ObjectiveTo determine whether hypertonic saline (HS, 36% NaCl) injection prior to or during radiofrequency ablation (RFA) can increase the extent of thermally mediated coagulation in in-vivo rabbit liver tissue, and also to establish the ideal injection time in relation to RFA in order to maximize its effect on the extent of radiofrequency (RF)-induced coagulation.Materials and MethodsIn 26 rabbits, 43 RFA lesions were produced using a 17-gauge internally cooled electrode with a 1-cm active tip under ultrasound (US) guidance. Rabbits were assigned to one of three groups: Group A: RFA alone (n=8); Group B: RFA after the instillation of 1 mL HS (n=8); Group C: RFA after and during the instillation of 0.5 mL HS (n=10). RF energy (30 W) was applied for 3 minutes, and changes occurring in tissue impedance, current, power output, and the temperature of the electrode tip were automatically measured. After RFA, contrast-enhanced spiral CT was performed, and in each group the maximum diameters of the thermal lesions in gross specimens were compared. Technical success and the complications arising were evaluated by CT and on the basis of autopsy findings.ResultsAll procedures were technically successful. There were six procedure-related complications (6/26; 23%), including five localized perihepatic hematomas and one thermal injury to the stomach. With instillation of HS in group B rabbits, markedly decreased tissue impedance (73Ω ± 5) and increased current (704 mA ± 41) were noted, compared to RF ablation without saline infusion (116.3Ω ± 13, 308 mA ± 80). With instillation of the solution before RFA (group B), coagulation necrosis was greater (14.9 mm ± 3.8) than in rabbits not injected (group A: 11.5 mm ± 2.4; Group A vs. B: p < .05) and in those injected before and during RFA (group C: 12.5 mm ± 3.1; Group B vs. C: p > .05).ConclusionRFA using HS instillation can increase the volume of RFA-induced necrosis of the liver with a single application, thereby simplifying and accelerating the treatment of larger lesions. In addition, HS instillation before RFA more effectively achieves coagulation necrosis than HS instillation before and during RFA.
In contrast to the attachments to the pubis and rectum, there is little information on fetal development of the coccygeal attachment of the levator ani muscles. We find that at 9 weeks, the coccygeus muscle is a large muscle facing the piriformis or gluteus maximus and inserting onto the ischial spine, whereas the levator ani is restricted to the area near the pubis. By 12 weeks, the levator ani also obtains attachment to the ischial spine immediately ventral to the coccygeus muscle. The most superior part of the coccygeus muscle occupies a space at an angle between the pelvic splanchnic and pudendal nerves. Notably, medial to the coccygeus muscle, a third parasagittal muscle (previously termed the sacrococcygeus anterior) appears by 12 weeks, increases in mass by 18 weeks, and connects and mixes with the dorsal end of the levator ani by 18-20 weeks. Thus, the coccygeal attachment of the levator ani appears not to depend on the dorsal extension of the muscle itself but on fusion with the sacrococcygeus anterior. Therefore, the final levator sheet is formed medial (internal) to the coccygeus muscle and originates from two distinct anlage.
ObjectiveTo assess the feasibility and safety of CT-guided percutaneous transthoracic radiofrequency ablation (RFA) with saline infusion of pulmonary tissue in rabbits.Materials and MethodsTwenty-eight New Zealand White rabbits were divided into two groups: an RFA group (n=10) and a saline-enhanced RFA (SRFA) group (n=18). In the RFA group, percutaneous RFA of the lung was performed under CT guidance and using a 17-gauge internally cooled electrode. In the SRFA group, 1.5 ml of 0.9% saline was infused slowly through a 21-gauge, polyteflon-coated Chiba needle prior to and during RFA. Lesion size and the healing process were studied in rabbits sacrificed at times from the day following treatment to three weeks after, and any complications were noted.ResultsIn the SRFA group, the mean diameter (12.5 ± 1.6 mm) of acute RF lesions was greater than that of RFA lesions (8.5 ± 1.4 mm) (p < .05). The complications arising in 12 cases were pneumothorax (n=8), thermal injury to the chest wall (n=2), hemothorax (n=1), and lung abscess (n=1). Although procedure-related complications tended to occur more frequently in the SRFA group (55.6%) than in the RFA group (20%), the difference was not statistically significant (p = .11).ConclusionSaline-enhanced RFA of pulmonary tissue in rabbits produces more extensive coagulation necrosis than conventional RFA procedures, without adding substantial risk of serious complications.
This experimental study demonstrates the feasibility of RFA therapy for treating lung VX2 tumors in rabbits, although RFA for central tumors carries the potential for major complications, including large pneumothorax or obstructive pneumonia.
A report on an unusual combination of anomalies in the head of a female fetus. The authors examined whole body semiserial paraffin sections of a female fetus (155 mm CRL; ∼18 weeks of gestation), with a particular focus on the head region. Cranial autonomic ganglia, nasal olfactory cells, and the orbital muscle were investigated using immunohistochemistry for tyrosine hydroxylase, vasoactive intestinal peptide, calretinin, and smooth muscle actin expression. The surface gross anatomy of the fetus appeared normal. The left eyeball lacked a lens (the eyeballs were otherwise normal). The orbital muscle was very thick and located in the anterolateral side of the extraocular muscles. Conversely, the extraocular muscles made a cluster in the superoposterior side of the orbit. The infratemporal fossa was small due to the bulky, transversely extended lateral pterygoid process in contrast to the small coronoid process of the mandible. The bilateral mandibular bases overlapped at the midline symphysis. The thin orbitosphenoid and thick alisphenoid provided an almost flat, anterior cranial base. Nasal olfactory cells and cranial autonomic ganglia appeared to be normal. No major anomaly was observed in the brain. Because of the changes in topographical anatomy, the orbital muscle probably lost its normal bony attachment and appeared to push the extraocular muscles superoposteriorly. A gene function redundancy rather than mutation may explain the present restricted anomalies in the mandible and pterygoid process.
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