Technical Performance of Percutaneous and Laminectomy Leads Analyzed by Modeling

The objective of this study was to compare the technical performance of laminectomy and percutaneous spinal cord stimulation leads with similar contact spacing by computer modeling. Monopolar and tripolar (guarded cathode) stimulation with both lead types in a low‐thoracic spine model was simulated using UT‐SCS software. Dorsal column and dorsal root fiber thresholds were calculated as well as the area of recruited fibers in the dorsal columns, the rostrocaudal span of recruited dorsal root fibers and the energy consumption at discomfort threshold. Tripolar stimulation is superior to monopolar stimulation in the recruitment of the dorsal columns, a percutaneous lead recruits a ～12% larger dorsal column area than a laminectomy lead does. This difference is reduced when the contact spacing of the lead models is the same. A percutaneous lead with significant wire impedance (140 Ohms) consumes ～115–240% more energy, whereas the same lead with negligible wire impedance consumes ～40–85% more energy. A deterioration of all performance parameters is predicted when a percutaneous lead is placed more dorsally in the epidural tissue. When positioned next to the dura mater, a percutaneous lead has a similar performance (fiber recruitment in the dorsal columns and the dorsal roots) as a laminectomy lead with similar contact spacing, but substantially higher energy consumption. The superior clinical performance of the laminectomy lead is most probably due to the difference in volume and insertion technique of the two lead types.     

A New and Alternative Leads Positioning for Complex Regional Pain Syndrome Treatment: Paraforaminal Stimulation

We present a case of a female patient suffering from type I complex regional pain syndrome (CRPS) who developed “mirror imaging” of her CRPS and was successfully treated with dual spinal cord stimulation (SCS) in the paraforaminal epidural space. This patient initially had unilateral pain that was unsuccessfully treated with midline SCS and single‐lead lateral epidural lead placement “paraforaminally.” One year later, because we believed that paraforaminal stimulation would preferentially stimulate primary sensitized afferents innervating the painful area, we reperformed SCS with two leads positioned laterally and paraforaminally close to the roots within the epidural space. After repositioning and after 1 year of paraforaminal stimulation, there was significant improvement in the patient's symptoms, resolving all unilateral and “mirrored” symptoms. We conclude that paraforaminal stimulation may be a valid therapeutic option for the treatment of CRPS.     

Challenges to Setting Spinal Cord Stimulator Parameters During Intraoperative Testing: Factors Affecting Coverage of Low Back and Leg Pain

Objective. Spinal cord stimulator (SCS) parameter settings have been well studied; however, the goal of this exploratory study was to examine the SCS parameters used during intra‐operative stimulation (IOS) at trial lead placement. Methods. In this retrospective study, we report the IOS parameter settings for 22 patients who underwent thoracic SCS lead trial for treatment of refractory low back and/or leg pain. Results. Paresthesia coverage was shown to differ depending upon the pain syndrome and the region involved (back and/or leg, p = 0.03). Certain stimulation parameters were demonstrated to be linked, including pulse width with rate (p = 0.04) and bipolar activation distance with amplitude (p < 0.01). Important variations in field configuration practice patterns also emerged. Conclusions. Larger prospective studies are required to confirm and extend the current results. The ultimate goal for this report is to establish a foundation for future studies to create an evidence‐based standardized algorithm for IOS to enhance the success rate of SCS trial screening.     

A New Spinal Cord Stimulation System Effectively Relieves Chronic,Intractable Pain: A Multicenter Prospective Clinical Study

Objectives. A prospective, open label, multicenter clinical trial confirmed the functionality of a new spinal cord stimulation (SCS) system for the treatment of chronic, intractable pain of the trunk and/or limbs. Materials and Methods. Sixty‐five subjects tested a rechargeable 16‐channel SCS system with individual current control of each contact on one or two percutaneous eight‐contact epidural leads. After baseline measurements, subjects were tracked on pain ratings and complication rates for up to 18 months. Results. After a trial period, 75% of subjects underwent permanent implantation of the entire SCS system. More than one‐half the implanted subjects experienced 50% or greater relief of pain after permanent implantation; some subjects reported relief of 90% or more of their pain. The most common complications after permanent implantation were lead migration, uncomfortable stimulation, and component failure; most resolved after reprogramming or device replacement. Conclusions. The new SCS system provided good pain relief to a majority of subjects, and the results confirm a favorable safety and efficacy profile for the SCS system.     

