Ventral Skull Base Lesions Research Articles

Endoscopic Endonasal Skull Base Surgery Complication Avoidance: A Contemporary Review.

The endoscopic endonasal approach (EEA) provides a direct trajectory to ventral skull base lesions, avoidance of brain retraction, and clear visualization of cranial nerves as they exit skull base foramina. Despite these benefits, the EEA is not without complications. Here, we review published literature highlighting complications associated with the EEA including cerebrospinal fluid (CSF) leak, cranial nerve (CN) dysfunction, pituitary gland dysfunction, internal carotid artery (ICA) injury, infection, and others; we place special emphasis on discussing the prevention of these complications. As widespread adoption of the EEA continues, it becomes critical to educate surgeons regarding potential complications and their prevention while identifying gaps in the current literature to guide future research and advances in clinical care.

Endoscopic endonasal resection of a large tuberculum sella meningioma.

Over the past three decades, endoscopic endonasal surgery has unlocked new corridors to treat a wide spectrum of ventral skull base lesions. Tuberculum sella meningiomas represent one of the most ideal pathologies for ventral skull base access. Traditionally, these lesions were approached primarily through various subfrontal and frontal-lateral transcranial approaches that have unfortunately been shown to be associated with worsening visual decline postoperatively. The endoscopic endonasal approach is now being attempted by more surgeons and leverages an infrachiasmatic trajectory that provides direct access to the tuberculum sella where most of the vascular supply for these lesions can be taken early, facilitating more efficient surgical resection and mitigating the risk of optic nerve injury. Here we review a challenging case of a large (∼3 cm) tuberculum sella meningioma, encasing critical vessels off the circle of Willis and resected via an endoscopic endonasal approach. We discuss the technical nuances and relevant surgical anatomy of this approach and highlight important considerations in the safe and successful removal of these meningiomas. We show that certain tumors that appear to encase the supraclinoidal carotid artery can be fully resected via an endonasal approach with precise surgical technique and adequate exposure. Furthermore, this case illustrates the risk of injuring a key perforating vessel from the anterior communicating artery complex, called the subcallosal artery. Injury to this vessel is highly associated with tumors like the one presented here that extend into the suprachiasmatic space between the optic chiasm and the anterior communicating complex. Meticulous surgical dissection is required to preserve this perforating vessel as well as branches from the superior hypophyseal artery. Finally, we review our current closure techniques for these challenging approaches and discuss the use of a lumbar drain for 3 days to lower CSF leak rates.The video can be found here: https://youtu.be/mafyXi5B0MA.

Extended Endoscopic Endonasal Surgery to Ventral Skull Base Lesions

Abstract Introduction In the last two decades, Endoscopic endonasal approaches (EEAs) have undergone a significant evolution with a major shift from a transsellar approach to a variety of approaches that can directly access the midline and paramedian ventral skull base. Once the technical feasibility of any surgical approach is established; its safety (assessed through complications), and treatment outcomes (assessed through long-term follow-up) should be addressed. Aim of the Study To assess the feasibility, safety, and efficacy of EEA as a minimally invasive approach to ventral skull base lesions. Methodology and Materials this is a prospective observational study of group of 30 patients with ventral skull base lesions that were managed via endoscopic endonasal approaches. All patients’ clinical data, radiographic evaluations, procedural detail, complications, and follow-up data were recorded and analyzed. Results The mean age of patients was 50.8 years (range: 18-74 years), with a male:female ration of 1:1.72. The most commonly encountered pathological entities in the cohort was meningiomas (43.3%), pituitary adenomas (23.3%). and craniopharyngiomas (13.3%). Postoperative CSF leak was observed in 6.6% of cases and was managed successfully. There were no cases with postoperative infection in the cohort. Other procedure-related complications include transient diabetes insipidus (10%), pneumocephaly (3.3%), Syndrome of inappropriate ADH secretion (3.3%). Gross total resection was achieved in 93.3% of cases. Improvement of preoperative symptoms was recorded in 89.2% of cases. The mean follow-up duration was 17.8 ± 2.7 months. Conclusion EEAs provide direct access and better visualization to the ventral skull base without brain retraction and with minimal neurovascular manipulation, leading to less morbidity and mortality. EEA can be considered a feasible, safe, and effective tool on the armamentarium of skull base surgery. EEAs should not be considered as a replacement to the traditional transcranial approaches; rather. EEAs are deemed as a complementary route and a potential alternative to conventional skull base surgery in select cases.

