Spinal Cord Stimulation Lead Research Articles

S1-3. Spinal cord stimulation in Parkinson disease

The new devices introduced for spinal cord stimulation (SCS) enable us to choose stimulation contacts and to change the stimulation conditions even after implantation. SCS is used for treating chronic pain that is resistant to medication. Many patients with Parkinson disease (PD) develop pain as a non-motor manifestation. SCS lead to gait improvement in our 5 patients with PD-related pain. The mechanism underlying the SCS-induced improvement in Parkinsonian gait is not known. Gait is thought to be controlled by mainly 3 regions, the midbrain locomotion region, brain stem locomotion region, which is the pedunculopontine nucleus in humans, and spinal central pattern generator (CPG). Dimitrijevic et al. showed locomotion-like reciprocal electromyogram bursts for the lower legs of patients with complete spinal cord injury; this suggests that the CPG is important for gait improvement (Ann N Y Acad Sci. 1998 Nov). Epidural SCS-induced locomotion in mouse and rat models of PD; the induction of locomotion was more pronounced when l-dopa was administered along with SCS, indicating that the central mechanisms play a role in locomotion induction (Fuentes et al., Science 20 March 2009). Further studies are required to elucidate the mechanism of SCS-induced gait improvement in patients with PD.

S1-1. Spinal cord stimulation for post-stroke pain

Spinal cord stimulation (SCS) is used to treat for several types of intractable pain syndromes, but it is not commonly used for treating post-stroke pain. Therefore, in this study, we analyzed the effects of SCS in patients with post-stroke pain. Neurological imaging and pharmacological analysis using thiopental, ketamine and morphine tests were conducted for 30 patients with post-stroke pain. For all patients, percutaneous electrodes were inserted under local anesthesia, and trial stimulation was performed for 5–7 days. If the patient experienced pain relief during the trial stimulation, a pulse generator was implanted. Of the 30 patients, 26 (87%) experienced satisfactory pain relief and underwent implantation. Ten patients received dual-octad lead SCS. The stimulation induced adequate paresthesia in all 10 patients. Nine (90%) of the 10 patients experienced satisfactory pain relief and opted for pulse generator implantation in order to proceed with the treatment. Upper cervical SCS was performed for patients with pain in not only the upper and lower extremities but also the face. Upper cervical SCS provided good paresthesia coverage and was effective for such patients. We think that patients with post-stroke pain may respond favorably to dual-octad lead SCS, and advancements in devices for SCS would further improve treatment outcomes for such patients.

Predictors of Pain Relief Following Spinal Cord Stimulation in Chronic Back and Leg Pain and Failed Back Surgery Syndrome: A Systematic Review and Meta‐Regression Analysis

We sought to assess the extent to which pain relief in chronic back and leg pain (CBLP) following spinal cord stimulation (SCS) is influenced by patient-related factors, including pain location, and technology factors. A number of electronic databases were searched with citation searching of included papers and recent systematic reviews. All study designs were included. The primary outcome was pain relief following SCS, we also sought pain score (pre- and post-SCS). Multiple predictive factors were examined: location of pain, history of back surgery, initial level of pain, litigation/worker's compensation, age, gender, duration of pain, duration of follow-up, publication year, continent of data collection, study design, quality score, method of SCS lead implant, and type of SCS lead. Between-study association in predictive factors and pain relief were assessed by meta-regression. Seventy-four studies (N = 3,025 patients with CBLP) met the inclusion criteria; 63 reported data to allow inclusion in a quantitative analysis. Evidence of substantial statistical heterogeneity (P < 0.0001) in level of pain relief following SCS was noted. The mean level of pain relief across studies was 58% (95% CI: 53% to 64%, random effects) at an average follow-up of 24 months. Multivariable meta-regression analysis showed no predictive patient or technology factors. SCS was effective in reducing pain irrespective of the location of CBLP. This review supports SCS as an effective pain relieving treatment for CBLP with predominant leg pain with or without a prior history of back surgery. Randomized controlled trials need to confirm the effectiveness and cost-effectiveness of SCS in the CLBP population with predominant low back pain.

