Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study. / Comparación de tres técnicas de tornillo endomedular mínimamente invasivo para fracturas de falange proximal. Estudio biomecánico.

BACKGROUND AND OBJECTIVE: Phalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels. MATERIAL AND METHODS: We performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15 mm in the other 15. In turn, in each group, five fractures were stabilized with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS. RESULTS: Anterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74 N and 70.86 N, respectively) was found to be more stable than retrograde IMHCS one (32.72 N) (p = 0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52 N retrograde vs. 57.64 N trans-articular vs. 42.92 N intra-articular; p = 0.20). CONCLUSIONS: Anterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.

[Translated article] Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study.

BACKGROUND AND OBJECTIVE: Phalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels. MATERIAL AND METHODS: We performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15mm in the other 15. In turn, in each group, five fractures were stabilised with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS. RESULTS: Anterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74N and 70.86N, respectively) was found to be more stable than retrograde IMHCS one (32.72N) (p=0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52N retrograde vs. 57.64N trans-articular vs. 42.92N intra-articular; p=0.20). CONCLUSIONS: Anterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.

Role of imaging techniques in the diagnosis of selective hypertrophy of the tensor fascia lata.

The tensor fascia lata is a muscular structure that forms part of the lateral portion of the pelvis and proximal thigh. Because conditions affecting this muscle have not been widely reported and are relatively unknown, hypertrophy and pseudo-hypertrophy of the tensor fascia lata, although relatively common imaging findings, often go undiagnosed; instead, radiologists perform the differential diagnosis with more complex and more dangerous conditions. This article aims to review the anatomic and functional characteristics of the tensor fascia lata, going into detail about the radiological description of this muscle and pathological conditions that can affect it, as well as reviewing the relevant literature.

A newly discovered membrane at the origin of the proximal tendinous complex of the rectus femoris.

PURPOSE: The rectus femoris (RF) forms the anterior portion of the quadriceps muscle group. It has a proximal tendinous complex (PTC) which is constituted by a direct tendon (DT), an indirect tendon (IT), and a variable third head. Direct and indirect tendons finally converge into a common tendon (CT). All the PTC shows a medially sloping in its proximal insertion.We investigated several anatomical specimens and discovered a new component: a membrane connecting the CT with the anterior superior iliac spine. Such membrane constitutes a new origin of the PTC. The aim of this study was to clarify whether this membrane was an anatomical variation of the PTC or a constant structure and to describe its morphology and trajectory. MATERIAL AND METHODS: We dissected 42 cadaveric lower limbs and examined the architecture of the PTC. We paid special attention to the morphology and interaction patterns between the tendons and the membrane. RESULTS: We demonstrated that the membrane is a constant component of the PTC. It has a lateral to medial trajectory and is in relation to the common tendon, the DT, and IT, which present a medial slope. This suggests that the membrane has an stabilizer role for the PTC, acting as a corrector of the inclined vector of the complex. CONCLUSION: The RF injuries are frequent in football. The newly discovered membrane is a constant component of the PTC and its integrity should be included in the algorithm to diagnose injuries.

How 3D patient-specific instruments improve accuracy of pelvic bone tumour resection in a cadaveric study.

OBJECTIVES: To assess the accuracy of patient-specific instruments (PSIs) versus standard manual technique and the precision of computer-assisted planning and PSI-guided osteotomies in pelvic tumour resection. METHODS: CT scans were obtained from five female cadaveric pelvises. Five osteotomies were designed using Mimics software: sacroiliac, biplanar supra-acetabular, two parallel iliopubic and ischial. For cases of the left hemipelvis, PSIs were designed to guide standard oscillating saw osteotomies and later manufactured using 3D printing. Osteotomies were performed using the standard manual technique in cases of the right hemipelvis. Post-resection CT scans were quantitatively analysed. Student's t-test and Mann-Whitney U test were used. RESULTS: Compared with the manual technique, PSI-guided osteotomies improved accuracy by a mean 9.6 mm (p < 0.008) in the sacroiliac osteotomies, 6.2 mm (p < 0.008) and 5.8 mm (p < 0.032) in the biplanar supra-acetabular, 3 mm (p < 0.016) in the ischial and 2.2 mm (p < 0.032) and 2.6 mm (p < 0.008) in the parallel iliopubic osteotomies, with a mean linear deviation of 4.9 mm (p < 0.001) for all osteotomies. Of the manual osteotomies, 53% (n = 16) had a linear deviation > 5 mm and 27% (n = 8) were > 10 mm. In the PSI cases, deviations were 10% (n = 3) and 0 % (n = 0), respectively. For angular deviation from pre-operative plans, we observed a mean improvement of 7.06° (p < 0.001) in pitch and 2.94° (p < 0.001) in roll, comparing PSI and the standard manual technique. CONCLUSION: In an experimental study, computer-assisted planning and PSIs improved accuracy in pelvic tumour resections, bringing osteotomy results closer to the parameters set in pre-operative planning, as compared with standard manual techniques.Cite this article: A. Sallent, M. Vicente, M. M. Reverté, A. Lopez, A. Rodríguez-Baeza, M. Pérez-Domínguez, R. Velez. How 3D patient-specific instruments improve accuracy of pelvic bone tumour resection in a cadaveric study. Bone Joint Res 2017;6:577-583. DOI: 10.1302/2046-3758.610.BJR-2017-0094.R1.