Morphometry of nasopalatine line for transnasal endoscopic access to craniovertebral junction: A cadaveric study

Background and Aims: Lesions in craniovertebral junction (CVJ) are approached either through transnasal or transoral route. Endoscopic transnasal route reduces significant morbidity, and nasopalatine line (NPL) predicts the inferior-most limit of surgical dissection. The purpose of the present study was to measure the NPL in the cadavers, which is beneficial for the endoscopic transnasal anterior approach to access odontoid process and anterior CVJ, especially in surgical decompression of medulla oblongata. Materials and Methods: The present study was done on forty midline sagittal head-and-neck specimens obtained from 10% formalin-fixed cadavers in the Department of Anatomy, Rajarajeswari Medical College and Hospital, Bangalore. Using slide calipers, the hard palate line (HPL), which extends from the anterior nasal spine of maxillary bone to the posterior nasal spine of palatine bone and NPL which extends from the inferior-most point of nasal bone to the posterior nasal spine were measured. In addition, HPL was extended to the lower limit of the anterior margin of the foramen magnum, and NPL was further extended posteriorly to the ventral surface of the second cervical vertebra to know the inferior limit of transnasal endoscopic access for surgeries on ventral skull base lesions. Results: The average of HPL and its extension to foramen magnum was found to be 45.83 mm and 40.97 mm respectively. The NPL and its extension to the ventral surface of C2 vertebra were found to be 58.22 mm and 37.18 mm, respectively. Conclusion: HPL & NPL provide useful information for the neurosurgeons to access the lesions in the ventral CVJ and to achieve a good outcome.

Endoscopic Endonasal Approaches for Anterior Skull Base Meningiomas.

Anterior skull base meningiomas are a diverse group of tumors that involve different locations. The role of the expanded endoscopic transnasal approach in the management of anterior cranial fossa meningiomas has significantly changed over the past 2 decades. Patient selection is paramount to benefit from the advantages of endoscopic transnasal surgery such as direct access to ventral skull base lesions avoiding brain and brainstem retraction, early de-vascularization, removal of bone infiltrated by tumor, near-field magnification, better surgical field illumination, and minimal manipulation of neurovascular structures. Here we discuss some of the main limitations and advantages of the endoscopic transnasal approach related to patient selection, including nuances of their management, discussing preoperative imaging and planning, the surgical approach, and future perspectives in the treatment of these tumors.

Recurrence of Ventral Skull Base Lesions Attributed to Tumor Seeding: A Systematic Review

To evaluate ventral skull base lesion recurrences along surgical access pathways attributed to iatrogenic seeding. A systematic review of the literature was performed searching for recurrence of ventral skull base lesions attributed to iatrogenic implantation. Studies were assessed for level of evidence. Primary intervention, pathology, and other clinical factors were reported following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Among 69 patients with recurrent skull base lesions attributed to seeding, the most common pathologies were craniopharyngioma (52.2%), chordoma (33.3%), adenocarcinoma (4.3%), adenoid cystic carcinoma (2.9%), and squamous cell carcinoma (2.9%). Median time to recurrence was 36 months. Time to recurrence was significantly longer for craniopharyngiomas than for chordomas (42 months vs. 24 months, P ≤ 0.05). Surgical approaches included craniotomy (62.0%), transseptal (11.3%), transfacial (12.7%), and transpalatal (4.2%). Mean time to recurrence after craniotomy was 69 months. Endoscopic/endoscopic-assisted approaches were used in 5 cases (7.0%). Commonly reported recurrence sites included subarachnoid (29.6%), dura (21.1%), incision (12.7%), septum (7.0%), and ethmoid sinuses (4.2%). The potential for iatrogenic tumor seeding exists for numerous skull base lesions, most notably craniopharyngioma and chordomas. Routine surveillance may be necessary owing to significant latency intervals to ectopic recurrence. Although transnasal endoscopic techniques have been extensively employed in recent decades, only a handful of reported cases involve lesions originally treated with this approach. Further direct comparison of traditional approaches with endoscopic approaches may be invaluable in further elucidating the role of surgical technique in tumor implantation and recurrence.

