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

BACKGROUND: 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. OBJECTIVE: This imaging study was undertaken to determine the minimum canal diameter required for safe paddle lead placement. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Upper airway stimulation device failure: A 7-year single center experience.

OBJECTIVE: To identify and report a single center experience with upper airway stimulator device-related failures. STUDY DESIGN: Retrospective case series. SETTING: Single tertiary academic center. METHODS: Retrospective data on 352 patients who underwent UAS surgery with an Inspire device from 2016 to 2023 was collected, including demographics, comorbidities, and nature of device failure requiring revision surgery. RESULTS: Out of the 348 patients included in our analysis, 16 (4.6 %) required revision due to device failure, with an average interval of 772 days (∼2 years) between initial implant and revision. Most failures were attributed to respiratory sensing lead damage (n = 11, 68.8 %), resulting in high system impedance and subsequent device malfunction. Lead fracture causes varied, including idiopathic occurrences and potential trauma. Lead migration was noted in one case (6.3 %), where the hypoglossal electrode detached from the nerve. Two patients (12.3 %) required implantable pulse generator (IPG) replacement, one after experiencing trauma and the other due to unclear source of malfunction. One patient (6.3 %) required complete system replacement following high lead impedance and absent tongue motion. The last patient required replacement of both the IPG and respiratory lead after experiencing high lead impedance (6.3 %). CONCLUSION: Respiratory sensing lead fracture emerged as the leading cause of device failure in this cohort, underscoring the need to address this under-reported issue, potentially linked to the time lapse after device implantation.

Implanted Peroneal Nerve Stimulator Treatment for Drop Foot Caused by Central Nervous System Lesion: A Twelve-Month Follow-up of 21 Patients.

OBJECTIVE: Drop foot is a common impairment following stroke or other causes of central pathology. We report data on patient self-perceived performance, satisfaction with performance, walking ability, and adverse effects after surgical implantation of the ActiGait® drop foot stimulator. DESIGN: Prospective case study with a 12-month follow-up. SUBJECTS: Twenty-one participants with drop foot caused by central nervous system lesion. METHODS: The patients' self-perceived performance and satisfaction with performance were evaluated using the Canadian Occupational Performance Measure (COPM). Walking ability was assessed using a 10-m walk test and a 6-min walk. Nerve conduction of the peroneal nerve was examined in 10 patients. RESULTS: At follow-up, COPM self-percieved performance from 3.2 to 6.7 points, the median increase being 2.8 (interquartile range (IQR) 2.2-5.0), p < 0.001. Likewise, the COPM satisfaction with performance increased from 2.6 to 6.9 points, the median increase being 4.2 (IQR 2.8-5.8), p < 0.001. Walking velocity increased 0.1 m/s from a baseline measurement of 0.73 m/s (95% confidence interval (95% CI) 0.03-0.2), n = 21, p < 0.01, and walking distance increased by 33 m, from a baseline measurement of 236 m (95% CI 15-51), n = 21, p < 0.001. CONCLUSION: Stimulation of the peroneal nerve by an implantable stimulator increases self-perceived performance, satisfaction with performance, and ambulation in patients with long-lasting drop foot caused by a central nervous system lesion.

Adverse Events in Hypoglossal Nerve Stimulator Implantation: 5-Year Analysis of the FDA MAUDE Database.

OBJECTIVE: Use of hypoglossal nerve stimulator implantation has dramatically improved the surgical treatment of multilevel airway collapse during obstructive sleep apnea (OSA). Understanding causes of adverse events and their impact on patients undergoing stimulator implantation will help improve patient preparation and surgical practices to avoid future complications. STUDY DESIGN: This study is a retrospective review of the US Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE) database, a publicly available voluntary reporting system. SETTING: National patient event database. METHODS: The MAUDE database was searched for reports associated with the terms "hypoglossal nerve stimulator" and "Inspire," being the only currently FDA-approved system for upper airway stimulation for OSA. All records were searched with the events limited in dates between May 2014 and September 2019. RESULTS: A total of 132 patient reports were identified over the 5-year inclusion period, containing 134 adverse events. The reported adverse events resulted in 32 device revision procedures as well as 17 explantations. Device migration and infection were 2 of the most commonly reported adverse events. Complications not witnessed in previous large-scale clinical trials included pneumothorax, pleural effusion, and lead migration into the pleural space. CONCLUSION: Previous data have demonstrated hypoglossal nerve stimulator implantation results in reliable OSA improvement. However, a number of technical difficulties and complications still exist during the perioperative period, which should be communicated to patients during the surgical consent process.

