Systematic review of nerves at risk at the wrist in common surgical approaches to the forearm: Anatomical variations and surgical implications

Three commonly used approaches to the forearm in orthopedic surgery are Henry's, Thompson's, and the ulnar approach, each of which has the potential to cause injury to nerves around the wrist. Preserving these nerves is important to prevent complications such as neuroma formation and motor and sensory changes to the hand. We conducted a review of the literature to assess the nerves at risk and whether 'safe zones' exist to avoid these nerves. An independent reviewer conducted searches in Embase and MEDLINE of the literature from 2010 to 2020. A total of 68 papers were identified, with 18 articles being included in the review. Multiple nerves were identified as being at risk for each of the approaches described. In the anterior approach, the palmar cutaneous branch of the median nerve (PCBMN) is most at risk of injury. An incision immediately radial to the flexor carpi radialis (FCR) or directly over the FCR is most likely to avoid injury to both superficial branch of the radial nerve (SBRN) and PCBMN. With Thompson's approach, the safest zone for an incision is directly over or slightly radial to Lister's tubercle to avoid injury to SBRN and lateral cutaneous nerve of the forearm. For the ulnar approach, a safe zone was shown to be on the ulnar side of the wrist around the ulnar styloid (US) when the forearm was in supination or a neutral position to avoid injury to the dorsal branch of the ulna nerve (DBUN). Care must be taken around the US due to the density of nerves and the proximity of the last motor branch of the posterior interosseous nerve to the ulnar head. This review highlighted the proximity of nerves to the three most common surgical incisions used to access the forearm. In addition, anatomical variations may exist, and each of the nerves identified as being at risk has multiple branches. Both factors increase the potential of intraoperative damage if the anatomy is not properly understood. The surgeon must adhere carefully to the established approaches to the wrist and distal forearm to minimize damage to nerves and optimize surgical outcomes for the patient.

Nerve Visualization using Phenoxazine-Based Near-Infrared Fluorophores to Guide Prostatectomy

Fluorescence-guided surgery (FGS) is poised to revolutionize surgical medicine through near-infrared (NIR) fluorophores for tissue- and disease-specific contrast. Clinical open and laparoscopic FGS vision systems operate nearly exclusively at NIR wavelengths. However, tissue-specific NIR contrast agents compatible with clinically available imaging systems are lacking, leaving nerve tissue identification during prostatectomy a persistent challenge. Here, it is shown that combining drug-like molecular design concepts and fluorophore chemistry enabled the production of a library of NIR phenoxazine-based fluorophores for intraoperative nerve-specific imaging. The lead candidate readily delineated prostatic nerves in the canine and iliac plexus in the swine using the clinical da Vinci Surgical System that has been popularized for minimally invasive prostatectomy procedures. These results demonstrate the feasibility of molecular engineering of NIR nerve-binding fluorophores for ready integration into the existing surgical workflow, paving the path for clinical translation to reduce morbidity from nerve injury for prostate cancer patients.

Periampullary cancer and neurological interactions: current understanding and future research directions

Periampullary cancer is a malignant tumor occurring around the ampullary region of the liver and pancreas, encompassing a variety of tissue types and sharing numerous biological characteristics, including interactions with the nervous system. The nervous system plays a crucial role in regulating organ development, maintaining physiological equilibrium, and ensuring life process plasticity, a role that is equally pivotal in oncology. Investigations into nerve-tumor interactions have unveiled their key part in controlling cancer progression, inhibiting anti-tumor immune responses, facilitating invasion and metastasis, and triggering neuropathic pain. Despite many mechanisms by which nerve fibers contribute to cancer advancement still being incompletely understood, the growing emphasis on the significance of nerves within the tumor microenvironment in recent years has set the stage for the development of groundbreaking therapies. This includes combining current neuroactive medications with established therapeutic protocols. This review centers on the mechanisms of Periampullary cancer's interactions with nerves, the influence of various types of nerve innervation on cancer evolution, and outlines the horizons for ongoing and forthcoming research.

On the Physiology of the Sensory-Collapse Test

The sensory-collapse test (formerly the scratch-collapse test) is a physical examination finding describing a momentary inhibition of external shoulder rotation following light stimulation of an injured nerve in the ipsilateral limb. Similar to other physical examination tests designed to interrogate nerve compression, such as the Phalen or Tinel tests, its test characteristics demonstrate variation. There remains speculation about the test's existence and anatomic basis. The literature of mammalian reflex physiology was reviewed with an emphasis on the sensory pathways from the upper extremity, the extrapyramidal system, and newly discovered pathways and concepts of nociception. A clear reflex pathway is described connecting the stimulus within an injured nerve through the afferent pathways in the fasciculus cuneatus in the spinal cord directly to the lateral reticulospinal tract, resulting in the inhibition of extensor muscles in the proximal limb (eg, shoulder) and activation of the limb flexors by acting upon alpha and gamma motor neurons. The sensory-collapse test represents a reflex pathway that teleologically provides a mechanism to protect an injured nerve by withdrawal toward the trunk and away from the noxious environment.

Comprehensive mapping of sensory and sympathetic innervation of the developing kidney

The kidney functions as a finely tuned sensor to balance body fluid composition and filter out waste through complex coordinated mechanisms. This versatility requires tight neural control, with innervating efferent nerves playing a crucial role in regulating blood flow, glomerular filtration rate, water and sodium reabsorption, and renin release. In turn sensory afferents provide feedback to the central nervous system for the modulation of cardiovascular function. However, the cells targeted by sensory afferents and the physiological sensing mechanisms remain poorly characterized. Moreover, how the kidney is innervated during development to establish these functions remains elusive. Here, we utilized a combination of light-sheet and confocal microscopy to generate anatomical maps of kidney sensory and sympathetic nerves throughout development and resolve the establishment of functional crosstalk. Our analyses revealed that kidney innervation initiates at embryonic day (E)13.5 as the nerves associate with vascular smooth muscle cells and follow arterial differentiation. By E17.5 axonal projections associate with kidney structures such as glomeruli and tubules and the network continues to expand postnatally. These nerves are synapsin I-positive, highlighting ongoing axonogenesis and the potential for functional crosstalk. We show that sensory and sympathetic nerves innervate the kidney concomitantly and classify the sensory fibers as calcitonin gene related peptide (CGRP)+, substance P+, TRPV1+, and PIEZO2+, establishing the presence of PIEZO2 mechanosensory fibers in the kidney. Using retrograde tracing, we identified the primary dorsal root ganglia, T10-L2, from which PIEZO2+ sensory afferents project to the kidney. Taken together our findings elucidate the temporality of kidney innervation and resolve the identity of kidney sympathetic and sensory nerves.

Comparison of Erector Spinae Plane Block and Pectointercostal Facial Plane Block for Enhanced Recovery After Sternotomy in Adult Cardiac Surgery

OBJECTIVES

This study aimed to investigate and compare the effects of the pectointercostal fascial plane block (PIFPB) and the erector spinae plane block (ESPB) on enhancing the recovery of patients who undergo cardiac surgery.

DESIGN

A randomized, controlled, double-blinded study.

SETTING

The operating rooms and intensive care units of university hospitals.

PARTICIPANTS

One hundred patients who were American Society of Anesthesiologists class II to III aged 18-to-70 years scheduled for elective cardiac surgery.

INTERVENTIONS

Patients were randomly assigned to undergo either ultrasound-guided bilateral PIFPB or ESPB.

MEASUREMENTS AND MAIN RESULTS

Patients shared comparable baseline characteristics. Time to extubation, the primary outcome, did not demonstrate a statistically significant difference between the groups, with median (95% confidence interval) values of 115 (90-120) minutes and 110 (100-120) minutes, respectively (p = 0.875). The ESPB group had a statistically significant reduced pain score postoperatively. The median (IQR) values of postoperative fentanyl consumption were statistically significantly lower in the ESPB group than in the PIFPB group (p < 0.001): 4 (4-5) versus 9 (9-11) µg/kg, respectively. In the ESPB group, the first analgesia request was given 4 hours later than in the PIFPB group (p < 0.001). Additionally, 12 (24%) patients in the PIFPB group reported nonsternal wound chest pain, compared with none in the ESPB group. The median intensive care unit length of stay for both groups was 3 days (p = 0.428).

CONCLUSIONS

Erector spinae plane block and PIFPB were found to equally affect recovery after cardiac surgery, with comparable extubation times and intensive care unit length of stay.

Changes in Cross-sectional Area of the Median Nerve and Boston Carpal Tunnel Questionnaire Scores After Carpal Tunnel Release

BACKGROUND

We hypothesized that postoperative Boston Carpal Tunnel Questionnaire (BCTQ) scores and ultrasound (US) measurements of the median nerve cross-sectional area (CSA) at the distal wrist crease are significantly decreased at 2-week, 6-week, and ≥ 6 months follow-up appointments, compared with baseline values.

METHODS

This study was a retrospective chart review of patients who presented to a single hand clinic with evidence of carpal tunnel syndrome over a 6-year period (2014-2020). Patients received baseline US measurements of the median nerve CSA as well as completion of the BCTQ, and for the patients who underwent carpal tunnel release (CTR), postoperative US measurements and questionnaire scores were obtained at 2 weeks, 6 weeks, or ≥ 6 months postoperatively.

