Citations

ABSTRACT Nowadays, consent to use donor bodies for medical education and research is obtained from the body donors and their families before the donation. Recently, the International Federation of Associations of Anatomists (IFAA) published guidelines that could restrict the appearance of cadaveric images in commercial anatomical resources such as textbooks and other educational products. These guidelines state that the donor must expressly consent to using such images for this purpose. Cadaveric photos and drawings made from dissections of cadavers have been used in anatomy textbooks and atlases for hundreds of years. They are invaluable for anatomy students and clinical/surgical practitioners. The IFAA guidelines should not restrict the use of those older books; to do so would infringe the rights of those seeking knowledge from these resources. As the images in such textbooks and atlases are anonymized and are used for teaching and research, and the donors and their families are informed about this before the donation, we believe no additional consent is needed. It is impossible to separate educational from “commercial” usage entirely in any situation, e.g., publications from publishers and the use of cadavers in medical schools. Therefore, our best efforts to avoid unethical use of cadaveric images by following traditional consent processes are still needed so that more people will reap the benefits from them. As senior textbook/atlas authors/editors from over 10 countries, we believe that using cadaveric images in anatomy textbooks is appropriate, and no additional consent should be necessary. Such usage falls within the good faith of professionals using these invaluable gifts.

BACKGROUND: Anterior approaches to the cervical spine are among the most common exposures by which neurosurgeons and orthopedic surgeons access the prevertebral space and ultimately the cervical disk and vertebral bodies. There is a paucity of literature describing the microanatomic fascial planes of the neck with respect to anterior cervical approaches. OBJECTIVE: To delineate the microanatomic connections of the cervical fascial planes pertinent to anterior cervical exposure. METHODS: Using a cadaveric model, original illustrations, the Visible Human Project, and an original surgical video, we demonstrate a stepwise method for identifying the correct planes for anterior cervical exposure. RESULTS: A step-by-step method for identifying the anterior cervical fascial planes intraoperatively is demonstrated. CONCLUSION: A comprehensive understanding of anterior cervical microsurgical anatomy is vital for performing a methodical yet efficient approach to the prevertebral space while minimizing retraction and iatrogenic injury to the surrounding neurovascular structures.

AbstractAlthough superior gluteal nerve (SGN) injury can have significant morbidity, to date, surgical strategies for its repair are scant in the literature. Specifically, neurotization options have not been explored. To address this deficiency in the literature, the current cadaveric feasibility study was performed. Via a transgluteal approach on 16 cadaveric sides, the proximal sciatic nerve and the entrance of the SGN into the gluteus medius and minimus were identified. Additionally, branches from the sciatic nerve to the hamstring muscles were traced proximally to confirm their position in relation to the sciatic nerve as a whole. These branches were cut at the level of the ischial tuberosity and teased away from the sciatic nerve proximally to the greater sciatic foramen and transferred superolateral to the SGN. The diameter of each nerve branch was measured as well as its available length for reaching the SGN. All branches of the sciatic nerve to the hamstring muscles arose from the anteromedial part of the nerve. The mean diameters of the branches to the semimembranosus, semitendinosus, and biceps femoris muscles were 2.1, 1.9, and 1.5 mm, respectively. The mean diameter of the SGN was 3.1 mm and the mean distance from this entrance point to the ischial spine was 7.2 cm. The mean length of the donor nerve was 8.5 cm. Based on our study, use of a tibial‐innervated hamstring branch as a donor for nerve transfer to the SGN is feasible.

Abstract Myocardial bridges are anatomical entities characterized by myocardium covering segments of coronary arteries. In some patients, the presence of a myocardial bridge is benign and is only incidentally found on autopsy. In other patients, however, myocardial bridges can lead to compression of the coronary artery during systolic contraction and delayed diastolic relaxation, resulting in myocardial ischemia. This ischemia in turn can lead to myocardial infarction, ventricular arrhythmias and sudden cardiac death. Myocardial bridges have also been linked to an increased incidence of atherosclerosis, which has been attributed to increased shear stress and the presence of vasoactive factors. Other studies however, demonstrated the protective roles of myocardial bridges. In this study, using systematic review and a meta‐analytical approach we investigate the prevalence and morphology of myocardial bridges in both clinical imaging and cadaveric dissections. We also discuss the pathophysiology, clinical significance, and management of these anatomical entities.

