Search or browse years of Parkinsn Email list messages
Mail converted by MHonArc 2.6.10
 
Site Hosting donated by
&
Grant from The Parkinson Alliance

Parkinsn Current Topics

Thalamotomy Pallidotomy and Deep Brain Stimulation 
Adverse Effects and Outcomes
1: Acta Neurochir (Wien) 2000;142(2):169-75

Posteroventral pallidotomy in Parkinson's disease.

Herrera EJ, Viano JC, Caceres M, Costello G, Suarez M, Suarez JC

Service of Neurosurgery, Stereotaxy and Functional Neurosurgery Unit, Cordoba,
Republica Argentina.

OBJECTIVE: We analyse the clinical aspects, results and reliability of
posteroventral pallidotomy (PVP) carried out as treatment for the principal
symptoms and treatment induced complications in patients with Parkinson's
disease (PD). 
PATIENTS AND METHODS: Between August 1995 January 1998, 17
patients with PD were treated surgically, 13 patients with PVP. A pre- and
post-surgical clinical evaluation was carried out. Riechert's Stereotactic
System (MHT, Freiburg, Germany) was used. Ventriculography under stereotactic
conditions was used in the PVP procedures, Laitinen's co-ordinates as anatomical
target, and electrical stimulation for physiological determination. 3 4
radiofrequency lesions were made at 83 degrees C for 20". The mean age was 60
 10.8 years, ages ranging from 45-79 years. 8 (60.5%) of the patients were
male. The cardinal symptoms of the series were bradykinesia and rigidity. The
duration of the illness ranged from 8.6  3.7 years with a range of 4-15
years. 7 (53.8%) presented with a duration of 10 years or more. 6 (46,2%) of the
patients underwent left PVP, the remaining 7 (53.8%) right PVP. Only one patient
received treatment with right PVP and ipsilateral thalamotomy in the same
surgical procedure. The mean post-surgical follow up was 16  7 months, with a
range of 2 to 26 months. 
RESULTS: An up to date evaluation was carried out on
all patients showing significant changes after PVP in UPDRS motor (P < 0.005),
complete rigidity relief (P < 0.005), bradykinesia relief (P < 0.005) and
complete tremor relief (P < 0.005). An important improvement in contralateral
dyskinesia was noted after PVP. A subjective evaluation of the results showed
excellent results in 4 (30.8%) patients, good in 6 (46.2%) and fair in 3 (23%).
No significant correlation was found between age and duration of illness (P =
0.7). Two patients suffered slight side effects, one patient with worsening of
hypophonia whilst the other suffered subjective visual impairment controlled by
normal post operative ophthalmological examinations. There was no peri-operative
mortality. 
CONCLUSION: PVP is considered a safe and effective surgical method
for the treatment of both the principal symptoms of PD and the complications of
DOPA medication.

Publication Types:
Clinical trial

PMID: 10795891, UI: 20254908



2: Brain Cogn 2000 Mar;42(2):231-52

Neurocognitive correlates of stereotactic thalamotomy and thalamic stimulation
in Parkinsonian patients.

Hugdahl K, Wester K

Department of Biological and Medical Psychology, University of Bergen, Norway.
hugdahl@psych.uib.no

In the present paper we have reviewed five different studies that relate to
neuropsychological consequences of stereotactic thalamotomy and thalamic
stimulation in patients with Parkinson's disease. The neuropsychological results
are in a strict sense confined to thalamotomy and thalamic stimulation, although
the more general message of the importance of investigating cognitive functions
before and after surgery applies to other stereotactic techniques for surgical
treatment of movement disorders as well. It is argued in the paper that
stereotactic thalamotomy provides a unique model for basic research on the
neuropsychology of the thalamus, while in return, neuropsychological tests for
cognitive dysfunction after surgery may be the most important clinical
follow-up. Three general conclusions seem warranted from the data. (1)
Parkinsonian patients are impaired on a range of cognitive functions, including
language processing, memory, and executive functions. (2) Stereotactic
thalamotomy does not further impair the patient; instead, we observed
improvement on some tests, particularly verbal memory. (3) In general, there
does not seem to be a laterality effect, depending on which side the thalamotomy
lesion is applied. An exception to this are dichotically presented simple speech
sounds and autonomic responses. In both instances, left-sided brain stimulation
produced enhanced performance, while lesioning the left thalamus impaired
dichotic listening performance. Finally, we present a new hypothesis for a
mechanism behind the thalamotomy effect, based in part on changes in arousal
thresholds. Copyright 2000 Academic Press.

