Skull Base Surgery Techniques Research Articles

The feasibility and clinical outcome of endoscopic transorbital transcavernous approaches with or without petrosectomy for petroclival lesions.

Petroclival tumors such as petroclival meningiomas or trigeminal schwannomas extending to the posterior cranial fossa are challenging to treat due to their deep-seated location and proximity to critical neurovascular structures. This study aimed to evaluate the feasibility, safety, and clinical outcomes of endoscopic transorbital surgery for the resection of central skull base tumors involving the petroclival area. The authors conducted a retrospective analysis of 32 patients with petroclival tumors including meningiomas and trigeminal schwannomas who underwent endoscopic transorbital surgery between September 2017 and December 2022. Preoperative clinical and radiological data were collected, and patients were followed up postoperatively for a median period of 34.7 months. Surgical technique, complications, and clinical outcomes were assessed. Endoscopic transorbital surgery provided a minimally invasive and direct corridor to the petroclival region. All 32 patients successfully underwent tumor resection, with gross-total or near-total tumor resection achieved in 28 patients. The mean tumor diameter was 3.5 cm. Based on tumor pathology, the endoscopic transorbital transcavernous trans-Meckel's cave approach (21 cases) or transorbital anterior transpetrosal approach (11 cases) was selected. The most common complication was facial paresthesia in 4 of 21 patients with trigeminal schwannomas and in 1 of 11 patients with petroclival meningiomas. Diplopia due to fourth cranial nerve injury occurred in 3 of 11 patients with petroclival meningiomas. Postoperative clinical improvement in neuralgic pain was observed in 3 of 4 patients. One patient developed a temporary facial palsy (House-Brackmann grade III) and another patient had transient paraparesis after removal of petroclival meningioma. Endoscopic transorbital surgery appears to be a safe and effective technique for the resection of petroclival lesions, offering excellent visualization and access to the tumor while minimizing morbidity. However, further studies with larger patient cohorts and longer follow-up are warranted to validate the long-term efficacy and safety of this approach. This study contributes to the growing body of evidence supporting the utility of endoscopic transorbital techniques in skull base surgery.

Advances in Skull Base Reconstruction After Transnasal Endoscopy

Endoscopic transnasal approach have experienced rapid development and gradual maturation in just a few decades (Kassam AB, Prevedello DM, Carrau RL, et al, 2011; Eloy J A, Vivero R J, Hoang K, et al, 2009). It has expanded from the removal of conventional pituitary tumours to the application of an endoscopic extended transsphenoidal approach for the resection of tumours in the intrasellar, suprasellar and even ventricular systems (Cappabianca P, Cavallo L M, Esposito F, et al, 2008). Larger bone and dural defects at the skull base, causing more severe postoperative complications and resulting in a multiplication of the healthcare burden (Eloy J A, Shukla P A, Choudhry O J, et al, 2013). Skull base Reconstruction after tumour removal has become a great challenge. Currently, skull base reconstruction is mainly divided into soft and rigid reconstruction, and soft reconstruction is represented by the technique of pedicled nasal septum mucosal flap (PNSF) (Thorp B D, Sreenath S B, Ebert C S, et al, 2014)0. As for rigid reconstruction, it is still controversial (Shin J, Forbes J, Lehner K, et al, 2019; Eloy J A, Shukla P A, Choudhry O J, et al, 2012). From the current studies, rigid reconstruction has a role that cannot be ignored. In this article, we will describe the development of skull base surgery and several high-profile skull base reconstruction techniques.

Endoscopic Anatomy of the Skull Base.

Presently, endoscopic skull base surgery has undergone significant advancements since its inception over two decades ago. Nevertheless, it is imperative to underscore that the fundamental basis of all surgical procedures lies in the meticulous understanding of anatomy, with particular emphasis on the ventral anatomy. This facet has recently garnered increased attention.Following the advancements in endoscopic skull base surgery techniques, this chapter will concentrate on the pertinent anatomical considerations that serve as key foundations for successful procedures. These considerations are categorized into two planes: the sagittal plane and the coronal plane.The sagittal plane is further subdivided into five distinct approaches, namely,(1) the transcribriform approach, (2) the transplanum approach, (3) the transsellar approach, (4) the transclival approach, and (5) the transodontoid approach.On the other hand, the coronal plane is delineated into seven specific zones to facilitate comprehension and potential applications: (1) the petrous apex approach, (2) the intrapetrous approach, (3) the suprapetrous approach, (4) the cavernous sinus approach, (5) the infratemporal approach, (6) the medial condyle approach, and (7) the jugular foramen approach.By organizing the anatomical aspects in this systematic manner, the information provided becomes more accessible, fostering a comprehensive understanding of the subject matter for potential future application.

