OBJECTIVE Chiari malformation Type I (CM-I) is a craniocervical junction disorder associated with descent of the cerebellar tonsils >5mm. The prevalence of CM-I is common, including 0.5-3.5% in the general population, 0.56-0.77% on MRI, and 0.62% in anatomical dissection studies. We sought to measure our surgical outcomes related to resolution/improvement of headaches, neurological outcomes, and syringomyelia compared with published adult CM-I studies from 2000-2019. METHODS From December 2003-June 2018, the first author performed 270° circumferential decompression on adult (>18y) CM-I patients. At admission and follow-up, all parameters were numerically evaluated; headaches were self-reported on the VAS scale, neurological condition was evaluated using Karnofsky Performance Score and European Myelopathy Score (EMS), and syrinx width (if present) was measured on MRI by Grades I-IV. All parameters were analyzed, compared, and statistically tested. We compared results to our previously published and updated systematic review of operative adult CM-I studies (studies from 2014-2019). RESULTS In our series, 121/118 (98%) experienced headache improvements and 100% experienced neurological improvements. Complete syrinx resolution was experienced by 35/43 (81%); 8 (19%) demonstrated significant improvement. In data from published studies (2000-2019), only 79% experienced headache resolution, 77% improvement of neurological status, and 74% resolution/improvement of syrinx (mean). CONCLUSION Our modified 270° circumferential microsurgical foramen magnum decompression for adult CM-I may be beneficial in improvement of outcomes, namely in resolutions of the syrinx, neurological symptoms, and headaches. We also confirm the association of BMI with CM-I. Further studies are needed to confirm our results.

In this video, we highlight the anatomy involved with microsurgical resection of a giant T11/T12 conus cauda equina schwannoma. Spinal schwannoma remains the third most common intradural spinal tumor. Tumors undergoing gross total resection usually do not recur. To our knowledge, this is the first video case report of giant cauda equina schwannoma resection. A 55-year-old female presented with paraparesis and urinary retention. Lumbar spine MRI revealed a contrast-enhancing intradural extramedullary tumor at the T11/T12 level. Surgery was performed in the prone position with intraoperative neurophysiology monitoring (somatosensory and motor evoked potentials—SSEPs and MEPs). T11/T12 laminectomies were performed. After opening the dura and arachnoid, the tumor was found covered with cauda equina nerve roots. We delineated the inferior pole of the tumor, followed by opening of the capsule and debulking the tumor. Subsequently, the cranial pole was dissected from the corresponding cauda equina nerve roots. Finally, the tumor nerve origin was identified and divided after nerve stimulation confirmed the tumor arose from a sensory nerve root. The tumor was removed; histological analysis revealed a schwannoma (WHO Grade I). Postoperative MRI revealed complete resection. The patient fully recovered her neurological function. This case highlights the importance of careful microsurgical technique and gross total resection of the tumor in the view of favorable postoperative neurological recovery of the patient. Intraoperative use of ultrasound is helpful to delineate preoperatively tumor extension and confirm postoperative tumor resection.

SUMMARY Astrocytoma is the second most common intramedullary tumor of predominantly low-grade malignancy in adult patients. Adult astrocytomas have better-quality prognosis compared with astrocytomas in children. Although a standardized surgical management protocol for spinal cord glioma is currently unavailable, surgery of low-grade astrocytoma should be aimed at gross total resection to preserve neurological function and to improve the outcome. Herein, we present a personal case series of four consecutive adult spinal cord astrocytoma patients who were operated on during the last few years. Tumor resection was performed in all patients utilizing microsurgical technique and intraoperative neurophysiologic monitoring. We also provide a literature review of the treatment of intramedullary astrocytoma in adults and discuss contemporary surgical management and prognosis.

BACKGROUND Posterior communicating (Pcom) aneurysms in the modern era have tended toward increased complexity and technical difficulties. The pretemporal approach is a valuable extension to the pterional approach for basilar apex aneurysms, but its advantages for Pcom aneurysms have not been previously elucidated. OBJECTIVE To quantify characteristics of the pretemporal approach to the Pcom. METHODS We dissected 6 cadaveric heads (12 sides) with a pretemporal transclinoidal approach and measured the following variables: (1) exposed length of internal carotid artery (ICA) proximal to the Pcom artery; (2) exposed circumference of ICA at the origin of Pcom; (3) deep working area between the optic nerve and tentorium/oculomotor nerve; (4) superficial working area; (5) exposure depth; and (6) the frontotemporal (superior posterolateral) and (7) orbito-sphenoidal (inferior anterolateral) angles of exposure. RESULTS Compared with pterional craniotomy, the pretemporal transclinoidal approach increased the exposed length of the proximal ICA from 3.3 to 11.7 mm (P = .0001) and its circumference from 5.1 to 7.8 mm (P = .0003), allowing a 210° view of the ICA (vs 137.9°). The deep and superficial working areas also significantly widened from 53.7 to 92.4 mm2 (P = .0048) and 252.8 to 418.2 mm2 (P = .0001), respectively; the depth of the exposure was equivalent. The frontotemporal and spheno-Sylvian angles increased by 17° (P = .0006) and 10° (P = .0037), respectively. CONCLUSION The pretemporal approach can be useful for complex Pcom aneurysms by providing easier proximal control, wider working space, improved aneurysm visualization, and more versatile clipping angles. Enhanced exposure results in a potentially higher rate of complete aneurysm obliteration and complication avoidance.

