Prevalence of Carpal Tunnel syndrome among dental health care providers -systematic review protocol

Review question / Objective: What is the prevalence of Carpal Tunnel syndrome among dental health care providers? Condition being studied: Carpal tunnel syndrome is median nerve peripheral neuropathy which causes paresthesia, pain, and numbness in territory of median nerve (thumb, index, middle, and lateral half of the ring finger). Information sources: Pubmed, SCOPUS, EMBASE, CINAHL, Web of Sciences, Dentistry and Oral Science Source from inception to January 1st 2022.

Effect of Percutaneous Electric Stimulation with High Frequency Alternating Currents on the Sensory-Motor System of Healthy Volunteers

BackgroundFormer studies investigated the application, both transcutaneous and with implanted electrodes, of high frequency alternating currents (HFAC) in humans for blocking the peripheral nervous system. The present trial aimed to assess the effect of HFAC on motor response, somatosensory thresholds, and peripheral nerve conduction, when applied percutaneously with ultrasound-guided needles at frequencies of 10 kHz and 20 kHz in healthy volunteers. MethodsA parallel, placebo-controlled, double-blind, randomized clinical trial was conducted. Ultrasound-guided HFAC at 10 kHz and 20 kHz and sham stimulation were delivered to the median nerve of 60 healthy volunteers (n=20 per group) for 20 minutes. The main assessed variables were maximum isometric flexion strength (MFFS) of the index finger, myotonometry, pressure pain threshold (PPT), mechanical detection threshold (MDT), and antidromic sensory nerve action potential (SNAP). Measurements were recorded pre-intervention, during the intervention 15 minutes after its commencement, immediately post-intervention, and at 15 minutes post-intervention.ResultsA decrease in the MFFS was observed immediately post-intervention compared to baseline, both in the 10 kHz group [-8.5 %; 95% confidence interval (CI) -14.9 to -2.1] and the 20 kHz group (-12.0%; 95%CI -18.3 to -5.6). At 15 minutes post-intervention, the decrease in the MFFS was -9.5% (95%CI -17.3 to -1.8) and -11.5% (95%CI -9.3 to -3.8) in the 10 kHz and 20 kHz groups, respectively. No changes over time were found in the sham group. The between-group comparison of changes in MFFS showed a greater reduction of -10.8% (95%CI -19.8 to -1.8) immediately post-intervention in the 20 kHz compared to the sham stimulation group. Muscle tone increased over time in both the 10 kHz and 20 kHz groups, but not in the sham group. The intergroup comparison of myotonometry showed a superior effect in the 20 kHz (6.7%, 95%CI 0.5 to 12.9) versus the sham group. No significant changes were observed in the rest of the assessed variables. ConclusionsThe ultrasound-guided percutaneous stimulation applying 10 kHz and 20 kHz HFAC to the median nerve produced reversible reductions in strength and increases in muscle tone with no adverse effects.

Variation of the palmar cutaneous branch of the median nerve identified within the tendon sheath of the flexor carpal radialis

Purpose: During volar plate fixation of distal radius fractures, we have encountered patients with an anomalous course of the palmar cutaneous branch (PCB) of the median nerve within the sheath of the flexor carpi radialis (FCR) tendon. The purpose of this study was to assess the frequency and location of variations of the PCB within the sheath of the FCR tendon.Methods: This retrospective study enrolled 83 patients who underwent volar locking plate fixations through a modified Henry approach for distal radius fractures from July 2018 to April 2020. When we encountered an anomalous PCB within the sheath of the FCR tendon, we documented the specific finding and location where the PCB entered the sheath of the FCR tendon.Results: There were nine patients (10.8%) who had an anomalous course of PCB penetrating the sheath of the FCR tendon. The average entering point of PCB into the sheath of the FCR tendon was 3.07 cm from the distal wrist crease (range, 2.5–3.6 cm).Conclusion: An anomalous course of the PCB entering the sheath of the FCR tendon was observed at a high frequency (10.8%). Care must be taken not to injure the PCB during a dissecting of the FCR sheath during a modified Henry approach for a distal radius fracture.

