Ulnar Nerve Research Articles

Ulnar Nerve Management in Complex Elbow Dislocations: A Retrospective Monocentric Study

Background/Objectives: The ulnar nerve’s unique anatomy makes it vulnerable to complex elbow dislocations. Depending on the nature of the injury, the clinical treatment and outcomes related to the nerve may vary. Unfortunately, the current literature provides limited and fragmented information on managing the ulnar nerve and the incidence of neuropathy in complex elbow dislocations. This study aimed to determine the occurrence of ulnar nerve pain and its relationship with transposition. Methods: A retrospective evaluation was conducted on a consecutive series of 44 patients who underwent surgery for complex elbow dislocations. The average follow-up period was 29 months. Patients were categorized based on their condition (trans-olecranon fracture–dislocation, Terrible Triad, Monteggia-like lesions, and injuries not falling into the previous categories). The study assessed whether the ulnar nerve was released from the cubital tunnel and underwent transposition. Additionally, the study examined the number of patients experiencing ulnar pain in the postoperative period and its duration over time. All patients were also evaluated using the Mayo Elbow Performance Score (MEPS), Disabilities of Arm, Shoulder, and Hand (DASH) score, and Oxford Elbow Score (OES). Results: Patients who underwent simultaneous ulnar nerve transposition surgery with complex elbow dislocation showed a higher incidence of neuropathy. In these patients, the symptoms were less severe but lasted longer. MEPS, DASH, and OES did not show statistically significant differences between the two groups; however, they were slightly better for the group without ulnar nerve transposition. Conclusions: Surgeons should refrain from routinely transposing the ulnar nerve in complex elbow dislocations. However, further studies involving larger populations are necessary.

Clinical significance of upper arm motor nerve conduction velocity in cubital tunnel syndrome.

Retrograde denervation occurs in severe entrapment neuropathy. This study aimed to investigate changes in motor nerve conduction velocity (MNCV) at the upper arm, specifically proximal to the elbow, in cubital tunnel syndrome (CuTS) and to correlate these changes with preoperative severity and postoperative outcomes. We retrospectively reviewed 95 elbows with 81 patients with CuTS for preoperative severity, and then 67 elbows with 60 of these patients who underwent anterior subcutaneous transposition surgery for postoperative outcome, classified into favorable and unfavorable groups according to Messina grade. The reduction of upper arm MNCV was correlated with aging, decreased compound muscle action potentials of abductor digiti minimi muscle, loss of sensory nerve action potentials, and modified McGowan grade. Postoperative assessment revealed lower MNCV values in the "unfavorable" group compared to the "favorable" group at 1 month, 6 months, and the last follow up. At each time point, the optimal cut-off value of upper arm MNCV for predicting postoperative outcomes was 54.1 m/s. Upper arm MNCV might be a useful predictor of poor surgical outcome. Ulnar nerve MNCV at the upper arm should be measured alongside routine assessment of MNCV at the elbow and forearm, especially in clinically severe cases considering surgery.

Comparison of Subdural and Intracortical Recordings of Somatosensory Evoked Responses.

Micro-electrocorticography (µECoG) electrodes have emerged to balance the trade-off between invasiveness and signal quality in brain recordings. However, its large-scale applicability is still hindered by a lack of comparative studies assessing the relationship between ECoG and traditional recording methods such as penetrating electrodes. This study aimed to compare somatosensory evoked potentials (SEPs) through the lenses of a µECoG and an intracortical microelectrode array (MEA). The electrodes were implanted in the pig's primary somatosensory cortex, while SEPs were generated by applying electrical stimulation to the ulnar nerve. The SEP amplitude, signal-to-noise ratio (SNR), power spectral density (PSD), and correlation structure were analysed. Overall, SEPs resulting from MEA recordings had higher amplitudes and contained significantly more spectral power, especially at higher frequencies. However, the SNRs were similar between the interfaces. These results demonstrate the feasibility of using µECoG to decode SEPs with wide-range applications in physiology monitoring and brain-computer interfaces.

