Avoidance of carotid artery injuries in transsphenoidal surgery with the Doppler probe and micro-hook blades

Anatomical variations of the cavernous Internal Carotid Artery: Validation of an MRI-based classification

OBJECTIVE

Variations of the cavernous Internal Carotid Artery (ICA) angulation (C4-bend) have been classified into 4 anatomical subtypes with particular surgical relevance, as a very angulated ICA comes in closest contact with the pituitary gland leading to higher risk of iatrogenic vascular injury. This study aimed to validate this classification using current routine imaging techniques.

METHODS

The different cavernous ICA bending angles were measured on 109 MRI TOF sequences, within a retrospective database of patients with no sellar lesions. Each ICA was classified into one of 4 anatomical subtypes as already defined in a previous study [1]. Interrater agreement was assessed by a Kappa Correlation Coefficient.

RESULTS

Kappa Correlation Coefficient was of 0.90 [0.82-0.95], validating the strong level of agreement between all observers when using the present classification.

CONCLUSION

Classification of the cavernous ICA in 4 subtypes appears statistically valid on routinely used pre-operative MRI, providing an efficient tool to estimate the vascular iatrogenic risk prior to endoscopic endonasal transsphenoidal surgery.

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.

Surgical complications of endoscopic approach to skull base: analysis of 584 consecutive patients

PURPOSE

Endoscopic techniques have been widely applied for challenging cranial base surgeries in recent years. In this study, we evaluated the safety and efficacy of using the endoscopic endo-nasal route for various skull base pathologies in terms of postoperative complications.

METHODS

A total of 584 consecutive patients who underwent endoscopic skull base surgery were studied. Peri- and post-operative complications and risk factors affecting the occurrence of these complications were evaluated.

RESULTS

648 endoscopic skull base surgical procedures were performed on 584 patients (47.8% females and 52.2% males) with the mean age of 41.2 years. Pituitary adenoma (69.3%) was the most common pathology. Post-operative mortality was 2.0%. The rates of post-operative permanent neurological deficit (one case of 6th nerve injury, two 12th nerve injuries and one hemiparesis) and visual deterioration were 0.6% and 1.5%, respectively. Ten patients (1.7%) were complicated with meningitis and it was the cause of death in 3. Systemic complications not directly attributable to skull base surgical access occurred in 2% (11 patients) with 5 mortalities. The rate of intra-operative vascular injury was 1% and among them one patient died due to PCA injury. The most common post-operative complications were diabetes insipidus (12.5%), anterior pituitary dysfunction (10.6%) and CSF leak (3.6%), respectively. In general, reoperation, malignant lesions, and level IV of surgical complexity were associated with a higher incidence of complications.

CONCLUSION

Endoscopic endo-nasal approach can be a safe and less-morbid first-line treatment of patients with various skull base lesions.

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.

Complication avoidance protocols in endoscopic pituitary adenoma surgery: a retrospective cohort study in 514 patients

PURPOSE

To evaluate the impact of using consistent complication-avoidance protocols in patients undergoing endoscopic pituitary adenoma surgery including techniques for avoiding anosmia, epistaxis, carotid artery injury, hypopituitarism, cerebrospinal fluid leaks and meningitis.

METHODS

All patients undergoing endoscopic adenoma resection from 2010 to 2020 were included. Primary outcomes included 90-day complication rates, gland function outcomes, reoperations, readmissions and length of stay. Secondary outcomes were extent of resection, short-term endocrine remission, vision recovery.

RESULTS

Of 514 patients, (mean age 51 ± 16 years; 78% macroadenomas, 19% prior surgery) major complications occurred in 18(3.5%) patients, most commonly CSF leak (9, 1.7%) and meningitis (4, 0.8%). In 14 of 18 patients, complications were deemed preventable. Four (0.8%) had complications with permanent sequelae (3 before 2016): one unexplained mortality, one stroke, one oculomotor nerve palsy, one oculoparesis. There were no internal carotid artery injuries, permanent visual worsening or permanent anosmia. New hypopituitarism occurred in 23/485(4.7%). Partial or complete hypopituitarism resolution occurred in 102/193(52.8%) patients. Median LOS was 2 days; 98.3% of patients were discharged home. Comparing 18 patients with major complications versus 496 without, median LOS was 7 versus 2 days, respectively p < 0.001. Readmissions occurred in 6%(31/535), mostly for hyponatremia (18/31). Gross total resection was achieved in 214/312(69%) endocrine-inactive adenomas; biochemical remission was achieved in 148/209(71%) endocrine-active adenomas. Visual field or acuity defects improved in 126/138(91.3%) patients.

CONCLUSION

This study suggests that conformance to established protocols for endoscopic pituitary surgery may minimize complications, re-admissions and LOS while enhancing the likelihood of preserving gland function, although there remains opportunity for further improvements.

3 Tesla intra-operative MRI as an adjunct to endoscopic pituitary surgery: an early assessment of clinical utility

BACKGROUND

Extent of resection is a major determinant of outcomes following pituitary surgery. Intra-operative magnetic resonance imaging (iMRI), provides an immediate assessment of the extent of resection, allowing further tumour resection during the same procedure. However, such systems are expensive and significantly increase operative time, prompting some authors to question the additional benefit conferred by iMRI when combined with endoscopy. Our aim was to assess the impact of combining 3 T iMRI with endoscopy in patients with pituitary tumours.

METHODS

We retrospectively reviewed a prospectively maintained database to identify patients who underwent iMRI guided endoscopic resection of pituitary tumours between May 2017 and November 2018 (iMRI cohort). This cohort was compared with a pre-iMRI cohort of patients who underwent endoscopic resection of pituitary adenomas. Operative time, extent of resection, control of endocrine disease and post-operative complications were recorded and analysed.

RESULTS

Thirty-seven patients were included in each cohort. iMRI facilitated additional tumour resection in 6/37 (16%) of cases. In 4/37 cases (11%), iMRI prompted a return to theatre but no further tumour could be identified. The overall GTR rate, following iMRI was 24/37 (65%) as compared to 21/37 (57%) in the pre-iMRI cohort. Cure of endocrine disease associated with hormonally active tumours was achieved in 9/11 (82%) of cases in the iMRI cohort. The mean operative time in the iMRI cohort was 327 minutes (five hours 27 minutes).

CONCLUSIONS

3 T iMRI provides immediate identification of residual tumour following endoscopic pituitary surgery. This allows for resection of surgically accessible residual disease during the same procedure and is likely to reduce the requirement for later re-intervention. However, the use of iMRI in this setting is associated with significant resource allocation issues which must be considered prior to the widespread adoption of this technique.

Streamlining brain tumor surgery care during the COVID-19 pandemic: A case-control study

BACKGROUND

The COVID-19 pandemic forced a reconsideration of surgical patient management in the setting of scarce resources and risk of viral transmission. Herein we assess the impact of implementing a protocol of more rigorous patient education, recovery room assessment for non-ICU admission, earlier mobilization and post-discharge communication for patients undergoing brain tumor surgery.

