| BackgroundBenign Prostatic Hyperplasia is a common urological disease, often occurs in middle-aged men, which can lead these men suffer from voiding dysfunction, and this is the most common reason of voiding dysfunction. The main performance of BPH on histological is the hyperplasia of prostate gland and stromal, prostatic enlargement in anatomy, the bladder outlet obstruction on urodynamic and lower urinary tract symptoms. The BPH’s occurring has a relationship with age and it has increase trends of morbidity as with age. An autopsy report of institute of urology in Peking University has showed that the morbidity of benign prostatic hyperplasia was 13.2% in the 41-50 years old,51-60 years old was 20%,50% for the 61-70 years old, and the percent can be reached 57.1% when you are 71-80 years old and 83.3% on 80 years old. Simultaneously, it causes difficulty voiding symptoms also increased with age. BPH can be cause a variety of complications as the disease progresses, such as recurrent urinary retention and hematuria, urinary tract infection, bladder stones, hernia and secondary upper tract seeper. In addition, in some severe case, the disease can even lead to chronic renal failure, which seriously troubled the elderly patient’s life.With the improvement of the national economic development and health conditions, people’s average life expectancy has been increasing, and our country is becoming an aging society. Meanwhile, owning to the implementation of family planning, our birth rate is declining, but the proportion of the elderly is increasing. As of 2014, China’s aged 60 and the older has a population of 212 million, accounting for 15.5% of the total population, a figure equivalent to the total number of the population of Germany, France and the UK. It can easy predict that the morbidity and the patient’s number of BPH will be increased in the future. The whole society will pay for higher medical costs in the treatment of BPH, consume more health care resources. This will be a challenge to the clinical urology and national medical and health services.It is still lack of effective means of treatment targeting for BPH etiology, because the etiology and pathogenesis of BPH is not entirely clear at present. The current main treatment of BPH is routine observation, drug therapy and surgery. Routine observation only suit to the patients who have mild urinary tract symptoms and has a good quality of life. Nowadays, the most commonly used drugs for treating BPH is a-blockers and 5a-reductase inhibitors, which have an exact efficacy of BPH. However, they have a disadvantage of long time medication and work slowly. And with the progress of the disease, many patients eventually require surgery to relieve lower urinary tract symptoms. Generally believed that lower urinary tract symptoms can seriously affect the quality of life and also associated with severe complications. As a result, as long as the physical condition of the patient permits, the surgery treatment should be done. The surgical treatment has undergone open prostatectomy, transurethral resection of the prostate, and the current minimally invasive laser surgery. Because of the trauma, bleeding, complications, and length of hospital stay, the open prostatectomy surgical almost abandon now. Transurethral resection is inserted the resectoscope through the urethra, then removing the prostate hyperplasia through electricity cut ring under direct vision. Compared with the traditional open prostatectomy surgery, this method does not need to establish another channel for surgery, what’s more, the patient less pain, less bleeding, faster recovery, shorter hospital stay, and postoperative voiding symptoms improve quickly. Nowadays, almost all of the BPH can be treated by TURP surgery, therefore, the TURP surgery was thought as the "gold standard" on treating BPH to all the world urologists. But there still have the complications of bleeding and prostate syndrome, especially when the prostate volume become more larger, as well as the longer operative time, the intraoperative and postoperative complication rate will be more higher, which proportion can up to 24.9%. Meanwhile, TURP has the problem of insufficient glandular excision and higher long-term recurrence rate. People have been looking for better surgical to change this situation. In recent years, with the rapid development of laser technology, new types of surgical laser technology emerged, and most of them were used at the urology fields, especially the treatment of BPH. Current clinical commonly used laser include:green laser, holmium laser, thulium laser and 980nm diode laser technology based.ObjectiveIn this study, animal model was built for detecting the efficiency of DL-C type semiconductor laser, and assessing the potential effectiveness and safety of this equipment in clinical treatment of prostate.Materials and Methods1. The materials1.1 experimental animals2 adult male beagles with normal vital signs (weight 11.6±2.1 kg) and 8 in vitro porcine kidneys (weight 145.8±23.2g) was provided by the laboratory animal center, southern medical university.1.2 experimental equipment and drugsDomestic DL-C type semiconductor laser therapeutic machine, optical fiber, ureteroscope (for laser use),0.9% saline, stupefacient,8-10F urinary catheter, normal bladder irrigator, blood bag, formaldehyde solution, the routine operation instrument set, heparin, plastic containers, etc.The Methods1. In vitro experimental groupTo evaluate the tissue ablation efficiency and hemostatic properties of the DL-C type semiconductor laser, the porcine kidneys were harvested from live pigs, and then were dealed with this equipment in different output power.The porcine kidneys were harvested from live pigs (a certain length of renal artery and vein should to be kept), and then the kidneys were immediately lavaged by saline through renal artery to remove blood and to avoid thrombogenesis. Keep the kidneys at 4℃ environment when the outflow of renal vein was clear and recycle the porcine autologous blood for in vitro porcine kidney