Managing Arterial Injury in Endoscopic Skull Base Surgery: Case Series and Review of the Literature

Lateral Transorbital Endoscope-Assisted Approach to the Cavernous Sinus

BACKGROUND AND OBJECTIVES

Surgical access to the cavernous sinus (CS) poses a unique challenge to the neurosurgeon given the concentration of delicate structures in the confines of a very small anatomic space. The lateral transorbital approach (LTOA) is a minimally invasive, keyhole approach that can provide direct access to the lateral CS.

METHODS

A retrospective review of CS lesions treated by a LTOA at a single institution was performed between 2020 and 2023. Patient indications, surgical outcomes, and complications are described.

RESULTS

Six patients underwent a LTOA for a variety of pathologies including a dermoid cyst, schwannoma, prolactinoma, craniopharyngioma, and solitary fibrous tumor. The goals of surgery (ie, drainage of cyst, debulking, and pathological diagnosis) were achieved in all cases. The mean extent of resection was 64.6% (±34%). Half of the patients with preoperative cranial neuropathies (n = 4) improved postoperatively. There were no new permanent cranial neuropathies. One patient had a vascular injury repaired endovascularly with no neurological deficits.

CONCLUSION

The LTOA provides a minimal access corridor to the lateral CS. Careful case selection and reasonable goals of surgery are critical to successful outcome.

Internal carotid artery injury during endoscopic endonasal surgery for skull base pathologies: an institutional incidence, management, and outcome

BACKGROUND

Endoscopic endonasal surgery (EES) has become a popular approach to deal with skull base pathologies. The most catastrophic intra-operative complication of EES is internal carotid artery (ICA) injury. We aim to discuss and introduce our institutional experience with ICA injury during EES.

METHODS

A retrospective review of patients who underwent EES from 2013 to 2022 was performed to determine the incidence and outcomes of intraoperative ICA injuries.

RESULTS

There were six patients (0.56%) with intraoperative ICA injury in our institution during the last 10 years. Fortunately, there was no morbidity or mortality in our patients with intraoperative ICA injuries. The sites of injury were equally in paraclival, cavernous sinus, and preclinoidal segments of ICA.

CONCLUSION

Primary prevention is the best solution for this condition. Regarding our institutional experience, the best option for primary management just after an injury is packing the surgical site. In cases where packing is not enough for temporary control of bleeding, common carotid artery occlusion should be considered. We have presented our experience and reviewed previous studies regarding different treatments and suggested our intra and post-operative management algorithm.

Endoscopic endonasal surgical anatomy of the optic canal: key anatomical relationships between the optic nerve and ophthalmic artery

PURPOSE

A detailed understanding of the neurovascular relationships between the optic nerve (ON) and the ophthalmic artery (OA) in the optic canal (OC) is paramount for safe surgery. We focused on the neurovascular anatomy of this area from both an endoscopic endonasal and transcranial trajectories to compare the surgical exposures and perspectives offered by these different views and provide recommendations to increase the intraoperative safety.

METHODS

Twenty sides of ten formalin-fixed, latex-injected head specimens were utilized. The surgical anatomy and anatomical relationships of the OA in relationship to the ON along their intracranial and intracanalicular segments was studied from endoscopic endonasal and transcranial perspectives.

RESULTS

Three types of OA-ON relationships at the origin of the OA were identified: inferomedial (type 1, 35%), inferior (type 2, 55%), and inferolateral (type 3, 10%). The endoscopic endonasal trajectory offers an inferomedial perspective of the ON-OA neurovascular complex, in which the OA, especially when located inferomedially, is first encountered. When comparing with the transcranial view, all OA were covered by the nerve, type 1 was located below the medial third, type 2 below the middle third, and type 3 below the lateral third of the OC. The mean extension of the intracanalicular portion of both OA and ON was 8.9 mm, while the intracranial portion of the OA and ON were 9.3 mm and 12.4 mm, respectively. The OA, endoscopically, is located within the inferior half of the OC, and occupies 39%, 43%, and 42% of the OC height at its origin, mid, and end points, respectively. The mean distance between the superior margin of the OC at its origin and superior margin of the OA is 1.4 mm.

CONCLUSIONS

Detailed anatomical understanding of the OC, and the ON and OA at their intracranial and intracanalicular segments is paramount to safe surgery. When opening the OC dura endoscopically, our results suggest that a medial incision along the superior third of the OC with a proximal to distal direction is recommended to avoid injury of the OA.

Vascular anomalies in patients with growth hormone-secreting pituitary adenomas: illustrative case report and systematic review of the literature

PURPOSE

Endonasal resection is the first-line treatment for patients harboring growth hormone (GH)-secreting pituitary adenomas. The complexity of the parasellar neurovascular structures makes pre-operative diagnostic imaging essential to understanding the anatomy of this region. We aimed to describe vascular anomalies in acromegalic patients and emphasize their relevance for surgery and preoperative planning.

