Category Archives: Peripheral Nerve

Update: F wave

wave is the second of two voltage changes observed after electrical stimulation is applied to the skin surface above the distal region of a nerve.

F waves are often used to measure nerve conduction velocity, and are particularly useful for evaluating conduction problems in the proximal region of nerves (i.e., portions of nerves near the spinal cord).

It’s called F wave because it was initially recorded in the foot muscles.

In a typical F wave study, a strong electrical stimulus (supramaximal stimulation) is applied to the skin surface above the distal portion of a nerve so that the impulse travels both distally (towards the muscle fiber) and proximally (back to the motor neurons of the spinal cord). (These directions are also known as orthodromic and antidromic, respectively.) When the orthodromic stimulus reaches the muscle fiber, it elicits a strong M-response indicative of muscle contraction. When the antidromic stimulus reaches the motor neuron cell bodies, a small portion of the motor neurons backfire and orthodromic wave travels back down the nerve towards the muscle. This reflected stimulus evokes small proportion of the muscle fibers causing a small, second CMAP called the F wave.

Because a different population of anterior horn cells is stimulated with each stimulation, each F wave have a slightly different shape, amplitude and latency.

F wave properties include:

amplitude (µV) – F wave height duration (ms) – length of F wave latency (ms) – period between F wave and initial stimulation F wave measurements[edit] Several measurements can be done on the F responses, including minimal and maximal latencies, and F wave persistence.

The minimal F wave latency is typically 25-32 ms in the upper extremities, and 45-56 ms in the lower extremities.

F wave persistence is the number of F waves obtained per the number of stimulations, which is normally 80-100% (or above 50%).


Each skeletal muscle is usually supplied by two or more nerve roots and if one nerve root is affected and the other is spared, the clinically used F wave minimum latency can still be normal 1).


In Guillain Barré syndrome (GBS) with antiganglioside antibodies, isolated absence of F waves is a frequent conduction abnormality especially in the early phase of the disease, and may be caused by axonal dysfunction, such as physiological conduction block or axonal degeneration at the nerve roots 2).


Facial F-wave, blink reflex and facial corticobulbar motor evoked potentials (FCoMEP), are feasible to intra-operatively study changes in excitability of the facial nerve and its nucleus during MVDs. Intra-operative neuromonitoring with the mentioned techniques allows a better understanding of HFS pathophysiology and helps to optimise the MVD 3).


The hypoglossal-facial nerve by “side”-to-side anastomisis with pre-degenerated auto-nerve graft was effective for the treatment of peripheral facial palsy after CPA tumor resection, F wave can be used as one of the objective index for the effect of the operation 4).

1)

Sathya GR, Krishnamurthy N, Veliath S, Arulneyam J, Venkatachalam J. F wave index: A diagnostic tool for peripheral neuropathy. Indian J Med Res. 2017 Mar;145(3):353-357. doi: 10.4103/ijmr.IJMR_1087_14. PubMed PMID: 28749398.
2)

Kuwabara S, Ogawara K, Mizobuchi K, Koga M, Mori M, Hattori T, Yuki N. Isolated absence of F waves and proximal axonal dysfunction in Guillain-Barré syndrome with antiganglioside antibodies. J Neurol Neurosurg Psychiatry. 2000 Feb;68(2):191-5. PubMed PMID: 10644786; PubMed Central PMCID: PMC1736791.
3)

Fernández-Conejero I, Ulkatan S, Sen C, Deletis V. Intra-operative neurophysiology during microvascular decompression for hemifacial spasm. Clin Neurophysiol. 2012 Jan;123(1):78-83. doi: 10.1016/j.clinph.2011.10.007. Epub 2011 Dec 1. Review. PubMed PMID: 22136736.
4)

Tao X, Li P, Wan H, Liu S, Liu Y, Qiao H. [Preliminary study of facial nerve F wave evaluation hypoglossal-facial nerve reconstruction with predegenerated nerve graft for peripheral facial palsy]. Zhonghua Yi Xue Za Zhi. 2015 Jun 2;95(21):1648-50. Chinese. PubMed PMID: 26675791.

Nerve Cases: High Yield Scenarios for Oral and Written Testing

Nerve Cases: High Yield Scenarios for Oral and Written Testing
By Amgad S. Hanna

Nerve Cases: High Yield Scenarios for Oral and Written Testing

List Price: $109.00

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This book addresses the severe knowledge deficit in peripheral nerve amongst neurosurgeons, however this topic represents an integral part of the oral board examination. The book employs a case based approach with the highest-yield scenarios for oral boards, primarily focusing on nerve entrapments, trauma and tumors. Thanks to its question and answer format, the reader is encouraged to think about the cases and questions as if taking the real exam before they check the answers. The work also includes common pitfalls, a section on nerve examinations including video recordings, and a section on important clinical findings that should be diagnosed from the picture. The book not only serves neurosurgeons, but also plastic surgeons, orthopedists, and neurologists.


