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

The 'muscle wonton' repair - A case series of internal carotid artery injuries at a single Centre during its 10-year experience in endoscopic transsphenoidal pituitary surgery

INTRODUCTION

Although rare, injury to the internal carotid artery (ICA) during pituitary surgery may result in serious morbidity such as stroke or death. This case series explores a single centre's incidence and outcomes of ICA injury during endoscopic transsphenoidal pituitary surgery, discusses the current management options, and introduces the 'muscle wonton' (morcellised muscle wrapped in a single sheet of Surgicel®) as being a viable repair option.

METHODS

All patients undergoing pituitary operations from January 2010 to December 2019 at the Queen Elizabeth Hospital, Birmingham, UK were included. Primary outcome was number of internal carotid artery injuries during pituitary surgery. Secondary outcome measures included pre-operative (demographic, risk factors such as previous radiotherapy, number of previous operations, imaging available), operative (intra-operative image guidance, intra-operative doppler ultrasound, which side ICA was damaged, repair technique) and post-operative result (death, cranial nerve VI palsy, or stroke).

RESULTS

7 out of 893 patients (0.8%) were identified as having an ICA injury. Four of the injuries were left sided. Average age was 54 years old, five were male. In four of the ICA injuries intra-operative navigation imaging was used, and a further two concurrently used ultrasound doppler. Three of the seven cases resulted in permanent morbidity (stroke). There were no other consistent demographic, pre-operative, operative, or post-operative similarities. The two patients with muscle wonton repair suffered no permanent serious complication of ICA injury (i.e. death, abducens nerve palsy, stroke).

DISCUSSION

Our findings resemble the current literature, with left sided ICA injury being more common. Different methods for repairing ICA injury exist, however morcellised muscle patches have shown significant promise in animal models, and the perforated Surgicel® helps create an easy delivery method. The muscle wonton is a viable surgical option for repairing ICA injuries during pituitary surgery.

Anatomical localization of horizontal segment of the petrous internal carotid artery in transnasal endoscopic skull base surgery

OBJECTIVE

To discuss the localization of horizontal segment of petrous internal carotid artery in transnasal endoscopic skull base surgery, and to provide anatomical data for clinical surgery.

METHODS

The horizontal segment of the petrous internal carotid artery of 5 adult cadaveric heads were exposed by endoscopic transnasal and microscopic open approaches respectively, and the relevant data and images were measured and collected.

RESULTS

The medial wall of the foramen spinosum is the lateral wall of the isthmus of the eustachian tube, and the thickness of the bone is 0.5 ± 0.2 mm. The medial wall of the isthmus of the eustachian tube is the lateral wall of the posterior genu of the carotid canal and the thickness of the bone is 0.2 ± 0.1 mm. The vidian nerve originates from the anterior genu of the petrous internal carotid artery. The distance from the base of vidian nerve to the isthmus of eustachian tube is 19.2 ± 2.8 mm.

CONCLUSION

The foramen spinosum is the landmark of isthmus of the Eustachian tube. The isthmus of the Eustachian tube is the landmark of the posterior genu of the internal carotid artery. The line between the base of the vidian nerve and the isthmus of the Eustachian tube ioks the landmark of horizontal segment of the petrous internal carotid artery.

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).

Endoscopic Approaches to the Paramedian Skull Base: An Anatomic Comparison of Contralateral Endonasal and Transmaxillary Strategies

BACKGROUND

The expanded endoscopic endonasal approach (EEA) is limited laterally by the internal carotid artery (ICA). The EEA to the paramedian skull base often requires complex maneuvers such as dissection of the Eustachian tube (ET) and foramen lacerum (FL), and ICA manipulation. An endoscopic contralateral transmaxillary approach (CTMA) has the potential to provide adequate exposure of the paramedian skull base while bypassing manipulation of the aforementioned anatomic structures.

OBJECTIVE

To quantify and compare the surgical nuances of a CTMA and a contralateral EEA when approaching the paramedian skull base in cadaveric specimens.

METHODS

Five adult cadaveric heads were dissected bilaterally (10 sides) using a contralateral EEA and a CTMA to expose targets of interest at the paramedian skull base. For each target in both approaches, the surgical freedom, angle of attack, the corridor's "perspective angle," and "turning angle" to circumvent the ICA, ET, and FL were obtained.

RESULTS

The CTMA achieved superior surgical freedom at all targets ( P < .05) except at the root entry point of cranial nerve XII. The CTMA provided superior vertical and horizontal angles of " attack " to the majority of targets of interest. Except when approaching the root entry point of cranial nerve XII, the CTMA " turning angle " around the ICA, ET, and FL were wider with CTMA for all targets.

CONCLUSION

A CTMA complements the EEA to access the paramedian skull base. A CTMA may limit the need for complex maneuvers such as ICA mobilization and dissection of the ET and FL when approaching the paramedian skull base.

Clinical effect of high-flow revascularization in microsurgery combined with endoscopic endonasal surgery for skull base tumors with intracranial and extracranial involvement

Background

The objective of the study is to investigate the surgical methods and clinical effects of high-flow revascularization in microsurgery combined with endoscopic endonasal surgery for skull base tumors with intracranial and extracranial involvement.

Methods

The relationships between skull base tumors and internal carotid artery (ICA), tumor location and size, and the extent of tumor invasion were assessed. Preoperative CT perfusion (CTP), magnetic resonance (MR) perfusion-weighted imaging (PWI) (MR-PWI), and digital subtraction angiography (DSA) were performed to evaluate collateral circulation and brain tissue perfusion. Then craniotomy through the fronto-orbitozygomatic approach was performed, based on which four cases received extended middle skull base approach+Dolenc approach + Fukushima bypass type I, and six cases received extended middle skull base approach+Fukushima bypass type III. After surgery, DSA, CT angiogram (CTA), and CTP/PWI were performed to evaluate the patency of the reconstructed vessels and cerebral perfusion, and contrast-enhanced MRI to evaluate the degree of tumor resection. All patients were followed up for 6-12 months.

Results

Among the 10 cases investigated, gross total resection was achieved in 8 cases, subtotal resection in 1 case, and partial resection in 1 case, as confirmed by CT and enhanced MRI. The patency of revascularization vessels was observed using fluorescein angiography during the operation in all patients and via DSA and CTA postoperatively in nine patients. One patient underwent ventilator-assisted ventilation because of respiratory failure and failed to undergo DSA and CTA. Regarding postoperative complications, one patient developed watershed cerebral infarction on the operated side but no sequelae after drug treatment, three patients developed facial numbness, which improved after 3 months, and two patients experienced worsened diplopia. After 6 to 12 months of follow-up on the nine evaluable patients, the Glasgow Outcome Scale (GOS) was 4-5 after surgery. In addition, 6-month follow-up results showed that one patient with clival chondrosarcoma developed recurrence on contrast-enhanced MRI, while no relapse was observed in the other patients.