METHODS

A systematic review following the PRISMA statement was performed in July 2021.

RESULTS

Thirty-three studies were evaluated. Elevated GH and insulin-like growth factor-1 (IGF-1) levels are linked to the occurrence of cardiovascular risk factors. This is attributed to endothelial dysfunction, mainly caused by changes in flow-mediated dilatation (FMD), which is probably the main cause of vascular anomalies in acromegaly. The occurrence of protrusions of the internal carotid artery (ICA) (35-53%), a narrow intercarotid distance, and an asymmetrical course was described. In 13-18% of acromegalic patients, the presence of an intracerebral aneurysm could be reported (incidence in the general population:0.8-1.3%). The selected studies were however performed with a small patient sample (range:1-257). We present a case report of a 57y/o male patient with anomalies of the ICA ("kissing carotid arteries") harboring a GH-secreting adenoma, which was resected via an endoscopic endonasal approach.

CONCLUSIONS

There is an association between acromegaly and endothelial dysfunction, which increases cardiovascular risk factors and vascular anomalies. Preoperative vascular imaging, e.g., CT angiography, should be implemented as a standard to identify patients at risk and estimate surgical morbidity. However, no evidence-based recommendations exist so far, so future studies are necessary.

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.

Destructive strategies in treating cerebrovascular pathology: Review and treatment algorithm

The goal of cerebrovascular pathology treatment is most often to angiographically eradicate a lesion with the lowest probability of morbidity. Destructive strategies using parent vessel occlusion are less commonly considered in the modern era. We review principles of parent vessel occlusion for treatment of cerebrovascular pathology and select cases to demonstrate these principles. Many common cerebrovascular conditions have been safely and effectively treated with destructive strategies including intracranial aneurysms, traumatic craniocervical vascular injuries, and oncologic indications such as carotid blowout. Avoiding procedural morbidity in these procedures involves assessment of collaterals distal to a planned parent vessel occlusion, determination of this arterial segment's eloquence, prevention of distal migration of endovascular devices or thrombus, and prevention of stump emboli. An algorithm for case selection and method of destructive technique versus a reconstructive approach can be used. Destructive strategies for treating cerebrovascular pathology are still relevant and can be applied safely in appropriately selected cases.

Carotid Artery-Cavernous Segment Injury during an Endoscopic Endonasal Surgery: A Case Report and Literature Review of the Overlooked Option for Surgical Trapping in the Hyperacute Phase

Internal carotid artery (ICA) injury is a catastrophic complication of endoscopic endonasal surgery (EES). However, its standard management, emergent endovascular treatment, may not always be available, and the transnasal approach may be insufficient to achieve hemostasis. A 44-year-old woman with pituitary adenoma underwent EES complicated with the ICA cavernous segment injury (CSI). In urgent intraoperative angiogram, a good collateral flow from the contralateral carotid circulation was observed. Due to the unavailability of intraoperative embolization, emergent surgical trapping was performed by combined transcranial and cervical approach. The patient recovered but later developed a giant cavernous pseudoaneurysm. During the pseudoaneurysm embolization, ICA was directly accessed via a 1.7-F puncture hole using a bare microcatheter technique. Then, both the aneurysm and parent artery were obliterated with coils. At the 4-year follow-up, the patient was asymptomatic without a residual tumor. To our knowledge, this is the first case of ICA-CSI during EES successfully treated with ICA trapping as a lifesaving urgent surgery that achieved a complete recovery after a pseudoaneurysm embolization. Although several studies reported that EES-related ICA-CSIs with percutaneous carotid artery access, neither our surgical salvage technique nor our carotid access and tract embolization techniques were previously described.

Blood supply to the corticospinal tract: A pictorial review with application to cranial surgery and stroke

The corticospinal tract (CST) is the main neural pathway responsible for conducting voluntary motor function in the central nervous system. The CST condenses into fiber bundles as it descends from the frontoparietal cortex, traveling down to terminate at the anterior horn of the spinal cord. The CST is at risk of injury from vascular insult from strokes and during neurosurgical procedures. The aim of this article is to identify and describe the vasculature associated with the CST from the cortex to the medulla. Dissection of cadaveric specimens was carried out in a manner, which exposed and preserved the fiber tracts of the CST, as well as the arterial systems that supply them. At the level of the motor cortex, the CST is supplied by terminal branches of the anterior cerebral artery and middle cerebral artery. The white matter tracts of the corona radiata and internal capsule are supplied by small perforators including the lenticulostriate arteries and branches of the anterior choroidal artery. In the brainstem, the CST is supplied by anterior perforating branches from the basilar and vertebral arteries. The caudal portions of the CST in the medulla are supplied by the anterior spinal artery, which branches from the vertebral arteries. The non-anastomotic nature of the vessel systems of the CST highlights the importance of their preservation during neurosurgical procedures. Anatomical knowledge of the CST is paramount to clinical diagnosis and treatment of heterogeneity of neurodegenerative, neuroinflammatory, cerebrovascular, and skull base tumors.