Product Details

  • Published on: 2016-09-13
  • Original language: English
  • Number of items: 1
  • Dimensions: .0″ h x .0″ w x .0″ l, .0 pounds
  • Binding: Paperback
  • 209 pages

Editorial Reviews

From the Back Cover

This book addresses the severe knowledge deficit in peripheral nerve amongst neurosurgeons, however this topic represents an integral part of the oral board examination. The book employs a case based approach with the highest-yield scenarios for oral boards, primarily focusing on nerve entrapments, trauma and tumors. Thanks to its question and answer format, the reader is encouraged to think about the cases and questions as if taking the real exam before they check the answers. The work also includes common pitfalls, a section on nerve examinations including video recordings, and a section on important clinical findings that should be diagnosed from the picture. The book not only serves neurosurgeons, but also plastic surgeons, orthopedists, and neurologists.

About the Author

Amgad Hanna is an assistant professor in the Department of Neurological Surgery at the University of Wisconsin. He specializes in the diagnosis and treatment of disorders of the spine and peripheral nerves. Dr. Hanna received his medical degree from Cairo University School of Medicine and has been in practice for 24 years. He worked during his residency at the Thomas Jefferson University Hospital and did his fellowships in Spine and Peripheral Nerve at the Mayo Clinic, Rochester and in Spine Surgery at the Washington University, St. Louis. Dr. Hanna has extensive teaching experience and he is an editor of the Journal of Neurosurgery as well as reviewer of numerous international journals.

Book: Peripheral Nerve Entrapments: Clinical Diagnosis and Management

Peripheral Nerve Entrapments: Clinical Diagnosis and Management

Peripheral Nerve Entrapments: Clinical Diagnosis and Management

List Price:$249.00
Featured as a single volume, this is a comprehensive guide to possible nerve entrapment syndromes and their management. Each chapter covers a single nerve, or group of closely related nerves, and goes over the clinical presentation, anatomy, physical exam, differential diagnosis, contributing factors, injection techniques, neurolytic/surgical techniques, treatments of perpetuating factors, and complications.
Nerve entrapments can occur throughout the body and cause headaches, chest pain, abdominal pain, pelvic pain, low back pain, and upper and lower extremity pain. As an example, one of the most common forms of nerve entrapment syndrome, Carpal Tunnel Syndrome, affects roughly 1 in 20 people in the United States, and is only one of several types of entrapment syndromes possible for the median nerve.
Chapters are also extensively illustrated and include 3D anatomical images. The additional online material enhances the book with more than 50 videos – at least 2 for each nerve. This enables readers to easily navigate the book. In addition to a conventional index it includes a “Pain Problems Index” for searching by symptom. Peripheral Nerve Entrapments: Clinical Diagnosis and Management is a long-needed resource for pain physicians, emergency room physicians, and neurologists.

Product Details

  • Published on: 2016-06-11
  • Original language: English
  • Number of items: 1
  • Dimensions: .0″ h x .0″ w x .0″ l, .0 pounds
  • Binding: Paperback
  • 902 pages

Editorial Reviews

About the Author

Andrea M. Trescot, MD
Medical Director – Pain and Headache Center
Anchorage, AK, USA

Dr. Trescot is currently the Chair of the Education Committee of the World Institute of Pain. After 15 years of private practice, she joined academics as a professor and served as the Director of the pain fellowship programs for the University of Washington and the University of Florida/VA Pain Center, before she returned to private practice. She was President of the American Society of Interventional Pain Physicians (ASIPP) from June 2007 to June 2008.  She coauthored the book Pain-Wise: A Patient’s Guide to Pain Management (Hatherleigh Press, 2011), and co-edited the 3 volumes of Pain Medicine & Interventional Pain Management – A Comprehensive Review (American Society of Interventional Pain Physicians Publishing, 2011).

Book: Surgery of the Autonomic Nervous System

Surgery of the Autonomic Nervous System
From Oxford University Press

Surgery of the Autonomic Nervous System

List Price:$165.00

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Autonomic surgery is an important and expanding field within contemporary clinical practice. Surgical therapies influencing the autonomic nervous system have historically entailed disabling various components of its network by injurious methods. More sophisticated techniques have now emerged to allow modulation of neural function by electrical implants or by preservative surgery. This has fuelled the expansion in this field as safer therapies with greater scope for patient benefit have become available. As the potential for precise neural manipulation has advanced, so has the number and diversity of diseases which have become amenable to such therapies.

