Chopped Chin Deformity: Why Mentoplasty Might Result in a Steep Step

In surgical terms, a “chopped” appearance usually refers to a visible or palpable notch along the jawline. This occurs most frequently after a sliding genioplasty, a procedure where the surgeon cuts the chin bone (osteotomy) and slides it forward to increase projection [2].

If the bone is advanced significantly without smoothing the edges, or if the “step” created by the movement isn’t filled in, the patient is left with a literal shelf in their bone structure. This can lead to:

• The “Witch’s Chin” Ptosis: Soft tissue sagging over the bone gap.

• Visible Notching: Hollows at the sides of the chin where the bone cut ends.

• Lip Incompetence: Difficulty closing the mouth due to muscle tension over the new bone position.

The “steep step” is rarely the result of a single error but rather a combination of surgical technique and patient anatomy.

1. Significant Bone Advancement

The most common cause of a steep step is the degree of movement. When a chin is advanced more than 8–10mm, the gap between the fixed mandible and the moved segment becomes substantial. Without “shaving” or “burring” the posterior edge of the moved segment, the transition remains sharp. Research suggests that 3D-printed cutting guides are now used to minimize these intraoperative errors and ensure a smoother bone transition [1].

2. Failure to Address the Lateral “Notch”

When the central part of the chin is moved forward, the areas just behind it (the “pre-jowl” area) do not move. This creates a “step-off” or a hollow spot on either side of the chin. Expert surgeons often use hydroxyapatite or bone grafts to fill these gaps, or they perform a “widening” osteotomy to ensure the jawline remains a continuous curve rather than a jagged line [3].

3. Soft Tissue Malposition (The Mentalis Muscle)

The chin isn’t just bone; it is covered by the mentalis muscle. If this muscle is not properly reattached (suspended) during surgery, it can slide down into the “step” created by the bone movement. This creates a “drooping” or “chopped” look where the chin appears to hang unnaturally from the face. As noted in several community discussions on Reddit’s Plastic Surgery forums, patients often report “shelf-like” sensations when the muscle fails to drape correctly over the hardware.

The psychological impact of a “chopped” chin can be significant. While surgery aims to boost confidence, an unnatural result can lead to body dysmorphia or social anxiety. As we explored in our guide on The Role of Mental Health in Surgical Recovery, the emotional state of a patient plays a massive role in how they perceive their surgical outcome.

Common complications associated with mentoplasty that contribute to a “steep step” look include:

• Transient Nerve Injury: Up to 16.4% of osteotomy patients experience temporary numbness in the lower lip [4].

• Implant Displacement: In cases involving silicone implants rather than bone movement, the implant can shift upward, creating a visible “step” on the front of the chin [4].

Modern maxillofacial surgery has evolved to prevent these deformities. If you are consulting with a surgeon, ask about these techniques:

• Virtual Surgical Planning (VSP): Using 3D scans to simulate the bone movement before the first incision is made [1].
• Burring the Edge: The surgeon physically sands down the sharp edge of the “step” so the transition is gradual rather than 90 degrees.
• Extended Implants: If using an implant, “winged” or extended anatomical implants wrap around the jawline to prevent the “stuck-on” look of older, rounder implants.
• Fat Grafting: To fix a pre-existing steep step, surgeons often use autologous fat grafting to “fill in” the notches and smooth the soft tissue transition [4].

Mentoplasty is one of the 5 life-changing surgical treatments you might not know about because of its ability to completely transform the profile, but precision is the difference between a natural look and a “chopped” one.

• The Cause: A “chopped chin” or “steep step” occurs when the bone is moved forward significantly without smoothing the transition or filling the lateral gaps.
• The Risk: High-degree advancements (8mm+) are most susceptible to this deformity.
• Prevention: Demand 3D virtual planning and ask your surgeon how they plan to “smooth the transitions” at the edge of the osteotomy.
• Soft Tissue Matters: Proper reattachment of the mentalis muscle is critical to prevent a sagging, “witch-like” chin appearance.
• Fixing a “Step”: If you already have a steep step, options include revision surgery to burr the bone or non-surgical dermal fillers/fat grafting to mask the notch.

Action Plan for Prospective Patients

1. Request 3D Imaging: Ensure your surgeon uses CT-based 3D modeling to visualize the “step” before surgery.
2. Examine Profile Photos: When looking at a surgeon’s portfolio, look specifically at the 3/4 view (oblique) to see if the jawline remains smooth or shows a “notch” near the chin.
3. Discuss Hardware: Ask about the use of pre-bent low-profile plates that minimize the “feel” of hardware under the skin.

While mentoplasty is generally a safe and permanent solution for facial disharmony, avoiding the “chopped” look requires a surgeon who treats the jawline as a continuous curve, not just a single point of advancement.