Introducing the PRIME DIEP Flap: The Next Evolution in Autologous Breast Reconstruction

Abstract

Background

Following its initial description in 1994, the deep inferior epigastric perforator (DIEP) flap has become the gold standard in autologous breast reconstruction. While sequential modifications have improved patient outcomes, functional donor site morbidity, abdominal bulge, and hernia remain a challenge. Techniques such as robotic surgery show promise in mitigating these issues but are limited by the need for specialized equipment and training.

Methods

The Paramedian Reflection for Innervated Muscle Enhancement (PRIME) DIEP flap is a novel technique that preserves innervated rectus muscle and minimizes fascial disruption without requiring robotic assistance for flap harvest. Patient selection is based on preoperative imaging, identifying a suitable dominant medial row perforator(s) with a short intramuscular course. A limited fascial incision over the perforator, followed by a paramedian fascial extension, medial reflection of the rectus abdominis, and submuscular pedicle dissection, allows for safe visualization while minimizing abdominal wall morbidity.

Results

Between June 2023 and February 2025, 15 patients underwent 18 PRIME DIEP flaps. All flaps survived, with one patient requiring reoperation for hematoma. There were no flap losses, readmissions, or donor site complications, such as bulge or hernia, at 30-day follow-up. About 72.2% of flaps were based on a single perforator, with an average flap weight of 631.7 g.

Conclusion

The PRIME DIEP flap represents the next evolution in autologous breast reconstruction by offering a reproducible, muscle- and nerve-sparing technique, enhancing abdominal wall function in suitable patients. This technical modification also allows for the incorporation of the fascial closure in a midline plication, which may improve vascularity of the fascia following DIEP flap harvest. Further prospective studies are underway to evaluate the impact on long-term functional outcomes and further refine patient selection criteria.

Keywords

DIEP flap - PRIME DIEP - abdominal wall morbidity - autologous breast reconstruction

Introduction

Since first described in 1994, the deep inferior epigastric perforator (DIEP) flap has become the gold standard in breast reconstruction due to its favorable donor site profile and consistent perforator anatomy.[1] [2] As a true perforator flap, it avoids harvesting the rectus abdominis muscle; however, intramuscular perforator dissection can still disrupt abdominal wall continuity, potentially leading to motor denervation through splitting of fascia and muscle. These factors contribute to postoperative complications such as abdominal bulge, hernia, and functional weakness. Numerous refinements have been aimed at reducing rectus disruption and preserving motor innervation, including selective perforator dissection and fascial-sparing techniques.[3] [4] However, many of these approaches increase technical complexity or require specialized instrumentation, limiting reproducibility.

Anatomical studies support favoring medial row perforators[5] and minimizing fascial incision length, as lateral intercostal nerve branches are more likely to be preserved with smaller, medially based exposures.[6] [7] Robotic-assisted (Robo-) DIEP harvest offers a recent advancement, enabling pedicle dissection through an intraperitoneal approach while minimizing muscle and fascial injury.[8] [9] However, these techniques require robotic equipment, trained personnel, posterior sheath violation, and abdominal insufflation factors that increase procedural complexity and limit accessibility.

To address these limitations, we propose a novel refinement: The Paramedian Reflection for Innervated Muscle Enhancement (PRIME) DIEP flap. This technique uses a paramedian fascial incision followed by medial reflection of the rectus abdominis muscle to enable a medial paramuscular pedicle dissection after a short intramuscular dissection of the perforator. By avoiding posterior sheath violation and minimizing muscle disruption, the PRIME DIEP flap enhances abdominal wall integrity while maintaining reproducibility and eliminating the need for robotic assistance.

Patients and Methods

All patients undergoing DIEP flap reconstruction at our institution received preoperative magnetic resonance angiography (MRA) or computed tomographic angiography (CTA). Suitable PRIME DIEP flap candidates had either a dominant single perforator or multiple large perforators that converged shortly before exiting the fascia. Ideal perforators originated from the medial row, were located near the medial rectus edge, and had an intramuscular course no longer than 4 cm ([Fig. 1]).

Fig. 1 Preoperative MRA identifying a medial row perforator suitable for PRIME DIEP flap based on location, size, and intramuscular course. DIEP, deep inferior epigastric artery perforator; MRA, magnetic resonance angiography; PRIME, paramedian reflection for innervated muscle enhancement.

The skin island is outlined across the lower abdomen in standard fashion. Perforator location is determined using preoperative imaging, and dissection proceeds to the anterior rectus sheath, where the perforator(s) is isolated.