Assessment of Arterial Configurations of the Suprachiasmatic Region from the Endoscopic Endonasal Perspective: A Cadaveric Anatomical Study

BACKGROUND

Endoscopic endonasal surgery has proved to offer a practical route to treat suprasellar lesions, including tumors and vascular pathologies. Understanding the different configurations of the anterior cerebral communicating artery (ACoA) complex (ACoA-C) is crucial to properly navigate the suprachiasmatic space and decrease any vascular injury while approaching this region through an endonasal approach.

METHODS

An endoscopic endonasal transplanum-transtubercular approach was performed on 36 cadaveric heads (72 sides). The variations of the ACoA-C and feasibility of reaching its different components were analyzed. The surgical area exposure of the lamina terminalis was also quantified before and after mobilization of the ACoA-C.

RESULTS

The typical ACoA-C configuration was found in 41.6% of specimens. The following 2 main variations were identified: accessory anterior cerebral artery segment 2 (5, 13.9%) and common trunk of anterior cerebral artery with absence of ACoA (5, 13.9%). Of 101 recurrent arteries of Heubner, 96 (95.0%) were identified within 4 mm proximal or distal to the ACoA. The mean lamina terminalis exposure area was 33.1 ± 16.7 mm², which increased to 59.9 ± 11.9 mm² after elevating the ACoA.

CONCLUSIONS

A considerable amount of variation of the ACoA-C can be found through an endoscopic endonasal transplanum-transtubercular approach. These configurations determine the feasibility of lamina terminalis exposure and the complexity of reaching the ACoA. Assessment of ACoA morphology and its adjacent structures is crucial while approaching the suprachiasmatic through a transnasal corridor.

When is a multidisciplinary surgical approach required in sinonasal tumours with cranial involvement?

The term “sinonasal tumours” includes a large spectrum of diseases, which are characterized by heterogeneous biological behavior and prognosis, and located in a critical anatomic area. Diagnosis and treatment of sinonasal tumours require the contribution of different disciplines. A narrative review was performed to highlight the role of surgeons in contributing to a multidisciplinary approach to sinonasal tumours. Diagnosis and staging of sinonasal tumours is challenging and requires collaboration between surgeons, radiologists, and pathologists. The identification and management of critical extensions (orbital or intracranial encroachment, vascular abutment or encasement) is fundamental for successful treatment. Most cases of advanced sinonasal tumours can undergo surgical intervention by an adequately trained otorhinolaryngological team. The contribution of neurosurgeons and oculoplastic surgeons is required in selected scenarios. In rare circumstances, multidisciplinary reconstructive strategies can be indicated for complex tissue defects. Furthermore, a multidisciplinary approach is pivotal in the management of perioperative complications. While surgery remains the mainstay of treatment, the role of non-surgical adjuvant or even exclusive treatments is constantly expanding.

Carotid Sacrifice via Endonasal Clipping to Treat Carotid Injury in Extended Endoscopic Endonasal Surgery

ABSTRACT

Internal carotid artery (ICA) injury is a rare but disastrous complication during extended endoscopic endonasal surgery. The method of ICA sacrifice via endonasal clipping has only been reported in a few cases to treat ICA injury. To provide some technical experience of this method, here the authors present 2 cases of ICA injury during extended endoscopic endonasal surgery with 2-year follow-up. The 2-nostrils/4-hands technique was used to control the active bleeding. Based on the good collateral circulation status and the normal results of intraoperative electrophysiological monitoring, we sacrificed the injured ICAs via endonasal clipping. Both cases had a satisfying tumor resection rate and a good clinical outcome.

Identifying Best Practices for Managing Internal Carotid Artery Injury During Endoscopic Endonasal Surgery by Consensus of Expert Opinion

BACKGROUND

Injury to the internal carotid artery (ICA) is a potentially devastating complication of endoscopic endonasal surgery (EES) that as many as 20% of skull base surgeons will experience at least once during their careers. Managing these injuries is difficult given the small operative field and poor visibility created by high-flow hemorrhage, and, at present, there is no consensus regarding best practices.

OBJECTIVE

This study seeks to consolidate the practices and opinions of experienced skull base surgeons from high-volume tertiary care centers into a single consensus statement regarding the best practices for managing ICA injuries during EES.

METHODS

A panel of 23 skull base surgeons (15 neurosurgeons and 8 otolaryngologists) completed a 3-round Delphi survey that assessed experiences and opinions regarding various aspects of ICA injury management. Mean (SD) years since fellowship completion was 15.6 (8.1) and all but 3 surgeons had experienced an ICA injury at least once.

