Fourth ventricular subarachnoid stent for Chiari malformation type I-associated persistent syringomyelia.

OBJECTIVE: Syringomyelia (syrinx) associated with Chiari malformation type I (CM-I) is commonly managed with posterior fossa decompression, which can lead to resolution in most cases. A persistent syrinx postdecompression is therefore uncommon and challenging to address. In the setting of radiographically adequate decompression with persistent syrinx, the authors prefer placing fourth ventricular subarachnoid stents that span the craniocervical junction particularly when intraoperative observation reveals arachnoid plane scarring. The objective of this study was to evaluate the safety and efficacy of a fourth ventricle stent for CM-I-associated persistent syringomyelia, assess dynamic changes in syrinx dimensions, and report stent-reduction durability, clinical outcomes, and procedure-associated complications. METHODS: The authors performed a single-institution, retrospective review of patients who underwent fourth ventricular subarachnoid stent placement for persistent CM-I-associated syringomyelia following a prior posterior fossa decompression. The authors' institutional Chiari database contains 600 cases with 149 decompressions for CM-I-associated syringomyelia, of which 13 met criteria for inclusion. Data on patient demographics, clinical presentation and outcomes, and MRI findings were collected. The maximal syrinx diameter was estimated by calculating the area of an elliptical cross-section in the largest axial plane from preoperative, immediately postoperative, and late postoperative T2-weighted MR images. RESULTS: All 13 patients experienced a significant decrease in mean syrinx area from the preoperative to the late postoperative MRI (mean syrinx diameter 114.1 ± 81.8 mm2 vs 24.5 ± 23.8 mm2, p < 0.001). The mean time until late postoperative MRI was 19.7 months (range 2.0-70.7 months). The syrinx area reduced on average by 75.0% ± 23.9% at the time of the last postoperative scan. Syrinx resolution was variable, with 4 patients (30.8%) achieving near-complete resolution (> 90%, grade III reduction), 7 patients (50%) having 50%-90% reduction (grade II), and 2 patients (14.3%) having < 50% decrease (grade I). One patient experienced catheter migration into the left brachium pontis with an associated cyst at the tip of the catheter that decreased in size on follow-up imaging. CONCLUSIONS: Placement of fourth ventricular subarachnoid stents spanning the craniocervical junction in patients with persistent CM-I-associated syringomyelia after posterior fossa decompression is a safe therapeutic option and significantly reduced the mean syrinx area, with a greater reductive effect seen over longer follow-up periods.

A smartphone pupillometry tool for detection of acute large vessel occlusion.

OBJECTIVES: Pupillary light reflex (PLR) parameters can be used as quantitative biomarkers of neurological function. Since digital infrared pupillometry is expensive, we sought to examine alterations in PLR parameters using a smartphone quantitative pupillometry platform in subjects with acute ischemic stroke (AIS). MATERIALS AND METHODS: Patients were enrolled if they presented to the emergency department as a stroke code activation and had evidence of a large vessel occlusion (LVO) on computed tomography angiography. Controls were enrolled from hospital staff. A smartphone pupillometer was used in AIS patients with LVO pre-mechanical thrombectomy, immediately post-thrombectomy, and at 24 h post-thrombectomy. Clinical and demographic data were collected, along with the proprietary Neurological Pupil index (NPi) score from the NPi-200 digital infrared pupillometer. PLR parameters were compared using mean differences. The absolute and non-absolute inter-eye difference in each parameter for each subject were also analyzed by measuring 1 - (R:L) to determine alteration in the equilibrium between subject pupils. The NPi was analyzed for mean differences between cohorts. RESULTS: Healthy controls (n = 132) and AIS patients (n = 31) were enrolled. Significant differences were observed in PLR parameters for healthy subjects when compared to pre-thrombectomy subjects in both mean and absolute inter-eye differences after post hoc Bonferroni correction. The proprietary NPi score was not significantly different for all groups and comparisons. CONCLUSIONS: Significant alterations in the PLR were observed in AIS patients with LVO before thrombectomy, indicating the potential use of smartphone pupillometry for detection of LVO.