Multiple magnetic resonance imaging in patients with implanted sacral nerve stimulator.

AIM: The aim of this study was to assess possible impacts of multiple magnetic resonance imaging (MRI) scans on the function of InterStim™ sacral neurostimulator systems (SNS; Medtronic Inc.) devices and on patient's safety. METHODS: Over the course of 17 years, a total of 16 patients required 72 MRI examinations in various parts of the body. Each time an MRI was performed, the implanting urologist evaluated the SNS device function and deactivated the implant before the scan. Patients were monitored continuously during and after the procedure. After the MRI session, the site of the implanted device was examined, and the SNS device was reactivated. RESULTS: None of the patients experienced pain or discomfort during or after the MRI scan. Impedances and stimulation amplitudes were recorded before and after MRI and showed no statistically significant changes regarding implant function. Micturition-time charts after MRI procedures were compared with previous records and showed no deviations either. No negative consequences of multiple MRIs have been observed. CONCLUSION: This is the first report of patients successfully undergoing multiple MRI scans despite a previously implanted SNS. Sixteen patients underwent more than one MRI scan, with no negative effect on the functional outcome of SNS or negative side effects for the patients.

Sacral Nerve Stimulation in Parkinson's Disease Patients With Overactive Bladder Symptoms.

OBJECTIVE: To assess the efficacy, safety, and outcomes of sacral nerve stimulation (SNS) for Parkinson's disease (PD) patients with overactive bladder symptoms. METHODS: We retrospectively reviewed PD patients who underwent Stage I SNS. Demographics, urodynamic data, and baseline voiding function were analyzed. Efficacy and safety of treatment were determined by rate of progression to Stage II, explantation, and surgical revision. Long-term outcomes were assessed using voiding diaries and/or clinic notes. RESULTS: Sixty percent (9/15) experienced ≥50% improvement in urinary parameters and proceeded to Stage II. There was no significant difference in age, body mass index, comorbidities, PD disease duration, or levodopa equivalent daily dose between successful and nonsuccessful Stage I patients. However, 100% of female patients experienced Stage I success compared to 44% of male PD patients (P = .04). Individuals with >12-month follow-up experienced an average reduction of 6 voids/day. No patients required revision or explantation of their device at latest clinic follow-up (22.2 ± 7.8 months). Higher maximal urethral closure pressures, detrusor pressure at maximum flow rate (PdetQmax), post-void residual volume, and mean bladder outlet obstruction index were observed in the Stage I trial failures. CONCLUSION: At our institution, PD patients have a similar rate of progression to Stage II compared to the general population. SNS is an effective therapy that should be considered among the treatment options for PD patients with overactive bladder symptoms. Urodynamic parameters associated with obstruction may be predictive of SNS failure in PD patients and may help guide patient selection, however further studies are needed.

Chronic nerve health following implantation of femoral nerve cuff electrodes.

