Abdominal versus Standard Placement of the Sacral Nerve Stimulator Implantable Pulse Generator - Beyond the Abstract

Sacral nerve stimulation is an effective treatment modality for refractory frequency, urgency, urge incontinence, and non-obstructive urinary retention1. While the implantable pulse generator (IPG) was initially placed in the anterior abdominal wall in the 1990s, a 2001 study demonstrated improved outcomes with buttock implantation2. This location has worked successfully in subsequent years but revision rates still approach 30% due to lead migration, loss of efficacy, and pain3. This study looked to determine patient factors prompting abdominal placement, describe this technique, and examine outcomes of both standard placement and abdominal placement in a select patient population.

Sixty patients underwent standard placement of the IPG while fifteen had abdominal placement. Nearly all of these abdominal placements were due to being wheelchair-dependent or lacking gluteal fat. No patients in the abdominal group underwent revision surgeries due to pain. While the standard and abdominal groups did vary at baseline, there was no significant difference in operative duration, infection rate, or time from implantation to revision between groups.

In terms of technique, the Interstim I device with an option for the 25cm extender has been phased out. When the battery expires, it may be necessary to revise abdominally placed IPGs to the standard location if the 45cm lead with the Interstim II device does not have adequate length to reach the abdomen, tension-free, in all patients. In the future, issues with sitting or lying on the device may be less of a problem with the use of smaller devices. However, data from studies like this may be needed to demonstrate to device companies that providing extenders in the future can be beneficial in select patients.

Written by:
Adarsh Manjunath, MD, Resident Physician, Department of Urology, Northwestern University, Chicago, Illinois, Keeter MK, and Stephanie J. Kielb, MD, Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, Illinois and Kimberly Koloms, Biostatistics Collaboration Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois 

References
  1. Bosch JL, Groen J. Sacral nerve neuromodulation in the treatment of patients with refractory motor urge incontinence: long-term results of a prospective longitudinal study. The Journal of urology. 2000;163(4):1219-1222.
  2. Scheepens WA, Weil EH, van Koeveringe GA, et al. Buttock placement of the implantable pulse generator: a new implantation technique for sacral neuromodulation--a multicenter study. European urology. 2001;40(4):434-438.
  3. Brazzelli M, Murray A, Fraser C. Efficacy and safety of sacral nerve stimulation for urinary urge incontinence: a systematic review. The Journal of urology. 2006;175(3 Pt 1):835-841.
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