PMID: 10744922, UI: 20211269



3: Neurosurgery 2000 Feb;46(2):390-5; discussion 395-8

Microelectrode-guided thalamotomy for Parkinson's disease.

Linhares MN, Tasker RR

Department of Surgery, Toronto Western Hospital, University of Toronto, Ontario,
Canada.

OBJECTIVE: To describe the outcomes in our first 40 microelectrode-guided
thalamotomies for parkinsonian tremor. 
METHODS: Twenty-four left-sided and 16
right-sided thalamotomies were performed between October 1984 and January 1996;
the mean follow-up period was 35.8 months (range, 1-152 mo). The results were
evaluated retrospectively and semiquantitatively by a disinterested observer
(MNL) and correlated with the quality of the microelectrode recording and the
number and size of radiofrequency lesions made. The first 20 and second 20
procedures were evaluated separately. 
RESULTS: At the last follow-up, the
Unified Parkinson's Disease Rating Scale showed no or virtually no tremor in the
upper limb in 75% of patients or in the lower limb in 73% of patients. No
significant persistent complications were found. These results were achieved at
the expense of having to repeat the procedure on 11 sides (in 5 because of
technical problems and in 6 for no obvious reason). Total or nearly total
abolition of tremor occurred after the first procedure in 40% of the first 20
operations and in 65% of the second 20. Eight of the first 20 procedures and 2
of the second 20 failed for technical reasons. Lesions were made larger in the
second 20 procedures than in the first 20. With the use of an electrode with a
1.1 x 3-mm bare tip for 60 seconds, it seems that lesions had to be created at
60 degrees C or more to produce a successful result. 
CONCLUSION: Thalamotomy with microelectrode recording is an effective procedure 
with which to treat tremor in patients with Parkinson's disease and may involve 
fewer complications than conventional techniques. The procedure appears to 
involve a learning curve.

PMID: 10690728, UI: 20152587



4: N Engl J Med 2000 Feb 17;342(7):461-8

A comparison of continuous thalamic stimulation and thalamotomy for suppression
of severe tremor.

Schuurman PR, Bosch DA, Bossuyt PM, Bonsel GJ, van Someren EJ, de Bie RM, Merkus
MP, Speelman JD

Department of Neurology, Academic Medical Center, Amsterdam, The Netherlands.

BACKGROUND: Deep-brain stimulation through an electrode implanted in the
thalamus was developed as an alternative to thalamotomy for the treatment of
drug-resistant tremor. Stimulation is thought to be as effective as thalamotomy
but to have fewer complications. We examined the effects of these two procedures
on the functional abilities of patients with drug-resistant tremor due to
Parkinson's disease, essential tremor, or multiple sclerosis. 
METHODS: Sixty-eight patients (45 with Parkinson's disease, 13 with essential tremor,
and 10 with multiple sclerosis) were randomly assigned to undergo thalamotomy or
thalamic stimulation. The primary outcome measure was the change in functional
abilities six months after surgery, as measured by the Frenchay Activities
Index. Scores for this index can range from 0 to 60, with higher scores
indicating better function. Secondary outcome measures were the severity of
tremor, the number of adverse effects, and patients' assessment of the outcome.
RESULTS: Functional status improved more in the thalamic-stimulation group than
in the thalamotomy group, as indicated by increases in the score for the
Frenchay Activities Index (from 31.4 to 36.3 and from 32.0 to 32.5,
respectively; difference between groups, 4.4 points; 95 percent confidence
interval, 2.0 to 6.9). After adjustment for base-line characteristics,
multivariate analysis also showed that the thalamic-stimulation group had
greater improvement (difference between groups, 5.1 points; 95 percent
confidence interval, 2.3 to 7.9). Tremor was suppressed completely or almost
completely in 27 of 34 patients in the thalamotomy group and in 30 of 33
patients in the thalamic-stimulation group. One patient in the
thalamic-stimulation group died perioperatively after an intracerebral
hemorrhage. With the exception of this incident, thalamic stimulation was
associated with significantly fewer adverse effects than thalamotomy. Functional
status was reported as improved by 8 patients in the thalamotomy group, as
compared with 18 patients in the thalamic-stimulation group (P=0.01).
CONCLUSIONS: Thalamic stimulation and thalamotomy are equally effective for the
suppression of drug-resistant tremor, but thalamic stimulation has fewer adverse
effects and results in a greater improvement in function.

