BACKGROUND: Ultrasonography is used to diagnose carpal tunnel syndrome (CTS) according to various criteria. This diagnostic meta-analysis aimed to evaluate the efficacy of ultrasonography for diagnosing CTS, focusing on the cross-sectional area (CSA) of the median nerve (MN) at the inlet of the carpal tunnel and regional variations in diagnostic thresholds between Asian and non-Asian populations.
METHODS: A comprehensive literature search was conducted using PubMed, Embase, and the Cochrane Library. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Patient demographic data, diagnostic \"gold standards\", CSA cutoff values, and diagnostic results were extracted. Meta-analysis was performed to determine the sensitivity, specificity, and optimal CSA cutoff values.
RESULTS: For the 25 included studies, a combined sensitivity of 88% and specificity of 84% for CSA measurements at the carpal tunnel inlet were obtained. The Asian group had a sensitivity of 84% and specificity of 86%, while the non-Asian group had a sensitivity of 91% and specificity of 82%. The mean CSA in the Asian group was significantly lower than that in the non-Asian group (12.93 mm2 and 14.77 mm2, respectively; p = 0.042). For the Asian group, the summary receiver operating characteristic curve had an area under the curve (AUC) of 0.92 with an optimal cutoff of 10.5 mm2; for the non-Asian group, an AUC of 0.94 was obtained with a cutoff of 11.5 mm2.
CONCLUSIONS: Ultrasonography is a reliable diagnostic method for CTS, with distinct optimal cutoff values observed between Asian and non-Asian populations. Therefore, population-specific diagnostic criteria for CTS are recommended.

An 8-year-old Portuguese Water Dog presented with a 5-month history of left forelimb lameness. There was palmar pain. Ultrasonography revealed enlargement of the left median nerve. Subsequent MRI also showed enlargement of the median nerve in the distal palmar to the mid-forearm region. Rapid intraoperative diagnosis suggested Malignant peripheral nerve sheath tumors (MPNST) and a neurotomy was performed. The lameness had almost disappeared in 1 month after surgery. Recurrence occurred 26 months postoperatively and the forelimb was amputated. At 950 days after the neurotomy, radiography revealed lung metastasis, and the dog died 988 days after the neurotomy. Neurotomy for MPNST should be performed with caution until more information is available regarding methods for early detection, margin determination, and indication determination for neurotomy.

BACKGROUND: Connective tissue serves a role beyond mere spatial filling. Furthermore, there is increasing evidence that connective tissue plays an important role in the pathogenesis of conditions such as carpal tunnel syndrome (CTS). According to our hypothesis, the median nerve (MN) is surrounded by a system of connective tissue distal to the pronator teres and extending up to, and including, the carpal tunnel.
METHODS: To visualize the connective tissue surrounding the median nerve, we dissected the forearms of 15 body donors from pronator teres to the carpal tunnel, created plastination slices stained with Periodic Acid-Schiff (PAS), and injected ink into the seen spaces. We verified our findings with a segmentational analysis of radiological data of 10 healthy individuals.
RESULTS: We macroscopically describe the median nerve´s system of connective tissue (MC) distal to the pronator teres and up to and including the carpal tunnel. This system creates, connects, and separates spaces. At least from the pronator teres to the carpal tunnel it also creates subspaces from proximal to distal. For the MC, we established a mean cross-sectional area of 153.1 mm2 (SD=37.15) in the carpal tunnel. The median nerve consistently resides at the center of this MC, which further connects to flexor muscles of the forearm, and to the radius bone. In the carpal tunnel, the MC creates subspaces inside. There, it also acts as the outermost internal layer enveloping flexor tendons, and the MN.
CONCLUSIONS: The term MC does not negate but orders the existence of other \"connectives\", like subsynovial connective tissue, endo-, epi- or perineuria, epimysia, periostea, or peritendinea, to a hierarchy related to the median nerve. Diseases of the MN are common. Knowing the anatomy of the MC and how it relates to MN function may help clinicians recognize and understand conditions like CTS.

