Sacral Neuromodulation
Table of contents
Recommended Reading
Operative Note
_ indicates a section that needs to be reviewed or completed.
I (or a fellow) will do the operative notes for procedures that I perform (and you assist). These notes are included here so that you can read about the procedure before we get to the OR - allowing you to familiarize yourself with both the steps of the procedure and nuances/dogma of my technique compared to another surgeon’s that you may have seen in the past. As you read the note, consider the instruments and anatomy. Consider how we maximize exposure and where the high risk portions of the procedure lie. Bonus points if you can customize the risk to the patients and their anatomy/history.
Stage One
After surgical consent was reviewed with the patient, including risks, benefits and alternatives, the patient expressed desire to proceed with surgery. She was placed in the sitting position and the location for INS placement was identified and marked bilaterally by measuring approximately 4cm below the posterior Iliac crest such that the neurostimulator would sit in the hollow if the ilium. The patient was asked to reach around with their hand to ensure this was a comfortable location to place the charging puck.
The patient was then taken to the operating room and placed in the prone position. Pillows were placed in the lower abdomen and hips to level and flatten the sacrum and allow the toes to dangle freely. Intravenous antibiotics were infused for infection prophylaxis. A ground pad was placed on the bottom of the patient’s foot and was connected to the Clinician Programmer along with the test stimulation cable (J-hook).
The patient was then prepped and draped in the usual fashion. _MAC anesthesia was induced.
Preoperative fluoroscopy was performed to visualize the sacral anatomy. Attention was turned to placement of the lead wire using the Axonics system. The level of S3 and the medial border of the sacral foramen were identified bilaterally using fluoroscopy in the AP view. After administration of local anesthesia, a foramen needle was placed in the superior, medial aspect ofthe S3 foramen such that the needle was parallel to medial border of the foramen. A lateral fluoroscopic image was then obtained to ensure the needle entry point was approximately 1 cm above and parallel to the fusion plate of S3. The needle was advanced such that the tip of the foramen needle was just at the anterior aspect of the sacrum.
The J-hook was then placed on the uninsulated portion of the foramen needle and stimulation applied to obtain the opening threshold amplitude. There was noted to be a positive bellows response at _mA and great toe flexion at _mA.
Once the ideal location was confirmed, a small incision was made at the foramen needle to accommodate the lead wire and tunneling tool. The directional guide was placed through the foramen needle and the needle removed. The introducer was placed over the directional guide and advanced under live fluoroscopy such that the radiopaque marker was placed half-way through the sacral plate. The dilator was removed along with the directional guide. Using live fluoroscopy, the tined lead with the curved stylet was placed through the introducer until electrode three straddled the anterior surface of the sacrum and ensuring the lead had a gentle downward trajectory. The stimulation clip was then placed on the distal lead and each electrode was tested observing for a motor response.
After satisfactory lead positioning was confirmed, the introducer was retracted over the lead under continuous fluoroscopy, deploying the tines into presacral tissue. Stimulation thresholds were established using the least amount of stimulation required to obtain a motor response.
A tunneling tool with an overlying plastic sheath was inserted from the lead insertion site subcutaneously to the location of the INS pocket site which had been previously marked to be located in the hollow of the ileum. After administration of local anesthetic, a 2.5cm incision was made lateral to the site of INS placement site, to a depth no greater than 2cm deep to the skin. A small pocket was created to accommodate the lead and percutaneous extension using combination of sharp and blunt dissection, maintaining the depth of 2 cm. The tunneling tool was passed from the lead wire insertion site to the lateral pocket. The sharp tip of the tunneling tool was removed and the lead was fed through the sheath, exiting at the pocket site. The sheath was removed. The lead was cleaned and dried and connected to the Axonics percutaneous extension with a single set screw which was tightened using the torque wrench. The percutaneous extension was tunneled to the contralateral side and exited through a skin puncture site that had been previously anesthetized. The percutaneous extension was then connected to the external pulse generator (EPG). The incisions were copiously irrigated with sterile water and the INS incision was closed with 2-0 Vicryl for the subcutaneous layer, skin was closed with running 4-0 Monocryl skin sutures. Gauze was placed over the incision and covered with transparent dressing.
