Evaluation of a Hyperbaric Oxygen Therapy Intervention in Individuals with Fibromyalgia.

OBJECTIVE: To evaluate the feasibility and safety of hyperbaric oxygen therapy (HBOT) in patients with fibromyalgia (FM). DESIGN: A cohort study with a delayed treatment arm used as a comparator. SETTING: Hyperbaric Medicine Unit, Toronto General Hospital, Ontario, Canada. SUBJECTS: Eighteen patients diagnosed with FM according to the American College of Rheumatology and a score ≥60 on the Revised Fibromyalgia Impact Questionnaire. METHODS: Participants were randomized to receive immediate HBOT intervention (n = 9) or HBOT after a 12-week waiting period (n = 9). HBOT was delivered at 100% oxygen at 2.0 atmospheres per session, 5 days per week, for 8 weeks. Safety was evaluated by the frequency and severity of adverse effects reported by patients. Feasibility was assessed by recruitment, retention, and HBOT compliance rates. Both groups were assessed at baseline, after HBOT intervention, and at 3 months' follow-up. Validated assessment tools were used to evaluate pain, psychological variables, fatigue, and sleep quality. RESULTS: A total of 17 patients completed the study. One patient withdrew after randomization. HBOT-related adverse events included mild middle-ear barotrauma in three patients and new-onset myopia in four patients. The efficacy of HBOT was evident in most of the outcomes in both groups. This improvement was sustained at 3-month follow-up assessment. CONCLUSION: HBOT appears to be feasible and safe for individuals with FM. It is also associated with improved global functioning, reduced symptoms of anxiety and depression, and improved quality of sleep that was sustained at 3-month follow-up assessment.

An incoherent HIFU transducer for treatment of the medial branch nerve: Numerical study and in vivo validation.

BACKGROUND: Chronic back pain due to facet related degenerative changes affects 4-6 million patients a year in the United States. Patients refractory to conservative therapy may warrant targeted injections of steroids into the joint or percutaneous medial branch nerve denervation with radiofrequency ablation. We numerically tested a novel noninvasive high intensity focused ultrasound transducer to optimize nerve ablation near a bone-soft tissue interface. METHODS: A transducer with 4 elements operating in an incoherent mode was modeled numerically and tested pre-clinically under fluoroscopic guidance. After 6 lumbar medial branch nerve ablations were performed in 2 pigs, they were followed clinically for 1 week and then sacrificed for pathological evaluation. RESULTS: Simulations show that the acoustic spot size in water at 6 dB was 14mm axial x 1.6mm lateral and 52mm axial x 1.6mm lateral for coherent and incoherent modes, respectively. We measured the size of N = 6 lesions induced in vivo in a pig model and compared them to the size of the simulated thermal dose. The best match between the simulated and measured lesion size was found with a maximum absorption coefficient in the cortical bone adjusted to 30 dB/cm/MHz. This absorption was used to simulate clinical scenarios in humans to generate lesions with no potential side effects at 1000 and 1500 J. CONCLUSION: The elongated spot obtained with the incoherent mode facilitates the targeting during fluoroscopic-guided medial branch nerve ablation.