Landmarks of the facial nerve: implications for parotidectomy.

Facial nerve paralysis is a daunting potential complication of parotid surgery and is widely reported. Knowledge of the key landmarks of the facial nerve trunk is essential for safe and effective surgical intervention in the region of the parotid gland. In current practice, wide ranges of landmarks are used to identify the facial nerve trunk, however, there is much debate in the literature about the safety and reliability of each of these landmarks. The aim of this study, therefore, was to evaluate the relation of the surrounding anatomical structures and surgical landmarks to the facial nerve trunk. The anatomical relationship of the facial nerve trunk to the surrounding structures was determined after micro-dissection on 40 adult cadavers. The shortest distances between the facial nerve and the "tragal pointer", attachment of the posterior belly of digastric muscle, tympanomastoid suture, external auditory canal, transverse process of the axis, angle of the mandible and the styloid process were measured. In addition, these distances were compared in the right and left sides, males and females and edentulous and non-edentulous mandibles. The distance of the facial nerve trunk from each of the surrounding landmarks ranged from (mm): tragal pointer, 24.3 to 49.2 (mean 34); posterior belly of digastric, 9.7 to 24.3 (mean 14.6); external auditory canal, 7.3 to 21.9 (mean 13.4); tympanomastoid suture, 4.9 to 18.6 (mean 10.0); styloid process, 4.3 to 18.6 (mean 9.8); transverse process of the axis, 9.7 to 36.8 (mean 16.9); angle of the mandible, 25.3 to 48.69 (mean 38.1). The length of the facial nerve trunk from its point of exit from the stylomastoid foramen to its bifurcation into upper and lower divisions ranged from (mm) 8.6 to 22.8 (mean 14.0). The results demonstrated that the posterior belly of digastric, tragal pointer and transverse process of the axis are consistent landmarks to the facial nerve trunk. However, it should be noted that the tragal pointer is cartilaginous, mobile, asymmetrical and has a blunt, irregular tip. This study advocates the use of the transverse process of the axis as it is easily palpated, does not require a complex dissection and ensures minimum risk of injury to the facial nerve trunk.

Cervico-thoracic ganglion: its clinical implications.

Lesions of the cervicothoracic ganglion (CTG) result in interruption of sympathetic fibers to the head, neck, upper limb, and thoracic viscera. The accurate understanding of the anatomy of the CTG is relevant to sympathectomy procedures that may be prescribed in cases where conventional intervention has failed. This study documents the incidence and distribution of the CTG to avoid potential complications such as Horner's syndrome and cardiac arrhythmias. This study utilized 48 cadavers, in which a total of 89 sympathetic chains were dissected. The inferior cervical ganglion (ICG) and the first thoracic ganglion was fused in 75 cases (84.3%) to form the CTG. It was present bilaterally in 48 of these specimens (65.3%). Three different shapes of CTG were differentiated, viz. spindle, dumbbell, and an inverted "L" shape. The dumbbell and inverted "L" shapes demonstrated a definite "waist" (i.e., a macroscopically visible union of the ICG and T1 components of the CTG). Rami from the CTG was distributed to the brachial plexus, the subclavian and vertebral arteries, the brachiocephalic trunk, and the cardiac plexus. This study demonstrates a high incidence of a double cardiac sympathetic nerve arising from CTG. It is therefore imperative that in the technique of sympathectomy, for intractable anginal pain, the surgeon excises both these rami but does not destroy the ganglion itself. The ever-improving technology in endoscopic surgery has made investigations into the nuances of the anatomy of the sympathetic chain essential.

The anatomical rationale for an upper limb sympathetic blockade: preliminary report.

Stellate ganglion blockade (SGB) has long been considered pivotal in the diagnosis, determination of prognosis and management of chronic regional pain syndrome (CRPS) by sympathectomy. To date a variety of SGB techniques have been described. An inaccurate SGB may mislead clinicians and deny patients a potentially beneficial procedure. In order to obtain a predictable and readily reproducible blockade of the upper limb, a modified anterior technique was evaluated. This modified sympathetic block was performed in 10 adult cadavers (n=19 sides). Toluidine blue solution (10 ml) was injected and, following median sternotomy, the extent of spread of dye was evaluated. In one cadaver a dual block using both the modified and the standard techniques was performed. Proximal spread to the seventh cervical vertebra was noted in all blocks; distal spread extended to the neck of the third rib (n=3), neck of the fourth rib 7 (n=15) and neck of the seventh rib (n=1). Medial spread was greater than lateral spread and extended to the vertebral bodies (vagus nerve was also stained) while lateral spread in all cases "blocked" lower roots of the brachial plexus and was consistently noted beyond the usual location of the nerve of Kuntz. This modified technique demonstrated that the lower cervical ganglia and proximal thoracic sympathetic trunk were consistently stained. It should be noted that the spread was sufficiently lateral to block the nerve of Kuntz. The pitfalls of this technique aside, we suggest that this technique be reserved for therapeutic purposes, particularly when sympathectomy is not possible.

