Magnetic loop basket: a “two-in-one” instrument

• Introduction
• Patients and methods
• Preparation of the magnetic loop basket
• Endoscopic procedure
• Results
• Discussion
• References

Background and study aims: Ingested coins are the most common foreign bodies encountered in the upper gastrointestinal tract in India and if they remain in the stomach for more than 5 days they need to be removed. Ferromagnetic retrieval instruments only work if the coins are ferromagnetic; and it is difficult to maneuver a loop basket in the fundus of the stomach. A magnetic loop basket was designed in an effort to overcome these difficulties and we assessed its feasibility, safety, and effectiveness in the removal of coins from the fundus of the stomach.

Patients and methods: Twenty patients with a history of ingested coins were scheduled for removal of the coins using the magnetic loop basket. The time taken, complications, and failure rates were recorded.

Results: Twelve ferromagnetic coins were removed in a mean time of 60 seconds (range 30 - 90 seconds) and eight non-ferromagnetic coins were removed in a mean time of 150 seconds (range 90 - 180 seconds) without any failures or complications.

Conclusion: The magnetic loop basket is a safe, effective, and quick method for removing both ferromagnetic and non-ferromagnetic metallic coins.

Introduction

Ingested coins are the most common foreign bodies found in the upper gastrointestinal tract in India, and half of them are ferromagnetic [1] [2]. Most of these coins are passed spontaneously, but coins which remain in the stomach for more than 5 days need to be removed.

Various endoscopic accessories are available for the removal of coins. The use of rat-tooth forceps requires skill on the part of the endoscopist, who must align the coin in a tangential position, and this can therefore be a time-consuming method. The coins may slip at the level of sphincters, particularly at pharyngoesophageal junction. The loop basket is an effective accessory [3], but it can be difficult to maneuver in the fundus. In order to overcome these limitations we designed a novel magnetic loop basket.

Patients and methods

Twenty patients presented with coin ingestion of more than 5 days’ duration and radiographic evidence of the coin in the upper abdomen. All these patients underwent coin removal with our magnetic loop basket. The study was approved by the ethical committee of the institution and informed consent was obtained from all the patients.

Preparation of the magnetic loop basket

The magnetic loop basket is made from stainless-steel wire (0.45 mm thick, 340 cm long), a Teflon tube (9 Fr outer diameter, 150 cm long), a three-way adaptor, an 18-gauge blunt needle, a silicon valve (3 mm in diameter), a needle pipe (19 gauge, 20 cm long), an oval-shaped nylon net (maximum diameter 7 cm, minimum diameter 4.5 cm), thin nylon thread, a sewing needle, two small pipes (18 gauge, 0.3 cm long), epoxy adhesive, two magnets (diameter 3 mm, field strength 0.085 Tesla), and cotton thread.

The loop basket (Figure [1]) is prepared by doubling the 340-cm-long stainless-steel wire by making a “U” turn in the middle. Two small needle pipes are fixed at 0.3 cm and 9 cm, near the blunt end of the wire. The wires between the two needle pipes are separated into an oval shape (7 cm × 4.5 cm). The oval-shaped nylon net is sewn over the wires, and the free ends of the net are fixed to the needle pipes. The two free ends of the wire are fixed to the 20-cm-long needle pipe.

An 18-gauge blunt needle is fixed to the three-way adaptor. The 150-cm-long Teflon tube is fixed to this needle. The wire assembly is then pushed through the Teflon tube from the free end, by passing the long needle pipe end first and taking it out across the three-way adaptor. A silicon valve is placed in the three-way adaptor over the long needle pipe and covered with the plastic cap of the three-way adaptor. The end of the long needle pipe is blunted.

The two magnets are fixed to each other, and a 2.5-cm-long loop of cotton thread is fixed to the magnets.

Endoscopic procedure

The loop basket is introduced through the suction channel in the closed position and is brought to the tip of the gastroscope. The loop basket is pushed out and the magnet is fixed to the tip by making a loop knot. It is then closed so that the magnet comes close to the tip of the gastroscope.