Morphological characteristics of rabbits’ carpal tunnel: Evaluation of its potential for carpal tunnel research

This study aimed to define the main anatomic components and describe the normal size and form of the carpal tunnel in rabbits using imaging techniques. It was also aimed to evaluate the potential of rabbits as an animal model for carpal tunnel research. The forelimbs of eight adult New Zealand rabbits were investigated using histology, magnetic resonance, and computed tomography. Two cadavers were used for anatomical dissection to support the findings. The carpal tunnel was examined at proximal and distal levels, and it was found that the flexor retinaculum is two-layered in rabbits. Both vascular nerve bundles, including the median nerve and the ramus palmaris of the ulnar nerve, were within two layers of it and passed through the carpal tunnel. The deep digital flexor, superficial digital flexor, and radial carpal flexor tendons were observed within the carpal tunnel. The flexor pollicis longus tendon is not found in rabbits. The area of the carpal tunnel narrowed towards the distal end in three methods, and its depth decreased in CT and MRI. The length of the accessory carpal bone determined this depth. The study found that rabbits' carpal tunnels are morphologically similar to those of humans compared to dogs. This situation is thought to pave the way for more accurate approaches to carpal tunnel research in rabbits.

Refining the Diagnosis and Treatment of Cubital Tunnel Syndrome: A Comprehensive Review of Anatomy and Surgical Approaches

Cubital tunnel syndrome (CuTS) is a prevalent but often under-recognized compressive neuropathy of the upper extremities, involving the entrapment of the ulnar nerve within the cubital tunnel at the elbow. CuTS is common, but remains relatively unfamiliar to many neurosurgeons compared to other neuropathies. It frequently presents with sensory disturbances and motor deficits in the hand, particularly affecting the ulnar digits, and it may be linked to specific usage patterns or even considered a form of neurotrauma. Its diagnosis typically involves a clinical assessment supplemented by imaging and electrophysiological studies to evaluate the extent of nerve involvement. While conservative management may be sufficient in the early stages, surgical intervention is often necessary for advanced cases, and various techniques offer differing outcomes. This review underscores the importance of a thorough anatomical understanding in guiding an accurate diagnosis and effective treatment, ultimately contributing to improved patient outcomes. These insights are essential for clinicians encountering the complexities of CuTS in diverse clinical scenarios.

A Comparative Study between Ultrasound-guided Concomitant Infraclavicular Plus Distal Median, Radial, and Ulnar Nerve Blockade Versus Infraclavicular Block Alone

Abstract Background: Peripheral nerve blocks can be used alone as the sole “surgical” anesthetic technique as the initial step in providing prolonged postoperative analgesia. There are studies, where accurate deposition of local anesthetic perineurally has the potential to improve the success rate and reduce the incidence of complications of the infraclavicular block. We hypothesized whether a combined block of the infraclavicular brachial plexus and distal median, radial, and ulnar nerves would accelerate upper extremity anesthesia compared with an infraclavicular block alone. Materials and Methods: This study was a prospective randomized control study conducted among 60 patients undergoing elective and emergency wrist and hand surgeries. A group of 30 patients received an infraclavicular block with 30 mL of a local anesthetic mixture containing 1% lignocaine with adrenaline and 0.25% bupivacaine from Group A. Group B received an infraclavicular block with 15 mL of local anesthetic mixture containing 1% lignocaine with adrenaline and 0.25% bupivacaine along with distal median, radial, and ulnar nerve blockade with 5 mL each of local anesthetic mixture containing 1% lignocaine with adrenaline and 0.25% bupivacaine. Pain score, assessment of sensory and motor functions, block performance time, and surgical anesthesia were observed. Results: The mean block performance time of Group A was 10.9 ± 1.1 min and Group B was 14.7 ± 0.5 min. The difference between the two groups’ block performance minutes was statistically significant (P < 0.001). The difference in the onset of the sensory block between the two groups was statistically significant (P < 0.001). The mean onset of motor blockade between the two groups was statistically very highly significant (P < 0.001). The mean of Group A was 5.0 ± 0.2 and Group B was 2.1 ± 0.4. Conclusion: From this study, we conclude that using an approximately equivalent dose of local anesthetics, combining ultrasound-guided infraclavicular block with distal median, radial, and ulnar nerve blockade shortens the onset time of sensory and motor block with improved block consistency compared to infraclavicular block alone.

