Comparison of difficulty in stair ascent and descent after total knee replacement.

[Purpose] Although many studies have shown that patients have difficulty in climbing or descending stairs after undergoing total knee replacement, no study so far has compared the difficulty of stair ascent and descent based on objective indicators. This study compared stair ascending and descending processes based on three indicators and clarified which was more difficult. [Participants and Methods] We defined 1) movement method, 2) the necessity for handrail use, and 3) speed as objective indicators. Seventy-eight patients who underwent total knee replacement participated in this study. Three months after the surgery, we examined 1) whether the patients could ascend or descend in a step-over-step or step-by-step manner, 2) whether the patients required handrail support, and measured 3) the time required to ascend and descend for four steps. [Results] The step-by-step movement and handrail requirement rates associated with stair descent were higher than the corresponding rates associated with stair ascent. In addition, the time required for stair descent was greater than that required for ascent. [Conclusion] We found that stair descent was more challenging than stair ascent in terms of all three objective indices: movement method, handrail use, and speed. The results indicate that rehabilitation after total knee replacement should focus more on stair descent than on stair ascent.

Improvement in Gait Speed Affects Short-term Improvement in Activities of Daily Living in Patients with Moderate and Severe Knee Osteoarthritis.

Objectives: It is unclear whether improvements in knee pain or physical function lead to improvements in activities of daily living (ADL) and quality of life (QOL) in patients with moderate to severe knee osteoarthritis (KOA). This study aimed to investigate whether improvements in knee pain and physical function, achieved through exercise therapy, lead to improvements in ADL and QOL in patients with moderate to severe KOA. Methods: This case-control study included 18 patients with KOA. We evaluated knee range of motion, knee extension muscle strength (KEM), gait speed, knee pain, Knee Injury and Osteoarthritis Outcome Score (KOOS)-ADL, and KOOS-QOL at the first visit and after 3 months of exercise therapy. Patients were classified into the ADL and QOL improvement or no-improvement groups. Statistical analysis used split factorial analysis of variance with time and group as the main effects. When interactions were observed, post-hoc analysis was performed with two-sample t-tests. Results: For ADL improvement, the improvements in KEM of the affected side and gait speed were statistically significant. At 3 months, the gait speed of the improvement group was significantly higher than that of the no-improvement group. For QOL improvement, there was no significant interaction for any of the factors evaluated. Conclusions: No factor showed significant contribution to improved QOL in patients with moderate to severe KOA. However, increased gait speed may improve ADL and contribute to the development of efficient rehabilitation programs for patients with moderate to severe KOA.

Examination of the Impact of Strength and Velocity of the Knee and Ankle on Gait Speed in Community-Dwelling Older Adults.

The muscle strength of the knee extension and plantarflexion plays a crucial role in determining gait speed. Recent studies have shown that no-load angular velocity of the lower limb joints is essential for determining gait speed. However, no reports have compared the extent to which lower limb functions, such as knee extension strength, knee extension velocity, plantarflexion strength, and plantarflexion velocity, impact gait speed in a single study. Therefore, this study aimed to examine the relative importance of maximum strength and no-load angular velocity on gait speed. Overall, 164 community-dwelling older adults (72.9 ± 5.0 years) participated in this study. We measured the gait speed and lower limb function (the strength and velocity of knee extension and plantarflexion). Strength was measured with a hand-held dynamometer, and velocity with a gyroscope. A multiple regression analysis was performed with gait speed as the dependent variable and age, sex, and lower-limb function as independent variables. Plantarflexion velocity (ß = 0.25) and plantarflexion strength (ß = 0.21) were noted to be significant predictors of gait speed. These findings indicate that no-load plantarflexion velocity is more important than the strength of plantarflexion and knee extensions as a determinant of gait speed, suggesting that improvement in plantarflexion velocity may increase gait speed.

The combination of silver-containing hydroxyapatite coating and vancomycin has a synergistic antibacterial effect on methicillin-resistant Staphylococcus aureus biofilm formation.

