A planning algorithm for primary breast augmentation integrating inframammary fold morphology and chest-to-waist ratio to minimize the risk of lower pole deformities

Introduction

Background

The inframammary fold (IMF) defines the inferior border of the breast and represents a key element in breast aesthetics. It marks the transition between the thoracic wall and the upper abdomen, anchoring the breast’s natural footprint. The position and integrity of this fold largely determine the perceived shape and proportion of the augmented breast.

Inadequate evaluation or inappropriate manipulation of the IMF can lead to several well-known postoperative complications, most notably the double-bubble deformity. This deformity occurs when the combination of a newly created or lowered IMF coexists with a persistent native IMF, resulting in two visible inframammary creases. The etiology may involve incomplete release of a “strong”, “well-defined” or “constricted” IMF, resulting in persistence of the native fold, as well as an imbalance between implant dimensions and native tissue resistance or envelope compliance (1-3). The resulting discordance compromises the lower pole contour and is a challenging aesthetic complication to correct.

Rationale and knowledge gap

Traditional preoperative planning systems have emphasized breast width, nipple position, and skin envelope characteristics. However, despite its importance, the IMF often receives limited attention in these algorithms (4-9).

The variability of the breast footprint and IMF position has previously been described by Hall-Findlay, who distinguished between “high-breasted” and “low-breasted” patients, reflecting differences in vertical breast footprint and IMF location. These variations have important implications for surgical planning, as the IMF represents a relatively fixed zone of adherence that may be stretched or lowered under the influence of implants or surgical manipulation (1).

As Phillips et al. demonstrated in their seminal classification of the IMF, the morphology and laxity of the native IMF play a central role in determining the safety and success of lowering or recreating the fold whenever necessary (10). In their prospective study of over 2,000 primary breast augmentations, they identified five IMF types ranging from absent to rigidly defined folds, each with distinct surgical implications (Table 1). F2 and, in particular, F3-type IMFs raise a red flag during surgical planning, as their structural rigidity increases the risk of lower pole complications such as double-bubble deformity, observed exclusively in patients with F3a or F3b folds.

While IMF classification determines the safety of IMF manipulation and risk of lower pole complications, aesthetic outcomes are additionally influenced by overall body proportions, particularly the chest-to-waist ratio. A balanced or shorter chest-to-waist proportion enhances the perception of athleticism and youth (Figure 1). Conversely, patients with a long thorax and short waist may appear heavy or older (Figure 2). If the IMF is further lowered, this visually shortens the waist. Integrating chest-to-waist proportion into surgical planning thus prevents disproportionate lengthening of the upper body and maintains harmonious aesthetics.

Figure 1 Preoperative photo of a patient with a balanced chest-to-waist ratio: the sternal notch to IMF level distance is 20 cm while the IMF level to umbilicus distance is 18 cm. This ratio results in a youthful, athletic, slim and attractive appearance. This image was published with the patient’s consent. IMF, inframammary fold.

Figure 2 Preoperative photo of a patient with a high chest-to-waist ratio: the sternal notch to IMF level distance is 27 cm while the IMF level to umbilicus distance is 11 cm. This ratio results in a short, heavy and older-looking body type. This image was published with the patient’s consent. IMF, inframammary fold.

Objective

The purpose of this study was to combine two complementary preoperative variables—IMF morphology (risk determinant) and chest-to-waist proportion (aesthetic determinant)—into a practical and detailed step-by-step planning algorithm for primary breast augmentation. This integrated approach aims to improve decision-making regarding IMF repositioning, implant selection, and risk stratification for lower pole complications.

Methods

Patient selection and study design

This study was designed as a retrospective analysis of 126 consecutive primary bilateral breast augmentations performed by the senior author (M.G.), evaluating outcomes following application of a structured preoperative planning algorithm. Inclusion criteria were healthy adult females with no prior breast surgery.

Preoperative assessment

Each patient underwent standardized photography with arms at rest and elevated, to assess IMF effacement and its classification (Table 1), as well as chest-to-waist ratio.

Planning algorithm

We adhered to a detailed step-by-step planning algorithm (Figure 3) which we describe in detail.

Figure 3 Planning algorithm for primary breast augmentation based on chest-to-waist ratio and IMF classification. IMF, inframammary fold; TD, teardrop.

