Minimally Invasive Skull Base Surgery

Download Minimally Invasive Skull Base Surgery PDF Online Free

Author :
Publisher : Nova Science Publishers
ISBN 13 : 9781628085679
Total Pages : 0 pages
Book Rating : 4.0/5 (856 download)

DOWNLOAD NOW!


Book Synopsis Minimally Invasive Skull Base Surgery by : Moncef Berhouma

Download or read book Minimally Invasive Skull Base Surgery written by Moncef Berhouma and published by Nova Science Publishers. This book was released on 2013-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Classically defined as the art of curing by the hand, hand intended as the organ of the possible, and positive certitude according to Paul Valery, surgery is shifting toward a scientific discipline with a very high technological valence. Neurosurgery in general, and skull base surgery in particular do not stave off this natural evolution. Obviously, technological advances have driven the tremendous progresses in both diagnosis (CT scan, MRI, angiography ) and therapeutic fields (ultrasonic aspiration, radiosurgery). This technological aspect should not hide the humanistic remnant of the modern neurosurgeon, who should propose the less invasive technique in his possession to treat most efficiently his patient, keeping in mind the quality of life above all. The compromise between the invasiveness of the surgical approach to the skull base and the main goal of the surgery has shed light on the recent concept of minimally invasive skull base surgery.This concept has been conspicuously initiated by Axel Perneczky in the late 1980s under the descriptive keyhole neurosurgery, especially through the renowned eyebrow supra-orbital mini-craniotomy and the implementation of endoscope-assisted microneurosurgery. A decade after, Jho and others introduced the endoscopic endonasal approaches to the skull base, with a perpetual development and an exponential rhythm of scientific publications. This recent paradigm shift toward a minimal approach-related iatrogeny coupled with a maximally efficient surgical target is not so clear cut, as pioneering neurosurgeons such as Cushing, Dandy or Dott among others already adopted this philosophy of work, limited by the technology available at that time that did not permit their minimally invasive expectations. This has been possible only with the progresses made in the fields of imaging, surgical instrumentation, illumination technologies (microscope and endoscope), radiosurgery, and neuroanesthesia.

Endoscopic Approaches to the Skull Base

Download Endoscopic Approaches to the Skull Base PDF Online Free

Author :
Publisher : Karger Medical and Scientific Publishers
ISBN 13 : 3805592108
Total Pages : 246 pages
Book Rating : 4.8/5 (55 download)

DOWNLOAD NOW!


Book Synopsis Endoscopic Approaches to the Skull Base by : Amin B. Kassam

Download or read book Endoscopic Approaches to the Skull Base written by Amin B. Kassam and published by Karger Medical and Scientific Publishers. This book was released on 2012 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews the role of endoscopic endonasal techniques During the last decade the endoscopic endonasal approach (EEA) to the skull base has become a very powerful method to add to the array of neurosurgical technologies. This volume provides a broad overview of the role of transnasal approaches in a wide spectrum of skull base diseases. It starts with a historical perspective of the evolution from the microscope to the endoscope in endonasal surgery and then explores in depth the principles and techniques of the various methods. Discussed are topics based on anatomical boundaries: pituitary fossa to the suprasellar space to the cavernous sinus, clivus and the anterior cranial fossa. Access to the infratemporal and posterior fossae via both the endoscopic endonasal and the retrosigmoid approaches are reviewed. In addition, the critical topic of reconstruction following 'minimally invasive' skull base surgery and finally the learning curve and complications associated with the applications of these new and exciting approaches are discussed. This volume will provide the latest knowledge to help neurosurgeons, otolaryngologists, head and neck surgeons as well as craniofacial surgeons understand the applications and practice of this important technique.

Master Techniques in Otolaryngology - Head and Neck Surgery: Skull Base Surgery

Download Master Techniques in Otolaryngology - Head and Neck Surgery: Skull Base Surgery PDF Online Free

Author :
Publisher : Lippincott Williams & Wilkins
ISBN 13 : 1469888637
Total Pages : 1054 pages
Book Rating : 4.4/5 (698 download)

DOWNLOAD NOW!


