Advances in Cranial Surgery.

The landscape of the cranial neurosurgery has changed tremendously in past couple of decades. The main frontiers including introduction of neuro-endoscopy, minimally invasive skull base approaches, SRS, laser interstitial thermal therapy and use of tubular retractors have revolutionized the management of intracerebral hemorrhages, deep seated tumors other intracranial pathologies. Introduction of these novel techniques is based on smaller incisions with maximal operative corridors, decreased blood loss, shorter hospital stays, decreased post-operative pain and cosmetically appealing scars that improves patient satisfaction and clinical outcomes. The sophisticated tools like neuroendoscopy have improved light source, and better visualization around the corners. Advanced navigated tools and channel-based retractors help us to target deeply seated lesions with increased precision and minimal disruption of the surrounding neurovascular tissues. Advent of stereotactic radiosurgery has provided us alternative feasible, safe and effective options for treatment of patients who are otherwise not medically stable to undergo complex cranial surgical interventions. This paper review advances in treatment of intracranial pathologies, and how the neurosurgeons and other medical providers at the University of Missouri-Columbia (UMC) are optimizing these treatments for their patients.

Surgical Technique and Nuances of Resection of a Trochlear Schwannoma: Operative Video.

Cranial nerve schwannomas accounts for around 8% of all benign intracranial tumors, arising most commonly from the vestibular nerve, followed by the trigeminal nerve and other lower cranial nerves. However, trochlear schwannoma in a patient without neurofibromatosis-2 are extremely rare and to date, fewer than 100 cases have been reported in the literature. They are either asymptomatic or present with ophthalmologic or neurologic symptoms. Diplopia is the most common initial symptom. As the tumor grows, it can compress the surrounding brainstem and other cranial nerves, causing neurologic symptoms. Asymptomatic lesions are detected incidentally following imaging for some other reason. There are no clear guidelines for the management of these tumors. In general, small asymptomatic tumors are closely observed by serial imaging and symptomatic or larger tumors are managed by surgical excision and/or stereotactic radiosurgery.1-7 Here we present a 41-year-old female patient with incidentally detected left trochlear schwannoma during the follow-up magnetic resonance imaging (MRI) scans. She was followed up regularly with multiple repeat MRI. Recently she started complaining of occasional headaches, and MRI showed a left peimesencephalic cistern tumor causing mass effect on the ipsilateral midbrain. There was also significant brainstem edema. Hence she underwent left retromastoid suboccipital craniectomy, lateral supracerbellar approach, and complete excision of the tumor. Postoperatively the patient had an uneventful recovery without any new neurologic deficits. At 6 months' follow-up the patient is doing well.

Uncharted Waters of Machine and Deep Learning for Surgical Phase Recognition in Neurosurgery.

Recent years have witnessed artificial intelligence (AI) make meteoric leaps in both medicine and surgery, bridging the gap between the capabilities of humans and machines. Digitization of operating rooms and the creation of massive quantities of data have paved the way for machine learning and computer vision applications in surgery. Surgical phase recognition (SPR) is a newly emerging technology that uses data derived from operative videos to train machine and deep learning algorithms to identify the phases of surgery. Advancement of this technology will be key in establishing context-aware surgical systems in the future. By automatically recognizing and evaluating the current surgical scenario, these intelligent systems are able to provide intraoperative decision support, improve operating room efficiency, assess surgical skills, and aid in surgical training and education. Still in its infancy, SPR has been mainly studied in laparoscopic surgeries, with a contrasting stark lack of research within neurosurgery. Given the high-tech and rapidly advancing nature of neurosurgery, we believe SPR has a tremendous untapped potential in this field. Herein, we present an overview of the SPR technology, its potential applications in neurosurgery, and the challenges that lie ahead.

Tribute to William Edward Hunt and Robert McDonald Hess Jr.: Pioneers in the Clinical Classification of Ruptured Intracranial Aneurysms.