Conclusion

For skull base tumors with intracranial and extracranial invasion and involving the ICA, revascularization might improve the total resection rate and reduce the recurrence rate and risk of intraoperative bleeding and postoperative ischemia.

Emergency treatment and anesthesia management of internal carotid artery injury during neurosurgery: Four case reports

BACKGROUND

During skull base surgery, intraoperative internal carotid artery (ICA) injury is a catastrophic complication that can lead to fatal blood loss or secondary cerebral ischemia. Appropriate management of ICA injury plays a crucial role in the prognosis of patients. Neurosurgeons have reported multiple techniques and management strategies; however, the literature on managing this complication from the anesthesiologist’s perspective is limited, especially in the aspect of circulation management and airway management when patients need transit for further endovascular treatment.

CASE SUMMARY

We describe 4 cases of ICA injury during neurosurgery; there were 3 cases of pathologically proven pituitary adenoma and 1 case of cavernous sinus endothelial meningioma. After the onset of ICA injury, all four patients were immediately transferred for endovascular therapy under general anesthesia with vital signs monitored and mechanical ventilation. Three patients were transferred to the hybrid operating room, and one patient was transferred to the catheter operating room. Three patients underwent covered stent implantation, and one patient underwent embolization. All four patients experienced hypovolemic shock and received blood products infusion and vasoactive drugs to maintain stable circulation. After the neurosurgery, one patient was extubated and returned to the ward, and the other three were delayed tracheal extubation and returned to the intensive care unit. One patient died from serious neurological complications after 62 d in the hospital, but the other three showed good clinical outcomes.

CONCLUSION

ICA injury imposes a high risk of massive hemorrhage and subsequent infarction. Immediate treatment is critical and requires interdisciplinary collaboration among neurosurgeons, anesthesiologists, and interventional neuroradiologists. Effective hemostatic methods, stable hemodynamics sufficient to ensure perfusion of vital organs, airway safety during transit, rapid localization and implementation of appropriate measures to occlude the damaged vessel are strong guarantees of patient safety.

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.

Complications of Endoscopic Skull Base Surgery for Sellar and Parasellar Tumors in Pediatric Population; Neurosurgical Perspectives

Background

Advances in surgical techniques based on in-depth anatomical knowledge of the skull base have broadened the indications for endoscopic skull base surgery (ESS) with the advantage of wide and direct surgical exposure while minimizing invasiveness. However, the low incidence of the indicated diseases and narrow surgical corridors in children have limited the popularization of ESS. In addition, surgical complications and preventive interventions are not yet well known. Therefore, we retrospectively investigated the complications and prevention methods of ESS in children with a comprehensive review.

Methods

We retrospectively analyzed the medical records of pediatric patients who underwent ESS for sellar and parasellar tumors at Seoul National University Children's Hospital from July 2010 to December 2020. Visual and endocrine status, extent of resection, complications, and recurrences were investigated depending on the pathology of the tumor. In addition, a comprehensive literature review regarding the complications of pediatric ESS was performed.

Results

A total of 98 patients were enrolled. The median age of the patients was 12 years, and 52 patients were male. Preoperative visual disturbance was found in 53 patients, anterior pituitary function deficit in 69, and diabetes insipidus in 32. Gross total resection was attempted in 67 patients and achieved in 62 (93%). Biopsy and cyst fenestration were the goals of surgery in 26 patients, and all were achieved as planned. Regarding outcomes, visual disturbance worsened in two patients (2%), endocrine status was aggravated in 34 (35%) patients, and new-onset diabetes insipidus occurred in 27 (41%) patients. The overall surgical complication rate (other than aggravation of visual or endocrine status) was 17%. Postoperative meningitis (12%) was the most common complication, followed by cerebrospinal fluid leakage (2%), vasospasm, hemorrhage and infarction. By pathological diagnosis, craniopharyngioma had the highest complication rate of 29%. All but one patient with postoperative hemorrhage showed no permanent deficits.

Conclusion

ESS in children is feasible and relatively safe. More attention and different postoperative management protocols are required in children to avoid complications, especially in craniopharyngiomas. However, the complications can be mostly managed conservatively without permanent neurologic deficits.

Injury to the Extrasellar Portion of the Internal Carotid Artery during Endoscopic Transsphenoidal Surgery: A Case Report

Background

Injury to the internal carotid artery (ICA) during endoscopic transsphenoidal surgery (ETSS) is a serious complication with a risk of mortality. ICA injury during ETSS usually occurs during intrasellar manipulations and rarely occurs in the extrasellar portion. Several hemostatic procedures have been proposed for ICA injury in the intrasellar portion, whereas hemostatic methods for ICA injury in the extrasellar portion, where the ICA is surrounded by bone structures, are less well known.

Case Presentation

A 65-year-old man with an incidental pituitary tumor underwent ETSS. The petrous portion of the left ICA was injured during resection of the sphenoid septum connected with left carotid prominence using a cutting forceps. Bleeding was too heavy for simple hemostatic techniques. Hemostasis using a crushed muscle patch was tried unsuccessfully during controlling of the bleeding. Eventually, the injured site of the ICA was covered with cotton patties followed by closing with a vascularized pedicled nasoseptal flap. Cerebral angiography immediately after surgery showed no extravasation from the injured site of the left ICA petrous portion. However, a carotid-cavernous sinus fistula originating from the injured ICA site was detected 7 days after surgery, so the vascular reconstructive surgery combined with left ICA occlusion was performed. The overall postoperative course was uneventful.

Conclusion

We believe that emergency application of the cottonoids may be effective for hemostasis against ICA injury in the extrasellar portion during ETSS, but further vascular reconstruction combined with ICA occlusion on the injured side and removal of the cottonoids would be required.

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.

Endoscopic Orientation of Juxta-Pituitary Carotid in Transsphenoidal Approaches: Critical Considerations for Clinical Applications

Accidental injury of the internal carotid artery (ICA) remains one of the most challenging complications reported in the endoscopic endonasal transsphenoidal approaches (EETA) particularly, in sphenoid sinuses with ill-defined carotid bony landmarks. The purpose of this study was to describe an anatomical model for the endoscopic orientation of juxta-pituitary segment of ICA in relation to the lateral optico-carotid recess (OCR) as a nearby bony landmark. Cadaveric dissection was conducted progressively in twenty fresh adult cadavers simulating the EETA. After reducing posterior and lateral walls of sphenoid sinuses, various measurements were taken from both lateral OCRs to "contact points" of the juxta-pituitary segment of ICA and lateral margins of the pituitary gland. Current results have enabled us to divide the region between lateral OCRs into three compartments. Two lateral parasellar compartments contain juxta-pituitary segments of ICA showing a mean width of 8 mm; with a narrow range of 7-10 mm; and a central inter-carotid sellar compartment represents the safe region for bone drilling showing widely variable widths ranging between 9 to 20 mm. In all specimens; variation in the width of the inter-carotid compartment correlated with the distance between both lateral OCRs. This study improves surgeons' awareness of the ICA course variations in the EETA through sphenoid sinuses with ill-defined bony landmarks. An appreciation of the measurements gathered from this study can help in operative training, and can also provide a base for future studies to confirm ICA courses associated with higher risk of injury.