Cervical Spinal Cord Stimulation for Pain: A Report on 41 Patients

The objectives of this study were to assess the effectiveness of cervical spinal cord stimulation in the management of intractable pain syndromes affecting the upper limb and face and to assess the reliability of a specific electrode system in this mobile environment. Forty‐one patients, aged 26–76 years (median 48) with neuropathic or ischemic pain underwent the cervical epidural implantation of identical dual two‐contact paddle (four contacts per system) laminectomy electrodes. Follow‐up (from 5 months to 11 years, 3 months; median 4 years, 7 months) was by multiple consultations carried out by the surgeon and/or in a nurse‐led specialist clinic. Overall, 68% obtained sustained pain relief, rated as significant in 51% of the total. Facial pain did not respond. Ischemic syndromes responded well. Lead fracture rate was 15% of the original (11% of the total including replacements) and only 7% (5%) became dislodged.We conclude that the electrode system described provides reliable and sustained cervical cord stimulation. The outcomes are comparable with thoracic cord stimulation for neuropathic and ischemic syndromes.     

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.     

Tissue Temperature Increases by a 10 kHz Spinal Cord Stimulation System: Phantom and Bioheat Model

ObjectiveA recently introduced Spinal Cord Stimulation (SCS) system operates at 10 kHz, faster than conventional SCS systems, resulting in significantly more power delivered to tissues. Using a SCS heat phantom and bioheat multi-physics model, we characterized tissue temperature increases by this 10 kHz system. We also evaluated its Implanted Pulse Generator (IPG) output compliance and the role of impedance in temperature increases.Materials and MethodsThe 10 kHz SCS system output was characterized under resistive loads (1–10 KΩ). Separately, fiber optic temperature probes quantified temperature increases (ΔTs) around the SCS lead in specially developed heat phantoms. The role of stimulation Level (1–7; ideal pulse peak-to-peak of 1–7mA) was considered, specifically in the context of stimulation current Root Mean Square (RMS). Data from the heat phantom were verified with the SCS heat-transfer models. A custom high-bandwidth stimulator provided 10 kHz pulses and sinusoidal stimulation for control experiments.ResultsThe 10 kHz SCS system delivers 10 kHz biphasic pulses (30-20-30 μs). Voltage compliance was 15.6V. Even below voltage compliance, IPG bandwidth attenuated pulse waveform, limiting applied RMS. Temperature increased supralinearly with stimulation Level in a manner predicted by applied RMS. ΔT increases with Level and impedance until stimulator compliance was reached. Therefore, IPG bandwidth and compliance dampen peak heating. Nonetheless, temperature increases predicted by bioheat multi-physic models (ΔT = 0.64°C and 1.42°C respectively at Level 4 and 7 at the cervical segment; ΔT = 0.68°C and 1.72°C respectively at Level 4 and 7 at the thoracic spinal cord)–within ranges previously reported to effect neurophysiology.ConclusionsHeating of spinal tissues by this 10 kHz SCS system theoretically increases quickly with stimulation level and load impedance, while dampened by IPG pulse bandwidth and voltage compliance limitations. If validated in vivo as a mechanism of kHz SCS, bioheat models informed by IPG limitations allow prediction and optimization of temperature changes.     

