Thumb Carpometacarpal Joint Denervation for Early Osteoarthritis: An Overview of the Literature and a Pilot Study on Pain Reduction and Patient Satisfaction

Background  The treatment of patients with osteoarthritis of the first carpometacarpal joint (CMC-I) aims at pain reduction to improve hand function and quality of life. The CMC-I denervation procedure is relatively new and seems appealing, as it is minimally invasive and has few or no disadvantages. To date, however, little research has been done on the results of a CMC-I denervation. The aim of this study was to investigate whether denervation provides pain reduction in patients with early CMC-I osteoarthritis. Methods  A literature search was done using PubMed. Studies were excluded if access to full text was not available, if the articles were written in other languages than Dutch or English, and if preoperative testing, follow-up testing, or reporting were incomplete. Studies were included if patients were older than 18 years, had primary CMC-I osteoarthritis with no other wrist pathology, and had received conservative treatment without sustained benefit. The Critical Appraisal Tools of the Joanna Briggs Institute were used for critical appraisal. Clinical data was gathered retrospectively from the medical records to identify patients who underwent CMC-I denervation in The Hand Clinic, Amsterdam. The data of 20 patients were analyzed. Pre- and postoperative visual analog scale (VAS) scores on pain, patient satisfaction, and complications were evaluated. Patients older than 18 years with primary CMC-I osteoarthritis stage I and II and no other wrist pathology, in whom conservative treatment failed were included in the study. Patients with CMC-I osteoarthritis stage III and IV were excluded. Results  All 17 search results were screened for full text access, after which 6 case series, 4 systematic reviews, 1 cohort study, 1 comment, and 1 scoping review was included. All but one study showed pain reduction after surgery. In half of the studies, this difference was statistically significant. The average patient satisfaction in these studies was 84.1% and the complication rate was 13.4%. A total of 20 patients were included between 2019 and 2022, with a mean preoperative VAS for pain at rest of 48.2 ± 29.9. After surgery, this decreased to 35.8 ± 34.1. This difference was not statistically significant. The mean VAS for pain during use before denervation was 79 ± 18.4 and this decreased to 49.8 ± 34.2 postoperatively. This difference did appear to be statistically significant. The average patient satisfaction was 60%, and the complication rate was 10%. Conclusion  This study provides a literature overview and a pilot study on pain reduction, patient satisfaction, and complications after denervation of the CMC-I joint in patients with early osteoarthritis. Our retrospective case series roughly mirrored the average results found in the literature. There was a statistically significant decrease in pain during use postoperatively. There was no statistically significant difference in pain at rest before and after surgery. The complications were mild and the complication rate was low; however, the average patient satisfaction rate was lower as compared to that reported in the literature.

Renal Denervation for the Treatment of Hypertension: A Scientific Statement From the American Heart Association

Hypertension is a leading risk factor for cardiovascular morbidity and mortality. Despite the widespread availability of both pharmacological and lifestyle therapeutic options, blood pressure control rates across the globe are worsening. In fact, only 23% of individuals with high blood pressure in the United States achieve treatment goals. In 2023, the US Food and Drug Administration approved renal denervation, a catheter-based procedure that ablates the renal sympathetic nerves, as an adjunctive treatment for patients in whom lifestyle modifications and antihypertensive medications do not adequately control blood pressure. This approval followed the publication of multiple randomized clinical studies using rigorous trial designs, all incorporating renal angiogram as the sham control. Most but not all of the new generation of trials reached their primary end point, demonstrating modest efficacy of renal denervation in lowering blood pressure across a spectrum of hypertension, from mild to truly resistant. Individual patient responses vary, and further research is needed to identify those who may benefit most. The initial safety profile appears favorable, and multiple ongoing studies are assessing longer-term efficacy and safety. Multidisciplinary teams that include hypertension specialists and adequately trained proceduralists are crucial to ensure that referrals are made appropriately with full consideration of the potential risks and benefits. Incorporating patient preferences and engaging in shared decision-making conversations will help patients make the best decisions given their individual circumstances. Although further research is clearly needed, renal denervation presents a novel treatment strategy for patients with uncontrolled blood pressure.

Tracheobronchial injury after blunt thoracic trauma-lessons to learn in diagnosis, treatment, and postoperative care: a case series

Background

Tracheobronchial injury (TBI) is the subsuming term to describe rare and mostly traumatic damage to the tracheobronchial tree. Prehospital mortality is significant. TBI patients may face delayed diagnosis, challenging perioperative care, and prolonged recovery. The focus of this case series is to identify issues that represent common hurdles and potential problems in the diagnosis, treatment, and postoperative care of patients with TBI.

