Controlling the surgical field during a large endoscopic vascular injury

Pilot Validation of a 3-Dimensional Printed Pituitary Adenoma, Vascular Injury, and Cerebrospinal Fluid Leak Surgical Simulator

BACKGROUND AND OBJECTIVES

Endoscopic skull base surgery is a subspecialty field which would benefit significantly from high-fidelity surgical simulators. Giving trainees the opportunity to flatten their learning curve by practicing a variety of procedures on surgical simulators will inevitably improve patient outcomes.

METHODS

Four neurosurgeons, 8 otolarynologists, and 6 expert course faculty agreed to participate. All participants were asked to perform a transsphenoidal exposure and resection of a pituitary adenoma, repair a cerebrospinal fluid (CSF) leak, control a carotid injury, and repair a skull base defect. The content, face, and construct validity of the 3-dimensional printed model was examined.

RESULTS

The heart rate of the participants significantly increased from baseline when starting the carotid injury simulation (mean 90 vs 121, P = .029) and significantly decreased once the injury was controlled (mean 121 vs 110, P = .033, respectively). The participants reported a significant improvement in anxiety in facing a major vascular injury, as well as an increase in their confidence in management of major vascular injury, resecting a pituitary adenoma and repair of a CSF leak using a 5-point Likert scale (mean 4.42 vs 3.58 P = .05, 2 vs 3.25 P < .001, 2.36 vs 4.27 P < .001 and 2.45 vs 4.0 P = .001, respectively). The mean Objective Structured Assessment of Technical Skills score for experienced stations was 4.4, significantly higher than the Objective Structured Assessment of Technical Skills score for inexperienced stations (mean 3.65, P = .016).

CONCLUSION

We have demonstrated for the first time a validated 3-dimensional printed surgical simulator for endoscopic pituitary surgery that allows surgeons to practice a transsphenoidal approach, surgical resection of a pituitary adenoma, repair of a CSF leak in the diaphragma sellae, control of a carotid injury, and repair of skull base defect.

Is there a relationship between sphenoid sinus pneumatization and carotid canal-intersinus septa connection?

OBJECTIVES

We investigated the relationship between sphenoid sinus (SS) pneumatization types, carotid canal types and carotid canal-intersinus septa connection.

METHODS

The paranasal sinus computed tomography (PNSCT) images of 274 patients (141 males and 133 females) were evaluated retrospectively. SS pneumatization, SS intersinus septation, SS intersinus septa deviation, carotid canal classification, carotid canal dehiscence, carotid canal-intersinus septa connection and presence of Onodi cells were evaluated.

RESULTS

In presellar and sellar SS, type 1 carotid canal was detected. However, type 3 carotid canal was detected more in postsellar SS. On the left side, in 26.4% of the postsellar SS, carotid canal dehiscence was detected. On the right side, carotid canal-intersinus septa connection was detected in 55.8% of the postsellar SS and 35.1% of the sellar SS. On the left side, it was detected 58.3% of the postsellar SS and 30.9% of the sellar SS. In postsellar type SS pneumatized cases, right caroid canal-intersinus septa connection increased by 5.4 fold and left carotid canal-intersinus septa connection increased by 7.3 fold compared to presellar type SS pneumatization. In 2≥ intersinus septa group, left carotid canal-intersinus septa connection increased 5.0 fold compared to 'no septa' group.

CONCLUSION

In this study, we evaluated SS pneumatization types and their relation with carotid canal types and carotid canal-intersinus septa connections. Type 3 carotid canal (protrudation to SS wall) was detected more in postsellar SS. In these cases, surgeons should be very careful during surgery to avoid damage to the internal carotid artery (ICA).

Internal Carotid Injury during Skull Base Surgery-Case Report and a Review of the Literature

Iatrogenic injury of the internal carotid artery (ICA) is a rare, and probably underreported, complication of transnasal endoscopic skull base surgery. Although treatment algorithms have been suggested, there is no definite consensus or guideline for the management of this severe complication. We describe a case of ICA injury that occurred during a transsphenoidal biopsy of a tumor in the cavernous sinus and we present a treatment algorithm for managing this complication. We reviewed the articles published from 1998 to 2021, reporting on major vascular injury during transnasal endoscopic skull base surgery and endonasal endoscopic surgery, and we compare the methods and results of ICA injury management reported in the literature with the presented case. The most promising treatment for ICA injury might be packing with a muscle graft initially, then performing an endovascular intervention.

Carotid artery injury in endoscopic endonasal surgery: Risk factors, prevention, and management

Objective

Endoscopic approaches for sinus and skull base surgery are increasing in popularity. The objective of this narrative review is to characterize risk factors for internal carotid artery injury in endoscopic endonasal surgery (EES), highlight preventative measures, and illustrate key management principles.

Data Sources

Comprehensive literature review.

Methods

Relevant literature was reviewed using PubMed/MEDLINE.

Results

Carotid artery injury in EES is rare, with most studies reporting an incidence below 0.1%. Anatomic aberrancies, wide dissection margins, as well as specific provider and hospital factors, may increase the risk of injury. Multidisciplinary teams, comprehensive preoperative imaging, patient risk assessment, and formal training in vascular emergencies may reduce the risk. Management protocols should emphasize proper visualization of the injury site, fluid replacement, rapid packing, angiography, and endovascular techniques to achieve hemostasis.

Conclusions

While EES is a relatively safe procedure, carotid artery injury is a devastating complication that warrants full consideration in surgical planning. Important preventative measures include identifying patients with notable risk factors and obtaining preoperative imaging. Multidisciplinary teams and management protocols are ultimately necessary to reduce morbidity and mortality.