The Prospective Evaluation of Safety and Success of a New Method of Introducing Percutaneous Paddle Leads and Complex Arrays With an Epidural Access System

Objectives: Spinal cord stimulation (SCS) has become a mainstay in the continuum of care for patients suffering from chronic neuropathic pain of the trunk and limbs. Options for placing these devices have included a percutaneous method of using an epidural needle to place a cylindrical (percutaneous) lead to stimulate the spinal cord, or an open laminotomy method for placing a paddle lead at the location of the surgical decompression of the laminae. Both of these methods have been successful in a high percentage of patients, but neither have been ideal. Limitations of the percutaneous leads have been inefficiency of power delivery, inability to achieve desired depth of stimulation in the spinal cord, occasional lead migration and difficulty covering complex pain patterns. Limitations of the paddle lead have been the need for surgical laminotomy, inability to steer the lead once placed, limits on placement in the vicinity of the surgical decompression, and a perceived risk of increased bleeding and trauma to the tissue. These factors have led many minimally invasive spine specialists to seek new options for SCS. This paper presents the initial US experience with a newly approved device to place both paddle leads, and multi‐lead arrays into the epidural space via a percutaneous Seldinger‐guided approach through a single needle placement. We will both describe the technique and review the outcomes of some of the early cases. Materials and Methods: After Investigational Review Board clearance, patients consented to data collection in a prospective fashion regarding the use of a new percutaneous epidural introducer (Epiducer, St. Jude Neurological, Minneapolis, MN, USA) to place paddle leads and complex lead arrays. The patients underwent education regarding expectations and risks of the procedure consistent with our normal preoperative period. Patients underwent preoperative anesthesia screening and proper testing as outlined by the Joint Commission on Hospital Accreditation, and were given the opportunity to ask questions concerning the procedure. Once the patient wished to move forward, they were consented using the approved case reporting form and followed during the course of their care. The initial cases were performed in West Virginia with subsequent cases following at the other centers involved in this analysis. The outcomes of this analysis focused on three areas:

• 1 The technical success in placing the percutaneous sheath. This included the ability to successfully complete:
  • ? epidural access with a 14‐gauge Tuohy needle
  • ? ability to place a styleted guidewire
  • ? ability to introduce the introduction system over the wire into the epidural space
  • ? ability to remove the guidewire and introduction tip leaving the 10‐gauge sheath intact
• 2 The ability to place the desired lead or leads into the epidural space via the percutaneous introduction sheath.
• 3 The presence of any major adverse event which were defined as:
  • ? nerve injury
  • ? paraplegia
  • ? worsening of baseline pain
  • ? epidural hematoma
  • ? epidural infection
  • ? dural tear
  • ? dural rent
  • ? retained device that could not be removed

This information was carefully recorded for each implant, and summarized in this communication. Results: During the initial 30 days of the evaluation period, 43 epidural introduction systems were attempted in 38 patients. In patients in whom more than one paddle lead was placed, the system required the reinsertion of the guidewire through the Epiducer, removal of the Epiducer, and rewiring over the guidewire. This is necessary because the diameter of a paddle lead does not allow two or three leads to be placed without rewiring the system. The success of placement was 42/43, with inability to access the epidural space in one patient in whom ligamentum flavum hypertrophy was present on the preoperative imaging study. In all patients, the system was placed at the L1–L2 level, or lower, based on the Food and Drug Administration labeling. The total numbers of leads placed were 75, with both paddle and percutaneous arrays implanted successfully. There were no adverse events during this prospective surveillance evaluation. Ten patients complained of soreness at the entry site and post‐procedure stiffness. These complaints were treated with ice, rest, and analgesics and resolved without incident. Conclusion: This paper describes the initial US cases of the placement of a paddle lead via a minimally invasive percutaneous method, as well as complex cylindrical arrays with a single needle entry to the epidural space. The device functioned successfully and presented a safe option for placing paddle leads and complex arrays.     