Chest-to-waist proportion

First, the IMF level was determined by transferring the IMF horizontally with a spirit level to the midline on the patient’s chest. The chest-to-waist ratio was calculated by dividing the sternal notch–IMF level distance by the IMF level–umbilicus distance. Ratios <1.1 were considered low, 1.1–1.2 balanced, and >1.2 high. A balanced chest-to-waist ratio or a low chest-to-waist ratio was considered acceptable for IMF lowering, if required for a specific implant type and volume that match the patient’s wishes (Figure 1). A long chest or short waist indicated a relative contraindication to lowering the IMF (Figure 2) as it would elongate the chest and negatively impact the patient’s proportions. One solution to provide sufficient volume in the latter case is to offer a round implant with a narrow base as it has a lower height and a lower point of maximum projection. Alternatively, we can opt for a teardrop-shaped implant as it has a low point of maximum projection, especially the implant types with a low or moderate height. As these devices require less IMF lowering, they are preferred over wide round implants or high teardrop-shaped implants.

Hedén manoeuvre

The patient is asked to place both hands on the head, as it simulates the effect of an implant on the nipple’s vertical position (2). Raising the arms lifts the chest tissue and we can start our further planning from this projected nipple height relative to the breast footprint. Both the projected nipple height as well as the IMF height are marked on the sternum. The distance between these two marks is measured. For a specific implant with height H, we would like this distance to be at least H/2 (half of the implant height), in order to achieve a nipple that is positioned centrally on the breast. If the distance between projected nipple height and IMF level is less than H/2, we would have to lower the IMF, or change our chosen implant.

The Hedén manoeuvre was performed systematically in all patients to assess the relationship between projected nipple position and the IMF. This step allows estimation of whether the selected implant height is compatible with the existing anatomy. The chest-to-waist ratio and IMF classification were then used to guide interpretation of these findings. In patients with a favourable chest-to-waist ratio, IMF lowering could be considered if required. In contrast, in patients with an unfavourable chest-to-waist ratio or a high-risk IMF type (e.g., F3), IMF lowering was avoided and implant selection was adapted accordingly.

No IMF lowering required

If, based on the Hedén manoeuvre, no IMF lowering is required, i.e., if the distance between projected nipple height and IMF level is equal to or more than H/2 of the specific implant, we can proceed with the surgery.

IMF lowering required

If however, IMF lowering is required, i.e., if the distance between projected nipple height during the Hedén manoeuvre and the IMF level is less than H/2 of the chosen implant, we have to carefully assess the IMF.

IMF assessment

We assess the IMF with the patient standing and with arms raised (effacement test, Table 1).

F0

If the patient has an underdeveloped or absent native IMF, we can proceed with the planned IMF position based on the calculation during the Hedén manoeuvre. It is, however, our duty to create and fix the new IMF at closure with reforming sutures in order to avoid bottoming-out.

F1

If the patient has a weak or mobile fold, F1, we can again proceed with the surgery, similar to an F0 patient, including the anchoring of the lowered IMF to prevent bottoming-out. F0 and F1 patients are more prone to bottoming-out than double-bubble deformity, hence IMF fixation is critical.

F2

F2 patients require attention as we are lowering a stronger IMF. We recommend limiting the inferior reset of the IMF to a maximum of 1.5 cm. The IMF has to be fixed strongly. Additionally, it is advised to release the native IMF by scoring to reduce the tendency for a residual crease. A central dual plane pocket can help to create a strong interaction between the fixed IMF and the pectoralis major muscle exerting a caudal vector.

F3a and F3b

Both F3a and F3b are red flags as the strong fascial/dermal attachments make these patients very prone to double-bubble deformity. Therefore, it is crucial to respect the native caudal footprint. If IMF lowering is required, all ancillary precautions should be taken. Alternatively, one can rethink the planning and opt for teardrop-shaped implants with a shorter height or round implants with a narrow base, prioritising projection over volume so fullness can still be achieved without inferior reset. When an F3 is identified, it is recommended to apply reverse planning: the distance between the projected nipple height and the IMF level is doubled, and this indicates the maximum height of a safe implant choice that does not require IMF lowering.

