Comparative Optics of the Surgical Microscope and Rigid Endoscopes in Neurosurgery.

This chapter is intended to provide a brief overview of the optics of surgical microscopes and rigid endoscopes, with the aim of providing the reader with the principles dictating the nature of surgical visualization when either of the visual control systems is used. It is not by any means geared toward elaborating on the detailed optical physics of these systems, which is beyond the scope and objective of this chapter.

Fully Endoscopic Nontubular Retractor Approach for Intraaxial Tumors.

BACKGROUND: Fully endoscopic or endoscope-controlled approaches are essentially keyhole approaches in which rigid endoscopes are the sole visualization tools used during the whole procedure. At the early attempts of endoscope-assisted cranial surgery, it was noted that rigid endoscopes enabled overcoming the problem of suboptimal visualization when small exposures are used. The technical specifications and design of the currently available rigid endoscopes are associated with a group of unique features that define the endoscopic view and lay the basis for its superiority over the microscopic view during brain surgery. Fully endoscopic resection of intraparenchymal brain tumors is a minimally invasive approach that is not routinely practiced by neurosurgeons, with a few major series published so far. Unfamiliarity with the technique, steep learning curve, and concerns about inadequate exposure and decreased visibility may explain this fact. The majority of the purely endoscopic resections for intraparenchymal brain lesions are performed nowadays through tubular retractor systems. In very limited instances, however, the fully endoscopic technique is performed without tubular retractors. In this chapter, we elaborate on the surgical technique and nuances of the fully endoscopic nontubular retractor approach for intraaxial tumors. METHODS: From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, and operative charts and videos of cases undergoing fully endoscopic excision for intraaxial brain tumors were retrieved and analyzed. The pertinent literature was also reviewed. RESULTS: The surgical technique of the fully endoscopic nontubular retractor approach for intraaxial tumors was formulated. CONCLUSION: The endoscopic technique has many advantages over the conventional procedures. In our hands, the technique has proven to be feasible, efficient, and minimally invasive with excellent results.

Fully Endoscopic Retrosigmoid Approach for Cerebellopontine Angle Tumors.

BACKGROUND: Fully endoscopic or endoscope-controlled approaches are essentially keyhole approaches in which rigid endoscopes are the sole visualization tools used during the whole procedure. At the early attempts of endoscope-assisted cranial surgery, it was noted that rigid endoscopes enabled overcoming the problem of suboptimal visualization when small exposures are used. The technical specifications and design of the currently available rigid endoscopes are associated with a group of unique features that define the endoscopic view and lay the basis for its superiority over the microscopic view during brain surgery. Fully endoscopic retrosigmoid approach for cerebellopontine angle tumors is a minimally invasive approach that is not routinely practiced by neurosurgeons, with few series published so far. Unfamiliarity with the technique, steep learning curve, and concerns about inadequate exposure, neurovascular injury, and decreased visibility may explain this fact. In this chapter we elaborate on the surgical technique and nuances of the fully endoscopic retrosigmoid approach and present an overview of the published series. METHODS: From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, operative charts, and videos of cases undergoing fully endoscopic retrosigmoid approach for cerebellopontine angle tumors were retrieved and analyzed. The pertinent literature was also reviewed. RESULTS: The surgical technique of the fully endoscopic retrosigmoid approach was formulated. CONCLUSION: The endoscopic technique has many advantages over the conventional procedures. In our hands, the technique has proven to be feasible, efficient, and minimally invasive with excellent results.

Fully Endoscopic Resection of Frontal Osteomas.

BACKGROUND: Osteomas are the most common primary bone tumors of the calvaria, with an incidence of less than 0.5%. In skull vault osteomas, the exostotic form that grows from the outer table is more common than the enostotic ones which arise from the inner table and grow intracranially. Osteomas of the forehead are very noticeable and disfiguring; patients usually seek medical advice for cosmetic reasons. Forehead osteomas were traditionally excised via either a direct incision over the lesion using the naturally occurring creases or a conventional bicoronal flap. More recently, endoscopic approaches for excision of forehead osteomas were introduced. The results were very encouraging and the technique was adopted by many groups worldwide yet with many technical variations. In this chapter we elaborate on the surgical technique and nuances of the fully endoscopic resection of frontal osteomas. METHODS: From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, operative charts, and videos of cases of forehead osteomas were retrieved and analyzed. The pertinent literature was also reviewed. RESULTS: The surgical technique of the fully endoscopic resection of frontal osteomas was formulated. CONCLUSION: The endoscopic technique has many advantages over the conventional procedures. In our hands, the technique has proven to be less time-consuming, efficient, and minimally invasive with excellent cosmetic results.