Internal carotid artery (ICA) injury is a rare complication of endoscopic endonasal surgery.

Risk factors for ICA injury may include vascular anatomic variants, invasive pathology, and prior radiation therapy.

Surgical team preparation and experience are key to successful management of operative complications.

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.

The potential of chitosan-based haemostats for use in neurosurgical setting - Literature review

Haemorrhage is a major nuance in neurosurgery since blood can distort the surgeon's field of view and increase the risk of post-operative complications. Currently a variety of commercially available haemostats have been approved for use in neurosurgery, but they have caveats to their use in the brain, including, localised tissue compression, neural toxicity, induce immune reaction or form thrombus within the vessel. Thus, there is a need for haemostats that are efficacious and safe for application on brain and spinal tissue. Chitosan is a naturally occurring bio-polymer that is found on the exoskeleton of arthropods and the cell wall of fungi. Chitosan has been shown to accelerate haemostasis through a myriad of physiological pathways. These findings have led to the development of multiple chitosan-based haemostats, for use in peripheral human tissue. Although, clinical data regarding the use of chitosan-based haemostats in the brain is lacking, a range on in vivo studies have proven chitosan to be efficacious and safe in managing neurosurgical bleeds. Similarly, literature comparing chitosan-based haemostats with commercial haemostats used commonly in neurosurgery, have all demonstrated chitosan to be the superior agent. Additionally, clinical trials of chitosan-based haemostat used in peripheral tissue have all demonstrated chitosan to be safe for human use. The marriage of these findings indicates that the safety and superior efficacy of chitosan-based haemostat, makes it a potentially suitable haemostat for use in neurosurgical setting. However, further research pertaining to the clinical use of chitosan-based haemostat within the central nervous system needs to be conducted.

Inadvertent internal carotid artery (ICA) injury during transsphenoidal surgery: review of literature

Background

Internal carotid artery (ICA) injury is a hazardous catastrophe for the skull base surgery team. We aimed to illustrate the vital joints in this hazardous event during endoscopic surgery.

Main text

The condition is rare (1.1%) but fatal per se. Working in the field of endoscopic surgery is not free of charges. It demands a thorough knowledge of anatomy, variations, and pathoanatomy to expect what can be seen thereafter. Once the injury occurs, one must have a quite clear plan to proceed. Marvelous bleeding is confusing not only in the field but also in the mind process.

Conclusion

Endoscope teams when expose to this event should think in a stepwise manner. In our review, we explained the pathoanatomy of the field after an injury, pre-conditions of injury, and how to avoid certain drawbacks during management.

A novel technique to manage internal carotid artery injury in endoscopic endonasal skull base surgery in the premise of proximal and distal controls

Intraoperative internal carotid artery injury is one of the most daunting complications in endoscopic skull base surgery. This paper proposed a novel technique to manage ICA injury after proximal and distal controls. The appropriate block sites together with the proximal and distal controls of ICA were demonstrated in six injected cadaveric specimens. The surgical outcomes of five patients with intraoperative ICA injury and managed with this concept were retrospectively reviewed. Five block sites for vascular control could be identified in all six specimens, including (1) distal to the distal dural ring, (2) proximal to the proximal dural ring, (3) anterior genu of the parasellar ICA, (4) the upper third of the paraclival ICA, and (5) just above the foramen lacerum. Both proximal and distal controls of ICA were achieved by using the block sites in combination. Gross tumor resection was achieved in all five cases after the intraoperative ICA injury was successfully managed. Three coping techniques were used, including direct coagulation to seal (three cases), endoscopic suture (one case), and coagulation to sacrifice (one case). Focal brainstem infarction occurred in one case, one patient died of intracranial infection, and the other three cases had no sequelae. No pseudoaneurysm occurred in all patients. Except the sacrificed ICA, the other ICA was intact during follow-up. It is technically feasible to manage ICA injuries after proximal and distal controls during EEA surgeries. The surgical outcomes from our case series supported the use of this novel technique.

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.

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.

Rhinology: Simulation Training (Part 2)

Purpose of Review

Recently, there has been an expansion of novel technologies in simulation training. The aim of this review was to examine existing evidence about training simulators in rhinology, their incorporation into real training programmes and translation of these skills into the operating room. The first part focuses on the virtual and augmented reality simulators. The second part describes the role of physical (i.e. non-computer-based) models of endoscopic sinus surgery.

Recent Findings

We learned that an ideal sinus surgery model would score highly in all standard measures of validity whilst maintaining an attainable cost. This is a challenging goal that is worthy of pursuit given that simulation training has been shown to be cost-effective option in other domains. Non-AR or VR models are attractive ways to fill gaps in simulation training whilst reducing compared with computer-based models.

Summary

In an era of improved computer technology and improved 3D printing, it will be increasingly important to focus on both the manufacture and validation process. One area that will benefit from further technological advancement is the realistic simulation of bleeding as this would obviate the need for animal models. Future studies on ESS simulation will also need to robustly demonstrate the validity of each model with the emphasis on the ability of a model to predict performance in operative environment.

Extended Endoscopic Endonasal Clipping of Intracranial Aneurysms: An Anatomic Feasibility Study

BACKGROUND

Intracranial aneurysms (IAs) located in the midline region represent formidable challenge owing to their deep location. The objective of this study was to assess feasibility and identify the limitations of endoscopic endonasal clipping of IAs. We further aimed to describe the locations and characteristics of aneurysms that may be amenable for endoscopic endonasal clipping; thus outlining the indications of these approaches.

