A Novel Method for Angioscopic Imaging and Visualizing the Skull Base Using Complementary Metal Oxide Semiconductor Cameras

Neurosurgery 93:1432–1436, 2023

Complementary metal oxide semiconductor (CMOS) electrode arrays are a novel technology for miniaturized endoscopes; however, its use for neurointervention is yet to be investigated. In this proof-of-concept study, we aimed to demonstrate the feasibility of CMOS endoscopes in a canine model by providing direct visualization of the endothelial surface, deploying stents and coils, and accessing the spinal subdural space and skull base.

METHODS: Using 3 canine models, standard guide catheters were introduced into the internal carotid and vertebral arteries through the transfemoral route using fluoroscopy. A 1.2-mm CMOS camera was delivered through the guide catheter to inspect the endothelium. Next, the camera was introduced alongside standard neuroendovascular devices including coils and stents to provide direct visualization of their deployment within the endothelium during fluoroscopy. One canine was used for skull base and extravascular visualization. A lumbar laminectomy was performed, and the camera was navigated within the spinal subdural space until the posterior circulation intracranial vasculature was visualized.

RESULTS: We successfully visualized the endothelial surface and performed several endovascular procedures such as deployment of coils and stents under direct endovascular, angioscopic vision. We also demonstrated a proof of concept for accessing the skull base and posterior cerebral vasculature using CMOS cameras through the spinal subdural space.

CONCLUSION: This proof-of-concept study demonstrates the feasibility of CMOS camera technology to directly visualize endothelium, perform common neuroendovascular procedures, and access the base of the skull in a canine model.

From white to blue light: evolution of endoscope-assisted intracranial tumor neurosurgery and expansion to intraaxial tumors

J Neurosurg 139:59–64, 2023

Intraoperative use of the endoscope to assist in visualization of intracranial tumor pathology has expanded with increasing surgeon experience and improved instrumentation. The authors aimed to study how advancements in endoscopic technology have affected the evolution of endoscope use, with particular focus on blue light–filter modification allowing for discrimination of fluorescent tumor tissue following 5-ALA administration.

METHODS A retrospective analysis of patients undergoing craniotomy for tumor resection at a single institution between February 2012 and July 2021 was performed. Patients were included if the endoscope was used for diagnostic tumor cavity inspection or therapeutic assistance with tumor resection following standard craniotomy and microsurgical tumor resection, with emphasis on those cases in which blue light endoscopy was used. Medical records were queried for patient demographics, operative reports describing the use of the endoscope and extent of resection, associations with tumor pathology, and postoperative outcomes. Preoperative and postoperative MR images were reviewed for radiographic extent of resection.

RESULTS A total of 52 patients who underwent endoscope-assisted craniotomy for tumor were included. Thirty patients (57.7%) were men and the average age was 52.6 ± 16.1 years. Standard white light endoscopes were used for assistance with tumor resection in 28 cases (53.8%) for tumors primarily located in the ventricular system, parasellar region, and cerebellopontine angle. A blue light endoscope for detection of 5-ALA fluorescence was introduced into our practice in 2014 and subsequently used for assistance with tumor resection in 24 cases (46.2%) (intraaxial: n = 22, extraaxial: n = 2). Beyond the use of the surgical microscope as the primary visualization source, the blue light endoscope was used to directly perform additional tumor resection in 19/21 cases as a result of improved fluorescence detection as compared to the surgical microscope. No complications were associated with the use of the endoscope or with additional resection performed under white or blue light visualization.

CONCLUSIONS Endoscopic assistance to visualize intracranial tumors had previously been limited to white light, assisting mostly in the visualization of extraaxial tumors confined to intraventricular and cisternal compartments. Blue light– equipped endoscopes provide improved versatility and visualization of 5-ALA fluorescing tissue beyond the capability of the surgical microscope, thereby expanding its use into the realm of intraaxial tumor resections.

Minimally invasive image‑guided endoscopic evacuation of intracerebral haemorrhage

Acta Neurochirurgica (2023) 165:1597–1602

Minimally invasive endoscopic hematoma evacuation (MEHE) is an emerging surgical technique for treating spontaneous supratentorial intracerebral haemorrhage (SSICH). Multiple studies, analysing whether the outcome after such a procedure is improved, are still ongoing.

Method We herein present the indications, advantages, and perioperative considerations for the surgical technique of MEHE applied at our institution.

