A reliable technique for ultrasound‐guided perineural injection in ulnar neuropathy at the elbow

Introduction: Ulnar neuropathy at the elbow (UNE) is a common peripheral compression neuropathy and, in most cases, occurs at 2 sites, the retroepicondylar groove or the cubital tunnel. With regard to a potential therapeutic approach with perineural corticosteroid injection, the aim of this study was to evaluate the distribution of injection fluid applied at a standard site. Methods: We performed ultrasound‐guided (US‐guided) perineural injections to the ulnar nerve halfway between the olecranon and the medial epicondyle in 21 upper limbs from 11 non‐embalmed cadavers. In anatomic dissection we investigated the spread of injected ink. Results: Ink was successfully injected into the perineural sheath of the ulnar nerve in all 21 cases (cubital tunnel: 21 of 21; retroepicondylar groove: 19 of 21). Conclusion: US‐guided injection between the olecranon and the medial epicondyle is a feasible and safe method to reach the most common sites of ulnar nerve entrapment. Muscle Nerve 56 : 237–241, 2017     

Ultrasound combined with electrodiagnosis improves lesion localization and outcome in posterior interosseous neuropathy

Introduction: Posterior interosseous nerve (PIN) syndrome is a rare compression neuropathy. Electrodiagnostic studies (EDx) combined with neuromuscular ultrasound (US) enable precise lesion localization and may improve patient outcome. Methods: In 4 patients with finger extension weakness, US was used to accurately localize concentric electromyographic (EMG) needle placement in PIN muscles and to visualize the lesion site. Results: EMG with US guidance showed decreased recruitment with abnormal configuration in PIN muscles. Active denervation was not always observed. US scanning demonstrated larger PIN diameter in the affected arm. All patients had surgical intervention to confirm EDx and US findings and had improved outcome on follow‐up. Conclusion: These cases demonstrate the benefits of augmenting EDx with US by guiding accurate electrode localization and providing diagnostic information about lesion location. Muscle Nerve 52 : 1117–1121, 2015     

Manual needle placement: Accuracy of botulinum toxin a injections

Introduction: Electrophysiological or ultrasound guidance can facilitate botulinum toxin A (BoNt‐A) injection accuracy, but clinical landmarks and palpation are often used for superficial muscles. We evaluated the accuracy of manual needle placement in the gastrocnemius muscles (GC) guided only by anatomical landmarks and palpation. Methods: Bilateral limbs from 30 cadavers were used to evaluate ink injection into the GC. One anatomist and one orthopedic surgeon verified the accuracy of manual needle placement postinjection by calf muscle dissection. Injection was considered a failure if the ink was not located in the head of the target GC. Results: One hundred twenty‐one practitioners were evaluated. Fifty‐two injections were successful (43%), and 69 failed (57%). This result was unrelated to injector experience (P = 0.097). Conclusions: Our findings show a poor success rate, regardless of injector experience. Therefore, muscle palpation and anatomical landmarks are insufficient to ensure the accuracy of BoNt‐A injections, even for large, superficial muscles. Muscle Nerve 46: 531–534, 2012     

Elimination of dysphagia using ultrasound guidance for botulinum toxin injections in cervical dystonia

Introduction: Dysphagia is a common side effect after botulinum toxin injections for cervical dystonia, with an incidence of 10–40%, depending upon the study and dose used. Methods: Our study consisted of 5 preselected women who met criteria for cervical dystonia and subsequent dysphagia after electromyography (EMG)‐guided injections. Injections were performed with ultrasound (US) imaging, and the effects on swallowing were examined. Separately, sternocleidomastoid (SCM) thickness in healthy controls and treated patients was measured. Results: There were 34 episodes of dysphagia over 98 injection sessions using EMG guidance for a cumulative rate of 34.7%. Using US plus EMG guidance, there was 0% dysphagia across 27 injection sessions. SCM thickness was <1.1 cm. Conclusion: US combined with EMG guidance eliminated recurrent dysphagia after botulinum toxin treatment, possibly by keeping the injectate within the SCM. Muscle Nerve 46: 535–539, 2012     