METHODS

Fifteen latex-injected cadaveric heads were used for endoscopic endonasal exposure of anterior and posterior cerebral circulations. An aneurysm simulator model with 2 different sizes was used at the common sites for IAs to emulate a real surgery. Key measured parameters included "exposure of vessels and their respective perforators," "ability to gain proximal/distal control," and "possibility of clip placement" according to the size, direction, and location of the aneurysm model. Maneuverability of instruments and the need for pituitary gland transposition were assessed and recorded as well.

RESULTS

Exposure of the anterior communicating artery complex and the common sites of posterior circulation aneurysms were feasible. The size, location, and direction of the aneurysm model had an impact on obtaining proximal and/or distal control, and the ability of clip placement.

CONCLUSIONS

Clipping of midline aneurysms of the posterior circulation is feasible via endoscopic endonasal approach. Small-sized ventrally and medially directed aneurysm models carried a better probability of getting proximal and/or distal control, as well as better overall ability to place a clip. The endonasal route seems to provide a limited condition for proper management of anterior circulation aneurysms.

"Live Cadaver" Model for Internal Carotid Artery Injury Simulation in Endoscopic Endonasal Skull Base Surgery

BACKGROUND

Intraoperative injury of the internal carotid artery (ICA) is the most dreaded complication in endoscopic endonasal surgery (EES) of skull base. Training for ICA injury is practically impossible in live operative settings.

OBJECTIVE

To evaluate a pulsatile perfusion-based live cadaveric model for ICA injury simulation in a laboratory setting. The major emphasis of the study was to evaluate various means of controlling acute bleeding and evaluating the practical utility of this model for training purposes.

METHODS

Five embalmed, uninjected cadaveric heads were prepared for study by connecting to a pulsatile perfusion pump system filled with artificial blood solution. EES approaches were used to evaluate different types of ICA injuries similar to operative scenarios. Various methods of managing ICA injuries such as packing, clipping, and trapping, were evaluated. The educational advantages of the live cadaver model were assessed using questionnaires given to participants in a hands-on dissection course.

RESULTS

The trainee was faced with several scenarios similar to those encountered during an actual intraoperative ICA injury. Packing, clipping, and trapping of the ICA injury were successfully achieved in all segments of the ICA. Clip-based reconstruction techniques were successfully developed. All trainees reported gaining new knowledge, learning new techniques. The responses to the questionnaire confirmed the significant educational value of this model.

CONCLUSION

The live cadaver model presented here provides real-life experience with major vessel injury during EES in a laboratory setting. This model could significantly improve current training for the management of intraoperative vascular injuries during EES.

Internal carotid artery injury during endonasal sinus surgery: our experience and review of the literature

Iatrogenic internal carotid artery injury is a catastrophic but uncommon complication of endonasal sinus surgery. We present our experience in managing this emergency situation. A 52-year-old man underwent revision endoscopic repair of recurrent cerebrospinal fluid leak that was complicated with profuse haemorrhage during removal of the anterior wall of sphenoid sinus using a Hajek sphenoid punch forceps. Immediate packing of the sphenoid sinus controlled the haemorrhage. Urgent angiography revealed injury at the paraclival segment of the left internal carotid artery. An endovascular stent was initially placed but thrombosed; it was subsequently converted to coil embolisation. The patient had watershed cerebral infarct with hemiparesis post procedure but made full recovery within 6 weeks. Immediate nasal packing followed by urgent angiography and endovascular stent placement is the least invasive definitive treatment. If stenting is unsuccessful, endovascular balloon occlusion or coil embolisation is the next preferred treatment, if there is adequate cross-cerebral circulation. The success of treatment relies on its immediate management by a multidisciplinary team.

Endoscopic Endonasal Repair of Internal Carotid Artery Injury during Endoscopic Endonasal Surgery

Background  Injury to the cavernous portion of the internal carotid artery (ICA) during endoscopic skull base surgery is a well-recognized rare complication that can be associated with high rates of morbidity and mortality. Many techniques have been suggested to manage ICA injury with varying degrees of success.

Objectives  We provide a detailed technical description of an operative technique for endoscopic management of carotid artery injury.

Methods  A case of ICA injury during endoscopic skull base surgery is presented. The immediate treatment measurements include: (1) early recognition of ICA injury, (2) briefing of the team and preparations, (3) packing, (4) harvesting of temporalis muscle patch, (5) placement of the muscle patch over the defect, and (6) gentle compression for 10 minutes.

Results  The technique facilitates quick repair and restores normal blood flow through the damaged artery. Exsanguination or the symptoms of stroke that may occur from prolonged occlusion of the ICA are therefore prevented.

Conclusion  The proposed protocol is useful for the management of a potentially life-threatening ICA injury.

Simulating Internal Carotid Artery Injury during Transsphenoidal Transclival Endoscopic Surgery in a Perfused Cadaver Model

Introduction  Managing internal carotid artery (ICA) injury during extended endoscopic transsphenoidal surgery is an extreme challenge. We aimed to find a possible surgical treatment strategy. Methods  We operated seven fresh, perfused cadaver heads with a transsphenoidal endoscopic approach of the ICA using a three-dimensional-high definition (3D-HD) endoscope. We made a paraclival ICA leak, which we tried to manage with clips and microsutures. Results  Accurate transsphenoidal clip application on the ICA was impossible with standard aneurysm clips and applier. It was only feasible with a 9 mm slightly bended clip that could be opened from the inside and be applied with a dedicated flexible thin applier. Transsphenoidal suturing of an ICA leak was impossible from the ipsilateral nostril or with standard microinstruments. Suturing was only feasible from the contralateral nostril using flexible microinstruments with a thin 90-mm shaft. This was technically very challenging and involved a steep learning curve. Conclusion  Tamponade with muscle or fat and a quick transfer to the angiography suite for endovascular control remains the preferable option in case of an ICA leak during endoscopic transsphenoidal surgery. If tamponade gives insufficient initial control, ICA clipping could be possible with dedicated instruments, with risk of increasing the defect, stenosis, or occlusion of the vessel. Transsphenoidal ICA suturing remains extremely difficult, and laboratory practice seems essential.