RESULTS

This study included 224 separate wrists. Median Nerve CSA measurements were 13.2 ± 4.5 mm2 at baseline, 11.9 ± 3.6 mm2 at 2 weeks postoperatively, 11.6 ± 4.5 mm2 at 6 weeks postoperatively, and 11.7 ± 4.3 mm2 at 6 months or more (P = .002). The BCTQ Symptom Severity Scale scores were 3.14 ± 0.76 at baseline, 1.76 ± 0.63 at 2 weeks, 1.68 ± 0.70 at 6 weeks, and 1.41 ± 0.64 at 6 months or longer (P < .001). The BCTQ Functional Status Scale scores were 2.56 ± 0.89 at baseline, 2.03 ± .1.0 at 2 weeks, 1.65 ± 0.77 at 6 weeks, and 1.36 ± 0.61 at 6 months or longer (P < .001).

CONCLUSIONS

These findings demonstrated a sustained decrease in median nerve CSA and patient-reported outcomes following CTR at 2 weeks, 6 weeks, and between 6 and 12 months.

Demographics of Common Compressive Neuropathies in the Upper Extremity

BACKGROUND

The purpose of this study was to compare the demographic differences of the most common peripheral nerve compressions in the upper extremity-carpal tunnel syndrome (CTS), ulnar nerve compression (UNC) at the elbow, combined CTS and UNC, radial tunnel syndrome (RTS), and posterior interosseous nerve syndrome (PINS)-as a means to better understand the etiologies of each.

METHODS

A retrospective chart review was performed of all patients over the age of 18 years seen at our institution in the 2018 calendar year. International Classification of Diseases, Tenth Revision codes were used to identify patients with diagnoses of upper extremity peripheral nerve compressions. Demographic details and relevant comorbidities were recorded for each patient and compared with controls, who were seen the same calendar year with no neuropathies. χ2 analyses, independent-samples t tests, and multivariate logistic regressions were performed (P < .05).

RESULTS

A total of 7448 patients were identified. Those with CTS were mainly women, former smokers, and diabetic (all P < .001) and with a greater average body mass index (BMI) (P = .006) than controls. Patients with UNC were more often men and younger when compared with controls (both P < .001). A history of smoking, diabetes, and average BMI were similar between patients with UNC and controls (all P > .05). Those patients with combined CTS/UNC were mainly men, former smokers, and diabetic (all P < .001) when compared with controls. Patients with RTS/PINS were also mostly men (P = .007), diabetic (P = .042), and were more often current smokers (P < .001).

CONCLUSIONS

The demographics of patients with various compressive neuropathies were not homogeneous, suggesting different etiologies.

Conduit/Wrap Repairs to Digital Nerves Provide Residual Strength After Peak Loading

BACKGROUND

Many techniques are used for digital nerve repair, most commonly coaptation by sutures. Nerve repairs must be strong while offering an environment for nerve regeneration. Sutures can damage the nerve and thereby limit growth and regeneration. Sutures can rip and cause sudden catastrophic failure. Fibrin glue and conduit-wraps allow a good environment for growth, but neither provides much strength. A benefit to conduit repair would arise if the repair maintained integrity after the peak load so that the path for regrowth stayed in place. The goal for this study was to determine whether conduit with glue provides continued strength after a maximum load is reached.

METHODS

Digital cadaveric nerves were harvested and repaired with 2 epineurial sutures, conduit, and fibrin glue in all combinations. Tests to failure were performed, gap displacement between nerve ends recorded, and the postpeak load energy to dissociation of the nerve and conduit was calculated.

RESULTS

Conduit with glue and 2 sutures at the end had the greatest energy and displacement after the peak load but was not significantly different than conduit with glue and 1 suture. Conduit with glue alone obtained statistically the same displacement as conduit with glue and 2 sutures. Conduit, with or without glue, and 2 sutures was statistically the same as suture only repair for peak load.

CONCLUSION

Conduit/wrap maintains a load capacity and a path for nerve regeneration after the peak. Suture at the ends of conduit, not at the coaptation site, reduces damage at the point of injury.

Posterior Interosseous Nerve Compression in the Forearm, AKA Radial Tunnel Syndrome: A Clinical Diagnosis

BACKGROUND

Posterior interosseous nerve (PIN) compression in the forearm without motor paralysis is a challenging clinical diagnosis. This retrospective study evaluated the clinical assessment, diagnostic studies, and outcomes following surgical decompression of the PIN in the forearm.

METHODS

This study reviewed 182 patients' medical charts following PIN decompression between 2000 and 2020 by a single surgeon. After exclusion of combined nerve entrapments, polyneuropathy, motor palsy, or lateral epicondylitis, the study included 14 patients. Data collected included: clinical presentation and pain drawings, provocative testing, functional outcomes, and Disabilities of the Arm, Shoulder, and Hand (DASH) scores.

RESULTS

There were 15 PIN decompressions (14 patients, mean follow-up = 11.9 months). Clinical presentation included pain (n = 14) (proximal dorsal forearm, n = 14; distal forearm over radial sensory nerve, n = 3) and positive clinical tests (sensory collapse test over the radial tunnel, n = 8; pain with forearm pronation and compression over the radial tunnel, n = 10; Tinel sign, n = 5). Postoperatively, there were significant improvements in Visual Analog Scale pain scores (6.7 to 3.3, P = .0006), quality-of-life scores (74.7 to 32.7, P = .0001), and DASH scores (46.3 to 33.6, P = .02).

CONCLUSIONS

The PIN compression in the forearm without motor paralysis is a clinical diagnosis supported by pain drawings, pain quality, and provocative tests. Patients with persistent, therapy-resistant dorsal forearm pain should be evaluated for PIN compression. Surgical decompression provides statistically significant quantifiable improvement in pain and quality of life.

Management of Bilateral Vocal Fold Paralysis: A Systematic Review

OBJECTIVE

To review the current literature about epidemiology, etiologies and surgical management of bilateral vocal fold paralysis (BVFP).

DATA SOURCES

PubMED, Scopus, and Cochrane Library.

REVIEW METHODS

A systematic review of the literature on epidemiology, etiologies, and management of adult patients with BVFP was conducted through preferred reporting items for systematic reviews and meta-analyses statements by 2 investigators.

RESULTS

Of the 360 identified papers, 245 were screened, and of these 55 were considered for review. The majority (76.6%) of BVFP cases are iatrogenic. BVFP requires immediate tracheotomy in 36.2% of cases. Laterofixation of the vocal fold was described in 9 studies and is a cost-effective alternative procedure to tracheotomy while awaiting potential recovery. Unilateral and bilateral posterior transverse cordotomy outcomes were reported in 9 and 7 studies, respectively. Both approaches are associated with a 95.1% decannulation rate, adequate airway volume, but voice quality worsening. Unilateral/bilateral partial arytenoidectomy data were described in 4 studies, which reported lower decannulation rate (83%) and better voice quality outcome than cordotomy. Revision rates and complications vary across studies, with complications mainly involving edema, granuloma, fibrosis, and scarring. Selective posterior cricoarytenoid reinnervation is being performed by more surgeons and should be a promising addition to the BVFP surgical armamentarium.

CONCLUSION

Depending on techniques, the management of BVFP may be associated with several degrees of airway improvements while worsened or unchanged voice quality. The heterogeneity between studies, the lack of large-cohort controlled randomized studies and the confusion with posterior glottic stenosis limit the draw of clear conclusion about the superiority of some techniques over others.

A Readability Study of Carpal Tunnel Release in 2023

BACKGROUND

The National Institutes of Health (NIH) and the American Medical Association (AMA) recommend a sixth-grade reading level for patient-directed content. This study aims to quantitatively evaluate the readability of online information sources related to carpal tunnel surgery using established readability indices.

METHODS

Web searches for "carpal tunnel release" and "carpal tunnel decompression surgery" queries were performed using Google, and the first 20 websites were identified per query. WebFX online software tools were utilized to determine readability. Indices included Flesch Kincaid Reading Ease, Flesch Kincaid Grade Level, Coleman Liau Index, Automated Readability Index, Gunning Fog Score, and the Simple Measure of Gobbledygook Index. Health-specific clickthrough rate (CTR) data were used in order to select the first 20 search engine results page from each query.

RESULTS

"Carpal tunnel release" had a mean readability of 8.46, and "carpal tunnel decompression surgery" had a mean readability of 8.70. The range of mean readability scores among the indices used for both search queries was 6.17 to 14.0. The total mean readability for carpal tunnel surgery information was found to be 8.58. This corresponds to approximately a ninth-grade reading level in the United States.

CONCLUSION

The average readability of carpal tunnel surgery online content is three grade levels above the recommended sixth-grade level for patient-directed materials. This discrepancy indicates that existing online materials related to carpal tunnel surgery are more difficult to understand than the standards set by NIH and AMA.

Social Media Posts About Carpal Tunnel Release: A Cross-Sectional Analysis of Patient and Surgeon Perspectives

BACKGROUND

Social media provides an increasingly popular, unfiltered source of perspectives on healthcare. The objective of this study is to characterize the landscape of social media posts regarding carpal tunnel release (CTR).

METHODS

Content was queried from Instagram between February 2, 2019 to August 12, 2021 using the hashtags #carpaltunnelrelease and #carpaltunnelsurgery. The 1500 most-liked posts were analyzed. Poster demographics including age, gender, region, and symptom qualities and post characteristics including type, number, timing relative to surgery, tone, and satisfaction were collected. Categorical variables were compared utilizing chi-squared test. Univariate and multivariate regression were performed.

