by Specimen retrieval bags, also known as endoscopic specimen retrieval bags, are medical devices primarily used for the containment and retrieval of tissue specimens from the body during minimally invasive surgical procedures such as laparoscopy. These bags allow surgeons to extract biopsy samples or excised lesions from internal organs without damage and with minimal contamination risk.
History and Development
The development of specimen retrieval bags closely followed the rise of minimally invasive surgery in the late 1980s and early 1990s. One of the key challenges with minimally invasive procedures like laparoscopy was how to safely extract biopsy samples or excised tissues through narrow ports without compromising specimen integrity. Early techniques involved withdrawing tissues directly through trocars which often resulted in fragmentation or contamination issues.
To address this, Dr. Thomas Otto from Germany invented one of the first prototype specimen retrieval bags in 1993. It consisted of a drawstring nylon pouch fitted at one end of a plastic tube. The bag could be deployed through the trocar safely containing specimens as it was retracted. Over the next decade, manufacturers refined the design incorporating new materials like latex, polymers and gases permeable fabrics to improve functionality. Advances in laparoscopic instruments also allowed for easier deployment and containment within the abdominal cavity. Today, specimen retrieval bags are an essential part of most minimally invasive surgeries.
Key Features and Construction
Modern specimen retrieval bags commonly consist of an inert porous fabric pouch attached to one end of a thin plastic delivery cannula or catheter. The pore size of the fabric allows fluids to pass through while retaining tissue fragments. Commonly used fabrics include nylon, polyester and polypropylene.
The delivery cannula provides a conduit to deploy the empty bag into the body cavity and retract it once filled without loss of pneumoperitoneum. Strong but flexible plastic like polyethylene or polyurethane is generally used for the cannula.
At the proximal end outside the body, the cannula is fitted with a drawstring mechanism to securely close the bag opening before removal. This consists of loops, rings or clips that the surgeon can tighten from outside to seal the bag contents. Some advanced bags may have an integrated drawstring deployment system connected to the cannula handle for ease of use.
Sizing of specimen retrieval bags can vary from 5mm to 40mm depending on the nature and size of tissues expected to be extracted. Larger bags are suitable for organ biopsies while smaller 10-15mm bags work well for lymph node or appendectomy specimens. Irregular shaped bags are also available for maximum containment capability.
Contamination Control and Specimen Integrity
One of the key advantages of using specimen retrieval bags is that it prevents direct contact between excised tissues and trocar ports or the surgeon’s hands during the extraction process. This reduces the risks of potential contamination from external bacteria or accidental loss of small biopsy fragments.
The porous nature of the bag material allows bodily fluids around the specimen to drain away before removal while keeping solid tissues securely inside. This achieves a relatively “dry” specimen that retains its integrity, colour and structures instead of getting fragmented or macerated on contact with instruments during standard direct extraction techniques.
Proper deployment and closure of the drawstring once the bag is filled ensures none of the contents spill or leak out even if the bag is inadvertently dropped during transfer to pathology. This maintains specimen sterility and Wharton’s jelly throughout the post-operative examination and processing stages.
Alternative Extraction Techniques
While Specimen Retrieval Bag retrieval bags are considered the gold standard containment method today, some alternative techniques are still utilized in certain clinical situations:
– Direct withdrawal: For very small <5mm specimens, tissues can sometimes be safely removed through the trocar channel with forceps but risks fragmentation.
– Endoscopic endobags: Flexible polymer bags that can be deployed through the operating channel of flexible gastrointestinal endoscopes to extract large colon polyps or stomach tissues.
– Irrigation/suction: Flushing the cavity with saline followed by suction can be attempted for very tiny lesions but has lower yield than bag extraction.
– Entrapment snares: Specialized wire loops that can be closed over specimens in the abdomen/pelvis and extracted in toto but have limited applications.
Emerging Technologies
Ongoing innovations aim to further streamline specimen containment and processing. Some developments include:
– Self-sealing bags: Integrated closure mechanisms eliminate need for drawsstrings, simplifying use.
– Barcode/RFID tags: Identification features allow tracing specimens to correct patients inline with lab workflow automation.
– Tissue preservation solutions: Better maintenance of molecular structures for advanced diagnostic testing.
– 3D tissue mapping: Technologies to record in situ lesion location/orientation data pre-resection.
Widespread adoption of advanced specimen handling techniques is set to enhance safety, quality and diagnostic abilities of minimally invasive surgical oncology in the coming years.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
