Creating a neuroanatomy education model with augmented reality and virtual reality simulations of white matter tracts

OBJECTIVE

The utilization of digital technologies has experienced a notable surge, particularly in cases where access to cadavers is constrained, within the context of practical neuroanatomy training. This study evaluates augmented reality (AR)- and virtual reality (VR)-based educational models for neuroanatomy education.

METHODS

Three-dimensional models were created using advanced photogrammetry. VR- and AR-based educational models were developed by arranging these 3D models to align with the learning objectives of neurosurgery residents and second-year medical students whose cadaveric training was disrupted due to an earthquake in Turkey. Participants engaged with and evaluated the VR- and AR-based educational models, followed by the completion of a 20-item graded user experience survey. A 10-question mini-test was given to assess the baseline knowledge level prior to training and to measure the achievement of learning objectives after training.

RESULTS

Forty neurosurgery residents were trained with a VR-based educational model using VR headsets. An AR-based educational model was provided online to 200 second-year medical students for their practical neuroanatomy lesson. The average correct answer rates before the training were 7.5/10 for residents and 4.8/10 for students. These rates were significantly improved after the training to 9.7/10 for residents and to 8.7/10 for students (p < 0.001). Feedback from the users concurred that VR- and AR-based training could significantly enhance the learning experience in the field of neuroanatomy.

CONCLUSIONS

VR/AR-based educational models have the potential to improve education. VR/AR-based training systems can serve as an auxiliary tool in neuroanatomy training, offering a realistic alternative to traditional learning tools.

Dynamic Lateral Semisitting Position for Supracerebellar Approaches: Technical Note and Case Series

BACKGROUND

It has always been a matter of debate which position is ideal for the supracerebellar approach. The risk of venous air embolism (VAE) is the major deterrent for surgeons and anesthesiologists, despite the fact that sitting and semisitting positions are commonly used in these operations.

OBJECTIVE

To demonstrate a reduction on the risk of VAE and tension pneumocephalus throughout the operation period while taking advantages of the semisitting position.

METHODS

In this study, 11 patients with various diagnoses were operated in our department using the supracerebellar approach in the dynamic lateral semisitting position. We used end-tidal carbon dioxide and arterial blood pressure monitoring to detect venous air embolism.

RESULTS

None of the patients had clinically significant VAE in this study. No tension pneumocephalus or major complications were observed. All the patients were extubated safely after surgery.

CONCLUSION

The ideal position, with which to apply the supracerebellar approach, is still a challenge. In our study, we presented an alternative position that has advantages of the sitting and semisitting positions with a lower risk of venous air embolism.

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

BACKGROUND

Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.

METHODS

This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low-middle-income countries.

RESULTS

In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of 'single-use' consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low-middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.

CONCLUSION

This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high- and low-middle-income countries.

Three-Dimensional Modeling and Extended Reality Simulations of the Cross-Sectional Anatomy of the Cerebrum, Cerebellum, and Brainstem

BACKGROUND

Understanding the anatomy of the human cerebrum, cerebellum, and brainstem and their 3-dimensional (3D) relationships is critical for neurosurgery. Although 3D photogrammetric models of cadaver brains and 2-dimensional images of postmortem brain slices are available, neurosurgeons lack free access to 3D models of cross-sectional anatomy of the cerebrum, cerebellum, and brainstem that can be simulated in both augmented reality (AR) and virtual reality (VR).

OBJECTIVE

To create 3D models and AR/VR simulations from 2-dimensional images of cross-sectionally dissected cadaveric specimens of the cerebrum, cerebellum, and brainstem.

METHODS

The Klingler method was used to prepare 3 cadaveric specimens for dissection in the axial, sagittal, and coronal planes. A series of 3D models and AR/VR simulations were then created using 360° photogrammetry.

RESULTS

High-resolution 3D models of cross-sectional anatomy of the cerebrum, cerebellum, and brainstem were obtained and used in creating AR/VR simulations. Eleven axial, 9 sagittal, and 7 coronal 3D models were created. The sections were planned to show important deep anatomic structures. These models can be freely rotated, projected onto any surface, viewed from all angles, and examined at various magnifications.

CONCLUSION

To our knowledge, this detailed study is the first to combine up-to-date technologies (photogrammetry, AR, and VR) for high-resolution 3D visualization of the cross-sectional anatomy of the entire human cerebrum, cerebellum, and brainstem. The resulting 3D images are freely available for use by medical professionals and students for better comprehension of the 3D relationship of the deep and superficial brain anatomy.

Interhemispheric Transcingulate Sulcus Approach to Deep-Seated Medial Frontal and Parietal Lesions-Fiber Dissection Study With Illustrative Cases

BACKGROUND

Surgery for lesions located in the medial frontal and parietal lobes can be quite challenging for neurosurgeons because of morbidities that may arise from damage to critical midline structures or intact neural tissue that need to be crossed to reach the lesion. In our anatomic studies, the cingulate sulcus was observed as an alternative access route for lesions located in medial frontal and parietal lobes.

OBJECTIVE

To explain the microsurgical anatomy of the medial hemisphere and cingulate sulcus and to demonstrate the interhemispheric transcingulate sulcus approach (ITCSA) with 3 clinical cases.

METHODS

Five formalin-fixed brain specimens, which were frozen at -18 °C for at least 2 weeks and then thawed under tap water, were gradually dissected from medial to lateral. Diffusion fiber tracking performed using DSI Studio software in data was provided by the Human Connectome Project. Clinical data of 3 patients who underwent ITCSA were reviewed.

RESULTS

Cingulate sulcus is an effortlessly identifiable continuous sulcus on the medial surface of the brain. Our anatomic dissection study revealed that the lesions located in the deep medial frontal and parietal lobes can be reached through the cingulate sulcus with minor injury only to the cingulum and callosal fibers. Three patients were treated with ITCSA without any neurological morbidity.

