Decompression and collagen wrapping of a fibrolipomatous hamartoma of the median nerve: a new approach for a rare and difficult problem

Fibrolipomatous hamartoma is a rare benign slow growing fibrofatty tumor of peripheral nerves of unknown etiology. Clinical presentation may mimic carpal tunnel syndrome when involving the median nerve. We present a case of FLH of the median nerve in a 59-year-old female treated with decompression and collagen nerve wrapping.

Non-invasive in vivo study of morphology and mechanical properties of the median nerve

The current literature studied the median nerve (MN) at specific locations during joint motions. As only a few particular parts of the nerve are depicted, the relevant information available is limited. This experiment investigated the morphological and biomechanical properties of the MN. The effects of the shoulder and wrist motions on MN were explored as well. Eight young healthy female individuals were tested with two-dimensional ultrasound and shear wave elastography (SWE). The morphological and biomechanical properties were examined in limb position 1, with the wrist at the neutral position, the elbow extended at 180°, and the shoulder abducted at 60°. In addition, the experiment assessed the differences among the wrist, forearm, elbow, and upper arm with Friedman's test and Bonferroni post hoc analysis. Two groups of limb positions were designed to explore the effects of shoulder movements (shoulder abducted at 90° and 120°) and wrist movements (wrist extended at 45° and flexed at 45°) on the thickness and Young's modulus. Differences among the distributions of five limb positions were tested as well. The ICC3, 1 values for thickness and Young's modulus were 0.976 and 0.996, respectively. There were differences among the MN thicknesses of four arm locations in limb position 1, while Young's modulus was higher at the elbow and wrist than at the forearm and upper arm. Compared to limb position 1, only limb position 4 had an effect on MN thickness at the wrist. Both shoulder and wrist motions affected MN Young's modulus, and the stiffness variations at typical locations all showed a downward trend proximally in all. The distributions of MN thickness and Young's modulus showed fold line patterns but differed at the wrist and the pronator teres. The MN in the wrist is more susceptible to limb positions, and Young's modulus is sensitive to nerve changes and is more promising for the early diagnosis of neuropathy.

Improved visualization of median, ulnar nerves, and small branches in the wrist and palm using contrast-enhanced magnetic resonance neurography

Background

Magnetic resonance imaging of peripheral nerves in the wrist and palm is challenging due to the small size, tortuous course, complex surrounding tissues, and accompanying blood vessels. The occurrence of carpal palmar lesions leads to edema, swelling, and mass effect, which may further interfere with the display and identification of nerves.

Objective

To evaluate whether contrast-enhanced magnetic resonance neurography (ceMRN) improves the visualization of the morphology and pathology of the median, ulnar nerves, and their small branches in the wrist and palm.

Design

An observational study.

Methods

In total 57 subjects, including 36 volunteers and 21 patients with carpal palmar lesions, were enrolled and underwent ceMRN and non-contrast MRN (ncMRN) examination at 3.0 Tesla. The degree of vascular suppression, nerve visualization, diagnostic confidence, and lesion conspicuity was qualitatively assessed by two radiologists. Kappa statistics were obtained for inter-reader agreement. The signal-to-noise ratio, contrast ratio (CR), and contrast-to-noise ratio (CNR) of the median nerve were measured. The subjective ratings and quantitative measurements were compared between ncMRN and ceMRN.

Results

The inter-reader agreement was excellent (k > 0.8) for all qualitative assessments and visualization assessment of each nerve segment. Compared with ncMRN, ceMRN significantly improved vascular suppression in volunteers and patients (both p < 0.001). The ceMRN significantly enhanced nerve visualization of each segment (all p < 0.05) and diagnostic confidence in volunteers and patients (both p < 0.05). The ceMRN improved lesion conspicuity (p = 0.003) in patients. Quantitatively, ceMRN had significantly higher CRs of nerve versus subcutaneous fat, bone marrow, and vessels and CNR of nerve versus vessel than ncMRN (all p < 0.05).

Conclusion

The ceMRN significantly improves the visualization of peripheral nerves and pathology in the wrist and palm by robustly suppressing the signals of fat, bone marrow, and especially vessels in volunteers and patients.

Median Nerve Shear Wave Elastography is Associated With the Neurophysiological Severity of Carpal Tunnel Syndrome

OBJECTIVES

This study examines the associations between the median nerve (MN) shear wave elastography (SWE), the MN cross-sectional area (CSA), patient's symptoms, and the neurophysiological severity of carpal tunnel syndrome (CTS). The most appropriate site to perform SWE was also tested.

METHODS

This prospective study comprised 86 wrists of 47 consecutive patients who volunteered for MN ultrasound after an electrodiagnostic study. The neurophysiological severity of CTS was assessed according to the results of a nerve conduction study (NCS). The MN CSA was measured at the carpal tunnel inlet (wCSA) and the forearm (fCSA). SWE was performed on the MN in a longitudinal orientation at the wrist crease (wSWE), at the forearm (fSWE), and within the carpal tunnel (tSWE).

RESULTS

The wCSA and wSWE correlated positively with the neurophysiological severity of CTS (r = .619, P < .001; r = .582, P < .001, respectively). The optimal cut-off values to discriminate the groups with normal NCS and with findings indicating CTS were 10.5 mm2 for the wCSA and 4.12 m/s for the wSWE. With these cut-off values, wCSA had a sensitivity of 80% and specificity of 87% and wSWE a sensitivity of 88% and specificity of 76%. Neither tSWE nor fSWE correlated with the neurophysiological severity of CTS or differed between NCS negative and positive groups (P = .429, P = .736, respectively).

CONCLUSION

Shear wave velocity in the MN at the carpal tunnel inlet increases in CTS and correlates to the neurophysiological CTS severity equivalently to CSA measured at the same site.

Capitate Proximal Fragment Migration Compressing the Median Nerve in Scaphocapitate Fracture: A Case Report

BACKGROUND Scaphocapitate syndrome is a rare clinical entity consisting of a combined scaphoid and capitate fracture along with a 90- or 180-degrees rotation of the proximal capitate fragment. The syndrome is scarcely described in the literature, with proximal migration of the capitate fragment being reported only by Mudgal et al in 1995. Concurrent compression of the median nerve is a highly unfortunate event, suggesting a unique case presented here. CASE REPORT We present a unique case of scaphocapitate fracture-dislocation in a 25-year-old man with volar dislocation of the capitate's fragment deep to the median nerve. X-rays and CT scan were performed and the patient was treated few hours after the injury by a hand specialist, in order to prevent median neuropathy and avascular necrosis of the fragment. Open reduction and internal fixation utilizing a Herbert screw for the scaphoid fracture and 3 additional K-wires was performed. Immediately post-operatively, the acute neurological symptoms had subsided and good reduction was acquired radiologically. One year post-operatively the patient had regained good hand and wrist functionality, with no extension or flexion ROM deficits. CONCLUSIONS Immediate intervention in a specialized center with reduction and fixation utilizing a Herbert screw and K-wires showed favorable 1-year results in our case of scaphocapitate syndrome. The impending complications of median neuropathy and capitate avascular necrosis were avoided despite the high-risk injury pattern.

Evaluating the Need for Simultaneous Carpal Tunnel Release With Forearm Fasciotomy

PURPOSE

The need to include simultaneous carpal tunnel release (sCTR) with forearm fasciotomy for acute compartment syndrome (ACS) or after vascular repair is unclear. We hypothesized that sCTR is more common when: 1) fasciotomies are performed by orthopedic or plastic surgeons, rather than general or vascular surgeons; 2) ACS occurred because of crush, blunt trauma, or fractures rather than vascular/reperfusion injuries; 3) elevated compartment pressures were documented. We also sought to determine the incidence of delayed CTR when not performed simultaneously.

METHODS

Retrospective chart review identified patients who underwent forearm fasciotomy for ACS or vascular injury over a period of 10 years. Patient demographics, mechanism of ACS or indication for fasciotomy, surgeon subspecialty, compartment pressure measurements, inclusion of sCTR, complications, reoperations, and timing and method of definitive closure were analyzed. Logistic regression modeling was used to analyze predictors associated with delayed CTR.