METHODS

A case-control retrospective review was undertaken at a community hospital with a dedicated neurosurgery and otolaryngology team using minimally invasive surgical techniques, total intravenous anesthesia (TIVA) and early post-operative imaging protocols. All patients undergoing craniotomy or endoscopic endonasal removal of a brain, skull base or pituitary tumor were included during two non-overlapping periods: March 2019-January 2020 (pre-pandemic epoch) versus March 2020-January 2021 (pandemic epoch with streamlined care protocol implemented). Data collection included demographics, preoperative American Society of Anesthesiologists (ASA) status, tumor pathology, and tumor resection and remission rates. Primary outcomes were ICU utilization and hospital length of stay (LOS). Secondary outcomes were complications, readmissions and reoperations.

FINDINGS

Of 295 patients, 163 patients were treated pre-pandemic (58% women, mean age 53.2±16 years) and 132 were treated during the pandemic (52% women, mean age 52.3±17 years). From pre-pandemic to pandemic, ICU utilization decreased from 92(54%) to 43(29%) of operations (p<0.001) and hospital LOS≤1 day increased from 21(12.2%) to 60(41.4%), p<0.001, respectively. For craniotomy cohort, median LOS was 2 days for both epochs; median ICU LOS decreased from 1 to 0 days (p<0.001), ICU use decreased from 73(80%) to 29(33%),(p<0.001). For endonasal cohort, median LOS decreased from 2 to 1 days; median ICU LOS was 0 days for both epochs; (p<0.001). There were no differences pre-pandemic versus pandemic in ASA scores, resection/remission rates, readmissions or reoperations.

CONCLUSION

This experience suggests the COVID-19 pandemic provided an opportunity for implementing a brain tumor care protocol to facilitate safely decreasing ICU utilization and accelerating discharge home without an increase in complications, readmission or reoperations. More rigorous patient education, recovery room assessment for non-ICU admission, earlier mobilization and post-discharge communication, layered upon a foundation of minimally invasive surgery, TIVA anesthesia and early post-operative imaging are possible contributors to these favorable trends.

Pituitary adenomas in older adults (≥ 65 years): 90-day outcomes and readmissions: a 10-year endoscopic endonasal surgical experience

INTRODUCTION

Longer lifespan and newer imaging protocols have led to more older adults being diagnosed with pituitary adenomas. Herein, we describe outcomes of patients ≥ 65 years undergoing endoscopic adenoma removal. To address selection criteria, we also assess a conservatively managed cohort.

METHODS

A retrospective analysis of 90-day outcomes of patients undergoing endoscopic pituitary adenomectomy from 2010 to 2019 by a neurosurgical/ENT team was performed. Tumor subtype, cavernous sinus invasion, extent of resection/early remission, endocrinology outcomes, complications, re-operations and readmissions were analyzed. A comparator cohort ≥ 65 years undergoing clinical surveillance without surgery was also analyzed.

RESULTS

Of 468 patients operated on for pituitary adenoma, 123 (26%) were ≥ 65 years (range 65-93 years); 106 (86.2%) had endocrine-inactive adenomas; 18 (14.6%) had prior surgery. Of 106 patients with endocrine-inactive adenomas, GTR was achieved in 70/106 (66%). Of 17 patients with endocrine-active adenomas, early biochemical remission was: Cushing's 6/8; acromegaly 1/4; prolactinomas 1/5. Gland function recovery occurred in 28/58 (48.3%) patients with various degrees of preoperative hypopituitarism. New anterior hypopituitarism occurred in 3/110 (2.4%) patients; permanent DI in none. Major complications in 123 patients were: CSF leak 2 (1.6%), meningitis 1 (0.8%), vision decline 1 (0.8%). There were no vascular injuries, operative hematomas, anosmia, deaths, MIs, or thromboembolic events. Median length of stay was 2 days. Readmissions occurred in 14/123 (11.3%) patients, 57% for delayed hyponatremia. Intra-cohort analysis by age (65-69, 70-74, 75-79,  ≥ 80 years) revealed no outcome differences. Cavernous sinus invasion (OR 7.7, CI 1.37-44.8; p = 0.02) and redo-surgery (OR 8.5, CI 1.7-42.8; p = 0.009) were negative predictors for GTR/NTR. Of 105 patients evaluated for presumed pituitary adenoma beginning in 2015, 72 (69%) underwent surgery, 8 (7%) had prolactinomas treated with cabergoline and 25 (24%) continue clinical surveillance without surgery, including two on new hormone replacement.

CONCLUSION

This study suggests that elderly patients carefully selected for endoscopic adenoma removal can have excellent short-term outcomes including high resection rates, low complication rates and short length of stay. Our experience supports a multidisciplinary approach and the concept of pituitary centers of excellence. Based on our observations, approximately 25% of elderly patients with pituitary adenomas referred for possible surgery can be monitored closely without surgery.

The use of an O-arm in endonasal endoscopic operations of the skull base

Background

Endoscopic endonasal transsphenoidal approaches are broadly used nowadays for a vast spectrum of pathologies sited in the anterior and middle cranial fossa. The usage of neuronavigation systems (neuronavigation) in these surgeries is crucial for improving orientations deeply inside the skull and increasing patient safety.

Methods

The aim of this study was to assess the use of optical neuronavigation, together with an intraoperative O-arm O2 imaging system, in a group of patients with hypophyseal adenoma that underwent a transnasal transsphenoidal surgery, and correlate the accuracy and its deviation during the navigational process against the use of conventional neuronavigation that uses preoperative MRI and CT scans. The overall group consisted of six patients, between 39 and 78 years old, with a diagnosis of hypophyseal adenoma. Patients were treated with an endoscopic transsphenoidal technique and all of them underwent preoperative MRI and CT scans of the brain. These images were used in the neuronavigation system StealthStation S7^® during the surgery, where we defined two bony anatomical landmarks, such as a vomer or the origin of an intrasphenoidal septum, in each operated patient. The tip of the navigational instrument, under endoscopic control, pointed to these landmarks and the distance between the tip and the bony structure was measured on the neuronavigation system. Afterwards, intraoperative 3D x-ray imaging was performed via the mobile system O-arm O2^® system with automatic transfer into the navigational system. Under endoscopic guidance, we localized the identical bony anatomical landmarks used in the previous measurement and re-measured the distance between the tip and bony landmark in images acquired by the O-arm. The results of both measurements were statistically compared.

Results

The mean error of accuracy during conventional neuronavigation with usage of preoperative CT and MRI scans was 2.65 mm. During the neuronavigation, with utilization of intraoperative 3D O-arm images, the mean error of accuracy 0 mm. These mean errors of accuracy (both measurement methods were compared by nonparametric Wilcoxon test) had a statistically significant difference (p = 0.043).