Thoracoscopy: a new era for surgical anatomy.

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

The sympathetic contributions to the cardiac plexus.

Cardiac sympathetic denervation for intractable angina pectoris in patients unsuitable for conventional revascularization is currently gaining popularity since this procedure may be performed via minimally invasive surgery. A thorough understanding of cardiac innervation and its variations is crucial to successfully effect cardiac denervation. This study aimed to demonstrate the cervical and thoracic sympathetic contributions to the cardiac plexus. The cervical and thoracic sympathetic trunks in 21 fetuses and eight adults were micro-dissected bilaterally and documented ( n=58 sides). The superior cervical cardiac ramus originated from the superior cervical ganglion (present in all specimens) in 53% of cases. The middle cervical ganglion (incidence 81%) gave rise to the middle cervical cardiac ramus in 88% of cases. The cervico-thoracic ganglion (incidence 85%) gave the cervico-thoracic cardiac ramus in 84%. In the thoracic region, four cardiac rami arose from the T2-T6 segment of the thoracic sympathetic trunk. All cervical and thoracic cardiac rami were traced consistently to the deep cardiac plexus. Khogali et al.'s (1999) success of limited T2-T4 sympathectomy in relieving pain at rest of patients with intractable angina pectoris appears to indicate that a significant afferent pain pathway from the heart is selectively interrupted. The variability in pattern of the cervical ganglia, cardiac rami and cervical contributions to the cardiac plexus does not appear to affect the outcome of limited sympathectomy. The complexity of cardiac pain pathways is not fully understood. The study is continuing and attempts to contribute to defining these cardiac neuronal pathways.

A thoracoscopic view of the nerve of Kuntz.

The nerve of Kuntz and alternate neural pathways (ANPs) have long been considered crucial for upper limb sympathetic supply. However, at thoracoscopy, these structures are neither consistently identified nor searched for. This is probably reflective of the effectiveness of an isolated second thoracic ganglionectomy for upper limb sympathectomy. We present the case of a 19-year-old male who underwent a second thoracic ganglionectomy for palmar hyperhidrosis. On the left side, approximately 2.5 cm lateral to the typically located sympathetic chain, a filamentous structure (one-quarter the diameter of the sympathetic chain), identified as the nerve of Kuntz, was noted coursing across the neck of the second rib.

Thoracic splanchnic nerves: implications for splanchnic denervation.

Splanchnic neurectomy is of value in the management of chronic abdominal pain. It is postulated that the inconsistent results of splanchnicectomies may be due to anatomical variations in the pattern of splanchnic nerves. The advent of minimally invasive and video-assisted surgery has rekindled interest in the frequency of variations of the splanchnic nerves. The aims of this study were to investigate the incidence, origin and pattern of the splanchnic nerves in order to establish a predictable pattern of splanchnic neural anatomy that may be of surgical relevance. Six adult and 14 fetal cadavers were dissected (n = 38). The origin of the splanchnic nerve was bilaterally asymmetrical in all cases. The greater splanchnic nerve (GSN) was always present, whereas the lesser splanchnic nerve (LSN) and least splanchnic nerve (ISN) were inconsistent (LSN, 35 of 38 sides (92%); LSN, 21 of 38 sides (55%). The splanchnic nerves were observed most frequently over the following ranges: GSN, T6-9: 28 of 38 sides (73%); LSN, when present, T10-11: (10 of 35 sides (29%); and ISN, T11-12: 3 of 21 sides (14%). The number of ganglionic roots of the GSN varied between 3 and 10 (widest T4-11; narrowest, T5-7). Intermediate splanchnic ganglia, when present, were observed only on the GSN main trunk with an incidence of 6 of 10 sides (60%) in the adult and 11 of 28 sides (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. This approach overlooks important nerve contributions and thereby may compromise clinical outcome. In the light of these variations, a reappraisal of current surgical techniques used in thoracoscopic splanchnicectomy is warranted.

Bedside application of an ultrasensitive urine test for HCG in patients with suspected ectopic pregnancy.

One hundred and seven patients with suspected ectopic pregnancy were tested for HCG at the bedside using the Tandem Icon. The test was performed by ward doctors with no formal laboratory experience. The patients were managed conservatively or by surgery as dictated by the clinical picture and the Icon test result. Retrospective categorisation of the 107 patients by laboratory analysis and clinical outcome showed that 21 were pregnant (17 ectopic, 4 intrauterine) and 86 non-pregnant. At the bedside the Icon was reported as negative in one pregnant patient and three patients who were not pregnant were found to give Icon-positive results. In the laboratory the Icon correctly categorised all patients. Three of the four discrepant results were found to be a direct result of the operator's inexperience in analytical procedure and interpretation. The Tandem Icon HCG urine assay can reliably be used at the bedside of patients with suspected ectopic pregnancy provided that the operator has had sufficient experience in its use.