Ali O. Jamshidi

Nuances in the Treatment of Malignant Tumors of the Clival and Petroclival Region

Introduction Malignancies of the clivus and petroclival region are mainly chordomas and chondrosarcomas. Although a spectrum of malignancies may present in this area, a finite group of commonly encountered malignant pathologies will be the focus of this review, as they are recognized to be formidable pathologies due to adjacent critical neurovascular structures and challenging surgical approaches. Objectives The objective is to review the literature regarding medical and surgical management of malignant tumors of the clival and petroclival region with a focus on clinical presentation, diagnostic identification, and associated adjuvant therapies. We will also discuss our current treatment paradigm using endoscopic, open, and combined approaches to the skull base. Data Synthesis A literature review was conducted, searching for basic science and clinical evidence from PubMed, Medline, and the Cochrane Database. The selection criteria encompassed original articles including data from both basic science and clinical literature, case series, case reports, and review articles on the etiology, diagnosis, treatment, and management of skull base malignancies in the clival and petroclival region. Conclusions The management of petroclival malignancies requires a multidisciplinary team to deliver the most complete surgical resection, with minimal morbidity, followed by appropriate adjuvant therapy. We advocate the combination of endoscopic and open approaches (traditional or minimally invasive) as required by the particular tumor followed by radiation therapy to optimize oncologic outcomes.

Immediate complications associated with high-flow cerebrospinal fluid egress during endoscopic endonasal skull base surgery.

Endoscopic expanded endonasal approaches (EEAs) to the skull base are increasingly being used to address a variety of skull base pathologies. Postoperative CSF leakage from the large skull base defects has been well described as one of the most common complications of EEAs. There are reports of associated formation of delayed subdural hematoma and tension pneumocephalus from approximately 1 week to 3 months postoperatively. However, there have been no reports of immediate complications of high-volume CSF leakage from EEA skull base surgery. The authors describe two cases of EEAs in which complications related to rapid, large-volume CSF egress through the skull base surgical defect were detected in the immediate postoperative period. Preventive measures to reduce the likelihood of these immediate complications are presented.

Endonasal Resection of Craniopharyngiomas: Post-operative Management

Abstract Craniopharyngiomas are formidable tumors; their predilection for the suprasellar space and ability to adhere to surrounding structures renders their safe removal a daunting challenge. Several approaches have been proposed for their surgical treatment, including pterional-transsylvian, fronto-lateral, supraorbital, interhemispheric, subfrontal, transsphenoidal and even transpetrosal approaches. Recent advances in technology and a more thorough understanding of skull base anatomy from a ventral perspective have allowed the addition of the endonasal corridor under endoscopic visualization to the armamentarium of the skull base surgeon who deals with these lesions. The expanded endonasal approaches (EEAs), specifically the transsellar, transtuberculum, and transplanum modules, offer several advantages over their transcranial counterparts: direct visualization of the main tumor component and vital surrounding structures without the need for any brain or optic apparatus retraction is the main benefit over traditional techniques. The endonasal corridor grants ample access to the sellar and suprasellar compartments, as well as the anterior, middle, and posterior cranial fossae, when necessary. Direct visualization of the superior hypophyseal arteries, pituitary stalk and optic nerves and chiasm enables safe, microsurgical dissection of these structures from the tumor surface. Finally, the ventral perspective provides the surgeon with a superb view of the walls of the third ventricle, provided the tumor has violated them, a notoriously difficult area to safely access from a transcranial route.Craniopharyngiomas are formidable tumors; their predilection for the suprasellar space and ability to adhere to surrounding structures renders their safe removal a daunting challenge. Several approaches have been proposed for their surgical treatment, including pterional-transsylvian, fronto-lateral, supraorbital, interhemispheric, subfrontal, transsphenoidal and even transpetrosal approaches. Recent advances in technology and a more thorough understanding of skull base anatomy from a ventral perspective have allowed the addition of the endonasal corridor under endoscopic visualization to the armamentarium of the skull base surgeon who deals with these lesions. The expanded endonasal approaches (EEAs), specifically the transsellar, transtuberculum, and transplanum modules, offer several advantages over their transcranial counterparts: direct visualization of the main tumor component and vital surrounding structures without the need for any brain or optic apparatus retraction is the main benefit over traditional techniques. The endonasal corridor grants ample access to the sellar and suprasellar compartments, as well as the anterior, middle, and posterior cranial fossae, when necessary. Direct visualization of the superior hypophyseal arteries, pituitary stalk and optic nerves and chiasm enables safe, microsurgical dissection of these structures from the tumor surface. Finally, the ventral perspective provides the surgeon with a superb view of the walls of the third ventricle, provided the tumor has violated them, a notoriously difficult area to safely access from a transcranial route.

Skull Base Reconstruction Following Resection of Skull Base Chordomas and Chondrosarcomas

Abstract Resection of skull base chordomas and chondrosarcomas can create large dural defects that involve multiple cisterns or the third ventricle leading to high-flow cerebrospinal fluid leaks. Reconstruction of the skull base is essential to an uncomplicated postoperative course. In general, small dural defects can be repaired successfully with multilayer graft in at least 90% of cases. However, repair of larger defects with high-flow cerebrospinal fluid leakage, or of defects in the petroclival area, is more challenging and often requires a local or regional pedicled vascularized graft. When these are unavailable, free microvascular tissue transfer is an option. In this chapter, we discuss all available options to reconstruct skull base defects following endoscopic endonasal or open resection of petroclival chordomas and chondrosarcomas.

Anatomical Approaches to Giant Pituitary Tumors

Although several definitions have been proposed, giant pituitary adenomas are most commonly defined in the literature as tumors 4 cm or greater in maximum diameter. The tumor size, invasiveness, and irregular extension are the challenges involved in the management of these pathologies, which often require more than one surgical approach or treatment modality. The degree of radical resection of giant adenomas is restricted to less than 50% in every published surgical study and is associated with a higher complication rate compared with non-giant pituitary adenomas. Additional radiation therapy and medical therapy may be necessary to obtain long-term control of tumor growth. Several authors use the microscopic transsphenoidal or various frontal and frontotemporal transcranial routes as their choice for surgical management of giant pituitary adenomas. Endoscopic endonasal approaches have been used increasingly over the last decade for the treatment of many extended skull base tumors, including giant pituitary adenomas.