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MRI-guided STN DBS in Parkinson’s disease without
microelectrode recording: efficacy and safety
T Foltynie,
1
L Zrinzo,
1,2
I Martinez-Torres,
3
E Tripoliti,
1
E Petersen,
4
E Holl,
1,5
I Aviles-Olmos,
1
M Jahanshahi,
1
M Hariz,
1,6
P Limousin
1
ABSTRACT
Deep brain stimulation (DBS) of the subthalamic nucleus
(STN) is a commonly employed therapeutic procedure for
patients with Parkinson’s disease uncontrolled by
medical therapies. This series describes the outcomes of
79 consecutive patients that underwent bilateral STN
DBS at the National Hospital for Neurology and
Neurosurgery between November 2002 and November
2008 using an MRI-guided surgical technique without
microelectrode recording. Patients underwent immediate
postoperative stereotactic MR imaging. The mean (SD)
error in electrode placement was 1.3 (0.6) mm. There
were no haemorrhagic complications. At a median
follow-up period of 12 months, there was a mean
improvement in the off-medication motor part of the
Unified Parkinson’s Disease Rating Scale (UPDRS III) of
27.7 points (SD 13.8) equivalent to a mean improvement
of 52% (p<0.0001). In addition, there were significant
improvements in dyskinesia duration, disability and pain,
with a mean reduction in on-medication dyskinesia
severity (sum of dyskinesia duration, disability and pain
from UPDRS IV) from 3.15 (SD 2.33) pre-operatively, to
1.56 (SD 1.92) post-operatively (p¼0.0001). Quality of
life improved by a mean of 5.5 points (median 7.9 points,
SD 17.3) on the Parkinson’s disease Questionnaire 39
summary index. This series confirms that image-guided
STN DBS without microelectrode recording can lead to
substantial improvements in motor disability of well-
selected PD patients with accompanying improvements
in quality of life and most importantly, with very low
morbidity.
“In clinical practice, brain imaging can now be
divided in two parts: the diagnostic neuroradiology
and the preoperative stereotactic localisation
procedure. The latter is part of the therapeutic
procedure. It is the surgeon’s responsibility and
should be closely integrated with the operation.”
Lars Leksell
1
.
Deep brain stimulation (DBS) of the subthalamic
nucleus (STN) is an accepted surgical treatment for
symptoms of Parkinson’s disease (PD) inadequately
controlled by medical therapies.
2 3
PD is a chronic
neurodegenerative disease for which many medical
treatments are available; therefore, interventions
such as STN DBS that are neither life-saving nor
disease-modifying but are aimed at improving
quality of life must meet the very highest standards
of safety. Major risks associated with the surgical
procedure include intra-cerebral haemorrhage and
infection of the implanted material, while adverse
effects of stimulation are presumably related to
stimulation of non-motor regions within or outside
of the STN.
45
Factors that may potentially
improve safety and/or efficacy of the procedure for
individual patients and for the group as a whole are
of utmost importance.
The majority of centres currently use microelec-
trode recording (MER) from individual neurons to
identify the characteristic neuronal firing patterns
or “physiological signature”of STN neurons during
surgery. Since the introduction and widespread
adoption of STN DBS for PD, there has been
a paucity of reports evaluating this procedure when
it is performed without MER.
6
This study presents
efficacy and safety outcomes of a large consecutive
prospective series of PD patients (n¼79) treated
with STN DBS in a single centre, using a stand-
ardised surgical technique based on individual
MRI-guided targeting without MER.
MATERIAL AND METHODS
Patients
Seventy-nine consecutive patients underwent STN
DBS at the National Hospital for Neurology and
Neurosurgery between November 2002 and
November 2008. All patients met UK Brain Bank
criteria for the diagnosis of PD and suffered from
disabling motor complications of the illness despite
optimal medical treatment. Before deciding on
suitability for surgery, a brain MRI was obtained to
exclude patients with advanced brain atrophy,
white matter changes or other abnormality contra-
indicating surgery. Baseline neuropsychological tests
identified patients with significant cognitive
impairment and L-dopa equivalent doses calculated
for each patient.