Guillain-Barré syndrome with overlap between the finger drop variant and acute bulbar palsy: a case report

BackgroundGuillain-Barré syndrome (GBS) is a clinically heterogenous disease and encompasses several distinct clinical variants. Overlap between these variants can pose a diagnostic challenge. We report a case of finger drop variant and acute bulbar palsy overlap as an unusual manifestation of GBS.Case presentationAn 81-year-old man presented with dysarthria, dysphagia, and upper limb weakness. Neurological examination revealed impaired tongue protrusion, the finger drop sign, and diminished brachioradial and triceps muscle reflexes. Nerve conduction studies showed reduced amplitudes and decreased velocities in the median and ulnar nerves. Cerebrospinal fluid analysis revealed albuminocytological dissociation and an anti-ganglioside antibody study revealed positivity for GM1, asialo-GM1, GT1a, GD1b, and GQ1b. As GBS was suspected, we initiated intravenous immunoglobulin treatment, resulting in gradual improvement within the next 3 weeks.ConclusionTo the best of our knowledge, this is the first reported case of an overlap between the finger drop variant and acute bulbar palsy in GBS, highlighting the importance of considering GBS when patients present with a combination of atypical symptoms. Anti-ganglioside antibodies can be helpful and add diagnostic value in these complex cases.

Incidence of Elbow Injury Patterns in Japanese Adolescent Judo Players: Analysis from a Nationwide Insurance Database

Elbow injuries are common in judo, particularly among adolescents. This study investigated the incidence and patterns of three types of elbow injuries (sprain, dislocation, and fracture-dislocation) among Japanese adolescent judo players (12 to 18 years old) using data from a nationwide insurance database, covering the period from 2010 to 2019. A total of 4614 elbow injuries were recorded, with sprains being the most frequent (67.6% of cases). Female players had a 20% higher incidence of sprains than male players (6.8 vs. 5.4 per 1000 athlete-years). Severe injuries, such as dislocations and fracture-dislocations, were more common in high school players, with male middle school students exhibiting a higher rate of elbow fracture-dislocations (+15%) compared with female students. Elbow injuries frequently occurred during te-waza techniques, particularly seoi-nage, when players extended their arms to prevent being thrown. Peripheral nerve injuries, predominantly ulnar nerve injuries, accompanied elbow dislocations in 74% of the cases. This study highlights the importance of proper instruction in defensive and ukemi techniques, particularly those that discourage the use of hands to prevent falls during throws, to reduce the risk of elbow injuries.

Results of endoprosthesis of the elbow joint in patients with tumors of forming it bones

Background. The use of both individual and modular oncological endoprostheses of the elbow joint is possible with primary and secondary (metastatic) tumor lesions of the bones forming it. The purpose of the study was to assess the effectiveness of restoring the function of the elbow joint and the upper limb and improving the quality of life of the patient after endoprosthesis of the elbow joint due to tumors of the bones forming it. ­Material and methods. The results of the treatment of 14 patients who underwent endoprosthesis of the elbow joint due to tumors of the bones forming it were evaluated. Endoprosthesis was performed in 9 (64.3 %) subjects with primary bone tumors and in 5 (35.7 %) patients with metastatic tumors. Reconstruction of the elbow joint was performed with individual oncological endoprostheses in 10 (71.4 %) subjects and modular oncological endoprostheses in 4 (28.6 %) ones. Reconstruction was primary in 12 (85.7 %) patients and secondary in 2 (14.3 %) ones. Results. Du­ring follow-up, 4 (28.6 %) patients died from the progression of the main disease with an ave­rage follow-up period of 24.8 ± 11.9 months, the other 10 (71.4 %) were alive, with an average follow-up period of 80.8 ± 10.3 months. In the early postoperative period, the following complications were observed: neuropathy of the ulnar nerve in 1 (7.1 %) patient. In the late postoperative period, 1 (7.1 %) patient had an infectious complication after 14 months. 1 (7.1 %) subject developed aseptic loose­ning of the humeral leg of the endoprosthesis 12 months after endoprosthesis. In 1 (7.1 %) subjects with a metastatic tumor, local recurrence of the tumor was observed 9 months after surgery. Mean MEPS and MSTS functional scores were 80 and 72 %, respectively. The patients’ quality of life (according to the EORTQ-QLQ-С30 questionnaire) increased from 40 points in the preoperative period to 84 points after elbow joint replacement. Conclusions. Endoprosthesis of the elbow joint in the schemes of complex and combined treatment of primary and metastatic tumors of the bones forming it helps to improve the quality of life of this contingent of patients.

Improving quantitative neuromuscular monitoring: an education initiative on stimulating electrode placement.

