Stimulator Paddle Research Articles

ID: 332465 A Prospective Evaluation of Selectivity in a High-Resolution Spinal Cord Stimulation Paddle

ID: 332465 A Prospective Evaluation of Selectivity in a High-Resolution Spinal Cord Stimulation Paddle

ID: 330220 Follow My Lead: Migration of Spinal Cord Stimulator Paddle

ID: 330220 Follow My Lead: Migration of Spinal Cord Stimulator Paddle

Spinal Cord Stimulator Paddle Lead Revision and Replacement for Misplaced or Displaced Electrodes

ObjectivesSpinal cord stimulators (SCS) are commonly implanted via a laminotomy or laminectomy. Revision surgery may be necessary in instances of hardware failure or loss of efficacy. It is uncommon for leads to have been initially misplaced in a suboptimal position, and revision in these cases necessitates additional dissection for appropriate repositioning. Accordingly, there is concern with a more extensive revision for a potentially higher risk of associated complications. This study aims to describe a series of patients with failed paddle SCS electrodes due to misplacement who underwent revision and replacement. MethodsPatients who underwent SCS paddle replacement for misplaced paddles between 2021 and 2023 were identified. Medical charts were reviewed for demographic data, operative details, and incidence of complications. ResultsSixteen patients underwent thoracic SCS paddle revision and replacement. The mean age was 59.6±12.6 years, with 11 females and 5 males. Misplaced paddles were too lateral (n=12), too high (n=2), or incompletely within the epidural space (n=2). The mean duration from initial implantation to revision surgery was 44.8±47.5 months. The mean operative duration was 126.1±26.9 minutes, and all patients required a “skip” laminectomy or laminotomy. No complications were encountered. The mean length of follow-up was 18.4±7.3 months. Mean preoperative pain intensity was 7.9±1.5, and at last follow-up was 3.6±1.7 (p<0.001). All but one patient continued to use their device in follow-up. ConclusionThe revision and replacement of misplaced paddle SCS electrodes is a feasible and durable revision strategy, even in long-term implants with extensive scarring.

Interlaminar endoscopic uniportal approach for implantation of a paddle lead larger than 10 mm for spinal cord stimulation: illustrative case.

The authors aim to describe a new technique for implantation of a spinal cord stimulation paddle lead sized over 10 mm through an endoscopic uniportal approach. A new endoscopic cannula was developed for the passage of a paddle lead width between 10 and 13 mm. The distal portion of the cannula was designed with a larger opening, providing better visibility of the anterior portion of the adjacent structures, thus allowing a panoramic view of the electrode passage. An electrode was implanted in an 11-mm paddle. After searching PubMed, Cochrane, and Lilacs databases, the authors found no mention of the implantation of a paddle electrode with a width greater than 10 mm. The implantation of a paddle electrode less than 10 mm wide is possible via endoscopic access using 10-mm working channels. However, for electrodes with a width greater than 10 mm, access via endoscopy is impossible, since the working channel is only 10 mm. The authors concluded that it is possible to pass electrodes safely and effectively with a paddle width between 10 and 13 mm using spinal endoscopy via uniportal interlaminar access. However, it is necessary to expand studies to elucidate this technique of endoscopic implantation of electrodes for neurostimulation.

Analysis of spinal canal diameter in the placement of thoracic spinal cord stimulator paddle leads.