RESULTS

The final consensus statement included 36 guidelines all of which were grouped under 1 of 4 categories: 11 statements concerned preoperative management and equipment for high-risk patients; 14 statements concerned hemorrhage control; 4 statements concerned definitive management; 7 statements concerned pharmacologic treatment, blood pressure, and neurophysiologic monitoring.

CONCLUSIONS

There are numerous decisions that a surgeon must make when facing a carotid artery injury. In our estimation, many questions can be grouped under 1 of the 4 categories outlined in our consensus statement and can be addressed by these findings.

Basilar Artery Injury During Endonasal Surgery: Stepwise to Control Bleeding

BACKGROUND

Intraoperative injury during endoscopic endonasal surgery of the carotid artery has been previously described in the literature. However, the accidental damage of the basilar artery in such scenario is not defined.

OBJECTIVE

To define the protocol of action for massive bleeding from an artery in the posterior fossa.

METHODS

The reported patient was diagnosed with a partially calcified clival chordoma featured by a huge intradural component. An endoscopic endonasal transpterygoid transclival approach was selected for the treatment of this tumor. During the surgical procedure, the basilar artery injury was injured, causing intense bleeding. We present and discuss the surgical maneuvers that could save a patient's life after this dramatic complication.

RESULTS

Different techniques were performed in order to control the massive bleeding, including injection of hemotastic matrix with thrombin (Floseal©), bipolar coagulation, and vessel reconstruction by means of a vascular clip. Finally, an autologous muscle graft reinforced with an overlying fibrin sealant patch (Tachosil©) was chosen and was an effective technique. Afterwards, the patient was treated with a flow diverter device to occlude an iatrogenic pseudoaneurysm. A monoplegia of the right upper limb was the only remarkable sequel 6 mo after surgery.

CONCLUSION

The muscle graft together with the coordinated action with interventional neuroradiology for the reconstruction of the vessel are possibly the best options to try to preserve the neurological function. In such a scenario, the assumption of potential ischemic events prevails over the intraoperative death of the patient.

Utility of 7 Tesla MRI for Preoperative Planning of Endoscopic Endonasal Surgery for Pituitary Adenomas

Objective  There is increasing interest in investigating the utility of 7 Tesla (7 T) magnetic resonance imaging (MRI) for imaging of skull base tumors. The present study quantifies visualization of tumor features and adjacent skull base anatomy in a homogenous cohort of pituitary adenoma patients. Methods  Eighteen pituitary adenoma patients were scanned at 7 T in this prospective study. All patients had reference standard-of-care clinical imaging at either 3 T (7/18, 39%) or 1.5 T (11/18, 61%). Visualization of tumor features and conspicuity of arteries and cranial nerves (CNs) was rated by an expert neuroradiologist on 7 T and clinical field strength MRI. Overall image quality and severity of image artifacts were also characterized and compared. Results  Ability to visualize tumor features did not differ between 7 T and lower field MRI. Cranial nerves III, IV, and VI were better detected at 7 T compared with clinical field strength scans. Cranial nerves III, IV, and VI were also better detected at 7 T compared with only 1.5 T, and CN III was better visualized at 7 T compared with 3 T MRI. The ophthalmic arteries and posterior communicating arteries (PCOM) were better detected at 7 T compared with clinical field strength imaging. The 7 T also provided better visualization of the ophthalmic arteries compared with 1.5 T scans. Conclusion  This study demonstrates that 7 T MRI is feasible at the skull base and identifies various CNs and branches of the internal carotid artery that were better visualized at 7 T. The 7 T MRI may offer important preoperative information that can help to guide resection of pituitary adenoma and reduce operative morbidity.

Utility of intraoperative ultrasonography for resection of pituitary adenomas: a comparative retrospective study

BACKGROUND

The evolution of pituitary surgery has made it a safe and effective form of treatment; however, risks of inadequate tumor resection, cerebrospinal fluid (CSF) leak, pituitary dysfunction, and vascular injury still exist. The use of intraoperative ultrasonography (IOUS) in pituitary surgery has been well described. Recent advancements in ultrasound technology have allowed for expanded utility as described here.

METHODS

A retrospective review was performed between January 2016 and December 2019. One hundred thirty-eight patients (mean age 53.7 years, 47% females) were identified undergoing transsphenoidal surgery for pituitary tumors. Thirty-four patients had IOUS performed using a side-firing ultrasound probe, while 104 did not. Data was analyzed for preoperative (demographics, clinical, and radiographic features), perioperative (blood loss, operative time), and postoperative (complications, length of stay, hormone remission, and extent of resection) outcomes.

RESULTS

There were no significant differences in patient age, gender, tumor volume, Knosp grade, and hormone-secreting status between the two groups. Patients treated using IOUS had significantly higher rates of gross total resection (79% vs. 44%, p = 0.0008), shorter operative times (74 vs. 146 min, p < 0.0001), lower blood loss (119 vs. 284 cc, p < 0.0001), and hospital stays (2.9 vs. 4.2 days, p = 0.001). Overall complication rates were lower in the IOUS group compared to standard pituitary surgery but did not reach significance.