The gastroscope is then introduced and just after crossing the gastroesophageal junction the loop basket is opened so that the magnet is suspended in the fundus to attract the ferromagnetic coin (Figure [2 a]). The gastroscope is then moved to the antrum, thus guiding the attached coin to the antrum. The loop basket is opened (Figure [2 b]) and the magnet with the coin attached is centered under the open loop of the basket (Figure [2 c]). The loop basket is then closed and the Teflon tube advanced simultaneously, in order to catch the magnet and coin (Figure [2 d]). The endoscope, with the trapped coin, is then withdrawn. Non-ferromagnetic coins are removed by the loop basket as described above but without the aid of the magnet.

Results

Ferromagnetic coins were found in 12 of the 20 patients. These were removed using the magnetic loop basket in a mean time of 60 seconds (range 30 - 90 seconds). Eight patients had non-ferromagnetic coins. These were removed using the same magnetic loop basket in a mean time of 150 seconds (range 90 - 180 seconds). None of the patients in either group experienced any adverse effects and no other endoscopic accessories were required for the removal of the coins. The procedure was performed in all the patients as an outpatient procedure, and none of the patients required any medication.

Discussion

The magnetic loop basket overcomes the limitations of our two previously described instruments, the loop basket [3] and the magnetic foreign-body retrieval instrument [4]. The magnet at the tip of the loop basket attracts the coin if it is ferromagnetic, and drags it to the antrum, where it is easier to maneuver the accessories. It also helps by attracting the coin to the center of the opened loop basket for an easier capture. If the coin is non-ferromagnetic, the loop basket still works, but without the assistance of the magnet. The magnetic loop basket therefore represents a “two-in-one” endoscopic accessory. In terms of further development, there is a need for a small magnet which can be applied to the tip of the loop basket and which can be taken into the loop basket’s Teflon tube so that the time taken for attaching the magnet to the loop basket can be eliminated.

Competing interests: None

References

• 1 Nijhawan S, Shimpi L, Mathur A. et al . Management of ingested foreign bodies in the upper gastrointestinal tract: report on 170 patients.  Indian J Gastroenterol. 2003;  22 46-48
  PubMedSearch in Google Scholar
• 2 Nijhawan S, Shimpi L. Management of ingested foreign bodies: a review.  Trop Gastroenterol. 2002;  23 54-56
  PubMedSearch in Google Scholar
• 3 Nijhawan S, Jain N, Mathur A. et al . Foreign body removal using a “homemade” loop basket.  Gastrointest Endosc. 2001;  53 540-541
  CrossrefPubMedSearch in Google Scholar
• 4 Nijhawan S, Joshi A, Shende A. et al . Endoscopy-assisted ferromagnetic foreign-body removal with a novel magnetic instrument.  Endoscopy. 2004;  36 1130
  Thieme ConnectPubMedSearch in Google Scholar

S. Nijhawan, M. D.

Department of Gastroenterology, SMS Medical College and Hospital ·

112 Panchsheel Enclave · Gokul Bhai Bhatt Marg · Durgapura · Jaipur 302018 · India ·

Fax: 91-141-2520163

Email: dr_nijhawan@yahoo.com

References

• 1 Nijhawan S, Shimpi L, Mathur A. et al . Management of ingested foreign bodies in the upper gastrointestinal tract: report on 170 patients.  Indian J Gastroenterol. 2003;  22 46-48
  PubMedSearch in Google Scholar
• 2 Nijhawan S, Shimpi L. Management of ingested foreign bodies: a review.  Trop Gastroenterol. 2002;  23 54-56
  PubMedSearch in Google Scholar
• 3 Nijhawan S, Jain N, Mathur A. et al . Foreign body removal using a “homemade” loop basket.  Gastrointest Endosc. 2001;  53 540-541
  CrossrefPubMedSearch in Google Scholar
• 4 Nijhawan S, Joshi A, Shende A. et al . Endoscopy-assisted ferromagnetic foreign-body removal with a novel magnetic instrument.  Endoscopy. 2004;  36 1130
  Thieme ConnectPubMedSearch in Google Scholar

S. Nijhawan, M. D.

Department of Gastroenterology, SMS Medical College and Hospital ·

112 Panchsheel Enclave · Gokul Bhai Bhatt Marg · Durgapura · Jaipur 302018 · India ·

Fax: 91-141-2520163

Email: dr_nijhawan@yahoo.com