Percutaneous ultrasound-guided versus open cut-down access to femoral vessels for the placement of a REBOA catheter.

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) may be useful in treating exsanguinating trauma patients. This study seeks to compare rates of success, complications and time required for vascular access between ultrasound-guidance and surgical cut-down for femoral sheath insertion as a prospective observational case control study. Participating clinicians from either trauma surgery or anesthesiology were allocated to surgical cut-down or percutaneous ultrasound-guided puncture on a 1:1 ratio. Time spans to vessel identification, successful puncture, and balloon inflation were recorded. 80 study participants were recruited and allocated to 40 open cut-down approaches and 40 percutaneous ultrasound-guided approaches. REBOA catheter placement was successful in 18/40 cases (45%) using a percutaneous ultrasound guided technique and 33/40 times (83%) using the open cut-down approach (p < 0.001). Median times [in seconds] compared between percutaneous ultrasound-guided puncture and surgical cut-down were 36 (18-73) versus 117(56-213) for vessel visualization (p < 0.001), 136 (97-175) versus 183 (156-219) for vessel puncture (p < 0.001), and 375 (240-600) versus 288 (244-379) for balloon inflation (p = 0.08) overall. Access to femoral vessels for REBOA catheter placement is safer when performed by cut-down and direct visualization but can be performed faster by an ultrasound-guided technique when vessels can be identified clearly and rapidly.

Emergency approach to the femoral artery.

PURPOSE: The purpose of this study was to evaluate the applicability and potentially associated harms of emergency access to the femoral artery and vein in a sample of physicians working together in the emergency department of a level I trauma center. In addition, to investigate whether there are differences between participants in terms of different levels of training. METHODS: A sample of 36 orthopedic trauma and anesthesiology assistant doctors, specialists, and senior physician was recruited from the emergency room management at a level I trauma center in Graz, Austria. Emergency approach to the femoral vessels was performed on 33 fresh cadavers. Attention was paid to time, successful clamping of the vessels, self-assessment and learning curve. RESULTS: The approach was performed correctly in 97.2% (35/36) of all cases. 97.2% of all participants (35/36) were confident to perform the emergency access. They were proven right, since especially the resident and senior subgroups achieved satisfactory results concerning the correct performance of the approach to the femoral vessels as well as correct identification of the femoral artery and vein. CONCLUSION: In conclusion, we evaluated the emergency access to the femoral artery (FA) and femoral vein (FV) as an easily teachable procedure including high success rates (correct performance in 97.2%).

Proportional localisation of the entry point of the coracobrachialis muscle by the musculocutaneous nerve along the humerus.

PURPOSE: To project the distance between the tip of the greater tubercle (GT), respectively, the proximal border of the tip of the coracoid process (CP) and the entry point of the coracobrachialis by the musculocutaneous nerve (MCN) proportionally onto the humeral length. METHODS: Sixty-six upper extremities were included in the study. The distance between the tip of the GT and the distal tip of the lateral humeral epicondyle (LE) was evaluated as the humeral length (HL). The interval between the tip of the GT and the entry point of the coracobrachialis muscle by the MCN was measured. The distance between the proximal border of the tip of the CP and the distal portion of the medial humeral epicondyle (ME) and the entry point of the MCN into the coracobrachialis were evaluated. Proportions were used to project the entry point of the coracobrachialis by the MCN along the HL, respectively, the interval between the proximal border of the tip of the CP and the distal tip of the ME. RESULTS: The entry point of the MCN into the coracobrachialis muscle can be expected at an interval between 14.9 and 33.9% of the HL (between the tip of the GT and the LE), starting from the tip of the GT. Regarding the reference line between the proximal border of the CP and the ME, the nerve's entry point was located between 14.2 and 34.4%, starting from the CP. CONCLUSION: Results represent easily applicable intervals for intraoperative localisation of the MCN.

Dorsal minimally invasive plate osteosynthesis of the humerus: Feasibility and risk of nervous injury of a modified technique in an anatomical study.