Conclusion MEHE with a view through a transparent brain access device is a valid and safe approach for the surgical evacuation of SSICH.

Utility of the Vidian Canal in Endoscopic Skull Base Surgery: Detailed Anatomy and Relationship to the Internal Carotid Artery

World Neurosurg. (2019) 121:e140-e146

OBJECTIVE: To investigate key anatomic features of the vidian canal that have a critical role in planning and performing endoscopic skull base surgeries.

METHODS: We reviewed skull base computed tomographic images of 640 consecutive subjects. Studies were analyzed in axial, coronal and sagittal planes. –

RESULTS: The mean (SD) length of the vidian canal was 15.4±2.0 mm in female subjects and 16.6±1.7 mm in male subjects, and the difference between genders was statistically significant (P < 0.001). The most common rostral-caudal course of the vidian canal was medial to lateral and was followed by the straight course, tortuous course, and lateral-to-medial course. The frequency of pneumatization pattern from most common to least common was types 0, III, II and I. Of 342 evaluated sides, the vidian canal was located below the level of the anterior genu of petrous ICA in 303 (89%) sides, at same level with the anterior genu of petrous ICA in twenty-five(7%) sides, and above the level of the anterior genu of petrous ICA in fourteen(4.1%) sides.

CONCLUSIONS: A variety of previously undefined features of the vidian canal that can alter the course of surgical procedure were defined. The position of the vidian canal with respect to the petrous internal carotid artery (ICA) was extensively described. From a surgical standpoint, a working room inferior and medial to the vidian canal might not always be a safe approach, because the vidian canal could be located superior to the level of the anterior genu of petrous ICA according to our findings in the present study.

Effectiveness of endoscopic surgery for supratentorial hypertensive intracerebral hemorrhage: a comparison with craniotomy

J Neurosurg 128:553–559, 2018

The goal of this study was to investigate the effectiveness and practicality of endoscopic surgery for treatment of supratentorial hypertensive intracerebral hemorrhage (HICH) compared with traditional craniotomy.

METHODS The authors retrospectively analyzed 151 consecutive patients who were operated on for treatment of supratentorial HICH between January 2009 and June 2014 in the Department of Neurosurgery at Chinese PLA General Hospital. Patients were separated into an endoscopy group (82 cases) and a craniotomy group (69 cases), depending on the surgery they received. The hematoma evacuation rate was calculated using 3D Slicer software to measure the hematoma volume. Comparisons of operative time, intraoperative blood loss, Glasgow Coma Scale score 1 week after surgery, hospitalization time, and modified Rankin Scale score 6 months after surgery were also made between these groups.

RESULTS There was no statistically significant difference in preoperative data between the endoscopy group and the craniotomy group (p > 0.05). The hematoma evacuation rate was 90.5% ± 6.5% in the endoscopy group and 82.3% ± 8.6% in the craniotomy group, which was statistically significant (p < 0.01). The operative time was 1.6 ± 0.7 hours in the endoscopy group and 5.2 ± 1.8 hours in the craniotomy group (p < 0.01). The intraoperative blood loss was 91.4 ± 93.1 ml in the endoscopy group and 605.6 ± 602.3 ml in the craniotomy group (p < 0.01). The 1-week postoperative Glasgow Coma Scale score was 11.5 ± 2.9 in the endoscopy group and 8.3 ± 3.8 in the craniotomy group (p < 0.01). The hospital stay was 11.6 ± 6.9 days in the endoscopy group and 13.2 ± 7.9 days in the craniotomy group (p < 0.05). The mean modified Rankin Scale score 6 months after surgery was 3.2 ± 1.5 in the endoscopy group and 4.1 ± 1.9 in the craniotomy group (p < 0.01). Patients had better recovery in the endoscopy group than in the craniotomy group. Data are expressed as the mean ± SD.

CONCLUSIONS Compared with traditional craniotomy, endoscopic surgery was more effective, less invasive, and may have improved the prognoses of patients with supratentorial HICH. Endoscopic surgery is a promising method for treatment of supratentorial HICH. With the development of endoscope technology, endoscopic evacuation will become more widely used in the clinic. Prospective randomized controlled trials are needed.

 

Microendoscopic laminotomy versus conventional laminoplasty for cervical spondylotic myelopathy: 5-year follow-up study

J Neurosurg Spine 27:403–409, 2017

The goal of this study was to characterize the long-term clinical and radiological results of articular segmental decompression surgery using endoscopy (cervical microendoscopic laminotomy [CMEL]) for cervical spondylotic myelopathy (CSM) and to compare outcomes to conventional expansive laminoplasty (ELAP).