Neurologic deficit is known as a rare complication of thoracic spinal cord stimulator (SCS) paddle lead implantation, but many believe its incidence after SCS paddle lead placement is under-reported. It is possible that imaging characteristics may be used to help predict safe paddle lead placement. This imaging study was undertaken to determine the minimum canal diameter required for safe paddle lead placement. Patients who underwent thoracic laminotomy for new SCS paddle lead placement from January 2018 to March 2023 were identified retrospectively. Preoperative thoracic canal diameter was measured in the sagittal plane perpendicular to the disc space from T5/6 to T11/12. These thoracic levels were chosen because they span the most common levels targeted for SCS placement. Patients with and without new neurologic deficits were compared using a Mann-Whitney U-test. Of 185 patients initially identified, 180 had thoracic imaging available for review. One (0.5%) and 2 (1.1%) of 185 patients complained of permanent and transient neurologic deficit after thoracic SCS placement, respectively. Patients with neurologic deficits had average canal diameters of <11 mm. The average canal diameter of patients with and without neurologic deficits was 10.2 mm (range 6.1-12.9 mm) and 13.0 mm (range 5.9-20.2), respectively (p < 0.0001). Postoperative neurologic deficit is an uncommon complication after thoracic laminotomy for SCS paddle lead placement. The authors recommend ensuring a starting thoracic canal diameter of at least 12 mm to accommodate a SCS paddle lead measuring 2 mm thick to ensure a final diameter of >10 mm. If canal diameter is <12 mm, aggressive undercutting of the lamina, a second laminotomy, or placement of smaller SCS wire leads should be considered.

Animal Feasibility Study of a Novel Spinal Cord Stimulation Multicolumn Lead (Heron Lead).

Currently available spinal cord stimulation paddle leads require a laminectomy, limiting the types of clinicians who can implant and increasing the risk of complications. Recently, WISE S.r.l. designed a prototype multicolumn lead named the Heron® lead that can be implanted percutaneously. The purpose of the study was to examine the efficiency of placing a paddle lead percutaneously. Ten sheep were assigned to either the Heron lead group (n = 7) or the control group (n = 3). The sheep were observed for 13 weeks after implantation. Neurological and clinical examinations were conducted prior to surgery and then during the follow-up period. The implantation sites were evaluated through macroscopic observations during the article explantation and the lead migration was evaluated by comparing the article positioning at the surgery, four weeks after the surgery and at the explantation day through fluoroscope images. A qualitative comparison was made between the results collected with the test article and the control article. Observations at the surgical sites indicate that test animals appeared to have less swelling around the surgical wound than control ones in the first 14 days, but no impact on wound healing was noticed. Additionally, no clear difference was observed in pain scores between the two groups, with observations tending to show that the maximum pain was occurring later in the test group with respect to the control group. General clinical observations showed no major difference between the two groups, and determined clinical abnormalities were not directly related to the procedure. Lastly, neurological deficits frequency decreased from the first to last animal operated, regardless of their test or control status. Our study concluded that the Heron lead is safe to implant, with a safety profile similar to the control article. Additionally, we conclude that the Heron lead is effective in reducing lead migration events.

Neuroanatomical mapping of the lumbosacral spinal cord in individuals with chronic spinal cord injury.

With emerging applications of spinal cord electrical stimulation in restoring autonomic and motor function after spinal cord injury, understanding the neuroanatomical substrates of the human spinal cord after spinal cord injury using neuroimaging techniques can play a critical role in optimizing the outcomes of these stimulation-based interventions. In this study, we have introduced a neuroimaging acquisition and analysis protocol of the spinal cord in order to identify: (i) spinal cord levels at the lumbosacral enlargement using nerve root tracing; (ii) variability in the neuroanatomical characteristics of the spinal cord among individuals; (iii) location of the epidural stimulation paddle electrode and contacts with respect to the spinal cord levels at lumbosacral enlargement; and (iv) the links between the anatomical levels of stimulation and the corresponding neurophysiological motor responses. Twelve individuals with chronic, motor complete spinal cord injury implanted with a spinal cord epidural stimulator were included in the study (age: 34 ± 10.9 years, sex: 10 males, 2 females, time since injury: 8.2 ± 9.9 years, American Spinal Injury Association Impairment Scale: 6 A, 6 B). High-resolution MRI scans of the spinal cord were recorded pre-implant. An analysis of neuroanatomical substrates indicates that the length of the spinal column and spinal cord, location of the conus tip and the relationship between the spinal cord levels and vertebral levels, particularly at the lumbosacral enlargement, are variable across individuals. There is no statistically significant correlation between the length of the spinal column and the length of the spinal cord. The percentage of volumetric coverage of the lumbosacral spinal cord by the epidural stimulation paddle electrode ranges from 33.4 to 90.4% across participants. The location of the spinal cord levels with respect to the electrode contacts varies across individuals and impacts the recruitment patterns of neurophysiological responses. Finally, MRI-based spinal cord modelling can be used as a guide for the prediction and preplanning of optimum epidural stimulation paddle placement prior to the implant surgery to ensure maximizing functional outcomes. These findings highlight the crucial role that the neuroanatomical characteristics of the spinal cord specific to each individual play in achieving maximum functional benefits with spinal cord electrical stimulation.