Case Description

This is a single-center retrospective case-series study of four patients who experienced TBI following blunt thoracic trauma in the study period from January 1, 2020, to December 31, 2023. The mean age of the patients was 48 years, with patient age ranging from 24 to 59 years. One patient was female and the other three were male. Two patients sustained injuries to the main bronchi, while the others sustained injuries to more peripheral parts of the tracheobronchial tree. Three patients were secondary transfers to our hospital, while the other was a primary admission. All four patients underwent surgery for their TBI. The duration of hospitalization ranged from 10 to 60 days. The two patients with main stem bronchus injury required the longest hospitalization. The same two patients required extracorporeal membrane oxygenation therapy. We experienced no mortality, and all patients were discharged for post-hospital rehabilitation.

Conclusions

TBI management requires a multidisciplinary and experienced team. One must be aware of the classic clinical presentation: dyspnea, soft tissue emphysema, and hemoptysis. Cases in which a history of trauma is associated with dyspnea and/or chest wall/mediastinal emphysema require early bronchoscopy as the diagnostic gold standard. The use of "Minimum-intensity projection" (MinIP) reconstructions can help identify TBI in computed tomography scans. Extracorporeal membrane oxygenation therapy is to be considered in selected cases. Surgical repair must focus on preventing parenchymal loss by reconstructing the bronchial defect while avoiding anatomical resection. Postoperative care should consider the possibility of bronchial denervation and its potential complications.

Efficacy and Safety of Catheter-Based Radiofrequency Renal Denervation in Chinese Patients With Uncontrolled Hypertension: The Randomized, Sham-Controlled, Multi-Center Iberis-HTN Trial

BACKGROUND

Renal denervation (RDN) can lower blood pressure (BP) in patients with hypertension in both the presence and absence of medication. This is the first sham-controlled trial investigating the safety and efficacy of RDN in China.

METHODS

This prospective, multicenter, randomized, patient- and outcome-assessor-blinded, sham-controlled trial investigated radiofrequency RDN in patients with hypertension on standardized triple antihypertensive therapy. Eligible patients were randomized 1:1 to undergo RDN using a multi-electrode radiofrequency catheter (Iberis; AngioCare, Shanghai, China) or a sham procedure. The primary efficacy outcome was the between-group difference in baseline-adjusted change in mean 24-hour ambulatory systolic BP from randomization to 6 months.

RESULTS

Of 217 randomized patients (mean age, 45.3±10.2 years; 21% female), 107 were randomized to RDN and 110 were randomized to sham control. At 6 months, there was a greater reduction in 24-hour systolic BP in the RDN (-13.0±12.1 mm Hg) compared with the sham control group (-3.0±13.0 mm Hg; baseline-adjusted between-group difference, -9.4 mm Hg [95% CI, -12.8 to -5.9]; P<0.001). Compared with sham, 24-hour diastolic BP was lowered by -5.0 mm Hg ([95% CI, -7.5 to -2.4]; P<0.001) 6 months after RDN, and office systolic and diastolic BP was lowered by -6.4 mm Hg ([95% CI, -10.5 to -2.3]; P=0.003) and -5.1 mm Hg ([95% CI, -8.2 to -2.0]; P=0.001), respectively. One patient in the RDN group experienced an access site complication (hematoma), which resolved without sequelae. No other major device- or procedure-related safety events occurred through follow-up.

CONCLUSIONS

In this trial of Chinese patients with uncontrolled hypertension on a standardized triple pharmacotherapy, RDN was safe and reduced ambulatory and office BP at 6 months compared with sham.

REGISTRATION

URL: https://clinicaltrials.gov; Unique identifier: NCT02901704.

Reduced osseointegration in disuse and denervation rat models results from impaired cellular responses to multiscale microstructured titanium surfaces

Immobilization-induced skeletal unloading results in muscle atrophy and rapid bone loss, thereby increasing the risk of falling and the need for implant therapy in patients with extended bed rest or neuromuscular injuries. Skeletal unloading causes bone loss by altering bone growth and resorption, suggesting that implant performance might be affected. To test this, we focused on early events in implant osseointegration. We used the rat sciatic neurectomy-induced disuse model under two different settings. In Study 1, 16 Sprague Dawley rats (SD) were separated into control, sham operated+cast immobilization, and sciatic neurectomy+casting groups; titanium implants with multiscale microtextured topography and hydrophilic chemistry (modSLA) were inserted in the distal femoral metaphysis. Neurectomy surgeries and casting were performed at the same surgical setting as implant placement; rats were euthanized 4 weeks post-implantation. In Study 2, we established the unloaded condition before implantation. A total of 12 SD rats were divided into control and sciatic+femoral neurectomy groups. A total of 24 days after sciatic and femoral neurectomy surgery, rats received implants. Study 2 rats were euthanized at 4 weeks post-implantation. MicroCT and histomorphometry showed that trabecular bone and osseointegration were reduced when disuse was established before implantation. Osteoblasts isolated from Study 1 sciatic neurectomy tibial bones exhibited impaired differentiation on modSLA culture disks, revealing a possible mechanism responsible for the decreased osseointegration observed in the Study 2 rats. This study addressed the importance of considering the mechanical unloading and muscle function history before implant insertion and suggests that implant performance was reduced due to poor cellular ability to regenerate.

