Comparative Characterization of Maxillary Expansion and Alternate Maxillary Expansions and Constrictions in Rats

The purpose of this study was to evaluate whether the cranial and circumaxillary sutures react differently to maxillary expansion （ME） and alternate maxillary expansions and constrictions （Alt-MEC） in a rat model. Twenty-two male Sprague-Dawley rats （6 weeks old） were used and divided into three groups. In ME group （n=9）, an expander was activated for 5 days. In Alt-MEC group （9 animals）, an al- ternate expansion and constriction protocol （5-day expansion and 5-day constriction for one cycle） was conducted for 2.5 cycles （25 days total）. The control group comprised 4 animals with no appliances used, each of two sacrificed on day 5 and day 25 respectively. Midpalatal suture expansion or constriction levels were assessed qualitatively and quantitatively by bite-wing X-rays and cast models. Distances between two central incisors and two maxillary first molars were measured on cast models after each activation. Circumaxillary sutures （midpalatal, maxillopalatine, premaxillary, zygomaticotemporal and frontonasal suture） in each group were characterized histologically. Results showed that midpalatal suture was wid- ened and restored after each expansion and constriction. At the end of activation, the widths between both central incisors and first molars in Alt-MEC group were significantly larger than those in ME group （P〈0.05）. Histologically, all five circumaxillary sutures studied were widened in multiple zones in Alt- MEC group. However, only midpalatal suture was expanded with cellular fibrous tissue filling in ME group. Significant osteoclast hyperplasia was observed in all circumaxillary sutures after alternate expan- sions and constrictions, but osteoclast count increase was only observed in midpalatal suture in ME group. These results suggested that cranial and circumaxillary sutures were actively reconstructed after Alt-MEC, while only midpalatal suture had active reaction after ME.

Healing time of incision infection after hepatobiliary surgery treated by needle-free incision suture closure

AIM:To compare the effectiveness of needle-free incision suture closure with butterfly tape and traditional secondary suturing techniques in treating incision infection.METHODS:Two hundred and twenty-three patients with incision infection following hepatobiliary surgery at a tertiary hospital were randomly divided into three groups:90 patients were closed by needle-free incision suture closure,which gradually closed the incision wound when drainage from incision infection was visibly decreased and healthy granulation tissues had grown;79 patients were closed by butterfly bandage;another 54 patients were closed by traditional secondary suturing technique.Healing time of incision infection was calculated from the beginning of dressing change to the healing of the incision.RESULTS:Healing time in the needle-free incision suture closure group(24.2±7.2 d)was significantly shorter than that in the butterfly bandage group(33.3±11.2 d)and the traditional secondary suturing group(36.2±15.3 d)(P<0.05).Healing time in the butterfly bandage group appeared to be slightly shorter than that in the secondary suture group,but the difference was not statistically significant(P>0.05).CONCLUSION:Needle-free incision suture closure could gradually close the infection wound at the same time of drainage and dressing change,thereby shortening the healing time.