Anterior Division Research Articles

Dorsal root ganglia, neural crest migration, and spinal cord form in snakes

The classic view of the vertebrate dorsal root ganglion is that it arises from trunk neural crest cells that migrate to positions lateral to the spinal cord, sending axons dorsally into the spinal cord and dendrites ventrally to meet with motor axons in the ventral root to form spinal nerves. As a result, the ganglion ends up lying in the dorsal root of the spinal nerve. Serial histological sections of parts of the trunk of juveniles of different snake species revealed that the ganglia lie distal to the junction of dorsal and ventral roots of spinal nerves and outside the neural canal. The anatomical position of spinal ganglia in snakes suggests that regulation of trunk neural crest migration in snakes differs from that in the model endotherms in which it has been most thoroughly explored. Dorsal roots have no distinct rootlets and the span of root entry to the spinal cord is short compared to that of ventral rootlets in the same segment. Comparing early developmental stages to juvenile spinal cords shows an increased separation of spinal nerve root sites and ventral migration of the ganglion in later development. Dorsal rami of the spinal nerves leave directly from the dorsal edge of the ganglion, and the ventral ramus leaves from the ventral tip of the ganglion. How these features relate to the developmental regulation of ganglion form and position and the extraordinary locomotor capabilities of the snake trunk are unclear.

Modeling Surgical Management of Uterine Atony Induced Postpartum Hemorrhage using Cadaver Dissection

IntroductionThere is a well‐documented disconnect that medical students experience when applying preclinical anatomical knowledge to clinical applications.1 According to the United States National Inpatient Sample, postpartum hemorrhage (PPH) carries an overall incidence of up to 3% of all U.S. deliveries; this study designates uterine atony as the most common etiology of PPH, causing at least 80% of PPH cases.2Thus, fourth year medical students preparing to enter into the specialty of obstetrics and gynecology should have in vivo exposure to the surgical management of uterine atony induced PPH prior to beginning residency. Modeling arterial ligation of the anterior division of the internal iliac artery using a cadaver model is a practical approach that most resembles an in vivo illustration of PPH surgical management while also maintaining a safe, controlled environment.ObjectiveIn efforts to provide fourth year medical students with exposure to PPH management, create a guide for ligation of the internal iliac artery’s anterior division using a cadaver model.Material and MethodsDissection was completed by two fourth year HWCOM medical students anticipating entry into the specialty of obstetrics and gynecology. After completion of anterior abdominal wall dissection and peritoneal entry, GI organ were retracted for full visualization of genitourinary structures. The following arteries were identified and skeletonized in the following fashion: common iliac artery, internal iliac artery, anterior division of the internal iliac artery, umbilical artery, obturator artery, and uterine artery. The anterior division of the internal iliac artery was identified and ligated 2 cm below the bifurcation of the common iliac artery to avoid unintentional ligation of the superior gluteal artery. A picture of the arterial ligation site was captured.Results/ImagesProper arterial ligation site of the internal iliac artery’s anterior division can be visualized in the appendix.Conclusion and Significance/ImplicationSurgical management of PPH requires both anatomical knowledge of arterial and pelvic anatomy but also spatial familiarity of structures in vivo. Performing the surgical management of PPH on a cadaver model could provide fourth year medical students an opportunity to learn the appropriate sites and steps and surgical arterial ligation in a less pressured environment before entering residency. Future implications of this study could combine virtual learning tools, such as anatomy mobile applications, to further aid in medical education’s exposure to PPH management and associated anatomy.

Variant Femoral Nerve: The Path Beneath the Iliacus Muscle and Into Neuropathic Symptoms

