Fabrice Duparc

Anatomical basis of the variable aspects of injuries of the axillary nerve (excluding the terminal branches in the deltoid muscle)

AbstractThe course of the axillary n. is complex with three points of angulation that may be used to delineate four segments and a fifth segment that corresponds to the intramuscular ending of the nerve in the deltoid m. The purpose of this study was to determine the precise anatomy of the nerve and of its branches, and some morphologic features for each segment. Thirty-two shoulders from embalmed adult cadavers have been studied. The axillary n. was divided in five segments: 1)from its origin to the inferior border of the subscapularis m.,2)from the subscapularis m. to the anterolateral border of the tendon of the long head of the triceps brachii m.,3)from the triceps to the posteromedial part of the surgical neck of the humerus,4)from the humerus to the entry into the deltoid m.,5)the intramuscular distribution of the nerve in the deltoid m.In each segment from 1 to 4 were noted the origins of the branches to the subscapularis and teres minor mm. and to the scapulohumeral joint, and the origins of the lateral cutaneous brachial n. and of the terminal motor branches to the deltoid m. The length and the diameter of the nerve in the segments and the distance from the segment S1 to the musculotendinous junction of the subscapularis m. were measured.The results showed that the mean diameters were about 4.1 mm in segment 1, 4.1 mm in segment 2 and 3.4 mm in segment 3. The mean distance to the musculotendinous junction was 7.7 mm. Many variations in the levels of origin of the different muscular, articular or cutaneous branches were found without symmetry between the right and left sides. The lateral cutaneous brachial n. was absent in four cases.The results are compared with those in the literature. The division into five segments is proposed to radiologists and surgeons for evaluation or operative procedures on the axillary n., and to provide a hypothesis about the variable aspects of injuries of the nerve.

Anatomical basis of the suprascapular nerve entrapment, and clinical relevance of the supraspinatus fascia

IntroductionThe entrapment of the suprascapular nerve (SSN) is commonly considered at the level of the suprascapular notch and more rarely in the spinoglenoid notch. Recent per-operative findings showed a compression of the SSN along its course in the supraspinatus fossa. The removal of a fascia for releasing the nerve between the suprascapular notch and spinoglenoid notch led us to purchase an anatomical study.Materials and methods30 cadaver shoulders have been dissected. The morphological features about the suprascapular notch, the supraspinatus fascia, and the spinoglenoid notch have been observed. Histological studies of the fascia and the spinoglenoid ligament have been performed. Morphometric parameters such as shape of the suprascapular notch, diameters of the SSN before and after the suprascapular notch, distance between the two notches, length of the course of the SSN into the supraspinatus fossa, diameters of the spinoglenoid notch have been measured.ResultsThe shape of the suprascapular notch could be seen as “U”- or “V” as previously reported. The fascia was quite constant (completely identified in 29 shoulders) and was the lateral extension of the supraspinatus fascia. The SSN coursed between the bone and the fascia and was surrounded by fat tissue. This fascia was thickened at the level of the spinoglenoid notch and joined the infraspinatus fascia. The spinoglenoid ligament was seen in 28 shoulders.Discussion and conclusionIn pathologic and post-trauma conditions, the fascia can be retracted or thickened and the SSN may be entrapped along its course in the supraspinatus fossa, between the suprascapular notch and the spinoglenoid notch and without any compression in any notch. These anatomical data lead us to consider that a tunnel syndrome may concern the SSN.

Review of the surgical anatomy of the axillary nerve and the anatomic basis of its iatrogenic and traumatic injury

The axillary nerve is invariably reported to be one of the most commonly injured nerves during surgical procedures of the shoulder, and the importance of protecting it cannot be overemphasized. Many researchers have tried to identify safe regions, but the results vary among published studies. The axillary nerve may also be injured during acute trauma to the shoulder or by chronic repeated trauma as has been described in the quadrilateral space syndrome. The nerve injury may occur together with shoulder dislocation and rotator cuff tear, thus comprising the so-called “unhappy triad” of the shoulder joint. Simple attention to potential variations in the origin and course of the axillary nerve and its relationship to the shoulder capsule and having a precise knowledge of “safe zones” during operations can enhance clinical outcomes. The objective of this review, therefore, is to discuss the surgical anatomy of the axillary nerve and further emphasize the clinical importance of the its injury following shoulder trauma.