Techniques for Safe Removal of Spinal Cord Stimulation Paddle Leads.

Spinal cord stimulation (SCS) is a safe neuromodulatory treatment used to treat failed back surgery syndrome, chronic neuropathic pain, and complex regional pain syndrome. Despite its efficacy, some patients fail to achieve pain relief and elect to undergo removal of SCS paddle leads. The safety and best practices of these procedures have not been defined. In this article, we describe our technique and complication rate in a series of SCS paddle removals. All patients who underwent SCS paddle removal at the Albany Medical Center between 2011 and 2020 were identified. Medical charts were reviewed for demographic data, operative technique, and incidence of complications within 30 days of the procedure. Thirty-two (91%) patients underwent a thoracic paddle removal, whereas 3 (9%) underwent a cervical paddle removal. All cases underwent preoperative imaging with computed tomography or MRI, and all cases were performed with neuromonitoring and fluoroscopy. The technique required for paddle removal depended on the extent of local scar formation and ranged from soft tissue dissection to additional laminectomy at an adjacent level. Cases took on average 2 ± 0.09 hours with 23.21 ± 4.29 cc blood loss. Two patients had superficial infections, which were cleared with 1 week of oral antibiotics. There were no other adverse events. Thirty-five patients successfully underwent paddle removal with the minor complications reported. In this article, we show that by using neuromonitoring, fluoroscopy, and the techniques described, SCS paddle removal can be performed with minimal risk.

High-Resolution Spinal Motor Mapping Using Thoracic Spinal Cord Stimulation in Patients With Chronic Pain.

High-resolution spinal cord stimulation (HR-SCS) paddle can stimulate medial-dorsal columns and extend stimulation coverage to the laterally positioned spinal targets. To investigate the medio-lateral selectivity of an HR-SCS paddle in patients with chronic pain. During standard-of-care spinal cord stimulation (SCS) placement, epidurally evoked electromyography and antidromic dorsal column-evoked potentials were recorded in 12 subjects using an HR-SCS paddle with 8 medio-lateral sites spanning the full epidural width at thoracic T9-12 and a commercial paddle consecutively. Recruitment maps were aligned with respect to physiological midline which was overlapping with anatomic midline in 10 of 11 cases. Overlapping contacts between the HR-SCS and commercial paddles exhibited similar patterns while HR-SCS demonstrated higher precision targeting of certain dermatomes. Spinal motor maps showed that the lateral contacts triggered stronger responses in medial gastrocnemius, adductor magnus, and tibialis anterior while the medial contacts triggered stronger responses in gluteus maximus and adductor hallucis. The time-locked popliteal fossa responses indicated ipsilateral activation by HR-SCS at the lateral contacts and bilateral activation at the medial contacts with stronger ipsilateral responses. This study is the first to perform high-resolution medio-lateral SCS mapping in patients with chronic pain. These results show promise that HR-SCS may provide additional ipsilateral recruitment within the extremities which improve targeting of focal pain in the lower extremities. Furthermore, this study supports the functional use of intraoperative neuromonitoring as a decision tool to determine physiological midline in thoracic SCS surgeries and provides a full methodological framework.