AIMS: Biofilm formation is intrinsic to prosthetic joint infection (PJI). In the current study, we evaluated the effects of silver-containing hydroxyapatite (Ag-HA) coating and vancomycin (VCM) on methicillin-resistant Staphylococcus aureus (MRSA) biofilm formation. METHODS: Pure titanium discs (Ti discs), Ti discs coated with HA (HA discs), and 3% Ag-HA discs developed using a thermal spraying were inoculated with MRSA suspensions containing a mean in vitro 4.3 (SD 0.8) x 106 or 43.0 (SD 8.4) x 105 colony-forming units (CFUs). Immediately after MRSA inoculation, sterile phosphate-buffered saline or VCM (20 µg/ml) was added, and the discs were incubated for 24 hours at 37°C. Viable cell counting, 3D confocal laser scanning microscopy with Airyscan, and scanning electron microscopy were then performed. HA discs and Ag HA discs were implanted subcutaneously in vivo in the dorsum of rats, and MRSA suspensions containing a mean in vivo 7.2 (SD 0.4) x 106 or 72.0 (SD 4.2) x 105 CFUs were inoculated on the discs. VCM was injected subcutaneously daily every 12 hours followed by viable cell counting. RESULTS: Biofilms that formed on HA discs were thicker and larger than those on Ti discs, whereas those on Ag-HA discs were thinner and smaller than those on Ti discs. Viable bacterial counts in vivo revealed that Ag-HA combined with VCM was the most effective treatment. CONCLUSION: Ag-HA with VCM has a potential synergistic effect in reducing MRSA biofilm formation and can thus be useful for preventing and treating PJI.Cite this article: Bone Joint Res. 2020;9(5):211-218.

Antibacterial Activity of Ag-Hydroxyapatite Coating Against Hematogenous Infection by Methicillin-Resistant Staphylococcus aureus in the Rat Femur.

Several antibacterial materials have been developed to prevent periprosthetic joint infection and thus prevent serious complications for patients and surgeons. However, no study has addressed the activity of antibacterial materials against hematogenous infection. The present study evaluated the antibacterial activity of a silver-containing hydroxyapatite-coated implant against methicillin-resistant Staphylococcus aureus (MRSA) hematogenous infection. Implants coated with hydroxyapatite and silver-hydroxyapatite were inserted into rats' right and left femurs, respectively, after which the animals were infected with S. aureus via a tail vessel. About 107 colony-forming units was the optimal bacterial number for the establishment of S. aureus hematogenous infection. Bacterial loads and C-reactive protein in the blood were measured to confirm bacteremia and inflammation. Fourteen days after the infection, bacterial loads were statistically lower in the femurs containing silver-hydroxyapatite-coated implants than in those with hydroxyapatite-coated implants (p = 0.022). Thus, silver-hydroxyapatite-coated implants might provide antibacterial activity against MRSA hematogenous infection in the postoperative period. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2655-2660, 2019.

Cold storage conditions modify microRNA expressions for platelet transfusion.

MicroRNAs (miRNAs) are small RNA molecules that modulate gene and protein expression in hematopoiesis. Platelets are known to contain a fully functional miRNA machinery. While platelets used for transfusion are normally stored at room temperature, recent evidence suggests more favorable effects under a cold-storage condition, including higher adhesion and aggregation properties. Thus, we sought to determine whether functional differences in platelets are associated with the differential profiling of platelet miRNA expressions. To obtain the miRNA expression profile, next-generation sequencing was performed on human platelets obtained from 10 healthy subjects. The miRNAs were quantified after being stored in three different conditions: 1) baseline (before storage), 2) stored at 22°C with agitation for 72 h, and 3) stored at 4°C for 72 h. Following the identification of miRNAs by sequencing, the results were validated at the level of mature miRNAs from 18 healthy subjects, by using quantitative polymerase chain reaction (qPCR). Differential expression was observed for 125 miRNAs that were stored at 4°C and 9 miRNAs stored at 22°C as compared to the baseline. The validation study by qPCR confirmed that storage at 4°C increased the expression levels (fold change 95% CI) of mir-20a-5p (1.87, p<0.0001), mir-10a-3p (1.88, p<0.0001), mir-16-2-3p (1.54, p<0.01), and mir-223-5p (1.38, p<0.05), compared with those of the samples stored at 22°C. These results show that miRNAs correlate with platelet quality under specific storage conditions. The data indicate that miRNAs could be potentially used as biomarkers of platelet quality.

Preliminary study on the effects of movement velocity training of the upper limbs on gait ability in older adults: a nonrandomized controlled trial.

