Jonas Hydman

Bio: Jonas Hydman is an academic researcher from Karolinska University Hospital. The author has contributed to research in topics: Recurrent laryngeal nerve & Reinnervation. The author has an hindex of 10, co-authored 12 publications receiving 338 citations. Previous affiliations of Jonas Hydman include Karolinska Institutet.

Collateral reinnervation by the superior laryngeal nerve after recurrent laryngeal nerve injury.

Abstract: This study investigates the role of the intact superior laryngeal nerve (SLN) in the reinnervation process of one of the laryngeal muscles, the posterior cricoarytenoid muscle (PCA), following recurrent laryngeal nerve (RLN) injury. Using a chronic RLN injury model in the adult rat, PCA reinnervation was assessed by retrograde double-tracing techniques in combination with electrophysiology and immunohistochemistry of muscle sections. The results demonstrate that the PCA receives dual innervation from both laryngeal nerves even in the uninjured system. Functionally significant collateral reinnervation originates from intact SLN fibers following RLN injury, mainly due to intramuscular sprouting rather than by recruitment of more motor neurons. This may be important when choosing surgical and/or medical treatment for patients with RLN injury.

Diagnosis and prognosis of iatrogenic injury of the recurrent laryngeal nerve.

Abstract: Objectives:Following perioperative injury to a macroscopically intact recurrent laryngeal nerve (RLN), there are two possible intraneural injury types: 1) axonal injury, including disruption of axons, and 2) conduction block, only affecting the Schwann cells and the nodes of Ranvier. In this study, it was hypothesized that the functional outcome after RLN injury may depend on the type of nerve injury.Methods:Fifteen patients with acute postoperative unilateral RLN paralysis were prospectively studied. Electrophysiological examination (laryngeal electromyography) was used to differentiate between the two types of nerve injury. Vocal fold motions were monitored by repeated laryngoscopy during the study period (up to 6 months). Three of the patients with axonal injury were treated with the regeneration-promoting agent nimodipine.Results:The patients with conduction block all recovered normal vocal fold motion, whereas patients with axonal injury within the nerve had a significantly worse outcome. The 3 patie...

Nimodipine improves reinnervation and neuromuscular function after injury to the recurrent laryngeal nerve in the rat.

Abstract: Objectives:Injury of the recurrent laryngeal nerve (RLN) is associated with a high degree of neuronal survival, but leads to various levels of vocal fold motion impairment or laryngeal synkinesis, which has been attributed to misdirected reinnervation of the target muscles in the larynx or aberrant, competing reinnervation from adjacent nerve fibers The aim of the present study was to evaluate the impact of the regeneration-promoting agent nimodipine on reinnervation and neuromuscular function following RLN crush injuryMethods:Sixty adult rats were randomized into nimodipine-treated or untreated groups and then underwent RLN crush injury Reinnervation of the posterior cricoarytenoid muscle (PCA) was assessed by electrophysiological examination, retrograde tracing of lower motor neurons before and after injury, and quantification of neuromuscular junctions in the PCA muscleResults:At 6 weeks after injury, the nimodipine-treated animals showed significantly enhanced neuromuscular function and also demon

Nimodipine and Microsurgery Induced Recovery of the Vocal Cord after Recurrent Laryngeal Nerve Resection

Abstract: Transection of the recurrent laryngeal nerve leads to permanent palsy of the vocal cord. Experimental studies have confirmed that nimodipine increases the pace of axonal regeneration. We present a case of a 19-year-old male, suffering a thyroid cancer disease, who was subjected to unilateral resection of the recurrent laryngeal nerve during surgery. The nerve was repaired with a nerve graft and the patient further treated with nimodipine for 3 months. Evaluation of the patient showed normalization of voice, movement of the vocal cord on the injured side, and electromyography evidence of reinnervation of the larynx muscles at 15 months after surgery.

Recovery of laryngeal function after intraoperative injury to the recurrent laryngeal nerve

Abstract: Loss of function in the recurrent laryngeal nerve (RLN) during thyroid/parathyroid surgery, despite a macroscopically intact nerve, is a challenge which highlights the sensitivity and complexity of laryngeal innervation. Furthermore, the uncertain prognosis stresses a lack of capability to diagnose the reason behind the impaired function. There is a great deal of literature considering risk factors, surgical technique and mechanisms outside the nerve affecting the incidence of RLN paresis during surgery. To be able to prognosticate recovery in cases of laryngeal dysfunction and voice changes after thyroid surgery, the surgeon would first need to define the presence, location, and type of laryngeal nerve injury. There is little data describing the events within the nerve and the neurobiological reasons for the impaired function related to potential recovery and prognosis. In addition, very little data has been presented in order to clarify any differences between the transient and permanent injury of the RLN. This review aims, from an anatomical and neurobiological perspective, to provide an update on the current understandings of surgically-induced injury to the laryngeal nerves.

Gray's Anatomy

Abstract: MEDICAL LITERATURE has been deluged during the past few years with books and papers on penicillin; but a book which has been produced under the general editorship of Sir Alexander Fleming himself represents a complete and authoritative summary of penicillin therapy as it stands today.' The book contains a series of independent contributions by \"experienced and eminent men who have worked with penicillin in Great Britain\". Their opinions and practical methods differ slightly, and there is some overlapping; but these are not disadvantageous, comparison and contrast lending interest to the reading. In the first or general section of the book Fleming contributes two chapters, one on the history and development of penicillin, introducing some interesting sidelights in the romance of discovery, the other on the bacteriological control of penicillin therapy. In both chapters the information is set out in meticulous detail and with a clarity and simplicity which can be enjoyed by all readers. Fleming also gives the right perspective to the place of penicillin amongst the antibiotics and lays down the principles of treatment. Both chapters are well illustrated and are the most outstanding in the book. Included in this first section also are chapters on the chemistry and manufacture of penicillin and its pharmacy, pharmacology and methods of administration. The second section of the book is entirely clinical, giving each author's view on the use of penicillin therapy in a disease or an infection of some particular region of the body. The entire range of peniCillin-sensitive conditions is considered in twenty authoritative and clearly written chapters; these contain many references and illustrations. Dental and veterinary diseases are also given fairly full consideration. The final section is a condensed resume of much of the preceding chapters and is written for. the general practttioner. This chapter is superttuous: it does not contain enough detall to be of much practical value. The book as a Whole, however, will undoubtedly be considered a classical contribution to medical literature and is strongly recommended, not only because of the general interest of its topic, but as a reference book on penicillin therapy of hitherto unequalled excellence. The typography, although conforming to war economy standards, is clear and the paper is good. There is an excellent list of references and the index is satisfactory.

Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans

Abstract: Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. We aim to discuss the major methodological bias of methods used for the evaluation of oxidative stress in humans. There is a lack of consensus concerning the validation, standardization, and reproducibility of methods for the measurement of the following: (1) ROS in leukocytes and platelets by flow cytometry, (2) markers based on ROS-induced modifications of lipids, DNA, and proteins, (3) enzymatic players of redox status, and (4) total antioxidant capacity of human body fluids. It has been suggested that the bias of each method could be overcome by using indexes of oxidative stress that include more than one marker. However, the choice of the markers considered in the global index should be dictated by the aim of the study and its design, as well as by the clinical relevance in the selected subjects. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

Abstract: Objective:To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.Background:Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in th