Petrous bone lesions: surgical implementation and outcomes of extradural subtemporal approach

BACKGROUND

Petrous bone lesions (PBLs) are rare with few reports in the neurosurgical literature. In this study, the authors describe our current technique of extradural subtemporal approach (ESTA). The objective of this study was to evaluate the role and efficacy of ESTA for treatment of the PBLs. To our knowledge, this is the largest reported clinical series of using an ESTA-treated PBLs in which the clinical outcomes were evaluated.

METHODS

Between 1994 and 2019, 67 patients with PBLs treated by ESTA were retrospectively reviewed. Extent of resection, neurological outcomes, recurrence rate, and surgical complications were evaluated and compared with previous studies. The indications, advantages, limitations, and outcomes of ESTA were analyzed according to pathology.

RESULTS

This series included 7 facial nerve schwannomas (10.4%), 16 cholesterol granulomas (23.9%), 16 chordomas (23.9%), 6 chondrosarcomas (9%), 5 trigeminal schwannomas (7.5%), 9 epidermoids/dermoids (13.4%), and 8 other pathologies (11.9%). The most common location of PBLs operated with ESTA was at the petrous apex and rhomboid areas (68.7%). Gross total resection was achieved in 35 (55.6%). Symptomatic improvement occurred in 56 patients (83.6%). Complications occurred in 7 (10.4%) of cases including one mortality. Nine patients (17%) had recurrence within the mean follow-up 71 months. Compared to previous literature, our results demonstrated comparable outcomes but with higher rates of hearing and facial nerve preservation as well as minimal morbidity. From our results, ESTA is an effective therapeutic option for lesions located at the rhomboid and petrous apex, particularly when patients presented with intact facial and hearing function.

CONCLUSION

Our series demonstrated that ESTA provided satisfactory outcomes with excellent benefits of hearing and facial function preservation for patients with petrous bone lesions. ESTA should be considered as a safe and effective therapeutic option for selected patients with PBLs.

Characterization of outcomes and practices utilized in the management of internal carotid artery injury not requiring definitive endovascular management

BACKGROUND

After internal carotid artery (ICA) injury during endoscopic skull base surgery, the majority of patients undergo ICA embolization or stenting to treat active extravasation or pseudoaneurysm development. However, management practices when embolization or stenting is not required have not been well described. The objective of this study was to determine how patients with ICA injury but no embolization, stenting, or ligation do long-term and ascertain the reconstruction methods utilized.

METHODS

Twenty-nine cases of ICA injury were identified in an international multi-institutional retrospective review. Of these, we identified six cases that were not treated with embolization, stenting, or ICA sacrifice. Information was available for five cases.

RESULTS

A muscle patch was used in the immediate repair of each case. A nasoseptal flap was used in one case. Prefabricated nasal tampons were used in all cases. Nasal packing was initially left in for a median of 7 days prior to removal. The initial muscle patch was reinforced with a second muscle graft in one case. One case demonstrated ICA bleeding at the time of packing removal and was repacked an additional week. Follow-up for each of these cases was at least 2 years. No cases of subsequent carotid rupture were found and none of these cases ultimately underwent endovascular stenting. Radiation or proton therapy has not been subsequently used in any of these patients.

CONCLUSIONS

This study details the reconstruction, lessons learned, and long-term follow-up for five cases of ICA injury not treated with embolization, stenting, or ligation.

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.

Internal Carotid Artery Injury in Transsphenoidal Surgery: Tenets for Its Avoidance and Refit-A Clinical Study

One of the most serious/potentially fatal complications of transsphenoidal surgery (TSS) is internal carotid artery (ICA) injury. Of 6230 patients who underwent TSS, ICA injury occurred in 8 (0.12%). The etiology, possible treatment options, and avoidance of ICA injury were analyzed. ICA injury occurred at two different stages: (1) during the exposure of the sella floor and dural incision over the sella and cavernous sinus and (2) during the resection of the cavernous sinus extension of the tumor. The angiographic collateral blood supply was categorized as good, sufficient, and nonsufficient to help with the decision making for repairing the injury. ICA occlusion with a balloon was performed at the injury site in two cases, microcoils in two patients, microcoils plus a single barrel extra-intracranial high-flow bypass in one case, stent grafting in one case, and no intervention in two cases. The risk of ICA injury diminishes with better preoperative preparation, intraoperative navigation, and ultrasound dopplerography. Reconstructive surgery for closing the defect and restoring the blood flow to the artery should be assessed depending on the site of the injury and the anatomical features of the ICA.

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.

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.

Rupture from cavernous internal carotid artery pseudoaneurysm 11 years after transsphenoidal surgery

Carotid artery pseudoaneurysm is a rare complication of transsphenoidal surgery, usually diagnosed within 90 days post procedure. Sequelae of pseudoaneurysm rupture, such as severe epistaxis or carotid cavernous fistula (CCF), have significant morbidity and mortality. A case of epistaxis from pseudoaneurysm rupture over a decade after transsphenoidal surgery is presented, with staged treatment using coiling, endonasal mucosal flap repair and interval flow-diverting stent insertion. This case illustrates that pseudoaneurysm rupture occurs regardless of time course after transsphenoidal surgery, and treatment strategies using combined endovascular and endonasal techniques are reviewed.

Anatomical location of the abducens nerves (VI) in the ventral approach of clival tumors

The aim of this work was to determine reliable anatomical landmarks for locating and preserving the abducens nerves (6th cranial nerves) during trans-facial or trans-nasal endoscopic approaches of skull base tumors involving the clivus and the petrous apex. In order to describe this specific anatomy, we carefully dissected 10 cadaveric heads under optic magnification. Several measurements were taken between the two petro-sphénoidal foramina, from the bottom of the sella and the dorsum sellae. The close relationship between the nerves and the internal carotid artery were taken into account. We defined a trapezoid area that allowed drilling the clivus safely, preserving the 6th cranial nerve while being attentive to the internal carotid artery. The caudal part of this trapezium is, on average, 20 mm long at mi-distance between the two petro-sphenoidal foramina. The cranial part is at the sella level, a line between both paraclival internal carotid arteries. Oblique lateral edges between the cranial and caudal parts completed the trapezium.

