Success Rate in Puncture of the Temporomandibular Joint.

Puncture of the temporomandibular joint (TMJ) is a minimally invasive treatment for various jaw disorders. This study used a cadaveric model to evaluate the procedure from two entrance points with respect to hit ratio and possible complications, such as extraarticular extrusion of injection fluid. Ten heads, embalmed with Thiel's method, were investigated. A straight line drawn with a colored pen connected the center of the tragus and the lateral canthus. The first portal "A" was located at a distance of 1 cm anterior and 2 mm caudal from the center of the tragus. Portal "B" was located 2 cm anterior and 1 cm caudal starting from the same reference point. Punctures "A" and "B" were performed alternately on the right and left sides. Specimens were dissected and the local distribution of the injected latex was recorded. With Approach A, four punctures (40%; 4/10) reached the TMJ, whereas with Approach B, six injections (60%; 6/10) entered the TMJ. There were no statistically significant differences between the tested puncture methods (P = 0.0317) and body sides (P = 1). With each method, for example, 35% (7/20) each, the injected latex was either periarticular or retromandibular. In a further 20% (4/20), it was located subperiosteally alongside the ramus of mandible. The latex was injected into the infratemporal fossa and the external acoustic meatus in one case each (each 5%). There was no statistically significant difference between the techniques. The adjacent anatomy has to be kept in mind during TMJ puncture as the complication rate was remarkably high, suggesting that ultrasound guided intraarticular injection could improve the hit rate. Clin. Anat., 33:683-688, 2020. © 2019 Wiley Periodicals, Inc.

The Important Relationship Between the Radial Artery's Course and the Radius during Henry's Anterior Forearm Surgical Exposure.

The aim of this study was to investigate the intersection point of the radial artery (RA) with Henry's approach. Ninety forearms from adult human cadavers which had been embalmed using Thiel's method underwent dissection. Henry's approach was performed alongside the whole length of the forearm, and the RAs course was investigated. Its crossing point with the approach was identified, and the distance from this point to the radial styloid process was determined. In addition, the total radial length (RL) was measured from the radial styloid process to the proximal margin of the radial head. The former measurements were analyzed as proportions with regard to the total RLs. Concerning right radii, the intersection point was, on average, at a proportion of 56.2% of the radius, starting from the tip of the radial styloid process. In left radii, this was located at a mean proportion of 61.2%. In cases of multiply fractured radii, care must be taken at the interval between 40% and 80% to avoid RA lesions during dissection from distal to proximal. Clin. Anat., 33:983-987, 2020. © 2019 Wiley Periodicals, Inc.

Safe zone for the posterior interosseous nerve with regard to the lateral and posterior approaches to the proximal radius.

PURPOSE: The posterior interosseous nerve (PIN) is at risk during the posterior and lateral approaches to the proximal radius. We aimed to define a safe zone for these approaches to avoid injury of the PIN and to evaluate their close and changing relationship to the nerve during forearm rotation. METHODS: The study collective consisted of 50 upper limbs. After performance of the lateral approach, the distance between the tip of the radial head and the PIN's exit point from the supinator (= distance 1) and the shortest interval between the nerve's exit to the radial margin of the ulna (= distance 2) were measured in maximum pronation and supination. Then, the dorsal approach was conducted and again distance 1 and the interval between the distal margin of the anconeus and the nerve's exit point (distance 2) were evaluated (pronation and supination). RESULTS: There were significantly shorter distances during supination in comparison to pronation. Regarding the lateral approach, distance 1 changed from a mean of 60.3 mm (supination) to 62.7 mm in pronation (p < 0.001). For the dorsal approach, distance 1 decreased significantly (p < 0.001) from 62.9 mm (pronation) to 60.2 mm (supination). CONCLUSION: Supination during the lateral and dorsal approaches to the proximal radius needs to be avoided to protect the PIN. Furthermore, the nerve appeared at an interval between 45 and 84.1 mm (lateral approach) and 47.5-93.8 mm (dorsal approach), respectively. Therefore, care must be taken at this height during extension of the approaches in a distal direction.

Minimally invasive plate osteosynthesis of the humeral shaft with regard to adjacent anatomical characteristics.