In F3b patients, the lateral fixed border increases complexity and likelihood of persistent double-bubble deformity.

3D imaging

3D simulation (Vectra Imaging, Canfield Scientific, Parsippany, NJ, USA) was performed to decide the exact implant size.

Implanted devices

Round or anatomical silicone cohesive gel implants were used. Round implants were smooth, nanotextured or microtextured. The used implant brands were Mentor [Johnson & Johnson (J&J) MedTech, CA, USA] and Motiva (Establishment Labs Holdings Inc., Costa Rica). Motiva Ergonomix implants were considered round implants within the algorithm. Despite their morphodynamic gel properties, they are not form-stable anatomical devices and therefore follow the same decision pathway as conventional round implants.

Surgical technique

All procedures were performed via an inframammary incision, with pocket creation in the subfascial or dual plane (3). Layered IMF fixation sutures were placed to maintain fold control, with four interrupted Vicryl 0 sutures in a first layer (attaching the deep thoracic fascia to the superficial fascia at the intended IMF level), followed by three interrupted Vicryl 0 sutures (connecting the joined deep and superficial fascia from the first layer to the superficial fascia of the cranial wound edge). For F2 requiring modest lowering, a central dual plane pocket was chosen, controlled scoring was done, and IMF release less than 1.5 cm was performed. F3a and F3b were generally respected; in these patients, implant height was adjusted (narrower base, shorter height and/or higher projection) rather than repositioning the IMF. All surgeries were performed under general anaesthesia; a funnel was used to introduce the implants; and patients left the hospital on the day of surgery.

Outcome measures

The primary endpoint was the incidence of double-bubble deformity. Secondary endpoints included bottoming-out, blow-out deformity, and patient-requested revisions. Double-bubble deformity was defined as the presence of a persistent visible native IMF crease (usually cranial to the new IMF), resulting in a double-contour appearance of the lower pole. Bottoming-out was defined as inferior migration of the implant (and/or IMF) resulting in an increased distance from the nipple to the lower edge of the implant. Lower pole blow-out was defined as progressive overstretching of the inferior pole with disproportionate lower-pole lengthening compared to early postoperative measurements. Outcomes were assessed clinically by the operating surgeon at follow-up visits and documented using standardized photography. Other adverse events such as wound dehiscence, infection, haematoma and seroma were recorded. Follow-up visits were conducted at 1 week, and every 3 months thereafter. Follow-up duration was recorded for each patient, and the most recent clinical evaluation was used for outcome analysis.

Statistical analysis

Statistical analysis was primarily descriptive in nature. Continuous variables are presented as mean (range), while categorical variables are reported as absolute numbers and percentages.

No formal comparative or inferential statistical analyses were performed, as the primary aim of this study was to describe the application and outcomes of a structured surgical planning algorithm in a consecutive cohort. Data management and analysis were conducted using Microsoft Excel (version 365, Microsoft Corp., Redmond, WA, USA).

Ethical consideration

This study was conducted as a retrospective analysis of consecutive patients treated according to standard clinical practice, without any intervention beyond routine care. The study was performed in accordance with the Declaration of Helsinki and its subsequent amendments. According to the policy of the Ethics Committee of AZORG Hospital and applicable Belgian regulations governing retrospective non-interventional studies using anonymized data collected during routine clinical care, formal ethical approval was not required. All patients provided informed consent for surgery and separate consent for the use of clinical photographs. No identifiable personal data are disclosed in this manuscript.

Results

IMF type distribution

For 252 breasts in 126 patients, we found 5 F0 (2.0%) and 48 F1 (19.0%) (Table 1). F2 was the most commonly identified subtype (N=131, 52.0%). F3 (both subtypes F3a and F3b), representing the highest-risk morphology for double-bubble deformity, accounted for 27.0% (N=68) of the cohort.

Frequency and magnitude of IMF lowering

Inferior repositioning of the IMF was required in 98 out of 252 breasts (38.9%) (Table 1).

In F1, IMF lowering was performed in 21 out of 48 breasts (43.8%), with routine fixation sutures.

In F2, IMF lowering was limited to ≤1.5 cm and performed in 68 out of 131 breasts (51.9%), combined with controlled scoring, central dual plane pocket creation, and reinforced fixation.

