The yield of sural nerve biopsy in the evaluation of peripheral neuropathies

The diagnostic yield of sural nerve biopsy was evaluated in 120 peripheral neuropathy patients. In 58 (48%) a final diagnosis was reached without biopsy, while 14 (11.5%) remained undiagnosed. Nerve biopsy contributed to the final diagnosis in 20 of the 53 biopsies (38%). In patients with motor conduction velocity below 30 m/s, sural nerve histology was helpful in 65% of biopsies. In patients with milder reduction in conduction biopsy contributed in only 11%. It is concluded that in general neurological population, nerve biopsy is of limited value as a routine diagnostic procedure. However, in patients with marked slowing of conduction velocity, in whom the diagnosis is not immediately apparent, sural nerve biopsy is indicated.     

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     

Diagnostic nerve ultrasound in Charcot–Marie–Tooth disease type 1B

Ultrasound is emerging as a useful tool for evaluation of neuromuscular conditions, because it can provide high‐resolution anatomic information to complement electrodiagnostic data. There have been few studies in which ultrasound was used to assess the peripheral nerves of individuals with Charcot–Marie–Tooth (CMT) disease and none involving CMT type 1B. In this study we compared nerve cross‐sectional area in individuals from a single large family with CMT 1B with normal, healthy controls. We also assessed for cranial nerve enlargement in those with CMT 1B with cranial neuropathies compared to those with CMT 1B without cranial neuropathies. Individuals with CMT 1B have significantly larger median and vagus nerves than healthy controls, but no difference was seen in cranial nerve size between those with versus those without cranial neuropathies. This is the first study to characterize the ultrasonographic findings in the peripheral nerves of individuals with CMT 1B. Muscle Nerve 40: 98–102, 2009     

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     

Postoperative outcomes and reliability of “sensation‐sparing” sural nerve biopsy

Sural nerve biopsy is a valuable tool for the diagnosis of neuropathic disorders. However, concerns of persisting pain and numbness resulting from traditional whole sural nerve biopsy have led to interfascicular dissection techniques with inconsistent benefits over whole nerve biopsy. In this study we describe a novel technique of atraumatic anterior fascicular sural nerve biopsy designed to preserve calcaneal sensation while maintaining diagnostic benefit, without requiring significant interfascicular dissection. A 10‐year chart review was conducted to identify patients who underwent anterior fascicular sural nerve biopsy. Pathology reports were reviewed to confirm specimen adequacy, and clinical notes were reviewed to determine if a diagnosis was rendered. Retrospective questionnaires were conducted to evaluate perioperative and long‐term sequelae and patient satisfaction. The proportion of patients with symptoms involving the heel versus the dorsolateral foot was evaluated with Fisher's exact test. Specimens from all 53 patients were acceptable and permitted a diagnosis. Twenty‐two patients completed the retrospective survey with an average follow‐up of 5 years (1.2–11.4 years). Eight patients (34%) experienced numbness of the dorsolateral foot, and 1 patient (4.5%) reported numbness of the lateral heel that lasted >6 months (P = 0.001). Persistent dorsolateral foot pain and cold sensitivity were reported by 5 patients (22.7%), but no patients reported lateral heel symptoms (P = 0.04). Symptoms were noted by patients most commonly while standing or walking, but they did not result in functional impairment in any case. Atraumatic anterior fascicular sural nerve biopsy predictably preserved essential lateral heel sensation in patients with neuropathic disorders while providing diagnostic utility. Muscle Nerve 40: 603–609, 2009     

Nerve ultrasound protocol in differentiating chronic immune‐mediated neuropathies

Introduction: In this study we evaluated a new neuropathy ultrasound protocol (NUP) for differentiating chronic immune‐mediated neuropathies. Methods: The NUP was evaluated in 110 patients with clinical presentations of chronic immune‐mediated neuropathy. All patients were first evaluated clinically and electrophysiologically and divided into 4 polyneuropathy groups: (a) symmetric demyelinating; (b) symmetric axonal; (c) asymmetric demyelinating; and (d) asymmetric axonal. During step 2, the NUP was evaluated prospectively for all 4 study groups. Results: Overall, the NUP led to correct classification in 42 of 49 (85.7%) patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 13 of 15 (86.9%) with multifocal motor neuropathy (MMN), and 5 of 5 (100%) with multifocal‐acquired demyelinating sensory and motor neuropathy (MADSAM). The NUP had >80% sensitivity and specificity in distinguishing CIDP, MMN, and MADSAM in all 4 study groups. Conclusions: The NUP is a useful addition in the differential diagnosis of chronic immune‐mediated neuropathies in everyday practice. Muscle Nerve 54 : 864–871, 2016     

Conduction block of peripheral nerve using high‐frequency alternating currents delivered through an intrafascicular electrode

Many diseases are characterized by undesired or pathological neural activity. The local delivery of high‐frequency currents has been shown to be an effective method for blocking neural conduction in peripheral nerves and may provide a therapy for these conditions. To date, all studies of high‐frequency conduction block have utilized extraneural (cuff) electrodes to achieve conduction block. In this study we show that high‐frequency conduction block is feasible using intrafascicular electrodes. Muscle Nerve, 2010     