A limited fascial incision is made directly over the perforator, just large enough to allow for intramuscular dissection and ligation of the superior runoff. The perforator is dissected free from surrounding muscle fibers with care to preserve adjacent motor nerves ([Fig. 2]). Once released, the fascial incision is extended inferomedially to the medial rectus edge and continued inferiorly along this medial edge toward the pubic symphysis. This allows for lateral reflection of the rectus abdominis, exposing the pedicle on its deep surface ([Fig. 3]). Using this paramedian approach, pedicle dissection is completed without extending the muscle split or risking injury to laterally originating motor nerves. The anterior sheath split can also be continued superiorly along the medial edge of the rectus to allow improved visualization of the pedicle if required, without further extension over the muscle itself. By keeping the fascial opening medially, the ultimate fascial closure can be included in a midline plication.

Fig. 2 Intraoperative view of a sizable perforator with a short intramuscular course, measured during dissection.

Fig. 3 Intraoperative view showing the paramedian (paramuscular) approach to the DIEP flap pedicle with medial rectus reflection. DIEP, deep inferior epigastric artery perforator.

The deep inferior epigastric artery and vein are traced caudally to their origin at the external iliac and divided in standard fashion ([Video 1]). A lighted retractor facilitates superficial retraction of the rectus, and a malleable retractor provides counterpressure on the posterior sheath.

Download Video

Video 1 Intraoperative video demonstrating harvest of a PRIME DIEP Flap through a limited muscle split after pedicle dissection via paramedian reflection of the rectus muscle. PRIME, paramedian reflection for innervated muscle enhancement; DIEP, deep inferior epigastric artery perforator.

Following pedicle harvest, the fascial defect near the linea alba is closed primarily. A running, barbed, absorbable suture is used to reinforce the closure with midline plication ([Fig. 4]). Closed suction drains are placed, and the skin is closed in standard layer abdominoplasty fashion.

Fig. 4 Intraoperative view of midline fascial plication and primary closure following pedicle harvest. Note the absence of fascial incisions beyond the central abdominal plication.

Results

Between June 2023 and February 2025, 18 PRIME DIEP flaps were performed at our institution on 15 patients. The average patient age was 53.2 years, and the mean body mass index (BMI) was 26.6 ([Table 1]). Most reconstructions (77.8%) were delayed, and the mean flap weight was 631.7 g ([Table 2]). The majority of flaps (72.2%) were designed based on a single perforator, with an average perforator diameter of 1.8 mm. The only immediate postoperative complication was a recipient site hematoma requiring operative evacuation ([Table 3]). No flap losses, reoperations, or readmissions were reported within 30 days. No evidence of bulge or hernia was reported at the first outpatient follow-up.

Table 1 Patient characteristics

Characteristics	Overall, N = 15[a]
Age (years)	53.2 (7.5)
Race
White	10 (66.7%)
Asian	3 (20.0%)
Unknown	2 (13.3%)
Body mass index (kg/m2)	26.6 (2.8)
Smoking status
Former smoker	4 (26.7%)
Never smoker	11 (73.3%)
ASA class
P2	3 (20%)
P3	12 (80%)
Diabetes
Yes	1 (6.7%)
No	14 (93.3%)
Hyperlipidemia
Yes	4 (26.7%)
No	11 (73.3%)
Hypertension
Yes	4 (26.7%)
No	11 (73.3%)
Chemotherapy
Neoadjuvant	7 (46.7%)
Adjuvant	1 (6.7%)
None	7 (46.7%)
Radiation
Preoperative	7 (46.7%)
None	8 (53.3%)

^a n (%); mean (standard deviation).

Table 2 Surgical data by flap

Characteristics	Overall, N = 18[a]
Laterality
Left	6 (33.3%)
Right	6 (33.3%)
Bilateral	6 (33.3%)
Timing of reconstruction
Immediate	4 (22.2%)
Delayed	14 (77.8%)
Operative time (minutes)
Unilateral reconstruction	317.6 (53.5)
Bilateral reconstruction	435.6 (49.6)
Mastectomy weight (grams)	743.6 (306.6)
Flap weight (grams)	631.7 (161.6)
Flap type
Single perforator	13 (72.2%)
Two perforators	4 (22.2%)
Four perforators	1 (5.6%)
Flap orientation
Ipsilateral	10 (55.6%)
Contralateral	8 (44.4%)
Perforator
Size (millimeters)	1.8 (0.2)
Intramuscular course (millimeters)	28.3 (10.2)
Distance from medial rectus (millimeters)	12.5 (8.2)

^a n (%); mean (standard deviation).

Table 3 Thirty-day outcomes

Characteristics	Overall, N = 15[a]
LOS (days)	1.7 (0.5)
Flap loss	0 (0%)
Donor site
Hematoma	0 (0%)
Wound dehiscence	0 (0%)
Infection	2 (13.3%)
Recipient site
Hematoma	1 (6.7%)
Skin necrosis	2 (13.3%)
Seroma	0 (0%)
Infection	0 (0%)
Reoperation	0 (0%)
Readmission	0 (0%)

Abbreviation: LOS; length of stay.

^a n (%); mean (standard deviation).

Aesthetic outcomes are shown in [Fig. 5].

