Irradiation at 11 kGy conserves the biomechanical properties of fascia lata better than irradiation at 25 kGy.

The objective of this study was to determine the biomechanical properties of the fascia lata and the effects of three preservation methods: freezing, cryopreservation with dimethylsulfoxide solution and lyophilization; and to compare the effects of low-dose (11 kGy) and normal-dose (25 kGy) gamma-ray sterilization versus no irradiation. 248 samples from 14 fasciae latae were collected. Freezing samples were frozen at -80 °C. Cryopreservation with dimethylsulfoxide solution samples were frozen with 10 cl dimethylsulfoxide solution at -80 °C. Lyophilization samples were frozen at -22 °C and lyophilized. Each preservation group were then randomly divided into 3 irradiation groups. The cryopreservation with dimethylsulfoxide solution samples had significantly worse results in all 3 irradiation conditions. Young's modulus was lower for the freezing samples (p < 0.001) and lyophilization samples groups (p < 0.001). Tear deformation was lower for the freezing samples (p = 0.001) and lyophilization samples groups (p = 0.003), as was stress at break (p < 0.001 and p < 0.001). Taking all preservation methods together, samples irradiated at 25 kGy had worse results than the 0 kGy and 11 kGy groups in terms of Young's modulus (p = 0.007 and p = 0.13) and of stress at break (p = 0.006 and p = 0.06). The biomechanical properties of fascia lata allografts were significantly worse under dimethylsulfoxide cryopreservation. The deleterious effects of irradiation were dose-dependent.

Effect of gamma sterilisation and deep-freezing on length and strength of fascia latae.

PURPOSE: To compare the length and strength of fascia latae after gamma sterilisation and different durations of deep-freezing. METHODS: 50 pieces of fresh porcine fascia latae were randomly divided into 5 groups. Group 1 acted as controls, which were not gamma irradiated and deep-frozen. In groups 2 to 4, fascia latae were incubated in phosphate buffer solution for 4 hours, and then gamma irradiated at 25 kGy. They were preserved at -70 degrees Celcius for one to 3 months, respectively. In group 5, fascia latae were preserved for 3 months, and during the whole process they were fixed on a wooden board to maintain their original length. The maximum tensile strength of each fascia lata was tested at a displacement rate of 1 cm per minute until failure. RESULTS: The maximum tensile strength was not significantly different among groups 1 to 4, but was significantly higher in group 5. CONCLUSION: Gamma sterilisation and deep-freezing had no effect on the strength of fascia latae, but fixation on a board could increase strength.

Effect of low dose and moderate dose gamma irradiation on the mechanical properties of bone and soft tissue allografts.

The increased use of allograft tissue for musculoskeletal repair has brought more focus to the safety of allogenic tissue and the efficacy of various sterilization techniques. Gamma irradiation is an effective method for providing terminal sterilization to biological tissue, but it is also reported to have deleterious effects on tissue mechanics in a dose-dependent manner. At irradiation ranges up to 25 kGy, a clear relationship between mechanical strength and dose has yet to be established. The aim of this study was to investigate the mechanical properties of bone and soft tissue allografts, irradiated on dry ice at a low absorbed dose (18.3-21.8 kGy) and a moderate absorbed dose (24.0-28.5 kGy), using conventional compressive and tensile testing, respectively. Bone grafts consisted of Cloward dowels and iliac crest wedges, while soft tissue grafts consisted of patellar tendons, anterior tibialis tendons, semitendinosus tendons, and fascia lata. There were no statistical differences in mechanical strength or modulus of elasticity for any graft irradiated at a low absorbed dose, compared to control groups. Also, bone allografts and two soft tissue allografts (anterior tibialis and semitendinosus tendon) that were irradiated at a moderate dose demonstrated similar strength and modulus of elasticity values to control groups. The results of this study support the use of low dose and moderate dose gamma irradiation of bone grafts. For soft tissue grafts, the results support the use of low dose irradiation.

Medium-term follow-up on use of freeze-dried, irradiated donor fascia for sacrocolpopexy and sling procedures.

The aim of this study was to document longer-term follow-up of patients in a previously reported series who underwent either sacrocolpopexy (SCP) or suburethral sling procedures utilizing freeze-dried, irradiated donor fascia. Subjects from the initial series of 67 SCPs and 35 slings were included in this retrospective chart review of postoperative follow-up where surgical follow-up longer than 3 months from the procedure was available. Subjects undergoing SCP were examined at the time of any clinical visit and their pelvic organ support evaluated utilizing the POP-Q system. The SCP procedure was considered to be unsuccessful if any anterior vaginal wall point (Aa or Ba) was at the hymen or beyond, or if the vaginal apical point (C or D) descended to a point at least halfway to the hymen from a position of perfect apical support. Subjects who did not return for clinical examination after their 3-month postoperative visit but who had been in telephone contact with the clinic stating that they had experienced symptomatic recurrence of their POP were also included as having unsuccessful SCP procedures. Those similarly in contact with the office by telephone, but not clinically examined, who indicated no subjective return of their POP, were coded as successful. The outcome of the sling procedure was primarily evaluated subjectively, with the patient indicating that stress incontinence symptoms were present or absent. Follow-up was available for 75 patients, who had undergone 54 SCP and 27 sling procedures (6 patients had undergone both SCP and sling procedures). When failure was defined according to any of the criteria listed in the methods section, 45 (83%) patients experienced SCP failure at a median of 12 months after surgery. A total of 14 (52%) sling procedures were failures, with recurrent SUI symptoms experienced from 2 weeks to 24 months (median 3 months) after the procedure. One year after surgery, 23 (43%) SCPs were known to be failures, and 11 (41%) slings were known to be failures. The remaining 13 (48%) slings were subjectively successful when last seen 7-51 months after surgery. We reoperated on 21 (40%) patients. At the time of repeat SCP (chosen by 16 patients) we found graft between the sacrum and vagina in just 3 patients (19%). The use of freeze-dried, irradiated donor fascia for both SCP and sling procedures was associated with an unacceptably high failure rate in our series.

Long-term results of frontalis suspension using irradiated, banked fascia lata.

This study was undertaken to study the long-term rate of recurrence of ptosis and other postoperative complications after frontalis suspension using banked irradiated fascia lata. One hundred thirty-two lids of 72 patients underwent frontalis suspension between 1980 and 1989. The preoperative diagnoses included severe congenital ptosis (83%), blepharophimosis (10%), third nerve palsy (4%), and chronic progressive external ophthalmoplegia (3%). The age at the time of surgery ranged from 5 months to 19 years, with an average of 3 years and 5 months. In 46 patients (64%), surgery was done before age 3 years. The follow-up time ranged from 6 to 15 years, with a mean and median of 10 years. Good to excellent lid height was achieved immediately after surgery in all but three patients. Recurrence of ptosis occurred in 20 cases (28%), and 28 lids (21%). The time to reoperation ranged from 1 to 7 years, with an average of 3 years. Sixteen patients (80%) with recurrence were younger than 3 years of age. Reaction to donor fascia lata occurred in only two patients (3%). Only one patient suffered from excessive exposure keratopathy and required revision of the sling. Banked fascia lata is easy to use and should be considered as an alternative suspensory material in children younger than 3 years of age with congenital ptosis. The long-term reoperation rate in this cohort of patients was higher than the 5% rate reported for autogenous fascia, but lower than that previously reported for banked fascia lata (50% at 8 years).