Results of sacral neuromodulation therapy for urinary voiding dysfunction: outcomes of a prospective, worldwide clinical study

PURPOSE: This 5-year, prospective, multicenter trial evaluated the long-term safety and efficacy of sacral neuromodulation in patients with refractory urge incontinence, urgency frequency and retention. MATERIALS AND METHODS: A total of 17 centers worldwide enrolled 163 patients (87% female). Following test stimulation 11 patients declined implantation and 152 underwent implantation using InterStim. Of those treated with implantation 96 (63.2%) had urge incontinence, 25 (16.4%) had urgency frequency and 31 (20.4%) had retention. Voiding diaries were collected annually for 5 years. Clinical success was defined as 50% or greater improvement from baseline in primary voiding diary variable(s). RESULTS: Data for all implanted cases were reported. For patients with urge incontinence mean leaking episodes per day decreased from 9.6 +/- 6.0 to 3.9 +/- 4.0 at 5 years. For patients with urgency frequency mean voids per day decreased from 19.3 +/- 7.0 to 14.8 +/- 7.6, and mean volume voided per void increased from 92.3 +/- 52.8 to 165.2 +/- 147.7 ml. For patients with retention the mean volume per catheterization decreased from 379.9 +/- 183.8 to 109.2 +/- 184.3 ml, and the mean number of catheterizations decreased from 5.3 +/- 2.8 to 1.9 +/- 2.8. All changes were statistically significant (p <0.001). No life threatening or irreversible adverse events occurred. In 102 patients 279 device or therapy related adverse events were observed. At 5 years after implantation 68% of patients with urge incontinence, 56% with urgency frequency and 71% with retention had successful outcomes. CONCLUSIONS: This long-term study demonstrates that InterStim therapy is safe and effective for restoring voiding in appropriately selected cases refractory to other forms of treatment.     

Efficacy of sacral nerve stimulation for urinary retention: results 18 months after implantation

PURPOSE: We investigate the efficacy of sacral neurostimulation in patients with idiopathic urinary retention in a prospective, randomized multicenter trial. MATERIALS AND METHODS: A total of 177 patients with urinary retention refractory to standard therapy were enrolled in the study. Greater than 50% improvement in baseline voiding symptoms during a 3 to 7-day percutaneous test stimulation qualified a patient for surgical implantation of an InterStim parallel system. Of the patients who qualified for implantation 37 were randomly assigned to a treatment and 31 to a control group. Patients in the treatment group underwent early surgical implantation of the sacral nerve stimulation system, while implantation was delayed in the control group for 6 months. Followup evaluations, including voiding diary analysis and temporary deactivation of the stimulator at 6 months, were conducted at 1, 3, 6, 12 and 18 months after implantation in the treatment group, and after 3 and 6 months in the control group. RESULTS: Compared to the control group, patients implanted with the InterStim system had statistically and clinically significant reductions in the catheter volume per catheterization (p <0.0001). Of the patients treated with implants 69% eliminated catheterization at 6 months and an additional 14% had a 50% or greater reduction in catheter volume per catheterization. Therefore, successful results were achieved in 83% of the implant group with retention compared to 9% of the control group at 6 months. Temporary inactivation of sacral nerve stimulation therapy resulted in a significant increase in residual volumes (p <0.0001) but effectiveness of sacral nerve stimulation was sustained through 18 months after implant. CONCLUSIONS: Results of this prospective, randomized clinical study demonstrate that sacral nerve stimulation is effective for restoring voiding in patients with retention who are refractory to other forms of treatment.     

骶神经刺激治疗膀胱排尿功能障碍

目的：观察骶神经刺激治疗膀胱排尿功能障碍的疗效。方法：采用经皮穿刺刺激骶3神经治疗4例排尿功能障碍患者,其中1例接受永久性神经刺激器植入治疗。通过排尿日记及患者症状评价疗效。结果：3例难治性尿频尿急综合征的患者症状有显著改善,且排尿次数显著减少,平均排尿量增加,尿急程度减轻;另1例膀胱收缩无力患者无效。结论：骶神经刺激可以显著地改善部分患者膀胱排尿功能障碍。     

Sacral nerve stimulation for treatment of refractory urinary urge incontinence. Sacral Nerve Stimulation Study Group.