BACKGROUND: Peripheral nerve stimulation with implanted nerve cuff electrodes can restore standing, stepping and other functions to individuals with spinal cord injury (SCI). We performed the first study to evaluate the clinical electrodiagnostic changes due to electrode implantation acutely, chronic presence on the nerve peri- and post-operatively, and long-term delivery of electrical stimulation. METHODS: A man with bilateral lower extremity paralysis secondary to cervical SCI sustained 5 years prior to enrollment received an implanted standing neuroprosthesis including composite flat interface nerve electrodes (C-FINEs) electrodes implanted around the proximal femoral nerves near the inguinal ligaments. Electromyography quantified neurophysiology preoperatively, intraoperatively, and through 1 year postoperatively. Stimulation charge thresholds, evoked knee extension moments, and weight distribution during standing quantified neuroprosthesis function over the same interval. RESULTS: Femoral compound motor unit action potentials increased 31% in amplitude and 34% in area while evoked knee extension moments increased significantly (p < 0.01) by 79% over 1 year of rehabilitation with standing and quadriceps exercises. Charge thresholds were low and stable, averaging 19.7 nC ± 6.2 (SEM). Changes in saphenous nerve action potentials and needle electromyography suggested minor nerve irritation perioperatively. CONCLUSIONS: This is the first human trial reporting acute and chronic neurophysiologic changes due to application of and stimulation through nerve cuff electrodes. Electrodiagnostics indicated preserved nerve health with strengthened responses following stimulated exercise. Temporary electrodiagnostic changes suggest minor nerve irritation only intra- and peri-operatively, not continuing chronically nor impacting function. These outcomes follow implantation of a neuroprosthesis enabling standing and demonstrate the ability to safely implant electrodes on the proximal femoral nerve close to the inguinal ligament. We demonstrate the electrodiagnostic findings that can be expected from implanting nerve cuff electrodes and their time-course for resolution, potentially applicable to prostheses modulating other peripheral nerves and functions. TRIAL REGISTRATION: ClinicalTrials.gov NCT01923662 , retrospectively registered August 15, 2013.

One-year outcomes of the ARTISAN-SNM study with the Axonics System for the treatment of urinary urgency incontinence.

AIMS: Sacral neuromodulation (SNM) is a guideline-recommended treatment for voiding dysfunction including urgency, urge incontinence, and nonobstructive retention as well as fecal incontinence. The Axonics® System is a miniaturized, rechargeable SNM system designed to provide therapy for at least 15 years, which is expected to significantly reduce revision surgeries as it will not require replacement as frequently as the non-rechargeable SNM system. The ARTISAN-SNM study is a pivotal study designed to treat patients with urinary urgency incontinence (UUI). Clinical results at 1-year are presented. METHODS: A total of 129 eligible UUI patients were treated. All participants were implanted with a quadripolar tined lead and neurostimulator in a single procedure. Efficacy data were collected using a 3-day bladder diary, a validated quality of life questionnaire (ICIQ-OABqol), and a participant satisfaction questionnaire. Therapy responders were defined as participants with ≥50% reduction in UUI episodes compared to baseline. Data were analyzed on all 129 participants. RESULTS: At 1 year, 89% of the participants were therapy responders. The average UUI episodes per day reduced from 5.6 ± 0.3 at baseline to 1.4 ± 0.2. Participants experienced an overall clinically meaningful improvement of 34 points on the ICIQ-OABqol questionnaire. All study participants (100%) were able to recharge their device at 1 year, and 96% of participants reported that the frequency and duration of recharging was acceptable. There were no serious device-related adverse events. CONCLUSIONS: The Axonics System is safe and effective at 1 year, with 89% of participants experiencing clinically and statistically significant improvements in UUI symptoms.

Peripheral trigeminal branch stimulation for refractory facial pain: A single-center experience.

OBJECTIVE: Facial pain refractory to medical treatments may benefit from neurosurgical interventions. Only a few studies have reported on the efficacy of peripheral trigeminal stimulation and more specifically supraorbital nerve (SON) and infraorbital nerve (ION) stimulation for the treatment of facial pain. PATIENTS AND METHODS: In the present study, we identified all patients at our institution who underwent SON and/or ION stimulation for treatment of facial pain due to post-herpetic, traumatic or idiopathic etiology. Relevant pre and post-operative outcomes were analyzed. RESULTS: We identified 15 patients who underwent SON and/or ION stimulation. Among them, 12 (80 %) endorsed >50 % pain relief during the trial stimulation period. After a median follow-up of 5.8 months with permanent implantation, 1 patient (8.3 %) was diagnosed with lead erosion and IPG migration, two patients had lead infections (16.7 %) and one (8.3 %) had wound dehiscence. No lead migrations were identified during the long-term follow-up. The VAS score showed a statistically significant reduction from a median pre-operative score of 7 to a post-operative score of 1.8 (p = 0.011), which corresponded to a 74.3 % average pain reduction. CONCLUSION: SON and/or ION stimulation can be an effective treatment for intractable facial pain due to post-herpetic, traumatic or idiopathic etiology; however the complication rate is relatively high. Future prospective studies with longer follow-up periods are warranted.