7
An L-dopa challenge was
performed to confirm drug responsiveness using the
motor part of the Unified Parkinson’s Disease Rating
Scale (UPDRS III). A numerical measure of L-dopa
response was derived as follows: (Off UPDRS III e
On UPDRS III score)/Off UPDRS III3100. The off-
medication state was practically defined as an
overnight period free of medication. Speech was
assessed using the Assessment of Intelligibility for
Dysarthric Speech.
8
Patients were asked to complete
the Parkinson’s Disease Questionnaire 39 scale
(PDQ39).
9
The final decision regarding the appro-
priateness of STN DBS surgery for each patient was
taken during a joint meeting of patient, immediate
family, neurologist(s) and neurosurgeon(s).
Image acquisition and surgical procedure
Surgery was usually performed under local anaes-
thesia, in the off-medication condition, to allow
clinical evaluation during electrode placement. If
the patient was unable to tolerate prolonged
periods off medication, surgery was performed
under general anaesthesia (n¼12). The STN was
See Editorial Commentary,
p 356
1
Unit of Functional
Neurosurgery, Sobell
Department of Motor
Neuroscience, UCL Institute of
Neurology, Queen Square,
London, UK
2
Victor Horsley Department of
Neurosurgery, National Hospital
for Neurology and
Neurosurgery, Queen Square,
London, UK
3
Department of Neurology,
Hospital La Fe, Valencia, Spain
4
Department of Neurosurgery,
University of Texas,
Southwestern, Dallas, Texas,
USA
5
Department of Neurosurgery,
Medical University, Graz, Austria
6
Department of Neurosurgery,
University Hospital, Umea,
Sweden
Correspondence to
Thomas Foltynie, Unit of
Functional Neurosurgery, Sobell
Department of Motor
Neuroscience, Box 146,
National Hospital for Neurology
and Neurosurgery, Queen
Square, London WC1N 3BG,
UK; t.foltynie@ion.ucl.ac.uk
Received 12 January 2010
Revised 7 April 2010
Revised 12 April 2010
Published Online First
22 June 2010
358 J Neurol Neurosurg Psychiatry 2011;82:358e363. doi:10.1136/jnnp.2010.205542
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visualised in each patient using specifically selected pre-operative
stereotactic MRI sequences
10 11
following Leksell frame attach-
ment (Elekta Instrument AB, Stockholm). Target selection for
placement of the deepest contact was performed at the level of
maximal rubral diameter (around 5 mm below the AC PC plane)
using commercially available planning software (FrameLink,
Medtronic, Minneapolis). The STN was visualised as the hypo-
intense signal lateral to the red nucleus. The entry point was
defined at or behind the coronal suture to ensure a trajectory
that would avoid sulci and the ventricular system. The exact
entry and target point were subsequently modified to maintain
a parenchymal trajectory while maximising the length of the
trajectory within the visible STN hypointensity from the
ACePC to target level.
12 13
This was best achieved by refor-
matting images along the planned trajectory. As a result, the
final target point was often located a couple of millimetres
posterolateral to the target point described by Bejjani et al
14
(figure 1). Since the sensorimotor STN is thought to occupy the
supero-postero-lateral portion of the nucleus, this target point
may bring the electrode trajectory closer to the desired func-
tional target.
15
During surgery, brain shift was avoided in several ways.
Minimal CSF loss was achieved by placing the 14-mm burr hole
and 3e4 mm small dural opening on a gyrus rather than
a sulcus, flooding the burr hole with saline irrigation after dural
opening, limiting the time from dural opening to final DBS
electrode implantation and sealing the dural defect with fibrin
glue as soon as the DBS electrode was in situ and before test
stimulation/and or local field potential recording. Performing
surgery in a similar position to that adopted during image
acquisition, with only slight head-up tilt to encourage venous
drainage, may further limit shift by minimising postural
movement of intracranial structures.