In F3, IMF lowering was avoided in the majority of patients. Reverse planning with implant height modification was applied instead. IMF lowering in this group was performed in 9 out of 68 breasts (13.2%) and only with full ancillary precautions.

The mean magnitude of IMF lowering across all cases requiring repositioning was 0.94 cm.

Chest-to-waist distribution

Based on the predefined categories, 6.3% of patients had a low chest-to-waist ratio (<1.1), 32.5% had a balanced ratio (1.1–1.2), and 61.1% had a high ratio (>1.2).

Lower pole complications

Among 126 primary augmentations, no cases of double-bubble deformity or bottoming-out were observed. Objective assessment of lower pole behavior demonstrated a mean increase in lower pole length of 1.4 cm between the first postoperative visit at 1 week and the most recent clinical evaluation.

One case of lower pole blow-out was recorded (Table 1). The patient had an F2, which was lowered, but the nipple-to-scar distance and nipple-to-IMF distance lengthened, resulting in a long lower pole (11.5 cm at eight months postoperatively compared to 9.0 cm immediately postoperatively). The patient had a preoperative chest-to-waist ratio of 1.36 (20.0 cm : 14.7 cm), classified as high. A round implant (Mentor) with smooth surface, of 400 cc, and with high profile was used. The planned algorithm was followed, including IMF lowering of 0.5 cm, controlled scoring of the native IMF, creation of a central dual plane pocket, and reinforced IMF fixation with layered sutures. No revision surgery had been performed at the time of last follow-up.

Other complications

One major complication occurred: a unilateral infection at 2.5 months postoperatively in a patient with an F2. The patient had received a round implant (Motiva), of 425 cc, with Demi projection, placed in a dual plane pocket. The infection was managed by implant removal, followed by successful delayed reimplantation after 3 months, with an uncomplicated postoperative course thereafter.

Two minor complications were seen: superficial IMF wound dehiscences, which were managed conservatively. No hematomas or seromas were recorded. There were no cases of capsular contracture, symmastia, implant rupture, or clinically significant asymmetry, defined as the absence of patient requests for re-intervention due to asymmetry.

Three patients requested elective upsizing within the first postoperative year. These cases were not considered algorithm failures but rather reflected evolving patient preferences after initial augmentation. The initial implant selection prioritized lower pole safety based on IMF morphology and tissue constraints, and no structural complications were observed in these patients.

Surgical details

The mean implant volume was 318 cc, with sizes ranging from 180 to 575 cc. The majority of implants used had a “moderate plus” or “demi” projection (69.0%), while “moderate” or “mini” projection implants accounted for 11.1% and “high” or “full” projection implants for 19.8%. No “ultra high” or “corsé” projection implants were used. Implant projection categories varied according to manufacturer-specific classifications. Round implants were selected in 60.3% of cases, whereas anatomical (teardrop-shaped) implants were used in 39.7%. Regarding implant placement, the dual plane 1.5 technique (being an intermediate modification between dual plane 1 and 2) was most commonly employed (77.8%), followed by subfascial placement (14.3%) and dual plane 2 placement (8.0%) as described by Tebbetts (3). No implants were placed in dual plane 1 or dual plane 3 positions.

Demographic details

Patient age ranged from 18 to 52 years, with a mean of 29 years (Table 2). The average body mass index (BMI) was 21.9 (ranging between 18.7 and 23.9). Parity ranged from 0 to 5 children (average 1.4 children).

Follow-up

The follow-up ranged from a minimum of 3 months to a maximum of 15 months, with a mean follow-up of 8.6 months, a median of 9 months, and an interquartile range of 6 to 12 months, for the 126 patients included. Complication rates and lower pole stability were assessed at the latest available follow-up for each patient.

Clinical case illustration

The patient with the long chest-to-waist ratio

A healthy woman in her twenties presented requesting “higher-sitting breasts”, improved symmetry, a narrower cleavage, and a natural yet proportionate round breast shape. Preoperative assessment demonstrated a relatively high chest-to-waist ratio (21.5 cm : 16 cm), which, according to the algorithm, contraindicated further lowering of the IMF to avoid excessive shortening of the waist (Figure 4A-4C). This aligned with the patient’s aesthetic preference.