Peripheral nerve field stimulation in medically refractory trigeminal neuralgia attributed to multiple sclerosis.

OBJECTIVE: Case reports and small patient series have suggested peripheral nerve field stimulation (PNFS) as a treatment for refractory trigeminal neuralgia attributed to multiple sclerosis (MS). Here, the authors aimed to assess the effects of this technique on long-term pain severity. METHODS: Data were prospectively collected on patients with refractory trigeminal neuralgia attributed to MS who underwent PNFS between July 2013 and August 2017 at the authors' neurosurgical department. Patients were evaluated before and after the first treatment as well as at follow-up at least twice a year. Patients underwent assessment of their pain severity using the Barrow Neurological Institute (BNI) Scale before treatment and at follow-up and were questioned about adverse events following cranial MRI performed after implantation of a permanent PNFS system. RESULTS: Eight patients (3 women) underwent PNFS trials and their median age was 61 years (IQR 73.75 - 46.5 years). Seven patients proceeded to permanent implantation of the stimulation system. At a median follow-up of 33 months (IQR 42 - 24 months), pain severity decreased from baseline to the last follow-up (BNI score decrease from V [IQR V - V] to III [IQR V - III], p = 0.054). Four patients experienced long-lasting benefit (at 48, 33, 24, and 15 months' follow-up, respectively), while in 3 patients the treatment eventually failed after an initially successful period. One patient had an infection, requiring system removal and subsequent reimplantation. No other complications occurred. No adverse events were noted in the patients undergoing MRI postimplantation. CONCLUSIONS: This analysis indicates a possibly beneficial long-term effect of PNFS on refractory trigeminal neuralgia attributed to MS in some patients.

Patterns of tined lead migration in sacral nerve modulation.

AIM: Lead migration is a common cause of loss of efficacy in sacral nerve modulation. Our aim was to systematically study the migration pattern of tined leads in sacral nerve modulation. Our hypothesis was that tined leads may promote forward migration because of their configuration. METHOD: Consecutive patients treated with sacral nerve modulation with a tined lead electrode, who had experienced loss of efficacy and had radiographs both at baseline and after loss of efficacy between 2005 and 2016 were eligible for inclusion. RESULTS: Twenty-five patients out of 70 with loss of efficacy were studied. Lead migration was measured as percent electrode movement in relation to sacral cortex at lateral projection. All had some degree of lead migration, ranging from 35% backward to 74% forward migration. Sixteen (64%) had forward migration while nine (36%) had backward migration. In seven patients (28%), loss of efficacy was associated with an episode of perceived mechanical strain on the electrode. Fifty percent (4/8) who associated their loss of efficacy with an adverse event had forward migration of the electrode. CONCLUSIONS: Forward lead migration with concomitant loss of efficacy seems to be a common event in patients with tined leads, hence supporting our hypothesis. The retrospective design and that some of the patients with loss of efficacy could not be included because of incomplete data, which is a limitation to the study. Further studies are needed to confirm to what extent the direction and magnitude of the migration relate to loss of efficacy.

Sacral Neuromodulation Lead Twisting Causes Migration and Loss of Efficacy.

OBJECTIVE: This study aimed to present 2 cases with unusual lead complications in InterStim devices implanted in patients with refractory overactive bladder symptoms. MATERIALS: Two patients with InterStim implants presented with loss of efficacy. Both patients required lead revision surgery with findings of a twisted lead with associated lead migration. RESULTS: In both cases, revision surgery revealed twisting of the InterStim lead causing retrograde lead displacement. Patients were managed with lead removal and placement of a new lead. At the time of revision, one patient had a seroma within a large pocket of the implantable pulse generator (IPG) site, which was managed with closure and development of a new IPG pocket. In both cases, revision with new lead placement resulted in significant symptom improvement. CONCLUSIONS: Sacral neuromodulation lead complications are known to be among the most consequential adverse events. We report the first 2 cases, to our knowledge, of patients presenting with an InterStim device that lost efficacy due to lead twisting and subsequent retrograde lead migration, likely due to rotation of the IPG within the gluteal pocket. This finding is easily remedied with IPG pocket revision and lead replacement.

