Spinal Cord Stimulation: The Trial Period

Prior to the surgical implantation of a spinal cord stimulator, the patient has a 1-week trial using an external stimulator. The purpose of the trial is to evaluate if the application of spinal cord stimulation effectively reduces the patient’s pain before committing to permanent implantation.

The trial is part of a two-step process:

• Step 1: To evaluate the person’s medical condition and conduct a detailed review of their medical history.
• Step 2: To temporarily place the leads (wires) in the spinal epidural space (space surrounding the spinal cord) and monitor if stimulation relieves the patient's pain and symptoms.

The trial procedure involves placing the wires (leads) in the epidural space near the spinal cord and connecting them to an external stimulator that is carried in a fabric pouch worn around the patient’s waist.  

The trial is deemed successful if more than 50% pain relief is experienced along with improvements in daily function. ¹ Sitzman BT, Provenzano DA. Best practices in spinal cord stimulation. Spine. 2017;42(14):S67-S71. doi:10.1097/BRS.0000000000002220

Preparing for a Spinal Cord Stimulator Trial

The treating physician will advise the patient to prepare for the trial by taking certain actions, such as:

• Stop or reduce the intake of certain medications and/or supplements, such as NSAIDs and blood-thinning medication, 2 to 7 days before the procedure to reduce the risk of excessive bleeding
• Not consume any food or drink on the day of the procedure
• Schedule transportation to return home after the procedure 

Patients are also encouraged – or required - to quit using all forms of nicotine, including smoking, vaping, and chewing tobacco, as nicotine is known to impair tissue healing and increase the risk of complications and poor surgical outcomes. ² De La Cruz P, Fama C, Roth S, et al. Predictors of Spinal Cord Stimulation Success. Neuromodulation. 2015;18(7):599-602. doi:10.1111/ner.12325

Step-by-Step Procedure

The medical procedure for a spinal cord stimulation trial is performed in a doctor’s office or a surgical center. The procedure is generally painless due to the use of local anesthesia and takes about 30 to 90 minutes to complete. 

Procedures vary somewhat with the type of stimulation device used, but these are the typical steps:

• Local anesthesia is injected into the target area in the neck or lower back, and sometimes, medication for mild sedation may be administered through an intravenous line to reduce anxiety. 
• A tube-like needle is inserted through the target area, to reach the spinal epidural space – an area surrounding the spinal cord containing a rich network of nerves. Thin, insulated wires, called leads, are threaded through the needle into the epidural space. For accurate placement, the needle and leads are inserted under fluoroscopic (live-x-ray) guidance. 
• The leads are connected to an external stimulator device and electric impulses are passed through the leads. 
• The patient is asked for feedback on the specific areas where pain relief is required. If the electric impulses produce a tingling sensation (paresthesia) in the areas of pain, it indicates correct placement of the leads. If not, the leads are repositioned until the patient confirms the correct placement.  
  • This type of feedback is only required if a low-frequency stimulator is used. High-frequency stimulators do not produce tingling sensations and patient feedback is not required for lead placement. 
  • For patients who receive sedation, the medication is stopped during the feedback session and resumed after the patient has confirmed pain relief.
• The leads are secured to the patient’s back or chest area with medical tape.
• The stimulator is placed in a pouch worn around the patient’s waist or held in place with medical tape.

The patient is given time to recover from the sedation and monitored by a nurse or trained healthcare professional during this time. 

Prior to being discharged, individuals are instructed on how to use the controller to send electric pulses to the nerves in the spine. 

Next Steps After the Trial Procedure

Patients are required to track which stimulation settings are used at different times and how well the pain is relieved. If pain is not relieved, the doctor should be contacted right away for device reprogramming or adjustment of leads.

Specific instructions regarding treatment site monitoring, activity restrictions, and activity recommendations are provided to the patient during the recovery period. 

Any concerning symptoms, such as severe pain, swelling, bleeding, and/or discharge at the treatment site must be reported to the treating physician.