脊髓电刺激治疗复杂区域性疼痛综合征

目的探讨脊髓电刺激术（spinal cord stimulation,SCS）治疗复杂性区域性疼痛综合征（complex regional pain syndrome,CRPS）的有效性。方法回顾性分析4例CRPS病例,其均经脊髓电刺激手术治疗并随访1年以上,采用视觉模拟疼痛评分（VAS）评估疼痛转归。结果病人术后VAS评分平均降低5．4,3例病人疼痛缓解大于50％,无手术并发症。结论SCS能够安全、有效地治疗CRPS。、     

Spinal Cord Stimulation in Complex Regional Pain Syndrome Type I of Less Than 12‐Month Duration

Introduction: Complex regional pain syndrome type 1 (CRPS‐1) has a 31% probability of becoming chronic. The early use of spinal cord stimulation (SCS) has been recommended as a strategy to prevent chronicity and functional impairment. Methods: In a prospective study, we treated 74 CRPS‐1 patients with a mean disease duration of 17 weeks with standard therapy consisting of physical therapy, topical dimethyl sulfoxide, analgesics, transcutaneous stimulation, and sympathetic blockade. Patients who did not respond to standard therapy were offered a treatment with SCS. In these patients, we investigated the impact on pain, quality of life, and function. Results: Out of these 74 patients treated with standard therapy, six patients were included for early SCS treatment. The overall mean pain relief after one year was 35%. The mental component of the Short Form 36 improved; however, there was no effect on the physical component. None of the SCS treated patients showed a clear improvement in functional outcome. Discussion: We conclude that the feasibility of performing a randomized controlled trial on early SCS therapy in CRPS‐1 is low because of the good disease improvement with standard therapy in the first year after onset. This study raises questions about the need to use SCS early in the course of CRPS‐1 because of the probable lack of additional benefit compared with SCS in chronic CRPS‐1.     

Selective Nerve Root Stimulation (SNRS) in the Treatment of End‐Stage,Diabetic, Peripheral Neuropathy: A Case Report

Spinal cord stimulation (SCS) for the treatment of painful peripheral neuropathy (PN) has been met with mixed results. It has been suggested that early‐stage symptoms that are sympathetically maintained (SMP) are more likely to respond to SCS, while progressive sympathetically independent symptoms (SIP) will not. Peripheral nerve stimulation (PNS), however, has successfully treated certain SIP presentations. With the advent of new selective nerve root stimulation (SNRS) strategies, the possibility of utilizing epidural, peripheral neurostimulation was investigated in a patient with endstage, diabetic, “dying back” peripheral SIP.     

Thermogram in spinal cord stimulation with complex regional pain syndrome and a review of the literature

Introduction: Spinal cord stimulation (SCS) is an efficient procedure for treatment of intractable pain. Methods: We present a patient who underwent SCS lead placement for severe left lower extremity pain. The patient had experienced good pain. He underwent thermographic imaging before, just after and ten days later of procedure. Results: Thermogram study revealed from blue color (hypothermic) pattern at before procedure to reddish or pink color (hyperthermic) pattern at ten days later. Discussion: SCS may be increase microcirculation and seems to have sympatholytic effects. Conclusion: We experienced that improvement of blood flow as result of SCS in CRPS.     

Tripolar Spinal Cord Stimulation for the Treatment of Abdominal Pain Associated With Irritable Bowel Syndrome