RESULTS

Fasciotomies were performed in 166 patients by orthopedic (63%), plastic (28%), and general/vascular (9%) surgeons. Orthopedic and plastic surgeons more frequently performed sCTR (67% and 63%, respectively). A total of 107 (65%) patients had sCTR. Fasciotomies for vascular/reperfusion injury were more likely to include sCTR (44%) compared with other mechanisms. If not performed simultaneously, 11 (19%) required delayed CTR at a median of 42 days. ACS secondary to fracture had the highest rate of delayed CTR (35%), and the necessity of late CTR for fractures was not supported by the logistic regression model. Residual hand paresthesias were less frequent in the sCTR group (6.5% vs 20%). Overall complication rates were similar in both groups (63% sCTR vs 70% without sCTR).

CONCLUSION

When sCTR is excluded during forearm fasciotomy, 19% of patients required delayed CTR. This rate was higher (35%) when ACS was associated with fractures. Simultaneous CTR with forearm fasciotomy may decrease the incidence of residual hand paresthesias and the need for a delayed CTR.

LEVEL OF EVIDENCE

Prognosis IV.

A narrative review of pulsed radiofrequency for the treatment of carpal tunnel syndrome

OBJECTIVE

Carpal tunnel syndrome (CTS), which is the most common peripheral nerve entrapment syndrome, can commonly persist despite conservative treatment modalities such as wrist splinting or medications. Pulsed radiofrequency represents a minimally invasive pain intervention technique to alleviate pain. The literature was reviewed to establish the effectiveness of PRF therapy for CTS.

STUDY DESIGN

This is a narrative review of relevant articles on the effectiveness of PRF for CTS.

METHOD

Four databases, MEDLINE, Cochrane Central Register of Controlled Trials, Embase, OVID Emcare, and Web of Science, were systematically searched. 804 records were screened, and the reference lists of eligible articles were examined. For this review, eight extracted studies were narratively explored.

RESULTS

One case report, three retrospective cohorts, one observational prospective study, and three randomized-controlled trials were included. PRF likely provides both an analgesic and functional benefit in patients with mild to severe CTS, and it also shows benefit as an adjunct to carpal tunnel release surgery. Long-term data is limited. It also appears likely that steroid injection may represent a comparable treatment modality to PRF, and there have been positive results when these modalities are used together. Notably, all studies differed in their methodology, making direct comparisons between studies challenging.

CONCLUSIONS

The evidence for PRF in the treatment of CTS, across the range of spectrum of severity or peri-operative to CTS surgery, appears favorable and avoids known side effects of steroid injections. Potential mechanisms for PRF and future directions for research are explored.

Fibrolipomatous Hamartoma Over the Left Forearm and Palm

Introduction

Fibrolipomatous hamartomas are rare congenital benign tumors that can affect the nerves. The symptoms arise due to compression and may require surgical excision.

Case Report

A man in his mid-20s suffered swelling over the volar aspect of the left forearm and hand for 4 months. He was symptomatic. A soft, non-tender swelling of size 6 × 4 cm was present over the flexor aspect of the left forearm and palm, with features suggestive of median nerve compression. Magnetic resonance imaging and electromyography were performed. Decompression of the carpal tunnel was performed with debulking of fibrofatty elements and fine dissection of the neural elements.

Conclusion

This case report demonstrates a rare fibrolipomatous hamartoma encompassing the median nerve, which required surgical excision.

Safety and Efficacy of Ultrasound-Guided Perineural Hydrodissection as a Minimally Invasive Treatment in Carpal Tunnel Syndrome: A Systematic Review

Ultrasound-guided perineural hydrodissection (HD) is a novel technique that has been found to be effective in providing mechanical release of perineural adhesions and decompression of the nerve, reducing inflammation and edema and restoring its physiological function. It has a significant impact on chronic neuropathic pain (20 ± 4 weeks with VAS < 5 or VAS diminished by 2 points after the procedure). Carpal tunnel syndrome (CTS) is a common entrapment mononeuropathy, and its distribution is typically innervated by the median nerve. Patients with mild or moderate CTS may benefit from nonsurgical treatments or conservative therapies. This review was conducted following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement guidelines. Four investigators assessed each title, abstract, and full-text article for eligibility, with disagreements being resolved by consensus with two experienced investigators. The qualitative assessment of the studies was carried out using the modified Oxford quality scoring system, also known as the modified Jadad score. Furthermore, risk of possible biases was assessed using the Cochrane collaboration tool. The results of this review suggest that US-guided HD is an innovative, effective, well-tolerated, and safe technique (11 out of 923 patients had collateral or side effects after the procedure). However, further studies comparing all drugs and with a larger sample population are required to determine the most effective substance.

Intraosseous Nontraumatic Median Nerve Entrapment at the Elbow: A Case Report

Intraosseous median nerve entrapment at the level of the elbow can occur after a traumatic event such as fracture and/or dislocation of the elbow. It is considered a rare and severe entity. We present a rare case of nontraumatic median nerve entrapment inside the distal humerus. No article about atraumatic intraosseous entrapment was encountered in literature.

Postoperative Functional Analysis of Double Crush Versus Single Peripheral Nerve Decompression: A Retrospective Study

BACKGROUND

Double crush (DC) syndrome patients presenting with C6-7 radiculopathy and median nerve compression in the carpal tunnel report greater nerve irritability and weakness postdecompression than isolated peripheral nerve decompression. We hypothesize that patient-reported outcome is inferior following release at both cervical spine and wrist versus a single site of decompression.

METHODS

Patients that underwent either anterior cervical decompression and fusion (ACDF) for C6-C7 radiculopathy, carpal tunnel release (CTR), or both within 5 years (DC) were identified. A total of 477 patients were analyzed (157 DC, 203 CTR, and 117 ACDF). Post-operative outcome Disabilities of the Arm, Shoulder, and Hand (QuickDASH), Neck Disability Index, and visual analog scale (VAS) scores were collected at an average of 2 years postoperatively.

RESULTS

QuickDASH scores were higher in the DC group versus CTR group (36 vs 22, P < .0002). Postoperative disability in the ACDF group was significantly higher than the DC group (50 vs 36, P < .017). There were no differences between ACDF and DC groups in arm pain intensity, but the CTR group demonstrated significantly greater arm pain intensity than the DC group (5.7 vs 3.6, 10-point scale, P < .01).

CONCLUSIONS

Patients undergoing ACDF and CTR have greater postoperative disability than those undergoing CTR alone, but less postoperative functional disability and pain than ACDF alone, indicating cervical radiculopathy may contribute a greater proportion of long-term disability postoperatively. Additionally, CTR had greater postoperative arm pain than DC patients, potentially indicating high rates of undiagnosed cervical radiculopathy or other sources of arm pain in these patients.

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.

Nerve function restoration following targeted muscle reinnervation after varying delayed periods

Targeted muscle reinnervation has been proposed for reconstruction of neuromuscular function in amputees. However, it is unknown whether performing delayed targeted muscle reinnervation after nerve injury will affect restoration of function. In this rat nerve injury study, the median and musculocutaneous nerves of the forelimb were transected. The proximal median nerve stump was sutured to the distal musculocutaneous nerve stump immediately and 2 and 4 weeks after surgery to reinnervate the biceps brachii. After targeted muscle reinnervation, intramuscular myoelectric signals from the biceps brachii were recorded. Signal amplitude gradually increased with time. Biceps brachii myoelectric signals and muscle fiber morphology and grooming behavior did not significantly differ among rats subjected to delayed target muscle innervation for different periods. Targeted muscle reinnervation delayed for 4 weeks can acquire the same nerve function restoration effect as that of immediate reinnervation.

Median Nerves' Electrical Activation Reduces Ipsilateral Brachial Arteries' Blood Flow and Diameter

Purpose

Our main objective in this study was to determine whether there is a difference between ipsilateral and contralateral brachial arteries' flow parameters in response to median nerves' electrical activation.

Material and Methods

The study was conducted in healthy and active subjects. The arterial diameter and flow were measured using the probe from the brachial artery. Then, the median nerve was stimulated for 5 seconds via the bipolar stimulus electrode. Arterial diameter and flow were measured once more with the Doppler transducer, which kept going to monitor continuously just after the fifth stimulus. After a week, the same subjects are invited for the purpose of measuring the contralateral brachial arteries' vasomotor response to the same stimulus.

Results

Before electrical stimulation, the median flow rate was 72.15 ml/min; after stimulation, the median flow rate was 39.20 ml/min. The drop in flow after stimulation was statistically significant (P < 0.001). While the median value of brachial artery vessel diameter before median nerve stimulation in the entire study group was 3.50 mm, the median value of vessel diameter after stimulation was 2.90 mm. After stimulation, the median nerve diameter narrowed statistically significantly (P < 0.001). As for the contralateral brachial in response to the right median nerves' activation, no significant flow or diameter change was found (P = 0.600, P = 0.495, respectively).

