The antigenicity of fascia lata allografts

OBJECTIVE: To determine whether commercially available fascia lata allograft material contains donor antigens. MATERIALS AND METHODS: Human leukocyte antigens (HLA) class I and II were assessed in: (i) freeze-dried fascia lata allografts; (ii) a Tutoplast fascia lata graft (Mentor Urology, Santa Barbara, CA, USA); (iii) an acellular dermal graft; and (iv) a successful donor fascia sacrocolpopexy graft one year after implantation, using a polymerase chain reaction sequence-specific primer-based assay. RESULTS: The donor for both the freeze-dried fascia lata and Tutoplast fascia lata was fully HLA-typed. At one year after implantation, antigens from the implanted sacrocolpopexy graft matched the host blood antigens. The antigenicity of the acellular dermal graft could not be ascertained because this material interfered with the assay. CONCLUSION: Donor fascia lata grafts prepared by freeze-drying or by the Tutoplast technique retain donor antigens. The significance of this antigenicity is unknown. All donor antigens are replaced by host antigens after implantation.     

Prevention of Staphylococcus aureus graft infection by a new gelatin-sealed vascular graft prebonded with antibiotics

OBJECTIVE: The aim of this study was to evaluate the efficacy of a new gelatin-sealed graft prebonded with two antibiotics in resisting infection with Staphylococcus aureus (S aureus) A980142 after direct bacterial application in a dog model. METHODS: Twelve 6.0-mm polyester grafts were implanted in dogs end-to-end into the infrarenal aorta. The dogs were divided into two groups. A test group (n = 6) received experimental antibiotic-bonded gelatin-sealed knitted polyester grafts, loaded with two antibiotics, rifampin and tobramycin. A control group (n = 6) received commercial gelatin-sealed knitted polyester grafts. At the end of graft implantation, 50 mul of a 1.8 x 10(4) CFU/mL S aureus solution were instilled directly over the graft. One week after implantation, grafts were harvested with sterile technique. Quantitative cultures were obtained from all the harvested grafts. The results were expressed as colony-forming units per cm(2) of surface of the graft. Bacteriological study was also performed on various tissue samples. The chi(2) test was used to compare the culture proven infection of control and antibiotics-bonded grafts. RESULTS: Mean inoculum size was similar in the two groups of dogs. Five of the six control grafts grew S aureus A980142 at the time of graft removal, whereas none of the six antibiotic-bonded gelatin-sealed grafts were infected (P = .0192). None of the organ samples were infected in the group implanted with antibiotic-bonded grafts, whereas 15/34 samples grew S. aureus in the control group. CONCLUSION: These results indicate that this gelatin sealed graft prebonded with two antibiotics resists infection caused by S aureus graft contamination in a dog model.     

Triceps tendon fascia for collateral ligament reconstruction about the elbow: a clinical and biomechanical evaluation

In this article, we report on a cohort of patients who underwent elbow ligament reconstruction using triceps tendon fascia (TRI) and compare this alternative graft to a standard, the palmaris longus tendon (PL). The biomechanical properties of 8 TRI grafts were compared with those of 8 PL grafts, and 10 patients with TRI elbow ligament reconstructions were retrospectively clinically evaluated. Compared with PL, TRI had significantly more creep, but significantly less cross-sectional area and ultimate failure stress. Ultimate failure load and stiffness did not differ between grafts. Median (SD) postoperative Patient-Rated Elbow Evaluation score (0 = worst, 100 = best) was 79.3 (52). There was no statistical difference between preoperative and postoperative motion. All 10 patients had full triceps strength, and 9 of 10 elbows were stable on examination. With different graft morphology taken into account, PL had a statistically smaller cross-sectional area and double the ultimate failure stress. When compared using the proportions that would be used during surgical reconstruction, however, the grafts were comparable in ultimate failure strength and stiffness. It is unclear whether the statistically significant 0.8-mm difference in creep translates into clinical relevance. Clinically, patients reported good functional outcomes, motion, strength, and stability.     