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.

Characterization of Anatomical Landmarks for Exposing the Internal Carotid Artery in the Infratemporal Fossa Through an Endoscopic Transmasticator Approach: A Morphometric Cadaveric Study

BACKGROUND

The Eustachian tube and sphenoid spine have been previously described as landmarks for endonasal surgical identification of the most distal segment of the parapharyngeal internal carotid artery (PhICA). However, the intervening space between the sphenoid spine and PhICA allows for error during exposure of the artery. In the present study, we have characterized endoscopic endonasal transmasticator exposure of the PhICA using the sphenoid spine, vaginal process of the tympanic bone, and the "tympanic crest" as useful anatomical landmarks.

METHODS

Endonasal dissection was performed in 13 embalmed latex-injected cadaveric specimens. Two open lateral dissections and osteologic analysis of 10 dry skulls were also performed.

RESULTS

A novel and palpable bony landmark, the inferomedial edge of the tympanic bone, referred to as the tympanic crest, was identified, leading from the sphenoid spine to the lateral carotid canal. Additionally, the vaginal process of the tympanic bone, viewed endoscopically, was a guide to the PhICA. The sphenoid spine was bifurcate in 20% of the skulls, with an average length of 5.98 mm (range, 3.9-8.2 mm), width of 5.81 mm (range, 3.0-10.6 mm), and distance to the carotid canal of 4.48 mm (range, 2.5-6.1 mm).

CONCLUSION

The sphenoid spine and pericarotid space has variable anatomy. Using an endoscopic transmasticator approach to the infratemporal fossa, we found that the closest landmarks leading to the PhICA were the tympanic crest, sphenoid spine, and vaginal process of the tympanic bone.

Carotid Artery Injury during Transsphenoidal Pituitary Surgery: Lessons from a 15-Year Modern Microsurgery Cohort

Background  Internal carotid artery (ICA) injury is a rare but potentially catastrophic complication of transsphenoidal resection (TSR) of pituitary tumors, potentially resulting in a host of deficits due to the risk of hemorrhage, ischemia, or even death. The endoscopic endonasal approach (EEA) has gained considerable popularity in the modern era, with few busy neurosurgeons remaining committed to practicing transnasal pituitary microsurgery. Our objective was therefore to characterize the overall incidence of ICA injury in a large, longitudinal, single-surgeon microscopic TSR series conducted during the modern EEA era. Methods  Retrospective case series. Results  Overall TSR volume by the senior author (F.B.M.) was 817 pituitary tumors during the study period, 2002 to 2017. Within that cohort, two instances of ICA injury were identified (0.2%), including one each with Cushing's disease and acromegaly, both of whom ultimately recovered without residual neurologic deficit. No pediatric injuries were identified. Conclusion  Vascular injury is an exceedingly rare complication of transsphenoidal pituitary surgery. Adjuncts to prevent this complication include careful review of the coronal magnetic resonance imaging, identification of the midline, as needed use of the Doppler, and initial caudal opening of the sellar dura. Although potentially disastrous, good neurologic outcomes may be obtained, with immediate judicious packing followed by immediate digital subtraction angiography to assess vessel patency and secondary complications such as pseudoaneurysm.

Assessment of the endoscopic endonasal approach to the basilar apex region for aneurysm clipping

OBJECTIVE

The expanded endoscopic endonasal approach (EEA) has shown promising results in treatment of midline skull base lesions. Several case reports exist on the utilization of the EEA for treatment of aneurysms. However, a comparison of this approach with the classic transcranial orbitozygomatic approach to the basilar apex (BAX) region is missing.The present study summarizes the results of a series of cadaveric surgical simulations for assessment of the EEA to the BAX region for aneurysm clipping and its comparison with the transcranial orbitozygomatic approach as one of the most common approaches used to treat BAX aneurysms.

METHODS

Fifteen cadaveric specimens underwent bilateral orbitozygomatic craniotomies as well as an EEA (first without a pituitary transposition [PT] and then with a PT) to expose the BAX. The following variables were measured, recorded, and compared between the orbitozygomatic approach and the EEA: 1) number of perforating arteries counted on bilateral posterior cerebral arteries (PCAs); 2) exposure and clipping lengths of the PCAs, superior cerebellar arteries (SCAs), and proximal basilar artery; and 3) surgical area of exposure in the BAX region.

RESULTS

Except for the proximal basilar artery exposure and clipping, the orbitozygomatic approach provided statistically significantly greater values for vascular exposure and control in the BAX region (i.e., exposure and clipping of ipsilateral and contralateral SCAs and PCAs). The EEA with PT was significantly better in exposing and clipping bilateral PCAs compared to EEA without a PT, but not in terms of other measured variables. The surgical area of exposure and PCA perforator counts were not significantly different between the 3 approaches. The EEA provided better exposure and control if the BAX was located ≥ 4 mm inferior to the dorsum sellae.

CONCLUSIONS

For BAX aneurysms located in the retrosellar area, PT is usually required to obtain improved exposure and control for the bilateral PCAs. However, the transcranial approach is generally superior to both endoscopic approaches for accessing the BAX region. Considering the superior exposure of the proximal basilar artery obtained with the EEA, it could be a viable option when surgical treatment is considered for a low-lying BAX or mid-basilar trunk aneurysms (≥ 4 mm inferior to dorsum sellae).

Radiological "Teddy Bear" Sign on CT Imaging to Aid Internal Carotid Artery Localization in Transsphenoidal Pituitary and Anterior Skull Base Surgery

Objectives  Internal carotid artery (ICA) injury remains a rare but potentially fatal complication of transsphenoidal pituitary or anterior skull base surgery. Preoperative imaging must be scrutinized to minimize risk. On axial computed tomography (CT), the protrusions of the ICAs into the sphenoid resemble a "teddy bear." This article aims to describe the sign, its grading system (0-2) and quantify its presence. Design  Retrospective review of preoperative CT imaging. Setting  Tertiary referral center in the United Kingdom. Participants  One hundred patients who underwent endoscopic transsphenoidal surgery for pituitary disease were enrolled. Main Outcome Measure  The presence and grading of the "teddy bear" sign were assessed on preoperative CT imaging. Results  A grade 2 (strongly positive) "teddy bear" sign was identified in 40% at the level of the superior pituitary fossa, 78% at the inferior pituitary fossa, and 59% at the clivus. A grade 1 (intermediate) sign was seen in 23.5, 7.5, and 10% of cases, respectively. In 5% of cases, the sign was grade 0 at all levels-indicating poor intraoperative localization of the ICA. Conclusion  The "teddy bear" sign is a useful preoperative tool for identification of anatomy predisposing patients to a higher risk of ICA injury. Those patients who have an absent or grade 0 "teddy bear" sign require extra care to ensure intraoperative localization of the ICAs which may include the use of neuronavigation or a Doppler probe. A grade 2 sign predicts good intraoperative localization of the ICA intraoperatively to inform the safe lateral limit of sellar bone resection.