CONCLUSIONS

Recent improvements in ultrasound technology have allowed for miniaturization of probes capable of delivering high-resolution images. The use of IOUS in transsphenoidal pituitary surgery may significantly increase rates of gross total resection, while decreasing blood loss, hospital LOS, and operative time.

Endoscopic technology and repair techniques

In this chapter, we describe advances in endoscopic endonasal surgery that have impacted skull base meningioma surgery. After reviewing the technical innovations in endoscopy, we describe the advances as they relate to each surgical step. We discuss preoperative planning and approach and the utility of neuronavigation and neuromonitoring. We then discuss endoscopic instrumentation, technology for tumor debulking (ultrasonic aspirators, radiofrequency ablators, suction debriders), and hemostatic agents as they relate to tumor resection and hemostasis. In the end, we discuss techniques of skull base reconstruction and closure (nasoseptal flap, gasket seal and bilayer button).

Repair of internal carotid artery injury with aneurysm clip during endoscopic endonasal surgery: illustrative case

BACKGROUND

One of the most feared and dangerous scenarios that can appear during an endoscopic endonasal surgery (EES) is the iatrogenic injury of the internal carotid artery (ICA). Several methods, along with a variety of outcomes, have been described to deal with this complication. To the authors’ knowledge, this is the first report on the use of a Yasargil-type aneurysm clip to solve an ICA injury, preserving the artery’s patency and having a long-term follow-up. The authors discuss the advantages and disadvantages of other vessel preservation techniques compared with clipping.

OBSERVATIONS

A visually impaired 56-year-old woman was diagnosed with a giant nonfunctional pituitary tumor that invaded the sphenoidal sinus, anterior and posterior ethmoidal cells, and both cavernous sinuses, with suprasellar extension and optochiasmatic compression. The patient underwent EES, and during the final resection phase her left ICA was injured, with massive hemorrhage.

LESSONS

ICA injury during endoscopic skull base surgery carries high mortality and morbidity; it is essential to maintain carotid flow when possible to avoid short-term and long-term consequences. There are several techniques depicted in the literature to deal with this situation. The authors report the use of a Yasargil mini-clip to deal with the injury for a positive outcome: primary hemostasis, vessel preservation, and no postoperative complications.

Treatment of an anterior cerebral artery pseudoaneurysm secondary to a transsphenoidal surgery using stent-assisted coiling

Background:

Injury of the internal carotid artery (ICA) during transsphenoidal surgery (TSS) is a rare but critical complication. There are several reports on endovascular treatment of ICA injury during TSS. With the recent flourishing of extended TSS, injuries to the distal arteries such as the anterior cerebral artery (ACA) are more likely to occur.

Case Description:

In the present case, we report a pseudoaneurysm of the right ACA due to injury during extended TSS for aggressive prolactinoma. Due to the absence of collateral vessels, the pseudoaneurysm had to be obliterated while preserving the parent artery. Hence, we decided to treat the pseudoaneurysm using stent-assisted coiling (SAC). The pseudoaneurysm was completely obliterated and he was discharged without any complications.

Conclusion:

To the best of our knowledge, this is the first case in which an ACA pseudoaneurysm caused by injury during the TSS was treated with SAC and the parent artery was preserved.

Classification of internal carotid artery injuries during endoscopic endonasal approaches to the skull base

Background:

Internal carotid artery (ICA) injuries are a major complication of endoscopic endonasal approaches (EEAs), which can be difficult to manage. Adding to the management difficulty is the lack of literature describing the surgical anatomical classification of these types of injuries. This article proposing a novel classification of ICA injuries during EEAs.

Methods:

The classification of ICA injuries during EEAs was generated from the review of the literature and analysis of the main author observation of ICA injuries in general. All published cases of ICA injuries during EEAs in the literature between January 1990 and January 2020 were carefully reviewed. We reviewed all patients’ demographic features, preoperative diagnoses, modes of injury, cerebral angiography results, surgical and medical management techniques, and reported functional outcomes.

Results:

There were 31 papers that reported ICA injuries during EEAs in the past three decades, most studies did not document the type of injury, and few described major laceration type of it. From that review of the literature, we classified ICA injuries into three main categories (Types I-III) and six sub-types. Type I is ICA branch injury, Type II is a penetrating injury to the ICA, and Type III is a laceration of the ICA wall. The functional neurological outcome was found to be worse with Type III and better with Type I.

Conclusion:

This is a novel classification system for ICA injuries during EEAs; it defines the patterns of injury. It could potentially lead to advancements in the management of ICA injuries in EEAs and facilitate communication to develop guidelines.

