Nerves of the Thorax: Anatomy, Clinical Signs, and Imaging Findings of Pathological Conditions.

BACKGROUND: Radiological diagnosis of thoracic nerve diseases is difficult because they are rare, and nerves cannot be seen directly on radiological images. The major nerves of the thorax can be listed as the phrenic, vagus, recurrent laryngeal, long thoracic nerve pairs, sympathetic chains, costal nerves, and brachial plexus. Diseases of thoracic nerves have various causes, including traumatic injury, neuromuscular diseases, infection, compression, radiation, drugs, and tumors. OBJECTIVE: This pictorial review aims to describe the anatomic locations of the major thoracic nerves on radiological images, comprehensively describe the causes of thoracic nerve diseases and define the clinical signs and primary and secondary imaging findings of dysfunction of the thoracic nerves. METHODS: This paper was designed to illustrate primary and secondary imaging findings of nerve diseases. Firstly, the normal anatomy of nerves is shown with diagrams. Secondly, we explained primary and secondary imaging features with variable radiological methods, including chest X-Ray, magnetic resonance imaging, and computed tomography. CONCLUSION: Primary findings of nerve diseases can be detected if radiologists are familiar with the courses of the nerves on radiological images. Knowledge of the normal functions of the nerves can aid in diagnosing thoracic nerve diseases identified from secondary imaging findings such as diaphragmatic elevation, muscular atrophy, and winged scapula. It is essential to know the normal anatomy, function, and possible causes of thoracic nerve diseases to make a correct diagnosis and apply the prompt treatment.

Thoracolumbar interfascial plane block for postoperative analgesia in spine surgery: A systematic review and meta-analysis.

INTRODUCTION: Thoracolumbar interfascial plane (TLIP) block has been discussed widely in spine surgery. The aim of our study is to evaluate analgesic efficacy and safety of TLIP block in spine surgery. METHOD: We performed a quantitative systematic review. Randomized controlled trials that compared TLIP block to non-block care or wound infiltration for patients undergoing spine surgery and took the pain or morphine consumption as a primary or secondary outcome were included. The primary outcome was cumulative opioid consumption during 0-24-hour. Secondary outcomes included postoperative pain intensity, rescue analgesia requirement, and adverse events. RESULT: 9 randomized controlled trials with 539 patients were included for analysis. Compared with non-block care, TLIP block was effective to decrease the opioid consumption (WMD -16.00; 95%CI -19.19, -12.81; p<0.001; I2 = 71.6%) for the first 24 hours after the surgery. TLIP block significantly reduced postoperative pain intensity at rest or movement at various time points compared with non-block care, and reduced rescue analgesia requirement ((RR 0.47; 95%CI 0.30, 0.74; p = 0.001; I2 = 0.0%) and postoperative nausea and vomiting (RR 0.58; 95%CI 0.39, 0.86; p = 0.006; I2 = 25.1%). Besides, TLIP block is superior to wound infiltration in terms of opioid consumption (WMD -17.23, 95%CI -21.62, -12.86; p<0.001; I2 = 63.8%), and the postoperative pain intensity at rest was comparable between TLIP block and wound infiltration. CONCLUSION: TLIP block improved analgesic efficacy in spine surgery compared with non-block care. Furthermore, current literature supported the TLIP block was superior to wound infiltration in terms of opioid consumption.

Individualized management of giant anterior meningoceles-case series.

RATIONALE: Anterior spinal meningoceles are rare neuroanatomic abnormality formed by protrusion of the spinal meninges through a defect in the vertebral column. Presently, therapeutic options for anterior spinal meningoceles are still controversial. The objective of this study is to discuss the individualized management of giant anterior spinal meningoceles. PATIENT CONCERNS AND DIAGNOSES: We analyzed 4 patients with anterior spinal meningoceles between 2007 and 2014 in our department by retrospective chart review, two of whom were anterior sacral meningoceles (ASMs), and another2 were intrathoracic meningoceles (ITMs). INTERVENTIONS AND OUTCOMES: Patients mainly presented with compressive symptoms including rectal irritation, dyspnea (patient 3) and fixed neurologic deficits (patient 4). Three out of 4 patients received surgical treatment, one of which underwent reoperation. After surgery, meningoceles in 1 patient completely disappeared. Two patients acquired the stability of the size of the meningoceles. LESSONS: Management of anterior spinal meningoceles often requires precise treatment based on the different conditions of each patient. Surgical intervention has been proposed for the treatment of symptomatic anterior spinal meningoceles. The goal of surgery is to safely disconnect the linkage between the cyst and CSF from subarachnoid space to prevent further enlargement of the cyst or reaccumulating of cystic fluid.

