Exploring optimal microscopic keyhole access to the skull base: an anatomical evaluation of transciliary supraorbital and transpalpebral orbitofrontal craniotomy approaches.

PURPOSE: The past two decades have witnessed the rise of keyhole microscopic minimally invasive surgeries, including the transciliary supraorbital approach (TCA) and transpalpebral approach (TPA), commonly known as the transorbital approach. This study aims to elucidate the nuances, specific indications, and advantages of each approach. METHODS: A series of dissections were conducted on five formalin-fixed, alcohol-preserved cadaver heads. The TCA was performed on one side, and the TPA on the other. Virtual measurements of working angles for both approaches were recorded. Additionally, three clinical cases were presented to illustrate the practical application of the techniques. RESULTS: For TCA, the craniotomy dimensions were 1.7 cm x 2.5 cm (Cranial-Caudal (CC) x Lateral-Lateral (LL)), while for TPA, they measured 2.1 cm x 2.9 cm (CC x LL). The measurements of anterior clinoid processes (ACP) were obtained and compared between approaches. In the TCA, the mean ipsilateral ACP measurement was 62 mm (Range: 61 -63 mm), and the mean contralateral ACP measurement was 71.2 mm (Range: 70 -72 mm). In TPA, these measurements were 47.8 mm (Range: 47 -49 mm) and 62.8 mm (Range: 62 -64 mm), respectively. TCA exhibited an average cranial-caudal angle of 14.9°, while TPA demonstrated an average of 8.3°. CONCLUSION: The anterior cranial fossa was better exposed by a TCA, which also featured shorter operative times, enhanced midline visualization, and a quicker learning curve. Conversely, the middle fossa was better exposed by a TPA, making it an excellent option for middle fossa pathologies, including those in the anterior temporal lobe. After sphenoid bone wing drilling, the TPA offers superior visualization from the lateral to the medial aspect and enhances the CC angle. Additionally, the TPA reduces the risk of postoperative frontalis palsy based on anatomic landmarks. However, the TPA requires a greater cranial osteotomy, and due to unfamiliarity with eyelid anatomy, the learning curve for most neurosurgeons is lengthier for this procedure.

Intra-operative hypertension as a predictor of surgical outcomes in microvascular decompression surgery for trigeminal neuralgia.

PURPOSE: The trigeminocardiac reflex (TCR) has traditionally been characterized by a sudden decrease in heart rate, asystole, or hypotension during the manipulation of the trigeminal nerve (MTN) or its branches. While this classical TCR is well-documented, there is limited literature on alternative forms of TCR, such as the development of intraoperative hypertension (HTN) or tachycardia, and the underlying pathogenesis. Furthermore, a gap exists in understanding the correlation between intraoperative blood pressure readings and postoperative outcomes, particularly regarding pain relief in patients with trigeminal neuralgia (TN). Our study aims to examine intraoperative blood pressure trends during microvascular decompression (MVD) for TN and assess their impact on postoperative outcomes. METHODS: We selected 90 patients who underwent MVD for TN treatment. Blood pressure and heart rate were recorded both preoperatively and during the procedure, specifically during the MTN period, using an arterial line. The Barrow Neurological Institute (BNI) Pain Scale was calculated for all patients both pre- and post-operatively to evaluate pain relief after surgery. RESULTS: The mean age of the patients was 61.0 ± 12.35 years, with 64.4% being females. Classical TCR (hypotension) was observed in only 2.2% of patients, whereas 80% of patients developed hypertension (≥ 140/90) during MTN. The mean preoperative systolic blood pressure was 128 ± 22.25, and the mean intraoperative systolic blood pressure during MTN was 153.1 ± 20.2. An analysis of covariance, utilizing either preoperative BNI or duration of symptoms as covariate variables, revealed a statistically significant association between intraoperative HTN and postoperative BNI. A linear regression model demonstrated that intraoperative HTN following MTN significantly predicted a lower postoperative BNI score (p = 0.006). CONCLUSIONS: Intraoperative HTN during MTN, an observed yet underexplored phenomenon, demonstrated a correlation with improved postoperative outcomes. Furthermore, it is recommended to conduct additional investigations into potential neurovascular conflicts in patients not manifesting intraoperative HTN following MTN. A comprehensive understanding of TCR, encompassing its various forms, is vital for optimizing surgical management. This study underscores the imperative for further research to unravel the mechanisms linking intraoperative HTN to surgical outcomes in TN patients.

Plant lectins and their usage in preparing targeted nanovaccines for cancer immunotherapy.