Platelet activation by crushed and uncrushed muscle: a flow cytometry analysis

BACKGROUND

Crushed autologous muscle is used in skull base surgery in the acute phase of major arterial hemorrhage to stop bleeding. The mechanism of this is not yet clear, but is thought to involve the formation of a platelet plug, which seals the vessel wall defect but still allows ongoing blood flow to the brain.

METHODS

In this study we use flow cytometry to replicate the in-vivo actions of crushed muscle on platelets in whole blood. We compare the ratio of activation of platelets exposed to crushed and uncrushed muscle supernatant in control patients and in patients on antiplatelet agents.

RESULTS

Crushed muscle activated platelets to a higher degree than uncrushed muscle: 5.18-fold greater in control blood (p = 0.002); 6.53-fold greater in aspirin-exposed blood (p < 0.0001); and 9.4-fold greater in clopidogrel-exposed blood (p < 0.0001).

CONCLUSION

Crushed muscle caused a consistently increased ratio of platelet activation when compared with uncrushed muscle across all groups, adding to the evidence that at least part of its clinical effect is the result of platelet activation.

Nano-hemostats and a Pilot Study of Their Use in a Large Animal Model of Major Vessel Hemorrhage in Endoscopic Skull Base Surgery

Nano-hemostats are synthetic amino acid chains that self-assemble into a scaffold under certain conditions. These have been shown to be effective in stopping bleeding in small animal models of hemorrhage. Proposed mechanisms for their effect are that they form a mesh analogous to the fibrin plug in native hemostasis and that they may potentiate both platelet activation and the coagulation cascade. These may potentially become valuable adjuncts to endoscopic skull base surgery where there is the potential for both major vessel injury and smaller perforator injury to eloquent areas where bipolar cautery may not be suitable. We present a summary of the clinical studies to date and a small pilot study of nano-hemostat in an endoscopic sheep model of major vessel hemorrhage to determine its efficacy in stopping bleeding in this potentially catastrophic complication.

Simulation Training for Vascular Emergencies in Endoscopic Sinus and Skull Base Surgery

Carotid artery injury during endonasal surgery is a feared and potentially catastrophic complication. Simulation training provides the opportunity for a realistic experience with management of major vascular injuries. The sheep model of carotid artery injury reproduces the challenges of dealing with vascular emergencies during endoscopic sinus and skull base surgery, which include working in narrow nasal confines, high-flow/high-pressure vascular injury, and the immediately challenging surgical field. Simulated vascular emergencies allow for research and development; training using various surgical techniques to control the field, including hemostatic products or direct vascular closure techniques; and consequently improved patient care and outcomes.

Management of arterial injury during endoscopic sinus and skull base surgery

PURPOSE OF REVIEW

The most feared complication during endonasal surgery is a carotid artery injury. The sheep model of carotid injury provides training for this event by giving a realistic endoscopic experience of major vascular injuries and tissue hemostasis.

RECENT FINDINGS

The sheep model of carotid artery injury recreates the narrow nasal confines and high-flow/high-pressure vascular injury accurately reproducing the endoscopic challenges seen in such vascular emergencies. This has led to the development of surgical techniques that quickly and effectively control the field of bleeding and achieve reliable hemostasis including the crushed muscle patch new direct vascular closure technologies. Vascular emergency simulation training is achieving better outcomes for our patients.

SUMMARY

All skull base surgeons are at risk of the unexpected carotid artery injury and recently, the sheep model not only effectively recreates this situation but has identified clinically tried and tested techniques at managing this situation and is improving patient outcomes.

Intrasphenoid septations inserted into the internal carotid arteries: a frequent and risky relationship in transsphenoidal surgeries

Introduction

When an expanded endonasal transsphenoidal surgical approach is performed, intrasphenoid septations must be completely resected. If these structures are close to the internal carotid artery (ICA), then their manipulation might cause vascular injury.

Objective

The objective of this study is to describe the frequency of intrasphenoid septations in the internal carotid artery protuberance (ICAp).

Methods

Computed tomography (CT) scans of 421 patients were analysed. Intrasphenoid septations (classified as intersphenoid or accessory) and their relationship to the ICAp were described. Additionally, a sphenoid sinus classification was performed based on their degree of pneumatisation to determine whether a difference exists in the frequency of intrasphenoid septations inserted into ICAp with regard to sinus type.

Results

The patient mean age was 39 ± 21.4 years. Overall, 219 patients (52%) had septations in the ICAp; 359 patients (85.3%) had intersphenoid septations; of the latter, 135 (37.6%) had septations in the ICAp. This frequency was higher among patients with sphenoid sinus type 4 or 5 (44.7% and 43.5%, respectively). Accessory septations were found in 255 patients (60.6%); 140 of these septations (54.9%) were in the ICAp. Among 351 patients with types 3, 4 or 5 sphenoid sinuses (i.e., only well-pneumatised sphenoid sinuses), 219 (62.4%) had septations in the ICAp. These frequencies are higher than those reported in most previous studies.