CONCLUSION

Deep-seated lesions in the medial frontal lobe and parietal lobe medial to the corona radiata can be approached by using microsurgical techniques based on anatomic information. ITCSA offers an alternative route to these lesions besides the known lateral transcortical/transsulcal and interhemispheric transcingulate gyrus approaches.

Osteoplastic Pterional Craniotomy: Success Rate of Surgery in Patient Aspect

AIM

To evaluate the effect of osteoplastic pterional craniotomy on temporal hollowing and its sequelae.

MATERIAL AND METHODS

A total of 97 patients who underwent pterional craniotomy for an aneurysm were analyzed retrospectively. Of these 97 patients, 63 underwent surgery via the conventional pterional approach and 34 underwent surgery via the osteoplastic pterional approach. The temporal muscle volume was calculated bilaterally on CT images obtained in the sixth postoperative month. The results obtained in the conventional and osteoplastic approaches were compared.

RESULTS

Of the 97 included patients, 45 were female and 52 were male. The mean patient age was 50.37 years. In the conventional group, 31 were female and 32 were male. In the osteoplastic group, 14 were female and 20 were male. The temporal muscle volume difference between the operated and non-operated side was not statistically significant in the osteoplastic group. However, the volume was slightly lesser on the operated side than on the non-operated side in the conventional group.

CONCLUSION

The osteoplastic pterional approach is superior to the conventional approach in preserving the muscle volume and function. Patients who underwent osteoplastic craniotomy demonstrated higher levels of satisfaction with their facial appearance compared to those who underwent craniotomy using the conventional pterional approach.

The Extreme Anterior Interhemispheric Transcallosal Approach for Pure Aqueduct Tumors: An Anatomical Study

AIM

To show the normal anatomy of the cerebral aqueduct, and the feasibility of the extreme anterior interhemispheric transcallosal approach to remove tumors within the aqueduct.

MATERIAL AND METHODS

This human cadaveric brain research was composed of ten formalin-fixed human brains and one injected head. The dissection was performed under an operative microscope with 6x to 40x magnification. The cerebral aqueduct anatomy was delineated along with the relationship to nearby structures in the extreme anterior interhemispheric transcallosal approach.

RESULTS

We described the anatomy of the cerebral aqueduct within the brain and showed that, with the proper angle for the extreme anterior interhemispheric transcallosal approach, lesions in the cerebral aqueduct can be reached in a single session without damaging periventricular structures.

CONCLUSION

The extreme anterior interhemispheric transcallosal approach provides a direct corridor to the cerebral aqueduct and, thus, is feasible for resecting pure aqueduct tumors in an already dilated intraventricular foramen.

Surgical Treatment of Trochlear Nerve Schwannomas: Case Series and Systematic Review

BACKGROUND AND OBJECTIVE

Cranial nerve schwannomas almost always arise from sensory or mixed nerves. Motor cranial nerves, such as the trochlear nerve, are rarely associated with schwannomas. No consensus has yet been made for surgical intervention because of the low number of reported cases of trochlear nerve schwannomas. This study comprises a systematic review of the literature and our experience for surgically treated trochlear nerve schwannomas.

METHODS

Three databases (Web of Science, PubMed, and Cochrane Library) were searched without date restrictions. Studies were included if they were published in the English literature and presented patients of any age who underwent surgical treatment for trochlear schwannoma. Data extracted from the included studies were combined with our experience.

RESULTS

Forty-one studies, presenting 43 patients, met the inclusion criteria. The total number of patients was 45 after our experience was added. The most common symptoms were diplopia (62.2%), headache (46.7%), and motor weakness (37.8%). Mean age during the diagnosis was 45.1 years. Although the subtemporal transtentorial approach (n = 14) is the most preferred method, its application has decreased in recent years. In the last decade, the lateral suboccipital approach (n = 11) has gained popularity. Residual postoperative trochlear nerve deficit was detected in 81% of patients. The probability of neurologic deficit was not statistically associated with tumor volume (P = 0.914), location (P = 0.669), or resection rate (P = 0.554).

CONCLUSIONS

Although trochlear schwannomas are rare and their treatment involves challenges, total resection with the proper approach provides the most desirable results.

Extreme lateral lumbar interbody fusion surgery with a robot-assisted system in a swine model

AIM

To evaluate the technical aspects of the Da Vinci Xi Surgical System in minimally invasive extreme lateral lumbar interbody fusion (XLIF) surgery in a swine model.

MATERIAL AND METHODS

Endoscopic discectomy and XLIF cage insertion were performed using a robot-assisted system. The time taken and the pros and cons of each steps were recorded.

RESULTS

A total of 4 ports were used for the surgical access; one for the camera, two for bipolar forcepses, and one auxiliary port for modified discectomy. Punch and curette were used for discectomy. The cage was inserted through the auxiliary port. Cage position was manipulated and checked by using the C-arm fluoroscopy. The operative time was 80 minutes. No complications or cage malposition was noted throughout the procedure.

CONCLUSION

This study shows that the robot-assisted XLIF approach is safe and feasible, and helps to protect the neurovascular structures. Moreover, a high image quality was also obtained during the procedure.

Qlone®: A Simple Method to Create 360-Degree Photogrammetry-Based 3-Dimensional Model of Cadaveric Specimens

BACKGROUND

Human cadavers are an essential component of anatomy education. However, access to cadaveric specimens and laboratory facilities is limited in most parts of the world. Hence, new innovative approaches and accessible technologies are much needed to enhance anatomy training.

OBJECTIVE

To provide a practical method for 3-dimensional (3D) visualization of cadaveric specimens to maximize the utility of these precious educational materials.

METHODS

Embalmed cadaveric specimens (cerebrum, brain stem, and cerebellum) were used. The 3D models of cadaveric specimens were built by merging multiple 2-dimensional photographs. Pictures were taken with standard mobile devices (smartphone and tablet). A photogrammetry program (Qlone®, 2017-2020, EyeCue Vision Technologies Ltd, Yokneam, Israel), an all-in-one 3D scanning and augmented reality technology, was then used to convert the images into an integrated 3D model.