RESULTS

The most popular post types included single photo (55.2%), multiple photos (18.8%), or single video (18.2%). Of all, 70.6% posts had fewer than 50 "likes." Patients accounted for 51.8% of posts, followed by surgeons (13.3%), other health care providers (11.7%), and physical therapists (8.8%). Women (66.7%) outnumbered men (33.3%). Fifty-five percent of posts were domestic. Posts mostly depicted postoperative care (85.6%). The most frequently mentioned symptoms were pain, burning, numbness, and tingling. Of all posts, 45.1% had a positive tone, 49.1% neutral, and 5.7% negative. Univariate analysis revealed that posters who were patients, underwent open CTR, and were female were more likely to post negative sentiments.

CONCLUSIONS

Most posts regarding CTR are from patients, are postoperative, and are positive or neutral. Although rare, negative posts were more likely to originate from posters who are patients, female, or underwent open CTR. With this information, surgeons will be better prepared to address patient concerns, set patient expectations, and enter the social media themselves.

Risk Factors for Rescue Opioid Prescription After Cubital Tunnel Surgery

BACKGROUND

Concerns regarding the ongoing opioid epidemic have led to heightened scrutiny of postoperative opioid prescribing patterns for common orthopedic surgical procedures. This study investigated patient- and procedure-specific risk factors for additional postoperative opioid rescue prescriptions following ambulatory cubital tunnel surgery.

METHODS

A retrospective review was performed of patients who underwent cubital tunnel surgery at 2 academic medical centers between June 1, 2015 and March 1, 2020. Patient demographics, comorbidities, prior opioid history, and surgical variables were recorded. The primary outcome was postoperative rescue opioid prescription. Univariate and bivariate statistical analyses were performed.

RESULTS

Two hundred seventy-four patients were included, of whom 171 (62%) underwent in situ ulnar nerve decompression and 103 (38%) underwent ulnar nerve decompression with anterior transposition. The median postoperative opioid prescription amount was 90 morphine equivalent units (MEU) for the total cohort, 77.5 MEU for in situ ulnar nerve decompression, and 112.5 MEU for ulnar nerve decompression with transposition. Twenty-two patients (8%) required additional rescue opioid prescriptions postoperatively. Female sex, fibromyalgia, chronic opioid use, chronic pain diagnosis, and recent opioid were associated with the need for additional postoperative rescue opioid prescriptions.

CONCLUSIONS

While most patients do not require additional rescue opioid prescriptions after cubital tunnel surgery, chronic pain patients and patients with pain sensitivity syndromes are at risk for requiring additional rescue opioid prescriptions. For these high-risk patients, preoperative collaboration of a multidisciplinary team may be beneficial for developing a perioperative pain management plan that is both safe and effective.

Comparison of distortion correction preprocessing pipelines for DTI in the upper limb

PURPOSE

DTI characterizes tissue microstructure and provides proxy measures of nerve health. Echo-planar imaging is a popular method of acquiring DTI but is susceptible to various artifacts (e.g., susceptibility, motion, and eddy currents), which may be ameliorated via preprocessing. There are many pipelines available but limited data comparing their performance, which provides the rationale for this study.

METHODS

DTI was acquired from the upper limb of heathy volunteers at 3T in blip-up and blip-down directions. Data were independently corrected using (i) FSL's TOPUP & eddy, (ii) FSL's TOPUP, (iii) DSI Studio, and (iv) TORTOISE. DTI metrics were extracted from the median, radial, and ulnar nerves and compared (between pipelines) using mixed-effects linear regression. The geometric similarity of corrected b = 0 images and the slice matched T1-weighted (T1w) images were computed using the Sörenson-Dice coefficient.

RESULTS

Without preprocessing, the similarity coefficient of the blip-up and blip-down datasets to the T1w was 0·80 and 0·79, respectively. Preprocessing improved the geometric similarity by 1% with no difference between pipelines. Compared to TOPUP & eddy, DSI Studio and TORTOISE generated 2% and 6% lower estimates of fractional anisotropy, and 6% and 13% higher estimates of radial diffusivity, respectively. Estimates of anisotropy from TOPUP & eddy versus TOPUP were not different but TOPUP reduced radial diffusivity by 3%. The agreement of DTI metrics between pipelines was poor.

CONCLUSIONS

Preprocessing DTI from the upper limb improves geometric similarity but the choice of the pipeline introduces clinically important variability in diffusion parameter estimates from peripheral nerves.

Subjective Voice Outcomes in Surgeon Versus Technician-Monitored Recurrent Laryngeal Nerves in Thyroidectomy

OBJECTIVES

To compare subjective voice outcomes and postoperative laryngoscopic examination findings of patients with subjective voice complaints between surgeon-monitored and certified technician-monitored thyroidectomies.

METHODS

Patients who underwent hemithyroidectomy, total thyroidectomy, and completion thyroidectomy using a nerve monitoring system between November 2015 and June 2018 were included in the study. Retrospective chart review was carried out to assess how often patients reported voice changes and to record postoperative flexible laryngoscopic findings of patients when that examination was performed. Data were analyzed using the χ2 test to identify significant differences in outcomes for the 2 groups.

RESULTS

A total of 293 procedures was performed among 3 surgeons. Surgeons monitored the nerves in 147 cases and a certified technician monitored the nerves in 146 cases. Subjective voice changes were identified in 11 (7.48%) cases in the surgeon-monitored group and in 20 (13.70%) cases in the technician-monitored group (P = .084). Among the patients who expressed subjective voice changes, 7 patients were identified with vocal cord hypomobility or immobility in the surgeon-monitored group and 13 patients had an abnormal examination in the technician-monitored group (P = .234).

CONCLUSIONS

Subjective voice changes or proven vocal cord mobility problems were not different between surgeon-monitored patients and technician-monitored patients in thyroidectomies.

MRI order appropriateness for chronic neck pain: Comparison of ordering practices and treatment outcomes for primary care physicians and specialists

Chronic neck pain is a common reason for doctor visits in the United States. This diagnosis can be evaluated through patient history, physical examination, and judicious use of radiographs. However, possible inappropriate magnetic resonance imaging (MRI) ordering persists. We hypothesized that no difference in ordering practices, ordering appropriateness, and subsequent intervention would be appreciated regarding physician specialty, location, patient characteristics, and history and physical exam findings. A multisite retrospective review of cervical spine MRI between 2014 and 2018 was performed. A total of 332 patients were included. Statistical analysis was used to assess MRI order appropriateness, detail of history and physical exam findings, and intervention decision-making among different specialties. If significant differences were found, multiple linear regression was performed to evaluate the association of MRI order appropriateness regarding physician specialty, location, patient characteristics and history, and physical exam findings. The significance level for all tests was set at <0.05 Orthopedic surgeons ordered MRIs most appropriately with an average American College of Radiology (ACR) score of 8.4 (p < 0.005). Orthopedic surgeons had more comprehensive physical exams as compared to the remaining specialties. The decision for intervention did not vary by physician specialty or ACR score, except for patients of pain medicine physicians who received pain management (p = 0.000). Orthopedic surgeons utilize MRI most appropriately and have more comprehensive physical exams. These findings suggest a need for increased physician education on what indicates an appropriate MRI order to improve the use of resources and further protect patient risk-benefit profiles. Further research elucidating factors to minimize negative findings in "appropriate" MRIs is indicated. Clinical significance: More detailed physical exams may lead to more appropriately ordered MRIs, subsequently resulting in surgery or procedures being performed when appropriately indicated. This suggests the need for increased physician education on when MRI ordering is appropriate for chronic neck pain to improve the use of resources and further protect patient risk-benefit profiles.

Involvement of the autonomic nervous system in colonic contractions in conscious Suncus murinus

BACKGROUND

Colonic motility is regulated by various factors along the gut-brain axis; however, detailed mechanisms are unknown. This study aimed to examine the involvement of the autonomic nervous system in colonic motility. Suncus murinus (suncus) is a small laboratory mammal suitable for gastrointestinal motility studies.

METHODS

Colonic motility and concomitant feeding and defecation behaviors in vagotomized and reserpine-administered suncus were recorded simultaneously for 24 h. Furthermore, we performed immunohistochemistry on tyrosine hydroxylase (TH) and in situ hybridization on corticotropin-releasing hormone (CRH) in suncus brain. Additionally, we examined c-Fos expression in the brain using immunohistochemistry in conscious suncus with colorectal distension.

KEY RESULTS

In vagotomized suncus, clustered giant migrating contractions (GMCs), consisting of strong contractions occurring in a short time, were observed, and the percentage of GMCs without defecation increased. The frequency of GMCs in the reserpine-administered suncus increased during a light period (ZT0-4, 4-8) and decreased during a dark period (ZT16-20, 20-24) compared to a vehicle group. Additionally, the percentage of GMCs without defecation in the reserpine-administered suncus increased. Suncus TH-immunopositive neurons were found in the locus coeruleus (LC), as shown in rodents. In contrast, CRH mRNA-expressing cells were not observed in a region assumed to be the Barrington's nucleus (Bar). Furthermore, colorectal distension in conscious suncus induced c-Fos expression in LC TH neurons.

CONCLUSIONS & INFERENCES

Our results suggest that the vagus and sympathetic nerves are not required for induction of GMCs in vivo. However, they are likely to exert a modulatory role in control of GMC frequency in Suncus murinus.

