Two-Stage Pulsatile Human Placenta Model for Microvascular Anastomosis Training in Neurosurgery.

OBJECTIVE: The development of microsurgical skills is crucial for neurosurgical education. The human placenta is a promising model for practicing vascular anastomosis due to its similarities with brain vessels. We propose a 2-stage model for training in extracranial-to-intracranial anastomosis using the placenta. METHODS: Initially, we propose practicing anastomosis in 2 adjacent placentas. Once successful, the procedure advances to a more challenging configuration that employs a 3-dimensionally printed skull with a window simulating a pterional craniotomy. It is positioned an intracranial placenta and an extracranial one, and the latter has a prominent vessel exposed toward the side of the craniotomy. Both placentas have one artery and vein cannulated in the umbilical cord, and we present an artificial placental circulation system for microvascular training that regulates pulsation and hydrodynamic pressure while keeping veins engorged with a pressurized bag. To verify anastomosis patency, we utilize sodium fluorescein and iodine contrast. RESULTS: The 2-stage model simulated several aspects of microvascular anastomosis. Our perfusion system allowed for intraoperative adjustments of hydrodynamic pressure and pulsation. Using iodine contrast and fluorescein enabled proper evaluation of anastomosis patency and hydrodynamic features. CONCLUSIONS: Training in the laboratory is essential for developing microsurgical skills. We have presented a model for microvascular anastomosis with artificial circulation and postoperative imaging evaluation, which is highly beneficial for enhancing the learning curve in microvascular procedures.

Transmastoid/Infralabyrinthine Approach to the Jugular Foramen: 2-Dimensional Operative Video.

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE: This approach is intended for tumors centered in the jugular foramen with extensions between intracranial and extracranial spaces, possible spread to the middle ear, and variable bony destruction. 1,2. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Jugular foramen paragangliomas are complex lesions that usually invade and fill related venous structures. They present complex relationships with skull base neurovascular structures as internal carotid artery, lower cranial nerves (CNs), middle ear, and mastoid segment of facial nerve. In this way, it is essential to perform an adequate preoperative vascular study to evaluate sinus patency and the tumor blood supply, besides a computed tomography scan to depict bone erosion. ESSENTIAL STEPS OF THE PROCEDURE: Mastoidectomy through an infralabyrinthine route up to open the lateral border of jugular foramen, allowing exposure from the sigmoid sinus to internal jugular vein. Skeletonization of facial canal without exposure of facial nerve is performed and opening of facial recess to give access to the middle ear in way of a fallopian bridge technique. 2-10. PITFALLS/AVOIDANCE OF COMPLICATIONS: If there is preoperative preservation of lower CN function, it is important to not remove the anteromedial wall of the internal jugular vein and jugular bulb. In addition, facial nerve should be exposed just in case of preoperative facial palsy to decompress or reconstruct the nerve. VARIANTS AND INDICATIONS FOR THEIR USE: Variations are related mainly with temporal bone drilling depending on the extensions of the lesion, its source of blood supply, and preoperative preservation of CN function.Informed consent was obtained from the patient for the procedure and publication of his image.Anatomy images were used with permission from:• Ceccato GHW, Candido DNC, and Borba LAB. Infratemporal fossa approach to the jugular foramen. In: Borba LAB and de Oliveira JG. Microsurgical and Endoscopic Approaches to the Skull Base. Thieme Medical Publishers. 2021.• Ceccato GHW, Candido DNC, de Oliveira JG, and Borba LAB. Microsurgical Anatomy of the Jugular Foramen. In: Borba LAB and de Oliveira JG. Microsurgical and Endoscopic Approaches to the Skull Base. Thieme Medical Publishers. 2021.

Microsurgical Resection of Giant Petroclival Meningioma via the Posterior Petrosal Approach: 2-Dimensional Operative Video.

Petroclival meningiomas are challenging deep-seated lesions related to many critical neurovascular structures of the skull base.1-5 We present the case of a 45-year-old male presenting with a 3-year history of progressive headache associated gradually with multiple cranial nerves deficits and progressive tetraparesis leading to use of a wheelchair (Video 1) Preoperative magnetic resonance imaging demonstrated a mass highly suggestive of a giant left petroclival meningioma. Considering worsening of symptoms and impressive mass effect, microsurgical resection employing the posterior petrosal approach was performed. Mastoidectomy with skeletonization of semicircular canals and a craniotomy approaching both posterior and middle cranial fossae were done. Dural incision at the base of the temporal lobe was communicated to other incision in the presigmoid dura by ligation and sectioning of superior petrosal sinus. Tentorium was cut all the way toward the incisura, with attention to preserve the fifth nerve along its division and fourth nerve in the last cut. After a complete tentorium incision, the presigmoid space enlarged, exposing both supratentorial and infratentorial spaces. The lesion was totally resected employing microsurgical techniques. Postoperative magnetic resonance imaging demonstrated complete tumor resection. The patient experienced improvement of complaints and no new neurologic deficit on follow-up. The posterior petrosal approach gives great exposure and a more lateral angle of attack to the ventral surface of brainstem, allowing in this case to approach the whole tumor attachment. Informed consent was obtained from the patient for the procedure and publication of this operative video. Anatomic images were courtesy of the Rhoton Collection, American Association of Neurological Surgeons/Neurosurgical Research and Education Foundation.