Conclusion

We discovered that electrical stimulation of the median nerve caused significant changes in ipsilateral brachial artery blood flow and diameter in healthy volunteers. The same stimulation does not result in flow parameter changes in the contralateral brachial artery.

Base of the Third Metacarpal as a Palpable and Reliable Landmark for Identifying the Median Nerve's Thenar Branch

PURPOSE

The objective of this study was to investigate whether the base of the third metacarpal can predict the location of the thenar branch (TB) of the median nerve and the accuracy of palpating the base of the third metacarpal.

METHODS

In 15 patients with ulnar nerve lesions around the elbow, we transferred the opponens motor branch to repair the deep terminal division of the ulnar nerve (DTDUN). Before surgery, we located the TB by palpating the base of the third metacarpal volarly. During surgery, we placed three needles at the following places: one at the entrance of the TB into the abductor pollicis brevis, another at the point where the TB contacted the thenar muscles, and third at the DTDUN's trajectory over the third metacarpal. We obtained fluoroscopic images and measured distances between the needles and structures with image software. We also examined the relationship between the TB, DTDUN, and the volar tubercle of the base of the third metacarpal in cadaver hands. Finally, we invited 22 surgeons to palpate the base of the third metacarpal on volunteer hands and verified their accuracy using fluoroscopy.

RESULTS

During surgery, after dissection and palpation of the TB, under fluoroscopy, we confirmed that the palpable bone prominence was the base of the third metacarpal. In cadaver dissections, we observed the TB crossing the volar tubercle of the base of the third metacarpal superficially from proximal to distal and from ulnar to radial. The DTDUN was, on average, 14 mm distal to the base of the third metacarpal distal limit. In total, 19 of the 22 surgeons correctly identified the base of the third metacarpal and consequently the trajectory of the TB.

CONCLUSIONS

The palpable base of the third metacarpal can be used to determine the trajectory of both the TB and DTDUN.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

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

PURPOSE

Nerves that are functionally injured but appear macroscopically intact pose the biggest clinical dilemma. Second Harmonic Generation (SHG) Microscopy may provide a real-time assessment of nerve damage, with the ultimate goal of allowing surgeons to accurately quantify the degree of nerve damage present. The aim of this study was to demonstrate the utility of SHG microscopy to detect nerve damage in vivo in an animal model.

METHODS

Ten Sprague-Dawley rats were anesthetized and prepared for surgery. After surgical exposure and using a custom-made stretch applicator, the right median nerves were stretched by 20%, corresponding to a high strain injury, and held for 5 minutes. The left median nerve served as a sham control (SC), only being placed in the applicator for 5 minutes with no stretch. A nerve stimulator was used to assess the amount of stimulation required to induce a flicker and contraction of the paw. Nerves were then imaged using a multiphoton laser scanning microscope.

RESULTS

Immediately after injury (day 0), SHG images of SC median nerves exhibited parallel collagen fibers with linear, organized alignment. In comparison with SC nerves, high strain nerves demonstrated artifacts indicative of nerve damage consisting of wavy, undulating fibers with crossing fibers and tears, as well as a decrease in the linear organization, which correlated with an increase in the mean stimulation required to induce a flicker and contraction of the paw.

CONCLUSIONS

Second Harmonic Generation microscopy may provide the ability to detect an acute neural stretch injury in the rat median nerve. Epineurial collagen disorganization correlated with the stimulation required for nerve function.

CLINICAL RELEVANCE

In the future, SHG may provide the ability to visualize nerve damage intraoperatively, allowing for better clinical decision-making. However, this is currently a research tool and requires further validation before translating to the clinical setting.

Long latency reflexes of the median nerves in healthy adults

INTRODUCTION/AIMS

Long latency reflexes (LLRs) are late responses in nerve conduction studies seen after peripheral nerve stimulation during submaximal muscle contraction. They follow a short latency reflex, also known as the H reflex, and are thought to involve transcortical pathways, providing a measure of proximal nerve and central conduction. For this reason, they have been evaluated in several central nervous system diseases, but reference values are not widely published and are mostly based on old studies with very small numbers of participants. Therefore, in this work we aim to provide comprehensive reference values for LLR testing.

METHODS

LLRs were tested in a cohort of 100 healthy participants, testing the median nerve bilaterally.

RESULTS

Mean latencies for short latency reflex (SLR), LLR1, LLR2, and LLR3 were 27.00, 38.50, 47.60, and 67.34 milliseconds, respectively. The allowable side-to-side difference was approximately 3 to 4 milliseconds. No significant sex-related differences were seen. Height correlated moderately with the SLR latency, but only weakly with LLR1, LLR2, and LLR3.

DISCUSSION

This work provides normal LLR values for comparison with future studies in disease. The technique used may allow for improved evaluation of central nervous system or proximal peripheral nerve disorders.

The Cutaneous Branches of the Median and Ulnar Nerves in the Palm

PURPOSE

The dermatomal distributions of the ulnar and median nerves on the palmar skin of the hand have been studied thoroughly. However, the anatomic course of the median and ulnar cutaneous nerve branches and how they supply the skin of the palm is not well understood.

METHODS

The cutaneous branches of the median and ulnar nerves were dissected bilaterally in 9 fresh cadavers injected arterially with green latex.

RESULTS

We observed 3 groups of cutaneous nerve branches in the palm of the hand: a proximal row group consisting of long branches that originated proximal to the superficial palmar arch and reached the distal palm, first web space, or hypothenar region; a distal row group consisting of branches originating between the superficial palmar arch and the transverse fibers of the palmar aponeurosis (these nerves had a longitudinal trajectory and were shorter than the branches originating proximal to the palmar arch); and a metacarpophalangeal group, composed of short perpendicular branches originating on the palmar surface of the proper palmar digital nerves at the web space. The radial and ulnar borders of the hand distal to the palmar arch were innervated by short transverse branches arising from the proper digital nerves of the index and little finger. Nerve branches did not perforate the palmar aponeurosis in 16 of 18 cases.

CONCLUSIONS

The palm of the hand was consistently innervated by 20-35 mm long cutaneous branches originating proximal to the palmar arch and shorter branches originating distal to the palmar arch. These distal branches were either perpendicular or parallel to the proper palmar digital nerves.

CLINICAL RELEVANCE

Transfer of long proximal row branches may present an opportunity to restore sensibility in nerve injuries.

The Potential of Ultrasound Radiomics in Carpal Tunnel Syndrome Diagnosis: A Systematic Review and Meta-Analysis

Background: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy for which ultrasound imaging has recently emerged as a valuable diagnostic tool. This meta-analysis aims to investigate the role of ultrasound radiomics in the diagnosis of CTS and compare it with other diagnostic approaches. Methods: We conducted a comprehensive search of electronic databases from inception to September 2023. The included studies were assessed for quality using the Quality Assessment Tool for Diagnostic Accuracy Studies. The primary outcome was the diagnostic performance of ultrasound radiomics compared to radiologist evaluation for diagnosing CTS. Results: Our meta-analysis included five observational studies comprising 840 participants. In the context of radiologist evaluation, the combined statistics for sensitivity, specificity, and diagnostic odds ratio were 0.78 (95% confidence interval (CI), 0.71 to 0.83), 0.72 (95% CI, 0.59 to 0.81), and 9 (95% CI, 5 to 15), respectively. In contrast, the ultrasound radiomics training mode yielded a combined sensitivity of 0.88 (95% CI, 0.85 to 0.91), a specificity of 0.88 (95% CI, 0.84 to 0.92), and a diagnostic odds ratio of 58 (95% CI, 38 to 87). Similarly, the ultrasound radiomics testing mode demonstrated an aggregated sensitivity of 0.85 (95% CI, 0.78 to 0.89), a specificity of 0.80 (95% CI, 0.73 to 0.85), and a diagnostic odds ratio of 22 (95% CI, 12 to 41). Conclusions: In contrast to assessments by radiologists, ultrasound radiomics exhibited superior diagnostic performance in detecting CTS. Furthermore, there was minimal variability in the diagnostic accuracy between the training and testing sets of ultrasound radiomics, highlighting its potential as a robust diagnostic tool in CTS.