Transplantation of Autologous Tissue Fragments into an e-PTFE Graft with Long Fibrils

Abstract: An expanded polytetrafluoroethylene (e-PTFE) graft with long fibrils transplanted with bone marrow showed rapid and uniform neointima formation in a dog study. The e-PTFE grafts (fibril length, 90 μm; 6 mm internal diameter; length, 6–8 cm) transplanted with autologous bone marrow were implanted in the abdominal aortae of 10 dogs and retrieved at 3 weeks and 3 months after implantation. Control e-PTFE grafts without bone marrow treatment were also implanted in the same manner in 8 dogs. Macroscopically the treated graft wall appeared red in color; however, there was no thrombus deposition on the surface. Light microscopic observation revealed that the treated grafts were completely lined with endothelial cells at 3 weeks. The neointima was uniform without intimai hyperplasia at the anastomotic sites.
Inside the graft wall many capillary blood vessels were observed. At 3 months moderate intimai hyperplasia throughout the graft with complete endothelialization was observed. In the control grafts, endothelialization was observed at the anastomotic sites; however, half of the other areas were covered with a fibrin layer devoid of endothelial cells even in the 3-month grafts. These results indicated that neointima formation was effectively accelerated with the autologous bone marrow transplantation, but moderate intimai hyperplasia throughout the graft was inevitable in e-PTFE grafts even after complete endothelialization.     

The effect of carbodiimide-derivatized hyaluronic acid and gelatin surface modification on peroneus longus tendon graft in a short-term canine model in vivo

PURPOSE: We have recently reported that application of carbodiimide-derivatized hyaluronic acid and gelatin (cd-HA gelatin) to a peroneus longus tendon graft increased tendon graft gliding ability and decreased work of flexion compared with untreated grafts in a canine model in vivo. In this study, we investigated the effect of this modification on adhesions, stiffness, strength of the distal attachment, and fibroblast count. METHODS: A total of 24 dogs were used for this study. The peroneus longus tendons of each hind leg were grafted into the 2nd and 5th digits of one forepaw in each dog. One peroneus longus tendon was treated with cd-HA gelatin prior to grafting, and the other one was immersed in 0.9% saline solution as a control. Animals were killed 1, 3, or 6 weeks postoperatively. RESULTS: The adhesion score of cd-HA gelatin-treated tendons was significantly less than that in the saline-treated tendons at all time points. There was no significant difference in the indentation stiffness between HA- and saline-treated grafts at any time point. For the ultimate force at the distal attachment, there was a significant difference among the time points, with a steady increase over time, but no significant difference between treated and control tendons at any time point. There was no significant difference in fibroblast count between treated and control tendons at any time point. CONCLUSIONS: Although gross adhesion formation was less, there was no significant difference in strength at the distal tendon-bone interface, cellularity, or tendon graft stiffness when comparing saline-treated and cd-HA gelatin-treated tendon grafts in vivo.     

Effect on vein graft intimal hyperplasia of nuclear factor-kB decoy transfection using the second generation of HVJ vector

AIM: Vein graft stenosis due to intimal hyperplasia (IH) is the main cause of graft failure. We examined possibilities of nuclear factor-kB (NF-kB) expression in vein grafts, and inhibitive effects of NF-kB decoy on the gene expression and subsequent vein graft IH. METHODS: Fifteen mongrel dogs underwent femoral artery replacement with autogenous vein grafts. Group I: grafts were retrieved at a predetermined time and subjected to NF-kB binding activity assay; Groups II and III: grafts were transfected with scrambled (II-a, III-a) or NF-kB (II-b, III-b) decoy using hemagglutinating virus of Japan envelope before implantation. Grafts were retrieved 7 days after implantation for evaluation of intercellular adhesion molecule-1 (ICAM-1) mRNA expression (Group II) and 4 weeks after implantation for comparison of IH by morphometric analysis (Group III). RESULTS: NF-kB binding activity was increased in a time-dependent manner, with a peak 2 days after implantation. The ratio between ICAM-1 and glyceraldehyde-3-phosphate dehydrogenase mRNA expression in II-b was significantly lower than that in II-a (0.347 +/- 0.07 versus 0.612+/-0.08; P = 0.047). The ratio of intimal cross-section area to luminal cross-section area of III-b was significantly lower than that of the III-a (0.096+/-0.03 versus 0.461+/-0.11; P = 0.048). CONCLUSION: NF-kB binding activity in vein grafts increases after implantation, and transfection of NF-kB decoy before implantation may reduce IH through the inhibition of ICAM-1 expression.     

