Technological and Ideological Innovations in Endoscopic Skull Base Surgery

Current and Future Advances in Surgical Therapy for Pituitary Adenoma

The vital physiological role of the pituitary gland, alongside its proximity to critical neurovascular structures, means that pituitary adenomas can cause significant morbidity or mortality. While enormous advancements have been made in the surgical care of pituitary adenomas, numerous challenges remain, such as treatment failure and recurrence. To meet these clinical challenges, there has been an enormous expansion of novel medical technologies (eg, endoscopy, advanced imaging, artificial intelligence). These innovations have the potential to benefit each step of the patient's journey, and ultimately, drive improved outcomes. Earlier and more accurate diagnosis addresses this in part. Analysis of novel patient data sets, such as automated facial analysis or natural language processing of medical records holds potential in achieving an earlier diagnosis. After diagnosis, treatment decision-making and planning will benefit from radiomics and multimodal machine learning models. Surgical safety and effectiveness will be transformed by smart simulation methods for trainees. Next-generation imaging techniques and augmented reality will enhance surgical planning and intraoperative navigation. Similarly, surgical abilities will be augmented by the future operative armamentarium, including advanced optical devices, smart instruments, and surgical robotics. Intraoperative support to surgical team members will benefit from a data science approach, utilizing machine learning analysis of operative videos to improve patient safety and orientate team members to a common workflow. Postoperatively, neural networks leveraging multimodal datasets will allow early detection of individuals at risk of complications and assist in the prediction of treatment failure, thus supporting patient-specific discharge and monitoring protocols. While these advancements in pituitary surgery hold promise to enhance the quality of care, clinicians must be the gatekeepers of the translation of such technologies, ensuring systematic assessment of risk and benefit prior to clinical implementation. In doing so, the synergy between these innovations can be leveraged to drive improved outcomes for patients of the future.

Surgical Anatomy of the Microscopic and Endoscopic Transorbital Approach to the Middle Fossa and Cavernous Sinus: Anatomo-Radiological Study with Clinical Applications

BACKGROUND

The transorbital approaches (TOAs) have acquired growing notoriety, thanks to their ability to offer alternative corridors to the skull base. However, the limited access and the unfamiliarity with this surgical perspective make recognition of key landmarks difficult, especially for less experienced surgeons. The study wants to offer a detailed description of the anatomy to comprehend the potential and limitations of TOAs.

METHODS

Measurements of the orbit region and the surrounding areas were performed on two hundred high-resolution CT scans and thirty-nine dry skulls. Five specimens were dissected to illustrate the TOA, and one was used to perform the extradural clinoidectomy. Three clinical cases highlighted the surgical applications.

RESULTS

A step-by-step description of the key steps of the TOA was proposed and a comparison with the transcranial anterior clinoidectomy was discussed. The mean work distance was 6.1 ± 0.4 cm, and the lateral working angle increased 20 ± 5.4° after removing the lateral orbital rim.

CONCLUSIONS

TOAs are indicated in selected cases when tumor involves the lateral portion of the cavernous sinus or the middle skull base, obtaining a direct decompression of the optic nerve and avoiding excessive manipulation of the neurovascular structures. Comprehension of surgical anatomy of the orbit and its surrounding structures is essential to safely perform these approaches.

History, Current Techniques, and Future Prospects of Surgery to the Sellar and Parasellar Region

The sellar and parasellar region can be affected by diverse pathologies. The deep-seated location and surrounding critical neurovascular structures make treatment challenging; there is no singular, optimal approach for management. The history and development of transcranial and transsphenoidal approaches by pioneers in skull base surgery were largely aimed at treating pituitary adenomas, which are the most common lesions of the sella. This review explores the history of sellar surgery, the most commonly used approaches today, and future considerations for surgery of the sellar/parasellar region.

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.

Intraoperative application of yellow fluorescence in resection of intramedullary spinal canal ependymoma

BACKGROUND

Spinal ependymoma is the most common intramedullary tumor in adults. This study was performed to evaluate whether intraoperative yellow fluorescence use enhances our ability to identify the tumor margin and residual tumor tissue in intramedullary spinal cord ependymoma resection. We also evaluated patients' clinical conditions at a 3-month follow-up.

METHODS

We retrospectively evaluated 56 patients with intramedullary ependymoma. Thirty minutes before anesthesia, the patients received intravenous sodium fluorescein injections. Tumor resection was performed under two illumination modes, traditional white light and yellow fluorescence, and the residual tumor tissue was detected. Magnetic resonance imaging was performed 3 months postoperatively to observe the tumor resection outcome and residual tumor tissue. The McCormick spinal cord function grade was evaluated preoperatively and 3 months postoperatively.

RESULTS

The total resection rate was 100.0% in all patients. Nine patients had no significant fluorescence imaging. After 3 months, patients with a spinal function grade of I to IV showed significant spinal function improvement. Magnetic resonance imaging showed no residual tumor tissue or recurrence.

CONCLUSION

Sodium fluorescein aids in total excision of intramedullary spinal cord ependymoma and intraoperative residual tumor tissue identification. At the 3-month follow-up, the patients' functional outcome in the fluorescein group was good.

Post-operative vision loss: analysis of 587 patients undergoing endoscopic surgery for pituitary macroadenoma

PURPOSE

Vision loss following surgery for pituitary adenoma is poorly described in the literature and cannot be reliably predicted with current prognostic models. Detailed characterization of this population is warranted to further understand the factors that predispose a minority of patients to post-operative vision loss.