RESULTS

High-resolution 360-degree 3D models of the cadaveric specimens were obtained. These models could be rotated and moved freely on different planes, and viewed from different angles with varying magnifications. Advanced editing options and the possibility for export to virtual- or augmented-reality simulation allowed for better visualization.

CONCLUSION

This inexpensive, simple, and accessible method for creating 360-degree 3D cadaveric models can enhance training in neuroanatomy and allow for a highly realistic surgical simulation environment for neurosurgeons worldwide.

Cellular blue nevus tumor presenting as a submandibular lymph node in a 16-year-old

The cellular blue nevus tumor is a type of dendritic melanocytic nevus that is typically benign and exceedingly rare. The incidence of all blue nevi is about 1%, usually affecting the adult population and appearing on the extremities, sacrococcygeal or gluteal regions. There have only been a handful of case reports cited in the literature where cellular blue nevi present in the head and neck region, usually affecting the scalp and young adult population (7, 8). As such, it is exceedingly rare to encounter a cellular blue nevus tumor in the neck or infiltrating into neck lymph nodes. Here we report a rare case of a cellular blue nevus tumor presenting as a right neck mass in a pediatric 16-year-old patient, shown to invade into the submandibular lymph node and surrounding soft tissue. It is important to be aware of the cellular blue nevus tumor as a differential diagnosis in pediatric neck masses. Histological evaluation is necessary to determine tumor aggression and malignant potential which can guide further treatment in pediatric patients.

The historical evolution of the fornix and its terminology: a review

The historical evolution of the fornix has not been sufficiently reviewed in the literature. In this article, we follow this evolution from the first mention of the fornix in animal dissections of the second century AD, to the legalization of cadaver dissection in the 1300 s, to the introduction of neural staining techniques and the microscope in the seventeenth century, to today. We summarize the focus of fornix studies on memory to reveal its relationship with the hippocampus. We then cover the detection of the fornix and its neural connections noninvasively with the advancement of radiological imaging techniques. Finally, we discuss the prominence of the fornix as a target for deep brain stimulation in Alzheimer's disease and post-traumatic brain injury memory disorders.

External carotid artery pseudoaneurysm following upper respiratory infection masquerading as a pharyngeal abscess in an 8-month-old

Pseudoaneurysms are very rare with an incidence of less than 0.1% in the pediatric population. Approximately 30 cases of carotid artery aneurysms in children have been published in the literature, usually affecting children over one year of age. We present one of the youngest cases in the literature; the patient is an 8-month old female with a strep throat infection complicated by pseudoaneurysm development of the external carotid artery. Because of the rarity of these lesions, there is little known regarding the types of clinical presentation and management. They are commonly the result of direct arterial trauma; however, they can also occur secondary to infection, connective tissue disease or arteritis. We are presenting a case with a highly atypical presentation. When present, pseudoaneurysms harbor the potential risk of life-threatening hemorrhage and warrant immediate management. It is important to be aware of cases and the treatment modalities used to guide future diagnosis and planning.

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

OBJECTIVE

Projections from the dentate nucleus (DN) follow a certain organized course to upper levels. Crossing and noncrossing fibers of the dentatorubrothalamic (DRT) tract terminate in the red nucleus and thalamus and have various connections throughout the cerebral cortex. We aimed to establish the microsurgical anatomy of the DN in relation to its efferent connections to complement the increased recognition of its surgical importance and also to provide an insight into the network-associated symptoms related to lesions and microsurgery in and around the region.

METHODS

The cerebellum, DN, and superior cerebellar peduncle (SCP) en route to red nucleus were examined through fiber dissections from the anterior, posterior, and lateral sides to define the connections of the DN and its relationships with adjacent neural structures.

RESULTS

The DN was anatomically divided into 4 areas based on its relation to the SCP; the lateral major, lateral anterosuperior, posteromedial, and anteromedial compartments. Most of the fibers originating from the lateral compartments were involved in the decussation of the SCP. The ventral fibers originating from the lateral anterosuperior compartment were exclusively involved in the decussation. The fibers from the posteromedial compartment ascended ipsilaterally and decussated, whereas most anteromedial fibers ascended ipsilaterally and did not participate in the decussation.

CONCLUSIONS

Clarifying the anatomofunctional organization of the DN in relation to the SCP could improve microneurosurgical results by reducing the complication rates during infratentorial surgery in and around the nucleus. The proposed compartmentalization would be a major step forward in this effort.

Cervical Venous Vascular Anatomy for Ventriculoatrial Shunt Applications: Anatomical Study and Surgical Approach Recommendation

AIM

Ventriculoatrial (VA) shunt applications are performed when applying ventriculoperitoneal shunt is not suitable. However, due to variations in the venous anatomy of the neck region and difficulties with venous vascular dissection, this procedure involves the risk of complications. This study aimed to develop an approach for atrial application of VA shunts after revealing the venous anatomy with facial and cervical anatomical dissections.

MATERIAL AND METHODS

Five cephalic cadavers were used in the study. Facial and cervical regions of the cephalic cadavers were examined with layer by layer anatomical dissection. Venous angiography and ultrasonography were performed to obtain additional data on the cervical venous vascular anatomy. Subsequently, we developed an approach for atrial catheter applications.

RESULTS

No anatomical variations were detected in the dissections. The common facial vein, which was formed by the facial vein and retromandibular vein, was observed to drain into the internal jugular vein. As a result of dissections and examinations, an incision approximately 2 cm below the mandible, extending from the projection of the submandibular notch to the trace of the angulus mandible, was considered adequate to expose the common facial vein for atrial catheter insertion.

CONCLUSION

The approach described in our study is appropriate for the application of an atrial catheter for VA shunts. Revealing the venous anatomy with examinations contributes to the success of the operation.