Muscle Atrophy and mRNA-miRNA Network Analysis of Vascular Endothelial Growth Factor (VEGF) in a Mouse Model of Denervation-Induced Disuse

BACKGROUND

Skeletal muscle atrophy is frequently caused by the disuse of muscles. It impacts quality of life, especially in aging populations and those with chronic diseases. Understanding the molecular mechanisms underlying muscle atrophy is crucial for developing effective therapies.

OBJECTIVE

To investigate the roles of vascular endothelial growth factor (VEGF) and various microRNAs (miRNAs) in muscle atrophy using a mouse model of denervation (DEN)-induced disuse, and to elucidate their interactions and regulatory functions through comprehensive network analysis.

METHODS

The right sciatic nerve of C57BL/6J mice (n=6) was excised to simulate DEN, with the left serving as a sham surgery control (Sham). Following a two-week period, wet muscle weight was measured. Total RNA was extracted from the tibialis anterior muscle for microarray analysis. Significant expression changes were analyzed via Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and miRNet for miRNAs.

RESULTS

Denervated limbs showed a significant reduction in muscle weight. Over 1,000 genes displayed increased expression, while 527 showed reductions to less than half of control levels. VEGF, along with specific miRNAs such as miR-106a-5p, miR-mir20a-5p, mir93-5p and mir17-5p, occupied central regulatory nodes within the gene network. Functional analysis revealed that these molecules are involved in key biological processes including regulation of cell migration, vasculature development, and regulation of endothelial cell proliferation. The increased miRNAs were subjected to further network analysis that revealed significant regulatory interactions with target mRNAs.

CONCLUSION

VEGF and miRNAs play crucial roles in the progression of skeletal muscle atrophy, offering potential targets for therapeutic interventions aimed at reducing atrophy and enhancing muscle regeneration.

A molecular pathway for cancer cachexia-induced muscle atrophy revealed at single-nucleus resolution

Cancer cachexia is a prevalent and often fatal wasting condition that cannot be fully reversed with nutritional interventions. Muscle atrophy is a central component of the syndrome, but the mechanisms whereby cancer leads to skeletal muscle atrophy are not well understood. We performed single-nucleus multi-omics on skeletal muscles from a mouse model of cancer cachexia and profiled the molecular changes in cachexic muscle. Our results revealed the activation of a denervation-dependent gene program that upregulates the transcription factor myogenin. Further studies showed that a myogenin-myostatin pathway promotes muscle atrophy in response to cancer cachexia. Short hairpin RNA inhibition of myogenin or inhibition of myostatin through overexpression of its endogenous inhibitor follistatin prevented cancer cachexia-induced muscle atrophy in mice. Our findings uncover a molecular basis of muscle atrophy associated with cancer cachexia and highlight potential therapeutic targets for this disorder.

Randomized Trials of Renal Denervation for Uncontrolled Hypertension: An Updated Meta-Analysis

BACKGROUND

Despite optimal medical therapy, a significant proportion of patients' blood pressure remains uncontrolled. Catheter-based renal denervation (RDN) has been proposed as a potential intervention for uncontrolled hypertension. We conducted an updated meta-analysis to assess the efficacy and safety of RDN in patients with uncontrolled hypertension, with emphasis on the differential effect of RDN in patients on and off antihypertensive medications.

METHODS AND RESULTS

Online databases were searched to identify randomized clinical trials comparing efficacy and safety of RDN versus control in patients with uncontrolled hypertension. Subgroup analyses were conducted for sham-controlled trials and studies that used RDN devices that have gained or are currently seeking US Food and Drug Administration approval. Fifteen trials with 2581 patients (RDN, 1723; sham, 858) were included. In patients off antihypertensive medications undergoing RDN, a significant reduction in 24-hour ambulatory (-3.70 [95% CI, -5.41 to -2.00] mm Hg), office (-4.76 [95% CI, -7.57 to -1.94] mm Hg), and home (-3.28 [95% CI, -5.96 to -0.61] mm Hg) systolic blood pressures was noted. In patients on antihypertensive medications, a significant reduction was observed in 24-hour ambulatory (-2.23 [95% CI, -3.56 to -0.90] mm Hg), office (-6.39 [95% CI, -11.49 to -1.30]), home (-6.08 [95% CI, -11.54 to -0.61] mm Hg), daytime (-2.62 [95% CI, -4.14 to -1.11]), and nighttime (-2.70 [95% CI, -5.13 to -0.27]) systolic blood pressures, as well as 24-hour ambulatory (-1.16 [95% CI, -1.96 to -0.35]), office (-3.17 [95% CI, -5.54 to -0.80]), and daytime (-1.47 [95% CI, -2.50 to -0.27]) diastolic blood pressures.