Recent Achievements in the Development of Biomaterials Improved with Platelet Concentrates for Soft and Hard Tissue Engineering Applications

Platelet concentrates such as platelet-rich plasma, platelet-rich fibrin or concentrated growth factors are cost-effective autologous preparations containing various growth factors, including platelet-derived growth factor, transforming growth factor β, insulin-like growth factor 1 and vascular endothelial growth factor. For this reason, they are often used in regenerative medicine to treat wounds, nerve damage as well as cartilage and bone defects. Unfortunately, after administration, these preparations release growth factors very quickly, which lose their activity rapidly. As a consequence, this results in the need to repeat the therapy, which is associated with additional pain and discomfort for the patient. Recent research shows that combining platelet concentrates with biomaterials overcomes this problem because growth factors are released in a more sustainable manner. Moreover, this concept fits into the latest trends in tissue engineering, which include biomaterials, bioactive factors and cells. Therefore, this review presents the latest literature reports on the properties of biomaterials enriched with platelet concentrates for applications in skin, nerve, cartilage and bone tissue engineering.

A Novel Catalytically Inactive Construct of Botulinum Neurotoxin A (BoNT/A) Directly Inhibits Visceral Sensory Signalling

Botulinum neurotoxin A (BoNT/A) is a potent neurotoxin that silences cholinergic neurotransmission through the cleavage of the synaptic protein SNAP-25. Previous studies have shown that, in addition to its paralytic effects, BoNT/A can inhibit sensory nerve activity. The aim of this study was to identify how BoNT/A inhibits afferent signalling from the bladder. To investigate the role of SNAP-25 cleavage in the previously reported BoNT/A-dependent inhibition of sensory signalling, we developed a recombinant form of BoNT/A with an inactive light chain, rBoNT/A (0), unable to paralyse muscle. We also developed recombinant light chain (LC)-domain-only proteins to better understand the entry mechanisms, as the heavy chain (HC) of the protein is responsible for the internalisation of the light chain. We found that, despite a lack of catalytic activity, rBoNT/A (0) potently inhibited the afferent responses to bladder distension to a greater degree than catalytically active rBoNT/A. This was also clear from the testing of the LC-only proteins, as the inactive rLC/A (0) protein inhibited afferent responses significantly more than the active rLC/A protein. Immunohistochemistry for cleaved SNAP-25 was negative, and purinergic and nitrergic antagonists partially and totally reversed the sensory inhibition, respectively. These data suggest that the BoNT/A inhibition of sensory nerve activity in this assay is not due to the classical well-characterised 'double-receptor' mechanism of BoNT/A, is independent of SNAP25 cleavage and involves nitrergic and purinergic signalling mechanisms.

Porcine Acellular Nerve-Derived Hydrogel Improves Outcomes of Direct Muscle Neurotization in Rats

Background: The ability to reinnervate a muscle in the absence of a viable nerve stump is a challenging clinical scenario. Direct muscle neurotization (DMN) is an approach to overcome this obstacle; however, success depends on the formation of new muscle endplates, a process, which is often limited due to lack of appropriate axonal pathfinding cues. Objective: This study explored the use of a porcine nerve extracellular matrix hydrogel as a neuroinductive interface between nerve and muscle in a rat DMN model. The goal of the study was to establish whether such hydrogel can be used to improve neuromuscular function in this model. Materials and Methods: A common peroneal nerve-to-gastrocnemius model of DMN was developed. Animals were survived for 2 or 8 weeks following DMN with or without the addition of the hydrogel at the site of neurotization. Longitudinal postural thrust, terminal electrophysiology, and muscle weight assessments were performed to qualify and quantify neuromuscular function. Histological assessments were made to qualify the host response at the DMN site, and to quantify neuromuscular junctions (NMJs) and muscle fiber diameter. Results: The hydrogel-treated group showed a 132% increase in postural thrust at 8 weeks compared with that of the DMN alone group. This was accompanied by an 80% increase in the number of NMJs at 2 weeks, and 26% increase in mean muscle fiber diameter at 8 weeks. Conclusions: These results suggest that a nerve-derived hydrogel may improve the neuromuscular outcome following DNM.

Cannabis Use Disorder Is Associated With Longer In-Hospital Lengths of Stay, Higher Rates of Medical Complications, and Costs of Care Following Primary 1- to 2-Level Lumbar Fusion

STUDY DESIGN

Retrospective case-control study.

OBJECTIVES

The purpose of this study is to assess whether cannabis use disorder (CUD) patients undergoing primary 1- to 2-level lumbar fusion (1-2LF) for the treatment of degenerative lumbar spine disorders have higher rates of: (1) in-hospital lengths of stay (LOS), (2) medical complications, and (3) healthcare expenditures.

MATERIALS AND METHODS

A retrospective case-control study of the MSpine dataset of the PearlDiver claims from January 2007 to March 2018 was performed. Patients with CUD undergoing 1-2LF were queried and matched to a comparison group in a 1:5 ratio by age, sex, and various medical comorbidities yielding 22, 815 patients within the study (CUD = 3805; control = 19 010). Outcomes analyzed included LOS, 90-day medical complications, and costs. A P-value less than .004 was considered significant.

RESULTS

This study found CUD patients undergoing primary 1-2LF experience longer in-hospital LOS (4- vs. 3-days, P < .0001). Additionally, CUD patients were found to have significantly higher frequency and odds-ratios (OR) (31.88 vs. 18.01% OR: 1.41, P < .0001) of adverse events within ninety days following their procedure. CUD patients also had significantly higher day of surgery ($18,946.79 vs. $15,691.02, P < .0001) and 90 days healthcare expenditures ($21,469.01 vs. $19,556.71, P < .0001).

CONCLUSION

Patients with CUD can prepare for increased LOS, complications, and costs following primary 1-2LF. The study can be used to educate these patients of the potential outcomes following their procedure.

Forearm Lipoma Causing PIN Compression: Literature Review and Meta-Analysis of Predictors for Motor Recovery

BACKGROUND

Lipomas are a rare cause of posterior interosseous nerve (PIN) compression. A systematic review of predictors for motor recovery has not been performed. This study sought to evaluate whether patient or lipoma characteristics are associated with motor recovery and could be used to determine when immediate tendon transfers at the time of excision should be performed.

METHODS

Articles describing patients with forearm lipomas resulting in PIN compression with motor weakness were included. Patient age, gender, symptom duration, laterality and largest dimension of lipoma, surgical intervention, and motor recovery were identified. Article quality was assessed via the Methodological Index for Non-Randomized Studies criteria.

RESULTS

Thirty articles reporting on 34 patients were identified. Average age was 58.2 years. Average largest lipoma dimension was 5.7 cm. All patients underwent lipoma removal, and 2 had concomitant tendon transfers. In all, 73.5% of patients had complete motor recovery at an average of 9.7 months. Patient age and largest dimension of lipoma, and duration of symptoms were not significant predictors of motor recovery. Symptom duration was a significant predictor of motor recovery in binary regression, particularly if < 18 months.

CONCLUSIONS

The majority of patients with PIN weakness secondary to lipoma are likely to have complete motor recovery after excision alone. Concomitant tendon transfers should be considered for patients symptomatic for greater than 18 months. Further, adequately powered, studies are required to stratify risk factors and evaluate other modalities to identify the minority of patients who would benefit from immediate tendon transfer.

Common fibular nerve palsy due to the Fabella: A review

One of the most common nerve palsies - common fibular nerve palsy - can be caused by the variant small sesamoid bone in the posterolateral compartment of the knee joint known as the fabella. We compared and reviewed all reported cases of common fibular nerve palsy due to fabellae in the English literature. Compression can develop spontaneously or post-surgically (total knee arthroplasty). Symptoms progress rapidly to complete foot drop. Among all the cases reviewed, 68.42% were males with a median age of 39.39 years. Fabella compression was more common in the left common fibular nerve (CFN) (63.16%). Both big (23 × 20 × 16 mm) and small (5 × 5 mm) fabellae can be responsible for compression. While diagnosis can be problematic, the treatment (either surgical fabellectomy or conservative) is relatively easy and brings quick improvement.

Platelet-Rich Plasma Versus Corticosteroid Injections for the Treatment of Mild-to-Moderate Carpal Tunnel Syndrome: A Markov Cost-Effectiveness Decision Analysis

BACKGROUND

Platelet-rich plasma (PRP) or corticosteroid injections may be used to conservatively treat mild-to-moderate carpal tunnel syndrome (CTS). We evaluated the cost-effectiveness of PRP injections versus corticosteroid injections for the treatment of mild-to-moderate CTS.

METHODS

Markov modeling was used to analyze the base-case 45-year-old patient with mild-to-moderate CTS, unresponsive to conservative treatments, never previously treated with an injection or surgery, treated with a single injection of PRP, or methylprednisolone/triamcinolone 40 mg/mL. Transition probabilities were derived from level-I/II studies, utility values from the Tufts University Cost-Effectiveness Analysis Registry reported using visual analog scale (VAS), Boston Carpal Tunnel Questionnaire Symptom severity (BCTQ-S), and Boston Carpal Tunnel Questionnaire Functional status (BCTQ-F), and costs from Medicare, published studies, and industry. Analyses were performed from healthcare/societal perspectives. Outcomes were incremental cost-effectiveness ratios (ICER) and net monetary benefits (NMB). Willingness-to-pay thresholds were $50 000 and $100 000. Deterministic/probabilistic sensitivity analyses were performed.