Dynamic impedance monitoring was performed while intro-
ducing a 1.5- or 2.2-mm diameter, blunt-tip radiofrequency (RF)
electrode to the target (Leksell RF electrodes, Elekta, Stockholm).
Great care was taken to avoid electrode deviation by contact
with the burr hole or dural edges. A sharp tip probe would
theoretically result in less brain deformation; however, the
authors avoid this technique in view of the potential penetra-
tion, rather than displacement, of intraparenchymal vessels and
resulting haemorrhage. After withdrawal of the RF electrode,
a quadripolar DBS electrode (Model 3389 DBS lead, MedtronicÒ,
Minneapolis) was soft-passed down the same track. The depth
of implantation of the deepest electrode was controlled by
placing a depth stop a defined length along the electrode shaft.
In those patients undergoing surgery under local anaesthesia,
symptoms were assessed for the presence of a micro-lesion
introduction effect. Monopolar stimulation through the
contacts of the DBS electrode was then sequentially performed
to assess for additional therapeutic effect and/or the presence of
side effects (w10 min per side). The electrodes were secured in
place with a skull fixation device (Medtronic burrhole cap or
Stimloc device). Immediately following implantation of the DBS
leads, all patients had a stereotactic MRI scan to confirm the
electrode positions before implantation of the pulse generator.
The perpendicular scalar (Euclidean) distance between the
intended MRI target and the actual position of the implanted
electrode was calculated on the immediate postoperative
stereotactic MRI for each patient. The surgery was not consid-
ered to be finished until the post-operative imaging had
confirmed acceptable placement of the electrodes. Prophylactic
systemic antibiotics (Cefuroxime 1.5 g) were administered intra-
operatively and three more times during the following 24 h.
Frame fixation and imaging took approximately 45 min with an
additional 30e45 min for stereotactic calculations. The typical
duration of bilateral electrode implantation was 2 h for surgery
under general anaesthesia and 3 h under local anaesthesia. All
adverse events were recorded immediately post-operatively and
during subsequent follow-up assessments.
Follow-up
Selection of the optimal stimulation parameters was based on
the acute clinical response to stimulation during the first post-
operative weeks, with further adjustment of parameters as
required, at follow-up visits typically at 1, 3, 6 and 12 months.
To ensure optimal stimulation parameters, all patients under-
went off- and on-medication assessments at their 6e12 months
post-operative visit and then annually thereafter, using the
UPDRS scale. Patients completed post-operative PDQ39 quality-
of-life scales and neuropsychological assessments at their 6e12-
month follow-up visit, and follow-up evaluation of speech was
performed in all patients after 2004.
Figure 1 Top panel: Preoperative stereotactic T2-weighted axial MRI
(1.5T, 2 mm thickness, no gap, TR 3500, TE 90.9) at the level of maximal
rubral diameter (around 5 mm below the ACePC plane). The
subthalamic nucleus (STN) was visualised as the hypointense signal
lateral to the red nucleus. Bottom left panel: The entry and target point
were selected to maintain a parenchymal trajectory while maximising
the length of the trajectory within the visible STN hypointensity from the
ACePC to target level. As a result, the final target point (open circle)
was typically located 2.5 mm posterolateral to the target point originally
described by Bejjani et al (solid circle). Bottom right panel: Post-
operative stereotactic T2-weighted axial MRI at equivalent level
revealing electrode artefact at intended target.
J Neurol Neurosurg Psychiatry 2011;82:358e363. doi:10.1136/jnnp.2010.205542 359
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Data presentation and analysis
The presentation of clinical outcome data includes the median,
the mean and the range of outcomes. Comparisons of baseline
and post-operative UPDRS and PDQ39 scores were performed
using two-sided sign tests to avoid assumptions regarding data
distribution. The motor response to DBS was calculated in two
ways:
1. Percentage improvement in UPDRS III motor score from
baseline to follow-up in the absence of medication¼(Baseline
off-med score)e(Post-operative off-med ON-stim score)/
(Baseline off-med score)3100.