Stent graft repair of visceral artery aneurysms

PURPOSE: The purpose of this study was to compare the efficacy of rifampin-bonded gelatin-sealed and silver acetate/collagen-coated knitted polyester prostheses for the prevention of bacteremic graft infection in an animal model. METHODS: Eighteen 6.0-mm polyester grafts (length, 5.0 cm) were implanted in dogs end-to-end into the infrarenal aorta. The dogs were divided into four groups as a function of type of prosthesis implanted. The dogs in groups I (n = 3) and II (n = 3) received control gelatin-sealed or collagen-coated polyester prostheses, respectively. In group III (n = 6), the dogs received rifampin-bonded gelatin-sealed polyester prostheses. In group IV (n = 6), the dogs received silver/collagen-coated polyester prostheses. Two days after implantation, the grafts were challenged with 6 x 10(9) Staphylococcus aureus intravenously. One week after implantation, the grafts were harvested with sterile technique. Quantitative cultures were obtained from all the harvested grafts. The results were expressed as colony-forming units per cm(2) of graft material. Bacteriologic study was also performed on various tissue samples. The chi(2) test was used to compare the culture proven infection of control and antimicrobial grafts. RESULTS: All the control grafts were infected with S aureus at the time of removal. Five of the six silver/collagen-coated grafts were infected, whereas none of the six rifampin-bonded gelatin-sealed grafts grew S aureus (P <.01). There was no significant difference in the number of positive culture results of organ samples between the different groups of dogs. CONCLUSION: These results indicate that rifampin-bonded gelatin-sealed polyester grafts are significantly more resistant to bacteremic infection than are silver/collagen-coated polyester grafts in a highly challenging model.     

Precultivation of engineered human nasal cartilage enhances the mechanical properties relevant for use in facial reconstructive surgery

OBJECTIVE: To investigate if precultivation of human engineered nasal cartilage grafts of clinically relevant size would increase the suture retention strength at implantation and the tensile and bending stiffness 2 weeks after implantation. SUMMARY BACKGROUND INFORMATION: To be used for reconstruction of nasal cartilage defects, engineered grafts need to be reliably sutured at implantation and resist to bending/tension forces about 2 weeks after surgery, when fixation is typically removed. METHODS: Nasal septum chondrocytes from 4 donors were expanded for 2 passages and statically loaded on 15 x 5 x 2-mm size nonwoven meshes of esterified hyaluronan (Hyaff-11). Constructs were implanted for 2 weeks in nude mice between muscle fascia and subcutaneous tissue either directly after cell seeding or after 2 or 4 weeks of preculture in chondrogenic medium. Engineered tissues and native nasal cartilage were assessed histologically, biochemically, and biomechanically. RESULTS: Engineered constructs reproducibly developed with culture time into cartilaginous tissues with increasing content of glycosaminoglycans and collagen type II. Suture retention strength was significantly higher (3.6 +/- 2.2-fold) in 2-week precultured constructs than in freshly seeded meshes. Following in vivo implantation, tissues further developed and maintained the original scaffold size and shape. The bending stiffness was significantly higher (1.8 +/- 0.8-fold) if constructs were precultured for 2 weeks than if they were directly implanted, whereas tensile stiffness was close to native cartilage in all groups. CONCLUSION: In our experimental setup, preculture for 2 weeks was necessary to engineer nasal cartilage grafts with enhanced mechanical properties relevant for clinical use in facial reconstructive surgery.     

Evaluation of three techniques for documenting Staphylococcus epidermidis vascular prosthetic graft infections