The study goal was to evaluate the distances from the radial (RN), the musculocutaneous (MN) and axillary nerves (AN) and the medial neurovascular bundle of the upper arm to a minimally invasive applied plate and to define its relation to the RN during different degrees of malrotation during MIPO. The sample involved ten upper extremities. Application of a PHILOS plate was performed through a Delta-split. Intervals between the AN, MN, RN and the medial vascular bundle were defined at various positions. The humeral shaft was artificially fractured at a height of about the mean of the plate. The distal fragment was brought into 15° and 30° internal (IR) as well as external rotation (ER) and here, the plate's relation to the RN was evaluated. The medial neurovascular bundle intersected the plate at its distal part in two specimens. Regarding the distances from the RN to the plate during different rotation positions the distances became significantly longer during ER, respectively shorter during IR. The medial neurovascular bundle and the RN were identified as the main structures at risk. Care must be taken during distal screw placement and malrotation exceeding 15° must be avoided during MIPO.

Projection of the A1-Pulley of the Thumb onto Superficial Anatomical Landmarks: An Anatomical Study and a Useful Guide to Surgeons.

BACKGROUND: The aim of our study was to project the A1-pulley of the thumb onto the total thumb length to enable its complete division with and without direct sight. MATERIALS AND METHODS: The study involved 50 hands from adult human cadavers. The proximal and distal borders of the A1-pulley were measured with reference to the first metacarpophalangeal joint (MCPJ). The length of the thumb was defined as the interval between the first carpometacarpal joint (CMCJ) and the apex of the thumb. The length of the pulley is calculated proportionally with reference to the line between the first CMCJ and apex of the thumb. RESULTS: Approximated by computing 95% confidence intervals, the pulley can be expected to lie in an area between 34.0% (proximal border) and 57.8% (distal border) alongside this line. CONCLUSION: Percutaneous and minimally-invasive division of the A1-pulley needs to be performed between 34.0 and 57.8% of the length between the first CMCJ and apex of the thumb.

Morphology of the Posterior Interosseous Nerve with Regard to Entrapment Syndrome.

BACKGROUND: Posterior interosseous nerve (PIN) entrapment syndrome is a rare condition and is predisposed by anatomical factors such as narrow passages through fibrous arcades; whereas, the Arcade of Frohse (AF) is the most common entrapment point. The aim of this study was to evaluate the entrance and exit points of the PIN into the supinator in detail. MATERIALS AND METHODS: One hundred unpaired upper extremities underwent dissection. The PIN's entrance and exit points from the supinator were depicted. The distances between the tip of the radial head (RH) and the AF and the exit point of the PIN from the supinator were measured. Further, it was checked if the borders of the AF and the exit point were muscular, tendinous or a combination of these. RESULTS: The interval between the PIN's entry into the supinator and the tip of the RH was at a mean of 28.9 mm. Concerning the border of the AF, in 54 cases a muscular and in 46 specimens a tendinous version could be observed. The interval between the exit point of the PIN and the tip of the RH proved to be at a mean of 64.2 mm. Further, the exit's border was muscular in 65 specimens and tendinous in 35 cases. CONCLUSION: During surgical treatment of the PIN syndrome, it needs to be kept in mind that approximately one-third of all patients might also suffer from entrapment at the exit point of the PIN.

Prevalence of the distal oblique bundle of the interosseous membrane of the forearm: an anatomical study.

A study was undertaken to examine the presence of the distal oblique bundle of the forearm in a large sample in order to describe its true prevalence. The study sample consisted of 200 cadaveric forearms. Fifteen were excluded due to defects in the distal interosseous membrane. In the remaining 185 specimens, the distal interosseous membrane was examined following removal of soft tissue, to determine whether a distal oblique bundle was present and whether there were connecting fibres to the distal radio-ulnar joint. The distal oblique bundle was observed in 53 specimens (29%). In 45 of these forearms (85%), one or more connecting fibres to the distal radio-ulnar joint were identified. The presence of a distal oblique bundle in 29% is less frequent than that reported in previous literature. The presence of the distal oblique bundle should be noted and may be of importance in the management of disorders of the distal radio-ulnar joint.