DBS dysfunction mimicking transient ischemic attacks-a case report.

We report on a patient with thalamic deep brain stimulation (DBS) for essential tremor who was admitted to a stroke unit with transient vertigo, dysarthria, and gait disturbance. Transient ischemic attacks were assumed but fluctuating neurological symptoms persisted until presentation to a DBS center. Here, unstable high monopolar impedances of the right-hemispheric electrode contacts were detected. Surgical revision revealed a fracture of the pocket adaptor connecting this electrode to the impulse generator. Replacement resulted in stable impedances and remitted the transient neurological symptoms. Emergency and stroke doctors should be aware of neurological symptoms induced by technical dysfunctions in DBS.

Electrical safety.

Since the purpose of clinical neurophysiology testing is to record the electrical activity of the nervous system, and often to electrically stimulate the peripheral or central nervous system (for evoked potentials, nerve conduction studies, etc.), these tests by their very nature demand an excellent electrical connection to the patient. This direct electrical connection by definition puts the patient at increased risk of electrical shock. When patients suffer from other nonneurological disorders that also require equipment to be attached to or inserted into their body, the additional and more direct electrical pathways to the heart make them even more vulnerable, especially when undergoing monitoring in the operating room or intensive care unit. Although we depend on the hospital's construction and utilities to follow appropriate regulations (the National Electrical Code in the United States) and on the vendors to sell only safe equipment (approved by the Food and Drug Administration in the United States), there may exist combinations of equipment and connections that put the patient at risk of injurious or fatal electrical shock. Regular testing and safe practices, informed by a scientific understanding of the risks, are the responsibilities of the healthcare providers in order to protect the patient from harm from electricity.

Occipital nerve stimulation for non-migrainous chronic headaches: a systematic review protocol.

BACKGROUND: Defined as a headache lasting at least 15 days per month, chronic headache is reported by 3% of the general population, and a substantial proportion of them are refractory to current therapies. Occipital nerve stimulation (ONS) is a treatment option, but is still considered as a last resort treatment especially because of its invasive nature and the cost associated. Some reviews reported a limited efficacy of ONS for the treatment of migraines, with a high risk of complications. However, results reporting its efficacy and safety on other headache disorders are unclear. The aim of this review is to assess the efficacy and safety of ONS in regards to non-migrainous chronic headaches. METHODS: We will conduct a systematic review and meta-analysis of studies evaluating the use of ONS in comparison to sham stimulation or the best available treatment in patients with chronic headache. MEDLINE, CINHAL, EMBASE, PsycINFO, ECRI Institute Library, WIKISTIM, the Cochrane Library databases, and clinical trial registries will be searched for eligible studies. The review will include adult patients diagnosed with chronic headache excluding migraine. Two independent reviewers will process to the screening of studies according to titles, abstracts, and then full texts. The primary outcome is the overall reduction of head pain severity. The secondary outcomes are rates of reduction in the severity of head pain, headache frequency, and duration, use of medication, impairment, quality of life, healthcare utilization, return to work, and adverse events. Extracted data will include patients' and procedure characteristics, details on comparative treatment or sham, and clinical outcomes. The risk of bias of the studies will be also independently assessed using the Cochrane risk of bias tools. DISCUSSION: This systematic review will allow us to better evaluate the potential role of ONS for the treatment of patients with chronic headache that are refractory to less invasive therapies. It will help to determine the degree of safety of ONS. Moreover, it will help to design and conduct future randomized controlled trials focused on patients who may better respond to such treatment. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019121623.

Implantable Electronic Stimulation Devices from Head to Sacrum: Imaging Features and Functions.