MATERIALS AND METHODS

The medical records of 587 patients who underwent endoscopic transsphenoidal surgery at the Mount Sinai Medical Centre between January 2013 and August 2018 were reviewed. Patients who experienced post-operative vision deterioration, defined by reduced visual acuity, worsened VFDs, or new onset of blurry vision, were identified and analysed.

RESULTS

Eleven out of 587 patients who received endoscopic surgery for pituitary adenoma exhibited post-operative vision deterioration. All eleven patients presented with preoperative visual impairment (average duration of 13.1 months) and pre-operative optic chiasm compression. Seven patients experienced visual deterioration within 24 h of surgery. The remaining four patients experienced delayed vision loss within one month of surgery. Six patients had complete blindness in at least one eye, one patient had complete bilateral blindness. Four patients had reduced visual acuity compared with preoperative testing, and four patients reported new-onset blurriness that was not present before surgery. High rates of graft placement (10/11 patients) and opening of the diaphragma sellae (9/11 patients) were found in this series. Four patients had hematomas and four patients had another significant post-operative complication.

CONCLUSIONS

While most patients with pituitary adenoma experience favourable ophthalmological outcomes following endoscopic transsphenoidal surgery, a subset of patients exhibit post-operative vision deterioration. The present study reports surgical and disease features of this population to further our understanding of factors that may underlie vision loss following pituitary adenoma surgery. Graft placement and opening of the diaphragma sellae may be important risk factors in vision loss following ETS and should be an area of future investigation.

Management of cerebrospinal fluid leak: the importance of multidisciplinary approach

Cerebrospinal fluid (CSF) leak remains a rare condition, characterized by serious complications and potentially fatal. According to different etiologies, CSF leaks may be classified into two main categories: traumatic and spontaneous. Spontaneous fistulas seem to be mainly related to obesity and idiopathic intracranial hypertension. Diagnosis is both clinical and radiological. During the last three decades, surgical treatment has mostly shifted to endonasal endoscopic approach, which widely demonstrated to be more effective than invasive intracranial ones. Post-operative complications, long-term sequelae and hospital stay are strongly reduced thanks to endoscopic approach. The diagnosis and treatment of CSF leaks represent a difficult and challenge task. The main effort seems to be related to the precise localization of the leak. An accurate assessment of both predisposing factors and comorbidities is mandatory in case of spontaneous leaks. However, a clinical multidisciplinary evaluation as well as treatment, is essential to decrease the rate of failure of surgery. The presence of a dedicated instruments, the Skull Base Team, the knowledge of reconstructive materials and techniques represents a decisive result in therapeutical management even if for each patient an effective therapeutic algorithm can be obtained considering the correct leak detection and characteristics. In conclusion the strict teamwork with neurosurgeons, neuroradiologists, ophtalmologists will enable the development also of innovative biomaterials, which could spread and standardize multi-layer techniques, nowadays still related to surgeon preferences.

The efficacy of function-preservation in treating paranasal sinus and nasal cavity neoplasms

Background

Craniofacial resection (CFR) has been regarded as the gold standard for paranasal sinus and nasal cavity (PNSNC) neoplasms. The improvement of surgical procedures has been ongoing in recent years. We analyzed the clinical curative effects of the function-preservation therapy that was mainly using nasal endoscopic surgery along with appropriate radiotherapy and chemotherapy as applicable.

Methods

We performed a retrospective analysis of factors that influence the survival time of the 28 patients with PNSNC neoplasms who underwent nasal endoscopic surgery. All patients with tumor lesions underwent a complete resection in en bloc or piecemeal resection. Five cases did not undergo radiotherapy or chemotherapy; the remaining 23 patients had multimodality therapy.

Results

The median follow-up time was 41.5 (range = 14-97) months. The overall 3-year survival rate was 78.57% for T3 cancer and 50% for those with T4. T classification (P = 0.031) and multimodality therapy (P = 0.038) were independent prognostic factors for postoperative 3-year survival rate of patients with PNSNC neoplasms.

Conclusion

Function-preservation therapy based on the minimally invasive endoscopic resection (MIER) with appropriate adjuvant therapy not only prolonged the overall survival time but also provided an opportunity to preserve organ function at the same time, which helped to improve the patients' quality of life.

Advanced Magnetic Resonance Imaging of the Skull Base

Magnetic resonance (MR) imaging is a crucial tool for evaluation of the skull base, enabling characterization of complex anatomy by utilizing multiple image contrasts. Recent technical MR advances have greatly enhanced radiologists' capability to diagnose skull base pathology and help direct management. In this paper, we will summarize cutting-edge clinical and emerging research MR techniques for the skull base, including high-resolution, phase-contrast, diffusion, perfusion, vascular, zero echo-time, elastography, spectroscopy, chemical exchange saturation transfer, PET/MR, ultra-high-field, and 3D visualization. For each imaging technique, we provide a high-level summary of underlying technical principles accompanied by relevant literature review and clinical imaging examples.

Perioperative Considerations in Endoscopic Skull Base Surgery

Purpose of the Review

Present an overview of perioperative considerations specific to endoscopic skull base surgery necessary to maximize successful outcomes.

Recent Findings

The majority of perioperative considerations for endoscopic skull base surgery lack strong supporting evidence and frequently have varied use or implementation amongst institutions. A notable exception comes from a recent randomized controlled trial demonstrating the benefit of lumbar drainage in high-risk cerebrospinal fluid leaks.

Summary

Skull base surgeons must consider a multitude of perioperative factors. While many components of perioperative management are extrapolated from related fields such as endoscopic sinus surgery or open cranial base surgery, additional high-quality studies are needed to delineate best practices specific to endoscopic skull base surgery.