Spinal Cord Stimulation for Radicular Pain Following Retained Bullet in the Spinal Canal

We are reporting on the implantation of a spinal cord stimulator to treat intractable radicular pain following a retained bullet fragment in the spinal canal. Such retained fragments are associated with risks including pain, neurological deficit, infection, toxic effects, and migration. Our patient was a young man with radicular pain and history of a gunshot entering the abdomen. Computed tomography of the spine had revealed a nearly complete bullet in the right paracentral canal at L4, partially extending into the lateral recess. He presented 17 months after his injury with gradually worsening pain and parasthesias radiating from the back to the whole right leg and foot. There was no weakness. As the patient had failed conservative therapy, procedural options were considered. In this case, the potential benefits of epidural steroid injection by any approach might not have outweighed risks of infection, related to foreign body and local steroid, or possible migration due to mechanical forces during injection. As he may well need repeated epidural steroid injections to manage his pain, this increases his risk for infection. A percutaneous trial spinal cord stimulation lead was placed, with epidural entry well away from the bullet. After good results, a permanent system was implanted. There was no evidence of infection or migration, and excellent pain relief was achieved. Bullets and other foreign bodies retained in the spinal canal can cause progressive neurologic symptoms through reactive tissue formation and compression. Spinal cord stimulation can relieve radicular pain while avoiding risks associated with altering the location of the offending foreign body. Key words: Spinal cord stimulation, radicular pain, retained bullet, gunshot wound, spinal canal, spinal injury, lumbar spine

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

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. 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. 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. 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.

Effect of a Novel Fixation Method for Spinal Cord Stimulators

Spinal cord stimulation is a well-established treatment for recalcitrant pain syndromes such as failed back surgery syndrome. Techniques minimizing surgical time and incision size and increasing lead stability are of great value to both the patient and implanting physician. We present a consecutive case series review of ten permanent percutaneous spinal cord implants utilizing a novel lead fixation device. The purpose of this case series review is to present initial findings of the minimized incision size and thoughts surrounding the new device and technique. Ten cases were performed utilizing the new device (fiXate) and technique. Incision size was dictated by adequate visualization of the fascial stratum as well as technical working space required for lead fixation and redirection to the generator pocket. Each spinal cord stimulator lead was affixed to the thoracodorsal fascia utilizing the novel device. In this consecutive series, the average midline incision size was 2.2 cm (range = 1.9-2.6 cm) which is greatly minimized through the use of the device. Not only may fiXate directly affect incision size, operating room and anesthesia time may also be lessened due to the semiautomated nature of the device. Of the cases performed, there were no complications or adverse events. Of note, there have been no reports of lead migrations during this case series, the average follow-up time being 18 weeks (range 11-26 weeks). These data suggest a new method of fixation can be utilized for percutaneous spinal cord stimulation that allows a reduction in incision size. Intuitively, reduction in incision size is relevant with regard to tissue morbidity and may also have implications with regard to infection. Use of the device may also reduce operating room and anesthesia time as well as provide greater stability than standard suture.

Delayed Onset of Epidural Haematoma by Spinal Cord Stimulator Lead Migration and its Spontaneous Resolution

Delayed Onset of Epidural Haematoma by Spinal Cord Stimulator Lead Migration and its Spontaneous Resolution

Cephalad Lead Migration Following Spinal Cord Stimulation Implantation

Lead migration (LM) is the most common complication after spinal cord stimulation (SCS). Although multiple reports of caudad LM have been described, cephalad LM has not been reported. Here we describe a case in which a stimulator lead migrates in the cephalad direction. A 60-year-old male with failed back surgery syndrome underwent SCS lead implantation via a dual lead approach to the top of vertebral body (VB) T9. A standard strain relief loop was used for each lead in the paramedian pocket. Postoperative testing revealed 100% paresthesia coverage of the painful areas. For the first 4 days, the patient continued to have excellent coverage; however, by the seventh day, the paresthesias ascended to above the nipple line. At the 2-week follow-up, cephalad migration of the left lead to the top of VB T1 was confirmed on fluoroscopy. The patient underwent successful lead revision in which a single paramedian incision technique was used to place extra sutures and a “figure-of-eight” strain relief loop. We provide the first case report of significant cephalad LM following SCS lead implantation. This migration can occur despite the use of current standard anchoring techniques. Additional investigation into the mechanism of such LM and lead-securing techniques is warranted. Key words: spinal cord stimulation, lead migration, lead revision, strain relief loop

Topographical Anatomical Neuropathic-Pain Guided (TANG) Mapping: A Tool Derived from a Patient Perspective to Facilitate the Transition from Spinal Cord Stimulator Trial to Potential Permanent Implantation

