Open Surgical Approaches for Meningiomas.

Meningiomas are the most common intracranial extra-axial primary tumor. Although most are low grade and slow growing, resection can be technically challenging, particularly when located at the skull base. Appropriate craniotomy and approach selection are of paramount importance to minimize brain retraction, optimize exposure, and achieve complete resection. This article summarizes various craniotomies and their approaches to meningiomas, and illustrates some nuances in performing these techniques with cadaveric dissection and operative videos.

Vidian Canal as a Transcranial Landmark: Anatomy, Technique, and Illustrative Cases.

Objective The vidian nerve can be accessed in transcranial approaches in carefully selected patients to ensure its preservation and to serve as a landmark for sphenoid sinus entry. This report is to review a technique, evaluate it in laboratory settings, and present two illustrative cases. Design The study involves cadaveric dissection and illustrative cases. Setting The study conducted in a cadaveric dissection laboratory. Participants The object of the study is one cadaveric head and two illustrative clinical cases. Main Outcome Measures Two cases using this approach were illustrated, and a cadaver dissection was performed in a step-by-step fashion. Results: The vidian canal can be accessed by drilling the anterolateral triangle. Two illustrated cases were presented; in one, the vidian nerve was used as part of a corridor to access the sphenoid sinus for tumor delivery, and in the other, the technique was used to find and preserve the vidian nerve during transcranial resection. Conclusion Careful identification of the vidian canal in transcranial surgery is a beneficial technique in carefully selected cases which allows identification of the nerve both for its preservation in selected cases and to create the vidian-maxillary corridor for tumor resection. Knowing the anatomy and pneumatization variants is important in the surgical approach.

Polymorphous low-grade neuroepithelial tumor of the young: Rare tumor and review of the literature.

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described low-grade neuroepithelial tumor with an infiltrative growth pattern and oligodendrocyte-like cells that are CD34 immunopositive. Correlating histology and results from molecular testing is critical to correctly diagnosing PLNTY, as its histologic appearance is similar to oligodendrogliomas and shares genetic abnormalities common to other low-grade epilepsy associated tumors (LEATs). In this case report, we describe a 31-year-old female with intractable epilepsy found to have a temporal mass and diagnosed with PLNTY after histopathologic and molecular testing. We describe the radiographic, histologic, and genetic features in relation to the epileptic and oncologic outcomes for this patient. Then, we compare these features and outcomes to other cases of PLNTY described in the literature.

Anatomy and White Matter Connections of the Superior Parietal Lobule.

BACKGROUND: The superior parietal lobule (SPL) is involved in somatosensory and visuospatial integration with additional roles in attention, written language, and working memory. A detailed understanding of the exact location and nature of associated white matter tracts could improve surgical decisions and subsequent postoperative morbidity related to surgery in and around this gyrus. OBJECTIVE: To characterize the fiber tracts of the SPL based on relationships to other well-known neuroanatomic structures through diffusion spectrum imaging (DSI)-based fiber tracking validated by gross anatomical dissection as ground truth. METHODS: Neuroimaging data of 10 healthy, adult control subjects was obtained from a publicly accessible database published in Human Connectome Project for subsequent tractographic analyses. White matter tracts were mapped between both cerebral hemispheres, and a lateralization index was calculated based on resultant tract volumes. Post-mortem dissections of 10 cadavers identified the location of major tracts and validated our tractography results based on qualitative visual agreement. RESULTS: We identified 9 major connections of the SPL: U-fiber, superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, middle longitudinal fasciculus, extreme capsule, vertical occipital fasciculus, cingulum, and corpus callosum. There was no significant fiber lateralization detected. CONCLUSION: The SPL is an important region implicated in a variety of tasks involving visuomotor and visuospatial integration. Improved understanding of the fiber bundle anatomy elucidated in this study can provide invaluable information for surgical treatment decisions related to this region.

Anatomy and White Matter Connections of the Lingual Gyrus and Cuneus.