Book Synopsis Master Techniques in Otolaryngology - Head and Neck Surgery: Skull Base Surgery by : Carl Snyderman

Download or read book Master Techniques in Otolaryngology - Head and Neck Surgery: Skull Base Surgery written by Carl Snyderman and published by Lippincott Williams & Wilkins. This book was released on 2014-09-29 with total page 1054 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new volume in the MTOS - Head and Neck Surgery Series edited by Eugene Myers, MD presents both the common and advanced procedures in skull base surgery and appeals to both the specialist and the generalist. It covers over 45 procedures and describes both open and minimally invasive approaches to the skull base. Key Features: Authors are world renowned experts in the field Comprehensive coverage of open and minimally invasive techniques Edited by pioneers and leaders in the development of the endoscopic endonasal approach Each chapter follows a tightly designed format with a focus on “how to do it” Includes step-by-step instructions for each procedure Each technique is extensively supplemented with over 1500 color intraoperative photographs and line drawings

Rhinology and Anterior Skull Base Surgery

Download Rhinology and Anterior Skull Base Surgery PDF Online Free

Author :
Publisher : Springer Nature
ISBN 13 : 3030668657
Total Pages : 382 pages
Book Rating : 4.0/5 (36 download)

DOWNLOAD NOW!


Book Synopsis Rhinology and Anterior Skull Base Surgery by : Marios Stavrakas

Download or read book Rhinology and Anterior Skull Base Surgery written by Marios Stavrakas and published by Springer Nature. This book was released on 2021-07-26 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a selection of pertinent patient case-presentations in the field of rhinology, anterior skull base and facial plastics surgery. It further explores the evidence-based management of simple to complex clinical presentations. Each chapter start with the diagnosis and progresses from medical or surgical treatment to the post-operative follow up of the presented clinical condition. The various case reports are concise; however, sufficiently comprehensive and cover conditions from emergencies in adult and paediatric rhinology, to elective care, sino-nasal and anterior skull base neoplasms systemic diseases affecting the nose and paranasal sinuses, and underpinned by illustrations, imaging, and intra-operative photographs to emphasize the clinical approach. Rhinology and Anterior Skull Base Surgery - A Case-based Approach is a highly informative and carefully presented book, providing insights for exam candidates, trainees, general practitioners, rhinologists and otolaryngologists with an interest in anterior skull base, facial plastics and rhinology.

Cerebrovascular surgery

Download Cerebrovascular surgery PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (632 download)

DOWNLOAD NOW!


Book Synopsis Cerebrovascular surgery by :

Download or read book Cerebrovascular surgery written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Vascular Challenges in Skull Base Surgery

Download Vascular Challenges in Skull Base Surgery PDF Online Free

Author :
Publisher : Thieme
ISBN 13 : 1638536465
Total Pages : 569 pages
Book Rating : 4.6/5 (385 download)

DOWNLOAD NOW!