Instrument, sponge, and needle counts were correct.
Stage Two
Rechargeable
After surgical consent was reviewed with the patient, including risks, benefits and alternatives, the patient expressed desire to proceed with surgery. The patient was then taken to the operating room and placed in the prone position. Pillows were placed in the lower abdomen and hips to level and flatten the sacrum and allow the toes to dangle freely. Intravenous antibiotics were infused for infection prophylaxis. MAC anesthesia was induced.
Attention was turned to placement of the neurostimulator. The prior incision was identified and local anesthesia administered. A 2.5 cm incision was made over the prior incision and the connection of the lead wire to the percutaneous extension was identified and exteriorized through the incision. The torque wrench was used to disconnect the percutaneous extension from the lead wire. The percutaneous extension connector was cut off and the wire was removed by pulling from the exit point. The INS pocket was created using combination of sharp and blunt dissection, maintaining the depth of 2 cm. The lead wire was connected to the neurostimulator and secured with the torque wrench. The neurostimulator was placed into the pocket with ceramic window placed laterally and the lead connection placed superiorly. Any excessive lead was coiled and placed behind the neurostimulator. Impedances were confirmed to be within normal limits.
The incisions were irrigated with sterile water and the INS incision was closed with 2-0 Vicryl for the subcutaneous layer, skin was closed with 4-0 Monocryl skin sutures followed by skin glue.
Instrument, sponge, and needle counts were correct.
Non-Rechargeable
After surgical consent was reviewed with the patient, including risks, benefits and alternatives, the patient expressed desire to proceed with surgery. The patient was then taken to the operating room and placed in the prone position. Pillows were placed in the lower abdomen and hips to level and flatten the sacrum and allow the toes to dangle freely. Intravenous antibiotics were infused for infection prophylaxis. MAC anesthesia was induced.
Attention was turned to placement of the neurostimulator. The prior incision was identified, and local anesthesia administered. A 2.5 cm incision was made over the prior incision, and the incision was extended medially up to 4 cm. The connection of the lead wire to the percutaneous extension was identified and exteriorized through the incision. The torque wrench was used to disconnect the percutaneous extension from the lead wire. The percutaneous extension connector was cut off and the wire was removed by pulling from the exit point. The INS pocket was created such that 1/3 of the INS was above the incision and 2/3 below so that the incisions would be over the flat portion of the INS. This was accomplished using combination of sharp and blunt dissection, maintaining the depth of 2-3 cm. The lead wire was connected to the neurostimulator and secured with the torque wrench. The neurostimulator was placed into the pocket with the lead connection placed superiorly and laterally. Any excessive lead was coiled and placed behind the neurostimulator. Impedances were confirmed to be within normal limits.
The pocket was irrigated with sterile water and the INS incision was closed with 2-0 Vicryl for the subcutaneous layer, skin was closed with 4-0 Monocryl skin sutures followed by skin glue.
Instrument, sponge, and needle counts were correct.
Full Implant
Postoperative Considerations
| Follow Up | 6 Weeks |
| Voiding Requirements | NONE |
| Opioids | AS NEEDED: Oxycodone 5mg PO Q6H #6 after Stage 1 or Full Implant |
| Pain Control | Alternate 1g acetaminophen and 600mg ibuprofen Q6H PRN |
| Precautions | Wound Infection |
| Restrictions | No showers/baths between stage 1 and stage 2, No deep waist bending/squatting for 6 weeks |
Patient Education
Preop
Postop
Implants & Devices
- Axonics R15 Rechargeable SNM System
- Axonics F15 Recharge-Free SNM System
- Medtronic Interstim X System
- Medtronic Interstim Micro System