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Posteroventral Medial Pallidotomy in Advanced Parkinson's Disease
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Background
Posteroventral medial pallidotomy sometimes produces striking improvement
in patients with advanced Parkinson's disease, but the studies to date have
involved small numbers of patients and short-term follow-up.
Methods
Forty patients with Parkinson's disease underwent serial, detailed
assessments both after drug withdrawal ("off" period) and while taking
their optimal medical regimens ("on" period).
All patients were examined preoperatively, and 39 were examined at six
months; 27 of the patients were also examined at one year, and 11 at two
years.
Results
The percent improvements at six months were as follows: off-period score
for overall motor function, 28 percent (95 percent confidence interval, 19
to 38 percent), with most of the improvement in the contralateral limbs;
off-period score for activities of daily living, 29 percent (95 percent
confidence interval, 19 to 39 percent); on-period score for contralateral
dyskinesias, 82 percent (95 percent confidence interval, 72 to 91 percent);
and on-period score for ipsilateral dyskinesias, 44 percent (95 percent
confidence interval, 29 to 59 percent).
The improvements in dyskinesias and the total scores for off-period
parkinsonism, contralateral bradykinesia, and rigidity were sustained in
the 11 patients examined at two years. The improvement in ipsilateral
dyskinesias was lost after one year, and the improvements in postural
stability and gait lasted only three to six months.
Approximately half the patients who had been dependent on assistance in
activities of daily living in the off period before surgery became
independent after surgery. The complications of surgery were generally well
tolerated, and there were no significant changes in the use of medication.
Conclusions
In late-stage Parkinson's disease, pallidotomy significantly reduces
levodopa-induced dyskinesias and off-period disability. Much of the benefit
is sustained at two years, although some improvements, such as those on the
ipsilateral side and in axial symptoms, wane within the first year. The
on-period symptoms that are resistant to dopaminergic therapy do not
respond to pallidotomy.
N Engl J Med 1997;337:1036-42.
Anthony E. Lang, Andres M. Lozano, Erwin Montgomery,
Jan Duff, Ronald Tasker, William Hutchinson
Division of Neurology, Toronto Hospital, Toronto, Ont, Canada
Department of Neurology, University of Arizona, Tucson AZ USA
Copyright 1997 by the Massachusetts Medical Society
The New England Journal of Medicine/October 9, 1997/Vol 337, No 15
<http://www.nejm.org/public/1997/0337/0015/1036/1.htm>
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