Bloqueos de tronco / Truncal blocks

Truncal blocks have recently been positioned as an alternative to neuraxial analgesia. The injection of local anesthetics in interfascial planes was initially guided by anatomical landmarks, to later evolve towards a more selective administration when guided by ultrasound. Successful execution of truncal blocks requires detailed knowledge of the chest and abdominal walls anatomy. The same logic allows us to understand its potential benefits concerning perioperative analgesia, as well as its limitations and therapeutic margins. Secondary to a growing interest in less invasive techniques and analgesic techniques with a more favorable risk-benefit profile, the available evidence in this field is in continuous development. Thus, in the present review, the technical aspects of these blocks will be evaluated, emphasizing the sonoanatomy, and assessing the best evidence to support the use of each technique.

Los bloqueos de tronco se han posicionado recientemente como una alternativa frente a la analgesia neuroaxial. La inyección de anestésicos locales en planos interfasciales inicialmente fue guiado por referencias anatómicas, para posteriormente evolucionar hacia una administración más selectiva al ser guiada por el ultrasonido. La ejecución exitosa de los bloqueos de tronco requiere un conocimiento detallado de la anatomía de las paredes del tórax y abdomen. Esta misma lógica nos permite entender sus potenciales beneficios en relación con la analgesia perioperatoria, como también sus limitaciones y margen terapéutico. La evidencia disponible está en continuo desarrollo, dado el creciente interés que concitan técnicas menos invasivas y con un perfil de riesgo-beneficio potencialmente más favorable. En la presente revisión se evaluarán los aspectos técnicos de cada bloqueo, poniendo énfasis en la sonoanatomía, y evaluando la mejor evidencia que sustente el uso de cada técnica.

Locoregional Anesthesia of the Thoracic Limbs and Thorax in Small Animals.

The incorporation of nerve stimulation and ultrasound guidance to veterinary regional anesthesia allows accurate performance of techniques to block the thoracic limb and the thorax. When performed correctly, regional anesthesia can either constitute an alternative to the use of opioids and other systemic analgesics, or have a significant opioid-sparing effect. This article provides an overview of some techniques described using objective methods of nerve location, which can be used to provide perioperative locoregional anesthesia and analgesia to the thoracic limb and thorax. The approaches described may be used to decrease the perioperative use of opioids in small animals.

Regional anesthetic techniques for the thoracic limb and thorax in small animals: A review of the literature and technique description.

Veterinary regional anesthesia (RA) has been rapidly increasing in popularity over the last 10 years, as evidenced by the increasing amount of literature available and the continuous development of new techniques in small animals. The introduction of new technologies such as nerve stimulation and ultrasound (which increased the objectivity and precision of the procedure) and the promising beneficial perioperative effects conferred by RA are encouraging clinicians to incorporate these techniques in their daily perioperative anesthetic and analgesic animal care. However, there is a lack of consensus regarding outcomes when RA is used, as well as outcome comparisons between regional anesthetic techniques. Further large-scale clinical studies are still necessary. This article is the first part of a two-part review of RA in small animals, and its aim is to discuss the most relevant studies in the veterinary literature, where objective methods of nerve location have been used, and to illustrate in pictures the currently used techniques for providing RA to the thoracic limb and the thorax in small animals.

The human phrenic nerve serves as a morphological conduit for autonomic nerves and innervates the caval body of the diaphragm.

Communicating fibres between the phrenic nerve and sympathetic nervous system may exist, but have not been characterized histologically and immunohistochemically, even though increased sympathetic activity due to phrenic nerve stimulation for central sleep apnoea may entail morbidity and mortality. We, therefore, conducted a histological study of the phrenic nerve to establish the presence of catecholaminergic fibres throughout their course. The entire phrenic nerves of 35 formalin-fixed human cadavers were analysed morphometrically and immunohistochemically. Furthermore, the right abdominal phrenic nerve was serially sectioned and reconstructed. The phrenic nerve contained 3 ± 2 fascicles in the neck that merged to form a single fascicle in the thorax and split again into 3 ± 3 fascicles above the diaphragm. All phrenic nerves contained catecholaminergic fibres, which were distributed homogenously or present as distinct areas within a fascicle or as separate fascicles. The phrenicoabdominal branch of the right phrenic nerve is a branch of the celiac plexus and, therefore, better termed the "phrenic branch of the celiac plexus". The wall of the inferior caval vein in the diaphragm contained longitudinal strands of myocardium and atrial natriuretic peptide-positive paraganglia ("caval bodies") that where innervated by the right phrenic nerve.