Use of Adenosine to Facilitate Localization and Repair of Internal Carotid Artery Injury during Skull Base Surgery: A Case Report and Literature Review

BACKGROUND

Internal carotid artery (ICA) injuries represent a rare, potentially fatal complication of endoscopic endonasal skull base surgery (EESBS). The use of adenosine to induce transient hypotension and facilitate management of high-flow, high-pressure arterial lesions has been well-documented in neuro-endovascular literature. A similar setting in which adenosine-induced hypotension may prove beneficial is during the management of major vascular injury encountered during EESBS.

METHODS

A case of ICA injury and subsequent repair during EESBS is presented.

RESULTS

A 74-year-old female underwent endoscopic transsphenoidal resection for a recurrent pituitary adenoma. During suprasellar resection, the right cavernous ICA was inadvertently injured resulting in brisk bleeding. Immediate vascular tamponade was applied, and a crushed muscle graft was obtained. Two intravenous doses of adenosine were administered in quick succession to produce transient hypotension and facilitate repair of the injury with the graft. Neurovascular imaging revealed a small pseudoaneurysm which remained stable throughout the postoperative course. The patient underwent definitive stent embolization of the pseudoaneurysm 1 month following discharge.

CONCLUSION

Prompt repair of ICA injury during EESBS is crucial, but often limited by poor visualization. Adenosine-induced hypotension has demonstrated great efficacy as an adjuvant in neurovascular clipping of intracranial aneurysms and remains a valuable tool for the endoscopic skull-base surgeon as well. In cases with high risk for ICA injury, adenosine should be readily available.

Internal carotid artery injury in the endoscopic transsphenoidal surgery for pituitary adenoma: an uncommon case and literature review

Complications of the transsphenoidal surgery (TSS) for pituitary adenoma (PA) include vascular injury, nerve injury and nervous system infection. Among these, the consequences of internal carotid artery (ICA) injury are the most serious, and its mortality and disability rates are very high. The TSS was used in 889 patients with PA, among which there was 1 case of ICA injury. In this uncommon case of bromocirptine-resistant macro-prolatinoma, the patient had received an ultrahigh dose of oral bromocriptine for almost three years and was intraoperatively found to have a tenacious tumor texture and close adhesion of the tumor capsule to the ICA. Resection of the tumor capsule required excessive force, resulting in the rupture at the A1 origin of the left ICA. Endovascular balloon occlusion was used after urgent angiography. The patient died in two weeks even with intensive treatment. Although the underlying mechanism is still obscure, bromocriptine-inducing tumor fibrosis in PA is relatively common. For these patients with excessive dose of bromocriptine, tumor fibrosis and ICA injury should be seriously considered and performing a complete preoperative imaging evaluation to achieve accurate intraoperative positioning and carefully performing the operation are needed to preventing ICA injury. In some cases, resection of the tumor pseudocapsule should not be forced to avoid ICA injury.

Anatomic Nuances of the Ophthalmic Artery Origin from a Ventral Viewpoint: Considerations and Implications for Endoscopic Endonasal Surgery

BACKGROUND

The origin of the ophthalmic artery is within the surgical field of endoscopic endonasal approaches (EEAs) to the suprasellar and parasellar regions. However, its anatomy from the endoscopic point-of-view has not been adequately elucidated.

OBJECTIVE

To highlight the anatomy of the ophthalmic artery origin from an endoscopic endonasal perspective.

METHODS

The origin of the ophthalmic artery was studied bilaterally under endoscopic visualization, after performing transplanum/transtubercular EEAs in 17 cadaveric specimens (34 arteries). Anatomic relationships relevant to surgery were evaluated. To complement the cadaveric findings, the ophthalmic artery origin was reviewed in 200 "normal" angiographic studies.

RESULTS

On the right side, 70.6% of ophthalmic arteries emerged from the superior aspect, while 17.6% and 11.8% emerged from the superomedial and superolateral aspects of the intradural internal carotid artery, respectively. On the left, 76.5%, 17.6%, and 5.9% of ophthalmic arteries emerged from the superior, superomedial, and superolateral aspects of the internal carotid, respectively. Similar findings were observed on angiography. All ophthalmic arteries emerged at the level of the medial opticocarotid recess. Overall, 47%, 26.5%, and 26.5% of ophthalmic arteries (right and left) were inferolateral, inferior, and inferomedial to the intracranial optic nerve segment, respectively. On both sides, the intracranial length of the ophthalmic artery ranged from 1.5 to 4.5 mm (mean: 2.90 ± standard deviation of 0.74 mm).

CONCLUSION

Awareness of the endoscopic nuances of the ophthalmic artery origin is paramount to minimize the risk of sight-threatening neurovascular injury during EEAs to the suprasellar and parasellar regions.