Fully Endoscopic Supraorbital Approach for Anterior Cranial Base Meningiomas.

BACKGROUND: Anterior cranial base meningiomas include those meningiomas originating from the tuberculum sellae, the planum sphenoidale, or the olfactory groove, with surgical excision being the main treatment modality for these tumors. Conventional microscopic and endoscope-assisted versions of the supraorbital keyhole approach via an eyebrow incision emerged into minimally invasive options that are frequently utilized nowadays for treating these tumors. At the early attempts of endoscope-assisted cranial surgery, it was noted that rigid endoscopes enabled overcoming the problem of suboptimal visualization when small exposures are used. The technical specifications and design of the currently available rigid endoscopes are associated with a group of unique features that define the endoscopic view and lay the basis for its superiority over the microscopic view during brain surgery. Notwithstanding, the fully endoscopic or endoscope-controlled version of the supraorbital keyhole approach is not routinely practiced by neurosurgeons, with few series published so far. In this chapter we elaborate on the surgical technique and nuances of the fully endoscopic supraorbital approach for anterior cranial base meningiomas. METHODS: From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, operative charts, and videos of cases undergoing fully endoscopic excision of anterior cranial base meningiomas via supraorbital approach were retrieved and analyzed. The pertinent literature was also reviewed. RESULTS: The surgical technique of the fully endoscopic supraorbital approach for anterior cranial base meningiomas was formulated. CONCLUSION: The fully endoscopic supraorbital approach for anterior cranial base meningiomas has many advantages over the conventional procedures. In our hands, the technique has proven to be feasible, efficient, and minimally invasive with excellent results.

Pseudotumoral Encephalic Schistosomiasis: A Literature Review.

Pseudotumoral encephalic schistosomiasis (PES) is the chronic form of cerebral neuroschistosomiasis, and is rarely encountered in clinical practice. Clinically, PES closely resembles other intracranial space-occupying lesions including brain tumors. Laboratory investigations are usually inconclusive, and neuroradiologic findings are frequently reported as non-specific. Such diagnostic difficulties may result in delayed diagnosis and treatment. Across the literature, there is a paucity of information about and controversy over many aspects of the disease. Particularly, inconsistent magnetic resonance imaging (MRI) findings, a wide variation of medical treatment protocols, lacking consensus regarding the indications of surgery, and undetermined information regarding the impact of the extent of resection on prognosis. We herein review the pertinent literature with the aim of providing focused information regarding the pathogenesis of PES, its currently identified more distinctive neuroimaging features, and the indications and extent of surgery in light of the state-of-the-art operative neurosurgical practice. A distinctive multinodular arborizing pattern of PES lesions can often be observed on MRI in patients with PES. Praziquantel is considered by many authors to be the drug of choice in all cases, and seems to be effective at variable dose regimens. Although lesion excision utilizing current technology is generally safe, the indications and extent of surgery are still undetermined and should be decided on a case-by-case basis. Multicenter collaborative research is further needed to fill the existing gaps in the current knowledge on PES.

Endoscopic Endonasal Surgery for Uncommon Pathologies of the Sellar and Parasellar Regions.

Endoscopic skull base surgery has become an integral part of the present neurosurgical armamentarium. The pioneering efforts in which the purely endoscopic transsphenoidal approach was introduced have triggered a growing tide of using the endoscopic endonasal procedures for a large variety of skull base lesions. Because of their anatomical peculiarities, lesions of the sellar and parasellar regions lend themselves very well to the endoscopic endonasal approaches. Apart from the common pathological entities, many other less frequent pathologies are encountered in the sellar and parasellar area. In this chapter, we review the surgical technique of the endoscopic endonasal transsphenoidal approach and its extensions applied to a variety of rare and uncommon pathological entities involving the sella turcica and clivus. An overview of these pathological entities is also presented and exemplified.

Purely endoscopic and endoscope-assisted approaches to lesions of the third ventricle in pediatric age-a technical collection.

