Deep brain stimulation (DBS) is a common surgical procedure used for the treatment of Parkinson's disease (PD) and essential tremor. A potential complication of this procedure is hardware failure. The authors report a case of DBS hardware failure in which repeated fractures of the extension wire were caused by abnormal rotational movements of the IPG placed in the loose subclavicular tissue of an overweight female. Implantation of the IPG in the suprascapular area prevented further extension wire fractures. This strategy may be especially relevant in overweight females with loose subclavicular tissue.
Deep brain stimulation (DBS) is a common surgical procedure used for the treatment of Parkinson’s disease (PD) and essential tremor. A potential complication of this procedure is hardware failure, which could be in the form of an electrode or extension lead fracture [
Patient is a seventy-year-old right-handed female with eight-year history of PD. She was referred for DBS surgery in 2004 as she was having significant on/off effect and dyskinetic movements.
Bilateral STN-DBS surgery with two Soletra (Medtronic) units was performed in April 2004. The stimulation parameters were gradually adjusted, and medications were reduced to achieve optimal symptomatic improvement. Her dyskinesias and on/off effects were reduced significantly, and her swallowing and speech improved.
In April 2006, the patient reported that her symptoms were increasingly less well controlled and that she experienced occasional tingling-type sensations in the right retroauricular region. Interrogation of her DBS system revealed very high impedance (
Lateral X-ray showing discontinuity of the right extension lead (arrow). Note that both the right and the left connections are low relative to the skull.
In August 2006, the patient reported increased bradykinesia and speech difficulties. Her medications were increased, resulting in mild to moderate dyskinesias. Interrogation of the DBS system revealed that the impedance on the right was again
Lateral X-ray showing a new discontinuity of the right extension lead over the skull at the connection to the right DBS electrode. Note the braided appearance of the right extension lead.
Appearance of the right extension lead during the third operation.
A followup X-ray in January 2007 revealed increased density in the right extension wire at multiple places that suggested new coiling. However, on interrogation, the DBS system was found to be electrically connected and functional. Followup X-rays in February 2007 revealed further increased coiling of the right extension wire. On interrogation of the right DBS system, the impedance was found to be high for all electrode combinations. At this point, we recommended placing the right IPG in the right suprascapular position. At revision surgery in May 2007, the IPG and extension lead were found to be extensively rotated (Figure
Appearance of the right IPG and extension lead during the fourth operation. Note the extensively coiled extension lead.
The patient has been followed for 12 months after the surgery and reports continued resolution of her symptoms (Figures
Postoperative appearance of the IPG implanted in the suprascapular region after the last surgery.
Postoperative X-ray showing placement of the right IPG in suprascapular region after the last surgery.
DBS is now a well-established treatment modality for medically uncontrolled PD. As with any technology, hardware failures may occur with DBS and lead to recurrence of symptoms [
Our case is an unusual example of DBS hardware failure in which fractures of the extension wire were caused by abnormal rotational movements of the IPG placed in the loose subclavicular tissue of an overweight female. These rotations of the IPG created a continuous mechanical strain on the extension lead resulting in recurrent fractures. To prevent further recurrence, the following options were contemplated: leaving the right DBS “OFF’’ and continuing with the left DBS and medications, revision with the Kinetra IPG, revision with right IPG implantation in the abdomen, and revision with right IPG implantation in the right suprascapular position. Another option was to again place the IPG in the subclavicular region but this time more deeply and securely sutured to the subclavicular fascia; however, that would have placed the IPG too deep, given the patient’s body habitus, and would not communicate with the programmer. We recommended IPG implantation in the suprascapular position because of the patient’s concerns with the Kinetra IPG and our concern of a recurrence with implantation in the abdomen. Placement of IPGs in the abdomen has been reported [
With the recent increase in the number of DBS surgeries for PD and other neurological disorders, the number of patients presenting with DBS hardware problems will increase. Some of these hardware failures may require different strategies to prevent further episodes of recurrence. In the case of our patient, placement of the IPG in the suprascapular region provided an effective solution for preventing fracture of the extension wire caused by abnormal rotational movements of the IPG. This strategy may be especially relevant in overweight females with loose subclavicular tissue.
The authors acknowledge the skillful editorial guidance of Ms. Arlene Stolper Simon.