Revision and Replacement of Spinal Cord Stimulator Paddle Leads

ObjectivesPaddle leads for spinal cord stimulation (SCS) offer more efficient energy delivery and advantages in some patients. However, there is concern for how safely SCS paddles can be replaced once previously implanted because of scar tissue and the relative vulnerability of the thoracic cord. In this study, we share our experience on SCS paddle replacement. Materials and MethodsParticipants who underwent SCS replacement at Albany Medical Center between 2011 and 2020 were identified. The medical records were reviewed for demographic data and information regarding initial complications, reason for removal or revision, subsequent complications of replacement surgery and its timing, and whether the implant was ultimately removed. Percutaneous lead replacement cases performed over the same period were used as a comparison group. ResultsA total of 1265 patients were identified to have had an SCS-related procedure based on billing codes. Of these, 73 involved replacement of epidural leads (51 paddles, 22 percutaneous). Most paddles (48/51) were replaced at the time of removal. A total of 30 of the 51 paddle replacements required additional lamina removal. Re-operations that occurred more than one year after initial implant were significantly more likely to require additional bone removal (p < 0.001). Paddle re-operations lasted in general 1.7 ± 0.2 hours and had 35 ± 5 mL of blood loss, whereas percutaneous operations lasted 1.3 ± 0.2 hours and had 12.5 ± 2 mL of blood loss. Despite the invasive nature of paddle replacement, there was no difference in complications (p = 0.23) compared with that in percutaneous leads. ConclusionsThis study characterizes the safety profile of SCS paddle replacement surgeries. Here, we demonstrate that the replacement of paddle leads at the time of removal, with additional lamina removal if needed because of scar, is associated with low rates of complications. This validates the feasibility and low-risk profile of replacing paddle leads when clinically indicated for experienced surgeons with specialization in SCS.

Images in Practice: Replacement of an 18-Year-Old Spinal Cord Stimulator Paddle Lead with Cylindrical Leads Under Direct Visualization.

Images in Practice: Replacement of an 18-Year-Old Spinal Cord Stimulator Paddle Lead with Cylindrical Leads Under Direct Visualization.

Awake Implantation of Thoracic Spinal Cord Stimulator Paddle Electrode and Generator: 2-Dimensional Operative Video.

In this surgical video, the operative technique is presented for awake implantation of a thoracic paddle electrode for spinal cord stimulation. In the first stage, a laminotomy is performed with the patient under conscious sedation. Once the paddle is in optimal position, the patient is tested intraoperatively to confirm adequate coverage and absence of untoward side effects. This paddle electrode is used for the trial period. If the patient derives satisfactory pain relief during the trial, they are returned for the second stage implantation of pulse generator, without moving the initial paddle electrode now already placed in an optimal location. Particular attention in this video is provided toward the optimal positioning and technique for the awake laminotomy to ensure patient comfort and reliability during testing, the use of extension leads tunneled opposite the planned pulse generator site, and the method of removing extension leads to preserve the placement of the initial paddle electrode.

Commentary: Implantation of a Thoracic Spinal Cord Stimulator Paddle Electrode and Generator Under General Anesthesia With Intraoperative Neuromonitoring: 2-Dimensional Operative Video.

Commentary: Implantation of a Thoracic Spinal Cord Stimulator Paddle Electrode and Generator Under General Anesthesia With Intraoperative Neuromonitoring: 2-Dimensional Operative Video.

Rate of Complications Following Spinal Cord Stimulation Paddle Electrode Removal

Spinal cord stimulation (SCS) is a safe, reversible surgical treatment for complex regional pain syndrome and failed back surgery syndrome refractory to conventional medical management. Paddle electrodes are routinely used for the permanent implant because of the reduced risk of migration, lower energy requirements, and expanded coverage options. The risks associated with paddle lead removal are not well defined in the literature. We retrospectively reviewed the outcomes of all patients at the Cleveland Clinic who underwent removal of SCS paddle electrodes between 2009 and 2016. We identified 68 patients during this interval who had a paddle electrode removed. The most common reason for removal was loss of coverage or effect (75%), followed by infection (13.24%), and the need for magnetic resonance imaging for diagnostic purposes (8.82%). Postoperative complications occurred in eight patients (11.75%), two of which were classified as major (2.94%). One of these patients developed a postoperative cerebrospinal fluid leak, and another suffered a large suprafascial hematoma. Both patients underwent reoperation. Minor complications were reported in six patients (8.82%) and included wound dehiscence, infection, and prolonged ileus in one case. On average, patients who developed complications lost 20 mL more blood during surgery than those who did not develop complications (p = 0.006). One of the benefits of SCS therapy is the reversibility of the procedure. However, removal is not without some risk though the overall risk of minor or major complication is low. Patients who are considering removal should be counseled appropriately. Prophylactic removal is not recommended. However, when removal is needed, surgeons and pain specialists must be familiar with these complications and their management.