perfusion. These boold was heparinization with heparin 8000IU/L and kept at 4℃ environment.The experiment should began within 4 hours after the kidneys was harvested. All experiments were performed in plastic container contain 37℃ 0.9% sodium chloride solution. Before the experiment, the kidneys were soak in 37℃ 0.9% sodium chloride solution for 30 min.Ablation speed:the laser treatment by DL-C type semiconductor laser was performed on the in vitro porcine kidney’s independent surface area in continuous mode with 30,50,80,100,110,120,140,150,140 w power, respectively and in pulse mode with 100w power (on 0.1 s; off 0.1,0.05,0.01 s). Time and the operation area was set 10 minutes and 3×3 cm2, respectively.Pull out the urinary catheter in renal artery, ligation the blood vessels. Adopt the continuous pulse output mode in non-contact mode, with different power (0-200w) to deal with in vitro porcine kidney’s independent surface area by laser treatment. Time and the operation area was set 10 minutes and 3x3 cm2, respectively. Record in vitro porcine kidney’s weight and ablation depth before and after the experiment, the weight difference before and after the experiment is the weight of the ablation tissue. Repeat the operation above with different power (0-200w), and record the in vitro porcine kidney weight difference before and after every experiment.The in vitro porcine kidney tissue was dealed with laser with different power(1-200W).Time and the operation area was set 1 minute and lxlcm2, respectively. Observe the degree of scab during experimental process.The tissue section of porcine kidney was used for TTC and HE staining. Observe these tissue section under optical microscope and measure depth of solidified layer (CZ), transition layer (TZ), and normal tissue layer (NLZ) (mm) respectively with a standard compasses.2. In vivo experimental groupThe DL-C type semiconductor laser was used to simulate the human body light selective vaporization resection of prostate surgery system, vaporization resection to the bladder neck distalis. Semiconductor laser vaporization resection of the prostate was done under the established power and energy. The animals were sacrificed immediately when the experiment was completed, and the pathological tissue examination was done by the naked eye and optical microscope.Anesthesia:all the beagles were given propofol, buprenorphine and cefazolin, and were given buprenorphine, ibuprofen and ammonia benzyl cephalosporin when placing a urinary catheter postoperatively. After anesthesia, the beagle was put in the supine position with fixed limbs, and lower jaw and tongue tied together, avoiding breathing suffocate during the surgery. At the same time, ECG monitor was connected with the dog, for monitoring the change of vital signs such as heart rate, breathing, blood pressure and blood oxygen saturation of experimental animal, intraoperatively. The state of anesthesia was maintained by levulinic oxazine and halothane.The Operation Procedure:The retrograde laser vaporization of prostate was performed on the experimental group. As a result of the existence of the penis bone, an incision as close as possible to ball urethra should be done in the perineum. do a longitudinal cut when the ball urethra was exposed. Expand the urethra, insert the 8F ureteroscope and place it in the prostatic urethra. Place the non-contact lateral shoot laser optical fiber through the work channel. Put the laser fiber to the position that the distance to the prostate tissue surface is within 2-3 mm and rotate the laser fiber for vaporizing the prostate tissue. Wash with saline, using different power to different dog. Simulating human transurethral vaporization resection of the prostate, the operation area is from the verumontanum to the bladder neck distalis and record operation time T (min). To assess whether the tissue ablation is enough and to select a time to stop the operation, an observation of the operation cavity size and symmetry was done. A postoperative washing is not needed. Insert the urinary catheter into the bladder and fix it on the foreskin, close perineum incision layer-by-layer. Remove the urinary catheter Postoperatively.Sacrifice the beagle by painless death way, remove the prostate tissue immediately, measuring appearance, slitting andtake pictures. Get prostate tissue in vertical axis and coronal axis of the operative cavity. The prostate tissue and tissue slides was used for TTC and HE staining, and were observed under optical microscope after HE staining. Solidified layer (CZ), transition layer (TZ), and normal tissue layer (NLZ) (mm) depth were measured with a standard compasses.ResultsIn vitro, the change of the ablation speed is not obvious when at low power (80 w), but faster when at the high power (80-200w), and the more power the ablation speed is more faster, the solidification speed is also accelerated. Contrast the ablation speed of different patterns at the power of 100w, it was found that the continuous mode is faster than pulse mode. In pulse mode, the shorter the time interval between laser output, the ablation speed is faster, slower conversely. In vivo, the vital signs of the experimental animals are normal, the ablation speed is fast and coagulation hemostasis effect is obvious. Postoperative pathologic examination of dog’s prostate tissue showed that the tissue coagulation layer is 1.4-1.7mm in depth, transition layer is 0.4-0.5 mm in thickness, solidified layer thickness is moderate.ConclusionUnder high-power, the DL-C type semiconductor laser has a fast tissue ablation speed, and with the power improved, it can rapidly improve the ablation speed. This equipment can offer a quickly vaporization, cutting, tissue solidification, hemostasis and small tissue thermal damage degree. DL-C type semiconductor laser therapeutic machine works reliably, performances stably, operate easily. For vaporization, cutting and coagulation of prostate tissue, it has a significant characteristics of high efficiency, safety, and simply use and so on. |
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