Why are breast implants now commonly placed submuscular (under the pectoralis major) rather than subglandular?

Breast Implant Placement: Submuscular vs. Supramuscular

The traditional submuscular (subpectoral) placement of breast implants has been the standard approach for decades, but there is a growing shift toward supramuscular (prepectoral/subglandular) placement in appropriately selected patients due to elimination of animation deformity, more natural breast shape, and reduced postoperative pain—though this requires adequate soft tissue coverage to avoid complications.

Historical Context: Why Submuscular Became Standard

The submuscular approach became dominant in breast reconstruction and augmentation because:

• Reduced capsular contracture rates compared to early subglandular techniques 1
• Better implant coverage in patients with thin soft tissue, reducing visibility and palpability 2
• Lower rippling visibility over the superior pole of the breast 2
• Protection during radiation therapy in reconstruction cases, though this still carries significant contracture risk 1

Major Drawbacks of Submuscular Placement

The submuscular approach has several significant limitations that drive the current shift:

Animation deformity

• 100% of patients experience unwanted breast movement with pectoralis major muscle contraction during arm and shoulder movements 3
• This creates unnatural breast distortion, malposition, and asymmetry that worsens with muscle strength 2, 3
• The deformity is directly related to muscle strength and inversely related to breast tissue volume 2

Implant malposition

• 94% upward migration rate at 7-year follow-up even after initially appropriate placement 2
• High incidence of initially high implant placement that fails to settle properly 2
• Malposition occurred in 62% of revision cases in one series 3

Unnatural appearance

• The muscle coverage creates an unnatural upper pole fullness and prevents natural ptosis 4
• Contour deformities develop over time as the muscle interacts with the implant 2, 3

The Modern Supramuscular Approach

Subfascial technique (above muscle, below fascia)

• Eliminates animation deformity completely while maintaining better implant coverage than traditional subglandular placement 5
• Provides lower capsular contracture rates than subglandular placement while avoiding muscle-related complications 5
• Offers excellent lower pole coverage and more natural breast shape with brief recovery period 5
• Best suited for patients with adequate breast tissue and fascia quality 5

Prepectoral/subcutaneous reconstruction

• Increasingly used in breast reconstruction when adequate soft tissue coverage exists 4
• Provides more natural implant ptosis and appearance without muscle interference 4
• Significant reduction of capsular contracture compared to submuscular placement 4
• Avoids all animation deformities inherent to muscle coverage 4

Critical Patient Selection Criteria

Supramuscular placement requires:

• Adequate soft tissue thickness (>1-2 cm pinch test) to prevent implant visibility and rippling 5, 2
• Sufficient breast parenchyma in augmentation cases 5, 2
• Good quality pectoralis fascia for subfascial technique 5
• No planned radiation therapy in reconstruction cases, as radiation significantly increases contracture risk regardless of plane 1

Submuscular placement remains indicated for:

• Very thin patients with minimal breast tissue where implant edges would be visible 5, 2
• Patients requiring postmastectomy radiation (though staged approach with tissue expander preferred) 1
• Inadequate soft tissue coverage where prepectoral placement would risk exposure 1

Technical Modifications to Address Muscle Problems

When submuscular placement is necessary but animation is problematic:

• Selective pectoralis major denervation can be performed, severing two of three main nerve trunks to eliminate contraction in the lower two-thirds of muscle while maintaining viable soft tissue coverage 4
• Partial thickness myotomy of the pectoralis major prevents implant displacement with arm/shoulder movements 6
• These techniques maintain muscle coverage benefits while eliminating animation deformity 4, 6

Conversion from Submuscular to Supramuscular

For patients with existing submuscular implants experiencing problems:

• Pectoralis major resuspension with conversion to subglandular plane eliminates unwanted movement in 100% of cases 3
• Technique involves explantation, muscle resuspension to chest wall, and reaugmentation in subglandular position 3
• Successfully corrects malposition (62% of cases), reduces capsular contracture (53% of cases), and eliminates symmastia (10% of cases) 3
• High patient satisfaction with low complication rates in properly selected patients 3

Key Clinical Pitfalls

• Do not place implants supramuscularly in very thin patients—this guarantees visible rippling and implant edges 2
• Avoid tissue expanders/implants in previously irradiated tissue—use autologous reconstruction instead due to dramatically increased contracture and failure rates 1
• Smoking and obesity increase complications for all reconstruction types and are relative contraindications 1
• Subglandular placement without adequate fascia coverage leads to higher capsular contracture than subfascial technique 5