Conclusion

The frequency of intrasphenoid septations in the ICAp found is considerable. It is higher among patients with more pneumatised sinuses. This finding justifies an appropriate pre-operative study, and careful attention must be paid during transsphenoidal surgery.

Endoscopic endonasal control of the paraclival internal carotid artery by Fogarty balloon catheter inflation: an anatomical study

OBJECTIVE Neurosurgical management of many vascular and neoplastic lesions necessitates control of the internal carotid artery (ICA). The aim of this study was to investigate the feasibility of achieving control of the ICA through the endoscopic endonasal approach by temporary occlusion with a Fogarty balloon catheter. METHODS Ten endoscopic endonasal paraseptal approaches were performed on cadaveric specimens. A Fogarty balloon catheter was inserted through a sellar bony opening and pushed laterally and posteriorly extraarterially along the paraclival carotid artery. The balloon was then inflated, thus achieving temporary occlusion of the vessel. The position of the catheter was confirmed with CT scans, and occlusion of the ICA was demonstrated with angiography. The technique was performed in 2 surgical cases of pituitary macroadenoma with cavernous sinus invasion. RESULTS Positioning the Fogarty balloon catheter at the level of the paraclival ICA was achieved in all cadaveric dissections and surgical cases through a minimally invasive, quick, and safe approach. Inflation of the Fogarty balloon caused interruption of blood flow in 100% of cases. CONCLUSIONS Temporary occlusion of the paraclival ICA performed through the endoscopic endonasal route with the aid of a Fogarty balloon catheter may be another maneuver for dealing with intraoperative ICA control. Further clinical studies are required to prove the efficacy of this method.

The Expanded Endoscopic Endonasal Approach to Anterior Communicating Artery Aneurysms: A Cadaveric Morphometric Study

OBJECTIVE

The purpose of this study was to explore the endoscopic endonasal approach to the anterior communicating artery complex.

DESIGN

Anatomic, morphometric analysis of human cadaver heads.

SUBJECTS

Fifteen latex-injected adult cadaver heads.

MAIN OUTCOME MEASURES

The anatomic boundaries of the operative field and the dimensions of exposure of the anterior communicating artery (ACoA) complex were measured and clip placement feasibility was assessed.

RESULTS

Exposure of the ACoA and bilateral A1 and A2 segments was accomplished in all 15 cadaver heads. Average length of the exposed ACoA was 3 ± 1 mm, the left A1 was 5 ± 3 mm and right A1 was 5 ± 1 mm, while the A2 segment was 5 ± 2 mm bilaterally. The average distance from the alar floor to the ACoA was 95 mm, while proximal lateral limit measured between the alar floor margins was 36 mm. The distal lateral limit as defined by the distance between the lateral most exposed margins of the chiasm was 19 mm. Clip placement was accomplished for the ACoA and the A1 and A2 segments bilaterally in all specimens.

CONCLUSION

The endoscopic, endonasal transtuberculum, transplanum approach is an anatomically feasible alternative to treating select aneurysms of the ACoA complex.

Endoscopic endonasal surgery for sinonasal and skull base lesions in the pediatric population

Endoscopic endonasal skull base surgical techniques, initially developed in adult patients, are being utilized with increasing frequency in pediatric patients to treat sinonasal and skull base lesions. This article reviews the current state of endoscopic endonasal approaches to the skull base to both treat disease and reconstruct the skull base in pediatric patients. Sinonasal and skull base embryology and anatomy are reviewed as a foundation for understanding the disease processes and surgical techniques. Selected skull base pathologies and conditions that involve the pediatric skull base are also reviewed.

Endoscopic Endonasal Clipping of Intracranial Aneurysms: Surgical Technique and Results

OBJECTIVE

Microsurgical clipping of intracranial aneurysms requires meticulous technique and is usually performed through open approaches. Endoscopic endonasal clipping of intracranial aneurysms may use the same techniques through an alternative corridor. The aim of this article is to report a series of patients who underwent an endoscopic endonasal approach (EEA) for microsurgical clipping of intracranial aneurysms.

METHODS

We conducted a retrospective chart review. Surgical outcome and complications were noted. The conceptual application and the technical nuances of these procedures are discussed.

RESULTS

Ten patients underwent EEA for clipping of 11 intracranial aneurysms arising from the paraclinoidal internal carotid artery (n = 9) and vertebrobasilar system (n = 2). The internal carotid artery aneurysms projected medially, whereas the vertebrobasilar artery aneurysms were directly ventral to the brainstem with low-lying basilar apices. One patient required craniotomy for distal control given the size and thrombosed nature of the aneurysm. Proximal and distal vascular control with direct visualization of the aneurysm was obtained in all patients. In all cases, aneurysms were completely occluded. Among complications, 3 patients had postoperative cerebrospinal fluid leakage and 2 other patients had meningitis. Two patients suffered lacunar strokes. One recovered completely and the other remains with mild disabling symptoms.

CONCLUSIONS

EEAs can provide direct access for microsurgical clipping of rare and carefully selected intracranial aneurysms. The basic principles of cerebrovascular surgery have to be followed throughout the procedure. These surgeries require a skull base team with a neurosurgeon well versed in both endoscopic endonasal and cerebrovascular surgery, working in concert with an otolaryngologist experienced in skull base endoscopy and reconstruction.