BACKGROUND: The aim of the study was to design a convenient technique for dorsal minimally invasive plate osteosynthesis (MIPO) of extra-articular fractures of both distal thirds of the humeral shaft as well as to characterise the course and proximity of the radial nerve (RN) and the axillary nerve (AN). METHODS: The collective consisted of 20 upper extremities of human adult body donors. A 3.5 mm Locking Compression Plate (LCP), an extra-articular distal humerus plate was inserted through a MIPO approach including two incisions. The primary incision was performed 5 cm in lenght on the dorsal side of the lateral epicondyle. An additional 5 cm incision was conducted distal to the humeral deltoid muscle insertion and the RN was depicted. The longest suitable plate was advanced under nerve protection starting distally and fixed by locking screws. A third incision with a length of 5 cm was made beginning at the distal border of the deltoid muscle, and a muscle split was performed to dissect the AN. The respective plate holes, where the AN and RN were located and the distances between the nerves were examined. RESULTS: The RN was mostly (30%) localised on holes 6 and 7 (starting distally). The AN laid directly on the plate in 65% and on the most proximal plate hole in 12 cases, but was never situated underneath the plate. The distance between the AN and RN was at mean 93.5 mm. CONCLUSIONS: MIPO via a dorsal method proves to be a noteworthy technique and valuable option as indicated by our results. This 5-5-(5) concept may be performed as a two-incision or three-incision technique for extra-articular fractures of both distal thirds of the humerus.

Anatomic-Topographic Investigation of the Branches of the Dorsal Ramus of Thoracic Spinal Nerves.

INTRODUCTION: Percutaneous radiofrequency facet denervation (PRFD) by thermocoagulation is a useful treatment for nonspecific thoracic pain syndrome. To guarantee that maximal thermal lesion is applied to the nerve, it is essential to have precise knowledge of the topography of the thoracic dorsal branches of the spinal nerves. This special anatomy was investigated, and the results were compared with the existing technique for PRFD, where the active needle tip is placed in the junction of the superior articular process and the transverse process. METHODS: Twenty thoracic spines of cadavers (10 females and 10 males) embalmed according to Thiel's method were bilaterally dissected. After careful removal of skin and subcutaneous fat tissue, the lateral and medial branches were traced centrally. In addition, the articular branch to the thoracic facet joint was traced peripherally. The distance of the medial branch to the inferior articular process at the level of the nerve passing the superior costotransverse ligament was measured. RESULTS: The dorsal branch bifurcates into lateral and medial branches medial to the superior costotransverse ligament. The medial branch runs laterally first to pass in between two parts of the intertransverse ligament running dorsally and to turn medially superficial to this ligament. The zygapophysial branch always originated from the medial branch passing the inferior articular process laterally by running caudally to turn medially and send branches to the capsule of the zygapophyseal joint. The distance of the medial branch lateral to the inferior articular process was constantly 3 mm. CONCLUSIONS: The current technique of PRFD at the thoracic spine targets the medial branch distal to the separation of the articular branch, rendering the lesion ineffective at denervating the zygapophyseal joint. For selective thermocoagulation of the articular branches of the thoracic zygapophyseal joint, a new technique should be developed. We propose an anatomically informed needle position that can now be confirmed clinically.

Anatomical Topographical Investigation of the Medial Branch of the Dorsal Thoracic Branch of the Spinal Nerve in the Segments T10-T12.

INTRODUCTION: The zygapophyseal joints represent one possible cause for back pain. Therefore, many interventions are targeting the denervation of the facet joints. The aim of this study is to describe the course of the medial branch of the dorsal branch of the spinal nerve and its articular branches to the zygapophyseal joints in the segments T10-T12. METHODS: The medial branches in the thoracic segments T10-T12 were dissected in 20 Thiel embalmed cadavers. An Eschenbach magnifying glass (4.0× magnification) was used during dissection preserving the articular branches. The topography and the branching pattern of the medial branches was observed. RESULTS: The course of the nerves in the segments T10-T12 differed from each other because of the different osseous anatomy of each segment. The medial branch at the segment T10 crossed the tip of the transverse process in 28 of the 40 hemivertebral specimens. In the remaining cases it passed superior to the transverse process. At T11 the medial branch ran constantly through an osteofibrous canal. At the segment T12 the medial branches showed a similar course to the medial branches in the lumbar region. In many cases two articular branches, which arose from the medial branch were identified. CONCLUSIONS: The results of this study show a considerable anatomic variety at the segment T10. It also demonstrates that the transverse process is an important landmark to encounter the medial branch. Furthermore, the possibility of a double innervation of the facet joints should always be considered.