Endoscopic Untethering of Tight Filum Terminale: An Operative Technique

AIM

To demonstrate the various technical advantages of minimally invasive endoscopic untethering of tight filum terminale for the treatment of tethered cord syndrome (TCS).

MATERIAL AND METHODS

In five pediatric cases of TCS, we performed untethering by using the endoscopic technique. The age of the patients were 6, 7, 8, 9, and 12 years old. We used a nasal speculum of the transsphenoidal approach during the endoscopic surgical procedure.

RESULTS

All the procedures were performed uneventfully, except for one case with a split cord malformation that showed neurologic deterioration caused by excision of the diastematomyelic fibrous septum at the thoracic level (unrelated to the endoscopic procedure at the L5-S1 level). This patient was referred to a rehabilitation clinic 5 days after surgery and showed significant improvement by the third postoperative month. The other four patients were discharged 1 day after the operation.

CONCLUSION

Endoscopic release of filum terminale is a safe technique especially if it is performed with neuromonitoring. This technique may shorten the length of hospital stay and reduce perioperative blood loss. However, futher studies with a larger number of patients and long-term follow-up are needed.

Postmortem Dissections of Common Targets for Lesion and Deep Brain Stimulation Surgeries

BACKGROUND

The subthalamic nucleus (STN), globus pallidus internus (GPi), and pedunculopontine nucleus (PPN) are effective targets for deep brain stimulation (DBS) in many pathological conditions. Previous literature has focused on appropriate stimulation targets and their relationships with functional neuroanatomic pathways; however, comprehensive anatomic dissections illustrating these nuclei and their connections are lacking. This information will provide insight into the anatomic basis of stimulation-induced DBS benefits and side effects.

OBJECTIVE

To combine advanced cadaveric dissection techniques and ultrahigh field magnetic resonance imaging (MRI) to explore the anatomy of the STN, GPi, and PPN with their associated fiber pathways.

METHODS

A total of 10 cadaveric human brains and 2 hemispheres of a cadaveric head were examined using fiber dissection techniques. The anatomic dissections were compared with 11.1 Tesla (T) structural MRI and 4.7 T MRI fiber tractography.

RESULTS

The extensive connections of the STN (caudate nucleus, putamen, medial frontal cortex, substantia innominata, substantia nigra, PPN, globus pallidus externus (GPe), GPi, olfactory tubercle, hypothalamus, and mammillary body) were demonstrated. The connections of GPi to the thalamus, substantia nigra, STN, amygdala, putamen, PPN, and GPe were also illustrated. The PPN was shown to connect to the STN and GPi anteriorly, to the cerebellum inferiorly, and to the substantia nigra anteriorly and superiorly.

CONCLUSION

This study demonstrates connections using combined anatomic microdissections, ultrahigh field MRI, and MRI tractography. The anatomic findings are analyzed in relation to various stimulation-induced clinical effects. Precise knowledge of neuroanatomy, anatomic relationships, and fiber connections of the STN, GPi, PPN will likely enable more effective targeting and improved DBS outcomes.

Investigating the Knowledge, Attitudes and Behaviours of Parents Regarding Vaccine Rejection

Background

With an escalating prevalence, vaccine rejection is one of the ten threats to global health as identified by the World Health Organization in 2019. Vaccine rejection and hesitancy can be defined as the hesitancy of individuals to get vaccinated against diseases that can be prevented by vaccination. This study aimed to investigate the knowledge, attitudes and behaviours of parents who use primary healthcare services.

Methods

Conducted between August and September 2019, this study adopted a descriptive cross-sectional design. The sample size of the study was calculated to be 378, considering a 95% confidence interval and 80% power. The survey form, the data collection tool of the study, included questions concerning sociodemographic characteristics of individuals and their knowledge, attitudes and behaviours regarding vaccination. The data were analysed on SPSS 22.0. Chi-square test was used in statistical analyses, and the significance level was set as p &lt; 0.05.

Results

In the study group, 15.5% of the parents stated that they were hesitant about vaccines in childhood, 81.3% stated that their source of information on vaccines was healthcare staff and 28% stated that it was the internet. The hesitancy level was significantly high among those who believed that vaccines led to autism and infertility and those who did not trust pharmaceutical companies (p &lt; 0.05). The hesitancy level regarding vaccines was significantly lower among those whose source of information was healthcare staff, whereas it was significantly higher among those whose source of information was the internet (p &lt; 0.05).

Conclusions

Parents' beliefs that vaccines led to autism and infertility increased their hesitancy levels. The inaccurate information on the internet and social media increased their hesitancy levels. Hesitancy levels were lower among the parents who received information from healthcare staff.

Key messages

Healthcare staff should organise public trainings on vaccines to reduce the hesitancy levels of parents. Anti-vaccination statements on the internet and social media influence individuals’ vaccination behaviours.

Neurosurgical Practice During Coronavirus Disease 2019 (COVID-19) Pandemic

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly contagious life-threatening condition with unprecedented impacts for worldwide societies and health care systems. Since the first detection in China, it has spread rapidly worldwide. The increased burden has substantially affected neurosurgical practice and intensive modifications have been required in surgical scheduling, inpatient and outpatient clinics, management of emergency cases, and even in academic activities. In some systems, nonoverlapping teams have been created to minimize transmission among health care workers. In cases of a massive burden, neurosurgeons may need to be reassigned to COVID-19 wards, or teams from other regions may need to be sent to severely affected areas. Recommendations are as following. In outpatient practice, if possible, appointments should be undertaken via telemedicine. All staff assigned to the non-COVID treatment unit should be clothed in level 1 personal protective equipment. If possible, postponement is recommended for operations that do not require urgent or emergent intervention. All patients indicated for surgery must receive COVID-19 screening, including a nasopharyngeal swab and thorax computed tomography. Level 2 protection measures are appropriate during COVID-19-negative patients' operations. Operations of COVID-19-positive patients and emergency operations, in which screening cannot be obtained, should be performed after level 3 protective measures. During surgery, the use of high-speed drills and electrocautery should be reduced to minimize aerosol production. Screening is crucial in all patients because the surgical outcome is highly mortal in patients with COVID-19. All educational and academic conferences can be undertaken as virtual webinars.