Conclusions

Based on this preliminary clinical study, we conclude that the O-arm is capable of providing intraoperative x-ray 3D images in sufficient spatial resolution in a clinically feasible acquisition. The mean error of accuracy during intraoperative navigation, based on 3D O-arm scans at the skull base, is significantly lower compared to the usage of navigation using conventional presurgical CT and MRI images. This suggests the suitability of this method for utilization during endoscopic endonasal skull base approaches.

Assessment of Factors Associated With Internal Carotid Injury in Expanded Endoscopic Endonasal Skull Base Surgery

Importance

Injury to the internal carotid artery (ICA) during endoscopic endonasal skull base surgery does not typically occur as an isolated circumstance but often is the result of multiple factors.

Objective

To assess the factors associated with ICA injury in an effort to reduce its occurrence.

Design, Setting, and Participants

This quality improvement study used a multicenter root cause analysis of ICA injuries sustained during endoscopic endonasal skull base surgery performed at 11 tertiary care centers across 4 continents (North America, South America, Europe, and Asia) from January 1, 1993, to December 31, 2018. A fishbone model was built to facilitate the root cause analysis. Patients who underwent an expanded endoscopic endonasal approach that carried a substantial potential risk of an ICA injury were included in the analysis. A questionnaire was completed by surgeons at the centers to assess relevant human, patient, process, technique, instrument, and environmental factors associated with the injury.

Main Outcomes and Measures

Root cause analysis of demographic, human, patient, process, technique, instrument, and environmental factors as well as mortality and morbidity data.

Results

Twenty-eight cases of ICA injury occurred during 7160 expanded endoscopic endonasal approach procedures (incidence of 0.4%). The mean age of the patients was 49 years, with a female to male predominance ratio of 1.8:1 (18 women to 10 men). Anatomical (23 [82%]), pathological (15 [54%]), and surgical resection (26 [93%]) factors were most frequently reported. The surgeon's mental or physical well-being was reported as inadequate in 4 cases (14%). Suboptimal imaging was reported in 6 cases (21%). The surgeon's experience level was not associated with ICA injury. The ICA injury was associated with use of powered or sharp instruments in 20 cases (71%), and use of new instruments or technology in 7 cases (25%). Two patients (7%) died in the operating room, and 3 (11%) were alive with neurological deficits. Overall, patient-related factors were the most frequently reported risk factors (in 27 of 28 cases [96%]). Factors associated with ICA injury catalyzed a list of preventive recommendations.

Conclusions and Relevance

This study found that human factors were associated with intraoperative ICA injuries; however, they were usually accompanied by other deficiencies. These findings suggest that identifying risk factors is crucial for preventing such injuries. Preoperative planning and minimizing the potential for ICA injury also appear to be essential.

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.

Transsphenoidal approach in children with partially or minimally developed sphenoid sinus

OBJECT

The transsphenoidal approach is guided by a few fundamental anatomic landmarks. Pneumatization of the SS is variable, and this plays a key role in accessing the sella floor and other skull base structures. It may be absent or minimally present in both adult and, often, pediatric population, making surgical approach more difficult than usual. We aim to demonstrate that also in the more difficult cases, with a minimal level of pneumatization, the transsphenoidal approach is still possible especially with the support of neuronavigation and intraoperative magnetic resonance imaging (iMRI).

METHODS

We present our experience accumulated after the treatment of 6 children with minimally pneumatized sphenoid sinus describing the workflow to access the sella floor.

RESULTS

No perioperative complications due to the surgical approach were observed, and no cases of mortality were reported. After the surgery, the visual field deficit improved in 1 patient and remained stable in three patients. No postoperative new neurologic deficits were found. No cases of cerebrospinal fluid (CSF) leak were observed.

CONCLUSIONS

The transsphenoidal approach can be safely used even in cases of minimally or even absent pneumatization of SS as in young children. In order to have a safe approach in such patients, the use of tools, such as navigation system and iMRI, is recommended. Furthermore, the iMRI allows to avoid exposure to radiation as in case of fluoroscopy.

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.

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.

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.

Review of the main surgical and angiographic-oriented classifications of the course of the internal carotid artery through a novel interactive 3D model

The course of the internal carotid artery (ICA) and its segment classifications were reviewed by means of a new and freely available 3D interactive model of the artery and the skull base, based on human neuroimages, that can be freely downloaded at the Public Repository of the University of Barcelona (http://diposit.ub.edu/dspace/handle/2445/112442) and runs under Acrobat Reader in Mac and Windows computers and Windows 10 tablets. The 3D-PDF allows zoom, rotation, selective visualization of structures, and a predefined sequence view. Illustrative images of the different classifications were obtained. Fischer (Zentralbl Neurochir 3:300-313, 1938) described five segments in the opposite direction to the blood flow. Gibo-Rothon (J Neurosurg 55:560-574, 1981) follow the blood flow, incorporated the cervical and petrous portions, and divided the subarachnoid course-supraclinoid-in ophthalmic, communicating, and choroidal segments, enhancing transcranial microscopic approaches. Bouthillier (Neurosurgery 38:425-433, 1996) divided the petrous portion describing the lacerum segment (exposed in transfacial procedures and exploration of Meckel's cave) and added the clinoid segment between the proximal and distal dural rings, of interest in cavernous sinus surgery. The Kassam's group (2014), with an endoscopic endonasal perspective, introduces the "paraclival segment," including the "lacerum segment" and part of the intracavernous ICA, and details surgical landmarks to minimize the risk of injury. Other classifications are also analyzed. This review through an interactive 3D tool provides virtual views of the ICA and becomes an innovative perspective to the segment classifications and neuroanatomy of the ICA and surrounding structures.

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.

[Endoscopic transsphenoidal resection of pituitary adenomas invading the cavernous sinus]

INTRODUCTION

Pituitary adenomas are benign growths that invade the cavernous sinus (CS) in 10-15% of cases. There are different types of microsurgical and endoscopic approaches enabling resection of tumors from the CS cavity that is a relatively small and hard to reach anatomical structure comprising eloquent neurovascular structures.

MATERIAL AND METHODS

A study group included 97 patients with pituitary adenomas (PAs) invading the CS. PAs were resected using an endoscopic technique: adenomas were resected from the CS cavity through a standard endoscopic endonasal transsphenoidal approach in 62 cases; a lateral extended transsphenoidal endoscopic approach was used in 35 cases. A control group included patients with PAs spreading into the laterosellar region who were operated on using microsurgical extra-intradural (n=14) and transsphenoidal (n=149) approaches. In the study group, the degree of PA invasion into the CS cavity was determined using the Knosp scale.

RESULTS

In the study group, total tumor resection was achieved in 49 (50.5%) cases, subtotal resection in 39 (40.2%) cases, and partial resection in 9 (9.3%) patients. In the case of visual disorders (n=70), vision improvement was achieved in 41.4% of cases. Vision deterioration was detected in 11.4% of cases; no vision changes were in 47.1% of cases. Patients (27.8%) who had not had visual impairments before surgery had no negative changes in vision in the postoperative period. The development/augmentation of oculomotor disorders in the study group occurred in 14 (14.4%) cases. In the study group, hormonal remission of the disease in patients with hormone-active PAs was in 26.7% of cases (n=12). There were no cases of nasal liquorrhea, meningitis, and death in the study group.