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.

Danger zone - The spermatic cord during anterior plating of the symphysis pubis.

BACKGROUND: Distances between anatomic landmarks and anatomic structures at risk are often underestimated by surgeons. PURPOSE: The goal of the study was to evaluate the distances between anatomic landmarks and the spermatic cord in case of anterior plating of the symphysis. METHODS: A total of 25 pelves (50 hemipelves) of male embalmed cadavers were dissected. A 5-hole 3.5mm locking compression plate (Synthes GmbH) was fixed from directly anterior on the symphysis. Measurements were taken 1) distance between the tips of both pubic tubercles, 2) horizontal interval between the lateral border of the plate and the medial margin of the SC (bilateral), 3) distances between the medial border of the SC and the tip of the pubic tubercle (bilateral), 4) distances between the medial border of the SC and the lateral basis of the pubic tubercle (bilateral). RESULTS: The distance between the pubic tubercles was 60.3mm in average (SD: 5.7). The interval between the lateral border of the plate and the medial margin of the SC was on average 4.5mm (SD: 1.9) on the right and 4.7mm (SD: 2.6) on the left side. The distance between the tip of the pubic tubercle and the medial border of the SC was in average 11.2mm (SD: 2.7) on the right, and 11.0mm (SD: 2.7) on the left side. The average distance between the medial border of the SC and the lateral basis of the pubic tubercle was 8.1mm (SD: 2.4) on the right and 8.2 mm (SD: 2.4) on the left side. CONCLUSION: The SC is at risk not only during dissection but also during anterior plating of the symphysis, because of its close relation to the SC. CLINICAL RELEVANCE: Average distances between the palpable pubic tubercle and the SC are below one finger breadth (as reference).

Evaluation of a New Virtual Reality Concept Teaching K-Wire Drilling With Force Feedback Simulated Haptic in Orthopedic Skills Training.

PURPOSE: Surgical simulations are becoming increasingly relevant in musculoskeletal training. They provide the opportunity to develop surgical skills in a controlled environment while reducing the risks for patients. For K-wire internal fixation in musculoskeletal surgery, a force feedback virtual reality (VR) simulator was developed. The aim of this study was to evaluate training results using this technology and compare the results with that of standard teaching on cadavers. METHODS: Twenty participants attending an AO Trauma Course during 2020 were randomly allocated in 2 groups. On day 1, group A was trained by senior surgeons using a cadaver and group B was trained by the VR simulator for K-wire insertion in the distal radius. On day 2, all participants performed K-wire insertion on the cadaver model, without assistance, to validate the training effect. RESULTS: On a surgical skills test, group B performed better than group A. In group B, the entry point of the first K-wire was closer to the targeted styloid process of the radius, and the protrusion of the K-wires into soft tissue was less than that in group A. CONCLUSIONS: Training with the VR simulator for K-wire insertion resulted in better surgical skills than training by a surgeon and cadaver model. CLINICAL RELEVANCE: Training with the VR simulator provides the opportunity to improve and refine surgical skills without the risk of harming patients. It offers easier access, unlimited repetitions, and is more cost-effective compared with training sessions with cadavers.

Relation of the lumbosacral trunk to the sacro-iliac joint.

