Diastasis recti

Introduction

Diastasis recti is a condition characterized by the separation of the rectus abdominis muscles along the midline of the abdomen. It commonly occurs in pregnant and postpartum women, but can also affect men and non-pregnant individuals due to increased intra-abdominal pressure. Understanding its anatomy, causes, and clinical implications is essential for effective management.

Anatomy and Physiology

Rectus Abdominis Muscle

The rectus abdominis is a paired muscle that runs vertically on each side of the anterior abdominal wall. It plays a crucial role in maintaining core stability, supporting posture, and assisting in movements such as flexion of the trunk.

• Muscle structure and function: Composed of segmented muscle bellies separated by tendinous intersections, allowing flexibility and strength.
• Role in core stability: Provides support to internal organs and contributes to intra-abdominal pressure regulation.

Linea Alba

The linea alba is a fibrous connective tissue that runs along the midline of the abdomen, connecting the left and right rectus muscles. Its integrity is essential for maintaining abdominal wall strength and function.

• Anatomical features: Composed of interlacing collagen fibers that provide tensile strength to the abdominal wall.
• Role in connecting rectus muscles: Maintains the alignment of rectus abdominis muscles and distributes intra-abdominal pressure evenly.

Abdominal Wall Integrity

The overall strength and stability of the abdominal wall depend on the rectus abdominis muscles, linea alba, and surrounding fascia. Disruption in this system, such as separation of the rectus muscles, can compromise function and lead to clinical symptoms.

• Function of fascia and connective tissue: Provides structural support and facilitates force transmission across the abdominal wall.
• Impact of muscle separation on abdominal stability: May result in core weakness, postural changes, and increased risk of lower back pain or hernia formation.

Etiology

Diastasis recti can result from multiple factors that increase intra-abdominal pressure or weaken the connective tissue of the linea alba. Understanding these causes helps in prevention and targeted management.

• Pregnancy-related changes: Hormonal changes, uterine enlargement, and mechanical stretching during pregnancy commonly lead to separation of the rectus abdominis muscles.
• Obesity and rapid weight gain: Excess abdominal fat increases intra-abdominal pressure, contributing to stretching and weakening of the abdominal wall.
• Genetic and connective tissue disorders: Inherited conditions affecting collagen and connective tissue integrity may predispose individuals to diastasis recti.
• Excessive abdominal strain or improper exercise: Heavy lifting, intense abdominal exercises, or incorrect posture can exacerbate muscle separation.

Pathophysiology

The pathophysiology of diastasis recti involves mechanical and structural changes to the abdominal wall. Separation of the rectus abdominis muscles alters the distribution of intra-abdominal forces and compromises core function.

• Stretching and thinning of the linea alba: Increased tension causes collagen fibers to stretch, reducing tensile strength and elasticity.
• Altered abdominal wall mechanics: The separation weakens the anterior abdominal wall, affecting posture and trunk stability.
• Potential impact on core stability and posture: Weakness of the core muscles may lead to compensatory movements, back pain, and decreased functional performance in daily activities.

Risk Factors

Several factors increase the likelihood of developing diastasis recti by affecting connective tissue integrity or placing additional strain on the abdominal wall.

• Multiparity: Multiple pregnancies increase the risk due to repeated stretching of the abdominal wall and linea alba.
• Advanced maternal age: Older maternal age is associated with decreased collagen elasticity, predisposing to muscle separation.
• High birth weight or multiple gestation: Carrying twins or delivering a large infant increases intra-abdominal pressure, contributing to separation.
• Connective tissue disorders: Conditions such as Ehlers-Danlos syndrome reduce tissue strength and increase susceptibility.

Clinical Presentation

Patients with diastasis recti often present with both aesthetic and functional concerns. Symptoms can range from a visible abdominal bulge to impaired core function.

• Visible midline bulge or abdominal protrusion: Prominent separation of the rectus muscles may be noticeable when the patient lifts the head or sits up.
• Weakness or discomfort in the abdominal wall: Patients may report difficulty performing activities requiring core strength.
• Postural changes and lower back pain: Altered abdominal mechanics can lead to compensatory spinal movements and musculoskeletal pain.
• Functional limitations: Reduced stability may affect balance, lifting, and other daily activities.

Diagnosis

Physical Examination

Diagnosis of diastasis recti is primarily clinical, based on inspection and palpation of the abdominal wall.

• Palpation and measurement of inter-recti distance: The examiner measures the gap between the rectus muscles, typically above, at, and below the umbilicus, during a partial crunch or head lift.
• Assessment of muscle strength and core function: Evaluation of abdominal muscle contraction and overall core stability helps determine functional impact.

Imaging Studies

Imaging can be used to quantify the degree of separation and assess associated structural changes.

• Ultrasound evaluation: Non-invasive method to measure inter-recti distance and assess muscle thickness.
• CT or MRI in complex cases: Provides detailed visualization of abdominal wall anatomy, useful in surgical planning or atypical presentations.