The Current State of Visualization Techniques in Endoscopic Skull Base Surgery.

Skull base surgery has undergone significant progress following key technological developments. From early candle-lit devices to the modern endoscope, refinements in visualization techniques have made endoscopic skull base surgery (ESBS) a standard practice for treating a variety of conditions. The endoscope has also been integrated with other technologies to enhance visualization, including fluorescence agents, intraoperative neuronavigation with augmented reality, and the exoscope. Endoscopic approaches have allowed neurosurgeons to reevaluate skull base neuroanatomy from new perspectives. These advances now serve as the foundation for future developments in ESBS. In this narrative review, we discuss the history and development of ESBS, current visualization techniques, and future innovations.

Nasal resonance changes after endoscopic endonasal transsphenoidal skull base surgery: Analysis of voice quality.

ObjectivesTo study the effect of endoscopic endonasal transsphenoidal surgery on voice quality in patients with pituitary lesions.MethodsAn observational study comparing voice quality before and after surgery was conducted between September 2015 and September 2017 at Srinagarind Hospital, Khon Kaen University, Thailand. Pituitary tumor patients who underwent endoscopic endonasal transsphenoidal surgery were recruited. The nasal corridors were created with a type I (preserving both middle turbinates with a rescue flap) or type II (cutting one middle turbinate with a raised nasoseptal flap) for the binostril with four‐hand technique. All patients were evaluated for nasal resonance, acoustic parameters, acoustic perception, and self‐assessment of their satisfaction with postoperative voice changes with a visual analog scale (VAS). The patients were evaluated 1 day before surgery and at 1 and 3 months after surgery.ResultsForty‐four patients, including 19 males and 25 females with a mean age of 50.0 ± 15.6 years, were enrolled. Mean scores for nasal resonance and all acoustic parameters were not significantly changed after surgery for either nasal corridor type (p > .05). Regarding acoustic perception, word and sentence and GIRBAS scores showed no significant difference before and after surgery (p > .09) in either type of nasal corridor. There was no incidence of hypernasality voice after surgery. Patients' self‐satisfaction ratings (i.e., VAS) with voice quality were high and showed no significant change 1 and 3 months postsurgery (p > .05).ConclusionsThese endoscopic endonasal transsphenoidal approaches are minimally invasive skull base surgery techniques that have minimal effects on postsurgery voice quality.Trial RegistrationThis trial was registered at ClinicalTrial.gov (NCT02828514).Level of Evidence4.

Combined endoscopic endonasal and transorbital approach to skull base tumors: a systematic literature review.

In the last decades, there has been a marked evolution in skull base surgery techniques and more recently a combination of different corridors has been proposed and used in order to improve angles of attack, shorten working distances, and ameliorate visualization of skull base lesions. Recently, the endoscopic endonasal and transorbital routes have been combined as multiportal approach to reach and treat complex skull base neoplasms. The aim of this paper is to examine data extracted from the recent literature about the feasibility and effectiveness of combined endonasal and transorbital endoscopic multiportal surgery. A PubMed comprehensive search of literature published until October 2020 was conducted. Nine studies, regarding 24 patients, were included. The majority of tumors were meningiomas (62.5%), mostly located at the spheno-orbital region (93.3%). GTR was accomplished in 10 patients (41.7%), NTR in two patients (8.3%). Endonasal transpterygoid approach (N.=8) and superior eyelid access (N.=17) were the most used routes used. No case of CSF fistula was observed, and the most common complication was a transient periorbital edema. The average hospitalization time (days) was five days. A combined endoscopic endonasal and transorbital multiportal approach grants an adequate corridor to access several skull base tumors, such as those extending towards the paramedian aspects, providing good outcomes in terms of extent of tumor resection with acceptable rates of complications. These preliminary results might encourage the use of multiportal approaches in selected complex skull base neoplasms.