Objectives: The objective of this case report is to describe the use of transverse tripolar dorsal column stimulation in a patient with a history of irritable bowel syndrome (IBS) associated with abdominal pain resistant to conservative treatments. Method: We report a 36‐year‐old man who presented to the pain clinic with an eight‐year history of IBS (constipation predominant with occasional diarrheal episodes), with “crampy and sharp” abdominal pain. He also had nonradicular thoracic spine pain due to thoracic scoliosis. Both pains were affecting his ability to function as an attorney. Prior conservative therapy, including psychologic treatment, antidepressants, and opioids, was without any benefits. Results: The use of a spinal cord stimulator (SCS) was discussed with the patient. The procedure was performed after Institutional Review Board approval. A tripolar SCS was implanted at the T8 level using one‐eight contact and two‐four contact percutaneous leads based on paresthesia reproduction of patient's areas of discomfort. This tripolar spinal cord stimulation provided relief of abdominal and thoracic pain, and better management of gastrointestinal symptoms. The patient was followed‐up for one year, and his quality of life also was improved via the IBS‐Severity Scoring System quality of life tool. Conclusions: The use of the tripolar SCS in this patient provided relief of abdominal and thoracic spine pain, regulated bowel habits, and improved the patient's quality of life. We believe that the use of SCS should be considered as a treatment option in patients with IBS when all conservative treatments failed.     

A New Technique of “Midline Anchoring” in Spinal Cord Stimulation Dramatically Reduces Lead Migration

Spinal cord stimulation (SCS) is a popular method of treatment of chronic pain. Unfortunately, migration of the lead continues to be a serious complication of this therapy. In an attempt to reduce lateral migration of the SCS lead, we performed a retrospective assessment of a new technique of percutaneous lead placement. This new method of “midline anchoring” of the lead using the plica mediana dorsalis was tested against conventional technique in a retrospective study involving 122 trials and 91 implants of SCS over a period of five years. The use of “midline anchoring” resulted in a decrease in lead migration from 23% to 6% after trial insertion and from 24% to 7% after implantation. We conclude that “midline anchoring” of the SCS lead is an effective method of preventing lead migration.     

Spinal cord stimulation for complex regional pain syndrome: report of 2 cases

Two adolescents with complex regional pain syndrome (CRPS) were treated safely and effectively by spinal cord stimulation (SCS). They complained of intractable pain resistant to conservative therapies. Whereas continuous epidural anesthesia temporarily reduced pain, SCS was more effective in alleviating chronic severe pain and improving the quality of life. With careful selection of patients, SCS therapy might be recommended even in young cases.     

Spinal Cord Stimulation,Conception, Pregnancy,and Labor: Case Study in a Complex Regional Pain Syndrome Patient

Introduction. Interventional modalities for pain treatment are reserved for patients failing multidisciplinary pain management, including psychological, physical, pharmacological, and anesthetic techniques. Objective. Medications for intractable pain may be unacceptable because the risk of teratogenic effects. The purpose of this study is to find out whether spinal cord stimulation may be safe during conception, pregnancy, and delivery. Materials and Methods. We report a 30-year old, female, neonatal nurse who developed left hand burning pain, swelling, coldness, and weakness following a mild brachial plexus injury in a motor vehicle accident. The patient responded well to a combination of Neurontin, Trazadone, Ultram, and Vicodin. A year later, the patient married and wanted to become pregnant but was afraid of possible teratogenic effects of the medications. Therefore, she requested an interventional modality for control of her symptoms. We recommended spinal cord stimulation (SCS) based on our excellent experience with this modality in the management of complex regional pain syndromes (CRPS). However, we did inform the patient that no data had been published regarding the safety of this modality in pregnancy and labor. Results. Cervical SCS resulted in excellent pain control and discontinuation of the medications. Thirteen months later, she delivered a healthy five pound baby girl. Mother and baby were discharged home in two days. The SCS was not turned off at any time during the labor and delivery. Conclusion. SCS was safe for implantation in our case study of a pregnant woman. This may constitute a new indication for SCS in patients otherwise successfully managed with non-interventional modalities for pain control.     

