Cervical necrotizing fasciitis: descriptive, retrospective analysis of 59 cases treated at a single center.

To provide retrospective, descriptive information on patients with cervical necrotizing fasciitis treated at a single center during the years 1998-2014, and to evaluate the outcome of a newly introduced treatment strategy. Retrospective analysis of clinical data obtained from medical records. Mortality, pre-morbidity, severity of illness, primary site of infection, type of bacteria, time parameters. The observed 3-month mortality was 6/59 (10 %). The most common initial foci of the infection were pharyngeal, dental or hypopharyngeal. The most common pathogen was Streptococcus milleri bacteria within the Streptococcus anginosus group (66 % of the cases). Using a combined treatment with early surgical debridement combined with hyperbaric oxygen treatment, it is possible to reduce the mortality rate among patients suffering from cervical necrotizing fasciitis, compared to the expected mortality rate and to previous historical reports. Data indicated that early onset of hyperbaric oxygen treatment may have a positive impact on survival rate, but no identifiable factor was found to prognosticate outcome.

Quantification of Trapezius Muscle Innervation During Neck Dissections: Cervical Plexus Versus the Spinal Accessory Nerve.

OBJECTIVES: Despite increasing use of selective, nerve-sparing surgical techniques during neck dissections, the reported rate of postoperative paralysis of the trapezius muscle is still high. The aim of the study is to measure and compare motor inflow to the trapezius muscle, in order to better understand the peripheral neuroanatomy. METHODS: Intraoperative nerve monitoring (electroneurography) in patients undergoing routine neck dissection (n=18). The innervation of the 3 functional parts of the trapezius muscle was mapped and quantified through compound muscle action potentials. RESULTS: In 18/18 (100%) of the patients, the spinal accessory nerve (SAN) innervated all parts of the trapezius muscle. In 7/18 (39%) of the patients, an active motor branch from the cervical plexus was detected, equally distributed to all functional parts of the trapezius muscle, at levels comparable to the SAN. CONCLUSIONS: Compared to the SAN, branches from cervical plexus provide a significant amount of neural input to all parts of the trapezius muscle. Intraoperative nerve monitoring can be used in routine neck dissections to detect these branches, which may be important following surgical injury to the SAN.

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

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.

New animal model for assessment of functional laryngeal motor innervation.

OBJECTIVES: The functional motor innervation of the larynx is not fully understood because of the complexity of the peripheral neuroanatomy. Since the late 19th century, there has been controversy regarding the role of the superior laryngeal nerve, which may have wider motor projections than are currently acknowledged. The aim of this study was to develop a large animal model to characterize and quantify the functional motor input to the intrinsic laryngeal muscles. METHODS: We performed invasive electrophysiology (evoked electromyography) in normal pigs. RESULTS: The thyroarytenoid, lateral cricoarytenoid, and posterior cricoarytenoid muscles receive dual innervation from both the superior and recurrent laryngeal nerves, whereas the cricothyroid muscle is innervated only by the superior laryngeal nerve. CONCLUSIONS: The dual innervation pattern from both laryngeal nerves supports the concept of a laryngeal nerve plexus. The motor input through the external branch of the superior laryngeal nerve was surprisingly high. The animal model presented here may be used in future investigations of laryngeal reinnervation following nerve injury.

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

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 patients who were treated with nimodipine all recovered normal or near-normal vocal fold mobility despite the more severe axonal injury. CONCLUSIONS: In contrast to previous reports, our results show that laryngeal electromyography is a reliable tool for diagnosing the type of injury within the injured RLN, making it possible to predict the functional outcome in these patients. On the basis of the results, a future randomized study on nimodipine treatment for RLN axonal injury is suggested.

Preserved regeneration and functional recovery of the injured recurrent laryngeal nerve after secondary surgical repair in adult rats.

OBJECTIVES: Transection of the recurrent laryngeal nerve (RLN) is accompanied by poor functional recovery, despite primary repair, because of regeneration difficulties. Nimodipine can promote regeneration, but it is not yet clear whether preoperative treatment is necessary. It is also not clear whether surgical repair following RLN injury may be performed in a second procedure, with preserved regeneration. This study investigated the time window for secondary surgical repair of the transected RLN and the need for preoperative administration of nimodipine. METHODS: In adult rats, the left RLN was transected and repaired at time intervals up to 3 weeks after transection, in combination with nimodipine treatment starting either before or after the operation. Regeneration and neuromuscular recovery were assessed by electrophysiology, retrograde tracing, and immunohistochemistry. RESULTS: Similar (whether 0, 2, or 7 days) regenerative results were obtained when the RLN was repaired up to 1 week after injury, given nimodipine administration, whereas fewer motor neurons managed to regenerate after nerve repair at 3 weeks after the initial transection. No beneficial effect was detected from preoperative nimodipine administration. CONCLUSIONS: Provided that nimodipine is administered, surgical reconstruction of the RLN can be performed within 1 week after the initial nerve trauma, with preserved neuromuscular function. Nimodipine may be administered at the time of RLN transection injury.

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

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.

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

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 injury. METHODS: 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 muscle. RESULTS: At 6 weeks after injury, the nimodipine-treated animals showed significantly enhanced neuromuscular function and also demonstrated a higher number of motor neurons in the brain stem that had reinnervated the PCA, compared to the untreated animals. The somatotopic organization of ambiguus motor neurons innervating the larynx was similar before injury and after reinnervation. CONCLUSIONS: Nimodipine improves regeneration and neuromuscular function following RLN injury in the adult rat, and could be of use in future strategies following RLN injury.