Myofascial Flap Closure Decreases Complications in Complex Surgery of the Craniocervical Junction in Ehlers-Danlos Patients.

INTRODUCTION: Patients with Ehlers-Danlos syndrome (EDS) are at elevated risk for soft tissue complications when undergoing decompression with or without fusion of the craniocervical junction. We have previously shown that muscle flap closure can decrease reoperative rates. This study investigated whether myofascial flap closure improved clinical outcomes after simple or complex surgery of the craniocervical junction in EDS patients specifically. METHODS: We performed a retrospective chart review of EDS patients who had undergone surgery for Chiari malformation at the Weill Cornell Medical Center between 2013 and 2020. Postoperative complications were recorded, including infection, wound dehiscence, seroma, hematoma, hardware removal, cerebrospinal fluid (CSF) leak, reoperation, and pseudomeningocele. Patients were stratified by type of closure and type of surgery. Fisher exact test was used for statistical comparison. RESULTS: Between 2013 and 2020, 62 EDS patients who had surgery of the cervicocranial junction were reviewed. Of these, 31 patients had complex surgery with myofascial flap closure and 22 had simple surgery with traditional closure. The mean age at the time of surgery was 21.3 years. There were no significant differences in wound complications or reoperation rates between the simple surgery and complex surgery groups. In addition, there were no significant differences in complications between complex surgery with flap closure and simple surgery with traditional closure. Our CSF cutaneous fistula rate was 0%, considerably lower than rates reported in the literature, and, in one case, a patient developed a postoperative pseudomeningocele secondary to a dural leak, but the myofascial flap closure prevented its progression. CONCLUSIONS: Patients with EDS undergoing surgery of the cervicocranial junction may benefit from myofascial flap closure. Flap closure reduced complications after complex surgery of the craniocervical junction to the level of simple surgery. Our CSF leak rate was exceptionally low and only one patient experienced pseudomeningocele. Myofascial flaps are safe to perform in the EDS cohort and prevented CSF cutaneous fistula formation.

Revision Chiari Surgery in Young Children: Predictors and Outcomes.

INTRODUCTION: Children aged 0-6 years with Chiari malformation (CM) often present with atypical symptoms and require revision surgery more often than older children. We studied characteristics and outcomes of CM patients in this age-group who underwent one or more revision surgeries to assess how often revision surgery is necessary and successful in this age-group. METHODS: We retrospectively reviewed patients who were diagnosed with CM 1 or CM 1.5 and surgically treated with posterior fossa decompression (PFD) with or without duraplasty before their 7th birthday. Basic demographics, preoperative presentation, operative details, and postoperative outcomes were analyzed. RESULTS: Forty patients (mean age 3.2 ± 1.7 years, 35% female) were reviewed. The most common presenting symptoms were headache, dysphagia, and respiratory problems. Eight patients required one or more revision surgeries 11.6 ± 7.6 months on average after their initial surgery. Comparing the revision and no revision groups, dysautonomia was significantly more common prior to initial surgery in the children requiring revision (37.5 vs. 3.1%, p = 0.02). The revision group also trended toward more dysphagia (75.0 vs. 46.9%, p = 0.24) and respiratory problems (75.0 vs. 40.6%, p = 0.12). The most frequent reasons for reoperation were symptom recurrence (6/8), residual posterior fossa compression (3/8), significant scar tissue formation (2/8), ventral brainstem compression (1/8), and suspected craniocervical instability (1/8). Of the 8 children undergoing reoperation, surgery achieved symptom resolution or improvement in 5, while 3 had unchanged symptoms. Two patients underwent a third surgery, after which 1 showed improvement and the other did not. This last patient showed short-term improvement after a fourth surgery but had symptom recurrence 12 months later. DISCUSSION/CONCLUSION: Oropharyngeal and respiratory problems are particularly common in children aged 0-6 years with CM. Presentation with dysautonomia or other signs of brainstem compression will often predict an additional surgery will be needed after an initial PFD. Symptom recurrence is the most frequent reason for reoperation, and revision surgeries lead to improved clinical outcomes in the majority but not all of these young patients. Surgery in very young children is successful, but reoperation should be integrated into an up-front discussion algorithm particularly in children with severe symptoms.