Introduction and ObjectiveOriginating from the lumbar plexus, the femoral nerve has a native course along the anterior surface of the iliacus then travels deep to the inguinal ligament, branching into separate anterior and posterior divisions that provide innervation to the anterior thigh muscles (Figure 1). Clinically, the spatial relationship between the iliopsoas complex and the femoral nerve has been noted for the potential risk of entrapment and compressive neuropathies. Variations in the femoral nerve course following surgical and medical interventions can produce symptoms related to muscle weakness and sensory loss in patients. Relevant literature regarding variant femoral nerve distributions is most often related to aberrant slips of the iliacus muscle and following surgical or medical intervention. In this case study, we describe a variation in the descent of the femoral nerve that travels within the belly of the iliacus muscle without evidence of an aberrant slip or surgical intervention and discuss the clinical implications and appropriate non‐invasive osteopathic treatment options.MaterialsThis anatomical variation was revealed in one donor being evaluated at Sam Houston State University College of Osteopathic Medicine’s anatomy lab. The donor was previously dissected by medical students for a first‐year anatomy course. The iliacus and surrounding structures were left intact. Additional dissection necessary for this study was performed from March 2021 to April 2021.ResultsIn a 70‐year‐old male cadaver, the right femoral nerve originated from the lumbar plexus, descended, and then bifurcated (Figure 2A). Most of the femoral nerve remained within the Iliacus muscle (Figure 2B) while a small portion of the femoral nerve followed the typical course anterior to the iliacus (Figure 2C). The bulk of the femoral nerve traveled within the iliacus, exiting inferior to the inguinal ligament, then merged with the smaller portion of the nerve (Figure 2D). The left femoral nerve followed a typical course.Significance/ConclusionPrevious discussions report an aberrant slip of the iliacus splitting the femoral nerve and having the potential for nerve compression, although unlikely due to the smaller muscle belly involved. This highlighted variant is significant because the bulk of the femoral nerve remains beneath the iliacus as it crosses over the pubic eminence. This pathway would be predisposed to a greater degree of compression against the pubic eminence, with potential for certain movements to increase these forces.This patient presentation is hypothesized to include anterior thigh weakness during hip flexion and knee extension activities, such as stair‐climbing, as well as sensory loss to the anteromedial thigh and medial leg via the saphenous nerve. Sensation to the lateral thigh should remain intact as the lateral femoral cutaneous nerve would be unaffected. conservative treatments, such as osteopathic manipulative techniques, could be an effective form of treatment. Techniques including counterstrain to the psoas and iliacus or muscle energy to the hip flexors could lessen such nerve compression and improve patient symptoms.Awareness of this variation could provide clinicians with another potential diagnosis to consider when managing femoral neuropathy, as well as rationale for a non‐invasive treatment option.

Anatomy of the L5 nerve root in the pelvis for safe sacral screw placement: a cadaveric study.

Previous reports have focused on the complications of L5 nerve root injury caused by anterolateral misplacement of the S1 pedicle screws. Anatomical knowledge of the L5 nerve root in the pelvis is essential for safe and effective placement of the sacral screw. This cadaveric study aimed to investigate the course of the L5 nerve root in the pelvis and to clarify a safe zone for inserting the sacral screw. Fifty-four L5 nerve roots located bilaterally in 27 formalin-fixed cadavers were studied. The ventral rami of the L5 nerve roots were dissected along their courses from the intervertebral foramina to the lesser pelvis. The running angles of the L5 nerve roots from the centerline were measured in the coronal plane. In addition, the distances from the ala of the sacrum to the L5 nerve roots were measured in the sagittal plane. The authors found that the running angles of the L5 nerve roots changed at the most anterior surface of the ala of the sacrum. The angles of the bilateral L5 nerve roots from the right and left L5 intervertebral foramina to their inflection points were 13.77° ± 5.01° and 14.65° ± 4.71°, respectively. The angles of the bilateral L5 nerve roots from the right and left inflection points to the lesser pelvis were 19.66° ± 6.40° and 20.58° ± 5.78°, respectively. There were no significant differences between the angles measured in the right and left nerve roots. The majority of the L5 nerves coursed outward after changing their angles at the inflection point. The distances from the ala of the sacrum to the L5 nerve roots in the sagittal plane were less than 1 mm in all cases, which indicated that the L5 nerve roots were positioned close to the ala of the sacrum and had poor mobility. All of the L5 nerve roots coursed outward after exiting the intervertebral foramina and never inward. To prevent iatrogenic L5 nerve root injury, surgeons should insert the S1 pedicle screw medially with an angle > 0° toward the inside of the S1 anterior foramina and the sacral alar screw laterally with an angle > 30°.