William Edward Hunt (1921-1999) and Robert McDonald Hess Jr. (1931-2019) were pioneers in revolutionizing the early surgical management of ruptured intracranial aneurysms. Early on in his career as a professor of neurosurgery at Ohio State University, Dr. Hunt adopted a systematic method to identify clinical symptoms of patients presenting with subarachnoid hemorrhage as candidates for either immediate or delayed surgery. As an Ohio State University neurosurgery resident, Dr. Hess was an active key collaborator in Dr. Hunt's aneurysm studies. Described as a modification of the Botterell classification system, the Hunt-Hess scale grading the survival risk of undergoing immediate intracranial aneurysm surgery was implemented and validated across an 18-year consecutive patient series at White Cross Hospital, Columbus, Ohio. Dr. Hunt and Dr. Hess demonstrated that for patients with subarachnoid hemorrhage on admission with Hunt-Hess grades I and II, indicating retained consciousness and minimal neurological deficits, immediate surgical management afforded a <20% mortality rate. In comparison, patients with grade III or higher had a >50% mortality rate, suggesting that conservative management should be instead pursued. As the principal investigator, Dr. Hunt was widely regarded internationally as an expert in the field of treating intracranial aneurysms, eventually serving as a World Federation of Neurosurgical Societies (WFNS) committee member to also publish a universal subarachnoid hemorrhage grading scale. To pay tribute to Drs. Hunt and Hess for their substantial contributions, we present historical vignettes of their lives along with highlighting the role of the Hunt-Hess classification system in transforming management of ruptured aneurysms.

Aortic arch anomalies, embryology and their relevance in neuro-interventional surgery and stroke: A review.

BACKGROUND: Congenital aortic arch anomalies are commonly encountered during neurointerventional procedures. While some anomalies are identified at an early age, many are incidentally discovered later in adulthood during endovascular evaluations or interventions. Proper understanding of the normal arch anatomy and its variants is pivotal to safely navigate normal aortic arch branches and to negotiate the catheter through anomalies during neurointerventional procedures. This is particularly relevant in the increasingly "transradial first" culture of neurointerventional surgery. Moreover, some of these anomalies have a peculiar predilection for complications including aneurysm formation, dissection, and rupture during the procedure. Therefore, an understanding of these anomalies, their underlying embryological basis and associations, and pattern of circulation will help endovascular neurosurgeons and interventional radiologists navigate with confidence and consider relevant pathologic associations that may inform risk of cerebrovascular disease. METHODS: Here, we present a brief review of the basic embryology of the common anomalies of the aortic arch along with their neurological significances and discuss, through illustrative cases, the association of aortic arch anomalies with cerebral vascular pathology. CONCLUSIONS: Understanding the aortic arch anomalies and its embryological basis is essential to safely navigate the cerebral vascular system during neurointerventional surgeries.

Gamma Knife Radiosurgery in the Management of Hypothalamic Glioma: A Case Report with Long-Term Follow-Up.

BACKGROUND: Optic pathway/hypothalamic gliomas are rare pediatric brain tumors. The management paradigm for these challenging tumors includes chemotherapy, radiotherapy, or surgical resection, but the optimal management strategy remains elusive. Gamma knife radiosurgery (GKRS) has emerged as a promising treatment for such lesions as documented by a small number of cases in the literature. CASE PRESENTATION: We present a rare case of hypothalamic glioma in a 13-year-old girl who was referred to our service due to growth of an incidentally diagnosed hypothalamic lesion following head injury at the age of 8 years. The lesion demonstrated hypointensity on T1- and hyperintensity on T2-weighted imaging without contrast enhancement. Given the growth of the lesion on serial imaging, a stereotactic biopsy was performed demonstrating low-grade glioma. The patient underwent GKRS treatment with a marginal dose of 15 Gy at 50% isodose line for a tumor volume of 2.2 mL. Annual radiological surveillance over the next 17 years demonstrated a gradual shrinkage of the lesion until it completely disappeared. The patient is currently a healthy 31-year-old female without any visual, endocrine, or neurocognitive deficits. CONCLUSION: The outcome obtained after extended follow-up in our patient highlights the safety and efficacy of GKRS in the management of hypothalamic gliomas in pediatrics, which in turn can avoid potentially serious complications of surgery in this vulnerable patient population, especially in this sensitive location.

The contributions of William A. Hammond (1828-1900) to Civil War medicine & modern neurology.