Anatomical study of the iliohypogastric,ilioinguinal, and genitofemoral nerves using high‐resolution ultrasound

Introduction: In this study we aimed to determine whether high‐resolution ultrasound (US) can identify the iliohypogastric (IH), ilioinguinal (II), and genitofemoral (GF) nerves and their relations. Methods: This investigation, initially undertaken in cadavers, was followed by a high‐resolution US study in 30 healthy adult volunteers (180 nerves) by 2 musculoskeletal radiologists on separate occasions, using 2 different approaches (proximal to distal and distal to proximal). A 0–3 scale was used to assess nerve visibility. Location and course of the IH, II, and GF nerves and their relations to adjacent anatomical structures were analyzed. Results: Nerves and their terminal branches were better visualized with the distal‐to‐proximal approach (P < 0.05). Visualization of the terminal branches was possible in up to 60% of volunteers. Conclusions: High‐resolution ultrasound (US) can identify the IH, II, and GF nerves at the level of the abdominal wall and the terminal branches in the majority of volunteers. Muscle Nerve 51 : 42–48, 2015     

Peripheral nerve size in normals and patients with polyneuropathy: An ultrasound study

Ultrasound has been used for visualizing peripheral nerve pathology. Our goal was to use ultrasound to quantitate the sizes of upper extremity nerves along their length in control subjects and patients with neuropathy. We measured median and ulnar nerve cross‐sectional areas (NCSA) in the arms of 190 subjects, including 100 with neuropathies and 90 controls. We found that NCSAs in healthy child and adult controls were greater with increasing height, at proximal sites, and at sites of entrapment. Nerves were enlarged in all Charcot–Marie–Tooth 1A (CMT‐1A) (11 of 11; 100%), most chronic inflammatory demyelinating polyneuropathy (CIDP) (31 of 36; 86%), half of Guillain–Barré syndrome (GBS) (8 of 17; 47%), but few axonal neuropathy (7 of 36, 19%) subjects. In GBS, nerve enlargement occurred early and with minimal electrodiagnostic abnormalities in some patients. We conclude that NCSA measured by ultrasound is a quantifiable marker of nerve features that should be corrected for patient characteristics and nerve site. NCSA is generally larger in demyelinating than it is in axonal polyneuropathies. Muscle Nerve, 2009     

Nerve ultrasound in miller fisher variant of Guillain–Barré syndrome

Introduction: Focal enlargement of the peripheral and spinal nerves, visualized using high‐resolution ultrasound (HRUS), has been reported in early Guillain–Barré syndrome, but not in the Miller Fisher variant. We report the use of HRUS in 2 patients who presented with acute ataxic neuropathy, areflexia, and ophthalmoparesis. Methods: Ultrasound and/or nerve conduction studies (NCS) of peripheral nerves, the vagus, and spinal nerves C5/6 were performed at onset and 2 weeks after immunoglobulin therapy. Results: Both patients fulfilled criteria for diagnosis of Miller Fisher syndrome (MFS). Laboratory findings revealed elevated ganglioside Q1b antibodies in both and an albuminolocytologic dissociation in 1 patient. In addition, 1 patient had NCS evidence for demyelinating neuropathy. However, ultrasound showed focal enlargement in the vagus, the spinal nerves, and/or in the peripheral nerves in both patients. After therapy, nerve enlargement decreased in parallel with clinical improvement. Conclusion: Spinal and/or peripheral nerve enlargement supports the diagnosis of MFS in early phases of the disease. Muscle Nerve 52 : 1106–1110, 2015     

Nerve enlargement after cold exposure: A pilot study with ultrasound imaging

Introduction: Changes of electrophysiogical parameters with regard to cold have been studied intensively but not the morphology of nerves. We explored the effects of cold exposure on median nerve morphology. Methods: Cross‐sectional area (CSA) and depth of the right median nerve were assessed at the carpal tunnel and mid‐forearm levels before and after 15 min ice‐pack application in 34 healthy volunteers. Results: After cooling, mean CSA measurements increased at the carpal tunnel and mid‐forearm levels (from 8.00 to 8.85 and 6.64 to 7.55, respectively, P < 0.05); however, the depth values were similar. Conclusions: These preliminary results revealed that cold exposure may cause acute nerve swelling. Further studies with larger samples will be necessary to confirm our findings, to correlate them with electrophysiological data, and to explore when/how the nerve edema resolves. Muscle Nerve 49:502–505, 2014     

Coexistence of two chronic neuropathies in a young child: Charcot–marie–tooth disease type 1A and chronic inflammatory demyelinating polyneuropathy

We report an 18‐month‐old Charcot–Marie–Tooth type 1A (CMT1A) patient who developed a rapid‐onset neuropathy, with proximal and distal weakness, and non‐uniform nerve conduction studies. The neuropathy responded well to immunomodulation, confirming the coexistence of an inherited and an inflammatory neuropathy. Unexpected clinical and/or electrophysiological manifestations in CMT1A patients should alert clinicians to concomitant inflammatory neuropathy. In addition, this association raises reflections about disease mechanism in CMT1A. Muscle Nerve, 2010