BACKGROUND:Porous gradient hydroxyapatite/zirconia composite, which can adhere to a variety of cel s, such as osteoblasts, bone marrow mesenchymal stem cel s and chondrocytes, can induce and promote fracture healing or replace bone defects. OBJECTIVE:To review the development and application of porous gradient hydroxyapatite/zirconia composite in bone tissue engineering. METHODS:Articles related to porous gradient hydroxyapatite/zirconia composite in bone tissue engineering were retrieved in CNKI and PubMed databases (1971-01/2014-12). The key words were“porous bioceramic, bone tissue engineering, bone morphogenetic protein-2, induced pluripotent stem cel s”in Chinese and English, respectively. A total of 54 articles based on inclusion criteria and exclusion criteria were obtained for the review. RESULTS AND CONCLUSION:Porous gradient hydroxyapatite/zirconia composite can provide a scaffold to induce natural y forming bone growing to fil the three-dimensional pores, thus realizing the perfect integration of tissue-engineered bone material and host-bone tissue. As zirconia functions as an enhancer of hydroxyapatite, high-quality artificial bone materials, which have elastic modulus, fracture toughness and structure similar to human bone, can be prepared by adjusting the proportion and porosity of materials. Additional y, the new hydroxyapatite/zirconia foamed ceramics as tissue-engineered bone carrying bone morphogenetic protein-2/chitosan gel sustained release system and bone marrow mesenchymal stem cel s derived from induced pluripotent stem cel s wil be expected to increase bone formation and bone fusion rates significantly in the future.

Objective To explore the effect of Endoanal advancement flap(ERAF)and transanal opening of interphincteric space(TROPIS)in the treatment of complex anal fistula and their impact on anorectal pressure,so as to provide a reference for clinical selection of surgical methods.Methods Eighty-four patients with complex anal fistula admitted from October 2018 to October 2022 were divided into group E received ERAF treatment(n=48)and group T received TROPIS treatment(n=36).The clinical efficacy,operation,wound surface and anorectal pressure of the two groups were compared.Results The effective rate of treatment in Group T was 97.22％,which was higher than that in Group E(87.50％),with no statistically significant difference(P＞0.05).The surgical time[(31.53 ±7.29)minutes],intraoperative bleeding volume[(29.56±7.37)ml],and wound area[(10.03± 0.96)cm2,(8.76±0.87)cm2,(6.20±0.77)cm2]on the day of surgery,7 and 14 days after surgery in Group T were all smaller than those in Group E[(35.36±8.54)min,(36.86±8.04)ml,(12.09± 1.23)cm2,(10.52±1.09)cm2 and(7.36±0.85)cm2](P＜0.05).After surgery,the VAS score and Wexner incontinence score of Group T were(1.38±0.27)and(0.21±0.08),respectively.Group E was(1.56±0.29)and(0.33±0.09),respectively.In group T,the anorectal systolic pressure at 20 mm and 30 mm and the anorectal resting pressure at 20 mm and 30 mm were(138.18±29.58)mmHg,(136.22±35.41)mmHg,(35.47±6.58)mmHg,and(32.97±8.01)mmHg,respectively.In Group E,the data was(152.78±31.53)mmHg,(156.29±32.74)mmHg,(38.29±7.62)mmHg and(36.41±7.63)mmHg,respectively.Both groups showed a decrease in score and anorectal pressure,and group T was lower than group E(P＜0.05).The incidence of adverse reactions in Group E was 20.83％,which was higher than that in Group T(11.11％),but the difference was not statistically significant(P＞0.05).Conclusion TROPIS has a better effect in the treatment of complex anal fistula,which can shorten the operation time,reduce intraoperative bleeding,reduce postoperative pain,and protect anal function.