Anesth Analg 2007;105:297
© 2007 International Anesthesia Research Society
doi: 10.1213/01.ane.0000263060.95757.d9
LETTER TO THE EDITOR
Relative Contraindication to Midhumeral Block in a Patient with Contraceptive Implant
Jacques Hotton, MD,
Genevieve Salvignol, MD, and
Hervé Bouaziz, MD, PhD
Department of Anesthesia; Remiremont Hospital; Remiremont (Hotton)
Department of Anesthesia; Joseph Ducuing Hospital; Toulouse (Salvignol)
Department of Anesthesia and Intensive Care; Central Hospital; Nancy, France h.bouaziz{at}chu-nancy.fr (Bouaziz)
To the Editor:
A 34-yr-old female presented for a surgical cure of trapezio-metacarpal osteoarthritis of the thumb. A midhumeral block was chosen because the patient feared general anesthesia and also desired postoperative analgesia. Once the needle insertion site had been located based on classical landmarks, the patient informed the anesthesiologist that an implant had been inserted in the medial aspect of her arm (1). The procedure was immediately stopped and the implant was easily palpated close to the planned needle insertion site. We then performed an axillary block which was uneventful as was the surgical procedure.
Implanon is the trade name for a progesterone contraceptive implant produced by Organon. It is a single rod-shaped nonbiodegradable implant that contains 68 mg of desogestrel metabolite etonogestrel which is released for at least 3 yr after which it should be replaced (2). It has a length of 4 cm and a diameter of 2 mm and is usually inserted just under the skin in the subdermis on the medial aspect of the nondominant upper arm, 6–8 cm above the elbow. Puncture of the device by the stimulating needle might possibly rupture the implant, resulting in its dysfunction (3). The rod may not be palpable after incorrect insertion, significant weight gain after insertion, or possible migration (4,5). When confronted with the clinical management of a patient with a nonpalpable Implanon, ultrasound is accurate in detecting the absence or presence of the device with a specificity and sensitivity of 95.7% and 85.7%, respectively (Fig. 1) (6). Anesthesiologists should be alert that the implant may be present and if necessary modify their treatment plan to stay away from the device.
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Figure 1. Transverse scan of Implanon implant. Implant lies immediately adjacent to the brachial artery (A), brachial vein (V), and median nerve (N). Arrowheads mark implant. Reproduced with permission from James P and Trenery J, Aust NZ J Obstet Gynaecol 2006;46:225–8, Royal Australian and New Zealand College of Obstetricians and Gynaecologists.
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REFERENCES
- Bouaziz H, Narchi P, Mercier FJ, et al. Comparison between conventional axillary block and a new approach at the midhumeral level. Anesth Analg 1997;84:1058–62.[Abstract]
- Croxatto HB, Urbancsek J, Massai R, et al. A multicentre efficacy and safety study of the single contraceptive implant Implanon. Hum Reprod 1999;14:976–81.[Abstract/Free Full Text]
- Pickard S, Bacon L. Persistent vaginal bleeding in a patient with a broken Implanon. J Fam Plann Reprod Health Care 2002;28:207–8.[Web of Science][Medline]
- Bensouda-Grimaldi L, Jonville-Bera AP, Beau-Salinas F, et al. Insertion problems, removal problems, and contraception failures with Implanon. Gynecol Obstet Fertil 2005;33:986–90.[Medline]
- Ismail H, Mansour D, Singh M. Migration of Implanon. J Fam Plann Reprod Health Care 2006;32:157–9.[Web of Science][Medline]
- Piessens SG, Palmer DC, Sampson AJ. Ultrasound localization of non-palpable Implanon. Aust NZ J Obstet Gynaecol 2006;45:112–16.[Web of Science]
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