CONCLUSIONS

RDN significantly lowers blood pressure in patients with uncontrolled hypertension, in patients off and on antihypertensive medications, with a favorable safety profile. The efficacy of RDN was consistent in sham-controlled trials and contemporary trials using US Food and Drug Administration-approved devices.

Nonpharmacological Approaches to Managing Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a common subtype of heart failure marked by impaired left ventricular diastolic function and decreased myocardial compliance. Given the limited availability of evidence-based pharmacological treatments for HFpEF, there is a growing interest in nonpharmacological interventions as viable therapeutic alternatives. This review aims to explore the pathophysiology of HFpEF and present recent advancements in nonpharmacological management approaches, encompassing noninvasive therapies, invasive procedures and targeted treatments for comorbidities. An extensive literature review was undertaken to identify and synthesize emerging nonpharmacological treatment options for HFpEF, assessing their potential to enhance patient outcomes. Nonpharmacological strategies, such as vagus nerve stimulation, percutaneous pulmonary artery denervation, renal denervation, transcatheter insertion of atrial shunts and pericardial resection, demonstrate promising potential for alleviating HFpEF symptoms and improving patient prognosis. Moreover, addressing comorbidities, such as hypertension and diabetes, may offer additional therapeutic benefits. These cutting-edge techniques, in conjunction with well-established exercise therapies, pave the way for future research and clinical applications in the field. Nonpharmacological interventions hold promise for advancing HFpEF patient care and fostering a deeper understanding of these treatment approaches, which will facilitate new clinical applications and contribute to the development of more targeted therapies.

Myositis and Its Mimics: Guideline Updates, MRI Characteristics, and New Horizons

Myositis is defined as inflammation within skeletal muscle and is a subcategory of myopathy, which is more broadly defined as any disorder affecting skeletal muscle. Myositis may be encountered as a component of autoimmune and connective tissue diseases, where it is described as idiopathic inflammatory myopathy (IIM). Myositis can also be caused by infections as well as toxins and drugs, including newer classes of medications. MRI plays an important role in the diagnosis and evaluation of patients with suspected myositis, but many entities may have imaging features similar to those of myositis and can be considered myositis mimics. These include muscular dystrophies, denervation, deep venous thrombosis, diabetic myonecrosis, muscle injury, heterotopic ossification, and even neoplasms. In patients with suspected myositis, definitive diagnosis may require integrated analysis of imaging findings with clinical, laboratory, and pathology data. The objectives of this article are to review the fundamental features of myositis, including recent updates in terminology and consensus guidelines for IIMs; the most important MRI differential diagnostic considerations for myositis (i.e., myositis mimics); and new horizons, including the potential importance of artificial intelligence and multimodal integrated diagnostics in the evaluation of patients with muscle disorders.

RBP4 promotes denervation-induced muscle atrophy through STRA6-dependent pathway

BACKGROUNDS

Fat infiltration of skeletal muscle has been recognized as a common feature of many degenerative muscle disorders. Retinol binding protein 4 (RBP4) is an adipokine that has been demonstrated to be correlated with the presence and severity of sarcopenia in the elderly. However, the exact role and the underlying mechanism of RBP4 in muscle atrophy remains unclear.

METHODS

Denervation-induced muscle atrophy model was constructed in wild-type and RBP4 knockout mice. To modify the expression of RBP4, mice were received intramuscular injection of retinol-free RBP4 (apo-RBP4), retinol-bound RBP4 (holo-RBP4) or oral gavage of RBP4 inhibitor A1120. Holo-RBP4-stimulated C2C12 myotubes were treated with siRNAs or specific inhibitors targeting signalling receptor and transporter of retinol 6 (STRA6)/Janus kinase 2 (JAK2)/Signal transducer and activator of transcription 3 (STAT3) pathway. Fat accumulation, myofibre cross-sectional area, myotube diameter and the expression of muscle atrophy markers and myogenesis markers were analysed.

