Table 1 PSA DBS publications: indications, targets, results and side effects

Mundinger, 1977 [1]

7 torticollis, unilateral, stimulation 30-40 minutes.

cZi; in some cases combined with other structures

Good control of the torticollis

No

Brice and McLellan, 1980 [2]

2 MS, bilateral, post-op 6 months

10mm lateral/20mm behind AC/6–8mm below ICL (AC: anterior commissure; ICL: inter-commissural line)

“Striking improvement” in intention tremor

Transient worsening of swallowing, speech, and micturition, all resolved in 3 weeks but dysarthria.

Andy, 1983 [3]

1 PTT, unilateral

7mm lateral/ 8.5mm behind MCP/1mm below ICL (MCP: middle-commissural point)

Complete cessation of tremor

Unknown

Kitagawa et al., 2000 [4]

1 ET and 1 DT, unilateral, intra-op stimulation and post-op 1 week

Zi, 3 mm under the border of the VIM

Abolition of ET; “remarkable” decrease in DT and dystonia

Transient paresthesia, palm hyperhidrosis, anorexia, and disequilibrium

Hooper et al., 2001 [5]

1 PTT, unilateral, post-op 44 months

12mm lateral/ 6mm behind MCP/4mm below ICL

Sustained microtomy effect. No IPG needed.

Shoulder weakness, resolved in 3 days.

Velasco et al., 2001 [6]

10 PD, unilateral, post-op 12 months

Expressed in tenths of the ICL: laterality 5/10, 8/10 behind AC, 1–2/10 below ICL, targeting Raprl

Significant improvement in tremor and rigidity; Mild improvement in bradykinesia.

1 worsening pre-existing depression, 1 transient diplopia, 3 transient dysarthria

Murata et al., 2003 [7]

8 ET, unilateral, post-op 22 months (8-42)

Best 11mm lateral/7.5mm behind MCP/4mm below ICL in Zi and Raprl

Contralateral tremor decreased by 81%

Only stimulation induced that did not affect result.

Nandi and Aziz, 2004 [8]

15 MS, 6 bilateral, 9 unilateral, post-op 15 months in 10 patients

Zi

Contralateral postural tremor decreased by 64%, intention tremor by 36%

Transient paresthesia, mild dysarthria and seizure in 1 and infection in 2 patients.

Plaha et al., 2004 [9]

4 ET, bilateral, post-op 12 months

Medial to the posterior dorsal third of the STN

Total tremor decreased by 80%. 2 patients with severe head tremor completely resolved. No tolerance. Low volt 1.8.

No dysarthria or dysequilibrium.

Kitagawa et al., 2005 [10]

8 PD, unilateral, post-op 24 months

Best contact 10.5mm lateral/5.6mm behind MCP/ 3.2mm below ICL

UPDRS-III improved by 44.3%, tremor by 78.3%, rigidity by 92.7% and akinesia by 65.7%.

Mild adverse events

Plaha et al., 2006 [11]

35 PD, 29 bilateral, 6 unilateral, post-op 6 months

cZi: posteromedial to the post-dorsal STN

cZi better than STN in reducing UPDRSIII by 76%, tremor by 93%, rigidity by 76% and bradykinesia by 65% in cZi vs by 55%, 61%, 50% and 59% in STN.

No complication in Zi No difference in dyskinesia, L-dopa reduction, and stimulation parameters.

Freund et al., 2007 [12]

1 SCA2, bilateral, post-op 2 years

Combined VOP-VIM/Zi-Cerebellar thalamic projection (VOP: ventro-oralis posterior).

Nearly complete cessation of tremor and torticollis by stimulation to distal contacts

No complication mentioned

Hamel et al., 2007 [13]

8 ET, 2 MS, 1 SCA, bilateral, post-op at least 3 months, most of them > 1year

12.7mm lateral/7mm behind MCP/1.5mm below ICL

Reducing intention tremor by 68% to 73%. PSA better than VIM unless limited by side effects

Paresthesia, dysarthria, gait ataxia, unknown number

Herzog et al., 2007 [14]

10ET, bilateral, and 11MS, 6 bilateral, 5 unilateral, post-op at least 4 months

In PSA region, no details

PSA better than VIM in postural and intention tremors reduction, by 64% in ET and by 50% in MS.