High-resolution ultrasound in the diagnosis of failed carpal tunnel decompression: a study of 35 cases

We used high-resolution ultrasound to examine 35 median nerves (35 patients) with failed carpal tunnel decompression to identify the cause of failure. The carpal tunnel was examined before revision surgery, and the results were correlated with surgical findings. The cross-sectional area was measured, and nerve morphology was analysed at the sites of compression. We found persistent median nerve compression in 30 out of 35 patients. In 20 patients, the compression was caused by a residual transverse carpal ligament, in four by perineural fibrosis, in five by both of these causes and in one by tenosynovitis. In four patients, evidence of median nerve injury with an epineural/fascicular lesion was detected; and in one, no abnormalities were found. Surgical findings were consistent with the ultrasound findings except in one patient where tenosynovitis was associated with a giant cell tumour, which was missed by ultrasound. High-resolution ultrasound can provide helpful information in preoperative diagnosis of failed carpal tunnel decompression with good correlation between the ultrasound and surgical findings. Level of evidence: IV

Ultrasound Measurements of the Median Nerve at the Distal Wrist Crease Correlate With Electrodiagnostic Studies

Background: Carpal tunnel syndrome (CTS) is the most common nerve entrapment neuropathy and is commonly evaluated using electrodiagnostic studies (EDSs). Ultrasound (US) has emerged as a potentially easier and more comfortable alternative to EDSs. The purpose of this study is to evaluate whether measurements of the cross-sectional area (CSA) of the median nerve via US correlate with the severity rating of CTS based on EDSs. Methods: A retrospective review of patients aged 18 years or older who underwent US and EDSs of the median nerve for CTS was performed. Sensory nerve action potential, distal motor latency, and compound muscle action potential were measured, and severity was graded on American Association of Neuromuscular and Electrodiagnostic Medicine guidelines. Cross-sectional area of the median nerve was measured via US at the wrist crease. Results: There was a significant association between increasing CSA and increasing EDS severity ( P < .0001). The mean CSA for normal, mild, moderate, and severe CTS was 7.48 ± 2.00, 10.36 ± 2.53, 12.01 ± 3.64, and 14.34 ± 4.77 mm2, respectively. The area under the curve demonstrated the ability of median nerve CSA to discriminate between normal and abnormal EDSs with an optimal cutoff CSA of ≥10 mm2, as well as, the ability to discriminate between mild CTS and moderate to severe CTS at a cutoff CSA of greater than or equal to 12 mm2. Conclusions: The results of this study show that US measurements of the median nerve at the distal wrist crease discriminate between normal and abnormal EDSs, and between mild CTS and moderate to severe CTS.

A randomized trial to determine the minimum effective lidocaine volume for median nerve block using hydrodissection

Ultrasound-guided hydrodissection with 5% dextrose in water (DW5) creates a peri-nervous compartment, separating the nerve from the neighboring anatomical structures. The aim of this randomized study was to determine the minimum volume of lidocaine 2% with epinephrine 1:200,000 required when using this technique to achieve an effective median nerve block at the elbow in 95% of patients (MEAV95). Fifty-two patients scheduled for elective hand surgery received an ultrasound-guided circumferential perineural injection of 4 ml DW5 and an injection of local anesthetic (LA) following a biased coin up-and-down sequential allocation method. A successful block was defined as a light touch completely suppressed on the two distal phalanges of the index finger within a 30-min evaluation period. The MEAV95 of lidocaine 2% with epinephrine was 4 ml [IQR 3.5–4.0]. Successful median nerve block was obtained in 38 cases (82.6%) with median onset time of 20.0 [10.0–21.2] minutes (95% CI 15–20). The analgesia duration was 248 [208–286] minutes (95% CI 222–276). Using an ultrasound-guided hydrodissection technique with DW5, the MEAV95 to block the median nerve at the elbow with 2% lidocaine with epinephrine was 4 ml [IQR 3.5–4.0]. This volume is close to that usually recommended in clinical practice.Trial registration clinicaltrials.gov. NCT02438657, Date of registration: May 8, 2015.