Zhanwen Wang

Effects of low-intensity pulsed ultrasound on new trabecular bone during bone-tendon junction healing in a rabbit model: a synchrotron radiation micro-CT study.

This study was designed to evaluate the effects of low-intensity pulsed ultrasound on bone regeneration during the bone–tendon junction healing process and to explore the application of synchrotron radiation micro computed tomography in three dimensional visualization of the bone–tendon junction to evaluate the microarchitecture of new trabecular bone. Twenty four mature New Zealand rabbits underwent partial patellectomy to establish a bone–tendon junction injury model at the patella–patellar tendon complex. Animals were then divided into low-intensity pulsed ultrasound treatment (20 min/day, 7 times/week) and placebo control groups, and were euthanized at week 8 and 16 postoperatively (n = 6 for each group and time point). The patella–patellar tendon specimens were harvested for radiographic, histological and synchrotron radiation micro computed tomography detection. The area of the newly formed bone in the ultrasound group was significantly greater than that of control group at postoperative week 8 and 16. The high resolution three dimensional visualization images of the bone–tendon junction were acquired by synchrotron radiation micro computed tomography. Low-intensity pulsed ultrasound treatment promoted dense and irregular woven bone formation at week 8 with greater bone volume fraction, number and thickness of new trabecular bone but with lower separation. At week 16, ultrasound group specimens contained mature lamellar bone with higher bone volume fraction and thicker trabeculae than that of control group; however, there was no significant difference in separation and number of the new trabecular bone. This study confirms that low-intensity pulsed ultrasound treatment is able to promot bone formation and remodeling of new trabecular bone during the bone–tendon junction healing process in a rabbit model, and the synchrotron radiation micro computed tomography could be applied for three dimensional visualization to quantitatively evaluate the microarchitecture of new bone in bone–tendon junction.

Initiation Timing of Low-Intensity Pulsed Ultrasound Stimulation for Tendon-Bone Healing in a Rabbit Model:

Background: Low-intensity pulsed ultrasound stimulation (LIPUS) has been proven to be a beneficial biophysical therapy for tendon-bone (T-B) healing. However, the optimal time to initiate LIPUS treatment has not been determined yet. LIPUS initiated at different stages of the inflammatory phase may profoundly affect T-B healing. Purpose: An established rabbit model was used to preliminarily investigate the effect of LIPUS initiation timing on T-B healing. Study Design: Controlled laboratory study. Methods: A total of 112 mature rabbits that underwent partial patellectomy were randomly assigned to 4 groups: daily mock sonication (control group) and daily ultrasonication started immediately postoperatively (immediate group), on postoperative day 7 (7-day delayed group), or on postoperative day 14 (14-day delayed group). Peripheral leukocyte counts at the inflammatory phase were used to assess postoperative inflammation. The rabbits were sacrificed at 8 or 16 weeks postoperatively for microarchitectural, histological, and mechanical evaluations of the patella–patellar tendon (PPT) junction. Results: The biomechanical properties of the PPT junction were significantly improved in the LIPUS-treated groups. Significantly higher ultimate strength and stiffness were seen in the 7-day delayed group compared with the other groups at 8 weeks postoperatively (P < .05 for all). Newly formed bone expansion from the remaining patella in the ultrasonic treatment groups was significantly increased and remodeled compared with the control group. Micro–computed tomography analysis showed that the 7-day delayed group had significantly more bone volume and bone mineral content at the interface as compared with the other groups at 8 weeks postoperatively (P < .05 for all). Histologically, the ultrasonic treatment groups exhibited a significantly better PPT junction, as shown by more formation and remodeling of the fibrocartilage layer and newly formed bone. Additionally, peripheral leukocyte counts displayed a significant increase from postoperative day 1 to day 3 in the immediate group as compared with the other groups. Furthermore, postoperative hydrarthrosis was more likely in the immediate group. Conclusion: LIPUS started at postoperative day 7 had a more prominent effect on T-B healing compared with the other treatment regimens in this study. Clinical Relevance: The findings of the study may help optimize the initiation timing of LIPUS for T-B healing.

Three-dimensional computed tomograph angiography and neuroendoscope assisted microsurgery for intracranial aneurysm

OBJECTIVE To determine the role of 3-dimensional computed tomograph angiography (3D-CTA) and neuroendoscope in intracranial aneurysm, and to analyze its benefits. METHODS A total of 38 patients with intracranial aneurysm were confirmed by operation. All the patients were examined by 3D-CTA before the operation and surgical simulation was conducted to ensure the location of aneurysm and its relationship with parent aneurysm artery. Endoscopy was used as an adjunct before and after the microsurgical treatment to observe the neck anatomic features and perforating branches and to verify the optimal clipping position. RESULTS Pre-operative 3D-CTA clearly displayed the aneurysm and their relation with the parent aneurysm artery, the aneurysm, the periphery vessel, and bony structures, according to demonstration during the operation. Endoscope clearly showed the anatomy around aneurysm, especially the perforating branches. Postoperative 3D-CTA showed satisfactory aneurysm clipping. CONCLUSION Simulation surgery of 3D-CTA is helpful in finding and exposing aneurysm. Neuroendoscope is very useful for protecting deep blood vessels. Combination of the two can increase the operation success ratio and reduce postoperative complications.