2. Percentage improvement in UPDRS III motor score by
turning stimulation ON at follow-up assessment in the
absence of medication¼(Post-operative off-med, OFF-stim
score)e(Post-operative off-med, ON-stim score)/(Post opera-
tive offemed, OFF-stim score)3100.
Imputation of data was performed among eight patients who
requested not to be assessed in post-operative off-med, OFF-stim
condition, as equal to baseline off-medication score. Composite
sub-scores were derived from the sum of items 32e34 for total
dyskinesia severity.
RESULTS
Demographic data for the 79 consecutive patients are presented
in table 1.
Two patients had undergone unilateral pallidotomy before
their initial consultations with us. In one of the 79 patients, the
procedure was abandoned because of prolonged superficial
bleeding from a cortical vein, and the consequent CSF leakage
resulted in brain shift away from the skull. A decision was taken
not to implant the permanent electrode after haemostasis was
secured. Post-operative recovery was uneventful with no
evidence of haemorrhage on postoperative imaging.
The remaining patients all underwent bilateral STN DBS, 77
during the same operating session. One patient had an
unplanned staged bilateral procedure because of a complex
partial seizure that followed the insertion of the first electrode.
Following surgery, two patients did not have follow-up assess-
ments because of (1) encephalopathy of unknown origin
(presumed to be allergic) following electrode implantation
requiring removal of all DBS hardware a few days later and (2)
death from previously undiagnosed asymptomatic carcinoma
9 months following surgery. The remaining 76 patients all
underwent formal re-evaluation of PD severity after at least
6 months of post-operative follow-up. Where patients had
multiple follow-up assessments available, data were used from
the assessment closest to the first anniversary of their surgery
(median 12 months, mean 14 months (range 6e36 months).
All electrodes were implanted by means of a single brain
penetration, except one electrode where two passes were needed.
The median perpendicular targeting error between intended
stereotactic coordinates and electrode trajectory, calculated from
post-operative stereotactic MR images, was 1.3 mm (mean
1.3 mm, SD 0.6, range 0 to 2.7 mm). An example of one of our
patients’post operative stereotactic MRI scans is shown in
figure 1. The L-dopa equivalent dose at follow-up was reduced
by a mean of 633 mg (39%). The mean stimulation parameters
at follow-up were Left STN 3.0 V, 60
m
s, 139 Hz; Right STN 3.0
V, 6 2
m
s, 139 Hz. Bipolar stimulation was used in 3/152 elec-
trodes, monopolar stimulation for the remainder.
UPDRS
After a median follow-up time of 12 months, the median
improvement in UPDRS III comparing baseline off-medication
scores to follow-up off-medication, ON-stimulation scores was
56% (mean 52%, p<0.0001; see table 2).
There was no significant change in UPDRS III on-medication
score. Comparison of baseline off-medication scores with follow-
up off-medication, OFF-stimulation scores shows a median
decline of 1.5 UPDRS points (mean 3 points, range 28 points
improvement to 35 points deterioration). Significant improve-
ments were seen following STN DBS for UPDRS IV (compli-
cations of L-dopa treatment) as shown in table 3. The median
total dyskinesia severity score (sum of dyskinesia duration,
disability and pain) was 3 pre-operatively (mean 3.15, SD 2.33)
and 1 post-operatively (mean 1.56 SD 1.92) equivalent to
a reduction of 55% (p<0.0001).
PDQ39
Completed PDQ39 quality-of-life data were available from both
pre- and post-operative time periods in a subgroup of 49
consecutive individuals(table 4; these data were not routinely
collected for the first 1 to 2 years of the period studied). For these
individuals, DBS led to a median improvement of 7.9 points
(mean 5.5 points, p¼0.04) in the PDQ39 summary index,
equivalent to an 18% improvement. There were improvements
in the sub-scores; ADL, stigma and bodily discomfort and
a trend towards worsening of communication.