Surgical Management of Skull Base and Spine Chordomas

Management of chordoma along the cranial-spinal axis is a major challenge for both skull base and spinal surgeons. Although chordoma remains a rare tumor, occurring in approximately 1 per 1 million individuals, its treatment poses several challenges. These tumors are generally poorly responsive to radiation and chemotherapy, leading to surgical resection as the mainstay of treatment. Due to anatomic constraints and unique challenges associated with each primary site of disease, gross total resection is often not feasible and is associated with high rates of morbidity. Additionally, chordoma is associated with high rates of recurrence due to the tumor's aggressive biologic features, and postoperative radiation is increasingly incorporated as a treatment option for these patients. Despite these challenges, modern-day surgical techniques in both skull base and spinal surgery have facilitated improved patient outcomes. For example, endoscopic endonasal techniques have become the mainstay in resection of skull base chordomas, improving the ability to achieve gross total resection, while reducing associated morbidity of open transfacial techniques. Resection of spinal chordomas has been facilitated by emerging techniques in preoperative imaging, intraoperative navigation, spinal reconstruction, and radiotherapy. Taken collectively, the treatment of chordoma affecting the skull base and spinal requires a multidisciplinary team of surgeons, radiation oncologists, and medical oncologists who specialize in the treatment of this challenging disease.

Surgical anatomy and technical nuances of the endoscopic endonasal approach to the anterior cranial fossa.

Endoscopic endonasal approaches (EEA) to the skull base have significantly impacted the management of lesions located in the cranial base. Specifically, lesions arising from the anterior cranial fossa, such as pituitary macroadenomas, craniopharyngiomas meningiomas and craniofacial malignancies have benefited from the development of such approaches. Understanding of the anatomy of the anterior fossa is of utmost importance for the successful selection of the approach and application of surgical techniques in EEA. In the current manuscript, we review the most relevant points of surgical anatomy and nuances of the surgical technique of EEA to the anterior fossa. Anatomical landmarks for the transtuberculum transplanum and transcribriform approaches are discussed and a step-by-step description for those approaches is presented. We reinforce that safe and effective application of such techniques follow the same principles of other skull base surgery techniques: mastering of surgical anatomy, adequate case selection, correct instrumentation and surgical experience.

Open and Endoscopic Skull Base Approaches

Surgical approaches to the skull base have been evolving at an incredible rate in the past 30 years. The advent of the endoscope has multiplied the available approaches while reducing morbidity. Otolaryngologists and neurosurgeons performing these operations must stay updated in recent trends and techniques to determine the best options for patients. Twenty years have passed since the adoption of the endoscope in skull base surgery but new techniques are still being introduced on an annual basis. Most notably are the “cross court” techniques utilizing the contralateral transmaxillary (CTM) approach and transorbital neuroendoscopic surgery (TONES). Both approaches allow the surgeon increased angulation and access to lateral structures limited by the endonasal approach. Surgeons must understand the patient factors, pathology, and available resources as well as the armamentarium of approaches to the skull base to offer the best option for individual patients.

Implementation of cisternostomy as adjuvant to decompressive craniectomy for the management of severe brain trauma

ObjectiveTo evaluate the value of an adjuvant cisternostomy (AC) to decompressive craniectomy (DC) for the management of patients with severe traumatic brain injury (sTBI).MethodsA single-center retrospective quality control analysis of a consecutive series of sTBI patients surgically treated with AC or DC alone between 2013 and 2018. A subgroup analysis, “primary procedure” and “secondary procedure”, was also performed. We examined the impact of AC vs. DC on clinical outcome, including long-term (6 months) extended Glasgow outcome scale (GOS-E), the duration of postoperative ventilation, and intensive care unit (ICU) stay, mortality, Glasgow coma scale at discharge, and time to cranioplasty. We also evaluated and analyzed the impact of AC vs. DC on post-procedural intracranial pressure (ICP) and brain tissue oxygen (PbO2) values as well as the need for additional osmotherapy and CSF drainage.ResultsForty patients were examined, 22 patients in the DC group, and 18 in the AC group. Compared with DC alone, AC was associated with significant shorter duration of mechanical ventilation and ICU stay, as well as better Glasgow coma scale at discharge. Mortality rate was similar. At 6-month, the proportion of patients with favorable outcome (GOS-E ≥ 5) was higher in patients with AC vs. DC [10/18 patients (61%) vs. 7/20 (35%)]. The outcome difference was particularly relevant when AC was performed as primary procedure (61.5% vs. 18.2%; p = 0.04). Patients in the AC group also had significant lower average post-surgical ICP values, higher PbO2 values and required less osmotic treatments as compared with those treated with DC alone.ConclusionOur preliminary single-center retrospective data indicate that AC may be beneficial for the management of severe TBI and is associated with better clinical outcome. These promising results need further confirmation by larger multicenter clinical studies. The potential benefits of cisternostomy should not encourage its universal implementation across trauma care centers by surgeons that do not have the expertise and instrumentation necessary for cisternal microsurgery. Training in skull base and vascular surgery techniques for trauma care surgeons would avoid the potential complications associated with this delicate procedure.