PURPOSE: A prospective, randomized study was performed to evaluate sacral nerve stimulation for the treatment of refractory urinary urge incontinence. MATERIALS AND METHODS: Primary outcome variables were obtained from voiding diaries. After baseline evaluation candidates who satisfied inclusion criteria were enrolled into the study. Test stimulation results determined eligibility for randomization into a stimulation (treatment) or delay (control) group. The stimulation group included 34 patients who underwent implantation and were followed for 6 months. The delay group comprised 42 patients who received standard medical therapy for 6 months and then were offered implantation. The stimulation group completed a therapy evaluation test (on versus off) after 6 months. RESULTS: At 6 months the number of daily incontinence episodes, severity of episodes and absorbent pads or diapers replaced daily due to incontinence were significantly reduced in the stimulation compared to the delay group (all p<0.0001). Of the 34 stimulation group patients 16 (47%) were completely dry and an additional 10 (29%) demonstrated a greater than 50% reduction in incontinence episodes 6 months after implantation. Efficacy appeared to be sustained for 18 months. During the therapy evaluation test the group returned to baseline levels of incontinence when stimulation was inactivated. Urodynamic testing confirmed that sacral nerve stimulation did not adversely affect voiding function. Complications included implantable pulse generator site pain in 15.9% of the patients, implant site pain in 19.1% and lead migration in 7.0%. Surgical revision was required in 32.5% of patients with implants to resolve a complication. There were no reports of permanent injury or nerve damage. CONCLUSIONS: Sacral nerve stimulation is safe and effective in treating refractory urinary urge incontinence.     

Sakrale Neuromodulation in der Urologie

Sacral nerve modulation (SNM) is an innovative, minimally invasive treatment that uses chronic low-level electrical stimulation of the sacral plexus to recruit residual physiological function of urinary bladder detrusor, pelvic floor muscles, and the anorectal continence structures. Classic indications for sacral neuromodulation in urology are refractory overactive bladder symptoms (urinary urgency ± incontinence) and chronic nonobstructive urinary retention. SNM also offers a therapeutic alternative in refractory chronic pelvic pain syndrome. The exact mechanism of action is still unknown, but it is assumed that electrical stimulation of the sacral nerves leads to neuromodulation as well as clinically beneficial effects in the pelvic floor, the sphincter complex, and the distal colorectum. SNM is a multistep procedure. In a test phase of so-called percutaneous or peripheral nerve evaluation (PNE), the effect of sacral neuromodulation is evaluated over days or weeks during which a bladder diary/pain protocol is kept. The predictive value of PNE is high, while morbidity and surgical trauma are low. The screening phase provided by PNE makes this technique unique and offers an ideal instrument for patient selection. After final implantation of the neurostimulator (InterStim II), the long-term success rate is over 60–90%. At our clinic, 42 patients underwent a PNE procedure between January 2009 and June 2010. Of these, 34 patients had a >50% success rate and had been implanted with the InterStim II device (80.9%). The success rates were 83% for overactive bladder and 89% for chronic retention (mean follow-up 7.8 months). In addition to the surgical procedure, the exact indication and postoperative care are important prerequisites of successful therapy. To date, no information on the number of implanted stimulators in Germany is available. This suggests the need for establishment of a national prospective registry. It would also be appropriate that the experts from the implantation centers form a working group.     

Neurostimulation for lower urinary tract voiding problems

In 1981, Tanagho and Schmidt introduced chronic electrical stimulation of the sacral spinal nerves using a permanently implanted sacral foramen electrode and a battery-powered pulse generator for treatment of different kinds of lower urinary tract dysfunction, refractory to conservative treatment. At our department, chronic unilateral electrical stimulation of the S3 sacral spinal nerve has been used for treatment of vesicourethral dysfunction in 55 patients with a mean postoperative follow-up of 44.3 months. Lasting symptomatic improvement of more than 50% was achieved in 16 of 21 patients with motor urge incontinence (76.2%) and in 22 of the 28 patients with urinary retention (78.6%). In our opinion, chronic sacral neuromodulation offers a sustained therapeutic effect to treatment responders that is not achieved by temporary neuromodulation techniques. Chronic neuromodulation should be considered predominantly in patients with urinary retention and in patients with motor urge incontinence who refuse temporary techniques or who require too much effort to achieve a sustained clinical effect.     