Quantitative neuromuscular monitoring reduces the incidence of residual neuromuscular block, but broad acceptance of monitoring has been elusive despite recommendations for quantitative monitoring for decades. Acceptance of quantitative monitoring may, in part, be related to the quality of the data from monitoring systems. This evaluation explored proper stimulating electrode positioning for electromyographic (EMG) monitoring, the impact of an educational intervention on electrode positioning and anesthesia provider (anesthesiologist, resident, anesthetist) confidence in the monitoring data from the device. In a single-center, observations of EMG electrode placement by anesthesia technicians, in 55 adult elective surgery patients were made by an independent observer. Separately, the anesthesia provider satisfaction with EMG derived data was recorded after reversal of neuromuscular block. An educational intervention then occurred on proper electrode positioning, including prior observations of electrode positioning, and prior anesthesia provider satisfaction with the EMG derived data. After the intervention, stimulating electrode position was observed with an additional 60 patients and anesthesia provider satisfaction with the data was again ascertained. The educational intervention significantly increased the proportion of ideal ulnar nerve groove electrode positioning from 74.5% to 95% (P < 0.003) and ideal wrist crease positioning (distal electrode within 2cm of crease) from 61.8% to 96.7% (P < 0.001). Anesthesia provider confidence with EMG derived information during anesthesia delivery, increased from 67 to 90% after the education (P = 0.005). There was a significant relationship between correct stimulating electrode placement and anesthesia provider confidence in the EMG derived data on neuromuscular block status. An educational intervention to improve EMG electrode positioning proved meaningful. It increased anesthesia provider confidence in the EMG derived data during anesthesia case management.

Ultrasound as a Complementary Tool to Electrodiagnostics in the Evaluation of Compressive Neuropathy of the Common Fibular Nerve

Background: Compressive neuropathy of the common fibular nerve (CFN) is increasingly recognized as an etiology for foot drop and falls. Electrodiagnostic (EDX) studies are widely used to evaluate this condition, but such tests are invasive and costly. As with carpal and cubital tunnel syndromes, there may be patients with characteristic symptoms of CFN compressive neuropathy but normal EDX studies in which ultrasound may aid in decision-making. Purpose: We sought to examine the association between ultrasound and nerve conduction studies (NCS) and electromyography (EMG) in the diagnosis of compressive neuropathy of the CFN. Methods: We performed a retrospective review identifying 104 patients who underwent CFN decompression from January 1, 2015, to June 30, 2023. Patients were included if they had both ultrasound and NCS/EMG prior to CFN decompression for compressive neuropathy and if they were older than 18 years at time of surgery. Patients were excluded if they had entrapment secondary to trauma, iatrogenic injury, or if they had had superficial fibular decompression alone without CFN decompression. After applying exclusion criteria, 17 patients remained in the cohort. Results: Mean ultrasound cross-sectional area and side-to-side (STS) ratios were significantly higher in those with abnormal compound muscle action potential (CMAP) amplitudes versus those with normal CMAP amplitudes. The probability of having an abnormal CMAP amplitude when STS ratio was abnormal was 18 times greater compared with those with normal STS ratio. With each unit increase in STS ratio, CMAP amplitude was reduced by 2.79 mV. Conclusions: This retrospective review found that ultrasound may provide complementary diagnostic information to EMG/NCS for compressive neuropathy of the CFN. Further study is needed to examine the relationship between ultrasound findings for CFN compressive neuropathy and results of surgical decompression.

Outcome of End to Side Nerve Modified Double Oberlin Procedure and End to End Dorsal Approach Spinal Accessory to Suprascapular Nerve in Partial Postganglionic BPI: A Case Report