Staphylococcus epidermidis (S. epidermidis) vascular prosthetic graft infections are notoriously hard to detect. Three different techniques of determining whether vascular prosthetic grafts were infected using a dog model were evaluated. Aortic angiograms were compared with nuclear magnetic resonance (NMR) imaging and systemic norepinephrine (NE) kinetics to determine if either newer technique would be more reliable than standard angiograms. Twelve dogs were randomized to control (n = 6) or infected groups (n = 6). All dogs had a 5 cm section of their infrarenal aorta replaced with knitted Dacron vascular prosthetic graft. The grafts in the infected group were contaminated by soaking them in a broth containing S. epidermidis. NE production and clearance rates were calculated for all animals after an infusion of 3H-NE using the steady-state radionuclide tracer methodology. One week following graft insertion, dogs were reanesthetized, and the 3H-NE infusion and measurements were repeated. Standard angiograms and NMR imaging were also performed. Once all tests were performed, the prosthetic grafts were removed for cultures. Comparisons between the initial and final norepinephrine measurements for each group were made using the nonparametric Wilcoxon two-sample test, while comparisons between the groups were made by chi square or the Student's t test. Angiogram results were similar for control and infected animals. Angiograms missed disruption of the proximal anastomosis found in three of the six infected dogs at graft removal. None of the six control animals, while five of the six infected animals, had localized areas of high signal intensity on NMR imaging (P less than 0.01) suggesting abscess formation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Structural properties of sutures used in anchoring multistranded hamstrings in anterior cruciate ligament reconstruction: a biomechanical study.

Sutures are frequently used in anchoring hamstring or quadriceps tendon grafts in cruciate ligament reconstruction. Trumpet like widening of the femoral bone canal was found in patients having had anterior cruciate ligament reconstruction with hamstring autograft. We investigated 5-mm Polylene tape (Genzyme, Boston, MA) and Mersilene tape (Ethicon, Somerville, NJ) as well as No. 6 Ethibond sutures (Ethicon) for ultimate load, stiffness, and elongation under tension of 50 N, 150 N, 250 N, and ultimate load. The Mersilene and Polylene tapes were tested in single loops and Ethibond in double loops having a length of 30 mm. The length is similar to that used intraoperatively for the graft fixation. The suture materials were loaded using a material testing machine at a strain rate of 60 mm/min. The ultimate loads of the loops with knots were 474 N +/-24.7 N for Polylene, 437 N +/-38.2 N for Mersilene, and 338 N +/-16.8 N for Ethibond, and was statistically significant (analysis of variance [ANOVA], P<.05). The elongation under a tension load of 50 N was similar for Ethibond (1.2+/-0.216 mm) and Polylene (1.3+/-0.32 mm). Mersilene (1.7+/-0.34 mm) showed an increased elongation (ANOVA, P=.03). The stiffness for Ethibond was 37.1+/-2.7 N/mm, for Mersilene 38.4+/-3.8 N/mm, and for Polylene was 47+/-3.1 N/mm. The Polylene tape appears to be the most suitable material in terms of strength and stiffness. Nevertheless, the stiffness of all the tested materials is greatly inferior to the stiffness of the commonly used grafts. We believe that a stiffer graft construct might reduce motion during the early period of ingrowing.     

The enhancement of fixation of a porous-coated femoral component by autograft and allograft in the dog

Revision total arthroplasty of the hip, without cement, was done in dogs to compare the abilities of autologous grafts and allografts of bone to enhance histological ingrowth of bone and biomechanical strength. Six weeks after primary total hip arthroplasty with cement, the femoral component was revised to a titanium fiber-metal prosthesis. On the basis of the type of graft that was impacted into the voids around the ingrowth surface at revision, three study groups were created: no graft (control), four dogs; fresh autograft, six dogs; and frozen allograft, six dogs. Twelve weeks after revision, histological analysis revealed the greatest amount of ingrowth proximally in the grafted specimens. A mean of 22.3 per cent ingrowth was observed in the dogs that had an autograft; this was not significantly different from the mean of 17.5 per cent in those that had an allograft. The non-grafted specimens showed little ingrowth, the values being significantly less than those for the grafted specimens. Push-out testing showed greater ultimate shear strength proximally than distally in the grafted specimens, and at the proximal level there was a significant difference between the group that had an autograft and the control group (mean, 4.03 and 1.22 megapascals, respectively). Ultimate strength correlated positively with ingrowth of bone (r = 0.82). Radiographically, subsidence of the components and lucent lines were observed more frequently in the nongrafted specimens, and if both were present, significantly less ingrowth of bone and strength were observed.     