Management of carotid artery injury in endonasal surgery

Introduction Carotid artery injury (CAI) is the most feared and potentially catastrophic intraoperative complication an endoscopic skull base surgeon may face. With the advancement of transnasal endoscopic surgery and the willingness to tackle more diverse pathology, evidence-based management of this life-threatening complication is paramount for patient safety and surgeon confidence.

Objectives We review the current English literature surrounding the management of CAI during endoscopic transnasal surgery.

Data Synthesis The searched databases included PubMed, MEDLINE, Cochrane database, LILACS, and BIREME. Keywords included “sinus surgery,” “carotid injury,” “endoscopic skull base surgery,” “hemostasis,” “transsphenoidal” and “pseudoaneurysm.”

Conclusions Review of the literature found the incidence of CAI in endonasal skull base surgery to be as high as 9% in some surgeries. Furthermore, current treatment recommendations can result in damage to critical neurovascular structures. Management decisions must be made in the preoperative, operative, and postoperative setting to ensure adequate treatment of CAI and the prevention of its complications such as pseudoaneurysm. Emphasis should be placed on surgical competency, teamwork, and technical expertise through education and training.

Computed Tomographic Exploration of the Middle Ethmoidal Artery

Objectives The integral involvement of sinus and skull base surgeries in the field of otolaryngology makes the endonasal vasculature including the ethmoidal arteries important to consider. The anterior ethmoidal artery (AEA) and posterior ethmoidal artery (PEA) are well-known entities, yet the relatively recent notion of accessory or middle ethmoidal vessels complicates our understanding of this arterial system. Study Design Radiographic study. Methods Fifty computed tomographic angiographies were studied for the presence of accessory/middle ethmoidal arteries (MEAs). If contrasted arteries were not visualized reliably, foramina were accepted as evidence of arteries. The accessory arteries/foramina were then compared with the locations of the AEA and PEA. Results A total of 19 of the 50 patient samples studied had evidence of a right, left, or bilateral middle ethmoidal vessels (38%). Overall, 26 arteries total were identified out of the 100 sides (26%). Unilateral middle arteries were more common than bilateral, and right sided were more common than left. There was no evidence of multiple MEAs on a given side. Conclusion The endonasal surgeon must be cognizant of the possible presence of MEAs. These arteries should be considered when working in the medial orbit and anterior skull base region.

Hemostasis in Endoscopic Endonasal Skull Base Surgery

William Halsted established the basic principles of modern surgical technique highlighting the importance of meticulous hemostasis and careful tissue handling. These concepts hold true today and are even more critical for endoscopic visualization, making hemostasis one of the most relevant cornerstones for the safe practice of endoscopic endonasal surgery (EES) of the skull base. During preoperative assessment, patients at higher risk for serious hemorrhagic complications must be recognized. From an anatomical point of view, EES can be grossly divided in two major components: sinonasal surgery and sellar-cranial base surgery. This division affects the choice of appropriate technique for control of bleeding that relies mainly on the source of hemorrhage, the tissue involved, and the proximity of critical neurovascular structures. Pistol-grip or single-shaft instruments constitute the most important and appropriately designed instruments available for EES. Electrocoagulation and a variety of hemostatic materials are also important tools and should be applied wisely. This article describes the experience of our team in the management of hemorrhagic events during EES with an emphasis on technical nuances.

Advantages and limitations of endoscopic endonasal approaches to the skull base

BACKGROUND

The anatomy of the skull base is extremely complex with an abundance of critical neurovascular bundles and their corresponding foramina as well as the insertions and origins of multiple masticatory and craniocervical muscles. These anatomic intricacies increase the difficulty of surgery within this area.

METHODS

Advantages and disadvantages of endoscopic endonasal approaches (EEAs) based on the authors' sequential learning and experience are described.

RESULTS

EEAs offer the advantages of using preexistent air spaces that enable accessing various areas of the skull base, while avoiding external incisions or scars and obviating the need for the translocation of the maxillofacial skeleton. In addition, EEAs are well suited to preserve neurologic, visual, and masticatory functions as well as cosmesis. However, the sinonasal corridor must be expanded and optimized to access the skull base adequately, facilitate the reconstruction of the surgical defect, avoid sinonasal complications, and minimize sequelae. Important considerations can limit or indicate the approach, such as the nature of the pathology, including location, diagnosis, and vascularity; patient characteristics, including age and medical comorbidities; surgeon attributes, including training, experience, and expertise; the resultant need to reconstruct large skull base defects and feasible alternatives to do so; and institutional resources, including adjunctive services, an intensive care unit, and operating room equipment.

CONCLUSIONS

EEAs are important techniques in contemporary skull base surgery. Understanding the indications for and limitations of these approaches help to maximize outcomes.

Carotid artery injury during endoscopic endonasal skull base surgery: incidence and outcomes

BACKGROUND

Injury to the internal carotid artery (ICA) during endoscopic endonasal skull base surgery is a feared complication that is not well studied or reported.

OBJECTIVE

To evaluate the incidence, to identify potential risk factors, and to present management strategies and outcomes of ICA injury during endonasal skull base surgery at our institution.

METHODS

We performed a retrospective review of all endoscopic endonasal operations performed at our institution between 1998 and 2011 to examine potential factors predisposing to ICA injury. We also documented the perioperative management and outcomes after injury.