Protease-activated receptor 1 is implicated in irritable bowel syndrome mediators-induced signaling to thoracic human sensory neurons.

Proteases and protease-activated receptors (PARs) are major mediators involved in irritable bowel syndrome (IBS). Our objectives were to decipher the expression and functionality (calcium signaling) of PARs in human dorsal root ganglia (DRG) neurons and to define mechanisms involved in human sensory neuron signaling by IBS patient mediators. Human thoracic DRG were obtained from the national disease resource interchange. Expression of PAR1, PAR2, and PAR4 was assessed by immunohistochemistry and quantitative reverse transcription PCR (RT-qPCR) in whole DRG or in primary cultures of isolated neurons. Calcium signaling in response to PAR agonist peptides (PAR-AP), their inactive peptides (PAR-IP), thrombin (10 U/mL), supernatants from colonic biopsies of patients with IBS, or healthy controls, with or without PAR1 or PAR4 antagonist were studied in cultured human DRG neurons. PAR1, PAR2, and PAR4 were all expressed in human DRG, respectively, in 20%, 40%, and 40% of the sensory neurons. PAR1-AP increased intracellular calcium concentration in a dose-dependent manner. This increase was inhibited by PAR1 antagonism. By contrast, PAR2-AP, PAR4-AP, and PAR-IP did not cause calcium mobilization. PAR1-AP-induced calcium flux was significantly reduced by preincubation with PAR4-AP, but not with PAR2-AP. Thrombin increased calcium flux, which was inhibited by a PAR1 antagonist and increased by a PAR4 antagonist. Supernatants from colonic biopsies of patients with IBS induced calcium flux in human sensory neurons compared with healthy controls, and this induction was reversed by a PAR1 antagonist. Taken together, our results highlight that PAR1 antagonism should be investigated as a new therapeutic target for IBS symptoms.

An anatomic description of intrinsic brachial muscles in the crab-eating fox (Cerdocyon thous, Linnaeus 1776) and report of a variant arterial distribution.

The crab-eating fox (Cerdocyon thous) is a wild canid distributed throughout South America. It is one of the wild canids reported being hit by vehicles and injured in snares, thus inducing trauma or injury to the musculoskeletal system, possibly occurring in the brachial region. The main objective of this research was to provide an anatomic description of the crab-eating fox's intrinsic brachial muscles including shape, origin, insertion, innervation and arterial blood supply, compared with that of the domestic dog. We dissected from superficial to deep two thoracic limbs of seven dead specimens donated to the University of Caldas by CORPOCALDAS. These muscles presented anatomic characteristics similar to those reported in the domestic dog (Canis lupus familiaris) but with a variant in arterial blood supply, allowing us to suggest that surgical procedures that need the knowledge of intrinsic brachial muscles in the crab-eating fox may be homologous to the domestic dog. However, one should consider its variant arterial distribution by part of the collateral radial artery and deep brachial artery to prevent incorrect incisions that may damage these arteries.

How to Wire the Diaphragm: Wholemount Staining Methods to Analyze Mammalian Respiratory Innervation.

Direct or indirect impairment of breathing in humans by diseases or environmental factors can either cause long-term disability and pain, or can ultimately result in death. Automatic respiratory centers in the brainstem control the highly structured process of breathing and signal to a specialized group of motor neurons in the cervical spinal cord that constitute the phrenic nerves. In mammals, the thoracic diaphragm separates the thorax from the abdomen and adopts the function of the primary respiratory musculature. Faithful innervation by the phrenic nerves is a prerequisite for correct functionality of this highly specialized musculature and thus, ultimately, the viability of the entire organism.To analyze the effects of diseases and genetic defects responsible for deleterious or lethal respiratory phenotypes, accurate imaging of respiratory innervation during embryonic development, e.g., in genetically modified mouse models enables the characterization of specific marker genes and pathways that underlie appropriate wiring of the diaphragm. Among the different available immunostaining techniques, wholemount staining methods provide the advantage of clear and faithful three-dimensional information about the location of the antigens of interest. In comparison to routine histological techniques, however, the researcher has to deal with technical challenges, such as antibody penetration, the stability and availability of the antigen, and clearing of the relevant tissue, and the need to be equipped with state-of-the-art microscope equipment.In this methodological chapter, we explain and share our expertise concerning wholemount processing of mouse embryos and thoracic diaphragms for the analysis of mammalian respiratory innervation.