Purpose: Movement velocity of the limbs or trunk plays an important determinant of gait speed in older adults. Movement velocity-focused training of the lower limbs or trunk has recently been shown to be an effective intervention to improve gait ability. Because movement velocities of various body regions are significantly correlated, movement velocity training of the upper limbs may also be effective for improving gait speed. Therefore, the purpose of this study was to investigate whether movement velocity training of the upper limbs in a seated position is effective for improving gait ability. Patients and methods: This study was a nonrandomized controlled trial. The participants were older adults residing in geriatric health service facilities. They were assigned to the movement velocity training of the upper limbs group (n=26) or control group (n=15). The participants in the training group performed exercises (three times per week for 10 weeks) to move the upper limbs as quickly as possible. The outcomes were gait speed, movement velocity, and quadriceps strength. These measurements were performed preintervention and 4, 8, and 10 weeks after intervention. Results: A significant time-group interaction was found for maximum gait speed and movement velocity of the upper limbs. Bonferroni post-hoc test showed significant improvement in gait speed between preintervention and 10 weeks after intervention in the training group. The movement velocity of the upper limbs was significantly improved between preintervention and 4, 8, and 10 weeks after intervention. Conclusion: Movement velocity training of the upper limbs showed significant and clinically relevant improvements in maximum gait speed at 10 weeks after intervention. This training is a potentially useful intervention and can be safely performed.

[Myeloid Sarcoma of the Testis].

A 68-year-old man with swelling of his left testis was referred to our hospital. There was no history of hematologic disease. The diameter of the testicular mass was 40 mm. We performed a left orchiectomy. Histopathologic examination revealed diffuse infiltration of immature neoplastic cells with a high nuclearcytoplasmic ratio. Immunohistochemical analysis revealed that cells were positive for myeloperoxidase, while T-cell and B-cell markers were negative. There was no evidence of leukemia cells in peripheral blood or in bone marrow. The tumor was diagnosed as a testicular isolated myeloid sarcoma. Eleven months after the orchiectomy, enlargement of the para-aortic lymph node occurred. There was no evidence of leukemia cells in the peripheral blood or bone marrow. The patient is undergoing chemotherapy for recurrence of myeloid sarcoma. Myeloid sarcoma is an extramedullary tumor composed of immature myeloid cells. Myeloid sarcoma primarily involving the testis is rare. However, it is important to consider it as a differential diagnosis because it has a poor prognosis.

Beneficial effects of protease preparations derived from Aspergillus on the colonic luminal environment in rats consuming a high-fat diet.

The present study investigated the effects of the dietary addition of the protease preparations derived from Aspergillus on the colonic luminal environment. Rats were fed a 30% beef tallow diet with or without the protease preparations, including Amano protease (protease A 'Amano SD', neutral proteases from Aspergillus spp.) or orientase (orientase AY, acid proteases from Aspergillus niger) at the dose of 0.2% for 3 weeks. Cecal Bifidobacterium was significantly elevated in the dietary Amano protease group (194-fold, P<0.05), but not in the orientase group. Lactobacillus was elevated in the two groups (P<0.05). Cecal n-butyrate, propionate and lactate were higher in the Amano protease and orientase groups compared with the controls (P<0.05). Fecal immunoglobulin A and mucins were elevated in the Amano protease group (P<0.05). These results suggest the potential effect of the consumption of Aspergillus-derived protease preparations that are favorable for the colonic luminal environment in rats fed a high-fat diet.

Tumor signatures of PTHLH overexpression, high serum calcium, and poor prognosis were observed exclusively in clear cell but not non clear cell renal carcinomas.

High serum calcium (Ca) due to aberrant secretion of tumor parathyroid hormone-like hormone (PTHLH) is a well-known paraneoplastic sign and is associated with poor prognosis in patients with renal cell carcinoma (RCC). However, the status of serum Ca and tumor PTHLH expression have not been verified using the 2004 World Health Organization (WHO) renal tumor classification. We retrospectively reviewed corrected serum Ca levels at initial onset (n = 683) and/or as of recurrence (n = 71) in patients with RCC. We also examined a total of 623 renal parenchymal tumor samples for PTHLH mRNA expressions by quantitative real-time PCR. High serum Ca concomitant with PTHLH overexpression in tumors was observed exclusively in clear cell RCC but not in other non clear cell subtype tumors, including papillary, chromophobe, collecting-duct, unclassified, and other rare subtype RCCs or in benign oncocytomas and angiomyolipomas. In clear cell RCC, PTHLH expression was significantly high in male patients, and was associated with a symptomatic presentation, higher grade, and higher stage cases, whereas it was not associated with VHL gene status. Univariate analyses demonstrated that high PTHLH expression was strongly associated with poor outcome both in overall survival (OS) and disease-free survival (DFS) for patients who underwent standard nephrectomy. Further multivariate Cox analyses revealed that the PTHLH expressions remained as independent prognostic parameters for OS but not for DFS. These data suggest that the previously characterized tumor signatures of high serum Ca due to high PTHLH expression and poor prognosis are clear cell RCC-specific features, whereas these characteristics are rare in non clear cell RCCs.

