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MP13-11 CLASSIFICATION AND ENDOSCOPIC REPAIR OF PROSTATIC URETHRAL OBSTRUCTION AFTER HIFU
THE JOURNAL OF UROLOGYâ
Vol. 191, No. 4S, Supplement, Saturday, May 17, 2014
MP13-09 TOWARDS OPTIMIZING THE OUTCOME OF DIRECT VISION INTERNAL URETHROTOMY: LONG-TERM RESULTS OF A LARGE CONTEMPORARY SERIES Ahmed Harraz*, Helmy Omar, Mohamed Tharwat, Hashim Farg, Ahmed El-Assmy, Ahmed Mosbah, Atallah Shaaban, Mansoura, Egypt INTRODUCTION AND OBJECTIVES: Direct vision internal urethrotomy (DVIU) is the first option for the treatment of short anterior urethral strictures. However, long-term outcome is not favorable. Our purpose is to determine patients at risk of recurrence in a large contemporary series. METHODS: We retrospectively analyzed the data sheets for adult patients (>18 years) underwent DVIU for urethral strictures between January 2002 and January 2013. Patients’ demographics and stricture characteristics by retrograde urethrography and operative findings were analyzed. The primary outcome is the development of failure defined as the need for any further intervention e.g. endoscopic or substitution after catheter removal. Univariable and multivariable analyses were used to identify patients at risk of failure. RESULTS: A total of 563 patients with a mean SD age of 49.9 15.9 years were analyzed during the specified period. The main cause of stricture was idiopathic in 51.9% and the strictures were multiple in 17 (12.4%) patients with median diameter and length of 2 mm and 6 mm, respectively. Recurrence developed in 128 (22.7%) patients over a median followup of 36 months (3-280). Patients developed recurrent strictures were obese (p ¼ 0.012). Post-traumatic and idiopathic strictures had higher incidence of recurrence than iatrogenic and inflammatory strictures (p ¼ 0.001) while distal strictures had significantly more tendency to recur than proximal strictures (p ¼ 0.01). None of the stricture characteristics by retrograde urethrography was significantly associated with recurrence. On binary logistic regression analysis, obese patients (OR: 1.7; p ¼ 0.013), distal strictures (OR: 2; p ¼ 0.011) and traumatic strictures (OR: 1.7; p ¼ 0.05) were independent predictors for stricture recurrence. Furthermore, distal strictures (b ¼ 0.1; p ¼ 0.016) and positive urine culture (b ¼ 0.1; p ¼ 0.012) were independent predictors for increased number of recurrence by linear regression. CONCLUSIONS: obese patients developed post-traumatic strictures at distal anterior urethra are at high risk for recurrence following DVIU. The presence of associated urinary tract infection increases the odds of recurrence frequency. Source of Funding: none
MP13-10 URETHRAL TISSUE ENGINEERING USING ACELLULAR BI-LAYER SILK SCAFFOLDS IN A RABBIT URETHROPLASTY MODEL Duong Tu*, YeunGoo Chung, Debra Franck, Boston, MA; Eun Seok Gil, Medford, MA; Khalid Algarrahi, Boston, MA; David Kaplan, Medford, MA; Carlos Estrada, Joshua Mauney, Boston, MA INTRODUCTION AND OBJECTIVES: The development of “off the shelf” acellular biomaterial options for urethral reconstruction is an ongoing challenge. Matrices derived from Bombyx mori silkworms represent attractive candidates for urethral tissue engineering given their mechanical robustness, processing plasticity, low immunogenicity, and biodegradability. Our previous results have shown that bi-layer silk (BLS) scaffolds support tissue regeneration and functionality in both rodent and porcine models of bladder augmentation. We hypothesized that acellular BLS matrices would mediate tissue regeneration in a rabbit model of urethral repair. METHODS: Fourteen male rabbits were divided into 4 experimental groups. Onlay urethroplasties were performed in two groups with either BLS (Group 1, N¼4) or small intestinal submucosa (Group 2, N¼4) scaffolds of equal size (1x2cm2). Control groups were subjected to either skin incision and closure (Group 3, N¼3) or ventral urethral excision and closure (Group 4, N¼3) to ascertain the effect of surgical
