The cryo-needle: a new tool for histological biopsies. A feasibility study.

PURPOSE: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure for intrathoracic lymph node biopsies. The newly developed cryo-needle operates in a similar way to the EBUS-TBNA but is able to obtain specimens for histological evaluation. The purpose of this animal study was to evaluate the feasibility, effect, and safety of the cryo-needle biopsies. METHODS: Four EBUS-guided cryo-needle biopsies were obtained from a mediastinal lymph node of a healthy pig. In an open surgery approach, cryo-needle biopsies using activation times of 1, 2, and 3 s (A1/A2/A3) and needle biopsies using a 21-gauge EBUS-TBNA needle were obtained from mesenteric lymph nodes. Cryo-needle biopsies A2 were performed with (A2+) and without (A2-) an oversheath. The size, weight, percentage of lymphatic tissue and artefact-free area of each cryobiopsy were evaluated. Smears were made with the TBNA-needle aspirates to determine the number of lymphocytes per high-power field (HPF). The bleeding duration was measured. RESULTS: We successfully obtained EBUS-guided cryo-needle biopsies. The area and weight of the biopsies A3 and A2+ were significantly larger compared with A1 (1.7 ± 0.8 and 1.4 ± 0.3 vs. 0.9 ± 0.4 mm(2); 5.2 ± 2.4 and 3.4 ± 1.8 vs. 1.5 ± 0.7 mg). The percentage of lymphatic tissue of the cryobiopsies was 90 ± 25 and 98 % of samples were artefact-free. The number of lymphocytes/HPF of TBNA-needle smears was 128 ± 54.3. There was no difference in bleeding duration between the techniques. CONCLUSIONS: The cryo-needle yields large histological specimens of high quality.

Experimental study on biopsy sampling using new flexible cryoprobes: influence of activation time, probe size, tissue consistency, and contact pressure of the probe on the size of the biopsy specimen.

Cryoextraction is a procedure for recanalization of obstructed airways caused by exophytic growing tumors. Biopsy samples obtained with this method can be used for histological diagnosis. The objective of this study was to evaluate the parameters influencing the size of cryobiopsies in an in vitro animal model. New flexible cryoprobes with different diameters were used to extract biopsies from lung tissue. These biopsies were compared with forceps biopsy (gold standard) in terms of the biopsy size. Tissue dependency of the biopsy size was analyzed by comparing biopsies taken from the lung, the liver, and gastric mucosa. The effect of contact pressure exerted by the tip of the cryoprobe on the tissue was analyzed on liver tissue separately. Biopsy size was estimated by measuring the weight and the diameter. Weight and diameter of cryobiopsies correlated positively with longer activation times and larger diameters of the cryoprobe. The weight of the biopsies was tissue dependent: lung < liver < stomach. Only little tissue dependency was found for the biopsy diameter. The biopsy size increased when the probe was pressed on the tissue during cooling. Cryobiopsies can be taken from different tissue types with flexible cryoprobes. The size of the samples depends on tissue type, probe diameter, application time, and pressure exerted by the probe on the tissue. Even the cryoprobe with the smallest diameter can provide larger biopsies than a forceps biopsy in lung. It can be expected that the same parameters influence the sample size of biopsies in vivo.

An individually adjustable oral appliance vs continuous positive airway pressure in mild-to-moderate obstructive sleep apnea syndrome.

BACKGROUND: For the treatment of nonsevere obstructive sleep apnea syndrome (OSAS), mandibular advancement devices (MADs) are employed as an alternative to nasal continuous positive airway pressure (CPAP) therapy. However, very few specific data on the effectiveness of MADs in this group of patients are available. We therefore compared an individually adjustable intraoral sleep apnea device (ISAD) that permits movements of the lower jaw in three dimensions, with CPAP in the treatment of patients with an apnea/hypopnea index (AHI) < or = 30/h. METHODS: In a randomized crossover study, 16 men and 4 women (mean +/- SD age, 56.5 +/- 10.2 years; body mass index, 31.2 +/- 6.4; AHI, 17.5 +/- 7.7/h) were treated for 6 weeks with each modality. RESULTS: In the initial phase, a significant improvement in AHI (baseline, 17.5 +/- 7.7/h; ISAD, 10.5 +/- 7.5/h [p < 0.05]; CPAP, 3.5 +/- 2.9/h [p < 0.01]) and in breathing-related arousals (baseline, 8.9 +/- 6.1/h; ISAD, 3.7 +/- 3.3/h [p < 0.01]; CPAP, 1.4 +/- 1.6/h [p < 0.01]) was achieved with both modalities. Considering all 20 subjects, after 6 weeks of treatment, normalization of the respiratory parameters was seen only with CPAP. However, 30% of the patients had a lasting reduction in AHI to < 10/h with the ISAD also. The patients considered the ISAD to be easier to use (scale of 1 to 6: ISAD, 1.8 +/- 1.1; CPAP, 3.1 +/- 1.5 [p < 0.05]), and indicated greater utilization of the device in comparison with CPAP. CONCLUSION: Even in patients with mild-to-moderate OSAS, CPAP is the more effective long-term treatment modality. In the individual case, the better compliance seen with the ISAD may be advantageous.