Sternal retractors and internal mammary retractors are foundational exposure instruments in open cardiac surgery, providing the surgical team with sustained, stable access to the heart and great vessels. While both instrument types serve an exposure function, they are engineered for different phases and purposes within the same operation. This article outlines how each is designed and used in cardiac surgical practice.
What Is a Sternal Retractor?
A sternal retractor is a mechanical spreading device placed within the sternotomy incision after the sternum has been divided along the midline. Once positioned, the retractor's blades are gradually widened using a ratcheting or screw mechanism, separating the sternal edges to expose the mediastinum and heart. Sternal retractor frames are generally designed with rounded, atraumatic blade surfaces intended to distribute pressure across the bone edges and reduce the risk of sternal fracture or soft tissue injury during prolonged retraction.
What Is an Internal Mammary Retractor Used For?
An internal mammary artery (IMA) retractor is a specialized adjunct used when the surgical team needs to harvest the internal mammary artery for use as a coronary bypass graft conduit. Unlike a standard sternal retractor, an IMA retractor typically elevates and rotates one half of the divided sternum, creating an angled, elevated working plane along the chest wall that improves visualization and access to the artery running beneath the sternal edge. This design consideration is particularly relevant in coronary artery bypass grafting (CABG), where IMA grafts are commonly used because of their long-term patency characteristics.
How Are These Retractors Designed for Cardiac Use?
Both retractor types share several engineering priorities common to cardiac surgical instruments:
- Rigid frame construction to maintain consistent, stable exposure over the course of a lengthy procedure
- Smooth, atraumatic blade contact surfaces to minimize tissue and bone trauma
- Adjustable or interchangeable blade options to accommodate different patient anatomies and incision sizes
- Corrosion-resistant surgical-grade materials that withstand repeated sterilization cycles
Pediatric sternal retractor variants are also available with adjustable opening force, reflecting the different anatomical scale and tissue characteristics of younger patients.
How Do These Retractors Fit Into a Minimally Invasive Approach?
In minimally invasive cardiac surgery (MICS), traditional full sternotomy retraction is often replaced with smaller-profile, specialized retractor systems suited to limited incisions, such as mini-sternotomy or thoracotomy approaches. These systems are designed to provide adequate exposure through a smaller surgical field while still supporting safe instrument passage and visualization. INVAMED's NeoCardia line addresses this need with instruments engineered for reduced-incision cardiac access.
What Should Surgical Teams Consider During Instrument Selection?
Surgical teams typically select retractor type and blade configuration based on the planned incision (full sternotomy, mini-sternotomy, or thoracotomy), whether IMA harvesting is planned, and patient-specific anatomical factors. As with all surgical instrumentation, appropriate use depends on surgeon training, institutional protocol, and the clinical judgment of the operating team, since every surgical procedure carries inherent risks.
Frequently Asked Questions
Is an internal mammary retractor always used in cardiac surgery?
No. An IMA retractor is used specifically when the surgical plan includes harvesting the internal mammary artery as a bypass graft conduit, most commonly during CABG. Procedures that do not involve IMA harvesting typically rely on a standard sternal retractor alone.
Can sternal retractors be used in minimally invasive procedures?
Traditional sternal retractors are generally designed for full median sternotomy exposure. Minimally invasive cardiac procedures typically use smaller, purpose-built retractor systems designed for limited incisions rather than a standard full-size sternal retractor.
What materials are sternal retractors typically made from?
Sternal retractors are commonly manufactured from surgical-grade stainless steel engineered for durability, corrosion resistance, and repeated sterilization. Material and finish selection contribute to both instrument longevity and safe tissue contact.
Related INVAMED Resources
- Cardiac Surgery Instruments Products
- NeoCardia Minimally Invasive Cardiac Surgery Instruments
- Contact INVAMED for More Information
Medical Disclaimer: This article is provided for general informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendation. It is not a substitute for consultation with a qualified healthcare professional. Product indications, availability, and regulatory status vary by country. Always refer to the official Instructions for Use (IFU) and consult a licensed physician for guidance specific to your situation. INVAMED devices are intended for use by trained healthcare professionals.