RESULTS

From a healthcare perspective, compared to PRP injections, the ICER for corticosteroid injections measured by VAS: -$13.52/quality-adjusted-life-years (QALY), BCTQ-S: -$11.88/QALY, and BCTQ-F: -$16.04/QALY. PRP versus corticosteroid injections provided a NMB measured by VAS: $428 941.12 versus $375 788.21, BCTQ-S: $417 115.09 versus $356 614.18, and BCTQ-F: $421 706.44 versus $376 908.45. From a societal perspective, compared to PRP injections, the ICER for corticosteroid injections measured by VAS: -$1024.40/QALY, BCTQ-S: -$899.95/QALY, and BCTQ-F: -$1215.51/QALY. PRP versus corticosteroid injections provided a NMB measured by VAS: $428 171.63 versus $373 944.39, BCTQ-S: $416 345.61 versus $354 770.36, and BCTQ-F: $420 936.95 versus $375 064.63.

CONCLUSIONS

PRP injections were more cost-effective than methylprednisolone/triamcinolone injections from healthcare and societal perspectives for mild-to-moderate CTS.

Are Patient Demographics and Payor Status Associated With Practice Patterns in the Surgical Management of Carpal Tunnel Syndrome?

BACKGROUND

Open carpal tunnel release (OCTR) and endoscopic carpal tunnel release (ECTR) are the 2 operative approaches used to treat carpal tunnel syndrome (CTS). This study aims to identify whether differences between OCTR and ECTR rates exist, and, if so, are these differences associated with patient demographics or hospital characteristics.

METHODS

The 2018 Nationwide Ambulatory Surgery Sample (NASS) was filtered for patient encounters including either OCTR or ECTR operations. All patients undergoing either OCTR or ECTR were included, regardless of surgical specialty. Patient demographics and hospital characteristics data, provided and predefined by the NASS database, were collected and compared between the 2 treatment groups.

RESULTS

A total of 180 740 patient encounters were collected for both procedure types (OCTR: 62.4% women, mean age, 58 years; ECTR: 62.2% women, mean age, 58 years). Patients from lower income zip codes were more likely to undergo OCTR (P < .001). Patients either self-paying (P < .008) or covered by Medicare (P < .001) or Medicaid insurance (P < .001) were also more likely to undergo OCTR. In contrast, patients who received care at academic centers and centers with >300 beds were more likely to undergo ECTR (P < .001). Patients <65 years old were more likely to undergo ECTR (P < .001), and patients > 75 years old were more likely to undergo OCTR (P < .001). In addition, ECTR was found to be more expensive, with average total charges $1568 greater than charges for OCTR (P < .001).

CONCLUSIONS

Significant differences exist in treatment strategies for CTS and are related to patient income, location, and primary payor status. Differences in OCTR and ECTR rates are also present, and are related to the size and academic status of hospitals.

Indolent Multinodular Synovial Sarcoma of Peripheral Nerves Mimicking Schwannoma: A Case Report and Literature Review

BACKGROUND/AIM

Most cases of synovial sarcoma (SS) are aggressive and large-sized; only few show indolent behavior, having a small size. Nerves are rare sites of SS occurrence. An atypical case of SS can lead to its misdiagnosis as a benign tumor and delay its treatment.

CASE REPORT

Here, we report a case of primary SS of indolent multinodular synovial sarcoma of peripheral nerves. Considering the clinical and imaging findings at the first visit, we suspected a benign tumor and continued careful follow-up. Three years later, marginal resection was performed and SS was suspected. We then performed an additional wide resection using a free flap. Histopathologically, the proximal tumor showed a diffuse proliferation of spindle cells without pleomorphism, whereas the distal tumor showed a similar histology with more hypercellularity. Additional wide-resection specimens showed remnant tumors derived from the peripheral nerve. Immunohistochemistry (IHC) showed positive staining for SS18:SSX and SSX in both tumors and fluorescence in situ hybridization showed positive staining for the SS18 split in both tumors. Finally, SS of the peripheral nerve was diagnosed. Owing to FNCLCC grade 2 tumor and tumor size, adjuvant chemotherapy was not performed.

CONCLUSION

In cases of SS or other sarcomas with atypical clinical courses, with imaging findings mimicking benign tumors, we recommend marginal resection along with pathological examination for correct diagnosis.

Surgical and oncologic outcomes in dogs with malignant peripheral nerve sheath tumours arising from the brachial or lumbosacral plexus

Malignant peripheral nerve sheath tumours (MPNST) of a plexus nerve or nerve root cause significant morbidity and present a treatment challenge. The surgical approach can be complex and information is lacking on outcomes. The objective of this study was to describe surgical complication rates and oncologic outcomes for canine MPNST of the brachial or lumbosacral plexus. Dogs treated for a naïve MPNST with amputation/hemipelvectomy with or without a laminectomy were retrospectively analysed. Oncologic outcomes were disease free interval (DFI), overall survival (OS), and 1- and 2-year survival rates. Thirty dogs were included. The surgery performed was amputation alone in 17 cases (57%), and amputation/hemipelvectomy with laminectomy in 13 cases (43%). Four dogs (13%) had an intraoperative complication, while 11 dogs (37%) had postoperative complications. Histologic margins were reported as R0 in 12 dogs (40%), R1 in 12 dogs (40%), and R2 in five dogs (17%). No association was found between histologic grade and margin nor extent of surgical approach and margin. Thirteen dogs (46%) had recurrence. The median DFI was 511 days (95% CI: 140-882 days). The median disease specific OST was 570 days (95% CI: 467-673 days) with 1- and 2-year survival rates of 82% and 22% respectively. No variables were significantly associated with recurrence, DFI, or disease specific OST. These data show surgical treatment of plexus MPNST was associated with a high intra- and postoperative complication rate but relatively good disease outcomes. This information can guide clinicians in surgical risk management and owner communication regarding realistic outcomes and complications.

The evaluation of tibial nerve using shear-wave elastography and ultrasound in patients with systemic sclerosis: A cross-sectional study

Objectives

The study aimed to evaluate stiffness and the cross-sectional area (CSA) of the tibial nerve (TN) using shear wave elastography (SWE) and ultrasound (US) and investigate the relationship of these with disease activity, quality of life, and severity of neuropathic pain in patients with systemic sclerosis (SSc).

Patients and methods

This cross-sectional study included 28 SSc patients (1 male, 27 females; mean age: 50±11 years; range, 28 to 67 years) and 22 age- and sex-matched healthy controls (4 males, 18 females; mean age: 48±6 years; range, 37 to 66 years) between March and April 2022. US and SWE were performed on the TN, and CSA and nerve stiffness were measured. The TN was examined by a radiologist, 4 cm proximal to the medial malleolus. A few days later, an evaluation was performed in the second session by a second observer to investigate inter-and intraobserver agreement. Interobserver agreement was evaluated using the intraclass correlation coefficient (ICC). The Scleroderma Health Assessment Questionnaire, European League Against Rheumatism European Scleroderma Trial and Research (EUSTAR) group activity index, and Douleur-Neuropathique 4 scores of the patients were evaluated. Correlations between the questionnaires and measurements of nerve stiffness and CSA were assessed.

Results

Patients with SSc had significantly higher stiffness and CSA values of the right TN compared to healthy controls (p<0.001 and p=0.015, respectively). The nerve stiffness values of the right TN were positively correlated with the EUSTAR activity index (p=0.004, r=0.552). The CSA of the left TN was larger in patients with SSc (21.3±4.9 mm2 ) than in controls (12.8±3.4 mm2 ), and the nerve elasticity was positively correlated with the EUSTAR activity index (p=0.001, r=0.618). The interobserver agreement was moderate to good for measuring stiffness and CSA of the TN (ICC were 0.660 and 0.818, respectively). There was a good to excellent intraobserver agreement for measuring stiffness and CSA of TN (ICC were 0.843 and 0.940, respectively).

Conclusion

The increased disease activity in patients with SSc is associated with TN involvement, which can be demonstrated by US and SWE.

Standardized protocol for quantification of nerve bundle density as a biomarker for endometriosis

Introduction

We propose a standardized protocol for measurement of nerve bundle density in endometriosis as a potential biomarker, including in deep endometriosis (DE), ovarian endometriomas (OMA) and superficial peritoneal endometriosis (SUP).

Methods

This was a prospective cohort of surgically excised endometriosis samples from Dec 1st 2013 and Dec 31st 2017 at a tertiary referral center for endometriosis in Vancouver, BC, Canada. Surgical data were available from linked patient registry. Protein gene product 9.5 (PGP9.5) was used to identify nerve bundles on immunohistochemistry. PGP9.5 nerve bundles were counted visually. To calculate nerve bundle density, PGP9.5 nerve bundle count was divided by the tissue surface area (total on the slide). All samples were assessed using NHS Elements software for semi-automated measurement of the tissue surface area. For a subset of samples, high power fields (HPFs) were also counted as manual measurement of the tissue surface area. Intraclass correlation was used to assess intra observer and inter observer reliability. Generalized linear mixed model (GLMM) with random intercepts only was conducted to assess differences in PGP9.5 nerve bundle density by endometriosis type (DE, OMA, SUP).

Results

In total, 236 tissue samples out of 121 participants were available for analysis in the current study. Semi-automated surface area measurement could be performed in 94.5% of the samples and showed good correlation with manually counted HPFs (Spearman's rho = 0.781, p < 0.001). To assess intra observer reliability, 11 samples were assessed twice by the same observer; to assess inter observer reliability, 11 random samples were blindly assessed by two observers. Intra observer reliability and inter observer reliability for nerve bundle density were excellent: 0.979 and 0.985, respectively. PGP9.5 nerve bundle density varied among samples and no nerve bundles could be found in 24.6% of the samples. GLMM showed a significant difference in PGP9.5 nerve bundle density between the different endometriosis types (X2 = 87.6, P < 0.001 after adjusting for hormonal therapy, with higher density in DE and SUP in comparison to OMA).

