Development of a Cadaveric Multiport Model of Posterior Circulation Aneurysm Clipping for Neurosurgery and Otolaryngology Residents

Published: September 03, 2021

doi:

Haley E. Gillham, Brandon Lucke-Wold, Aclan Dogan, Justin Cetas, William E. Cameron, Jeremy N. Ciporen

¹Oregon Health & Science University, ²West Virginia University School of Medicine

Summary

A model protocol to train neurosurgery and otolaryngology resident learners on endoscopic transclival clipping of posterior circulation aneurysms is described. Two endoscopic approaches to access the silicone-injected or perfused posterior circulation of cadaveric heads are established for training. Learners are tasked with clipping of posterior circulation based on clinical scenarios.

Abstract

Posterior circulation aneurysms are difficult to treat with the current methods of coiling and clipping. To address limitations in training, we developed a cadaveric model to train learners on endoscopic clipping of posterior circulation aneurysms. An endoscopic transclival approach (ETA) and a transorbital precaruncular approach (TOPA) to successfully access and clip aneurysms of the posterior circulation are described. The model has flexibility in that a colored silicone compound can be injected into the cadaveric vessels for the purpose of training learners on vascular anatomy. The other option is that the model could be connected to a vascular perfusion pump allowing real-time appreciation of a pulsatile or ruptured aneurysm. This cadaveric model is the first of its kind for training of endoscopic clipping of posterior circulation aneurysms. Learners will develop proficiency in endoscopic skills, appropriate dissection, and appreciation for relative anatomy while developing an algorithm that can be employed in a real operative arena. Going forward, various clinical scenarios can be developed to enhance the realism, allow learners from different specialties to work together, and emphasize the importance of teamwork and effective communication.

Introduction

Treatment of posterior circulation aneurysms presents unique challenges and has higher complication rates compared to other cerebral aneurysms¹. Transcranial clipping of posterior circulation aneurysms is technically challenging, with high complication rates and morbidity². Endovascular coiling and endoscopic endonasal surgery are safe alternatives, as they reduce complication rates and limit traction on the cerebrum³. Endovascular coiling has been shown to have benefits over open skull base approaches, and most centers now use an endovascular approach to treat cerebral aneurysms⁴. However, many posterior circulation aneurysms are not amenable to coiling due to the location, vessel tortuosity, and vessel size². Recent studies have shown the feasibility of using endoscopic approaches for the clipping of posterior circulation aneurysms⁵^,⁶^,⁷^,⁸.

Although endoscopic endonasal surgery has demonstrated benefits over more invasive procedures, several studies document a learning curve associated with the use of endoscopic equipment⁹^,¹⁰^,¹¹. It is this learning curve and lack of surgeon training and experience that limit the use of this safe and beneficial treatment option³. As endoscopic clipping for aneurysms is revealing itself to be a feasible and a safe treatment course, neurosurgery and otolaryngology residents will need to develop these surgical skill sets during their training. This need for technical skill combined with a steep learning curve necessitates the development of realistic training models, as several repetitions are needed to reduce operative room time and complication rate in endoscopic endonasal surgery⁹^,¹¹. In a human placental model of cerebral aneurysm clipping, Belykh et al. have demonstrated improvement in the use of aneurysm clip applicators in learners after simulation¹². Similarly, training with 3-dimensional printed models has been shown to improve learner technical skills in aneurysm clipping¹³. As with any training model, cost-effectiveness and reproducibility are leading objectives for wider accessibility. We have previously demonstrated the utility of an ETA and a TOPA in a cadaver model of posterior circulation aneurysm clipping, with approach access and visualization affected by clip location¹⁴. TOPA can be used in conjunction with endoscopic endonasal approaches, and has previously demonstrated shorter working distances, improved visualization, and angles resulting in increased access to structures⁴^,¹⁴. The TOPA procedure is a new approach for clip ligation of aneurysms, and its applicability can be further explored via simulation for access to both tumors and aneurysms. In this protocol, we present the steps for development of a realistic, cost-effective, reproducible posterior circulation aneurysm-clipping model using ETA and TOPA as options to train neurosurgery learners. An advantage of our model is learner's exposure to authentic physical anatomy, with the option to incorporate realistic dynamic bleeding in the training of aneurysm clipping. This model can be set up with a static (silicone compound infused) or a dynamic (perfused) anatomy and is applicable to train neurosurgery or otolaryngology learners at various levels of expertise on the anatomy and management of posterior circulation aneurysms.