Factors Affecting Impedance of Percutaneous Leads in Spinal Cord Stimulation

Objectives. Although the load impedance of a pulse generator has a significant effect on battery life, the electrical impedance of contact arrays in spinal cord stimulation (SCS) has not been extensively studied. We sought to characterize the typical impedance values measured from common quadripolar percutaneous SCS contact arrays. Methods. In 36 patients undergoing percutaneous trial stimulation for various chronic pain conditions, bipolar impedance between adjacent contacts of 64 leads with 9 mm center‐to‐center spacing was measured in two different vertebral level regions, cervical (C3–C7) and lower‐thoracic (T7–T12). Multiple linear regression was applied to analyze the contribution of six variables to the biological tissue portion of the impedance (excluding the resistance of the lead wires). Results. The median impedance in the cervical region (351 ± 90 Ω) was significantly lower (36%, p < 0.001) than in the lower‐thoracic region (547 ± 151 Ω). In addition, time since implant had a weaker but still significant effect on tissue impedance. Conclusions. Results from finite‐difference mathematical modeling of SCS suggest that the difference in tissue impedance related to vertebral level may be due to the dorsoventral position of the lead in the epidural space. The presence of a larger space between the triangularly shaped dorsal part of the vertebral arch and the round shape of the dural sac in the lower‐thoracic region increases the likelihood that the stimulating lead will not make dural contact, and thus “see” an increased impedance from the surrounding epidural fat. This implies that the energy requirements for stimulation in the thoracic region will be higher than in the cervical region, at least during the acute phase of implant.     

Four Year Follow‐up of Dual Electrode Spinal Cord Stimulation for Chronic Pain

This paper reports on 80 patients using dual electrode, spinal cord stimulation (SCS) over a four‐year period Implant status, stimulation mode, anode‐cathode configuration (array), cathode position, paresthesia overlap, explantation rates, complications, Visual Analog Scores (VAS), and overall satisfaction were examined in patients implanted with dual 8 contact, staggered, percutaneous electrodes. All patients had undergone implantation for chronic axial and extremity pain [e.g., Failed Back Surgery Syndrome (FBSS), Complex Regional Pain Syndrome (CRPS)]. Outcomes were evaluated in view of our previous reports in this same group at 24 and 30 months 1 , 2 . Data was collected by a disinterested third party. At 48 months, 18 of the original 80 patients were lost to follow‐up. Of the 62 patients contacted, 33 remained implanted and 29 (47%) had been explanted. After an average evaluation of 85 arrays (PainDoc, Advanced Neuromodulation Systems, Plano, Texas), 88% of patients reported using one or two “best” arrays (bipolar or guarded tripolar) to maintain favorable paresthesia overlap (89%), VAS reduction (8.1 to 4.9), and overall patient satisfaction (63%). These arrays were most commonly positioned about the physiologic midline of the COL3–4 vertebral segments for upper extremity pain, and the T9–10 vertebral segments for low back and lower extremity pain. In contrast to our initial reports where essentially all patients preferred more than two arrays to maintain “best” paresthesia overlap and outcome, only 12% of these same patients maintained this trend in this long‐term follow‐up study. The arrays most commonly selected long‐term as the “best” ones (88% of all electrodes) were narrow (adjacent contact) bipoles and guarded cathode tripoles (< 8 contacts). Thirty‐five percent of patients with thoracic implants achieved paresthesia in the low back at 48 months. Explantation rates and overall patient satisfaction were significantly affected by painful radio frequency (RF) antenna coupling. This data supports the efficacy of dual electrodes in optimizing long‐term SCS paresthesia overlap and complex pain outcomes.     

Burst Spinal Cord Stimulation in Pregnancy: First Clinical Experiences

ObjectivesSpinal cord stimulation (SCS) is a treatment for chronic neuropathic pain. It is based on the delivery of electric impulses to the spinal cord, traditionally in a regular square-wave pattern (“tonic” stimulation) and, more recently, in a rhythmic train-of-five “BurstDR” pattern. The safety of active SCS therapy in pregnancy is not established, and recommendations are based on limited casuistic evidence. We present in this study clinical data on a case series of six women treated with burst SCS during pregnancy. In addition, we present the ultrasonographic flow measurements of fetal and uteroplacental blood flow in a pregnant patient.Materials and MethodsPatients were included if they had been implanted with a full SCS system at Aarhus University Hospital, Denmark, between 2006 and 2020 and received active burst SCS stimulation during a pregnancy. Telephone interviews were conducted, including details on SCS therapy, medication, pregnancy course and outcome, and health status of the offspring. In one patient, the uteroplacental and fetal blood flow was assessed in gestational week 29 by Doppler flow measurements performed during both ON and OFF phases of the SCS system.ResultsSix patients were included with a total of 11 pregnancies. Three pregnancies ended in miscarriages, all in the same patient who had preexisting significant risk factors for miscarriage. Eight resulted in a live-born child with normal birth weight for gestational age; seven were born at term, and one was born late preterm, in gestational week 36. Ultrasonographic Doppler flow, measured in one patient, was normal and did not reveal any immediate changes between burst SCS ON and OFF. Seven children were reported healthy with normal neurodevelopment and one physically healthy but with developmental delays.ConclusionsThe data presented in this study add to the accumulating evidence of the safety of SCS in pregnancy.     

