Saturday, February 06, 1999
"Visualization improved over our prior use of a posterior approach," said study co-author John C. Torris, MD, department of orthopaedics, National Naval Medical Center, Bethesda, Md.
In all of the cases, the trapezius was reattached with bone sutures and healed without complication.
"Suprascapular neuropathy is an uncommon diagnosis with a surgical treatment usually involving an anterior or posterior approach," Dr. Torris said. "Difficulty with adequate visualization of the nerve using these approaches prompted us to develop a superior approach."
Dr. Torris and his colleagues described the typical surgical approach where patients are in the beach chair position, and the incision begins over the lateral scapular spine and curves anteriorly over the acromion to the acromioclavicular joint and lateral clavicle. Next, the trapezius muscle is detached subperiosteally from the lateral scapula and acromion, and it is retracted medially. The supraspinatus muscle is carefully retracted either anteriorly or posteriorly as needed to allow for visualization of the suprascapular nerve from the proximal to the suprascapular notch to the spinoglenoid notch.
The orthopaedists performed the surgical procedure on 20 fresh cadaver shoulders, and measured the dimensions of the suprascapular nerve exposure. Visualization and manipulation of the nerve was possible at an average of 3.0 centimeters (range: 2.0 to 3.9 centimeters) proximal to the suprascapular notch. An average of 3.5 centimeters (range: 4.1 to 3 centimeters) was not visualized from the upper trunk to the proximal limit of surgical exposure. Exposure of the nerve from the suprascapular notch to the spinglenoid notch measured an average of 2.7 centimeters (range: 2.1 to 3.8 centimeters) in length.
In all of the cadaver specimens, the suprascapular nerve passed under the suprascapular ligament. "The nerve split into two branches to the supraspinatus in 95 percent of the specimens, and a trifurcation in five percent," Dr. Torris said.
Co-authors of the study, all from the department of orthopaedics, National Naval Medical Center, Bethesda, Md., are Elizabeth A. Moran, MD; Scott P. Steinmann, MD; James E.B. Stuart, MD; and Shawn F. Taylor, MD.