Book Synopsis Vascular Challenges in Skull Base Surgery by : Paul A. Gardner

Download or read book Vascular Challenges in Skull Base Surgery written by Paul A. Gardner and published by Thieme. This book was released on 2021-11-17 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: The essential multidisciplinary guide for the prevention and management of vascular injury from master skull base surgeons Vascular injury is the most significant source of morbidity or mortality during skull base surgery, regardless of the surgical approach. While skull base approaches always placed arteries and veins at risk, newer endoscopic endonasal approaches have introduced new challenges for the prevention and management of vascular injury. Greater anatomic knowledge, additional surgical options, improved instrumentation, advances in interventional neuroradiology, and enhanced training all contribute to successful outcomes. Vascular Challenges in Skull Base Surgery by renowned skull base experts Paul Gardner, Carl Snyderman, Brian Jankowitz, and distinguished contributors, fills a gap in the literature, with invaluable guidance on managing rare but potentially catastrophic surgical complications. The full range of surgical approaches to the anterior, middle, and posterior cranial fossae are covered in 22 chapters. Diverse topics encompass open and endoscopic endonasal surgical approaches, endovascular techniques including balloon test occlusion and embolization, and standard and alternative bypass procedures. The last three chapters discuss venous considerations, neurophysiologic monitoring, and the role of training and simulation in vascular injury prevention. Key learning points, illustrated discussion of relevant anatomy, and tips and tricks are targeted at helping skull base surgeons leverage practical strategies to improve patient outcomes. Key Highlights An impressive group of expert, highly-experienced surgeons share firsthand knowledge Insightful analyses of root causes and clinical pearls provide indispensable prevention tactics High-quality images and videos enhance visual understanding of surgical anatomy and techniques Trainees and practicing skull base surgeons will greatly benefit from the collective knowledge and evidence-based injury avoidance strategies shared by authors who have learned to master the art of skull base surgery.

Cranial, Craniofacial and Skull Base Surgery

Download Cranial, Craniofacial and Skull Base Surgery PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 8847011671
Total Pages : 352 pages
Book Rating : 4.8/5 (47 download)

DOWNLOAD NOW!


Book Synopsis Cranial, Craniofacial and Skull Base Surgery by : Paolo Cappabianca

Download or read book Cranial, Craniofacial and Skull Base Surgery written by Paolo Cappabianca and published by Springer Science & Business Media. This book was released on 2010-11-01 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fruits of Reinvention Surgery related to the human head, its compartment and contents has been reinvented over the past 40 years. A number of instruments, most notably the sophisticated medical imaging device and the operating microscope, have principally fueled this evolution. Along the way, endoscopy and sophisticated navigation capabilities have added to the realization of a unique comprehension of normal and abnormal microanatomy permitting corridors and manipu- tions that allow novel strategies for surgery in these highly vital functional areas. Cappabianca, Califano and Iaconetta have created a detailed and fully modern review of methods and strategies related to complex surgery and therapies associated with this robust reinvention. Technical innovations abound! Distinguished practitioners of these unique developments in the history of surgical - terprise present these amazing technical exercises. The catalog of these approaches, inst- mentation, techniques, strategies and manipulations is inspiring and stands as a testimony to the remarkable progress that we have witnessed in recent decades. The presentation in truly “modern” and represents in many aspects pinnacles of operative achievement. We must ask ourselves, what will be next? Los Angeles, November 2009 Michael L.J. Apuzzo, M.D., Ph.D (hon) Preface We belong to a lucky and happy generation, living during a period of many dramatic, if not revolutionary, technical and technological innovations, such as the digital era, which have changed and improved our routine surgical practice, together with the quality and quantity of life of our patients.

Neuroendoscopy

Download Neuroendoscopy PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 3642390854
Total Pages : 232 pages
Book Rating : 4.6/5 (423 download)

DOWNLOAD NOW!


Book Synopsis Neuroendoscopy by : Spyros Sgouros

Download or read book Neuroendoscopy written by Spyros Sgouros and published by Springer Science & Business Media. This book was released on 2013-11-22 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a result of technological improvements, neuroendoscopy is now used in the treatment of many more patients, enabling the performance of previously unavailable operations with low complication rates and rapid patient recovery. This book presents the distilled experience of world experts in this evolving field. Current applications in a wide variety of settings are explained in detail and likely future developments are identified. In addition, the available neuroendoscopic instruments are reviewed and the results of international trials and collaborative studies, presented. This book will fully acquaint the reader with the breadth and depth of available neuroendoscopy techniques and their impressive therapeutic potential. It should serve as the reference book on neuroendoscopy for the next 10 years.

Becoming Dr. Q

Download Becoming Dr. Q PDF Online Free

Author :
Publisher : Univ of California Press
ISBN 13 : 0520949609
Total Pages : 328 pages
Book Rating : 4.5/5 (29 download)

DOWNLOAD NOW!