Introduction: Brachial plexus injury (BPI) is a devastating peripheral nerve injury that mostly affecting young men, often due to motor vehicle accidents. BPIs can be classified into preganglionic and postganglionic lesions, with postganglionic injuries allowing potential nerve regeneration. The Oberlin method, aimed at reinnervating the biceps, and the Mackinnon technique, targeting both biceps and brachialis muscles, have shown promising outcomes in BPI management. Case report: A 45-year-old man presented with right hand weakness and occasional tingling in the upper arm and fingers two months after a motorcycle accident. Motor examination revealed muscle strength of 0/5 in the right trapezius, rhomboids, serratus anterior (positive winging scapula), pectoralis minor and major, latissimus dorsi, deltoid, biceps, and elbow flexion. Wrist and finger functions remained intact. Diagnosed with post-ganglionic BPI, the patient underwent two nerve transfer surgeries: the Mackinnon technique, transferring the spinal accessory nerve to the suprascapular nerve to reinnervate shoulder muscles, and the Double Oberlin procedure, transferring fascicles from the median and ulnar nerves to the musculocutaneous nerve for reinnervation of the biceps and brachialis muscles. Post-surgery, the patient engaged in an aggressive rehabilitation program focusing on strength, range of motion, and sensory re-education. Over nine months, the patient showed significant improvement in elbow flexion (MRC grade 3), wrist extension (MRC grade 5), hand grip strength (MRC grade 3) with improved sensation across the affected limb. He returned to work and daily activities with mild residual weakness and sensory deficits. Discussion: This case illustrates the effectiveness of the Mackinnon and Double Oberlin nerve transfer techniques in restoring function in a patient with total post-ganglionic BPI. The Mackinnon technique enabled shoulder muscle reinnervation, essential for abduction and stabilization, while the Double Oberlin procedure enhanced elbow flexion by reinnervating both the biceps and brachialis muscles. The combined surgical and intensive rehabilitation approach facilitated significant functional recovery. Conclusion: The successful application of the Double Oberlin and Mackinnon techniques in this case demonstrates their potential in managing total post-ganglionic BPI. Early surgical intervention and consistent rehabilitation are crucial for optimizing recovery outcomes. This case highlights the importance of a multidisciplinary approach in treating complex peripheral nerve injuries. Keywords: Double Oberlin, Mackinnon, Brachial Plexus Injury

Train-of-four ratio, counts and post tetanic counts with the Tetragraph electromyograph in comparison to mechanomyography.

Automated EMG devices to detect compound muscle action potentials from the adductor pollicis muscle in response to ulnar nerve stimulation, regardless of hand and thumb position, may serve as a better reference ("gold standard") for clinical assessment of neuromuscular function than traditional mechanomyography (MMG) systems that need custom design and validation in lab settings. This evaluation compared the TetraGraph EMG system against a validated MMG device to investigate the accuracy and repeatability of this quantitative EMG monitor for detecting onset, offset and deep neuromuscular block. Simultaneous muscle action potential recordings from the EMG neuromuscular monitor and muscle contractions from an in-house developed MMG monitor in response to ulnar nerve stimulation were obtained from patients having elective surgery requiring neuromuscular block. Train-of-four (TOF) ratios, TOF counts, and post-tetanic counts (PTCs) were recorded simultaneously from the same hand muscle and compared. In total, 685 pairs of simultaneous TOF ratios were evaluated. The mean difference (bias) of TOF ratios between devices was small (-2.1%). TOF counts from 285 data pairs were within a count of 2 or less 96% of the time. During deep block, PTC comparisons from 215 data pairs were within a count of 2 or less 95% of the time. These findings, along with prior EMG device evaluations, indicate that real-time EMG neuromuscular monitoring technology to detect muscle action potentials from the adductor pollicis in the clinical setting is closely aligned with the force of thumb contraction determined from MMG. The accuracy of quantitative EMG technology of the TetraGraph EMG system lends strong support for this monitor, along with other similarly validated EMG monitors, to become a clinical standard for all phases (onset, depth and reversal) of neuromuscular block in clinical practice.

Nerve ultrasound in amyotrophic lateral sclerosis: systematic review and meta-analysis

Background/ AimAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting upper and lower motor neurons, causing progressive atrophy of muscles, hypertonia, and paralysis. This study aimed to evaluate the current evidence and effectiveness of ultrasound in investigating nerve cross-sectional area (CSA) of peripheral nerves, vagus and cervical roots in those with ALS compared with healthy controls and to pool the CSA measurements.MethodsA systematic search was conducted on Cochrane, Clarivate Web of Science, PubMed, Scopus, and Embase for the mesh terms nerve, ultrasonography, and amyotrophic lateral sclerosis. A quality assessment was performed using the New-Ottawa scale. In addition, a double-arm meta-analysis using Review Manager 5 software version 5.4 was performed.ResultsFrom the seventeen studies included in this review, the overall mean difference showed that individuals with ALS had a significantly smaller CSA in comparison to healthy controls for median, ulnar, C6 root, and phrenic nerves. However, no significant difference in the CSA was found in radial, vagal, sural, and tibial nerves.DiscussionThis study confirmed results of some of the included studies regards the anatomic sites, where nerve atrophy in ALS could be detected to potentially support the diagnosis of ALS. However, we recommend further large, prospective studies to assess the diagnostic value of these anatomical sites for the diagnosis of ALS.ConclusionsOur findings confirmed specific anatomic sites to differentiate ALS patients from healthy controls through ultrasound. However, these findings cannot be used to confirm the ALS diagnosis, but rather assist in differentiating it from other diagnoses.Trial registrationRetrospectively registered on July 30th 2024 in PROSPERO (PROSPERO (york.ac.uk)) with ID574702.Graphical abstract

Clinical-applied anatomy of the carpal tunnel regarding mini-invasive carpal tunnel release.

