Assessment of diagnostic criteria for multifocal motor neuropathy in patients included in the Italian database.

BACKGROUND AND PURPOSE: This study aimed to assess the diagnostic criteria, ancillary investigations and treatment response using real-life data in multifocal motor neuropathy (MMN) patients. METHODS: Clinical and laboratory data were collected from 110 patients enrolled in the Italian MMN database through a structured questionnaire. Twenty-six patients were excluded due to the unavailability of nerve conduction studies or the presence of clinical signs and symptoms and electrodiagnostic abnormalities inconsistent with the MMN diagnosis. Analyses were conducted on 73 patients with a confirmed MMN diagnosis and 11 patients who did not meet the diagnostic criteria. RESULTS: The European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) diagnostic criteria were variably applied. AUTHOR: When applying the American Association of Electrodiagnostic Medicine criteria, an additional 17% of patients fulfilled the criteria for probable/definite diagnosis whilst a further 9.5% missed the diagnosis. In 17% of the patients only compound muscle action potential amplitude, but not area, was measured and subsequently recorded in the database by the treating physician. Additional investigations, including anti-GM1 immunoglobulin M antibodies, cerebrospinal fluid analysis, nerve ultrasound and magnetic resonance imaging, supported the diagnosis in 46%-83% of the patients. Anti-GM1 immunoglobulin M antibodies and nerve ultrasound demonstrated the highest sensitivity. Additional tests were frequently performed outside the EFNS/PNS guideline recommendations. CONCLUSIONS: This study provides insights into the real-world diagnostic and management strategies for MMN, highlighting the challenges in applying diagnostic criteria.

Assessment of the Factors Influencing the Recording Performance of Circumneural Electrodes.

The quality of recorded peripheral nerve signals is decisive for their application in therapies. The electroneurogram can be recorded via implantable circumeural electrodes that are wrapped around the peripheral nerve. The shape and amplitude of the signal recorded by the electrode are influenced by the design and contact configuration of the electrode. In this paper, the impact of the number of contacts, contact size and electrical insulation to the outside is investigated to predict the single fiber action potential based on the measured impedance data.

Ultrasound assessment of medial crural cutaneous nerve and infrapatellar branch and of the saphenous nerve: establishing a safety zone for preventing nerve injury in knee surgery and injections.

PURPOSE: Our study aimed to illustrate the positional relationship of the two branches of the saphenous nerve: the infrapatellar branch of the saphenous nerve (IPBSN) and medial crural cutaneous nerve (MCCN), as well as the anatomical landmarks using high-resolution ultrasound (HRUS) to help prevent iatrogenic nerve injury. METHODS: We used HRUS to explore the positional relationships among the anatomical landmarks, IPBSN, and MCCN in 40 knees of 20 participants. The distances from these branches to key reference points were recorded. Using the ultrasound caliper mode, we measured the depth from the skin surface to the nerves at four distinct points. RESULTS: The average distances between IPBSN and medial border of patella (MBP) and IPBSN and medial border of patellar ligament (MBPL) were 47 ± 7 mm and 42 ± 9 mm, respectively. MCCN showed mean distances of 94 ± 9 mm and 96 ± 9 mm to MBP and MBPL, respectively. The mean distance from the upper edge of pes anserine to IPBSN at the patellar apex (PA) level was 24 ± 10 mm and to MCCN was 34 ± 9 mm. CONCLUSION: We used high-resolution ultrasound to evaluate IPBSN and MCCN and their positions relative to anatomical landmarks. The study results offer valuable insights into the course of these nerves, which can help establish a safety zone to prevent accidental nerve injuries during knee surgeries and injections.

Methods for automated delineation and assessment of EMG responses evoked by peripheral nerve stimulation in diagnostic and closed-loop therapeutic applications.

