Deltopectoral Approach: Superficial Dissection


- See:  Anterior Approach to the Shoulder and Total Shoulder Arthroplasty

- Incision:
    - deltopectoral internval separates plane between axillary innervation (deltoid) and lateral and medial pectoral innervation to pectoralis major (incision should stay just lateral to the axillary skin crease);
    - ensure that the shoulder is position in neutral rotation and slight abduction;
             - if this is not taken into consideration, the distal incision may be placed too far laterally;
    - incision begins below middle of clavicle (or at AC joint), passes lateral to coracoid (or over it), and continues distally toward upper mid humerus (at deltoid tuberosity);
             - hence incision passes along lateral border of biceps and parallels the anterior aspect of the deltoid;
             - placing incision slightly lateral to the DP interval may minimize scarring, but distal limb of incision should end just medial to anterior insertion of deltoid;
                  - always avoid ending the incision lateral to the deltoid insertion;
           - extended deltopectoral incision, would continue distally as an anterior approach to the humerus;

                     


- Deltopectoral Interval:
    - the cephalic vein helps demarcate the deltopectoral interval;
    - cephalic vein
          - cephalic vein proceeds superiorly over the coracoid on its way to the subclavian vein;
          - if the cephalic vein is not visible, look for a fat strip which may overlie the vein; (may be located more superior than is often thought);
          - in most cases, the vein is retracted laterally (along w/ the deltoid) because it is usually more adherent to the deltoid (preserving the deltoid's venous drainage) and becuase deltoid branch of thoracoacromial artery lies parallel and lateral to cephalic vein and supplies blood to deltoid;
          - the easiest way to develop the deltopectoral interval is to dissect downward just medial to the cephalic vein;
                  - avoid the temptation of defining the interval between the superficial muscle fibers;
                  - often the true interval lies more lateral than is expected;
    - subdeltoid and subpectoral spaces:
          - these spaces need to be developed by blunt dissection down to their muscular insertions;
          - at times the medial edge of the deltoid is covered by clavi-pectoral fascia, in which case, it should be sharply transected, to allow entry to the sub-deltoid space;
          - in upper 1/3 of deltopectoral interval, branch of thoracoacromial artery is cauterized and transected;
          - at this point, a self retaining retraction can be insert beneath each muscle;
    - extensile measures:
          - generally the deltopectoral groove is opened distally until the insertion of the pectoralis is reached;
          - deltoid muscle:
                  - anterior 1/3 of the deltoid insertion may be elevated for further posterolateral exposure;
                  - on occassion, a small portion of the deltoid can be dissected off the clavicle, allowing flap of muscle to be reflected more laterally;
          - pectoralis muscle:
                  - incise the cephalad 1-3 cm of the pectoralis major tendon inorder to achieve better exposure of the inferior portion of the subscapularis tendon (and better protection of the axillary nerve);
                         - detaching the upper 1-2 cm of the pectoralis will also better visualize the inferior capsule & axillary nerve, which passes just inferior to the capsule;
                  - if the shoulder has a severe internal rotation contracture, consider release of the entire tendon;
                         - note that the remaining internal rotators are intact (latissimus, teres major, and subscapularis);
                  - use the long head of the biceps to help locate the insertion of the pectoralis (placing the arm in abduction and internal rotation may also help with exposure);
                         - the long head of the biceps emerges from the bicipital groove at a point just above the insertion of the pectoralis, and can be injured when the pectoralis insertion is partially incised;


- Deep Dissection:
    - clavipectoral fascial incision:
           - once the deltopectoral interval has been fully developed, the clavipectoral fascia is exposed (which is most prominent lateral to coracoid muscles);
           - clavipectoral fascia is differentiated from the deeper tissues, because it will not move with internal and external rotation;
           - tip of the coracoid and the conjoined tendon (short head of biceps and the coraco-brachialis) is identified;
           - clavipectoral fascia is then divided vertically just lateral to the conjoined tendon, up to coracoacromial ligament, exposing subscapularis tendon & lesser tuberosity;
                   - proximally, the fascia is divided at a point just lateral to the coracoid;
                   - the incision is carried distally to the level of the anterior circumflex;
                   - these vessels mark the level of the subscapularis tendon;
    - identification of the musculocutaneous nerve:
           - musculocutaneous nerve can usually be palpated on deep surface of coracobrachialis;
           - nerve enters posterior of coracobrachialis about 5 cm distal to coracoid tip but can be as close as 1 to 2 cm;
    - identification of the axillary nerve
    - retraction:
           - often a "Charnley type" of self retaining retractor is inserted underneath the deltoid medially and the coracobrachialis laterally;
    - coraco-acromial ligament:
           - in patients w/ traumatic arthritis or DJD, the shoulders may be tight and therefore, the ligament can be partially incised for better exposure of the upper portion of the subscapularis;
           - in patients w/ rheumatoid arthritis or cuff tear arthropathy, excision of the CA ligament may destabilize the shoulder arthroplasty



- Deep Exposure for Total Shoulder Arthroplasty



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, January 3, 2013 12:12 pm