Protocol

In the development of this model, three cadaveric heads were obtained through the Oregon Health & Science University Body Donation Program and handled per the Code of Ethics approved by the Oregon Health & Science University Institutional Review Board. 1. Head Preparation Obtain fresh cadaveric heads. Secure the head in the sink, resting on a block with the neck facing upwards. Prepare a 5 L 1:100 solution of anticoagulant citrate dextrose and warm water. Use the …

Representative Results

This model presents learners with multiple clinically-relevant sites for posterior circulation clipping, with either static (silicone compound-injected) or dynamic (perfused) options for training. Once dissection is complete, the investigators may use ETA and TOPA to provide learners with improved visualization of the posterior circulation14. Overview of ETA and TOPA are illustrated in Figure 1. For success of the model, investigators …

Discussion

Posterior circulation aneurysms have been historically hard to clip or coil, especially those originating off the SCA and AICA. Several techniques have been tried, such as endovascular pipeline embolization devices, microsurgical skull base approaches, and the supraorbital keyhole approach for clip application¹⁵^,¹⁶^,¹⁷. While these techniques are successful in some cases, the widespread applicability is limited due to stark diffe…

Disclosures

The authors have nothing to disclose.

Acknowledgements

The authors have no acknowledgements.

Materials

Anticoagulant citrate dextrose	Pierce Laboratories	117037
Embalming solution	Chemisphere
10% Formalin fixative	Chemisphere	B2915DR55
Red Microfil solution	Flow Tech	MV-130	Silicone compound
Arterial cannula clamp
5 mm Arterial cannula	Instrument Design & Mfg. Co.	ART187-2-CT	Used for jugular vein and carotid artery cannulation
3 mm Arterial cannula	Instrument Design & Mfg. Co.		Used for vertebral artery cannulation
Curved hemostat	Aesculap	BH139R
Zero-degree endoscope (4 mm diameter, 18 cm length)	Karl Storz	H3-Z TH100
30-degree endoscope (4 mm diameter, 18 cm length)	Karl Storz
Suction – 7 and 10 FR	V. Mueller
11-blade surgical blade	Bard-Parker	371111
Penfield 1	Jarit	285-365
Kerrison rongeur	Aesculap	FM823R, 3mm/180 mm
Pituitary rongeur	Aesculap	FF806R
Transsphenoidal drill	Depuy-Synthes
5 mm coarse diamond burr drill	Depuy-Synthes
Forceps	Jarit	Carb bite I22-500
Iris scissors	Black & Black	B 66110
Perfusion Pump	Belmont Instrument Corporation, Billerica, MA, USA	Belmont Fluid Management System 2000
L-aneurysm clip	Peter Lazic Microsurgical Innovations	45.782
Vessel clip system	Peter Lazic Microsurgical Innovations	45.442
Dural flap clip	Weck	523242

