Effect of upright position on tonsillar level in adolescent idiopathic scoliosis.

PURPOSE: The aim of this study was to investigate the effect of an upright position on cerebellar tonsillar level in patients with adolescent idiopathic scoliosis (AIS). METHODS: Twenty-five patients with clinically diagnosed AIS and 18 normal controls were examined in both supine and upright positions using 0.25T MRI. The position of the inferior cerebellar tonsil tip relative to a reference line connecting the basion to the opisthion (BO line) was measured in millimetres. RESULTS: None of the 18 normal control subjects had cerebellar tonsillar descent below the BO line in either supine or the upright position. Forty-eight percent of AIS patients had tonsillar descent in the upright position, compared to 28 % in the supine position. In the upright position, cerebellar tonsillar position was lower in AIS patients than in normal subjects (mean -0.7 ± 1.5 vs. +2.1 ± 1.7, p < 0.00001). AIS patients also had a large degree of tonsillar excursion between upright and supine positions compared to normal subjects (mean -1.9 ± 2.3 vs. -0.1 ± 0.2, p < 0.00001). CONCLUSIONS: When considering the theoretical likelihood that a low tonsillar position may affect spinal cord function, one should bear in mind that tonsillar descent in AIS is significantly greater in the upright position. KEY POINTS: • AIS patients exhibited greater cerebellar tonsillar descent in upright than supine position. • Cerebellar tonsillar position was lower in AIS patients than normal subjects. • AIS patients exhibited greater tonsillar excursion between supine and upright positions.

Diagnostic capability of low- versus high-field magnetic resonance imaging for lumbar degenerative disease.

STUDY DESIGN: Cohort study. OBJECTIVE: To investigate the diagnostic capability of low-field magnetic resonance imaging (MRI) compared with high-field MRI for degenerative disease of the lumbar spine. SUMMARY OF BACKGROUND DATA: Low-field MRI has several advantages over high-field magnetic resonance systems (easier installation, lower purchase, and maintenance cost). The diagnostic capability of low-field MRI for degenerative disease of the lumbar spine has not been compared with that of high-field MRI. METHODS: Hundred patients (mean age: 56.3 yr, range: 32-80; F:M = 59:41) with neurogenic claudication or sciatica were studied. All patients underwent MRI of the lumbar spine on both low-field (0.25T) and high-field (1.5T or 3.0T) magnetic resonance systems. Intervertebral disc herniation, central canal, lateral recess, and exit foraminal stenosis as well as nerve root compression at L3-L4, L4-L5, and L5-S1 were evaluated by 2 radiologists for both low- and high-field systems using established reliable grading systems. RESULTS: There was excellent agreement between low- and high- field MRI with regard to grading the presence and severity of disc herniation (r = 0.92-0.94; P < 0.05), central canal stenosis (r = 0.89-0.91; P < 0.05), lateral recess stenosis (r = 0.81-0.87; P < 0.05), and exit foramen stenosis (r = 0.81-0.89; P < 0.05). Descending or exiting nerve root compression occurred in 52% of patients at L3-L4, L4-L5, or L5-S1 levels, with good agreement between low-field and high-field MRI (r = 0.71-0.76; P < 0.05) for nerve root compression. CONCLUSION: Excellent reliability between low- and high- field MRI was found for most features of lumbar disc degeneration, with good agreement for nerve root compression. 0.25T MRI was more susceptible to motion artifact, probably due to longer scanning time. LEVEL OF EVIDENCE: 3.

Safety and efficacy of sonographically guided high-intensity focused ultrasound for symptomatic uterine fibroids: preliminary study of a modified protocol.

OBJECTIVES: We aimed to assess the safety and efficacy of sonographically guided high-intensity focused ultrasound for treating patients with symptomatic uterine fibroids using a modified protocol. METHODS: This work was part of an ongoing prospective phase 1 study. Twenty patients with 22 symptomatic fibroids were treated with sonographically guided high-intensity focused ultrasound under no anesthesia. The modified protocol consisted of repeated and shortened (<25 minutes) treatment sessions of high-input acoustic intensity (1000-1500 W/cm(2)) and intensified sonication pulses (1500-2000) at each spot. The primary end points were periprocedural complications. The secondary end points were symptomatic improvement and radiologic evidence of treatment responses, including the degree of fibroid infarction and volume shrinkage 3 months after treatment. Symptomatic improvement was assessed by a pain score, a pictorial chart menstrual score, the Urogenital Distress Inventory short form, and the Incontinence Impact Questionnaire short form. The degree of fibroid infarction was assessed by the nonperfused ratio on contrast-enhanced magnetic resonance imaging, defined as the ratio of the nonperfused fibroid volume to the total fibroid volume. RESULTS: Nineteen patients tolerated the treatment well, with no major adverse events. One patient who received treatment for a fibroid located within 6 cm from the skin had third-degree skin burns at 2 sites of 1 cm in diameter. Fibroid-related abdominal pain, pictorial chart, Urogenital Distress Inventory, and Incontinence Impact Questionnaire scores were significantly improved (P < .05). The median nonperfused ratio at 3 months was 20% (95% confidence interval, 5%-32.5%). Median volume shrinkage at 3 months was 17.2% (95% confidence interval, 4.3%-26.6%). CONCLUSIONS: Sonographically guided high-intensity focused ultrasound using a modified protocol may be safe and effective for symptomatic uterine fibroids in selected patients to avoid skin burns.

Pathological fracture as the presenting feature in pediatric osteosarcoma.

BACKGROUND: Pathological fracture is an uncommon presentation in patients with long bone osteosarcoma. PROCEDURES: We retrospectively reviewed the database of all patients with histologically proven osteosarcoma under the age of 18 years from 1991 to 2011 in a tertiary pediatric oncology referral center. Five patients with pathological fractures as the first presentation of osteosarcoma were identified. The treatment strategies and complications were evaluated. Ten sex-, age-, and site- matched osteosarcoma patients without pathological fracture were selected as controls. The incidence of distant metastases and outcome, including local recurrence and survival, were compared between the index (with pathological fracture) and the control (without pathological fracture) groups. RESULTS: In the index group, all five patients were boys and the mean age of onset was 13.1 years (range 9.2-14.9). Three patients (60%, 3/5) received amputation and two (40%) had wide local excision of the tumor. Pathological fracture group showed higher rate of lung (60% vs. 10%, P = 0.04) and bone (60% vs. 10%, P = 0.04) metastases at presentation, and shorter overall 5-year survival (P = 0.04) than the control group. There was no significant difference of local recurrence (20%, P = 1.00) between these two groups regardless of the type of operation. CONCLUSION: Osteosarcoma complicated by pathological fracture as first presentation had higher incidence of lung and bone metastases at presentation and worse survival rate when compared with patients without pathological fracture.