e179
procedures alone. Serial retrograde urethrography (RUG) was performed preoperatively, and at 1 and 3 months post-op to assess for stricture. Following 3 months of implantation, regenerated tissues were evaluated by histological (H&E and Masson’s trichrome) and immunohistochemical (IHC) analyses for smooth muscle contractile proteins (a-actin and SM22a), epithelial (cytokeratins), innervation (synaptophysin) and vascularization (CD31) markers. RESULTS: No evidence of stricture formation was demonstrated on RUG at all time points, and normal urethral caliber was observed in all groups. Histological and IHC evaluations of the regenerated tissues supported by both SIS and BLS scaffolds demonstrated robust smooth muscle formation as well as a multilayered epithelium, similar to control groups. Innervation and vascularization markers were also apparent in the regenerated tissue of each group. In contrast to BLS scaffold implantation, SIS matrices elicited chronic inflammatory reactions that were noted by follicular aggregates of mononuclear cells present throughout the regenerated submucosa. CONCLUSIONS: Acellular bi-layer silk scaffolds represent an effective biomaterial for urethral onlay repair in a rabbit model capable of supporting tissue regeneration and functionality. BLS scaffolds demonstrate superior urethral biocompatibility in comparison to conventional materials such as SIS and may represent a promising new option for urethral reconstruction. Source of Funding: NIH/NIDDK R00 DK083616-01A2 (MAUNEY); Tissue Engineering Resource Center, NIH/ NIBIB P41 EB002520 (KAPLAN); NIH/NIDDK T32-DK60442 (FREEMAN)
MP13-11 CLASSIFICATION AND ENDOSCOPIC REPAIR OF PROSTATIC URETHRAL OBSTRUCTION AFTER HIFU Stefan Thueroff*, Munich, Germany; Christian Chaussy, Regensburg, Germany INTRODUCTION AND OBJECTIVES: Post-HIFU obstruction caused by fibrotic stenosis in different locations within the prostatic capsule is the most common side effect after “radical HIFU” (TUR & complete HIFU), obstruction caused by necrotic tissue is rare and in mostly combined with bladder neck stenosis. We classified post-HIFU infravesical obstructions, analyse their frequency and describe endoscopical repair of different types. METHODS: We extracted the relevant group from prospective Harlaching HIFU database (n¼2.735), reviewed the HIFU-files and OR-Reports and categorized different types of obstructions. RESULTS: 19.5% (n¼533) of 2.735 HIFU treatments performed in our department since `96 needed secondary endourological intervention for postoperative infravesical obstruction. 4 “types” of TUR/ HIFU shrinkage induced infravesical stenosis were identified: "classical bladderneck stenosis" in combination with necrotic residual tissue in 12% (typ I), intraprostatic "sand glass" stenosis in 5% (typ II), apicoretrosphincteric stenosis in 2% (typ III) and classical penile urethral stenosis in < 0.5% (typ IV). Reason for typ I was insufficient neoadjuvant TUR, type II correlated to small preoperative prostatic volume, type III to insufficient apical TUR with residual tissue transformed to fibrosis, typ IV as typical side effect of TUR -not HIFU related-. "Endo-V-Plastic" was developed to open fast, safe and effective intraprostatic type I-III stenosis without a trauma of previous dilatations. CONCLUSIONS: Post-HIFU obstruction after TURP & HIFU is common and mostly correlated to small prostates and good oncological outcome. HIFU induced shrinkage of the prostatic capsule induces intracapsular “sand glass” type stenosis in 3 different locations and occurs typically 6-9 months after 1/2 a year of asymptomatic micturition. In contrast obstruction caused by necrotic tissue occurs early and does not have the interval of asymptomatic micutrition. “Endo-V-plastic” showed to be a simple and fast repair for stenosis repair, cold-loop curettage the adequat therapy for necrotic tissue resection.