Objective.Surface electromyography measurements of the Hoffmann (H-) reflex are essential in a wide range of neuroscientific and clinical applications. One promising emerging therapeutic application is H-reflex operant conditioning, whereby a person is trained to modulate the H-reflex, with generalized beneficial effects on sensorimotor function in chronic neuromuscular disorders. Both traditional diagnostic and novel realtime therapeutic applications rely on accurate definitions of the H-reflex and M-wave temporal bounds, which currently depend on expert case-by-case judgment. The current study automates such judgments.Approach.Our novel wavelet-based algorithm automatically determines temporal extent and amplitude of the human soleus H-reflex and M-wave. In each of 20 participants, the algorithm was trained on data from a preliminary 3 or 4 min recruitment-curve measurement. Output was evaluated on parametric fits to subsequent sessions' recruitment curves (92 curves across all participants) and on the conditioning protocol's subsequent baseline trials (∼1200 per participant) performed nearHmax. Results were compared against the original temporal bounds estimated at the time, and against retrospective estimates made by an expert 6 years later.Main results.Automatic bounds agreed well with manual estimates: 95% lay within ±2.5 ms. The resulting H-reflex magnitude estimates showed excellent agreement (97.5% average across participants) between automatic and retrospective bounds regarding which trials would be considered successful for operant conditioning. Recruitment-curve parameters also agreed well between automatic and manual methods: 95% of the automatic estimates of the current required to elicitHmaxfell within±1.4%of the retrospective estimate; for the 'threshold' current that produced an M-wave 10% of maximum, this value was±3.5%.Significance.Such dependable automation of M-wave and H-reflex definition should make both established and emerging H-reflex protocols considerably less vulnerable to inter-personnel variability and human error, increasing translational potential.

Digital Nerve Injury: Assessment and Treatment.

Undertreated digital nerve injuries may result in sensory deficits and pain. Early recognition and treatment will optimize outcomes, and providers should maintain a high index of suspicion when assessing patients with open wounds. Acute, sharp lacerations may be amenable to direct repair while avulsion injuries or delayed repairs require adequate resection and bridging with nerve autograft, processed nerve allograft, or conduits. Conduits are most appropriate for gaps less than 15 mm, and processed nerve allografts have demonstrated reliable outcomes across longer gaps.

The incidence and management of peripheral nerve injury in England (2005-2020).

Peripheral nerve injury (PNI) is a significant health problem that confers lifelong impact on those injured. Current interventions are purely surgical; however, outcomes remain poor. There is a lack of high-quality epidemiological data that is needed to identify populations involved, current healthcare demands, and ensure resources are distributed to the greatest effect, to reduce the injury burden. METHODS: Anonymized hospital episode statistical (HES) data on admitted patient care was obtained from NHS Digital for all National Health Service (NHS) patients sustaining PNI of all body regions between 2005 and 2020. Total numbers of finished consultant episodes (FCEs) or FCEs/100,000 population were used to demonstrate changes in demographic variables, anatomical locations of injury, mechanisms of injury, speciality, and main operation. RESULTS: There was a mean national incidence of 11.2 (95% CI 10.9, 11.6) events per 100,000 population per year. Males were at least twice as likely (p < 0.0001) to sustain a PNI. Upper limb nerves at or distal to the wrist were most commonly injured. Knife injuries increased (p < 0.0001), whereas glass injuries decreased (p < 0.0001). Plastic surgeons increasingly managed PNI (p = 0.002) as opposed to orthopaedic surgeons (p = 0.006) or neurosurgeons (p = 0.001). There was an increase in neurosynthesis (p = 0.022) and graft procedures (p < 0.0001) during the study period. DISCUSSION: PNI is a significant national healthcare problem predominantly affecting distal, upper limb nerves of men of working age. Injury prevention strategies, improved targeted funding and rehabilitation pathways are needed to reduce the injury burden and improve patient care.

Second Harmonic Generation Microscopy as a Novel Intraoperative Assessment of Rat Median Nerve Injury.

