Laryngeal nerve “anastomoses”

Laryngeal nerves have been observed to communicate with each other and forma variety of patterns. These communications have been studied extensively and have been of particular interest as it may provide an additional form of innervation to the intrinsic laryngeal muscles. Variations noted in incidence may help explain the variable position of the vocal folds after vocal fold paralysis. This study aimed to examine the incidence of various neural communications and to determine their contribution to the innervation of the larynx. Fifty adult cadaveric en-bloc laryngeal specimens were studied. Three different types of communications were observed between internal and recurrent laryngeal nerves viz. (1) Galen’s anastomosis (81%): in 13%, it was observed to supply the posterior cricoarytenoid muscle; (2) thyroarytenoid communication (9%): this was observed to supply the thyroarytenoid musclein 2% of specimens and (3) arytenoid plexus (28%): in 6%, it supplied a branch tothe transverse arytenoid muscle. The only communication between the externaland recurrent laryngeal nerves was the communicating nerve (25%). In one lefthemi-larynx, the internal laryngeal nerve formed a communication with the externall aryngeal nerve, via a thyroid foramen. The neural communications that exist in the larynx have been thought to play a role in laryngeal innervation. The results of this study have shown varying incidences in neural communications. Contributions fromthese communications have also been noted to various in trinsic laryngeal muscles which may be a possible factor responsible for the variable position of the vocalfolds in certain cases of vocal fold paralysis

A non-recurrent inferior laryngeal nerve in a man undergoing thyroidectomy: a case report

<p>Abstract</p> <p>Introduction</p> <p>A non-recurrent variant of the inferior laryngeal nerve has been seldom reported. These reports are mostly based on cadaveric dissection studies or large chart review studies in which the emphasis is placed on the determination of the frequency of the variation, and not on the clinical appearance of this variant. We graphically describe the intraoperative identification of a non-recurrent inferior laryngeal nerve.</p> <p>Case Presentation</p> <p>A 44-year old Caucasian man was referred to the Head and Neck Surgery Outpatient Clinic with the diagnosis of a nodular mass in his left thyroid lobe that had been growing for one year. A fine needle aspiration puncture was compatible with thyroid papillary cancer. It was decided that the patient should undergo total thyroidectomy. During surgery, a non-recurrent right inferior laryngeal nerve was noted. This nerve emanated from the right vagus nerve, entering the larynx 3 cm after its origin. The nerve did not show a recurrent course. The nerve on the left side had a normal configuration. The surgery and post-operative period were uneventful, and the patient had no change in his voice.</p> <p>Conclusion</p> <p>This paper allows those interested to become acquainted with the normal intraoperative appearance of a non-recurrent inferior laryngeal nerve. This will undoubtedly be of significance for all of those performing invasive diagnostic and surgical procedures in the neck and upper thoracic regions, in order to minimize the risk of iatrogenic injury to this nerve. This is of extreme importance, since a unilateral lesion of this nerve may result in permanent hoarseness, and a bilateral lesion may lead to aphonia and life-threatening dyspnea.</p

Thoracic origin of a sympathetic supply to the upper limb: the ‘nerve of Kuntz’ revisited

An understanding of the origin of the sympathetic innervation of the upper limb is important in surgical sympathectomy procedures. An inconstant intrathoracic ramus which joined the 2nd intercostal nerve to the ventral ramus of the 1st thoracic nerve, proximal to the point where the latter gave a large branch to the brachial plexus, has become known as the ‘nerve of Kuntz’ (Kuntz, 1927). Subsequently a variety of sympathetic interneuronal connections down to the 5th intercostal space were reported and also described as the nerve of Kuntz. The aim of this study was to determine: (1) the incidence, location and course of the nerve of Kuntz; (2) the relationship of the nerve of Kuntz to the 2nd thoracic ganglion; (3) the variations of the nerve of Kuntz in the absence of a stellate ganglion; (4) to compare the original intrathoracic ramus with sympathetic variations at other intercostal levels; and (5) to devise an appropriate anatomical classification of the nerves of Kuntz. Bilateral microdissection of the sympathetic chain and somatic nerves of the upper 5 intercostal spaces was undertaken in 32 fetuses (gestational age, 18 wk to full term) and 18 adult cadavers. The total sample size comprised 99 sides. Sympathetic contributions to the first thoracic nerve were found in 60 of 99 sides (left 32, right 28). Of these, 46 were confined to the 1st intercostal space only. The nerve of Kuntz (the original intrathoracic ramus) of the 1st intercostal space had a demonstrable sympathetic connection in 34 cases, and an absence of macroscopic sympathetic connections in 12. In the remaining intercostal spaces, intrathoracic rami uniting intercostal nerves were not observed. Additional sympathetic contributions (exclusive of rami communicantes) were noted between ganglia, interganglionic segments and intercostal nerves as additional rami communicantes. The eponym nerve of Kuntz should be restricted to descriptions of the intrathoracic ramus of the 1st intercostal space. Any of these variant sympathetic pathways may be responsible for the recurrence of symptoms after sympathectomy surgery