METHODS Consecutive patients with CSM who required surgical treatment were enrolled. All enrolled patients (n = 78) underwent CMEL or ELAP. All patients were followed postoperatively for more than 5 years. The preoperative and 5-year follow-up evaluations included neurological assessment (Japanese Orthopaedic Association [JOA] score), JOA recovery rates, axial neck pain (using a visual analog scale), the SF-36, and cervical sagittal alignment (C2–7 subaxial cervical angle).

RESULTS Sixty-one patients were included for analysis, 31 in the CMEL group and 30 in the ELAP group. The mean preoperative JOA score was 10.1 points in the CMEL group and 10.9 points in the ELAP group (p > 0.05). The JOA recovery rates were similar, 57.6% in the CMEL group and 55.4% in the ELAP group (p > 0.05). The axial neck pain in the CMEL group was significantly lower than that in the ELAP group (p < 0.01). At the 5-year follow-up, cervical alignment was more favorable in the CMEL group, with an average 2.6° gain in lordosis (versus 1.2° loss of lordosis in the ELAP group [p < 0.05]) and lower incidence of postoperative kyphosis.

CONCLUSIONS CMEL is a novel, less invasive technique that allows for multilevel posterior cervical decompression for the treatment of CSM. This 5-year follow-up data demonstrates that after undergoing CMEL, patients have similar neurological outcomes to conventional laminoplasty, with significantly less postoperative axial pain and improved subaxial cervical lordosis when compared with their traditional ELAP counterparts.

Craniotomy for perisellar meningiomas: comparison of simple (appropriate for endoscopic approach) versus complex anatomy and surgical outcomes

J Neurosurg 126:1191–1200, 2017

Microsurgical resection of perisellar meningiomas has remained the gold standard for treatment, with extended endoscopic endonasal surgery emerging as a viable alternative. Historical microsurgical series do not distinguish based on tumor anatomy, but are being used as a comparison against endonasal surgery. In this study, the authors retrospectively reviewed and compared the anatomy of perisellar meningiomas seen at their institution. The tumors were separated into 2 groups based on whether they would be appropriate for endoscopic resection, and the authors compared the surgical outcomes.

METHODS Between 2001 and 2013, 53 patients (73.6% women) with perisellar meningiomas underwent open microsurgical resection at Vancouver General Hospital performed by the senior author (R.A.). These tumors were separated into 2 groups based on their anatomy, and the authors analyzed the resection rates, surgical results, patient quality of life, and complications.

RESULTS Among the 53 patients who presented with perisellar meningiomas, the authors were able to identify 18 lesions with “simple” anatomy suitable for endoscopic resection and 35 lesions with “complex” anatomy suitable for craniotomy resection. The mean age of patients in the study cohort was 57.4 years (range 33–91 years), and most patients presented with visual loss (68.0%) and visual field restriction (64.2%). There were no major differences in patient demographic data between the 2 groups. Patients with simple anatomy had smaller lesions (2.1 vs 3.5 cm; p = 0.004), no optic canal invasion (89% vs 26%; p < 0.0001), minimal vascular encasement (cortical cuff 83% vs 9%; p < 0.0001), and a rounded tumor shape (100% vs 31.8%; p = 0.0001) when compared with those with complex anatomy. The majority of lesions originated from the tuberculum sellae and planum sphenoidale. A greater degree of resection was achieved in the favorable anatomy group (99% vs 87.1%; p < 0.0001). Vision was improved or normalized in 96.6% of patients. Patients in the cohort with complex anatomy had more transient complications; there were no incidents of surgical-site infection, meningitis, or death in this series. One patient who underwent removal of a recurrent lesion experienced a CSF leak that required endoscopic repair. The overall persisting complications rate was higher in the group with complex anatomy (11.1% vs 37.1%; p = 0.0498); overall, 28.3% of patients experienced disabling complications. Patient-perceived quality of life improved in the simple anatomy group following surgery (DSF-36 +16.6 vs -8.4; p = 0.0045).