RESULTS

The expression levels of RBP4 in skeletal muscles were significantly up-regulated more than 2-fold from 7 days and sustained for 28 days after denervation. Immunofluorescence analysis indicated that increased RBP4 was localized in the infiltrated fatty region in denervated skeletal muscles. Knockout of RBP4 alleviated denervation-induced fatty infiltration and muscle atrophy together with decreased expression of atrophy marker Atrogin-1 and MuRF1 as well as increased expression of myogenesis regulators MyoD and MyoG. By contrast, injection of retinol-bound holo-RBP4 aggregated denervation-induced ectopic fat accumulation and muscle atrophy. Consistently, holo-RBP4 stimulation also had a dose-dependent effect on the reduction of C2C12 myotube diameter and myofibre cross-sectional area, as well as on the increase of Atrogin-1and MuRF1 expression and decrease of MyoD and MyoG expression. Mechanistically, holo-RBP4 treatment increased the expression of its membrane receptor STRA6 (>3-fold) and promoted the phosphorylation of downstream JAK2 and STAT3. Inhibition of STRA6/JAK2/STAT3 pathway either by specific siRNAs or inhibitors could decrease the expression of Atrogin-1 and MuRF1 (>50%) and decrease the expression of MyoD and MyoG (>3-fold) in holo-RBP4-treated C2C12 myotube. RBP4 specific pharmacological antagonist A1120 significantly inhibited the activation of STRA6/JAK2/STAT3 pathway, ameliorated ectopic fat infiltration and protected against denervation-induced muscle atrophy (30% increased myofibre cross-sectional area) in mice.

CONCLUSIONS

In conclusion, our data reveal that RBP4 promotes fat infiltration and muscle atrophy through a STRA6-dependent and JAK2/STAT3 pathway-mediated mechanism in denervated skeletal muscle. Our results suggest that lowering RBP4 levels might serve as a promising therapeutic approach for prevention and treatment of muscle atrophy.

Dystrophin S3059 phosphorylation partially attenuates denervation atrophy in mouse tibialis anterior muscles

The dystrophin protein has well-characterized roles in force transmission and maintaining membrane integrity during muscle contraction. Studies have reported decreased expression of dystrophin in atrophying muscles during wasting conditions, and that restoration of dystrophin can attenuate atrophy, suggesting a role in maintaining muscle mass. Phosphorylation of S3059 within the cysteine-rich region of dystrophin enhances binding between dystrophin and β-dystroglycan, and mimicking phosphorylation at this site by site-directed mutagenesis attenuates myotube atrophy in vitro. To determine whether dystrophin phosphorylation can attenuate muscle wasting in vivo, CRISPR-Cas9 was used to generate mice with whole body mutations of S3059 to either alanine (DmdS3059A) or glutamate (DmdS3059E), to mimic a loss of, or constitutive phosphorylation of S3059, on all endogenous dystrophin isoforms, respectively. Sciatic nerve transection was performed on these mice to determine whether phosphorylation of dystrophin S3059 could attenuate denervation atrophy. At 14 days post denervation, atrophy of tibialis anterior (TA) but not gastrocnemius or soleus muscles, was partially attenuated in DmdS3059E mice relative to WT mice. Attenuation of atrophy was associated with increased expression of β-dystroglycan in TA muscles of DmdS3059E mice. Dystrophin S3059 phosphorylation can partially attenuate denervation-induced atrophy, but may have more significant impact in less severe modes of muscle wasting.

Facial Aberrant Reinnervation Syndrome Following Facial Nerve Injury and Recovery

A common sequela of peripheral nerve injury is aberrant regeneration and recovery. Aberrant regeneration of injured motor nerves can affect all aspects of the nerve circuit from the motor cortex to the target muscle. A more comprehensive term for the symptoms that develop after aberrant motor neuromuscular reinnervation is aberrant reinnervation syndrome (ARS). Injury to the facial nerve followed by aberrant reinnervation results in a spectrum of symptoms that has been called many things in the literature. The authors support that this commonly encountered sequela of facial nerve injury be called facial aberrant reinnervation syndrome (FARS), a term that is more descriptive of the underlying pathophysiology and more inclusive of the clinical symptoms: facial synkinesis, facial muscle hypertonicity, and facial muscle spasm/twitching, which occur following facial nerve injury and recovery. In the following article, we present the clinical manifestations and sequelae of facial nerve injury and recovery and briefly discuss our evolving understanding of the pathophysiology and treatment of FARS.

Effect of Alcohol-Mediated Renal Denervation on Blood Pressure in the Presence of Antihypertensive Medications: Primary Results From the TARGET BP I Randomized Clinical Trial

BACKGROUND

Renal denervation (RDN) has demonstrated clinically relevant reductions in blood pressure (BP) among individuals with uncontrolled hypertension despite lifestyle intervention and medications. The safety and effectiveness of alcohol-mediated RDN have not been formally studied in this indication.

