Population-based ultrasound reference values for inter-rectus distance: threshold prevalence, percentiles, and the limitations of fixed cutoffs.

IF 2.7 2区医学 Q1 SURGERY

Hernia Pub Date : 2026-08-31 DOI:10.1007/s10029-026-03810-8

Annukka Marttila, Katariina Kilpivaara, Jenni Kinnunen, Susanna M Savukoski, Pasi P Ohtonen, Riikka K Arffman, Lotta Vuokila, Marika H Kangasniemi, Kaisu Luiro, Maria Rajecki, Tero Rautio, Terhi T Piltonen

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Abstract

Purpose: This population-based study aimed to characterize the distribution of inter-rectus distance (IRD) and its upper range in adult women using standardized multisite ultrasound measurements and a percentile-based interpretive framework.

Methods: Data was driven from the Finnish Women's Health Study (WENDY, 2020-2023), comprising women assigned female at birth with a mean age of 35 years (age range 33-37 years, SD 0,6). Women less than six months postpartum, exclusively breastfeeding, or with prior midline abdominal surgery or hernia repair involving a midline incision or abdominoplasty were excluded. Inter-recti distance was measured at six predefined locations along the linea alba in the supine, knee-flexed resting position using ultrasound. For the analysis, the maximal IRD of each examinee across all sites was used.

Results: A total of 1,840 women with naturally occurring anatomy were examined. At the standard site 3 cm above the umbilicus, the mean IRD was 2.37 cm (SD 1.19 cm; range 0.35-9.86 cm). Nulliparous women had a lower mean IRD (1.52 cm, SD 0.70 cm; 0.35-4.37 cm, n = 539) than parous women (2.71 cm, SD 1.18 cm; 0.46-9.86 cm, n = 1,301). The cohort's 80th percentile for IRD was 3.24 cm. Based on maximal IRD, 38.5% had IRD ≥ 3 cm and 5.4% exceeded 5 cm; the 95th percentile was 5.09 cm. Maximal IRD most often occurred at the level of the umbilicus (41.3%) or 3 cm above (44.1%) and rarely below the umbilicus. Maximal IRD correlated weakly with adiposity measures (body mass index (BMI) ρ = 0.227; waist ρ = 0.273; weight ρ = 0.199) and no correlation was observed with height. Regression analysis showed that each childbirth was associated with a 0.42 cm increase in maximal IRD, and BMI increased IRD by 0.061 cm per kg/m².

Conclusion: IRD is a continuous anatomical characteristic exhibiting considerable normal variation among adult women. A maximal IRD of up to 5 cm may be regarded as being within the upper tail of the population reference distribution. Fixed cutoff values should be proportionate to clinical symptoms, in order to prevent unnecessary interventions. Altogether, our findings provide population-based reference data for interpreting IRD measurements.

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基于人群的直肌间距离超声参考值：阈值患病率、百分位数和固定截止值的局限性。

目的：这项基于人群的研究旨在通过标准化的多位点超声测量和基于百分位数的解释框架来表征成年女性直肌间距离（IRD）的分布及其上限。方法：数据来自芬兰妇女健康研究（WENDY, 2020-2023），包括出生时被指定为女性的妇女，平均年龄为35岁（年龄范围33-37岁，SD 0,6）。排除了产后不到6个月、纯母乳喂养或既往腹部中线手术或疝修补术（包括中线切口或腹部成形术）的妇女。在仰卧位，膝关节屈曲休息时，使用超声在沿白线的六个预定位置测量直肌间距离。为了进行分析，我们使用了每个考生在所有地点的最大IRD。结果：共对1,840名女性进行了自然解剖检查。在脐部以上3cm标准处，平均IRD为2.37 cm （SD 1.19 cm，范围0.35-9.86 cm）。未产妇女的平均IRD （1.52 cm, SD 0.70 cm; 0.35-4.37 cm, n = 539）低于已产妇女（2.71 cm, SD 1.18 cm; 0.46-9.86 cm, n = 1,301）。该队列的第80百分位IRD为3.24 cm。最大内径≥3cm的占38.5%，超过5cm的占5.4%；第95百分位为5.09 cm。最大IRD最常发生在脐部（41.3%）或3cm以上（44.1%），很少发生在脐部以下。最大IRD与肥胖测量呈弱相关(体重指数(BMI) ρ = 0.227；腰围ρ = 0.273；体重ρ = 0.199)，与身高无相关性。回归分析显示，每生育一次，最大IRD增加0.42 cm， BMI使IRD增加0.061 cm / kg/m²。结论：IRD是一种连续的解剖特征，在成年女性中表现出相当大的正常变异。最大IRD达5厘米可被视为在种群参考分布的上尾。固定的临界值应与临床症状成比例，以防止不必要的干预。总之，我们的研究结果为解释税务局的测量结果提供了基于人群的参考数据。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Hernia SURGERY-

CiteScore

4.90

自引率

26.10%

发文量

171

审稿时长

4-8 weeks

期刊介绍： Hernia was founded in 1997 by Jean P. Chevrel with the purpose of promoting clinical studies and basic research as they apply to groin hernias and the abdominal wall . Since that time, a true revolution in the field of hernia studies has transformed the field from a ”simple” disease to one that is very specialized. While the majority of surgeries for primary inguinal and abdominal wall hernia are performed in hospitals worldwide, complex situations such as multi recurrences, complications, abdominal wall reconstructions and others are being studied and treated in specialist centers. As a result, major institutions and societies are creating specific parameters and criteria to better address the complexities of hernia surgery. Hernia is a journal written by surgeons who have made abdominal wall surgery their specific field of interest, but we will consider publishing content from any surgeon who wishes to improve the science of this field. The Journal aims to ensure that hernia surgery is safer and easier for surgeons as well as patients, and provides a forum to all surgeons in the exchange of new ideas, results, and important research that is the basis of professional activity.