Differential effects of a gram-negative and a gram-positive infection on autogenous and prosthetic grafts

A canine model was developed to study the differential response of a gram-negative and a gram-positive bacterial infection on autogenous and prosthetic grafts. After replacing segments of the femoral arteries of 15 dogs with autogenous vein in one groin and polytetrafluoroethylene in the contralateral groin, 10(8) colony-forming units of nonmucin-producing Staphylococcus epidermidis (five dogs), Pseudomonas aeruginosa (five dogs), or sterile saline solution (five dogs) were directly inoculated onto the grafts. The grafts were examined 7 to 10 days after implantation. None of the control dogs exhibited inflammatory signs, and no grafts or anastomoses disrupted. S. epidermidis was unrecoverable from either graft material in any of the animals, although histologic evaluation confirmed neutrophils and bacteria in four of five animals in the vein and polytetrafluoroethylene groups. No dog inoculated with S. epidermidis had graft or anastomotic disruption. By contrast, P. aeruginosa was recovered from both types of grafts in all inoculated animals. Neutrophils, bacteria, and microabscesses were observed in all of these animals. In addition, three of five polytetrafluoroethylene grafts and all five vein grafts disrupted either at the anastomoses or in the body of the vein graft. Therefore S. epidermidis is a less virulent organism that may persist in graft walls despite negative cultures, whereas P. aeruginosa is a highly virulent organism that can disrupt native artery, vein grafts, and anastomoses. The graft material appears to be less important than the bacteria in determining the outcome of infection.     

Nonthrombogenic Polymer Vascular Prosthesis

Abstract: Although many synthetic vascular grafts have been developed and evaluated experimentally or clinically, none of them have met long-term patency when applied as a small diameter vascular substitute. We have recently developed a small caliber vascular graft (3 mm i.d.) using a nonthrombogenic polymer coating. The graft consists of three layered structures: Dacron for the outer layer, polyurethane in the middle layer, and a HEMA/ styrene block copolymer (HEMA-st) coating for the inner layer. HEMA-st is an amphiphilic block copolymer composed of 2-hydroxyethyl methacrylate and styrene which has demonstrated improved blood compatibility over existing biomedical polymers in both in vitro and ex vivo experiments. Ten grafts were evaluated in a dog bilateral carotid replacement model. The grafts were electively retrieved at 7, 14, 30, 92, and 372 days after implantation.
All grafts were patent without detectable thrombi along the graft length including anastomotic sites. Scanning electron micrographs of retrieved graft lumen showed fairly clean surfaces covered with a homogenous protein-like layer without microthrombi or endothelial cell lining. The thickness of the surface protein layer measured by a transmission electron microscopy was what can be described as monolayer protein adsorption regardless of implantation periods of as much as 372 days. A stable monolayer adsorbed protein layer formed on HEMA-st surfaces demonstrated nonthrombogenic activities in vivo and secure long-term patency of small caliber vascular grafts with the absence of an endothelial cell lining.     

Viscoelasticity and temperature variations decrease tension and stiffness of hamstring tendon grafts following anterior cruciate ligament reconstruction

BACKGROUND: Hamstring tendon grafts used for anterior cruciate ligament reconstruction are typically harvested early in the surgical procedure and are preconditioned prior to reimplantation. Postoperatively, the grafts undergo stress relaxation and warm from the temperature of the operating room to body temperature. The hypothesis of this study was that the tension within semitendinosus and gracilis tendon grafts and the stiffness of the grafts significantly decrease postoperatively because of both stress relaxation and an increase in temperature. METHODS: Double-strand grafts were created from six semitendinosus tendons and six gracilis tendons harvested from cadaver specimens. The grafts were loaded to 65 N while at operating-room temperature (20 degrees C). After fifteen minutes of stress relaxation, graft tension was measured and the grafts were stretched by 0.1 mm to determine stiffness. The tension and stiffness measurements represented graft properties immediately following reconstruction. Additional tension and stiffness measurements were made following three hours of stress relaxation and after increasing the temperature to the body temperature at the knee (34 degrees C). Both types of graft were examined for differences in stiffness and tension due to stress relaxation and the temperature increase. RESULTS: For both types of graft, the tension and stiffness decreased following stress relaxation to approximately 50% and 80%, respectively, of the value immediately after reconstruction. Increasing the temperature decreased the tension and stiffness further to approximately 40% and 70%, respectively, of the value after reconstruction for both types of graft. All changes in tension and stiffness were significant (p < 0.01). CONCLUSIONS: Graft tension and stiffness achieved immediately following reconstruction are not maintained postoperatively because of stress relaxation and a temperature increase. This could lead to increased knee laxity.     