A cadaveric study on the origins of the uterine artery

The uterine artery (UA) is a visceral branch from the anterior division of the internal iliac artery (IIA). Knowledge of the variant origins of this artery is critical during radiologic and surgical procedures of the pelvis, especially those involving the uterus, where managing blood flow is vital. Though its path and destination are well agreed upon, the origin of the UA differs notably, and has led many anatomists to create numerous descriptions for the distinctive variation. This project investigated the origin of the UA in the unique South Texas population of female cadavers donated to the UT Health San Antonio and established a fundamental and comprehensive classification system of the origin of this vessel which readily accommodates previous systems while improving its descriptive terminology. As the UA was identified, its origin was classified into three different ranks—primary, secondary, or tertiary. Primary‐ranked vessels originated directly from the internal iliac artery (IIA) and took three different formations as a separate branch, bifurcation with another vessel, or trifurcation with two other vessels. Secondary‐ranked UAs originated from primary vessels and tertiary‐ranked vessels originated from secondary vessels. 58.97% (23/39) of the UAs studied arose from the IIA as a primary‐ranked vessel, 38.5% (15/39) as a secondary rank, and 2.6% (1/39) as a tertiary rank. 21.7% (5/23) of primary‐ranked UAs took origin from IIA as a separate branch, 56.5% (13/23) as bifurcation with another vessel and 21.7% (5/23) as trifurcation with two other vessels. The UA originated as a bifurcation with the umbilical artery (UmbA) in 13/13 cases. UA origin as a trifurcation was observed in 3 different patterns: 40% (2/5) with the UmbA and the superior vesical artery (SVA); 40% (2/5) with the UmbA and vaginal artery (VA); 20% (1/5) with SVA and the internal pudendal artery (IPA). 93.3% (14/15) of secondary‐ranked UA arose from the UmbA and 6.7% (1/15) from the IPA. We observed a single tertiary ranked UA arising from the vaginal artery (VA), which took origin from the UmbA, a branch of the anterior division of the IIA. It is imperative that the prevalence of these primary‐ranked UA bifurcations and trifurcations be further established since permanent occlusion at the vessel’s origin may subsequently lead to necrosis of unintended tissues. Larger sample sizes amongst differing populations may lead to the discovery of uncommon bifurcation and trifurcation patterns, or with similar vessels in differing proportions. It would also be important to translate the evaluation criteria used in this study into 3D and 4D digital subtraction angiography or cone‐beam computed tomography software for clinical studies. Increasing awareness of the variant origins of the UA will ultimately improve patient treatment outcomes, particularly for female reproductive health.

Ultrasound-guided selective trunk block (SeTB): a cadaver anatomic study to evaluate the spread of dye after a simulated injection

Background and objectivesRecent reports suggest that a selective trunk block (SeTB) can produce sensorimotor blockade of the entire upper extremity, except for the T2 dermatome. There are no data demonstrating...

A new juvenile Yamaceratops (Dinosauria, Ceratopsia) from the Javkhlant Formation (Upper Cretaceous) of Mongolia.

Here we report a new articulated skeleton of Yamaceratops dorngobiensis (MPC-D 100/553) from the Khugenetjavkhlant locality at the Shine Us Khudag (Javkhlant Formation, ?Santonian-Campanian) of the eastern Gobi Desert, Mongolia, which represents the first substantially complete skeleton and the first juvenile individual of this taxon. The specimen includes a nearly complete cranium and large portions of the vertebral column and appendicular skeleton. Its skull is about 2/3 the size of the holotype specimen, based on mandibular length. Its juvenile ontogenetic stage is confirmed by multiple indicators of skeletal and morphological immaturity known in ceratopsians, such as the long-grained surface texture on the long bones, the smooth external surface on the postorbital, open neurocentral sutures of all caudal vertebrae, a large orbit relative to the postorbital and jugal, the low angle of the lacrimal ventral ramus relative to the maxillary teeth row, narrow frontal, and straight ventral edge of the dentary. Osteohistological analysis of MPC-D 100/553 recovered three lines of arrested growth, implying around 3 years of age when it died, and verified this specimen’s immature ontogenetic stage. The specimen adds a new autapomorphy of Yamaceratops, the anteroventral margin of the fungiform dorsal end of the lacrimal being excluded from the antorbital fossa. Furthermore, it shows a unique combination of diagnostic features of some other basal neoceratopsians: the ventrally hooked rostral bone as in Aquilops americanus and very tall middle caudal neural spines about or more than four times as high as the centrum as in Koreaceratops hwaseongensis, Montanoceratops cerorhynchus, and Protoceratops andrewsi. The jugal with the subtemporal ramus deeper than the suborbital ramus as in the holotype specimen is also shared with A. americanus, Liaoceratops yanzigouensis, and juvenile P. andrewsi. Adding 38 new scorings into the recent comprehensive data matrix of basal Neoceratopsia and taking into account the ontogenetically variable characters recovered Y. dorngobiensis as the sister taxon to Euceratopsia (Leptoceratopsidae plus Coronosauria). A second phylogenetic analysis with another matrix for Ceratopsia also supported this position. The new phylogenetic position of Y. dorngobiensis is important in ceratopsian evolution, as this taxon represents one of the basalmost neoceratopsians with a broad, thin frill and hyper-elongated middle caudal neural spines while still being bipedal.

