Randomised comparative study in 217 women of three disposable plastic IUCD thread retrievers

Abstract

Objective: To assess the relative efficacy of three disposable plastic instruments in the retrieval of 'missing' IUCD threads.

Design: A prospective randomised comparative single centre study.

Setting: Family Planning Clinic in London, UK.

Subjects: 217 of 350 IUCD users referred to the research team with 'missing' IUCD threads entered the study.

Intervention: All women initially underwent exploration of the endocervical canal with Spencer Wells forceps. When this procedure did not retrieve the threads, the patients were entered into the study. A maximum of two randomly chosen plastic IUCD thread retrievers were then used in any one patient to explore the uterine cavity and capture the 'missing' threads. The order in which the two retrievers were employed was also determined at random. Four separate entries into the uterine cavity were permitted with each instrument, the endocervical canal being explored with Spencer Wells forceps after each retraction of the instrument to identify the possible descent of the threads.

Main outcome measures: Threads brought down beyond the external cervical os, or threads brought to within the endocervical canal and then grasped by Spencer Wells forceps.

Results: In approximately 40% of all patients, the threads were retrieved with Spencer Wells forceps alone and a further 40% with the disposable plastic retrievers. About 5% had no retrievable threads, and only 2.5% of the referred patients required general anaesthesia for removal of their IUCD. The analysis of the comparative trial was confined to the 197 patients with retrievable threads which could not be brought below the external os with Spencer Wells forceps. The first plastic retriever used was successful in 50% of patients. The Retrievette (59%) and the Emmett (53%) performed better than the Mi-Mark Helix (37%) in this study. The difference was statistically significant (P = 0.03) and the 95% confidence interval for the difference of the Mi-Mark Helix from the other two retrievers was 4% to 33%. This retrieval rate for the Mi-Mark Helix was much worse than in previously reported studies, though one doctor did have a better success rate with this retriever. The success rates, using a second plastic retriever randomly chosen from the two not used in the first attempt, were almost identical to those observed with the first retrievers: 63%, 56% and 36%. The success rate did not appear to be influenced by the length of thread, day of cycle, device type or parity. The success of the second retriever tried did not seem to be influenced by the retriever that had failed previously.

Conclusions: Based on our experience, the initial exploration of the endocervical canal with Spencer Wells forceps is invaluable. If this simple manoeuvre fails to retrieve the 'missing' threads, either the Retrievette or the Emmett thread retrievers are useful tools in general practice or in the family planning clinic setting.

PIP: A group of 217 women of 350 IUD users with missing IUD threads were enrolled in the investigation. The final sample of the comparative trial involved 197 patients with retrievable threads which could not be brought below the external os with Spencer Wells forceps. 143 (73%) used Gravigard; 19 (10%) the Mini-Gravigard; 21 (10%) other copper-bearing devices (Multiload, Mini-Multiload, Novagard, Ortho-Gyne-T); and 12 (6%) the Lippes Loop, while in the remaining 2 (1%) the type of device was not recorded. The endocervical canal of all women was explored with a Spencer Wells forceps, and 2 randomly chosen plastic IUD thread retrievers were used to capture the missing threads. The threads were retrieved with Spencer Wells forceps alone in about 40% of patients, and with the disposable plastic retrievers in another 40%. About 5% had not retrievable threads, and only 2-5% of the patients required general anesthesia for IUD removal. The 1st plastic retriever succeeded in removing the device in 50% of patients. The Retrievette (59%) and the Emmett (53%) performed better than the Mi-Mark Helix (37%) yielding a statistically significant difference (P=0.03). The 95% confidence interval for the difference of the Mi-Mark Helix from the other 2 retrievers was 4% to 33%. The success rates of a 2nd plastic retriever randomly chosen from 2 retrievers not used in the 1st attempt were 63%, 56%, and 36%, analogous to rates with the 1st plastic retrievers. 33 of the 47 women in whom the plastic retrievers failed, had the threads/IUDS retrieved with a metal hook, preferably with the Birnberg hook. The initial exploration of the endocervical canal with Spencer Wells forceps proved valuable, and if it fails either the Retrievette or the Emmett thread retrievers are effective in general practice or in family planning clinics.