Plant lectins, a natural source of glycans with a therapeutic potential may lead to the discovery of new targeted therapies. Glycans extracted from plant lectins are known to act as ligands for C-type lectin receptors (CLRs) that are primarily present on immune cells. Plant-derived glycosylated lectins offer diversity in their N-linked oligosaccharide structures that can serve as a unique source of homogenous and heterogenous glycans. Among the plant lectins-derived glycan motifs, Man9GlcNAc2Asn exhibits high-affinity interactions with CLRs that may resemble glycan motifs of pathogens. Thus, such glycan domains when presented along with antigens complexed with a nanocarrier of choice may bewilder the immune cells and direct antigen cross-presentation - a cytotoxic T lymphocyte immune response mediated by CD8+ T cells. Glycan structure analysis has attracted considerable interest as glycans are looked upon as better therapeutic alternatives than monoclonal antibodies due to their cost-effectiveness, reduced toxicity and side effects, and high specificity. Furthermore, this approach will be useful to understand whether the multivalent glycan presentation on the surface of nanocarriers can overcome the low-affinity lectin-ligand interaction and thereby modulation of CLR-dependent immune response. Besides this, understanding how the heterogeneity of glycan structure impacts the antigen cross-presentation is pivotal to develop alternative targeted therapies. In the present review, we discuss the findings on structural analysis of glycans from natural lectins performed using GlycanBuilder2 - a software tool based on a thorough literature review of natural lectins. Additionally, we discuss how multiple parameters like the orientation of glycan ligands, ligand density, simultaneous targeting of multiple CLRs and design of antigen delivery nanocarriers may influence the CLR targeting efficacy. Integrating this information will eventually set the ground for new generation immunotherapeutic vaccine design for the treatment of various human malignancies.

Frontotemporal craniotomy with orbital osteotomy for superior hypophyseal artery aneurysm clipping.

Superior hypophyseal artery (SHA) aneurysms are rare paraclinoid aneurysms with a mortality rate as high as 3%-6%. Surgical clipping of these aneurysms is technically challenging due to the surrounding anatomy. The large size and complicated surrounding anatomy make endovascular coiling very difficult. Here we present the case of a ruptured right SHA aneurysm. The authors present technical nuances of the clipping using an exoscope rather than a traditional microscope. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23157.

Frontotemporal Orbitozygomatic Transcavernous Approach: Stepwise Cadaveric Dissection for a Safe Corridor.

Background Advances in skull base surgery have increased the need for a detailed understanding of skull base anatomy and its intrinsic relationship to surrounding structures. This has resulted in an improvement in patient outcomes. The frontotemporal orbitozygomatic (FTOZ) transcavernous approach (TCA) is an excellent option for treating complex lesions involving multiple compartments of the skull base, including the sellar and parasellar, third ventricle, orbit, and petroclival region. Objective This article aimed to provide a detailed cadaveric dissection accompanying a thorough procedure description, including some tips and pitfalls of this technique. Methods Microsurgical dissection was performed in four freshly injected cadaver heads at the Cranial Base Neuroanatomy Laboratory, Cleveland Clinic Florida. The FTOZ TCA was performed on both sides of the four specimens. The advantages and disadvantages were discussed based on the anatomic nuances of this approach. Results The FTOZ TCA represented a wide access to the anterior, middle, and posterior fossa. When combined with an anterior clinoidectomy, it allowed for significant and safe internal carotid artery mobilization. This approach created numerous windows, including opticocarotid, carotid-oculomotor, supratrochlear, infratrochlear, anteromedial, anterolateral, and posteromedial triangles. The only drawback was the length of the dissection and the level of surgical acumen required to perform it. Conclusion Despite its technical difficulty, the FTOZ TCA should be considered for the surgical management of basilar apex aneurysms and tumors surrounding the cavernous sinus, sellar/parasellar, retrochiasmatic, and petroclival region. Continuous training and dedicated time in the skull base laboratory can help achieve the necessary skills required to perform this approach.

Occipital-interhemispheric transtentorial pineal mass resection.

The occipital approach for pineal tumors was first described by James Poppen in 1966. Since then, it has been widely used for accessing deep-seated tumors as it offers a wider surgical view than the supracerebellar transtentorial approach. This video demonstrates the technical nuances of the occipital transtentorial approach and the exoscopic dissection of a pineal gland tumor in a 66-year-old male. Use of the exoscope over the microscope provides certain ergonomic advantages and improves surgical workflow, as demonstrated here. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23161.

Subaxial Cervical Spine Motion With Different Sizes of Head-supported Mass Under Accelerative Forces.

