Table 3 Demographic data and complications rates taken from the literature.

	Beric et al7	Kondziolka et al8*	Oh et al9	Umemura et al10	Limousin et al6*	Lyons et al11	This study
No of patients	86	66	79	109	111	80	262/180
No of electrodes	149	66	124	179	135	155	472/325
No of surgeries	NG	100	NG	NG	NG	160	526
Follow‐up time	3.5 years†	29 months‡	33 months§	20 months§	12 months†	5 years†	35.3 months§
Aborted procedures	3.5%	—	0.9%	—	0.9%	4.9% [2.5%]	1.9% [1.0%]
Mortality	—	—	—	1.8%	—	—	—
Morbidity	6%	NG	1.3%	4.6%	—	—	0.4%
SURGERY
ICH	3.3%	1.5%	3.6% (2.3%)	3.6% (2.2%)	2.7% (2.2%)	1.2% (0.6%)	0.4% (0.2%)
Extracranial haemorrhage	—	—	—	—	1.8%	—	2.4%
Venous infarction	—	—	—	0.9% (0.6%)	—	—	—
Seizure	2.3%	—	—	0.9%		1.2% [0.6%]	—
CSF fistula	—	—	1.3%	0.9% (0.6%)	—	—	0.8% (0.4%)
INFECTION
Total	1.2%	10.6%	15.2%	3.7% [2.2%]	1.8%	6.2% [3.8%]	8.3% [2.9%]
Hardware removed	—	6.0%	13.9%	3.7%	1.8%	6.2% [3.8%]	6.7% [2.3%]
HARDWARE
Lead fracture	—	15.2%	5.1%	—	—	2.5% (1.3%)	1.7%
Lead migration	3.5% (2.0%)	1.5%	5.1%	—	—	6.3% (3.2%)	2.8% (1.5%)
Extension wire**	3.5%	—	—	—	—	2.5%	1.1%
IPG malfunction	1.2%	1.5%	3.8%	—	—	13.8%	—
Local discomfort	1.2%	—	—	—	—	Some patients	6.7%*
Others††							1.7%*

ICH, intracranial haemorrhage; IPG, implantable pulse generator; NG, not given. Only studies which explicitly addressed complications and had analysed more than 50 patients were taken into consideration.

Frequencies are given as %/patient, (%/electrode) or [%/no of operations].

*Thalamic targets only.

†Time period.

‡Average.

§Mean values.

**Summarising malfunction, migration or break.

††Summarising minor events such as skin ulceration or seroma.