AbstractCervical radiculopathy from uncovertebral joint (UVJ) hypertrophy and nerve root compression often occurs anterior and lateral within the cervical intervertebral foramen, presenting a challenge for complete decompression through anterior cervical approaches owing to the intimate association with the vertebral artery and associated venous plexus. Complete uncinatectomy during anterior cervical discectomy and fusion (ACDF) is a controversial topic, many surgeons relying on indirect nerve root decompression from restoration of disc space height. However, in cases of severe UVJ hypertrophy, indirect decompression does not adequately address the underlying pathophysiology of anterolateral foraminal stenosis. Previous reports in the literature have described techniques involving extensive dissection of the cervical transverse process and lateral uncinate process (UP) in order to identify the vertebral artery for safe removal of the UP. Recent anatomical investigations have detailed the microanatomical organization of the fibroligamentous complex surrounding the UP and neurovascular structures. The use of the natural planes formed from the encapsulation of these connective tissue layers provides a safe passage for lateral UP dissection during anterior cervical approaches. This can be performed from within the disc space during ACDF to avoid extensive lateral dissection. In this article, we present our 10‐year experience using an anatomy‐based microsurgical technique for safe and complete removal of the UP during ACDF for cervical radiculopathy caused by UVJ hypertrophy.

AbstractIntroductionThree‐dimensional printing and virtual simulation both provide useful methods of patient‐specific anatomical modeling for assessing and validating surgical techniques. A combination of these two methods for evaluating the feasibility of spinal instrumentation techniques based on anatomical landmarks has not previously been investigated.Materials and MethodsNineteen anonymized CT scans of the thoracic spine in adult patients were acquired. Maximum pedicle width and height were recorded, and statistical analysis demonstrated normal distributions. The images were converted into standard tessellation language (STL) files, and the T12 vertebrae were anatomically segmented. The intersection of two diagonal lines drawn from the lateral and medial borders of the T12 transverse process (TP) to the lateral border of the pars and inferolateral portion of the TP was identified on both sides of each segmented vertebra. A virtual screw was created and insertion into the pedicle on each side was simulated using the proposed landmarks. The vertebral STL files were then 3D‐printed, and 38 pedicles were instrumented according to the individual posterior landmarks used in the virtual investigation.ResultsThere were no pedicle breaches using the proposed anatomical landmarks for insertion of T12 pedicle screws in the virtual simulation component. The technique was further validated by additive manufacturing of individual T12 vertebrae and demonstrated no breaches or model failures during live instrumentation using the proposed landmarks.ConclusionsEx vivo modeling through virtual simulation and 3D printing provides a powerful and cost‐effective means of replicating vital anatomical structures for investigation of complex surgical techniques.

AbstractGeniculate neuralgia (GN) is an uncommon, but severe, condition that is characterized by excruciating paroxysmal pain in the seventh cranial nerve's cutaneous distribution of general somatic afferent fibers carried through the nervus intermedius (NI). GN becomes a surgical disease in refractory cases of pain after exhaustive medical management. Surgical intervention in the form of microvascular decompression and nerve sectioning has been investigated with good patient outcomes. Despite this, there are limited guidelines on either technique's appropriateness in specific operative scenarios. In our 30‐year experience in GNs surgical management, we have found that a detailed knowledge of the NIs anatomy, variants, and intraoperative surgical anatomic findings are the key to choosing the most appropriate intervention, and may provide the answer to why some patients fail to experience pain relief after surgery. These anatomic variants also may explain why many patients commonly do not experience side effects related to the visceral efferent and special afferent fibers after nerve sectioning.

