The core of Daes’s argument is a careful dissection of what the existing literature actually measures. Studies invoked in the reattachment debate examine endpoints that sound interchangeable but are not: geometry and morphology of the abdominal wall, the presence of postoperative bulging, dynamic biomechanics, and clinical outcomes. Morphology, bulging, and function are related, but they are not equivalent, and conflating them has allowed a morphological observation to be mistaken for proof of a clinical benefit. Recognizing those distinctions, Daes contends, may be the key to resolving a controversy that has divided the hernia surgery community.

The first distinction is between bulging and widening, two phenomena that patients and even surgeons often conflate. Bulging is not a hernia recurrence, and it is not simply a widening of the abdominal wall. It is an anterior displacement of the abdominal contour without any fascial defect, a rounding or protrusion of the belly that can appear even when the repair itself is structurally intact. Because clinical perception of bulging varies widely between patients and observers, objective measurement matters, and Daes’s group developed a tool called Ellipse 9 for exactly that purpose.

Ellipse 9 works by drawing two ellipses over imaging of the abdomen. The first, called X1, represents the overall abdominal diameter. The second, X2, measures the distance between the semilunar lines, the fibrous boundaries running along the outer edges of the rectus muscles, and therefore reflects transverse remodeling of the waist. Two further parameters capture the phenomenon of interest: Y2 measures anterior projection, essentially how far the belly pushes forward, while the c/a ratio measures eccentricity, with values closer to one indicating a flatter contour and lower values indicating a rounder one. The distinction is not academic. In Daes’s own series, substantial expansion of the semilunar-line distance could coexist with a flatter abdomen, while a reduction in that distance could coexist with noticeable anterior rounding. In other words, the number that reattachment surgery most reliably changes is not the number that defines bulging.

That mismatch sits at the heart of the editorial. Connors, Belyansky, and colleagues elegantly demonstrated that closing the posterior rectus sheath changes postoperative morphology and reduces semilunar-line separation compared with leaving the layer open as a bridge. Daes calls this an important anatomical observation, but notes that bulging was never measured in that study. The researchers demonstrated a morphological effect; they did not demonstrate that the maneuver prevents bulging. Complementary evidence from Halpern and colleagues points in the same direction. Their study found that PRS closure produced a substantial additional reduction in semilunar-line separation, yet bulging still occurred in 18.5 percent of patients with closure versus 21.8 percent in a historical non-closure cohort, a difference that was not statistically significant. That comparison cannot establish equivalence between the two approaches, but it further separates morphological change from the bulging outcome patients actually experience.

The clinical data assembled across multiple independent groups tell a strikingly consistent story. Bulging first drew Daes’s attention after eTEP Rives repairs performed for small ventral defects with diastasis recti, the abnormal separation of the rectus muscles; after reconstruction of larger defects, improved contour is generally expected. In a series without PRS reattachment, most abdomens became flatter after surgery, although objective bulging occurred in 5 of 30 patients. Then came a complementary finding from Rossi, Signorini, and colleagues, who reported that despite systematic PRS reattachment, objective bulging occurred in 9 of 33 patients. Patients with bulging showed greater anterior projection and reductions in both X1- and X2-based eccentricity, producing a rounder contour even though the posterior layer had been faithfully closed. Taken together, these studies do not establish whether PRS closure reduces the incidence of bulging. They establish something simpler and more humbling: bulging can occur when the posterior sheath is left open, and bulging can occur when it is closed. Reattachment, whatever its other merits, does not prevent all bulging.

There is also the matter of cost, because closure is not free. Approximating two divided posterior sheaths during a wide eTEP dissection can be technically demanding and time-consuming, particularly when the tissues do not meet without tension. That practical burden matters if the maneuver is to be generalized beyond the small number of surgeons and centers dedicated to advanced abdominal wall reconstruction. Closure under tension may also fail, and posterior-layer dehiscence with subsequent intraparietal herniation, sometimes accompanied by bowel obstruction, is a recognized complication of retromuscular reconstruction. Daes is careful not to exaggerate that risk; a recent systematic review found no significant difference in postoperative interparietal hernias between closure and non-closure. But neither, he argues, should the risk be ignored. He adds two further cautions: reapproximating the divided posterior sheath restores continuity of the layer but does not recreate its native relationship with the linea alba, creating a new postoperative geometry rather than the original one, and routine PRS-to-PRS reapproximation was never actually a requirement of the original Rives principle described in 1977.

