Primary Sellar Abscesses: A Systematic Review and 2 Rare Observations.

BACKGROUND: Abscesses of the chiasmatic-sellar region are quite rare and are often a result of surgical intervention, trauma, or tumor growth. Primary abscesses are extremely rare and represent a group of abscesses the occur because of internal microbial seeding. Primary abscesses are rarely reported. We present 2 clinical cases featuring primary abscesses of the chiasmal-sellar region. To put into perspective the rarity of these findings, we performed a systematic review of existing clinical reports regarding this pathology. METHODS: A systematic review of literature was conducted to gather existing clinical reports on primary abscesses of the chiasmatic-sellar region. Two personal findings are added to the literature review, including a 13-year-old girl and a 58-year-old man who presented with chiasmal-sellar region primary abscesses. The diagnostic aspects, treatment strategy, and outcomes are discussed. RESULTS: Both patients included in the report had positive outcome. The pediatric patient developed a recurrence of the abscess and was treated accordingly. Overall, 41 cases of primary abscesses of this region have been reported in literature, of which 6 are in children under 18 years of age. The main nonspecific clinical manifestations include headaches, visual impairment, and endocrine pathology. Acute inflammatory responses are rarely seen, despite infectious genesis. Transnasal endoscopic surgical treatment offers diagnostic and treatment advantages. CONCLUSIONS: Proper diagnostic procedures can aid in correct treatment strategy and improve overall outcome.

Surgical Correction of a Clivus Cerebrospinal Fluid Fistula: A Technical Report.

BACKGROUND: Cerebrospinal fistulas of the clivus region often result from previous surgical intervention at the skull base. The localization and size of the fistula determine the appropriate treatment strategy. When flap closure is not possible, the microsuture technique with autograft placement provides a favorable outcome. METHODS: We present a technical report on the application of the microsuture technique for clivus region cerebrospinal fluid fistula closure in a patient with previous chordoma treatment and nonspecific coronavirus disease 2019 complications. RESULTS: The application of the microsuture technique resulted in stable remission of the fistula and complete regression of the clinical manifestations. CONCLUSIONS: The microsuture technique for clivus region fistula closure is a potentially valuable alternative to vascularized flap closure.

Anatomical Aspects of the Transnasal Endoscopic Access to the Craniovertebral Junction.

OBJECTIVE: Interest in endoscopic transnasal access has increased with continued technological advances in endoscopic technology. The goals of this study were to review the normal anatomy in transnasal endoscopic neurosurgery and outline the anatomical basis for an expanded surgical approach. Defining anatomical aspects of surgical endoscopy helps guide the surgeon by defining normal anatomy of the access vector. METHODS: This anatomic study was conducted on 15 adult male cadaver specimens using various microsurgical tools and endoscopic instruments and 1 intraoperative case. The vasculature was injected with colored silicone to aid visualization. Different transnasal approach techniques were used, with angles of endoscope access at 0°, 30°, 45°, and 70° accordingly for extensive anatomical mapping. RESULTS: The proximity of critical structures is different in each approach degree. A full understanding of the possible structures to be met during transnasal access is described. As a result of the study, anatomical aspects and important structures were outlined, and a surgical protocol was defined for minimal risk access in respect to normal anatomy of the area. CONCLUSIONS: Thorough knowledge of topographic anatomy of the craniovertebral junction is required for performing minimal-risk surgical intervention in this region. It is important to know all anatomical aspects of the transnasal approach in order to reduce the risk of damage to vital structures. Transnasal endoscopic surgery of the craniovertebral junction is a relatively new direction in neurosurgery; therefore, anatomical studies such as the one described in this article are extremely important for the development of this access method.

Endoscopic Transsphenoidal Approach in Treatment of Germinomas of the Chiasmosellar Region.