INTRODUCTION: The evolution of military helmet devices has increased the amount of head-supported mass (HSM) worn by warfighters. HSM has important implications for spine biomechanics, and yet, there is a paucity of studies that investigated the effects of differing HSM and accelerative profiles on spine biomechanics. The aim of this study is to investigate the segmental motions in the subaxial cervical spine with different sizes of HSM under Gx accelerative loading. METHODS: A three-dimensional finite element model of the male head-neck spinal column was used. Three different size military helmets were modeled and incorporated into head-neck model. The models were exercised under Gx accelerative loading by inputting low and high pulses to the cervical vertebra used in the experimental studies. Segmental motions were obtained and normalized with respect to the non-HSM case to quantify the effect of HSM. RESULTS: Segmental motions increased with an increase in velocity at all segments of the spine. Increasing helmet size resulted in larger motion increases. Angulations ranged from 0.9° to 9.3° at 1.8 m/s and from 1.3° to 10.3° at 2.6 m/s without a helmet. Helmet increased motion between 5% to 74% at 1.8 m/s. At 2.6 m/s, the helmet increased segmental motion anywhere from 10% to 105% in the subaxial cervical spine. The greatest motion was seen at the C5-C6 level, followed by the C6-C7 level. CONCLUSIONS: The subaxial cervical spine experiences motion increases at all levels at both velocity profiles with increasing HSM. Larger helmet and greater impact velocity increased motion at all levels, with C5-C6 demonstrating the largest range of motion. HSM should be minimized to reduce the risk of cervical spine injury to the warfighter.

Impact of nanoparticles on amyloid ß-induced Alzheimer's disease, tuberculosis, leprosy and cancer: a systematic review.

Nanotechnology is an interdisciplinary domain of science, technology and engineering that deals with nano-sized materials/particles. Usually, the size of nanoparticles lies between 1 and 100 nm. Due to their small size and large surface area-to-volume ratio, nanoparticles exhibit high reactivity, greater stability and adsorption capacity. These important physicochemical properties attract scientific community to utilize them in biomedical field. Various types of nanoparticles (inorganic and organic) have broad applications in medical field ranging from imaging to gene therapy. These are also effective drug carriers. In recent times, nanoparticles are utilized to circumvent different treatment limitations. For example, the ability of nanoparticles to cross the blood-brain barrier and having a certain degree of specificity towards amyloid deposits makes themselves important candidates for the treatment of Alzheimer's disease. Furthermore, nanotechnology has been used extensively to overcome several pertinent issues like drug-resistance phenomenon, side effects of conventional drugs and targeted drug delivery issue in leprosy, tuberculosis and cancer. Thus, in this review, the application of different nanoparticles for the treatment of these four important diseases (Alzheimer's disease, tuberculosis, leprosy and cancer) as well as for the effective delivery of drugs used in these diseases has been presented systematically. Although nanoformulations have many advantages over traditional therapeutics for treating these diseases, nanotoxicity is a major concern that has been discussed subsequently. Lastly, we have presented the promising future prospective of nanoparticles as alternative therapeutics. In that section, we have discussed about the futuristic approach(es) that could provide promising candidate(s) for the treatment of these four diseases.

Enhanced recovery after surgery in patients with normal pressure hydrocephalus undergoing ventriculoperitoneal shunting procedures.

OBJECTIVE: Patients with idiopathic normal pressure hydrocephalus (iNPH) who undergo ventriculoperitoneal shunt (VPS) placement often belong to an older demographic, putting them at increased risk of postoperative delirium and related complications. Recent literature documenting the use of Enhanced Recovery After Surgery (ERAS) protocols in various disciplines of surgery has shown improved clinical outcomes, faster discharge, and lower readmission rates. Early return to a familiar environment (i.e., discharged home) is a well-known predictor of reduced postoperative delirium. However, ERAS protocols are uncommon in neurosurgery, especially intracranial procedures. We developed a novel ERAS protocol for patients with iNPH undergoing VPS placement to gain further insight regarding postoperative complications, specifically delirium. METHODS: We studied 40 patients with iNPH with indications for VPS. Seventeen patients were selected at random to undergo the ERAS protocol, and twenty-three patients underwent the standard VPS protocol. The ERAS protocol consisted of measures to reduce infection, manage pain, minimize invasiveness, confirm procedural success with imaging, and shorten the length of stay. Pre-operative American Society of Anesthesiologists (ASA) grade was collected for each patient to indicate baseline risk. Rates of readmission and postoperative complications, including delirium and infection, were collected at 48 h, 2 weeks, and 4 weeks postoperatively. RESULTS: There were no perioperative complications among the 40 patients. There was no postoperative delirium in any of the ERAS patients. Postoperative delirium was observed in 10 of 23 non-ERAS patients. There was no statistically significant difference between the ASA grade between the ERAS and non-ERAS groups. CONCLUSIONS: We described a novel ERAS protocol for patients with iNPH receiving VPS focusing on an early discharge. Our data suggest that ERAS protocols in VPS patients might reduce the incidence of delirium without increasing the risk of infection or other postoperative complications.