METHODS

TARGET BP I is a prospective, international, sham-controlled, randomized, patient- and assessor-blinded trial investigating the safety and efficacy of alcohol-mediated RDN. Patients with office systolic BP (SBP) ≥150 and ≤180 mm Hg, office diastolic BP ≥90 mm Hg, and mean 24-hour ambulatory SBP ≥135 and ≤170 mm Hg despite prescription of 2 to 5 antihypertensive medications were enrolled. The primary end point was the baseline-adjusted change in mean 24-hour ambulatory SBP 3 months after the procedure. Secondary end points included mean between-group differences in office and ambulatory BP at additional time points.

RESULTS

Among 301 patients randomized 1:1 to RDN or sham control, RDN was associated with a significant reduction in 24-hour ambulatory SBP at 3 months (mean±SD, -10.0±14.2 mm Hg versus -6.8±12.1 mm Hg; treatment difference, -3.2 mm Hg [95% CI, -6.3 to 0.0]; P=0.0487). Subgroup analysis of the primary end point revealed no significant interaction across predefined subgroups. At 3 months, the mean change in office SBP was -12.7±18.3 and -9.7±17.3 mm Hg (difference, -3.0 [95% CI, -7.0 to 1.0]; P=0.173) for RDN and sham, respectively. No significant differences in ambulatory or office diastolic BP were observed. Adverse safety events through 6 months were uncommon, with one instance of accessory renal artery dissection in the RDN group (0.7%). No significant between-group differences in medication changes or patient adherence were identified.

CONCLUSIONS

Alcohol-mediated RDN was associated with a modest but statistically significant reduction in 24-hour ambulatory SBP compared with sham control. No significant differences between groups in office BP or 6-month major adverse events were observed.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02910414.

Redundant nerve roots on magnetic resonance imaging can predict ongoing denervation in patients with lumbar spinal stenosis

INTRODUCTION/AIMS

Redundant nerve roots (RNRs) are abnormally elongated and tortuous nerve roots that develop secondary to degenerative spinal stenosis. RNRs have been associated with poorer clinical outcomes after decompression surgery; however, studies on their clinical characteristics are limited. This study aimed to investigate the association between RNRs and denervation potentials, that is, abnormal spontaneous activity (ASA), on electromyography.

METHODS

We retrospectively reviewed data of patients who underwent an electrodiagnostic study of the lower extremities between January 2020 and March 2023. Of these, patients with lumbar central spinal stenosis, as seen on magnetic resonance imaging, were included. We analyzed clinical and imaging data, including presence of ASA, and compared them according to the presence of RNRs. Multivariable logistic regression analysis was employed to identify factors associated with development of ASA.

RESULTS

Among the 2003 patients screened, 193 were included in the study. RNRs were associated with advanced age (p < .001), longer symptom duration (p = .009), smaller cross-sectional area of the dural sac at the stenotic level (p < .001), and higher frequency of ASA (p < .001). Higher probability of ASA was correlated with greater RNR severity (p < .001). In the multivariable logistic regression analysis, ASA occurrence was associated with smaller cross-sectional area, multiple stenotic sites, and severe-grade RNRs.

DISCUSSION

The presence of RNRs, particularly severe-grade RNRs, was identified as a significant risk factor for the development of ASA on electromyography. This finding may aid physicians in estimating the prognosis of patients with central spinal stenosis.

Small Joint Denervation of the Hand and Thumb Base: History, Anatomy, Technique, and Outcomes

Painful arthritis of the small joints of the hand is a common condition affecting older adults, with distal interphalangeal joint and thumb carpometacarpal joint being the two most common locations. Younger adults may also develop painful arthritis after trauma and with inflammatory arthropathy. Traditional surgical approaches address the structure of the joints with either arthrodesis or arthroplasty with or without an implant. In recent decades, denervation has been reported as an alternative treatment for painful small joints that are mobile and stable. Publications on denervation often report faster surgery and recovery times than traditional surgeries that manipulate the small joint bony structures. This article reviews the history, anatomy, surgical techniques, and outcomes of denervation of the small joints of the hand.

Muscle preservation in proximal nerve injuries: a current update

Optimal recovery of muscle function after proximal nerve injuries remains a complex and challenging problem. After a nerve injury, alterations in the affected muscles lead to atrophy, and later degeneration and replacement by fat-fibrous tissues. At present, several different strategies for the preservation of skeletal muscle have been reported, including various sets of physical exercises, muscle massage, physical methods (e.g. electrical stimulation, magnetic field and laser stimulation, low-intensity pulsed ultrasound), medicines (e.g. nutrients, natural and chemical agents, anti-inflammatory and antioxidants, hormones, enzymes and enzyme inhibitors), regenerative medicine (e.g. growth factors, stem cells and microbiota) and surgical procedures (e.g. supercharge end-to-side neurotization). The present review will focus on methods that aimed to minimize the damage to muscles after denervation based on our present knowledge.