Deep Radiomics Features of Median Nerves for Automated Diagnosis of Carpal Tunnel Syndrome With Ultrasound Images: A Multi-Center Study

OBJECTIVES

Ultrasound is widely used in diagnosing carpal tunnel syndrome (CTS). However, the limitations of ultrasound in CTS detection are the lack of objective measures in the detection of nerve abnormality and the operator-dependent nature of ultrasound imaging. Therefore, in this study, we developed and proposed externally validated artificial intelligence (AI) models based on deep-radiomics features.

METHODS

We have used 416 median nerves from 2 countries (Iran and Colombia) for the development (112 entrapped and 112 normal nerves from Iran) and validation (26 entrapped and 26 normal nerves from Iran, and 70 entrapped and 70 normal nerves from Columbia) of our models. Ultrasound images were fed to the SqueezNet architecture to extract deep-radiomics features. Then a ReliefF method was used to select the clinically significant features. The selected deep-radiomics features were fed to 9 common machine-learning algorithms to choose the best-performing classifier. The 2 best-performing AI models were then externally validated.

RESULTS

Our developed model achieved an area under the receiver operating characteristic (ROC) curve (AUC) of 0.910 (88.46% sensitivity, 88.46% specificity) and 0.908 (84.62% sensitivity, 88.46% specificity) with support vector machine and stochastic gradient descent (SGD), respectively using the internal validation dataset. Furthermore, both models consistently performed well in the external validation dataset, and achieved an AUC of 0.890 (85.71% sensitivity, 82.86% specificity) and 0.890 (84.29% sensitivity and 82.86% specificity), with SVM and SGD models, respectively.

CONCLUSION

Our proposed AI models fed with deep-radiomics features performed consistently with internal and external datasets. This justifies that our proposed system can be employed for clinical use in hospitals and polyclinics.

Median nerve schwannoma with a diagnostic delay of 8 years: a case report

Introduction

Schwannomas are benign tumors of the peripheral nerve sheath, and the median nerve is the most commonly involved nerve. These benign tumors of the peripheral nerve sheath are very rare; they are clinically and radiologically similar to most other benign swellings of the hand; thus, they are often misdiagnosed.

Case Presentation

A 41-year-old lady presented with an 8-year-long history of swelling over the distal forearm. The tumor measured 3.5×3.5×3.5 mm and was located over the flexor aspect of the distal part of her right forearm. Schwannoma was suspected from the clinical presentation and imaging, but the final diagnosis was established only after the surgery and histopathological analysis. At the follow-up after 1 year, the patient is doing well and her symptoms have not recurred.

Conclusion

Imaging characteristics of schwannoma can be misinterpreted as some other condition, making the preoperative diagnosis very difficult and important. Thus, clinicians should be aware of such swellings, especially those that have been unnoticed or misdiagnosed, and provide optimal diagnoses to confer good outcomes.

Lacertus Fibrosus Syndrome: A Case Report

Lacertus fibrosus syndrome is described as compression of the median nerve, which takes place beneath a layer of ligamentous tissue (lacertus fibrosus, also known as bicipital aponeurosis) slightly beyond the elbow joint. Both sexes can develop lacertus fibrosus syndrome, most often after the age of 35. The possible risk factors are repetition of movements, overwork, and manual work while the forearm is pronated. Lacertus fibrosus syndrome presents a distinct diagnostic challenge because it is a somewhat unknown and non-documented disease. Its symptoms are often mistaken for those of carpal tunnel syndrome, which complicates the differential diagnosis and management of the patient. All patients who report tingling, numbness, loss of strength, muscle loss, manual endurance, or dexterity should be investigated and tested for both carpal tunnel syndrome and lacertus syndrome. Here, a case of a 43-year-old woman is discussed, who presented with chief complaints of pain and tingling sensation in the left upper limb, which was associated with loss of thumb pinch grip. The pain was aggravated with elbow extension and relieved with rest. The patient underwent left elbow median nerve decompression and was discharged in steady condition. This case report highlights the accurate clinical presentation and surgical intervention for the syndrome, for which the outcome turned out to be satisfying.

Case report: Giant atypical granular cell tumor of the median nerve

Granular cell tumors are extremely uncommon soft tissue neoplasms that mostly occur in the head and neck regions. Granular cell tumors are generally benign, asymptomatic, and rarely involve the median nerve. Due to the lack of awareness about granular cell tumors, they are easily misdiagnosed and mistreated in primary hospitals. Here, we report a giant atypical granular cell tumor located on the median nerve, approximately 12 cm in size, with unusual symptoms of median nerve damage. Magnetic resonance imaging revealed a fusiform mass that was hyperintense on T2-weighted images and iso-hypointense on T1-weighted images. The mass was subsequently biopsied and found to be a granular cell tumor. The tumor was resected, and a pathological examination was performed. Pathological examination revealed necrotic foci, abundant eosinophilic granules, pustular ovoid bodies, and multiple mitoses. Immunohistochemical staining revealed that the tumor cells were positive for S-100, CD68, SMA, SOX-10, Calretinin, and TFE3. The integrated diagnosis was an atypical granular cell tumor. To the best of our knowledge, this is the first report of an atypical granular cell tumor involving the median nerve. Furthermore, we comprehensively reviewed the existing literature to provide a concise summary of the diagnostic criteria, imaging findings, and pathological features of granular cell tumors. Given the high recurrence and metastasis rates of this disease, granular cell tumors of the median nerve should be considered when a patient presents with symptoms of median nerve impairment. The diagnosis of atypical granular cell tumors relies on pathological examination. In addition, extensive resection and long-term follow-up are necessary to improve prognosis.

Progression From Steroid Injection to Surgery in Carpal Tunnel Syndrome Patients With Concurrent Ulnar Nerve Compression: A Retrospective Analysis

BACKGROUND

Steroid injections are a common treatment option in the management of carpal tunnel syndrome (CTS). This study assesses various prognostic factors for progression to carpal tunnel release (CTR) after a first-time steroid injection for CTS with specific focus on concomitant ulnar nerve compression (UNC).

METHODS

This is a retrospective study of 426 hands with CTS treated with a first-time steroid injection in the Long Island region of New York. The main predictor variable was UNC measured in two analytical models of positive UNC and location of UNC (wrist or elbow). Multivariate logistic regression analyses adjusted for demographic, medical, and CTS-related variables for 2 study outcomes occurring within 1 year: (1) CTR; and (2) steroid reinjection.

RESULTS

Overall progression to CTR within 1 year of steroid injection was 23.0%. Ulnar nerve compression was present in 16.7% of patients and was significantly associated with increased odds for CTR but not with steroid reinjection. These results were further localized to be specific for UNC at the elbow. A moderate or severe result on electrodiagnostic studies was associated with increased odds for CTR. Increased age was associated with slightly increased odds of steroid reinjection while a history of distal radius fracture was associated with decreased odds of steroid reinjection.

CONCLUSIONS

Carpal tunnel syndrome patients with UNC may benefit from earlier definitive treatment with CTR rather than attempting steroid injections, as they are more likely to seek reintervention within 1 year of their initial injection.

10-Year Clinical Follow-Up after Decompression of Lipofibromatous Hamartoma of the Median Nerve in a 3-Year-Old Patient: Case Report and Review of the Literature

Lipofibromatous hamartoma, first reported in 1953, is a rare, slowly progressive soft tissue tumor, the characteristics of which include the enlargement of the affected nerve via the epineurial and perineurial proliferation of adipose and fibrous tissues. Out of 200 previously reported cases of lipofibromatous hamartoma of the median nerve, there have been approximately 25 pediatric cases under the age of 18. Herein, we report a case of lipofibromatous hamatoma of the median nerve in a 3-year-old female patient who was surgically decompressed via carpal tunnel release and epineurolysis. The patient was followed-up on an outpatient clinic basis annually with sonographic evaluations, and the postoperative 10th-year follow-up did not show recurrence or any deficits in motor and sensory functions.

Sonographic reference values for median nerve cross-sectional area: A meta-analysis of data from healthy individuals

Objective

Establish median nerve CSA reference values and identify patient-level factors impacting diagnostic thresholds.

Methods

Studies were identified through a robust search of multiple databases, and quality assessment was conducted using a modified version of the National Institute of Health Study Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. A meta-analysis was performed to identify normative values stratified by anatomic location. A meta-regression was conducted to examine heterogeneity effects of age, sex, and laterality.