Ulnar neuropathy at the cubital tunnel is common. However, a rare form of ulnar neuropathy here is due to compression from an accessory muscle, the anconeus epitrochlearis. Reports in the literature regarding the details of this muscle's innervation are vague, so the aim of the present study was to characterize this anatomy more clearly. This was a combined review of magnetic resonance imaging (MRI) from patients with an anconeus epitrochlearis and ulnar neuropathy and cadaveric dissections to characterize the innervation of this variant muscle. A review of 11 patients and three reports of ulnar neuropathy and an anconeus epitrochlearis in the literature revealed no MRI changes consistent with acute denervation of this muscle. However, in two cases, there were signs of chronic denervation of the muscle. Dissection of five cadavers revealed that the nerve supply to the anconeus epitrochlearis originated proximal to the medial epicondyle, traveled parallel to the ulnar nerve, terminated on the deep aspect of this muscle, and had a mean length of 60 mm. This clinicoanatomical study provides evidence that the innervation of the anconeus epitrochlearis is proximal to the muscle and on its deep aspect. Clin. Anat. 32:218–223, 2019. © 2018 Wiley Periodicals, Inc.

Inflammatory etiologies are becoming increasingly recognized as explanations of some neuropathies, especially those occurring in the perioperative period. Although “brachial neuritis” is known to affect extraplexal nerves, accessory nerve palsy following median sternotomy has been attributed to stretch on the nerve. To better elucidate stretch as a potential cause, a cadaveric study was performed. Two patients who developed accessory nerve palsy following median sternotomy are presented to illustrate features consistent with the diagnosis of a perioperative inflammatory neuropathy. Five adult unembalmed cadavers underwent exposure of the bilateral accessory nerves in the posterior cervical triangle. A median sternotomy was performed and self‐retaining retractors positioned. With the head in neutral, left rotation and right rotation, retractors were opened as during surgery while observing and recording any accessory nerve movements. The self‐retaining sternal retractors were fully opened to a mean inter‐blade distance of 13 cm. Regardless of head position, from the initial retractor click to maximal opening there was no gross movement of the accessory nerve on the left or right sides. Opening self‐retaining sternal retractors does not appear to stretch the accessory nerve in the posterior cervical triangle. Based on our clinical experience and cadaveric results, we believe that inflammatory conditions, (i.e., idiopathic brachial plexitis) can involve the accessory nerve, and might be triggered by surgical procedures. Clin. Anat. 31:417–421, 2018. © 2017 Wiley Periodicals, Inc.

Background: The first description of the voluntary motor function of the facial nerve and separate sensory-motor contributions of the trigeminal nerve is most commonly attributed to Charles Bell. However, a review of the original scientific accounts and subsequent historical publications question the validity of this credit. The objective of the present historical analysis is to clarify the contributions of Herbert Mayo toward discovering the functions of the fifth and seventh cranial nerves and to raise awareness of this historical controversy within the medical literature. Methods: Review of Charles Bell's and Herbert Mayo's original dissertations published between 1821 and 1823, and subsequent reports relevant to these primary works. Results: Bell's submissions to the Royal Society of London in 1821 and 1822 describe the seventh nerve as the “respiratory nerve of the face” responsible for involuntary coordination of facial movement with the organs of respiration. Separately, Bell states that the fifth nerve is responsible for sensibility and voluntary movement of the facial muscles. In these accounts, Bell only peripherally alludes to the motor function of the seventh nerve and often comments inaccurately on fifth and seventh cranial nerve innervation. In contrast, in 1822 and 1823, Herbert Mayo first accurately and unequivocally defined the voluntary motor function of the facial nerve and sensory-motor function of the trigeminal nerve on the basis of his detailed experiments. The ultimate transfer of acknowledgment to Bell was rooted in surreptitious reworking of Bell's original dissertations and personal attacks against Mayo rather than arguments of scientific merit. Conclusion: Several notable clinicians and anatomists have contributed to our current understanding of the anatomy and physiology of the facial and trigeminal nerves, including Charles Bell; however, Herbert Mayo should be remembered for first providing a more accurate and clear description of their separate functions.