Ultrasound evaluation in transthyretin‐related amyloid neuropathy

Introduction: Familial amyloid polyneuropathy is a rare condition caused by mutations of the transthyretin gene (TTR). We assessed the pattern of nerve ultrasound (US) abnormalities in patients with TTR‐related neuropathy. Methods: Seven patients with TTR‐related neuropathy (TTR‐N) and 5 asymptomatic TTR‐mutation carriers (TTR‐C) underwent neurological examination, nerve conduction studies, and US evaluation. Results: Multifocal US abnormalities were identified in 6 of 7 TTR‐N patients. A single patient with only a mild sensory polyneuropathy had normal nerves on US evaluation. In the TTR‐C, we only detected an enlarged ulnar nerve at the elbow. Interestingly, disease severity correlated with number of nerves affected on US evaluation. Conclusions: No specific pattern of US abnormalities was identified in this cohort. However, in TTR‐related amyloid neuropathy, US may be a helpful tool in monitoring disease progression, and/or clinical response to pharmacological treatment. Muscle Nerve 50 : 372–376, 2014     

High‐resolution ultrasound visualization of the subcutaneous nerves of the forearm: A feasibility study in anatomic specimens

Introduction: The aim of this ultrasound‐anatomical study was to evaluate the ability of high‐resolution ultrasound (HRUS) to visualize and infiltrate small subcutaneous nerves of the forearm in anatomic specimens. Methods: Seven nonembalmed human bodies (4 men, 3 women; mean age at death, 60 years) were included in the study. Two investigators scanned the anatomic specimens using 15‐MHz and 18‐MHz HRUS transducers. The lateral, medial, and posterior antebrachial cutaneous nerves were scanned and interventionally marked with ink using HRUS‐guidance. Subsequently, dissections were performed to assess the anatomical correlation of HRUS findings. Results: All 3 nerves were identified consistently using HRUS. The precision of the ink‐markings was excellent, with good correlation with the small peripheral branches of all 3 nerves. Conclusions: HRUS can identify precisely the small subcutaneous nerves of the forearm and may aid in both diagnosis and therapy in cases of neuropathy. Muscle Nerve 49 : 676–679, 2014     

High‐Resolution ultrasound of the pudendal nerve: Normal anatomy

Introduction: In this study we aimed to determine whether high‐resolution ultrasound (US) can identify the pudendal nerve and its terminal branches. We also attempted to identify the best approach for visualizing these structures. Methods: Normal anatomy of the pudendal nerve was evaluated in 3 cadavers and 20 healthy volunteers proximally at the level of the ischial spine and distally with low‐frequency (2–5‐MHZ ) and high‐frequency (12–7‐MHZ and 17–5‐MHZ ) transducers. Two musculoskeletal radiologists performed the examinations and evaluations. Volunteers were placed in 3 different positions, which allowed different approaches (posterior, medial, and anterior transperineal). A 0–3 scale was used to assess nerve visibility. Results: Visualization of the pudendal nerve at the ischial spine was best when using a medial approach (P < 0.004); the terminal branches were seen best with the anterior approach (P < 0.002). Conclusion: High‐resolution ultrasound (US) can identify the pudendal nerve and its terminal branches. Muscle Nerve 47:403‐408, 2013     

Ultrasound in EMG‐Guided Biopsies: A Prospective,Randomized Pilot Trial

Introduction: At our institution, core muscle biopsies are performed on muscles selected using electromyography (EMG). Ultrasound (US) guidance is not used routinely. The aim of this study was to determine if US guidance of EMG selected muscles would increase the diagnostic yield of the biopsy as compared to the current practice standards. Methods: Two trained physicians performed 40 randomized biopsies (US guided or traditional approach). The amount of tissue obtained in each biopsy was recorded (volume and mass), along with the final pathologic diagnosis in each case and incidence of complications. Results: Forty patients were studied. Sixteen muscle biopsies were done with US guidance; 50% had a definitive diagnosis, and 38% did not. In the non‐US guidance group, 58% had a definitive diagnosis, and 33% did not. Conclusions: US did not provide any additive advantage when used to guide biopsy in a muscle previously selected for biopsy with EMG. Muscle Nerve 54 : 786–788, 2016     

Nerve ultrasound in diabetic polyneuropathy: Correlation with clinical characteristics and electrodiagnostic testing