CONCLUSION

Endoscopic endonasal transsphenoidal resection of PAs invading the CS is a more efficient and safer surgical technique compared to microsurgical techniques (transsphenoidal and extra-intradural approach). The lateral extended transsphenoidal endoscopic approach enables resection of PAs with massive invasion into the CS (Grade III and Grade IV, Knosp scale) and has less postoperative complications compared to the extra-intradural approach (p<0.05).

Parasellar Extension Grades and Surgical Extent in Endoscopic Endonasal Transsphenoidal Surgery for Pituitary Adenomas : A Single Surgeon's Consecutive Series with the Aspects of Reliability and Clinical Validity

Objective

The inter-rater reliability of the modified Knosp's classification was measured before the analysis. The clinical validity of the parasellar extension grading system was evaluated by investigating the extents of resection and complication rates among the grades in the endoscopic endonasal transsphenoidal surgery (EETS) for pituitary adenomas.

Methods

From November 2008 to August 2015, of the 286 patients who underwent EETS by the senior author, 208 were pituitary adenoma cases (146 non-functioning pituitary adenomas, 10 adrenocorticotropic hormone-secreting adenomas, 31 growth hormone-secreting adenomas, 17 prolactin-secreting adenomas, and 4 thyroid-stimulating hormone-secreting adenomas; 23 microadenomas, 174 macroadenomas, and 11 giant adenomas). Two neurosurgeons and a neuroradiologist independently measured the degree of parasellar extension on the preoperative sellar MRI according to the modified Knosp's classification. Inter-rater reliability was statistically assessed by measuring the intraclass correlation coefficient. The extents of resection were evaluated by comparison of the pre- and post-operative MR images; the neurovascular complications were assessed by reviewing the patients' medical records. The extent of resection was measured in each parasellar extension grade; thereafter, their statistical differences were calculated.

Results

The intraclass correlation coefficient value of reliability across the three raters amounted to 0.862. The gross total removal (GTR) rates achieved in each grade were 70.0, 69.8, 62.9, 21.4, 37.5, and 4.3% in Grades 0, 1, 2, 3A, 3B, and 4, respectively. A significant difference in the extent of resection was observed only between Grades 2 and 3A. In addition, significantly higher complication rates were observed in the groups above Grade 3A.

Conclusion

Although the modified Knosp's classification system appears to be complex, its inter-rater reliability proves to be excellent. Regarding the clinical validity of the parasellar extension grading system, Grades 3A, 3B, and 4 have a negative predictive value for the GTR rate, with higher complication rates.

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.

Proposed clinical internal carotid artery classification system

INTRODUCTION

Numerical classification systems for the internal carotid artery (ICA) are available, but modifications have added confusion to the numerical systems. Furthermore, previous classifications may not be applicable uniformly to microsurgical and endoscopic procedures. The purpose of this study was to develop a clinically useful classification system.

MATERIALS AND METHODS

We performed cadaver dissections of the ICA in 5 heads (10 sides) and evaluated 648 internal carotid arteries with computed tomography angiography. We identified specific anatomic landmarks to define the beginning and end of each ICA segment.

RESULTS

The ICA was classified into eight segments based on the cadaver and imaging findings: (1) Cervical segment; (2) cochlear segment (ascending segment of the ICA in the temporal bone) (relation of the start of this segment to the base of the styloid process: Above, 425 sides [80%]; below, 2 sides [0.4%]; at same level, 107 sides [20%]; P < 0.0001) (relation of cochlea to ICA: Posterior, 501 sides [85%]; posteromedial, 84 sides [14%]; P < 0.0001); (3) petrous segment (horizontal segment of ICA in the temporal bone) starting at the crossing of the eustachian tube superolateral to the ICA turn in all 10 samples; (4) Gasserian-Clival segment (ascending segment of ICA in the cavernous sinus) starting at the petrolingual ligament (PLL) (relation to vidian canal on imaging: At same level, 360 sides [63%]; below, 154 sides [27%]; above, 53 sides [9%]; P < 0.0001); in this segment, the ICA projected medially toward the clivus in 275 sides (52%) or parallel to the clivus with no deviation in 256 sides (48%; P < 0.0001); (5) sellar segment (medial loop of ICA in the cavernous sinus) starting at the takeoff of the meningeal hypophyseal trunk (ICA was medial into the sella in 271 cases [46%], lateral without touching the sella in 127 cases [23%], and abutting the sella in 182 cases [31%]; P < 0.0001); (6) sphenoid segment (lateral loop of ICA within the cavernous sinus) starting at the crossing of the fourth cranial nerve on the lateral aspect of the cavernous ICA and located directly lateral to the sphenoid sinus; (7) ring segment (ICA between the 2 dural rings) starting at the crossing of the third cranial nerve on the lateral aspect of the ICA; (8) cisternal segment starting at the distal dural ring.

CONCLUSIONS

The classification may be applied uniformly to all skull base surgical approaches including lateral microsurgical and ventral endoscopic approaches, obviating the need for 2 separate classification systems. The classification allows extrapolation of relevant clinical information because each named segment may indicate potential surgical risk to specific structures.

Role of Endoscopic Skull Base and Keyhole Surgery for Pituitary and Parasellar Tumors Impacting Vision

Significant advances over the last 2 decades in imaging technology, instrumentation, anatomical knowledge, and reconstructive techniques have resulted in the endonasal endoscopic approach becoming an integral part of modern skull base surgery. With growing use and greater experience, surgical outcomes continue to incrementally improve across many skull base pathologies, including those tumors that impact vision and ocular motility. The importance of the learning curve and use of a multi-disciplinary approach is critical to maximizing success, minimizing complications, and enhancing quality of life in these patients. Realizing the limits of the endonasal route and reasonable use of transcranial approaches such as the supraorbital eyebrow craniotomy, it may br appropriate to consider nonsurgical therapy including various forms of radiotherapy [corrected] and medical treatment options.

Complications Related to the Endoscopic Endonasal Transsphenoidal Approach for Nonfunctioning Pituitary Macroadenomas in 300 Consecutive Patients

OBJECTIVE

To analyze complications of endoscopic transsphenoidal surgery (ETS) for nonfunctioning pituitary macroadenomas (NFPAs).

METHODS

A retrospective study of 300 NFPAs was performed. Complications and factors that could influence these complications were analyzed.