An amendment to this paper has been published and can be accessed via the original article.

ABSTRACT Objective Hemangioblastomas of the posterior cranial fossa and spinal cord in adults are excessively vascularized, well-differentiated, and scarce tumors with no metastatic potential. This paper discusses its surgical management and outcome, pointing out their morphological, radiological, and histopathological aspects. This report based on a personal series of six patients and on a literature review. Methods A single-institution personal 6-case series of adult patients diagnosed and operated on by a senior neurosurgeon (KIA) due to posterior cranial fossa or spinal cord hemangioblastoma was analyzed. For easier understanding of hemangioblastoma, we have classified them into four different types. Results The tumors, which were all surgically treated, were located in the posterior cranial fossa in five patients (4 cerebellar, 1 brain stem) and intramedullary in the thoracic spinal cord in one patient. All patients successfully recovered neurologically after a complete tumor resection, having no post-operative neurological deficit or other complications. Conclusion Surgical management of cerebellar and spinal cord hemangioblastoma in adults is highly dependent on its morphological features, as well as on microsurgical technique applied. Since huge differences exist between the cystic/nodular tumor type (Type 1) and the solid type and its two additional variants (Types 2–4), morphology is the most important consideration when deciding surgical approach. Despite significant morphological differences among different subtypes of hemangioblastomas, their histology appears to be relatively similar. Nonetheless, a meticulous and refined surgical technique has to be utilized to achieve a successful outcome.

Laboratory-based cadaveric training is essential for the development and refinement of neurosurgical technical skills in the operating room and has become an integral training component around the world. Postresidency fellowship—the first pillar of skull base surgery training—includes both hands-on clinical care and surgery supervised by an experienced skull base surgeon. Time is spent in a skull base laboratory practicing approaches and developing anatomic mastery. The second pillar includes formal skull-base courses—institutional dissection laboratories provide continuous anatomic and surgical education while complementary annual or semiannual cadaver courses gather recognized experts to share their knowledge and experience in an essential 2- to 3-day setting. In this paper, we present the history of the longest running annual skull-base cadaver microsurgical course, which was started by Dr. Ossama Al-Mefty: Annual Surgical Approaches to the Skull Base Course. At the Microscopic and Endoscopic Hands-on Cadaver Workshop, held in St. Louis, Missouri, we celebrated its 30th anniversary in April 2019. We also present the impact this course has had on neurosurgery and skull base surgery and on the professional and scientific developments of its participants in particular.

Anterior cervical discectomy and fusion (ACDF) is one of the most common spinal procedures, frequently used for the treatment of cervical spine degenerative diseases. It was first described in 1958. Interestingly, to our knowledge, 3-level ACDF has not been previously published as a peer-reviewed video case with a detailed description of intraoperative microsurgical anatomy. In this video, we present the case of a 33-year-old male who presented with a combination of myelopathy (hyperreflexia and long tract signs in the upper and lower extremities) and bilateral radiculopathy of the upper extremities. He had been previously treated conservatively with physical therapy and pain management for 6 months without success. We performed 3-level microsurgical ACDF from C4 to C7. All 3 levels were decompressed, and bone allografts were placed to achieve intervertebral body fusion. A titanium plate was utilized from C4 to C7 for internal fixation. The patient was discharged home on the first postoperative day. His pain, numbness and tingling resolved, as well as his myelopathy. No perioperative complications were encountered. Herein we present the surgical anatomy of our operative technique including certain technical tips. Written consent was obtained directly from the patient.

SUMMARY Myxopapillary ependymomas (MPE) of the spinal cord are slow-growing benign tumors most frequently found in adults between 30 and 50 years of age. They arise from the ependyma of the filum terminale and are located in the area of the medullary conus and cauda. The recommended treatment option is gross total resection, while patients undergoing subtotal resection usually require radiotherapy. Complete resection without capsular violation can be curative and is often accomplished by simple resection of the filum above and below the tumor mass. Nevertheless, dissemination and distant treatment failure may occur in approximately 30% of the cases. In this paper, we propose an original MPE classification, which is based upon our personal series report concerned with tumor location and its correlation with the extent of resection. We also provide literature review, discussing surgical technique, tumor recurrence rate and dissemination, and adjuvant treatment. In conclusion, our findings suggest that MPE management based on the proposed 5-type tumor classification is favorable when total surgical resection is performed in carefully selected patients. Yet, further studies on a much broader model is obligatory to confirm this.