Spinal Cord Stimulation: A 20‐Year Retrospective Analysis in 260 Patients

Introduction. Spinal cord stimulation (SCS) is used clinically by many pain physicians and neurosurgeons alike without regard to their own outcome data. Methods. We reviewed our 20‐year experience retrospectively of patients receiving SCS implants and analyzed our data by pain type and group. Results. We present 260 patients, 140 men and 120 women. The most frequent type of pain in our series was neuropathic pain in 44.25% and the most frequent diagnosis was peripheral vascular disease (PVD) with 98 cases. The second was failed back surgery syndrome (FBSS) with 65 cases and the third was complex regional pain syndrome type I (CRPS I), with 40 cases. In CRPS group, the mean visual analog scale (VAS) of this group was 77.89 ± 13.38. In total, 5% had no pain relief, 40% had poor pain relief, 47.5% had good pain relief, and 7.5% had excellent pain relief. In FBSS group, the mean VAS was 79.62 ± 11.69 mm. A total of 13.80% had no pain relief at all, 35.39% had poor pain relief, 50.76% had good pain relief, and there were no patients in this group who had complete pain relief. A total of 98 patients, 78 men and 20 women, were diagnosed with PVD. The mean VAS of this group was 69.75 ± 14.36 mm. A total of 11.22% had poor pain relief, 87.75% had good pain relief. One patient had complete pain relief and all patients in this group perceived at least some improvement in their symptoms. The rate of complications was close to 28% in our overall sample. Conclusions. In conclusion, we demonstrated the utility over time of this type of treatment is comparable with other series of efficacy of SCS. The analgesic efficacy was close to 65% in the overall group. The therapy was not free of complications. The preponderance of our patients was patients with the diagnosis of PVD and our results in this group of patients were excellent. These excellent results of more than 90% improvement suggest to us that SCS be considered as a first‐line approach to the clinical management of patients with pain and ulcer of PVD.     

Spinal cord stimulation for neuropathic pain

Spinal cord stimulation (SCS) is used for more than 40 years to treat localized chronic medically refractory neuropathic pain involving limb(s) and trunk. The most frequent indications remain complex regional pain syndrome (CRPS) failed back surgery syndrome (FBSS), and peripheral neuropathy. Stimulation-induced paresthesias, perceived by the patient, prevent blinded evaluation and increase the placebo effect, decreasing the credibility of the tonic SCS efficacy. Retrospective studies reported that about 50% of the patients are improved more than 50% at short-term, but long-term improvement is less. Several comparative randomized trials (RCT) are now available. In CRPS, a RCT demonstrated the superiority of SCS plus physiotherapy compared to physiotherapy alone. In FBSS, two RCTs have shown that SCS was superior to reoperation and conventional medical treatment, (CMM) respectively. New stimulation waveforms, namely burst, high frequency (10 KHz) stimulation and close-loop SCS, have been proposed recently to avoid the perception of paresthesias and/or increase the pain relief. RCTs in FBSS have suggested that these new SCS modalities were as least as efficient than conventional tonic SCS and perhaps slightly superior. Two RCTs confirmed SCS efficacy in painful diabetic neuropathy in comparison with CMM. Complications are frequent (hardware dysfunction or migration, superficial infection) but exceptionally serious. Consequently, the risk/benefit ratio is favorable to SCS, considering that chronic pain patients undergoing this procedure are usually resistant to all the other therapies.     

