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1. Factors predicting the effects of motor
function after bilateral subthalamic nucleus
(STN) deep brain stimulation (DBS) in
Parkinson’s disease
PRESENTER- Dr. P. ANIL KUMAR REDDY (SENIOR RESIDENT)
NEUROSURGERY

2. INTRODUCTION
• Parkinson’s disease (PD) - second most common neurodegenerative disorder.
• Long-term therapy  on-off motor fluctuations and levodopa induced dyskinesia (LID).
• Deep brain stimulation (DBS) of bilateral subthalamic nucleus (B/L STN) is done in
patients with drug refractory tremor or patients with intolerable motor complications.
• Factors related to the outcomes of STN-DBS are a major concern to clinicians who want
to predict the surgical effects in patients before the surgery.

3. AIM AND OBJECTIVES
AIM:- To find out the impact of B/L STN DBS in alleviating motor symptoms and
reducing Levodopa Equivalent daily doses (LEDD) in patients of advanced PD.
OBJECTIVES:-
1) To analyze the factors which influence the predictive value of improvement of
motor functions post B/L STN DBS..
2) To further stratify the factors influencing the levodopa responsiveness and
correlating them with post-surgical motor outcomes.
3) To evaluate the change in Quality of life(QoL) after B/L STN DBS.

4. INCLUSION AND EXCLUSION CRITERIA
INCLUSION CRITERIA:-
1) Diagnosed as idiopathic Parkinson’s disease by a movement disorder neurologist
based on the UK Parkinson’s Disease Society Brain Bank Criteria.
2) Disease duration at least ≥3 years & symptoms are effective to levodopa therapy.
3) Willing for post-op follow up of 6 months.
EXCLUSION CRITERIA:-
1) Obvious complications after surgery, such as hemorrhage, serious infection.
2) Patients with dementia or severe psychotic symptoms.

5. MATERIALS AND METHODOLOGY
• Study type- Retrospective study.
• Period of study – January 2017- June 2023 (6 month follow up)
• Population group- All patients surgically treated for B/L STN DBS for PD at our institute
fulfilling inclusion and exclusion criteria.
Parameters evaluated are :-
1) The quantum of severity of motor symptoms, assessed by Unified Parkinson's Disease
Rating Scale Part III (UPDRS III) both preop off and 6 months post op.
2) Amount of Dopaminergic dose required was calculated using LEDD (Levo-dopa
equivalent daily dose) both preop and post-operatively.
3) Levodopa responsiveness:(UPDRS III score OFF –UPDRS III score ON) / UPDRS III score
off *100%.
4) Qualitive of Life (QoL) assessed by WHO Quality of Life scale pre and post-operatively.

6. MATERIALS AND METHODOLOGY
Statistical analysis-
• The effects of bilateral STN-DBS on parkinsonian motor symptoms (UPDRS III
scores), LEDD are evaluated using Paired t-test.
• Further multivariate analysis done to estimate the independent relationship
between post-operative motor function improvement and each related factors.
• IBM SPSS version 26 software – used for further analysis.

7. DBS- SURGICAL PROCEDURE
IMAGING- STEREOTACTIC
FRAME WITH LOCALIZER
PLANNING TRAJECTORY AND TARGET OBTAINING CO-ORDINATES

8. INSERTING STEREOTACTIC FRAME
MOUNT
BURR HOLE MICRODRIVE INSERTION

9. MICRO-ELECTRODE RECORDING
MICRO-ELECTRODE CONNECTION
INSERTION OF MICRO-
ELECTRODES

10. TEST STIMULATION LEAD MEASUREMENT AND
FIXATION
SELECTED FINAL LEAD
POSITION
FIXATION OF BATTERY

11. RESULTS
• There were a total of 36 patients in which B/L STN DBS done for PD.
• Most patients belonged to the age group 51-60 years (n=13) followed by 41-50 years (n=9) .
• There were 24 (64%) males and 12 (36 %) females.
• Dyskinesia were present in 14 patients (39%) pre-operatively.
• Average motor fluctuations duration = 5.4 ± 3.9 years.
AGE IN
YEARS
N %
31-40 6 16.67%
41-50 9 25%
51-60 13 36.11%
61-70 8 22.2%
>71 1 2.78%
TOTAL 36 100%
36%
FEMALE
64%
MALE
Gender distribution

12. Average duration of disease
= 7.35 years.
• LEDD improvement:-
Pre – operative, mean LEDD - 614.41 ± 212.69
mg
Post op mean LEDD- 316.82 ± 133.01 mg 6
months post – operatively.
The reduction in the dose was highly significant
(p = 0.001).
0
2
4
6
8
10
12
14
16
18
<5 years 6-10 years >10 years
Disease duration
0
100
200
300
400
500
600
700
PRE-OP POST OP
LEDD improvement (reduction)

13. 0
10
20
30
40
50
60
70
80
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
UPDRS OFF UPDRS ON UPDRS POST OP OFF
Quality of life (QoL) improvement:-
Subjectively measured using WHO Global Quality of
Life Scale, (ranging from 0-100), highest is better QoL
DBS significantly improved the QOL ,
Pre – operatively the mean QOL - 34 ± 3
Post op mean QOL- 67 ± 3.
The improvement in the QOL was highly significant (p
= 0.02).
Severity of motor symptoms
assessed using UPDRS III showed
significant reduction in score from
46.14±1.75 in preop patients (off
phase) to 14±1.25 post DBS surgery
(off phase), (P = 0.001)
0
10
20
30
40
50
60
70
80
90
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
PREOP POST OP