[Effect of prophylactic intravesical instillation of pirarubicin to prevent recurrent bladder tumors following nephroureterectomy for upper urinary tract cancer].

We retrospectively evaluated 23 patients who had been administered pirarubicin by intravesical instillation once weekly for 5 weeks, after undergoing surgery for upper urinary tract cancer between May 2003 and October 2008. We compared their clinical records with those of 19 patients with upper urinary tract cancer subjected to nephroureterectomy between 1998 and 2008, and who did not receive intravesical instillation of pirarubicin. This prophylactic therapy was well tolerated and contributed to reduce the rate of bladder recurrence. The non-recurrence rate at 2 years was 87.0% in the instillation group and 68.4% in the non-instillation group (P＝0.0025). The overall analysis of the study population did not reveal any statistically significant risk factors of bladder recurrence.

First report on invasion of yellow fever mosquito, Aedes aegypti, at Narita International Airport, Japan in August 2012.

The invasion of the yellow fever mosquito Aedes aegypti at Narita International Airport, Japan was detected for the first time. During the course of routine vector surveillance at Narita International Airport, 27 Ae. aegypti adults emerged from larvae and pupae collected from a single larvitrap placed near No. 88 spot at passenger terminal 2 on August 8, 2012. After the appearance of Ae. aegypti in the larvitrap, we defined a 400-m buffer zone and started an intensive vector survey using an additional 34 larvitraps and 15 CO2 traps. International aircraft and passenger terminal 2 were also inspected, and one Ae. aegypti male was collected from the cargo space of an international aircraft from Darwin via Manila on August 28, 2012. Larvicide treatment with 1.5% fenitrothion was conducted in 64 catch basins and one ditch in the 400-m buffer zone. Twenty-four large water tanks were also treated at least once with 0.5% pyriproxyfen, an insect growth regulator. No Ae. aegypti eggs or adults were found during the 1-month intensive vector survey after finding larvae and pupae in the larvitrap. We concluded that Ae. aegypti had failed to establish a population at Narita International Airport.

Nonfunctioning juxtaglomerular cell tumor.

The juxtaglomerular cell tumor (JGCT) is a rare renal tumor characterized by excessive renin secretion causing intractable hypertension and hypokalemia. However, asymptomatic nonfunctioning JGCT is extremely rare. Here, we report a case of nonfunctioning JGCT in a 31-year-old woman. The patient presented with a left renal tumor without hypertension or hypokalemia. Under a clinical diagnosis of renal cell carcinoma, radical nephrectomy was performed. The tumor was located in the middle portion adjacent to the renal pelvis, measuring 2 cm in size. Pathologically, the tumor was composed of cuboidal cells forming a solid arrangement, immunohistochemically positive for renin. Based on these findings, the tumor was diagnosed as JGCT. In cases with hyperreninism, preoperative diagnosis of JGCT is straightforward but difficult in nonfunctioning case. Generally, JGCT presents a benign biological behavior. Therefore, we should take nonfunctioning JGCT into the differential diagnoses for renal tumors, especially in younger patients to avoid excessive surgery.

[Assessment of clinical features in solitary minimum size (<1 cm) bladder cancer].