This study aims to evaluate the relation between the lumbosacral trunk (LT) and the sacro-iliac joint (SIJ). In forty anatomic specimens (hemipelves) a classical antero-lateral approach to the SIJ was performed. The SIJ was marked at the linea terminalis (reference point A). Reference point B was situated at the upper edge of the interosseous sacro-iliac ligament. The length of the SIJ (distance A to B) and the distance between point A and the ventral branch of the fourth (L4) and fifth (L5) lumbar spinal nerves at the linea terminalis were measured. The SIJ had a mean length of 58.0 mm. The ventral branch of L5 was located closer to the SIJ in very long SIJs (mean length: ≥ 6.5 cm; mean distance: 9.8 mm) compared to very short joints (≤ 5 mm; mean distance: 11.3 mm). For the ventral branch of L4, very long SIJs had a mean distance of 7 mm and very short joints an average distance of 9.7 mm between point A and the nerve branch. A safe zone of approximately 1 cm to 2 cm (anterior to posterior) is present on the sacral surface (lateral to medial) for safe fixation of plates during anterior plate stabilization of the SIJ. Pelves with a shorter dorsoventral diameter of the most superior part of the SIJ apparently give more space for inserting plates.

Definition of a Risk Zone for the Axillary Nerve Based on Superficial Landmarks.

BACKGROUND: The aim of this study was to investigate the axillary nerve's location along superficial anatomical landmarks, and to define a convenient risk zone. METHODS: A total of 123 upper extremities were evaluated. After dissection of the axillary nerve, the vertical distance between the upper border of the anterolateral edge of the acromion and the proximal border of the nerve was measured. Furthermore, the interval between the proximal border and the distal border of the axillary nerve's branches was evaluated. The interval between the distal border of the branches and the most distal part of the lateral humeral epicondyle was measured. The distance between the anterolateral edge of the acromion and the lateral humeral epicondyle was evaluated. Measurements were expressed as proportions with respect to the distance between the acromion and the lateral humeral epicondyle. RESULTS: The distance between the acromion and the proximal border of the axillary nerve's branches was at a height of 10 percent of the distance between the acromion and the lateral humeral epicondyle, starting from the acromion (90 percent when starting from the lateral humeral epicondyle). The interval between the proximal and distal margins of the axillary nerve's branches was between 10 percent and 30 to 35 percent of this interval, starting from the acromion (65 to 70 percent when starting from the lateral humeral epicondyle). CONCLUSIONS: The authors were able to locate the branches of the axillary nerve at an interval between 10 and 35 percent of the distance between the acromion and the lateral humeral epicondyle, starting from the acromion. This makes the proximal third of this distance an easily applicable risk zone during shoulder surgery.

Screw placement in two different implants for proximal humeral fractures regarding regional differences in bone mineral density: An anatomical study.

BACKGROUND: The aim of this study was to investigate proximal humerus plating regarding drill depth and over penetration of the glenohumeral joint and to find a relation between these findings and different areas of bone mineral density (BMD) in the humeral head. MATERIAL & METHODS: The study sample involved 45 upper extremities from human adult cadavers. Two different plates (HOFER; PHILOS) were applied to the proximal humerus. Each hole was drilled until the respective participant thought to have placed the drill bit subchondral. Next, penetration of the far cortex was conducted to determine the residual bone stock. Additionally, the point of screw penetration of the far cortex was identified for each hole of the plates and allocated to five regions with different bone mineral density as described by Tingart et al. RESULTS: The screw penetration rate and the residual bone stock were compared within the 5 BMD regions. A significantly thicker residual bone stock was found at the central region (SD ± 13.1 mm) than in the anterior region (SD ± 9.5 mm) and in the posterior region (SD ± 8.5 mm). The anterior region revealed a significantly higher penetration rate than the posterior region (p = 0.01) and the central region (p = 0.03). CONCLUSION: The anterior region of the humeral head was associated with a higher over penetration rate of the far cortex into the glenohumeral joint and a decreased bone stock after subchondral drilling representing a reduced bone mineral density (BMD). LEVEL OF EVIDENCE: Cadaver Study.

Evaluation of screw placement in proximal humerus fractures regarding drilling manoeuvre and surgeon's experience.