Bilateral superficial cervical plexus block with conscious sedation for thyroid surgery

Total thyroidectomy can safely be performed by bilateral superficial cervical plexus blockade which is a regional anesthetic technique to anaesthetize superficial branches of the anterior primary rami of cervical 3-5 spinal nerves. Conscious sedation with this anesthetic technique enhance safe and faster recovery compared to general anesthesia (GA) with endotracheal intubation which is traditionally employed technique for thyroidectomy. This randomized active control trial was conducted in the department of Anaesthesia, Analgesia and Intensive care medicine, Bangabandhu Sheikh Mujib Medical University from January to December 2018 to compare perioperative outcome between bilateral superficial cervical plexus blockade and GA technique during total thyroidectomy. Total 60 patients of American Society of Anesthesiol- ogists Classification grade I and II who were selected for thyroidectomy were randomly divided into Group-A(n=30) and Group-B (n=30). Group A received with 0.5% bupivacaine and 1% lignocaine; and group B received general anesthesia during total thyroidectomy. Heart rate, systolic blood pressure, diastolic blood pressure mean arterial blood pressure , oxygen satura- tion (SPO2) were recorded and compared between the groups. Operative site bleeding, surgeon’s satisfaction & post operative pain were measured with Boezaart Scoring system, Likert scale & visual analogue scale repectively; and compared between two groups. During induction, systolic and diastolic blood pressure were high in group B and reduced in group A which were statistically significant. Systolic and diastolic blood pressure was significantly reduced in Group-A in comparison to Group-B after 5 minutes, 30 minutes, 45 minutes and at the end of operation. Bilateral superficial cervical plexus blockade reduced pain more effective- ly than GA group & it was statistically significant. Mean value of bleeding score were also statis- tically significant in Group-A. Regarding surgeons’ satisfaction, there was no statistically signif- icant difference between the groups. Bilateral superficial cervical plexus block with conscious sedation provided better outcome in terms of perioperative hemodynamics, pain and surgical site bleeding compared to general anaesthesia. BSMMU J 2021; 14(4): 104-108