A lifeline in the dark: Breaking through the stigma of veteran mental health and treating America's combat veterans.

For generations, veterans have answered the call to service and served their country honorably and with distinction. Unfortunately, the consequences of combat cause many veterans to struggle with life after the military and with readjustment/reintegration into civilian life. Today more than ever, there are a multitude of resources, education, and treatment options for combat veterans. For mental and physical health providers, business leaders, and other professionals who work with veterans, it is of the upmost importance that they learn about programs around them that are successful in treating veterans. The current article reviews two U.S. Department of Veterans Affairs nationwide programs-the Readjustment Counseling Service/Vet Center and Veteran Cultural Competence Training-designed to decrease mental health stigma for veterans and to increase veteran engagement with mental health services. These programs highlight the importance of being aware of the culture within military systems, being aware of personal biases, and fostering an environment of genuineness, safety, and nonjudgmental empathy. In doing so, these programs are successful in reducing the unspoken power of stigmatization; they effectively reach out to veterans in need, providing a lifeline in the dark.

Medical Rehabilitation: Guidelines to Advance the Field With High-Impact Clinical Trials.

The purpose of this Special Communication is to summarize guidelines and recommendations stemming from an expert panel convened by the National Institutes of Health, National Center for Medical Rehabilitation Research (NCMRR) for a workshop entitled The Future of Medical Rehabilitation Clinical Trials, held September 29-30, 2016, at the NCMRR offices in Bethesda, Maryland. The ultimate goal of both the workshop and this summary is to offer guidance on clinical trials design and operations to the medical rehabilitation research community, with the intent of maximizing the effect of future trials.

In Vitro Magnetic Resonance Imaging Evaluation of Fragmented, Open-Coil, Percutaneous Peripheral Nerve Stimulation Leads.

OBJECTIVE: Percutaneous peripheral nerve stimulation (PNS) is an FDA-cleared pain treatment. Occasionally, fragments of the lead (MicroLead, SPR Therapeutics, LLC, Cleveland, OH, USA) may be retained following lead removal. Since the lead is metallic, there are associated magnetic resonance imaging (MRI) risks. Therefore, the objective of this investigation was to evaluate MRI-related issues (i.e., magnetic field interactions, heating, and artifacts) for various lead fragments. METHODS: Testing was conducted using standardized techniques on lead fragments of different lengths (i.e., 50, 75, and 100% of maximum possible fragment length of 12.7 cm) to determine MRI-related problems. Magnetic field interactions (i.e., translational attraction and torque) and artifacts were tested for the longest lead fragment at 3 Tesla. MRI-related heating was evaluated at 1.5 Tesla/64 MHz and 3 Tesla/128 MHz with each lead fragment placed in a gelled-saline filled phantom. Temperatures were recorded on the lead fragments while using relatively high RF power levels. Artifacts were evaluated using T1-weighted, spin echo, and gradient echo (GRE) pulse sequences. RESULTS: The longest lead fragment produced only minor magnetic field interactions. For the lead fragments evaluated, physiologically inconsequential MRI-related heating occurred at 1.5 Tesla/64 MHz while under certain 3 Tesla/128 MHz conditions, excessive temperature elevations may occur. Artifacts extended approximately 7 mm from the lead fragment on the GRE pulse sequence, suggesting that anatomy located at a position greater than this distance may be visualized on MRI. CONCLUSIONS: MRI may be performed safely in patients with retained lead fragments at 1.5 Tesla using the specific conditions of this study (i.e., MR Conditional). Due to possible excessive temperature rises at 3 Tesla, performing MRI at that field strength is currently inadvisable.

Fully Implantable Peripheral Nerve Stimulation for Hemiplegic Shoulder Pain: A Multi-Site Case Series With Two-Year Follow-Up.