Meningiomas petroclivales. Estrategia quirúrgica endoscópica a propósito de dos casos

A pesar del desarrollo de las técnicas quirúrgicas de base de cráneo, los meningiomas petroclivales constituyen un reto para el neurocirujano debido a su localización y relación con estructuras neurológicas y vasculares críticas. Se reportan 2 pacientes con diagnóstico de meningioma petroclival que recibieron tratamiento por etapas incluyendo derivación ventrículo peritoneal asistida por endoscopia para la hidrocefalia, abordaje endonasal endoscópico (AEE) extendido al ápex petroso, keyhole subtemporal y retromastoideo con remoción de la lesión. La evolución fue satisfactoria. Se concluyó que los abordajes endoscópicos y por etapas constituyen una excelente opción en el tratamiento de los meningiomas petroclivales.

Use of Autologous Fat Grafts for the Endoscopic Reconstruction of Skull Base Defects: Indications, Outcomes, and Complications.

Background The use of abdominal free fat is a traditional surgical method for the repair and reconstruction of the anterior skull base. Our objective is to assess the outcomes associated with the autologous fat graft to endoscopically repair anterior skull base defects at a single tertiary care center. Methods All patients, who underwent endoscopic skull base repair utilizing abdominal free fat from September 2009 to June 2016, were included for retrospective chart review. Evaluated outcome measurements included (1) the successful closure of preoperative and intraoperative cerebrospinal fluid (CSF) leaks and (2) complications at both donor and recipient graft sites during the postoperative periods. Four representative clinical cases have additionally been selected to highlight the common indications for which the fat graft may be effective in skull base reconstruction. Results Of the 27 patients who were identified for inclusion in this review, 25 (92.6%) demonstrated successful repair of preoperative or intraoperative CSF leaks following primary skull base repair. Two patients developed recurrent CSF leaks occurring about 1 week after their primary closures, and a secondary closure rate of 96.3% was achieved with use of fat grafts. Other complications included seroma and hematoma formation at the abdominal donor sites, each occurring in 1 patient. Conclusions The use of autologous fat remains a viable option for grafting material during endoscopic skull base reconstruction. Despite the wide variety of closure techniques in skull base surgery, autologous fat provides safe and easily accessible material to repair CSF leaks.

The Validity of Training Endoscopic Sinus and Skull Base Surgery Techniques on the Experimental Head Model.

The aim of this study was to better understand the usual learning curve in acquiring endonasal endoscopic sinus and skull base surgery (ESSBS) techniques during the novice training on the lamb's head model. Ten novices were asked to perform 10 bilateral dissections on the particular lamb's head each. The dissections were uniform, consisted of 10 well-defined steps, beginning from the simple removal of the inferior turbinate, and ending with more complicated procedures like cerebrospinal fluid leak repair, Draf 3 procedure for the frontal sinus and elevation of the nasal septal flap. The dissections have been supervised by experienced surgeons. A set of standard ESSBS instruments and 0° and 45° endoscopes have been used under the navigational system. The time required to complete each step has been measured in minutes. In general and quite expectedly, time rates have been obviously lowering as the number of the dissections performed has been growing in each of the participants. Training of the endonasal ESSBS techniques on the lamb's head proved to be useful for novices in getting basic surgical skills in the field. Because of the high degree of anatomic similarity and high level of the anatomic dimensions congruency between the lamb's head and human head (sheep's head has bigger dimensions!) it proved to be an essential preparation for the human cadaveric dissection. The median values of the time rates having been needed to complete the particular of the 10 steps in the last novices' dissections could be accepted as an orientation, just suggesting that once the time needed to complete 1 of the 10 steps has been and achieved by the particular novice, this could be an approximate sign of the maturity for the exercises on human cadaver head.

