If there is any question about wound infection when converting a first stage procedure to a full implant, it is prudent to have a low threshold for removing the lead and waiting for it to heal fully before proceeding with a full implant at a later date. If there is an obvious acute infection, or persistent or recurrent draining sinus weeks or months after implant, the entire implanted system should be removed. Usually the lead extracts very easily from the pocket due to surrounding inflammation, and a separate pre-sacral incision can be avoided. I have never seen a subsequent problem arising from the lead site using this strategy, though I suppose it could happen. I have been asked many times if both components must be removed, or if a salvage procedure may be tried such as with penile prosthesis. I do not know for sure, but it seems both of these strategies are likely to fail. It is not that hard to replace a lead, and the potential benefit of leaving it in place does not seem like it would outweigh the obvious risk. It is also my practice to excise any pseudo capsule to speed up formation of granulation tissue. I do not attempt to close the wound, but allow to heal by secondary intention, and to encourage the use of a wound vacuum system whenever feasible. I generally wait for a minimum of 3 months before considering reimplant when indicated.

The best possible surgical technique is unlikely to make a difference in efficacy if the procedure is performed on a poor candidate. My suggestion is to stick with FDA-approved indications, and make sure diaries are used to demonstrate sufficient objective benefit in the relevant symptom categories. The change in symptoms should be obvious and dramatic, and patients should never be pushed into a full implant. Even adhering to these suggestions, there may be a hierarchy in terms of which patients are likely to do best and require the least amount of reprogramming or revisions. It appears that the therapy is most robust for the fecal incontinence indication. I base this statement on the experience of colorectal surgeons in the USA, who are, as a group, the newest to the therapy and the least experienced, yet their success rate approaches 90% [3], and also on some examples of lead placements I have seen which were adequate for FI control but not for urinary complaints (Fig. 28.3). After FI, OAB wet is the most robust indication, while OAB dry and OAB with pelvic pain are successively harder indications requiring the most precision in lead placement. NOUR is in its own separate category due to the difficulty in identifying an ideal candidate. It seems the more “motor” the problem is, the easier it is to achieve success with less rigorous technique, and the more “sensory” the disorder, the more critical lead placement is, even perhaps to the point of needing alternate nerve targets (pudendal) and requiring electrodiagnosis (EMG) to place the lead next to the nerve. While still unproven, I think “optimal lead placement and response pattern” (Figs. 28.4 and 28.5) is necessary to achieve the best clinical result, especially in the more challenging conditions [4]. If precision is not used, it is more likely that the potential role for pudendal lead placement, bilateral stimulation, or an alternative therapy such as intravesical botulinum toxin will be falsely elevated.

Lead migration can also be an explanation for declining efficacy (Fig. 28.6a, b). I attempt to place a curve in the tunnel between the lead insertion site and the connection site when doing a staged procedure, in order to provide some “slack” which may prevent outward migration from pulling on the lead from pressure on the IPG or buttocks for normal movement. Inward migration is more of a problem overall, in part related to tine design, which resists only outward extraction. The most common scenarios for inward migration is in thin patients, where a “knuckle” occurs at the pre-sacral site (Fig. 28.7a–c). In addition to the presence of a knuckle being undesirable from a patient comfort standpoint, it can also lead to inward migration of the lead when the knuckle is pressed against a hard surface, such as a chair, before the lead has fully healed into place. Care must be taken to make a large enough incision to place a Sen inside the incision, and lift up on the Sen while tracking back towards the insertion site and deeply over to the IPG .