Publication Types:
Clinical trial
Randomized controlled trial

Comments:
 Comment in: N Engl J Med 2000 Feb 17;342(7):505-7

PMID: 10675426, UI: 20125069



5: Neurology 1999 Nov 10;53(8):1774-80

Neuropsychological and quality of life outcome after thalamic stimulation for
essential tremor.

Troster AI, Fields JA, Pahwa R, Wilkinson SB, Strait-Troster KA, Lyons K,
Kieltyka J, Koller WC

Department of Neurology, University of Kansas Medical Center, Kansas City
66160-7314, USA.

OBJECTIVE: To evaluate short-term effects of unilateral thalamic deep brain
stimulation (DBS) on cognition, mood state, and quality of life in patients with
essential tremor (ET). 
BACKGROUND: Unilateral thalamotomy and thalamic DBS are
effective in alleviating refractory tremor contralateral to the side of surgery.
Thalamotomy can lead to cognitive morbidity, and DBS might be a preferable
surgical intervention given potential avoidance or reversibility of such
morbidity. Although unilateral thalamic DBS is cognitively safe and leads to
quality of life improvement in PD, its neurobehavioral effects in ET are
unknown. 
METHODS: Forty patients with ET were administered a broad
neuropsychological test battery, measures of mood state, and generic and
disease-specific quality of life measures approximately 1 month before and 3
months after surgery (left hemisphere, 38 patients). 
RESULTS: Unilateral thalamic DBS was associated with significant improvements 
in tremor and dominant-hand fine visuomotor coordination. Statistically significant but
clinically modest gains were observed on tasks of visuoperceptual and
constructional ability, visual attention, delayed word list recognition, and
prose recall. Only lexical verbal fluency declined significantly after surgery.
Patients rated themselves as less anxious after surgery, and they perceived
their quality of life as improved significantly. In particular, patients
reported improved quality of life with respect to activities of daily living,
stigma, emotional well-being, and communication. 
CONCLUSIONS: Unilateral
thalamic DBS for ET is cognitively safe and associated with improvements in
anxiety and quality of life in the near term and in the absence of operative
complications. Patients were better able to carry out activities of daily living
after surgery, and they reported improvement in several psychosocial domains of
quality of life.

PMID: 10563627, UI: 20025151



6: Clin Neurol Neurosurg 1999 Sep;101(3):182-8

Cognitive outcome following staged bilateral pallidal stimulation for the
treatment of Parkinson's disease.

Fields JA, Troster AI, Wilkinson SB, Pahwa R, Koller WC

Department of Neurology, University of Kansas Medical Center, Kansas City
66160-7314, USA.

As neurosurgical treatment of parkinsonian symptoms has become increasingly
popular, concern about the cognitive morbidity which may result from such
interventions has risen proportionately. Previous reports of cognitive
difficulties associated with pallidotomy and thalamotomy, especially in
bilateral cases, have provided the impetus for research into chronic electrical
deep brain stimulation procedures which are believed to be safer than ablation.
Given the lack of neurobehavioral research following bilateral deep brain
stimulation procedures, this preliminary study of six Parkinson's disease
patients undergoing staged bilateral pallidal stimulation was undertaken. A
battery of tests assessing attention, executive function, visuomotor
coordination, language, visuoperceptual function, learning memory and mood
revealed no significant change in overall level of cognitive functioning after
either unilateral or bilateral pallidal deep brain stimulation. No significant
declines were observed about three months following bilateral stimulation, and
in fact, significant gains in delayed recall and relief of anxiety symptoms were
noted. It was concluded from this preliminary data that bilateral pallidal
stimulation for the treatment of Parkinson's disease, at least in the absence of
operative complications, offers a cognitively safe alternative to ablation.

