Introduction

Subdermal single-rod contraceptive implant has been widely accepted by users and physicians and is used by over 2.5 million women worldwide¹,². In Mexico, more than 800,000 implants have been placed.

Sometimes, implants are set without following the recommended procedure, resulting in deep implants that cannot be located by palpation or are found in incorrect places, thus requiring other location techniques for their extraction³.

Training programs in all the countries where the product is available allow physicians and other health professionals to get in touch with the product profile as well as with insertion and removal methods. Attendants to these training programs can practice the techniques under professional supervision³,⁴.

Since 2011, Family Planning Service and Radiology Departments at the Hospital General de México had collaborated with other family planning services to locate and remove difficult location implants.

The implant should only be inserted by trained personnel used to the procedure.

Important to consider the following:

Location of the device under ultrasound guidance

For its easy access, simplicity, and effectiveness, ultrasound is the method of choice to locate deep non-palpable implants⁵.

Implants can be located by ultrasound transducers commonly used in gynecology; however, better results are obtained with high resolution 7.5 MHz linear array ultrasound linear⁶-⁸.

It is important to approximately determine the insertion site. Information can be obtained from the user’s card as well as asking the patient how and in which direction, the implant was inserted. In addition, a scar at the site of insertion must be found.

A correctly inserted implant might be found in the inner side of the non-dominant arm using the epicondyle 6-8 cm directly above it as reference and below the skin (subdermal tissue), implants inserted before 2008 were located 2 cm above the currently proposed (black line) site (Fig. 1).

Figure 1 Correct insertion site. Implant location, currently recommended site (white line), prior insertion site (black line). 

The implant can be identified and located by its acoustic shadow. The ultrasound image of the implant is very distinguishable, like a small but very clear echogenic drop on a cross section, and as a linear echogenic image on a longitudinal section⁶,⁷. We make a mark in the distal and proximal ends of the Nexplanon^™ (Implanon^™) and we joint them. Its marks point outs the right site where to find the device (Figs. 2 and 3).

Figure 2 Ultrasound of the arm cross section. Drop-like image of the implant and longitudinal section, linear image of the implant with its acoustic shadow. 

Figure 3 Mark of the implant. 

Materials and methods

A descriptive, prospective, and cross-sectional study was performed from January 2011 to April 2018. Patients were generally referred to our institution when the device is not palpable or when an attempt at removal of a palpable device has not been successful. Hundred and thirty-eight patients from Family Planning Services’ Department in Hospital General de México “Dr. Eduardo Liceaga” and other institutions were included in the study. Assessed parameters were age, time of insertion, location site, and location method. Statistical analysis was expressed as average and percentage.

Results

Hundred and sixty-four patients in whom the implant was not palpable were reviewed, the average age was 28.9 years (maximum 45 and minimum 18), the time between insertion and removal averaged 3.3 years (maximum 10 years and minimum 3 months). Three implants were inserted in the right arm, the rest on the left one. Forty-seven implants were found in fatty tissue (29%), 18 in fascia (11%), 94 in muscle (57%), 2 in the armpit (1.2%), and 3 were not found (1.8%). Previous attempts for removal were done on 48 patients (24 with 1, 18 with 2, 5 with 3, and 1 with 4 attempts). All these were located by ultrasound using linear transducers from 5 to 15 MHz bandwidth and high resolution. The total of the implants was removed, through minor surgery and two located in the armpit, through surgery with regional anesthesia; in one of these cases, the implant was next to the basilica vein. The average time of minor surgery was about 10 min.

We encountered no significant complications in our cohort following device removal.

Discussion

Patients may want their device removed due to side effects or a wish to return to fertility. Correct insertion of the subdermal single-rod implant favors an easy removal. It should only be inserted by qualified physicians familiar with insertion and removal techniques.

The no palpable implant is caused by an incorrect insertion technique. Migration should not be assumed as a cause of difficult location, implant might usually locate in the original site of insertion.

Amount of non-palpable implants is not possible to determine due to a lack of records, but approximately 3% are considered non-palpable⁸.

Ultrasound has proven to be the study of choice to locate an incorrect inserted implant. In this case, the total number of implants was located, except in two patients in whom implant was probably not inserted, an analysis of serum etonogestrel levels is recommended¹,⁵,⁷,⁹,¹⁰.

It is important to insist on not trying to remove or surgically explore until the implant is exactly located.

Conclusions

Implant removal must be done when its lifespan is over, otherwise, it will continue to acting on the cervical mucus, thus affecting woman’s fertility.

Support from trained personnel must be searched to remove the implant if a deep and fibrous capsule surrounding insertion occurs, as these make removal difficult.

Attempts to remove a non-palpable Implanon™ device blindly may lead to scarring, nerve or vessel damage, and potential medicolegal action¹¹.

Since 2012, Nexplanon^® has been used with its applicator, looking to decreasing deep insertion risk. The rod also contains barium, which validates its presence through simple X-rays (Fig. 4).

Figure 4 Radiopaque implant. Image of the implant on the X-ray.