OBJECTIVE: Pain often accompanies carpal tunnel syndrome and affects patients\' health-related quality of life. The aim was to develop and validate a predictive model for the pain intensity of carpal tunnel syndrome using demographic, clinical, electrophysiological, and ultrasound findings.
METHODS: We conducted a secondary analysis of data from a large sample of patients (May 2017 to December 2022) with carpal tunnel syndrome. A total of 520 (53.0 %) mild, 276 (28.1 %) moderate, and 186 (18.9 %) severe syndromes were included in the complete data set of 982 hands (61.1 % female). The mean age was 57.8 (10.7) years and the median duration [interquartile range] of the symptoms was 4 [2,10] months. A regression model was developed and validated to predict pain intensity on a numerical rating scale using a tree-based machine learning algorithm.
RESULTS: The validation of the regression model showed good performance with a root mean squared error, R-squared, and mean absolute error of 1.35, 0.42, and 1.05, respectively. Overall, the top significant predictors of pain intensity were compound motor nerve action potential latency, nocturnal pain, and thenar weakness. These were followed by the cross-sectional area of the median nerve, sensory nerve action potential, bowing of the flexor retinaculum, disease duration, and body mass index. We did not find strong associations between the median nerve transcarpal latency, age, sex, and diabetes with the pain intensity of carpal tunnel syndrome.
CONCLUSIONS: Our model showed good performance in predicting the subjective pain intensity of carpal tunnel syndrome, even in the context of non-linear relations.

Carpal tunnel syndrome (CTS) is the most common cause of peripheral compressive neuropathy and consists of compression of the median nerve in the wrist. Although there are several etiologies, idiopathic is the most prevalent origin, and among the forms of treatment for CTS, conservative is the most indicated. However, despite the high prevalence in and impact of this syndrome on the healthcare system, there are still controversies regarding the best therapeutic approach for patients. Therefore, noting that some studies point to vitamin D deficiency as an independent risk factor, which increases the symptoms of the syndrome, this study evaluated the role of vitamin D supplementation and its influence on pain control, physical examination and response electroneuromyography to conservative treatment of carpal tunnel syndrome. For this, the sample consisted of 14 patients diagnosed with CTS and hypovitaminosis D, who were allocated into two groups. The control group received corticosteroid treatment, while the experimental group received corticosteroid treatment associated with vitamin D. Thus, from this study, it can be concluded that patients who received vitamin D, when compared to those who did not receive it, showed improvement in the degree of pain intensity, a reduction in symptom severity and an improvement in some electroneuromyographic parameters.

OBJECTIVE: T2 magnetic resonance imaging (MRI) mapping has been applied to carpal tunnel syndrome (CTS) for quantitative assessment of the median nerve. However, quantitative changes in the median nerve before and after surgery using T2 MRI mapping remain unclear. We aimed to investigate whether pathological changes could be identified by pre- and postoperative T2 MRI mapping of the median nerve in CTS patients after open carpal tunnel release.
METHODS: This was a prospective study that measured median nerve T2 and cross-sectional area (CSA) values at the distal carpal tunnel, hamate bone, proximal carpal tunnel, and forearm levels pre- and postoperatively. Associations between T2, CSA, and nerve conduction latency were also evaluated.
RESULTS: A total of 36 patients with CTS (mean age, 64.5 ± 11.7 years) who underwent surgery were studied. The mean preoperative T2 values significantly decreased from 56.3 to 46.9 ms at the proximal carpal tunnel levels (p = .001), and from 52.4 to 48.7 ms at the hamate levels postoperatively (p = .04). Although there was a moderate association between preoperative T2 values at the distal carpal tunnel levels and distal motor latency values (r = -.46), other T2 values at all four carpal tunnel levels were not significantly associated with CSA or nerve conduction latency pre- or postoperatively.
CONCLUSIONS: T2 MRI mapping of the carpal tunnel suggested a decrease in nerve edema after surgery. T2 MRI mapping provides quantitative information on the median nerve before and after surgery.