Figure 4 The patient with the long chest-to-waist ratio. (A-C) Preoperative photos. (D-F) Postoperative photos at 6 months. These images were published with the patient’s consent.

Examination revealed F1 on the left and F2 on the right, without pectus deformity or significant rib prominence. She had a favorable nipple height, good lower-pole development on the right, and reduced lower-pole fullness on the left. Given the pre-existing asymmetry, implant selection required careful adjustment.

3D simulation was performed using three scenarios: symmetrical implants, asymmetry in implant width, and asymmetry in implant projection. According to patient and surgeon, the latter option provided the best balance between volume, proportion, and lower-pole behavior, and was therefore selected.

The right breast received a Motiva Ergonomix implant, demi projection, 320 cc, 11.75 cm width. The left breast received a Motiva ergonomix, full projection, 375 cc, 11.75 cm width. Both implants were placed in a medial dual plane pocket (dual plane level 1.5) to optimize medial expansion and improve cleavage (Figure 4D-4F).

Following the algorithm, the IMF was not lowered, preserving the patient’s natural proportions and preventing further shortening of her waist. No abdominal skin was recruited, as the incision was made directly in the native IMF.

The patient with an F1

A tall mother in her thirties presented requesting a natural and proportionate enhancement from an A cup to a C cup. Her chest-to-waist ratio was well balanced, and she exhibited a compliant lower pole (Figure 5A-5C).

Figure 5 The patient with F1. (A-C) Preoperative photos. (D-F) Postoperative photos at 6 months. These images were published with the patient’s consent.

Clinical examination revealed mild asymmetry, with the right IMF positioned slightly higher than the left. IMF morphology corresponded to an F1, indicating a visible IMF that effaces completely with arm elevation, favorable for modest repositioning with a very low risk of double-bubble deformity.

Smooth round implants (Mentor, cohesive I gel, 350 cc, moderate plus profile) were selected to achieve a natural, proportionate augmentation. To correct the asymmetry, the right IMF was repositioned 5 mm lower. Nipple to IMF distance was 9 cm on the right side and 9.5 cm on the left side, while the lower ventral curve (LVC) of the implant was 9 cm and the tissue thickness was 0.5 cm. Because of this shorter nipple-to-IMF distance on the right side, the incision was placed 5 mm below the native IMF, recruiting a small amount of abdominal skin into the lower pole. A medial dual plane pocket (level 1.5) was used.

Importantly, the new IMF was securely fixed using reinforcement sutures to maintain its position and prevent postoperative bottoming-out, a crucial consideration in F1 where downward implant migration may otherwise occur (Figure 5D-5F).

Reverse planning in an F3 patient

A mother in her twenties, short in stature, presented with the desire for a natural-looking augmentation in the D–DD cup range. She emphasized that she did not want a bulging upper pole. Her aesthetic preference favored a wider breast silhouette emphasizing cleavage and side-fullness rather than perkiness.

On examination, she demonstrated a favorable natural teardrop shape, compliant lower poles, and relatively empty upper poles (Figure 6A-6C). The right nipple–areola complex already rested at the upper edge of conventional bras. A strong, well-defined IMF was present bilaterally, corresponding to an F3, and her chest-to-waist ratio was high (20 cm : 14 cm). These two factors—F3 and a long chest—are strong indicators within the algorithm that the IMF should not be lowered, as this would increase the risk of double-bubble deformity and cause further visual shortening of the waist. Because of these parameters, implant selection required a reverse-planning approach, starting from the maximal implant height that would safely fit without needing IMF manipulation.

Figure 6 Reverse planning in an F3 patient. (A-C) Preoperative photos. (D-F) Postoperative photos at 6 months. These images were published with the patient’s consent.

During the Hedén manoeuvre, the nipple–areola complex was elevated to 7.0 cm above IMF on the right and 6.5 cm above IMF on the left. The maximum safe implant width equals approximately twice this distance. Hence this placed her maximum implant width at 13 cm.

After 3D simulation comparing various profiles, the patient preferred a natural, wider base with moderate anterior projection. A Motiva Ergonomix implant, Demi projection, 425 cc implant, with base width of 13 cm, was selected.

