 patients underwent 1346 operations. The no-ASA group included 1068 patients (1112 operations), the stopped-ASA group had 104 patients (108 operations), and the continued-ASA group had 119 patients (126 operations). The no-ASA patients were significantly younger (mean age 53.3 years) than those in the stopped- and continued-ASA groups (mean 64.8 and 64.0 years, respectively; p < 0.001). Sex distribution was similar across all groups (p = 0.272). Tumor locations and pathologies were also similar across the groups, except for deep tumors and schwannomas that were relatively less frequent in the continued-ASA group. There were no differences in the EOR between groups. Operative blood loss was not significantly different between the stopped- (186 ml) and continued- (220 ml) ASA groups (p = 0.183). Most importantly, neither hemorrhagic (0.6%, 0.9%, and 0.8%, respectively; p = 0.921) nor thromboembolic (1.3%, 1.9%, and 0.8%; p = 0.779) complication rates were significantly different between the groups, respectively. In addition, the multivariate model revealed no statistically significant predictor of hemorrhagic complications, whereas male sex (odds ratio [OR] 5.9, 95% confidence interval [CI] 1.7-20.5, p = 0.005) and deep-extraaxial-benign ("skull base") tumors (OR 3.6, 95% CI 1.3-9.7, p = 0.011) were found to be independent predictors of thromboembolic complications. CONCLUSIONS: In this cohort, perioperative ASA use was not associated with the increased rate of hemorrhagic complications following intracranial tumor surgery. In patients at high cardiovascular risk, ASA can safely be continued during elective brain tumor surgery to prevent potential life-threatening thromboembolic complications. Randomized clinical trials with larger sample sizes are warranted to achieve a greater statistical power.

Microsurgical Gross Total Resection of a WHO Grade II Cerebellopontine Angle Ependymoma in an Adult.

Infratentorial ependymomas that arise in the fourth ventricle and extend into the cerebellopontine angle (CPA) through the foramina of Luschka are well described. However, a primary CPA location of an ependymoma is distinctly uncommon. In this video, we present a 46-year-old man with episodes of dizziness, left-sided tinnitus, imbalance, double vision, and nausea. An magnetic resonance imaging (MRI) scan of the head showed a large mass lesion centered in the CPA with heterogenous enhancement. Differential diagnosis included ependymoma, meningioma, schwannoma of the vestibular nerve, or lower cranial nerves, and choroid plexus papilloma. He underwent microsurgical gross total resection of the tumor via a retrosigmoid approach. Direct stimulation of the cranial nerves was performed throughout the case and there was no attachment of the tumor to any cranial nerve to suggest that this might be a schwannoma. The tumor encased important vasculature, including the posterior-inferior cerebellar artery. The histopathology was a grade II ependymoma. The patient tolerated the surgery well and his postoperative course was uneventful. He remained neurologically intact. He received radiation therapy and there was no recurrent or residual disease on follow-up studies. This video demonstrates important steps of the surgical approach and microsurgical resection techniques for this type of challenging tumor. The link to the video can be found at: https://youtu.be/KK-y6EYh888 .

Surgical outcomes of decompressive laminectomy by transspinous approach for degenerative lumbar spinal stenosis.

OBJECTIVE: To assess clinical and radiographical outcomes of transspinous decompression technique for the treatment of degenerative central lumbar spinal stenosis. METHODS: The single-centre, non-randomised interventional, prospective, observational study was conducted Neurosurgery Clinic of Mazhar Osman Research and Training Hospital for Psychiatry and Neurology, Istanbul, Turkey from May 2013 and May 2016 and comprised adult patients with refractory symptoms from degenerative central lumbar spinal stenosis who underwent lumbar spinous processsplitting laminectomy. Pre- and post-operative Oswestry Disability Index score, visual analogue scale for overall pain, maximum walking distance and anteroposterior diameter of the spinal canal on magnetic resonance imaging were assessed on follow up examination. SPSS 22 was used for data analysis. RESULTS: Of the 89 patients, 7(7.86%) were lost to follow-up, while 82(92.14%) completed the study. Of them, 42(51%) were women and 40(49%) were men. Overall mean age was 63.86±10.02 years (range: 40-85 years). A total of 95 transspinous decompressive laminectomies were performed. Mean number of decompressed spinal segments was 1.16. Median duration of surgical procedure was 45 min, while mean length of hospital stay was 1.22±0.47 days. Mean decrease in pre operative Oswestry Disability Index scoreat 1-year was 56.4% and overall visual analogue scale was 55.9%.Mean increase of 155.2% was documented over pre-operative maximum walking distance. Radiological assessment revealed a 40.7% increase in the mean and anteroposteriordiameter of the spinal canal at the level of the target lesion. The improvement in various parameters was statistically significant (p<0.001).. CONCLUSIONS: Lumbar spinous process-splitting laminectomy led to significant improvement with respect to patient-reported perceived recovery, functional disability and radiological evidence of effective surgical decompression in patients with lumbar spinal stenosis..

Frontal lobe intracerebral schwannoma mimicking metastatic lesion in a patient with papillary thyroid carcinoma.

Intracerebral schwannomas are quite rare. Due to their rarity and lack of pathognomonic imaging features, intracerebral schwannoma may be overlooked in the initial differential diagnosis of an intra-axial mass with heterogeneous ring enhancement, such as a high-grade glioma, metastasis or lymphoma. Here, we present a 21-year-old woman with prior diagnosis of papillary thyroid carcinoma and recent history of seizures who had a heterogeneously ring-enhancing left frontal lobe mass. Our presumptive diagnosis was a metastatic tumor since she had a history of thyroid cancer. Because of uncertainty in preoperative differential diagnosis, the decision was made to proceed with excisional biopsy of the tumor via craniotomy. She underwent uneventful gross total resection of the tumor that histopathology revealed as an intracerebral schwannoma.