PURPOSE: Nerves that are functionally injured but appear macroscopically intact pose the biggest clinical dilemma. Second Harmonic Generation (SHG) Microscopy may provide a real-time assessment of nerve damage, with the ultimate goal of allowing surgeons to accurately quantify the degree of nerve damage present. The aim of this study was to demonstrate the utility of SHG microscopy to detect nerve damage in vivo in an animal model. METHODS: Ten Sprague-Dawley rats were anesthetized and prepared for surgery. After surgical exposure and using a custom-made stretch applicator, the right median nerves were stretched by 20%, corresponding to a high strain injury, and held for 5 minutes. The left median nerve served as a sham control (SC), only being placed in the applicator for 5 minutes with no stretch. A nerve stimulator was used to assess the amount of stimulation required to induce a flicker and contraction of the paw. Nerves were then imaged using a multiphoton laser scanning microscope. RESULTS: Immediately after injury (day 0), SHG images of SC median nerves exhibited parallel collagen fibers with linear, organized alignment. In comparison with SC nerves, high strain nerves demonstrated artifacts indicative of nerve damage consisting of wavy, undulating fibers with crossing fibers and tears, as well as a decrease in the linear organization, which correlated with an increase in the mean stimulation required to induce a flicker and contraction of the paw. CONCLUSIONS: Second Harmonic Generation microscopy may provide the ability to detect an acute neural stretch injury in the rat median nerve. Epineurial collagen disorganization correlated with the stimulation required for nerve function. CLINICAL RELEVANCE: In the future, SHG may provide the ability to visualize nerve damage intraoperatively, allowing for better clinical decision-making. However, this is currently a research tool and requires further validation before translating to the clinical setting.

Value of ultrasound assessment for traumatic nerve injury of the upper limb.

AIM OF WORK: The type of traumatic peripheral nerve injury is a key factor for determining optimal treatment. Proper assessment of peripheral nerve injury facilitates appropriate treatment, significantly affects prognosis, and reduces disabilities. This study evaluated ultrasonography (US) to assess upper limb traumatic nerve injuries and compared the US with electrodiagnostic studies as the gold standard. MATERIALS AND METHODS: Participants were 69 adults (57 [83%] men, 12 [17%] women; mean age 36.3 ± 13.5 years) with a total of 96 peripheral nerve injuries (duration of 1 month-3 years). High-frequency US examinations and electro-physiologic studies confirmed upper limb peripheral nerve injury. RESULTS: Nerve discontinuation was diagnosed in 15 (15.6%) nerves; the cross-sectional area was increased in 33 (34.4%) nerves. Of 96 injuries, 54 (56.3%) were median, 24 (25%) were ulnar, and 18 (18.8%) were radial nerves. No statistically significant difference was found between US and electro-physiologic studies for nerve injury diagnosis (p = 0.054). CONCLUSION: No significant differences were found between US and electro-physiologic studies for diagnosis of nerve injuries; however, US was valuable to assess surrounding tissue and supplied muscles. The capabilities to detect nerve injury and associated distal muscular, vascular, and other regional structures position the US as a complementary diagnostic tool.

Quantification and Proximal-to-Distal Distribution Pattern of Tibial Nerve Lesions in Relapsing-Remitting Multiple Sclerosis : Assessment by MR Neurography.