THE JOURNAL OF UROLOGYâ
e180
Vol. 191, No. 4S, Supplement, Saturday, May 17, 2014
Source of Funding: none
MP13-13 Source of Funding: Harlachinger Krebshilfe e.V. powered by Lingen foundation
MP13-12 MIDTERM FOLLOW UP OF INTERNAL URETHROTOMY IN PATIENTS WITH RECURRENT URETHRAL STRICTURE AFTER BUCCAL MUCOSA GRAFT URETHROPLASTY Clemens Rosenbaum*, Marianne Schmid, Tim Alexander Ludwig, Philip Reiss, Roland Dahlem, Oliver Engel, Silke Riechardt, Margit Fisch, Sascha Ahmadreza Ahayi, Hamburg, Germany INTRODUCTION AND OBJECTIVES: To determine the success rate of internal urethrotomy (IU) in the treatment of short stricture recurrences after buccal mucosa urethroplasty (BMGU). METHODS: All patients who underwent IU for the treatment of short urethral stricture recurrence (< 1cm) after BMGU were identified from our prospective urethroplasty data base.These patients were evaluated by maximum flow rate (Qmax) and residual urine (RU) measurements. Stricture recurrence was determined when maximum flow rate (Qmax) was < 10 ml/s and a stricture verified in a combined retro- and antegrade voiding cystography (VC) or cystoscopy. Endpoints of our retrospective study was to determine the success rate of IU and possible risk factors of stricture recurrence after IU. RESULTS: A total of 27 IU patients after failed BMGU were identified. Mean FU of this study cohort was 12.4 months (range 1-32). At baseline mean age was 60 years (range 19-79). A bulbar BMGU was performed in 89% and a penile urethroplasty in 11% respectively. Mean length of the graft used was 6 cm. Relapse occurred proximal to the graft in 71%, distal to the graft in 29% After IU stricture recurrence was observed in 44.4% of our study patients. Mean Qmax in FU was 16.59 ml/s, mean RU was 91 ml. According to Kaplan Meyer Analysis at 30 months the success rate of IU was about 50% (see figure 1). Neither age nor a history of radiotherapy nor number of previous urethral surgeries were statistically significantly associated with stricture recurrence after IU. In linear regression length of the graft showed borderline statistical significance (p¼0.078). CONCLUSIONS: At midterm FU IU after BMGU showed a fair success rate and might be a viable option in paients with very short strictures after BMGU. Longer FU is warranted.
PROPENSITY MATCHED COMPARISON OF MORBIDITY AND COSTS OF OPEN VS. MINIMALLY INVASIVE RADICAL NEPHROURETERECTOMY: A CONTEMPORARY POPULATIONBASED ANALYSIS IN THE UNITED STATES Jeffrey Leow*, Joaquim Bellmunt, Toni Choueiri, Boston, MA; Benjamin Chung, Stanford, CA; Steven Chang, Boston, MA INTRODUCTION AND OBJECTIVES: Nephroureterectomy (NU) is the standard treatment for upper tract urothelial carcinoma. Minimally invasive (laparoscopic or robot-assisted) approaches have gained popularity in recent years. On a population-level, there exists limited data on its utilization, morbidity and costs in the United States. METHODS: Using the Premier Comparative Database (Premier, Inc., Charlotte, NC), which collects data from over 600 nonfederal hospitals throughout the US, we captured all patients who underwent a NU (ICD-9 code 55.51) with diagnoses of renal pelvis (189.1) or ureteral (189.2) neoplasms, from 2003 to 2010. To reduce selection bias between open and minimally invasive (MI) groups, we employed propensity-weighted statistical analyses, adjusting for clustering by hospitals and survey weighting to ensure nationally representative estimates. We evaluated 90-day mortality, postoperative complications (using Clavien classification), length of stay, and direct hospital costs. RESULTS: The weighted cohort included 26009 open and 18667 MI NUs. The 90-day mortality (Clavien 5), major (Clavien 3-5) and minor complication (Clavien 1-2) rates were 1.8%, 8.0% and 22.5% respectively. Use of MI surgery increased from 27.0% in 2003 to 49.5% in 2010 (p for trend <0.001) (Figure 1). In a propensity-weighted analysis, 90-day mortality rates (2.0% vs. 1.6%, p¼0.36; odds ratio [OR]: 0.80, 95% CI: 0.46-1.40, p¼0.44) and major complication (8.2% vs. 7.7%, p¼0.45; OR: 0.93, 95% CI: 0.70-1.24, p¼0.62) rates were similar between open and MI NU. However, MI NU had a 34% decreased odds of prolonged hospital length of stay (>median) (OR: 0.66, 95% CI: 0.55 to 0.79, p<0.001). MI NU had $1186 higher adjusted 90-day median direct hospitals (p<0.001). CONCLUSIONS: Between 2003 and 2010, the use of MI NU has increased significantly now accounting for approximately half of all procedures. There was no postoperative mortality and morbidity advantage of MI over open NU. Although hospital length of stay was shorter, MI NU still had higher direct hospital costs. Long-term oncological and functional outcomes of MI NU remain to be seen.
