Percutaneous Peripheral Nerve Stimulation (Neuromodulation) for Postoperative Analgesia: A Feasibility/Proof-of-Concept Study
Phase: NA
Conditions: Postoperative Pain
Sponsor: University of California, San Diego

Percutaneous Peripheral Neuromodulation for Postoperative Analgesia 
 
NCT:  NCT0289810 
 
Date:  05/17/2018 
 
 

Written, informed consent will be obtained using an IRB-approved ICF prior to any study 
procedures.  Lead insertion may occur up to 2 weeks prior to surgery within the CTRI or 
orthopedic clinic, or the morning of surgery in the CTRI or regional anesthesia induction area (it 
just depends on subject and surgeon preference, as well as logistical issues such as the time of 
the surgery and availability of the investigators).  Baseline muscle strength will be measured 
with a pressure transducer. 
 
Preoperative lead insertion (approximately 1-3 hours).  A percutaneous, helically-coiled, 
insulated electrical lead will be inserted via an introducer needle at least 2 cm proximal or distal 
to the perineural catheter site along the target nerve using real-time ultrasound guidance: 
 
Surgical Procedure Location Perineural Catheter Location Electrical Lead Location 
Shoulder 
Interscalene Interscalene, supraclavicular, or suprascapular 
At or distal to the elbow 
Infraclavicular Interscalene, supraclavicular or terminal nerve(s) 
Foot or ankle Popliteal-sciatic [adductor canal optional] 
Subgluteal-sciatic [femoral optional] 
Knee or distal thigh 
Adductor canal [popliteal-sciatic optional] Femoral [subgluteal-sciatic 
optional] 
 
It will be optional for a conducting probe to be used prior to lead insertion—this allows 
identification of the optimal lead tip location relative to the target nerve by passing electrical 
current via the insulated probe.  The desired end point is a pleasant paresthesia in the 
distribution of the target nerve reported by the subject.  If used, the probe will be completely 
withdrawn following target location identification, and a lead subsequently inserted to the 
target location.  Following needle removal, the percutaneous helical lead will have electric 
current passed using the SPRINT (SPR Therapeutics, Cleveland, OH) pulse generator to ensure 
accurate placement (a pleasant paresthesia in the distribution of the target nerve).  It will be 
replaced, if necessary.  The pulse generator will then be removed and the lead affixed to the 
skin using an occlusive dressing. 
 
With the subject’s permission we may photograph or videotape the procedures described 
above for educational, training, or publication purposes.  The photos or video will focus only on 
the lead insertion site and affected limb.  Ultrasound images from the procedure may also be 
collected.  Every effort will be made to protect the subject’s privacy and the photos or video will 
not include the subject’s face or any other personal identifiers such as birthmarks.  Subjects and 
their caretakers will be trained in device care and management, and given written instructions 
as well.  Following successful lead insertion, a perineural catheter may be inserted, if the 
patient desires a catheter (with normal saline injection and not local anesthetic via the inserting 
needle).  This will be used to deliver perineural local anesthetic as a rescue analgesic method 
postoperatively in case the SPRINT system provides inadequate analgesia. 
 
Randomization.  Within the recovery room, the surgeon often performs a standard neurologic 
examination (variable depending on the surgeon and surgical procedure), after which time the 
subject will have baseline end points measured, including a pain score at the surgical site using 
the Numeric Rating Scale (NRS, 0-10), pain score (NRS) within the target nerve distribution, and 

sensory deficits (measured with alcohol pads and von Frey filament, compared to the 
contralateral limb within the cutaneous distribution of the target nerve).  For their first pulse 
generator—“Stimulator A”—subjects will be randomized to one of two treatments—current or 
sham—using computer generated lists and opaque, sealed envelopes.  The stimulator will then 
be attached to the lead and switched “on” (sham stimulator produces no current).  The end 
points will be measured per the table below.  Subsequently, the stimulator will be replaced by 
the alternative (current or sham)—“Stimulator B”.  The subject will have the end points 
measured and the stimulator replaced with a unit set to deliver active current for the 
remainder of study participation (“Stimulator C”).  Operating and recovery room pharmacologic 
analgesic requirements will be recorded.  Of note, if a lead fails to provide paresthesias within 
the target nerve distribution with either Stimulator A or B (adjustment of stimulator settings 
allowed), the lead may be replaced at the discretion of the subject and investigators. 
 
Of note, the data derived from the chronic pain literature suggests that there is a “carry over” 
effect following stimulation:  analgesia is provided even after the cessation of electrical current.  
It remains unknown if this is true following surgery in the acute postoperative pain period.  For 
subjects randomized to active current from Stimulator A, the data collected for Stimulator B 
placebo treatment may be lowered due to the carry over effect.  Therefore, this data will not be 
compared with the baseline or Stimulator A outcome measures.  However, it is valuable data to 
possibly detect and quantify the carry-over effect of the initial stimulation. 
 
At any time, subjects may choose to have their perineural catheter bolused with local 
anesthetic and a perineural local anesthetic infusion begun (if they desired a catheter with 
subsequent insertion).  Therefore, subjects will not risk receiving inferior analgesia by 
participating in this study.  However, subjects also have the option of leaving their infusion 
pump off and using neuromodulation as their primary analgesic if the latter proves adequate—
the decision is completely each subject’s and may be made any time prior to perineural 
catheter removal. 
 
Subjects and their caretakers will be trained in device care and management, and given written 
instructions as well.  Pain scores (resting and dynamic worst and average) will be collected daily 
for two weeks, along with oral analgesic requirements, perineural local anesthetic use, and 
sensory/motor deficits (all specific to the previous 24 hours).  Perineural catheters will be 
removed at home upon subject request, after 3 days, or upon local anesthetic reservoir 
exhaustion, whichever comes first (standard-of-care).  The electrical leads will be removed 
upon subject request, or after 30 days, whichever comes first.  The leads will be removed at 
home by subjects or their caretakers (standard-of-care for perineural catheter withdrawal) or 
by investigators, depending on both investigator and subject preference.  If removed by 
subjects or their caretakers, a picture of the extracted lead tip must be texted/emailed to 
investigators, or the physical lead returned to investigators for inspection.  Subjects will be 
contacted no less than every 5 days following the initial 2-week period until their lead is 
removed; and, will then be contacted 1 and 3 months postoperatively and the end points again 
verbally collected. 
 

Sample Size Estimation and Statistical Analysis Plan.  This is a feasibility study to demonstrate 
proof-of-concept and generate data to help design and power subsequent definitive, 
randomized, controlled clinical trials.  Therefore, a convenience sample of 40 subjects will be 
enrolled (10 additional subjects permitted to account for any drop-outs for a total of 50 
subjects).  Although this is a feasibility—and not definitive—investigation, we will treat as the 
primary end point the difference between the baseline pain score and pain score 5 minutes 
after the active (non-sham) electrical stimulator is first turned on.