Impact of Renal Denervation on Urinary Peptide-Based Biomarkers in Hypertension

BACKGROUND

Catheter-based renal denervation (RDN) reduces blood pressure in hypertension. Urinary peptides are associated with cardiovascular and renal disease and provide prognostic information. We aimed to investigate the effect of RDN on urinary peptide-based classifiers associated with chronic kidney and heart disease and to identify urinary peptides affected by RDN.

METHODS

This single-arm, single-center study included patients undergoing catheter-based RDN. Urine samples were collected before and 24 months after RDN and were analyzed using capillary electrophoresis coupled with mass spectrometry. Predefined urinary peptide-based classifiers for chronic kidney disease (CKD273), coronary artery disease (CAD238), and heart failure (HF1) were applied.

RESULTS

This study included 48 patients (33% female) with uncontrolled hypertension. At 24 months after RDN, systolic blood pressure (165±17 versus 148±20 mm Hg; P<0.0001), diastolic blood pressure (90±17 versus 81±13 mm Hg; P<0.0001), and mean arterial pressure (115±15 versus 103±13 mm Hg; P<0.0001) decreased significantly. A total of 103 urinary peptides from 37 different proteins, mostly collagens, altered following RDN. CAD238, a 238 coronary artery-specific polypeptide-based classifier, significantly improved following RDN (Cohen's d, -0.632; P=0.0001). The classification scores of HF1 (P=0.8295) and CKD273 (P=0.6293) did not change significantly.

CONCLUSIONS

RDN beneficially affected urinary peptides associated with coronary artery disease.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01888315.

Higher expression of denervation-responsive genes is negatively associated with muscle volume and performance traits in the study of muscle, mobility, and aging (SOMMA)

With aging skeletal muscle fibers undergo repeating cycles of denervation and reinnervation. In approximately the 8th decade of life reinnervation no longer keeps pace, resulting in the accumulation of persistently denervated muscle fibers that in turn cause an acceleration of muscle dysfunction. The significance of denervation in important clinical outcomes with aging is poorly studied. The Study of Muscle, Mobility, and Aging (SOMMA) is a large cohort study with the primary objective to assess how aging muscle biology impacts clinically important traits. Using transcriptomics data from vastus lateralis muscle biopsies in 575 participants we have selected 49 denervation-responsive genes to provide insights to the burden of denervation in SOMMA, to test the hypothesis that greater expression of denervation-responsive genes negatively associates with SOMMA participant traits that included time to walk 400 meters, fitness (VO2peak), maximal mitochondrial respiration, muscle mass and volume, and leg muscle strength and power. Consistent with our hypothesis, increased transcript levels of: a calciumdependent intercellular adhesion glycoprotein (CDH15), acetylcholine receptor subunits (CHRNA1, CHRND, CHRNE), a glycoprotein promoting reinnervation (NCAM1), a transcription factor regulating aspects of muscle organization (RUNX1), and a sodium channel (SCN5A) were each negatively associated with at least 3 of these traits. VO2peak and maximal respiration had the strongest negative associations with 15 and 19 denervation-responsive genes, respectively. In conclusion, the abundance of denervationresponsive gene transcripts is a significant determinant of muscle and mobility outcomes in aging humans, supporting the imperative to identify new treatment strategies to restore innervation in advanced age.

The cellular bases of mobility from the Study of Muscle, Mobility and Aging (SOMMA)

Findings from the Study of Muscle, Mobility and Aging (SOMMA) in this issue of Aging Cell show that several biological pathways in skeletal muscle cells play an important role in determining mobility in older adults. These are based on assays in skeletal muscle biopsies obtained from participants, aged 70 years and older in SOMMA tested for association with assessments related to mobility, including muscle mass, strength, power, cardiopulmonary fitness, and 400 m walking speed. The papers show that, using mass spectrometry, oxidative modifications of proteins essential to myocellular function are associated with poorer mobility. Using RNA-seq to quantify gene expression, lower levels of expression of antioxidant enzymes located in mitochondria, autophagy, patterns of expression of genes involved in autophagy, and higher levels of RNA transcripts that increase with denervation were associated with poorer performance on tests of mobility. These results extend previous research from the Baltimore Longitudinal Study of Aging and recent studies from SOMMA showing the importance of mitochondrial energetics in mobility. Together, these findings are painting a picture of how fundamental cellular processes influence the loss of mobility with aging. They may also be a window on aging in other cells, tissues, and systems. The data collected in SOMMA are publicly available and SOMMA welcomes collaborations with scientists who are interested in research about human aging.