Unknown

Carrillo-Ruiz et al., 2008 [15]

5 PD, bilateral, post-op 12 months

Active contacts: 11.5mm/ 6.5mm behind MCP and 4.5mm below ICL

UPDRS III decreased by 65%, tremor by 90%, rigidity by 94%, bradykinesia by 75%

1 deterioration of pre-existing depression, 5 transient somnolence, 1 transient dysarthria

Plaha et al., 2008 [16]

6 ET, 5 PD, 4 MS, 1 CT, 1 HT, 1 DT/bilateral, post-op 12 months

Posteromedial to the posterodorsal STN

PD tremor improved by 92%, rigidity by 77%, bradykinesia by 62%. Tremor improved in ET by 76%; MS, 57%; CT, 60%; HT, 70%; DT, 71%. Low volts

2 transient dysequilibrium, 1 transient dysphagia

Blomstedt et al., 2009 [17]

2DT,1 WC (writer's cramp),1CT, all unilateral, post-op 1 year

Active 10.3mm/6.1mm behind MCP/3.5 below ICL, in PSA

87% tremor reduction

Unknown

Blomstedt et al., 2010 [18]

21ET, 2 bilateral, 19 unilateral, post-op 1 year.

PSA active contact 11.6mm lateral/6.3mm behind MCP/3mm below ICL.

Reducing tremor of upper extremity by 95%, hand function by 87%, improving ADL by 66%.

8 transient expressive dysphasia, 1 transient clumsy hand and leg.

Fytagoridis and Blomstedt, 2010 [19]

27 ET, 8 PD, 2 DT, 1 CT, 1 WC, all unilateral except 4 bilateral, unknown disease, post-op 34 months

Active 12.0mm/6.1mm behind MCP/1.5mm below ICL, all in PSA

24 non-PD tremor decreased by 91%

1 transient hemiparesis, 1 infection, 22% transient dysphasia.

Barbe et al., 2011 [20]

21ET, bilateral 19, 2 unilateral, post-op at least 3 months

26 sub- ICL and 14 above ICL electrodes. The mean sub-ICL 11.3mm lateral/7.2mm behind MCP/1.4mm below ICL, the thalamic 12.6mm lateral/5.7mm behind MCP/1.0mm above ICL.

Sub-ICL stimulation is more efficient than thalamic stimulation but equally effective when patients’ individual stimulation parameters are used.

Paresthesia in 3/26, and dysarthria in 2/26 electrodes

Blomstedt et al., 2011 [21]

4 ET unilateral, one in STN one in cZi, post-op 1-6 years

cZi 9.5-15.5mm lateral/1.3-9.4mm behind MCP/0.2mm above to 6.8mm below ICL

cZi more efficient than STN

Comparable, dysarthria, dystonia, dizziness, blurred vision.

Blomstedt et al., 2011 [22]

5ET, failed VIM, no info on post-op duration except in “years”

cZi, 11.4mm lateral/6.8mm behind MCP/2.9mm below ICL

cZi achieved improvement in tremor control after VIM failed, 57% cZi vs 25% VIM

Unknown

Blomstedt et al., 2011 [23]

68 ET, 34VIM and 34 PSA, only 3 each bilateral, post-op 28 months for VIM and 12 month for PSA.

Vim 13-15mm lateral/6-7mm before PC/0mm on ICL. PSA: posteromedial to the tail of the STN at the level of maxim diameter red nucleus (PC: posterior commissure)

Tremor in the treated hand improved by 70% in VIM and 89% in PSA.

Unknown

Blomstedt et al., 2012 [24]

14 PD, 13 unilateral, 1 bilateral, post-op 18 months

Posterior and medial to the posterior tail of the STN at the maximal diameter of the RN. Active contact 12.6mm lateral/7mm post MCP/2mm below ICL

Tremor reduction by 82.2%, rigidity by 34.3%, bradykinesia by 26.7%

1 stimulation induced side effect, 1 infection

Fytagoridis et al., 2012 [25]

18 ET, 16 unilateral and 2 bilateral, post-op 4 years on average

cZi, 12.0mm lateral/6.3mm behind MCP/2.2mm below ICL, in posterior-medial to STN at the level of the maximal diameter of red nucleus

Improved total tremor by 51.4%, upper extremity by 89.4%, hand function by 78.5%. No increase in stimulation over the course

Mild and transient, 1 hard ware related.