14. Summarizing the motor effects
SUBSCALE RANGE Preop Baseline
6 months post op
Change in % P value
(off medication/on
stimulation)
TOTAL UPDRS III 0-108 46.14±1.75 14±1.25 69% <0.001
TREMOR 0-28 8.67±7.85 1.44±2.65 83% <0.001
RIGIDITY 0-20 10.76±4.82 3.71±3.33 66% <0.001
BRADY/AKINESIA 0-32 19.5±8.95 8.98±6.48 54% <0.001
AXIAL SYMPTOMS 0-24 11.17±5.35 6.76±3.84 40% <0.001
LEDD (mg) 614.41 ± 212.69 316.82 ± 133.01 49% 0.01

17. STUDY Mean age
(years)
Mean duration
of the
disease(years)
% change in
UPDRS III
% change in
BRADY/AKIN
ESIA scores
% change in
LEDD
M.L. Lachenmayer et
al [1]
63.1 8.5 50.5%
(6 months)
64%
(6 months)
50%
(6 months)
M.L.Hacker et al [2] 66.1 7.2 49.43%
(1 year)
47.4%
(1 year)
42.12%
(1 year)
Xin Ling Su et al [3] 54.9 11.3 56%
(3 years)
51%
(3 months)
20%
(3 months)
Our Study 56.1 7.5 69% 54% 49%
1) Subthalamic and pallidal deep brain stimulation for Parkinson's disease-meta-analysis of outcomes- M Lenard Lachenmayer, Melina Mürset,Nicolas Antih, Ines Debove, Julia
Muellner,Maëlys Bompart et al.
2) Deep brain stimulation in early-stage Parkinson disease Five-year outcomes-Mallory L. Hacker, Maxim Turchan, Lauren E. Heusinkveld, BS, Amanda D. Currie, MD, Sarah H.
Millan et al.
3) Factors predicting the instant effect of motor function after subthalamic nucleus deep brain stimulation in Parkinson’s disease Xin-Ling Su1, Xiao-Guang Luo1, Hong Lv1,Jun
Wang2, Yan Ren1 and Zhi-Yi He1.

18. Gender, disease duration and levodopa
responsiveness
PREDICTORS STRATIFICATION
FACTORS
BETA P value
Levodopa
responsiveness
GENDER Female[1] 1.1 0.0294
Male 0.6 0.2901
Disease duration < 10 years 2.0 0.0021
≥ 10 years[2] -0.1 0.8874
Duration of motor
fluctuations
≤ 03 years 3.1 0.0393
> 03 years[3] 0.5 0.3061
1) Merola A, Romagnolo A, Bernardini A, Rizzi L, Artusi CA, Lanotte M, Rizzone MG, Zibetti M, Lopiano L. Earlier versus later subthalamic deep brain stimulation in
Parkinson's disease. Parkinsonism Relat Disord. 2015; 21(8):972–5
2) Mestre TA, Espay AJ, Marras C, Eckman MH, Pollak P, Lang AE. Subthalamic nucleus-deep brain stimulation for early motor complications in Parkinson’s disease-the
EARLYSTIM trial: early is not always better. Mov Disord. 2014; 29(14):1751–6
3) Deuschl G, Schupbach M, Knudsen K, Pinsker MO, Cornu P, Rau J, Agid Y, Schade-Brittinger C. Stimulation of the subthalamic nucleus at an earlier disease stage of
Parkinson's disease: concept and standards of the EARLYSTIM-study. Parkinsonism Relat Disord. 2013;19(1):56–61

19. Micro-electrode recording
• Deviation of first electrode from target is in the range 0-3 mm on the first electrode
with mean 0.58±0.302 (Accuracy rate of 94% within 2mm)
• On the second electrode it was in the range 0-5 mm 1.0278 ±0.37 (Accuracy rate of
86% within 2mm) which showed significant difference in deviation (p value
0.0018%).
• Reposition rate was around 5.55% (2 patients with 5mm difference) both was in
second electrode.

20. DISCUSSION
• STN-DBS significantly improved the motor function of PD patients in “off-
medication/on-stimulation” 6 months after surgery in our study.
• Of all the motor symptoms, tremor demonstrated the most improvement (83%) and
axial symptoms showed minimal change (40%).
• Preoperative levodopa responsiveness may be a more accurate predictor for the
outcomes of motor function after STN-DBS in female PD patients. (estrogens
protecting dopaminergic neurons degeneration)

21. DISCUSSION
• The other two variables that influenced the predictive potency of levodopa
responsiveness on postoperative motor improvement were:-
i) Shorter disease duration (< 10 years)
ii) Shorter duration of motor fluctuations (< 3 years)
• MER helped in increasing accuracy, but second electrode had small but significant
deviation than the first , probable casue being Cerebrospinal fluid (CSF) leakage
cause brain shifting during surgery.

22. CONCLUSION
• B/L STN DBS alleviates the motor symptoms of advanced PD.
• There is significant decrease in Levodopa Equivalent Daily dose (LEDD) following
B/L STN DBS.
• B/L STN DBS subjectively improves the Quality of life significantly.
• Levodopa responsiveness, Female sex, Duration of symptoms <10 years, Duration
of motor fluctuations <3 years have greater predictive value of motor
improvement post Bilateral STN DBS in PD.

23. LIMITATIONS
• The analyses did not assess the potential effects of other comorbidities.
• Aspects like micrographia and handwriting are not assessed.
• No objective evaluation of QoL outcomes were documented.
• Cognitive and Psychomotor aspects of PD were not studied.

24. THANK YOU