Conclusion

A standardized protocol is presented to measure PGP9.5 nerve bundle density in endometriosis, which may serve as a biomarker reflecting local neurogenesis in the endometriosis microenvironment.

Unveiling the LncRNA-miRNA-mRNA Regulatory Network in Arsenic-Induced Nerve Injury in Rats through High-Throughput Sequencing

Arsenic is a natural toxin which is widely distributed in the environment, incurring diverse toxicities and health problems. Previous studies have shown that long non-coding RNAs (LncRNAs) are also reported to contribute to As-induced adverse effects. LncRNAs are involved in the development of nerve injury, generally acting as sponges for microRNAs (miRNAs). This study aimed to investigate the competitive endogenous RNA (ceRNA) regulatory networks associated with arsenic-induced nerve damage. A total of 40 male Wistar rats were exposed to different doses of arsenic for 12 weeks, and samples were collected for pathological observation and high-throughput sequencing. The ceRNA network was constructed using Cytoscape, and key genes were identified through the PPI network and CytoHubba methods. A real-time quantitative PCR assay was performed to validate gene expression levels. The results showed that subchronic exposure to arsenic in drinking water resulted in pathological and ultrastructural damage to the hippocampal tissue, including changes in neuron morphology, mitochondria, and synapses. Exposure to arsenic results in the dysregulation of LncRNA and mRNA expression in the hippocampal tissues of rats. These molecules participated in multiple ceRNA axes and formed a network of ceRNAs associated with nerve injury. This study also verified key molecules within the ceRNA network and provided preliminary evidence implicating the ENRNOT-00000022622-miR-206-3p-Bdnf axis in the mechanism of neural damage induced by arsenic in rats. These findings provide novel insights into the underlying mechanism of nervous system damage induced by arsenic exposure.

Preoperative evaluation of nerve transfer recipients after spinal cord injury using stimulated manual muscle testing

Nerve transfer after spinal cord injury has become increasingly popular. Accurate preoperative identification of lower motor neuron involvement in potential recipient nerves is critical. Electrodiagnostic testing has been shown to correlate with intraoperative findings; however, it is time-consuming, costly and may not be readily available. Stimulated manual muscle testing is an alternative diagnostic approach. It is inexpensive and easily done by the surgeon or therapist in the office; however, correlation with intraoperative stimulation has not been reported. A retrospective review was conducted for patients who underwent nerve transfer for tetraplegia with recorded preoperative stimulated manual muscle testing and intraoperative stimulation results. Nine patients including 37 nerve transfers were included. Of the 37 nerve transfers, 36 were accurately graded preoperatively by stimulated manual muscle testing. Stimulated manual muscle testing had a sensitivity of 89%, specificity of 100%, positive predictive value of 100% and a negative predictive value of 97%. This study supports stimulated manual muscle testing for preoperative distinction between upper versus lower motor neuron injuries.Level of evidence: IV.

Incidence and Risk Factors for Revision Within 1 Year of Primary Carpal Tunnel Release

BACKGROUND

The annual volume of carpal tunnel release (CTR) in the United States has been estimated to be 577 000 per year. Our objectives were to evaluate the incidence and risk factors for revision CTR within 1 year of primary CTR.

METHODS

We identified all adult patients undergoing primary CTR from October 2015 to September 2019 in the New York Statewide Planning and Research Cooperative System database using Current Procedural Terminology (CPT) codes. We used the CPT modifier codes to determine laterality of index and revision procedures. We estimated multivariable hierarchical logistic regression models to evaluate risk factors for revision CTR within 1 year.

RESULTS

Of the 80 423 primary CTR procedures, 178 (0.22%) underwent a revision CTR within 1 year of the index surgery. The mean (SD) age of the entire cohort was 58.69 (14.43) years, 61.1% were women, 73.2% were non-Hispanic white, 42.9% were covered through private insurance, and 9.5% had diabetes mellitus. Workers' compensation insurance (odds ratio [OR] = 1.83, 95% confidence interval [CI], 1.13-2.98, P = .02) and simultaneous bilateral CTR (OR = 14.91, 95% CI, 9.62-23.12, P < .001) were associated with revision CTR within 1 year of the index procedure. No models demonstrated an association between endoscopic technique or surgeon volume and revision CTR.

CONCLUSIONS

The incidence of revision CTR within 1 year was lower than that previously reported. Patients covered by workers' compensation and those undergoing simultaneous bilateral CTR had higher likelihood of a revision CTR within 1 year, whereas endoscopic technique and surgeon volume were not associated with revision CTR within 1 year.

Time-varying changes in median nerve deformation and position in response to quantified pinch and grip forces

The ability of the median nerve (MN) to adapt in response to altered carpal tunnel conditions is important to mitigate compressive stress on the nerve. We assessed changes in MN deformation and position throughout the entire time course of hand force exertions. Fourteen right-handed participants ramped up force from 0% to 50% of maximal voluntary force (MVF) before ramping force back down in three different hand force exertion tasks (pulp pinch, chuck pinch, power grip). Pinch and grip forces were measured with a digital dynamometer, which were time synchronized with transverse carpal tunnel images obtained via ultrasound. Ultrasound images were extracted in 10% increments between 0% and 50% MVF while ramping force up (loading phase) and down (unloading phase). MN deformation and position relative to the flexor digitorum superficialis tendon of the long finger were assessed in concert. During loading, the nerve became more circular while displacing dorsally and ulnarly. These changes primarily occurred at the beginning of the hand force exertions while ramping force up from 0% to 20%, with very little change between 20% and 50% MVF. Interestingly, deformation and position changes during loading were not completely reversed during unloading while ramping force down. These findings indicate an initial reorganization of carpal tunnel structures. Mirrored changes in nerve deformation and position may also reflect strain-related characteristics of adjoining subsynovial connective tissue. Regardless, time-varying changes in nerve deformation and position appear to be an important accommodative mechanism in the healthy carpal tunnel in response to gripping and pinching tasks.

Surgical Outcomes, Trends, and Risk Factors of Distal Triceps Repairs

BACKGROUND

Distal triceps ruptures are rare, and complete ruptures are commonly treated with surgery. Studies of patients in small cohorts with distal triceps tear have reported outcomes and risk factors; however, large-scale data are scant. This study seeks to determine current trends, outcomes, and risk factors of distal triceps tears.

METHODS

Within a large insurance claims database, distal triceps repair patients were identified through Current Procedural Terminology coding with concomitant distal triceps International Classification of Diseases, 9th Revision/10th Revision diagnosis codes and 1-year active status before and after surgery. Demographics, total costs, 90-day complications, and revision rates within 1 year of index surgery were analyzed. Logistic regression was performed for revision and complication rates using sex, age, and comorbidities (anabolic steroid use, diabetes, ischemic heart disease, tobacco use, rheumatoid arthritis, and chronic kidney disease).

RESULTS

A total of 8143 patients were included in the cohort. Male patients and patients aged 40 to 59 years comprised most of the study population. The postoperative complication rate was 5.8%, and the 1-year revision rate was 2.6%. Male sex, age >60 years, ischemic heart disease, rheumatoid arthritis, and chronic kidney disease were statistically significant risk factors for higher 90-day complication rates. Anabolic steroid use significantly increased the risk of surgical revision.

CONCLUSIONS

Distal triceps repairs in this large cohort study occur most frequently in men aged 40 to 59 years. Complications are generally low, with age >60 years, male sex, ischemic heart disease, rheumatoid arthritis, and chronic kidney disease as risk factors for 90-day complications and prior anabolic steroid use as a risk factor for 1-year revision surgery. This information can help to improve education and expectations of this procedure.

Optimizing Noninvasive Vagus Nerve Stimulation for Systemic Lupus Erythematosus: Protocol for a Multicenter Randomized Controlled Trial

BACKGROUND

Systemic lupus erythematosus is a chronic, multisystem, inflammatory disease of autoimmune etiology occurring predominantly in women. A major hurdle to the diagnosis, treatment, and therapeutic advancement of this disease is its heterogeneous nature, which presents as a wide range of symptoms such as fatigue, fever, musculoskeletal involvement, neuropsychiatric disorders, and cardiovascular involvement with varying severity. The current therapeutic approach to this disease includes the administration of immunomodulatory drugs that may produce unfavorable secondary effects.

OBJECTIVE

This study explores the known relationship between the autonomic nervous system and inflammatory pathways to improve patient outcomes by treating autonomic nervous system dysregulation in patients via noninvasive vagus nerve stimulation. In this study, data including biomarkers, physiological signals, patient outcomes, and patient quality of life are being collected and analyzed. After completion of the clinical trial, a computer model will be developed to identify the biomarkers and physiological signals related to lupus activity in order to understand how they change with different noninvasive vagus nerve stimulation frequency parameters. Finally, we propose building a decision support system with integrated noninvasive wearable technologies for continuous cardiovascular and peripheral physiological sensing for adaptive, patient-specific optimization of the noninvasive vagus nerve stimulation frequency parameters in real time.