The implant’s LVC was 9.4 cm. With a measured soft-tissue thickness of 0.7 cm, the total required lower-pole capacity was 10.1 cm. Her stretched nipple–IMF distances were 10.5 cm (right) and 10.0 cm (left).

This confirmed that the implant would fit safely within the existing lower-pole envelope without exaggerated tension and without the need for abdominal skin recruitment (Figure 6D-6F).

The planning algorithm indicates that if her nipple–areola complex had been positioned lower, the 13-cm width could not have been achieved safely. In that scenario, the more appropriate choice would have been a narrower implant with a higher (full) projection, to avoid needing to lower the IMF.

The high-projection teardrop-shaped implant to ensure volume in the F3 patient

A fit, athletic woman in her thirties, short in height and with a muscular build, presented requesting a large-volume breast augmentation. Her goal was a C/D cup, a full upper pole, and a perky appearance, but she wished to remain comfortable during high-intensity sports and maintain full functional capacity.

She had broad shoulders, very thin tissues, minimal subcutaneous fat, and a tight, non-compliant lower pole. The nipple–IMF distance measured 7.5 cm, and the lower pole was underdeveloped. A mild scoliosis contributed to asymmetries, with the right IMF positioned lower and the right nipple–areola complex pointing slightly outward and downward (Figure 7A-7C).

Figure 7 The high-projection teardrop-shaped implant to ensure volume in the F3 patient. (A-C) Preoperative photos. (D-F) Postoperative photos at 7 months. These images were published with the patient’s consent.

Despite her preference for round implants and a pronounced upper pole, the anatomical constraints required a more cautious and structured approach. With tight lower-pole tissues, underdevelopment of the lower pole, and a downward-orienting nipple on the right, placing a round implant risked excessive upper-pole prominence, implant malposition, or double-bubble changes. She was therefore counseled that a teardrop-shaped implant would more safely and naturally accommodate her anatomy while still providing fullness.

Based on her lower-pole tightness and nipple–IMF height, the maximum safe implant dimensions were calculated. A 345 cc teardrop implant (Mentor CPG323) with a base width of 11.5 cm and a high profile (projection 5.8 cm) was selected. The implant had an LVC of 8.9 cm. With a soft-tissue thickness of 0.3 cm, the total required lower-pole capacity was 9.2 cm. Because her stretched nipple–IMF distance was only 7.5 cm, an additional 1.7 cm of abdominal skin needed to be incorporated into the breast footprint. Accordingly, the incision was drawn 1.7 cm below the native IMF, recruiting the necessary tissue.

Given her athletic lifestyle and strong pectoral musculature, the implant was placed in a subfascial pocket, although a central dual plane technique could have been useful in avoiding a double-bubble deformity. The native IMF was obliterated, and a new IMF was strongly fixed at the same height (Figure 7D-7F). Fat grafting of the native IMF was not performed.

Lowering the IMF in an F2 patient

A woman in her thirties, mother of three and an active fitness enthusiast, presented with the desire to feel better about herself after completing breastfeeding for her children. During consultation, she expressed preferences such as “round”, “high profile”, and “not too obvious”, aiming for a breast augmentation that was proportionate to moderately large, full yet natural, with enhanced cleavage and side fullness without an artificial or overdone appearance.

Clinical examination revealed deflated upper poles, stretchy and compliant skin, and mild asymmetries in both nipple position and breast volume. Her thorax was broad and round, with prominent axillary tail fullness, making width and horizontal volume important determinants in implant selection (Figure 8A-8C).

Figure 8 Lowering the IMF in an F2 patient. (A-C) Preoperative photos. (D-F) Postoperative photos at 3 months. These images were published with the patient’s consent. IMF, inframammary fold.

She exhibited an F2—present but partially persistent during arm elevation—indicating caution when lowering the fold due to a moderate risk of double-bubble deformity. The lower pole was compliant, stretching to 9.5 cm on the right and 10.5 cm on the left, providing sufficient capacity for controlled expansion.

Based on her breast footprint width and aesthetic goals, a smooth, round, mentor moderate plus implant (545 cc, width 14 cm) was selected. The chosen implant offered horizontal fullness (“sideboob”) and a naturally supported but not rigid upper pole (Figure 8D-8F).