Vaginal Erosion of Cadaveric Fascia Lata following Abdominal Sacrocolpopexy and Suburethral Sling Urethropexy

The aim of this paper is to report vaginal erosion of cadaveric fascia lata used for abdominal sacrocolpopexy and suburethral sling urethropexy. The charts of patients who underwent abdominal sacrocolpopexy or suburethral sling urethropexy between March 1994 and February 1999 were reviewed for perioperative data. In 47 cases of abdominal sacrocolpopexy or suburethral sling, 32 utilized cadaveric fascia lata, with 11 for sacrocolpopexy and 22 for suburethral sling. Vaginal erosion of cadaveric fascia lata graft was noted in 5 (23%) following sling procedure and 3 (27%) following sacrocolpopexy, diagnosed a mean of 36.8 days (t 7.1, range 27–45) following surgery. These women were treated conservatively with estrogen vaginal cream, and both vaginal and oral antibiotics. Four of the 8 (50%) underwent excision of the exposed graft and reapproximation of the vaginal edges under local anesthesia, whereas the remainder responded to medical therapy alone. None of the patients experienced recurrence of vaginal vault prolapse or urinary incontinence following graft erosion. Comparison of women with vaginal erosion of cadaveric fascia lata to those without revealed an association with perioperative febrile morbidity (P = 0.04), but not with age, hormonal or insurance status, body mass index, history of diabetes mellitus or smoking, length of surgery, estimated blood loss, change in hematocrit, or other perioperative complications. Vaginal erosion of cadaveric fascia lata utilized for abdominal sacrocolpopexy and suburethral sling was noted in 25% of our patients and may have an infectious etiology. Conservative treatment with antibiotics and estrogen is effective, but removal of exposed graft with vaginal closure may be necessary.     

An experimental study of the strength in arterial prosthetic anastomoses: relationship between anastomotic tensile strength and its organization]

Five types of 6-mm diameter arterial prostheses, i.e.m woven Teflon, woven Dacron, velour woven Dacron, velour knitted Dacron and expanded polytetrafluoroethylene (E-PTFE), were studied in the dog to assess anastomotic tensile strength and its organization. Five types of composite grafts, about 3.0cm in length, were implanted in the abdominal aorta of fifty-two adult mongrel dogs using absorbable polyglycolic acid suture. At 16 weeks after the implantation, if the composite graft was patent, tensile strength of the bilateral anastomoses were measured and its organizations were examined microscopically. The mean forces required to disrupt the anastomoses of velour woven Dacron, velour knitted Dacron and E-PTFE were greater than those of woven Teflon and woven Dacron. At the disrupted sites of woven Teflon and woven Dacron, which were non-velour grafts, fibrous outer sheath were remarkably separated from the grafts. This results indicate that organization and fixation of fibrous outer sheath are the most important factors in the strength of arterial prosthetic anastomoses and velour grafts have superiority over non-velour grafts. The organization of E-PTFE was poor, but its tensile strength was equal to velour grafts. It is considered E-PTFE has an advantage due to non-crimped structure and requires further evaluation over longer period.     

Effects of implanted Doppler flowmeters on femoral vein autografts.

Thirteen femoral vein autografts were placed into the corresponding ipsilateral femoral arteries of 8 mongrel dogs. Cuff-type Doppler (ultrasonic) flowmeters were placed around six of the grafts. None of the vessels thrombosed. Blood flow velocities were measured in all vessels up until the time of sacrifice (mean 95 +/- 5 days after surgery) or accidental death (one dog, 49 days after surgery). The only case of graft failure was attributed to infection at the flowmeter site. With this single exception, the vein grafts exhibited uniformity in histological appearance from dog to dog. These data suggest that implantation of properly designed Doppler flow transducers may have clinical applications. This technique permits continuous or intermittent assessment of blood flow characteristics through a graft without additional trauma or cost to the patient. It is free of the many inherent disadvantages of chronically implanted electromagnetic flowmeters and may negate the need in some instances for followup angiographic studies.     