METHODS

The protocol was designed to evaluate the efficacy and safety of transauricular vagus nerve stimulation in patients with systemic lupus erythematosus. This multicenter, national, randomized, double-blind, parallel-group, placebo-controlled study will recruit a minimum of 18 patients diagnosed with this disease. Evaluation and treatment of patients will be conducted in an outpatient clinic and will include 12 visits. Visit 1 consists of a screening session. Subsequent visits up to visit 6 involve mixing treatment and evaluation sessions. Finally, the remaining visits correspond with early and late posttreatment follow-ups.

RESULTS

On November 2022, data collection was initiated. Of the 10 participants scheduled for their initial appointment, 8 met the inclusion criteria, and 6 successfully completed the entire protocol. Patient enrollment and data collection are currently underway and are expected to be completed in December 2023.

CONCLUSIONS

The results of this study will advance patient-tailored vagus nerve stimulation therapies, providing an adjunctive treatment solution for systemic lupus erythematosus that will foster adoption of technology and, thus, expand the population with systemic lupus erythematosus who can benefit from improved autonomic dysregulation, translating into reduced costs and better quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05704153; https://clinicaltrials.gov/study/NCT05704153.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/48387.

Super-high procoagulant activity of gecko thrombin: A gift from sky dragon

AIMS

Gecko, the "sky dragon" named by Traditional Chinese Medicine, undergoes rapid coagulation and scarless regeneration following tail amputation in the natural ecology, providing a perfect opportunity to develop the efficient and safe drug for blood clotting. Here, gecko thrombin (gthrombin) was recombinantly prepared and comparatively studied on its procoagulant activity.

METHODS

The 3D structure of gthrombin was constructed using the homology modeling method of I-TASSER. The active gthrombin was prepared by the expression of gecko prethrombin-2 in 293 T cells, followed by purification with Ni2+ -chelating column chromatography prior to activation by snake venom-derived Ecarin. The enzymatic activities of gthrombin were assayed by hydrolysis of synthetic substrate S-2238 and the fibrinogen clotting. The vulnerable nerve cells were used to evaluate the toxicity of gthrombin at molecular and cellular levels.

RESULTS

The active recombinant gthrombin showed super-high catalytic and fibrinogenolytic efficiency than those of human under different temperatures and pH conditions. In addition, gthrombin made nontoxic effects on the central nerve cells including neurons, contrary to those of mammalian counterparts, which contribute to neuronal damage, astrogliosis, and demyelination.

CONCLUSIONS

A super-high activity but safe procoagulant candidate drug was identified from reptiles, which provided a promising perspective for clinical application in rapid blood clotting.

Sonographic Phrenic Nerve Changes in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects both the upper and lower motor neurons in the nervous system, causing muscle weakness and severe disability. The progressive course of the disease reduces the functional capacity of the affected patients, limits daily activities, and leads to complete dependence on caregivers, ultimately resulting in a fatal outcome. Respiratory dysfunction mostly occurs later in the disease and is associated with a worse prognosis. Forty-six participants were included in our study, with 23 patients in the ALS group and 23 individuals in the control group. The ultrasound examination of the phrenic nerve (PN) was performed by two authors using a high-resolution "Philips EPIQ 7" ultrasound machine with a linear 4-18 MHz transducer. Our study revealed that the phrenic nerve is significantly smaller on both sides in ALS patients compared to the control group (p < 0.001). Only one significant study on PN ultrasound in ALS, conducted in Japan, also showed significant results (p < 0.00001). These small studies are particularly promising, as they suggest that ultrasound findings could serve as an additional diagnostic tool for ALS.

Where Does Ultrasound Fit in the Diagnostic Algorithm for Cubital Tunnel Syndrome?

BACKGROUND

Ultrasound (US) has emerged as a promising supplement to electrodiagnostic studies (EDX) in the diagnosis of cubital tunnel syndrome (CuTS) and has potential to be performed by novice operators. Our objective is to understand the discrepancies in assessment between the two modalities and to assess the utility of US in CuTS diagnosis by a novice operator.

METHODS

Patients who presented to a single tertiary academic medical center and clinically diagnosed with CuTS were prospectively enrolled. Electrodiagnostic studies were performed along with US measurements of the cross-sectional area (CSA) of the ulnar nerve by both a board-certified physiatrist and novice operator. Electrodiagnostic study and US outcomes were compared among four diagnostic impression groups: EDX-/US-, EDX+/US-, EDX-/US+, and EDX+/US+.

RESULTS

Sixteen patients were classified as abnormal by both EDX and US, 14 were classified abnormal by US only, 3 were classified abnormal by EDX only, and 6 were classified normal by both EDX and US (P = .008, K = 0.14). The EDX+/US+ group had a significantly reduced sensory amplitude compared with the EDX-/US+ (P = .04) group. Diagnostic classifications between a board-certified physiatrist and novice operator were in moderate agreement (K = 0.58, P = .08).

CONCLUSIONS

Ultrasound detected a greater proportion of patients as abnormal than EDX. A subset of patients with clinical diagnoses of CuTS had normal sensory amplitudes but increased maximum nerve CSAs. Competency in US may be easily acquired with minimal training, suggesting its potential to be extended for use by other members of the health care team.

The Role of Surgery in the Management of Radiation-Induced Brachial Plexopathy

Radiation-induced brachial plexopathy (RIBP) is a rare long-term complication of radiation therapy often causing pain, motor deficit, and overall quality of life reduction for affected patients. While a standard treatment for RIBP is yet to be established, management consists mostly of symptom management through the use of medications and physical therapy. There is a lack of evidence regarding the efficacy of surgical treatment. Omentoplasties and other vascularized flaps are commonly discussed options for eliminating neuropathic pain associated with RIBP. However, these approaches show no meaningful improvement in motor function. While limited, current literature suggests that nerve transfers may be an option for relief of neuropathic pain as well as restoration of motor function. This review of literature explores the options available to those affected by RIBP with a focus on the role of surgery.

The Effect of Surgical Timing on Upper Extremity Nerve Repair

BACKGROUND

The purpose of this study was to evaluate the association between timing of nerve repair and the ability to perform a primary nerve repair versus a bridge repair requiring the use of allograft, autograft, or a conduit in lacerated upper extremity peripheral nerve injuries.

METHODS

This is a retrospective case-control study of patients who underwent upper extremity nerve repair for lacerated peripheral nerves identified by Current Procedural Terminology codes. Timing of injury and surgery, as well as other information such as demographic information, mechanism of injury, site of injury, and type of nerve repair, was recorded. The odds of a patient requiring bridge repair based on the duration of time between injury and surgery was evaluated using logistic regression.

RESULTS

A total of 403 nerves in 335 patients (mean age 35.87 ± 15.33 years) were included. In all, 241 nerves were primarily repaired and 162 required bridge repair. Patients requiring bridge repair had a greater duration between injury and surgery compared with patients who underwent primary repair. Furthermore, the nerves requiring bridge repair were associated with a greater gap compared with the nerves repaired primarily. Based on logistic regression, each 1-day increase in duration between injury and surgery was associated with a 3% increase in the odds of requiring bridge repair.

CONCLUSIONS

There is no defined critical window to achieve a primary nerve repair following injury. This study demonstrated that nerve injuries requiring bridge repair were associated with a significantly greater delay to surgery.

Older Patients Demonstrate PROMIS Outcomes Comparable to Younger Cohorts After Carpal Tunnel Release

BACKGROUND

The utility of Patient-Reported Outcomes Measurement Information System (PROMIS) in monitoring clinical progress after carpal tunnel release (CTR) in patients of different ages remains unknown. We sought to evaluate early PROMIS scores in elderly patients (ie, those aged ≥65 years) after CTR and compare those with all younger patients after CTR.

METHODS

Patients presenting to a single academic medical center for CTR between September 2018 and January 2020 completed PROMIS physical function (PF), pain interference (PI), and upper extremity (UE) computer adaptive tests and answered a single 5-point Likert-scale question evaluating subjective changes in their condition following CTR. Patients were divided into 3 age groups, and preoperative and postoperative PROMIS scores were compared.

RESULTS

In all, 214 patients fit inclusion criteria: 86 aged 18-54 years, 71 aged 55-64 years, and 57 aged ≥65 years. Subjective improvement was reported in 70.9% (n = 61), 84.5% (n = 60), and 71.9% (n = 41) of patients aged ≤54, 55-64, and ≥65 years, respectively. Patients aged ≤54 years showed significantly worse UE scores (P = .02), whereas those aged 55-64 years demonstrated significant worsening in all 3 PROMIS domains (P < .01). Patients aged ≥65 years who reported subjective improvement after CTR demonstrated significant improvement in PI scores (P = .03), whereas significant worsening of all PROMIS scores was observed in the subset of patients aged 55-64 years who reported subjective improvement (P < .01, .04, and .04 for PF, PI, and UE, respectively).

CONCLUSIONS

Younger patients showed worsening in PROMIS scores after CTR, whereas elderly patients did not show similar magnitude reductions in PROMIS scores. Moreover, the subset of elderly patients endorsing subjective improvement after CTR had reduced PI scores, consistent with less postoperative pain limitations.

Reoperation Following Zone II Flexor Tendon Repair

BACKGROUND

The goal of zone II flexor tendon surgery is to perform a repair with sufficient strength to withstand the forces encountered during rehabilitation. Postoperative rerupture and adhesion formation may lead to reoperation. This study aimed to determine the factors associated with reoperation after primary zone II flexor tendon repair.

METHODS

In this retrospective case series, a total of 252 fingers in 201 patients underwent zone II flexor tendon repair. A medical record review was performed to collect data regarding patient demographics, injury and treatment characteristics and postoperative complications including reoperation. Reoperation was defined as any unplanned surgical procedure performed after initial flexor tendon repair.