Book Synopsis Becoming Dr. Q by : Alfredo Quiñones-Hinojosa

Download or read book Becoming Dr. Q written by Alfredo Quiñones-Hinojosa and published by Univ of California Press. This book was released on 2011-10-01 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today he is known as Dr. Q, an internationally renowned neurosurgeon and neuroscientist who leads cutting-edge research to cure brain cancer. But not too long ago, he was Freddy, a nineteen-year-old undocumented migrant worker toiling in the tomato fields of central California. In this gripping memoir, Alfredo Quiñones-Hinojosa tells his amazing life story—from his impoverished childhood in the tiny village of Palaco, Mexico, to his harrowing border crossing and his transformation from illegal immigrant to American citizen and gifted student at the University of California at Berkeley and at Harvard Medical School. Packed with adventure and adversity—including a few terrifying brushes with death—Becoming Dr. Q is a testament to persistence, hard work, the power of hope and imagination, and the pursuit of excellence. It’s also a story about the importance of family, of mentors, and of giving people a chance.

Endoscopic Surgery of the Orbit E-Book

Download Endoscopic Surgery of the Orbit E-Book PDF Online Free

Author :
Publisher : Elsevier Health Sciences
ISBN 13 : 0323613306
Total Pages : 323 pages
Book Rating : 4.3/5 (236 download)

DOWNLOAD NOW!


Book Synopsis Endoscopic Surgery of the Orbit E-Book by : Raj Sindwani

Download or read book Endoscopic Surgery of the Orbit E-Book written by Raj Sindwani and published by Elsevier Health Sciences. This book was released on 2020-05-24 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Endoscopic orbital procedures are at the forefront of today's multidisciplinary patient care and team approach to problem-solving. Endoscopic Surgery of the Orbit offers state-of-the-art, expert guidance on minimally invasive orbit techniques that promise a more streamlined approach to comprehensive patient care, improved patient satisfaction, and superior outcomes. This unique resource reflects the contemporary, unparalleled partnership between otolaryngology, neurosurgery, and ophthalmology that often also includes a cohesive team of clinicians from many other specialties. - Provides expert perspectives from thought leaders in various specialties, including otolaryngologists, ophthalmologists, neurosurgeons, endocrinologists, medical and radiation oncologists, radiologists, and pathologists. - Details the two-surgeon, multi-handed surgical techniques that have revolutionized the management of complex pathologies involving the orbit and skull base. - Covers the full breadth of endoscopic orbital procedures—from advanced intraconal tumor removal and intracranial techniques involving the optic nerve and optic chiasm to more routine endoscopic procedures such as orbital decompressions, E-DCR, fracture repair, and subperiosteal abscess drainage. - Reviews key topics such as neuromonitoring in orbital and skull base surgery, endoscopic surgery of the intraconal space for tumor resection, Transorbital NeuroEnodscopic Surgery (TONES), and reconstruction of the orbit. - Includes tips and pearls on safe and effective procedures as well as novel approaches and innovations in the equipment used to perform these popular procedures. - Provides superb visual reinforcement with more than 400 high-definition images of anatomy, imaging, and surgical techniques, as well as procedural videos.

Endoscopic Skull Base Surgery

Download Endoscopic Skull Base Surgery PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1597453404
Total Pages : 197 pages
Book Rating : 4.5/5 (974 download)

DOWNLOAD NOW!


Book Synopsis Endoscopic Skull Base Surgery by : Hrayr K. Shahinian

Download or read book Endoscopic Skull Base Surgery written by Hrayr K. Shahinian and published by Springer Science & Business Media. This book was released on 2008-04-26 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: To date, more than three thousand brain and skull base tumors, along with various vascular problems, have been treated by using advanced, fully endoscopic, minimally invasive surgical techniques. In this book, Dr. Hrayr K. Shahinian, director of the Skull Base Institute, compiles these techniques. The book is highly specific and amply illustrated. The step-by-step operating room procedures provide a definitive guide to the difficult yet essential art of skull base surgery.

