ABSTRACT
Objective@#To study the learning curve of laparoscopic pacreaticoduodenectomy (LPD) with a view to find an appropriate way to develop LPD step by step.@*Methods@#112 consecutive patients who completely underwent LPD in a single surgery center at the First People’s Hospital of Changzhou from December 2015 to February 2018 were retrospectively reviewed. By using both the cumulative sum (CUSUM) and the risk-adjusted CUSUM (RA-CUSUM) methods to analyze the perioperative data of these patients, the learning curve of LPD was studied in a more scientific way.@*Results@#The learning curve could be divided into three phases: Phase 1, the initial period (the initial 45 patients); Phase 2, the enhancement period (the subsequent 31 patients); Phase 3, the maturation period (the remaining patients). For these 3 phases, the corresponding operative times were (448.4±75.0), (381.3±74.3), and (336.2±52.1) min, respectively (P<0.05). The intraoperative blood losses were (373.3±250.1), (332.3±211.6), and (265.3±253.2) ml, respectively (P<0.05). The times to oral intake were 6.0(5.0, 8.0), 5.0(3.0, 6.0), and 3.0(3.0, 5.0) days, respectively (P<0.05). The number of lymph nodes harvested were (10.0±7.0), (8.8±4.3), and (13.3±6.2), respectively (P<0.05). All these showed significant improvement through the 3 phases. On the other hand, the postoperative stays, the postoperative pancreatic fistula rates were also decreased. But these failed to reach statistical significance. Vascular reconstruction was carried out in the 48th patient in phase 2 of the study.@*Conclusions@#The initial phase of LPD passed after LPD for 46 patients, but the maturation phase occurred after LPD on 76 patients. Vascular reconstruction should be considered as passing through the learning phase rather than reaching the maturity phase. Adjustments made in the enhancement phase helped to get through the maturation phase earlier.
ABSTRACT
Objective To study the learning curve of laparoscopic pacreaticoduodenectomy ( LPD) with a view to find an appropriate way to develop LPD step by step. Methods 112 consecutive patients who completely underwent LPD in a single surgery center at the First People ' s Hospital of Changzhou from December 2015 to February 2018 were retrospectively reviewed. By using both the cumulative sum ( CUSUM) and the risk-adjusted CUSUM ( RA-CUSUM) methods to analyze the perioperative data of these patients, the learning curve of LPD was studied in a more scientific way. Results The learning curve could be divided into three phases:Phase 1, the initial period (the initial 45 patients);Phase 2, the enhancement period (the subsequent 31 patients);Phase 3, the maturation period (the remaining patients). For these 3 phases, the corresponding operative times were (448. 4 ± 75. 0), (381. 3 ± 74. 3), and (336. 2 ± 52. 1) min, respectively (P<0. 05). The intraoperative blood losses were (373. 3 ± 250. 1), (332. 3 ± 211. 6), and (265. 3 ± 253. 2) ml, respectively (P<0. 05). The times to oral intake were 6. 0(5. 0,8. 0), 5. 0 (3. 0,6. 0), and 3. 0(3. 0,5. 0) days, respectively (P<0. 05). The number of lymph nodes harvested were (10. 0 ± 7. 0), (8. 8 ± 4. 3), and (13. 3 ± 6. 2), respectively (P<0. 05). All these showed signifi-cant improvement through the 3 phases. On the other hand, the postoperative stays, the postoperative pan-creatic fistula rates were also decreased. But these failed to reach statistical significance. Vascular reconstruction was carried out in the 48th patient in phase 2 of the study. Conclusions The initial phase of LPD passed after LPD for 46 patients, but the maturation phase occurred after LPD on 76 patients. Vascular reconstruction should be considered as passing through the learning phase rather than reaching the maturity phase. Adjustments made in the enhancement phase helped to get through the maturation phase earlier.
ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the effect of core ceramic surface treatment on the failure behaviors of two bilayered all- ceramic structures.</p><p><b>METHODS</b>Lithium disilicate glass-ceramic (LDG, IPS e.max Press) and Zirconia(Cercon) specimens were divided into 4 groups(n=12) according to the following surface treatment methods: ground successively to 1 000(group A), 600(group B) and 320(group C) grit silicon carbide(SiC) papers and sandblasted with 110 µm aluminum oxide particle(group D, as control). Surface roughness was measured using a profilometer. After veneer sintering, the flexural strength σ was measured with biaxial flexure test and the reliability of strength was analyzed with Weibull distribution. Failure modes and fractographic patterns were analyzed by optical stereo and scanning electron microscopy (SEM).</p><p><b>RESULTS</b>For LDG, no significant difference was found for the flexural strength values among groups (F=0.406, P=0.750). No significant difference was found in Weibull modulus among groups(the confidence bounds overlapped with each other). SEM and optical stereo observation results showed that all the bilayered LDG specimens failed cohesively. For zirconia, Mean flexural strength values were (541 ± 75), (533 ± 73), (529 ± 78) and (640 ± 95) MPa for groups A, B, C and D, respectively, and group D demonstrated a significantly higher flexural strength compared to the other three groups(P<0.05). No significant difference were found among groups(the confidence bounds overlapped with each other). Specimens in all groups failed mainly adhesively, while those in group D presented lower percentage of adhesive failure.</p><p><b>CONCLUSIONS</b>Core ceramic surface treatment has no influence on the failure behaviors of LDG based bilayered structures. Sandblasting can increase the flexural strength of bilayered zirconia structures by reducing the incidence of delamination.</p>