BACKGROUND: One of the main difficulties in third ventricle surgery is its deep and central location within the brain, surrounded by many eloquent neurovascular structures. Such anatomical environment obviously makes it very hard to safely approach and excise lesions in there. METHODS: The introduction of the surgical microscope into the neurosurgical field undoubtedly played an important and pivotal role in improving the surgical results and increasing the safety of operations in and around the third ventricle. Although the surgical microscope remained the gold standard of intraoperative visualization for many decades, the advent of endoscopes revolutionized surgery of the third ventricle. Neuroendoscopic procedures for lesions of the third ventricle encompass a greatly variable array of endochannel, endoscope-assisted and endoscope-controlled techniques. CONCLUSION: In this collection on purely endoscopic and endoscope-assisted approaches to lesions of the third ventricle in pediatric age, the readership is presented with a selected group of these operations performed by experts in the field, shedding light mainly on their technical aspects and surgical pearls. The text description in each article is supplemented by a surgical video.

Carbon disulfide removal from gasoline fraction using zinc-carbon composite synthesized using microwave-assisted homogenous precipitation.

Carbon disulfide (CS2) is one of the sulfur components that are naturally present in petroleum fractions. Its presence causes corrosion issues in the fuel facilities and deactivates the catalysts in the petrochemical processes. It is a hazardous component that negatively impacts the environment and public health due to its toxicity. This study used zinc-carbon (ZC) composite as a CS2 adsorbent from the gasoline fraction model component. The carbon is derived from date stone biomass. The ZC composite was prepared via a homogenous precipitation process by urea hydrolysis. The physicochemical properties of the prepared adsorbent are characterized using different techniques. The results confirm the loading of zinc oxide/hydroxide carbonate and urea-derived species on the carbon surface. The results were compared by the parent samples, raw carbon, and zinc hydroxide prepared by conventional and homogeneous precipitation. The CS2 adsorption process was performed using a batch system at atmospheric pressure. The effects of adsorbent dosage and adsorption temperatures have been examined. The results indicate that ZC has the highest CS2 adsorption capacity (124.3 mg.g-1 at 30 °C) compared to the parent adsorbents and the previously reported data. The kinetics and thermodynamic calculation results indicate the spontaneity and feasibility of the CS2 adsorption process.

Endoscopic trans-septal interforniceal approach for excision of colloid cysts of the third ventricle using the rotational technique.

Colloid cysts of the third ventricle are benign intracranial lesions that account for 0.5 to 2% of all brain tumors and are even rarer in pediatric population. Dandy was the first to successfully excise a colloid cyst of the third ventricle via a transcortical transventricular approach in 1921. For several decades to follow, the transcortical transventricular and transcallosal microsurgical approaches remained the cornerstone of surgical management of these lesions. With time and refinements in endoscopic equipment and techniques, endoscopic resection of colloid cysts evolved into a currently well-established and appealing minimally invasive alternative to microsurgery. Endoscopic endochannel techniques for colloid cysts of the third ventricle may either be transforaminal or trans-septal interforniceal, depending on the pathoanatomical features of the colloid cyst and its relation to the juxtaposed anatomical structures. The endoscopic trans-septal interforniceal approach is required to access the rare subset of colloid cysts that extend superior to the roof of the third ventricle between the two fornices insinuating themselves between the leaflets of the septum pellucidum. In this article, the surgical technique of the endochannel endoscopic trans-septal interforniceal approach is elaborated upon. A representative case is presented along with an operative video.

Purely Endoscopic Retrosigmoid Approach for Excision of a Large Multicystic Hypoglossal Schwannoma.

Hypoglossal schwannomas are rare tumors that account for 1%-7% of all nonvestibular intracranial schwannomas. They commonly affect middle-aged females.1 They can be completely intracranial (type A), intracranial/extracranial (type B), or completely extracranial (type C).2 Presenting symptoms include hypoglossal nerve dysfunction, additional lower cranial neuropathies and, rarely, increased intracranial pressure. Patients with the rare extracranial tumors most commonly present with an asymptomatic mass in the neck or submandibular region.3 Treatment options include observation in small asymptomatic tumors and surgical excision in large tumors with mass effect. In tumors that require treatment and are within the size range, radiosurgery should be considered.1 In this operative Video 1, the patient is a 45-year-old woman who presented with a 1-year history of progressive headaches, right-sided retroauricular pain, unsteady gait, hoarseness of voice, and dysphagia. Neurologic examination revealed right cranial nerves IX to XII palsies, pyramidal manifestations, and right cerebellar ataxia. Imaging findings were consistent with large multicystic hypoglossal schwannoma. A purely endoscopic retrosigmoid approach was performed for excision of the lesion. A 4K rigid endoscope offers a highly illuminated and extremely detailed views of the tumor and the anatomic structures within the surgical field, adding greatly to the safety of surgery. Furthermore, the panoramic view and large depth of focus of the endoscope result in greater ease of orientation within the surgical field with significant reduction of the number of times the viewing angle needs to be changed during the procedure.