Vol. 191, No. 4S, Supplement, Saturday, May 17, 2014
MP13-09 TOWARDS OPTIMIZING THE OUTCOME OF DIRECT VISION INTERNAL URETHROTOMY: LONG-TERM RESULTS OF A LARGE CONTEMPORARY SERIES Ahmed Harraz*, Helmy Omar, Mohamed Tharwat, Hashim Farg, Ahmed El-Assmy, Ahmed Mosbah, Atallah Shaaban, Mansoura, Egypt INTRODUCTION AND OBJECTIVES: Direct vision internal urethrotomy (DVIU) is the first option for the treatment of short anterior urethral strictures. However, long-term outcome is not favorable. Our purpose is to determine patients at risk of recurrence in a large contemporary series. METHODS: We retrospectively analyzed the data sheets for adult patients (>18 years) underwent DVIU for urethral strictures between January 2002 and January 2013. Patients’ demographics and stricture characteristics by retrograde urethrography and operative findings were analyzed. The primary outcome is the development of failure defined as the need for any further intervention e.g. endoscopic or substitution after catheter removal. Univariable and multivariable analyses were used to identify patients at risk of failure. RESULTS: A total of 563 patients with a mean SD age of 49.9 15.9 years were analyzed during the specified period. The main cause of stricture was idiopathic in 51.9% and the strictures were multiple in 17 (12.4%) patients with median diameter and length of 2 mm and 6 mm, respectively. Recurrence developed in 128 (22.7%) patients over a median followup of 36 months (3-280). Patients developed recurrent strictures were obese (p ¼ 0.012). Post-traumatic and idiopathic strictures had higher incidence of recurrence than iatrogenic and inflammatory strictures (p ¼ 0.001) while distal strictures had significantly more tendency to recur than proximal strictures (p ¼ 0.01). None of the stricture characteristics by retrograde urethrography was significantly associated with recurrence. On binary logistic regression analysis, obese patients (OR: 1.7; p ¼ 0.013), distal strictures (OR: 2; p ¼ 0.011) and traumatic strictures (OR: 1.7; p ¼ 0.05) were independent predictors for stricture recurrence. Furthermore, distal strictures (b ¼ 0.1; p ¼ 0.016) and positive urine culture (b ¼ 0.1; p ¼ 0.012) were independent predictors for increased number of recurrence by linear regression. CONCLUSIONS: obese patients developed post-traumatic strictures at distal anterior urethra are at high risk for recurrence following DVIU. The presence of associated urinary tract infection increases the odds of recurrence frequency. Source of Funding: none
MP13-10 URETHRAL TISSUE ENGINEERING USING ACELLULAR BI-LAYER SILK SCAFFOLDS IN A RABBIT URETHROPLASTY MODEL Duong Tu*, YeunGoo Chung, Debra Franck, Boston, MA; Eun Seok Gil, Medford, MA; Khalid Algarrahi, Boston, MA; David Kaplan, Medford, MA; Carlos Estrada, Joshua Mauney, Boston, MA INTRODUCTION AND OBJECTIVES: The development of “off the shelf” acellular biomaterial options for urethral reconstruction is an ongoing challenge. Matrices derived from Bombyx mori silkworms represent attractive candidates for urethral tissue engineering given their mechanical robustness, processing plasticity, low immunogenicity, and biodegradability. Our previous results have shown that bi-layer silk (BLS) scaffolds support tissue regeneration and functionality in both rodent and porcine models of bladder augmentation. We hypothesized that acellular BLS matrices would mediate tissue regeneration in a rabbit model of urethral repair. METHODS: Fourteen male rabbits were divided into 4 experimental groups. Onlay urethroplasties were performed in two groups with either BLS (Group 1, N¼4) or small intestinal submucosa (Group 2, N¼4) scaffolds of equal size (1x2cm2). Control groups were subjected to either skin incision and closure (Group 3, N¼3) or ventral urethral excision and closure (Group 4, N¼3) to ascertain the effect of surgical
e179