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.

Gross Total Resection of Chordoid Glioma of the Third Ventricle via Anterior Interhemispheric Transcallosal Transforaminal Approach at Two Stages.

Suprasellar tumors in particular tumors located in the retrochiasmatic area and anterior third ventricle are challenging cases in terms of optimal surgical exposure. Several approaches have been described including transsylvian, translamina terminalis, endoscopic endonasal, and anterior interhemispheric. Each approach has advantages and disadvantages. In this video, we present a case of retrochiasmatic anterior third ventricular tumor that was operated via anterior interhemispheric transcallosal transforaminal approach. The patient is a 42-year-old female who presented with sudden onset of severe headache and depressed level of consciousness. Computed tomography (CT) scan of the head showed a hemorrhage in the third ventricle and suprasellar cisterns. CT angiogram and magnetic resonance imaging (MRI) confirmed diagnosis of hemorrhagic mass lesion in the third ventricle. Upon further questioning of her family, we found out that she was having excessive urination and short-term memory problems for last 2 weeks. First, ventriculostomy was placed for obstructive hydrocephalus. She then underwent surgical resection via anterior interhemispheric transcallosal transforaminal approach. Foramen of Monro was enlarged by performing transchoroidal dissection. Using transforaminal route, tumor was resected. Due to the narrow surgical corridor and high vascularity of the tumor, decision was made to come back at a second stage. Using same surgical approach, in the second stage, gross total resection was performed. Postoperative MRI confirmed gross total resection. Histopathology was chordoid glioma of the third ventricle. She made excellent recovery with persistent diabetes insipidus. Currently, she is completing radiation therapy. In this video, we demonstrate techniques and pitfalls of anterior interhemispheric transcallosal approach to anterior third ventricular tumor. The link to the video can be found at: https://youtu.be/CI5c6Zup8sY .

Microsurgical Resection of Tuberculum Sellae Meningioma via Pterional Craniotomy with Extradural Anterior Clinoidectomy and Optic Unroofing.

Microsurgical treatment of suprasellar tumors, in particular tuberculum sellae meningiomas, poses significant challenge. These tumors are surrounded by vital neurovascular structures, such as optic apparatus, pituitary stalk, internal carotid artery and its branches, and anterior cerebral arteries. In large and complex cases, early identification and decompression of these structures may facilitate safer dissection and resection. Therefore, extradural anterior clinoidectomy with optic unroofing facilitates the internal carotid artery exposure and optic nerve decompression. In this video, we describe a 37-year-old female patient who presented with new onset of severe headaches. On visual examination, she was found to have bitemporal visual defects. MRI scan of the head showed a large, approximately 3 cm suprasellar tumor consistent with tuberculum sellae meningioma. She underwent surgical resection via pterional craniotomy with extradural anterior clinoidectomy and optic unroofing. Microsurgical gross total resection was achieved and histopathology was WHO grade II meningioma. She had an uneventful postoperative course and visual field examination improved significantly. In this video, surgical technique in performing extradural anterior clinoidectomy and optic unroofing and steps of microsurgical resection are demonstrated. The link to the video can be found at: https://youtu.be/oPZ8NTyvxJc .

Hypertrophic Olivary Degeneration: Neurosurgical Perspective and Literature Review.

BACKGROUND: Hypertrophic olivary degeneration (HOD) occurs because of posterior fossa or brainstem lesions that disrupt the dentato-rubro-olivary tract, well known as the Guillain-Mollaret triangle. Clinical and radiologic hallmarks of this condition are palatal myoclonus and T2 hyperintensity of the inferior olivary complex on magnetic resonance imaging (MRI), respectively. Because symptomatic HOD can complicate the recovery of patients with posterior fossa or brainstem lesions, the purpose of this study is to evaluate clinical and imaging findings of patients with HOD. METHODS: Sixteen patients (8 female and 8 male) with a mean age of 40.7 years, (range, 5-83 years) years were included in this study based on clinical symptoms and MRI findings. RESULTS: We reviewed the clinical and imaging findings in 16 cases of HOD at our institution. Seven patients (43.7%) had posterior fossa tumors, 6 patients (37.5%) had cavernoma, 2 patients (12.5%) sustained traumatic brain injury, and only 1 patient (6.2%) had cerebellar infarction. Posterior fossa surgery was performed in 13 (81.2%) of these patients. HOD was detected a mean of 7.2 months (range, 0.5-18 months) after surgery or primary neurologic insult. Unilateral HOD was observed in 10 patients (62.5%), while bilateral HOD was observed in only 6 patients (37.5%). Seven patients (43.7%) were asymptomatic for HOD, whereas 5 patients (31.2%) had symptoms attributable to HOD. Two patients died because of primary tumors, although mean follow-up after detection of HOD on MRI was 52.2 months (range, 1-120 months) in the remaining 14 patients. In these cases, no change in clinical symptoms or imaging findings was detected during follow-up. CONCLUSIONS: In this series, posterior fossa tumors and cavernomas were the most common causes of HOD. Although most of the patients with HOD remained asymptomatic, HOD complicated the course of recovery in almost one quarter of the patients included in this study. Neurosurgeons should be aware of HOD, which has characteristic clinical and imaging findings. In addition, HOD can complicate the recovery of patients with disruption to the dentato-rubro-olivary tract.