Combined Spinal Cord and Peripheral Nerve Field Stimulation for Persistent Post‐Herniorrhaphy Pain

Objectives: Chronic post‐hernia pain is a common complication after inguinal herniorrhaphies. Peripheral nerve field stimulation (PNFS) and spinal cord stimulation (SCS) are two new promising treatment modalities. Four patients with persistent neuropathic post‐hernia pain were recruited for this prospective study. Materials and Methods: Electrodes were inserted into the epidural space of the spinal canal and into the subcutaneous tissue in the inguinal region during a single surgical procedure. During a 14‐day trial, double‐blind stimulation was performed via an external stimulator: three days using the spinal electrode (SCS), three days using the inguinal electrode (PNFS), three days using both (SCS + PNFS), and five days off, with an alternating order from patient to patient. During the trial, pain intensity was assessed thrice daily by the visual analog scale. Additionally, pain intensity and quality of life (QOL) were assessed before and after surgical intervention by the Brief Pain Inventory, SF36 scale, and Pain Disability Index. Results: All patients had a marked pain reduction during the trial phase, and this reduction was more prominent when both electrodes were activated simultaneously (p < 0.001). At the late follow‐up, a significant pain reduction and improvement of QOL was observed in three patients. Conclusions: Both SCS and PNFS are effective in treating post‐hernia pain, but the magnitude of pain reduction was more prominent with concomitant stimulation. Combined PNFS and SCS should be considered for patients with a less than optimal response to either SCS or PNFS. More studies are necessary to address the cost‐effect issues of this new approach to treatment.     

Subcutaneous Stimulation as an Additional Therapy to Spinal Cord Stimulation for the Treatment of Lower Limb Pain and/or Back Pain: A Feasibility Study

Objective: The objective of this study was to demonstrate the efficacy of subcutaneous stimulation (SubQ) as an additional therapy in patients with failed back surgery syndrome (FBSS) with chronic refractory pain, for whom spinal cord stimulation (SCS) was unsuccessful in treating low back pain. Study Design: Case series. Materials and Methods: FBSS patients with chronic limb and/or low back pain whose conventional therapies had failed received a combination of SCS (8‐contact Octad lead) and/or SubQ (4‐contact Quad Plus lead(s)). Initially leads were placed in the epidural space for SCS for a trial stimulation to assess response to suppression of limb and low back pain. Where SCS alone was insufficient in treating lower back pain, leads were placed superficially in the subcutaneous tissue of the lower back, directly in the middle of the pain area. A pulse generator was implanted if patients reported more than 50% pain relief during the trial period. Pain intensity for limb and lower back pain was scored separately, using visual analog scale (VAS). Pain and Quebec Back Pain Disability Scale (QBPDS) after 12‐month treatment were compared with pain and QBPDS at baseline. Results: Eleven FBSS patients, five male and six female (age: 51 ± 8 years; mean ± SD), in whom SCS alone was insufficient in treating lower back pain, were included. In nine cases, SubQ was used in combination with SCS to treat chronic lower back and lower extremity pain. In two cases only SubQ was used to treat lower back pain. SCS significantly reduced limb pain after 12 months (VAS_bl: 62 ± 14 vs. VAS_12m: 20 ± 11; p= 0.001, N= 8). SubQ stimulation significantly reduced low back pain after 12 months (VAS_bl: 62 ± 13.0 vs. VAS_12m: 32 ± 16; p= 0.0002, N= 10). Overall pain medication was reduced by more than 70%. QBPDS improved from 61 ± 15 to 49 ± 12 (p= 0.046, N= 10). Furthermore, we observed that two patients returned to work. Conclusion: SubQ may be an effective additional treatment for chronic low back pain in patients with FBSS for whom SCS alone is insufficient in alleviating their pain symptoms.     