Extended endoscopic endonasal approach to the ventral skull base lesions

ObjectiveWith the use of multiple endoscopic endonasal surgical corridors, extended endoscopic endonasal approaches (EEEAs) are now being used to treat a wide range of ventral skull base lesions. Our aim was to present our experience with EEEAs to the ventral skull base lesions. Patients and MethodsThe study group consisted of 106 patients (57 men and 49 women) who underwent surgery for skull base lesions using EEEAs from 2010 to 2017. The EEEA was most commonly used for giant pituitary macroadenomas, sinonasal malignancies, cerebrospinal fluid (CSF) leaks, meningiomas, craniopharyngiomas, and fibro-osseous lesions. Four different approaches were used including transtuberculum-transplanum, transethmoidal-transcribriform, transclival, and transmaxillary-transpterygoidal. ResultsThe overall gross total resection (GTR) rate for these diverse pathologies was 75.0% in 88 patients (excluding the operations performed for non-neoplastic pathologies). GTR was achieved in 100%, 77.8%, 75%, 75%, 72.2%, 62.5%, 60% of fibro-osseous lesions, giant/large pitutary adenomas, meningiomas, esthesioneuroblastomas, sinonasal malignancies, craniopharyngiomas, and chordomas, respectively. The overall rate of improvement in visual fields was 86%. The overall rate of CSF leak was 8.4%. Other surgical complications included intracerebral hematoma and tension pneumocephalus. The mortality rate was 0.9%. ConclusionEEEA is a safe, well-tolerated and effective surgical treatment modality in the management of ventral skull base lesions. It should be performed with close interdisciplinary collaboration. Appropriate case selection is mandatory. However, despite improved reconstruction techniques, postoperative CSF leakage still remains a challenge.

Pituitary and skull-base lesions and the litigious patient.

The objective of this research was to evaluate litigation relating to the diagnosis and management of pituitary and ventral skull base lesions and delineate allegations involved in the decision to pursue medicolegal proceedings. Publically available federal and court records were accessed via the Westlaw Next database. Jury verdict and settlement reports relevant to pituitary and anterior skull-base lesions were accessed, and litigation was reviewed for alleged injuries, defendant specialty, patient demographics, and other factors raised in proceedings. Of 75 cases included, 50.7% were resolved in the defendant's favor. The most frequent physician specialties cited as defendants included primary care (20%), neurosurgery (17%), and radiology (16%), while otolaryngologists were defendants in only 5% of cases. Fifty-two (69%) did not involve surgical intervention; the most common allegations in these proceedings were misdiagnosis, permanent injury (19%), requiring additional procedures as a result of misdiagnosis (17%), permanent endocrine dysfunction (14%), and visual sequelae (12%). Among surgical cases, the most common allegations raised included permanent injury (17%), postoperative complications (14%), intraoperative complications (13%), and death (10%). Among cases resolved with payment, there was no statistical difference in payment between surgical cases ($5.7M) and nonsurgical cases ($4.8M). Misdiagnosis of endocrinopathy, failure to appropriately workup patients presenting with neurologic complaints, and radiologic misdiagnosis play important roles in the pursuit of litigation in nonsurgical cases. Sustaining permanent sequelae including endocrine and visual injury play an important role in surgical cases. Postoperative management appears to play just as important a role in the decision to pursue litigation as intraoperative considerations.

Surgical nuances for nasoseptal flap reconstruction of cranial base defects with high-flow cerebrospinal fluid leaks after endoscopic skull base surgery

Extended endoscopic endonasal approaches have allowed for a minimally invasive solution for removal of a variety of ventral skull base lesions, including intradural tumors. Depending on the location of the pathological entity, various types of surgical corridors are used, such as transcribriform, transplanum transtuberculum, transsellar, transclival, and transodontoid approaches. Often, a large skull base dural defect with a high-flow CSF leak is created after endoscopic skull base surgery. Successful reconstruction of the cranial base defect is paramount to separate the intracranial contents from the paranasal sinus contents and to prevent postoperative CSF leakage. The vascularized pedicled nasoseptal flap (PNSF) has become the workhorse for cranial base reconstruction after endoscopic skull base surgery, dramatically reducing the rate of postoperative CSF leakage since its implementation. In this report, the authors review the surgical technique and describe the operative nuances and lessons learned for successful multilayered PNSF reconstruction of cranial base defects with high-flow CSF leaks created after endoscopic skull base surgery. The authors specifically highlight important surgical pearls that are critical for successful PNSF reconstruction, including target-specific flap design and harvesting, pedicle preservation, preparation of bony defect and graft site to optimize flap adherence, multilayered closure technique, maximization of the reach of the flap, final flap positioning, and proper bolstering and buttressing of the PNSF to prevent flap dehiscence. Using this technique in 93 patients, the authors' overall postoperative CSF leak rate was 3.2%. An illustrative intraoperative video demonstrating the reconstruction technique is also presented.