Artery of Percheron and Endoscopic Endonasal Surgery: Case Report and Review of the Literature

Artery of Percheron (AOP) is a rare anatomical variant in which a single perforating artery arising from the P1 segment of the posterior cerebral artery supplies paramedian thalami and rostral midbrain. The occlusion of AOP produces bilateral thalamic ischemia and may be a rare complication in relation to an extended endoscopic endonasal approach. We report the case of a patient who developed AOP damage during endoscopic endonasal surgery (EES); to our knowledge, this complication has been previously reported only in one case, in relation to a second surgery. We also review the anatomical variants in thalamic vascularization and the factors that may be involved in this complication. A 52-year-old female underwent an extended endoscopic endonasal approach with intraoperative neurophysiological monitoring. In the postoperative period, she presented with a decreased level of consciousness and bilateral mydriasis. Magnetic resonance imaging showed rostral midbrain and paramedian thalami ischemia congruent with AOP infarction. AOP infarction may be associated with extended EES when treating lesions with retrosellar extension. Every effort should be made to preserve the small perforating arteries. Intraoperative neurophysiological monitoring of the motor and sensory pathways may not detect damage to the AOP.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

Visual Evoked Potentials and Intraoperative Awakening in Ophthalmic Artery Sacrifice During Aneurysm Clipping: 2 Cases and Literature Review

BACKGROUND

Complete aneurysm obliteration is the goal of aneurysm treatment. In selected cases, a neck remnant may be left to preserve a critical branch. Literature on ophthalmic artery sacrifice in the treatment of cerebral aneurysms and subsequent risk of vision loss is limited.

CASE DESCRIPTION

Herein, we describe 2 cases where the ophthalmic artery originated from the aneurysm dome, resulting in a situation where we either incompletely obliterate the aneurysm or sacrifice the ophthalmic artery in order to completely clip the lesion, risking visual function.

CONCLUSIONS

We report for the first time the use of visual evoked potential monitoring and intraoperative awakening to test visual function following intentional ophthalmic artery sacrifice to demonstrate gross vision preservation.

Management of arterial injuries in endoscopic endonasal approaches

This is the case of a 76-year-old woman presenting with progressive right vision loss consisting of a right eye temporal field cut and severe visual acuity loss. An MRI was performed showing a suprasellar mass for which she had been referred to our center for an endoscopic endonasal approach. The tumor was found to be densely adherent to adjacent structures, and an ophthalmic artery and A1-A2 junction injury were sustained during resection. The management of intraoperative vascular injuries is described. The video can be found here: https://youtu.be/JJY6nYKTCSg.

A modified endovascular treatment protocol for iatrogenic internal carotid artery injuries following endoscopic endonasal surgery

OBJECTIVE

Internal carotid artery (ICA) injuries during endoscopic endonasal surgery (EES) are catastrophic complications. Alongside the advancements in medical instrumentation and material, there is a need to modify previous treatment modalities and principles.

METHODS

A retrospective review of 3658 patients who underwent EES performed at the authors' institution between January 2012 and December 2017 was conducted. Ultimately, 20 patients (0.55%) with ICA injury following EES were enrolled for analysis. Data collection included demographic data, preoperative diagnosis, injury setting, repair method, and immediate and follow-up angiographic and clinical outcomes.

RESULTS

Among the 20 patients, 11 received immediate endovascular therapy and 9 were treated only with packing. Of the 11 patients who received endovascular treatment, 6 were treated by covered stent and 5 by parent artery occlusion (PAO). The preservation rate of injured ICA increased from 20.0% (1 of 5) to 83.3% (5 of 6) after the Willis covered stent graft became available in January 2016. Of the 20 patients in the study, 19 recovered well and 1 patient-who had a pseudoaneurysm and was treated by PAO with a detachable balloon-suffered epistaxis after the hemostat in her nasal cavity was removed in ward, and she died later that day. The authors speculated that the detachable balloon had shifted to the distal part of ICA, although the patient could not undergo a repeat angiogram because she quickly suffered shock and could not be transferred to the catheter room. After the introduction of a hybrid operating room (OR), one patient whose first angiogram showed no ICA injury was found to have a pseudoaneurysm. He received endovascular treatment when he was brought for a repeat angiogram 5 days later in the hybrid OR after removing the hemostat in his nasal cavity. Of the 4 surviving patients treated with PAO, no external carotid artery-ICA bypass was required. The authors propose a modified endovascular treatment protocol for ICA injuries suffered during EES that exploits the advantage of the covered stent graft and the hybrid OR.

CONCLUSIONS

The endovascular treatment protocol used in this study for ICA injuries during EES was helpful in the management of this rare complication. Willis stent placement improved the preservation rate of injured ICA during EES. It would be highly advantageous to manage this complication in a hybrid OR or by a mobile C-arm to get a clear intraoperative angiogram.

