[The risk of neurovascular damage in elbow joint arthroscopy. Which approach is better: anteromedial or anterolateral?]

Substantiation of safe and effective arthroscopic approaches to the elbow joint in case of enthesopathy of the distal humerus

Background: With the development of arthroscopic surgical techniques, diagnostic and therapeutic possibilities have significantly expanded, but they have not become widely used in everyday clinical practice in the treatment of elbow joint pathology. This is due to the small volume of the joint, the close location of the neurovascular formation and the complexity of manipulation. Elbow arthroscopy is a dynamic procedure with a change in the ratio of neurovascular structures and portals in different elbow positions. The risk of damage to neurovascular formations during arthroscopy of the elbow joint is up to 14%. Purpose: determination of the safest areas promising for the formation of arthroscopic approaches to the elbow joint in the treatment of patients with enthesopathy of the distal humerus.. Methods: To achieve this goal, a complex topographic- anatomical and clinical study was performed on 30 non-fixed anatomical preparations of the upper limb, which included 4 stages, where the topographic and anatomical features of the tendon-muscular and neurovascular structures forming the elbow joint were studied, depending on the angle of flexion of the elbow joint at 3 different levels: level I - 5 cm above the joint space, level II - joint space, level III - the neck of the radius, additionally the above structures were studied using MRI studies in 30 patients. Results: When the elbow joint is flexed to 90, the brachial artery at level I moves away from the bone and is located at a distance from 27,8 (27.7-28,1) mm to 28,6 (28,4-28,7). The radial nerve at the II level from СMEL is located at 16,4 (16,5-18,8) mm. Median nerve from СMEL by 17,5 (16,6-18,1) mm. The brachial artery is 23,7 (20,522,8) mm distant from the СMEL. The anterior bundle of the MCL has: an average proximal width of 6,2 1,4 mm, an average width of the middle part of 6,5 1,5 mm, an average distal width of 9,3 1,4 mm. The average area of attachment on the medial epicondyle of the humerus is 45,5 9,3 mm, it has a rounded shape. The radial collateral ligament has an average length of 20,5 1.9 mm and a bundle width of 5,2 0,8mm. The average area of attachment on the humerus is 13,6 mm. The average area of ECRB on the lateral epicondyle of the humerus was 53,1 3,7mm. The mean area of the FCR on the medial epicondyle was 58,3 6.3mm. The distance from the entrance of the deep branch of the radial nerve to the canalis sapinatorius to the joint space is 28 (25,529,6) mm. Conclusion: The results of this study allow the operating surgeon to decide on the choice and placement of arthroscopic access to the elbow joint, which in turn helps to minimize the risk of damage to neurovascular structures.

Far Anterior Medial Portals in Complicated Elbow Arthroscopic Procedures: Safety Profile in a Cadaveric Model

Purpose

The purpose of this study is to describe the placement and evaluate the safety of the far anterior proximal and distal anteromedial portals by comparing them to previously defined portal techniques in a cadaveric model of the elbow.

Methods

Six paired (left and right) fresh, frozen cadaveric elbow joints were dissected. .62-mm Kirschner wires were placed at the literature-defined distal and proximal portal sites on right elbows. The proposed “far anterior” distal and proximal portals were established on the matched left elbows. The elbows were dissected to display the median and ulnar nerves. Digital calipers were used to measure distances from wires to nerves.

Results

For the distal portal, the literature-defined portals were a significantly greater distance (P = .014) from the ulnar nerve (31.22 mm) compared to the far anterior portals (24.65 mm). For the proximal portal, the far anterior portals were a significantly greater distance (P = .026) from the ulnar nerve (26.98 mm) than the literature-defined portals (13.75 mm). There was no significant difference between the far anterior and literature-defined proximal and distal portal techniques in relation to the median nerve.

Conclusions

Analysis of elbow arthroscopy anteromedial portal technique shows the far, anterior, proximal, and distal portals are a safe distance from the ulnar and median nerves. A portal modification that may address complicated elbow conditions is a more anterior placement of the medial portals to allow for better visualization and access.

Clinical Relevance

The elbow is a difficult joint in which to perform arthroscopic surgery. One option our institution has used for safe portal modification to address complicated elbow conditions is a further anterior placement of the medial portals to allow better visualization and access.