The reattachment maneuver even carries a prosthetic consequence that cuts against one of eTEP repair’s main goals. Halpern and colleagues demonstrated that closing the posterior sheath substantially narrows the semilunar-line separation, which permits the use of a narrower mesh in the underlay position. But broad retromuscular mesh coverage is often a deliberate reconstructive objective in these operations, because wide overlap is what protects against recurrence. When that is the goal, narrowing the space available for mesh is a trade-off rather than an inherent advantage. Meanwhile, the most comprehensive synthesis of the evidence to date, a systematic review of 1,112 eTEP repairs, found that postoperative outcomes were broadly comparable with and without PRS closure, and concluded that the available heterogeneous evidence did not justify a standardized recommendation for closure.

So if leaving the sheath open does not cause bulging, what does? Daes offers a hypothesis: adaptive and maladaptive remodeling. An eTEP Rives repair does more than close a defect and place a mesh; it creates an entirely new abdominal wall geometry. The linea alba is reconstructed, the rectus muscles change position and shape, and forces are redistributed through the reconstructed system. Most abdominal walls appear to adapt successfully to this new arrangement, though some may not, and bulging may reflect that maladaptive postoperative remodeling rather than the direct consequence of a suture that was or was not placed. Muscle changes may accompany and potentially contribute to this process. Daes’s group found postoperative rectus atrophy on paired CT measurements, and Rossi’s team independently demonstrated substantial postoperative reductions in rectus muscle density despite systematic PRS closure. Dynamic MRI studies further show that abdominal wall reconstruction alters muscle geometry and dynamic displacement, with considerable variability from one patient to the next.

There is even an early, tantalizing hint that rehabilitation might shift the odds. In the final 15 patients of Daes’s series, early electrostimulation followed by progressive core training was associated with no non-stressed bulging, compared with 16.7 percent in the preceding cohort, and eccentricity improved significantly. The result was of borderline statistical significance, and the cohort was small, sequential, and nonrandomized, so no causal claim can be made, but the signal is intriguing enough to demand properly controlled study. None of this means the posterior rectus sheath should never be reattached; if it comes together easily and safely, reapproximation is entirely reasonable, and excellent results from surgeons who routinely reload the layer deserve respect. But excellent surgical outcomes reflect the whole operation, including the surgeon, tissue handling, patient selection, preparation, and recovery, not necessarily a single maneuver. The real scientific frontier, Daes argues, lies beyond the open-versus-closed question: understanding how reconstruction changes geometry, muscle, and function, why most abdominal walls adapt while some do not, and whether rehabilitation can guide that adaptation. Restoring anatomy, it turns out, is only the first step. Understanding and perhaps steering how the reconstructed wall remakes itself is the science still ahead.

Subject of Research: Posterior rectus sheath reattachment and abdominal bulging after eTEP Rives hernia repair

Article Title: Posterior rectus sheath reattachment after eTEP rives: are we solving the right problem?

Article References: Daes, J. (2026). Posterior rectus sheath reattachment after eTEP rives: are we solving the right problem?. Journal of Abdominal Wall Surgery, 5, Article 17986. https://doi.org/10.3389/jaws.2026.17986

Image Credits: AI Generated

DOI: 10.3389/jaws.2026.17986

Keywords: eTEP repair, ventral hernia, posterior rectus sheath, abdominal bulging, abdominal wall reconstruction, Rives-Stoppa, rectus atrophy, diastasis recti, biomechanics, dynamic MRI, electrostimulation, hernia surgery

The study, led by Ling Li and Daoming Tian of the Center for Pelvic Floor Disorders at the First Affiliated Hospital of Kunming Medical University, recruited sixteen healthy Asian women between the ages of eighteen and thirty who had never been pregnant. This nulligravid population is a crucial reference point. Pelvic floor dysfunction, including prolapse and incontinence, affects a large share of women worldwide, but clinicians still lack a firm baseline for what the uninjured, youthful pelvic floor does when asked to perform. Without that baseline, it is difficult to say whether a given measurement in a patient is abnormal or simply part of natural variation.

To capture the pelvic floor in action, the team used a 3.0 Tesla MRI scanner, a field strength high enough to resolve fine soft-tissue detail in the midsagittal plane, the side-on view that slices the pelvis down the middle. Each participant was imaged three times in quick succession: once at rest, once while performing a maximal Valsalva maneuver, meaning a forced exhalation against a closed airway that raises intra-abdominal pressure, and once while performing a maximal voluntary pelvic floor contraction, the deliberate squeeze familiar to anyone who has practiced Kegel exercises. The researchers then measured a battery of anatomical landmarks in each state, from the position of the bladder neck and anorectal junction to the angle of the levator plate, the length of the urethra and vaginal walls, and the area of the levator hiatus, the opening through which the urethra, vagina, and rectum pass.