Outcome of endoscopic vs microsurgical transsphenoidal resection for Cushing's disease

INTRODUCTION

It is unclear whether the proportions of remission and the recurrence rates differ between endoscopic transsphenoidal surgery (TS) and microscopic TS in Cushing's disease (CD); thus, we conducted a systematic review and meta-analysis to evaluate studies of endoscopic TS and microscopic TS.

METHODS

We conducted a comprehensive search of PubMed to identify relevant studies. Remission and recurrence were used as outcome measures following surgical treatment of CD.

RESULTS

A total of 24 cohort studies involving 1670 adult patients were included in the comparison. Among these studies, 702 patients across 9 studies underwent endoscopic TS, and 968 patients across 15 studies underwent microscopic TS. Similar baseline characteristics were observed in both groups. There was no significant difference in remission between the two groups: 79.7% (95% CI: 73.1-85.0%) in the endoscopic group and 76.9% (95% CI: 71.3-81.6%) in the microscopic group (P = 0.485). It appears that patients who underwent endoscopic surgery experience recurrence less often than patients who underwent microscopic surgery, with recurrence proportions of 11.0% and 15.9%, respectively (P = 0.134). However, if follow-up time is taken into account, both groups had a recurrence rate of approximately 4% per person per year (95% CI: 3.1-5.4% and 3.6-5.1%, P = 0.651).

CONCLUSIONS

We found that remission proportion and recurrence rate were the same in patients who underwent endoscopic TS as in patients who underwent microscopic TS. The definition of diagnosis, remission and recurrence should always be considered in the studies assessing therapeutic efficacy in CD.

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.

Injury of the Carotid Artery during Endoscopic Endonasal Surgery: Surveys of Skull Base Surgeons

Objectives  This study aimed to review endoscopic skull base surgeon experience with internal carotid artery (ICA) injuries during endoscopic endonasal surgery (EES) to provide an estimate of the incidence of ICA injury, the associated factors and identify the best training modalities for the management of this complication. Design  Anonymous electronic survey of past participants at a well-established endoscopic skull base surgery course and a global online community of skull base surgeons. Main Outcome Measures  Relative incidence of ICA injuries during EES, associated anatomic and intraoperative factors, and surgeon experience. Results  At least 20% of surgeons in each surveyed population experienced a carotid artery injury. Reported carotid artery injuries were most common during tumor exposure and removal (48%). The parasellar carotid artery was the most commonly injured segment (39%). Carotid artery injuries were more common in high-volume surgeons, but only statistically significant in one of the two populations. Attendance at a skull base course or courses did not change the incidence of carotid artery injury in either surveyed population. In both surveys, respondents preferred live surgeries or active (not computer simulated) training models. Conclusions  ICA injury is underreported and most common when manipulating the parasellar carotid artery for exposure and tumor dissection. Given the high morbidity and mortality associated with these injuries, vascular injury management should be prioritized and taught in a graduated approach by modern endoscopic skull base courses.

An Analysis of Anatomic Variations of the Sphenoid Sinus and Its Relationship to the Internal Carotid Artery

Introduction  The sphenoid sinus (SS) has a high variability; its anatomical relations and variations must be well understood prior to the expanded endoscopic surgery (EES) at the skull base via the endonasal transsphenoidal approach. A feared complication is injury to the internal carotid artery (ICA).

Objective  To evaluate the anatomic variations of the SS and its relationship to the ICA using computed tomography (CT).

Methods  Cross-sectional retrospective study. Analysis of 90 patients' CT scans on axial, coronal and sagittal planes with 1 mm slices, evaluating lateral and posterior extensions of pneumatization of the SS, deviation of the sphenoid septum, presence of septations and their relationship to the parasellar and paraclival segments of the internal carotid artery (psICA and pcICA, respectively).

Results  The association between the protrusions of the psICA and the pcICA was statistically significant ( p  < 0.001), as was the association between the lateral extension of pneumatization of the SS and the protrusion of the psICA ( p  = 0.014). The presence of the posterior extension of pneumatization of the SS and protrusion of the pcICA occurred in 46% of the cases. Deviation of the sphenoid septum in the direction of the pcICA was present in 14% and dehiscence of the pcICA was seen in 3.6% of the cases.

Conclusion  Using the CT scan to recognize the type of extensions of pneumatization of the SS, the deviation of the sphenoid septum, and the presence of septations is beneficial to identify accurately the ICA and to reduce the risk of injury to it.

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.

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.

Endoscopic Endonasal Approach for Suprasellar Lesions in Children: Complications and Prevention

The endoscopic endonasal approach (EEA) has been popularized in adults and has been applied to an expanding range of surgical modules and indications in this population. However, its clinical application in pediatric neurosurgery has been impeded by the differences in anatomical features and the relatively low incidence of diseases to which it is applicable. In this review article, we mainly discuss the surgical indications, feasibility, and complications of EEA for suprasellar lesions in children based on a review of the literature, focusing especially on the age-related anatomical features of the nasal cavity, various pathologic entities, and the impact of EEA on long-term craniofacial growth.

Anatomic Variations in Pituitary Endocrinopathies: Implications for the Surgical Corridor

Objectives/Hypotheses Functioning pituitary adenomas may produce endocrinopathies such as acromegaly and Cushing syndrome. Both conditions lead to characteristic anatomic variations as a result of hormonally induced abnormal soft tissue deposition. We evaluate the anatomic differences between acromegalics and Cushing disease patients and compare these dimensions to controls. Design Radiographic review of preoperative magnetic resonance images (MRI) of the pituitary gland. Setting Tertiary academic medical center. Participants Patients who underwent transnasal, transsphenoidal surgery for pituitary adenomas found to have acromegaly or pituitary Cushing between January 1, 2007 and September 1, 2015. A total of 15 patients with similar MRIs and no history of pituitary or sinonasal disease were selected as controls. Main Outcome Measures Dimensions assessed were intercarotid distance; carotid canal width; piriform aperture width; distance from the piriform aperture to the anterior face of the sphenoid; sphenoid sinus height, width, and length; angle from anterior nasal spine to anteroinferior face of sphenoid sinus; choanal height; and nasal cavity height at the level of the vertical segment of the middle turbinate. Sphenoid sinus pneumatization patterns were recorded. Results There were 30 acromegalics and 31 Cushing disease patients. When compared with controls, both acromegalics and Cushing disease patients had significantly wider piriform apertures and a longer distance from the piriform aperture to the anterior face of the sphenoid sinus (p < 0.05). Acromegalics had a significantly less acute angle (19 ± 3 degrees) from the anterior nasal spine to the sphenoid (p < 0.05). Cushing disease patients had significantly lower sphenoid sinus length and shorter nasal cavity height (p < 0.05). There were no differences in intercarotid distance or carotid canal width. Conclusions As acromegalics and Cushing disease patients have known anatomic variations, the skull base surgeon should be aware of these differences and adapt their techniques and approaches as needed.