CONCLUSIONS Extended endoscopic surgery is emerging as a viable alternative to microsurgical resection of perisellar meningiomas. The authors identified 2 patient groups based on tumor anatomy, with distinctly separate surgical outcomes. In the future, patients considered for endoscopic resection should be compared against the surgical group with simple anatomy that includes smaller tumors, no vascular encasement, and limited optic canal invasion.

 

 

Comparison of outcomes between a less experienced surgeon using a fully endoscopic technique and a very experienced surgeon using a microscopic transsphenoidal technique for pituitary adenoma

Intraoperative high-field MRI for transsphenoidal reoperations of nonfunctioning pituitary adenoma

J Neurosurg 124:596–604, 2016

The comparative efficacy of microscopic and fully endoscopic transsphenoidal surgery for pituitary adenomas has not been well studied despite the adoption of fully endoscopic surgery by many pituitary centers. The influence of surgeon experience has also not been examined in this setting. The authors therefore compared the extent of tumor resection (EOR) and the endocrine outcomes of 1 very experienced surgeon performing a microscopic transsphenoidal surgery technique with those of a less experienced surgeon using a fully endoscopic transsphenoidal surgery technique for resection of nonfunctioning pituitary adenomas in a concurrent series of patients.

Methods Post hoc analysis was conducted of a cohort of adult patients prospectively enrolled in a pituitary adenoma quality-of-life study between October 2011 and June 2014. Patients were followed up for 6 months after surgery. Patients were treated either by a less experienced surgeon (100 independent cases) who practices fully endoscopic surgery exclusively or by a very experienced surgeon (1800 independent cases) who practices microscopic surgery exclusively. Patient demographic characteristics, tumor characteristics, hypopituitarism, complications, and length of hospital stay were analyzed. Tumor volumes and EOR were determined by formal volumetric analysis involving manual segmentation of MR images performed before surgery and within 6 months after surgery. Logistic regression analysis was used to determine predictors of EOR.

Results Fifty-five patients underwent fully endoscopic transsphenoidal surgery, and 80 patients underwent fully microscopic transsphenoidal surgery. The baseline characteristics of the 2 treatment groups were well matched. EOR was similar between the endoscopic and microscopic groups, respectively, as estimated by gross-total resection rate (78.2% vs 81.3%, p = 0.67), percentage of tumor resected (99.2% vs 98.7%, p = 0.42), and volume of residual tumor (0.12 cm3 vs 0.20 cm3, p = 0.41). Multivariate modeling suggested that preoperative tumor volume was the most important predictor of EOR (p = 0.001). No difference was found in the development of anterior gland dysfunction (p > 0.14), but there was a higher incidence of permanent posterior gland dysfunction in the microscopic group (p = 0.04). Combined rates of major complications and unplanned readmissions were lower in the endoscopic group (p = 0.02), but individual complications were not significantly different.

Conclusions A less experienced surgeon using a fully endoscopic technique was able to achieve outcomes similar to those of a very experienced surgeon using a microscopic technique in a cohort of patients with nonfunctioning tumors smaller than 60 cm3. The study raises the provocative notion that certain advantages afforded by the fully endoscopic technique may impact the learning curve in pituitary surgery for nonfunctioning adenomas.

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

Morphometric analysis of the medial opticocarotid recess

Acta Neurochir (2016) 158:319–324

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.

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

Neurosurg Focus 32 (6):E7, 2012. DOI: 10.3171/2012.5.FOCUS1255

Extended endoscopic endonasal approaches have allowed for a minimally invasive solution for removal of a variety of ventral skull base lesions, including intradural tumors. Depending on the location of the pathological entity, various types of surgical corridors are used, such as transcribriform, transplanum transtuberculum, transsellar, transclival, and transodontoid approaches. Often, a large skull base dural defect with a high-flow CSF leak is created after endoscopic skull base surgery. Successful reconstruction of the cranial base defect is paramount to separate the intracranial contents from the paranasal sinus contents and to prevent postoperative CSF leakage. The vascularized pedicled nasoseptal flap (PNSF) has become the workhorse for cranial base reconstruction after endoscopic skull base surgery, dramatically reducing the rate of postoperative CSF leakage since its implementation.

In this report, the authors review the surgical technique and describe the operative nuances and lessons learned for successful multilayered PNSF reconstruction of cranial base defects with high-flow CSF leaks created after endoscopic skull base surgery. The authors specifically highlight important surgical pearls that are critical for successful PNSF reconstruction, including target-specific flap design and harvesting, pedicle preservation, preparation of bony defect and graft site to optimize flap adherence, multilayered closure technique, maximization of the reach of the flap, final flap positioning, and proper bolstering and buttressing of the PNSF to prevent flap dehiscence. Using this technique in 93 patients, the authors’ overall postoperative CSF leak rate was 3.2%.

