Robotic implants spur tissue regeneration inside the body.
Robots which reside inside the body to restore or enhance biological function have long been a hope for the future. Developing such robotic implants poses challenges both in signaling between the implant and the biological host, as well as in implant design. Now, a study from researchers at Boston Children’s Hospital develops a programmable, implanted medical robot which can gradually lengthen tubular organs by applying traction forces, stimulating tissue growth in stunted organs without interfering with organ function or causing apparent discomfort. The team state that the system could treat long-gap esophageal atresia, where part of the esophagus is missing, by lengthening the small intestine in short bowel syndrome. The study is published in the journal Science Robotics.
Previous studies show that the gold standard for long-gap esophageal atresia is an operation called the Foker process which uses sutures anchored on the patient’s back to gradually pull on the esophagus. To prevent the esophagus from tearing, patients must be paralyzed in a medically induced coma and placed on mechanical ventilation in the intensive care unit for 1-4 weeks. The long period of immobilization can cause medical complications such as bone fractures and blood clots. The current study demonstrates that miniature robots can induce organ growth inside a living thing for repair or replacement, whilst avoiding the sedation and paralysis currently required for the most difficult cases of esophageal atresia.
The current study tested the device in the esophagi of pigs, where five received the implant and three served as controls. The distance between the two rings was increased by small, 2.5mm increments each day for 8 to 9 days, pulling the esophagus in opposite directions. Results show that on day 10, the segment of esophagus had increased in length by 77% on average. Data findings show a proliferation of the cells that make up the esophagus with the organ maintaining its normal diameter.
The group state that the motorized robotic device is attached only to the esophagus, allowing the pigs to move freel, and that the animals were able to eat normally even with the device applying traction to its esophagus, and showed no sign of discomfort. They go on to add that the device includes two attachment rings, placed around the esophagus and sewn into place with sutures, covered by a smooth, biocompatible, waterproof skin; a programmable control unit outside the body applies adjustable traction forces to the rings, slowly and steadily pulling the tissue in the desired direction.
The team surmise that their robotic system induced cell proliferation and lengthened part of the esophagus in a large animal by approximately 75%, while the animal remained awake and mobile. For the future, the researchers state they are now starting to test the robotic system in a large animal model of short bowel syndrome.
Source: Boston Children’s Hospital