OBJECTIVE: To explore the feasibility and safety of a single-lead, fully implantable peripheral nerve stimulation system for the treatment of chronic shoulder pain in stroke survivors. PARTICIPANTS: Participants with moderate to severe shoulder pain not responsive to conservative therapies for six months. METHODS: During the trial phase, which included a blinded sham introductory period, a percutaneous single-lead peripheral nerve stimulation system was implanted to stimulate the axillary nerve of the affected shoulder. After a three-week successful trial, participants received an implantable pulse generator with an electrode placed to stimulate the axillary nerve of the affected shoulder. Outcomes included pain, pain interference, pain-free external rotation range of motion, quality of life, and safety. Participants were followed for 24 months. RESULTS: Twenty-eight participants underwent trial stimulation and five participants received an implantable pulse generator. The participants who received the implantable generator experienced an improvement in pain severity (p = 0.0002). All five participants experienced a 50% or greater pain reduction at 6 and 12 months, and four experienced at least a 50% reduction at 24 months. There was an improvement in pain interference (p < 0.0001). There was an improvement in pain-free external ROM (p = 0.003). There were no serious adverse events related to the device or to the procedure. CONCLUSIONS: This case series demonstrates the safety and efficacy of a fully implantable axillary PNS system for chronic HSP. Participants experienced reduction in pain, reduction in pain interference, and improved pain-free external rotation ROM. There were no serious adverse events associated with the system or the procedure.

Percutaneous Peripheral Nerve Stimulation for the Treatment of Chronic Low Back Pain: Two Clinical Case Reports of Sustained Pain Relief.

As the leading cause of disability among U.S. adults, chronic low back pain (LBP) is one of the most prevalent and challenging musculoskeletal conditions. Neuromodulation provides an opportunity to reduce or eliminate the use of opioids to treat chronic LBP, but the cost and invasiveness of existing methods have limited its broad adoption, especially earlier in the treatment continuum. The present case report details the results of a novel method of short-term percutaneous peripheral nerve stimulation (PNS) in 2 subjects with chronic LBP. At the end of the 1-month therapy, stimulation was discontinued and the leads were withdrawn. PNS produced clinically significant improvements in pain (62% average reduction in Brief Pain Inventory Question #5, average pain), and functional outcomes (73% reduction in disability, Oswestry Disability Index; 83% reduction in pain interference, Brief Pain Inventory). Both subjects reduced nonopioid analgesic use by 83%, on average, and the one subject taking opioids ceased using all opioids. The only adverse event was minor skin irritation caused by a topical dressing. The clinically significant improvements were sustained at least 4 months after start of therapy (79% average reduction in pain; both reported minimal disability; 100% reduction in opioids; 74% reduction nonopioids). The results reveal the utility of this novel, short-term approach and its potential as a minimally invasive neuromodulation therapy for use earlier in the treatment continuum to produce sustained pain relief and reduce or eliminate the need for analgesic medications, including opioids, as well as more expensive and invasive surgical or therapeutic alternatives.

Neurostimulation for Postsurgical Analgesia: A Novel System Enabling Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation.

While neurostimulation-stimulation of the nervous system using electrical current-has been used to treat chronic pain, its use treating postsurgical pain has been limited. Here, we report on the clinical application of a novel investigational lead to provide analgesia following total knee arthroplasty. In 5 subjects, leads were inserted percutaneously using ultrasound guidance within 0.5 to 3.0 cm of the femoral and/or sciatic nerve(s). With the delivery of current, pain decreased an average of 63% at rest, with 4 of 5 subjects having relief of > 50%. During passive and active knee flexion, pain decreased an average of 14% and 50%, with 0/3 and 1/2 subjects attaining > 50% relief, respectively. Ultrasound-guided percutaneous peripheral nerve stimulation may be a practical modality for the treatment of postsurgical pain.

Infection Rates of Electrical Leads Used for Percutaneous Neurostimulation of the Peripheral Nervous System.

