Abraham Guadalupe Espinosa-Uribe

Safe Areas for the Placement of Standard Shoulder Arthroscopy Portals: An Anatomical Study

The abundant vascular structures that surround the shoulder joint are complex and variable, complicating arthroscopy approaches. The aim of this study is to determine safe and risky areas around standard posterior and standard anterior portals, and accounting for the distribution of neurovascular structures of small and medium diameters that can lead to intra-articular bleeding during surgery. The standard posterior portal, and standard anterior portal were placed as described in the literature, and punch dissection was performed 2.5 cm around the trocar in situ. The arrangement of each identified structure was photographically documented and digitalized for each anatomic plane; the distance to the trocar and the diameter of each structure were measured. Based on each digitalized anatomic plane, safe and risky tissue areas were determined, and a clock face coordinate system was used to represent these areas. The safe area around the standard posterior portal was located between 11 and 1 o´clock for the left shoulder and 11 and 2 o´clock for the right shoulder. For the standard anterior portal, the safe area was located between 2 and 3 o´clock for the left shoulder and between 9 and 12 o´clock for the right shoulder. However, we did document a risk of injuring the cephalic vein 5 times, the axillary artery 3 times and the deltoid branch of the thoracoacromial artery once. This study reports quantitatively the total number of small diameter structures present in the two shoulder arthroscopic portals evaluated. The safe areas proposed in this study must be evaluated to propose new access points for performing arthroscopic procedures on the shoulder.

Neurovascular structures at risk during anterolateral and medial arthroscopic approaches of the hip

El objetivo fue describir las areas de seguridad para la colocacion de 5 portales estandar (portal anterior, anterolateral, posterolateral, portal anterior proximal medial y portal anterior distal medial) y 3 portales mediales emergentes (antero medial, portal posteromedial y posteromedial distal) para proporcionar una descripcion topografica de la seguridad de cada portal. Se realizo un estudio descriptivo, observacional y transversal, en la que se diseco el triangulo femoral de 12 caderas. Se colocaron los 5 portales laterales y los 3 portales mediales. Se documento la medicion de cada estructura neurovascular de relevancia clinica en relacion a cada uno de los portales evaluados. En cuanto al portal de mayor riesgo entre los laterales, se encontro el portal anterior con mayor cercania al nervio cutaneo femoral lateral (1,42±0,85 cm), ubicado lateral al portal. En los portales mediales el portal anterior medial tiene el margen mas estrecho respecto a la arteria femoral (2,14±0,35 cm) lateral al portal, y medial el nervio obturador (0,87±0,62 cm). Los portales laterales tienen un amplio margen de seguridad, el portal con el margen mas reducido es el portal anterior en relacion al nervio cutaneo femoral lateral, presentando un elevado riesgo de lesionarlo, los portales mediales tienen un alto riesgo de lesionar las estructuras neurovasculares femorales y el nervio obturador.

Comments on: Implications of structural variations in the human sacrum: why is an anatomical classification crucial?

We sincerely appreciate the work done by Mahato [1] in which a qualitative classification of the sacrum is done to determine the number of segments, position of auricular surfaces, symmetry and abnormalities. This work is of the utmost importance since it is crucial for several surgical interventions and at the same time correlates certain pathologies with the morphology, mostly low back pain. It would be of great benefit having a quantitative study of the sacrum, like the one performed by our working group, Morales et al. [2], in which the morphometric characteristics (sacral foramina, pedicles, vertebral body and sacral canal) of 50 sacral specimens in Mexican population were obtained. With this information it is possible to determine the most prevalent characteristics that are present in the sacrum in Mexican population, which are critical for a safe intervention and compare them with the existing literature. In our work it was possible to establish that the pedicle length of S1 was longer than reported in previous studies. We recommend performing a similar study to the working group of Mahato, in which the morphometric characteristics of the sacral in Indian population are obtained, with this adding valuable information to the proposed classification in predicting the most prevalent measures. This would give a chance to have safer procedures after having done a clinical correlation of the pathology based on Mahato [1] and predict the sacrum measurements based on a similar study to ours, with this having correct screw placement and position in lumbosacral instrumentation, and also for other procedures that involves the sacral region as surgical and diagnostic target. The classification proposed by the working group of Mahato is of essential importance since it correlates the form and characteristics of the sacrum with the patient symptoms and gives valuable information to the surgeon that will perform a procedure. Besides, it presents information on the several variations present on the sacrum to be able to identify them. We consider it is important to take into account both analyses [1, 2].