Predictors of success for first stage neuromodulation: motor versus sensory response

PURPOSE: We investigated whether intraoperative motor or sensory response is more predictive of successful sacral neuromodulation using the InterStim system. MATERIALS AND METHODS: A total of 35 patients with medically refractory frequency, urgency and urge incontinence were enrolled in the study. All patients underwent lead placement for quadripolar test stimulation under local anesthesia with intravenous sedation. Confirmation of correct lead placement was by observation of known motor and sensory responses that result from third sacral nerve stimulation. Motor and sensory responses were documented intraoperatively. Patients had a 1-week trial of stimulation, and those who had greater than 50% improvement in symptoms had placement of the implantable pulse generator. Those without at least 50% improvement in their symptoms had the quadripolar lead removed. RESULTS: Of the 35 patients enrolled 21 had successful quadripolar test stimulation and went on to permanent implantable pulse generator placement. Of the patients who had successful quadripolar test stimulation 95% demonstrated positive intraoperative motor response whereas only 21.4% of patients with unsuccessful quadripolar test stimulation demonstrated positive motor response. If only a positive sensory response was elicited, patients had only a 4.7% chance of having a positive quadripolar test stimulation. CONCLUSIONS: A positive quadripolar test stimulation (greater than 50% improvement in symptoms) with InterStim sacral neuromodulation is more likely when intraoperative lead placement results in positive motor response vs only sensory response.     

Sacral nerve neuromodulation in the treatment of patients with refractory motor urge incontinence: long-term results of a prospective longitudinal study

PURPOSE: Conservative treatment rarely results in a durable cure of patients with urge incontinence and bladder overactivity. Instrumental and surgical procedures often have significant side effects and less than optimal results. We developed a technique of sacral nerve neuromodulation using chronic unilateral electrical stimulation of the S3 sacral nerve to inhibit the micturition reflex to provide effective nondestructive alternative therapy for patients whose condition is refractory to conservative treatment. MATERIALS AND METHODS: Of 85 patients 45 who responded to a test with a temporary electrode underwent implantation of a permanent S3 sacral nerve electrode coupled to a pulse generator. Treatment results were evaluated by urodynamic studies and voiding/incontinence diaries documenting pad use, incontinence episodes, voiding frequency and voided volume. Partial success and cure were defined as 50% to 90% and more than 90% improvement, respectively, in pad use and/or incontinence episodes. RESULTS: Of 45 patients 18 (40%) were cured at an average followup of 47.1 months and 9 (20%) achieved partial success. Median number of pads used and median number of incontinence episodes daily had decreased from 5.4 to 1.2 (p = 0.0001) and 7.1 to 1.3 (p = 0.0001), respectively, 6 months after implantation. Subsequently these results remained almost constant for 5 years. Bladder overactivity disappeared in 19 of the 44 patients (43%). The repeat intervention rate was 37.7% and there was no permanent injury or nerve damage. CONCLUSIONS: Sacral nerve neuromodulation is safe, effective and durable in patients with urge incontinence refractory to conservative treatment.     

Implantable neuromodulation for urinary urge incontinence and fecal incontinence: a urogynecology perspective

Implantable sacral nerve stimulation is a minimally invasive, durable, and reversible procedure for patients with urinary urge and fecal incontinence who are refractory to conservative therapy. The therapy is safe compared with other surgical options. An intact external or internal rectal sphincter is not a prerequisite for success in patients with fecal incontinence.     

Sacral neuromodulation in the treatment of urgency-frequency symptoms: a multicenter study on efficacy and safety

PURPOSE: Neuromodulation of sacral nerves has shown promising results in correcting voiding dysfunction. We report the results of a multicenter trial designed to assess the efficacy of sacral nerve neuromodulation in patients presenting with refractory urinary urgency-frequency. MATERIALS AND METHODS: A total of 51 patients from 12 centers underwent baseline assessment, including a detailed voiding diary, urodynamic evaluation and percutaneous test stimulation of the sacral nerves at S3 and/or S4. All patients enrolled in the study had undergone prior conventional treatment, such as pharmacotherapy, hydrodistention and surgical intervention, which failed. All patients demonstrated a satisfactory response to trial stimulation and were randomly divided into a stimulation group (25 patients) and a control group (26). A sacral nerve stimulation device was implanted after 6 months in the control group. Patients were followed at 1, 3 and 6 months, and at 6-month intervals for up to 2 years after implantation of a neuroprosthetic InterStim* system. dagger The study variables included the number of voids daily, volume voided per void and degree of urgency before void. RESULTS: Compared to the control group, 6-month voiding diary results demonstrated statistically significant improvements (p <0.0001) in the stimulation group with respect to the number voids daily (16.9 +/- 9.7 to 9.3 +/- 5.1), volume per void (118 +/- 74 to 226 +/- 124 ml.) and degree of urgency (rank 2.2 +/- 0.6 to 1.6 +/- 0.9). Patients in the control group showed no significant changes in voiding parameters at 6 months. Significant improvements in favor of the stimulation group were noted in various parameters with respect to water cystometry and quality of life (SF-36). At 6 months after implant, neurostimulators were turned off in the stimulation group and urinary symptoms returned to baseline values. After reactivation of stimulation sustained efficacy was documented at 12 and 24 months. CONCLUSIONS: Neuromodulation of the sacral nerves is an effective, safe therapy that successfully treats significant symptoms of refractory urgency-frequency.     

