Spinal cord stimulator implantation
paresthesia
SECONDARY, INFILTRATION, APPENDIX, PARESTHESIA
The spinal cord stimulator system consists of an implantable pulse generator (IPG) (PrimeADVANCED™ SureScan® MRI Medtronic), a single lead (Vectris Compact™ SureScan MRI Medtronic) and a patient programmer (myStim Patient Programmer & ADVANCED™ Antenna Medtronic). The spinal cord stimulator implantation will take place in an operating room in accordance with national guidelines concerning aseptic preparations. During the procedure the patient is asked to lie in a prone position to increase the thoracic kyphosis. Moderate sedation is applied using a combination of propofol and remifentanil, secondary field blocks and wound infiltration with local anesthetics will be used to provide analgesia. Sedation levels and vital signs are controlled and monitored by an experienced nurse. A Tuohy needle is used to enter the epidural space at the level of thoracic vertebrae (Th) 7–8. Entrance into the epidural space is gained using loss of resistance and confirmed by advancing a guide wire through the Tuohy needle under fluoroscopic guidance. Next the guide wire is removed and the lead is advanced into the epidural space with the cephalad tip positioned paramedian to the left side at the level of C7‐Th1 using fluoroscopic guidance. To determine if the position of the lead is correct sedation is temporarily lifted and using an external programmer (Intellis Wireless External NeuroStimulator (WENS), Samsung Programsystem and Communicator) stimulations are given. The aim is to achieve a paresthesia coverage of the target area (left side of the chest) of at least 80% and subtle modifications of the lead position are performed to reach the optimal coverage based on feedback from the patient during test stimulation. When the optimal position of the lead has been determined the lead is fixated at the thoracodorsal fascia, subcutaneously tunneled and connected to the IPG pocket. The usual subcutaneous position of the IPG is the left buttock. After the implantation has been completed the patient is monitored on the ward and an X‐ray is made to confirm the position of the lead. Depending on the randomization the correct settings will be input by the unblinded study nurse (Appendix 