BACKGROUND: Percutaneous neurostimulation of the peripheral nervous system involves the insertion of a wire "lead" through an introducing needle to target a nerve/plexus or a motor point within a muscle. Electrical current may then be passed from an external generator through the skin via the lead for various therapeutic goals, including providing analgesia. With extended use of percutaneous leads sometimes greater than a month, infection is a concern. It was hypothesized that the infection rate of leads with a coiled design is lower than for leads with a noncoiled cylindrical design. METHODS: The literature was retrospectively reviewed for clinical studies of percutaneous neurostimulation of the peripheral nervous system of greater than 2 days that included explicit information on adverse events. The primary endpoint was the number of infections per 1,000 indwelling days. RESULTS: Forty-three studies were identified that met inclusion criteria involving coiled (n = 21) and noncoiled (n = 25) leads (3 studies involved both). The risk of infection with noncoiled leads was estimated to be 25 times greater than with coiled leads (95% confidence interval [CI] 2 to 407, P = 0.006). The infection rates were estimated to be 0.03 (95% CI 0.01 to 0.13) infections per 1,000 indwelling days for coiled leads and 0.83 (95% CI 0.16 to 4.33) infections per 1,000 indwelling days for noncoiled leads (P = 0.006). CONCLUSIONS: Percutaneous leads used for neurostimulation of the peripheral nervous system have a much lower risk of infection with a coiled design compared with noncoiled leads: approximately 1 infection for every 30,000 vs. 1,200 indwelling days, respectively.

Contralaterally Controlled Functional Electrical Stimulation Improves Hand Dexterity in Chronic Hemiparesis: A Randomized Trial.

BACKGROUND AND PURPOSE: It is unknown whether one method of neuromuscular electrical stimulation for poststroke upper limb rehabilitation is more effective than another. Our aim was to compare the effects of contralaterally controlled functional electrical stimulation (CCFES) with cyclic neuromuscular electrical stimulation (cNMES). METHODS: Stroke patients with chronic (>6 months) moderate to severe upper extremity hemiparesis (n=80) were randomized to receive 10 sessions/wk of CCFES- or cNMES-assisted hand opening exercise at home plus 20 sessions of functional task practice in the laboratory for 12 weeks. The task practice for the CCFES group was stimulation assisted. The primary outcome was change in Box and Block Test (BBT) score at 6 months post treatment. Upper extremity Fugl-Meyer and Arm Motor Abilities Test were also measured. RESULTS: At 6 months post treatment, the CCFES group had greater improvement on the BBT, 4.6 (95% confidence interval [CI], 2.2-7.0), than the cNMES group, 1.8 (95% CI, 0.6-3.0), between-group difference of 2.8 (95% CI, 0.1-5.5), P=0.045. No significant between-group difference was found for the upper extremity Fugl-Meyer (P=0.888) or Arm Motor Abilities Test (P=0.096). Participants who had the largest improvements on BBT were <2 years post stroke with moderate (ie, not severe) hand impairment at baseline. Among these, the 6-month post-treatment BBT gains of the CCFES group, 9.6 (95% CI, 5.6-13.6), were greater than those of the cNMES group, 4.1 (95% CI, 1.7-6.5), between-group difference of 5.5 (95% CI, 0.8-10.2), P=0.023. CONCLUSIONS: CCFES improved hand dexterity more than cNMES in chronic stroke survivors. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00891319.

Percutaneous peripheral nerve stimulation for chronic pain in subacromial impingement syndrome: a case series.