Direct Sciatic Nerve Electrical Stimulation for Complex Regional Pain Syndrome Type 1

ObjectiveFoot and leg pain in complex regional pain syndrome (CRPS) presents a challenge even with neuromodulation techniques such as spinal cord stimulation (SCS). We report our experience with a novo technique of direct sciatic nerve electrical stimulation (DISNES) for intractable foot and leg pain in CRPS I.Materials and MethodsFollowing Research Ethics Board (REB) approval, data were gathered for 16 patients (10 women and 6 men, age 26–61 years) who had been subjected to ipsilateral DISNES. All 16 patients had failed conventional medical management. As well, seven subjects were previously treated with SCS for CRPS I pain. These subjects reported pain relief in the thigh and leg, however the SCS was unable to alleviate the disabling foot pain despite varied and multiple programming techniques. The remaining nine subjects were treated primarily with DISNES. Evaluation was done using visual analog scale (VAS), Oswestry Disability Index version 2 (ODI), and quality of life (EQ-5D and SF-36) scores done both pre-DISNES and at two follow-ups.ResultsVAS scores decreased by 59% at follow-up (F/U) 1 (P = 0.00001) and 46% F/U 2. ODI improving by 40% F/U 1 (P = 0.0038) and 37% F/U 2. SF-36 scores improved by 69% F/U 1 (P = 0.015) and 80% F/U 2. EQ-5D scores improved significantly by F/U 1 (P = 0.00030) but insignificantly at F/U 2 (P = 0.81). There was also a rapid resolution of autonomic features such as edema, hyperemia, and allodynia (within 7–10 days). Three subjects returned to work post-DISNES.ConclusionOur study shows that DISNES helps to control the disabling foot pain in CRPS I, thus improving the quality of life, improving ambulation and decreasing disability. DISNES also alleviates autonomic features and dystonia in CRPS I. Further studies are needed to determine long-term efficacy as this study pool is limited in size and follow-up period.     

Peripheral Nerve Stimulation: A Percutaneous Minimally Invasive Approach

We report on the use of a new percutaneous technique for peripheral nerve stimulation (PNS) treatment of chronic pain. A 56‐year‐old woman was diagnosed with algodystrophic syndrome, now called Complex Regional Pain Syndrome, type 2 (CRPS2), due to a lesion of the right medial nerve despite surgical revascularization, angioplasty and stent insertion. After a successful 10‐day trial of PNS via a percutaneous quadripolar lead in the interscaline space, an implantable pulse generator was implanted in the abdominal subcutaneous tissue and connected to the subcutaneous lead via an extension. After one year of follow‐up, the patient was still experiencing good pain relief. We conclude that this novel percutaneous PNS technique offers the advantage of being a minimally invasive approach that can be easily adopted for the management of chronic pain.     

Evolving Patterns of Spinal Cord Stimulation in Patients Implanted for Intractable Low Back and Leg Pain

The objective of this study was to examine the programming strategies used in patients with intractable low‐back pain treated with epidural spinal cord stimulation (SCS) utilizing paddle electrodes and a radio frequency (RF) stimulator. Programming strategies were examined in a group of patients implanted with a 16‐contact paddle electrode and a dual channel RF receiver to treat chronic low‐back pain. Baseline data included previous surgical history information, leg and low back pain severity and characteristics, and routine demographic information. Outcome measurements included the visual analog scale (VAS) 1 , patient pain relief rating scale, and programming parameters. Patients rated their pain relief on a 5‐point scale where 4 = excellent, 3 = good, 2 = fair, 1 = poor and 0 = none. Success was determined to be a pain relief score of “fair” or above. Data were collected during patient visits or by mail, at approximately 6, 12, and 24 months, postoperatively. Immediate postop data were available in 16 patients, 6‐month data in 21 patients, 1‐year data in 20 patients, and 2‐year data in 10 patients, and analyzed for the purposes of examining programming strategies. The most common location for the tip of the electrode (lead) was found to be in the middle of the 8th thoracic vertebrae (N = 26). At the immediate postop assessment, the majority of cathodes were activated in the upper half of T9. By the 6‐month follow‐up, the majority of cathodes had shifted to the bottom of T9 and top of T10. Overall 88% of cathode locations were changed at one or more study visits. At 2 years, 86% of the programs used four or more active contacts. At 6 months, 83% of the patients reported that the therapy was a success, at 1 year, success was 94%, and by 2 years, success was 75%. Both SCS and chronic pain are dynamic processes. Complex pain patterns, such as the ones of patients who have pain in the low back and in one or both lower extremities, require a high degree of flexibility in the implanted SCS system. The system must provide the capability to redirect the current electronically over at least two segments of the spinal canal, to electronically steer the current in a medio‐lateral direction, and to activate multiple electrical contacts simultaneously. The willingness and ability to provide extensive reprogramming in the long term follow‐up is also of the utmost importance. Pain and its treatment with SCS is a dynamic process.     

