Are Deep Contraceptive Implant Removals Predictable?

By Rebecca H. Allen, MD, MPH, Editor

Synopsis: In this retrospective cohort study of 747 patients undergoing contraceptive implant removal, lower body mass index at insertion, weight gain during use, and longer duration of use were risk factors for deep contraceptive implant removal procedures.

Source: Kendall PD, Bresnitz W, Huang J, et al. A retrospective analysis of factors associated with deep contraceptive implant removals compared to superficial removals. Contraception. 2024;137:110486.

The single rod contraceptive implant, containing 68 mg of etonogestrel (brand name Nexplanon in the United States), is placed superficially under the skin of the upper arm. The device is U.S. Food and Drug Administration (FDA) approved for up to three years of use, but there is evidence for efficacy up to four or five years.

The authors of this study sought to determine risk factors for deep contraceptive implant removal procedures. This is important because deeply placed and non-palpable implants make removals more challenging, often requiring a higher level of expertise and resources.

This was a retrospective cohort study of patients requesting contraceptive implant removal from the Division of Complex Family Planning at one academic hospital in the United States conducted from January 2014 to January 2023. This division performed all the deep and non-palpable contraceptive implant removals at the institution but also performed routine removals.

Patients were identified using procedure billing codes. Data were abstracted from the electronic medical record and included patient characteristics such as age and body mass index (BMI). If weight was available for both insertion and removal visits, the change in weight was documented.

Procedure factors included duration of implant use, prior removal attempts, and ultrasound depth of implant if ultrasound guidance was used. The deep removal cohort was defined as patients who had a non-palpable or minimally palpable implant on a physical examination that the physician determined could not be removed in the standard fashion. All deep implants were removed using ultrasound guidance with a 15 Hz linear probe with patients under local anesthesia. The remaining patients were grouped in the superficial removal cohort.

During the study period, 162 (21.7%) patients had deep implant removals, and 585 (78.3%) patients had superficial removals. The group of patients with deep removals was slightly younger (median age at time of removal, 26.0 vs. 25.0 years; P = 0.005) and more likely to identify as white (61.7% vs. 46.0%; P = 0.007).

The deep removal cohort had a lower median BMI at implant insertion compared to the superficial removal cohort (23.2 kg/m² vs. 26.6 kg/m²; P = 0.02). However, at the time of implant removal, median BMI was no different between the two groups. Nevertheless, there were more patients with a BMI > 40.0 kg/m² at the time of implant removal in the deep removal cohort (15.2% vs. 7.0%; P = 0.007).

More patients in the deep removal group also gained weight between insertion and removal (median weight gain, 6.6 kg vs. 1.8 kg; P ≤ 0.001) and had a longer duration of use (median duration of use 36.0 vs. 27.5 months; P < 0.001) compared to the superficial removal group. In addition, more implants were originally inserted as part of a reinsertion procedure in the deep removal group (37.3% vs. 17.4%; P < 0.001) compared to the superficial removal group.

A multivariable logistic regression analysis controlled for age at the time of implant removal, duration of implant use, BMI at the time of insertion, implant exchange, proportion of BMI ≥ 40.0 kg/m² at implant removal, weight change during implant use, and cannabis use. BMI at the time of implant insertion (adjusted odds ratio [aOR], 0.92; 95% confidence interval [CI], 0.87-0.98), weight change during implant use (aOR, 1.06; 95% CI, 1.02-1.10), and duration of implant use (aOR, 1.05; 95% CI, 1.02-1.07) remained associated with need for deep implant removal.

For the deep implant removals, the median depth by ultrasound was 4.0 mm (range 1.0 mm to 36.0 mm) and 97.5% were removed successfully. Four patients had to be referred to interventional radiology for removal.

Commentary

The etonogestrel contraceptive implant is sometimes (although rarely) too deeply placed, causing difficulty with removal or a non-palpable implant. There also have been reports of the implant migrating from the arm into the chest cavity through the vasculature if placed too deeply.¹ Post-marketing surveillance has estimated that deep or non-palpable implants occur in eight out of 1,000 insertions.²

Although the manufacturer requires training for providers prior to insertion and removal and has designed the implant to attempt to ensure superficial insertions, deep insertion is a risk that patients are counseled about. It is fortunate that the current iteration of the implant is radiopaque, making localization easier. The current implant can be visualized with X-ray, computed tomography scan, magnetic resonance imaging, or high-resolution sonography.

When a patient presents with a non-palpable implant, the first step is to obtain imaging of the arm, typically an X-ray of the humerus. If the implant is visualized in the correct location, then the patient can be referred to an experienced provider for removal. This may be a specially trained OB/GYN, a general surgeon, or an interventional radiologist. Providers can contact the manufacturer to be referred to a Center of Experience in deep implant removals (https://societyfp.org/clinical/implant-removal-centers-of-experience/).³

Many techniques have been described to remove deep and non-palpable implants, including continuous ultrasound guidance and fluoroscopy. If the implant is not seen in the arm, then more imaging of the chest typically is performed. If the implant still is not found, an etonogestrel level can be arranged through the manufacturer (since it is not a commercially available assay) to see if the implant is in the patient’s body.

The three risk factors for deep removals that the authors found make biological sense. A lower BMI at insertion increased the risk of deep removals. This likely is because, without adequate adipose tissue, the implant is being placed subfascially, making it difficult to palpate. Next, weight gain during implant use also will complicate removal because of the increasing thickness of the adipose tissue above the implant.

Finally, increased duration of use also may increase the scar tissue around the implant. It is important that providers do their best to place the implant as superficially as possible to avoid problems with removal later. But as this study shows, some deep insertions may be unavoidable, especially with weight gain.

Rebecca H. Allen, MD, MPH, is Professor, Department of Obstetrics and Gynecology, Warren Alpert Medical School of Brown University, Women & Infants Hospital, Providence, RI.

References

1. Simon C, Maurier A, Gaboriau L, et al. Incidence and characteristics of intravascular pulmonary migration of etonogestrel implants: A French nationwide study. Contraception. 2020;102(3):186-189.
2. Reed S, Do Minh T, Lange JA, et al. Real world data on Nexplanon procedure-related events: Final results from the Nexplanon Observational Risk Assessment study (NORA). Contraception. 2019;100(1):31-36.
3. Matulich MC, Chen MJ, Schimmoeller NR, et al. Referral center experience with nonpalpable contraceptive implant removals. Obstet Gynecol. 2019;134(4):801-806.