JSES International 7 (2023) 673e677 Contents lists available at ScienceDirect JSES International journal homepage: www.jsesinternational.org Needle arthroscopy of the elbow through an anterior transbrachial portal Jose M. Rapariz, MD, PhDa,*, Ana M. Far-Riera, MDa, Carlos Perez-Uribarri, MDa, Silvia Martin-Martin, MD, PhDb, Alfonso Rodriguez-Baeza, MD, PhDc a tzer Hospital, Palma de Mallorca, Spain Son Lla b Clinica Rotger, Palma de Mallorca, Spain c noma de Barcelona, Barcelona, Departament of Morphological Sciences (Human Anatomy and Embryology Unit), Faculty of Medicine, Universitat Auto Spain a r t i c l e i n f o Background: Current innovation in needle arthroscopy is improving the safety of anterior portals around the elbow. This study evaluated the proximity to the radial nerve, median nerve, and brachial Keywords: artery on cadaveric specimens of an anterior portal used for elbow arthroscopy. Elbow arthroscopy Methods: Ten fresh-frozen adult cadaveric extremities were used. After marking the cutaneous refer- Anterior portal ences, the NanoScope cannula was introduced just lateral to the biceps tendon, through the brachialis Transbrachial portal muscle and the anterior capsule. Elbow arthroscopy was performed. Dissection was then carefully per- Needle arthroscopy formed on all specimens with the NanoScope cannula in place. The shortest distance from the cannula to Nanoscope Safety the median nerve, radial nerve, and brachial artery was measured with a handheld sliding digital caliper. Results: The cannula was an average of 12.92 mm away from the radial nerve, 22.27 mm from the Level of evidence: Anatomy Study; Cadaver median nerve, and 16.8 mm from the brachial artery. Needle arthroscopy performed through this portal Dissection allows complete visualization of the anterior compartment of the elbow, as well as direct visualization of the posterolateral compartment. Conclusion: Needle arthroscopy of the elbow through an anterior transbrachialis portal is safe for the main neurovascular structures. In addition, this technique allows complete visualization of the anterior and posterolateral compartments of the elbow through the humerus-radius-ulna space. © 2023 The Author(s). Published by Elsevier Inc. on behalf of American Shoulder and Elbow Surgeons. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by- nc-nd/4.0/). Elbow arthroscopy is a technically demanding procedure. The neurovascular anatomy, mainly the radial and median nerves and close relationship with neurovascular structures makes it mandatory the brachial artery. to understand its neurovascular anatomy.7,9 The median and radial Current innovation of needle arthroscopy might help facilitate nerves lie in close relation to the anterior aspect of the elbow and are improved safety of new portals around the elbow.12-14 at risk of iatrogenic injury when performing elbow arthroscopy. We questioned whether arthroscopic access to the anterior Over the past decades, multiple authors described several compartment of the elbow from an anterior portal was possible and arthroscopic portal locations and their relationship with the neu- the risk of injury to the main neurovascular tissue with this approach. rovascular structures.1,4-10,15-17 The most common portals used to The purpose of this study was to evaluate the proximity to the access the anterior elbow compartment include the proximal radial nerve, median nerve, and brachial artery on cadaveric spec- anterolateral and mid anterolateral portals from the lateral side, imens of an anterior portal used for elbow arthroscopy. and the proximal anteromedial portal on the medial side. Other We hypothesized that the anterior portal maintains safety anterior portals were discarded due to the risk of injury to critical margins (defined as 10 mm) comparable to classic portals. Materials and methods Institutional review board approval was not required for this study. This work was performed at the Department of Morphological Sciences (Human Ten fresh-frozen adult cadaveric extremities were used for the Anatomy and Embryology Unit). Faculty of Medicine, Universitat Auto  noma de present study. All cadavers were collected from persons who had Barcelona, Barcelona, Spain. *Corresponding author: Jose M. Rapariz, MD, PhD, C/ Vista Alegre 23, 1 D, Palma expressed the willingness to donate their bodies for medical and de Mallorca 07015, Spain. scientific purposes signing a form approved by the Human Experi- E-mail address: jrapariz@gmail.com (J.M. Rapariz). mentation Ethics Committee of the Universitat Auto  noma de https://doi.org/10.1016/j.jseint.2023.02.012 2666-6383/© 2023 The Author(s). Published by Elsevier Inc. on behalf of American Shoulder and Elbow Surgeons. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). J.M. Rapariz, A.M. Far-Riera, C. Perez-Uribarri et al. JSES International 7 (2023) 673e677 Figure 1 References for portal placement were: on the transverse plane, the flexion Figure 2 The shortest distance from the nerve or artery to the cannula was measured. crease of the elbow. This line is parallel to the virtual line connecting medial and lateral This distance constitutes the radius of the circle in which the nerve or artery are epicondyles of the elbow, and on the sagittal plane just lateral to the biceps tendon. tangential at a single point. Barcelona (procedure 2904 approved on March 27, 2015). None of retracted laterally as well. The sharp trocar was introduced into the the specimens had evidence of prior surgery or injury to the elbow. joint, pointing to the olecranon on the axial plane. All were verified for full elbow range of motion. Specimens were The NanoScope was introduced through this cannula into the amputated at the level of the proximal humerus for fixation pur- joint to confirm intra-articular placement. The pump pressure was poses. The median age of the donors at the time of death was 81 set to 30 mm Hg, and the anterior compartment arthroscopy was years (range, 62-92 years). There were 7 male and 3 female speci- recorded. The Video 1 shows the entire steps of the arthroscopic mens and 5 right and 5 left extremities. After being stored at 20 C, procedure. the specimens were thawed to room temperature prior to dissection. The second phase was an open anatomic dissection. Before The NanoScope arthroscopic system (Arthrex, Naples, FL, USA) beginning the dissection, the pump was stopped to allow the joint was used. This system consists of a disposable handpiece and a to be emptied. Dissection was then carefully performed on all tablet-like control unit. An light emitting diode light source is specimens with the NanoScope cannula in place. included in the handpiece. The handpiece tube is 9.5 cm long, Skin and subcutaneous tissues were removed, and the muscles semirigid, and has a 1.9 mm outer diameter. The scope’s direction of penetrated by the cannulas were documented. The radial nerve was view is 0 , with a 120 field of view. The cannula has a 2.26 mm identified in the interval between the brachialis and the brachior- outer diameter. adialis muscles and traced distally as it penetrated the supinator The first phase of the study entailed placing the elbow on the muscle. The median nerve was then identified under the lacertus table in 60 of flexion. The humerus was fixed with a pressure fibrosus and traced proximally. clamp, and the height was adjusted using a goniometer to hold the A single observer performed all measurements. Measurements elbow at 60 of flexion. We did not use transfixing Steinman pins to were performed with a handheld sliding digital caliper calibrated to avoid interference with the arthroscopic examination of the joint. 0.01 mm. Measurements were made from the medial aspect of the References for portal placement were: 1) on the transverse radial nerve to the lateral aspect of the cannula and from the lateral plane, the flexion crease of the elbow. This line is parallel to the aspect of the median nerve to the medial aspect of the cannula. The virtual line connecting medial and lateral epicondyles of the elbow, shortest distance from the nerve or artery to the cannula was and 2) on the sagittal plane just lateral to the biceps tendon. measured. This distance constitutes the radius of the circle in which Marks were made on the skin to provide accurate reference the nerve or artery is tangential at a single point (Fig. 2) points for portal placement (Fig. 1). Both the cephalic vein and the lateral antebrachial cutaneous nerve are located in the subcutaneous Results plane of this anterior portal. Therefore, it is convenient to dissect and protect them through a 2 cm transverse incision. Through this inci- None of the portal cannulas came in contact with the main sion, the cephalic vein was identified and retracted laterally. When neurovascular structures, and distances between portals and such the lateral antebrachial cutaneous nerve was identified, it was tissue were sufficiently high. 674 J.M. Rapariz, A.M. Far-Riera, C. Perez-Uribarri et al. JSES International 7 (2023) 673e677 Table I Distance from the canula to the radial and median nerve. Specimen Radial nerve Median nerve Brachial artery 1 10.73 26.89 20.78 2 10.06 23.31 20.18 3 9.08 20.16 18.95 4 13.58 20.96 19.63 5 9.94 22.76 18.45 6 13.38 29.29 17.28 7 14.65 19.11 17.61 8 10.3 20.23 21.38 9 15.54 21.06 13.99 10 12.92 18.93 13.74 Standard deviation 2.26 3.41 2.63 Average 12.018 22.27 18.199 The cannula was an average of 12.92 mm (standard deviation [SD] 5.61 mm) away from the radial nerve, an average of 22.27 mm (SD 3.41 mm) away from the median nerve, and an average of 16.8 mm (SD 3.13 mm) away from the brachial artery. Data and measurements are summarized in Table I. In all cases, it was possible to perform elbow arthroscopy through the anterior portal previously described. Elbow ar- throscopies were recorded. This portal allowed complete visu- alization of the anterior compartment of the elbow, including the proximal and distal capsular insertion. This visualization is comparable to that obtained with the combined anterolateral and anteromedial portals but without the need to interchange the position of the scope. In addition, the small diameter of the cannula allowed direct Figure 3 The small diameter of the cannula allowed direct access to the posterolateral access to the posterolateral aspect of the elbow. This access is aspect of the elbow, through the space between the humerus, ulna, and radius, just achieved through the space between the humerus, ulna, and radius, above the proximal radioulnar joint. just above the proximal radioulnar joint, which we have named as “HURT” (“humerus-ulna-radius through”) (Fig. 3). During superficial dissection, the proximity of the cephalic vein joint. We have shown that, following the references indicated in is verified. However, this proximity was not determined in this this article, the NanoScope can be introduced through the HURT study. Nor did we measure the distance from the cannula to the space. In this way, it is possible