Muscle biopsy practices in the evaluation of neuromuscular disease: A systematic literature review

AIMS

Muscle biopsy techniques range from needle muscle biopsy (NMB) and conchotome biopsy to open surgical biopsy. It is unknown whether specific biopsy techniques offer superior diagnostic yield or differ in procedural complication rates. Therefore, we aimed to compare the diagnostic utility of NMB, conchotome and open muscle biopsies in the assessment of neuromuscular disorders.

METHODS

A systematic literature review of the EMBASE and Medline (Ovid) databases was performed to identify original, full-length research articles that described the muscle biopsy technique used to diagnose neuromuscular disease in both adult and paediatric patient populations. Studies of any design, excluding case reports, were eligible for inclusion. Data pertaining to biopsy technique, biopsy yield and procedural complications were extracted.

RESULTS

Sixty-four studies reporting the yield of a specific muscle biopsy technique and, or procedural complications were identified. Open surgical biopsies provided a larger tissue sample than any type of percutaneous muscle biopsy. Where anaesthetic details were reported, general anaesthesia was required in 60% of studies that reported open surgical biopsies. Percutaneous biopsies were most commonly performed under local anaesthesia and despite the smaller tissue yield, moderate- to large-gauge needle and conchotome muscle biopsies had an equivalent diagnostic utility to that of open surgical muscle biopsy. All types of muscle biopsy procedures were well tolerated with few adverse events and no scarring complications were reported with percutaneous sampling.

CONCLUSIONS

When a histological diagnosis of myopathy is required, moderate- to large-gauge NMB and the conchotome technique appear to have an equivalent diagnostic yield to that of an open surgical biopsy.

Ultrasound-guided muscle biopsy: a practical alternative for investigation of myopathy

OBJECTIVE

We propose the use of ultrasound-guided muscle biopsy as a viable method of obtaining muscle specimen to aid the diagnosis of myopathy. We retrospectively review the diagnostic accuracy and patient feedback of ultrasound-guided muscle biopsies in our neuromuscular service.

METHOD

Multidisciplinary team meeting reviewed select patients and agreed on those suitable for ultrasound-guided muscle biopsy. They then underwent biopsy using direct ultrasound guidance and a modified Bergström needle. The specimens were sent for histopathological analysis, and patients were given a feedback form.

RESULTS

Ten patients underwent 11 ultrasound-guided muscle biopsies. Of these 11, one was processed incorrectly, but all others were good quality specimens suitable for analysis. All 10 of those processed correctly aided diagnosis. All patient feedback was rated good or excellent. In 4 patients with a previous unsuccessful surgical biopsy, ultrasound-guided biopsy was successful in obtaining suitable muscle. Of those 4 patients, 3 preferred ultrasound-guided biopsy, and 1 did not state a preference.

DISCUSSION

Our ultrasound-guided muscle biopsy technique offers a viable alternative to surgical biopsy. It yields high-quality specimen that aids diagnosis and receives good feedback from patients. It can be performed quickly as a day case and does not require theatre space. Furthermore, direct visualization of structures minimizes the risk of complications and allows biopsy of otherwise difficult to access targets.

CONCLUSION

Utilization of ultrasound guided-modified Bergström needle technique for muscle biopsy provides comparable success rates to other techniques and has practical, clinical, operational, and patient-centred benefits compared with alternative techniques.

Indications for neuromuscular ultrasound: Expert opinion and review of the literature

Over the last two decades, dozens of applications have emerged for ultrasonography in neuromuscular disorders. We wanted to measure its impact on practice in laboratories where the technique is in frequent use. After identifying experts in neuromuscular ultrasound and electrodiagnosis, we assessed their use of ultrasonography for different indications and their expectations for its future evolution. We then identified the earliest papers to provide convincing evidence of the utility of ultrasound for particular indications and analyzed the relationship of their date of publication with expert usage. We found that experts use ultrasonography often for inflammatory, hereditary, traumatic, compressive and neoplastic neuropathies, and somewhat less often for neuronopathies and myopathies. Usage significantly correlated with the timing of key publications in the field. We review these findings and the extensive evidence supporting the value of neuromuscular ultrasound. Advancement of the field of clinical neurophysiology depends on widespread translation of these findings.