Results

The meta-analysis included 73 studies; 41 (56.2%) were high quality. The median nerve CSA [95% CI] was 6.46mm2 [6.09-6.84], 8.68mm2 [8.22-9.13], and 8.60mm2 [8.23-8.97] at the proximal forearm, the carpal tunnel inlet, and the proximal carpal tunnel, respectively. Age was positively associated with CSA at the level of proximal carpal tunnel (β=0.03mm2, p=0.047). Men (9.42mm2, [8.06-10.78]) had statistically larger proximal tunnel CSA (p = 0.03) as compared to women (7.71mm2, [7.01-8.42]). No difference was noted in laterality.

Conclusion

A reference value for median nerve CSA in the carpal tunnel is 8.60mm2. Adjustments may be required in pediatrics or older adults. The diagnostic threshold of 10.0mm2 for male patients should be cautiously applied as the upper limit of normative averages surpasses this threshold.

A rare case of an intraneural ganglion cyst of the median nerve

Aim of the study

Intraneural ganglion cysts are a relatively uncommon type of ganglion cyst that can affect peripheral nerves. They are particularly rare in the upper limb, and even more so in the median nerve, with the vast majority of them occurring in the peroneal nerves. This paper aims to make the reader aware of this relatively uncommon condition.

Case description

We report a case of a 41-year-old male who presented with a gradually progressing mass on the volar aspect of the wrist extending to the index finger. The nonspecific presentation as well as the rarity of the condition may make diagnosis challenging. The patient was referred for surgical management under a specialist peripheral nerve hand surgeon.

Conclusions

Ultrasound and magnetic resonance imaging as well as awareness of the typical imaging features of this entity are crucial in making the correct diagnosis as well as excluding other potential considerations such as neoplasm.

Skin type and nerve effects on cortical tactile processing: a somatosensory evoked potentials study

Somatosensory evoked potential (SEP) studies typically characterize short-latency components following median nerve stimulations of the wrist. However, these studies rarely considered 1) skin type (glabrous/hairy) at the stimulation site, 2) nerve being stimulated, and 3) middle-latency (>30 ms) components. Our aim was to investigate middle-latency SEPs following simple mechanical stimulation of two skin types innervated by two different nerves. Eighteen adults received 400 mechanical stimulations over four territories of the right hand (two nerves: radial/median; two skin types: hairy/glabrous skin) while their EEG was recorded. Four middle-latency components were identified: P50, N80, N130, and P200. As expected, significantly shorter latencies and larger amplitudes were found over the contralateral hemisphere for all components. A skin type effect was found for the N80; glabrous skin stimulations induced larger amplitude than hairy skin stimulations. Regarding nerve effects, median stimulations induced larger P50 and N80. Latency of the N80 was longer after median nerve stimulation compared with radial nerve stimulation. This study showed that skin type and stimulated nerve influence middle-latency SEPs, highlighting the importance of considering these parameters in future studies. These modulations could reflect differences in cutaneous receptors and somatotopy. Middle-latency SEPs can be used to evaluate the different steps of tactile information cortical processing. Modulation of SEP components before 100 ms possibly reflects somatotopy and differential processing in primary somatosensory cortex.NEW & NOTEWORTHY The current paper highlights the influences of stimulated skin type (glabrous/hairy) and nerve (median/radial) on cortical somatosensory evoked potentials. Mechanical stimulations were applied over four territories of the right hand in 18 adults. Four middle-latency components were identified: P50, N80, N130, and P200. A larger N80 was found after glabrous skin stimulations than after hairy skin ones, regardless of the nerve being stimulated. P50 and N80 were larger after median than radial nerve stimulations.

Temporal Changes in Electrophysiological Parameters in Untreated Patients With Carpal Tunnel Syndrome

INTRODUCTION

Carpal tunnel syndrome (CTS) is a common entrapment neuropathy worldwide. This study aimed to investigate the temporal changes in electrophysiological parameters in untreated patients with CTS.

METHODS

Patients were recruited among those with the symptoms of CTS who were referred to the electrophysiology laboratory of Niğde Ömer Halisdemir University Bor Physical Therapy and Rehabilitation Hospital in Niğde, Turkey. Forty-nine patients (78 hands) who had not received any sort of treatment for CTS and had prior electrophysiological examination postive for CTS were included. Laboratory records were reviewed retrospectively. Recent electrophysiological parameters of the patients were compared to their prior examinations using Wilcoxon signed-rank test and sign test was used to compare the change in the electrophysiological severity of the study hands between two examinations. One-way analysis of variance (ANOVA) was used to compare individual parameters of the median NCS among electrophysiological change groups (improved, deteriorated, and same).

RESULTS

The mean age was 50 ± 11 years, and 43 (88%) patients were female. The mean duration of time between the two electrophysiological examinations was 37 ± 20 months. Median sensory peak latency and median motor distal latency increased significantly in the second evaluation (p=0.005 and p=0.004, respectively). Median sensory conduction velocity decreased in the second examination (p=0.002). However, CTS severity determined electrophysiologically did not differ significantly in the two examinations (p=0.286).

CONCLUSION

Although there was a deterioration in electrophysiological parameters during a mean follow-up period of 37 months, the electrophysiological severity of the patients did not worsen.

Does hot pack application change the morphology of the median and ulnar nerves?

Objectives

This study aims to investigate the effect of the hot pack application on the morphology of healthy median and ulnar nerves.

Patients and methods

Between August 2021 and September 2022, a total of 54 healthy volunteers (17 males, 37 females; mean age: 31.9±9.4 years; range, 21 to 63 years) were included in the study. The cross-sectional area (CSA) and depth of the right median and ulnar nerve were measured using ultrasonography before and after 20-min hot pack application. The right median nerve CSA and depth from the level of the scaphoid bone (at the level of the carpal tunnel) and from the mid-forearm were also measured. The right ulnar nerve CSA and depth from the level of the hook of hamate and the mid-forearm were evaluated. The depth measurements between the skin and the outer hyperechoic border of the nerve were performed.

Results

After the hot pack application, there was an increase in both the median nerve CSA at the carpal tunnel (from 0.06±0.01 to 0.09±0.02 cm2 ) and forearm (from 0.06±0.02 to 0.09±0.02 cm2 ) levels (p<0.001) and the ulnar nerve CSA at the hook of hamate (from 0.04±0.03 to 0.06±0.01 cm2 ) and forearm (0.05±0.01 to 0.08±0.02 cm2 ) levels (p<0.001). No statistically significant difference was observed between the pre- and post-application depth measurements (p>0.05).

Conclusion

Our study results show that the hot pack application leads to acute swelling of the median and ulnar nerves. In future studies, the relationship between morphological changes in healthy and pathological nerves and electrodiagnostic findings should be investigated.

Proximity of the Ulnar Neurovascular Structures in Endoscopic Carpal Tunnel Release Surgery: A Cadaveric Study

PURPOSE

To evaluate the proximity of the ulnar neurovascular structures to the endoscopic blade during endoscopic carpal tunnel release (CTR).

METHODS

Ten fresh-frozen cadaver hands were used to perform endoscopic CTR using devices from two manufacturers. The skin was excised from the palm, and the endoscopic carpal tunnel blade was deployed at the distal edge of the transverse carpal ligament (TCL). The blade's proximity to the ulnar neurovascular bundle, deep ulnar motor branch, superficial palmar arch, and median nerve was recorded. Following release of the TCL, the device was turned ulnar to the maximal extent to determine if direct injury to the ulnar neurovascular bundle was possible.

RESULTS

The average longitudinal distance from the end of the TCL to the superficial palmar arch was 13.3 mm (range, 8.4-20.9) and to the ulnar motor branch was 10.8 mm (range, 4.0-15.0). The average transverse distance from the end of the TCL to the ulnar neurovascular bundle was 5.9 mm (range, 3.1-7.8) and to the median nerve was 3.3 mm (range, 0-6.5). In two of our specimens, the median nerve subluxated volarly over the cutting device. When placing the blade at the distal edge of the TCL, injury to the deep motor branch of the ulnar nerve, ulnar neurovascular bundle, or superficial palmar arch was not possible in any specimens using the tested devices, even when turning the blade directly toward these structures.

CONCLUSIONS

There is a low likelihood of direct injury to the ulnar neurovascular bundle during endoscopic CTR.

CLINICAL RELEVANCE

These results suggest that injury to the ulnar neurovascular bundle is unlikely during endoscopic CTR if the distal aspect of the transverse carpal ligament can be clearly identified prior to release. Control of the median nerve is also important to prevent subluxation over the cutting device.

