Surgical technique for a cystic-type metastatic brain tumor: transformation to a solid-type tumor using hydrofiber dressing

Background

Many metastatic brain tumors have a distinct border with normal brain tissue, which facilitates tumor removal. However, residual tumor tissue may be present after surgery when metastatic brain tumors are of cystic type. We have developed a method using hydrofiber dressing to transform cystic-type into solid-type tumors.

Methods

Hydrofiber dressing is a sodium carboxymethylcellulose hydrocolloid polymer with high fluid-absorptive capacity. This material was originally used as a dressing for exudative wounds. Hydrofiber dressing was used for 8 patients with cystic-type metastatic brain tumor. Tumor removal was performed after hydrofiber dressing was inserted into the cyst cavity to transform the tumor into a solid-type tumor.

Results

Transformation of cystic-type metastatic brain tumors into smaller solid-type tumors using hydrofiber dressing facilitated en bloc resection of tumor. The dressing also absorbed residual cyst fluid and was thus also effective in preventing intraoperative dissemination of tumor cells. This approach enabled ideal en bloc resection in all patients. There were no adverse events.

Conclusions

These findings suggest hydrofiber dressing may be useful in surgery for cystic-type metastatic brain tumors.     

Quantitative analysis of motor neurons of the levator ani muscle in fetal rats with spina bifida occulta

Background

With the combination of microsurgery and microinjection techniques, we investigated the development of motor neurons in the spinal cord of fetal rats with spina bifida occulta by injecting the retrograde trace FG into the levator ani muscle.

Methods

The fetal rats were divided into 3 groups. On the day 9 of gestation, 6 mature Wistar rats (weighing 250-300 g) in the control group (group 1) were subcutaneously injected with 0.5 mL of normal saline at their hind limbs at 9:00 am and 4:00 pm. At these 2 time points, 15 rats in the treatment group (group 2 and group 3) were subcutaneously injected with 20% sodium valproate solution (400 mg/kg of body weight) at their hind limbs, too. On the day 20 of gestation, pregnant rats were anesthetized with 10% chloral hydrate (300 mg/kg of body weight) intraperitoneally, and then fetal microsurgery and microinjection were performed to expose the levator ani muscle, whereas 5% FG was administered with microinjector. Twenty-four hours later, transcardial perfusion of 4% paraformaldehyde in phosphate-buffered saline (PBS) was given to the operated fetus. After the spine sample was stained with Alcian blue GX, the image of stained spine was measured using a computer system for the distance of the 2 cartilaginous ends of the vertebra arch. Then, the lumbosacral spinal cord was cryopreserved in 20% sucrose in PBS for a later serial transverse cryosection after 24 hours. The FG-labeled motor neurons were visualized with a wide-band ultraviolet-fluorescent filter, and the number of the FG-labeled motor neurons was recorded. Nine fetal rats survived in group 1. Eighteen fetal rats survived in the treatment group, including 7 (with no malformation) of 18 fetuses in group 2 and 11 fetuses with spina bifida occulta in group 3.

Results

The FG-labeled motor neurons in the ventral horn of normal spinal cord clustered at the dorsolateral and dorsomedial corner of the ventral horn. The FG-labeled motor neurons in the ventral horn of deformed spinal cord were less than that of normal spinal cord, and the motor neurons were scattered around the space between the dorsomedial and dorsolateral corners. The number of FG-labeled motor neurons was 244 ± 41 in group 3, 426 ± 36 in group 1, and 397 ± 20 in group 2. The data were stastistically significant if P < .05.

Conclusion

The motor neurons that innervate the levator ani muscle in fetal rats with spina bifida occulta are fewer than the normal fetal rats, and they are arranged in abnormal distribution.     

Model to predict if a vasoepididymostomy will be required for vasectomy reversal

PURPOSE: We devised a model to predict, preoperatively, the need for a vasoepididymostomy (VE) when performing a vasectomy reversal. Urologists could use it to identify those patients who need a referral to an experienced VE surgeon. MATERIALS AND METHODS: We performed a retrospective review of 483 patients who underwent vasectomy reversal by a single surgeon (AJT) including 393 vasovasostomies and 90 vasoepididymostomies. Selection was based on chart availability. Established criteria were used in deciding the type of reversal (eg gross appearance and microscopic examination of vasal fluid). Type of reversal, patient age and time since vasectomy were recorded. Univariate analysis revealed that patient age (p <0.001) and time since vasectomy (p <0.001) were significant predictors of reversal type. On multivariate logistic regression analysis, time since vasectomy (p <0.001) was the only significant independent predictor. We designed a linear regression algorithm based on time since vasectomy and patient age to predict if a VE would be performed. The model was designed using 433 patients and then tested on a separate randomly selected 50 patient group. The model was designed to be 100% sensitive in detecting patients requiring VE. RESULTS: In the test group the model was 100% sensitive in predicting VE with a specificity of 58.8%. The area under the ROC curves for the design and test groups was 0.8. Palm (PalmSource Inc., Sunnyvale, California) and Windows (Microsoft Corporation, Redmond, Washington) versions are available as free shareware from www.uroengineering.com. CONCLUSIONS: The model is 100% sensitivity in detecting those patients who may require a VE during vasectomy reversal (specificity of 58.8%). It may allow urologists to preoperatively identify these patients.