Carpal tunnel release is a widely performed procedure. Despite a high success rate, iatrogenic neurovascular injuries can occur which lead to a painful and unsatisfying outcome. This study conducted a detailed examination of the anatomy of the carpal tunnel and the proximity of neurovascular structures that are particularly susceptible to injury, especially in the context of minimally invasive carpal tunnel release procedures. The anatomy of the carpal tunnel of 104 wrists of 52 body donors was examined. The precise anatomical location and the presence of variations were recorded for the median nerve, ulnar nerve, ulnar artery and Berrettini branch. The distance between the median nerve, the ulnar artery, the ulnar nerve, and the Berrettini branch was measured in a proximo-distal and radio-ulnar direction in relation to the distal ulnar end of the carpal tunnel. The authors identified four main dangerous anatomical situations. (1) A proximal separation of the Long-Finger/Ring-Finger branch of the median nerve together with a narrow safe-zone; (2) an ulnar take-off of the recurrent muscle branch of the median nerve with a close radio-ulnar distance to the distal ulnar end of carpal tunnel; (3) an ulnar arterial arch lying close to the transverse carpal ligament; and (4) a proximal Berrettini branch also lying close to the latter. All situations are illustrated by photographs. Additionally, the authors present a sonographic carpal tunnel assessment protocol in order to reduce the risk of injury of any neurovascular structure in the proximity of the carpal tunnel. Certain patients may inherently face an increased risk of neurovascular injuries during minimally invasive carpal tunnel releases due to their anatomical variations. Four potentially risky scenarios were clearly illustrated. Consequently, one may consider conducting a preoperative ultrasound assessment of neurovascular structures at risk, when endoscopic or ultrasound-guided tunnel release are planned. In high-risk patients, open surgery should be preferred. II.

Pain tolerance and the thresholds of human sensory and motor axons to single and repetitive bursts of kilohertz-frequency stimulation.

Transcutaneous electrical stimulation with repetitive bursts of a kilohertz carrier frequency is thought to be less painful than conventional pulsed currents by reducing the sensitivity of pain receptors. However, no purported benefit has been shown unequivocally. We compared the effects of carrier-frequency stimulation and conventional stimulation on pain tolerance and the thresholds for sensory and motor axons in twelve participants. The ulnar nerve was stimulated transcutaneously with a conventional single pulse and 5 and 10kHz carrier-frequency waveforms that had 5 and 10 pulses, respectively, when delivered in bursts of ∼1ms duration. Phase durations were adjusted across waveform types to match the total charge for a given current amplitude. Single bursts of stimulation were delivered from 1mA up until no longer tolerable. This was repeated with repetitive bursts of stimulation at 20Hz for 1s. Participants tolerated higher current amplitudes with both carrier-frequency waveforms than conventional stimulation, with repetitive bursts more painful than single bursts. However, compared to conventional stimulation, carrier-frequency waveforms required more current to produce sensory and motor-threshold responses and to obtain a maximal motor response (Mmax). When the current at pain tolerance was normalised to the current at Mmax, participants tolerated lower stimulus intensities with carrier-frequency waveforms than conventional stimulation. These findings indicate that there is little to no benefit in using carrier-frequency waveforms to minimise the discomfort from electrical stimulation as the increase in stimulus intensity at pain tolerance is more than offset by reduced effectiveness in the activation of sensory and motor axons. KEY POINTS: Transcutaneous electrical stimulation with repetitive bursts of a kilohertz carrier-frequency waveform is thought to be less painful than conventional pulsed currents. For ulnar nerve stimulation, when stimulus waveforms were matched for total phase charge, participants tolerated higher current amplitudes with carrier-frequency stimulation than conventional stimulation. However, compared to conventional stimulation, carrier-frequency waveforms required more current to produce a threshold response in both sensory and motor axons and to produce a maximal motor response (Mmax). When current at pain tolerance was normalised to current at Mmax, participants tolerated lower stimulus intensities with carrier-frequency waveforms than conventional stimulation. Carrier-frequency waveforms provide little to no benefit in minimising the discomfort from transcutaneous electrical stimulation as the increase in stimulus intensity at pain tolerance is more than offset by reduced effectiveness in activating sensory and motor axons.