PURPOSE: Recent studies suggest an involvement of the peripheral nervous system (PNS) in multiple sclerosis (MS). Here, we characterize the proximal-to-distal distribution pattern of peripheral nerve lesions in relapsing-remitting MS (RRMS) by quantitative magnetic resonance neurography (MRN). METHODS: A total of 35 patients with RRMS were prospectively included and underwent detailed neurologic and electrophysiologic examinations. Additionally, 30 age- and sex-matched healthy controls were recruited. 3T MRN with anatomical coverage from the proximal thigh down to the tibiotalar joint was conducted using dual-echo 2­dimensional relaxometry sequences with spectral fat saturation. Quantification of PNS involvement was performed by evaluating microstructural (proton spin density (ρ), T2-relaxation time (T2app)), and morphometric (cross-sectional area, CSA) MRN markers in every axial slice. RESULTS: In patients with RRMS, tibial nerve lesions at the thigh and the lower leg were characterized by a decrease in T2app and an increase in ρ compared to controls (T2app thigh: p < 0.0001, T2app lower leg: p = 0.0040; ρ thigh: p < 0.0001; ρ lower leg: p = 0.0098). An additional increase in nerve CSA was only detectable at the thigh, while the semi-quantitative marker T2w-signal was not altered in RRMS in both locations. A slight proximal-to-distal gradient was observed for T2app and T2-signal, but not for ρ. CONCLUSION: PNS involvement in RRMS is characterized by a decrease in T2app and an increase in ρ, occurring with proximal predominance at the thigh and the lower leg. Our results indicate microstructural alterations in the extracellular matrix of peripheral nerves in RRMS and may contribute to a better understanding of the pathophysiologic relevance of PNS involvement.

[New Technologies in Microsurgery: Potential, Indications and Economical Aspects - Report of the Consensus Workshop of the German-Speaking Society for Microsurgery of Peripheral Nerves and Vessels (DAM)]. / Neue Technologien in der Mikrochirurgie: Potential, Indikationen und ökonomische Aspekte ­ Konsensus-Bericht der Deutschsprachigen Arbeitsgemeinschaft für Mikrochirurgie der peripheren Nerven und Gefäße (DAM).

Recently, several new technologies to support microsurgeons have received European market approval. This article summarizes and discusses the impressions of an expert panel to classify the potential of new technologies in terms of benefits for the surgeon, specific indications and economic aspects during the 42nd Annual Meeting of the German-speaking Working Group for Microsurgery of Peripheral Nerves and Vessels (DAM) in Graz, Austria. In general, the expert panel addressed the principles and prerequisite for the successful establishment of new technologies and, in particular, novel optical and robotic systems. For this purpose, the current scientific literature was reviewed and initial clinical experience in the context of case series and retrospective studies was presented by the members of the expert panel. In the ensuing discussion, it was pointed out that it will first be necessary to identify patient subgroups in which the use of the new technologies is most likely to achieve a clinical benefit. Since clinical approval has already been granted for some systems, an approach can be developed for immediate clinical application from the simplest possible use to ever finer applications, i. e. from microsurgery to supermicrosurgery. Initially, funding for cost-intensive systems would presumably not be possible through revenue from standard care, but only through grants or subsidized clinical trials. In a final survey, the majority of meeting participants see the need for a price reduction of both visualization and surgical robotics technologies to enable widespread clinical establishment. Likewise, a majority of participants would prefer a combination of an exoscope or robotic microscope and a surgical robot for clinical use. The present consensus work addresses the development of a strategy for the effective establishment of new technologies, which should further increase the surgical quality of selected interventions.

Resident peripheral nerve surgery competence: An assessment of procedural exposure, self-reported competence and technical ability.

BACKGROUND: Identifying peripheral nerve surgery procedure (PNSP) competencies is crucial to ensure adequate resident training. We examine PNSP training at neurosurgical centers in the US and Canada to compare resident-reported competence, PNSP exposure, and resident technical abilities in performing 3 peripheral nerve coaptations (PNC). METHODS: Resident-reported PNSP competence and PNSP exposure data were collected using questionnaires from neurosurgical residents at North American neurosurgical training centers. Exposure and self-reported competency were correlated with technical skills. Technical PNC variables collected included: time-to-completion, nerve-handling from video-analysis, independent and blinded visual-analog-scale (VAS) PNC quality grading by 3 judges, and training level. RESULTS: A total of 40 neurosurgical residents participated in the study. Although self-reported competency scores correlated with procedural exposure (P < 0.01, rs = 0.88), a discrepancy was found between the degree of self-reported competency and amount of exposure. The discrepancy was greater in senior residents. A significant VAS difference was found between PNC types with the direct-suture and connector-assister groups scoring higher than connector-only (P = 0.02, P < 0.01, respectively). No difference was observed between training level and VAS grading, nor time-to completion (P = 0.33 and 0.25, respectively). No correlation was found between self-reported competency performing PNSPs and PNC VAS scores, nor nerve handling. CONCLUSIONS: Despite more exposure and a higher self-reported PNSP competency in senior residents, no difference was seen between senior/junior residents in PNC quality. A discrepancy in PNSP exposure and self-reported competency exists. This information will provide guidance for the direction of resident PNS training.

