Magnetic resonance angiographic study of variations in course of paraclival and parasellar internal carotid artery in relation to expanded endonasal endoscopic approaches.

AIMS: To study the variations in the course of the paraclival and parasellar carotid arteries in normal subjects using magnetic resonance angiography as is relevant from an endoscopic endonasal perspective. METHODS: Two hundred MR angiographies of normal subjects were analyzed in a prospective study. The intercarotid distances were measured at fixed points along the paraclival and parasellar segments of the internal carotid artery. The intercarotid spaces thus obtained were categorized into trapezoid, square and hourglass shapes. The angle between the posterior ascending vertical and horizontal bend of the parasellar ICA was also measured and analyzed. RESULTS: The trapezoid shape of intercarotid space is the most common (52.5%), followed by the square (35%) and the hourglass (12.5%) shaped spaces. Angle of < 80° between the posterior ascending vertical and horizontal bend of the parasellar ICA was found in 39% of subjects, angle between 80° and 100° was found in 9% subjects, angle > 100° was found in 43% while asymmetric angles on the two sides was found in 9% of subjects. CONCLUSION: A thorough understanding of the course of the ICA is important in planning the approach and preventing injury to the ICA.

Clinical Studies and Pre-clinical Animal Models on Facial Nerve Preservation, Reconstruction, and Regeneration Following Cerebellopontine Angle Tumor Surgery-A Systematic Review and Future Perspectives.

Background and purpose: Tumorous lesions developing in the cerebellopontine angle (CPA) get into close contact with the 1st (cisternal) and 2nd (meatal) intra-arachnoidal portion of the facial nerve (FN). When surgical damage occurs, commonly known reconstruction strategies are often associated with poor functional recovery. This article aims to provide a systematic overview for translational research by establishing the current evidence on available clinical studies and experimental models reporting on intracranial FN injury. Methods: A systematic literature search of several databases (PubMed, EMBASE, Medline) was performed prior to July 2020. Suitable articles were selected based on predefined eligibility criteria following the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Included clinical studies were reviewed and categorized according to the pathology and surgical resection strategy, and experimental studies according to the animal. For anatomical study purposes, perfusion-fixed adult New Zealand white rabbits were used for radiological high-resolution imaging and anatomical dissection of the CPA and periotic skull base. Results: One hundred forty four out of 166 included publications were clinical studies reporting on FN outcomes after CPA-tumor surgery in 19,136 patients. During CPA-tumor surgery, the specific vulnerability of the intracranial FN to stretching and compression more likely leads to neurapraxia or axonotmesis than neurotmesis. Severe FN palsy was reported in 7 to 15 % after vestibular schwannoma surgery, and 6% following the resection of CPA-meningioma. Twenty-two papers reported on experimental studies, out of which only 6 specifically used intracranial FN injury in a rodent (n = 4) or non-rodent model (n = 2). Rats and rabbits offer a feasible model for manipulation of the FN in the CPA, the latter was further confirmed in our study covering the radiological and anatomical analysis of perfusion fixed periotic bones. Conclusion: The particular anatomical and physiological features of the intracranial FN warrant a distinguishment of experimental models for intracranial FN injuries. New Zealand White rabbits might be a very cost-effective and valuable option to test new experimental approaches for intracranial FN regeneration. Flexible and bioactive biomaterials, commonly used in skull base surgery, endowed with trophic and topographical functions, should address the specific needs of intracranial FN injuries.

Primary Lymphoma of Internal Acoustic Meatus Mimicking Vestibular Schwannoma-A Rare Diagnostic Dilemma.