This book reviews the basic science underpinning the autonomic control of various body systems and the state-of-the-art clinical applications by which these systems are surgically modulated in patients today. Clinical chapters include details of the procedure, operative considerations, outcomes, adverse effect profile, post-operative management of such patients and reflections on personal experience. Autonomic surgery can be applied to a wide variety of diseases affecting large numbers of the population such as angina pectoris, hypertension, orthostatic hypotension, sexual dysfunction, regional pain syndromes, headache and epilepsy.


Product Details

  • Published on: 2016-06-07
  • Original language: English
  • Number of items: 1
  • Dimensions: 6.90″ h x .90″ w x 9.80″ l, .0 pounds
  • Binding: Hardcover
  • 360 pages

Editorial Reviews

About the Author

Jonathan A. Hyam, Neurosurgical Registrar, Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, University College London, UK,Erlick A. C. Pereira, Senior Neurosurgical Registrar, Department of Neurosurgery, Oxford University Hospitals NHS Trust, UK,Alexander L. Green, Consultant Neurosurgeon, Nuffield Department of Surgical Sciences, University of Oxford, UK

Mr Jonathan A. Hyam is a Neurosurgical Registrar at the National Hospital for Neurology and Neurosurgery, Queen Square, London, and a Visiting Academic at Oxford Functional Neurosurgery and the Nuffield Department of Surgical Sciences, University of Oxford. He was awarded his DPhil in 2012 from the Department of Physiology, Anatomy and Genetics.

Mr Erlick A. C. Pereira is a Senior Neurosurgical Registrar at the Department of Neurosurgery, Oxford University Hospitals NHS Trust, UK. He has published around 90 papers in other areas of surgery and neuroscience. Last year, he gained both his FRCS (Neuro.Surg) and was awarded a DM for research into deep brain surgery for pain.

Mr Alexander L. Green is a Consultant Neurosurgeon at the Nuffield Department of Surgical Sciences, University of Oxford, UK. He is currently president of the British Society for Stereotactic and Functional Neurosurgery (BSSFN).

Hoy: IX Curso teórico-práctico de cirugía de los nervios periféricos y del plexo braquial

nervionovleon

León – España acoge el IX Curso teórico-práctico de Cirugía de los nervios periféricos. La cita tendrá lugar los días 11, 12 y 13 de noviembre organizado por el Servicio de Neurocirugía.

Este curso es de ámbito internacional y cuenta con profesores destacados de diferentes hospitales de España y hospitales internacionales como Argentina, Chile, Brasil, Uruguay, México, Italia, y Serbia, además de asistentes de diferentes países.

El curso está dirigido a los médicos con interés en el campo de la cirugía de los nervios periféricos y se desarrollará en el salón de actos del Complejo Asistencial de la capital.

Beca para entrenamiento en Cirugía de Nervios Periféricos en Brazil

Centros de Referencia en Educación Continua acreditados por la FLANC 

Beca Disponible en Rio de Janeiro, Brasil para Cirugía de los Nervios Periféricos.

La División de Neurocirugía del Hospital Universitario Gaffrée y Guinle- HUGG de la Universidad Federal del Estado de Río de Janeiro Neurocirugía – UNIRIO, Brasil, ofrece una beca para entrenamiento en cirugía de los nervios periféricos. El servicio proporciona alojamiento y comida en el hospital universitario.

Los profesionales interesados pueden ponerse en contacto con el Jefe de Servicio de Neurocirugía del Hospital Universitario Gaffrée y Guinle- HUGG de la Universidad Federal del Estado de Río de Janeiro – UNIRIO, Prof. Dr. José Fernando Guedes Corrêa – neuroguedes@yahoo.com.br, para otras informaciones.

Orientaciones generales: 

  1. El neurocirujano interesado en obtener entrenamiento debe pertenecer y / o tener apoyo de una sociedad filiada a la FLANC y seleccionar uno de los Centros de Referencia listados abajo.
  2. Encaminar carta para el neurocirujano responsable por lo servicio del Centro escogido informando su interés en entrenamiento y forneciendo su CV, fechas y subespecialidades de interés. Es recomendable además solicitar información acerca de la posibilidad de recibir acomodación, transporte local y alimentación durante el periodo de entrenamiento.
  3. Enviar los datos obtenidos y la carta de confirmación de aceptación del mismo para la Secretaria General y el Comité de Educación de la FLANC para registro y evaluación.
  4. El candidato recibirá en retorno una carta con informaciones sobre el tipo de apoyo que podrá ser ofrecido por la FLANC y / o la Fundación FLANC.
  5. Será fornecido en todos los casos certificación a los pasantes que presenten informe final de las actividades y trabajos desarrollados, debidamente aprobado pelo jefe del Servicio.