We retrospectively evaluated primary non-muscle-invasive bladder cancer diagnosed between 1999 and 2008 at 2 facilities (Kawasaki Municipal Hospital and Yokohama Minami Kyosai Hospital). Size (< 1 cm) solitary bladder cancer statistically evaluated the characteristics. Out of 463 bladder cancers, 52 were minimum-size solitary pTa bladder cancers less than 1 cm in diameter. The average follow-up period was 50.9 months. The recurrence rate of the minimum-size bladder cancer was significantly lower than that of bladder cancers of other sizes (1 to 3 cm or ≥ 3 cm). The 3-year non-recurrence rate was 80.7,71.0,and 62.9% in each group (< 1, 1 to 3, ≥ 3 cm). High-grade minimum size bladder cancer (pTa) showed a significantly higher recurrence rate than the low-grade cases (P = 0.0101). Intravesical chemotherapy with anti-cancer drugs significantly reduced the intravesical recurrence rate in the low-grade minimum-size bladder cancer group (P = 0.0418). There was no statistically significant difference in either the average recurrence number or the rate of multiple recurrences between the minimum-size tumor group and the 1 to 3 cm tumor group. Minimum size bladder cancer had a lower recurrence rate than tumors of other sizes; however, there were no differences in other characteristics between the groups. Therefore, sufficient treatment, in accordance with the guidelines, should be administered for minimum size tumors as well as tumors of other sizes.

C-reactive protein in patients with advanced metastatic renal cell carcinoma: usefulness in identifying patients most likely to benefit from initial nephrectomy.

OBJECTIVE: C-reactive protein (CRP) is considered a useful serum marker for patients with RCC. However, its clinical utility in advanced metastatic renal cell carcinoma (AM-RCC), particularly in deciding whether to perform nephrectomy at the onset, is not well studied. PATIENTS AND METHODS: We retrospectively evaluated 181 patients with AM-RCC, including 18 patients underwent potentially curative surgery, 111 underwent cytoreductive nephrectomy, and 52 received medical treatment only. CRP cutoff points were determined by receiver operating characteristic (ROC) curve analysis. Kaplan-Meier and Cox regression analyses were used for survival tests. RESULTS: ROC analysis suggested that grouping patients according to 3 CRP ranges was a rational model. Patients with highly elevated CRP (≥67.0 mg/L) presented remarkably poor prognosis despite treatment (nephrectomy or medical treatment only). Cox regression models demonstrated that risk factors of overall survival for patients who underwent nephrectomy were the CRP ranges defined in this study (≤18.0 mg/L, >18.0 and <67.0 mg/L, and ≥67.0 mg/L), ECOG PS (0, 1, and ≥2), and number of metastatic organ sites (0-1 and ≥2). The retrospective design is a limitation of this study. CONCLUSION: Our study demonstrated that the serum CRP level is a statistically significant prognostic parameter for patients with AM-RCC. The data also indicated that pretreatment serum CRP level provides useful prognostic information that helps in deciding whether to perform initial nephrectomy for patients with AM-RCC.

Early assessment by FDG-PET/CT of patients with advanced renal cell carcinoma treated with tyrosine kinase inhibitors is predictive of disease course.

BACKGROUND: We reported previously that (18)F-2-fluoro-2-deoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) had potential for evaluating early response to treatment by tyrosine kinase inhibitors (TKIs) in advanced renal cell carcinoma (RCC). This time we investigated the relation of the early assessment by FDG PET/CT to long-term prognosis with an expanded number of patients and period of observation. METHODS: Patients for whom TKI treatment for advanced RCC was planned were enrolled. FDG PET/CT was performed before TKI treatment and after one month of TKI treatment. The relations of the FDGPET/CT assessment to progression free survival (PFS) and overall survival (OS) were investigated. RESULTS: Thirty-five patients were enrolled (sunitinib 19 cases, sorafenib 16 cases). The patients with RCC showing high SUVmax in pretreatment FDG PET/CT demonstrated short PFS (P =0.024, hazard ratio 1.137, 95% CI 1.017-1.271) and short OS (P =0.004, hazard ratio 1.210 95% CI 1.062-1.379). Thirty patients (sunitinib 16 cases, sorafenib 14 cases) were evaluated again after 1 month. The PFS of the patients whose SUVmax decreased<20% was shorter than that of the patients whose SUVmax decreased<20% (P = 0.027, hazard ratio 3.043, 95% CI 1.134-8.167). The PFS of patients whose tumor diameter sum increased was shorter than that of the patient with tumors whose diameter sum did not (P =0.006, hazard ratio 4.555, 95% CI 1.543-13.448). The patients were classified into three response groups: good responder (diameter sum did not increase, and SUVmax decreased ≥ 20%), intermediate responder (diameter sum did not increase, and SUVmax decreased<20%), and poor responder (diameter sum increased, or one or more new lesions appeared). The median PFS of good, intermediate, and poor responders were 458 ± 146 days, 131 ± 9 days, and 88 ± 26 days (good vs. intermediate P = 0.0366, intermediate vs. poor P = 0.0097, log-rank test). Additionally the mean OSs were 999 ± 70 days, 469 ± 34 days, and 374 ± 125 days, respectively (good vs. intermediate P = 0.0385, intermediate vs. poor P = 0.0305, log-rank test). CONCLUSIONS: The evaluation of RCC response to TKI by tumor size and FDG uptake using FDG PET/CT after 1 month can predict PFS and OS.