Abstract Dumbbell schwannoma of the cervical spine is a known entity,1-5 and should be radically resected with the preservation or improvement of neurological function. However, to our knowledge, an operative video of a C1-C2 cervical dumbbell schwannoma with ventral extension and dorsal spinal cord compression has not been reported previously. This tumor resection video performed by the senior author (KIA) includes details of dural opening, and techniques for microsurgical resection and for postoperative closure to avoid cerebrospinal fluid (CSF) leak and pseudomeningocele formation. Fat grafting was performed through a small paraumbilical incision. The patient was prone in MAYFIELD 3-point pin fixation (Integra LifeSciences, Plainsboro Township, New Jersey). Intraoperative neurophysiological electrodes were placed for somatosensory evoked potential (SSEP) and motor evoked potential (MEP) monitoring. Stealth neuronavigation was used to aid in tumor localization. A small suboccipital craniectomy and C1 laminectomy were performed before opening the dura. Using a microsurgical technique, the dura was opened in the form of the letter “Y.” The right-sided dentate ligament was cut to aid in the mobilization of the tumor away from the spinal cord. After dividing the tumor at the dumbbell isthmus, the ventral tumor component was removed, with attention paid to the division of a perforator coming from the vertebral artery. Intraforaminal tumor debulking was performed with a cavitron ultrasonic surgical aspirator (CUSA) and resected. High cervical dumbbell schwannoma should be radically resected while preserving and improving preoperative neurological function. Avoidance of CSF leak and formation of pseudomeningocele should be planned at the beginning, utilizing fascia and fat graft to avoid this feared complication. The patient provided written consent and permission to publish her image.

Globally, the discipline of neurosurgery has evolved remarkably fast. Despite being one of the latest medical specialties, which appeared only around hundred years ago, it has witnessed innovations in the aspects of diagnostics methods, macro and micro surgical techniques, and treatment modalities. Unfortunately, this development is not evenly distributed between developed and developing countries. The same is the case with neurosurgical education and training, which developed from only traditional apprentice programs in the past to more structured, competence-based programs with various teaching methods being utilized, in recent times. A similar gap can be observed between developed and developing counties when it comes to neurosurgical education. Fortunately, most of the scholars working in this field do understand the coherent relationship between neurosurgical education and neurosurgical practice. In context to this understanding, a symposium was organized during the World Federation of Neurological Surgeons (WFNS) Special World Congress Beijing 2019. This symposium was the brain child of Prof. Yoko Kato—one of the eminent leaders in neurosurgery and an inspiration for female neurosurgeons. Invited speakers from different continents presented the stages of development of neurosurgical education in their respective countries. This paper summarizes the outcome of these presentations, with particular emphasis on and the challenges faced by developing countries in terms of neurosurgical education and strategies to cope with these challenges.

Background Neuroanatomists have long been fascinated by the complex topographic organization of the cerebrum. We examined historical and modern phylogenetic theories pertaining to microneurosurgical anatomy and intrinsic brain tumor development. Methods Literature and history related to the study of anatomy, evolution, and tumor predilection of the limbic and paralimbic regions were reviewed. We used vertebrate histological cross-sections, photographs from Albert Rhoton Jr.’s dissections, and original drawings to demonstrate the utility of evolutionary temporal causality in understanding anatomy. Results Phylogenetic neuroanatomy progressed from the substantial works of Alcmaeon, Herophilus, Galen, Vesalius, von Baer, Darwin, Felsenstein, Klingler, MacLean, and many others. We identified two major modern evolutionary theories: “triune brain” and topological phylogenetics. While the concept of “triune brain” is speculative and highly debated, it remains the most popular in the current neurosurgical literature. Phylogenetics inspired by mathematical topology utilizes computational, statistical, and embryological data to analyze the temporal transformations leading to three-dimensional topographic anatomy. These transformations have shaped well-defined surgical planes, which can be exploited by the neurosurgeon to access deep cerebral targets. The microsurgical anatomy of the cerebrum and the limbic system is redescribed by incorporating the dimension of temporal causality. Yasargil’s anatomical classification of glial tumors can be revisited in light of modern phylogenetic cortical categorization. Conclusion Historical and modern topological phylogenetic notions provide a deeper understanding of neurosurgical anatomy and approaches to the limbic and paralimbic regions. However, many questions remain unanswered and further research is needed to elucidate the anatomical pathology of intrinsic brain tumors.

On September 9-12, 2019, I traveled to Beijing, China for the World Congress of Neurosurgery. I was eager to attend the biggest event of my profession for two reasons. One was my nomination for second vice-president of the World Federation of Neurosurgical Societies (WFNS). The second reason was to learn about Chinese culture for the first time in my life. I was honored to be elected for an officer position of the WFNS and I tremendously enjoyed the grandiosity of the Great Wall of China (Figure 1), the Forbidden City, and Summer Palace; I also enjoyed trying authentic Chinese food.

No abstract available.