procedures alone. Serial retrograde urethrography (RUG) was performed preoperatively, and at 1 and 3 months post-op to assess for stricture. Following 3 months of implantation, regenerated tissues were evaluated by histological (H&E and Masson’s trichrome) and immunohistochemical (IHC) analyses for smooth muscle contractile proteins (a-actin and SM22a), epithelial (cytokeratins), innervation (synaptophysin) and vascularization (CD31) markers. RESULTS: No evidence of stricture formation was demonstrated on RUG at all time points, and normal urethral caliber was observed in all groups. Histological and IHC evaluations of the regenerated tissues supported by both SIS and BLS scaffolds demonstrated robust smooth muscle formation as well as a multilayered epithelium, similar to control groups. Innervation and vascularization markers were also apparent in the regenerated tissue of each group. In contrast to BLS scaffold implantation, SIS matrices elicited chronic inflammatory reactions that were noted by follicular aggregates of mononuclear cells present throughout the regenerated submucosa. CONCLUSIONS: Acellular bi-layer silk scaffolds represent an effective biomaterial for urethral onlay repair in a rabbit model capable of supporting tissue regeneration and functionality. BLS scaffolds demonstrate superior urethral biocompatibility in comparison to conventional materials such as SIS and may represent a promising new option for urethral reconstruction. Source of Funding: NIH/NIDDK R00 DK083616-01A2 (MAUNEY); Tissue Engineering Resource Center, NIH/ NIBIB P41 EB002520 (KAPLAN); NIH/NIDDK T32-DK60442 (FREEMAN)
MP13-11 CLASSIFICATION AND ENDOSCOPIC REPAIR OF PROSTATIC URETHRAL OBSTRUCTION AFTER HIFU Stefan Thueroff*, Munich, Germany; Christian Chaussy, Regensburg, Germany INTRODUCTION AND OBJECTIVES: Post-HIFU obstruction caused by fibrotic stenosis in different locations within the prostatic capsule is the most common side effect after “radical HIFU” (TUR & complete HIFU), obstruction caused by necrotic tissue is rare and in mostly combined with bladder neck stenosis. We classified post-HIFU infravesical obstructions, analyse their frequency and describe endoscopical repair of different types. METHODS: We extracted the relevant group from prospective Harlaching HIFU database (n¼2.735), reviewed the HIFU-files and OR-Reports and categorized different types of obstructions. RESULTS: 19.5% (n¼533) of 2.735 HIFU treatments performed in our department since `96 needed secondary endourological intervention for postoperative infravesical obstruction. 4 “types” of TUR/ HIFU shrinkage induced infravesical stenosis were identified: "classical bladderneck stenosis" in combination with necrotic residual tissue in 12% (typ I), intraprostatic "sand glass" stenosis in 5% (typ II), apicoretrosphincteric stenosis in 2% (typ III) and classical penile urethral stenosis in < 0.5% (typ IV). Reason for typ I was insufficient neoadjuvant TUR, type II correlated to small preoperative prostatic volume, type III to insufficient apical TUR with residual tissue transformed to fibrosis, typ IV as typical side effect of TUR -not HIFU related-. "Endo-V-Plastic" was developed to open fast, safe and effective intraprostatic type I-III stenosis without a trauma of previous dilatations. CONCLUSIONS: Post-HIFU obstruction after TURP & HIFU is common and mostly correlated to small prostates and good oncological outcome. HIFU induced shrinkage of the prostatic capsule induces intracapsular “sand glass” type stenosis in 3 different locations and occurs typically 6-9 months after 1/2 a year of asymptomatic micturition. In contrast obstruction caused by necrotic tissue occurs early and does not have the interval of asymptomatic micutrition. “Endo-V-plastic” showed to be a simple and fast repair for stenosis repair, cold-loop curettage the adequat therapy for necrotic tissue resection.