Transfer of the musculocutaneous nerve branch to the brachialis muscle to the triceps for elbow extension: anatomical study and report of five cases.

We report the study of the anatomical feasibility of transferring the nerve to the brachialis muscle to the upper medial head motor branch that innervate the triceps, and outcomes of such transfers in restoring elbow extension in five patients with posterior cord lesion of the brachial plexus. The length of the branches to the brachialis muscle measured 7.6 cm and the triceps upper medial head motor branch was 5 cm in 10 adult cadavers. Five male patients were treated with this transfer 5 months after the injury (range 4 to 6 months) after posterior cord injury of the brachial plexus with a mean follow-up of 31 months (range 28 to 36 months). Elbow extension scored M4 in all cases. No complications occurred. These preliminary results suggest that transferring the nerve to the brachialis muscle is an effective technique for the reconstruction of elbow extension after posterior cord brachial plexus injuries. LEVEL OF EVIDENCE: IV.

Surface anatomical landmarks for the location of posterior sacral foramina in sacral nerve stimulation.

BACKGROUND: Sacral nerve stimulation is a common treatment for various pelvic floor disorders. It consists of the percutaneous introduction of electrodes through the posterior sacral foramina for therapeutic stimulation of the target sacral spinal nerve. The aim of our study was to determine the surface anatomical landmarks of the sacrum to facilitate identification of the posterior sacral foramina. METHODS: This study was conducted on 20 human cadavers. The cadavers were placed in a prone position, and all the soft tissues of the sacral region were removed to allow exposure of the osseous structures. Different measurements were taken in relation to the posterior sacral foramina, the posterior superior iliac spine (PSIS) and the median sacral crest (MSC). A median coefficient of variation (CV) was determined. RESULTS: The diameter of the second sacral foramen showed the greatest variability. The distances between each individual foramen and the MSC had an acceptable variability (CV < 20%). In contrast, the distance between foramina had a high variability. The distance between PSIS and the second posterior sacral foramen was also found to have an acceptable variability (CV < 20%). However, the angle formed by an horizontal line between PSIS and a line between PSIS and S2 foramina had high variability. CONCLUSIONS: We found that the distance between sacral foramina and MSC is relatively constant while the distance between foramina and the relations between foramina and PSIS is highly variable. Detailed knowledge of the anatomy may facilitate electrode placement and is complementary to the regular use of fluoroscopy.

Imaging of cellular aging in human retinal blood vessels.

To date two main aging vascular lesions have been reported in elderly human retinas: acellular capillaries and microaneurysms. However, their exact mechanism of formation remains unclear. Using high resolution microscopy techniques we revise cellular alterations observed in aged human retinal vessels, such as lipofuscin accumulation, caveolae malfunction, blood basement membrane disruption and enhanced apoptosis that could trigger the development of these aging vascular lesions. Moreover, we have generated a set of original images comparing retinal vasculature between middle and old aged healthy humans to show in a comprehensive manner the main structural and ultrastructural alterations occurred during age in retinal blood vessels.

Mimicking microvascular alterations of human diabetic retinopathy: a challenge for the mouse models.