First Scandinavian experience of electrical sacral nerve stimulation in the treatment of the overactive bladder

OBJECTIVE: This study aimed to evaluate the efficacy of electrical sacral nerve stimulation (SNS) in the treatment of urinary incontinence and urinary retention refractory to conservative treatment, and to assess the impact of urodynamic abnormalities and electrode position. MATERIAL AND METHODS: Thirty patients (10 men, 20 women) with a mean age of 59 years (range 21-79 years), all of whom had longstanding symptoms ranging from 2 to 46 years (mean 12.4 years), were subjected to a percutaneous test stimulation. Ten patients responded well, resulting in a permanent implant in nine patients. Electrode positions were determined by plain X-ray and computed tomography. RESULTS: Radiologically, a variety of positions of the temporary electrodes was seen. In the implanted patients, long-term symptom reduction varied over time, ranging from total relief to partial or total recurrence of symptoms. CONCLUSIONS: SNS is a new promising option for the treatment of urge incontinence. Refined instruments for proper patient selection and the optimal way to position the electrode remain to be developed.     

The role of neuromodulation in the management of urinary urge incontinence

OBJECTIVE: To examine the benefit-risk profile of neuromodulation in treating refractory urinary urge incontinence and other voiding disorders. PATIENTS AND METHODS: The outcome measures from all patients in pivotal clinical trials who had undergone sacral nerve stimulation were analysed retrospectively. RESULTS: Neuromodulation was effective in several clinical studies; the response is durable and the benefit-risk profile good. CONCLUSION: Sacral nerve stimulation is becoming the standard of care for refractory overactive bladder and retention problems. The potential benefit of neuromodulation should be included in female urology and gynaecology training programmes.     

Sacral neuromodulation decreases narcotic requirements in refractory interstitial cystitis

OBJECTIVE: To assess the efficacy of long-term sacral neuromodulation (InterStim(R), Medtronic Inc., Minneapolis, MN) in treating chronic pelvic pain associated with interstitial cystitis (IC, a symptom complex of urinary urgency, frequency and pelvic pain, often necessitating narcotics) refractory to standard therapy. PATIENTS AND METHODS: Twenty-one patients (17 female, four male, mean age 45.5 years, range 17-68) with refractory IC with chronic pelvic pain were reviewed retrospectively. In these patients a mean of six previous treatments for IC had failed. All patients had had cystoscopy and hydrodistension to confirm their diagnoses. All had a permanent InterStim device implanted by one surgeon (K.M.P.) between 2000 and 2002, after responding to a temporary test. Data were collected from chart reviews and patient questionnaires. Intramuscular morphine dose equivalents (MDEs) were calculated before and after implantation. RESULTS: All 21 patients responded to the questionnaire; the mean (range) follow-up after implantation was 15.4 (7.4-23.1) months. Eighteen patients used chronic narcotics before the InterStim and 20 reported moderate or marked improvement in pain afterward. The mean MDE decreased from 81.6 to 52.0 mg/day (36%) after implantation (P = 0.015). Four of 18 patients stopped all narcotics after InterStim implantation. CONCLUSIONS: Sacral neuromodulation decreases narcotic requirements and subjective pelvic pain in patients with refractory IC. Further decreases in MDE are anticipated as dose reductions continue in patients who improved.     