Speech intelligibility
Pre- and post-operative assessments of speech intelligibility were
performed for 49 consecutive patients. The pre-operative mean
“on medication”intelligibility score was 97.3 (SD 7.8). The
follow-up score “on medication and ON stimulation”, had
deteriorated to 84.4 (SD 27.2; p¼0.0003).
Procedure and hardware related adverse events
Among this consecutive series of 79 patients, superficial bleeding
from a cortical vein was encountered in one patient during
surgery. Once haemostasis had been achieved, a substantial
quantity of CSF had leaked from the dural opening, the brain
had fallen away from the skull and a decision was taken not to
implant the permanent electrode. The procedure was, therefore,
abandoned. Post-operative recovery was uneventful with no
new neurological deficit and no haemorrhage visible on post-
procedure scan. A further patient had their electrodes removed
within the first 2 weeks post-operatively due to the develop-
ment of a fluctuating encephalopathy with widespread white
matter signal changes bilaterally following the course of the
electrodes. The remaining “surgical”adverse events are docu-
mented in table 5. One patient died from disseminated malig-
nancy within 9 months of surgery and did not have follow-up
scoring performed. Three patients underwent further surgery
for their PD due to insufficient response from the first operation:
re-positioning of one of the two STN electrodes in one patient
with improvement in clinical effect, and additional bilateral
globus pallidus internus (GPi) electrode placement in two
patients more than 1 year after their STN DBS procedure
Table 1 Demographic data of patients undergoing bilateral STN DBS
Median (Mean, SD, Range)
Sex distribution 49 men, 30 women
Age at surgery 58.9 years, (57.3, 7.7, 34.5e70.2)
Duration of PD symptoms 11.5 years, (13.4, 7.0, 3.8e42.2)
L-dopa equivalent dose 1620 mg per day (1620, 641, 0e3260)
First degree relative diagnosed with PD 12/79 (15%)
360 J Neurol Neurosurg Psychiatry 2011;82:358e363. doi:10.1136/jnnp.2010.205542
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because of persisting severe painful dyskinesias/dystonias.
Neither of these patients has achieved good symptomatic
control despite the additional surgery.
DISCUSSION
To the best of our knowledge, this is the largest published series
of STN DBS performed in a single centre. Baseline patient
demographics in the present study are similar to those operated
in other series in terms of severity and duration of disease.
16e18
Median overall improvement from baseline in the UPDRS III
off-medication motor score was 56% (mean 52%) and median
improvement in PDQ39 Summary index was 7.9 points (mean
5.5 points). The low morbidity of the MRI-guided approach to
surgery employed in this series demonstrates a high standard of
safety while maintaining therapeutic efficacy.
There have been two large randomised controlled trials that
evaluated the outcomes following DBS surgery in comparison to
best medical treatment, one involving patients with STN DBS
16
and the other with patients having DBS in either the STN or
GPi.
17
Among 78 patients with STN DBS aged <75 years, there
was a mean improvement in the off-medication UPDRS III
motor score of 19.6 points (15.1), equivalent to a 41%
improvement, comparing baseline to post operative scores at
6 months.
16
In parallel with this there was a 9.5-point (15.3)
improvement in the PDQ39 summary index, equivalent to an
overall mean improvement of 25% at 6 months, which is
broadly similar to the overall mean improvement of 18%
(median improvement 23.5%) in our patients after 1 year of
follow-up. This trial was conducted across 10 centres in
Germany with STN targeting using either stereotactic MRI,
ventriculography, MER or a combination of these techniques
according to local surgical protocols. Adverse events in this series
included one death from an intra-cerebral haematoma, one
suicide 5 months after surgery and two infections at the stim-
ulator site. The mean improvements in the clinical outcomes
confirm the overall efficacy of the technique, although the wide
SD in mean outcome, as in the current series, suggests
substantial inter-patient variability in response.