Although it has become acceptable that neuroretinal cells are also affected in diabetes, vascular lesions continue to be considered as the hallmarks of diabetic retinopathy. Animal models are essential for the understanding and treatment of human diabetic retinopathy, and the mouse is intensively used as a model because of its similarity to human and the possibility to be genetically modified. However, until today not all retinal vascular lesions developed in diabetic patients have been reproduced in diabetic mice, and the reasons for this are not completely understood. In this review, we will summarize retinal vascular lesions found in diabetic and diabetic-like mouse models and its comparison to human lesions. The goal is to provide insights to better understand human and mice differences and thus, to facilitate the development of new mouse models that mimic better human diabetic retinopathy.

[Carpal dynamic stability mechanisms. Experimental study]. / Mecanismos de estabilización dinámica del carpo. Estudio experimental.

OBJECTIVE: To evaluate, experimentally in cadavers, the effect of the motor muscles in the wrist in the kinetic behaviour of the carpal, under axial load, and the wrist in a neutral position. MATERIAL AND METHOD: The changes in the spatial orientation of the carpal bones were recorded with a movement trajectory gauge that functions with electromagnetic fields. A total of 30 fresh cadaver wrists were used, in which the principal motor tendons were isolated and subjected to loads proportional to the area of the physiological section of each muscle. The experiment was performed under isometric load conditions of all the tendons, and separately from each tendon. RESULTS: The simultaneous load of all the tendons studied caused a three-dimensional change of the carpal bones. The flexor carpi radialis led to supination of the scaphoids and pronation of the pyramidal. Conversely, the isolated load of the flexor carpi ulnaris, abductor pollicis longus and the extensor carpi radialis longus, caused a supination movement of the 2 carpal rows. Only the extensor carpi ulnaris led to a marked pronation of the carpal. COMMENTS AND CONCLUSIONS: The forearm muscles, as well as the movements of the wrist, cause pronation/supination/supination, flexion/extension and radial/cubital inclination movements. It is proposed that the most important movements in the dynamic stabilisation of the carpal are the intercarpal pronation and supination movements provoked by these muscles. Depending on the carpal injury mechanism or instability, the stimulating of one muscle group or the other may be beneficial.

Role of the extensor carpi ulnaris and its sheath on dynamic carpal stability.

Ten cadaveric forearms were tested using a wrist testing apparatus specifically designed to investigate the mechanisms of muscle stabilization of the wrist. The specimens were set in a jig allowing the distal row to migrate proximally and rotate around the axis of pronosupination. The extensor carpi ulnaris (ECU) was loaded with specific weights. Reactive rotations of the scaphoid, triquetrum, and capitate were measured by an electromagnetic motion tracking device. Loading the ECU caused pronation of both proximal and distal rows. After sectioning its sheath, the overall direction of the movement remained unchanged, but there was a 40% and 50% decrease of the pronation power over the distal and proximal carpal row, respectively. In addition to stabilizing the distal radiolunar joint, the ECU is an important structure that contributes to the dynamic stability of the wrist. Furthermore, its sheath plays a crucial role in maintaining the effect of the ECU muscle on the carpus.

Effects of forearm muscles on carpal stability.

Thirty cadaveric forearms were tested using a wrist testing apparatus specifically designed to investigate the mechanisms of muscle stabilization of the wrist. The specimens were set in a jig allowing the distal row to migrate proximally and to rotate around the pronosupination forearm axis. Five wrist motor tendons (FCR, FCU, ECU, ECRL and APL) were loaded with specific weights. Reactive rotations of the scaphoid, triquetrum and capitate were measured by an electromagnetic motion tracking device. When all five tendons were loaded simultaneously, the capitate supinated and the proximal row predominantly supinated and flexed. By contrast, when the ECU was loaded in isolation, it caused pronation to both proximal and distal rows. The FCR exhibited a mixed effect pronating the capitate and triquetrum, whilst supinating the scaphoid. Based on this, a hypothesis is proposed linking wrist stability to the balance of wrist pronators (ECU and FCR) and supinators (FCU, ECRL and APL).

The role of the flexor carpi radialis muscle in scapholunate instability.