Robotic Surgical Approach to the Mesial Temporal Region: A Preliminary Three-Dimensional Cadaveric Study of Technical Feasibility

OBJECTIVE

Robotic surgical systems are used worldwide in various fields. In this study, we present the advantages and disadvantages of the most common robotic surgical system, the da Vinci Xi system, in the supracerebellar transtentorial approach to the mesial temporal region and discuss options for its integration into neurosurgery.

METHODS

Our study was conducted at the Advanced Simulation and Applied Endoscopic Surgery Training and Research Center and Anatomy Laboratory. Four formalin-fixed human cadaveric head specimens with red silicone dye injected into their arterial structures and blue silicone dye injected into their venous structures were used in the study. Dissections were performed in microscopic and robotic stages. All phases were photographed using a three-dimensional photographic technique.

RESULTS

The mesial temporal lobe could be accessed via the supracerebellar transtentorial route with the use of the robotic system. We show that the robotic system can be used in difficult approaches and narrow regions with a wider exposure and superior image quality than with the microscopic approach, improving the ergonomics for the surgeon. The shortcomings of robotic systems are examined and innovative solutions are offered.

CONCLUSIONS

This study shows the advantages and disadvantages of the robotic surgical approach to the mesial temporal region via the supracerebellar transtentorial route. Robotic surgical systems can play a major role in neurosurgical practices with the tools designed and the innovative solutions determined in this study. Nevertheless, further research and development of these systems and related instruments are necessary to ensure their wider implementation in neurosurgery.

Duplication of the pituitary gland and basilar artery, with multiple midline fusion defects and craniofacial anomalies

Duplication of the pituitary gland (DPG) is a phenomenon with no clear syndromic association. This case adds to the literature as a DPG-plus syndrome patient with multiple fusion defects of unknown etiology, fetal risk factors of first trimester tobacco usage and intrauterine drug exposure. An 8-month old female presented with noisy breathing, poor feeding, cleft palate, seizures and failure to thrive. MRI scan revealed duplicate pituitary gland, tubomammillary fusion, absent cleavage of brainstem and superior cerebellar peduncles, and cervical spinal malformations. We performed an airway evaluation, with a glossomandibulopexy for glossoptosis, and a primary palate repair.

Vascularization of the Subthalamic Nucleus: Highlighting the Significance of the Premamillary Artery

BACKGROUND

The need for a better understanding of the subthalamic nucleus (STN)'s vascular anatomy is still evident because revealing its vascular supply may increase insight in the pathogenesis of related disorders, such as STN ischemia. The mechanisms under motor, behavioral, and cognitive changes following deep brain stimulation treatment may also be explained by its pattern of vascularization. The primary goal of this study was to delineate the vascularization of the STN and highlight the predominant perforating arteries supplying its territory.

METHODS

Fiber dissections were performed with the modified Klingler technique under 6-40× magnification by preserving all vascular structures.

RESULTS

The thalamic and subthalamic regions were dissected from medial to lateral in silicone-injected cadavers. The STN was revealed as a biconvex-shaped structure surrounded by dense inferolateral bundles of myelinated fibers, the zona incerta, bordering the superolateral portion of the red nucleus. The ventral limit of the STN was the substantia nigra, and the internal capsule traversed from its inferior to anterolateral side. The premamillary artery, a large perforator arising from the posterior communicating artery, constantly supplied the STN and was followed proximally along the anterior third ventricular floor toward its origin. The premamillary artery was found to be one of the posterior perforators of the posterior communicating artery in all hemispheres.

CONCLUSIONS

The 3-dimensional microsurgical anatomy of the deep-seated STN region is complex, and the additional knowledge on its vascularization should improve our understanding of its surgical anatomy.

Anatomic Investigation of the Trajectory for Stereotactic Laser Amygdalohippocampectomy

BACKGROUND

Magnetic resonance imaging-guided laser interstitial thermal therapy (LITT) has emerged as a promising treatment for mesial temporal lobe epilepsy. Surgeons must understand the relevant anatomy that is traversed by the catheter and affected by ablation.

OBJECTIVE

To study the anatomic structures crossed by the LITT catheter until it reaches the amygdala.

METHODS

Three human cadaveric heads were implanted with catheters using a frameless stereotactic technique. The Visualase® system (Medtronic, Dublin, Ireland) was utilized to ablate along the trajectory. Coronal and oblique axial slices were created. Fiber tract dissections were performed in a lateral-medial and inferior-superior scheme. Magnetic resonance tractography was acquired to illustrate the tracts dissected.

RESULTS

Entry points occurred within 4 cm of the transverse and sagittal sinus, inferior to the lambdoid suture. The cortex of the inferior occipital gyrus was crossed in the region of the transverse occipital sulcus. The vertical occipital fasciculus was crossed en route to passing through the optic radiations. The catheter crossed through or inferior to the optic radiations before piercing the parahippocampal gyrus at about 4 cm from the skull. The catheter entered the hippocampus as it pierced the superior margin of the parahippocampus at 6 cm. The catheter entered the head of the hippocampus to lie inferolateral to the amygdala in the last centimeter of the trajectory.

CONCLUSION

Understanding the anatomic principles of LITT catheter trajectories will improve the ability to perform this procedure. The current study is the first to examine the anatomy of this trajectory and will serve as the basis for future studies.

