Correspondence
Pallidotomy in Advanced Parkinson's Disease
N Engl J Med 1998; 338:262-264January 22, 1998
- Article
To the Editor:
In the October 9 issue, Lang et al.1 report on the effects of posteroventral medial pallidotomy in 40 patients with advanced Parkinson's disease. Despite the conclusion that this is an effective treatment, none of the patients had improvements above the level of their optimal motor performance in the preoperative phase. The analysis of complications excluded four patients in whom no lesions were made. One of these patients had a surgically induced intracerebral hemorrhage, and another had an exacerbation of paranoia. Two other patients were excluded because the surgeons could not localize the pallidum. Most investigators would characterize the problems in the first two cases as complications, and the problems in the latter two as treatment failures. If you add the 4 patients who were excluded to the 14 listed as having persistent adverse effects, the dangers of this procedure become more evident.
The challenge in treating advanced parkinsonism is to understand why some patients have alterations in dopamine receptors leading to cycling, on–off phenomena, and dyskinesias that do not respond to decreases in the levodopa dosage without increases in the parkinsonism. The answer to this question does not lie in repeating the mistakes of earlier generations by making destructive lesions in a degenerating brain.
1 ReferencesLorne Ryan, M.D.
500 S. University, Little Rock, AR 722051
Lang AE ,Lozano AM ,Montgomery E ,Duff J ,Tasker R ,Hutchinson W . Posteroventral medial pallidotomy in advanced Parkinson's disease. N Engl J Med 1997;337:1036-1042
Full Text | Web of Science | Medline
To the Editor:
Lang et al. are careful to point out that pallidotomy is not appropriate for all patients with advanced Parkinson's disease and that it should be limited to those with severe levodopa-induced dyskinesias and those disabled by off-period symptoms. The authors also state that patients with compromised neuropsychological function should not undergo this procedure because of the substantial risk of further cognitive decline. Other centers reporting on their results with pallidotomy have also reported improvement in dyskinesias but have not noted much improvement in off-period scores on the Unified Parkinson's Disease Rating Scale. There is a growing consensus that the role of pallidotomy is to treat intractable drug-induced dyskinesias.1 The adverse effects of the surgery are substantial, and the authors note that 25 of the 40 patients had one or more adverse effects and that 14 had one or more persistent adverse effects. This is surgery that should not be undertaken lightly.
1 ReferencesWilliam J. Weiner, M.D.
University of Miami School of Medicine, Miami, FL 33101Author/Editor Response
The authors reply:
To the Editor: Dr. Ryan's conclusion about efficacy ignores the two primary results of our study of pallidotomy in advanced Parkinson's disease: the off-period symptoms and disability were significantly improved and remained so over the two-year follow-up period, and disabling levodopa-induced dyskinesias, which can substantially compromise “optimal motor performance,” were markedly reduced. We agree that it would be preferable not to have to make a destructive lesion in an already diseased brain. However, until more effective medical therapies become available, many patients will remain extremely disabled by off periods and dyskinesias. It is in these patients, whose disability is sufficiently great that they cannot wait for further advances in our understanding, that cautious use of pallidotomy may result in substantial improvements.
We provided all information on our 40 consecutive patients treated prospectively. We acknowledged the intracerebral hemorrhage as a complication in one case. The exacerbation of paranoia in another case was secondary to intraoperative fatigue. For the safety of the patient, the surgery was halted, and the patient quickly returned to his base-line psychological state. We chose not to call the other two cases in which lesions were not made treatment failures; we do not know whether making lesions in these patients would have improved their parkinsonism, and classifying them as failures might have led to an inappropriately negative conclusion. These patients were two of our earliest, and subsequent experience might have allowed us to make lesions in them successfully. We attempted to be all-inclusive in our reporting of other adverse effects. In all the patients with lesions except one (who had worsening of dementia), the complications were mild and were far outweighed by the benefit obtained. Thus, 97 percent of the patients who underwent pallidotomy said that they had obtained a worthwhile benefit and would, in retrospect, undergo the procedure again.
Finally, although we agree with Dr. Weiner that there is a general consensus that the main effect of pallidotomy is on levodopa-induced dyskinesias, the results of our study and several others do not support his impression that there is little improvement in off-period parkinsonism.1-3 Our report emphasized the need for caution in selecting patients with specific types of predominant off-period disability, since the improvement in ambulatory symptoms waned within three to six months after surgery in our study. On the other hand, the improvement in contralateral off-period parkinsonism and levodopa-induced dyskinesias remained significant during at least two years of follow-up. For these reasons, we are cautiously optimistic about the benefit of this surgery in carefully selected patients.
3 ReferencesAnthony E. Lang, M.D.
Andres M. Lozano, M.D.
Toronto Hospital, Toronto, ON M5T 2S8, Canada1
Dogali M ,Fazzini E ,Kolodny E , et al. Stereotactic ventral pallidotomy for Parkinson's disease. Neurology 1995;45:753-761
Web of Science | Medline2
Baron MS ,Vitek JL ,Bakay RA , et al. Treatment of advanced Parkinson's disease by posterior GPi pallidotomy: 1-year results of a pilot study. Ann Neurol 1996;40:355-366
CrossRef | Web of Science | Medline3
Kishore A ,Turnbull IM ,Snow BJ , et al. Efficacy, stability and predictors of outcome of pallidotomy for Parkinson's disease: six-month follow-up with additional 1-year observations. Brain 1997;120:729-737
CrossRef | Web of Science | Medline