William Alexander Hammond was an American military physician and a main driving force for the development of modern-day clinical Neurology in America. Hammond served as the 11th Surgeon General of the United States Army, acting during the Civil War. Throughout his time as Surgeon General, with influence from Florence Nightingale, Hammond enforced strict hygienic measures and called for the construction of pavilion style hospitals in order to decrease non-wound mortalities. He implemented further reformation of the American Medical Service that would improve efficiency and decrease general mortality for years to come. After his dismissal from the military service, Hammond continued to make meaningful achievements, spearheading the specialization of Neurology. He established the first private practice limited to diseases of the nervous system, published the first American Neurology textbook, coined the term "athetosis", and was the impetus for the formation of the American Neurological Association.

Current applications and safety profile of laser interstitial thermal therapy in the pediatric population: a systematic review of the literature.

OBJECTIVE: Laser interstitial thermal therapy (LITT) provides a minimally invasive alternative to open brain surgery, making it a powerful neurosurgical tool especially in pediatric patients. This systematic review aimed to highlight the indications and complications of LITT in the pediatric population. METHODS: In line with the PRISMA guidelines, the authors conducted a systematic review to summarize the current applications and safety profiles of LITT in pediatrics. PubMed and Embase were searched for studies that reported the outcomes of LITT in patients < 21 years of age. Retrospective studies, case series, and case reports were included. Two authors independently screened the articles by title and abstract followed by full text. Relevant variables were extracted from studies that met final eligibility, and results were pooled using descriptive statistics. RESULTS: The selection process captured 303 pediatric LITT procedures across 35 studies. Males comprised approximately 60% of the aggregate sample, with a mean age of 10.5 years (range 0.5-21 years). The LITT technologies used included Visualase (89%), NeuroBlate (9%), and Multilase 2100 (2%). The most common indication was treatment of seizures (86%), followed by brain tumors (16%). The mean follow-up duration was 15.6 months (range 1.3-48 months). The overall complication rate was 15.8%, which comprised transient neurological deficits, cognitive and electrolyte disturbances, hemorrhage, edema, and hydrocephalus. No deaths were reported. CONCLUSIONS: As of now, LITT's most common applications in pediatrics are focused on treating medically refractory epilepsy and brain tumors that can be difficult to resect. The safety of LITT can provide an attractive alternative to open brain surgery in the pediatric population.

Multiple cerebral hemorrhages in sepsis-disseminated intravascular coagulation versus septic embolism: An image report.

BACKGROUND: Septic emboli are commonly attributed to infective endocarditis and can present with a variety of symptoms including altered mental status and focal neurological deficits. Here, we reviewed images of septic emboli with hemorrhagic conversion in a patient with sepsis and a psoas abscess. We aim to show the classical image findings in septic embolism to brain, which is sparsely described in literature and the report differentiates the septic embolism from disseminated intravascular coagulation which can present with almost identical image findings. CASE DESCRIPTION: A 53-year-old male patient who was operated on for a right inguinal hernia developed a postoperative wound infection 2 weeks after surgery and was started on IV antibiotics. Despite medical management, his infection did not improve, prompting a computed tomography (CT) scan which revealed a psoas abscess. The abscess was drained, and antibiotics continued. A few days later, he developed altered sensorium prompting a head CT which revealed septic emboli and hemorrhage at the gray-white junction. Cultures grew multidrug-resistant Escherichia coli; the patient was treated with IV tigecycline and improved over the following 4 weeks. CONCLUSION: In patients with a known ongoing infectious process with hemodynamic stability who develop altered mental status in the setting of a normal coagulation profile, D-dimer, positive blood cultures, and absent signs of multiorgan failure, a diagnosis of septic emboli should be entertained. Although CT can reveal macrobleeds, MRI is more sensitive in confirming cerebral microbleeds. Thus, patients in sepsis with unexplained altered sensorium should undergo an MRI of the brain to rule out septic emboli and microbleeds.

Venous Thromboembolism Prophylaxis in Elective Neurosurgery: A Survey of Board-Certified Neurosurgeons in the United States and Updated Literature Review.

