The Effect of High Temperature Intraoperative Molding on Bioabsorbable PLLA-PGA Craniofacial Fixation

Shaping a Flap Using a Bioabsorbable Mold-A Preliminary Report

Background:

We previously reported that good surgical outcomes can be obtained with breast mold made by 3-dimensional printing. However, detailed breast shape is often difficult to create. Accordingly, we aimed to determine whether transplanting a flap and bioabsorbable mold in vivo would yield better results by retaining the flap shape inside the mold during the scar formation period.

Methods:

Vascularized adipose flaps were elevated in the bilateral inguinal region of male Sprague-Dawley rats (n = 7). A cone-shaped, bioabsorbable mold (LactoSorb mesh) was created using a template. On the experimental side, the flap was inserted into the mold and fixed. On the control side, a conical flap was created using absorbable sutures, based on a template.

Results:

The flaps were harvested 3 months postoperatively, and flap volume, base area, and projection were measured with 3-dimensional imaging. Volume and base area on the mold side tended to be smaller than those on the control side (P = 0.18 and 0.13, respectively) and close to the values of the template. In addition, the ratio of projection and base area value was significantly greater on the mold side than on the control side (P = 0.04). Histology revealed little inflammatory cell invasion, and scar tissue thickness around the flap showed no significant difference between the 2 groups (P = 0.76).

Conclusions:

This study demonstrated that soft-tissue morphology can be controlled to some extent with a bioabsorbable mold. Its clinical application in breast reconstruction requires further investigation.

In vitro characteristics of a bioabsorbable suspension screw and suture system for endoscopic brow lift surgery

The time requirement for endoscopic subperiosteal brow lift fixation is as little as 10-14 days. Many types of bioabsorbable fixation have been applied to this procedure, including bioabsorbable suture coupled with a bioabsorbable bone anchor, with excellent outcomes. Typically, the anchor and suture materials differ, each having their own hydrolytic strength loss profile. The dynamic relationship between the instantaneous state of degradation of the bone anchor and the suture components can affect fixation strength and failure mode, a poorly understood phenomenon. We examined the use of 2x5 mm PLLA-PGA (82:18) copolymer screws containing a suture eyelet in the head, paired with one of four types of bioabsorbable suture (2-0 and 3-0 Vicryl and 2-0 and 3-0 PDS-II), in a model system designed to mimic brow lift fixation. Constructs were inserted into a synthetic bone substrate and incubated in pH 7.4 buffer at 37 degrees C for up to 3 weeks, then loaded to failure. Initial failure loads were dependent upon suture size but not suture material, with 2-0 suture constructs (63-70N) failing at twice the load of the 3-0 suture constructs (30-35N). The following 3 week strength retentions were obtained: 40-55% for 2-0 and 3-0 Vicryl suture, 100% for 3-0 PDS-II suture, and 58% for 2-0 PDS-II suture constructs. The predominant failure mode was suture breakage at the knot, with the later intervals utilizing 2-0 PDS-II suture including some screw head failures. This suspension screw, when coupled with an appropriate suture, appears to have suitable mechanical properties for endoscopic brow lift fixation.