Differential Diagnosis

It is important to distinguish diastasis recti from other conditions that may present with abdominal protrusion or midline masses.

• Ventral hernia: Localized defect in the abdominal wall fascia with potential risk of bowel protrusion, unlike diastasis recti where only the linea alba is stretched.
• Abdominal wall masses: Lipomas, tumors, or cysts may mimic a bulge but are usually palpable as discrete masses.
• Obesity-related abdominal protrusion: Generalized fat deposition can resemble diastasis, but inter-recti distance remains normal.

Management

Conservative Treatment

Conservative management is the first-line approach for most patients, focusing on strengthening the abdominal wall and improving core function.

• Core strengthening and physiotherapy: Targeted exercises such as transverse abdominis activation, pelvic tilts, and gentle crunch modifications help restore muscle tone.
• Abdominal binders or support garments: Provide temporary support to reduce discomfort and assist in functional activities.
• Activity modification and ergonomic advice: Guidance on safe lifting techniques and posture can minimize further strain on the linea alba.

Surgical Treatment

Surgery may be indicated for patients with persistent separation, functional impairment, or aesthetic concerns despite conservative therapy.

• Abdominoplasty with plication: Surgical repair of the linea alba and removal of excess skin, commonly performed in postpartum women.
• Minimally invasive or laparoscopic repair: Offers reduced recovery time and smaller incisions while correcting muscle separation.
• Postoperative rehabilitation: Gradual reintroduction of core exercises and activity ensures long-term functional improvement.

Complications

Diastasis recti can lead to several functional and structural complications if left unaddressed.

• Persistent core weakness: Impaired trunk stability may affect daily activities and exercise performance.
• Back pain and postural issues: Compensation for weak abdominal muscles can strain the lumbar spine and surrounding musculature.
• Functional impairment and reduced quality of life: Limitations in physical activity and discomfort may impact overall well-being.
• Hernia formation in severe cases: Significant thinning of the linea alba may predispose to herniation of abdominal contents.

Prevention

Preventive measures aim to reduce the risk of developing diastasis recti, especially during pregnancy and postpartum periods.

• Proper exercise and core strengthening during pregnancy: Engaging in safe abdominal and pelvic floor exercises helps maintain muscle tone and supports the linea alba.
• Weight management: Maintaining healthy weight gain during pregnancy and avoiding rapid increases in abdominal pressure can reduce strain on the abdominal wall.
• Postpartum rehabilitation and gradual return to activity: Early and progressive core rehabilitation promotes recovery and minimizes persistent separation.

Prognosis

The prognosis for diastasis recti varies depending on severity, underlying risk factors, and adherence to management strategies.

• Likelihood of spontaneous resolution postpartum: Mild cases often improve within months after delivery with conservative measures.
• Factors influencing recovery: Number of pregnancies, degree of separation, connective tissue quality, and adherence to rehabilitation affect outcomes.
• Long-term functional outcomes: With appropriate management, most individuals regain core strength and abdominal stability, though some may require surgical intervention for persistent cases.

References

1. Benjamin DR, van de Water AT, Peiris CL, Taylor NF. Effects of exercise on diastasis of the rectus abdominis muscle in the antenatal and postnatal periods: a systematic review. Physiotherapy. 2014;100(1):1-8.
2. Roche A, Gilleard W, Cobbold J. Diastasis recti abdominis during the childbearing year: the significance of physical function and exercise. J Women’s Health Phys Ther. 2009;33(4):15-22.
3. Chiarello CM, Falzone A, Lissner S. Diastasis recti abdominis in women: prevalence and risk factors. Phys Ther. 2005;85(12):1139-1145.
4. Spitznagle TM, Leong FC, Van Dillen LR. Prevalence of diastasis recti abdominis in a urogynecological patient population. Int Urogynecol J. 2007;18(3): 323-328.
5. Benjamin DR, van de Water AT, Peiris CL. Management of diastasis recti abdominis in postnatal women: a clinical guideline. Aust J Physiother. 2013;59(4): 216-223.
6. Lee DG, Hodges PW. Behavior of the linea alba during abdominal exercises: implications for rehabilitation and exercise prescription. J Orthop Sports Phys Ther. 2016;46(4): 243-250.
7. Lee DG, Hodges PW. Relationship between diastasis recti abdominis and low back pain in postpartum women: a systematic review. J Women’s Health Phys Ther. 2012;36(3): 109-115.
8. Boissonnault JS, Blaschak MJ. Incidence of diastasis recti abdominis during the childbearing year. Phys Ther. 1988;68(7):1082-1086.
9. Keeler J, Haxton H, Berka C. Surgical management of severe diastasis recti abdominis: outcomes and techniques. Plast Reconstr Surg. 2016;138(5):1041-1050.
10. Coldron Y, Stokes M, Newham DJ, Cook K. The reliability of the palpation method to measure the inter-recti distance in postnatal women. Physiotherapy. 2008;94(2): 92-98.