BACKGROUND: Venous thromboembolism (VTE) remains the single most important preventable cause of morbidity and mortality following neurosurgical procedures, with an incidence of approximately 16%. In the absence of stringent guidelines, the variation in current practice patterns could be considerable and was the underlying basis for this study. OBJECTIVES: Our objective is to evaluate the modality of thromboprophylaxis used by neurosurgeons. METHODS: In line with "CHERRIES" (Checklist for Reporting Results of Internet E-Surveys) guidelines, an online survey regarding postoperative VTE prophylaxis following elective neurosurgical procedures was created using Google Forms and distributed to 1500 board-certified neurosurgeons in the United States. RESULTS: A total of 370 board-certified neurosurgeons (24.7%) responded to the survey. Sequential compression device was the only primary method of thromboprophylaxis used by 27.2% and 26.5% of respondents after elective craniotomy for tumor resection and spine surgery, respectively. Of the chemical prophylaxis, subcutaneous heparin 5000 U every 8 hours was the most commonly used medication followed by enoxaparin 40 mg daily. Most responders were comfortable starting chemical prophylaxis on postoperative day 1, followed by day 2 and day 3 in both types of surgeries. The mean postoperative time of chemical prophylaxis initiation was significantly more delayed by respondents with longer years in practice. CONCLUSIONS: This study highlights the variation in practice between neurosurgeons in managing postoperative VTE prophylaxis after elective spine and cranial surgeries. In lieu of this variation, our results showed that most neurosurgeons are comfortable starting chemical prophylaxis as soon as postoperative day 1 following both types of procedures.

Does preoperative embolization improve outcomes of meningioma resection? A systematic review and meta-analysis.

Current evidence regarding the benefit of preoperative embolization (POE) of meningiomas is inconclusive. This systematic review and meta-analysis aims to evaluate the safety profile of the procedure and to compare outcomes in embolized versus non-embolized meningiomas. PubMed was queried for studies after January 1990 reporting outcomes of POE. Pertinent variables were extracted and synthesized from eligible articles. Heterogeneity was assessed using I2, and random-effects model was employed to calculate pooled 95% CI effect sizes. Publication bias was assessed using funnel plots and Harbord's and Begg's tests. Meta-analyses were used to assess estimated blood loss and operative duration (mean difference; MD), gross-total resection (odds ratio; OR), and postsurgical complications and postsurgical mortality (risk difference; RD). Thirty-four studies encompassing 1782 preoperatively embolized meningiomas were captured. The pooled immediate complication rate following embolization was 4.3% (34 studies, n = 1782). Although heterogeneity was moderate to high (I2 = 35-86%), meta-analyses showed no statistically significant differences in estimated blood loss (8 studies, n = 1050, MD = 13.9 cc, 95% CI = -101.3 to 129.1), operative duration (11 studies, n = 1887, MD = 2.4 min, 95% CI = -35.5 to 30.8), gross-total resection (6 studies, n = 1608, OR = 1.07, 95% CI = 0.8-1.5), postsurgical complications (12 studies, n = 2060, RD = 0.01, 95% CI = -0.04 to 0.07), and postsurgical mortality (12 studies, n = 2060, RD = 0.01, 95% CI = 0-0.01). Although POE is relatively safe, no clear benefit was observed in operative and postoperative outcomes. However, results must be interpreted with caution due to heterogeneity and selection bias between studies. Well-controlled future investigations are needed to define the patient population most likely to benefit from the procedure.

Resection of Foramen Magnum Meningioma through Modified Far Lateral Approach: Surgical Principles and Technical Nuances.

Objectives Safe maximal resection is the basic principle of cranial base surgery and the grade of resection is an important factor influencing the prognostic outcome. This operative video highlights the surgical principles and technical nuances in the microsurgical resection of foramen magnum meningioma (FMM). Case Description The surgery was performed in a 45-year-old lady who presented with hoarseness of voice and spastic quadriparesis (grade 4/5). On imaging, FMM with mass effect on brainstem and spinal cord was identified. The tumor was gross totally resected through modified far lateral approach with minimal occipital condyle drilling. This video demonstrates the surgical techniques of tumor resection including early devascularization, operating in the arachnoid plane to dissect the neurovascular structures, piecemeal decompression, sharp dissection to separate tumor from lower cranial nerves (LCN), identifying the brainstem veins, and resecting the lesion from tumor-brainstem interface. Postoperatively, she had significant neurological improvement and the magnetic resonance imaging revealed excellent radiological outcome ( Figs. 1 and 2 ). Conclusion The surgery of FMM is challenging due to the deep surgical corridor, critical location, close proximity with various neurovascular structures, firm consistency, and high vascularity of the tumor. The modified far lateral approach by preserving the occipital condyle may prevent the postoperative incidence of craniovertebral junction instability. The key operative principles to achieve the best surgical outcome include careful dissection along the arachnoid plane, gentle handling of cranial nerves, veins, and perforator vessels, avoidance of traction on brainstem and spinal cord, intraoperative neurophysiological monitoring, proper hemostasis, and meticulous dural closure. The link to the video can be found at: https://youtu.be/1qvAeUmNIUw .