RESULTS

Visual and pituitary functions worsened in 2.4% and 13.7% of cases, respectively. Postoperative diabetes insipidus was permanent in 6.2% of cases. Postoperative meningitis occurred in 3.3% of patients. Meningitis was strongly associated with intraoperative cerebrospinal fluid (CSF) leaks (P = 0.01), postoperative CSF leaks (P = 0.0001), and operation times longer than 1 hour (P = 0.023). Detection of Staphylococcus aureus and preoperative treatment with mupirocin in the nostrils did not impact the occurrence of meningitis. Two patients with meningitis died (unique causes of death). Postoperative CSF leaks occurred in 2.7% of cases and were associated with intraoperative CSF leaks (P = 0.007) and permanent diabetes insipidus (P = 0.028). The rate of CSF leak decreased from 4% to 0.8% (P = 0.048) after we moved from a soft to hard reconstruction of the sella. The rate of postoperative epistaxis decreased from 6.7% to 1.25% after we stopped using monopolar coagulation (P = 0.013).

CONCLUSIONS

ETS permits a wide view, allowing good conditions for a satisfactory resection in the majority of NFPAs. Some pitfalls of endoscopy can lead to complications that improve with modification of the operative technique (i.e., CSF leak and postoperative epistaxis). This study confirms an acceptable rate of complications associated with ETS.

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.

[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.

The use of intraoperative Doppler ultrasound in endoscopic transsphenoidal surgery

INTRODUCTION

Doppler ultrasound (DUS) has been widely used in neurosurgical practice to diagnose various cerebrovascular diseases. This technique is used in transsphenoidal surgery to identify the localization of intracranial arteries when making an approach or during tumor resection.

MATERIAL AND METHODS

To identify the cavernous segment of the internal carotid artery (ICA) and/or basilar artery during endoscopic transsphenoidal surgery, we used a combined device on the basis of a click line curette («Karl Storz») and a 16 MHz Doppler probe (Lassamed). The technique was used in 51 patients during both standard transsphenoidal surgery (23 cases) and transsphenoidal tumor resection through an extended approach (28 cases).

RESULTS AND DISCUSSION

Doppler ultrasound was used in different situations: to determine a trajectory of the endonasal transsphenoidal approach in the absence of the normal anatomical landmarks (16 cases), to define the limits of safe resection of a tumor located in the laterosellar region (7), and to implement an extended transsphenoidal endoscopic approach (28). Intraoperative Doppler ultrasound enabled identification of the cavernous segment of the internal carotid artery in 45 cases and the basilar artery in 2 cases; a blood vessel was not found in 4 cases. Injury to the cavernous segment of the internal carotid artery was observed only in 1 case.

CONCLUSION

The use of the described combined device in transsphenoidal surgery turned Doppler ultrasound into an important and useful technique for visualization of the ICA within the tumor stroma as well as in the case of the changed skull base anatomy. Its use facilitates manipulations in a deep and narrow wound and enables inspection of the entire surface of the operative field in various planes, thereby surgery becomes safer due to the possibility of maximum investigation of the operative field.

Novel Techniques in the Surgical Treatment of Acromegaly: Applications and Efficacy

Since the establishment of transsphenoidal microsurgery as the operative treatment of choice in most patients with acromegaly 40 years ago, a few novel technical developments have evolved. Their application, utility and efficacy will be briefly discussed in this review article, based on an analysis of published results and the authors' personal experience. The endoscope was additionally used to search for residual tumours in locations which could not be visualised with the operating microscope. In many centres it has by now fully replaced the operating microscope. Extended endoscopic operations hardly have limits in respect to accessible pathology. Overall, the results and complications reported from microsurgical and endoscopic series are comparable. Intraoperative magnetic resonance imaging allows depicting the completeness of a tumour resection. While in many patients additional tumour resections are performed on the basis of intraoperative imaging, the improvements in hormonal remission rates reported are less impressive. Neuronavigation uses imaging data to improve the surgeon's orientation, and it is certainly a major asset to the inexperienced. In high-caseload centres it is mainly appreciated in anatomical variants and reoperations. While the Doppler probe is a valuable and easily affordable gadget to avoid vascular arterial injury, intraoperative ultrasound imaging of tumour extension has a much poorer resolution than magnetic resonance imaging and is thus not widely implemented. The clinical value of intraoperative growth hormone measurements is controversially discussed. In summary, the application of modern technology has only led to a minor improvement of results, but it has widened the spectrum of accessible pathologies and increased the safety of the procedures for the patient. It is expected that outcomes will continue to improve as novel techniques and concepts are being developed.

Evolution of minimally invasive approaches to the sella and parasellar region

Introduction Given advancements in endoscopic image quality, instrumentation, surgical navigation, skull base closure techniques, and anatomical understanding, the endonasal endoscopic approach has rapidly evolved into a widely utilized technique for removal of sellar and parasellar tumors. Although pituitary adenomas and Rathke cleft cysts constitute the majority of lesions removed via this route, craniopharyngiomas, clival chordomas, parasellar meningiomas, and other lesions are increasingly removed using this approach. Paralleling the evolution of the endonasal route to the parasellar region, the supraorbital eyebrow craniotomy has also been increasingly used as an alternative minimally invasive approach to reach this skull base region. Similar to the endonasal route, the supraorbital route has been greatly facilitated by advances in endoscopy, along with development of more refined, low-profile instrumentation and surgical navigation technology.

Objectives This review, encompassing both transcranial and transsphenoidal routes, will recount the high points and advances that have made minimally invasive approaches to the sellar region possible, the evolution of these approaches, and their relative indications and technical nuances.

Data Synthesis The literature is reviewed regarding the evolution of surgical approaches to the sellar region beginning with the earliest attempts and emphasizing technological advances, which have allowed the evolution of the modern technique. The surgical techniques for both endoscopic transsphenoidal and supraorbital approaches are described in detail. The relative indications for each approach are highlighted using case illustrations.

Conclusions Although tremendous advances have been made in transitioning toward minimally invasive transcranial and transsphenoidal approaches to the sella, further work remains to be done. Together, the endonasal endoscopic and the supraorbital endoscope-assisted approaches are complementary minimally invasive routes to the parasellar region.

The expanding role of the endonasal endoscopic approach in pituitary and skull base surgery: A 2014 perspective

BACKGROUND

The past two decades have been the setting for remarkable advancement in endonasal endoscopic neurosurgery. Refinements in camera definition, surgical instrumentation, navigation, and surgical technique, including the dual surgeon team, have facilitated purely endonasal endoscopic approaches to the majority of the midline skull base that were previously difficult to access through the transsphenoidal microscopic approach.

METHODS

This review article looks at many of the articles from 2011 to 2014 citing endonasal endoscopic surgery with regard to approaches and reconstructive techniques, pathologies treated and outcomes, and new technologies under consideration.

RESULTS

Refinements in approach and closure techniques have reduced the risk of cerebrospinal fluid leak and infection. This has allowed surgeons to more aggressively treat a variety of pathologies. Four main pathologies with outcomes after treatment were identified for discussion: pituitary adenomas, craniopharyngiomas, anterior skull base meningiomas, and chordomas. Within all four of these tumor types, articles have demonstrated the efficacy, and in certain cases, the advantages over more traditional microscope-based techniques, of the endonasal endoscopic technique.

