Brion Benninger

Anatomic basis to the ultrasound-guided approach for saphenous nerve blockade.

Background and Objectives: Successful blockade of the saphenous nerve using surface landmarks can be challenging. We evaluated the anatomic basis of performing a saphenous nerve block with ultrasound (US) using its relationship to the saphenous branch of descending genicular artery, sartorius muscle, and the adductor hiatus as defined by cadaveric measurements. Methods: Using a total of 9 cadaveric knee dissections, the saphenous nerve and its relationship to the saphenous branch of the descending genicular artery (SBDGA) were examined. The distances from the patella to the distal end of the adductor canal and the bifurcation of the saphenous nerve were recorded. US images of an above-the-knee, subsartorial saphenous nerve block were reviewed. Results: The saphenous nerve coursed with the SBDGA. It exited the adductor canal at a median of 10.25 cm (range, 7.0-11.5 cm) cephalad to the proximal patellar border and traveled closely with the SBDGA. At its bifurcation into the infrapatellar branch and sartorial branch, the saphenous nerve was at its closest approximation to the SBDGA. This point was found to be at a median of 2.7 cm (range, 2.1-3.4 cm) cephalad and a median of 6.6 cm (range, 5.0-9.0 cm) posterior to the proximal and posterior patellar border, respectively. Conclusions: The US-guided approach for saphenous nerve blockade using its close anatomic relationship to the SBDGA is a feasible alternative to previously described surface landmark-based or US-guided paravenous approaches.

The development of a core syllabus for the teaching of head and neck anatomy to medical students

The study of human anatomy has traditionally served as a fundamental component in the basic science education of medical students, yet there exists a remarkable lack of firm guidance on essential features that must be included in a gross anatomy course, which would constitute a “Core Syllabus” of absolutely mandatory structures and related clinical pathologies. While universal agreement on the details of a core syllabus is elusive, there is a general consensus that a core syllabus aims to identify the minimum level of knowledge expected of recently qualified medical graduates in order to carry out clinical procedures safely and effectively, while avoiding overloading students with unnecessary facts that have less immediate application to their future careers as clinicians. This paper aims to identify consensus standards of essential features of Head and Neck anatomy via a Delphi Panel consisting of anatomists and clinicians who evaluated syllabus content structures (greater than 1,000) as “essential”, “important”, “acceptable”, or “not required.” The goal is to provide guidance for program/course directors who intend to provide the optimal balance between establishing a comprehensive list of clinically relevant essential structures and an overwhelming litany, which would otherwise overburden trainees in their initial years of medical school with superficial rote learning, which potentially dilutes the key and enduring fundamental lessons that prepare students for training in any medical field. Clin. Anat. 27:321–330, 2014.

Clinical Measurements of Hard Palate and Implications for Subepithelial Connective Tissue Grafts With Suggestions for Palatal Nomenclature

PURPOSE The objectives of the present study were to 1) identify a reliable measuring technique for a palatal graft, 2) observe the patterns of the neurovascular bundle, and 3) identify the morphology of the hard palate. Subepithelial connective tissue grafts are performed at an increasing rate to improve esthetics and oral health. Palatal graft techniques began in 1963, and today the subepithelial connective tissue graft is the most widely accepted technique. The greater palatine nerve and artery are critical neurovascular structures to identify. Their pattern and palate morphology are not well defined. MATERIALS AND METHODS Anatomy texts, atlases, and specialty texts were analyzed. We dissected 17 palates (17 left and right halves) from embalmed human cadavers, implementing a measuring technique to locate the most coronal structure of the greater palatine artery and greater palatine nerve bundle, observing the patterns and palatal morphology. Electronic digital calipers and a periodontal probe were used for data collection. RESULTS The dissection results revealed a reliable measuring technique, a common pattern of the bundle, and osseous palatal landmarks not clearly defined in contemporary texts. The dissections also demonstrated a medial and lateral groove, along with a crest in the palatine process of the maxillary bone. The greater palatine artery traversed the lateral groove, and the greater palatine nerve traversed the medial groove consistently. The crest was located anteroposteriorly between the grooves. CONCLUSIONS The results of our study suggest a useful measurement technique, a consistent neurovascular pattern, and the need to reconsider the palatal nomenclature.

