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.

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.

Endoscopic colloid cyst excision: surgical techniques and nuances.

BACKGROUND: Endoscopic excision of colloid cysts is currently well established as a minimally invasive and highly effective technique that is associated with less morbidity in comparison to microsurgical resection. METHODS: Operative charts and videos of patients undergoing endoscopic colloid cyst excision were retrieved from the senior author's database of endoscopic procedures and reviewed. This revealed nine trans-foraminal and three trans-septal procedures. Description of the surgical techniques was then formulated. CONCLUSIONS: Variation of the technique is based on the specific patho-anatomical features of the colloid cyst being resected. For the trans-foraminal approach, we think that the rotational technique is associated with a more complete removal of the cyst wall and consequently lower recurrence rate.

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.

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.

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.

Endoscopic Endonasal Excision of Large and Giant Pituitary Adenomas: Radiological and Intraoperative Correlates of the Extent of Resection.

BACKGROUND: Despite the superb visualization offered by the endoscopic endonasal transsphenoidal approach, the resection rates of large and giant pituitary adenomas have remained much lower than those of smaller macroadenomas. Various tumor characteristics can influence the extent of resection (EOR) and have been variably reported. Additional understanding of these factors is mandatory to improve the results. We analyzed the radiological and intraoperative tumor characteristics influencing the EOR in a cohort of patients with large and giant pituitary macroadenomas undergoing endoscopic endonasal transsphenoidal excision under our care. METHODS: Twenty-eight patients were included. Magnetic resonance images were retrospectively analyzed for pre- and postoperative tumor volumetric analysis; preoperative tumor volume calculation using the formula (A × B × C/2); preoperative radioanatomical characteristics, including tumor shape, radiological structure, contrast enhancement, and extension; and the EOR. Intraoperative data were retrieved and included. RESULTS: The preoperative calculated tumor volume was 38.14 ± 23.02 cm3 and the preoperative measured tumor volume was 50.345 ± 17.36 cm3. A statistically significant difference was found between the calculated and measured tumor volumes for the whole cohort and for tumors with a maximum diameter >3.9 cm. A statistically significant difference in the EOR was found at a volume threshold of 26.2 cm3. Large cysts, heterogeneous enhancement, Knosp grade ≤2, soft tumor consistency, and tumor hemorrhage were significantly associated with gross total resection. CONCLUSIONS: Volumetric analysis should replace 2-dimensional methods in determining the size of large and giant pituitary adenomas. Specific tumor characteristics were associated with the EOR and could help in predicting the EOR for these tumors.