CONCLUSIONS

The endonasal endoscopic approach is a necessary tool in the modern skull base surgeon's armamentarium. Its efficacy for treatment of a wide variety of skull base pathologies has been repeatedly demonstrated. In the experienced surgeon's hands, this technique may offer the advantage of greater tumor removal with reduced overall complications over traditional craniotomies for select tumor pathologies centered near the midline skull base.

Surgical Treatment of Inadvertent Internal Carotid Artery Lesion by Extraintracranial High-flow Bypass. A Case Report and Review of the Literature

Internal carotid artery (ICA) injury following transsphenoidal surgery is a rare but potentially fatal complication. Usually, endovascular occlusion of the ICA or stent graft placement is the treatment of these vascular complications described in literature. We present a case of ICA perforation during transsphenoidal surgery in a patient with limited collateral cerebral blood flow and with ectasia of the ICA that rule out an endovascular treatment. We report the surgical revascularization via high-flow extra-intracranial radial artery bypass and consicutive artery ligation.

Pro: endoscopic endonasal transsphenoidal pituitary surgery is superior to microscope-based transsphenoidal surgery

The introduction of the endoscope to transsphenoidal pituitary surgery is relatively new, but represents a major advancement in the field. The use of the endoscope to visualize the sella via a direct endonasal approach offers the surgeon dramatically better visualization as well as improved range of motion compared to the operating microscope. Growing evidence confirms that these improvements directly translate into better surgical resections and outcomes. Further, patient comfort and satisfaction are higher with the endonasal method compared with other transsphenoidal approaches, and it is a cost effective technology. This position paper will outline the reasons that endoscopic endonasal transsphenoidal surgery is the preferred method for pituitary surgery, and why it will likely be adopted as the standard technique for transsphenoidal surgery worldwide.

Cerebrovascular complications and utilization of endovascular techniques following transsphenoidal resection of pituitary adenomas: a study of the Nationwide Inpatient Sample 2001-2010

PURPOSE

Cerebrovascular complications following transsphenoidal resection of pituitary tumors are rare and often evaluated and treated with endovascular techniques. We determined the utilization rate and outcomes of endovascular procedures in transsphenoidal pituitary resection patients using an administrative database.

METHODS

Using the Nationwide Inpatient Sample 2001-2010, patients receiving transsphenoidal resection of benign pituitary tumors were identified. The rate of cerebrovascular complications and utilization of endovascular repair procedures and cerebral angiography were compared between high (≥ 75 procedures/year) and low volume (<75 procedures/year) centers. Chi squared tests were used to compare categorical variables.

RESULTS

70,878 were patients included in this study. ICH/SAH occurred in 0.9 % of patients (652/70,878) and stroke occurred in 0.5 % of patients (327/70,878). Patients treated at high volume centers had significantly lower rates of stroke (0.5 % vs. 1.0 %, P = 0.04), and ICH/SAH (0.5 vs. 1.0 %, P = 0.05) when compared to patients treated at low-volume centers. Overall, 531 patients (0.7 %) received post-operative angiography and 83 patients (0.1 %) received endovascular repair procedures. High volume center patients underwent angiography in 0.4 % of cases compared to 0.9 % for low volume center patients (P = 0.02). There was no significant difference in endovascular repair procedure rates at high and low volume centers (0.1 vs. 0.2 %, P = 0.37).

CONCLUSIONS

Cerebrovascular surgical complications requiring cerebral angiography and endovascular repair are rare among transsphenoidal pituitary resection patients. These occur with higher frequency at low volume centers and are associated with high mortality rates.

Delayed cavernous carotid artery pseudoaneurysm caused by absorbable plate following transsphenoidal surgery: case report and review of the literature

Background Bioabsorbable plates are frequently utilized in the repair of skull base defects following transsphenoidal operations. Traumatic intracranial pseudoaneurysms are a rare complication of transsphenoidal surgery. To date, iatrogenic carotid pseudoaneurysm associated with the use of an absorbable plate has been reported once. Results A 57-year-old man with a large nonfunctional pituitary macroadenoma underwent an endoscopic transsphenoidal operation with gross total resection. An absorbable plate was placed extradurally to reconstruct the sellar floor. He experienced delayed repeated epistaxis, followed by a right middle cerebral artery distribution embolic stroke. Computed tomorgraphy (CT) angiogram 6 weeks postoperatively revealed a 6 × 4 mm pseudoaneurysm located on the medial wall of the right cavernous internal carotid artery. Stent coiling was used to successfully obliterate the pseudoaneurysm, and the patient fully recovered. Conclusion Delayed erosion of the carotid artery wall caused by a plate used to reconstruct the sellar floor may manifest with epistaxis or embolic stroke. The authors' preference is to avoid insertion of a rigid plate for sellar floor reconstruction in the absence of intraoperative cerebrospinal fluid (CSF) leaks, unless it is required to buttress a large skull base defect. Short-segment embolization with stent coiling is the preferred treatment option for carotid pseudoaneurysms following transsphenoidal operations.

Accuracy of Surgeon's Estimation of Sella Margins during Endoscopic Surgery for Pituitary Adenomas: Verification Using Neuronavigation

We assessed the accuracy of a surgeon's localization of sella margins during endoscopic transsphenoidal surgery for pituitary adenomas, as verified using a neuronavigational system, and we identify types of pathology in which neuronavigation is of most benefit. We performed a prospective cohort study of 32 consecutive patients undergoing image-guided endoscopic transsphenoidal surgery for pituitary adenomas. We assessed the margin of error in the surgeon's localization of the superior and inferior margins of the sella and the lateral margins as determined by the medial border of left and right carotid arteries, using a magnetic resonance-based neuronavigational system. The overall mean error of localization of sella margins by the surgeon was 4.5 ± 3 mm. Localization of the inferior sella margin was more accurate (3.1 ± 2 mm mean error) compared with localization of the left (4.8 ± 3 mm) or right carotid arteries (4.6 ± 3 mm). Giant adenomas (> 2.5 cm), more invasive adenomas (Hardy grade IV), and those with parasellar extension (Hardy grades D and E) were associated with larger errors in localization of the carotid arteries. There was no significant difference when stratifying for recurrent surgery, nostril of approach, and sella morphology. During endoscopic transsphenoidal surgery, the margin of error in the surgeon's estimation of the sella margins for adenomas less than 2.5 cm located predominantly within the sella is relatively small. The margin of error increases for giant adenomas, with greater invasiveness and parasellar spread, and the use of neuronavigation can be especially useful in such cases.

Anatomical aspects in the transsphenoidal-transethmoidal approach to the optic canal: an anatomic-cadaveric study

BACKGROUND

Determining anatomic landmarks during a transsphenoidal-transethmoidal approach to the optic canal region is of critical importance.

METHODS

Sella-parasella sphenoid bone blocks were extracted from adult cadavers. Anatomic dissections were performed in the optic canal region using a surgical microscope in 30 samples. Quantitative measurements were done using photographic techniques. For histological evaluation, coronal and longitudinal cross-sections were taken from the bilateral optic canal in seven decalcified samples.

