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InterStim Therapy is unique in that a test stimulation is performed to assess the effectiveness of the therapy prior to placing the Neurostimulator implant. Most often InterStim is performed as an outpatient procedure and is performed at the hospital under local anesthetic with sedation.  In some instances the doctor may choose to allow the patient to go to sleep during the procedure (general anesthesia).  The procedure consists of two small incisions in the skin.  A lead wire is placed just under the skin through a very small incision over the lateral aspect of the sacrum (tailbone).  A temporary lead extension is placed just under the skin through a second slightly larger incision over the upper buttock.  The temporary lead extension connects to an externalized wire that is plugged into a temporary stimulator that can be worn on the waistband either inside or outside of the clothing.  In some cases two test stimulations leads are placed under the skin.  This is called bilateral lead placement and is most often conduced to improve the patient’s outcome to the procedure.  The temporary stimulator is used for 2-4 weeks to assess the results of the stimulation.


Stage I – InterStim Therapy Instructions:

Please read and re-read the following instructions.  Following the instructions in this handout in detail is crucial to aid in your success with InterStim Therapy.        


Pre-Test Procedure Instructions:


  • Maintain a voiding diary for a minimum of 3 days (bring your diary with you to your test procedure).

  • No aspirin or other blood thinning medication should be taken for 7 days prior to your procedure.

  • Nothing to eat 8 hours before your procedure.

  • Arrive on time for your procedure.


Post Test Instructions:


Following the connection to the external test stimulator box, most patients will go home about 1-2 hours after the procedure or after you are feeling well enough to leave.  In some cases, if the patient has other health conditions, the patient may be kept overnight for observation.  Following the procedure a Medtronic therapy consultant or the nurse will connect the stimulator box and provide oral and written instructions for the start of the therapy.  The stimulator box is connected to a connection cable; the cable is connected to the implanted lead in your back.  There are four stimulation points (electrodes) on the lead.  If the initial electrode setting does not improve your symptoms, other electrode sites will be selected.  Adjustments of electrode sites will most often be performed over the telephone by a Medtronic Therapy Consultant or in your doctor’s office by the nurse. 


Post Test Procedure Instructions:


  • Maintain a new 2nd voiding diary.  Try not to alter your everyday activities during the trial period (i.e., fluid intake, caffeine, alcohol, and medications).  Continue your life as before the InterStim procedure.

  • Take antibiotics as prescribed.

  • Take prescribed medication for pain if needed.

  • Restrict activity for at least one week.  Your body needs time to rest. Being too active too soon can increase the likelihood of complications.

  • Showers may resume 72 hours after the procedure (no soaking).  Always unplug the test box and set aside prior to showering.  When taking your first few showers allow approximately 90% of the water to hit the front of your body. It is okay to turn in the shower to rinse off your back side, however, avoid prolonged water exposure on your backside when in the shower.

  • During the test stimulation period no baths, no swimming, no hot tubs, and no sits baths are allowed.

  • Continue using the wound dressing on your backside for at least 4 days and up to 7 days.  If the dressing becomes saturated with fluid or blood, change the dressing with a sterile 4 x 4 gauze dressing and use paper tape to hold the dressing in place.  When the dressings are completely dry for a 24-hour period, you may discontinue use of the dressings earlier than 7 days.  You will notice small strips of tape (Steri-Strips) underneath the dressing.  Do not remove the tape strip.  Your nurse will remove the tape at your follow-up visit.

  • Always turn off and unplug your test stimulator when operating a motor vehicle.

  • To prevent your stimulator from pulling on your incision, always unplug your test stimulator and set aside on a counter top prior to undressing or using the toilet.  (If you are diagnosed as a “Retention” patient, you should continue use of the stimulator when using the toilet to urinate.  Do not disconnect the stimulator, but be careful not to drop the stimulator when disrobing to use the bathroom).


Use of the Temporary Test Stimulator:


There is an on-off power dial/amplitude dial marked with the letter “A” (Amplitude).  This dial is used to activate the unit and control the intensity of the stimulation.  When the unit has been turned on using the “A” dial, a small green light next to the “A” dial flashes.  The green flashing light indicates the unit is functioning normally.


A flashing amber light next to “BAT” indicates the 9-volt battery is weak and needs to be replaced.  If no indicator light is visible when the stimulator box is turned on, try turning off the box for 10 seconds and turn back on.  If no light is visible, insert a new 9-volt battery into the lower compartment of the stimulator box. 


The “R” dial is the rate dial and has been preset for you.  Tape has been placed over the dial to hold the rate setting position.  Please do not change the “R” setting.  The test stimulator unit is small enough to be worn inside or outside of your clothing and is powered by an ordinary 9-volt battery.  The device also has a clip that can be used to hold the unit on the waistband. 