Background/Setting A subject presenting with a unilateral sensorineural hearing loss and with vertigo/imbalance and a lesion of internal acoustic meatus (IAM) most often represents a vestibular schwannoma. Several alternative pathologies involving the region, with clinical and neuroradiological similarities, could lead to an error in judgement and management. Rare tumors of the IAM pose unique diagnostic difficulty. A rare case that we present here had a typical history and imaging findings suggestive of vestibular schwannoma. A primary central nervous system (CNS) lymphoma was diagnosed in later stages of brain involvement warranting a retrospective analysis of the entity. Case Summary An 80-year-old male presented with unilateral sensorineural hearing loss, vertigo, and imbalance. On imaging, he was found to have a lesion in the left internal auditory meatus, reported as a vestibular schwannoma and operated upon. Subject's condition worsened with time and a repeat imaging was suggestive of a CNS lymphoma with lesions involving bilateral cerebellum and subcortical white matrix. Conclusion To conclude, primary CNS lymphoma presenting an isolated lesion in the IAM with no other parenchymal lesions at presentation is a rare incidence; to our knowledge this is the first case of such unique presentation.

Surgical Management of Tuberculum Sellae Meningioma: Our Experience and Review of the Literature.

BACKGROUND: Tuberculum sellae (TS) meningiomas are benign lesions that produce neurological deficits through a mass effect on vital neurovascular structures. The treatment of choice is surgical removal with the ultimate goal to improve vision and achieve total tumor removal. OBJECTIVE: We analyzed clinical features, tumor characteristics, and surgical approaches in 62 consecutive patients with TS meningiomas to identify factors influencing the postoperative outcome. METHODS: The authors reviewed the medical records of all patients of TS meningiomas who underwent surgery at our institute between 2005 and 2018. Pre- and postoperative clinical data, including the operative findings, of these patients were analyzed. RESULTS: Sixty-two patients who underwent surgery for removal of TSM, transcranial (TCA) in 38, and endoscopic endonasal (EEA) in 24, were identified. Gross total resection was performed in 84% and 87.5% patients in the TCA and EEA groups, respectively. A significantly higher rate of visual improvement was observed in the EEA group as compared to TCA (96% versus 79%). Visual worsening after surgery was greater with TCA than EEA (21% versus 4%). Fourteen (37%) patients in the TCA group experienced different postoperative complications, and CSF leak was the main complication in the EEA group. CONCLUSIONS: TCA and EEA are both associated with higher rates of GTR and visual improvement without compromising the safety of the procedure. An optimal outcome, however, depends on the careful selection of cases based on the tumor location and morphology, and the surgeon's familiarity with the surgical approach.

Endoscopic endonasal transplanum transtuberculum approach for retrochiasmatic craniopharyngiomas: Operative nuances.

The surgical treatment of craniopharyngiomas is challenging. An optimal surgical approach is extremely important to achieve complete removal of the tumor, which is often the goal of treatment. Conventionally, the endoscopic transsphenoidal approach is used for resection of craniopharyngiomas that are essentially confined to the sellar cavity, or have smaller suprasellar extension. However, the tumors located in the retrochiasmatic space are difficult to remove surgically due to a poor access. Traditionally, various transcranial microsurgical routes have been employed with limited success for resection of retrochiasmatic craniopharyngiomas. The transcranial approaches generally do not provide adequate exposure of the tumors originating in the space under the optic chiasm and nerves. Recently, the extended endonasal endoscopic surgical route, obtained by removal of the tuberculum sellae and planum sphenoidale, has been used with great success in the surgical management of tumors lying ventral to the optic chiasm, including craniopharyngiomas. It offers a direct midline access to the retrochiasmatic space and provides excellent visualization of the undersurface of the optic chiasm. It also allows extracapsular dissection using binostril-bimanual technique and facilitates complete removal of these formidable tumors. In this report, we describe step-by-step, the technical details of the endonasal endoscopic transplanum transtuberculum approach with emphasis on the operative nuances for removal of retrochiasmatic craniopharyngiomas.

Current perspectives in the management of glomus jugulare tumors.

Glomus jugulare tumors are benign but locally aggressive tumors. Their location, spread to adjacent areas and biological behavior have been extensively studied and reported. However, controversy exists regarding the role of surgery and stereotactic radiosurgery. The optimal plan of management of the tumor in close proximity to the facial and lower cranial nerves, the internal carotid and vertebral arteries, the venous sinuses, and the neuraxis is still nebulous. This review will discuss the differing viewpoints and attempts to propose a rational strategy in dealing with these tumors.