In vitro comparison of tension and stiffness between hamstring tendon and patella tendon grafts

Following anterior cruciate ligament reconstruction, grafts relax and warm from the temperature of the operating room to body temperature. The current study compared graft tension and stiffness between patella tendon and hamstring tendon grafts. Six quadruple strand hamstring tendon grafts and six patella tendon grafts were preconditioned and loaded to 105 N while at 20°C. Graft tension and stiffness were measured after 15 min, after an additional 4 h, and after increasing the temperature to 34°C. A two‐way repeated‐measures analysis of variance and a post hoc test were used to compare the measurements between the two types of graft and identify significant (p < 0.05) changes for each type of graft. Tension was significantly larger for the patella tendon grafts, although the stiffness values were not significantly different (p > 0.8). For both types of graft, tension and stiffness decreased significantly with time and the temperature increase. The lowest tension and stiffness measurements were 50 ± 11 N and 129 ± 35 N/mm, respectively, for the patella tendon grafts, compared to 18 ± 5 N and 115 ± 11 N/mm, respectively, for the hamstring tendon grafts. Both types of graft lose tension to relaxation and a temperature increase, but the tension loss is larger for hamstring tendon grafts. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1506–1511, 2008     

Infected abdominal sacrocolpopexies: diagnosis and treatment

The abdominal sacrocolpopexy is an excellent procedure to surgically treat vaginal vault prolapse. A synthetic graft is often used to support the vaginal apex, but has the potential to become infected or erode, requiring its removal or revision. The purpose of this paper is to report our experience in the management of patients with infected synthetic grafts after abdominal sacrocolpopexy. A review of the patient databases from three specialty gynecology centers was performed from March 1996 to June 2002. Only patients with an infected graft after an abdominal sacrocolpopexy were included in the study; patients with either suture or graft erosion responding to conservative treatment were excluded. Twenty-two women, ages 37-73 years, developed infection of the synthetic graft after an abdominal sacrocolpopexy (1-60 months after their initial surgery, mean 8.8 months). The infected materials included polytetrafluoroethylene (PTFE, Goretex, n =15) and polypropylene (n=7). Nine of the 15 PTFE meshes and four of the seven polypropylene meshes were placed at the time of a contaminated case (abdominal hysterectomy [n=12], colon resection [n=1]). Eighteen (82%) of the infected grafts involved braided permanent suture to attach the graft to the vaginal wall, monofilament/non-braided permanent suture was used in three patients, and suture type could not be determined in one. All graft removals were attempted vaginally, and this was successful in 16 cases (73%). Two patients experienced significant bleeding: the first patient required an emergency laparotomy and the second patient's bleeding was controlled with packing. A rectovaginal fistula occurred 3 weeks postoperatively in one patient. Synthetic graft infection should be considered as the differential diagnosis in a patient who has undergone an abdominal sacrocolpopexy. Transvaginal removal is preferred, but is fraught with potentially serious complications. The use of braided permanent sutures to affix the graft to the vagina may be associated with mesh infections.     

High-porosity expanded polytetrafluoroethylene grafts for thoracic vena cava replacement with or without an omentum wrap

We previously reported that, in a short-term thoracic inferior vena cava (IVC) replacement, a high-porosity expanded polytetrafluoroethylene (ePTFE) graft (fibril length 60 μm) performed well without altering the short-term patency, and that the healing of the high-porosity ePTFE graft was accelerated by an omentum wrap. The purpose of this study was to examine the long-term performance of the high-porosity ePTFE graft with or without an omentum wrap. Eighteen grafts were placed as a thoracic IVC replacement in dogs. Nine of the grafts were wrapped in an omental pedicle flap while the other 9 were not. At 1 month and 6 months, the grafts were harvested and examined for a pathological analysis. During the observation period, one dog died of a viral infection, while the other 17 dogs survived. At 1 month and 6 months, the patency rates of the 17 grafts were 100% regardless of the presence or absence of an omentum wrap. The healing of the grafts without omentum wrap was incomplete 6 months after implantation; granulation tissue was present in the center of the pseudointima. The grafts healed completely by the addition of an omentum wrap. Our data suggest that, with an omentum wrap, the high-porosity ePTFE graft is fully expected to show a good long-term function. Received: January 5, 1999 / Accepted: November 11, 1999