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New neurosurgery teams sometime miss the target in DBS resulting in 
less than expected outcomes. Over the years I have encountered 
several who had their leads implanted in the wrong place to be effective.

I had a MRI at the San Francisco Veterans Medical Center when I had 
my end-of-life stimulator replaced. My leads hadn't moved from their 
target in 8 years.


Neurosurgery. 2008 Oct;63(4):754-60; discussion 760-1. 
http://tinyurl.com/y8olcyd

Reoperation for suboptimal outcomes after deep brain stimulation surgery.

Ellis TM, Foote KD, Fernandez HH, Sudhyadhom A, Rodriguez RL, Zeilman 
P, Jacobson CE 4th, Okun MS.

Department of Neurology, Movement Disorders Center, University of 
Florida, McKnight Brain Institute, Gainesville, Florida, USA.

OBJECTIVE: To examine a case series of reoperations for deep brain 
stimulation (DBS) leads in which clinical scenarios revealed 
suboptimal outcome from a previous operation. Suboptimally placed DBS 
leads are one potential reason for unsatisfactory results after 
surgery for Parkinson's disease (PD), essential tremor (ET), or 
dystonia. In a previous study of patients who experienced suboptimal 
results, 19 of 41 patients had misplaced leads. Similarly, another 
report commented that lead placement beyond a 2- to 3-mm window 
resulted in inadequate clinical benefit, and, in 1 patient, revision 
improved outcome. The goal of the current study was to perform an 
unblinded retrospective chart review of DBS patients with 
unsatisfactory outcomes who presented for reoperation. METHODS: 
Patients who had DBS lead replacements after reoperation were 
assessed with the use of a retrospective review of an institutional 
review board-approved movement disorders database. Cases of 
reoperation for suboptimal clinical benefit were included, and cases 
of replacement of DBS leads caused by infection or hardware 
malfunction were excluded. Data points studied included age, disease 
duration, diagnosis, motor outcomes (the Unified Parkinson Disease 
Rating Scale III in PD, the Tremor Rating Scale in ET, and the 
Unified Dystonia Rating Scale in dystonia), quality of life 
(Parkinson's Disease Questionnaire-39 in PD), and the Clinician 
Global Impression scale. The data from before and after reoperation 
were examined to determine the estimated impact of repeat surgery. 
RESULTS: There were 11 patients with PD, 7 with ET, and 4 with 
dystonia. The average age of the PD group was 52 years, the disease 
duration was 10 years, and the average vector distance of the 
location of the active DBS contact was adjusted 5.5 mm. Six patients 
(54%) with PD had preoperative off medication on DBS Unified 
Parkinson Disease Rating Scale scores that could be compared with 
postoperative off medication on DBS scores. The average improvement 
across this group of patients was 24.4%. The Parkinson's Disease 
Questionnaire-39 improved in the areas of mobility (28.18), 
activities of daily living (14.77), emotion (14.72), stigma (17.61), 
and discomfort (17.42). The average age of the ET group was 66 years, 
the disease duration was 29 years, and the average adjusted distance 
was 6.1 mm. Five ET patients (83.3%) in the cohort had a 
prereplacement on DBS Tremor Rating Scale and a postreplacement on 
DBS Tremor Rating Scale with the average improvement of 60.4%. The 
average age of the dystonia group was 39 years, the average disease 
duration was 7 years, and the average adjusted lead distance was 6.7 
mm. Three patients (75%) with dystonia had prereplacement on DBS 
Unified Dystonia Rating Scale and postreplacement on DBS Unified 
Dystonia Rating Scale scores. Across these 3 dystonia patients, the 
improvement was 12.8%. Clinician Global Impression scale scores (1, 
very much improved; 2, much improved; 3, minimally improved; 4, no 
change; 5, minimally worse; 6, much worse; 7, very much worse) after 
replacement revealed the following results in patients with PD: 1, 7 
patients; 2, 3 patients; 3, 1 patient); with ET (1, 4 patients; 2, 3 
patients); and with dystonia (1, 1 patient; 2, 2 patients; 3, 1 
patient). The latency from original lead placement to reoperation 
(repositioning/revision) overall was 28.9 months (range, 2-104 mo); 
however, in leads referred from outside institutions (n = 11 
patients), this latency was 48 months (range, 12-104 mo) compared 
with leads implanted by surgeons from the University of Florida (n = 
11 patients), which was 9.7 months (range, 2-19 mo). The most common 
clinical history was failure to achieve a perceived outcome; however, 
history of an asymmetric benefit was present in 4 (18.2%) of 22 
patients, and lead migration was present in 3 (13.6%) of 22 patients. 
CONCLUSION: There are many potential causes of suboptimal benefit 
after DBS. Timely identification of suboptimal lead placements 
followed by reoperation and repositioning/replacement in a subset of 
patients may improve outcomes.

PMID: 18981887 [PubMed - indexed for MEDLINE]

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