The second large randomised controlled trial of DBS
17
included 121 patients who received either STN DBS (n¼60) or
GPi DBS (n¼61). Of note is that this trial included at least 25%
of the patients aged >70 years. All 13 participating sites were
selected because they used MER to help in targeting. Among the
group of patients as a whole, there was a 12.3-point improve-
ment (95% CI 14.3 to 10.3, SD not stated) in the UPDRS III
off medication score at 6 months compared with baseline,
equivalent to 29% improvement in scores. In addition, there was
a 7.7-point improvement in the PDQ39 summary index with
improvements in 7/8 sub-domains. Among this group of
patients, there was one patient death from intracerebral
haemorrhage following the surgery and 16 infections related to
the electrodes or neurostimulator requiring removal of the
hardware.
In a meta-analysis of open label studies including 21 patient
populations,
18
the mean improvement following STN DBS in
the UPDRS motor subscale was 27.6 points (equivalent to 52%
improvement from baseline), and the mean improvement in
quality-of-life was 34.5%. These patients sustained intracranial
haemorrhage in 3.9%, infection in 1.7% and seizures in 1.5%. In
a further meta-analysis including 31 STN studies and totalling
565 patients, an overall improvement of 54% in the UPDRS III
score was identified.
19
The mean improvement in UPDRS III off-
medication scores in the current series is thus in the average
range when compared to that seen in either of the two large
multi-centre trials
16 17
and the meta-analyses of published
data.
18 19
Image-guided surgery and surgical adverse events
The optimal target point within the visualised STN is as yet
undefined. Our targeting strategy often resulted in the final
target point being located a couple of millimetres posterolateral
to the target point described by Bejjani et al
14
(figure 1). Since
the sensorimotor STN is thought to occupy the most superior,
posterior and lateral portion of the nucleus, a more posterolat-
eral target point within the STN may bring the electrode
trajectory closer to the functional target.
15
Table 2 Comparisons of UPDRS III motor scores pre-operatively off- and on-medication, and post-operatively off and on medication/stimulation.
UPDRS-Unified Parkinson’s disease rating scale
Baseline
Mean (SD)
Median
Range
Follow-up
OFF Stim
Mean (SD)
Median
Range
Follow-up
ON Stim
Mean (SD)
Median
Range
Improvement from
Baseline to follow-up ON Stim
Mean (SD)
Median
Range
Mean Per cent (SD)
Median Per cent
Range
Summary data
(p value)
Improvement from
follow-up OFF stim to ON stim
Mean (SD)
Median
Range
Mean Per cent (SD)
Median Per cent
Range
Summary data
(p value)
UPDRS III motor score
off-medication
51.5 (14.9)
51
19 to 88
54.7 (17.6)
51
27 to 100
23.8 (11.2)
21
7to59
27.7 (13.8)
27
3to67
52.0% (20.9)
56.3%
15.8% to 88.5%
Improved n¼75
Worsened n¼1
(p<0.0001)
31.0 (14.5)
30
2to71
55.5% (16.8)
57.7%
7.4% to 87.9%
Improved 76
Worsened 0
(p<0.0001)
UPDRS III motor score
on-medication
14.6 (7.7)
14
2to39
Not assessed 14.5 (8.3)
12
2to41
0.0 (7.97)
1.0
27 to 21
23.4% (91.2)
3.0%
400% to 75%
Improved 37
Unchanged 4
Worsened 33
(p¼0.72)
Not assessed
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Post-operative MRI confirmation of electrode location
confirms the reliability of MRI-guided electrode placement
without MER. There is a paucity of publications that report on
outcome of STN DBS using image-guided techniques.
6
Our data
demonstrate that MER may not be a pre-requisite to ensure
well-placed electrodes that deliver a satisfactory clinical
outcome. Importantly, the adverse event profile seen in this
series compares very favourably with that reported in neuro-
surgical series that used MER,
17 18 20e28
with no infection,
haemorrhage or mortality associated with surgery, in the current
series. The risk of symptomatic haemorrhage inevitably rises
with increasing numbers of micro- or macro-electrode brain
penetrations.