Multi-modal endovascular management of traumatic pseudoaneurysm and arteriovenous fistula of the ascending cervical artery: A technical report and review of literature.

OBJECTIVE: The management of traumatic pseudoaneurysm (PA) with concomitant arteriovenous fistula (AVF) arising from the thyrocervical trunk is challenging and rarely reported. Here, the usefulness of a multi-modal endovascular strategy for management of traumatic PA and AVF arising from the thyrocervical trunk is presented. A literature review describing unique clinical features and management strategies of traumatic vascular lesions of the thyrocervical trunk is included. METHODS: A 58-year-old man presented with two PAs arising from the ascending cervical artery (AsCA) and a robust AVF between the AsCA and the left vertebral venous plexus which arose acutely after a stabbing incident. These lesions were managed with endovascular vessel sacrifice via coiling and controlled Onyx injection. Relevant literature was identified via a targeted search of the PubMed database. RESULTS: Post-management angiography demonstrated complete occlusion of the two traumatic PAs and successful disconnection of the concomitant AVF. Our literature review demonstrates a shift in preferred management approach from invasive surgery to endovascular treatment due to the lower risk and cosmetic preferability. CONCLUSION: Timely treatment of enlarging PA is necessary for reducing associated morbidity and mortality. While surgical resection has been the mainstay therapy, endovascular management has gained popularity in recent years. The choice of endovascular technique is variable and should be individualized based on patient's clinical status, associated risk factors, and lesion morphology. We have shown that parent vessel sacrifice is safe and effective. Reconstruction with a combination of stents, coils, glue, or liquid embolics may be necessary when collateral flow is limited.

Jacques Forestier: Forgotten Contributions of a Rheumatologist to Spine Surgery.

Jacques Forestier (1890-1978) was a well-known rheumatologist and radiologist whose innovations have revolutionized spinal neurosurgery and rheumatology. He was well known as "Doctor Lipiodol" for his accidental discovery of spinal myelography, which he later extrapolated for use in many body cavities and their pathologies. He was the first to describe "senile ankylosing hyperostosis of the spine," which was later renamed "diffuse idiopathic skeletal hyperostosis." Furthermore, he is credited with the first use of gold salts as a disease-modifying therapy for rheumatoid arthritis. We have presented a historical vignette to chronicle the life of Jacques Forestier and his contributions to the field of spinal neurosurgery.

Intramedullary Spinal Cord Metastasis from Primary Lung Neuroendocrine Carcinoma: A Case Report and Operative Video.

BACKGROUND: Intramedullary spinal cord metastasis (ISCM) account for a minority of all spinal cord tumors. Rarely, symptoms from ISCM may be the initial presentation of an unknown primary carcinoma. Intramedullary metastasis from a second malignancy or from an unknown neuroendocrine malignancy is extremely rare and has never been reported in the literature. Because of the rarity of these tumors and the low volume of cases, well-defined treatment guidelines do not exist for the management of ISCM. Here we present a rare and one of the first reports of an intramedullary metastatic neuroendocrine tumor. CASE DESCRIPTION: A 66-year-old woman with a history of breast cancer presented with worsening bilateral lower extremity numbness for 2 months. Imaging revealed an intramedullary spinal cord tumor at the T4 level. The patient underwent microsurgical resection of the intramedullary spinal cord tumor. At operation, the tumor had an exophytic component. Subtotal resection was achieved. Pathology revealed a neuroendocrine metastasis, likely pulmonary in origin. She achieved partial resolution of neurologic symptoms at follow-up. CONCLUSIONS: Neuroendocrine ISCM are rare and lack well-defined treatment guidelines. Care should be individualized in these cases. Whenever feasible, surgical resection should be considered. Despite multidisciplinary care, the prognosis is dismal with limited life expectancy. Larger, multiinstitutional, or national database studies are needed that compare treatment modalities in the management of ISCM to identify the therapy with the best outcomes.