Anatomical Description and Literature Review of the Endoscopic Endonasal Transclival Transodontoid Approach Combined with Endoscopic Transoral Decompression to the Anterior Craniovertebral Junction: A New Strategy.

OBJECTIVE: To describe and evaluate the steps required to perform a combined endoscopic endonasal/transoral transclival transodontoid approach for anterior decompression of the craniovertebral junction. METHODS: The endoscopic endonasal transclival transodontoid approach combined with endoscopic transoral decompression was performed on 4 cadaveric specimens. Evaluation of this combined technique; a review of the literature; and the nuances, advantages, and pitfalls are reported. RESULTS: Adequate wide anterior decompression was achieved in all specimens. This combined approach allowed the preservation of the anterior arch of C1 without injuring the eustachian tube anatomy and avoiding internal carotid artery manipulation. CONCLUSIONS: Mastery of both techniques allows for a safe and comfortable surgical corridor. The transoral and transnasal approaches should not be considered as either/or techniques, but rather as a complement to each other. However, as with all new or developing techniques, there is a steep learning curve, which requires ample training in the skull base laboratory.

Endoscopic endonasal optic nerve sheath decompression (EONSD) for idiopathic intracranial hypertension: Technical details and meta-analysis.

BACKGROUND: The neurosurgical management of idiopathic intracranial hypertension (IIH) remains controversial. Although shunting and newer endovascular stenting techniques are part of the neurosurgical armamentarium to treat medically refractory IIH symptoms, optic nerve sheath fenestration has traditionally been performed by ophthalmologists. OBJECTIVE: We present a detailed cadaveric dissection that simulates the endoscopic endonasal optic nerve sheath decompression (EONSD) technique along with the literature review. METHODS: EONSD was performed in four freshly injected cadaveric specimens. Additionally, a systematic review from different electronic databases has been done. RESULTS: Bilateral EONSD was performed in all specimens without significant technical difficulties. Based on our experience, there is no need to expose the periorbita or orbital apex. The primary anatomic landmarks were the optic canal, the lateral opticocarotid recess, the tuberculum, the limbus, and the clinoid segment of the internal carotid artery. Based on the systematic review, 68 patients (77.9% female) underwent EONSD, with a mean age of 33.4 ± 6.9 years in adult patients. Follow-up ranged from 3 to 58 months across different studies. The pooled meta-analysis showed headache, papilledema, and visual disturbance improvement in 78% [95%CI 0.65-0.90], 72% [95%CI 0.61-0.83], and 88% [95%CI 0.80-0.96] of cases who underwent EONSD, respectively. The subgroup analysis showed there was no statistically significant difference between unilateral and bilateral EONSD in terms of different measured outcomes. CONCLUSION: EONSD is a feasible surgical procedure that may obviate the need for shunting in patients with IIH. Although clinical studies showed that EONSD is a safe and effective technique, further studies are required to establish the preferences of either unilateral or bilateral approaches.

Incidence and Risk Factors for Superficial and Deep Vein Thrombosis in Post-Craniotomy/Craniectomy Neurosurgical Patients.

Background Venous thromboembolism (VTE) is quite common among post-operative neurosurgical patients. This study aims to identify the incidence of deep vein thrombosis (DVT) and superficial vein thrombosis (SVT) among post-craniotomy/craniectomy patients and further evaluate established hypercoagulability risk factors such as trauma, tumors, and surgery. Methodology This single-center retrospective study investigated 197 patients who underwent a craniotomy/craniectomy. The incidences of DVT and SVT were compared, along with laterality and peripherally inserted central catheter (PICC) line involvement. A multivariate logistic regression analysis was conducted to identify risk factors for post-craniotomy/craniectomy VTE. This model included variables such as age, post-operative days before anticoagulant administration, female sex, indications for surgery such as tumor and trauma, presence of a PICC line, and anticoagulant administration. Results Among the 197 post-craniotomy/craniectomy patients (39.6% female; mean age 53.8±15.7 years), the incidences of DVT, SVT, and VTE were 4.6%, 9.6%, and 12.2%, respectively. The multivariate logistic regression analysis found that increasing the number of days between surgery and administration of anticoagulants significantly increased the risk of VTE incidence (odds ratio 1.183, 95% CI 1.068-1.311, p = 0.001). Conclusions Contrary to existing evidence, this study did not find trauma or the presence of tumors to be risk factors for VTE. Future prospective studies should assess VTE risk assessment models such as "3 Bucket" or "Caprini" to develop universal guidelines for administering anticoagulant therapy to post-craniotomy/craniectomy patients that consider the timing of post-operative therapy initiation.