20 21 23 29
Furthermore, since MER significantly
prolongs the procedure, we have been concerned that this
potentially increases the risk of brain shift due to CSF leakage,
which may paradoxically lower the precision of electrode
placement as well as potentially increasing the risk of infection.
None of the patients in this series had visible haemorrhage on
their post-operative imaging. The single patient that suffered
a pulmonary embolus was treated with a vena cava filter, made
a complete recovery and has an excellent response to DBS. Of
the two patients that had peri-operative seizures, one had
a history of previous seizures and the other did not. Neither
patient is on long-term antiepileptic medication or has had
seizures subsequently.
The number of surgical adverse events in our patients is very
low. Nevertheless, the patient that required removal of elec-
trodes warrants further discussion. Post-implant MR images
revealed edema surrounding the entire intra-cerebral course of
both electrodes. This lady had no history of allergy and did not
show any evidence of nickel allergy when subsequently tested.
The early post-operative course was unremarkable for the first
few days but was followed by a fluctuating encephalopathy that
did not respond to oral steroids. The electrodes were removed
and were negative for Gram stain and fungal culture. Subse-
quent management of PD symptoms has been with medical
therapies alone. We are unaware of any previous publications of
this type of reaction to DBS surgery.
Table 3 Comparison of UPDRS part IV sub-scores pre-operatively and
post-operatively
UPDRS IV Baseline
Mean (SD)
Median
Range
Follow-up ON Stim
Mean (SD)
Median
Range
Improvement from
baseline to follow-up
ON stim
Mean (SD)
Median
Range
(p value)
Summary data
Dyskinesia Duration
0¼None
1¼1e25% of day
2¼26e50% of day
3¼51e75% of day
4¼76e100% of day
1.49 (0.85)
1
0to4
0.81 (0.84)
1
0to4
0.69 (0.9)
1
3to1
(p<0.0001)
41 improved
25 unchanged
4 worse
Dyskinesia Disability
0¼not disabling
1¼mildly disabling
2¼moderately disabling
3¼severely disabling
4¼completely disabling
1.11 (1.11)
1
0to4
0.44 (0.81)
0
0to3
0.65 (1.2)
0
3to2
(p¼0.0003)
31 improved
31 unchanged
8 worsened
Dyskinesia Pain
0¼No painful dyskinesias
1¼slight
2¼moderate
3¼marked
4¼severe
0.55 (0.93)
0
(0 to 3)
0.32 (0.72)
0
(0 to 3)
0.23 (1.2)
0
3to3
(p¼0.05)
Improved¼19
Unchanged¼43
Worsened¼8
Early morning dystonia No¼35
Yes¼40
No¼46
Yes¼27
(p¼0.06)
Improved¼24
Unchanged¼35
Worsened¼12
Predictable ‘offs’ No¼4
Yes¼70
No¼37
Yes¼36
(p<0.0001)
Improved¼33
Unchanged¼38
Worsened¼0
Unpredictable “offs” No¼22
Yes¼52
No¼57
Yes¼16
(p<0.0001)
Improved¼35
Unchanged¼34
Worsened¼2
Sudden “offs” No¼34
Yes¼40
No¼62
Yes¼11
(p<0.0001)
Improved¼30
Unchanged¼37
Worsened¼4
Proportion time off
0¼None
1¼1e25% of day
2¼26e50% of day
3¼51e75% of day
4¼76e100% of day
1.82 (0.72)
2
1to4
0.77 (0.81)
1
0to3
1.1 (1.1)
1
4to2
(p<0.0001)
Improved¼49
Unchanged¼19
Worsened¼3
Table 4 Comparison of PDQ39 quality of life scores pre-operatively
and post operatively
Baseline
Mean (SD)
Median
Range
Follow-up (ON-stim)
Mean (SD)
Median
Range
Difference from baseline
to follow-up ON-stim
Mean (SD)
Median
p value
PDQ39 SI 30.2 (13.0)
28.2
5.7 to 59.8
24.7 (15.0)
23.8
5.9 to 78.2
5.5 points (17.3)
7.9 points
p¼0.04
Mobility 50.8 (22.0)
52.5
0to95
40.1 (25.1)
40.0
2.5 to 100