Supracondylar Apophysis of the Humerus: Rare Cause of High Compression of the Median Nerve

Supracondylar apophysis (SA) is a bony prominence that originates from the anteromedial aspect of the distal humerus with a lower projection and which, although usually asymptomatic, due to the relationship with adjacent structures can cause symptoms. We describe the case of a 42-year-old woman with pain complaints radiating from her elbow to her hand, with 6 months of evolution. On objective examination, the patient had a sensory deficit in the median nerve territory and decreased grip strength. Radiographs of the distal humerus were performed, in which a bone spike was visible, and magnetic resonance imaging showed thickening of the median nerve epineurium. Electromyography showed severe axonal demyelination of the median nerve proximal to the elbow. A median nerve compression caused by a SA was diagnosed. The patient underwent surgery and, 1 year after the operation, she had a complete clinical recovery. Supracondylar apophysis is a rare, but possible and treatable cause of high median nerve compression.

A Bilateral Symmetric Accessory Coracobrachialis Muscle Combined With an Interconnection of the Musculocutaneous Nerve With the Median Nerve

This report describes a bilateral symmetric accessory coracobrachialis muscle variant coexisting with a unilateral interconnection of the musculocutaneous nerve and the median nerve. An 80-year-old female cadaver was dissected. The bilateral coracobrachialis muscle variant consisted of three heads: two superficial heads and one deep head. One superficial head arose from the tip of the coracoid process, while the other originated from the short head tendon of the biceps brachii. The deep head of the coracobrachialis muscle emerged from the base of the coracoid process. The musculocutaneous nerve bilaterally coursed between the superficial and deep heads. On the right side, the three-headed coracobrachialis muscle coexisted with an ipsilateral interconnection of the musculocutaneous nerve and the median nerve, located at the lower third of the arm. While the presence of a unilateral three-headed coracobrachialis muscle is not rare (with a prevalence range of 0-22.2%), as well as the distal interconnection between the musculocutaneous nerve and the median nerve at the lower third of the arm (with a prevalence range of 1.8-53.6%), the coexistence of the current bilateral three-headed coracobrachialis muscle variant with the distal interconnection of the musculocutaneous and median nerves is quite unusual. A similar report underscores the finding of the bilateral coracobrachialis muscle variant.

Sonographic evaluation of median nerve cross-sectional area in a normal Iranian population: A cross-sectional study

Introduction

Considering disagreements on the normal range of median nerve cross-sectional area (MNCSA) and insufficient data in the Iranian population, this study aimed to measure normal MNCSA.

Methods

In this cross-sectional study, bilateral upper limbs of 99 subjects were assessed by sonography, and MNCSA was measured at three levels: forearm, carpal tunnel inlet (CTI), and carpal tunnel outlet (CTO). The association between MNCSA and demographic factors was assessed.

Results

Mean MNCSA was 6.33 mm² at the forearm, 9.41 mm² at CTI, and 10.67 mm² at CTO. MNCSA was significantly higher in males (6.78 vs. 5.94 mm² at the forearm, 9.98 vs. 8.92 mm² at CTI, and 11.24 vs. 10.84 mm² at CTO in males and females, respectively) and taller (>170 cm) subjects in all three levels (6.69 vs. 6.03 mm² at the forearm, 9.80 vs. 9.02 mm² at CTI, and 11.27 vs. 10.12 mm² at CTO in taller and shorter subjects, respectively). MNCSA was not significantly associated with wrist ratio (WR) or body mass index (BMI).

Conclusion

The normal MNCSA range in the Iranian population is 6.31 mm² (forearm) to 10.74 mm² (CTO). MNCSA is significantly higher in males and taller subjects but is not associated with BMI and WR.

The Application of Ultrasound Image-Based Radiomics in the Diagnosis of Mild Carpal Tunnel Syndrome

OBJECTIVES

The ultrasound diagnosis of mild carpal tunnel syndrome (CTS) is challenging. Radiomics can identify image information that the human eye cannot recognize. The purpose of our study was to explore the value of ultrasound image-based radiomics in the diagnosis of mild CTS.

METHODS

This retrospective study included 126 wrists in the CTS group and 88 wrists in the control group. The radiomics features were extracted from the cross-sectional ultrasound images at the entrance of median nerve carpal tunnel, and the modeling was based on robust features. Two radiologists with different experiences diagnosed CTS according to two guidelines. The area under receiver (AUC) operating characteristic curve, sensitivity, specificity, and accuracy were used to evaluate the diagnostic efficacy of the two radiologists and the radiomics model.

RESULTS

According to guideline one, the AUC values of the two radiologists for CTS were 0.72 and 0.67, respectively; according to guideline two, the AUC were 0.73 and 0.68, respectively. The radiomics model achieved the best accuracy when 16 important robust features were selected. The AUC values of training set and test set were 0.92 and 0.90, respectively.

CONCLUSIONS

The radiomics label based on ultrasound images had excellent diagnostic efficacy for mild CTS. It is expected to help radiologists to identify early CTS patients as soon as possible, especially for inexperienced doctors.

Carpal Tunnel Syndrome: Neuropathic Pain Associated or Not with a Nociplastic Condition

Carpal tunnel syndrome (CTS) has been traditionally classified as primarily a neuropathic condition with or without pain. Precision medicine refers to an evidence-based method of grouping patients based on their susceptibility to biology, prognosis of a particular disease, or in their response to a specific treatment, and tailoring specific treatments accordingly. In 2021, the International Association for the Study of Pain (IASP) proposed a grading system for classifying patients into nociceptive, neuropathic, or nociplastic phenotypes. This position paper presents data supporting the possibility of subgrouping individuals with specific CTS related-pain into nociceptive, neuropathic, nociplastic or mixed-type phenotypes. Carpal tunnel syndrome is a neuropathic condition but can also be comorbid with a nociplastic pain condition. The presence of extra-median symptoms and the development of facilitated pain processing seem to be signs suggesting that specific CTS cases can be classified as the nociplastic pain phenotype. The clinical responses of therapeutic approaches for the management of CTS are inconclusive. Accordingly, the ability to identify the predominant pain phenotype in patients with CTS could likely be problematic for producing efficient treatment outcomes. In fact, the presence of a nociplastic or mixed-type pain phenotype would explain the lack of clinical effect of treatment interventions targeting the carpal tunnel area selectively. We propose a clinical decision tree by using the 2021 IASP classification criteria for identifying the predominant pain phenotype in people with CTS-related pain, albeit CTS being a priori a neuropathic pain condition. The identification of a nociplastic-associated condition requires a more nuanced multimodal treatment approach to achieve better treatment outcomes.

Transscaphoid Transcapitate Perilunate Fracture-dislocation with Inferior Arc Injury and Acute Ulnar Nerve Compression: A Case Report

Introduction

Perilunate dislocations and perilunate fracture-dislocations (PLFD) are relatively uncommon injuries, comprising <10% of wrist injuries. Perilunate injuries are often complicated by median neuropathy reported in 23-45% of cases, whereas there are very few reported cases of associated ulnar neuropathy. Combined greater arc and inferior arc injuries are also rare. We report an unusual PLFD pattern with associated inferior arc injury and acute ulnar nerve compression.

Case Report

A 34-year-old male sustained a wrist injury after a motorcycle collision. Computed tomography scan revealed a trans-scaphoid, transcapitate, perilunate fracture-dislocation, and a distal radius lunate facet volar rim fracture with radiocarpal subluxation. Examination revealed acute ulnar neuropathy without median neuropathy. He underwent urgent nerve decompression and closed reduction, followed by open reduction internal fixation the next day. He recovered without complication.

Conclusion

This case emphasizes the importance of a thorough neurovascular examination to rule out less commonly seen neuropathies. With up to 25% of perilunate injuries misdiagnosed, surgeons should have a low threshold for advanced imaging in high-energy injuries.

An Integrated Review of Carpal Tunnel Syndrome: New Insights to an Old Problem

Carpal tunnel syndrome (CTS) is a common entrapment neuropathy characterized by pain, numbness, and impaired function of the hand due to compression of the median nerve at the level of the wrist. Although CTS can develop from repetitive strain, injury, or medical conditions, there are also congenital and genetic risk factors that can predispose individuals to the condition. With respect to anatomical factors, some individuals are born with a smaller carpal tunnel, which increases their susceptibility to median nerve compression. Variations in specific genes, such as those encoding proteins involved in extracellular matrix remodeling, inflammation, and nerve function, have also been linked to an increased risk for CTS. CTS is associated with a high cost of health care maintenance and loss of work productivity. Therefore, it is vital that primary care physicians fully understand the anatomy, epidemiology, pathophysiology, etiology, and risk factors of CTS, so they can be proactive in prevention, diagnosing, and guiding proper treatment. This integrated review also provides insights into how biological, genetic, environmental, and occupational factors interact with structural elements to determine who is most likely to acquire and suffer from CTS. Keeping health practitioners abreast of all the factors that could impact CTS should go a long way in decreasing the health care and socioeconomic burden of CTS.