Triple Leads Programmed to Perform as Longitudinal Guarded Cathodes in Spinal Cord Stimulation: A Modeling Study

Objective: In spinal cord stimulation, neurosurgeons increasingly tend to implant dual leads. Dual leads (longitudinal bipole/tripole) provide medio‐lateral control over the recruited dorsal column (DC) area by steering the injected cathodal currents. However, the DC recruited area is suboptimal when dual aligned leads straddling the midline programmed as longitudinal guarded cathodes (+−+) are used instead of a single lead placed over the spinal cord midline with the same configuration. As a potential improvement, an additional third lead between the two aligned leads is modeled to maximize the medio‐lateral extent of the DCs at the low‐thoracic vertebral region (T10‐T12). Methods and Materials: The University of Twente Spinal Cord Stimulation software (UT‐SCS) is used in this modeling study. Longitudinal guarded cathodes were modeled on the low‐thoracic vertebral region (T10‐T12) using percutaneous triple lead configurations. The central lead was modeled over the spinal cord midline and the two lateral leads were modeled at several transverse distances to the midline lead. Medio‐lateral field steering was performed with the midline lead and the second lead on each side to achieve constant anodal current ratios and variable anodal current ratios. Results: Reducing the transverse lead separation resulted in increasing the depths and widths of the recruited DC area. The triple lead configuration with the least transverse separation had the largest DC recruited area and usage range. The maximum DC recruited area (in terms of both depth and width) was always found to be larger under variable anodal current ratio than constant anodal current ratio conditions. Conclusions: Triple leads programmed to perform as longitudinal guarded cathodes provide more postoperative flexibility than single and dual leads in covering a larger width of the low‐thoracic DCs. The transverse separation between the leads is a major determinant of the area and distribution of paresthesia.     

Spinal Cord Stimulation for Failed Back Surgery Syndrome

Objective. The purpose of this study is to evaluate the effectiveness of modern spinal cord stimulation (SCS) for the treatment of failed back surgery syndrome (FBSS). Materials and Methods. Thirty patients were treated with SCS between December 1992 and January 1998 for low back and radicular pain after multiple failed back surgeries. Permanent systems were implanted if trial stimulation led to > 50% pain reduction. Median long‐term follow‐up was 34 months (range, 6–66 months). Severity of pain was determined postoperatively by a disinterested third party. Results. Overall, 12 of the 16 patients (75%) who received permanent implants continued to report at least 50% relief of pain at follow‐up. All six patients who underwent placement of laminectomy‐styled electrode for SCS in the thoracic region had > 50% pain relief at long‐term follow‐up. Visual analog scores decreased an average of 3.2 (from 8.6 preoperatively to 5.4 postoperatively). Patients undergoing SCS placement via laminectomy in the thoracic region experienced an average decrease of 4.9 in VAS, whereas those who underwent percutaneous placement of thoracic leads had an average decrease of 2.5. Conclusions. SCS is an effective treatment for chronic low back and lower extremity pain which is refractory to conservative therapy and which is not amenable to corrective anatomic surgery. Though our patient population is small, our results imply that the laminectomy‐style electrodes in the thoracic region achieve better long‐term effectiveness than percutaneous leads.     

Spinal Cord Stimulation for the Treatment of Upper and Lower Extremity Neuropathic Pain due to Lyme Disease

Background. Lyme disease is caused by Borrelia, a bacterium transmitted by the bite of a deer tick. A slow developing encephalopathy or an axonal polyneuropathy with distal paresthesia and spinal or radicular pain rarely occurs and can be hard to treat. Materials and Methods. We report here the case of a 44‐year‐old woman with four‐limb, intolerable, neuropathic pain as sequelae to Lyme disease, which was resistant to conservative measures and was treated successfully with concurrent, thoracic, and cervical percutaneous spinal cord stimulation (SCS). Results. After 18 months of therapy and follow‐up, this patient's analgesia, as a result of SCS, continues to be excellent, with almost complete subjective pain relief and cessation of adjuvant analgesic medication. Conclusions. SCS may be efficacious for the treatment of neuropathic pain due to Lyme disease.     