In vivo neurophysiological assessment of in silico predictions of neurotoxicity: Citronellal, 3,4-dichloro-1-butene, and benzyl bromoacetate.

Neurotoxicants may be widespread in the environment and can produce serious health impacts in the human population. Screening programs that use in vitro methods have generated data for thousands of chemicals. However, these methods often do not evaluate repeated or prolonged exposures, which are required for many neurotoxic outcomes. Additionally, the data produced by such screening methods may not include mechanisms which play critical biological roles necessary for in vivo neurotoxicity. The Hard and Soft Acids and Bases (HSAB) in silico model focuses on chemical structure and electrophilic properties which are important to the formation of protein adducts. A group of structurally diverse chemicals have been evaluated with an in silico screening approach incorporating HSAB parameters. However, the predictions from the expanded chemical space have not been evaluated using in vivo methods. Three chemicals predicted to be cumulative toxicants were selected for in vivo neurotoxicological testing. Adult male Long-Evans rats were treated orally with citronellal (CIT), 3,4-dichloro-1-butene (DCB), or benzyl bromoacetate (BBA) for 8 weeks. Behavioral observations were recorded weekly to assess motor function. Peripheral neurophysiological measurements were derived from nerve excitability (NE) tests which involved compound muscle action potentials (CMAPs) in the tail and foot, and mixed nerve action potentials (MNAPs) in the tail. Compound nerve action potentials (CNAPs) and nerve conduction velocity (NCV) in the tail were also quantified. Peripheral inputs into the central nervous system were examined using somatosensory evoked potentials recorded from the cortex (SEPCTX) and cerebellum (SEPCEREB). CIT or BBA did not result in significant alterations to peripheral nerve or somatosensory function. DCB reduced grip-strength and altered peripheral nerve function. The MNAPs required less current to reach 50% amplitude and had a lower calculated rheobase, suggesting increased excitability. Increased CNAP amplitudes and greater NCV were also observed. Novel changes were found in the SEPCTX with an abnormal peak forming in the early portion of the waveforms of treated rats, and decreased latencies and increased amplitudes were observed in SEPCEREB recordings. These data contribute to testing an expanded chemical space from an in silico HSAB model for predicting cumulative neurotoxicity and may assist with prioritizing chemicals to protect human health.

Local infiltration analgesia versus peripheral nerve block anaesthesia in total knee arthroplasty: a pharmaco-economic comparison.