Publication Types:
Clinical trial

PMID: 10536904, UI: 20005296



7: Neurol Med Chir (Tokyo) 1999 May;39(5):350-6; discussion 356-7

Long-term results of ventrolateral thalamotomy for patients with Parkinson's
disease.

Moriyama E, Beck H, Miyamoto T

Department of Neurosurgery, Fukuyama National Hospital, Hiroshima.

This study evaluated the long-term outcome for 53 patients with idiopathic
Parkinson's disease treated by stereotactic thalamotomy between 1977 and 1996 at
our institute. Significant reduction of tremor and rigidity of the contralateral
extremities persisted throughout the follow-up period (mean 8.8 years) in 44
patients who underwent unilateral thalamotomy. These effects resulted in
postoperative improvement of activity of daily life (ADL) with reduced dosage of
levodopa. The effect of surgery on akinesia was limited and postoperative
progression of akinesia was related to the postoperative deterioration of ADL.
Multivariate analysis disclosed that the preoperative akinesia score was the
critical factor for poor outcome. Nine patients underwent bilateral
thalamotomies at a mean interval of 56 months. Five patients were obviously
benefited from the second thalamotomy. The only perioperative complication was
large intracerebral hematoma at the lesion site in one patient. This study
confirmed the reliable and persistent effect of thalamotomy. Patients with
Parkinson's disease whose disability is mainly caused by tremor and/or rigidity
will be benefited from this procedure. Second thalamotomy, contralateral to the
initial side, may be indicated if the ADL deteriorates due to the progression of
the symptoms on the non-treated side. Patients disabled by advanced akinesia are
not good candidates for thalamotomy.

PMID: 10481437, UI: 99411051



8: J Neurosurg 1999 Jul;91(1):68-72

Thalamic deep brain stimulation for the treatment of head, voice, and bilateral
limb tremor.

Taha JM, Janszen MA, Favre J

Department of Neurosurgery, University of Cincinnati College of Medicine and
Mayfield Clinic, Ohio 45267-0515, USA. tahaj@one.net

OBJECT: In published series of patients who undergo deep brain stimulation (DBS)
of the thalamus the effects of unilateral stimulation on contralateral limb
tremor have been reported. The authors detail their experience with bilateral
thalamic DBS in the treatment of head, voice, and bilateral limb tremor and
compare it with earlier studies of unilateral stimulation. 
METHODS: Twenty-three patients (six with Parkinson's disease, 15 with essential 
tremor, and two with multiple sclerosis) underwent 19 bilateral DBS procedures 
(nine staged, 10 simultaneous) and four procedures contralateral to thalamotomy 
to control tremor of the head in 10, voice in seven, and limbs in 20 patients. 

Limb tremor improvement was graded as follows: 
4, no tremor; 
3, stress-induced tremor; 
2,functional improvement; 
1, no functional improvement; and 
0, persistent tremor.

Improvement of head or voice tremor was graded as follows: 
4, greater than 75%;
3, between 50% and 75%; 
2, between 25% and 50%; 
1, less than 25%; and 
0, no improvement.

The mean follow-up period was 10 months. 
Twenty-two patients (96%)
demonstrated improved tremor at the last follow-up review. 

Of 20 patients with bilateral limb tremor, 
17 (85%) improved to Grades 3 and 4, 
two patients (10%) with multiple sclerosis improved to Grade 2, and 
one (5%) exhibited tremor recurrence 8 months later. 

Nine (90%) of 10 patients with severe head tremor improved to Grades 4 or 3. 
Six (86%) of seven patients with voice tremor improved to Grade 3. 
Seven patients (30%) developed dysarthria, and 
seven (30%) developed disequilibrium; symptoms reversed in the majority of 
patients after the stimulation parameters were changed. 
One patient (4%) developed mild memory decline. There were no deaths. 
CONCLUSIONS: The following findings are reported:
1) bilateral thalamic DBS and stimulation contralateral to thalamotomy are safe;
2) staging the procedure does not reduce the risk of dysarthria or gait
disequilibrium; and 
3) head and voice tremor are primary indications for bilateral DBS.