Assessing Validity of Actual Tooth Height and Width From Cone Beam Images of Cadavers With Subsequent Dissection to Aid Oral Surgery

PURPOSE Cone-beam computed technology (CBCT) is a relatively new medium for maxillofacial conditions. Developed in 1998, commercial cone beam technology has been commonly used since 2000. CBCT offers less radiation than computed tomography (CT) in 3D image construction. With the meteoric rise in the number of dental implant surgeries, CBCT could become a common machine in dental offices. The objective of this study is to validate the accuracy of CBCT tooth measurements. MATERIALS Twelve embalmed cadavers had a complete CBCT of the head and neck region. Ninety-six teeth (8 per cadaver) were extracted in total, but only 69 were collected and measured. CEN-TECH electronic calipers were used to measure the extracted teeth. iCAT measurements were used for imaged teeth. METHODS A literature search was conducted on the validity and use of CBCT regarding tooth measurements for implant surgery. Extracted teeth were measured in the vertical, facial to lingual, and mesial to distal dimensions. Exclusion factors included crown or root fracture damage during extraction. RESULTS A literature search revealed studies that validated bone measurements using 14 different location points on the maxilla and 17 anatomical landmarks on the skull. Both studies validated bone measurements on CBCT. However, no studies were identified measuring teeth lengths for implant surgery. Three, two-tailed, paired t-test compared the iCAT image measurements to the extracted teeth measurements for each dimension. There was no statistical significance for each dimension. CONCLUSION This study suggests using iCAT measurements on teeth from CBCT imaging would reflect the actual tooth length and could be beneficial for implant surgery.

Analysis of the uncinate processes of the cervical spine: an anatomical study.

OBJECT Although the uncovertebral region is neurosurgically relevant, relatively little is reported in the literature, specifically the neurosurgical literature, regarding its anatomy. Therefore, the present study aimed at further elucidation of this regions morphological features. METHODS Morphometry was performed on the uncinate processes of 40 adult human skeletons. Additionally, range of motion testing was performed, with special attention given to the uncinate processes. Finally, these excrescences were classified based on their encroachment on the adjacent intervertebral foramen. RESULTS The height of these processes was on average 4.8 mm, and there was an inverse relationship between height of the uncinate process and the size of the intervertebral foramen. Degeneration of the vertebral body (VB) did not correlate with whether the uncinate process effaced the intervertebral foramen. The taller uncinate processes tended to be located below C-3 vertebral levels, and their average anteroposterior length was 8 mm. The average thickness was found to be 4.9 mm for the base and 1.8 mm for the apex. There were no significant differences found between vertebral level and thickness of the uncinate process. Arthritic changes of the cervical VBs did not necessarily deform the uncinate processes. With axial rotation, the intervertebral discs were noted to be driven into the ipsilateral uncinate process. With lateral flexion, the ipsilateral uncinate processes aided the ipsilateral facet joints in maintaining the integrity of the ipsilateral intervertebral foramen. CONCLUSIONS A good appreciation for the anatomy of the uncinate processes is important to the neurosurgeon who operates on the spine. It is hoped that the data presented herein will decrease complications during surgical approaches to the cervical spine.

Integrating ultrasound into modern medical curricula

Ultrasonography is widely practiced in many disciplines. It is becoming increasingly important to design well‐structured curricula to introduce imaging to students during medical school. This review aims to analyze the literature for evidence of how ultrasonography has been incorporated into anatomy education in medical school curricula worldwide. A literature search was conducted using multiple databases with the keywords: “Ultrasound OR Ultrasonographic examination*” and “Medical student* OR Undergraduate teaching* OR Medical education*” and “Anatomy* OR Living anatomy* OR Real‐time anatomy.*” This review found that ultrasound curricula vary in stage of implementation, course length, number of sessions offered to students as well as staffing and additional course components. Most courses consisted of didactic lectures supplemented with demonstration sessions and/or hands‐on ultrasound scanning sessions. The stage of course implementation tended to depend on the aim of the course; introductory courses were offered earlier in a students career. Most courses improved student confidence and exam performance, and more junior students tended to benefit more from learning anatomy with ultrasound guidance rather than learning clinical examination skills. Students tended to prefer smaller groups when learning ultrasound to get more access to using the machines themselves. Ultrasonography is an important skill, which should be taught to medical students early in their careers as it facilitates anatomical education and is clinically relevant, though further objective research required to support the use of ultrasound education as a tool to improve clinical examination skills in medical students. Clin. Anat. 30:452–460, 2017.