Anatomic relations of the median nerve to the ulnar insertion of the brachialis muscle: safety issues and implications for medial approaches to the elbow joint

INTRODUCTION

Preventing nerve injury is critical in elbow surgery. Distal extension of medial approaches, required for coronoid fracture fixation and graft-replacement, may endanger the median nerve. This study aims to describe an easily identifiable and reproducible anatomical landmark to localize the median nerve distal to the joint line and to delineate how its relative position changes with elbow flexion and forearm rotation.

MATERIALS AND METHODS

The median nerve and the ulnar insertion of the brachialis muscle were identified in eleven fresh-frozen cadaveric specimens after dissection over an extended medial approach. The elbow was brought first in full extension and then in 90° flexion, and the shortest distance between the two structures was measured while rotating the forearm in full pronation, neutral position and full supination.

RESULTS

The distance between the median nerve and the brachialis insertion was highest with the elbow flexed and the forearm in neutral position. All distances measured in flexion were larger than those in extension, and all distances measured from the most proximal point of the brachialis insertion were larger than those from the most distal point. Distances in pronation and in supination were smaller than to those in neutral forearm position.

CONCLUSIONS

The ulnar insertion of the brachialis is a reliable landmark to localize and protect the median nerve at the level of the coronoid base. Elbow flexion and neutral forearm position increase significantly the safety margins between the two structures; this information suggests some modifications to the previously described medial elbow approaches.

LEVEL OF EVIDENCE

Basic Science Study.

Safety of Anteromedial Portals in Elbow Arthroscopy: A Systematic Review of Cadaveric Studies

PURPOSE

To systematically review available literature comparing location and safety of 2 common anteromedial portals with nearby neurovascular structures in cadaveric models and to determine the correct positioning and preparation of the joint before elbow arthroscopy.

METHODS

The review was devised in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Inclusion criteria consisted of original, cadaveric studies performed by experienced surgeons on male or female elbows evaluating anteromedial portal placement with regard to proximity of the arthroscope to neurovascular structures. Exclusion criteria consisted of case reports, clinical series, non-English language studies, and noncadaveric studies. Statistical analysis was done to measure reviewer reliability after scoring of each study.

RESULTS

During screening, 2,596 studies were identified, and 10 studies met final inclusion as original, cadaveric investigations of anteromedial portal proximity to neurovascular structures. The difference in distance between proximal and distal portals was <1 mm for the brachial artery and <1.5 mm for the medial antebrachial cutaneous nerve, whereas the ulnar nerve was 4.17 mm further from the distal portal and the median nerve was 5.07 mm further from the proximal portal. Joint distension increased the distances of neurovascular structures to portal sites, with the exception of the ulnar nerve in distal portals. Elbow flexion to 90° increased distances of all neurovascular structures to portal sites.

CONCLUSION

The results show that the proximal anteromedial portal puts fewer structures at risk compared with the distal portal. Elbows in 90° flexion with joint distension carry a lower risk for neurovascular injury during portal placement. These findings suggest the proximal anteromedial portal to be the safer technique in anteromedial arthroscopy of the elbow.

CLINICAL RELEVANCE

Discrepancies in placement of portals have existed in the literature, indicating differing safety margins regarding surrounding neurovascular anatomy. The present study aims to link together the literature-based evidence to describe the safest anteromedial portal variation.

Modified Anterolateral Portals in Elbow Arthroscopy: A Cadaveric Study on Safety

PURPOSE

To evaluate the proximity to the radial nerve on cadaveric specimens of 2 modified anterolateral portals used for elbow arthroscopy.

METHODS

Ten fresh cadaveric elbow specimens were prepared. Four-millimeter Steinman pins were inserted into 3 anterolateral portal sites in relation to the lateral epicondyle: (1) the standard distal anterolateral portal, (2) a modified direct anterolateral portal, and (3) a modified proximal anterolateral portal. These were defined as follows: direct portals 2 cm directly anterior to the lateral epicondyle, and proximal portals 2 cm proximal and 2 cm directly anterior to the lateral epicondyle. Each elbow was then dissected to reveal the course of the radial nerve. Digital photographs were taken of each specimen, and the distance from the Steinman pin to the radial nerve was measured.

RESULTS

The modified proximal anterolateral and direct anterolateral portals were found to be a statistically significant distance from the radial nerve compare to the distal portal site (P = .011 and P = .0011, respectively). No significant difference was found in the proximity of the radial nerve between the modified proximal and direct anterolateral portals (P = .25). Inadequate imaging was found at a single portal site for the proximal site; 9 specimens were used for analysis of this portal with 10 complete specimens for the other 2 sites.