Q&A: Rating Brachial Plexus Injury

QUESTION: How do I assess impairment for a patient with a brachial plexus injury involving the middle and lower trunks but not the upper trunk?ANSWER: Rating impairment for a brachial plexus injury using the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, is straightforward. Table 15-20, Brachial Plexus Impairment: Upper Extremity Impairments (6th ed, 434-435), lists impairments for the entire brachial plexus, as well as upper, middle, and lower trunks individually, each in different rows. If both middle and lower trunks were injured, each would be rated, and the upper limb impairments combined per instructions number 8 and 13 on page 481.The classic anatomic description of the brachial plexus describes the C5 through T1 nerve roots as contributing to the plexus, with the middle trunk composed of just the C7 nerve root, while the lower trunk is formed by the fusion of the C8 and T1 nerve roots. However, this “classic plexus” is found in only 37% to 77% of cadaver dissections.1 The two most common anatomic anomalies are “prefixed” and “postfixed” plexi. In a prefixed plexus, the C4 nerve root has a substantial contribution, while the T1 nerve root has minimal or no contribution to the plexus. In a postfixed plexus, there is minimal or no C5 contribution to the plexus and a substantial T2 nerve root contribution. Thus, standard charts of the nerve root contributing to individual peripheral nerves or trunks of the plexus may not correspond to an individual patient's anatomy.Assuming C7 supplies sensation to the middle finger and C8 and T1 to the little finger and ulnar forearm, rating sensory deficit without obvious duplication is more straightforward.Rating the motor deficit is more complex. No nerve to a single muscle leaves either the middle or lower trunk of the classic plexus. Hence, one cannot determine whether the injury does or does not involve the trunk by involvement or sparing that nerve, respectively. Normal paraspinal muscles on needle electromyography (EMG) with clear denervation in limb muscles helps localize the lesion as distal to the nerve root division into anterior and posterior primary rami. Stimulating proximal to the plexus at the level of individual nerve root during nerve conduction testing is challenging and rarely done. Magnetic resonance imaging (MRI) may not clarify the level of injury. However, in cases of open trauma with immediate surgery to repair vascular damage, the operative report may accurately describe the extent of any concomitant brachial plexus injury.Because most muscles are innervated by more than one nerve root—a fail-safe redundancy in the case of injury—residual weakness in any one muscle may be from injury to the lower trunk, middle trunk, or both. Hence, it is wise to rate the severity of the motor loss on physical examination by assuming any one muscle is innervated by nerves derived from only one trunk.For example, the triceps is classically described as innervated by the C7, C8, and partially by the T1 nerve roots. If the triceps has grade 3/5 weakness on examination, and if that is considered middle trunk weakness when rating the middle trunk, and lower trunk weakness when rating the lower trunk, the motor deficit rating will be duplicative (rating the same weakness twice).Similarly, classic innervation charts show C7 and C8 contributing to the flexor carpi ulnaris, flexor digitorum profundus, abductor digiti minimi, first dorsal interosseous, extensor digitorum communis, and extensor carpi ulnaris. Logically weakness in these muscles should be attributed to and rated as either middle or lower trunk motor deficits, but not both.Brachial plexus injuries are uncommon, and it takes considerable time and thought to thoroughly examine and correctly rate the residuals.

Are the nerves supplying the anterior sacroiliac joint nociceptive?

Sacroiliac joint (SIJ) pain is often difficult to diagnose. Moreover, while its anatomical characteristics have been well studied, its innervation and the contributions of particular nerves remain controversial, especially in relation to posterior joint innervation. To our knowledge, previous studies have not investigated the presence of nociceptive fibres in the nerves innervating the anterior SIJ. Eight adult cadaveric sides underwent dissection of the anterior SIJ. Adjacent anterior rami were examined for branches to the anterior SIJ. Any branches contributing to the anterior SIJ were measured and then resected. These samples were fixed in formalin and substance P was identified immunohistologically. On all sides, 1-2 small branches (mean diameter of 0.33 mm) arose from the posterior aspect of the L4 anterior ramus (12.5%), the L5 anterior ramus (62.5%), or simultaneously from both the L4 and L5 anterior rami (25%). These branches had a mean length of 13.5 mm. All histological samples contained nerve tissue. All samples of nerve fibres traveling to the anterior SIJ were positive for diffuse substance P reactivity. There were no histological differences between sides or sex. Each of the branches identified as travelling to the SIJ exhibited similar positivity for substance P. This cadaveric study demonstrates that the anterior SIJ nerve fibres carry pain fibres. This new knowledge has application to patients with SIJ syndrome and to its various treatments including interventional approaches to SIJ pain.

Ultrasound-guided multiple-injection costotransverse block for mastectomy and primary reconstructive surgery. A study protocol.

Post-operative pain amelioration following breast cancer surgery is inconsistent. The novel multiple-injection costotransverse block (MICB) mimics the thoracic paravertebral block by possible anaesthetising the ventral rami of the thoracic spinal nerves and the sympathetic trunk. Proof of concept has been determined in a cadaveric study and needs further clinical testing. This double-blinded, randomised and placebo-controlled study investigates the efficacy of the ultrasound-guided MICB versus placebo in 36 patients undergoing unilateral mastectomy and primary subpectoral reconstruction surgery. Oral pre-operative medicine is standardised for all patients. Active group is pre-operatively administered MICB with three injections of each 10ml of ropivacaine (5mg/ml). The placebo group is pre-operatively administered three injections of each 10ml of saline (0.9%). Standard general anaesthesia is induced and 30min before emergence 0.2μg/kg total body weight sufentanil IV, 1g of paracetamol IV and 4mg of ondansetron IV (post-operative nausea and vomiting, PONV, prophylaxis) will be administered. All patients are provided with a patient-controlled analgesia pump with morphine. The primary aim is total morphine consumption in the first 24 post-operative hours. Secondary aims are pain intensity, duration of the block, patient satisfaction, side effects, time to ambulation, time to discharge, and quality of recovery. Recruitment began in November 2019 and is expected to finish ultimo 2021. Results are expected to be published in an international peer-reviewed medical journal. The results will hopefully provide a substantial contribution to the knowledge of these new 'intertransverse process blocks' providing regional anaesthesia of the thoracic wall.

