Retrospective comparison of ultrasound guided percutaneous and open skeletal muscle biopsies.

Abstract

Open skeletal muscle biopsy has been the mainstay of sample retrieval in patients with suspected muscle diseases. However, this technique is limited by surgeon and theatre availability, potentially resulting in delayed diagnosis and increasing hospital stay. To compare the effectiveness and timeliness of ultrasound guided 14-gauge needle percutaneous muscle biopsy in comparison with open biopsy. We performed a retrospective chart review on 19 inpatients who underwent ultrasound-guided percutaneous muscle biopsy using a 14-gauge needle and 19 consecutive inpatients who underwent open surgical muscle biopsy between January 2017 and June 2019. Patient demographics, length of stay, biopsy sample size and the correlation between histological and clinical diagnosis were compared between groups. The median age of both groups was 64 years. Seventy-nine percent of surgical patients were female compared with 58% who had percutaneous biopsy. Surgical biopsies yielded larger samples (median 864 mm3 vs 17 mm3 , P = 0.03). While there was no difference in the length of inpatient stay (median 8 days), patients who had percutaneous biopsy had a shorter referral to procedure time (median 3 days vs 5 days, P = 0.012). Eighty-four percent of patients underwent MRI prior to percutaneous muscle biopsy, whereas only 16% had imaging before surgical biopsy (P ≤ 0.001). Most surgical biopsies were performed on the quadriceps whereas a wide range of muscles were sampled using the percutaneous technique. Overall, the percutaneous muscle sample was non-diagnostic in five cases (26%) despite a clinical diagnosis of myopathy. By comparison, two surgically obtained samples (11%) were non-diagnostic. Ultrasound guided percutaneous muscle biopsies were performed faster and a wider range of muscles were targeted. However, this technique yielded smaller samples, which were non-diagnostic in 26% of cases. Increasing the needle gauge or number of passes may improve the diagnostic yield of this technique.