An illustrative intraoperative video demonstrating the reconstruction technique is also presented.

Endoscopic endonasal skull base surgery: analysis of complications in the authors’ initial 800 patients

J Neurosurg 114:1544–1568, 2011. DOI: 10.3171/2010.10.JNS09406

The development of endoscopic endonasal approaches, albeit in the early stages, represents part of the continuous evolution of skull base surgery. During this early period, it is important to determine the safety of these approaches by analyzing surgical complications to identify and eliminate their causes.

Methods. The authors reviewed all perioperative complications associated with endoscopic endonasal skull base surgeries performed between July 1998 and June 2007 at the University of Pittsburgh Medical Center.

Results. This study includes the data for the authors’ first 800 patients, comprising 399 male (49.9%) and 401 female (50.1%) patients with a mean age of 49.21 years (range 3–96 years). Pituitary adenomas (39.1%) and meningiomas (11.8%) were the 2 most common pathologies. A postoperative CSF leak represented the most common complication, occurring in 15.9% of the patients. All patients with a postoperative CSF leak were successfully treated with a lumbar drain and/or another endoscopic approach, except for 1 patient who required a transcranial repair. The incidence of postoperative CSF leaks decreased significantly with the adoption of vascularized tissue for reconstruction of the skull base (< 6%). Transient neurological deficits occurred in 20 patients (2.5%) and permanent neurological deficits in 14 patients (1.8%). Intracranial infection and systemic complications were encountered and successfully treated in 13 (1.6%) and 17 (2.1%) patients, respectively. Seven patients died during the 30-day perioperative period, 6 of systemic illness and 1 of infection (overall mortality 0.9%).

Conclusions. Endoscopic endonasal skull base surgery provides a viable median corridor based on anatomical landmarks and is customized according to the specific pathological process. This corridor should be considered as the sole access or may be combined with traditional approaches. With the incremental acquisition of skills and experience, endoscopic endonasal approaches have an acceptable safety profile in select patients presenting with various skull base pathologies.

Early endoscope-assisted hematoma evacuation in patients with supratentorial intracerebral hemorrhage: case selection, surgical technique, and long-term results

Neurosurg Focus 30 (4):E9, 2011. DOI: 10.3171/2011.2.FOCUS10313

Currently, the effectiveness of minimally invasive evacuation of intracerebral hemorrhage (ICH) utilizing the endoscopic method is uncertain and the technique is considered investigational.

The authors analyzed their experience with this method in terms of case selection, surgical technique, and long-term results.

Methods. The authors performed a retrospective analysis of the clinical and radiographic data obtained in 68 patients treated with endoscope-assisted ICH evacuation. Rebleeding, morbidity, and mortality were recorded as primary end points. Hematoma evacuation rate was calculated by comparing the pre- and postoperative CT scans. Glasgow Coma Scale scores and scores on the extended Glasgow Outcome Scale (GOSE) were recorded at the 6-month postoperative follow-up. The technical aspect of this report explains details of the procedure, the instruments that are used, the methods for hemostasis, and the role of hemostatic agents in the management of intraoperative hemorrhage. The pertinent literature was reviewed and summarized.

Results. All surgeries were performed within 12 hours of ictus, and 84% of the surgeries were performed within 4 hours. The mortality rate was 5.9%, and surgery-related morbidity occurred in 3 cases (4.4%). The hematoma evacuation rate was 93% overall—96% in the putaminal group, 86% in the thalamic group, and 98% in the subcortical group. The rebleeding rate was 1.5%. The mean operative time was 85 minutes, and the average blood loss was 56 ml. The mean GOSE score was 4.9 at 6-month follow-up. The authors acknowledge the limitations of these preliminary results in a small number of patients.

Conclusions. The data suggest that early endoscope-assisted ICH evacuation is safe and effective in the management of supratentorial ICH. The rebleeding, morbidity, and mortality rates are low compared with rates reported in the literature for the traditional craniotomy method. This study also showed that early and complete evacuation of ICH may lead to improved outcomes in selected patients. However, the safety and efficacy of endoscope-assisted ICH evacuation should be further investigated in a large, prospective, randomized trial.