Extended endoscopic endonasal transsphenoidal approach for retrochiasmatic craniopharyngioma: Surgical technique and results.

OBJECTIVE: Surgical treatment of retrochiasmatic craniopharyngioma still remains a challenge. While complete removal of the tumor with preservation of the vital neurovascular structures is often the goal of the treatment, there is no optimal surgical approach available to achieve this goal. Transcranial and transsphenoidal microsurgical approaches, commonly used in the past, have considerable technical limitations. The extended endonasal endoscopic surgical route, obtained by removal of tuberculum sellae and planum sphenoidale, offers direct midline access to the retrochiasmatic space and provides excellent visualization of the undersurface of the optic chiasm. In this report, we describe the technical details of the extended endoscopic approach, and review our results using this approach in the surgical management of retrochiasmatic craniopharyngiomas. METHODS: Fifteen children, including 9 girls and 6 boys, aged 8 to 15 years underwent surgery using extended endoscopic transsphenoidal approach between 2008 and 2014. Nine patients had a surgical procedure done previously and presented with recurrence of symptoms and regrowth of their residual tumors. RESULTS: A gross total or near total excision was achieved in 10 (66.7%) patients, subtotal resection in 4 (26.7%), and partial removal in 1 (6.7%) patient. Postoperatively, headache improved in 93.3%, vision recovered in 77.3%, and the hormonal levels stabilised in 66.6%. Three patients (20%) developed postoperative CSF leaks which were managed conservatively. Three (20%) patients with diabetes insipidus and 2 (13.3%) with panhypopituitarism required long-term hormonal replacement therapy. CONCLUSIONS: Our early experience suggests that the extended endonasal endoscopic approach is a reasonable option for removal of the retrochiasmal craniopharyngiomas. Compared to other surgical approaches, it provides better opportunities for greater tumor removal and visual improvement without any increase in risks.

Surgical management of selected pituitary macroadenomas using extended endoscopic endonasal transsphenoidal approach: early experience.

BACKGROUND AND OBJECTIVES: The endoscopic transsphenoidal approach is commonly used surgical approach for pituitary adenomas. However, adenomas with dumbbell configuration, pure suprasellar location, and fibrous consistency are difficult to remove by this approach. Recently, the extended endoscopic endonasal approach (EEEA) has been utilized to excise this subgroup of pituitary adenomas successfully. MATERIALS AND METHODS: Between January 2009 and December 2011, 13 patients with pituitary macroadenomas were treated with EEEA. The tumor subgroups included: Dumbbell tumor configuration (4), pure suprasellar tumor location (2), and large suprasellar tumors with subfrontal extension (2). Five patients had fibrous/recurrent tumors and required addition of transtubercular-transplanum extension to the standard endoscopic endonasal exposure for radical resection. RESULTS: The tumor removal was gross total in 8 (61.5%) patients, subtotal in 4 (30.7%), and partial in 1 (7.7%) patient. Clinical improvement was observed in almost all patients, immediate relief in headaches in 88% and normalization of vision in 90% of patients with pre-operative visual disturbances. Three patients with secreting adenomas, two with growth hormone-secreting adenomas and one with prolactin-secreting adenoma, had normalization of hormonal status. Three patients developed temporary diabetes insipidus two patients suffered transient ischemic attacks and one patient with a recurrent giant pituitary adenoma experienced a serious injury to the perforating artery. Four patients (30.7%) developed post-operative cerebrospinal rhinorrhea and two patients required surgical repair. CONCLUSIONS: Our early experience suggests that the EEEA offers a potentially viable treatment option in certain pituitary tumors which are difficult to remove by the standard endoscopic approaches. However, longer follow-up and larger series are needed to establish the efficacy of this approach.