CONCLUSIONS

In cadaveric analysis, both the modified proximal and direct lateral portals provide adequate distance from the radial nerve and may be safe for clinical use. In this study, the distal anterolateral portal was in close proximity of the radial nerve and may result in iatrogenic injury in the clinical setting.

CLINICAL RELEVANCE

This is a cadaveric analysis of 2 modified portal locations at the anterolateral elbow for use in elbow arthroscopy. Further clinical studies are needed prior to determining their absolute safety in comparison to previously identified portal sites.

Portal placement in elbow arthroscopy by novice surgeons: cadaver study

PURPOSE

In this anatomical cadaver study, the distance between major nerves and ligaments at risk for injury and portal sites created by trainees was measured. Trainees, inexperienced in elbow arthroscopy, have received a didactic lecture and cadaver instruction prior to portal placement. The incidence of iatrogenic injury from novice portal placement was also determined.

METHODS

Anterolateral, direct lateral, and anteromedial arthroscopic portals were created in ten cadavers by ten inexperienced trainees in elbow arthroscopy. After creating each portal, the trajectory of the portal was marked with a guide pin. Subsequently, the cadavers were dissected and the distances between the guide pin in the anterolateral, direct lateral, and anteromedial portals and important ligaments and nerves were measured.

RESULTS

The difference between the distance of the direct lateral portal and the posterior antebrachial cutaneous nerve (PABCN) (22 mm, p < 0.001), the lateral antebrachial cutaneous nerve (4.0 mm, p < 0.001), and the radial nerve (25 mm, p < 0.001) was different from the average reported distances in the literature. A difference was found between the distance of the anterolateral portal and the PABCN (32 mm, p < 0.001) compared to previous studies. Three major iatrogenic complications were observed, including: laceration of the posterior bundle of the medial ulnar collateral ligament, lateral ulnar collateral ligament midsubstance laceration, and median nerve partial laceration.

CONCLUSION

Surgeons increasingly consider arthroscopic treatment as an option for elbow pathology. In the present study a surgical complication rate of 30 % was found with novice portal placement during elbow arthroscopy. Furthermore, as the results from this study have indicated, accurate, precise, and safe portal placement in elbow arthroscopy is not easily achieved by didactic lecture and cadaver instruction session alone. Level of evidence V.

Elbow Positioning and Joint Insufflation Substantially Influence Median and Radial Nerve Locations

BACKGROUND

The median and radial nerves are at risk of iatrogenic injury when performing arthroscopic arthrolysis with anterior capsulectomy. Although prior anatomic studies have identified the position of these nerves, little is known about how elbow positioning and joint insufflation might influence nerve locations.

QUESTIONS/PURPOSES

In a cadaver model, we sought to determine whether (1) the locations of the median and radial nerves change with variation of elbow positioning; and whether (2) flexion and joint insufflation increase the distance of the median and radial nerves to osseous landmarks after correcting for differences in size of the cadaveric specimens.

METHODS

The median and radial nerves were marked with a radiopaque thread in 11 fresh-frozen elbow specimens. Three-dimensional radiographic scans were performed in extension, in 90° flexion, and after joint insufflations in neutral rotation, pronation, and supination. Trochlear and capitellar widths were analyzed. The distances of the median nerve to the medial and anterior edge of the trochlea and to the coronoid were measured. The distances of the radial nerve to the lateral and anterior edge of the capitulum and to the anterior edge of the radial head were measured. We analyzed the mediolateral nerve locations as a percentage function of the trochlear and capitellar widths to control for differences regarding the size of the specimens.

RESULTS

The mean distance of the radial nerve to the lateral edge of the capitulum as a percentage function of the capitellar width increased from 68% ± 17% in extension to 91% ± 23% in flexion (mean difference = 23%; 95% confidence interval [CI], 5%-41%; p = 0.01). With the numbers available, no such difference was observed regarding the location of the median nerve in relation to the medial border of the trochlea (mean difference = 5%; 95% CI, -13% to 22%; p = 0.309). Flexion and joint insufflation increased the distance of the nerves to osseous landmarks. The mean distance of the median nerve to the coronoid tip was 5.4 ± 1.3 mm in extension, 9.1 ± 2.3 mm in flexion (mean difference = 3.7 mm; 95% CI, 2.04-5.36 mm; p < 0.001), and 12.6 ± 3.6 mm in flexion and insufflation (mean difference = 3.5 mm; 95% CI, 0.81-6.19 mm; p = 0.008). The mean distance of the radial nerve to the anterior edge of the radial head increased from 4.7 ± 1.8 mm in extension to 7.7 ± 2.7 mm in flexion (mean difference = 3.0 mm; 95% CI, 0.96-5.04 mm; p = 0.005) and to 11.9 ± 3.0 mm in flexion with additional joint insufflation (mean difference = 4.2 mm; 95% CI, 1.66-6.74 mm; p = 0.002).