10.7 points (25.6)
12.5
p¼0.08
ADL 38.5 (20.5)
37.5
4.2 to 75
26.2 (19.6)
20.8
0 to 87.5
12.3 points (23.6)
12.5
p¼0.002
Cognition 24.7 (17.8)
18.8
0 to 68.8
21.4 (18.9)
18.75
0 to 87.5
3.3 points (20.1)
6.3
p¼0.12
Communication 23.0 (19.6)
16.7
0 to 66.7
28.9 (21.7)
25
0 to 83.3
5.9 points (21.8)
8.3
p¼0.08
Emotional 21.5 (15.1)
16.7
0 to 62.5
21.3 (18.1)
20.8
0 to 83.3
0.2 points (22.3)
4.2
p¼0.37
Stigma 26.4 (23.0)
25.0
0 to 87.5
14.9 (17.5)
12.5
0to75
11.5 points (26.4)
6.3
p¼0.009
Social Support 12.9 (16.3)
8.3
0 to 66.7
13.7 (19.8)
8.3
0 to 83.3
0.8 points (17.2)
0
p¼0.33
Bodily discomfort 43.5 (24.5)
41.7
0to75
31.0 (22.9)
25
0 to 100
12.5 points (30.2)
8.3
p¼0.0009
SI, Summary Index¼sum of change in each PDQ39 dimension/8; ADL, Activities of Daily Living.
Table 5 Adverse events arising as a result of surgery in
this series
Symptomatic haemorrhage Nil
Asymptomatic haemorrhage Nil
Pulmonary Embolus 1
Misplaced electrode 1
Pneumonia 1
Transient confusion/delirium 7
Seizure 2
Suicide Nil
Scalp erosion 1
Infection Nil
DBS Malfunction Nil
Lead fracture Nil
Lead migration Nil
362 J Neurol Neurosurg Psychiatry 2011;82:358e363. doi:10.1136/jnnp.2010.205542
Research paper
group.bmj.com on April 15, 2011 - Published by jnnp.bmj.comDownloaded from
Several patients in our series developed dysarthria limiting
stimulation settings to those that provide more modest motor
improvements. Outcome measures of improvement in motor
disability using “optimal”stimulation parameters are thus also
influenced by other confounders. In a previous analysis of speech
outcomes following STN DBS, we have reported that speech
intelligibility deteriorates with stimulation among patients with
electrodes situated in a more medial position.
5
We, therefore,
advocate imaging strategies that may further reduce the
observed targeting error and improve reproducibility of electrode
location with respect to the individual radiological anatomy.
This series confirms that MRI-guided STN DBS can lead to
substantial mean improvements in motor disability of PD
patients with improvement in quality of life. Reducing the risk
associated with surgery through meticulous patient selection and
optimal practice should serve as reassurance to patients with PD
who may stand to benefit from this intervention but remain
appropriately cautious about taking risks with their health.
Acknowledgements This work was supported by the Parkinson’s Appeal
registered charity 263064. The work was undertaken at UCLH/UCL who received
a proportion of funding from the UK Department of Health’s NIHR Biomedical
Research Centres funding scheme.
Funding Other Funders: Parkinson’s Appeal.
Competing interests The authors have no competing interests in the publication of
this article.
Provenance and peer review Not commissioned; externally peer reviewed.
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J Neurol Neurosurg Psychiatry 2011;82:358e363. doi:10.1136/jnnp.2010.205542 363
Research paper
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doi: 10.1136/jnnp.2010.205542
online June 22, 2010 2011 82: 358-363 originally publishedJ Neurol Neurosurg Psychiatry
T Foltynie, L Zrinzo, I Martinez-Torres, et al.
and safety
without microelectrode recording: efficacy
MRI-guided STN DBS in Parkinson's disease
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