BACKGROUND: The medial occipital lobe, composed of the lingual gyrus and cuneus, is necessary for both basic and higher level visual processing. It is also known to facilitate cross-modal, nonvisual functions, such as linguistic processing and verbal memory, after the loss of the visual senses. A detailed cortical model elucidating the white matter connectivity associated with this area could improve our understanding of the interacting brain networks that underlie complex human processes and postoperative outcomes related to vision and language. METHODS: Generalized q-sampling imaging tractography, validated by gross anatomic dissection for qualitative visual agreement, was performed on 10 healthy adult controls obtained from the Human Connectome Project. RESULTS: Major white matter connections were identified by tractography and validated by gross dissection, which connected the medial occipital lobe with itself and the adjacent cortices, especially the temporal lobe. The short- and long-range connections identified consisted mainly of U-shaped association fibers, intracuneal fibers, and inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, middle longitudinal fasciculus, and lingual-fusiform connections. CONCLUSIONS: The medial occipital lobe is an extremely interconnected system, supporting its ability to perform coordinated basic visual processing, but also serves as a center for many long-range association fibers, supporting its importance in nonvisual functions, such as language and memory. The presented data represent clinically actionable anatomic information that can be used in multimodal navigation of white matter lesions in the medial occipital lobe to prevent neurologic deficits and improve patients' quality of life after cerebral surgery.

Anatomy and White Matter Connections of the Middle Frontal Gyrus.

BACKGROUND: The middle frontal gyrus (MFG) is involved in attention, working memory, and language-related processing. A detailed understanding of the subcortical white matter tracts connected within the MFG can facilitate improved navigation of white matter lesions in and around this gyrus and explain the postoperative morbidity after surgery. We aimed to characterize the fiber tracts within the MFG according to their connection to neuroanatomic structures through the use of diffusion spectrum imaging-based fiber tractography and validate the findings by gross anatomic dissection for qualitative visual agreement. METHODS: Tractography analysis was completed using diffusion imaging data from 10 healthy, adult subjects enrolled in the Human Connectome Project. We assessed the MFG as a whole component according to its fiber connectivity with other neural regions. Mapping was completed on all tracts within both hemispheres, with the resultant tract volumes used to calculate a lateralization index. A modified Klingler technique was used on 10 postmortem dissections to demonstrate the location and orientation of the major tracts. RESULTS: Two major connections of the MFG were identified: the superior longitudinal fasciculus, which connects the MFG to parts of the inferior parietal lobule, posterior temporal lobe, and lateral occipital cortex; and the inferior fronto-occipital fasciculus, which connected the MFG to the lingual gyrus and cuneus. Intra- and intergyral short association, U-shaped fibers were also identified. CONCLUSIONS: Subcortical white matter pathways integrated within the MFG include the superior longitudinal fasciculus and inferior fronto-occipital fasciculus. The MFG is implicated in a variety of tasks involving attention and memory, making it an important cortical region. The postoperative neurologic outcomes related to surgery in and around the MFG could be clarified in the context of the anatomy of the fiber bundles highlighted in the present study.

Anatomy and white matter connections of the fusiform gyrus.

The fusiform gyrus is understood to be involved in the processing of high-order visual information, particularly related to faces, bodies, and stimuli characterized by high spatial frequencies. A detailed understanding of the exact location and nature of associated white-tracts could significantly improve post-operative morbidity related to declining capacity. Through generalized q-sampling imaging (GQI) validated by gross dissection as a direct anatomical method of identifying white matter tracts, we have characterized these connections based on relationships to other well-known structures. We created the white matter tracts using GQI and confirmed the tracts using gross dissection. These dissections demonstrated connections to the occipital lobe from the fusiform gyrus along with longer association fibers that course through this gyrus. The fusiform gyrus is an important region implicated in such tasks as the visual processing of human faces and bodies, as well as the perception of stimuli with high spatial frequencies. Post-surgical outcomes related to this region may be better understood in the context of the fiber-bundle anatomy highlighted by this study.

Laser Interstitial Thermal Therapy Case Series: Choosing the Correct Number of Fibers Depending on Lesion Size.