First Application of 7-T Magnetic Resonance Imaging in Endoscopic Endonasal Surgery of Skull Base Tumors

BACKGROUND

Successful endoscopic endonasal surgery for the resection of skull base tumors is reliant on preoperative imaging to delineate pathology from the surrounding anatomy. The increased signal-to-noise ratio afforded by 7-T MRI can be used to increase spatial and contrast resolution, which may lend itself to improved imaging of the skull base. In this study, we apply a 7-T imaging protocol to patients with skull base tumors and compare the images with clinical standard of care.

METHODS

Images were acquired at 7 T on 11 patients with skull base lesions. Two neuroradiologists evaluated clinical 1.5-, 3-, and 7-T scans for detection of intracavernous cranial nerves and internal carotid artery (ICA) branches. Detection rates were compared. Images were used for surgical planning and uploaded to a neuronavigation platform and used to guide surgery.

RESULTS

Image analysis yielded improved detection rates of cranial nerves and ICA branches at 7 T. The 7-T images were successfully incorporated into preoperative planning and intraoperative neuronavigation.

CONCLUSIONS

Our study represents the first application of 7-T MRI to the full neurosurgical workflow for endoscopic endonasal surgery. We detected higher rates of cranial nerves and ICA branches at 7-T MRI compared with 3- and 1.5-T MRI, and found that integration of 7 T into surgical planning and guidance was feasible. These results suggest a potential for 7-T MRI to reduce surgical complications. Future studies comparing standardized 7-, 3-, and 1.5-T MRI protocols in a larger number of patients are warranted to determine the relative benefit of 7-T MRI for endonasal endoscopic surgical efficacy.

Quantitative analysis of anatomical relationship between cavernous segment internal carotid artery and pituitary macroadenoma

Cavernous segment internal carotid artery (CSICA) injury during endoscopic transsphenoidal surgery for pituitary tumor is rare but fatal. The aim of this study is to investigate anatomical relationship between pituitary macroadenoma and corresponding CSICA using quantitative means with a sense to improve safety of surgery.In this retrospective study, a total of 98 patients with nonfunctioning pituitary macroadenomas undergoing endoscopic transsphenoidal surgeries were enrolled from 2005 to 2014. Intercarotid distances between bilateral CSICAs were measured in the 4 coronal levels, namely optic strut, convexity of carotid prominence, median sella turcica, and dorsum sellae. Parasellar extension was graded and recorded by Knosp-Steiner classification.Our findings indicated a linear relationship between size of pituitary macroadenoma and intercarotid distance over CSICA. The correlation was absent in pituitary macroadenoma with Knosp-Steiner grade 4 parasellar extension.Bigger pituitary macroadenoma makes more lateral deviation of CSICA. While facing larger tumor, sufficient bony graft is indicated for increasing surgical field, working area and operative safety.

Complication Avoidance in Endoscopic Skull Base Surgery

Endoscopic endonasal approaches to the skull base pathology have developed and evolved dramatically over the past 2 decades, particularly with collaboration between neurosurgery and otolaryngology physicians. These advances have increased significantly the use of such approaches beyond just resection of pituitary adenomas, including a variety of skull base pathologies. As the field has evolved, so has our understanding of the complications accompanying endoscopic skull base surgery, as well as techniques to both avoid and manage these complications. These are discussed here.

Comparative analysis of the anterior transpetrosal approach with the endoscopic endonasal approach to the petroclival region

OBJECTIVE The endoscopic endonasal approach (EEA) offers direct access to midline skull base lesions, and the anterior transpetrosal approach (ATPA) stands out as a method for granting entry into the upper and middle clival areas. This study evaluated the feasibility of performing EEA for tumors located in the petroclival region in comparison with ATPA. METHODS On 8 embalmed cadaver heads, EEA to the petroclival region was performed utilizing a 4-mm endoscope with either 0° or 30° lenses, and an ATPA was performed under microscopic visualization. A comparison was executed based on measurements of 5 heads (10 sides). Case illustrations were utilized to demonstrate the advantages and disadvantages of EEA and ATPA when dealing with petroclival conditions. RESULTS Extradurally, EEA allows direct access to the medial petrous apex, which is limited by the petrous and paraclival internal carotid artery (ICA) segments laterally. The ATPA offers direct access to the petrous apex, which is blocked by the petrous ICA and abducens nerve inferiorly. Intradurally, the EEA allows a direct view of the areas medial to the cisternal segment of cranial nerve VI with limited lateral exposure. ATPA offers excellent access to the cistern between cranial nerves III and VIII. The quantitative analysis demonstrated that the EEA corridor could be expanded laterally with an angled drill up to 1.8 times wider than the bone window between both paraclival ICA segments. CONCLUSIONS The midline, horizontal line of the petrous ICA segment, paraclival ICA segment, and the abducens nerve are the main landmarks used to decide which approach to the petroclival region to select. The EEA is superior to the ATPA for accessing lesions medial or caudal to the abducens nerve, such as chordomas, chondrosarcomas, and midclival meningiomas. The ATPA is superior to lesions located posterior and/or lateral to the paraclival ICA segment and lesions with extension to the middle fossa and/or infratemporal fossa. The EEA and ATPA are complementary and can be used independently or in combination with each other in order to approach complex petroclival lesions.

Morphometric analysis of the medial opticocarotid recess and its anatomical relations relevant to the transsphenoidal endoscopic endonasal approaches

BACKGROUND

The medial opticocarotid recess (MOCR) is located in the posterior wall of the sphenoid sinus, medial to the junction of the optic canal (OC) and the carotid prominence (CP). There is controversy in the literature in relation to the presence of the MOCR and its constancy, which is relevant when approaching the skull base through an endoscopic route.

METHODS

The morphometric relations of the MOCR with the surrounding structures were studied in 18 cadaveric specimens after endoscopic endonasal approach (EEA).

RESULTS

The distance between both MOCR was 11.06 ± 1.14 mm; the distance between the MOCR and the lateral opticocarotid (LOCR) recess was 5.56 ± 0.85 mm; the distance between the MOCR and the suprasellar recess was 3.72 ± 0.49 mm; the angle between the MOCR plane and the OC 13.32 ± 2.30°; the angle between the MOCR plane and the CP 13.50 ± 2.68° and; the angle between the OC and the CP 26.81 ± 4.26°. All measurements showed low variability, with low standard deviation and interquartile range. No relations were found between any of the measurements.