Minimally Invasive Placement of Spinal Cord Stimulator Paddle Electrodes Is Associated With Improved Perioperative and Long-Term Experience Among Neuropathic Pain Patients.

Prospective, observational cohort study. This study compared in-hospital and long-term outcomes among spinal cord stimulation (SCS) patients undergoing paddle insertion by open or minimally invasive surgery (MIS) approaches. Patients with treatment-refractory extremity neuropathic pain may benefit from SCS. Conventional placement of surgical paddles for an external neurostimulation trial is through open laminectomy, but MIS techniques may offer advantages. Twenty SCS patients were prospectively assessed. Open patients underwent caudal thoracic laminectomy for multicolumnar electrode paddle placement. MIS patients underwent paddle placement through interlaminar flavectomy using tubular retractors. Demographic data included age, sex, underlying diagnosis, and preoperative visual analog scale (VAS) extremity scores. Intraoperative data included operative duration, blood loss, and number of device passages to achieve final position. Perioperative data included VAS back pain scores; trial data included time-to-trial and time-to-decision. Postoperative data included 1 month VAS back pain scores and 1 year follow-up device complications. No demographic differences were observed among surgical cohorts. MIS procedures had shorter operative duration (P = 0.03), less blood loss (P < 0.001), and similar median number of device passages (2 vs 1.5, P = 0.71). MIS patients reported less perioperative surgical back pain (P < 0.05). External neurostimulation trials began sooner among MIS patients who also made sooner decision whether to implant the SCS device (2.8 ± 1.4 vs 4.3 ± 1.0 days, P = 0.013). Similar 1 month back pain scores were reported between surgical cohorts (P = 0.08). MIS techniques for SCS surgical paddle implantation is associated with less perioperative morbidity and surgical site back pain, shorter external neurostimulator trial duration, and long-term device stability benefits. 2.

Modeling the impact of spinal cord stimulation paddle lead position on impedance, stimulation threshold, and activation region.

The effectiveness of spinal cord stimulation (SCS) for chronic pain treatment depends on selection of appropriate stimulation settings, which can be especially challenging following posture change or SCS lead migration. The objective of this work was to investigate the feasibility of using SCS lead impedance for determining the location of a SCS lead and for detecting lead migration, as well as the impact of axial movement and rotation of the St. Jude Medical PENTA™ paddle in the dorsal-ventral or medial-lateral directions on dorsal column (DC) stimulation thresholds and neural activation regions. We used a two-stage computational model, including a finite element method model of field potentials in the spinal cord during stimulation, coupled to a biophysical cable model of mammalian, myelinated nerve fibers to calculate tissue impedance and nerve fiber activation within the DC. We found that SCS lead impedance was highly sensitive to the distance between the lead and cerebrospinal fluid (CSF) layer. In addition, among all the lead positions studied, medial-lateral movement resulted in the most substantial changes to SC activation regions. These results suggest that impedance can be used for detecting paddle position and lead migration, and therefore for guiding SCS programming.

Intraoperative powdered vancomycin use with paddle lead placement.

This is a prospective case-control study that was conducted to determine if the addition of intraoperative powdered vancomycin placed directly into the wounds at the time of closure might decrease the rate of acute postoperative infection after the placement of spinal cord stimulator paddle leads. A retrospective analysis of the author's practice from January 1, 2009 through July 31, 2012 (Table 1) showed that those patients requiring a laminectomy instead of a laminotomy to insert a paddle lead had an increased rate of acute postop infection. All patients receiving a thoracic spinal cord stimulator paddle from January 1, 2013 through December 31, 2013 were then followed prospectively. Those patients whose paddle leads could be inserted with a laminotomy were treated in a standard fashion. Those patients who required a laminectomy for insertion of the paddle lead received powdered vancomycin placed directly into the wounds prior to closure. One hundred and nine patients underwent implantation of a permanent spinal cord stimulator paddle lead and battery between January 1 and December 31, 2013. Thirty-two of those patients required a laminectomy for implantation of the paddle and received intraoperative powdered vancomycin placed directly into both wounds at the time of closure. The remaining 77 patients were treated in a standard fashion. There were no infections in the laminectomy group and two infections in the laminotomy group. This study indicates that intraoperative powdered vancomycin placed directly into the wounds at the time of closure can produce similar infection rates between the groups of patients requiring a laminectomy vs. a laminotomy for implantation of a thoracic paddle lead. These findings need confirmation by a randomized controlled design study.