Rare peripheral nerve tumor of the median nerve

Peripheral nerve tumors of the median nerve are uncommon. We present a case of a large atypical intraneural perineurioma of the median nerve. In our case, a 27-year-old man with a history of Asperger's and Autism who was diagnosed with a lipofibromatous hamartoma of the median nerve after a biopsy and treated conservatively presented to clinic due to the slowly growing size of his lesion. He was treated with excision of the lesion with associated resection of healthy median nerve and extensor indicis pollicis oppponenplasty. The pathology of the excision reported the lesion as an intraneural perineurioma instead of a lipofibromatous hamartoma perhaps presenting evidence of a reactive process.

Pilot Cadaveric Study of Anatomical Variations of the Median Nerve at the Wrist in the Lithuanian Population

INTRODUCTION

 Carpal tunnel syndrome (CTS) is known as one of the most common neurological disorders in the human body. Nowadays, the prevalence in the general population ranges between 1% and 5%. Due to its high prevalence and increasing incidence of carpal tunnel surgery, the anatomical variations of the median nerve at the wrist are important to know to avoid iatrogenic injury of the nerve.

PURPOSE

The objective of this study was to evaluate the anatomical variation of the median nerve at the level of the wrist in the Lithuanian population with a focus on its thenar motor branch based on the classifications of Lanz.

MATERIAL AND METHODS

A cadaveric study was performed, and 30 wrists of 15 adult Lithuanian cadavers ranging from 70 to 89 years of age were dissected and examined. Eight female and seven male cadavers were included in the study. Any anatomical finding was documented, and the results were compared with the classification of Lanz as well as with the data found in the literature.

RESULTS

All hands showed different patterns in comparison to the standard anatomical variation Lanz type 0. The most common result was dedicated to Lanz group 4A. Nineteen out of 30 hands (63%, p<0.01) had an accessory branch proximal to the carpal tunnel, while one of these hands showed a third thenar motor branch. Five hands (16%) were dedicated to Lanz group 2 with an accessory branch distal to the carpal tunnel. One hand (3%) showed a variation close to Lanz group 2, but in this case, the thenar motor branch had its origin under the flexor retinaculum instead of proximal to it. Two hands each (6%) were classified by Lanz groups 1B and 3A. Additionally, one variation showed a pattern of a combination of Lanz types 3A and 3B. The bifid median nerve had a connecting branch in between which started distal to the flexor retinaculum. Two anatomical variations (6%) were not described by the classification of Lanz.

The significance of wrist immobilization for endoscopic carpal tunnel release

Background

Over the years, endoscopic carpal tunnel release (ECTR) has gained significant interest as an alternative to surgery. However, no consensus has been reached on the necessity of postoperative wrist immobilization. This study aims to compare the outcomes of wrist immobilization for a period of 2 weeks to immediate wrist mobilization after ECTR.

Methods

A total of 24 patients with idiopathic carpal tunnel syndrome undergoing dual-portal ECTR from May 2020 to Feb 2022 were enrolled and randomly divided into two groups postoperatively. In one group, patients wore a wrist splint for 2 weeks. In another group, wrist mobilization was allowed immediately after surgery. The two-point discrimination test (2PD test); the Semmes-Weinstein monofilament test (SWM test); the occurrence of pillar pain, digital and wrist range of motion (ROM); grip and pinch strength; the visual analog score (VAS), the Boston Carpal Tunnel Questionnaire (BCTQ) score; the Disabilities of the Arm, Shoulder, and Hand (DASH) score; and complications were evaluated at 2 weeks and 1, 2, 3, and 6 months after the surgery.

Results

All 24 subjects finished this study with no dropouts. During the early follow-up, patients with wrist immobilization demonstrated lower VAS scores, lower occurrence of pillar pain, and higher grip and pinch strength compared with the immediate mobilization group. No significant difference was obtained between these two groups in terms of the 2PD test, the SWM test, digital and wrist ROM, BCTQ, and the DASH score. In total, two patients without splints reported transient scar discomfort. No one complained of neurapraxia, injury of the flexor tendon, median nerve, and major artery. At the final follow-up, no significant difference was found in any parameters between both groups. The local scar discomfort mentioned above disappeared and left no serious sequela.

Conclusion

Wrist immobilization during the early postoperative period demonstrated significant pain alleviation along with stronger grip and pinch strength. However, wrist immobilization yielded no obvious superiority regarding clinical outcomes at the final follow-up.

Anatomical considerations and clinical implications of bicipital aponeurosis: A magnetic resonance imaging study

The bicipital aponeurosis (BA) is the distal aponeurosis of the biceps brachii which usually covers the median nerve (MN), and the brachial artery (BrA) and sometimes causes compression of these structures. Since these situations are rarely reported in the literature, BA frequently does not come to mind as a cause of such compression. Therefore, the diagnosis may be delayed. In this study, we aimed to investigate the morphometry of BA and its relationship with the surrounding neurovascular structures and to draw attention to BA as a structure that can cause entrapment of the MN and rarely, the BrA. We examined the MRIs of the elbow of 279 patients (107 women, 172 men) aged between 18 and 72 years. We measured the thickness, length and width of BA, and investigated the anatomical relationship between BA, BrA, and MN. The respective median thickness, width, and length of BA were 0.7 (0.4-1.8 mm), 18.0 (6.0-34.0 mm), and 32.0 (18.0-50.0 mm), respectively. In all sections examined, the BA covered the BrA and MN, and was located immediately anterior to the BrA. In 225 (80.6%) of 279 MRIs, the BrA was located anterior to the MN and posterior to the BA. In the remaining 54 (19.4%) MRIs, the MN was located anterior to the BrA and posterior to the BA. The respective median thickness, width, and length of the BA were 0.7 mm, 18.0 mm, and 32.0 mm, respectively. It covered the BrA and MN and was located immediately anterior to the BrA. The BA sometimes causes compression syndromes of these structures, therefore, for physicians, it is important to understand the anatomy of the BA.

Morphological and electrophysiological evaluation of median and ulnar nerve in complex regional pain syndrome type 1

OBJECTIVE

Complex regional pain syndrome (CRPS) can be distinguished as type I without and type II with electrophysiological evidence of major nerve lesion. The pathophysiology of both subgroups is still under investigation. The aim of this research is to demonstrate the nerve morphology and electrophysiology in CRPS type I patients.

MATERIALS AND METHODS

Bilateral median and ulnar nerve cross-sectional areas were evaluated with ultrasound and also median and ulnar nerve conduction studies of both hands were performed. Cross-sectional areas of median and ulnar nerves and nerve conduction studies in healthy controls were also obtained and compared with the patients.

RESULTS

Twenty-five male patients and 11 healthy male controls were enrolled in the study. The mean age of the patients was 24.08 ± 5.50 years and controls was 23.18 ± 5.09 (p > 0.05). Compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the diseased side were found significantly lower than the healthy side (p < 0.05). Both median and ulnar nerve distal motor latency values were significantly higher in the patient group (p < 0.05). There was no significant difference in the median and ulnar nerve cross-sectional area when compared with the opposite extremity and healthy volunteers.

CONCLUSION

The lower SNAP and CMAP amplitudes of the median and ulnar nerves compared to the healthy side and the prolongation of the affected side median and ulnar nerve distal motor latencies of the affected individuals may indicate axonal involvement in patients with CRPS type 1. Decreased CMAP amplitudes may also indicate muscle atrophy due to a decrease in the number of functional motor units.