Endoscope-controlled extended supraorbital keyhole approach through a modified eyebrow incision for a large dural-based solitary fibrous tumor of the frontal convexity: A technical note.

Background: The extended supraorbital approach through a modified eyebrow incision is a minimally invasive approach that has been recently described. It entails a lateral extension of the skin incision beyond the lateral end of the eyebrow and allows exposure of the proximal sylvian fissure with a superior degree of surgical freedom in the middle fossa and the parasellar region. In this technical note, we describe an endoscope-controlled extended supraorbital keyhole approach with modified eyebrow incision for excision of a large dural-based solitary fibrous tumor of the left frontal convexity. Methods: An endoscope-controlled extended supraorbital keyhole approach with modified eyebrow incision was performed to excise a large extra-axial mass attached to the dura of the left frontal convexity and extends from the superior temporal line up to the midline in a 34-year-old male patient presented with 1-year history of headache, dizziness, and blurred vision. Results: The patient had an uneventful postoperative course with gross total excision of the lesion and satisfying cosmetic appearance. Histopathological examination revealed a Grade 1 solitary fibrous tumor. Conclusion: We demonstrated the feasibility of the endoscope-controlled extended supraorbital keyhole approach through a modified eyebrow incision for excision of tumors that abut the inner table of the frontal calvarial bone, extend highly above the skull base level, or extend medially reaching the midline. The approach is very versatile and allows a great exposure for a category of lesions deemed not perfectly suitable for the classic supraorbital keyhole approach.

Persisting embryonal infundibular recess (PEIR) and transsphenoidal-transsellar encephaloceles: distinct entities or constituents of one continuum?

Persisting embryonal infundibular recess (PEIR) is a very rare anomaly of the floor of the third ventricle in which the embryonic morphology of the infundibular recess (IR) persists. The exact underlying mechanism of development of PEIR is unknown, and the anomaly has been reported as an isolated finding or in association with other conditions. On the other hand, trans-sphenoidal encephaloceles are the rarest form of basal encephaloceles. The trans-sphenoidal trans-sellar encephalocele (TSE) is the least common variant in which the pituitary gland, pituitary stalk, optic pathways, parts of the third ventricle and IR may be present within the encephalocele. We recently treated one patient with TSE. Based on the observed morphological similarity of the IR in our patient and in the published cases of PEIR, we reviewed the literature in order to validate the hypothesis that PEIR and TSE may possibly belong to one spectrum of malformations. Across the published reports, the morphology of the IR in TSE is very closely similar to PEIR. Moreover, radiological, patho-anatomical, and embryological evidence is in support to our hypothesis that PEIR and TSE are most likely the two extremes of the same continuum of malformations.

Sustainable ecofriendly recruitment of bioethanol fermentation lignocellulosic spent waste biomass for the safe reuse and discharge of petroleum production produced water via biosorption and solid biofuel production.

Sustainable lignocellulosic spent waste rice straw (SWRS) from bioethanol production inventively applied in this study to valorize petroleum production produced water (PPPW). SWRS expressed efficient pollutant removal over a wide range of petroleum concentration, temperature, pH, salinity, and mixing rate reaching approximately 217 mg/g, within four hours contact time. Kinetic studies revealed a pseudo-second-order chemisorption process with a boundary layer control and 16.97 kJ/mol activation energy where the intra-particle diffusion was not the only rate regulatory step. Thermodynamic studies revealed spontaneous, favorable, and endothermic adsorption, with a strong affinity between the SWRS and oil molecules. Biosorption mechanism studies proved the enrollment of SWRS components' lignin, cellulose, and hemicellulose in the oil uptake with the predominance of chemisorption over physisorption onto the rough and highly porous SWRS surface. A single-stage batch biosorption process was designed based on the best fitted Langmuir adsorption isotherm and applied on a real PPPW sample. The Egyptian standard limits for safe industrial effluents discharge into marine environment with a concomitant decrease in scale formation precursors were achieved recommending its safe reuse for enhanced oil recovery. Finally, for accomplishing zero-waste, SWRS disposed of PPPW treatment substantiated valorized solid biofuel with a sufficient calorific value 38.56 MJ/kg.

Coronavirus disease 2019 infection and pituitary apoplexy: A causal relation or just a coincidence? A case report and review of the literature.