Interhemispheric Asymmetry of Lateral Sulcus and its Significance in Adult Human Brains: A Cadaveric Study from Southern India

Introduction: Cerebral hemispheres are the two main parts of human brain. Though, the cerebral hemispheres may appear to be identical, one hemisphere is functionally dominant over the other. They also exhibit physical variations. The dominance may be due to lateralisation of cortical functions. In about 90% of the total population, the left hemisphere is dominant over the right where the speech and language areas are located. These areas are situated within the Pars Opercularis (PO) and Pars Triangularis (PT) in the dominant hemisphere of the Lateral Sulcus (Sylvian Fissure). The interhemispheric asymmetry of the Sylvian Fissure (SF) may be the basis of cerebral dominance for language, which is less studied in human beings. These asymmetries are relative and vary according to the functions concerned. Therefore, knowledge of the interhemispheric asymmetries is helpful in neurological diagnosis and management. Aim: To measure the length of the lateral sulcus and its rami on both hemispheres and to study their interhemispheric asymmetry. Materials and Methods: A cross-sectional pilot study was done on 30 whole brains of embalmed adult human cadavers irrespective of sexes taken from the Institute of Anatomy of Madras Medical College, Tamil Nadu, India, between the months of June to August, 2017. The lateral sulcus was measured on the superolateral surface of the brain. All measurements were taken with the help of a thin copper wire placed on the surface, its ends being held in position with artery forceps. The wire was then placed on a graduated metal scale and the lengths of the anterior ascending, anterior horizontal, posterior rami and total length of the lateral sulcus were noted. A data sheet was made using Microsoft excel software and the mean length of each ramus was calculated. Results: The mean total length of the SF was noted to be 8.4±0.51 cm on the right side and 8.8±0.56 cm on the left. The mean length of stem of lateral sulcus was 2.5±0.4 cm and 2.6±0.3 cm on the right and left side, respectively. The mean length of the anterior ascending ramus was found to be 2.7±0.3 cm on the right side and 3.13±0.3 cm on the left side. The mean length of the anterior horizontal ramus was found to be 2.34±0.37 cm on the right side and 2.55±0.4 cm on the left side. The mean length of the posterior ramus was found to be 5.6±0.65 cm on the right side and 6.1±0.63 cm on the left side. Conclusion: The SF and their rami of the left side were longer than of the right side in most specimens. This signifies the functional asymmetry between right and left cerebral hemispheres which may be related to language lateralisation of human brain. This interhemispheric difference has been implicated in various genetic syndromes and behavioural disorders in children particularly involving language milestone.

An ethical perspective to using bone grafts in dentistry

An ethical perspective to using bone grafts in dentistry

ВАРИАНТЫ АНАТОМИИ ПЛЕЧЕВОГО СПЛЕТЕНИЯ

The brachial plexus (BP) is a complex of nerve structures arising from the ventral rami of the lower four cervical (C5-C8) and upper thoracic (Th1) spinal nerves. The number of described variants of BP has been increasing every decade. This paper analyzes the world literature data on the anatomy of the BP. The sources of information used included: PubMed, Web of Science, Scopus, MEDLINE, EMBASE, Biosis Citation Index, SciELO Citation Index, RSCI data bases. It was noted that the anatomy of the BP is variable, its 'classic' variant of the structure occurs in less than 50% of cases. In other cases, there were significant differences in structure and course from the 'classic' version. Keywords: Brachial plexus, trunk, bundle, variant anatomy, 'classic' scheme.