Lateral Myelotomy for Resection of a Ruptured Intramedullary Cervico-Thoracic Cavernous Malformation.

BACKGROUND AND IMPORTANCE: Intramedullary spinal cord cavernous malformations represent 5% to 12% of spinal vascular disease. Most patients present with acute or progressive neurological symptoms, including motor weakness or sensory loss. Surgical resection is the only definitive management and is recommended for symptomatic lesions that are surgically accessible. CLINICAL PRESENTATION: A 35-yr-old woman presented with a sudden onset of pain and temperature sensation loss in the left lower extremity. Magnetic resonance imaging of the spine showed a hemorrhage located ventral and slightly lateral to the right of the midline of the spinal cord from C7 through T3. Ultimately, a right lateral myelotomy between the ventral and dorsal roots was performed, and the cavernous malformation was removed. Postoperative imaging confirmed gross total resection of the cavernous malformation. CONCLUSION: In this article, we report a highly unusual case of a multisegment, ruptured intramedullary cavernous malformation that was ultimately resected through a lateral myelotomy approach. This case demonstrates that a lateral approach to the spinal cord substance can be utilized for ruptured cavernous malformation, especially if there is hemorrhage at the surface of the spinal cord. This can be used as an entry into the anterolateral compartment of the spinal cord, which would otherwise be regarded as a highly morbid approach due to the sensory deficits induced. We believe this entry point to the spinal cord is feasible in highly select cases such as this.

Lumbosacral extradural extramedullary hematopoiesis in thalassemia major causing spinal canal stenosis.

BACKGROUND: Extramedullary hematopoiesis (EH) is common in patients with ineffective erythropoiesis like thalassemia major (TM). EH commonly involves intra-abdominal organs (e.g., spleen and liver), but rarely involves vertebral bodies. Here, we reviewed images of EH contributing to spinal canal stenosis. CASE DESCRIPTION: A 19-year-old male with beta-thalassemia major (TM) presented with pain and bilateral lower extremity neurogenic claudication. Bilaterally, on examination, he had positive straight leg raising to 30°, a loss of the Achilles responses, and decreased pain appreciation in the L5S1 distributions. The lumbar MR showed anterior epidural lobulated mass lesions at L5 and S1, contributing to marked canal stenosis. Following an L5/S1 laminectomy for decompression, the biopsy revealed extramedullary hematopoietic tissue. CONCLUSION: Patients presenting with the lower extremity symptoms/signs, ranging from low back pain to neurogenic claudication and even paraplegia, may have EH secondary to TM. Treatment options include hypertransfusion, local radiation therapy, and/or surgical decompression.

Endoscope-Assisted Retromastoid Intradural Suprameatal Approach for Trigeminal Schwannoma.

BACKGROUND AND INTRODUCTION: Dumbbell trigeminal schwannoma is the second most common type of intracranial schwannomas. OBJECTIVE: Herein, we are describing and presenting a video of left trigeminal dumbbell schwannoma with a predominant posterior fossa component (modified Samii's grade C1), operated through left Retromastoid Intradural Suprameatal Approach (RISA). We demonstrate a step by step technique of a previously defined procedure for educational purpose. SURGICAL TECHNIQUE: The patient was placed in the right lateral position, and left retromastoid craniotomy was done. Dura was opened based on transverse and sigmoid sinus to expose tumors in the suprameatal region. The tumor removed piecemeal under the microscope, and later endoscope was introduced to identify and remove the residual tumor in the superolateral part of Meckel's cave. RESULTS: The patient had an uneventful recovery. CONCLUSION: Trigeminal schwannoma with a predominantly posterior fossa component can be excised through retromastoid sub-occipital craniotomy. Endoscopic-assisted microsurgery should be considered in all skull base tumors. Aim for complete excision, but safe maximal resection with GKRS for residual can be considered in difficult cases.