Concerning “Pathological findings in patients with low anterior inferior iliac spine impingement”

We applaud the recent article published by Amar et al. who evaluates the prevalence of low anterior inferior iliac spine (AIIS) in patients undergoing hip arthroscopy and characterizes the concomitant labral and chondral injuries. This study hypothesize that low AIIS is a common intraoperative finding in hip arthroscopy patients and that labral and chondral lesions may be found in a predictable location [1]. Currently, there is interest in extra-articular sources of femoroacetabular impingement (FAI), which may cause a small proportion of FAI cases and are exemplified by trochanteric-pelvic, ischiofemoral and subspine impingement [2]. Our working group recently published an article whose aim was to determine a new morphological classification of AIIS using a sample of 458 dry hemipelvises of known gender and age and to determine the prevalence of the different AIIS morphologies according to sex, age and laterality. Our results suggests that the prevalence of ‘‘abnormal’’ morphology (types 2A, 2B and 3) most commonly occurs in young men (18–39 years) and older women ([40 years) [4]. • Type 1: presents a notch or a concave surface between the AIIS and the acetabular rim, whereby the surface does not contact and is not part of the acetabular rim. • Type 2A: presents a flat surface between the AIIS and the acetabular rim, whereby the surface reaches the acetabular rim but is not continuous. • Type 2B: presents a convex surface (with or without bony prominences) between the AIIS and the acetabular rim, which continues directly with the acetabular rim. • Type 3: presents an AIIS that protrudes into the acetabulum inferiorly with invasion of the acetabular rim, interfering with the continuity of the same in its anterosuperior portion or presents a large anterior bony prominence with multiple spiculae and/or protruding bone [4].

Concerning the Article “Transhumeral Portal for Arthroscopic Glenohumeral Resurfacing Procedures: A Cadaveric Study of the Safety and Accuracy”

To the Editor: We sincerely applaud the work done by Bartosiak et al. in which the safety and accuracy of transhumeral portal was evaluated. This technique allows access to the surface of the glenohumeral joint and avoids transection of the subscapularis muscle or glenohumeral dislocation. It also reduces the risk of brachial plexus injury. A potential complication in the positioning of the arthroscopic portals is injury to neurovascular structures. We conducted a study in 13 shoulders to evaluate safe areas for arthroscopic portal placement; 2.5-cm diameter punch dissections were done with the portal as the center point. This technique allows a description of the in situ relationship between the portal and the circumferential structures, as well as the risk of injury, without distorting the anatomy. Our results match those reported in this study regarding the subcutaneous location of veins and branches of the axillary nerve; however, the authors fail to mention the potential intra-articular bleeding secondary to a transhumeral approach when performed in patients. This is relevant to the complication it may cause in visibility when performing the arthroscopic procedure. Similar studies with a larger sample number are needed, evaluating previous pathologies, as well as age and gender in the specimens studied. It is important to document the existence of in situ neurovascular structures that are vulnerable to portal manipulation. It is also essential to evaluate the risk of fracture or complications after drilling in the humeral head. It is important to distinguish the approach as useful and innovative to access the surface of the glenohumeral joint or that it provides excellent accuracy to reach the center-center of the humeral and glenoid articular surfaces, which is essential to locate and repair cartilage lesions.