The implant’s LVC measured 10.0 cm. With a soft-tissue thickness of 0.5 cm, the total lower-pole requirement was 10.5 cm. As the right lower pole stretched only to 9.5 cm, 1 cm of abdominal skin was recruited by placing the incision 1 cm below the native IMF on the right side.

During the Hedén manoeuvre, both nipples rose to 5.5 cm above the IMF, establishing that the implant width required the IMF to be lowered by 1.5 cm to achieve a central nipple-areola complex position.

Because the patient had an F2, the algorithm mandated a set of precautionary measures:

• scoring and obliteration of the native IMF;
• creation of a central dual plane pocket to allow the muscle to support the implant against the lower pole;
• secure fixation of the new IMF at its adjusted position to avoid postoperative fold migration or bottoming-out, and to provide a stable platform on which the implant can rest.

The final result delivered exactly what the patient envisioned:

• Full but natural upper pole;
• “Braless” cleavage;
• Enhanced lateral extension of the breast appropriate for her broad thoracic build;
• Central, correctly angled nipples;
• A harmonious 45:55 upper-to-lower pole volume distribution;
• No double-bubble deformity despite lowering the IMF with 1.5 cm.

Discussion

The IMF represents a key structural and aesthetic boundary of the breast. Its importance in breast augmentation lies in defining the lower pole and its sharp transition to the chest wall. In addition, it maintains long-term stability, fullness, and cleavage, serving as a reliable platform for the implant. Despite this, the IMF has historically been underestimated in preoperative planning protocols.

Relevance of IMF classification

Phillips et al. revolutionized understanding of the IMF by systematically classifying its morphology in over 2,000 patients (10). Their work demonstrated that the IMF is not a uniform structure but a variable fascial condensation, with ligamentous attachments of differing strength and dermal adherence. F0 and F1, lacking significant fascial anchoring, can be repositioned freely, but are at risk for bottoming-out if not securely fixed. F2 demands cautious release and reinforcement, while F3a and F3b are rigid, posing the highest risk for double-bubble deformity if disrupted. In their series, all double-bubble deformities occurred in F3 (<1% incidence).

Our findings reinforce these observations. By incorporating IMF typing into preoperative planning, no double-bubble deformities occurred in our cohort. This supports the hypothesis that respecting strong native folds and adapting implant dimensions accordingly is safer than lowering the fold indiscriminately. Although the absence of double-bubble deformity is encouraging, this finding should be interpreted in the context of the study’s sample size and follow-up duration.

The double-bubble deformity remains a multifactorial complication. Apart from strong IMF adherence, contributing factors include over-dissection of the lower pole, a mismatch between anatomy and implant, and unrecognized asymmetries. Prevention requires careful preoperative IMF evaluation, limited fold lowering (≤1.5 cm for F2), and secure IMF fixation. In F3, selecting a narrower or shorter implant base with higher projection achieves aesthetic fullness without fold manipulation.

Integrating chest-to-waist proportions

The chest-to-waist ratio introduces an additional aesthetic dimension often overlooked in existing algorithms. The perceived elegance and proportionality of the torso depend on maintaining a balanced relationship between chest and waist. Over-lowering the IMF in patients with a long thorax visually elongates the chest and diminishes the waist, whereas maintaining the IMF preserves youthful proportions. This concept allows individualized planning beyond local breast measurements.

It is important to distinguish between variables that determine complication risk and those that guide aesthetic proportionality. In the present algorithm, IMF morphology serves as the primary determinant of safety when considering inferior repositioning of the fold. Strong, non-effacing F3 represents the highest risk for double-bubble deformity if disrupted, whereas F0 and F1 generally tolerate repositioning but require fixation to prevent bottoming-out. In contrast, the chest-to-waist ratio is not a predictor of lower pole complications, but rather an aesthetic modifier that informs proportional harmony of the torso. While IMF classification is supported by prior evidence and directly relates to complication risk, the chest-to-waist ratio represents an experience-based parameter, and no statistical correlation with surgical outcomes was performed in this study. Its role within the algorithm should therefore be interpreted as a conceptual tool to guide aesthetic decision-making rather than a validated predictor of complications. This distinction underscores that the absence of double-bubble deformity in our cohort is attributable to morphology-based surgical planning rather than proportional analysis alone.