RESULTS

Optic protuberance (OP), carotid protuberance (CP), medial opticocarotid recess (MOCR) and lateral opticocarotid recess (LOCR) were defined as lateral landmarks determining the width of the opening in the extended transsphenoidal-transethmoidal approach. Among all anatomic markers, LOCR was the most determinant lateral marker with tubercular recess the most prominent central marker. OPs showing the optic canal direction and inter-recessal sulci had similar distinguishing rates in the sphenoid sinus base. Inter-recessal sulci formed by OPs and CPs were observed between MOCR and LOCR in most samples. In histologic sections, the dural sheath was thicker inferolaterally to the optic nerve compared to superiorly and medially; collagen arrangement was dense and irregular.

CONCLUSION

Although LOCRs and tubercular recesses are safe and prominent markers in extended transsphenoidal-transethmoidal approaches, other anatomic markers should also be taken into consideration to perform an efficient optic canal approach and optic canal decompression. Other factors for safe dissection are the length of the optic canal, bone thickness, adherence of dural structures and the course of the intradural ophthalmic artery.

Carotid artery injury after endonasal surgery

Carotid artery injury during endonasal surgery is the most feared and catastrophic complication. Internal carotid artery injury is more frequent during skull base surgery, and risk factors include acromegaly, previous revision surgery, and prior radiotherapy and bromocriptine therapy. Nasal packing is frequently used to gain hemostasis, often resulting in vascular occlusion. Recent research recommends the crushed muscle patch treatment as an effect hemostat that maintains vascular patency. Endovascular techniques are recommended for vascular control and complication management. Coil or balloon embolization is preferred in patients with adequate collateral cerebral blood flow, and stent-graft placement or bypass surgery is indicated in those who do not.

Clinical significance of MRI-aided measurements in the transsphenoidal approach in Chinese adults

To determine the optimal direction for approaching sellar tumors, we developed an anatomical model of the most common approach, the transsphenoidal approach, in Chinese adults by analyzing MRI-aided measurements. Craniocerebral MRI of 75 Chinese adults with pituitary tumors and 238 healthy Chinese adults were obtained to analyse the angle between the direction of the transsphenoidal approach and the reference line linking the glabella and the external occipital tubercle, the approach depth, and the distance between the internal carotid arteries (ICA) at the cavernous sinuses segment. The mean angle (± standard deviation [SD]) between the direction of the transsphenoidal approach and the reference line in patients with sellar tumors was 40.51 ± 2.98°, similar to the angle in the healthy control group (41.18 ± 3.35°) (p > 0.05). The mean depth (± SD) calculated via the transsphenoidal approach in the sellar tumor group was 86.01 ± 4.99 mm, which was similar to the control group (85.34 ± 4.96 mm) (p > 0.05). However, the mean distance (± SD) between the bilateral ICA at the cavernous sinuses in the patients with sellar tumors was 22.68 ± 5.03 mm, greater than in the control group (15.89 ± 3.11 mm) (p < 0.01). Thus, during sellar tumor resection via the transsphenoidal approach, the patient's head should be first positioned to allow the line linking the glabella and the external occipital tubercle to be perpendicular to the horizontal plane, and then inclined backwards at an angle of about 40°. The floor of the sella, at a depth of about 85 mm, can then be reached vertically by introducing a speculum via a single nostril. The operative field should be limited to about 1cm from the midline. By adopting this method, the optimal angle and depth of the transsphenoidal approach can be determined without complicated equipment. Moreover, this technique is simple and accurate enough to maintain the correct approach, locate the lesion, and reduce the incidence of serious postoperative complications, including bleeding caused by rupture of the ICA.

The neurosurgical anatomy of the sphenoid sinus and sellar floor in endoscopic transsphenoidal surgery

OBJECT

A considerable degree of variability exists in the anatomy of the sphenoid sinus, sella turcica, and surrounding skull base structures. The authors aimed to characterize neuroimaging and intraoperative variations in the sagittal and coronal surgical anatomy of healthy controls and patients with sellar lesions.

METHODS

Magnetic resonance imaging studies obtained in 100 healthy adults and 78 patients with sellar lesions were reviewed. The following measurements were made on midline sagittal images: sellar face, sellar prominence, sellar angle, tuberculum sellae angle, sellar-clival angle, length of planum sphenoidale, and length of clivus. The septal configuration of the sphenoid sinus was classified as either simple or complex, according to the number of septa, their symmetry, and their morphological features. The following measurements were made on coronal images: maximum width of the sphenoid sinus and sellar face, and the distance between the parasellar and midclivus internal carotid arteries. Neuroimaging results were correlated with intraoperative findings during endoscopic transsphenoidal surgery.

RESULTS

Three sellar floor morphologies were defined in normal adults: prominent (sellar angle of < 90°) in 25%, curved (sellar angle 90-150°) in 63%, flat (sellar angle > 150°) in 11%, and no floor (conchal sphenoid) in 1%. In healthy adults, the following mean measurements were obtained: sellar face, 13.4 mm; sellar prominence, 3.0 mm; sellar angle, 112°; angle of tuberculum sellae, 112°; and sellar-clival angle, 117°. Compared with healthy adults, patients with sellar lesions were more likely to have prominent sellar types (43% vs 25%, p = 0.01), a more acute sellar angle (102° vs 112°, p = 0.03), a more prominent sellar floor (3.8 vs 3.0 mm, p < 0.005), and more acute tuberculum (105° vs 112°, p < 0.01) and sellar-clival (105° vs 117°, p < 0.003) angles. A flat sellar floor was more difficult to identify intraoperatively and more likely to require the use of a chisel or drill to expose (75% vs 25%, p = 0.01). A simple sphenoid sinus configuration (no septa, 1 vertical septum, or 2 symmetric vertical septa) was noted in 71% of studies, and the other 29% showed a complex configuration (2 or more asymmetrical septa, 3 or more septa of any kind, or the presence of a horizontal septum). Intraoperative correlation was more challenging in cases with complex sinus anatomy; the most reliable intraoperative midline markers were the vomer, superior sphenoid rostrum, and bilateral parasellar and clival carotid protuberances.

CONCLUSIONS

Preoperative assessment of neuroimaging studies is critical for characterizing the morphological characteristics of the sphenoid sinus, sellar floor, tuberculum sellae, and clivus. The flat sellar type identified in 11% of people) or a complex sphenoid sinus configuration (in 29% of people) may make intraoperative correlation substantially more challenging. An understanding of the regional anatomy and its variability can improve the safety and accuracy of transsphenoidal and extended endoscopic skull base approaches.

Surgical limits in transnasal approach to opticocarotid region and planum sphenoidale: an anatomic cadaveric study

BACKGROUND

The significance of medial and lateral opticocarotid recesses and the planum sphenoidale region in skull base pathologies for the transsphenoidal-transplanum approach were evaluated.