INTRODUCTION: Following proximal humeral plate osteosynthesis, mechanical complication rates ranging up to 40% have been reported. The study aims to determine the influence of surgeons' experience and the technique of drilling on the complication rate. MATERIALS AND METHODS: The sample involved 45 cadaveric humeri. Six orthopaedic surgeons were divided into two groups with regard to their level of experience (novice versus expert group). On each humerus two different proximal humerus plates were applied. Drillings were performed either with a sharp or worn drill bit (to simulate either sharp or blunt drilling). The respective holes were drilled until the respective participant thought to have placed the drill bit subchondrally, followed by perforation of the cartilage of the humeral head. Both these values and cases of unintended penetration of the articular cavity were evaluated. RESULTS: Fourteen holes (3.6%) were primary penetrated in the joint cavity in the worn-drill-bit-subgroup and 19 holes (5%) in the sharp-drill-bit-group. The latter had an average distance between the chosen subchondral position and the humeral articular surface of 8.3 mm and the worn-drill-bit-subgroup was at 10.6 mm. In the novice group 20 perforations (5.2%) of the joint space occurred and the mean interval between the chosen subchondral point and the humeral articular surface was 4.0 mm. The experienced surgeons showed a perforation rate of 3.4% and were at a mean of 14.9 mm. There were no significant differences regarding drilling manoeuvres and experience. CONCLUSION: Although our results are satisfactory, they can be traced back to the relatively high interval between the respective chosen position of the drill bit and the humeral articular surface which may not guarantee screw stability during ORIF of all fracture patterns.

The articular branch of the peroneal nerve to the proximal tibiofibular joint descends at a mean height of approximately 18 mm distal to the postero-lateral tip of the fibular head.

PURPOSE: The aim of the study was to evaluate the anatomical details of the articular branch of the peroneal nerve to the proximal tibiofibular joint and to project the height of its descent in relation to the fibular length. METHODS: Twenty-five lower extremities were included in the study. Following identification of the common peroneal nerve, its course was traced to its division into the deep and superficial peroneal nerve. The articular branch was identified. The postero-lateral tip of the fibular head was marked and the interval from this landmark to the diversion of the articular branch was measured. The length of the fibula, as the interval between the postero-lateral tip of the fibular head and the tip of the lateral malleolus, was evaluated. The quotient of descending point of the articular branch in relation to the individual fibular length was calculated. RESULTS: The articular branch descended either from the common peroneal nerve or the deep peroneal nerve. The descending point was located at a mean height of 18.1 mm distal to the postero-lateral tip of the fibular head. Concerning the relation to the fibular length, this was at a mean of 5.1%, starting from the same reference point. CONCLUSION: The articular branch of the common peroneal nerve was located at a mean height of 18.1 mm distal to the the postero-lateral tip of the fibular head, respectively, at a mean of 5.1% of the whole fibular length starting from the same reference point. These details represent a convenient orientation during surgical treatment of intraneural ganglia of the common peroneal nerve, which may result directly from knee trauma and indirectly from ankle sprain.

An anatomical study of transpedicular vs. extrapedicular approach for kyphoplasty and vertebroplasty in the thoracic spine.

INTRODUCTION: Percutaneous vertebral augmentation is a common therapeutic approach for osteoporotic or osteolytic vertebral fractures. Due to the variable pedicle anatomy two different approaches, the transpedicular and the extrapedicular approach have been established. In particular, in the middle and upper thoracic spine, percutaneous procedures are challenging because of difficult visualisation of anatomical landmarks and a more unfavourable anatomy with smaller and differently orientated pedicles. MATERIAL AND METHODS: In our cadaveric study we compared the transpedicular and the extrapedicular approach to the thoracic spine. In 26 cadaveric spine specimes, embalmed using Thiel's method, we placed a total of 486 trans- and extrapedicular K-wires through Jamshidi needles in the vertebral bodies T4 - T12 under fluoroscopy. A CT scan was then performed to verify the actual position of the K-wire. Malpositioning was defined as deviation from the planned approach or placement of the K-wire in the spinal canal or outside the vertebral body. Number and direction of malpositionings was recorded. RESULTS: Malpositioning occurred in 68 of 468 K-wires. It was more frequent in the transpedicular (54) than in the extrapedicular (14) approach. Intraspinal malposition was seen more often in the transpedicular approach (n=36) especially in the upper and middle thoracic spine. CONCLUSION: In summary both approaches are relatively safe but in the upper and middle thoracic spine the risk of intraspinal malpositioning seems to be lower when using the extrapedicular approach.