PMID: 10389882, UI: 99316744



9: J Neurol Neurosurg Psychiatry 1999 Jun;66(6):772-5

Stereotactic thalamotomy in the treatment of essential tremor of the upper
extremity: reassessment including a blinded measure of outcome.

Zirh A, Reich SG, Dougherty PM, Lenz FA

Departments of Neurosurgery and Neurology, Johns Hopkins Hospital, Baltimore MD
21287-7713, USA.

The effectiveness of high frequency stimulation of the thalamic nucleus
ventralis intermedius (Vim-HFS) for treatment of tremor has been studied by
blinded assessment. The effectiveness of thalamotomy for essential tremor of the
upper extremity by use of a blinded measure of outcome is now reported.
Thalamotomy was performed in 21 patients (three operated on bilaterally) with
medically intractable, essential tremor. Assessments of function,
handwriting/drawing, and tremor amplitude were done before and at 3 and 12
months after surgery. The handwriting/drawing score was rated by a neurologist
blinded to patient identity, laterality, and operative status. By comparison
with baseline, both the total functional score and the total score from blinded
assessment of handwriting/drawing improved significantly at 3 and 12 months
after surgery. The two scores were significantly correlated, suggesting that the
blinded assessment is a good predictor of a total disability from tremor.
Complications after unilateral thalamotomy included transient dysarthria,
permanent perioral numbness, and permanent mild disequilibrium in one patient
each. Permanent mild dysarthria occurred in two of three patients operated
bilaterally. Thus a blinded assessment of outcome establishes that unilateral
thalamotomy is an effective, safe procedure for the treatment of essential
tremor.

Comments:
 Comment in: J Neurol Neurosurg Psychiatry 1999 Jun;66(6):702

PMID: 10329753, UI: 99262871



10: Br J Neurosurg 1998 Dec;12(6):559-62

Vim thalamotomy for the relief of the intention tremor of multiple sclerosis.

Critchley GR, Richardson PL

Department of Neurosurgery, Manchester Royal Infirmary, Manchester, UK.

We have reviewed the outcome of patients who have undergone thalamotomy for the
intention tremor of multiple sclerosis (MS). Twenty-four patients underwent 29
procedures between 1988 and 1995. These patients were assessed for the degree of
disability due to MS and for the impairment of arm function due to the tremor.
Preoperative, postoperative and last follow-up score (mean 2.2 years) were
determined for arm function following thalamotomy. Patient satisfaction, where
expressed, was recorded. Twenty-three procedures (79%) resulted in immediate
improvement in arm function. Thirteen complications were recorded. Postoperative
fatigue was demonstrated after seven procedures. Sustained benefit was seen
after 18 procedures (62%). Out of 23 patients whose opinions are recorded four
were enthusiastic and 10 satisfied with the outcome. We conclude that, despite
severe disability, a majority of patients with intention tremor of MS may still
benefit from thalamotomy and are satisfied with the results.

PMID: 10070467, UI: 99169620

Mov Disord 1999 Sep;14(5):847-50 Related Articles, Books, LinkOut  


Efficacy of unilateral deep brain stimulation of the VIM nucleus of the thalamus 
for essential head tremor. 

Koller WC, Lyons KE, Wilkinson SB, Pahwa R 

Department of Neurology, University of Kansas Medical Center, Kansas City 66160-7314, USA.

Essential tremor is a common movement disorder. Deep brain stimulation of the VIM 
nucleus of the thalamus has been reported to be efficacious for reducing essential 
hand tremor. The effect of deep brain stimulation of the thalamus on essential head 
tremor has not been well studied. Therefore, we evaluated the effect of DBS of the 
thalamus in 38 patients with essential head tremor. Head tremor scores prior to 
surgery were compared with scores at 3, 6, and 12 months postimplant with 
stimulation "on" and "off." The 3-month evaluations were blinded for 24 patients 
and all others were open-label. There was a significant improvement in head tremor 
at all postimplant evaluations compared with baseline. Essential head tremor can be 
reduced with deep brain stimulation of the VIM nucleus of the thalamus and, pending 
the results of other controlled trials, should be considered as a treatment option for 
patients with disabling essential head tremor unresponsive to medication.

Publication Types: 
Clinical trial 
Randomized controlled trial 

PMID: 10495050, UI: 99423241 


Return To Index of Current Parkinson's Topics