RESULTS

There were 49 fingers (19%) in 42 patients that underwent reoperation at a median of 5.5 (interquartile range: 2.8-7.9) months. Older age, workers' compensation, and a Kessler-type repair of the flexor digitorum profundus were independently associated with reoperation.

CONCLUSIONS

In vitro studies suggest that Kessler-type repairs are inferior compared with other suture configurations. Our study demonstrates a clinical correlation to these biomechanical studies. Our results suggest that Kessler-type repairs are inferior compared with non-Kessler-type repairs, due to postoperative complications requiring secondary surgeries.

Alignment behavior of nerve, vascular, muscle, and intestine cells in two- and three-dimensional strategies

By harnessing structural hierarchical insights, plausibly simulate better ones imagination to figure out the best choice of methods for reaching out the unprecedented developments of the tissue engineering products as a next level. Constructing a functional tissue that incorporates two-dimensional (2D) or higher dimensions requires overcoming technological or biological limitations in order to orchestrate the structural compilation of one-dimensional and 2D sheets (microstructures) simultaneously (in situ). This approach enables the creation of a layered structure that can be referred to as an ensemble of layers or, after several days of maturation, a direct or indirect joining of layers. Here, we have avoided providing a detailed methodological description of three-dimensional and 2D strategies, except for a few interesting examples that highlight the higher alignment of cells and emphasize rarely remembered facts associated with vascular, peripheral nerve, muscle, and intestine tissues. The effective directionality of cells in conjunction with geometric cues (in the range of micrometers) is well known to affect a variety of cell behaviors. The curvature of a cell's environment is one of the factors that influence the formation of patterns within tissues. The text will cover cell types containing some level of stemness, which will be followed by their consequences for tissue formation. Other important considerations pertain to cytoskeleton traction forces, cell organelle positioning, and cell migration. An overview of cell alignment along with several pivotal molecular and cellular level concepts, such as mechanotransduction, chirality, and curvature of structure effects on cell alignments will be presented. The mechanotransduction term will be used here in the context of the sensing capability that cells show as a result of force-induced changes either at the conformational or the organizational levels, a capability that allows us to modify cell fate by triggering downstream signaling pathways. A discussion of the cells' cytoskeleton and of the stress fibers involvement in altering the cell's circumferential constitution behavior (alignment) based on exposed scaffold radius will be provided. Curvatures with size similarities in the range of cell sizes cause the cell's behavior to act as if it was in an in vivo tissue environment. The revision of the literature, patents, and clinical trials performed for the present study shows that there is a clear need for translational research through the implementation of clinical trial platforms that address the tissue engineering possibilities raised in the current revision. This article is categorized under: Infectious Diseases > Biomedical Engineering Neurological Diseases > Biomedical Engineering Cardiovascular Diseases > Biomedical Engineering.

On the Road Again: Return to Driving Following Minor Hand Surgery

BACKGROUND

Patient return-to-driving following minor hand surgery is unknown. Through daily text message surveys, we sought to determine return-to-driving after minor hand surgery and the factors that influence return-to-driving.

METHODS

One hundred five subjects undergoing minor hand surgery received daily text messaging surveys postoperatively to assess: (1) if they drove the day before and if so; (2) whether they wore a cast, sling, or splint. Additional patient-, procedure-, and driving-related data were collected.

RESULTS

More than half of subjects, 54 out of 105, returned to driving by the end of postoperative day #1. While patient-related factors had no effect on return-to-driving, significant differences were seen in anesthesia type, procedure laterality, driving assistance, and distance. Return-to-driving was significantly later for subjects who had general anesthetic compared to wide awake local anesthetic with no tourniquet (4 ± 4 days vs 1 ± 3 days, P = 0.020), as well as for bilateral procedures versus unilateral procedures (5 ± 5 days vs 1 ± 3 days, P = 0.046). Lack of another driver and driving on highways led to earlier return-to-driving (P = 0.040 and, P = 0.005, respectively).

CONCLUSIONS

Most patients rapidly return to driving after minor hand surgery. Use of general anesthetic and bilateral procedures may delay return-to-driving. Confidential real-time text-based surveys can provide valuable information on postoperative return-to-driving and other patient behaviors.

Is Radiofrequency Ablation Superior to Intra-Articular Injections for the Treatment of Symptomatic Knee Osteoarthritis?-A Systematic Review

The radiofrequency ablation (RFA) is considered a valid, minimally invasive treatment modality for the management of symptomatic knee osteoarthritis (OA). The aim of this study was to compare the outcomes of RFA with that of commonly used intra-articular injections for the persistent knee pain due to OA. Medline/Pubmed and Scopus databases were systematically searched up to April 2023 to identify studies comparing the effect of RFA and intra-articular injections (IAIs) on knee OA. Nine studies including 899 patients fulfilled the eligibility criteria and were included in the systematic review. The RFA procedure was related with improved knee pain relief compared to IAIs at 3-, 6- and 12-month follow-up (p < 0.001). Similarly, functional improvement was greater in RFA treatment than that observed after hyaluronic acid (HA), steroid or platelet-rich plasma (PRP) injections (Visual Analogue Scale p < 0.001, Numeric Rating Scale p = 0.019, Western Ontario and McMaster University Osteoarthritis Index p = 0.012). The overall procedural complication rate of RFA was 10.2% and was higher than steroid (p = 0.023) and PRP (p = 0.017) injections. However, no severe adverse events were reported. For patients with symptomatic knee OA, RFA seems to be more effective than IAIs in alleviating pain and improving joint function, despite the relatively higher incidence of non-serious adverse events. However, due to the limited number of studies and patients, this result should be interpreted with caution and not be generalized to the entire knee OA population.

How Institution of the Sup-ER Protocol in a Clinic Changed Procedure Patterns in Upper Brachial Plexus (Erb's Type) Birth Injuries

BACKGROUND

For children with upper brachial plexus birth injury (BPBI; C5, C6, ±C7 roots), most clinics first recommend nonsurgical treatment followed by primary and/or secondary surgical interventions in selected patients. Since 2008, we have used an infant shoulder repositioning protocol (supination-external rotation [Sup-ER]) designed to prevent shoulder internal rotation contracture and its potential effects on the shoulder joint. This study characterizes our clinic's current choice, number, and timing of primary and secondary procedural interventions (including Botox) and compares Sup-ER protocol patients with those of our historical controls.

METHODS

The records of all patients with upper BPBI who underwent procedures from 2001 to 2018 were retrospectively reviewed and grouped into a historical (2001-2007, n = 20) and recent (2008-2018, n = 23) cohort. Patient demographics, procedure types and timing, and functional outcomes were collected and analyzed.

RESULTS

Since the 2008 institution of the Sup-ER protocol, fewer brachial plexus exploration and grafting (BPEG) surgeries were performed and none in later infancy, where nerve transfers were preferred. There were more and earlier Botox injections. There were fewer tendon transfers, and the preoperative indications were from a higher level of function.

CONCLUSIONS

We now see fewer indications for BPEG surgeries overall. After the 3-month-age group, more direct nerve transfers are indicated instead of the BPEG surgery if nerve surgery is required at all. Shoulder tendon transfer rates have decreased. Humeral osteotomies are not seen in our recent group. Glenoid osteotomies within tendon transfers are rare in both groups.

Nerve Torsion as a Pattern of Parsonage-Turner Syndrome: Literature Review and Two Representative Cases

(1) Background: Parsonage-Turner Syndrome (PTS) is a rare peripheral nerve disease characterized by different degrees of nerve impairment. The recent development of nerve ultrasound has enabled the use of new data in the diagnosis of the disease. The aim of this study is to conduct a literature review about the ultrasound evaluation of PTS and present two clinical cases that are characteristic of the disease. (2) Methods: A review of the literature from the last 10 years on the topic containing data regarding nerve ultrasound was performed. In addition, two cases of patients on whom nerve ultrasound was performed at the first evaluation and at follow-up after the indicated treatment were described. (3) Results: The results of our review show that although it is defined as plexopathy, PTS is most often a form of multifocal neuropathy. We also report the most frequently used ultrasound classification and possible prognostic correlations and report our experience with the description of two paradigmatic clinical cases. (4) Conclusions: Further studies are needed to understand the true prognostic power of each degree of nerve impairment and the possible implications in clinical practice regarding treatment indications.

Toward peripheral nerve mechanical characterization using Brillouin imaging spectroscopy

Significance

Peripheral nerves are viscoelastic tissues with unique elastic characteristics. Imaging of peripheral nerve elasticity is important in medicine, particularly in the context of nerve injury and repair. Elasticity imaging techniques provide information about the mechanical properties of peripheral nerves, which can be useful in identifying areas of nerve damage or compression, as well as assessing the success of nerve repair procedures.

Aim

We aim to assess the feasibility of Brillouin microspectroscopy for peripheral nerve imaging of elasticity, with the ultimate goal of developing a new diagnostic tool for peripheral nerve injury in vivo.

Approach

Viscoelastic properties of the peripheral nerve were evaluated with Brillouin imaging spectroscopy.

Results

An external stress exerted on the fixed nerve resulted in a Brillouin shift. Quantification of the shift enabled correlation of the Brillouin parameters with nerve elastic properties.

Conclusions

Brillouin microscopy provides sufficient sensitivity to assess viscoelastic properties of peripheral nerves.