Spinal Cord Stimulation in the Management of Pain from Brachial Plexus Avulsion

This is a retrospective study of four patients suffering from brachial plexus root avulsion of traumatic origin. Spinal cord stimulation was used to treat pain in all patients. A seven‐contact electrode was percutaneously introduced in the epidural cervical space and under fluoroscopic control, advanced to the level were stimulation provoked a tingling sensation in the painful region. A stimulation trial was performed for 2 weeks and during this period the patients showed significant pain relief, so the system was permanently implanted. A significant difference of more than three points in the pain between the first and the last follow‐up (0–9 months) on the Visual Analog Scale was obtained with a steady and progressive decrease of the pain scores.     

The Prevalence of Elevated Impedances and Magnetic Resonance Imaging Ineligibility Following Implantation of 10 kHz Spinal Cord Stimulation Devices: A Retrospective Review

ObjectivesSpinal cord stimulation (SCS) is increasingly utilized in the treatment of multiple chronic pain conditions. However, patients will continue to experience other medical issues and the potential for future magnetic resonance imaging (MRI) needs must not be overlooked. SCS devices have device-specific MRI conditional labeling and if impedances are elevated the patient may not be able to obtain an MRI. With 10 kHz SCS devices specifically, an impedance value above 10,000 ohms (Ω) is MRI ineligible. The primary objective of this article was to report the incidence of elevated impedances with a multilumen lead design per electrode, per lead, and to describe the total number of MRI ineligible patients due to elevated impedances using 10 kHz SCS cutoff values. The secondary objective was to determine whether certain patient demographics or surgery characteristics put patients at increased risk of elevated impedances.Materials and MethodsWe performed a retrospective review of 327 patients who were implanted with a 10 kHz SCS device between January 2015 and November 2020. Regression models were fitted to determine associations between MRI ineligibility status with clinical characteristics including age, sex, BMI, lead location, implantable pulse generator (IPG) location, and time since implant.ResultsWe found elevated impedances with subsequent MRI ineligibility in 13 patients (4.0%). Regression analysis did not identify any associations with MRI ineligibility and patient risk factors including age, sex, body mass index, lead location, IPG location, and follow-up time since implant.ConclusionWe found the prevalence of elevated impedances above 10,000 Ω to be 4% of implanted patients. This information is important for patients and physicians alike and should be considered when device selection is occurring in the pre-operative visits.     

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.     

Acute vs. Prolonged Screening for Spinal Cord Stimulation in Chronic Pain

Spinal cord stimulation (SCS) was performed to test the hypothesis that pain relief data during acute (15 minute intraoperative) and prolonged (5 day) SCS screening have equivalent predictive value for long‐term successful SCS control of chronic low back pain and/or lower extremity pain. A retrospective series of patients with chronic low back and/or lower extremity pain underwent either percutaneous or open (ie, laminectomy) SCS implantation during which acute intraoperative followed by prolonged screening trials for percentage pain relief (%PR) were performed. Data were analyzed for (a) correlation between positive predictive value (PPV) of acute and prolonged SCS screening for %PR and (b) PPV of acute vs. prolonged screening %PR for long‐term SCS %PR. Fifty‐four patients (male/female = 38/16; mean age ± SEM = 54.2 ± 2.0 years) underwent thoracic (T) (mean level = T9.1 ± 0.4) percutaneous (n = 33) and laminectomy (n = 21) implantation of SCS for acute (15 minute intraoperative) and prolonged (5.0 ± 0.3 days) SCS screening of pain relief. Correlation between successful (> 50%PR) pain relief during acute (n = 53/54, PPV = 98%) and prolonged (n = 47/52, PPV = 90%) screening was significant (Spearman Rank Correlation Coefficient, SRCC = 0.462, p < 0.01). After permanent SCS implantation, at mean follow‐up = 9.4 ± 1.5 months, acute and prolonged SCS screening %PR PPV's were each statistically significant for predicting long‐term SCS relief of chronic pain (n = 31/38, PPV = 82% and n = 31/36, PPV = 86%, SRCC = 0.462 and 0.433, respectively, p < 0.01). We conclude that successful pain relief during acute SCS screening is highly correlated with successful prolonged SCS screening of chronic low back and/or lower extremity pain relief. Acute and prolonged SCS screening appear to have equivalent predictive value for successful long‐term SCS control of chronic low back and/or lower extremity pain. These preliminary results suggest potential justification for eliminating prolonged and retaining acute (intraoperative) SCS screening for selection of permanent SCS implantation candidates.     