METHODS

The sphenoid bone block samples were extracted from adult cadavers. Dissections and measurements in the opticocarotid and planum sphenoidale regions were performed in 29 samples using a surgical microscope. For histologic evaluation, oblique sections through the bilateral opticocarotid regions were obtained and examined in eight samples.

RESULTS

Optic, carotid prominences, and medial and lateral opticocarotid recesses can be identified as lateral markers intraoperatively to the extent of the exposure. The lateral opticocarotid recess was observed to be prominent in all samples. In all samples, the groove formed by optic and carotid prominences between the medial and lateral opticocarotid recesses was seen. This groove was designated the inter-recess sulcus. In the transsphenoidal-transplanum approach, the area needed for a reliable bone resection was measured as a mean of 237.32 ± 30.96 mm(2). The mean angle between optic nerves was 115.41 ± 18.39 degrees. The mean anteroposterior length of the planum sphenoidale was 14.84 ± 1.52 mm. In histologic sections, collagenous ligaments between the anterior part of cavernous sinus and the adventitia layer of internal carotid artery were more frequent and regular than the inferior part of optic nerve.

CONCLUSIONS

The lateral opticocarotid recess is a reliable and persistent indicator for extended transsphenoidal surgery. To approach the opticocarotid region near the internal carotid artery and optic nerve, a careful dissection is needed to minimize surgical injuries to the optic nerve and carotid artery. Other factors determining a reliable bone resection are the anteroposterior length of the planum sphenoidale and the distance and width of the angle between optic nerves. Attention should be given to individual anatomic variations of the region when planning and performing transsphenoidal-transplanum surgery.

Intrasellar ultrasound in transsphenoidal surgery: a novel technique

OBJECTIVE

Residual tumor masses are common after transsphenoidal surgery. The risk of a residual mass increases with tumor size and parasellar or suprasellar growth. Transsphenoidal surgery is usually performed without image guidance. We aimed to investigate a new technical solution developed for intraoperative ultrasound imaging during transsphenoidal surgery, with respect to potential clinical use and the ability to identify neuroanatomy and tumor.

METHODS

In 9 patients with pituitary macroadenomas, intrasphenoidal and intrasellar ultrasound was assessed during transsphenoidal operations. Ultrasound B-mode, power-Doppler and color-Doppler images were acquired using a small prototype linear array, side-looking probe. The long probe tip measures only 3 x 4 mm. We present images and discuss the potential of intrasphenoidal and intrasellar and ultrasound in transsphenoidal surgery.

RESULTS

We present 2-dimensional, high-resolution ultrasound images. A small side-looking, high-frequency ultrasound probe can be used to ensure orientation in the midline for the surgical approach to identify important neurovascular structures to be avoided during surgery and for resection control and identification of normal pituitary tissue. The image resolution is far better than what can be achieved with current clinical magnetic resonance imaging technology.

CONCLUSION

We believe that the concept of intrasellar ultrasound can be further developed to become a flexible and useful tool in transsphenoidal surgery.

Emergency endovascular stent graft and coil placement for internal carotid artery injury during transsphenoidal surgery

BACKGROUND

An internal carotid artery (ICA) injury is an uncommon but potentially fatal complication of transsphenoidal surgery.

CASE DESCRIPTION

We report a 61-year-old male patient with a right cavernous ICA injury sustained during transsphenoidal surgery and who underwent endovascular Stent graft placement. The ICA trapping was not indicated because of the absence of the left A1 on preoperative magnetic resonance angiography. During Stent graft placement, the ICA wall could not be completely fit with a stent due to its stiff nature and the carotid curve. The gap between the stent and the ICA wall was filled using a coiling procedure on the first postoperative day.

CONCLUSIONS

Endovascular Stent graft placement for posttranssphenoidal carotid artery injury is a useful technical adjunct to the management strategy and has the potential to minimize the risk of having to sacrifice the ICA. In cases of incomplete reconstruction of the Stent graft placement due to its stiff nature and the carotid curve, an additional coiling procedure could be helpful to obliterate the gap between the stent and the ICA wall. To avoid carotid injury during transsphenoidal surgery, careful preoperative evaluation of vascular structures and meticulous surgical technique are necessary.

Safety and efficacy of the direct endonasal transsphenoidal approach for challenging sellar tumors

INTRODUCTION

The direct endonasal approach to pituitary microadenomas is relatively atraumatic, rapid, and carries a lower complication rate than the sublabial approach. Large macroadenomas (3-4 cm) can still be addressed with this simple, unmodified direct endonasal approach. We present our experience with this unique and challenging patient population.

METHODS

About 64 consecutive patients with large (3-4 cm) pituitary adenomas and craniopharyngiomas were treated by the senior author (SK) using the direct endonasal approach from May 2001 to July 2004. The hospital course, endocrinological function, radiographic imaging, and outpatient follow-up were retrospectively reviewed for each patient.

RESULTS

The mean volume of these lesions was 31.5 cm(3) (range, 10.3-168 cm(3)). Tumor pathologies included 2 craniopharyngiomas, 16 functional, and 46 nonfunctional pituitary adenomas. Suprasellar extension of tumor was evident in all patients and 10 had cavernous sinus invasion. Gross total resection was achieved in 30 patients, near-gross total in 6 patients, and subtotal resection in 26 patients. Eight patients (12.5%) demonstrated postoperative complications, with diabetes insipidus for less than 1 year (n = 4) being the most common. There was no incidence of CSF leak, new panhypopituitarism, or worsened vision. Five patients (7.8%) had tumor residual requiring radiation therapy. Additionally, after a mean clinical follow-up of 24.5 months, 4 patients (6.3%) demonstrated recurrent disease.

CONCLUSIONS

Direct endonasal transsphenoidal surgery enables safe and effective resection of large sellar masses while maintaining a favorable morbidity profile.

Endoscopic endonasal transsphenoidal surgery. Before scrubbing in: tips and tricks

BACKGROUND

The interest in endoscopic endonasal transsphenoidal surgery for the treatment of sellar and perisellar lesions is growing as a consequence of the results achieved in the past 10 years and of the interest by patients, endocrinologists, and neurosurgeons. Furthermore, the special ability of the endoscope to offer a wider and detailed view of anatomic structures is a major advantage that increases the attention of neurosurgeons who seek less invasive procedures and better results. Most neurosurgeons performing transsphenoidal surgery, however, are not used to endoscopy, and changing from microsurgical to endoscopic technique can be difficult and even discouraging, often because of difficulties in the initial phase of the procedure.

TECHNIQUE

With the purpose of helping minimize some of the difficulties, we describe herein useful tips and tricks that mainly concern familiarization with the endoscopic equipment, details of the transsphenoidal anatomy, and endoscopic skills. We stress the steps and details that we judge most important.

CONCLUSION

We believe that by following these recommendations neurosurgeons can overcome, or even avoid, the difficulties frequently encountered transsphenoidal surgery, allowing them to safely and efficiently perform endonasal transsphenoidal endoscopic procedures.