Clinical Case

Our patient is a 78-year-old female who initially had an InterStim sacral neuromodulation (SNM) device placed for refractory overactive bladder in 2019. In early 2022, while living out of state, her device was removed and replaced with an MRI-compatible device with effective results. Four months later she presented to our clinic with recurrent overactive bladder symptoms. Interrogation showed abnormal impedances in all leads with no patient sensation despite high stimulation.

At this time, x-rays were obtained showing severe twisting of the leads and complete migration out of the foramen (Figure 1, A and B). The patient was taken to the operating room for lead exchange and battery revision. The previous device was extracted in fragments due to the severe torsion (Figure 2). One-month follow-up confirmed the device was adequately controlling her symptoms. Unfortunately, she was seen back in the clinic 2 months later, again with worsening symptomology. X-ray images again demonstrated the device migrated out of S3. At this juncture, 2 device failures secondary to migration within 5 months warranted further investigation.

Figure 1. A and B, Fluoroscopic preoperative images showing lead migration and twisting.

Figure 2. Intraoperative photographs of extracted, fractured lead.

After thorough discussion and physical exam it was noted her battery sat just below her waistline, due to the laxity of her tissue, there was significant mobility within her subcutaneous pocket, as well as of the pocket itself, with any manipulation due to her habitus. Simple acts including removing or putting on clothing garments jostled the device in its place. Two weeks later we saw her back for surgical planning and obtained fluoroscopic evidence of our suspected cause. As seen in Figure 3, A-E, we reproduced these same conditions, and with fluoroscopic visualization actually witnessed the implantable pulse generator flipping within its pocket and confirmed our presumed diagnosis.

Figure 3. A-E, Fluoroscopic images of live video taken in clinic demonstrating battery flipping.

Twiddler’s Syndrome

Twiddler’s syndrome is a well-described phenomenon in the cardiac literature where manipulation of pacemaker and implantable cardioverter-defibrillator batteries results in twisting of the lead, ultimately causing knotting, fracture, and/or malfunction.^1,2 It is estimated to occur in 1.2% of this population with risk factors of increased BMI, female gender, and antidepressant medications.^3,4 Twiddler’s syndrome is also identified in neuromodulation devices including deep brain stimulators and intrathecal drug delivery systems.^5,6 Despite these occurrences, it remains poorly studied and understood surrounding SNM, with only 1 other described instance in the urological literature.⁷

Case Discussion

In October of 2022 the device was replaced with successful lead placement in S3. Due to documented success in the cardiac literature, during this procedure an absorbable antibacterial envelope was used to additionally anchor the device within the tissue. The device was further secured with pexy sutures in all 4 corners.⁸ Careful consideration regarding battery location ensured placement above the sacral crest to avoid future accidental manipulation.

Our patient experienced recurrent lead migration and device failure secondary to inadvertent twiddler’s syndrome. Using thorough physical exam and fluoroscopic imaging, we were able to identify an instance of unintentional manipulation consistent with twiddler’s syndrome and captured these findings with fluoroscopic video. Twiddler’s syndrome presents across all subcutaneous device implants. The standard location of SNM implants in the lower back places the devices at risk of inadvertent manipulation during daily activities such as dressing or changing position. Several pre- and intraoperative considerations for surgical planning may aid in prevention of idiopathic twiddler’s syndrome and prevent premature device failure. These include the thoughtful evaluation of a patient’s body habitus for a safe device placement location, limiting pocket size, and anchoring the device ± use of an absorbable antibacterial envelope.