Introduction: Diabetic polyneuropathy (DPN) is increasingly prevalent in the USA, but nerve ultrasound (US) findings have not been assessed systematically. Our aim was to establish the sonographic characteristics of lower extremity nerves in DPN and correlate them with electrodiagnostic (EDx) findings. Methods: Consecutive patients (n = 25) with evidence of DPN and 25 patient controls without DPN underwent blinded US imaging of the fibular and sural nerves. Nerve cross‐sectional area (CSA), diameter and echogenicity were recorded. Results: There were no differences in fibular or sural nerve CSA, diameter, or echogenicity between the 2 groups. No correlations between nerve CSA and EDx studies were found. In DPN, there were moderate inverse correlations with age (r = ?0.44 sural ankle, r = ?0.39 sural leg, r = ?0.45 fibular ankle). Conclusions: US measurements of lower extremity nerves in DPN do not differ from controls or correlate with EDx findings. Novel US techniques and/or pedal nerve US may be necessary to detect differences. Muscle Nerve 47:379‐384, 2013     

Ultrasound assessment of the sural nerve in patients with neuropathic pain after ankle surgery

Introduction: The sural nerve may be damaged after ankle injury. The aim of our study was to determine the diagnostic utility of high‐resolution sonography in patients with ankle fractures treated by open reduction and internal fixation in whom there was a clinical suspicion of sural neuropathy. Methods: We examined the ultrasound (US) characteristics of patients with and without postsurgical sural neuropathic pain and healthy volunteers. Cross‐sectional area (CSA), echogenicity, and vascularization of the sural nerves were recorded. Results: Fourteen participants and all sural nerves were identified. CSA (P < 0.001) and vascularization (P = 0.002) were increased in symptomatic patients when compared with asymptomatic patients and healthy volunteers. There were no significant differences in nerve echogenicity (P = 0.983). Discussion: US may be a valuable tool for evaluating clinically suspected sural nerve damage after ankle stabilization surgery. Sural nerve abnormalities are seen in patients with postsurgical neuropathic pain. Muscle Nerve 57 : 407–413, 2018     

Peripheral Neuropathy: Assessment of Proximal Nerve Integrity By Diffusion Tensor Imaging

Introduction: We investigated the utility of diffusion tensor imaging (DTI) for detecting neuropathic changes in proximal nerve segments in patients with peripheral neuropathy. Methods: Twenty‐one individuals with (n = 11) and without (n = 10) peripheral neuropathy underwent DTI of a defined sciatic nerve segment. Patients and controls were evaluated by clinical examination and nerve conduction studies at baseline and 6 months after the initial DTI scan. Results: The mean fractional anisotropy (FA) value was significantly lower in sciatic nerves from patients with peripheral neuropathy as compared with controls. Sciatic nerve FA values correlated with clinical disability scores and electrophysiological parameters of axonal damage at baseline and 6 months after MRI scan. Conclusions: DTI‐derived FA values are a sensitive measure to discriminate healthy from functionally impaired human sciatic nerve segments. DTI of proximal nerve segments may be useful for estimating the proximal axonal degeneration burden in patients with peripheral neuropathies. Muscle Nerve 48 : 889–896, 2013     

A case of lateral calcaneal neuropathy: Lateral heel pain

Introduction: Although isolated injury of the sural nerve is frequently reported, entrapment involving the lateral calcaneal branch of the sural nerve (LCSN) is very rare. Methods: We report the case of a 29‐year‐old man with lateral calcaneal neuropathy of the sural nerve without any history of trauma. The diagnosis was based on clinical, electrophysiologic, and radiologic studies, including ultrasonography (US) and MRI. Results: US revealed a spindle‐shaped swelling in the posterior part of the sural nerve around the lateral malleolus. MRI showed a small lesion in the sural nerve close to the lesser saphenous vein around the level of the lateral malleolus. Two months after conservative management, the numbness and tingling in the lateral calcaneal region improved. Conclusions: Entrapment of the LCSN can arise from tight shoes. US is useful for evaluating the cutaneous nerve lesions that may be too small to detect by MRI. Muscle Nerve 54 : 801–804, 2016     