Microneuroanatomy of the Anterior Frontal Laser Trajectory to the Insula

BACKGROUND

Magnetic resonance imaging-guided laser interstitial thermal therapy (LITT) is an emerging minimally invasive procedure for the treatment of deep intracranial lesions. Insular lesions are challenging to treat because of the risk of damaging important surrounding structures. The precise knowledge of the neural structures that are at risk along the trajectory and during the ablation is essential to reduce associated complications. This study aims to describe the relevant anatomy of the anterior frontal LITT trajectory to the insular region by using sectional anatomy and fiber dissection technique.

METHODS

Three silicone-injected cadaveric heads were used to implant laser catheters bilaterally to the insular region by using a frameless stereotactic technique from a frontal approach. Sections were cut in both the oblique axial plane parallel to the trajectory and in the coronal plane. White matter fiber dissections were used to establish the tracts related to the laser trajectory from lateral to medial and medial to lateral.

RESULTS

Supraorbital regions were selected as entry points. After crossing the frontal bone, the track intersected the inferior frontal lobe. The catheter was illustrated reaching the insular region medial to the inferior fronto-occipital fasciculus and insular cortex, and superior to the uncinate fasciculus. The uncinate fasciculus, extreme capsule, claustrum, external capsule, and putamen were traversed, preserving the major vascular structures.

CONCLUSIONS

Independent of the insular area treated, an understanding of the neuroanatomy related to the anterior frontal laser trajectory is essential to improve the ability to perform LITT of this challenging region.

Functional Reorganization in the Primary Somatosensory Cortex of Rat Following Hind-Paw Amputation: A Study of Functional Imaging with 1.5 Tesla MRI

AIM

To learn how rat primary somatosensory cortex (pSSC) responses to the loss of inputs from hind-paw, using fMRI of an inferior magnetic power (1.5 Tesla) with special designed high-powered rat coil.

MATERIAL AND METHODS

Ten adult male Sprague-Dawley rats were enrolled in this study. The rats were anesthetized with ketamine injection. Xylazine was intraperitoneally injected for analgesia and muscle relaxation with careful maintenance of spontaneous respiration. Either right or left hind-paws were amputated under aseptic conditions according to predefined random allocation of the rats. A 12-channel rat surface coil developed for proper image resolution in 1.5 Tesla MR was used. Functional magnetic resonance imaging was obtained before hind-paw amputation; 2, 15 and 30 days after the amputation.

RESULTS

Activation signals were detected in 5 rats' contralateral pSSC before the hind-paw amputation with regression and cessation of the signal after the amputation. Signal re-appeared in the contralateral pSSC of only one rat (rat 9) 30 days after the amputation.

CONCLUSION

This study showed that functional plasticity might occur in the pSSC following hind-paw amputation of rats. Further studies are necessary to understand the true nature of the plasticity observed in pSSC, with new and novel measurement techniques on cellular basis rather than gross anatomical one.

Effect of chitosan on sealer penetration into the dentinal tubules

Objective

The objective of this study is to compare the effectiveness of final irrigation with chitosan, ethylenediaminetetraacetic acid (EDTA), and citric acid (CA) on a resin-based sealer (AH plus sealer [Dentsply DeTrey, Konstanz, Germany]) penetration into dentinal tubules using confocal laser scanning microscopy.

Materials and Methods

Seventy recently extracted human mandibular premolars were instrumented and irrigated with sodium hypochlorite (NaOCl), then divided into four groups according to the final irrigation regimen used: (1) the EDTA group: 17% EDTA + 2.5% NaOCl, (2) the CA group: 10% CA + 2.5% NaOCl, (3) the chitosan group: 0.2% chitosan + 2.5% NaOCl, and (4) the control group: 2.5% NaOCl. All teeth were obturated using the cold lateral condensation technique with gutta-percha and AH Plus sealer labeled with fluorescent dye. The apical 2 mm of specimen was discarded, and slices were obtained for apical, middle, and coronal thirds of the root with 1 mm intervals. Maximum, mean, and percentage of sealer penetration (SP) inside tubules were measured using confocal laser scanning microscopy.

Results

The percentage of SP was significantly higher in chitosan, EDTA, and CA group than control group for coronal thirds (P < 0.05), whereas there was no significant difference among all groups for middle and apical thirds. Chitosan and EDTA showed increased mean values of SP depth for middle thirds (P < 0.05). In all sections, the maximum depth of SP was significantly lower in EDTA group than other groups (P < 0.05).

Conclusions

Chitosan, EDTA, and CA significantly improved the percentage of SP for coronal thirds.

Traumatic Rupture of Giant Pulmonary Hydatid Cyst in a Child

Introduction

Trauma as a cause of hydatid cyst rupture leads to various clinical conditions, especially in children. Current literatures regarding the clinical presentation and management of such patients are rare.

Case report

A 14-year-old child was admitted with chest pain and dyspnoea due to blunt thoracic trauma after falling off a bicycle. Chest computed tomography showed right hydropneumothorax and cystic cavity. After chest tube insertion, massive air leak was observed from the tube. Cystotomy and capitonnage were performed on the right lower lobe via a posterolateral thoracotomy. He was discharged from the hospital in good condition.

Conclusion

Ruptured hydatid cysts into the pleura are difficult to diagnose radiologically. It can be misdiagnosed radiologically as empyema or hydrothorax. In undetermined cases, all the findings may be suggestive but not diagnostic. Operation must be performed early for exploration when the condition is suspected. High complication rate has been found in children who were operated late.

Microsurgical and endoscopic approaches to the pulvinar

OBJECTIVE

Approaches to the pulvinar remain challenging because of the depth of the target, surrounding critical neural structures, and complicated arterial and venous relationships. The purpose of this study was to compare the surgical approaches to different parts of the pulvinar and to examine the efficacy of the endoscope as an adjunct to the operating microscope in this area.

METHODS

The pulvinar was examined in 6 formalin-fixed human cadaveric heads through 5 approaches: 4 above and 1 below the tentorium. Each approach was performed using both the surgical microscope and 0° or 45° rigid endoscopes.