CONCLUSIONS

The radial nerve shifts medially during flexion from the lateral to the medial border of the inner third of the capitulum. The median nerve is located at the medial quarter of the joint. The distance of the median and radial nerves to osseous landmarks doubles from extension to 90° flexion and triples after joint insufflation.

CLINICAL RELEVANCE

Elbow arthroscopy with anterior capsulectomy should be performed cautiously at the medial aspect of the joint to avoid median nerve lesions. Performing arthroscopic anterior capsulectomy in flexion at the lateral aspect of the joint and in slight extension at the medial edge of the capitulum could enhance safety of this procedure.

Elbow Positioning and Joint Insufflation Substantially Influence Median and Radial Nerve Locations

BACKGROUND

The median and radial nerves are at risk of iatrogenic injury when performing arthroscopic arthrolysis with anterior capsulectomy. Although prior anatomic studies have identified the position of these nerves, little is known about how elbow positioning and joint insufflation might influence nerve locations.

QUESTIONS/PURPOSES

In a cadaver model, we sought to determine whether (1) the locations of the median and radial nerves change with variation of elbow positioning; and whether (2) flexion and joint insufflation increase the distance of the median and radial nerves to osseous landmarks after correcting for differences in size of the cadaveric specimens.

METHODS

The median and radial nerves were marked with a radiopaque thread in 11 fresh-frozen elbow specimens. Three-dimensional radiographic scans were performed in extension, in 90° flexion, and after joint insufflations in neutral rotation, pronation, and supination. Trochlear and capitellar widths were analyzed. The distances of the median nerve to the medial and anterior edge of the trochlea and to the coronoid were measured. The distances of the radial nerve to the lateral and anterior edge of the capitulum and to the anterior edge of the radial head were measured. We analyzed the mediolateral nerve locations as a percentage function of the trochlear and capitellar widths to control for differences regarding the size of the specimens.

RESULTS

The mean distance of the radial nerve to the lateral edge of the capitulum as a percentage function of the capitellar width increased from 68% ± 17% in extension to 91% ± 23% in flexion (mean difference = 23%; 95% confidence interval [CI], 5%-41%; p = 0.01). With the numbers available, no such difference was observed regarding the location of the median nerve in relation to the medial border of the trochlea (mean difference = 5%; 95% CI, -13% to 22%; p = 0.309). Flexion and joint insufflation increased the distance of the nerves to osseous landmarks. The mean distance of the median nerve to the coronoid tip was 5.4 ± 1.3 mm in extension, 9.1 ± 2.3 mm in flexion (mean difference = 3.7 mm; 95% CI, 2.04-5.36 mm; p < 0.001), and 12.6 ± 3.6 mm in flexion and insufflation (mean difference = 3.5 mm; 95% CI, 0.81-6.19 mm; p = 0.008). The mean distance of the radial nerve to the anterior edge of the radial head increased from 4.7 ± 1.8 mm in extension to 7.7 ± 2.7 mm in flexion (mean difference = 3.0 mm; 95% CI, 0.96-5.04 mm; p = 0.005) and to 11.9 ± 3.0 mm in flexion with additional joint insufflation (mean difference = 4.2 mm; 95% CI, 1.66-6.74 mm; p = 0.002).

CONCLUSIONS

The radial nerve shifts medially during flexion from the lateral to the medial border of the inner third of the capitulum. The median nerve is located at the medial quarter of the joint. The distance of the median and radial nerves to osseous landmarks doubles from extension to 90° flexion and triples after joint insufflation.

CLINICAL RELEVANCE

Elbow arthroscopy with anterior capsulectomy should be performed cautiously at the medial aspect of the joint to avoid median nerve lesions. Performing arthroscopic anterior capsulectomy in flexion at the lateral aspect of the joint and in slight extension at the medial edge of the capitulum could enhance safety of this procedure.