Evaluation of Sympathetic Vasomotor Activity of the Brachial Arteries Using Doppler Ultrasound

BACKGROUND The sympathetic nervous system is principally accountable for peripheral artery regulation, and its effect is that vasospasm occurs in the medium and large arteries of the extremities, resulting in decreased flow of blood. Because of this information of how the body works, our goal is to create a noninvasive and repeatable self-test model that uses Doppler ultrasound examination. MATERIAL AND METHODS The study was conducted on 31 healthy and active participants who volunteered for the study. Written informed consent was obtained from all participants. The baseline diameter and flow rates of the brachial artery from 2 cm superior to the antecubital fossa were determined using a Doppler probe, which remained stationary throughout the experiment, allowing for continuous measurements. Then, to activate the sympathetic fibers, an electrical stimulus was applied for 5 s with an intensity of 10 mA and frequency of 1 Hz at the level of the median nerve at the wrist via the bipolar stimulation electrode. Immediately following the sixth stimulation, the artery diameter and flow rates were assessed again. RESULTS Following the stimulation, a statistically significant decrease in flow rate was observed (P<0.001). Moreover, stimulation resulted in a statistically significant reduction in the diameter of the brachial artery (P<0.001). CONCLUSIONS Our research suggests that Doppler ultrasonography can be routinely used to detect the normal and abnormal functioning of the peripheral sympathetic nervous system.

True ulnar artery aneurysm in the upper arm: A case report and literature review

INTRODUCTION

Ulnar artery aneurysms are rare with less than 250 previously reported in the literature. Most ulnar artery aneurysms occur distally near the palmar arch (hypothenar hammer syndrome). There are five previous reports of true ulnar artery aneurysms in the forearm; however, there are no reported cases of ulnar artery aneurysms proximal to the cubital fossa.

CASE PRESENTATION

An 87-year-old man presented with pain and a rapidly progressive median nerve palsy with a pulsatile mass in the arm. Duplex ultrasound showed an aneurysm of what was thought to be the brachial artery. CT angiography shows a high bifurcating brachial artery and true aneurysm of the ulnar artery proximal to the cubital fossa. The artery was explored and the decision was made to excise the aneurysm and ligate the artery. The patient's symptoms improved and full function was regained.

CONCLUSION

This is a rare case of such a diagnosis in the absence of a history of arterial puncture or trauma. This case demonstrates the value in obtaining detailed imaging in the work-up to aid operative decision making. We highlight the thought processes on the table in our approach to this aneurysm and report a favourable post-operative outcome at follow up.

Ultrasonographic anatomy of the palmar region of the carpus of the dog

The palmar region of the canine carpus may be injured by traumatic, inflammatory, infectious, neoplastic, and degenerative disorders. The normal ultrasonographic anatomic features of the dorsal region of the canine carpus have been published, however information regarding the palmar region is currently lacking. The aims of this prospective, descriptive, anatomic study were (1) to describe the normal ultrasonographic characteristics of the palmar carpal structures in medium to large-breed dogs, and (2) to establish a standardized ultrasonographic protocol for evaluating them. As in the previously published study, the current study consisted of two phases: (1) identification phase, in which the palmar structures of the carpus were identified ultrasonographically in fifty-four cadaveric specimens and an ultrasonographic protocol to examine them was developed; and (2) descriptive phase, in which the ultrasonographic characteristics of the main palmar structures in twenty-five carpi of thirteen living healthy adult dogs were documented. The tendons of the flexor muscles of the carpus and digits, the superficial and deep parts of the retinaculum flexorum, the carpal canal and the median and ulnar neurovascular structures were ultrasonographically identified and described. Findings from the current study can serve as a reference for evaluating dogs with suspected injury involving the palmar carpal region using ultrasonography.

Iatrogenic median and ulnar nerve injuries during carpal tunnel release: clinical, electrodiagnostic, and ultrasound features in 12 patients. Patient series

BACKGROUND

Nerve injuries during carpal tunnel release (CTR) are rare. Electrodiagnostic (EDX) and ultrasound (US) studies may be helpful in evaluating iatrogenic nerve injuries during CTR.

OBSERVATIONS

Nine patients sustained a median nerve injury, and 3 patients experienced ulnar nerve damage. Decreased sensation occurred in 11 patients, and dysesthesia occurred in 1 patient. Abductor pollicis brevis (APB) weakness occurred in all patients with median nerve injury. Of the 9 patients with median nerve injury, the compound muscle action potentials (CMAPs) of the APB and sensory nerve action potentials (SNAPs) of the 2nd or 3rd digit were not recordable in 6 and 5 patients, respectively. Of the 3 patients sustaining ulnar nerve injuries, the CMAPs of the abductor digiti minimi (ADM) and SNAPs of the 5th digit were not recordable in 1 patient; 2 patients showed prolonged latency and decreased amplitude of CMAPs/SNAPs. US studies of 8 patients with a median nerve injury showed a neuroma within the carpal tunnel. One patient underwent surgical repair urgently, and 6 did so after variable intervals.

LESSONS

Surgeons should be cognizant of nerve injuries during CTR. EDX and US studies are useful in evaluating iatrogenic nerve injuries during CTR.

Risk of nerve injury during elbow arthroscopy: ultrasonographic evaluation of preoperative patients

BACKGROUND

To clarify the real risk of nerve injury during elbow arthroscopy, the distances of the radial and median nerves to the elbow joint were investigated using ultrasonography in patients who underwent surgery.

METHODS

A total of 35 patients who underwent arthroscopic surgery of the elbow were investigated. The distances of the nerves to the capsule and bony landmarks were measured using ultrasonography. The radial nerve distances were measured at the capitellum, joint space, radial head, and radial neck levels. The median nerve distances were measured at the trochlear, joint space, and coronoid process levels. The patients were divided into 2 groups: nine patients in the hydrarthrosis (HA) group and 26 patients in the non-hydrarthrosis (non-HA) group. HA was defined as the intra-articular effusion on magnetic resonance imaging scans.

RESULTS

The radial nerve ran closer to the capsule at the radial neck level in the HA group than in the non-HA group (2.0 mm vs. 5.9 mm, P < .01). In the non-HA group, the radial nerve ran closer to the radial head than in the HA group (6.3 mm vs. 8.5 mm, P = .01). The median nerve ran closer to the capsule at the trochlear level in the HA group than in the non-HA group (5.2 mm vs. 8.8 mm, P < .01). Nerves at a distance of ≤2 mm from the capsule were found in 7 patients at the radial neck of the radial nerve and in 2 patients at the trochlear region of the median nerve in the HA group. In the non-HA group, they were found in 3 patients at the radial head and in 1 patient at the joint space of the radial nerve.

CONCLUSIONS

The dangerous locations for nerve injury during elbow arthroscopy vary according to hydrarthrosis, and this risk should be recognized during arthroscopic surgery.

Ultrasound-based measures in carpal tunnel syndrome: What to measure?

Carpal tunnel syndrome (CTS) is the most common peripheral entrapment neuropathy and is caused by compression of the median nerve (MN) at the level of transverse carpal ligament of the volar wrist. Radiomics is an advanced semi-automated image analysis method that is utilized to identify characteristics in the MN that can detect CTS with considerable reproducibility.

Spatial Relationship of the Median Nerve and Transverse Carpal Ligament in Asymptomatic Hands

The spacing between the median nerve and transverse carpal ligament (TCL) within the carpal tunnel can potentially affect the nerve morphology. This study aimed to quantify the spatial relationship between the median nerve and transverse carpal ligament in asymptomatic hands. Twelve subjects were recruited to image the carpal tunnel using robot-assisted ultrasound. The median nerve and TCL were segmented from each image and three-dimensionally reconstructed using kinematic information from the robot. The TCL-median nerve distance, nerve cross-sectional area, circularity, and position were measured along the entirety of the nerve length within the carpal tunnel. Results were averaged at every 5% of nerve length. At the nerve length percentages of 0% (distal), 25%, 50%, 75%, and 100% (proximal), the TCL-median nerve distance (±SD) was 0.7 ± 0.4, 0.7 ± 0.2, 0.5 ± 0.2, 0.5 ± 0.2, and 0.6 ± 0.3 mm, respectively. The corresponding nerve cross-sectional area was 9.4 ± 1.9, 10.6 ± 2.6, 11.2 ± 2.1, 11.2 ± 1.7, and 9.7 ± 1.9 mm2. A one-way analysis of variance showed no significant differences between the respective percentages of nerve length for TCL-median nerve distance (p = 0.219) and cross-sectional area (p = 0.869). Significant (p < 0.0001) but weak correlations were observed between the TCL-median nerve distance with cross-sectional area (r = -0.247) and circularity (r = -0.244). This study shows that the healthy median nerve morphology is consistent along the continuous nerve length within the carpal tunnel, supporting the use of 2D imaging in the evaluation of the healthy nerve.