Muscle biopsy technical safety and quality using a self-contained, vacuum-assisted biopsy technique

Muscle sampling via percutaneous biopsy has been shown to be safe and effective using a Bergström needle; however, the use of a single-operator, self-contained, vacuum-assisted biopsy technique has not been explored. We performed a retrospective chart review of muscle biopsy samples obtained using the Vacora® self-contained vacuum-assisted biopsy system between 2013 and 2016, at the Toronto General Hospital. During this period, 102 single-operator muscle biopsies were performed using the Vacora® system. 54/102 showed normal or non-specific findings, while 39/102 were suggestive or diagnostic of a neuromuscular condition. 8 samples did not provide sufficient muscle tissue for diagnosis, and complications (intramuscular hematoma) occurred in 3/102 cases. Mean sample weight was 0.19 grams, which exceeded reported mean sample weights using the suction-modified Bergström technique (0.125 grams). We therefore conclude that the Vacora® vacuum-assisted biopsy system provides a safe and effective method to obtain diagnostic muscle biopsy samples; although complication rates are slightly higher than reported using the Bergström technique, possibly related to more vigorous suction or a sharp needle tip.

Automatic Biopsy Instruments Used through a Coaxial Bone Biopsy System with an Eccentric Drill Tip

Twenty-eight consecutive CT (n=23) or ultrasonographically (n=5) guided biopsy procedures were performed on musculoskeletal lytic lesions covered (n=13) or not covered (n=15) with intact bone. Specimens were obtained by means of Biopty techniques (n=27), i.e. Biopty and Monopty instruments, through different cannulas with normal or shortened needle-throws. Four out of 5 bone penetrations were successful with an Ostycut needle, and all 8 bone penetrations by a coaxial bone biopsy system with an eccentric drill. The eccentric drill makes a hole in the cortical bone larger than the diameter of the outer cannula of this system, making it easy to anchor the cannula and then coaxially insert a Biopty-Gun needle for example. The overall histopathological diagnostic accuracy of the Biopty techniques was 25/27 (92.6%).

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.

Muscle ultrasound in neuromuscular disorders

Muscle ultrasound is a useful tool in the diagnosis of neuromuscular disorders, as these disorders result in muscle atrophy and intramuscular fibrosis and fatty infiltration, which can be visualized with ultrasound. Several prospective studies have reported high sensitivities and specificities in the detection of neuromuscular disorders. Although not investigated in large series of patients, different neuromuscular disorders tend to show specific changes on muscle ultrasound, which can be helpful in differential diagnosis. For example, Duchenne muscular dystrophy results in a severe, homogeneous increase of muscle echo intensity with normal muscle thickness, whereas spinal muscular atrophy shows an inhomogeneous increase of echo intensity with severe atrophy. A major advantage of muscle ultrasound, compared to other imaging techniques, is its ability to visualize muscle movements, such as muscle contractions and fasciculations. This study reviews the possibilities and limitations of ultrasound in muscle imaging and its value as a diagnostic tool in neuromuscular disorders.

Diagnostic yield associated with multiple simultaneous skeletal muscle biopsies

Certain skeletal muscle disorders, such as inflammatory myopathies, may show regional variability, prompting consideration of simultaneous biopsy of more than 1 muscle to increase the likelihood of diagnosis. There are few data in the literature to support this approach. This study is a retrospective 8-year review of 99 cases (52 men; mean age, 61.8 years) who had multiple muscles biopsied simultaneously. The most common clinical symptoms prompting biopsy included weakness in 83 cases and myalgia in 15. The most common diagnoses were as follows: neurogenic atrophy, 48; inflammatory myopathy, excluding inclusion body myositis, 29; and type II muscle fiber atrophy, 24. Diagnoses were the same in both biopsied muscles in 54 cases (55%). In 17 cases, a diagnosis was made from only 1 biopsy. Of 29 inflammatory myopathies and vasculitis (excluding inclusion body myositis), a diagnosis could be made from only 1 of the 2 biopsies in 10 cases (34%). In a significant subset of cases, a potentially treatable inflammatory myopathic condition might have been missed if only 1 site had been biopsied, justifying biopsy of 2 sites in suspected cases of inflammatory myopathy.