References

Spetzler, R. F., et al. The Barrow Ruptured Aneurysm Trial: 6-year results. J Neurosurg. 123 (3), 609-617 (2015).
Somanna, S., Babu, R. A., Srinivas, D., Narasinga Rao, K. V., Vazhayil, V. Extended endoscopic endonasal transclival clipping of posterior circulation aneurysms–an alternative to the transcranial approach. Acta Neurochir (Wien). 157 (12), 2077-2085 (2015).
Yildirim, A. E., Divanlioglu, D., Karaoglu, D., Cetinalp, N. E., Belen, A. D. Pure Endoscopic Endonasal Clipping of an Incidental Anterior Communicating Artery Aneurysm. J Craniofac Surg. 26 (4), 1378-1381 (2015).
Ciporen, J., Lucke-Wold, B., Dogan, A., Cetas, J. S., Cameron, W. E. Dual Endoscopic Endonasal Transsphenoidal and Precaruncular Transorbital Approaches for Clipping of the Cavernous Carotid Artery: A Cadaveric Simulation. J Neurol Surg B Skull Base. 77 (6), 485-490 (2016).
Szentirmai, O., et al. Endoscopic endonasal clip ligation of cerebral aneurysms: an anatomical feasibility study and future directions. J Neurosurg. 124 (2), 463-468 (2016).
Drazin, D., Zhuang, L., Schievink, W. I., Mamelak, A. N. Expanded endonasal approach for the clipping of a ruptured basilar aneurysm and feeding artery to a cerebellar arteriovenous malformation. J Clin Neurosci. 19 (1), 144-148 (2012).
Ensenat, J., et al. Endoscopic endonasal clipping of a ruptured vertebral-posterior inferior cerebellar artery aneurysm: technical case report. Neurosurgery. 69, 127-128 (2011).
Yoshioka, H., Kinouchi, H. The Roles of Endoscope in Aneurysmal Surgery. Neurol Med Chir (Tokyo). 55 (6), 469-478 (2015).
Shikary, T., et al. Operative Learning Curve after Transition to Endoscopic Transsphenoidal Pituitary Surgery. World Neurosurg. , (2017).
Chi, F., et al. A learning curve of endoscopic transsphenoidal surgery for pituitary adenoma. J Craniofac Surg. 24 (6), 2064-2067 (2013).
Qureshi, T., et al. Learning curve for the transsphenoidal endoscopic endonasal approach to pituitary tumors. Br J Neurosurg. 30 (6), 637-642 (2016).
Belykh, E., et al. Construct Validity of an Aneurysm Clipping Model Using Human Placenta. World Neurosurg. 105, 952-960 (2017).
Mashiko, T., et al. Training in Cerebral Aneurysm Clipping Using Self-Made 3-Dimensional Models. J Surg Educ. 74 (4), 681-689 (2017).
Ciporen, J. N., et al. Multiportal endoscopic approaches to the central skull base: a cadaveric study. World Neurosurg. 73 (6), 705-712 (2010).
Lan, Q., et al. Keyhole approach for clipping intracranial aneurysm: comparison of supraorbital and pterional keyhole approach. World Neurosurg. , (2017).
Rodriguez-Hernandez, A., Walcott, B. P., Birk, H., Lawton, M. T. The Superior Cerebellar Artery Aneurysm: A Posterior Circulation Aneurysm with Favorable Microsurgical Outcomes. Neurosurgery. , (2017).
Mazaris, P., et al. Endovascular Treatment of Complex Distal Posterior Cerebral Artery Aneurysms with the Pipeline Embolization Device. World Neurosurg. , (2017).
Lee, S. H., et al. Surgical Flow Alteration for the Treatment of Intracranial Aneurysms That Are Unclippable, Untrappable, and Uncoilable. J Korean Neurosurg Soc. 58 (6), 518-527 (2015).
Qian, Z. H., Feng, X., Li, Y., Tang, K. Virtual Reality Model of the Three-Dimensional Anatomy of the Cavernous Sinus Based on a Cadaveric Image and Dissection. J Craniofac Surg. , (2017).
Shono, N., et al. Microsurgery Simulator of Cerebral Aneurysm Clipping with Interactive Cerebral Deformation Featuring a Virtual Arachnoid. Oper Neurosurg (Hagerstown). , (2017).
Tomee, S. M., et al. The Consequences of Real Life Practice of Early Abdominal Aortic Aneurysm Repair: A Cost-Benefit Analysis. Eur J Vasc Endovasc Surg. , (2017).
de Oliveira, M. M., et al. Learning brain aneurysm microsurgical skills in a human placenta model: predictive validity. J Neurosurg. , 1-7 (2017).
Valentine, R., Padhye, V., Wormald, P. J. Simulation Training for Vascular Emergencies in Endoscopic Sinus and Skull Base Surgery. Otolaryngol Clin North Am. 49 (3), 877-887 (2016).
Di Somma, A., et al. Extended endoscopic endonasal approaches for cerebral aneurysms: anatomical, virtual reality and morphometric study. Biomed Res Int. 2014, 703792 (2014).
Oyama, K., et al. Endoscopic endonasal cranial base surgery simulation using an artificial cranial base model created by selective laser sintering. Neurosurg Rev. 38 (1), 171-178 (2015).
Jukes, A. K., et al. Stress response and communication in surgeons undergoing training in endoscopic management of major vessel hemorrhage: a mixed methods study. Int Forum Allergy Rhinol. , (2017).