Modified medial approach for the treatment of fractures of the lower third of the humeral shaft: An anatomical study

BackgroundThe anatomical study of the modified medial approach for addressing fractures of the distal third of the humeral shaft aimed to elucidate the benefits of this method in providing optimal exposure for surgical intervention. MethodsSixteen upper limb specimens from eight cadavers, obtained from the Anatomy Teaching Department of Fujian Medical University, were dissected. Three-dimensional anatomical structures were mapped onto a two-dimensional coordinate system. Key anatomical structures relevant to the modified medial approach, including the medial cutaneous nerve, musculocutaneous nerve, ulnar nerve, basilic vein, brachial artery, superior ulnar collateral artery, and inferior ulnar collateral artery, were documented in detail. ResultsThe average humeral shaft length measured (29.22 ± 2.78) cm, with its medial surface being flat and well-suited for plate fixation. The basilic vein, located superficially in the upper arm's first quadrant, measured (1.35 ± 0.35) cm from the most prominent point of the medial epicondyle of the humerus, with the deep fascia being penetrated at (12.41 ± 1.71) cm. The basilic vein serves as a key landmark for the modified medial approach. The nervi cutanei antebrachii medialis, running along the medial biceps humerus, closely accompanies the basilic vein, perforating the deep fascia above the medial epicondyle and extending anterior external and posterior medial branches. These branches are positioned (0.80 ± 0.17) cm and (0.45 ± 0.29) cm, respectively, from the basilic vein. Additionally, all nervi cutanei antebrachii medialis pass anteriorly to the basilic vein before continuing distally to the forearm. The ulnar nerve initially accompanies the basilic vein in the upper arm but diverges posteriorly without branching at (14.75 ± 1.74) cm, with the maximum separation from the basilic vein measuring (2.28 ± 0.59) cm. The brachial artery bifurcates into the superior and inferior ulnar collateral arteries along the humeral shaft. The superior collateral ulnar artery primarily supplies the ulnar nerve, positioned (14.14 ± 1.27) cm from the medial epicondyle, which ensures a sufficient blood supply for operative procedures. The musculocutaneous nerve and radial nerve branch are located in the lateral region of the brachial muscle, with minimal postoperative impact on muscle strength when splitting the brachial muscle by one-third. ConclusionsThe modified medial approach, as revealed by anatomical studies, focuses on the fracture site with a straight skin incision aligned between the most prominent point of the medial epicondyle and the midpoint of the axilla, positioned one transverse finger from the radial side. Using the basilic vein as a reference, major vessels and nerves remain undisturbed, ensuring a safe operative zone. This technique allows for significant exposure of both the anterior and external humeral shaft fracture site and the ulnar side butterfly fragment while minimizing tissue damage and facilitating rapid recovery. The approach offers notable clinical value due to its reduced invasiveness and accelerated postoperative rehabilitation.

The Effects of Photobiomodulation Therapy in Cubital Tunnel Syndrome, Clinical Trial.

Aim: We aimed to evaluate the effects of laser therapy together with rest splint and exercise on muscle strength, function, activities of daily living, and pain in individuals suffering from cubital tunnel syndrome (CuTS) by comparing it with placebo treatment. Materials and Methods: This prospective, single-blind, and randomized controlled study was conducted with 64 patients with CuTS in total. They were divided into two groups by randomization: Group 1 (n = 32) was provided with low-energy laser therapy + splint + exercise, and Group 2 (n = 32) was provided with low-energy sham laser therapy + splint + exercise. Patients in both groups received resting splints and nerve release exercises. Pretreatment and posttreatment (3rd week, 3rd month) evaluations were made with the Visual Analog Scale (VAS), the Quick Disability of Arm, Shoulder, and Hand Questionnaire, hand grip strength, fingertip grip strength, the Patient-Rated Ulnar Nerve Evaluation Scale (PRUNES), and Short Form-12. An electrophysiological evaluation was performed at baseline and at the 3rd month. Results: We observed significant improvements in both groups regarding pain, function, muscle strength, health profile, and quality of life in the early posttreatment (3rd week) stage and at the 3rd-month follow-up. When both groups were compared, a significant difference was determined between the VAS-Rest, VAS-Movement, PRUNES-Pain, PRUNES-Function, and PRUNES-Total parameters in the posttreatment (3rd week follow-ups), as well as PRUNES-Pain scores in the post-treatment (3rd month) stage, of the groups in favor of those in Group 1 (p < 0.05). Conclusion: The findings of our study have shown that in the treatment of CuTS, laser treatment is superior to placebo in the short term, but they have equivalent effects in the medium term. Further studies with large patient populations are needed to provide more diverse information about the therapeutic effectiveness of low-intensity laser therapy.