OBJECTIVE: The objective of this study was to determine the effect of peripheral nerve stimulation (PNS) on pain reduction for those with refractory subacromial impingement syndrome (SIS) and to evaluate the association with reduced disability, impairment, and safety. Our hypotheses are that PNS will be associated with a reduction in pain, impairment and disability, and improvement in quality of life while demonstrating safety. MATERIAL AND METHODS: Adults with shoulder pain of at least six months duration were recruited for a three-week treatment of percutaneous PNS applied through a percutaneous electrode to the axillary motor points of the deltoid muscle. Subjects were followed for 12 weeks after treatment. The primary outcome was the worst pain in the last week, and secondary outcomes included pain interference, the Disabilities of the Arm, Shoulder, and Hand questionnaire, shoulder abduction range of motion, and safety. Analysis was with a linear mixed model. RESULTS: Ten subjects were recruited. Longitudinal analysis demonstrated significant reduction in pain relative to baseline (F(1, 66) = 12.9, p < 0.01). After correcting for multiple comparisons, there were significant reductions at explantation and all follow-up time points when compared with baseline. There were also significant improvements in pain interference (F(1,65) = 15.0, p < 0.01), the Disabilities of the Arm, Shoulder, and Hand questionnaire (F(1,35) = 7.0, p = 0.01), and shoulder abduction range of motion (F(1,35) = 6.3, p = 0.02). CONCLUSION: Intramuscular PNS for chronic shoulder pain due to SIS is a safe treatment associated with pain reduction, lower pain interference with activities of daily living, reduced disability, and improved shoulder abduction. Pain reduction is maintained for at least 12 weeks after treatment.

Innovations in Stroke Recovery and Rehabilitation: Poststroke Pain.

Pain can be a significant barrier to a stroke survivors' functional recovery and can also lead to a decreased quality of life. Common pain conditions after stroke include headache, musculoskeletal pain, spasticity-related pain, complex regional pain syndrome, and central poststroke pain. This review investigates the evidence of diagnostic and management guidelines for various pain syndromes after stroke and identifies opportunities for future research to advance the field of poststroke pain.

The Endoscopic Lateral Transorbital Approach for the Removal of Select Sphenoid Wing and Middle Fossa Meningiomas. Surgical Technique and Short-Term Outcomes.

BACKGROUND AND OBJECTIVE: The endoscopic lateral transorbital approach (eLTOA) is a relatively new approach to the skull base that has only recently been applied in vivo in the management of complex skull base pathology. Most meningiomas removed with this approach have been in the spheno-orbital location. We present a series of select purely sphenoid wing and middle fossa meningiomas removed through eLTOA. The objective here was to describe the selection criteria and results of eLTOA for a subset of sphenoid wing and middle fossa meningiomas. METHODS: This is a retrospective study based on a prospectively maintained database of consecutive cases of eLTOA operated on at our institution by the lead author. The cohort's clinical and radiographic characteristics and outcome are presented. RESULTS: Five patients underwent eLTOA to remove 3 sphenoid wing and 2 middle fossa meningiomas. The mean tumor volume was 11.9 cm 3 . Gross total resection was achieved in all cases. There were no intraoperative complications. Postoperatively, there was one case of subretinal hemorrhage, which was corrected by open vitrectomy repair, and one case of cerebrospinal fluid leak, which resolved with lumbar drainage. Three patients presented with visual impairment, 1 improved, 1 remained stable, and 1 worsened, but returned to stable after vitrectomy repair. All patients have been free of disease at a median follow-up of 8.9 months. CONCLUSION: eLTOA provides a direct minimal access corridor to certain well-selected sphenoid wing and middle fossa meningiomas. eLTOA minimizes brain retraction and provides a high rate of gross total resection. Meningiomas appropriately selected based on size, type, and location of dural attachment, and the eLTOA is a safe, rapid, and highly effective procedure with acceptable morbidity.

A review of prospective studies regarding percutaneous peripheral nerve stimulation treatment in the management of chronic pain.

Conventionally, peripheral nerve stimulation (PNS) for treatment of chronic pain has involved a two-stage process: a short-term (e.g., 7 days) trial and, if significant pain relief is achieved, a permanent PNS system is implanted. A percutaneous PNS treatment is now available where a coiled lead may be implanted for up to 60 days with the goal of producing sustained relief. In the present review, published prospective trials using percutaneous PNS treatment were identified and synthesized. The collected evidence indicates that percutaneous PNS treatment for up to 60 days provides durable clinically significant improvements in pain and pain interference. Similar efficacy across diverse targets and etiologies supports the broad applicability for use within the chronic pain population using this nonopioid technology.