Minimally Invasive Lower Leg Fasciotomy for Chronic Exertional Compartment Syndrome-How Safe Is It? A Cadaveric Study.

BACKGROUND: Chronic exertional compartment syndrome (CECS) is a recognized clinical diagnosis in running athletes and military recruits. Minimally invasive fasciotomy techniques have become increasingly popular, but with varied results and small case numbers. Although decompression of the anterior and peroneal compartments has demonstrated a low rate of iatrogenic injury, little is known about the safety of decompressing the deep posterior compartment. PURPOSE: To evaluate the risk of iatrogenic injury when using minimally invasive techniques to decompress the anterior, peroneal, and deep posterior compartments of the lower leg. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 60 lower extremities from 30 adult cadavers were subject to fasciotomy of the anterior, peroneal, and deep posterior compartments using a minimally invasive technique. Two common variations in surgical technique were employed to decompress each compartment. Anatomical dissection was subsequently carried out to identify incomplete division of the fascia, muscle injury, neurovascular injury, and the anatomical relationship of key neurovascular structures to the incisions. RESULTS: Release of the anterior and peroneal compartments was successful in all but 2 specimens. There was no injury to the superficial peroneal nerve or any vessel in any specimen. A transverse incision crossing the anterior intermuscular septum resulted in muscle injury in 20% of the cases. Release of the deep posterior compartment was successful in all but 1 specimen when a longitudinal skin incision was used, without injury to neurovascular structures. Compared with a longitudinal incision, a transverse skin incision resulted in fewer complete releases of the deep posterior compartment and a significantly higher rate of injury to the saphenous nerve (16.7%; P = .052) and long saphenous vein (23.3%; P = .011). CONCLUSION: Minimally invasive fasciotomy of the anterior, peroneal, and deep posterior compartments using longitudinal incisions had a low rate of iatrogenic injury in a cadaveric model. Complete compartment release was achieved in 97% to 100% of specimens when employing this technique. CLINICAL RELEVANCE: Minimally invasive fasciotomy techniques for CECS have become increasingly popular with purported low recurrence rates, improved cosmesis, and faster return to sport. It is important to determine whether this technique is safe, particularly given the variable rates of neurovascular injury reported in the literature.

Dual-incision minimally invasive fasciotomy of the anterior and peroneal compartments for chronic exertional compartment syndrome of the lower leg.

To evaluate the risk of iatrogenic injury when using a dual-incision minimally invasive technique to decompress the anterior and peroneal compartments of the lower leg. Forty lower extremities from 20 adult cadavers, embalmed with Thiel's method, were subject to fasciotomy of the anterior and peroneal compartment using a dual-incision minimally invasive fasciotomy. The first incision was made 12 cm proximal to the lateral malleolus to identify and protect the superficial peroneal nerve (SPN). The second incision was made at the mid-point of the Fibula (half-way between the fibular head and the lateral malleolus). Release of the anterior and peroneal compartments was successful in all specimens. Two nerve injuries of the superficial peroneal nerve were reported. More precisely, in these cases the medial dorsal cutaneous nerve got injured during the fascial opening of the extensor compartment. Two incision minimally invasive fasciotomy to decompress the anterior and peroneal compartments of the lower leg appears to be safe with regard to the results of this study.

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.

Axillary nerve elongation in humeral fracture plating: A cadaveric study for comparison between straight and helical Philos plates.

Helical plating is a known concept in humeral fracture treatment. Attention should be paid to the axillary nerve when inserting a plate underneath the deltoid muscle. The purpose of this cadaveric study was to estimate axillary nerve stretching when introducing the plate. METHODS: On 42 fresh frozen human humeri, an 8-, 10- and 12-hole Philos plate in a straight and a helical shape were compared measuring the maximum plate-bone-distance. RESULTS: For all three plate lengths, the helical plates had a significantly lower plate-bone-distance. CONCLUSION: Indirectly, this suggests a lower axillary nerve elongation and hence less chance of nerve damage.

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.