move slightly medially until you can feel the ligament overlying the suprascapular notch. This ligament is frequently covered with fat. If there is a large amount off at between the two muscles, then remove it or retract it so you can see the supraspinatus and the suprascapular ligament. Remember that the artery will sometimes pass on top of the ligament, whereas the nerve will be below it.
Once the ligament is identified, it can be transected with a scalpel or, for better control, a Kerrison rongeur can be used.
TRICKS
The major trick to this approach is to identify the interval between the trapezius and the supraspinatus. There is usually fat between these two muscles, and the fiber orientation is different.
The second trick is to feel the base of the coracoid and then go medial to that to feel the suprascapular notch. Finally, be aware of the fact that the artery may cross over the top of the ligament, and take care not to injure it.
HOW TO TELL IF YOU ARE LOST
It is hard to get lost inferiorly with this approach because the incision starts above the spine of the scapula, and the spine is easily palpable.
It is possible to be too far medial or lateral. If your goal is to free up the suprascapular notch, it is important to realize it is approximately 1 cm medial to the coracoid base, so that the approach can be adjusted once you are deep to the trapeziusand the coracoid base is then palpable.
It is also possible to be too deep and separate the supraspinatus muscle off of the spine of the scapula and its fossa along with the trapezius. Coming in underneath the supraspinatus muscle does put the suprascapular nerve at risk. It is important, therefore, to clearly identify the plane between the trapezius and the supraspinatus. The fiber orientation is different for the two muscles, and so if you see fibers running straight medial to lateral, you are looking at the supraspinatus, not the trapezius.
FIGURE 5–1 The skin incision superior to the spine of the scapula.
FIGURE 5–2 The trapezius muscle approaching the spine of the scapula.
FIGURE 5–3 The spine of the scapula and the trapezius muscle being separated from it. Note that there is a large amount of fat beneath the trapezius, which is usually a good clue to the interval between the trapezius and the supraspinatus.
FIGURE 5–4 The fat cleared out of the way. The trapezius is retracted anteriorly. The muscle belly of the supraspinatus is clearly visible.
FIGURE 5–5 The supraspinatus being held in a posterior direction. The trapezius is retracted anteriorly. The suprascapular ligament is clearly visualized. Note the artery coming over the top of the ligament.
FIGURE 5–6 The view after the ligament has been cut. The suprascapular nerve is clearly visible now that the ligament has been transected.
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ACROMIOCLAVICULAR JOINT APPROACH
USES
This approach is used only to access the acromioclavicular joint for lateral clavicle resection or for acromioclavicular joint repair.
ADVANTAGES
The approach comes directly down on the area of interest through an area that has no significant neurovascular structures.
DISADVANTAGES
This is a limited-exposure approach that is difficult to extend in a medial direction, if that is needed.
STRUCTURES AT RISK
There are no significant structures at risk if this approach is done properly. If you are operating too inferior to the joint, the deltoid muscle and its attachment to the clavicle could be damaged.
TECHNIQUE
A 4-cm incision is made starting approximately 1 cm posterior to the acromioclavicular joint and coming anteriorly, paralleling the joint surface and directed toward the coracoid. It is carried through the subcutaneous tissue. The deltoid fibers will be seen approaching the clavicle. At that point, the transverse fibers of the capsule should be visible and the location of the joint can be identified. If the goal of surgery is to resect the lateral clavicle, there is no need for any further anterior dissection. Split the capsule fibers in line with their fibers along the superior clavicle and strip subperiosteally off the lateral clavicle so that it can be resected for a distance of 1 cm. This will create a flap of periosteum attached to the trapezius and another to the deltoid, simplifying closure.
If there is an acromioclavicular joint separation and the goal is to repair that, then the first structure identified will usually be the lateral end of the clavicle because it is protruding superiorly. In this case also the capsule will be torn. For these patients, you need to strip the deltoid off of the anterior clavicle for a distance of approximately 3 cm, which then allows you to see the coracoacromial ligament, which in turn should lead you to the coracoid. In these patients, the coracoclavicular ligaments will be torn, but they would normally be coming off of the superior medial side of the coracoid. If your repair includes some ligature under the coracoid and around the clavicle, then the deltoid needs to be stripped off the clavicle for a distance of 1 or 2 cm medial to the coracoid. The coracoid should be approached directly and you should stay subperiosteal on the coracoid and be very cautious anytime you are on the medial side of the coracoid. This exposure will also allow you to resect the coracoacromial ligament off the acromion if it is going to be used in the repair of the acromioclavicular joint.
TRICKS
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