Spinal Cord Stimulation in Conjunction With Peripheral Nerve Field Stimulation for the Treatment of Low Back and Leg Pain: A Case Series

Background. The treatment of chronic low back and leg pain remains a difficult medical challenge, particularly for patients with postlaminectomy syndrome. While spinal cord stimulation (SCS) has been a significant addition to the available options, it is often inadequate in relieving both the back and leg pain components. We hypothesized that for some patients the combination of SCS with peripheral nerve field stimulation (PNFS) would be a safe, effective alternative that would be more effective than either modality alone. Objective. Our objective was to demonstrate the efficacy of PNFS used in combination with SCS for the treatment of chronic pain syndromes involving the lower back and legs. Study Design. Case series. Methods. A total of 20 patients with chronic low back and leg pain syndromes who had failed conventional therapies underwent implantation of a combination of traditional SCS and PNFS. Leads were placed in the epidural space, as well as superficially in the subcutaneous tissues of the lower back, directly in the region of maximum pain. Patients initially underwent a trial of stimulation to assess response, and a permanent system was implanted if patients reported greater than 50% pain relief during the trial. For some patients, a combination was used at the time of the initial trial. In other cases, the decision to proceed with the combination was made later, either at the time of permanent implant, or later on, after SCS alone failed to adequately control pain. Results. In each case, PNFS was used in combination with traditional SCS for patients with chronic lower back and lower extremity pain. While not all of these patients ultimately proceeded with the combination of SCS and PNFS to control their pain, the majority of patients found the combination better in controlling their overall pain than either modality alone. In addition, using a combined approach at the time of trial provided a noninvasive and effective method of comparing the efficacy of each method, allowing patients to identify the best form of neuromodulation for their particular pain. Conclusions. Due to the availability of 16 contact capacity generators, neurostimulation with multiple leads in various combinations—including both epidural and peripheral nerve field stimulation simultaneously—can be applied safely and effectively. The availability of this combined approach for a trial of stimulation prior to implant allows patients to compare SCS to PNFS and to indicate a preference for one over the other or for the combination. We conclude that PNFS may be used in combination with SCS as a safe and effective alternative treatment for patients with chronic low back and leg pain, and further suggest that the combined approach should be considered as a treatment option for this population.     

Anterograde Revision of Cervical Spinal Cord Stimulator Paddle Electrode: A Case Report

Objectives: To illustrate a new surgical revision strategy for malfunctioning spinal cord stimulation (SCS) paddle electrodes. Background: SCS is a treatment for chronic neuropathic pain that delivers therapeutic doses of electric current to the dorsal columns resulting in dermatomal paresthesia and pain reduction. Reasons for SCS failure include hardware malfunction or breakage and medical complications. Case Report: A 34‐year‐old woman presented with a two‐year history of intractable pain in the left upper extremity and thoracic region which was previously controlled by SCS. Imaging demonstrated breakage of the cervical electrode wire that had been advanced in the caudal direction from the C1 spinal level. Revision of the broken electrode was performed by hemilaminectomy of C3‐C4 and the replacement electrode was advanced in the cephalad direction. Results: Ideal and exact paresthesia pattern was confirmed intraoperatively and the patient maintained successful pain reduction at five‐year follow‐up. Conclusion: Advancing SCS electrodes into the upper cervical spine in the cephalad direction, using the previously formed scar capsule, offers an alternate strategy for revision of malfunctioning SCS paddle electrodes.     