Self-organized Notch dynamics generate stereotyped sensory organ patterns in Drosophila.

The emergence of spatial patterns in developing multicellular organisms relies on positional cues and cell-cell communication. Drosophila sensory organs have informed a paradigm in which these operate in two distinct steps: Prepattern factors drive localized proneural activity, then Notch-mediated lateral inhibition singles out neural precursors. Here we show that self-organization through Notch signaling also establishes the proneural stripes that resolve into rows of sensory bristles on the fly thorax. Patterning, initiated by a gradient of Delta ligand expression, progresses through inhibitory signaling between and within stripes. Thus, Notch signaling can support self-organized tissue patterning as a prepattern is transduced by cell-cell interactions into a refined arrangement of cellular fates.

Cross-sectional Imaging Anatomy and Pathologic Conditions Affecting Thoracic Nerves.

While in many cases they are not directly visualized, awareness of the thoracic nerves and their courses at cross-sectional imaging is important for radiologists. An understanding of the normal function of each nerve is important, as many patients present with neurologic signs and symptoms that can be used to reinforce search patterns for disease and detection of supportive radiologic abnormalities. In the case of primary neoplasms, understanding the expected presence of a nerve in the location of a mass can enhance and improve the accuracy of differential diagnoses. Even in the absence of neurologic symptoms, secondary involvement of these structures by malignancy or close proximity to other intrathoracic disease can prompt significant alterations in oncologic or surgical management. The major components of the thoracic nervous system with which the thoracic radiologist must be familiar are the phrenic, vagus, recurrent laryngeal, intercostal, and long thoracic nerves in addition to the sympathetic chain and brachial plexus. The anatomic structure and course of each component are described including its major functions. Major clinical signs and symptoms attributable to nerve dysfunction or disease are reviewed as well as any associated radiologic signs. Emphasis is placed on primary and secondary malignant involvement of the nerves and iatrogenic and traumatic injuries. Online supplemental material is available for this article. ©RSNA, 2016.

The sacral autonomic outflow is sympathetic.

A kinship between cranial and pelvic visceral nerves of vertebrates has been accepted for a century. Accordingly, sacral preganglionic neurons are considered parasympathetic, as are their targets in the pelvic ganglia that prominently control rectal, bladder, and genital functions. Here, we uncover 15 phenotypic and ontogenetic features that distinguish pre- and postganglionic neurons of the cranial parasympathetic outflow from those of the thoracolumbar sympathetic outflow in mice. By every single one, the sacral outflow is indistinguishable from the thoracolumbar outflow. Thus, the parasympathetic nervous system receives input from cranial nerves exclusively and the sympathetic nervous system from spinal nerves, thoracic to sacral inclusively. This simplified, bipartite architecture offers a new framework to understand pelvic neurophysiology as well as development and evolution of the autonomic nervous system.

Thoracodorsal nerve transfer for triceps reinnervation in partial brachial plexus injuries.

PURPOSE: To report the clinical outcomes of thoracodorsal nerve (TDN) transfers to the triceps motor branches for elbow extension restoration in patients with partial brachial plexus injuries (BPI). METHODS: Eight male patients of mean age 23 years and suffering from a partial BPI underwent direct coaptation of the TDN to the nerve of the upper medial and long heads of the triceps, an average 6 months after their accident. RESULTS: Seven patients achieved M4 elbow extension strength and one patient M3, according to the BMRC scale, after a mean follow-up of 21 months. DISCUSSION: Direct TDN transfer might be a valid surgical procedure for the restoration of elbow extension in patients with partial BPI.

[Clinical diagnostic features of surgical treatment for thoracic outlet syndrome].