Approaches to Proximal Tibial Bone Harvest Techniques

ABSTRACT Objectives The iliac crest is the standard site for harvesting bone; however, this procedure may require another specialist and a general anaesthetic. The proximal tibial bone harvest has gained popularity for harvesting autogenous bone. An analysis of the clinical literature regarding the various regions for harvesting bone demonstrates that the use of the proximal tibia led to shorter hospital stays, lower morbidity rates, and a shorter learning curve for the surgeon. The purpose of this study was to analyze the clinical anatomy of a proximal tibial bone harvest graft to provide the anatomical architecture supporting a safe procedure. Materials and Methods Dissection of 58 lower limbs from embalmed cadavers was conducted to determine the anatomy of a proximal tibial bone harvest (PTBH). Results Dissection revealed that the medial approach has fewer clinically relevant neurovascular structures in harms way, and a larger surface area, providing the clinician a confident surgical window to perform the procedure. Conclusions The anatomical basis of this study suggests that the medial proximal tibial bone harvest approach would have fewer serious structures in harms way compared to the lateral; however, the lateral approach may be preferred for a subgroup of patients.

The Importance of the Saphenous Nerve in Ankle Surgery.

BACKGROUND:Recent evidence suggests that the saphenous nerve may be involved in the innervation of deeper structures at the medial ankle. In this study, we sought to determine the consistency and variability of the saphenous nerve innervation at the distal tibia and medial ankle joint capsule. METHODS:One hundred three lower extremities from 52 embalmed cadavers were dissected to identify the deep branches of saphenous nerve along its distal course. RESULTS:In all specimens, the saphenous nerve had branches, emerging between 3.9 and 8.2 cm above the medial malleolus, to the periosteum of the distal tibia and the medial capsule of the ankle joint. CONCLUSIONS:Deep branches of the saphenous nerve innervate the periosteum of the distal tibia and talocrural capsule.

Meckel's diverticulum complicated by axial torsion and gangrene

Meckels diverticulum is a remnant of the omphalomesenteric duct and is the most common congenital anomalies of the gastrointestinal tract. It has been known to mimic different disease states making its diagnosis difficult. Common complications consist of bleeding, intestinal obstruction and inflammation. The patient discussed in this case study was a 29-year-old Hispanic female who presented with right lower quadrant abdominal pain. A CT scan showed a normal appendix, thickened terminal ileum and a high-grade distal small bowel obstruction with a possible closed-loop obstruction. Laparoscopy revealed Meckels diverticulum with the rare complication of torsion. The mechanism of torsion has been postulated but with little evidence. The purpose of this case report is to discuss the apparent mechanism of axial torsion secondary to the presence of a mesodiverticular band, provide visual evidence at surgery and recommend all Meckels diverticulum associated with a mesodiverticular band be resected to prevent further complications.

The nerve of McKenzie: Anatomic study with application to intradural rhizotomy for spasmodic torticollis

Abstract Introduction. Medically recalcitrant spasmodic torticollis may necessitate surgical intervention. One procedure used for this pathologic entity is intradural rhizotomy. However, some patients are symptomatic, perhaps due to an overlooked or underappreciated nerve of McKenzie. The authors’ goal was to further elucidate the anatomy of this nerve of the craniocervical junction. Materials and methods. Fifteen adult cadavers (30 sides) underwent microsurgical dissection and observations of the nerve of McKenzie. Morphometrics were performed and anatomic relationships were documented under surgical magnification. Results. The nerve of McKenzie was found on 70% of sides and was always a single branch. Average length was 5.2 mm for left sides and 6 mm for right sides. Average diameter was 0.9 mm (0.5–1.2 mm). In two specimens, the nerve was found bilaterally. It pierced the first denticulate ligament on 11 sides (52.4%) and travelled through its two prongs on three sides (14.3%) to connect to the anteriorly placed C1 ventral root. On five sides, it was in intimate contact with the adventitia of the vertebral artery. It was more common on right sides and in males, and this was statistically significant. Conclusions. The authors identified the nerve of McKenzie in most specimens. This nerve, if overlooked during surgical treatment of spasmodic torticollis, may result in continued symptoms. The nerve of McKenzie was often concealed within the denticulate ligament or adventitia of the vertebral artery. The authors hope the data presented here will aid neurosurgeons and decrease complications in patients who undergo neurotomy for spasmodic torticollis.