One of the study’s technical strengths lies in how those measurements were made. Rather than relying on raw scanner coordinates, which shift depending on how a patient is positioned on the table, the team applied a Pelvic Inclination Correction System, or PICS, coordinate framework. This approach corrects for pelvic tilt and establishes a reproducible reference line running from the pubis to the sacrococcygeal joint, allowing landmarks measured in different women and different states to be compared on equal footing. All measurements were performed independently by two radiologists using specialized segmentation software, and the average of their readings was used in the final analysis.

The reliability of those readings was generally strong. Intraclass correlation coefficients, which quantify how closely two observers agree, ranged from 0.858 to 0.999 across the three states, values that in most imaging studies would be considered excellent. The authors were careful, however, to note that some of the confidence intervals around those estimates were wide and dipped below 0.75, particularly during the Valsalva and contraction maneuvers. In a cohort of only sixteen participants, a single outlier can stretch those intervals considerably, a limitation the researchers acknowledge openly.

When the three states were compared statistically using repeated-measures analysis of variance, with a false discovery rate correction applied across thirty-three endpoint tests to guard against spurious findings, thirty-two of the thirty-three endpoints showed evidence of state-related differences. In other words, nearly every measurable feature of pelvic floor morphology changed significantly depending on whether the woman was resting, straining, or squeezing. The largest differences emerged between the two active maneuvers, Valsalva and voluntary contraction, which turned out to be far from mirror images of each other.

The numbers tell a striking story. During voluntary contraction compared with Valsalva, the anorectal junction moved upward by an average of 18.50 millimeters, the upper levator plate angle decreased by about 30.44 degrees, the M-line displacement, a measure of pelvic floor descent, was smaller by 12.69 millimeters, and the levator hiatus area shrank by 2.41 square centimeters. In plain terms, when these women actively squeezed their pelvic muscles, the entire pelvic floor lifted, the muscular plate behind the anus tilted into a more horizontal, supportive orientation, and the opening in the levator muscle narrowed. During straining, the opposite occurred: the hiatus widened, the organs descended, and the pelvic floor flattened under pressure.

Perhaps the most intriguing observation concerns the uterovaginal axis, the line running from the uterine fundus down through the cervix and vagina. The researchers sampled points along this axis and tracked their displacement across states, finding hints that different segments of the axis move by different amounts during contraction. This suggests that the pelvic floor does not behave as a single rigid sheet but as a segmented, coordinated system in which the upper and lower portions may respond differently to muscular effort. The authors describe this as a hypothesis-generating finding, one that will require three-dimensional imaging and concurrent functional measurements to confirm.

The clinical implications could be substantial. Dynamic MRI of the pelvic floor is already used to diagnose prolapse and obstructed defecation, but interpretation depends on reference values, and most existing norms come from older or parous women. By documenting how a healthy young pelvic floor responds to maximal effort, this study provides a physiological anchor for distinguishing normal function from early dysfunction. It also highlights a subtlety that matters in the clinic: straining and squeezing are not simply opposite ends of one spectrum but distinct neuromuscular configurations, and a patient’s ability to perform each correctly can reveal different problems. A woman who bears down when she intends to squeeze, a common error in pelvic floor rehabilitation, would show a pattern on dynamic MRI that is unmistakably different from a correct contraction.

The authors are appropriately cautious about how far these findings can be pushed. Sixteen women, all from a single ethnic group and a single hospital, cannot define the full range of human pelvic floor anatomy, and the nonparametric sensitivity analyses were not fully concordant with the primary results, a reminder that some findings may not survive in larger samples. Still, as an exploratory map of the living pelvic floor in motion, the study is a valuable first step. It shows that with careful coordinate correction, rigorous observer agreement, and modern 3.0 Tesla imaging, the invisible mechanics of pelvic support can be measured with precision, opening the door to better baselines, better diagnostics, and perhaps one day, imaging-guided pelvic floor training tailored to each woman’s own anatomy.

Subject of Research: Dynamic MRI assessment of pelvic floor morphology in young healthy nulligravid women during rest, Valsalva, and voluntary contraction

Article Title: Dynamic MRI of pelvic floor morphology in young, healthy Asian nulligravid women: an exploratory study across rest, Valsalva, and voluntary contraction

Article References: Li, L., Tian, D., Zeng, Y., Wang, X., Luo, Q., & Shen, J. (2026). Dynamic MRI of pelvic floor morphology in young, healthy Asian nulligravid women: an exploratory study across rest, Valsalva, and voluntary contraction. BMC Medical Imaging. https://doi.org/10.1186/s12880-026-02853-8

Image Credits: AI Generated

DOI: 10.1186/s12880-026-02853-8

Keywords: pelvic floor, dynamic MRI, nulligravid women, Valsalva maneuver, pelvic floor contraction, levator hiatus, pelvic organ prolapse, PICS coordinates, 3.0 Tesla MRI, pelvic floor dysfunction, levator ani, urogynecology