Computational modeling analysis of a spinal cord stimulation paddle lead reveals broad, gapless dermatomal coverage.

Spinal cord stimulation (SCS) is an effective therapy for treating chronic pain. The St. Jude Medical PENTA(TM) paddle lead features a 4 × 5 contact array for achieving broad, selective coverage of dorsal column (DC) fibers. The objective of this work was to evaluate DC activation regions that correspond to dermatomal coverage with use of the PENTA lead in conjunction with a lateral sweep programming algorithm. We used a two-stage computational model, including a finite element method model of field potentials in the spinal cord during stimulation, coupled to a biophysical cable model of mammalian, myelinated nerve fibers to determine fiber activation within the DC. We found that across contact configurations used clinically in the sweep algorithm, the activation region shifted smoothly between left and right DC, and could achieve gapless medio-lateral coverage in dermatomal fiber tract zones. Increasing stimulation amplitude between the DC threshold and discomfort threshold led to a greater area of activation and number of dermatomal zones covered on the left and/or right DC, including L1-2 zones corresponding to dermatomes of the lower back. This work demonstrates that the flexibility in contact selection offered by the PENTA lead may enable patient-specific tailoring of SCS.

Prolonged Severe Abdominal Pain Following Spinal Cord Stimulator Implantation: A Case Report of Post-Operative Spinal Cord Stimulator Thoracic Radiculopathy

The use of neuromodulation, specifically spinal cord stimulator, has gained popularity in the management of chronic pain syndromes. Some indications for spinal cord stimulator placement include chronic pain arising from complex regional pain syndrome (CRPS), neuropathy, and post-laminectomy syndrome. With placement of spinal cord stimulator, there have been poorly described cases of post-operative thoracic radiculopathy as a potential complication. This case report describes a patient with prolonged severe thoracic radiculopathy after undergoing spinal cord stimulator paddle lead placement. The patient is a 52 years old female with a history of worsening low back and leg pain not relieved by conservative measures and back surgeries. She underwent successful percutaneous SCS trial with greater than 80% relief of her symptoms; with subsequent implantation of SCS, paddle lead. In the immediate post-operative period, the patient reported good relief of leg pain with spinal cord stimulator turned on. However, she complained of severe, achy bandlike thoracic and abdominal pain. Of note, there were no intraoperative events. Her pain was minimally relieved with medication management. All laboratory work, abdominal and chest radiographs as well endoscopy was negative. With good relief of leg pain with SCS, she declined removal of the paddle lead. There are a few case studies that have described thoracic radiculopathy after spinal cord stimulator placement. In those cases, pain gradually improved within a short duration; and or after removal of the device. This particular patient had prolonged steady 9-10/10 abdominal pain that was not amenable to conservative treatment. Although a rare phenomenon, it is important to know that persistent abdominal pain can be a result of thoracic neurological injury during SCS lead placement.

Tethering Technique for Revision of a Thoracic Spinal Cord Stimulator Paddle: A Case Report

Revision of a displaced permanent spinal cord stimulator paddle lead presents certain challenges, not least of which is how to maintain the implant in the correct position. The author recently encountered a patient whose thoracic lead, which was originally placed in the midline, migrated into the lateral gutter. As a fibrous sheath had already formed around the lead in the displaced position, simply moving it back to the midline was felt to have a low probability of success. The author was able to successfully reposition the implant and anchor it with a technique that was recently presented for use in the cervical spine ( 1. Amrani J. A novel technique for the implantation of paddle leads in the cervical spine. Neuromodulation 2013. DOI: 10.1111/ner.12022 Google Scholar ).