BACKGROUND: A superior analgesic method in perioperative pain-management of patients receiving total knee arthroplasty is the subject of controversial debate. Although higher cost-efficiency is claimed for the local infiltration analgesia (LIA), there is a lack of data on its costs compared to peripheral nerve block anaesthesia (PNBA). The goal of this study was to investigate the differences in immediate perioperative costs between the LIA and PNBA in treatment of patients receiving total knee arthroplasty. METHODS: The comparison was conducted based on a randomized controlled clinical trial examining 40 patients with elective, primary total knee arthroplasty (TKA, 20 patients with LIA and 20 patients with PNBA). The analysis included surgical case costs, anaesthesiological case costs, material, costs of postoperative opioid requirements and catheter review visits for patients receiving PNBA. RESULTS: The overall mean costs for the LIA-group were 4328.72€ and 4368.12€ for the PNBA (p = 0.851). While there was no statistically significant difference in surgical case costs, the anaesthesiological costs were lower with the LIA procedure (1370.26€ vs. 1542.45€, p = 0.048). Material costs in the LIA group were 4.18€/patient and 94.64€/patient with the PNBA. Costs for postoperative opioid requirements showed no statistically significant difference between the two procedures. CONCLUSIONS: There is no relevant difference in immediate perioperative costs between LIA and PNBA. Shorter induction times lead to lower anaesthesiological case costs with the LIA. Overall economic aspects seem to play a less important role for determining an adequate procedure for perioperative pain management. TRIAL REGISTRATION: The study was approved by the ethics-review-board of Charité Hospital Berlin (Ethikausschuss 4, Charité - Universitätsmedizin Berlin, on 16th February 2017) and registered with data safety authorities. Study patients provided written informed consent to participate in the trial. Study registry: ClinicalTrials.gov, NCT03114306 .

Initial experience with label-free stimulated Raman scattering microscopy for intraoperative assessment of peripheral nerves.

BACKGROUND: During nerve repair, an intraoperative assessment of the quality of the nerve stump is critically important for achieving a good outcome. Frozen section analysis of osmium-hematoxylin stained sections has not been adopted at many centers, including ours. This has left us with bread-loafing the nerve and visually assessing for healthy fascicles. A technique that would allow for rapid, safe, quantitative intraoperative assessment of nerve quality, including myelin quantity, would be beneficial. Stimulated Raman Scattering (SRS) microscopy is a rapid, label-free technique that images lipids well that may be uniquely suited for this purpose. OBJECTIVE: To describe our initial experience and lessons learned using SRS microscopy for evaluation of peripheral nerve tissue. METHODS: We present 6 cases during which SRS microscopy was used to evaluate peripheral nerve tissue, including standard histology and SRS microscopy images, where applicable. RESULTS: Our current technique involves OCT embedding the nerve tissue and then cutting 70 µm sections on a standard cryostat. The SRS microscope slide is modified to change the buffer depth from 100 µm to 50 µm. We analyzed the gray scale composite images, merged from the CH2 (lipid) channel and CH3 (protein) channel. This technique reliably produced cross-sectional images and showed good capability for imaging myelinated axons within fascicles. CONCLUSIONS: We demonstrate here an innovative approach to quantifying myelin in peripheral nerve using Stimulated Raman Scattering microscopy. This should prove useful in the care and surgical treatment of patients with peripheral nerve injuries.

Role of sonography in assessment of upper extremity nerve pathologies: A literature review.

BACKGROUND AND PURPOSE: High-resolution ultrasound is a useful tool in the imaging of upper extremity nerves and depiction of morphology/structural abnormalities, with the benefits of cost-effectiveness, ease of access and capability of dynamic assessment. The focus of this review article will be sonographic assessment of pathologies of commonly imaged upper extremity nerves: radial, median and ulnar nerves. METHODS: A review of the recent literature on sonography of upper extremity nerves was performed, using databases within PubMed, Google Scholar and OVID as well as a textbook resource. RESULTS: Ultrasound can provide valuable information in the assessment of the upper extremity nerves. It can demonstrate pathologies such as entrapment neuropathies, nerve tumours and traumatic nerve injuries. The sonographic features of these conditions will be discussed in this review article. CONCLUSION: Ultrasound is a useful imaging modality to investigate upper extremity nerve pathologies when clinically indicated and can guide subsequent management/treatment.

Trends in Peripheral Nerve Surgery: Workforce, Reimbursement, and Procedural Rates.

