Pectoral Implants

Anatomy and Physiology

The pectoralis muscle is a thick, broad, fan-shaped muscle situated on the chest underneath the breast. The primary function of this muscle is adduction, internal rotation, and flexion of the humerus. It originates on the medial half of the clavicle, the anterior surface of the sternum, and the superior six costal cartilages, and inserts on the bicipital groove of the humerus. The pectoralis major muscle receives innervation from the lateral and the medial pectoral nerves, while the medial pectoral nerve innervates the pectoralis minor muscle.

In two-thirds of patients, the medial pectoral nerve courses through the pectoralis minor to innervate the lower portion of the pectoralis major, while in one-third of patients, this nerve courses along the lateral aspect of the pectoralis minor. The lateral pectoral nerve runs under the pectoralis major muscle to innervate the proximal portion of this muscle. Given these anatomic relationships, dissection between the two pectoralis muscles can cause partial denervation of the pectoralis major.

Poland Syndrome is a condition in which some or all of the pectoralis muscle is absent on one side. Other causes of a deformed pectoralis muscle include denervation injury or muscle tears after excessive training.[1][3][4]

Indications

A patient is a candidate for pectoral implants if he desires an enhancement of the bulk or projection of his chest; this could be due to lack of exercise, congenital absence of all or part of the pectoralis muscle, or deformity due to an existing injury.[1][3]

Contraindications

Male patients with unrealistic expectations about what pectoral augmentation can achieve should receive counsel, and clinicians should turn away those with muscle dysmorphia or body dysmorphic disorder if they will likely not be satisfied with the result.[1][5]

Equipment

Surgeons will often have multiple sizes and shapes of implants available. For the surgical procedure, a blunt dissector is necessary to develop a sub-pectoral plane for implant placement. Otherwise, a standard surgical suite and instrumentation are adequate for this procedure. Drains are not standard and are not needed.[3][5][6]

Personnel

The surgeon will often benefit from a trained assistant to help with retraction during the case; this is at the discretion of the surgeon. As this procedure takes place under general anesthesia, an anesthesiologist is also required.[3][5][6]

Preparation

Before surgery, implant size and shape must be selected with the patient. First, the pectoral muscle is measured as follows: the width at the lower border and infra-clavicular border of muscle, the height at the midportion of muscle, and the distance between the chondrosternal angle and the axilla. With these dimensions, an implant volume is selected that will achieve the patient’s desires for a larger, more proportional chest.

The pocket for implant placement tends to be about 2 cm smaller than these measurements. If the reconstruction is unilateral, the surgeon must make attempts to match the implant to the contralateral side. If the implant is custom-made, a cast can be used to create the implant.

The patient should also understand the risks, benefits, and alternatives of the procedure to make an informed decision. He should also be made aware of the expected postoperative course and limitations following the procedure.[3][5][6][7]

Technique or Treatment

Markings are made with the patient standing. Marking the borders of the pectoralis muscle will assist in determining the extent of sub-pectoral dissection. The incision to be used for implant placement is in the axillary fold. It is curvilinear in shape, parallels a skin crease, and is 4.5 to 6.0 cm long.  

Prior to the incisions, the axilla should be shaved using an electric shaver to minimize skin trauma. The patient is then placed supine and arms abducted out to 90 degrees. After the patient's skin is prepped and draped, an anesthetic solution with epinephrine is then infiltrated in the area of the incision. The incision is made, and the dissection is carried down until reaching the lateral tendon of the pectoralis muscle. At this point, the dissection changes to the submuscular plane - first using sharp dissection and then using a long, blunt dissector, which can be facilitated using a fiberoptic light retractor. The extent of the submuscular plane should mirror the previously-made external markings.

It is critical that the dissection is carried no more than 1 to 2 cm below the areola and that no sternal or pectoralis insertions become disrupted, as this can give the patient feminine-appearing breasts. Meticulous hemostasis is necessary to avoid potential hematoma formation. The pocket is soaked in either triple antibiotic solution or betadine and allowed to sit while performing the contralateral dissection. The implants are then placed through the incision, taking care to avoid contact with the skin as much as reasonable to avoid possible contamination. The patient must sit up to confirm symmetry. A multi-layered closure is then performed. It is up to the discretion of the plastic surgeon and the anesthesiologist if they wish to perform a medial and lateral pectoral nerve block after the procedure to help minimize post-operative pain.

A light compressive dressing is recommended for about a month, after which time the patient can discontinue this and begin mild physical activity. Surgeons do not typically utilize drains in this procedure.[1][5][6][7][8]

Complications

Complications after pectoral implantation are similar to those for breast augmentation. These include bleeding or hematoma formation, infection, poor cosmetic outcome, asymmetry, shifting or rotation of the implant, seroma, implant rupture, capsular contracture, and poor scarring. Any time implant placement is under the pectoralis muscle, the patient may develop muscle spasm. This condition can be treated with muscle relaxers, or for persistent spasms, botulinum toxin can be a possible treatment modality.   

Other less common complications include anesthetic complications and resulting paresthesia of the inner arm. Although there are no reports of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) with pectoral implants, they have a textured surface, which can theoretically cause this rare condition.[1][9][10]

Clinical Significance

Pectoral implants have been in use for over 30 years in both the cosmetic and reconstructive realms of plastic surgery. Whether used to treat a congenital or acquired chest wall asymmetry, or to enhance the appearance of the chest, pectoral implants are an essential component in the plastic surgeon's armamentarium. They not only enhance the appearance but also the self-image of those who receive them.[1][3]

Enhancing Healthcare Team Outcomes

Pectoral implant placement is a procedure that can be associated with many complications, of which one is a poor cosmetic outcome and patient dissatisfaction with the result, which can lead to prolonged patient and surgeon distress, and lead to an increase in healthcare costs. It is, therefore, imperative to identify the risk factors for patient dissatisfaction and perform a thorough assessment of the patient before any surgery. A team approach is an ideal way to limit the complications of this procedure. Prior to surgery, the patient should have the following done:

• Psychological evaluation to ensure reasonable patient expectations and an optimized aesthetic result
• Fully informed consent is necessary when discussing the risks, benefits, and alternatives of the procedure to make an informed decision, and also be made aware of the expected postoperative course and limitations following the procedure.
• Seen by an anesthesiologist to ensure the patient is safe for general anesthesia[1][5] [Level 5]