Endoscopic endonasal approach for resection of ventral skull base keratinaceous cysts

Epidermoid and dermoid cysts are uncommon entities that belong in the differential diagnosis of ventral skull base lesions. The endoscopic endonasal approach is an attractive option for management of these lesions with limited morbidity. The clinical characteristics and management course from our experience is reviewed along with the relevant literature. A prospective database of endoscopic endonasal skull base cases performed since 2003 at a tertiary referral center was reviewed for cases involving keratinaceous lesions. Data on the pathology, radiology and management of the disease was reviewed. A search of pertinent literature using Medline was performed to complement the discussion. Three cases of intracranial keratinaceous cysts successfully managed with the endoscopic endonasal approach. All cases presented with headache, and 1 case presented with bitemporal hemianopsia. Characteristic appearance on magnetic resonance imaging was seen in each case. All lesions were intradural with variable involvement of the suprasellar, prepontine, and premedullary cisterns. Total resection was achieved in 2 cases and near total resection in 1 case. Postoperative cerebrospinal fluid leak occurred in one case, which was controlled after revision surgery using the "gasket-seal" technique. There were no cranial nerve palsies or vascular events. The endoscopic endonasal approach allows the rhinologic surgeon to access the ventral midline skull base for the successful management of keratinaceous cysts without major complications.

The Posteriorly Pedicled Middle Turbinate Flap for Dural Reconstruction After Skull Base Surgery

Background: The expanded endonasal approach provides a minimally invasive, transnasal corridor for the surgical treatment of ventral skull base lesions. Vascularized reconstruction with axial flaps reliably recreates a hardy barrier between the intracranial and sinonasal cavities. The nasoseptal flap, the workhorse for endonasal reconstruction, is not always available. The middle turbinate mucoperiosteal flap may provide an alternative local endonasal flap for the reconstruction of small dural defects.

Expanded endonasal approach: a fully endoscopic completely transnasal resection of a skull base arteriovenous malformation

Vascular lesions with an intraosseus nidus involving the skull base are uncommon and challenging [Gianoli GJ, Amedee RG Vascular malformation of the sphenoid sinus. Ear Nose Throat J. 70:373-375;(1991), Malik GM, Mahmood A, Mehta BA Dural arteriovenous malformation of the skull base with intraosseous vascular nidus. Report of two cases. J. Neurosurg 81:620-623;(1994)]. We present a pediatric patient, with a life-threatening arteriovenous malformation (AVM) of the sphenoid sinus, clivus, and ventral skull base, who failed routine multimodality management of AVMs. An entirely transsphenoidal fully endoscopic resection was used to resect this ventral cranial base AVM with an intraosseus nidus located in the clivus. A 4-year-old female presented with recurrent, life-threatening hemorrhages from a clival and ventral skull base AVM of the entire clivus and ventral skull base. The patient had been temporized from the age of 2-4 years with multiple internal and external carotid arterial particulate and alcohol embolizations, including both external and internal carotid artery embolizations, intracranial ligation of the right internal carotid artery, and gamma knife irradiation. Despite these multiple interventions, the patient had persistent, life-threatening hemorrhages from arterial recanalization and recruitment requiring intubation, tracheostomy, and nasopharyngeal packing. The patient underwent a three-stage surgical intervention to resect the AVM. An open subfrontal approach, as the first procedure, provided minimal access to the feeding vessels and was therefore aborted. A two-stage image-guided fully endoscopic approach via a sublabial midface approach without external incisions was performed. Postoperative angiography revealed minimal residual shunting in the pharynx and cavernous sinus. The patient has been free of significant hemorrhages over the past three years. Technological advances in endoscopic surgery and image guidance are now allowing for purely endoscopic surgical treatment of previously unresectable lesions with acceptable morbidity. We report the successful and safe resection of a ventral cranial base AVM via a fully endoscopic approach. This paper reports the first AVM with a purely intraosseus nidus of the ventral skull base and demonstrates the ability to deal with complex ventral skull base lesions using a fully endoscopic transsphenoidal technique.