Management of Noncatastrophic Internal Carotid Artery Injury in Endoscopic Skull Base Surgery

Arterial injuries are the most feared complication of endoscopic skull base surgery. During resection of the middle fossa component of a large ventral skull base chondrosarcoma, arterial bleeding was encountered near the right internal carotid artery (ICA). Durable hemostasis could not be achieved with packing and the patient was taken for an emergent angiogram that revealed a pseudoaneurysm of the proximal intradural ICA. Given the presence of good collateral flow through the anterior and posterior communicating arteries, the right ICA was sacrificed by coil embolization. The patient was taken back to the operating room for closure then transferred to the intensive care unit and maintained on vasopressors for five days to ensure adequate perfusion. The right ICA was coil embolized and the patient was taken back to the operating room for closure. The patient recovered without complication. Arterial injuries, although serious, are not always catastrophic. Critical steps are immediate recognition of bleeding, vascular imaging, and vessel sacrifice if necessary.

Beyond the Learning Curve: Comparison of Microscopic and Endoscopic Incidences of Internal Carotid Injury in a Series of Highly Experienced Operators

BACKGROUND

As the endoscopic endonasal approach (EEA) has gained popularity as an alternative to microsurgery (MS) for transsphenoidal resection (TSR), numerous studies have attempted to assess the differential risk of internal carotid artery (ICA) injury between the techniques, yet results have been equivocal and contradictory. The aim of this study was to evaluate ICA injury in MS versus EEA among highly experienced neurosurgeons.

METHODS

We performed a systematic literature review of publications from 2002-2017 reporting ICA injury outcomes in ≥250 cases using MS or EEA.

RESULTS

Seventeen series reporting 11,149 patients were included: 3 MS series, 13 EEA series, and 1 series with adequate samples for each. ICA injury incidences were 0.0%-1.6% in cohorts of 275-3000. MS series documented 5 ICA injuries in 2672 operations, for an overall incidence of 0.2% (range, 0.0%-0.4%), and EEA series reported 30 ICA injuries in 8477 operations, for a 0.4% injury rate (range, 0.0%-1.6%); the difference was nonsignificant (P = 0.25). Increased operative experience was associated with decreased incidence of ICA injury, a finding preserved in the overall study cohort and within discretely examined MS and EEA subgroups (overall r² = 0.08, MS r² = 0.23, EEA r² = 0.07).

CONCLUSIONS

ICA injury is the most serious complication of TSR of pituitary neoplasms. Operator inexperience may be a more important risk factor than choice of surgical technique, given the comparably low rates of injury obtained by highly experienced surgeons independent of technique. This emphasizes the need for consolidated care in pituitary centers of excellence, improvement of high-fidelity simulators, and skull base mentorship between senior and junior staff.

[Complications after endoscopic endonasal transsphenoidal removal of pituitary adenomas]

The use of endoscopic technique has significantly extended the indications for surgery using the transsphenoidal approach. Currently, more than 90% of pituitary adenomas are operated on transsphenoidally. Transnasal removal of giant pituitary adenomas has become possible. Transition to the endoscopic endonasal approach in removal of pituitary adenomas changed the rate and structure of postoperative complications. We analyzed potential complications after endoscopic endonasal transsphenoidal removal of pituitary adenomas. These include complications of the approach itself (nasal bleeding, perforation of the nasal septum, impaired olfactory function, atrophic rhinitis, synechiae, mucoperiosteal flap necrosis, and external nasal deformities), infectious complications (meningitis, intracranial abscesses), cerebral circulation disorder (subarachnoid hemorrhage, cerebral vasospasm, injury to large vessels, intracranial hematomas), neuro-ophthalmological complications (visual and oculomotor disorders), endocrine (hypopituitarism, diabetes insipidus, hyponatremia) and somatic complications, and nasal liquorrhea. In conclusion, it should be noted that despite continuous improvement of the technique for endoscopic endonasal removal of pituitary adenomas, there is a risk of serious complications, which necessitates the development of techniques for prevention of these complications.

Landmarks to Identify Petrous Apex Through Endonasal Approach Without Transgression of Sinus

Objectives  The use of nasopharyngeal landmarks to localize the petrous apex has not been previously described. We describe a purely endoscopic endonasal corridor to localize the petrous apex without transgressing any of the paranasal sinuses. Methods  Anatomical dissections of four formalin preserved cadaveric heads (eight petrous apices) were performed to evaluate the feasibility of a nonsinus-based approach and illustrate the surgical landmarks and measurements that are useful for surgery in this area. Results  The Eustachian tubes, fossa of Rosenmüller (FR), and posterior end of the middle and inferior turbinates are constant landmarks, which can be identified without opening any nasal sinuses. The petrous apex is located on an extended straight line connecting the upper end of the torus tubarius (TT) and the roof of the FR. The distance from upper end of TT to the roof of FR measured 9.875 (±0.99) mm, and the distance from roof of the FR to the petrous apex measured 9.75 (±1) mm. Conclusion  With well-defined landmarks, the inferior, medial petrous apex can be reached using the endoscopic endonasal approach without crossing the sinus cavities.