The thoracic outlet syndrome is characterized by a variety of clinical signs due to multiple causes resulting in compression of a neurovascular bundle in a relatively narrow anatomical space. Despite the frequently encountered clinical symptoms, inadequate attention is paid to their analysis, and their diagnostic and surgical aspects require a modern approach. The study included 46 patients. The main clinical sign is a persistent pain syndrome of the cervico-occipital localization that affects the shoulder girdle, suprascapular and infrascapular regions and spreads to the arm in combination with trophic, sensory and vascular disorders. SCT angiography of the superior thoracic outlet structures has been used as a priority instrumental method of research. The macro- and micro factors of compression are the main cause for the development of neurological symptoms, and their removal is the main task of surgical treatment. Surgical approaches were planned depending on the nature and extent of injury. 36 patients underwent 42 surgical interventions. The proper assessment of the neurological status in combination with modern paraclinical diagnostic methods and selection of an adequate surgical approach provided satisfactory outcomes in 33 cases.

[Vascular relationships of the right great splanchnic nerve in the thorax]. / Rapports vasculaires thoraciques du nerf grand splanchnique droit.

AIM: The surgical assumption of responsibility of the pancreatic pain requires either a truncular coelioscopic or radicular neurectomy of greater splanchnic nerves (gsn). The goal of our work is to describe the way and relations of the right gsn which are variable and rarely described. This constitutes an undeniable peroperational hemorrhagic risk during splanchnicectomy. MATERIAL AND METHODS: After a double side thoracotomy and a bilateral sterno-clavicular desarticulation on 15 adult cadaveric subjects preserved by method of Winckler we removed the sterno-costal drill plate as well as the ventral rib arch and proceeded to a mediastinal evisceration of the thorax. Then we respected only the thoracic aorta and the oesophagus, the azygos venous system, the thoracic duct and the thoracic sympathetic chain. In some of the subjects, the azygos vein was injected (after catheterization of its stick) using gelatine coloured with blue paint. We studied the way and vascular relations of the right gsn. We measured the transverse distances between the origin of the gsn on one hand and the longitudinal axes of the azygos vein and the thoracic duct on the other hand. RESULTS: The relations of the right gsn trunk during its way related to the azygos vein in particular its constitutive origin and its affluents: ascending lumbar vein and twelfth intercostal vein. Sometimes the thoracic duct even a lymphatic node was near the gsn in the posterior infra-mediastinal space. A classification of the way and vascular relations of the right gsn in the thorax identified 3 anatomical types. The average distances separating the right gsn on one hand from the azygos vein and the thoracic duct on the other hand were respectively 5.7 mm and 11.2 mm. CONCLUSION: The vascular relations of the right gsn are very variable from one subject to another but primarily venous, sometimes lymphatic. They concerned the great thoracic vessels whose respect is essential in particular at the time of mini-invasive access procedure for a cœlioscopic splanchnicectomy.

Using skin sympathetic nerve activity to estimate stellate ganglion nerve activity in dogs.

BACKGROUND: Stellate ganglion nerve activity (SGNA) is important in cardiac arrhythmogenesis. However, direct recording of SGNA requires access to the thoracic cavity. Skin of upper thorax is innervated by sympathetic nerve fibers originating from the stellate ganglia and is easily accessible. OBJECTIVE: The purpose of this study was to test the hypothesis that thoracic skin nerve activity (SKNA) can be used to estimate SGNA. METHODS: We recorded SGNA and SKNAs using surface electrocardiogram leads in 5 anesthetized and 4 ambulatory dogs. Apamin injected into the right stellate ganglion abruptly increased both right SGNA and SKNA in 5 anesthetized dogs. We integrated nerve activities and averaged heart rate in each 1-minure window over 10 minutes. We implanted a radiotransmitter to record left SGNA in 4 ambulatory dogs (2 normal, 1 with myocardial infarction, 1 with intermittent rapid atrial pacing). After 2 weeks of recovery, we simultaneously recorded the SKNA and left SGNA continuously for 30 minutes when the dogs were ambulatory. RESULTS: There was a positive correlation [average r = 0.877, 95% confidence interval (CI) 0.732-1.000, P <.05 for each dog] between integrated skin nerve activity (iSKNA) and SGNA (iSGNA) and between iSKNA and heart rate (average r = 0.837, 95% CI 0.752-0.923, P <.05). Similar to that found in the anesthetized dogs, there was a positive correlation (average r = 0.746, 95% CI 0.527-0.964, P <.05) between iSKNA and iSGNA and between iSKNA and heart rate (average r = 0.706, 95% CI 0.484-0.927, P <.05). CONCLUSION: SKNAs can be used to estimate SGNA in dogs.