[Assessments of progression in non-muscle-invasive bladder cancer].

We retrospectively studied 463 patients with primary non-muscle-invasive bladder cancer diagnosed between 1999 and 2008 at two facilities (Kawasaki Municipal Ida Hospital and Yokohama Minami Kyosai Hospital). In this study, disease progression was defined as invasion to the muscle or further (upstage) and presence of metastasis (metastasis). We detected progression in 22 cases, including 18 upstages and 4 metastasis. Univariate analysis showed that factors associated with progression were T category (pT1 p< 0.0001), grade (high grade p< 0.0001, G3 p< 0.0001) and number of tumors (multiple p=0.0213). Multivariate analysis showed that the only equivocal factor associated with progression was T category (T1). Use of a second tansurethral resection for high-grade pT1 cases was unrelated to progression. Among the patients with progression, many had a more advanced T category at the time of radical treatment, and the results of treatment were poor. The factors associated with progression of bladder cancer should be investigated in more detail, so that early radical treatment can be initiated in eligible patients.

[A case of primary seminal vesicle cancer detected by FDG-PET/CT].

We reported a case of primary seminal vesicle cancer, detected by FDG-PET/CT. A 65-year-old man with constipation and appetite loss was admitted to our hospital. An ultrasound examination revealed evidence of bilateral hydronephrosis. He was diagnosed as acute post renal failure, and nephrostomy was done. CT and MRI showed a solid mass in the area of seminal vesicle. He underwent transrectal core biopsy, which histologically showed poorly differentiated adenocarcinoma. Immunohistochemistry showed the tumor to be CA125 positive, CEA positive and CK7 positive but PSA negative. FDG-PET/CT revealed an increased uptake of FDG only in the area of seminal vesicle. Serum CA125 was elevated and PSA stayed within normal limit. Primaly rectal carcinoma was ruled out by colonoscopy. The result of transperineal prostate biopsy was negative. We diagnosed him as suffering from primary seminal vesicle carcinoma. Anti-androgen blockade and radiotherapy to whole pelvis were performed, and serum CA125 level was improved. But, 6 months later serum CA125 re-elevated and 19 months later multiple liver metastases were noted. The patient received two cycles of docetaxel and cisplatin chemotherapy, however he developed pulmonaly embolism and rectal bleeding by tumor invasion and he died of his disease 22 months after the diagnosis.

Retroperitoneoscopic radical nephrectomy with a small incision for renal cell carcinoma: comparison with the conventional method.

PURPOSE: When retroperitoneoscopic radical nephrectomy for renal cell carcinoma was introduced into our institution, we performed a combined small skin incision method. In this method, a small incision was made to approach the retroperitoneal space prior to setting trockers and thereafter a LAPDISC was placed in the incision to start the retroperitoneoscopic procedure. In this study, we compared the outcomes between the combined small skin incision method ("A method" hereinafter) and the conventional method ("B method" hereinafter). MATERIAL AND METHODS: Among the cases of T1N0M0 suspicious renal cell carcinoma treated at Yokohama City University between May 2003 and June 2009, the A method was performed in 51 cases and the B method was performed in 33 cases. The factors in the outcomes compared between the A and B methods were the duration of procedure, volume of bleeding, volume of transfusion, weight of the specimen, incidence of peritoneal injury, rate of conversion to open surgery, and perioperative complications. RESULTS: The duration of the procedure was 214.4 ± 46.9 minutes in the A method group and 208.1 ± 36.4 minutes in the B method group (p = 0.518). The volume of bleeding and the weight of the specimen were 105.5 ± 283.2 ml and 335.1 ± 137.4 g in the A method group and 44.8 ± 116 ml (p = 0.247) and 309.2 ± 126 g (p = 0.385) in the B method group. There was no significant difference in all factors analyzed. CONCLUSION: The A method would be highly possible to produce stable results, even during the introduction period when the staff and the institution are still unfamiliar with the retroperitoneoscopic surgery.