BACKGROUND: Laser interstitial thermal therapy (LITT) is being used for the treatment of recurrent glioblastoma multiforme (GBM). Lesions can be treated using 1 or multiple LITT fibers depending on the preference of surgeons. Usually, more fibers are needed for coverage of larger tumors. OBJECTIVE: To investigate and analyze how tumor size affected the number of LITT fibers used. METHODS: This is a retrospective review of patients undergoing treatment of recurrent GBM. Patients were treated with up to 4 LITT fibers for adequate tumor coverage. Patient demographics, tumor characteristics, length of stay, complications, and biopsy results were recorded. RESULTS: A total of 43 cases were treated using LITT, and of these cases, 31 consisted of contiguous lesions. We used more fibers to treat larger tumor volumes. On average, for each 5 cc of tumor volume, a fiber was added for proper coverage (P = .554). Complications and length of stay were similar across the groups (P = .378, P = .941). CONCLUSION: LITT can be used for the treatment of recurrent GBM. For each 5 cc of tumor volume, a LITT fiber can be added to the treatment plan.

Surgical Treatment of Tethered Cord Syndrome in Adults: A Systematic Review and Meta-Analysis.

OBJECTIVE: In the healthy spine, the spinal cord moves unimpeded with spinal fluid pulsation in the rostral and caudal directions. When a portion of the spinal cord becomes attached to lesions within the spinal column, excess strain can cause signs and symptoms such as pain, motor deficits, sensory deficits, bladder dysfunction, and bowel dysfunction. This condition is termed tethered cord syndrome. There are no clear guidelines for offering surgical intervention, although there is a general consensus that worsening signs and symptoms increase the likelihood that patients will need surgery. METHODS: In this article, we conduct a systematic review and meta-analysis for all available literature within the Ovid (MEDLINE), PubMed, and Google Scholar databases to evaluate common symptoms among patients with tethered cord and to examine how surgery affects symptoms. RESULTS: Within the cohort of 730 patients, 708 (97%) were treated surgically by a detethering procedure. The most common preoperative sign or symptom was pain (81%), followed by motor deficits (63%), sensory deficits (61%), bladder dysfunction (56%), and bowel dysfunction (15%). One percent of patients had no deficit or symptom. Pain was the symptom that was most responsive to surgery, with 81% of patients reporting that their pain improved after detethering. CONCLUSIONS: Tethered cord syndrome should be included in the differential diagnosis in patients presenting with back or leg pain, somatosensory symptoms of the lower extremities, muscular weakness, urodynamic dysfunction, or bowel dysfunction. After a definitive diagnosis is made, patients should be counseled about surgical detethering as an option.

Laser Interstitial Thermal Therapy for Metastatic Melanoma After Failed Radiation Therapy: A Case Series.

BACKGROUND: Laser interstitial thermal therapy (LITT) is a growing technology to treat a variety of brain lesions. It offers an alternative to treatment options, such as open craniotomy and stereotactic radiosurgery. OBJECTIVE: To analyze our experience using LITT for metastatic melanoma. METHODS: This is a retrospective chart review of the patients from our institution. Our case series involves 5 patients who had previously failed radiation treatment. RESULTS: Our patients have low complication rates and short hospital stays. Both are considerably lower when compared to the literature for metastatic melanoma. CONCLUSION: LITT is a safe therapy, with few complications and short hospital stays.

Neurochemical supplementation in patients with depressed levels of participation after brain tumor surgery: Rationale and preliminary results.