Thoracic splanchnic nerves: implications for splanchnic denervation

Splanchnic neurectomy is of value in the management of chronic abdominal pain. It is postulated that theinconsistent results of splanchnicectomies may be due to anatomical variations in the pattern of splanchnicnerves. The advent of minimally invasive and video-assisted surgery has rekindled interest in the frequencyof variations of the splanchnic nerves. The aims of this study were to investigate the incidence, origin andpattern of the splanchnic nerves in order to establish a predictable pattern of splanchnic neural anatomythat may be of surgical relevance. Six adult and 14 fetal cadavers were dissected (n¯38). The origin of thesplanchnic nerve was bilaterally asymmetrical in all cases. The greater splanchnic nerve (GSN) was alwayspresent, whereas the lesser splanchnic nerve (LSN) and least splanchnic nerve (lSN) were inconsistent (LSN,35 of 38 sides (92%); LSN, 21 of 38 sides (55%). The splanchnic nerves were observed most frequentlyover the following ranges: GSN, T6±9: 28 of 38 sides (73%); LSN, when present, T10±11: (10 of 35 sides(29%); and lSN, T11±12: 3 of 21 sides (14%). The number of ganglionic roots of the GSN variedbetween 3 and 10 (widest T4±11; narrowest, T5±7). Intermediate splanchnic ganglia, when present, wereobserved only on the GSN main trunk with an incidence of 6 of 10 sides (60%) in the adult and 11 of 28sides (39%) in the fetus. The higher incidence of the origin of GSN above T5 has clinical implications,given the widely discussed technique of undertaking splanchnicectomy from the T5 ganglion distally. Thisapproach overlooks important nerve contributions and thereby may compromise clinical outcome. In thelight of these variations, a reappraisal of current surgical techniques used in thoracoscopic splanchnicectomyis warranted

Cervico-Thoracic Ganglion: Its Clinical Implications

Lesions of the cervicothoracic ganglion (CTG) result in interruption of sympathetic fibersto the head, neck, upper limb, and thoracic viscera. The accurate understanding of theanatomy of the CTG is relevant to sympathectomy procedures that may be prescribed incases where conventional intervention has failed. This study documents the incidence anddistribution of the CTG to avoid potential complications such as Horner’s syndrome andcardiac arrhythmias. This study utilized 48 cadavers, in which a total of 89 sympatheticchains were dissected. The inferior cervical ganglion (ICG) and the first thoracic ganglionwas fused in 75 cases (84.3%) to form the CTG. It was present bilaterally in 48 of thesespecimens (65.3%). Three different shapes of CTG were differentiated, viz. spindle, dumbbell,and an inverted ‘‘L’’ shape. The dumbbell and inverted ‘‘L’’ shapes demonstrated adefinite ‘‘waist’’ (i.e., a macroscopically visible union of the ICG and T1 components ofthe CTG). Rami from the CTG was distributed to the brachial plexus, the subclavian andvertebral arteries, the brachiocephalic trunk, and the cardiac plexus. This study demonstratesa high incidence of a double cardiac sympathetic nerve arising from CTG. It istherefore imperative that in the technique of sympathectomy, for intractable anginal pain, thesurgeon excises both these rami but does not destroy the ganglion itself. The ever-improvingtechnology in endoscopic surgery has made investigations into the nuances of the anatomy ofthe sympathetic chain essential. Clin. Anat. 19:323–326, 2006

Thoracoscopy: A New Era for Surgical Anatomy

In this new era of minimal access surgery, advances in optics and illumination haveestablished thoracoscopic sympathectomy as a pre-eminent procedure, including a safe andefficient technique for upper limb sympathectomy. The success of thoracoscopy will doubtlessensure that a greater number of these procedures will be carried out and will put someof the daunting technical challenges posed by traditional open surgical procedures to rest. Thethoracoscopic era affords the surgical anatomist a new challenge: to move the teaching ofliving anatomy to a higher level