INTRODUCTION: Germinogenic central nervous system (CNS) tumors represent a heterogeneous group of tumors, constituting approximately 0.4% of all primary brain tumors. Removal of the tumor has no prognostic value. In "pure" primary germinomas of the CNS, the alpha-fetoprotein and human chorionic gonadotropin levels are within normal limits, and no specific biochemical tumor markers currently exist for this tumor type, making histological verification crucial for the choice of treatment tactics. When the tumor is located in the chiasmosellar region, one of the possible verification methods is endoscopic endonasal transsphenoidal biopsy. OBJECTIVE: The main objective of the study is to demonstrate the feasibility and safety of endoscopic transsphenoidal approach for histological verification of primary germinomas of the CNS with chiasmosellar localization. MATERIALS AND METHODS: The current study includes 13 patients with "pure" germinomas of the chiasmosellar region who underwent endoscopic endonasal surgical interventions with subsequent treatment according to the "Germinoma 2008" protocol. RESULTS: The extent of surgical intervention ranged from biopsy (4) to partial (5) and total (4) removal of the tumor. In all cases, histological verification of the diagnosis was achieved and none of the patients presented with cerebrospinal fluid leaks and/or meningitis in the postoperative period, allowing to evaluate endoscopic intervention in our patient series as safe and effective. Two out of 13 patients were lost to follow-up. CONCLUSION: The endoscopic endonasal approach for histological verification and removal of chiasmosellar region germinomas is safe, and in some cases, less traumatic for the patient than transcranial and transventricular approaches.

Neurophysiological Identification of Cranial Nerves During Endoscopic Endonasal Surgery of Skull Base Tumors: Pilot Study Technical Report.

INTRODUCTION: Intraoperative identification of cranial nerves is crucial for safe surgery of skull base tumors. Currently, only a small number of published papers describe the technique of trigger electromyography (t-EMG) in endoscopic endonasal removal of such tumors. OBJECTIVE: To assess the effectiveness of t-EMG in preventing intraoperative cranial nerve damage in endoscopic endonasal surgery of skull base tumors. MATERIALS AND METHODS: Nine patients were operated on using the endoscopic endonasal approach within a 1-year period. The tumors included large skull base chordomas and trigeminal neurinomas localized in the cavernous sinus. During the surgical process, cranial nerve identification was carried out using monopolar and bipolar t-EMG methods. Assessment of cranial nerve functional activity was conducted both before and after tumor removal. RESULTS: We mapped 17 nerves in 9 patients. Third, fifth, and sixth cranial nerves were identified intraoperatively. There were no cases of postoperative functional impairment of the mapped cranial nerves. In one case we were unable to get an intraoperative response from the fourth cranial nerve and observed its postoperative transient plegia (the function was normal before surgery). CONCLUSION: t-EMG allows surgeons to control the safety of cranial nerves both during and after skull base tumor removal.

Surgical Treatment of Skull Base Tumors, Extending to Craniovertebral Junction.

OBJECTIVE: To conduct a comparative analysis of 2 groups of patients with skull base chordomas extending onto the craniovertebral junction, who underwent surgical treatment using extracranial approaches with and without craniocervical fusion. METHODS: The study group included 29 patients with skull base chordomas, extending to the craniovertebral junction, who were operated on from 2000 to 2015. The patients underwent the following surgical treatment: posterior craniocervical fusion followed by tumor removal using transoral and combined transoral and transnasal approaches. The reference group included 21 patients with the same disease, who underwent tumor removal surgery using the transoral approach without craniocervical fusion. RESULTS: In the study group, in 27.5% of all cases (8 patients), the tumors were removed radically; in 65.5% of all cases (19 patients), the tumors were removed subtotally; and in 7% of all cases (2 patients), the tumors were removed partially. In the reference group, the extent of surgical radicality was as follows: radical, 0%; subtotal, 19% (4 cases); partial, 81% (17 cases). CONCLUSIONS: Use of the proposed surgical technique in clinical practice may help increase the radicality of tumor excisions, decrease the number of postoperative complications, accelerate the rehabilitation process, and increase the quality of life in patients with skull base tumors extending to the craniovertebral junction.