Anatomic basis of the transgluteal approach to the hip-joint by anterior hemimyotomy of the gluteus medius

The authors present a study of the intrinsic anatomy of the gluteus medius m. and of its innervation through the caudal branch of the superior gluteal n. The existence of an intramuscular tendon in the thickness of the gluteus medius was constantly prooved in 40 muscles. The relations of the intrinsic fibrous structure of the muscle and its innervation were studied. The authors deduce from that the topography of a gluteus medius incision, with respect to a safety area towards its innervation, which leads to an exposure of the acetabulum that is satisfying and gives opportunities of a sound repair after the surgery of the hip joint through the transgluteal approach. They propose the “anterior hemimyotomy of the gluteus medius m” designation.

The arterial vascularization of the lateral tibial condyle: anatomy and surgical applications

The contribution of the inferior lateral genicular artery (ILGA) and the anterior tibial recurrent artery (ATRA) in the arterial supply of the lateral tibial condyle (LTC) has not been comprehensively studied and remains controversial. Eleven knee joints were injected with colored latex and the arteries were dissected macroscopically. The ATRA yielded several osseous branches supplying the tibial metaphysis and the anterior part of the tibial epiphysis and several rami supplying the anterior tibial tuberosity and the lower part of the patellar tendon. The ILGA ran under the lateral collateral ligament and had a horizontal direction towards the retro-patellar fat pad. The ILGA yielded 4–6 branches ascending or descending perpendicularly to its main direction. Full anastomoses between branches derived from the ATRA and the ILGA were observed in front and behind the lateral intercondylar tubercle in all the specimens, but each vessel seemed to provide predominantly the blood supply to a specific area. The anterior part of the LTC drew its blood supply from the ATRA, the posterior part from the ILGA and the mid-portion from both arteries. The standard anterolateral approach to LTC fractures with sub-meniscal arthrotomy appears particularly harmful to epiphyseal vascularization since it interrupts many of the branches deriving from the ILGA and ATRA. The recent development of arthroscopy in the treatment of LTC fractures may be particularly advantageous as it spares the vascularization of the LTC.

Vascular anatomical basis of clavicular non-union

The middle third of the clavicle is commonly involved in any injury and account for 5–10% of all fractures in adults. Although non-unions are rare, their treatment has not been well defined yet. This report describes the arterial supply of the clavicle to clarify the pathological mechanism and the surgical procedure of non-unions. This study was based on delineation of the thoraco-acromial and suprascapular arteries with colored latex on 17 specimens (ten cadavers). Observations were made after macroscopic dissection and maceration. The main blood supply to the middle third of the clavicle was the periosteal. This supply came from the two branches of the thoraco-acromial trunk that penetrated the pectoralis major muscle and the deltoid muscle. In 13 cases, these two periosteal branches were anastomosed between these two muscle attachments. Periosteal vascularization was always seen on the superior surface and the anterior border of the bone, but never on the inferior surface or the posterior border. The suprascapular artery contributed to supply the middle third of the clavicle by several periosteal branches and also by an independent branch. This branch was born proximally near the internal, middle thirds union and passed along the posterior face of the subclavius muscle and pierced the bone through the nutria foramina located near the external, middle thirds union. Nevertheless, intraosseous arteries were noted only in four cases. In these cases, they were never more than 2cm long. Our results showed that the periosteal blood supply located between the muscles insertions and the arterial supply from the suprascapular artery could be twice compromised in case of important displacement or severe fracture. If treatments of clavicular fractures or non-unions cannot preserve the periosteal blood supply, bone grafting should be indicated.

A plea for the use of drawing in human anatomy teaching

Descriptive human anatomy constitutes one of the main parts of the educational program of the first part of the medical studies. Professors of anatomy have to take into account the exponential evolution of the techniques of morphological and functional exploration of the patients, and the trend to open more and more the contents of the lectures of anatomy to clinical considerations. Basically, teaching requires a series of descriptive and educational media to set up, in front of the student, the studied structures and so to build the human body. More generally, lectures in morphological sciences try to develop three types of knowledge: declarative, procedural, and conditional. Traditionally in France “basic or first” anatomy is taught in amphitheater and in big groups by building each structure or region on a blackboard with colored chalk that allows a relief stake of certain structures and builds in two dimensions a three-dimensional organization. Actually, the blackboard is and stays for us an excellent media of non-verbal expression.