Modified Clavipectoral Fascial Plane Block to The Rescue: Polytrauma Patient with Brachial Plexus Injury Undergoing Awake Clavicle Surgery

Modified Clavipectoral Fascial Plane Block to The Rescue: Polytrauma Patient with Brachial Plexus Injury Undergoing Awake Clavicle Surgery

Variations of Ulnar Nerve in the Forearm and Hand: A Review of the Literature and Clinical Significance.

The ulnar nerve originates from the anterior division of the lower trunk of the brachial plexus which continues as the medial cord and gives off branches to the forearm and the hand with motor and sensory fibers. The objective of the current study is to assemble the recognized anatomical variations of the ulnar nerve (UN) and underline their clinical impact. A literature search was undertaken via PubMed database, using the term: "ulnar nerve AND variations." Classical anatomical textbooks were also used for the normal anatomy of the UN. A total of 23 articles met the inclusion criteria, 16 of which are included in this review. Fifty-four additional articles provided useful information according to the aim of this review. Of great interest is the communication between the UN and the radial nerve (RN) in the forearm, as well as the communication between the UN and the median nerve (MN) in both forearm and hand. Furthermore, variations of the UN were observed in the hand and the classification of the UN compression was also described according to the point of the neuropathy. These collecting data are categorized into five tables. Additional aberrations were also included in this review. According to literature, the UN is characterized by numerous variations of its course and branches. Therefore, good knowledge of the normal anatomy is essential. Moreover, the anomalies are of particular importance due to their significant clinical implications and should be taken into consideration by the surgeons during surgical procedures in this region.

The Anterolateral Cervical Atlanto-Occipital Plexus: A Novel Finding with Application to Skull Base and Spine Surgery and Pain Disorders of the Head and Neck

We have described a novel nerve plexus of the upper neck. By exploring how the individual components of this specific anterolateral nerve plexus communicate with each other, patient care could be improved regarding the preoperative diagnosis, intraoperative navigation, and minimally invasive treatment. Using a surgical microscope, 11 adult cadaveric heads (22 cadaveric hemi-sides) were dissected. The region of the junction between the atlanto-occipital and craniocervical junctions was explored, specifically, the innervation of this region via adjacent nerve connections. Branches from these regional nerve sources were analyzed for interconnections, and, when found, these branches were documented and measured. A delicate nerve plexus was found overlying the anterolateral C1-C2 junction in all specimens. The plexus was contributed by the sympathetic trunk, vagus nerve, hypoglossal nerve, and C1 and C2 ventral rami. We termed this plexus the anterolateral cervical atlanto-occipital (ALCAO) plexus. On all but 2 cadaveric hemi-sides (91%), the C2 ventral ramus provided the most input into the plexus, with 1-2 branches. On 2 cadaveric hemi-sides, the C1 ventral ramus was the primary contributor and, on average, this nerve contributed 1-2 branches to the plexus. For 8 cadaveric hemi-sides (36.4%), the C1 fibers that are known to travel with the hypoglossal nerve and be distributed to the geniohyoid and thyrohyoid muscles arose from C1 nerve fibers that first traversed the ALCAO plexus. The sympathetic trunk contributed 1-4 lateral branches, with most of these arising superiorly from the superior cervical ganglion. The vagus nerve contributed 1-2 lateral branches and the hypoglossal nerve contributed 1-2 anteromedial branches. This plexus was located more or less lateral to the sympathetic trunk and superior cervical ganglion and medial to the transverse process of C1 and C2. The plexus innervated the rectus capitis lateralis, rectus capitis anterior, and lateral atlanto-occipital joint and, on 4 cadaveric hemi-sides, the atlantoaxial joint. Additionally, small branches were seen traveling to the anterior atlantoaxial and anterior atlanto-occipital membranes on 55% and 77.2% of the cadaveric hemi-sides, respectively. On 6 hemi-sides, very small branches from the ALCAO plexus ended in the periosteum over the anterolateral aspect of the anterior arch and transverse process of the C1 vertebra. It is important to recognize that the course of these interneural connections varies and could result in unforeseen complications during surgical procedures. A comprehensive knowledge of these neural connections will be useful when considering surgery and evaluating pathology of the neck and skull base.