A Systematic Review of Closure Techniques in Lateral Skull Base Surgery

A Systematic Review of Closure Techniques in Lateral Skull Base Surgery

Reconstructive techniques in skull base surgery after resection of malignant lesions

In this manuscript, we will provide a panorama of the current status of skull base reconstruction following endoscopic endonasal or open resection of malignant lesions, focusing on novel options and recent modifications of previously described techniques. New developments in skull base reconstruction continue to arise, mostly as in the form of vascularized pedicled flaps that can be used following endoscopic and open resections of the skull base. Resection of skull base tumors, often creating large dural defects that couple with extensive intradural dissection, involving multiple cisterns or the third ventricle, may lead to high-flow cerebrospinal fluid leaks. Reconstruction of the skull base is paramount to achieve an uncomplicated postoperative course. Repair of small dural defects can be reliably achieved using a multilayer grafting technique, which yields a high success rate (>90%). Repair of larger defects associated with a high-flow cerebrospinal fluid leak, or defects in previously irradiated fields, often requires a local or regional pedicled vascularized graft as the first reconstructive choice. When these are unavailable, free microvascular tissue transfer remains an option.

Optic Canal Decompression: Comparing the Endonasal Endoscopic and Transcranial Approaches

Introduction: Several pathologies can affect the optic canal (OC) and the optic nerve (ON) and ophthalmic artery. Tumors, vascular abnormalities, bony dysplasia, connective tissue disease, and trauma are examples. The compression of the ON, leading to visual impairment, is an indication for decompression OC. The OC decompression is usually recommended through a transcranial approach. Recently, the advances in endoscopic skull base surgery techniques allowed achieving the decompression through an endoscopic endonasal approach (EEA), because of the straightforward access to the OC in the sphenoid sinus.

Reshaping the zygomatic complex: A "small step" in frontotemporal craniotomy and a "big leap" in exposure.

Pterional or fronto-temporal craniotomy, developed by Prof. M. G. Yasargil, is among the most familiar skull base surgery techniques. The cranio-orbito zygomatic (COZ) approach evolved to address the significant limitations of the pterional exposure in excising some parasellar lesions. Although extremely versatile, the COZ technique involves extensive dissection of the cranio-facial soft tissue and reconstruction towards the end of the procedure. The zygomatic reshaping is a minor modification of the pterional approach, which enhances the exposure possible through the classical approach and often circumvents the need for an orbito-zygomatic osteotomy. To demonstrate the technique of reshaping of the zygomatic complex for an optimum surgical exposure and cosmetic results. Between April 2013 and December 2014, 8 patients with various middle and anterior skull base lesions were operated using this technique. These patients form the clinical material for this study. The clinical details, radiological images and follow-up data of these patients were collected for this clinical series. No mortality or significant morbidity were noted in this series. The post-operative cosmetic results were also acceptable. A quick and easy modification of the classical pterional approach through zygomatic reshaping has the potential to provide a significantly enhanced surgical exposure for parasellar lesions. Using this approach, it might be possible to avoid an extensive orbito-zygomatic osteotomy in suitable lesions.

Reconstructive Techniques in Skull Base Surgery for Head and Neck Malignancies

Reconstructive Techniques in Skull Base Surgery for Head and Neck Malignancies

Surgical treatment of jugular foramen schwannomas

ObjectiveWe present our experience with surgery of jugular foramen schwannomas with special consideration of clinical presentation, surgical technique, complications, and outcomes. MethodsThis retrospective study includes ten patients with jugular foramen schwannomas treated by the senior author between January 2007 and December 2012. Three patients had undergone partial tumour resection elsewhere. The initial symptom for which they sought medical help was hearing loss, dysphagia, hoarseness, and shoulder weakness. Preoperative glossopharyngeal and vagal nerve deficits were the most common signs. In our series, tumour extension was classified according to Kaye-Pellet grading system. In two cases the tumours were classified into type A and 8 patients presented with type D tumours. A retromastoid suboccipital craniotomy was performed for type A tumours and modifications of cranio-cervical approach were suitable for type D. ResultsNo death occurred in this series. Four patients deteriorated after surgery: in two patients preoperative cranial nerve deficits deteriorated after surgery while new cranial nerve palsy occurred in 2 other patients. In four patients, the cranial nerve dysfunction had improved at the last follow-up examination. In all other patients, the cranial nerve dysfunction remained the same. One patient experienced tumour recurrence over a follow-up period of 40 months. This patient underwent a successful second surgery without further evidence of tumour growth. ConclusionsJugular foramen schwannomas can be radically managed with the use of skull base surgery techniques. However, the surgical treatment of jugular foramen schwannomas carries a significant risk of the lower CN deficits.

Robotic Navigation of the Infratemporal Fossa and Midline Cranial Base

Objective: With the expanding application of endoscopic techniques in skull base surgery, we conducted a feasibility preclinical study on robotic exploration of the infratemporal and midline cranial base using the Da Vinci robotic platform.