The stimulation should feel like a gentle pulsing, vibration or thumping sensation.  Although the lead is secured in place, it may move slightly as you change position.  Moving from sitting to standing may cause stimulation to stop, become more/less intense, and may even change locations of where you are feeling the stimulation.  You may need to adjust the intensity of the stimulation with the “A” dial accordingly to your comfort level when you change positions.  Approximately 4-6 weeks after the initial procedure, the lead will heal and secure better into position whereby adjustments to the stimulation become less frequent.


The amount and comfort of the stimulation is always 100% under your control.  You may turn the stimulation up and down, or on and off.  The stimulation should be comfortable.  More stimulation is not better; please avoid making the stimulation uncomfortable by having the stimulation too high.  The stimulation should be on (green light) and felt comfortably 24 hours a day.  If stimulation becomes painful, turn the stimulation down.  If the stimulation fades away, turn the stimulation up.


If you are unable to feel the stimulation:

  • Try increasing the amplitude.

  • Turn the test stimulator off, wait 10 seconds, and turn it on again, slowly increasing the amplitude.  Look for the green indicator light.

  • Change the 9-volt battery in the stimulator box (Energizer batteries are preferred).

  • Check the connections: lead in back to external cable; external cable to stimulator box.

  • If unable to restart stimulation, call the Medtronic Consultant or your doctor’s office.


Complications are rare, but may occur:

  • A small amount of blood or serous fluid (clear fluid) on the dressing is normal.  Incision pain is normal; rest and take your pain medication before the pain becomes too intense.

  • If you are experiencing pain as a result of the stimulation, even at a low setting, turn the stimulator box off for 2 hours.  After 2 hours, turn the box back on again and continue testing.  If after turning the stimulator off for 2 hours and the pain returns, turn off the stimulator box and contact the Medtronic Consultant via voice mail.  To reset your stimulator box.  (See “Important Follow-Up” section).

  • The chance of infection can occur anytime the skin is opened.  (Take all prescribed antibiotics).

  • Symptoms of infection are:  Fever over 101 degrees; foul smelling or yellow drainage at the incision site; pain, redness and swelling at the incision site.  An incision that is looking worse, not better as time goes by.



*Important Follow-Up*

Brad Anderson-Medtronic InterStim Therapy Consultant will be working with you to insure that your test stimulation is a success  Two days following your initial procedure contact Brad-Therapy Consultant by phone at: 1-800-638-7621; key in extension _________ followed by the “#” sign.  You will be prompted to leave a detailed message.  Please leave a message regarding your current status, as it relates to how InterStim Therapy is affecting your urinary symptoms.  Please leave your telephone number and area code on the voice mail.  Brad does not have your contact information and will not contact you unless you leave your return telephone number with your authorization for him to contact you by telephone.   When leaving your information on voice mail, please state the following:

  • Your name

  • Your doctor’s name

  • Your surgery date

  • Your area code and telephone number

  • Your percentage of improvement since the procedure

  • Any technical questions you may have regarding InterStim Therapy.


Please try to quantify the amount of improvement into a percentage of improvement (i.e., 20% improved, 75% improved, 100% improved).  This information will dictate how much follow-up will be necessary prior to the second stage of the procedure.


Brad will return your call Monday through Friday, most often the same business day that you place your call.  Please keep in mind that during the day Brad is in surgery and is most often unable to return calls. Most calls are returned in the early evening hours.  During your returned call, changes may be made to your test stimulator box.  Following the changes, Brad may have you call back in 2-3 days following the change to track your progress.  If you require additional information or have questions, you may call Medtronic Patient Services at: 1-800-510-6735.  In an emergency situation, Brad can be reached on his cell phone at 612-720-3533




After you have had the Stage One procedure you may notice symptom improvement during the first few days. However, many patients may not experience improvement that soon.  It is important to understand that adjustments to your stimulator box may be necessary to obtain symptomatic improvement.  Brad or the nurse may make changes to your stimulator box to help you see optimal results.  Many patients see improvement within the first week; others may take several weeks to see improvement.  Generally, patients with the diagnosis of “retention” may need additional time with the stimulator box to see results.  Please remember that this is a test phase and this time period will allow you to see just how this therapy can impact your life.  At the end of the test period, you will have the option of having the stimulator implanted or have the test wire removed.


Medical Questions:

If you have any questions regarding your incision, medication, return to work, activities of daily living, pain management or have other medical related questions please contact your doctor. Brad is unable to answer any medical questions and will have you contact the doctor.  Good luck with your trial!             


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