Magnetic resonance image-guided transcutaneous focused ultrasound for uterine fibroids

Uterine fibroids are benign tumours of the uterine wall. Fibroids can be asymptomatic or cause symptoms including bleeding, urinary incontinence, pelvic pressure or pain. They can be associated with subfertility and miscarriage.

For symptomatic fibroids, treatment options include hysterectomy, myomectomy, uterine artery embolisation and endometrial ablation techniques.

MRI-guided transcutaneous focused ultrasound for uterine fibroids is carried out with the patient lying prone inside an MRI scanner, using imaging and thermal mapping guidance. The patient is usually under intravenous conscious sedation and is able to communicate with the operator about adverse symptoms such as burning sensations or pain. A catheter is inserted to keep the bladder empty during the procedure.

The head of the ultrasound device is placed in contact with the skin of the patient's lower abdomen. Low-power ultrasound is first used to target the centre of the fibroid, followed (after the aiming has been confirmed) by high-power pulses to ablate part of the fibroid. The patient may have to lie still for up to 3 hours. After treatment, imaging is used to evaluate the volume of the fibroid ablated.

A non-randomised comparative study of 192 patients treated by magnetic resonance image (MRI)-guided transcutaneous focused ultrasound or abdominal hysterectomy reported improvements in all Short Form-36 quality of life domains for both treatment groups, although scores at 6 months were better in patients treated by hysterectomy (significant for 5 of 8 domains with p values from 0.004 to 0.05). A case series of 40 patients reported a 40 percentile point improvement from baseline in quality-of-life score (0 to 100 scale) at 3-year follow-up (p<0.001).

A case series of 359 patients reported a significantly greater reduction from baseline in symptom severity score (0 to 100; higher scores worse) at 3 months in patients with a non-perfused volume (NPV) ratio greater than 20% versus those with an NPV ratio of 20% or less (31 points versus 24 points, p<0.001). The case series of 40 patients reported a 48 percentile point improvement from baseline in symptom severity score (0 to 100 scale) at 3-year follow-up (p<0.01).

Case series of 130 and 80 patients reported that 5% (7 out of 130) and 10% (8 out of 80) of patients respectively had a hysterectomy within 12 months.

A case series of 51 women who conceived after the procedure (54 pregnancies) reported that 41% (22 out of 54) of pregnancies resulted in deliveries; miscarriage occurred in 26% (14 out of 54) and 13% (7 out of 54) were electively terminated.

The Specialist Advisers listed key efficacy outcomes as quality of life, symptom improvement, avoidance of further surgery, and subsequent fertility.

Sciatic nerve palsy was reported in 1 of 109 patients (1%) treated by the procedure in the non-randomised comparative study of 192 patients. The case series of 80 patients reported mild temporary sciatica in 1 patient (1%).

The case series of 287 patients reported skin burns in 7% (10 out of 144) of patients treated in 2003–5 compared with 1% (2 out of 143) of patients treated in 2005–6 (p=0.04). A full-thickness burn in the lower abdomen was described in a case report (treated by excision and direct closure).

Spontaneous vaginal expulsion of treated fibroid tissue requiring hysteroscopic removal was documented in a case report.

Bowel perforation following treatment by the procedure was reported in 1 patient (total number treated unknown) in an adverse event report submitted to the US Food and Drug Administration (Manufacturer and User Facility Device Experience [MAUDE] database). Surgical management was required, confirming perforation in 3 bowel sites.

The Specialist Advisers considered a theoretical adverse event to be damage to the bladder.

The Committee was informed that many women wish to avoid more invasive interventions for symptomatic fibroids, even if this choice carries an increased chance of requiring further treatments. Some women choose this procedure because they wish to preserve their fertility: the lack of evidence on subsequent fertility underlies the recommendation in section 1.5.

The Committee noted that there is continuing evolution and development of the techniques used in this procedure.