Subcutaneous Peripheral Nerve Stimulation with Inter‐lead Stimulation for Axial Neck and Low Back Pain: Case Series and Review of the Literature

Objectives: While pain in the extremities often responds to treatment using spinal cord stimulation (SCS), axial pain is notoriously refractory to SCS. Interest in subcutaneous peripheral nerve stimulation (SQ PNS) as an alternative to SCS has emerged, but the most appropriate electrode locations and neurostimulator programming techniques are not yet clear. Methods: A retrospective review was conducted of consecutive patients evaluated from August 2009 to December 2010 who had undergone trial of SQ PNS with inter‐lead stimulation for axial spine pain. Patients proceeding to implant were followed postoperatively with routine clinical visits and a survey form at last follow‐up. Ultrasound was used intraoperatively to ensure placement of electrodes at the appropriate depth in patients with larger body mass index. Primary outcome was patient‐reported pain relief at last follow‐up. Literature review was conducted by searching MEDLINE (1948–present) and through an unstructured review by the authors. Results: Ten patients underwent trial of SQ PNS and six proceeded to permanent implantation. Fifty percent (3/6) of implanted patients preferred neurostimulation programming that included inter‐lead stimulation (“cross‐talk”). Average duration of postoperative follow‐up was 4.5 months (range 2–9 months). Average patient‐reported pain relief at last follow‐up was 45% (range 20–80%). One patient required re‐operation for migration. Patients not proceeding to implant had paresthesia coverage but no analgesia. Conclusion: SQ PNS is a promising therapy for axial neck and back pain based on a small cohort of patients. Ultrasound was useful to assist with electrode placement at the most appropriate depth beneath the skin. While inter‐lead stimulation has been preferred by patients in published reports, we did not find it clearly influenced pain relief. Future investigations should include a randomized, controlled study design, as well as defined implantation technique and neurostimulator programming algorithms.     

Spina Bifida Occulta as a Relative Contraindication for Percutaneous Retrograde Lead Insertion for Sacral Nerve Root Stimulation

Percutaneous retrograde lead insertion for sacral nerve root stimulation is a newly described technique being applied to a variety of pain disorders. The success of the procedure rests in a defined epidural space such that there is unimpeded progression of the lead into the desired location. It is hypothesized that any condition that results in anatomic compromise of the epidural space would prevent the success of the procedure. Two patients with biopsy‐proven interstitial cystitis and intractable pain were referred to the senior author for evaluation. Percutaneous retrograde lead insertion for sacral nerve root stimulation was performed on these patients in a standard fashion 1 , 2 . Intraoperative fluoroscopy verified the diagnosis of spina bifida occulta. In one patient, implantation was completed percutaneously, but later two of the leads were found to have been placed intradurally. In another patient, repeated attempts at passing the epidural lead distal to the congenital defect were unsuccessful, and the percutaneous procedure was aborted. In conclusion, we have found that the diagnosis of spina bifida occulta, or any other condition in which the epidural space is anatomically disrupted, is a relative contraindication for this procedure. Preoperative roentograms of the lumbar spine may be helpful in avoiding technical difficulties due to this diagnosis.