High‐resolution ultrasound visualization of the deep branch of the ulnar nerve

Introduction: The value of imaging the deep branch of the ulnar nerve (DBUN) over its entire course has not been clarified. Therefore, this study evaluates the feasibility of visualizing the DBUN from its origin to the most distal point. Methods: We performed high‐resolution ultrasound (HRUS) with high‐frequency probes (18–22 MHZ ), HRUS‐guided ink marking, and consecutive dissection in 8 fresh cadaver hands. In both hands of 10 healthy volunteers (n = 20), the cross‐sectional area (CSA) was measured at 2 different locations (R1 and R2). Results: The DBUN was clearly visible in all anatomical specimens and in healthy volunteers. Dissection confirmed HRUS findings in all anatomical specimens. The mean CSA was 1.8 ± 0.5 mm² at R1 and 1.6 ± 0.4 mm² at R2. Discussion: This study confirms that the DBUN can be reliably visualized over its entire course with HRUS in anatomical specimens and in healthy volunteers. Muscle Nerve 56 : 1101–1107, 2017     

Median nerve changes following steroid injection for carpal tunnel syndrome

Introduction: Neuromuscular ultrasound is a painless, radiation‐free, high‐resolution imaging modality for assessment of the peripheral nervous system. The purpose of this study was to use neuromuscular ultrasound to assess the changes that occur in the median nerve after steroid injection for carpal tunnel syndrome (CTS). Methods: Ultrasound and nerve conduction studies were performed at baseline and 1 week, 1 month, and 6 months after steroid injection in 19 individuals (29 wrists) with CTS. Results: Significant changes were noted in median nerve cross‐sectional area (P < 0.001), mobility (P = 0.001), and vascularity (P = 0.042) at the distal wrist crease after steroid injection, and the nerve cross‐sectional area correlated with symptom score and electrodiagnostic parameters. Changes in the ultrasonographic parameters were seen within 1 week of injection. Conclusions: These findings suggest neuromuscular ultrasound is potentially helpful for the assessment of individuals undergoing treatment for CTS, as typical changes can be expected after successful treatment injection. Muscle Nerve 44: 25–29, 2011     

Nerve conduction studies in the superficial radial nerve entrapment syndrome

This report reviews the syndrome of entrapment of the superficial branch of the radial nerve (SBRN) in the forearm, and electrodiagnostic techniques to aid in diagnosis are presented. Normal mean radial sensory conduction in the forearm was found to be 61.4 +/- 3.1 m/sec. Three patients are presented. In two of these comparison of conduction in the SBRN to the lateral antebrachial cutaneous nerve (LACN) and contralateral SBRN was abnormal, whereas the absolute SBRN conduction appeared normal. Normal LACN-SBRN difference in the same arm was 1.9 +/- 1.6 m/sec, with a range of 0-7.0 m/sec; mean SBRN difference in opposite arms of the same subject was 1.8 +/- 1.6 m/sec.     

Heterogeneity of root and nerve ultrasound pattern in CIDP patients

ObjectiveThe few published ultrasound (US) studies on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) report diffusely increased cross-sectional area (CSA) of nerves. The data are, however, heterogeneous and correlations with clinical history or disease severity are lacking.MethodsThirty-four patients with CIDP underwent US nerve evaluation by two neurologists blinded to clinical data. US nerve pattern for each patient was defined by a third neurologist blinded to clinical data. Three US classes were identified based on CSA and echogenicity: large nerves with hypoechoic nerves/fascicles (class 1); large nerves with heterogeneous hypo- and hyperechoic fascicles (class 2); normal size nerve but abnormal hyperechoic array (class 3).ResultsIn all patients, US nerve changes were observed: in most of the cases, enlarged nerves or nerve segments were observed. The three ‘classes’ of US nerve changes significantly correlated (R: 0.68, p < 0.001) with disease duration, but not with age or Inflammatory Neuropathy Cause and Treatment (INCAT) disability score.ConclusionsUS may be of adjunctive diagnostic value in CIDP assessment. Nerve morphological changes may mirror the underlying pathophysiological mechanisms and seem to correlate with disease duration.SignificanceThese results offer the possibility of exploring the use of US to assess CIDP disease activity and treatment.     