Fig. 5 Preoperative (top row) and postoperative (bottom row) photos demonstrating aesthetic outcomes following PRIME DIEP flap reconstruction. DIEP, deep inferior epigastric artery perforator; PRIME, paramedian reflection for innervated muscle enhancement.

Discussion

The PRIME DIEP flap builds upon two decades of refinement in perforator flap surgery.[7] [8] While the original DIEP technique reduced donor site morbidity compared with musculocutaneous flaps, complications such as abdominal bulge, hernia, and functional weakness persist. These outcomes are often linked to fascial disruption, muscle splitting, and inadvertent motor nerve injury during intramuscular perforator dissection.[1] [2]

Robotic-assisted DIEP harvest was introduced to address these challenges, offering pedicle dissection via an intraperitoneal approach while preserving muscle and limiting fascial injury.[9] The robotic approach improves visualization and physician ergonomics in addition to the benefits outlined above. However, this technique requires specialized equipment, robotic training, abdominal insufflation, and posterior sheath violation—factors that increase complexity, limit widespread adoption, and come with their own inherent risks. Additionally, robotic access typically requires multiple insults to the anterior sheath to allow for port placement and instrumentation, depending on the robot being used. Despite these limitations, the Robo-DIEP flap has been touted as the ideal option for limiting abdominal wall morbidity in patients undergoing autologous breast reconstruction.

The PRIME DIEP flap builds on these concepts by offering a simplified, reproducible approach that avoids posterior sheath violation and minimizes both muscle and muscular nerve disruption. By reflecting the rectus muscle superficially and laterally from the medial border and dissecting the pedicle from its undersurface, the laterally entering motor nerves are preserved. Additionally, a midline fascial plication can be used to reinforce the closure and correct for a diastasis, something that is not accounted for in the robotic approach or in discontinuous approaches using a low lateral fascial split for final dissection of the pedicle. Using a low lateral split may put the laterally orienting nerves at risk, while possibly decreasing the perfusion of the anterior fascia.

A previous case series of 98 hemiabdomens highlighted that 13 (28%) of cases were suitable candidates for the robotic technique based on preoperative CT angiogram.[10] While lateral perforators can also be considered for the PRIME approach, as is the case in robotic flaps, the facial opening is closed separately and not included in the final midline plication. In the senior authors' (R.A.J.) experience over the study period, 7.5% of all DIEP flaps performed were via the PRIME technique. Prospective collection following up long-term outcomes is underway, and it is likely this number will increase with ongoing exposure to the technique over a larger case series.

Recently, Hendrickson and Dusseldorp described a medial paramuscular approach using a paramedian fascial incision and submuscular pedicle dissection without robotic assistance.[11] Similarly, Gowda et al proposed a midline fascial incision technique for bilateral retrorectus pedicle dissection that is ergonomic, reproducible, and muscle-sparing.[12] These strategies reflect a broader movement toward fascia- and nerve-preserving DIEP flap harvests that reduce reliance on robotic platforms. They mirror the current concept of the PRIME DIEP flap and provide wide-ranging benefits to many patients without the requirement of specialized instrumentation or staff.

Traditional donor site classification systems often fail to fully capture the degree of muscular and fascial preservation achieved with newer techniques such as the PRIME DIEP flap. Weissler et al proposed an expanded nomenclature to better characterize residual abdominal anatomy, emphasizing muscle preservation, fascial resection, and nerve transection.[13] Similarly, Lee et al introduced a DIEP-specific classification system based on intraoperative nerve and muscle preservation, underscoring the heterogeneity in flap harvests often grouped under a single DIEP label.[14] The PRIME DIEP flap approach aligns with this shift by minimizing structural disruption and offering an accessible, outcomes-focused alternative to more complex methods. Not only does the PRIME DIEP flap aim to limit muscle, nerve, and fascial disruption, but it also aims to protect the vascularity of the anterior sheath. To this effect, we find this to be the most advanced DIEP flap modification to date in limiting donor site morbidity. Prospective studies with longer-term follow-up are underway to evaluate the PRIME DIEP flap's impact on abdominal wall function and to further define optimal patient and perforator selection criteria.

Conclusion

The PRIME DIEP flap is the latest advancement in autologous breast reconstruction. Preoperative imaging is key to identifying patients that are ideal candidates. By performing a limited muscle split and dissecting the pedicle from a paramedian approach around the rectus abdominus muscle, all surgeons can reduce abdominal morbidity in their patients without the use of advanced technologies. The added benefit of including the fascial opening in the midline plication during closure, not only preserves fascial perfusion but also can improve the overall cosmetic result of the abdomen.

Conflict of Interest

The authors declare that they have no conflict of interest.

• References

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Publication History

Received: 19 June 2025

Accepted: 02 November 2025

Accepted Manuscript online:
21 November 2025

Article published online:
09 December 2025