What is this review about? This review looks at a drug-free way to treat chronic pain called percutaneous peripheral nerve stimulation (PNS). Percutaneous means it is placed through the skin. PNS applies small amounts of electricity to the nerves to reduce chronic pain. Most PNS systems involve a two-step process. A short trial is first performed to see if a patient has pain relief. A permanent system is then placed if the person had pain relief. Percutaneous PNS treatments are different. They use a thin wire called a lead placed in the body for up to 60 days. The lead is taken out at the end of the treatment period. Studies have shown that this type of PNS treatment can reduce chronic pain even after the treatment is over. No previous article has collected all these studies of percutaneous PNS in one place.What evidence was gathered? This review found evidence from studies on treatment of chronic pain. Pain types included shoulder pain, neuropathic pain and low back pain. It found that percutaneous PNS treatment for up to 60 days can reduce pain and how pain interferes with daily life.How can these data lead to better care for patients? These findings mean that percutaneous PNS treatments could be a useful, non-drug option for many types of chronic pain.

First-In-Human Demonstration of High Frequency Electrical Motor Nerve Block: Case Report.

ABSTRACT: This feasibility study tested the capability of high frequency stimulation (HFS) to block muscle contractions elicited by electrical stimulation of the same nerve proximally. During a tendon lengthening surgery in the forearm, the anterior interosseous nerve (AIN) was exposed. A specialized nerve cuff electrode was placed around the nerve, and a stimulating probe held on the nerve 1 cm proximal to the cuff electrode delivered pulses of current causing the pronator quadratus muscle to contract. Through the cuff electrode, 20 kHz HFS was delivered to the nerve for 10 seconds during proximal stimulation. HFS amplitudes between 5 and 10 mA peak-to-peak were tested to determine which produced complete and partial block of the electrically induced contractions. The minimum HFS amplitude that produced complete block was 8 mA, with lower amplitudes producing partial block. In all trials, muscle contractions resumed immediately after HFS was turned off. This demonstration of high frequency electrical nerve block is a milestone in the road to clinical implementation of HFS mediated motor block for spasticity.

Randomized controlled trial of surface peroneal nerve stimulation for motor relearning in lower limb hemiparesis.

OBJECTIVE: To compare the motor relearning effect of a surface peroneal nerve stimulator (PNS) versus usual care on lower limb motor impairment, activity limitation, and quality of life among chronic stroke survivors. DESIGN: Single-blinded randomized controlled trial. SETTING: Teaching hospital of academic medical center. PARTICIPANTS: Chronic stroke survivors (N=110; >12wk poststroke) with unilateral hemiparesis and dorsiflexion strength of ≤4/5 on the Medical Research Council scale. INTERVENTIONS: Subjects were stratified by motor impairment level and then randomly assigned to ambulation training with either a surface PNS device or usual care (ankle-foot orthosis or no device) intervention. Subjects were treated for 12 weeks and followed up for 6 months posttreatment. MAIN OUTCOME MEASURES: Lower limb portion of the Fugl-Meyer (FM) Assessment (motor impairment), the modified Emory Functional Ambulation Profile (mEFAP) performed without a device (functional ambulation), and the Stroke Specific Quality of Life (SSQOL) scale. RESULTS: There was no significant treatment group main effect or treatment group by time interaction effect on FM, mEFAP, or SSQOL raw scores (P>.05). The time effect was significant for the 3 raw scores (P<.05). However, when comparing average change scores from baseline (t1) to end of treatment (t2, 12wk), and at 12 weeks (t3) and 24 weeks (t4) after end of treatment, significant differences were noted only for the mEFAP and SSQOL scores. The change in the average scores for both mEFAP and SSQOL occurred between t1 and t2, followed by relative stability thereafter. CONCLUSIONS: There was no evidence of a motor relearning effect on lower limb motor impairment in either the PNS or usual-care groups. However, both the PNS and usual-care groups demonstrated significant improvements in functional mobility and quality of life during the treatment period, which were maintained at 6-month follow-up.