How Does Sacral Modulation Work Best? Placement and Programming Techniques to Maximize Efficacy

Since receiving approval from the US Food and Drug Administration in 1997, sacral neuromodulation (SNM) has become the recommended treatment of urinary urge incontinence, urgency–frequency, nonobstructive urinary retention, and fecal incontinence. The manufacturer has introduced different technical modifications while surgeons and researchers have adapted and published various innovations and alterations of the technique. This review summarizes the current knowledge and recommendations of SNM preoperative decision making, the implantation technique, and available programming parameters and algorithms based on MEDLINE research, manufacturer instructions, and the approach of an experienced neurourological team. The primary steps and technical aspects to optimize SNM efficacy were the introduction of the tined-lead electrode and the development of the InterStim II impulse generator (both developed by Medtronic, Inc., Minneapolis, MN). The initiation of the staged implantation technique for sequential evaluation and implantation with the definitive quadripolar electrode completes the treatment algorithm so that an increased responder rate of SNM for all indications can be achieved.     

Implant infection after two-stage sacral nerve stimulator placement

To report our experience with implant infection after two-stage sacral nerve stimulator placement. We reviewed the records of all patients who underwent implantation with a sacral nerve stimulator for the management of refractory cases of urge urinary incontinence, urinary frequency, and non-obstructive urinary retention. Baseline demographic data, interval to the development of infection, and the organism cultured are reported. After stage II neurostimulator placement, 5 out of 37 (13.5%) women required device removal for culture positive wound infections. Patients returned an average of 147.4 days after device implantation with evidence of infection. Infection occurred a minimum of 33 days, a median of 76 days, and a maximum of 461 days after sacral nerve stimulator implantation. The most common pathogen cultured was Staphylococcus aureus. After device removal, all patients resolved their infections. Two patients underwent uncomplicated reimplantation in the contralateral buttock 14 and 16 days after stimulator removal. The risk of infection after tined lead pretest and neurostimulator placement may be higher than previously observed in older techniques. Funding: This study did not receive independent funding.     

Neurosurgical treatment of hyperactive bladder in spinal cord injury patients

OBJECTIVES: We report long-term results of posterior sacral root rhizotomies in combination with Finetech-Brindley anterior sacral root stimulators implanted intradurally in 20 spinal cord injury patients. MATERIAL: and methods: The 14 female and 6 male patients included 14 paraplegics and 6 tetraplegics. All of them initially presented hyperactive bladder, detrusor-sphincter dyssynergia, recurrent urinary tract infection and performed (self) intermittent catheterization. Prior to implantation, an intrathecal test using bupivacaine was performed to confirm the compliances of the bladder. The main indication for implantation was persistent urinary incontinence refractory to medical therapy. RESULTS: After implantation the mean follow-up was 4,5 years. In all, 18 patients used the stimulator alone for bladder emptying and 18 patients were completely continent. The mean bladder capacity increased from 190 ml preoperatively to 460 ml after the operation. The mean residual urinary volume was reduced from 90 ml to 25 ml. No changes were noted by renal isotopic scanning in upper urinary tracts of patients. In 1 patient, a second extradural implant was performed. DISCUSSION: This article also include an overview of a) the different available sites where application of electrical stimulation results in a detrusor contraction, b) the benefits and disadvantages of the sacral posterior rhizotomy, c) selective stimulation techniques that allow selective detrusor activation by sacral root stimulation. CONCLUSION: Sacral anterior root stimulation combined with sacral posterior rhizotomy is a valuable method to restore bladder functions in spinal cord injured patients suffering from hyperactive bladder refractory to medical therapy.     

Different brain effects during chronic and acute sacral neuromodulation in urge incontinent patients with implanted neurostimulators

OBJECTIVE: To compare changes in regional cerebral blood flow (rCBF), using positron emission tomography (PET), during chronic and acute sacral neuromodulation (SN). SN is an effective long-term treatment for chronic urge incontinence due to urinary bladder hyperactivity, as sensory nerves, spinal and supraspinal structures are probably responsible for the action of SN. It is not known which brain areas are involved, and the optimum benefit of SN is not immediate, suggesting that induced plasticity of the brain is necessary. PATIENTS AND METHODS: Brain activity was measured in two groups: 12 urge incontinent patients (11 women and one man; mean age 52 years) in whom an implanted unilateral S3 nerve neurostimulator had been effective for >6 months (mean time after implantation 4.5 years); and eight urge incontinent patients (seven women and one man; mean age 49 years) in whom the neurostimulator was activated for the first time in the PET scanner. RESULTS: During SN in chronically implanted patients, there were significant decreases in rCBF in the middle part of the cingulate gyrus, the ventromedial orbitofrontal cortex, midbrain and adjacent midline thalamus, and rCBF increases in the dorsolateral prefrontal cortex. During acute SN in newly implanted patients, there were significant decreases in rCBF the medial cerebellum, and increases in the right postcentral gyrus cortex, the right insular cortex and the ventromedial orbitofrontal cortex. Group analysis between chronic and newly implanted patients showed significant differences in the associative sensory cortex, premotor cortex and the cerebellum, all three involved in learning behaviour. CONCLUSIONS: These findings suggests that chronic SN influences, presumably via the spinal cord, brain areas previously implicated in detrusor hyperactivity, awareness of bladder filling, the urge to void and the timing of micturition. Furthermore, SN affects areas involved in alertness and awareness. Acute SN modulates predominantly areas involved in sensorimotor learning, which might become less active during the course of chronic SN.     