Electronic stimulation devices are implanted in various locations in the body to decrease pain, modulate nerve function, or stimulate various end organs. The authors describe these devices using a craniocaudal approach, first describing deep brain stimulation (DBS) devices and ending with sacral nerve stimulation (SNS) devices. The radiology-relevant background information for each device and its imaging appearance are also described. These devices have a common design theme and include the following components: (a) a pulse generator that houses the battery and control electronics, (b) an insulated lead or wire that conveys signals to the last component, which is (c) an electrode that contacts the end organ and senses and/or acts on the end organ. DBS electrodes are inserted into various deep gray nuclei, most commonly to treat the symptoms of movement disorders. Occipital, trigeminal, and spinal nerve stimulation devices are used as second-line therapy to control craniofacial or back pain. For cardiac devices, the authors describe two newer devices, the subcutaneous implantable cardioverter defibrillator and the leadless pacemaker, both of which avoid complications related to having leads threaded through the venous system. Diaphragmatic stimulation devices stimulate the phrenic nerve to restore diaphragmatic movement. Gastric electrical stimulation devices act on various parts of the stomach for the treatment of gastroparesis or obesity. Finally, SNS devices are used to modulate urinary and defecatory functions. Common complications diagnosed at imaging include infection, hematoma, lead migration, and lead breakage. Understanding the components, normal function, and normal imaging appearance of each device allows the radiologist to identify complications. ©RSNA, 2019.

Neurologic Injury After Sacral Neuromodulation.

OBJECTIVE: Neurologic injury after sacral nerve stimulation (SNS) is rare, but the incidence is unknown. Infection is a potential mechanism for neurologic damage. This report illustrates the presentation, pathophysiology, diagnostic considerations, and treatment of epidural infection causing neurologic deficits after SNS. CASE REPORT: We present a case of a woman with severe fecal incontinence due to Crohn's disease who underwent SNS implantation and subsequently developed a wound infection requiring complete device explantation. A few days later, she presented with leg pain and weakness. Urgent evaluation and treatment of epidural infection were performed. She had persistent neurologic deficits 6 months later. CONCLUSIONS: Neurologic sequelae from an infection after SNS are a rare event and should be considered in patients with fevers, leg pain, and neurologic deficits.

Pseudomeningocele and percutaneous intrathecal lead placement complication for spinal cord stimulator.

The incidence of symptomatic percutaneous intrathecal subarachnoid lead placement for spinal cord stimulator is almost an unheard of complication in the literature. We present the first case of a spinal cord stimulator implant with a complication of symptomatic intrathecal subarachnoid lead placement with a pseudomeningocele. This complication was found with myelogram and addressed by replacement with a new spinal cord stimulator implant with paddle leads instead of percutaneous leads and obliterating the pseudomeningocele tract. Technique for epidural lead placement is discussed. This case illustrates a spinal cord stimulator implant complication of intrathecal percutaneous lead placement with pseudomeningocele and its recognition and treatment involving replacement of the system while minimizing risk of postoperative cerebrospinal fluid leakage. Intraoperative neuromonitoring and interrogation of the spinal cord stimulator system during implantation are effective tools for accurate epidural lead placement.

Dexamethasone Reduces the Foreign Body Reaction to Intraneural Electrode Implants in the Peripheral Nerve of the Rat.

Intraneural electrodes must be in intimate contact with nerve fibers to have a proper function, but this interface is compromised due to the foreign body reaction (FBR). The FBR is characterized by a first inflammatory phase followed by a second anti-inflammatory and fibrotic phase, which results in the formation of a tissue capsule around the implant, causing physical separation between the active sites of the electrode and the nerve fibers. We have tested systemically several anti-inflammatory drugs such as dexamethasone (subcutaneous), ibuprofen and maraviroc (oral) to reduce macrophage activation, as well as clodronate liposomes (intraperitoneal) to reduce monocyte/macrophage infiltration, and sildenafil (oral) as an antifibrotic drug to reduce collagen deposition in an FBR model with longitudinal Parylene C intraneural implants in the rat sciatic nerve. Treatment with dexamethasone, ibuprofen, or clodronate significantly reduced the inflammatory reaction in the nerve in comparison to the saline group after 2 weeks of the implant, whereas sildenafil and maraviroc had no effect on infiltration of macrophages in the nerve. However, only dexamethasone was able to significantly reduce the matrix deposition around the implant. Similar positive results were obtained with dexamethasone in the case of polyimide-based intraneural implants, another polymer substrate for the electrode. These results indicate that inflammation triggers the FBR in peripheral nerves, and that anti-inflammatory treatment with dexamethasone may have beneficial effects on lengthening intraneural interface functionality. Anat Rec, 301:1722-1733, 2018. © 2018 Wiley Periodicals, Inc.