PURPOSE: The flexor carpi radialis (FCR) muscle has been suggested to act as a dynamic scaphoid stabilizer. Because the FCR tendon uses the scaphoid tuberosity as a pulley to reach its distal insertion onto the second metacarpal, it has been hypothesized that FCR muscle contraction generates a dorsally directed vector that resists the scaphoid from rotating into flexion. The purpose of the present study was to validate that hypothesis and clarify the role of the FCR as a dynamic scaphoid stabilizer. METHODS: Ten fresh cadaver wrist specimens were tested. A custom-designed testing apparatus was used to hold the forearm and wrist vertically, in neutral forearm rotation. A 6-degree-of-freedom, electromagnetic motion-tracking device, with sensors attached to the scaphoid, triquetrum, capitate, and radius, was used to monitor spatial changes in carpal alignment as a result of isometrically loading the FCR in 5 different wrist positions. RESULTS: In all specimens and all wrist positions, the scaphoid consistently rotated into flexion when the FCR was loaded. It also exhibited variable degrees of pronation or supination, depending on whether the wrist was in flexion or extension. When the wrist was loaded in neutral position, the scaphoid consistently supinated and the triquetrum pronated, these differences being statistically significant (p < .05). CONCLUSIONS: The scaphoid consistently rotated into flexion and supination when the FCR was loaded, while the triquetrum rotated in flexion and pronation. The positive effects of FCR muscle re-education in dynamic scapholunate instabilities can be explained not by this muscle's capability of extending the scaphoid, as has often been hypothesized, but by its ability to induce supination to the scaphoid and pronation to the triquetrum. Such opposite rotations are likely to result in a dorsal coaptation of the scapholunate joint with relaxation of the dorsal scapholunate ligament.

Anthropometric characteristics of the pubic arch and proper function of the defense mechanisms against hernia formation.

In 33 inguinal regions, we determined the anthropometric characteristics of the pubic arch and the anatomic structures of the suprainguinal space and assessed whether there is a relationship between anatomic features and function of the defense mechanisms. There was a low position of the pubic arch (pubic tubercle and interspinal line distance >75 mm) in 23 cases. The low-pubic-arch group showed a significantly longer inguinal ligament and a greater angle made by the superior border of the suprainguinal space and the inguinal ligament at its medial insertion. The position of the pubic arch correlated significantly with the diameter of the internal ring, the length of the inguinal ligament, and the angle made by the superior border of the suprainguinal space and the medial insertion of the inguinal ligament. A low pubic arch would represent an unfavorable condition for an adequate function of the anatomic defense mechanism against hernia.

[Anatomic study of parapharyneal space]. / Estudio anatómico del espacio parafaríngeo.

The parapharyngeal space is considered the key space of the suprahioid neck, being essential to establish the origin and anatomic relations of the lesions of the profound neck. The descriptions of the fascial limits of the parapharyngeal space are variable in the litterature, reflecting some ambiguity in the manuals of anatomy and surgery. We have done a detailed study of this region, working on 5 cadavers, fixed in a solution of phenol and alcohol, and correlating the disection pieces with a radiologic study. The goal has been to improve our anatomic knowledge of the suprahioid neck, to be able to establish an anatomo-clinic-radiologic correlation of the lesions of this region, to be able to establish an differential diagnosis, predict possible ways of dissemination and facilitate the most proper surgical approach.

[Bronchial arteries: anatomical and clinical studies and strategies in surgical approach]. / Arterie bronchiali. Studio anatomo-clinico e strategie di accesso chirurgico.

One of the most important and controversial aspects of thoracic surgery is due to the topographical and surgical anatomy of the vascular structures involving the mediastinum. The knowledge of the so-called "vascular time", in fact, allows to face more complicated surgical situations, typical of the most specialistic thoracic surgery. The bronchial arteries represent a paradigm of what we have just stated. The study of their anatomy (number, position, origin, distribution and relationships with the mediastinal structures) is of relevant importance, not only for the interest the bronchial vascular tree arises in tracheo-bronchial surgery and in pulmonary transplantology, but also for the knowledge of the pathogenesis of some processes regarding pulmonary and pleural pathologies. The aim of this paper is to evaluate the real clinical interest of bronchial arteries, with an analytic study of the anatomy of vessels, and with the possibility to show the most frequent and characteristic anomalies involving the origin and course of these arteries.

Clinical anatomy of the arterial supply of the human patellar ligament.