Complication rates and types of failure after arthroscopic acute acromioclavicular dislocation fixation. Prospective multicenter study of 116 cases

AIMS To report and analyze both the surgical and radiographic complications associated with anatomic coracoclavicular (CC) ligament procedures and to evaluate the effect of these complications on patient outcomes. PATIENTS AND METHODS From July 2012 to July 2013, 116 primary anatomic CC ligament procedures (all arthroscopic endobutton fixations) were performed in 14 different centers. Demographic, surgical, subjective, and radiographic data were prospectively analyzed in 14 centers with a minimum follow-up of 12 months. RESULTS This series included 96 men and 20 women, mean age 37 years old, with a mean delay to surgery of 10 days. No intraoperative complications were reported. There were 11 complications due to hardware failure resulting in a loss of reduction, 1 coracoid fracture, 7 cases of adhesive capsulitis, 2 local infections, 5 cases of hardware pain. There were significant differences in outcomes between patients who did and did not develop complications: mean CS=71 vs. 93, (P<0.0001). All the parameters of the CS were statistically affected (P<0.0001). Forty-eight patients had persistent dislocation>150% on an AP X-ray which affected the pain and activity CS (P=0.023 and P=0.044). No preoperative predictive factors were identified. These patients could not return to the same level of sports activities due to persistent pain. DISCUSSION Anatomic procedures to treat AC joint dislocation using CC ligament reconstruction resulted in an overall complication rate of 22.4% and influenced the return to sports. Good to excellent outcomes were reported in patients without complications. CLINICAL SERIES Level of evidence 4.

Reliability of radiographic measurements for acromioclavicular joint separations

INTRODUCTION The treatment of acromioclavicular (AC) joint separations is controversial, particularly for Rockwood type III injuries. Rockwood type IV injuries, which correspond to horizontal instability, are very likely under-diagnosed. The objective of this study was to evaluate the inter- and intra-observer reproducibility of the Rockwood classification through an evaluation of standard radiographs, as described in the original article. MATERIAL AND METHODS This was a prospective radiographic study using protocol-based data from the 2014 symposium of the French Society of Arthroscopy (SFA). Fifteen anonymized radiological records were analysed by six independent examiners on two occasions, 1 week apart. The records consisted of a comparative A/P view of the two acromioclavicular joints (Zanca view), an axillary lateral view and dynamic lateral views (Tauber protocol) to uncover dynamic horizontal instability. A detailed analysis protocol was implemented that included absolute and relative measurements on each view; the relative measurements were used to account for radiographic magnification. RESULTS The inter- and intra-observer reproducibility on the A/P radiographs was good to excellent. The reproducibility was fair to good on the lateral views, but the measurements varied greatly from one subject to another, and significant errors were found with certain records. The reproducibility of the dynamic views proposed by Tauber was poor to fair. DISCUSSION Radiographic analysis of AC joint separations is reproducible in the vertical plane, which makes it possible to diagnose Rockwood type II, III and V injuries. On the other hand, static and dynamic analyses in the horizontal plane do not have good reproducibility and do not contribute to make an accurate diagnosis of Rockwood type IV injuries. LEVEL OF EVIDENCE Level I, Diagnostic study.

Arterial anatomical basis of the dorsal digito-metacarpal flap for long fingers

Several flaps have been described to treat severe soft tissue defects of the finger dorsal side. Many authors studied vascular organization of the hand on its dorsal side; most of them insisted on deep vascularization into the intermetacarpal spaces, which is formed by the dorsal metacarpal arteries. Those dorsal metacarpal arteries are the anatomical support of many flaps, which do not preserve the dorsal interosseous muscles fascias. Only few authors described dorsal vascular organization at the level of the proximal phalanx; however, using a rotation point of a flap distally to the metacarpal head with a donor site on the dorsal aspect of the hand could cover all distal soft tissue defect of long finger. In order to determine the technical limitations of dorsal digito-metacarpal flap procedures, we studied number and location of arterial anastomoses between the reticular subcutaneous dorsal network and the rest of the vascularization at this level, which was formed by the deeper dorsal metacarpal arteries, common palmar digital arteries and proper palmar digital arteries, and between the dorsal digital arteries. Twenty-four long fingers from embalmed cadavers were studied after a reverse flow injection of colored latex and dissected layer-by-layer preserving the digital-metacarpal arterial network. At the level of the hand, the dorsal metacarpal arteries of the third and fourth intermetacarpal spaces were inconstant. When present, two or three arteries anastomosed in star shape with the reticular network. No such arterial anastomosis was observed proximally to the level of the intertendinous connections (junctura tendinorum) that bridge the extensor digitorum communis tendons. When no dorsal metacarpal artery was present, some communicant arteries arose from the common palmar digital arteries. Moreover, all the nutrient branches were more numerous distally to the intertendinous connections (junctura tendinorum). At the level of the metacarpophalangeal joints, the hand cutaneous network was always anastomosed with the dorsal cutaneous network. At the level of fingers, the dorsal cutaneous network was always supplied by four branches arising from the proper digital artery. Our study supported the reliability of dorsal digitometacarpal flaps, supplied by numerous palmodorsal digital anastomoses and by a rich plexiforme network joining the hand skin supply and that of the dorsal finger skin. During the procedure, we recommend limiting the surgical dissection of the flap at the level of the middle phalanx.