Table 1.

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

Series (reference number)	Patients/procedures/time to assess	Target and/or stereotactic parameters	Results	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.