RESULTS

The pulvinar has a lateral ventricular and a medial cisternal surface that are separated by the fornix and the choroidal fissure, which wrap around the posterior surface of the pulvinar. The medial cisternal part of the pulvinar can be further divided into upper and lower parts. The superior parietal lobule approach is suitable for lesions in the upper ventricular and cisternal parts. Interhemispheric precuneus and posterior transcallosal approaches are suitable for lesions in the part of the pulvinar forming the anterior wall of the atrium and adjacent cisternal part. The posterior interhemispheric transtentorial approach is suitable for lesions in the lower cisternal part and the supracerebellar infratentorial approach is suitable for lesions in the inferior and medial cisternal parts.

The microscope provided satisfactory views of the ventricular and cisternal surfaces of the pulvinar and adjacent neural and vascular structures. The endoscope provided multi-angled and wider views of the pulvinar and adjacent structures.

CONCLUSIONS

A combination of endoscopic and microsurgical techniques allows optimal exposure of the pulvinar.

A New Less Invasive Technique for Multiple-Level Spontaneous Spinal Epidural Hematomas: Wash-and-Go Technique

Aim Spinal epidural hematomas are rare entity in neurosurgery practice. Most of them are spontaneous due to anticoagulant therapy and called spontaneous spinal epidural hematomas (SSEHs). Laminectomy or hemilaminectomy for affected levels is still the first choice in the operative treatment of an SSEH. We describe a new less invasive surgical technique, performing single-level laminectomy and washing with 0.9% sodium chloride through a thin soft catheter for a 12-level thoracic-cervical SSEH in a patient under anticoagulant therapy. Patient and Operative Technique A 55-year-old woman was brought to the emergency department with a rapid onset of pain in her upper back and both legs with weakness of her lower extremities. An urgent magnetic resonance imaging (MRI) of the whole spine showed a SEH. During the operation, after T2 laminectomy, a thin soft catheter was epidurally placed under the T1 lamina and gently pushed forward rostrally. Then continuous saline irrigation was utilized and aspiration made via the catheter to wash out the hematoma. Drainage of blood was observed. The procedure was performed for 15 minutes. Then the catheter was epidurally placed under the T3 lamina, and the procedure for the hematoma in the lower segment was repeated. Decompression of spinal cord and nerve roots was observed. Result Postoperative early MRI of the thoracic-cervical spine showed gross total evacuation of the SEH. Accordingly, the patient's muscle strength improved. Conclusion Although multiple laminectomy or hemilaminectomy for affected levels to evacuate the hematoma and decompress the spinal cord is the main choice of surgical treatment, single-level laminectomy and irrigation plus aspiration via a thin soft catheter can be performed successfully with good results in SSEH.

Outcome of surgical treatment of hippocampal sclerosis from relatively new epilepsy surgery center

BACKGROUND

Surgery is apparently superior to prolonged medical therapy in therapy of efficacy and safety for mesial temporal lobe epilepsies. We ‑ as a new center ‑ presented outcome results and possible outcome predictors of 50 consecutive patients with hippocampal sclerosis underwent resective epilepsy surgery.

METHODS

Between 2006 and 2011, fifty patients with intractable mesial temporal lobe epilepsy due to hippocampal sclerosis underwent anterior temporal lobectomy and they were followed-up at least 1 year postoperatively. Detailed neuropsychological tests, video-electroencephalography monitoring and magnetic resonance imaging with epilepsy protocol were obtained for all patients. Standard anteromedial temporal lobectomy was performed. Modified Engel and ILAE classifications were used for seizure outcome. All morbidities were recorded. Demographic variables, diagnostic tests and early postoperative outcome were analyzed for possible predictors of the ultimate seizure outcome.

RESULTS

Fifty patients were evaluated. The mean follow-up duration was 47,1 month (range, 12-75 months). The favorable outcome at 1 year was 90% and 82% according to Engel and ILAE classifications respectively. These rates were almost same at the end of follow-up period (92% and 82% respectively). The completely seizure free rate at one year was 80% and decreased to 68% at the end of the follow-up. There was no mortality. Morbidity rate was 10% and none of them was permanent. Triple concordance of the noninvasive tests (neuropsychological tests, video- electroencephalography monitoring and magnetic resonance imaging) and favorable seizure outcome at the first year were predictors of the ultimate seizure outcome (P=0.01 and P=0.04 respectively).

CONCLUSIONS

Our findings demonstrated that anteromedial temporal lobectomy is a safe and effective treatment method in well-chosen patients with hippocampal sclerosis. This surgical procedure can be performed with a low rate of morbidity even in relatively new epilepsy surgery center.

Fiber Tracts of the Medial and Inferior Surfaces of the Cerebrum

OBJECTIVE

Fiber dissection studies of the cerebrum have focused on the lateral surface. No comparable detailed studies have been done on the medial and inferior surfaces. The object of this study was to examine the fiber tracts, cortical, and subcortical structures of the medial and inferior aspects of the brain important in planning operative approaches along the interhemispheric fissure, parafalcine area, and basal surfaces of the cerebrum.

METHODS

Twenty formalin-fixed human hemispheres (10 brains) were examined by fiber dissection technique under ×6-×40 magnifications.

RESULTS

The superior longitudinal fasciculus I, cingulum, inferior longitudinal fasciculus, uncinate fasciculus, optic radiations, tapetum, and callosal fibers were dissected step by step from medial to lateral, exposing the nucleus accumbens, subthalamic nucleus, red nucleus, and central midline structures (fornix, stria medullaris, and stria terminalis). Finally, the central core structures were dissected from medial to lateral.

CONCLUSIONS

Understanding the fiber network underlying the medial and inferior aspects of the brain is important in surgical planning for approaches along the interhemispheric fissure, parafalcine area, and basal surfaces of the cerebrum.

The double massa intermedia

Background:

To describe the rare finding of a double massa intermedia (MI). Typically, the MI (interthalamic adhesion) is a single bridge of gray matter connecting the medial surfaces of the thalami.