CONCLUSIONS

The MOCR may be used as a reference point for precise location of structures during EEA. Objective measurements may be especially useful in cases with distorted sphenoid bone anatomy.

Extended transsphenoidal approach for pituitary adenomas invading the cavernous sinus using multiple complementary techniques

PURPOSE

Transsphenoidal surgery is the treatment of choice for most pituitary adenomas (PA), except prolactinomas. Difficulties achieving radical resection with this method are encountered in patients with PAs invading the cavernous sinus (CS), due to the inability of the standard transsphenoidal approach to expose all tumors adequately. This study analyzed methods to resect PAs invading the CS and factors influencing the degree of tumor resection and occurrence of complications.

METHODS

Outcomes were retrospectively analyzed in 52 patients with PA invading the CS who underwent surgery via the extended transsphenoidal approach utilizing multiple techniques, including microscopy, endoscopy, neuronavigation, and intraoperative Doppler ultrasonography.

RESULTS

Gross-total resection (GTR) was achieved in 33 patients (63.5 %). GTR rate was significantly higher in patients with Knosp Grade 3 than Knosp Grade 4 (92.3 vs. 53.8 %) and in patients undergoing initial surgery than reoperation (77.1 vs. 35.3 %). One patient (2.9 %) undergoing initial surgery experienced transient cranial nerve palsy, without other postoperative complications. Postoperative complications were significantly higher after reoperation. Firm tumor consistency was significantly more frequent in patients undergoing reoperation than initial surgery (52.9 vs. 8.6 %).

CONCLUSION

Extended transsphenoidal surgery incorporating multiple complementary techniques was highly effective for PAs invading the CS. Postoperative complications rates were relatively low, especially for patients undergoing initial surgery and those with Knosp Grade 3 tumors. Total resection of PAs invading the CS remains challenging, especially in patients undergoing reoperation or having firm tumors.

Intraoperative neurophysiological monitoring during endoscopic endonasal surgery for pediatric skull base tumors

OBJECT The aim of this study was to evaluate the value of intraoperative neurophysiological monitoring (IONM) using electromyography (EMG), brainstem auditory evoked potentials (BAEPs), and somatosensory evoked potentials (SSEPs) to predict and/or prevent postoperative neurological deficits in pediatric patients undergoing endoscopic endonasal surgery (EES) for skull base tumors. METHODS All consecutive pediatric patients with skull base tumors who underwent EES with at least 1 modality of IONM (BAEP, SSEP, and/or EMG) at our institution between 1999 and 2013 were retrospectively reviewed. Staged procedures and repeat procedures were identified and analyzed separately. To evaluate the diagnostic accuracy of significant free-run EMG activity, the prevalence of cranial nerve (CN) deficits and the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS A total of 129 patients underwent 159 procedures; 6 patients had a total of 9 CN deficits. The incidences of CN deficits based on the total number of nerves monitored in the groups with and without significant free-run EMG activity were 9% and 1.5%, respectively. The incidences of CN deficits in the groups with 1 staged and more than 1 staged EES were 1.5% and 29%, respectively. The sensitivity, specificity, and negative predictive values (with 95% confidence intervals) of significant EMG to detect CN deficits in repeat procedures were 0.55 (0.22-0.84), 0.86 (0.79-0.9), and 0.97 (0.92-0.99), respectively. Two patients had significant changes in their BAEPs that were reversible with an increase in mean arterial pressure. CONCLUSIONS IONM can be applied effectively and reliably during EES in children. EMG monitoring is specific for detecting CN deficits and can be an effective guide for dissecting these procedures. Triggered EMG should be elicited intraoperatively to check the integrity of the CNs during and after tumor resection. Given the anatomical complexity of pediatric EES and the unique challenges encountered, multimodal IONM can be a valuable adjunct to these procedures.

Endovascular management of internal carotid artery injuries secondary to endonasal surgery: case series and review of the literature

OBJECTIVE Internal carotid artery (ICA) injury is a rare but severe complication of endonasal surgery. The authors describe their endovascular experience managing ICA injuries after transsphenoidal surgery; they review and summarize the current literature regarding endovascular techniques; and they propose a treatment algorithm based on the available evidence. METHODS A retrospective review of 576 transsphenoidal pituitary adenoma resections was performed. Cases of ICA injury occurring at our institution and transfers from other hospitals were evaluated. Endovascular treatments for ICA injury reported in the literature were also reviewed and summarized. RESULTS Seven cases were identified from the institutional cohort (mean age 46.3 years, mean follow-up 43.4 months [1-107 months]) that received endovascular treatment for ICA injury. Five injuries occurred at our institution (5 [0.9%] of 576), and 2 injuries occurred at outside hospitals. Three patients underwent ICA sacrifice by coil placement, 2 underwent lesion embolization (coil or stent-assisted coil placement), and 2 underwent endoluminal reconstruction (both with flow diversion devices). Review of the literature identified 98 cases of ICA injury treated with endovascular methods. Of the 105 total cases, 46 patients underwent ICA sacrifice, 28 underwent lesion embolization, and 31 underwent endoluminal reconstruction. Sacrifice of the ICA proved a durable solution in all cases; however, the rate of persistent neurological complications was relatively high (10 [21.7%] of 46). Lesion embolization was primarily performed by coil embolization without stenting (16 cases) and stent-assisted coiling (9 cases). Both techniques had a relatively high rate of at least some technical complication (6 [37.5%] of 16 and 5 [55.6%] of 9, respectively) and major technical complications (i.e., injury, new neurological deficit, or ICA sacrifice) (5 [31.3%] of 16 and 2 [22.2%] of 9, respectively). Endoluminal reconstruction was performed by covered stent (24 cases) and flow diverter (5 cases) placement. Covered stents showed a reasonably high rate of technical complications (10 [41.7%] of 24); however, 8 of these problems were resolved, leaving a small percentage with major technical complications (2 [8.3%] of 24). Flow diverter placement was also well tolerated, with only 1 minor technical complication. CONCLUSIONS Endovascular treatments including vessel sacrifice, coil embolization (with or without stent assistance), and endoluminal reconstruction offer a tailored approach to ICA injury management after endonasal surgery. Vessel sacrifice remains the definitive treatment for acute, uncontrolled bleeding; however, vessel preservation techniques should be considered carefully in select patients. Multiple factors including vascular anatomy, injury characteristics, and risk of dual antiplatelet therapy should guide best treatment, but more study is needed (particularly with flow diverters) to refine this decision-making process. Ideally, all endovascular treatment options should be available at institutions performing endonasal surgery.