RESULTS

There were 7 ICA injuries encountered in 2015 endonasal skull base surgeries, giving an incidence of 0.3%. Most injuries (5 of 7) involved the left ICA, and the most common diagnosis was chondroid neoplasm (chordoma, chondrosarcoma; 3 of 7 [2% of 142 cases]). Two injuries occurred during 660 pituitary adenoma resections (0.3%). The paraclival ICA segment was the most commonly injured site (5 of 7), and transclival and transpterygoid approaches had a higher incidence of injury, although neither factor reached statistical significance. Four of 7 injured ICAs were sacrificed either intraoperatively or postoperatively. No patient suffered a stroke or neurological deficit. There were no intraoperative mortalities; 1 patient died postoperatively of cardiac ischemia. One of the 3 preserved ICAs developed a pseudoaneurysm over a mean follow-up period of 5 months that was treated endovascularly.

CONCLUSION

ICA injury during endonasal skull base surgery is an infrequent and manageable complication. Preservation of the vessel remains difficult. Chondroid tumors represent a higher risk and should be resected by surgical teams with significant experience.

A Perfusion-based Human Cadaveric Model for Management of Carotid Artery Injury during Endoscopic Endonasal Skull Base Surgery

Objective To create and develop a reproducible and realistic training environment to prepare residents and trainees for arterial catastrophes during endoscopic endonasal surgery. Design An artificial blood substitute was perfused at systolic blood pressures in eight fresh human cadavers to mimic intraoperative scenarios. Setting The USC Keck School of Medicine Fresh Tissue Dissection Laboratory was used as the training site. Participants Trainees were USC neurosurgery residents and junior faculty. Main Outcome A 5-point questionnaire was used to assess pre- and posttraining confidence scores. Results High-pressure extravasation at normal arterial blood pressure mimicked real intraoperative internal carotid artery (ICA) injury. Residents developed psychomotor skills required to achieve hemostasis using suction, cottonoids, and muscle grafts. Questionnaire responses from all trainees reported a realistic experience enhanced by the addition of the perfusion model. Conclusions The addition of an arterial perfusion system to fresh tissue cadavers is among the most realistic training models available. This enables the simulation of rare intraoperative scenarios such as ICA injury. Strategies for rapid hemostasis and implementation of techniques including endoscope manipulation, suction, and packing can all be rehearsed via this novel paradigm.

Early and late complications of endoscopic hemostatic techniques following different carotid artery injury characteristics

BACKGROUND

The most dreaded hemorrhagic complication in endoscopic endonasal surgery is injury to the internal carotid artery (ICA). Although a number of treatment protocols are currently used, none have been formally investigated. This study aims to compare the efficacy of the muscle patch, bipolar diathermy, and aneurysm clip on hemostasis, pseudoaneurysm formation, and long-term vessel patency for different injury types in a sheep model of carotid bleeding.

METHODS

Twenty-seven sheep underwent ICA dissection/isolation followed by the artery placement within a modified "sinus model otorhino neuro trainer" (SIMONT) model. Standardized linear, punch, and stellate injuries were made. Randomization of sheep to receive 1 of 3 hemostatic techniques was performed (muscle, bipolar, clip). Specific outcome measures included attainment of primary hemostasis, time to hemostasis, blood loss, pseudoaneurysm formation, and carotid patency on follow-up magnetic resonance imaging (MRI).

RESULTS

Bipolar achieved primary hemostasis in 7 of 9 cases and 2 cases of secondary hemorrhage. It had no associated pseudoaneurysm formation. Carotid patency was variable on follow-up MRI. Muscle patch achieved 100% primary hemostasis with 2 cases of secondary hemorrhage. There were 2 cases of pseudoaneurysm and 100% patency rate on follow-up MRI. Aneurysm clip achieved 100% primary hemostasis with 1 case of secondary hemorrhage. No pseudoaneurysm formation and a 50% rate of carotid insufficiency on MRI.

CONCLUSION

This study shows that the crushed muscle patch and aneurysm clip can be viable options in the management of ICA injury with short-term and long-term benefits. Complications associated with these techniques were comparable if not reduced when compared to the published literature.

Endoscopic resection of sinonasal cancers

Sinonasal malignancies, a rare group of tumors, are characterized by histological heterogeneity and poor survival. As improvements in image-guidance and endoscopic technologies became incorporated into head and neck oncologic and neurosurgical practice, the application of these technologies and techniques to the surgical management of sinonasal malignancy began. Over the past decade, there has been increasing evidence regarding the safety and oncological effectiveness of these techniques. Several institutions have reported their experience with endoscopic surgery and have shown reduced morbidity, better quality of life, and survival outcomes equivalent to those of open surgery in carefully selected patients. Endoscopic cranial base surgery is a rapidly evolving field. We review the literature on oncological outcomes, safety, quality of life, and recent technological advances.

Delayed carotid pseudoaneurysm: a life-threatening complication after endoscopic sinus surgery

Internal carotid artery pseudoaneurysm is a rare but potentially lethal complication of sinus surgery. We present 2 cases of delayed carotid pseudoaneurysm development after internal carotid laceration during functional sinus surgery for chronic sinusitis to emphasize the need to follow up the patients with profuse bleeding perioperatively and to identify when to suspect iatrogenic vascular malformations.