THE JOURNAL OF UROLOGYâ
e180
Vol. 191, No. 4S, Supplement, Saturday, May 17, 2014
Source of Funding: none
MP13-13 Source of Funding: Harlachinger Krebshilfe e.V. powered by Lingen foundation
MP13-12 MIDTERM FOLLOW UP OF INTERNAL URETHROTOMY IN PATIENTS WITH RECURRENT URETHRAL STRICTURE AFTER BUCCAL MUCOSA GRAFT URETHROPLASTY Clemens Rosenbaum*, Marianne Schmid, Tim Alexander Ludwig, Philip Reiss, Roland Dahlem, Oliver Engel, Silke Riechardt, Margit Fisch, Sascha Ahmadreza Ahayi, Hamburg, Germany INTRODUCTION AND OBJECTIVES: To determine the success rate of internal urethrotomy (IU) in the treatment of short stricture recurrences after buccal mucosa urethroplasty (BMGU). METHODS: All patients who underwent IU for the treatment of short urethral stricture recurrence (< 1cm) after BMGU were identified from our prospective urethroplasty data base.These patients were evaluated by maximum flow rate (Qmax) and residual urine (RU) measurements. Stricture recurrence was determined when maximum flow rate (Qmax) was < 10 ml/s and a stricture verified in a combined retro- and antegrade voiding cystography (VC) or cystoscopy. Endpoints of our retrospective study was to determine the success rate of IU and possible risk factors of stricture recurrence after IU. RESULTS: A total of 27 IU patients after failed BMGU were identified. Mean FU of this study cohort was 12.4 months (range 1-32). At baseline mean age was 60 years (range 19-79). A bulbar BMGU was performed in 89% and a penile urethroplasty in 11% respectively. Mean length of the graft used was 6 cm. Relapse occurred proximal to the graft in 71%, distal to the graft in 29% After IU stricture recurrence was observed in 44.4% of our study patients. Mean Qmax in FU was 16.59 ml/s, mean RU was 91 ml. According to Kaplan Meyer Analysis at 30 months the success rate of IU was about 50% (see figure 1). Neither age nor a history of radiotherapy nor number of previous urethral surgeries were statistically significantly associated with stricture recurrence after IU. In linear regression length of the graft showed borderline statistical significance (p¼0.078). CONCLUSIONS: At midterm FU IU after BMGU showed a fair success rate and might be a viable option in paients with very short strictures after BMGU. Longer FU is warranted.
PROPENSITY MATCHED COMPARISON OF MORBIDITY AND COSTS OF OPEN VS. MINIMALLY INVASIVE RADICAL NEPHROURETERECTOMY: A CONTEMPORARY POPULATIONBASED ANALYSIS IN THE UNITED STATES Jeffrey Leow*, Joaquim Bellmunt, Toni Choueiri, Boston, MA; Benjamin Chung, Stanford, CA; Steven Chang, Boston, MA INTRODUCTION AND OBJECTIVES: Nephroureterectomy (NU) is the standard treatment for upper tract urothelial carcinoma. Minimally invasive (laparoscopic or robot-assisted) approaches have gained popularity in recent years. On a population-level, there exists limited data on its utilization, morbidity and costs in the United States. METHODS: Using the Premier Comparative Database (Premier, Inc., Charlotte, NC), which collects data from over 600 nonfederal hospitals throughout the US, we captured all patients who underwent a NU (ICD-9 code 55.51) with diagnoses of renal pelvis (189.1) or ureteral (189.2) neoplasms, from 2003 to 2010. To reduce selection bias between open and minimally invasive (MI) groups, we employed propensity-weighted statistical analyses, adjusting for clustering by hospitals and survey weighting to ensure nationally representative estimates. We evaluated 90-day mortality, postoperative complications (using Clavien classification), length of stay, and direct hospital costs. RESULTS: The weighted cohort included 26009 open and 18667 MI NUs. The 90-day mortality (Clavien 5), major (Clavien 3-5) and minor complication (Clavien 1-2) rates were 1.8%, 8.0% and 22.5% respectively. Use of MI surgery increased from 27.0% in 2003 to 49.5% in 2010 (p for trend <0.001) (Figure 1). In a propensity-weighted analysis, 90-day mortality rates (2.0% vs. 1.6%, p¼0.36; odds ratio [OR]: 0.80, 95% CI: 0.46-1.40, p¼0.44) and major complication (8.2% vs. 7.7%, p¼0.45; OR: 0.93, 95% CI: 0.70-1.24, p¼0.62) rates were similar between open and MI NU. However, MI NU had a 34% decreased odds of prolonged hospital length of stay (>median) (OR: 0.66, 95% CI: 0.55 to 0.79, p<0.001). MI NU had $1186 higher adjusted 90-day median direct hospitals (p<0.001). CONCLUSIONS: Between 2003 and 2010, the use of MI NU has increased significantly now accounting for approximately half of all procedures. There was no postoperative mortality and morbidity advantage of MI over open NU. Although hospital length of stay was shorter, MI NU still had higher direct hospital costs. Long-term oncological and functional outcomes of MI NU remain to be seen.