[Combined surgical treatment of cavernous internal carotid artery pseudoaneurysm]

We describe a clinical case of surgical treatment of a cavernous internal carotid artery (ICA) pseudoaneurysm that developed due to damage to the artery during transsphenoidal resection of pituitary adenoma. Clinically, the aneurysm presented with episodes of profuse epistaxis that required tight nasal packing. Given the presence of an open circle of Willis, the patient underwent staged surgery that included the creation of a high-flow extra-intracranial anastomosis, subsequent endovascular ICA occlusion at the pseudoaneurysm level using balloon-assisted coiling, and endoscopic debridement of the nasal cavity. The combined surgical treatment of this rare complication successfully excluded the pseudoaneurysm from the bloodstream, which led to complete regression of nasal bleeding.

Internal carotid artery injury in endoscopic endonasal surgery: A systematic review

OBJECTIVES/HYPOTHESIS

Internal carotid artery (ICA) injury during endoscopic endonasal surgery (EES) is a known and feared complication of paranasal sinus and skull base procedures. These ICA injuries can result in stroke, cranial nerve palsies, and death. This review examines the setting of injury along with the treatment approaches, and patient outcomes.

STUDY DESIGN

Systematic review using PubMed/MEDLINE and EMBASE.

METHODS

The databases were searched for articles reporting cases of ICA injury during EES. Variables analyzed included patient demographics, operative approach, preoperative diagnosis, setting of injury, repair method, imaging studies, patient outcomes, and follow-up.

RESULTS

Twenty-five articles with 50 cases were included in this review. The EES approach was used for skull base procedures in 34 cases and for inflammatory disease in 16 cases. The most commonly injured ICA segment was the cavernous (34 cases), followed by the ophthalmic (three cases). Injuries occurred more commonly on the left (1.3:1). Injury occurred in the setting of various steps during EES with instruments. Stereotactic image guidance was reported in two cases. Initial hemostasis was achieved with packing in 35 cases, endoscopic clip sacrifice in four cases, bipolar coagulation with the intent to seal defect in three cases, and bipolar coagulation with the intent to sacrifice the ICA in one case. Intraoperative or immediate postoperative angiography was reported in 27 cases.

CONCLUSIONS

The incidence of reported cases of ICA injury during EES remains low. Left-sided injuries to the cavernous segment of the ICA occurred more frequently than injuries on the right.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:582-590, 2016.

Complications after transsphenoidal surgery for patients with Cushing's disease and silent corticotroph adenomas

OBJECT The purpose of this study was to describe complications associated with the endonasal, transsphenoidal approach for the treatment of adrenocorticotropic hormone (ACTH)-positive staining tumors (Cushing's disease [CD] and silent corticotroph adenomas [SCAs]) performed by 1 surgeon at a high-volume academic medical center. METHODS Medical records from Brigham and Women's Hospital were retrospectively reviewed. Selected for study were 82 patients with CD who during April 2008-April 2014 had consecutively undergone transsphenoidal resection or who had subsequent pathological confirmation of ACTH-positive tumor staining. In addition to demographic, patient, tumor, and surgery characteristics, complications were evaluated. Complications of interest included syndrome of inappropriate antidiuretic hormone secretion, diabetes insipidus (DI), CSF leakage, carotid artery injury, epistaxis, meningitis, and vision changes. RESULTS Of the 82 patients, 68 (82.9%) had CD and 14 (17.1%) had SCAs; 55 patients were female and 27 were male. Most common (n = 62 patients, 82.7%) were microadenomas, followed by macroadenomas (n = 13, 14.7%). A total of 31 (37.8%) patients underwent reoperation. Median follow-up time was 12.0 months (range 3-69 months). The most common diagnosis was ACTH-secreting (n = 68, 82.9%), followed by silent tumors/adenomas (n = 14, 17.1%). ACTH hyperplasia was found in 8 patients (9.8%). Of the 74 patients who had verified tumors, 12 (16.2%) had tumors with atypical features. The overall (CD and SCA) rate of minor complications was 35.4%; the rate of major complications was 8.5% (n = 7). All permanent morbidity was associated with DI (n = 5, 6.1%). In 16 CD patients (23.5%), transient DI developed. Transient DI was more likely to develop in CD patients who had undergone a second operation (37.9%) than in those who had undergone a first operation only (12.8%, p < 0.05). Permanent DI developed in 4 CD patients (5.9%) and 1 SCA patient (7.1%). For 1 CD patient, intraoperative carotid artery injury required endovascular sacrifice of the injured artery, but the patient remained neurologically intact. For another CD patient, aseptic meningitis developed and was treated effectively with corticosteroids. One CD patient experienced major postoperative epistaxis requiring another operative procedure to achieve hemostasis. For 2 CD patients, development of sinus mucoceles was managed conservatively. For 1 SCA patient, an abdominal wound dehisced at the fat graft site. No patients experienced postoperative CSF leakage, visual impairment, or deep vein thrombosis. CONCLUSIONS Transsphenoidal surgery is the treatment of choice for patients with CD and other ACTH-positive staining tumors. Recent advances in endoscopic technology and increasing surgeon comfort with this technology are making transsphenoidal procedures safer, faster, and more effective. Serious complications are uncommon and can be managed successfully.

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.

The endonasal approach for treatment of cerebral aneurysms: A critical review of the literature

The last two decades of neurosurgery have seen flourishing use of the endonasal approach for the treatment of skull base tumors. Safe and effective resections of neoplasms requiring intracranial arterial dissection have been performed using this technique. Recently, there have been a growing number of case reports describing the use of the endonasal approach to surgically clip cerebral aneurysms. We review the use of these approaches in intracranial aneurysm clipping and analyze its advantages, limitations, and consider future directions. Three major electronic databases were queried using relevant search terms. Pertinent case studies of unruptured and ruptured aneurysms were considered. Data from included studies were analyzed. 8 case studies describing 9 aneurysms (4 ruptured and 5 unruptured) treated by the endonasal approach met inclusion criteria. All studies note the ability to gain proximal and distal control and successful aneurysm obliteration was obtained for 8 of 9 aneurysms. 1 intraoperative rupture occurred and was controlled, and delayed complications of cerebrospinal fluid leak, vasospasm, and hydrocephalus occurred in 1, 1, and 2 patients, respectively. Described limitations of this technique include aneurysm orientation and location, the need for lower profile technology, and challenges with handling intraoperative rupture. The endonasal approach for clipping of intracranial aneurysms can be an effective approach in only very select cases as demonstrated clinically and through cadaveric exploration. Further investigation with lower profile clip technology and additional studies need to be performed. Options of alternative therapy, limitations of this approach, and team experience must first be considered.