Deltoid split approach
1. Indications
The deltoid split (or transdeltoid lateral or anterolateral) approach can be used for various treatments of proximal periprosthetic humeral fractures where limited access to the joint is required.
This approach is especially useful for osteosynthesis of fractures of the greater tuberosity.
This incision is placed between the clavicular part (1) and the acromial part (2) of the deltoid muscle, as illustrated.
Depending on the fracture morphology and planned osteosynthesis, the extensions of the skin incision may vary, but should not extend more than 5 cm distally to the acromion to protect the axillary nerve.
This approach can be performed to treat periprosthetic fractures around anatomic prostheses.
2. Anatomy
Neurovascular structures
The course of the axillary nerve must be kept in mind.
3. Skin incision
Anatomical landmarks
Anatomical landmarks for the transdeltoid lateral approach are:
A) The lateral border of the acromion
B) The lateral side of the proximal humeral shaft
Both landmarks can be palpated easily.
Axillary nerve
Before incising the skin, mark the distal limit of the approach, 5cm below the acromion.
If a plate is to be passed underneath the axillary nerve, as in minimally invasive plate osteosynthesis (MIO), mark a second line 5 cm distal to the first, below which the axillary nerve should not be encountered. The space between these two lines is the danger zone on the lateral humerus.
Skin incision
Make a skin incision from the lateral border of the acromion 5 cm distally, parallel to the axis of the humerus.
The skin incision can be adjusted more anteriorly or posteriorly depending on the fracture pattern.
4. Exposure of the middle third part of the deltoid muscle
Expose the raphe between the clavicular and acromial parts of the deltoid muscle and split the muscle between its fibers.
For maximum exposure, split the deltoid up to the margin of the acromion, but do not split it distally more than 4.5 cm from its origin to avoid damaging the axillary nerve and paralyzing the anterior part of the deltoid.
Palpate the axillary nerve on the deep surface of the deltoid muscle, distal to the incision. This nerve encircles the proximal humerus a little less than halfway from the lateral margin of the acromion to the insertion of the deltoid muscle.
5. Wound closure
After surgery, irrigate the wound. Some surgeons place a drain beneath the deltoid muscle.
The subcutaneous fascia and the skin are closed in layers.