Introduction: Collecting a patient’s pain scores and the analgesic effect achieved during spinal cord stimulation (SCS) trials can be difficult, and no standard exists for doing so. We propose a topographical mapping tool that was derived from a patient’s perspective. Case: A 60-year-old man with postherpetic neuralgia (PHN) underwent a SCS trial after conservative treatment failed to relieve his pain. During the SCS trial, with the SCS off and on in five different settings, he recorded pain levels in each of the six different painful zones he identified. The data collected were transferred to a topographical and anatomical map, which helped the physicians to better understand the effects of the SCS at different settings. Ultimately, the data collected by the patient helped the physicians to implant a permanent SCS successfully. Conclusions: Patient pain diaries have been used in pain medicine for years. This particular patient’s collection of pain scores and SCS effects inspired the construction of a more standardized tool for collecting such data during SCS trials. We propose that use of our Topographical Anatomical Neuropathic-pain Guided (TANG) mapping tool will enable physicians to choose SCS lead positions more precisely than is currently possible.

Spinal Cord Stimulation for Visceral Pain From Chronic Pancreatitis

Spinal cord stimulation (SCS) may reduce pain scores and improve function in patients with various chronic abdominal pain syndromes including chronic pancreatitis. Here described is a large clinical experience in SCS for severe chronic pancreatitis. SCS was trialed in 30 patients with chronic pancreatitis. SCS trials lasted 7-14 days (median 9 days). SCS lead tips were mostly positioned at the T5 (N= 10) or T6 (N= 10) vertebral level. Twenty-four patients (80%) reported at least 50% pain relief on completion of the trial. Among these, pre-trial visual analog scale (VAS) pain scores averaged 8 ± 1.6 (standard deviation) and opioid use averaged 165 ± 120 mg morphine sulfate equivalents. During the trial, VAS pain scores decreased to 3.67 ± 2 cm (p < 0.001, Mann-Whitney Rank Sum Test) and opioid use decreased to 105 ± 101 mg morphine equivalent a day. Six patients failed the trial; one was lost to follow-up; in three patients after the implantation, the system had to be removed due to infection or lead migration; and 20 were followed for the whole year. For 20 patients followed for the whole year, VAS pain scores remained low (3.6 ± 2 cm; p < 0.001) at one year, as did opioid use (48.6 ± 58 mg morphine equivalents). SCS may be a useful therapeutic option for patients with severe visceral pain from chronic pancreatitis. Prospective trial is warranted.

Back Pain: A Real Target for Spinal Cord Stimulation?

Failed back surgery syndrome represents one of the most frequent etiologies of chronic back pain and is a major public health issue. Neurostimulation has currently not been validated in the treatment of back pain because of technological limitations in implantable spinal cord stimulation (SCS) systems. New-generation leads using several columns of stimulation can generate longitudinal and/or transverse stimulation fields into the spinal cord. To investigate, through extensive stimulation testing, the capacity of multicolumn tripolar leads to achieve back territory paresthesia coverage in refractory failed back surgery syndrome patients. Eleven patients implanted with a 16-contact spinal cord stimulation lead (Specify 5-6-5, Medtronic Inc) were assessed with a systematic exploration of 43 selected stimulation configurations to generate bilateral back paresthesia in addition to leg territory coverage. The tripolar lead successfully generated paresthesia in both bilateral back and leg territories in 9 patients (81.8%). Success rates of multicolumn stimulation patterns were significantly higher than for longitudinal configurations for lombodorsal paresthesia coverage. Six months after implantation, significant pain relief was obtained compared with preoperative evaluation for global pain (Visual Analog Scale, 2.25 vs 8.2 preoperatively; P < .05), leg pain (Visual Analog Scale, 0.5 vs 7.6 preoperatively; P < .05), and back pain (Visual Analog Scale, 1.5 vs 7.8 preoperatively; P < .05). These results suggest that multicolumn leads can reliably generate back pain coverage and favor pain relief outcomes. This may lead physicians to reconsider new indications for spinal cord stimulation. Expanding neurostimulation perspectives to intractable back pain syndromes could become realistic in the near future.