Single-lead percutaneous peripheral nerve stimulation for the treatment of hemiplegic shoulder pain: a case series.

OBJECTIVE: Previous studies demonstrated the efficacy of Intramuscular Nerve (IMN) therapy with a 4-lead percutaneous, peripheral nerve stimulation (PNS) system in reducing hemiplegic shoulder pain (HSP). This case series investigates the feasibility of a less complex, single-lead approach in reducing HSP. METHODS: Eight participants received one percutaneous intramuscular lead in the hemiparetic deltoid muscle and were then treated 6 hours/day for 3 weeks. The primary outcome measure was the Brief Pain Inventory (Short-Form) Question 3 (BPI3), which queries worst pain in the last week on a 0 to 10 numeric rating scale. Secondary outcomes included pain interference (BPI9) and Medical Outcomes Study Short-Form 36 (SF-36v2). Primary and secondary outcomes were assessed at the end of treatment (EOT) and 1 and 4 weeks after the EOT. RESULTS: All participants tolerated the treatment well with 96% compliance. All leads remained infection-free and were removed intact at the EOT. On average, participants exhibited 70% reduction in BPI3 at the EOT and 61% reduction at 4 weeks after the EOT. All participants satisfied the success criterion of at least a 2-point reduction in BPI3 at the EOT. Longitudinal analysis revealed significant treatment effect for BPI3 (F = 14.0, P < 0.001), BPI9 (F = 5.9, P < 0.01), and the bodily pain domain of SF-36v2 (F = 12.8, P < 0.001). CONCLUSION: This case series demonstrates the feasibility of a single-lead, 3-week IMN therapy for the treatment of chronic HSP. Additional studies are needed to further demonstrate safety, efficacy, and long-term benefit, define optimal prescriptive parameters and dose, and expand clinical indications.

Intraoperative occipital to C2 angle and external acoustic meatus-to-axis angular measurements for optimizing alignment during posterior fossa decompression and occipitocervical fusion for complex Chiari malformation.

Background: Excess flexion or extension during occipitocervical fusion (OCF) can lead to postoperative complications, such as dysphagia, respiratory problems, line of sight issues, and neck pain, but posterior fossa decompression (PFD) and OCF require different positions that require intraoperative manipulation. Objective: The objective of this study was to describe quantitative fluoroscopic morphometrics in Chiari malformation (CM) patients with symptoms of craniocervical instability (CCI) and demonstrate the intraoperative application of these measurements to achieve neutral craniocervical alignment while leveraging a single axis of motion with the Mayfield head clamp locking mechanism. Methods: A retrospective cohort study of patients with CM 1 and 1.5 and features of CCI who underwent PFD and OCF at a single-center institution from March 2015 to October 2020 was performed. Patient demographics, preoperative presentation, radiographic morphometrics, operative details, complications, and clinical outcomes were analyzed. Results: A total of 39 patients met the inclusion criteria, of which 37 patients (94.9%) did not require additional revision surgery after PFD and OCF. In this nonrevision cohort, preoperative to postoperative occipital to C2 angle (O-C2a) (13.5° ± 10.4° vs. 17.5° ± 10.1°, P = 0.047) and narrowest oropharyngeal airway space (nPAS) (10.9 ± 3.4 mm vs. 13.1 ± 4.8 mm, P = 0.007) increased significantly. These measurements were decreased in the two patients who required revision surgery due to postoperative dysphagia (mean difference - 16.6°° in O C2a and 12.8°° in occipital and external acoustic meatus to axis angle). Based on these results, these fluoroscopic morphometrics are intraoperatively assessed, utilizing a locking Mayfield head clamp repositioning maneuver to optimize craniocervical alignment prior to rod placement from the occipital plate to cervical screws. Conclusion: Establishing a preoperative baseline of reliable fluoroscopic morphometrics can guide surgeons intraoperatively in appropriate patient realignment during combined PFD and OCF, and may prevent postoperative complications.