Aortic arch uncrossing using a tracheal resection procedure

One category of vascular rings is the right aortic arch associated with the diverticulum of Kommerell from which the left subclavian artery usually originates. In some cases, the right aortic arch crosses behind the trachea and the esophagus from right to left. The trachea and esophagus are compressed by the right aortic arch, the left ligamentum, and the posterior crossing aorta, which causes the typical symptoms of noisy breathing, dyspnea on exertion, dysphagia, and frequent upper respiratory tract infections. Division of the atretic arch segment between the diverticulum of Kommerell and the left common carotid artery may relieve the symptoms temporarily but does not relieve the compression produced by this vascular abnormality. Indeed, at the age of 10 months, this patient underwent anterior arch division and posterior aortopexy via a posterolateral thoracotomy in order to relieve the compression caused by the vascular ring. Several months after the initial operation, the patient had recurrent respiratory symptoms as a result of residual vascular compression from the circumflex arch. A CT scan and airway endoscopy confirmed tracheal compression; in addition, the tracheoscopy showed tracheomalacic changes in the compressed segment of the trachea. To relieve the symptoms and the compression, we decided to resect the tracheomalacic segment of the trachea and translocate the aortic arch anterior to the trachea and esophagus.

Transdeltoid Approach to Axillary Nerve Repair: Anatomical Study and Case Series

In cases of isolated paralysis of the axillary nerve, dissection of the distal stump at the posterior deltoid border can be difficult because of scarring from an injury or previous surgery. To overcome this, we propose dissecting the anterior division of the axillary nerve (ADAN) using a deltoid-splitting approach. We investigated the anatomy of the ADAN as it pertains to the transdeltoid approach and report the clinical application of this approach in 9 patients with isolated axillary nerve injury. The axillary nerve and its branches were dissected in 9 fresh cadaver specimens. In the clinical series, 1 patient with a lesion confined to the ADAN underwent nerve grafting. In the remaining 8 patients, the ADAN was repaired by transferring the triceps lower medial head and anconeus (TLMA) motor branch via a single-incision or double-incision posterior arm approach. The posterior division of the axillary nerve does not travel around the humerus. It innervated the posterior deltoid and teres minor muscles. At the posterior margin of the humerus, the ADAN ran adjacent to the teres minor tendon. The ADAN's trajectory on the lateral side of the humerus was 65 mm (SD ± 8 mm) from the midpoint of the acromion. One centimeter from the origin, the ADAN offered a prominent branch to the middle deltoid and wound around the humerus anteriorly at the surgical neck just distal to the infraspinatus tendon. A transdeltoid approach was feasible in all our patients. The TLMA was reached without any tension in the ADAN. Middle deltoid strength in 1 patient who had received a graft scored M3, while anterior and middle deltoid strength in the remaining patients who underwent nerve transfers scored M4. With axillary nerve lesions, reinnervation of the ADAN is a priority. The transdeltoid approach between the posterior and middle deltoid offers a direct and feasible approach to the ADAN. Therapeutic V.

Is Anterior Plating Superior to the Bilateral Use of Retrograde Transpubic Screws for Treatment of Straddle Pelvic Ring Fractures? A Biomechanical Investigation.

Background: Fractures of the four anterior pubic rami are described as “straddle fractures”. The aim of this study was to compare biomechanical anterior plating (group 1) versus the bilateral use of retrograde transpubic screws (group 2). Methods: A straddle fracture was simulated in 16 artificial pelvises. All specimens were tested under progressively increasing cyclic loading, with monitoring by means of motion tracking. Results: Axial stiffness did not differ significantly between the groups, p = 0.88. Fracture displacement after 1000–4000 cycles was not significantly different between the groups, p ≥ 0.38; however, after 5000 cycles it was significantly less in the retrograde transpubic screw group compared to the anterior plating group, p = 0.04. No significantly different flexural rotations were detected between the groups, p ≥ 0.32. Moreover, no significant differences were detected between the groups with respect to their cycles to failure and failure loads, p = 0.14. Conclusion: The results of this biomechanical study reveal less fracture displacement in the retrograde transpubic screw group after long-term testing with no further significant difference between anterior plating and bilateral use of retrograde transpubic screws. While the open approach using anterior plating allows for better visualization of the fracture site and open reduction, the use of bilateral retrograde transpubic screws, splinting the fracture, presents a minimally invasive and biomechanically stable technique.