Spinal Cord Stimulation in a Patient with Spinal Epidural Lipomatosis

Spinal cord stimulation is the most commonly used implantable neurostimulation modality for management of pain syndromes. For treatment of lower extremity pain, the spinal cord stimulator lead is typically placed in the thoracic epidural space, at the T10-T12 levels. Typically, satisfactory stimulation can be obtained relatively easily. Anatomical variability in the epidural space, such as epidural scarring, has been reported to prevent successful implantation of spinal cord stimulators. Spinal epidural lipomatosis describes an abnormal overgrowth of adipose tissue in the extradural space. Cases have documented spinal epidural lipomatosis complicating intrathecal baclofen pump implantation or causing repeated failure of epidural analgesia. However, so far, there is no published literature describing how spinal epidural lipomatosis affects spinal cord stimulation. We report a case of spinal cord stimulation in a patient with spinal epidural lipomatosis. Very high impedance was encountered during the trial spinal cord stimulator lead placement. Satisfactory stimulation was only obtained after repeated repositioning of the spinal cord stimulator trial lead. Post-procedure thoracic spine magnetic resonance imaging revealed marked thoracic epidural lipomatosis. At the level where satisfactory stimulation was obtained, the thickness of the epidural fat was within normal limits. The patient eventually underwent placement of a laminotomy lead with good coverage and pain relief. Spinal epidural lipomatosis significantly increases the impedance in the epidural space, making effective neurostimulation very difficult to obtain. Physicians should consider the possibility of spinal epidural lipomatosis when very high impedances are encountered during lead placement.

Impact to Spinal Cord Stimulator Lead Integrity with Direct Suture Loop Ties: Commentary on Kreis et al. (2009)

Dear Dr. Paul G. Kreis et al., I read with great interest your article “Impact to Spinal Cord Stimulator Lead Integrity with Direct Suture Loop Ties” [1]. It is acknowledged that current anchoring devices suffer from unpredictable lead retention, possible lead fracture, and discomfort due to being bulky. As an alternate to existing anchors, this study examined a direct suture fixation technique. This study clearly shows no gross lead damage using this technique in the short term. These results are preliminary as spelled out in the report. However, this study raises many important issues regarding the direct suturing of spinal cord stimulator leads. It is now common practice for stimulation leads to be manufactured with outer polyurethane …

Spinal Cord Stimulation for Chronic Visceral Abdominal Pain

Spinal cord stimulation (SCS) may reduce pain scores and improve function in patients with chronic visceral abdominal pain. We thus present our large clinical experience in SCS for visceral abdominal pain. We trialed spinal cord stimulation in 35 patients, each of whom was shown by retrograde differential epidural block to have either visceral pain (n = 32) or mixed visceral and central pain (n = 3). SCS trials lasted 4 to 14 days (median 9 days). SCS lead tips were mostly positioned at T5 (n = 11) or T6 (n = 10). Thirty patients (86%) reported at least 50% pain relief upon completion of the trial. Among these, pretrial visual analog scale (VAS) pain scores averaged 8.2 +/- 1.6 (SD) and opioid use averaged 110 +/- 119 mg morphine sulfate equivalents. During the trial, VAS pain scores decreased to 3.1 +/- 1.6 cm (P < 0.001, Mann-Whitney Rank Sum Test) and opioid use decreased to 70 +/- 68 mg morphine equivalent a day (P = 0.212). Five patients failed the trial, one was lost to follow-up, and 19 were followed for the whole year. Seven patients were either followed for less than a year (n = 3) or the SCS system was removed due to infection or lead migration (n = 4). One patient despite the successful trial felt no improvements at 6 months after the implant and requested an explant of the SCS device. Among the 28 patients who received permanent implant, 19 were followed at least a year. Their VAS pain scores remained low (3.8 +/- 1.9 cm; P < 0.001) at 1 year, as did opioid use (38 +/- 48 mg morphine equivalents; P = 0.089). Spinal cord stimulation may be a useful therapeutic option for patients with severe visceral pain.

Impact to Spinal Cord Stimulator Lead Integrity with Direct Suture Loop Ties

Lead migration of spinal cord stimulators (SCS) is a significant problem, and experience suggests that anchoring sutures directly around the SCS lead may reduce migration. Such practices have been limited by concerns about potential damage to the lead and impairment of performance. This study sought to determine the extent of overt damage following maximal tension from tying sutures directly around SCS leads. Twenty-eight SCS leads were prospectively exposed to 56 suture knots that were tightened under controlled conditions to the suture's breaking point. Lead damage was evaluated by high power microscopy and assessment of lead impedance. None of the leads had evidence of substantial physical damage or electrical impairment. This small study suggests that anchoring directly to the lead appears to produce minimal damage, but these preliminary data must be confirmed and expanded.