A unique challenge in some brain tumor patients is the fact that tumors arising in certain areas of the brain involve the neural structures of consciousness or alertness, limiting the patient's ability to participate in rehabilitation following surgery. A critical question is whether neurostimulant therapy can help patients participate in rehabilitation efforts. We performed a retrospective review of all patients undergoing brain tumor surgery by the senior author from 2012 to 2018. We limited this study to patients with tumors occupying critical structures related to consciousness, alertness, and motor initiation. A combination of methylphenidate and levodopa/carbidopa was used to monitor the progress of patients through neurorehabilitation efforts. We identified 101 patients who experienced an inability to participate in rehabilitation (ITPR) in the post-operative period. Of these, 86 patients (85%) were treated with methylphenidate and levodopa/carbidopa. Cases of ITPR were related to dysfunction of the brainstem (12/86 cases, 14%), thalamus (17/86 cases, 20%), hypothalamus (14/86 cases, 16%), basal ganglia (13/86 cases, 15%), and medial frontal lobe (30/86 cases, 35%). Of the 86 individuals treated, 47/86 patients (55%) showed early improvement in their ability to participate with rehabilitation. At three month follow-up, 58/86 patients (67%) had returned to living independently or were at least interactive and cooperative during follow-up examination. This feasibility report suggests that combined therapy with methylphenidate and levodopa/carbidopa may help patients participate in neurorehabilitation efforts in the immediate post-operative period following brain tumor surgery. Randomized, controlled clinical trials are needed to explore this concept more thoroughly.

Anatomy and white matter connections of the lateral occipital cortex.

PURPOSE: White matter tracts link different regions of the brain, and the known functions of those interconnected regions may offer clues about the roles that white matter tracts play in information relay. The authors of this report discuss the structure and function of the lateral occipital lobe and how the lateral occipital lobe communicates with other regions via white matter tracts. METHODS: The authors used generalized q-sampling imaging and cadaveric brain dissections to uncover the subcortical white matter connections of the lateral occipital lobe. The authors created GQI of ten healthy controls and dissected ten cadaveric brains. RESULTS: The middle longitudinal fasciculus, vertical occipital fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, optic radiations, and a diverse array of U-shaped fibers connect the lateral occipital lobe to itself, parts of the temporal, parietal, and medial occipital cortices. The complex functional processes attributed to the lateral occipital lobe, including object recognition, facial recognition, and motion perception are likely related to the subcortical white matter tracts described within this study. CONCLUSIONS: There was good concordance between the white matter tracts generated using GQI and the white matter tracts that were found after dissection of the cadaveric brains. This article presents the anatomic connections of the lateral occipital lobe and discusses the associated functions.

Anatomy and White Matter Connections of the Superior Frontal Gyrus.

The superior frontal gyrus (SFG) is an important region implicated in a variety of tasks including motor movement, working memory, resting-state, and cognitive control. A detailed understanding of the subcortical white matter of the SFG could improve postoperative morbidity related to surgery around this gyrus. Through DSI-based fiber tractography validated by gross anatomical dissection, we characterized the fiber tracts of the SFG based on their relationships to other well-known neuroanatomic structures. Diffusion imaging from the Human Connectome Project from 10 healthy adult subjects was used for fiber tractography. We evaluated the SFG as a whole based on its connectivity with other regions. All tracts were mapped in both hemispheres, and a lateralization index was calculated based on resultant tract volumes. Ten cadaveric dissections were then performed using a modified Klingler technique to delineate the location of major tracts integrated within the SFG. We identified four major SFG connections: the frontal aslant tract connecting to the inferior frontal gyrus; the inferior fronto-occipital fasciculus connecting to the cuneus, lingual gyrus, and superior parietal lobule; the cingulum connecting to the precuneus and parahippocampal gyrus/uncus; and a callosal fiber bundle connecting the SFG bilaterally. The functional networks of the SFG involve a complex series of white matter tracts integrated within the gyrus, including the FAT, IFOF, cingulum, and callosal fibers. Postsurgical outcomes related to this region may be better understood in the context of the fiber-bundle anatomy highlighted in this study. Clin. Anat. 33:823-832, 2020. © 2019 Wiley Periodicals, Inc.

Anterior cervical discectomy and fusion requiring resection of the superior horn of thyroid cartilage: case report.