BACKGROUND: Pituitary tumor apoplexy (PA) is an emergency condition caused by hemorrhage or infarction of the preexisting adenoma. Many factors are currently well-known to predispose to PA. However, during the period of coronavirus disease 2019 (COVID-19) pandemic, case reports of PA associated with COVID-19 infection have been sequentially published. To the best of our knowledge, four cases have been reported so far in the English literature. We herein report the fifth case of this association and review the pertinent literature. CASE DESCRIPTION: A 55-year-old male patient with confirmed COVID-19 infection presented by progressive decrease in visual acuity and oculomotor nerve palsy. His medical history is notable for diabetes mellitus, hypertension, and pituitary macroadenoma resection 11 years ago. He was on hormonal replacement therapy for panhypopituitarism that complicated the surgery. Previous magnetic resonance (MR) imaging studies were consistent with enlarging residual pituitary adenoma. During the current hospitalization, computed tomography revealed hyperdensity of the sellar and suprasellar areas. MR imaging revealed PA in a recurrent large adenoma. Endoscopic endonasal transsphenoidal resection was uneventfully undertaken with near total excision of the adenoma and partial improvement of visual loss and oculomotor palsy. Histopathological examination demonstrated classic features of PA. However, his chest condition progressed and he had to be transferred to COVID-19 intensive care unit in the referring hospital where he was intubated and put on mechanical ventilation. One week later, the patient unfortunately passed away due to complications of severe COVID-19 pneumonia. CONCLUSION: We report the fifth case of PA associated with COVID-19 infection. Based on our patient's clinical findings, review of the other reported cases, as well as the available literature, we put forth a multitude of pathophysiological mechanisms induced by COVID-19 that can possibly lead to the development of PA. In our opinion, the association between both conditions is not just a mere coincidence. Although the histopathological features of PA associated with COVID-19 are similar to PA induced by other etiologies, future research may disclose unique pathological fingerprints of COVID-19 virus that explains its capability of inducing PA.

Designing Dual-Effect Nanohybrids for Removing Heavy Metals and Different Kinds of Anions from the Natural Water.

In the present study, well-designed nanohybrids are used to act as effective dual-function adsorbents for removing both anions and heavy metals from natural water, at the same time. In this trend, Zn-Al LDHs and graphene oxide are applied to build up building blocks to produce a series of nanohybrids. These nanohybrids were characterized by X-ray diffraction, thermal analyses, Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning and transmission electron microscopy. These techniques confirmed that the prepared nanohybrids contained nanolayered structures with three-dimensional porous systems. These porous systems were identified by the nitrogen adsorption-desorption isotherms and water purification experiments. The obtained results indicated that these nanohybrids included suitable structures to act as dual function materials. The first function was achieved by removing more than 80% of both cadmium and lead from the natural water. The second function was accomplished by eliminating of 100% of hydrogen phosphate and bromide anions alongside with 80%-91% of sulfate, chloride, and fluoride anions. To conclude, these well-designed nanohybrids convert two-dimensional nanolayered structures to three-dimensional porous networks to work as dual-function materials for removing of heavy metals and different kinds of anions naturally found in the fresh tap water sample with no parameters optimization.

Effect of Sphenoid Sinus Pneumatization on the Surgical Windows for Extended Endoscopic Endonasal Transsphenoidal Surgery.

BACKGROUND: Little is known on the impact of the pattern and extent of pneumatization of the sphenoid sinus (SS) on the dimensions of the surgical windows used in extended endoscopic endonasal transsphenoidal approaches. We therefore investigated whether the distances between the 2 optic canals and between the paired paraclival carotid arteries are influenced by the pattern and extent of pneumatization of the SS. METHODS: One hundred high-resolution computed tomography scans from 47 adult female and 53 adult male patients were analyzed. The pattern of SS pneumatization was classified into conchal, presellar, and sellar types. Sellar-type sinuses were then classified according to a newer detailed classification system. Maximal anteroposterior (AP), transverse (TR), and craniocaudal diameters of the SS, interoptic distance at the limbus sphenoidale (IODL) and at the entrance of the optic canal (IODE) and the intercarotid distance between the paraclival carotids (ICD) were measured. A 2-tailed Mann-Whitney U test and Pearson correlation coefficient (R) were used for statistical analysis. A P value <0.05 was considered statistically significant. RESULTS: Positive correlation was found between IODL and both AP and TR diameters of the SS; between IODE and both AP and TR diameters of the SS; and between ICD and all diameters of the SS. The highest correlation for each of the IODL, IODE, and ICD was noted with the TR diameter of the SS. CONCLUSIONS: During the development of the SS, pneumatization progress likely exerts quantitative and direction-specific forces, which gradually increase the interoptic and intercarotid distances.