Efficacy of a Single, Percutaneous, Across Midline, Octrode® Lead Using a “Midline Anchoring” Technique in the Treatment of Chronic Low Back and/or Lower Extremity Pain: A Retrospective Study

Introduction. Spinal cord stimulation is a widely used treatment modality for chronic pain, especially failed back surgery syndrome. However, migration of the lead or leads, coverage of axial pain, and the selection of an optimal system configuration continue to be subjects for serious debate. Materials and Methods. A retrospective study of the use of the method of "midline anchoring" of a single Octrode® lead, in 54 patients with low back and/or lower extremity pain, was done to assess the efficacy of this technique. Results. During the study period of 9.3months, only a 4% revision rate was reported. Reduction in pain of more than 50% and individual patient satisfaction scores were very high (85% and 87%, respectively). Successful bilateral pain coverage was obtained with a single Octrode® lead. The lower extremities and buttocks area were captured in 89% of the patients. Axial pain coverage was achieved in the majority of the patients, with 71% reporting adequate coverage of the upper lumbar spine. A "guarded cathode" array was used in the vast majority of the cases, with a relatively low position of the lead. Conclusions. "Midline anchoring" of the spinal cord stimulation lead is an effective implantation technique, allowing the use of a single, percutaneous, Octrode® lead, while preventing lead migration and allowing capture of axial and lower extremity pain, unilateral as well as bilateral. This study revives the idea of a single lead as a possible optimal configuration.

Subdural Hematoma Following Spinal Cord Stimulator Implant

Headache following interventional procedures is a diagnostic challenge due to the multitude of possible etiologies involved. Presentation can be simple (PDPH alone) or complex (exacerbation of pre-existing chronic headache along with PDPH) or headache associated with a new onset intracranial process. Subdural hematoma is a rare complication of cranio-spinal trauma. Cranial subdural hematoma may present in an acute, sub-acute, or chronic fashion. Diagnosis of a subdural hematoma in the wake of a PDPH is difficult, requiring a high level of suspicion. Delayed diagnosis of subdural hematoma is usually related to failure to consider it in the differential diagnosis. Thorough history, assessment of the evolution of symptoms, and imaging studies may identify the possible cause and help direct treatment. Change in the character of initial presenting symptoms may be a sign of resolution of the headache or the onset of a secondary process. We report a case of acute intracranial subdural hematoma secondary to unintentional dural puncture during placement of a permanent spinal cord stimulator lead for refractory angina. There is need for careful follow-up of patients with a known post-dural tear. Failure to identify uncommon adverse events in patients with complicated spinal cord stimulator implantation may lead to permanent injury.

Author Response to: Request for Additional Pertinent Information Regarding 4 Extremity Stimulation Coverage from C2 Spinal Cord Stimulation Lead Placement

Author Response to: Request for Additional Pertinent Information Regarding 4 Extremity Stimulation Coverage from C2 Spinal Cord Stimulation Lead Placement

Request for Additional Pertinent Information Regarding 4 Extremity Stimulation Coverage from C2 Spinal Cord Stimulation Lead Placement

Request for Additional Pertinent Information Regarding 4 Extremity Stimulation Coverage from C2 Spinal Cord Stimulation Lead Placement

Effects of Electrode Positioning on Perception Threshold and Paresthesia Coverage in Spinal Cord Stimulation

Objectives. This pilot study aims to validate the hypothesis that a smaller distance between spinal cord stimulation (SCS) lead and spinal cord results in more extensive paresthesia and less energy consumption. Materials and Methods. After insertion of a percutaneous SCS lead in patients with chronic pain (condition A), a first catheter was temporarily placed alongside the lead (condition B), and a second catheter was placed on the other side of the lead (condition C). In all three conditions paresthesia coverage, perception threshold (PT) of paresthesia, and maximum comfortable (MC) stimulus amplitude were determined and the catheters were subsequently removed. Results. Paresthesia coverage in all six patients was increased markedly in condition C when compared to condition A, whereas the mean values of PT, MC, and therapeutic range (MC/PT) dropped by 22%, 14%, and 13%, respectively. Conclusions. The results suggest that paresthesia coverage is increased when the space between the SCS lead and spinal cord gets smaller, whereas PT and energy consumption are reduced.