Anterior cervical discectomy and fusion (ACDF) is the most common surgical procedure utilized for degenerative diseases of the cervical spine. The authors present the case of a 64-year-old man who underwent an ACDF for degenerative changes causing cervical stenosis with myelopathy. The patient's symptoms consisted of pain and weakness of the bilateral upper extremities that slowly progressed over 1.5 years. During the procedure, the superior horn of the thyroid cartilage impeded proper retraction, preventing adequate visualization due to its prominent size. At this point, otorhinolaryngology was consulted, which allowed for safe resection of this portion of the thyroid cartilage while preserving nearby critical structures. With the frequent usage of this surgical approach for various etiologies, the importance of proper recognition and consultation is paramount. Encountering prominent thyroid cartilage resulting in surgical obstruction has not been described in the literature and this report represents a paradigm for the proper course of action.

Factors Associated with Treatment Failure and Radiosurgery-Related Edema in WHO Grade 1 and 2 Meningioma Patients Receiving Gamma Knife Radiosurgery.

BACKGROUND: Before the advent of radiosurgery, neurosurgical treatment of meningiomas typically involved gross total resection of the mass whenever surgery was deemed possible. Over the past 4 decades, though, Gamma Knife radiosurgery (GKRS) has proved to be an effective, minimally invasive means to control the growth of these tumors. However, the variables associated with treatment failure (regrowth or clinical progression) after GKRS and GKRS-related complications, such as cerebral edema, are less well understood. METHODS: We retrospectively collected data between 2009 and 2018 for patients who underwent GKRS for meningiomas. After data collection, we performed univariate and multivariable modeling of the factors that predict treatment failure and cerebral edema after GKRS. Hazard ratios (HR) and P values were determined for these variables. RESULTS: Fifty-two patients were included our analysis. The majority of patients were female (38/52,73%), and nearly all patients presented with a suspected or confirmed World Health Organization grade 1 meningioma (48/52, 92%). The median tumor volume was 3.49 cc (range, 0.22-20.11 cc). Evidence of meningioma progression after treatment developed in 5 patients (10%), with a median time to continued tumor growth of 5.9 months (range, 2.7-18.3 months). In multivariable analysis, patients in whom treatment failed were more likely to be male (HR = 8.42, P = 0.045) and to present with larger tumor volumes (HR = 1.27, P = 0.011). In addition, 5 patients (10%) experienced treatment-related cerebral edema. On univariate analysis, patients who experienced cerebral edema were more likely present with larger tumors (HR = 1.16, P = 0.028). CONCLUSIONS: Increasing meningioma size and male gender predispose to meningioma progression after treatment with GKRS. Increasing tumor size also predicts the development of postradiosurgery cerebral edema.

An Awake Contralateral, Transcallosal Approach for Deep-Seated Gliomas of the Basal Ganglia.

BACKGROUND: The basal ganglia and thalamus are uncommon locations for infiltrating gliomas. Tumors here are usually managed with biopsy and adjuvant therapy, with relatively poor results. Rarely do patients undergo extensive surgical intervention. It seems reasonable to suggest that successful cytoreduction may help these patients. However, this hypothesis has not been studied because of the general view that it is not possible to remove deep-seated brain tumors with acceptable outcomes. METHODS: Through retrospective data collection, we describe a small case series of patients undergoing awake contralateral, transcallosal surgery for deep-seated brain tumors affecting the basal ganglia. We describe our patient cohort, report on patient outcomes, and describe our surgical technique. RESULTS: Four patients underwent awake contralateral, transcallosal surgery for glioblastoma invading the basal ganglia. All 4 patients demonstrated hemibody weakness contralateral to the side of their tumors, with 3 patients confined to wheelchairs at presentation. Their ages ranged from 25 to 64 years. Tumor volumes ranged from 14 to 93 cm3. More than 50% resection of each tumor was achieved during surgery. In 2 cases, approximately 90% resection was achieved. Motor strength improved in 1 patient who presented with hemiplegia. Two patients required ventriculoperitoneal shunting for complications related to hydrocephalus. At the writing of this article, 2 of our patients were still alive, functional, and free of tumor progression. CONCLUSIONS: We present the results of our attempts to resect large gliomas infiltrating the basal ganglia in 4 patients. Our technique combined a contralateral, transcallosal approach with awake neuromonitoring. Our results suggest it is possible to remove these tumors with reasonable outcomes.