Preliminary results of sacral neuromodulation in 23 children

PURPOSE: Sacral nerve stimulation with InterStim is approved in the United States for use in adults. Limited data on the effectiveness of sacral nerve stimulation in children are available. We report our experience with patients who underwent InterStim placement for the treatment of severe dysfunctional elimination syndrome, which is defined as a constellation of functional urinary and gastrointestinal symptoms in patients without anatomical anomalies or obvious neurological disease, in whom intensive medical and behavioral therapies have failed to improve symptoms. MATERIALS AND METHODS: A total of 23 patients 6 to 15 years old with presenting symptoms of dysfunctional voiding, enuresis, incontinence, urinary tract infections, bladder pain, urinary retention, urgency, frequency, constipation and/or fecal soiling were followed for a mean of 13.3 months after InterStim placement. RESULTS: Of the 19 patients with urinary incontinence 3 (16%) had complete resolution, 13 (68%) had improvement, 2 (11%) were unchanged and 1 (5%) was worse (sign test, p = 0.002). Among the 16 patients with nocturnal enuresis 2 (13%) had resolution, 9 (56%) improved, 4 (25%) were unchanged and 1 (6%) was worse (sign test, p = 0.0063). Of the 15 patients with urinary retention requiring intervention 9 (60%) had improvement and 1 had worsening symptoms (sign test, p = 0.022), while 2 of 6 patients (33%) on intermittent catheterization were able to stop. One patient had development of new incontinence and enuresis. Bladder pain, urgency, frequency and constipation improved in 67% (8 of 12), 75% (12 of 16), 73% (11 of 15) and 80% (12 of 15) of the patients, respectively. Medications required postoperatively decreased by an average of 3 per patient (p < 0.001). The overall patient satisfaction rate was 64%, while that of the caregiver was 67%. Two leads were explanted from the 23 patients. Complications encountered included 1 seroma, 1 episode of skin sensitivity, 2 device failures and 1 lead revision. CONCLUSIONS: Sacral nerve stimulation in children is an option for carefully selected patients who have failed other therapies. Our results show that sacral nerve stimulation was effective in the majority of patients with the dysfunctional elimination syndrome. However, longer followup is needed.     

Failure of sacral nerve stimulation due to migration of tined lead

PURPOSE: Stimulation of the sacral nerves is a commonly used treatment for frequency, urgency, urge incontinence, retention and other types of voiding dysfunction. Minimally invasive placement of a percutaneous permanent quadripolar tined lead into the sacral foramen has been described. No lead migration has been reported. We report on our experience with lead migration and the subsequent failure of InterStim in a large cohort of patients with a focus on possible diagnostic and salvage techniques. MATERIALS AND METHODS: Between February 2002 and April 2005 tined lead electrodes were implanted in the S3 foramen in 235 patients using the InterStim system. Patients with a good response during the testing phase (greater than 50% improvement) underwent placement of an implantable pulse generator. Position was confirmed by radiographic evaluation intraoperatively. Sacral radiographs were obtained at the first postoperative visit, after IPG placement and whenever there was a change in symptomatic response. RESULTS: There were 5 patients (2.1%) in whom treatment failed after a successful trial of stimulation due to lead migration. This was seen as early as 3 weeks and as late as 8 months. Migration of the lead occurred between first and second stage implantation in 1 of the 5 cases, and occurred after the second stage in 4 of 5. Anterior migration was noted in 4 patients and posterior migration was noted in 1. CONCLUSIONS: Lead migration after placement of the tined lead can occur and thus sacral radiographs should be routinely used. This complication can be easily resolved without significant morbidity to the patient.