Multiple Lead Spinal Cord Stimulation for Chronic Mechanical Low Back Pain: A Comparative Study with Intrathecal Opioid Drug Delivery

The objective of this paper is to assess the outcome of implanted multiple thoracolumbar lead spinal cord stimulation (SCS) in mechanical back pain without prior spinal surgery. These results are compared with intrathecal opioid drug delivery (ITDD). An anonymous third party patient questionnaire study of pain relief, function and psychosocial quality of life measures (recorded on 11‐point numerical rating scales) for 12 patients with SCS and 13 with ITDD was used. Pain was significantly reduced with multiple lead SCS from a median of 9.0–6.5 (p < 0.01) and with ITDD from a median of 8.5–5.5 (p < 0.01). There was a trend towards greater reduction in pain in the ITDD group compared with the SCS group (pain differences 4.5 and 2.6, respectively) but this did not reach statistical significance. The majority of psychosocial quality of life measures were significantly more improved in the ITDD group compared with the SCS group (p < 0.05). We conclude that multiple‐lead SCS improves mechanical back pain in patients unresponsive to more conservative measures. However, ITDD provides significantly more improved quality of life measures, with a trend towards greater pain reduction than SCS.     

Imaging features in Hirayama disease

Purpose: To evaluate the MR findings in clinically suspected cases of Hirayama disease. Materials and Methods: The pre and post contrast neutral and flexion position cervical MR images of eight patients of clinically suspected Hirayama disease were evaluated for the following findings: localized lower cervical cord atrophy, asymmetric cord flattening, abnormal cervical curvature, loss of attachment between the posterior dural sac and subjacent lamina, anterior shifting of the posterior wall of the cervical dural canal and enhancing epidural component with flow voids. The distribution of the above features in our patient population was noted and correlated with their clinical presentation and electromyography findings. Observations: Although lower cervical cord atrophy was noted in all eight cases of suspected Hirayama disease, the rest of the findings were variably distributed with asymmetric cord flattening, abnormal cervical curvature, anterior shifting of the posterior wall of the cervical dural canal and enhancing epidural component seen in six out of eight (75%) cases. An additional finding of thoracic extension of the enhancing epidural component was also noted in five out of eight cases. Conclusion: Dynamic post contrast MRI evaluation of cervicothoracic spine is an accurate method for the diagnosis of Hirayama disease.     

Electrophysiologic Monitoring for Placement of Laminectomy Leads for Spinal Cord Stimulation Under General Anesthesia

Objectives: Spinal cord stimulation (SCS) is a valid option for intractable neuropathic pain syndromes, yet some patients cannot undergo the standard awake procedure. Our retrospective study chronicles laminectomy‐electrode placement for SCS under general anesthesia and use of compound muscle action potentials (CMAPs) to guide placement in the absence of patient verbal feedback. Methods: After nonsurgical measures proved ineffective for relief of neuropathic pain, 8 men and 11 women underwent SCS lead placement under general rather than local anesthesia because of deafness, language barriers, lidocaine allergy, or extensive scar tissue. A midline thoracic laminectomy was performed, and paddle SCS leads were placed. CMAPs of the rectus abdominis, quadriceps, gastrocnemius, anterior tibialis, abductor hallicus, and intercostal muscles were analyzed. Final lead placement was determined by the right‐to‐left symmetry of the CMAPs in conjunction with fluoroscopic imaging. Stimulation coverage was evaluated postoperatively. Results: Inconsistencies were found in lower‐extremity CMAPs in the first two procedures. Thereafter, intercostal and rectus abdominis muscle CMAPs obtained in the remaining 17 procedures were consistent, more predictive of final results. Immediately postoperatively, 16 (84.2%) of 19 patients had adequate stimulation coverage and good pain relief with appropriate programming. Of three (15.8%) patients with minimal or no short‐term pain relief, lack of response was not attributable to inadequate distribution of stimulation. Conclusions: With electrophysiologic monitoring and fluoroscopy guidance, placement of SCS laminectomy leads in select patients under general anesthesia may result in appropriate stimulation coverage and pain relief in most.