BACKGROUND: Peripheral nerve surgery is one of the smallest neurosurgical subspecialties. It is hypothesized that the number of neurosurgeons performing these procedures has declined over the last decade due to many factors, including limited training opportunities and lower compensation relative to other subspecialties. METHODS: Data for physicians who performed peripheral nerve surgical procedures (PNSPs) were obtained from the Medicare Provider Utilization Database and used to calculate the total number of procedures performed by physicians of each specialty for each year. The Physician Fee Schedule Look-Up Tool was used to determine reimbursement rates for the top 5 PNSPs for neurosurgeons, which were then adjusted for inflation using the U.S. Bureau of Labor's Consumer Price Index Inflation Calculator. RESULTS: From 2012 to 2019, the top 3 contributing specialties were orthopedic surgery, urology, and hand surgery. Both the percentage of PNSPs performed by neurosurgeons and the number of neurosurgeons performing PNSPs decreased. Between 2000 and 2020, the average reimbursement for the commonly identified codes 64721, 64718, 64722, and 64718 decreased, whereas the reimbursement for 64555 (implantation of peripheral nerve neurostimulator electrodes) increased. CONCLUSIONS: Despite an overall increase in number of PNSPs, the percentage of PNSPs performed by neurosurgeons decreased from 2012 to 2019. There was overall workforce exit among neurosurgical peripheral nerve specialists over time. From 2000 to 2020, the average reimbursement for most PNSPs has decreased. Further investigation is needed to establish factors contributing to these trends and how they may be mitigated.

Techniques for the standard histological and ultrastructural assessment of nerve biopsies.

It is always a challenge to acquire a clear picture of the pathological processes and changes in any disease. For this purpose, it is advantageous to directly examine the affected organ. Nerve biopsy has been a method of choice for decades to classify peripheral neuropathies and to find clues to uncover their etiology. The histologic examination of the peripheral nerve provides information on axonal or myelin pathology as well as on the surrounding connective tissue and vascularization of the nerve. Minimal requirements of the workup include paraffin histology as well as resin semithin section histology. Cryostat sections, teased fiber preparations and electron microscopy are potentially useful in a subset of cases. Here we describe our standard procedures for the workup of the tissue sample and provide examples of diagnostically relevant findings.

Peripheral nerve block anesthesia/analgesia for patients undergoing primary hip and knee arthroplasty: recommendations from the International Consensus on Anesthesia-Related Outcomes after Surgery (ICAROS) group based on a systematic review and meta-analysis of current literature.

BACKGROUND: Evidence-based international expert consensus regarding the impact of peripheral nerve block (PNB) use in total hip/knee arthroplasty surgery. METHODS: A systematic review and meta-analysis: randomized controlled and observational studies investigating the impact of PNB utilization on major complications, including mortality, cardiac, pulmonary, gastrointestinal, renal, thromboembolic, neurologic, infectious, and bleeding complications.Medline, PubMed, Embase, and Cochrane Library including Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, were queried from 1946 to August 4, 2020.The Grading of Recommendations Assessment, Development, and Evaluation approach was used to assess evidence quality and for the development of recommendations. RESULTS: Analysis of 122 studies revealed that PNB use (compared with no use) was associated with lower ORs for (OR with 95% CIs) for numerous complications (total hip and knee arthroplasties (THA/TKA), respectively): cognitive dysfunction (OR 0.30, 95% CI 0.17 to 0.53/OR 0.52, 95% CI 0.34 to 0.80), respiratory failure (OR 0.36, 95% CI 0.17 to 0.74/OR 0.37, 95% CI 0.18 to 0.75), cardiac complications (OR 0.84, 95% CI 0.76 to 0.93/OR 0.83, 95% CI 0.79 to 0.86), surgical site infections (OR 0.55 95% CI 0.47 to 0.64/OR 0.86 95% CI 0.80 to 0.91), thromboembolism (OR 0.74, 95% CI 0.58 to 0.96/OR 0.90, 95% CI 0.84 to 0.96) and blood transfusion (OR 0.84, 95% CI 0.83 to 0.86/OR 0.91, 95% CI 0.90 to 0.92). CONCLUSIONS: Based on the current body of evidence, the consensus group recommends PNB use in THA/TKA for improved outcomes. RECOMMENDATION: PNB use is recommended for patients undergoing THA and TKA except when contraindications preclude their use. Furthermore, the alignment of provider skills and practice location resources needs to be ensured. Evidence level: moderate; recommendation: strong.