The arterial supply of the human patellar ligament has been systematized on 20 knee joints. After intravascular injection of colored natural latex, the blood supply to the extensor apparatus of the knee was studied by anatomical dissection and tissue transparentation techniques. Three arterial pedicles (superior, middle and inferior) were observed placed on each side of the patellar ligament. Medial pedicles had their origin from the descending and the inferior medial genicular arteries. The lateral pedicles took their origin from the lateral genicular arteries and the recurrent tibial anterior artery. Two main vascular arches anastomosed with these pedicles: the retropatellar and the supratubercular. Both arterial pedicles and anastomotic arches gave rise to a peritendinous network, characterized by a high vascular density next to poles of the patellar ligament. Only the anastomotic arches gave rise to collateral vessels that pierced the tendon, which revealed two vascular segments in the arterial supply of the patellar ligament (bipolar pattern). The upper segment was supplied by deep vessels from the retropatellar arch, whereas the inferior segment received superficial vessels from collaterals of the supratubercular arch. These intratendinous vessels anastomosed in the middle third of the patellar ligament.

Is the reversed fourth dorsal metacarpal flap reliable?

We have carried out a study to determine if a flap based on vessels in the fourth metacarpal space could be used safely. We studied ten fresh cadaver specimens and used the flap in nine patients. In the anatomical study, we confirmed the presence of a suitable artery in nine out of the ten hands, arising from a piercing artery at the metacarpal bases, running distally under the fascia. The pivot point is located at the metacarpal heads, where the artery anastomoses to palmar branches and dorsal digital branches. In the clinical setting, the flap was reliable in eight patients. There was one case of flap necrosis. The flap seems to be reliable but several technical points are stressed to avoid complications.

An accessory belly of the abductor digiti minimi muscle: a case report and embryologic aspects.

Accessory fasciculi of the hypothenar muscles have been involved in vascular and nerve compressions. During a routine dissection an accessory belly of the abductor digiti minimi muscle arising from the tendon of the palmaris longus muscle was found in the lower third of the forearm. The accessory fasciculus ran through Guyon's canal enclosing the ulnar nerve and vessels. It was attached by means of two tendons where the fibres of the abductor digiti minimi muscle ended in a single pennate form. This anatomic variation was associated with a marked reduction of the caliber of the fourth tendon of the flexor digitorum superficialis muscle and a split of the median nerve. The nerve supply arose from the ulnar nerve. A fibrous band originating from this accessory muscular belly was found covering the median nerve. Based on the development of muscles and fibrous structures within the hand and forearm, as well as on our results, we consider the present anomalies as an unusual persistence of an undifferentiated group of mesenchymal cells. These belong to the superficial muscular anlagen layer of the hand, just between the flexor digitorum superficialis muscle blastema (which has the capacity of migration) and that for the abductor digiti minimi muscle.

[Importance of morphostructural changes observed in cortical micro-vessels in patients who died after a severe head injury]. / Relevancia de las alteraciones morfoestructurales detectadas en la microvascularización de la corteza cerebral en pacientes fallecidos por traumatismo craneoencefálico grave.

INTRODUCTION: The development of secondary lesions in traumatic head injuries seems to be a determinative factor for the survival of these patients. Endothelium damage of cortical microvessels could be fundamental in the main secondary lesions as cerebral ischemia and intracranial hypertension. OBJECTIVES: To investigate which are the main morphological changes that can be observed in cortical microvessels from these patients. MATERIAL AND METHODS: We have studied 15 fresh human brains from subjects died after a severe head injury. The study has been carried out by scanning electron microscopy of vascular corrosion casts and confocal microscopy of histological sections after immunocytochemistry, as well as detection of apoptosis by TUNEL technique. RESULTS AND CONCLUSIONS: The most significant structural alterations were observed mainly on arterioles and capillaries of the middle and deep vascular zones of the cerebral cortex. Corrosion casts showed vessels with longitudinal folds, sunken surface with craters and flattened vessels with reduced lumen. Histological sections immunostained with MAS-336 also showed vessels with longitudinal folds and thinning of their vascular lumen, the presence of cytoplasmic round bodies and a thickening of endothelial cell membrane. TUNEL method revealed a positive staining of some endothelial cells. The structural alterations observed seem to reveal a situation of cellular damage of endothelium in the human cortical microvessels from these patients. It can be thought that this kind of lesions, as well as the secondary functional injury of the blood brain barrier, could play an important role in the development of secondary damage.