Magnetic continent colostomy device.

Abstract

For patients, the principal drawback of a colostomy is the loss of faecal continence. To achieve a continent colostomy has long been the goal of surgeons. A magnetic stoma seal became feasible when a strong, light, durable magnet made of samariumcobalt became commercially available in 1972. This metal compound has the highest magnetic energy per unit volume and loses only a few per cent of its power in 100 years. A magnetic ring coated with Palacos (an acrylate used successfully for many years in orthopaedic surgery) was developed in Erlangen, Germany, and has been used there in clinical trials since 1974.The ring is implanted in the anterior abdominal wall, either at the time of abdominoperineal resection (primary) or to make an already established colostomy continent (secondary). Surgical techniqueThe stoma site is carefully chosen before operation on a flat part of the abdominal wall away from ridges and creases; often slightly higher than the usual position. The acrylic-covered magnetic ring is sterilised with gas and inserted either through the hole where the skin disc has been excised (25 to 35 mm diameter) or into the subcutaneous fat laterally from the main incision or from within the abdomen. The south pole of the magnetic ring is marked with a rim that must be sited towards the skin. The ring is then fixed in the deeper part of the subcutaneous layer by suturing the superficial fascia to the muscle fascia. The details of this technique appear to be important. After implanting and completely covering the ring, the end of the colon, protected by a rubber sheath, is drawn through the centre hole. After removing adipose tissue and trimming the end of the colon to the appropriate length, a careful primary mucocutaneous suture is performed.Conventional colostomy management is used for three to six weeks and then the magnetic cap is fitted. A special three-layer sealing washer has recently been developed, the middle layer of which is porous foam filled with activated charcoal. This permits flatus to permeate slowly without noise or odour, and patients keep the cap in position for between 8 and 18 hours daily, using a conventional enterostomy adhesive appliance the rest of the time. ResultsThere were 61 patients (55 primary and six secondary implants) of whom six died. One death may have been related to the implantation of the ring. This patient had overwhelming sepsis that might not have occurred if the ring had not been fitted. The other deaths in this short follow-up of less than a year were associated with recurrence of the original malignant disease. The indications for removing the ring from 12 patients were failure of primary mucocutaneous healing or late necrosis of the skin overlying the ring. Of the 43 patients available for review, 22 were not attempting to use the magnetic cap to effect continence. Most of these failures were the result of incomplete continence when wearing the cap-usually because the abdominal wall was too fat, the stools were too loose, the patient was too uninterested or feeble...