Effectiveness of the Cooled Radiofrequency Ablation of Genicular Nerves in Patients with Chronic Knee Pain Due to Osteoarthritis: A Double-Blind, Randomized, Controlled Study

Background: Increasing evidence supporting the clinical effectiveness of cooled radiofrequency ablation (RFA) therapy for genicular nerves in patients with chronic knee osteoarthritis (OA) exists. However, no study has been conducted to eliminate the potential influence of a placebo effect associated with this procedure. Therefore, we evaluated the efficacy of cooled RFA compared with a sham procedure in patients with painful knees due to OA. Methods: In this double-blind, randomized, controlled study, participants were randomly assigned to receive cooled RFA of the knee (cooled RFA group, n = 20) or a sham procedure (sham group, n = 20). The primary outcome was the proportion of successful responders at the three-month follow-up. The secondary outcomes were successful responders at one and six months; pain intensity of the knee; functional status; medication; and satisfaction at one, three, and six months after the procedures. Results: For the primary outcome, the successful responder rate was significantly higher in the cooled RFA group (76.5%) than in the sham group (33.3%) (p = 0.018). For the secondary outcome, more successful responders were observed in the cooled RFA group than in the sham group at one and six months after the procedure (p = 0.041 and 0.007, respectively). The decreased knee pain intensity was maintained throughout the six-month follow-up period in the cooled RFA group. No differences were observed in functional status, medication change, or satisfaction in both groups. Conclusions: The cooled RFA of genicular nerves offers significant pain relief and surpasses the effects attributable to a placebo.

Outcomes of complete neurotomy and immediate repair of the musculocutaneous nerve for treatment of elbow spasticity

Neurotomy interrupts the stretch reflex and can be used for the treatment of spasticity. We hypothesized that neurotomy with nerve repair reduces spasticity while preserving motor function due to the preferential recovery of efferent over afferent fibres. This study reports the 1-year outcomes of neurotomy and immediate repair of the musculocutaneous nerve in the proximal arm for treatment of elbow flexor spasticity, comparing these to outcomes in the literature for neurectomy without nerve repair. A total of 10 adult patients with spasticity of the elbow flexors from stroke or traumatic brain injury who had undergone neurotomy and immediate repair of the musculocutaneous nerve were prospectively studied. The results suggest that this procedure effectively reduces elbow flexor spasticity, improves elbow resting position, active elbow extension and is useful for achieving patient goals with effects lasting at least 12 months.Level of evidence: IV (therapeutic).

The effects of resistance training on denervated myofibers, senescent cells, and associated protein markers in middle-aged adults

Denervated myofibers and senescent cells are hallmarks of skeletal muscle aging. However, sparse research has examined how resistance training affects these outcomes. We investigated the effects of unilateral leg extensor resistance training (2 days/week for 8 weeks) on denervated myofibers, senescent cells, and associated protein markers in apparently healthy middle-aged participants (MA, 55 ± 8 years old, 17 females, 9 males). We obtained dual-leg vastus lateralis (VL) muscle cross-sectional area (mCSA), VL biopsies, and strength assessments before and after training. Fiber cross-sectional area (fCSA), satellite cells (Pax7+), denervated myofibers (NCAM+), senescent cells (p16+ or p21+), proteins associated with denervation and senescence, and senescence-associated secretory phenotype (SASP) proteins were analyzed from biopsy specimens. Leg extensor peak torque increased after training (p < .001), while VL mCSA trended upward (interaction p = .082). No significant changes were observed for Type I/II fCSAs, NCAM+ myofibers, or senescent (p16+ or p21+) cells, albeit satellite cells increased after training (p = .037). While >90% satellite cells were not p16+ or p21+, most p16+ and p21+ cells were Pax7+ (>90% on average). Training altered 13 out of 46 proteins related to muscle-nerve communication (all upregulated, p < .05) and 10 out of 19 proteins related to cellular senescence (9 upregulated, p < .05). Only 1 out of 17 SASP protein increased with training (IGFBP-3, p = .031). In conclusion, resistance training upregulates proteins associated with muscle-nerve communication in MA participants but does not alter NCAM+ myofibers. Moreover, while training increased senescence-related proteins, this coincided with an increase in satellite cells but not alterations in senescent cell content or SASP proteins. These latter findings suggest shorter term resistance training is an unlikely inducer of cellular senescence in apparently healthy middle-aged participants. However, similar study designs are needed in older and diseased populations before definitive conclusions can be drawn.