METHODS OF PERCUTANEOUSFIXATION OF FRAGMENTS IN SUPRACONDYLAR HUMERUS FRACTURES IN CHILDREN AND ADOLESCENTS

The aim of this study is to conduct a meta-analysis and evaluate the clinical efficacy and safety of crossed and lateral fixation of fragments in supracondylar humerus fractures in children and adolescents. Methods. A comprehensive literature search was conducted in the PubMed and EMBASE databases from 2015 to December 2023 using the following search terms: "supracondylar fractures of distal humerus in pediatric patients", "treatment", "methods of fixation", "pinning configuration", "biomechanical analysis of pin placement". According to the inclusion and exclusion criteria, the literature sources of anatomic-biomechanical and clinical studies related to the use of crossed and lateral fixation of fragments in the case of supracondylar fractures of the humerus in children and adolescents were selected and analyzed. The review was prepared in accordance with the recommendations of the "Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines." Results. A comparison of results from experimental studies investigating the degree of stabilization achieved in the crossed and lateral configurations of fixation structures reveals conflicting conclusions due to the heterogeneity of designs implemented. The principal limitation of lateral fixation is the increased risk of failure of fixation. The outcomes of clinical trials (Flynn criteria) demonstrate that both types of fracture fixation yield equivalent clinical outcomes. One disadvantage of crossed fixation is the risk of iatrogenic ulnar nerve damage, while another disadvantage is the increased complexity of the surgical technique. Conclusions. The results of anatomical and biomechanical studies indicate that cross-fixation provides more rigid fixation of fragments in supracondylar humerus fractures in children and adolescents. Nevertheless, clinical outcomes based on radiological and functional data (including Flynn's score) demonstrate no significant distinction between the two types of fixation configurations. However, they do indicate a notable risk of iatrogenic ulnar nerve damage in cross fixation, which justifies the necessity to utilise a mini-open technique in the medial fixation construct.

Radiological and biomechanical evaluation of the ulnar nerve after the percutaneous application of the medial K-wire in the extended position on supracondylar humerus fractures: Does the postoperative long arm splint position matter?

Our study aimed to evaluate and compare the changes in ulnar nerve tension and strain at different elbow positions radiologically and mechanically before and after applying the medial K-wire on the supracondylar humerus fracture cadaver model. We used ten fresh frozen cadaver upper extremity specimens to measure strain and tension on the ulnar nerve in 3 different elbow positions: elbow full extension, elbow flexion-forearm supination, and elbow flexion-forearm pronation. We employed Shear wave elastography (Siemens Acuson S3000 USG, 9L4 linear probe) and a microstrain gauge (Microstrain, Inc., Burlington) to obtain our measurements. Minimum, maximum and mean stress and strain values on the nerve and its surroundings were measured and compared statistically. The mean values of elbows with full extension are statistically lower than those in elbows with 90° flexion-forearm supination and those with 90° flexion-forearm pronation positions. Statistical evaluations were performed between all of the groups. Elbow 90° flexion-forearm pronation, both minimum and maximum and mean values were statistically higher in the group, including the specimens with Kirschner applied. The mean values in the elbow full extension and elbow 90° flexion-forearm supination positions were statistically similar in the specimens with and without the K-wire applied. Despite the numerous techniques described in the literature, there is no absolute technical method to prevent ulnar nerve damage. K-wire application to the medial epicondyle with the elbow in a slightly extended position is a technique that can be applied to reduce the risk of ulnar nerve paralysis. However, it has been reported that ulnar nerve damage can be observed in cases where a splint is placed in the 90° flexion position. We hypothesize that the position of the elbow joint in the postoperative period may contribute to ulnar nerve paralysis due to soft tissue tension and strain and as a result of changing the balance of the surrounding tissues. Our findings suggest that the long arm splint applied in elbow 90° flexion and forearm pronation position should not be preferred in the postoperative period. The maximum strain values obtained in the elbow full extension were lower, suggesting that it would be appropriate to stabilize the elbow in the extension position as much as possible postoperatively. Level of evidence: Level V.