Neuroendoscopic Surgery

Download Neuroendoscopic Surgery PDF Online Free

Author :
Publisher : Thieme
ISBN 13 : 1626231621
Total Pages : 420 pages
Book Rating : 4.6/5 (262 download)

DOWNLOAD NOW!


Book Synopsis Neuroendoscopic Surgery by : Jaime Torres-Corzo

Download or read book Neuroendoscopic Surgery written by Jaime Torres-Corzo and published by Thieme. This book was released on 2019-04-04 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neuroendoscopy: State-of-the-art, global subspecialty encompassed in multimedia volume Honorable mention from the 2017 PROSE Awards HONORABLE MENTION for Textbook/Clinical Medicine! The development and refinement of neuroendoscopy has been driven by the persistent desire of neurosurgeons to advance the field and offer less invasive, more efficacious options to patients. This remarkable multimedia book reflects the technological advances achieved in the last two decades in fiber optics, cold light, cameras, and endoscopic instrumentation. Written by an impressive Who's Who of international neurosurgeons, the outstanding text and videos reflect global contributions to neuroendoscopy. Current indications for intracranial and intraventricular endoscopy are described in depth, through detailed chapters, stellar videos, professional animations, and exquisite illustrations. The authors share their clinical expertise on procedures ranging from endoscopic third ventriculostomy to transventricular approach of the fourth ventricle. Cover to cover, this book details the differences, alternatives, advantages, and limitations of the flexible neuroendoscope. This hands-on learning tool will enable neurosurgeons to perform endoscopy of the ventricles and basal cisterns for exploratory purposes and conditions such as hydrocephalus, congenital aqueductal stenosis, tumors, hypothalamic hamartoma, arachnoid cysts, and neurocysticercosis. Additional topics include endoscopic-assisted microvascular decompression and aneurysm surgery, fluorescence, complications, anesthesia, utilization in developing countries, and future trends. Key Features: Comprehensive multimedia reference with online access to 70 superb videos and animations More than 300 meticulously drawn illustrations Beautifully illustrated anatomical chapters that facilitate in-depth understanding of endoscopic anatomy An entire chapter devoted to flexible neuroendoscopy Indications, preoperative preparation, procedure description, intraoperative complications and their management ("risk and rescue: techniques), expert pearls, postoperative management, and outcomes This volume is a must-have resource for neurosurgery and neurology residents, neurosurgeons, pediatric neurosurgeons, and all physicians involved in the care of patients with intracranial and intraventricular disease.

Minimally Invasive Neurosurgery

Download Minimally Invasive Neurosurgery PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1588291472
Total Pages : 439 pages
Book Rating : 4.5/5 (882 download)

DOWNLOAD NOW!


Book Synopsis Minimally Invasive Neurosurgery by : Mark R. Proctor

Download or read book Minimally Invasive Neurosurgery written by Mark R. Proctor and published by Springer Science & Business Media. This book was released on 2005-04-14 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recognized clinical leaders in neurosurgery and neuroradiology review the cutting-edge techniques and technologies now available and describe how minimally invasive techniques have influenced their subspecialties. On the radiology side, the authors explain the latest developments in magnetic resonance spectroscopy, functional imaging, and brain mapping, with emphasis on the application of image navigation directly in the operating room, using both preoperative and intraoperative systems. On the surgical side, some of the world's leading surgeons in pediatric neurosurgery, cerebrovascular surgery, neurosurgical oncology, spinal and peripheral nerve surgery, and trauma surgery detail how they use the powerful new minimally invasive techniques in the own practices. Among the novel approaches discussed are radiofrequency, radiosurgery, thermal therapy, and minimally invasive techniques that allow "molecular neurosurgery" via gene and viral vectors and local delivery systems.

Keyhole Approaches in Neurosurgery

Download Keyhole Approaches in Neurosurgery PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 321169501X
Total Pages : 295 pages
Book Rating : 4.2/5 (116 download)

DOWNLOAD NOW!


