Bilateral Pallidotomy

Laitinen (57) and Iacono et al. (70) reported early good outcomes in 12 and 10 bilaterally operated patients, respectively. There are, however, concerns regarding permanent cognitive and bulbar side effects of bilateral pallidotomy, which have been confirmed in a study of four patients in whom bilateral pallidotomy was performed (71). Despite a 40% improvement in motor UPDRS scores and resolution of dyski-nesia, one patient developed dysarthria, dysphagia, and eyelid opening apraxia,

TABLE 1 Summary of Selected Large Pallidotomy Series in Order of Study Size3

Surgical

Main clinical

Follow-up

Akinesia

Tremor

Gait

Dyskinesia

Overall

Overall

Author

n

method

assessment

interval

4%

4%

4%

4%

mortality%

morbidity%

Laitinen (57)

259b

CT/MRI + MES

"Fair, good, poor"

<48 hr

82% "good"

Not given

Not given

0

7

Kondziolka

58

MRI + MES

UPDRS

6-24 mo

24

50

0

40

0

7

et al. (47)

lacono

55

MRI+Ventricu

"Minor, good

1-24 mo

"Excellent"

"Good"

"Excellent"

"Excellent"

0

7

et al. (46)

lography+MES

or excellent"

Jankovic

41

MRI + MER + MES

MT

3 mo

24

Not given

Not given

Not given

Not given

Not given

et al. (55)

Lang

40

MRI + MER + MES

UPDRS+Goetz

3-24 mo

43

54

42 transient

83

0

38

et al. (58)

Alterman

34

MRI + MER + MES

UPDRS+timed

6 mo

50%

Not given

Not given

"Effectively

0

10

et al. (50)

motor tests

relieved"

Masterman

32

MRI + MER + MES

UPDRS

3-6 mo

23 (B)

43 (B)

30

61 (B)

0

16

et al. (59)

Hirai

28

MRI + MER + MES

"Fair, good or

6 mo

Improved (B)

Dramatic

Improved (B)

0

0

et al. (54)

excellent"

in 8

de Bie

26

Ventriculography

UPDRS + Goetz

5 mo

33

83

38

50

0

50

et al. (52)

Shannon

26

MRI + MER + MES

UPDRS

6 mo

26 A+T+R

0

73

4

30

et al. (60)

Samuel

26

CT+MER+MES

UPDRS

3 mo

24c

33c

7

67

8

58

et al. (27)

Johansson

22

CT/MRI + MES

UPDRS

12 mo

0

0

0

33

0

19d

et al. (56)

v/VAS PLM

Samii

20

CT+MES

UPDRS+GOETZ

24 mo

0

90

0

83

5e

5f

et al. (48)

+ PPT

Dalvi

20

CT-MRI fusion

UPDRS

3-12 mo

22 + R

62

0

71

0

45

et al. (51)

+ MER+MES

Fine

et al. (61)

20

MRI + MER + MES

UPDRS+Goetz

66 mo

18%

65%

43%

71%

Not given

Not given

Baron

15

CT/MRI + MER

UPDRS

12mo

>503

100 in

Not given

100 in

0

20

et al. (49)

+ MES

7/8 cases

9/10 cases

Fazzini

11

CT/MRI + MER +

UPDRS

12—48 mo

43

Not given

Not given

"Did not

Not given

Not given

et al. (53)

MES

return"

Laitinen

38

CT+MES

Writing, drawing,

2-71 mo

>40 in

Excellent

>233

"Greatly

0

22

et al. (45)

walking in a circle

35/363

in 26/32

improved"

Note-. For comparison, the original series of Laitinen is at the bottom.

aSome studies with different patient numbers from the same institutions have overlapping samples. bSome patients had Parkinson-plus syndromes and others had combined pallidotomy and thalamotomy. °Marginally significant result.

dOne patient developed anarthria and two patients required re-operation as they had no benefit from the first pallidotomy. eOne death two weeks postoperatively secondary to ipsilateral intracerebral hemorrhage. 'One patient required re-operation as had no benefit from the first. 9Figure calculated from a graph in manuscript

Abbreviations: n, number of patients; MES, macroelectrode stimulation at target site; MER, microelectrode recording at target site; MT, finger movement time between two adjacent targets; Goetz, the Goetz dyskinesia rating scale; A%, % change; A+T+R, combined score for akinesia, tremor, and rigidity reported; +R, combined score with rigidity reported; v/VAS, video and visual assessment scale; PLM, electronic recording of posturolocomotion manual test; PPT, Purdue pegboard test; (B), assumed bilateral as no distinction made between contralateral and ipsilateral scores.

another developed abulia, and a third developed mental automatisms. Scott et al. (30) described hypophonia, increased salivation, and reduced verbal fluency, following bilateral simultaneous pallidotomy. An open-labeled trial of bilateral simultaneous pallidotomy compared with unilateral pallidotomy plus DBS had to be halted early, as all three patients with bilateral lesions developed deterioration in speech, swallowing, salivation, depression, apathy, freezing, and falling (72). In another series, staged bilateral pallidotomy was associated with a deficit in speech in four patients: one patient had a decline in memory and there were three cases of cerebral infarction (73). These results are similar to the study of De Bie et al. (74) who showed that seven out of 13 patients developed dysarthria and one suffered a severe delayed infarction. Further, a reduced response to levodopa has been documented in a small number of patients undergoing bilateral staged pallidotomy (73).

These results are in contrast to the milder side effects reported in one series of 14 patients who underwent staged bilateral pallidotomy, in whom no overall effect on speech or cognitive function was detected six months postoperatively, but five had mild hypophonia, two had transient confusion, two had deterioration of gait, and one had deterioration of a pre-existing dysarthria postoperatively (75). A larger series of 53 bilaterally operated patients, combined from U.K. and Australian centers, has also been presented with full follow-up of a subgroup of 17 patients for 12 months (76). Major deterioration in speech (defined as a two-point decline on the UPDRS subset score) occurred in 8% of bilaterally operated patients compared with 4% of unilaterally operated patients, although the study was not specifically designed to compare the two procedures. Similarly, postoperative major deterioration in salivation occurred in 13% and 10% of bilaterally and unilaterally operated patients, respectively. Gait freezing while on and handwriting each deteriorated with a frequency of 11% in the bilaterally operated group, and medically unresponsive eyelid opening apraxia occurred in 6%. Dysphagia was not reported. The authors suggest that these relatively low rates of complications may be attributable to the placement of a smaller lesion (100 mm3) in the medial pallidum contributing to the lesser affected hemibody compared with the medial pallidum corresponding to the worse-affected hemibody (150 mm3). Complications were only defined according to their occurrence on the UPDRS rather than by using specific questions designed to assess their presence and severity. Additionally, precise lesion locations and cognitive results were omitted. The question of safety and timing of bilateral pallidotomy, therefore, currently remains controversial and this procedure has not been undertaken by many groups. It is likely to continue to fall out of favor, especially where bilateral DBS is available as an alternative.

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