2015 ISAKOS Biennial Congress ePoster #2315

Arthroscopic Latarjet: Is the Trans-Pec Portal Safe? An Anatomic Study and Description of a Safe Zone for the Clinician

Albert Dunn, DO, Cos Cob, CT UNITED STATES
Stephanie C. Petterson, MPT, PhD, Old Greenwich, CT UNITED STATES
Kevin D. Plancher, MD, MPH, New York, NY UNITED STATES

Orthopaedic Foundation, Stamford, Connecticut, USA

FDA Status Not Applicable

Summary: The trans-pectoralis major (East) portal, critical to the success of all-arthroscopic Latarjet, does not pose risk to any neurovascular structures when placed in a safe zone 45-50mm distal and 30-35mm medial to the coracoid.

Rate:

Abstract:

Background

Safety when performing the arthroscopic Bankart-Bristow Latarjet procedure is essential. The Trans-Pectoralis Major (East) portal is critical to the success of the All-Arthroscopic Latarjet (AAL). AAL has a lower recurrence rate than open Latarjet, however, complications including coracoid non-union and brachial plexus injury have slowed its acceptance universally. The purpose of this study was to describe a safe zone for East portal placement.

Methods

Twelve shoulder (six match-paired, fresh-frozen, cadaveric torsos) sectioned to T7 were utilized. Specimens were mounted in the modified beach chair position. Standard Posterior, Central (lateral to the coracoid), West (3.5cm horizontally lateral to the coracoid), and East (inferior/medial to the coracoid) portals were created. A 90mm, 20-gauge spinal needle was passed through the East portal and traversed the pectoralis major musculature, superficial to the conjoined tendon and pectoralis minor. Visualization was accomplished via the West portal. A second needle was directed toward the medial base of the coracoid, penetrating pectoralis minor. Superficial and deep plane dissections were performed. Distance measurements were made with calipers accurate to 0.01mm. A paired T-test analyzed interlimb differences.

Results

In the superficial plane, the cephalic vein and lateral pectoral nerve were mean distances of 4.63±1.91mm and 9.36±2.60mm from the needle. In the deep plane, the axillary nerve was 24.87±7.39mm, lateral brachial plexus cord 25.49±8.07mm, axillary artery 34.13±6.05mm, and musculocutaneous nerve 42.22±9.20mm from the needle. There were no statistically significant interlimb differences (p>0.05) A safe starting point was consistently 45-50mm distal and 30-35mm medial to the coracoid, a minimum distance of 10mm to the lateral pectoral nerve. The arthroscopic procedure was performed on one shoulder with an open dissection revealing a variation of the axillary nerve unharmed utilizing our described safe zone.

Conclusion

The East portal does not pose risk to neurovascular structures and is safe for use when performing an AAL. This portal allows excellent access for the bone block to hopefully avoid non-union without compromise to any neurovascular structures. Post-surgical variation was noted for the axillary nerve; surgeons should be aware in a revision setting for both open and arthroscopic coracoid transfers.