Endoscopic endonasal technique: treatment of paranasal and anterior skull base malignancies

Objective

Method

Conclusion

Endoscopic endonasal transplanum approach to the paraclinoid internal carotid artery

Objective To investigate the relevance of an endoscopic transnasal approach to the surgical treatment of paraophthalmic aneurysms. Setting Binasal endoscopic transplanum surgery was performed. Participants Seven cadaver heads were studied. Main Outcome Measures (1) Dimensions of the endonasal corridor, including the operative field depth, lateral limits, and the transplanum craniotomy. (2) The degree of vascular exposure. (3) Surgical maneuverability and access for clip placements. Results The mean operative depth was 90 ± 4 mm. The lateral corridors were limited proximally by the alar rim openings (29 ± 4 mm) and distally by the distance between the opticocarotid recesses (19 ± 2 mm). The mean posteroanterior distance and width of the transplanum craniotomy were 19 ± 2 mm and 17 ± 3 mm, respectively. Vascular exposure was achieved in 100% of cases for the clinoidal internal carotid artery (ICA), ophthalmic artery, superior hypophyseal artery, and the proximal ophthalmic ICA. Surgical access and clip placement was achieved in 97.6% of cases for vessels located anterior to the pituitary stalk (odds ratio [OR] 73.8; 95% confidence interval [CI] 7.66 to 710.8; p = 0.00). Conclusion The endoscopic transnasal approach provides excellent visualization of the paraclinoid region vasculature and offers potential surgical alternative for paraclinoid aneurysms.

Endoscopic endonasal approach for the treatment of a large clival giant cell tumor complicated by an intraoperative internal carotid artery rupture

Giant cell tumors (GCTs) are primary bone neoplasms that rarely involve the skull base. These lesions are usually locally aggressive and require complete removal, including the surrounding apparently healthy bone, to provide the best chance of cure. GCTs, as well as other lesions located in the clivus, can nowadays be treated by a minimally invasive fully endoscopic extended endonasal approach. This approach ensures a more direct route to the craniovertebral junction than other possible approaches (transfacial, extended lateral, and posterolateral approaches). The case reported is a clival GCT operated on by an extended endonasal approach that provides another contribution on how to address one of the most feared complications attributed to this approach: a massive bleed due to an internal carotid artery injury.

A cadaveric study of the endoscopic endonasal transclival approach to the basilar artery

The anterior transclival route to basilar artery aneurysms is not widely performed. The objective of this study was to carry out a feasibility assessment of the transclival approach to basilar aneurysms with advanced endonasal techniques on 11 cadaver heads. Clival dura was exposed from the sella to the foramen magnum between the paraclival segments of the internal carotid arteries (ICA) laterally. An inverted dural "U" flap was reflected inferiorly to expose the basilar artery. The maximal dimensions from operative measurements were recorded. Surgical manoeuvrability of multiple instruments and the proficiency to place proximal and distal vascular clips were evaluated. The mean operative depth (± standard deviation), measured from the anterior choanae to the basilar artery, was 110±6mm. The lateral corridors were limited distally by the medial pterygoids (mean width 21±2mm) and paraclival ICA (mean width 20±2mm). The mean transclival craniectomy dimensions were 19±2mm (width) and 23±4mm (height). Exposure of the basilar-anterior inferior cerebellar artery junction, superior cerebellar artery, and the basilar caput were possible in 100%, 91%, and 64% of instances, respectively. Placements of proximal and distal aneurysm clips were achieved in all instances. Based on our findings, the transclival endoscopic endonasal surgery approach provides excellent visualisation of the basilar artery. Clip application and manoeuvrability of instruments was considered adequate for basilar aneurysm surgery. Surgical skills and instrumentation to control significant haemorrhage can potentially limit the clinical applicability of this technique.

Endoscopic surgery of skull base chordomas

Objective To assess our clinical experience in treating midline intracranial pathology using minimally invasive surgical techniques. Design Retrospective chart review of patients undergoing endoscopic endonasal resection of clival chordomas. Setting Two tertiary referral centers in Australia and New Zealand. Main Outcome Measures Patients were assessed by intraoperative findings (macroscopic resection rate, tumor size, and operative complications) and clinical outcomes (residual disease, postoperative complications, recurrence rate, and mortality). Results Fourteen patients underwent endoscopic resection of clival chordomas (seven primary, seven revision) with a mean follow-up of 41.45 months (3 to 104 months). Macroscopic resection rates were 71% and 29%, respectively. Mean operative time was 386 minutes. Overall cerebrospinal fluid (CSF) leak rate was 3/14 (21%) and, using the nasoseptal flap, it was 0/5 (0%). Two patients developed late recurrence; one died of disease and one was treated with intensity modulated radiation therapy. Overall mortality was 2/14 (14%). Conclusion Endoscopic resection of clival chordomas is a safe and viable alternative to the traditional open approach. The nasoseptal flap is an excellent method of obtaining a watertight skull base closure. Furthermore, this series highlighted the fact that the primary attempt at surgery offers the best chance to achieve a total resection.

Indications and limitations of endoscopic skull base surgery

A wealth of critical neurovascular structures within a relatively small surface area adds to the already intricate nature of skull base surgery. Surgical approaches to the area are difficult and often associated with significant morbidity and mortality. During the past two decades, endoscopic endonasal approaches (EEAs) have evolved to access the ventral skull base for the resection of tumors (benign and malignant), the decompression of neural structures including the cervicomedullary junction (pannus from rheumatoid arthritis or congenital anomalies, such as platybasia) and the reconstruction of skull base defects (cerebrospinal leaks, meningoencephalocele). These minimal access approaches obviate the need for external incisions, translocation of maxillofacial bones and retraction of the brain. Furthermore, EEAs yield improved visualization, which may reduce complications, and improve quality of life outcomes. Anatomical difficulties (e.g., vascular encasement or extension beyond the plane of a major vessel or cranial nerve), various special conditions (e.g., pediatric patients and vascular tumor) and limitation of institutional resources and technical difficulties may limit the use of EEAs. Thus, one should understand the indications and limitations of EEAs to optimize patient selection, which, in turn, may lead to superior surgical outcomes and reduced morbidity.