Objective  To identify the location of the Riché-Cannieu anastomosis (RCA) in relation to the Cardinal Kaplan Line (KCL) and the Y line. Methods  A total of 20 hands of 10 recently-deceased adult male cadavers aged between 27 and 66 years were dissected for the investigation of the relationship of the most distal point of the RCA with the KCL and with the Y line, drawn from the axis of the third metacarpal head, following the longitudinal axis of the hand. Results  In 20 limbs, the most distal point of the nerve communication was positioned distally in relation to the KCL. The Y line was positioned on the radial side in relation to the most distal point of the RCA in 14 limbs, and it was positioned on the ulnar side in relation to the Y line in 6 limbs. The crossing between the KCL and the Y line occurred proximal to the RCA in 18 limbs; in 1 hand, it was positioned distal to the intersection between these lines; and in another hand, the KCL was positioned exactly on the RCA. Conclusion  Knowledge of these anatomical relationships can prevent damage to nerve branches and thus also prevent paralysis of intrinsic muscles in surgical procedures in the palm of the hand.

Background and objective Several recent studies have explored whether F-waves can be a sensitive and useful tool for diagnosing carpal tunnel syndrome (CTS). In light of this, we aimed to measure the minimal F-wave latencies in patients with mild, moderate, and severe electrophysiologically diagnosed carpal CTS, as well as individuals without CTS, to determine at which point this parameter becomes sensitive to the syndrome. Materials and methods Nerve conduction studies were carried out in a room where a temperature of 22-24 °C was maintained. The F-waves of the median nerve in all patients and individuals in the control group were recorded. The F-wave with the highest velocity (minimal F) was categorized into the normal, mild, moderate, and severe groups for statistical analysis. All measurements were performed by the same electrophysiology-experienced neurologist. Results Post-hoc analysis demonstrated that the F latency values of the moderate and severe CTS groups were significantly higher than those of the control group (p<0.001 for all comparisons). Furthermore, the F latency values of the severe CTS group were significantly higher than those of the moderate group (p=0.026). Conclusions Based on our findings, minimal F-wave latency is a reliable indicator of moderate to severe CTS. This sensitivity significantly increases in severe cases while disappearing in the presence of mild CTS.

This study investigated the reliability of measuring the median nerve cross-sectional area (CSA) at the carpal tunnel inlet using a handheld ultrasound device (HUD) compared to a standard ultrasound system, focusing on intra- and inter-operator reproducibility among novice and expert operators. Employing a prospective cross-sectional design, 37 asymptomatic adults were assessed using both devices, with measurements taken by an expert with over five years of experience and a novice with less than six months. The CSA was determined using manual tracing and ellipse methods, with reproducibility evaluated through intraclass correlation coefficients (ICCs) and agreement assessed via Bland-Altman plots. Results showed a high degree of agreement between the devices, with excellent intra-operator reproducibility (ICC > 0.80) for the expert, and moderate reproducibility for the novice (ICCs ranging from 0.539 to 0.841). Inter-operator reliability was generally moderate, indicating acceptable consistency across different experience levels. The study concludes that HUDs are comparable to standard ultrasound systems for assessing median nerve CSA in asymptomatic subjects, with both devices providing reliable measurements. This supports the use of HUDs in diverse clinical environments, particularly where access to traditional ultrasound is limited. Further research with a larger sample and symptomatic patients is recommended to validate these findings.

OBJECTIVE: The objective of this study was to determine the incidence, necessity for neurosurgical intervention, and overall results of the treatment of pediatric peripheral nerve injuries associated with dislocated supracondylar fractures of the distal humerus.
METHODS: A retrospective analysis of pediatric patients with supracondylar fractures treated from April 2019 to April 2022 with a minimum follow-up of 3 months was conducted.
RESULTS: Of 453 included patients, there were 51 recorded peripheral nerve injuries. The ulnar nerve was the most frequently injured nerve. Nine patients required neurosurgical intervention, with the most common procedure being the release of entrapped nerves. The combination of a supracondylar fracture and arterial injury was identified as a significant risk factor for peripheral nerve injury (p < 0.001). Only one patient experienced an unsatisfactory outcome.
CONCLUSIONS: Although the prognosis for peripheral nerve injuries in children with supracondylar fractures is generally favorable, these injuries must be properly identified. We recommend an active neurosurgical approach in children with persisting neurological deficits to minimize the risk of permanent neurological impairment.