Methods:

Twelve formalin- and alcohol-fixed human third ventricles were examined from superior to inferior by fiber dissection technique under ×6 to ×40 magnifications and with the endoscope.

Results:

In all hemispheres, the anterior and posterior commissure were defined. The MI, which bridges the medial surfaces of the thalami, was defined in all hemispheres. In one hemisphere, there was a second bridge between the thalami, located posteroinferior to the common MI. Endoscopic view confirmed that there was a second MI in this specimen. The MI usually traverses the third ventricle posterior to the foramen of Monro and connects the paired thalami. The MI is an important landmark during endoscopic and microscopic surgeries of the third ventricle. Although a double MI is very rare, surgeons should be aware of the possibility in their surgical planning.

Conclusion:

The surgeon should be aware of the possibility of a double MI to avoid confusion during third ventricle surgery.

Diffuse, encasing lymphangioma of the supraglottis

BACKGROUND

Lymphangioma of the head and neck is considered a rare congenital tumor with the vast majority presenting before two years of age. Surgical excision and sclerosing therapy using OK-432 are recognized as effective treatment options for the majority of these lesions; however, treatment options of laryngeal lesions are less straightforward due to the risk of airway compromise and the desire to maintain the integrity of a functional larynx. We present the case of a four month old male who presented with chief complaint of inspiratory stridor after a single episode of pneumonia. His clinical presentation, flexible fiberoptic laryngoscopic examination, and operative evaluation were consistent with a lymphangioma completely encasing the epiglottis and arytenoids and isolated to the supraglottis. This report outlines our approach to workup and treatment of this rare lesion.

METHOD

Case report of presentation, diagnosis and treatment is presented.

RESULTS

A four-month old male presented to ENT clinic with inspiratory stridor, worsened with crying, without frank respiratory distress. History and initial examination was consistent with airway obstruction. Flexible fiberoptic laryngoscopy showed laryngomalacia as well as diffuse and symmetric supraglottic edema. Surgical evaluation identified edema limited to the supraglottis, notably along the ventral surface of the epiglottis and dorsal surface of bilateral arytenoids. Biopsies were taken and immunohistochemical staining was performed with strong positivity for D2-40 and CD31, supporting the diagnosis of isolated lymphangioma of the supraglottis. Treatment was performed through multiple point spot welding with a fiber equipped CO2 LASER (OmniGuide TM) at 5 watt continuous power.

CONCLUSION

Isolated supraglottic lymphangioma was diagnosed via direct laryngoscopy, with pathologic and immunohistochemical confirmation. Carbon dioxide laser spot welding technique was used with excellent clinical improvement in stridor. Clinical improvement is sustained after 6 months follow-up.

Bullous skin reaction seen after extravasation of calcium gluconate

Intravenous (IV) calcium is usually given to temporarily treat the effects of hyperkalaemia on muscle and heart. When extravasation of a calcium gluconate infusion occurs, there may be rapid and marked swelling and erythema, with signs of soft-tissue necrosis or infection, and ensuing extensive local calcification, called calcinosis cutis. We report a 26-year-old woman who was hospitalized for exacerbation of acute intermittent porphyria. She had a history of hypertension and chronic renal failure. On the second day of her hospitalization, she developed hyperpotassaemia (6.7 mEq/L potassium; normal range 3.5-5 mEq/L). She was given an IV infusion of 10 mL calcium gluconate into the left dorsal pedal vein. Bullous skin reactions occurred in the infusion area nearly 2 h after administration. The patient's leg was elevated and the lesions cleaned with 0.9% saline. By day 9 of hospitalization, the lesions had markedly regressed. Several drugs have been associated with dermoepidermal blistering as an adverse drug reaction, but there is only one existing report in the literature about this side-effect associated with calcium gluconate. Clinicians should be alert to the possibility of bullous skin reactions, which may be a predictor of extravasation and necrosis, when treating patients with IV calcium gluconate.

The association of oxidative stress and nasal polyposis

Many diseases are linked to damage from reactive oxygen species that occurs from an imbalance between reactive oxygen species and antioxidants, a condition called oxidative stress. Nasal polyposis is considered to be an inflammatory condition in nasal and paranasal sinus cavities and its aetiology is still unclear. There are very few data on epithelial changes in nasal polyposis and their relationship with free radical damage. Malondialdehyde as a major end-product of lipid peroxidation, and superoxide dismutase and nitric oxide as antioxidants play important roles in oxidative stress. In this study, the concentrations of malondialdehyde, superoxide dismutase and nitric oxide were compared in normal and nasal polyposis-affected tissue samples. Malondialdehyde levels were significantly higher, and superoxide dismutase and nitric oxide levels were significantly lower in patients with nasal polyposis compared with the control group. This study demonstrates that there is a strong relationship between oxidative stress and the pathogenesis of nasal polyposis.

Effectiveness of transmeatal low power laser irradiation for chronic tinnitus

Objective:

To evaluate effectiveness of 5 mW laser irradiation in the treatment of chronic tinnitus.

Study design:

Prospective, randomised, double-blind study.

Methods:

This investigation included 66 ears in 45 patients with chronic unilateral or bilateral tinnitus. A 5 mW laser with a wavelength of 650 nm, or placebo laser, was applied transmeatally for 15 minutes, once daily for a week. A questionnaire was administered which asked patients to score their symptoms on a five-point scale, before and two weeks after laser irradiation. A decrease of one scale point, regarding the loudness, duration and degree of annoyance of tinnitus, was accepted to represent an improvement.

Results:

The loudness, duration and degree of annoyance of tinnitus were improved, respectively, in up to 48.8, 57.7 and 55.5 per cent of the patients in the active laser group. No significant improvement was observed in the placebo laser group.

Conclusion:

Transmeatal, low power (5 mW) laser irradiation was found to be useful for the treatment of chronic tinnitus.