Book Synopsis Keyhole Approaches in Neurosurgery by : Axel Perneczky

Download or read book Keyhole Approaches in Neurosurgery written by Axel Perneczky and published by Springer Science & Business Media. This book was released on 2009-12-18 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technological progress in neurosurgery - preoperative investigation of the exact anatomy of the patient, detailed planning of the procedure, and use of endoscopes and videosurgery – have made approaches for intracranial microsurgical procedures smaller compared to historically standard neurosurgical approaches. Building on the previous works "Endoscopic Anatomy for Neurosurgery" and "Keyhole Concept in Neurosurgery," this book offers a systematic overview of keyhole approaches in the daily work of a neurosurgeon. The approaches, strategies, indications and technical details described here are complemented by anatomical pictures, schemes, and artists’ illustrations, and analyzed with regard to geometric boundaries and the topography of the target structures.

Anterior Skull Base Tumors

Download Anterior Skull Base Tumors PDF Online Free

Author :
Publisher : Karger Medical and Scientific Publishers
ISBN 13 : 3318066702
Total Pages : 266 pages
Book Rating : 4.3/5 (18 download)

DOWNLOAD NOW!


Book Synopsis Anterior Skull Base Tumors by : P. Nicolai

Download or read book Anterior Skull Base Tumors written by P. Nicolai and published by Karger Medical and Scientific Publishers. This book was released on 2020-07-30 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, interest in the management of anterior skull base tumors has been fostered by the introduction and subsequent rapid expansion of indications of transnasal endoscopic techniques. In parallel, extraordinary progress has been made in all the other disciplines which are involved in the complex process of managing anterior skull base tumors, leading to substantial improvements in diagnosis and treatment. The anterior skull base can be involved in a large variety of tumors of a varying nature and histology, which in the majority of cases originate from adjacent anatomic sites. In fact, primary lesions of the anterior skull base mainly include osteoma and other tumors originating from bone and cartilage. Tumors involving the anterior skull base have their origin prevalently in the sinonasal tract, but lesions developing on the intracranial site, such as meningiomas, may also extend caudally to encroach upon this area. All these lesions are rare, which means that the pertinent literature does not include prospective studies or treatment guidelines based on a high level of evidence. In view of the extreme histological variability of lesions involving the anterior skull base, much emphasis has been placed on addressing the different nuances of treatment in relation to histology, especially for malignant tumors. The chapters focusing on surgery provide divergent views on selection criteria for a specific surgical technique, which is the aim of this publication.

Fundamentals of Neuroanesthesia

Download Fundamentals of Neuroanesthesia PDF Online Free

Author :
Publisher : Oxford University Press
ISBN 13 : 0199755981
Total Pages : 385 pages
Book Rating : 4.1/5 (997 download)

DOWNLOAD NOW!


Book Synopsis Fundamentals of Neuroanesthesia by : Keith J. Ruskin

Download or read book Fundamentals of Neuroanesthesia written by Keith J. Ruskin and published by Oxford University Press. This book was released on 2013-10 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Neuroanesthesia is a comprehensive guide to neuroanesthesia which focuses neurophysiology, neuroanatomy, and neurosurgical procedures, and then offers practical approaches to the practice of neurosurgical anesthesia.

Textbook of Stereotactic and Functional Neurosurgery

Download Textbook of Stereotactic and Functional Neurosurgery PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 3540699597
Total Pages : 3247 pages
Book Rating : 4.5/5 (46 download)

DOWNLOAD NOW!


Book Synopsis Textbook of Stereotactic and Functional Neurosurgery by : Andres M. Lozano

Download or read book Textbook of Stereotactic and Functional Neurosurgery written by Andres M. Lozano and published by Springer Science & Business Media. This book was released on 2009-06-22 with total page 3247 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers stereotactic principles as well as functional stereotaxis, covering the history and uses of the techniques, treatments for specific conditions, and future developments. Includes a DVD demonstrating surgical procedures.