The perineurium modifies the effects of phenol and glycerol in rat sciatic nerve

Endoneurial cell response and type of nerve fibre damage were studied after perineural injections of 7% phenol-aqua and pure glycerol. Our previous studies have shown that phenol and glycerol induce different types of nerve fibre degeneration after intraneural injections: phenol dissolves axons and Schwann cells inside the basal lamina tubes but glycerol breaks them down into cellular flakes. The current study investigated whether the difference in type of endoneurial damage also appears after perineural application and how the perineurium affects the effect of these neurolytic agents. Rat sciatic nerves were treated with perineural injections of 7% phenol-aqua or pure glycerol and were followed up to 6 months. The results support the previous findings that perineural phenol injection induces damage that covers almost the whole endoneurium, but glycerol injection results in minor subperineurial damage. An ultrastructural study showed that the endoneurial effects are much milder after perineural injection than after intraneural injections. Phenol-induced nerve fibre dissolving was only rarely seen and the nerve fibre damage appeared similar to that after regular Wallerian degeneration in both groups. Axonal regeneration began within 2 weeks of the injections. Endoneurial macrophages were numerous in the damaged area in many individual nerves even at 3–6 months in both groups, which may indicate impaired phagocytotic activity. Regenerating axonal sprouts were seen first at 1 week post injection and Schwann cells proliferated within 2 weeks in both groups. However, the number of axonal sprouts was higher (P=0.002) and the size of the sprouts appeared larger after glycerol injection at 4 weeks post injection. The present study shows that the effects of extraneurally applied neurolytic agents phenol and glycerol are modified by the perineurium. Phenol readily penetrates the perineurium, but glycerol causes only subperineurial damage. The type of damage is rather similar to regular Wallerian degeneration in both groups and the endoneurial effects differ from those seen after intraneural injections.     

AANEM Application

Introduction: We describe the ultrasonographic findings of sciatic nerve endometriosis. Methods: Two premenopausal women with catamenial sciatica symptoms were examined, the first without a history of endometriosis, the second with previously confirmed endometriosis of the ovary. Ultrasonography, extending from the sciatic notch to the level of the ischial tuberosity showed that the sciatic nerve was “engulfed” in a large, perineural, hypoechogenic, inhomogeneous lesion with an irregular contour corresponding to an endometrioma. The nerve was enlarged, but it was discernible within the lesion, except at its most cranial part. MRI of the pelvis showed intrapelvic extension in both patients. Results: The first patient was treated with a gonadotropin‐releasing hormone agonist, leading to complete morphological regression and normalization of nerve structure, parallel with symptomatic resolution. Conclusions: These cases illustrate that ultrasound is a feasible imaging modality for sciatic nerve endometriosis that may even be used to monitor morphological regression of endometrial tissue during treatment. Muscle Nerve 54 : 500–505, 2016     

Preliminary study of sural nerve morphological changes in uremic hemodialysis patients using 22‐MHz high‐frequency ultrasound

Introduction: The aim of this study was to evaluate the ultrasound (US) morphological changes of sural nerves (SNs) of uremic patients on hemodialysis. Methods: Sixty‐six SNs in 33 uremic patients were examined by 22‐MHZ high‐frequency US and routine nerve conduction studies (NCS), and 76 SNs in 38 controls were also examined. Cross‐sectional area (CSA) and maximal fascicular thickness (MFT) of the SNs were measured. Results: The inner parts of the SN were clearly identified in all participants. There were significant increases in CSA and MFT in the patient group (1.86 ± 0.53 mm² and 0.37 ± 0.08 mm, respectively) compared with the control group (1.38 ± 0.25 mm² and 0.32 ± 0.03 mm, respectively) (P < 0.001). Fifty‐seven SNs (86.36%) had abnormal CSAs, and 51 SNs (77.27%) had abnormal MFTs in the patient group, which was higher than NCS abnormalities (66.67%). Conclusions: A 22‐MHZ US can show morphological changes in the SNs of uremic patients and may be a valuable tool. Muscle Nerve, 2012     

Platelet‐rich plasma limits the nerve injury caused by 10% dextrose in the rabbit median nerve

Introduction: We evaluated the effect of platelet‐rich plasma (PRP) injection in a rabbit model of dextrose‐induced median nerve injury. Methods: New Zealand white rabbits (n = 15) were divided randomly into 3 groups. Three different regimens (group 1: 0.1 ml saline; group 2: 10% dextrose with PRP; group 3: 10% dextrose with saline) were injected within the carpal tunnel. Electrophysiological and histological findings were evaluated 12 weeks after the injection. Results: The mean median motor latency in group 3 was significantly longer than that in groups 1 and 2. The cross‐sectional area of the median nerve and subsynovial connective tissue thickness in group 3 were significantly larger than those in groups 1 and 2. Conclusions: PRP injection may be effective in controlling median nerve injury, as demonstrated by improvement in electrophysiological and histological findings 12 weeks after dextrose injection. Muscle Nerve 49 : 56–60, 2014