Clinical implications

This algorithm provides a practical, reproducible tool for planning primary breast augmentation for both junior and senior plastic surgeons. It complements existing tissue-based planning systems by addressing two neglected but critical variables: IMF morphology and body proportion. The method is especially useful for challenging cases where IMF strength or torso proportions complicate standard planning. The cohort included a broad distribution of IMF types, including 27.0% high-risk F3, indicating that the algorithm was applied across a wide anatomical spectrum, with a well-represented challenging subgroup rather than predominantly favorable cases.

Several other tissue-based planning systems have been described, including those by Tebbetts, Hedén, and Mallucci (4,5,8). These approaches have demonstrated low rates of complications when applied rigorously. However, most do not explicitly incorporate IMF morphology as an independent variable, nor do they account for torso proportions such as the chest-to-waist ratio. The present algorithm integrates IMF classification as a determinant of lower pole risk and chest-to-waist ratio as an aesthetic modifier. Direct comparison of complication rates remains difficult due to heterogeneity in study design and outcome definitions, but the absence of double-bubble deformity in our cohort suggests that structured IMF-based planning may contribute to improved lower pole stability. This algorithm does not eliminate risk but aims to redistribute it through anatomy-based decision-making.

Limitations

This study’s limitations include a relatively short follow-up period for a subgroup of patients (minimum 3 months), which may underestimate late-onset complications such as delayed bottoming-out, progressive fold descent or implant malposition. Although no double-bubble deformities were observed within the available follow-up period, and double-bubble deformity typically presents early postoperatively, longer-term surveillance is required to confirm durability of IMF stability.

Outcome assessment was descriptive and performed by the operating surgeon without independent or blinded evaluation, which may theoretically introduce observer bias. Future studies should incorporate blinded evaluators.

Additionally, variables such as skin elasticity, breast parenchymal thickness, and implant texture were not statistically analyzed.

Future multicenter studies can be performed to validate this approach and quantify its impact on complication rates and aesthetic outcomes.

Conclusions

The IMF is a dynamic and variable anatomical structure that requires individualized assessment in breast augmentation. Incorporating the IMF classification and the chest-to-waist ratio into preoperative planning allows surgeons to minimize lower pole deformities, including double-bubble and bottoming-out deformity, and optimize aesthetic harmony.

This algorithm offers a structured, experience-based guide for safe IMF management and implant selection, fostering early to mid-term predictability and lower pole stability in primary breast augmentation.

Acknowledgments

This work has been presented (in part) at the Barcelona Breast Meeting, in Barcelona, Spain, on March 20th 2024; at the Spring Meeting of the Royal Belgian Society for Plastic Surgery, in Antwerp, Belgium, on April 20th 2024; at the Autumn Meeting of the Royal Belgian Society for Plastic Surgery (Breast Talks – Clash of Concepts), in Brussels, Belgium, on November 29th 2025; and at the Brazilian Breast Symposium, in Florianópolis, Brazil, on April 17th 2026.

The authors wish to thank Dr. Craig Layt and Dr. Luke Stradwick who developed the classification system for the inframammary fold (IMF) and who trained the senior author (M.G.) in aesthetic breast surgery during the advanced aesthetic fellowship at the Breast Academy, Gold Coast, Australia.

Footnote

Provenance and Peer Review: This article was commissioned by the Guest Editor (Ayush Kapila) for the series “Innovations in Breast Surgery” published in Annals of Breast Surgery. The article has undergone external peer review.

Data Sharing Statement: Available at https://abs.amegroups.com/article/view/10.21037/abs-2025-1-59/dss

Peer Review File: Available at https://abs.amegroups.com/article/view/10.21037/abs-2025-1-59/prf

Funding: None.

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://abs.amegroups.com/article/view/10.21037/abs-2025-1-59/coif). The series “Innovations in Breast Surgery” was commissioned by the editorial office without any funding or sponsorship. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was performed in accordance with the Declaration of Helsinki and its subsequent amendments. According to the policy of the Ethics Committee of AZORG Hospital and applicable Belgian regulations governing retrospective non-interventional studies using anonymized data collected during routine clinical care, formal ethical approval was not required. All patients provided informed consent for surgery and separate consent for the use of clinical photographs. No identifiable personal data are disclosed in this manuscript.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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