to visualize the proximal radioulnar brachial cutaneous nerves. joint as well as the posterolateral compartment, which was clas- After removing the subcutaneous tissue, the cannula pierces the sically accessed exclusively through an independent portal called brachialis muscle in all cases. When deep planes are dissected, a the "soft spot". triangular space with a proximal base and a distal apex can be seen. Several portals have been described to access the elbow joint's The lateral border of this triangle is the radial nerve itself, and the anterior compartment. Three of these approaches from the lateral medial border is the biceps tendon. Due to this triangular config- aspect, and the other three from the medial side.3 However, the uration, the more proximally the access site is located then the denomination and description of these portals are often redundant further it is from the radial nerve in the 10 specimens evaluated. and complex. As with the classic lateral and medial portals, when (Fig. 4) performing the anterior transbrachialis portal, we must avoid the use of distal portals. We must not go distal to the elbow flexion Discussion crease; otherwise, the distance to the radial nerve is significantly shortened. This is explained by the configuration of the previously The elbow is a complex joint. Unlike the knee joint, the described triangular space, in which the radial nerve constitutes neurovascular structures at risk on the elbow are located anteriorly. the lateral edge of the triangle (Fig. 4) For this reason, the anterior region of the elbow has not been In order to compare the mean distance between the different considered for an anterior portal and would be considered portals and the median and radial nerves, we followed the scheme "suicidal" due to the theoretical risk of injury to important vessels proposed by Camp.3 This author distinguishes 3 medial portals and and nerves. Multiple studies have been published to assess the risk 3 lateral portals to access the anterior compartment of the elbow. of neurovascular injury from the classic, medial, and lateral Comparing the distances between the different portals, we can portals.4,5,9-13 However, we are unaware of any other anatomical verify that the anterior transbrachialis portal is further from the study assessing the risk from an anterior portal. median, radial, and brachial artery than any of the classic portals Until now, elbow arthroscopy allows a peripheral view of the (Table I). joint. This is due to the narrow space separating the humerus's Although the anterocentral transbrachialis portal has been articular surfaces from the ulna and radius. However, the devel- previously described, it was published as a technical note and is not opment of needle arthroscopy has allowed the use of smaller di- based on any cadaver study.11 Moreover, they used 8 mm cannulas, ameters and more flexible optics.12-14 Thanks to this great which greatly narrows the safety margins with respect to neuro- technological advance, elbow arthroscopy is no longer limited to vascular structures. In addition, they propose the transbrachialis peripheral vision but rather allows access to the very center of the portal as a working portal, not a viewing portal. 675 J.M. Rapariz, A.M. Far-Riera, C. Perez-Uribarri et al. JSES International 7 (2023) 673e677 Table II Strengths and limitations of the anterior portal. Strengths 1. Strengths of the supine position: a. Unobstructed access to the airway for anesthesia b. Arm freely positioned in space c. Easy conversion to open procedure, if required. 2. Complete visualization of the anterior compartment through a single portal. 3. Complete visualization of the proximal radioulnar joint 4. Complete visualization of the posterolateral compartment through the HURT space Limitations 1. Access to the posterior compartment may be more cumbersome HURT, humeral-ulnar-radius through. nerve, and brachial artery. In addition, this technique allows com- plete visualization of not only the anterior compartment but also the posterolateral compartment of the elbow through the HURT space. Disclaimers: Funding: No funding was disclosed by the authors. Conflicts of interest: The authors, their immediate families, and any Figure 4 A triangular space with a proximal base and a distal apex can be seen. The lateral border of this triangle is the radial nerve itself (white arrow), and the medial research foundation with which they are affiliated have not border is the biceps tendon (blue arrow). The more proximal, the safer access will be. received any financial payments or other benefits from any commercial entity related to the subject of this article. Supplementary data To perform this portal, the patient must be placed in the supine position. The anterior portal cannot be performed in the lateral Supplementary data to this article can be found online at decubitus or prone position. The main advantages of the supine https://doi.org/10.1016/j.jseint.2023.02.012. position are: 1) it facilitates adding open surgical procedures, such as ulnar decompression; and 2) it facilitates access to the airway by References the anesthesiologist.2 However, access to the olecranon fossa is more uncomfortable in this position. Some authors propose leaving 1. Adolfsson L. Arthroscopy of the elbow joint: a cadaveric study of portal the upper extremity completely free for the access to the posterior placement. J Shoulder Elbow Surg 1994;3:53-61. 2. 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