Читать книгу Atlas of Orthopaedic Surgical Exposures - Christopher Jordan - Страница 15

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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

The major trick with this approach is feeling the acromioclavicular joint and paralleling the incision over the top of it. It is important to remember that the acromioclavicular joint is not always exactly vertical. It will sometimes angle in a medial or lateral direction, as it goes superiorly. If you do not find the joint with an initial attempted opening of the capsule, you can identify it with a needle. That will tell you where it is located. You would then reflect your capsule in that direction until you can see the joint. If you are approaching the coracoacromial ligament or the coracoclavicular ligament, it is important to reflect the deltoid subperiosteally so that its reattachment is more effective. Once that is reflected, you lift it anteriorly, which will show the underlying ligaments.

HOW TO TELL IF YOU ARE LOST

It is practically impossible to get lost with this approach. If you are too far anterior, you will see the fibers of the deltoid. If you are too far posterior, you will see the fibers of the trapezius coming in from the back. If you are too far lateral, again you will run into the fibers of the deltoid as they approach the lateral acromion. If you are too far medial, you will see the shaft of the clavicle.

Once you are deep to the deltoid muscle, again it is difficult to get lost posteriorly because you will simply run into the clavicle. It is possible to be too far medial or lateral. It is very dangerous to be too far medial because the vascular structures are quite close to the clavicle medial to the coracoid. If you see anything that looks like a blood vessel, you are lost medially. If you are more than 2 cm lateral to the acromioclavicular joint while underneath the deltoid, you are lost laterally. The coracoid is actually medial to the acromioclavicular joint.

FIGURE 6–1 The skin incision, which is an incision paralleling the acromioclavicular joint over the top of the joint. It is typically centered over the joint and is usually 4 or 5 cm in length.

FIGURE 6–2 The subcutaneous fat.

FIGURE 6–3 The transverse fibers of the dorsal capsule of the acromioclavicular joint.

FIGURE 6–4 The capsule open, exposing the acromioclavicular joint.

Deltoid

Capsule

Acromioclavicular Joint

Clavicle

Acromion

Coracoacromial Ligament

Coracoid

Coracoclavicular Ligament

Coracoacromial Ligament from Base of Coracoid (this is an anatomic variant)

FIGURE 6–5 The anterior extension of this approach, if you were going to go down to the coracoid for a reconstruction of the coracoclavicular ligament. The deltoid is seen attaching to the clavicle.

FIGURE 6–6 The coracoacromial ligament running transversely across the approach. The deltoid muscle has been dissected off of the clavicle and is retracted anteriorly.

FIGURE 6–7 The coracoid just at the end of the retractor. The acromioclavicular joint is at the top.

FIGURE 6–8 The coracoacromial ligament running transversely, and the coracoclavicular ligament on the edge of the picture, running up toward the clavicle. The prominence in the picture is the tip of the coracoid process itself.