Quantitative assessment of intraneural vascular alterations in peripheral nerve trauma using high-resolution neurosonography: technical note.

High-resolution neurosonography (HRNS) has become a major imaging modality in assessment of peripheral nerve trauma in the recent years. However, the vascular changes of traumatic lesions have not been quantitatively assessed in HRNS. Here, we describe the vascular-ratio, a novel HRNS-based quantitative parameter for the assessment of intraneural vascular alterations in patients with nerve lesions. N = 9 patients suffering from peripheral nerve trauma were examined clinically, electrophysiologically and with HRNS (SonoSite Exporte, Fuji). Image analyses using Fiji included determination of the established fascicular ratio (FR), the cross-section ratio (CSR), and as an extension, the calculation of a vascular ratio (VR) of the healthy versus damaged nerve and a muscle perfusion ratio (MPR) in comparison to a healthy control group. The mean VR in the healthy part of the affected nerve (14.14%) differed significantly (p < 0.0001) from the damaged part (VR of 43.26%). This coincides with significant differences in the FR and CSR calculated for the damaged part versus the healthy part and the controls. In comparison, there was no difference between VRs determined for the healthy part of the affected nerve and the healthy controls (14.14% / 17.72%). However, the MPR of denervated muscles was significantly decreased compared to the non-affected contralateral controls. VR and MPR serve as additional tools in assessing peripheral nerve trauma. Image analysis and calculation are feasible. Combined with the more morphologic FR and CSR, the VR and MPR provide a more detailed insight into alterations accompanying nerve trauma.

Occipital Nerve Stimulation for Refractory Chronic Cluster Headache: A Cost-Effectiveness Study.

INTRODUCTION: Occipital nerve stimulation (ONS) is proposed to treat refractory chronic cluster headache (rCCH), but its cost-effectiveness has not been evaluated, limiting its diffusion and reimbursement. MATERIALS AND METHODS: We performed a before-and-after economic study, from data collected prospectively in a nation-wide registry. We compared the cost-effectiveness of ONS associated with conventional treatment (intervention and postintervention period) to conventional treatment alone (preintervention period) in the same patients. The analysis was conducted on 76 rCCH patients from the French healthcare perspective at three months, then one year by extrapolation. Because of the impact of the disease on patient activity, indirect cost, such as sick leave and disability leave, was assessed second. RESULTS: The average total cost for three months was €7602 higher for the ONS strategy compared to conventional strategy with a gain of 0.07 quality-adjusted life-years (QALY), the incremental cost-effectiveness ratio (ICER) was then €109,676/QALY gained. The average extrapolated total cost for one year was €1344 lower for the ONS strategy (p = 0.5444) with a gain of 0.28 QALY (p < 0.0001), the ICER was then €-4846/QALY gained. The scatter plot of the probabilistic bootstrapping had 80% of the replications in the bottom right-hand quadrant, indicating that the ONS strategy is dominant. The average indirect cost for three months was €377 lower for the ONS strategy (p = 0.1261). DISCUSSION: This ONS cost-effectiveness study highlighted the limitations of a short-time horizon in an economic study that may lead the healthcare authorities to reject an innovative strategy, which is actually cost-effective. One-year extrapolation was the proposed solution to obtain results on which healthcare authorities can base their decisions. CONCLUSION: Considering the burden of rCCH and the efficacy and safety of ONS, the demonstration that ONS is dominant should help its diffusion, validation, and reimbursement by health authorities in this severely disabled population.