Study on microvascular anastomosis of arteries with absorbable polyglyconate suture

Resorbable self-locking device for canine lung lobectomy: A clinical and experimental study

OBJECTIVE

To test the feasibility of a resorbable self-locking device for sealing of lung tissue in lung lobectomy in experimental dogs and dogs with pulmonary mass, and to study its resorption with CT.

STUDY DESIGN

Experimental study and clinical case series.

ANIMALS

Five beagles in the experimental group; six canine patients with a pulmonary mass in the clinical group.

METHODS

In both groups, an intercostal incision into thorax was performed. A resorbable self-locking device, LigaTie, was applied at the hilum of left cranial lobe in the experimental group and the affected lobe in the clinical group. Each lobe was removed by cutting the tissue just distal to the device. Video-assisted thoracic surgery was used in the experimental group; postoperative diagnostic imaging was repeated monthly until the device was not apparent on CT.

RESULTS

Application of LigaTie was feasible for lung lobectomy in all dogs. The device enabled en bloc ligation of the hilum of the affected lobe including the pulmonary arteries and veins and lobular bronchus. No air leakage from the resection stump was observed in any dog. Trace of the device on CT images gradually decreased and was undetectable at 4 months postoperatively in experimental dogs.

CONCLUSION

This study suggested that the resorbable self-locking device may be used for sealing of airways in complete lung lobectomy.

CLINICAL RELEVANCE

The resorbable self-locking device is suggested to be useful for canine lung lobectomy and may facilitate thoracoscopic lung lobectomy. Further investigations on its clinical application in small animal surgery are warranted.

Comparison of macroscopic resorption time for a self-locking device and suture material in ovarian pedicle ligation in dogs

A resorbable self-locking device (LigaTie) was developed to enable safe and easy surgical ligation of blood vessels. The aim of this study was to compare the long-term in vivo resorption of the device to a commercially available suture of equivalent material (Maxon) following ovarian pedicle ligation. After ovariohysterectomy follow-up ultrasound examinations were performed monthly on 21 dogs ligated with the device and 22 dogs ligated with the suture material until no hyperechoic remnants, acoustic shadowing or local tissue reactions were detected. In both groups, the ovarian pedicles gradually decreased in size. Ligation material was considered macroscopically resorbed when ultrasound showed no signs of the device or suture, ovarian pedicle or tissue reaction. Macroscopic resorption had occurred without signs of complications and was complete by four months for sutures and 5.5 months for the device. The results show that resorption time in vivo for the resorbable self-locking device is mildly longer than suture of the same material and that no complications of device resorption were detected, supporting that the resorbable self-locking device is safe for in vivo use.

Nanofiber-based sutures induce endogenous antimicrobial peptide

AIM

The aim of this study was to develop nanofiber-based sutures capable of inducing endogenous antimicrobial peptide production.

METHODS

We used co-axial electrospinning deposition and rolling to fabricate sutures containing pam3CSK4 peptide and 25-hydroxyvitamin D₃ (25D₃).

RESULTS

The diameters and mechanical properties of the sutures were adjustable to meet the criteria of United States Pharmacopeia designation. 25D₃ exhibited a sustained release from nanofiber sutures over 4 weeks. Pam3CSK4 peptide also showed an initial burst followed by a sustained release over 4 weeks. The co-delivery of 25D₃ and pam3CSK4 peptide enhanced cathelicidin antimicrobial peptide production from U937 cells and keratinocytes compared with 25D₃ delivery alone. In addition, the 25D₃/pam3CSK4 peptide co-loaded nanofiber sutures did not significantly influence proliferation of keratinocytes, fibroblasts, or the monocytic cell lines U937 and HL-60.

CONCLUSION

The use of 25D₃/pam3CSK4 peptide co-loaded nanofiber sutures could potentially induce endogenous antimicrobial peptide production and reduce surgical site infections.

Suture materials affect peri-implant bone healing and implant osseointegration

The aim of this study was to evaluate the effects of the remnants of two suture materials on osseointegration of titanium implants in a rabbit tibial model. Calibrated defects were prepared in the tibia of five Chinchilla rabbits. Filaments of nonresorbable (NR) nylon or resorbable (R) chitosan were placed at the bone to implant interface, whereas control sites had no suture material. After a healing period of 4 weeks, a pull-out test procedure was performed followed by enzymatic analyses of the wound fluid and relative quantification of mRNA levels for bone-related and cytokine markers from the peri-implant bone. A trend toward a reduced pull-out force was observed in the NR group (NR: 23.0 ± 12.8 N; R: 33.9 ± 11.3 N; control: 33.6 ± 24.0 N). Similarly, the bone resorption marker vacuolar type H+-ATPase was increased in the NR group compared with that in the control group (P = 0.041). The R group showed trends for lower alkaline phosphatase activity and osteocalcin expression and higher total protein content and RNA compared with the control group. In this submerged healing model, peri-implant bone healing was marginally affected by the two suture materials tested. However, there was a tendency toward better osseointegration and lower expression of bone resorption markers in the R group compared with the control group.

Twisting electrospun nanofiber fine strips into functional sutures for sustained co-delivery of gentamicin and silver

Surgical site infections (SSIs) represent the most common nosocomial infection among surgical patients. In order to prevent SSIs in a sustained manner and lessen side effects, we developed a twisting method for generation of nanofiber-based sutures capable of simultaneous delivery of silver and gentamicin. The prepared sutures are composed of core-sheath nanofibers with gentamicin/pluronic F127 in the core and silver/PCL in the sheath produced by co-axial electrospinning. The diameters of obtained sutures range from ~80 μm to ~1.2 mm. The in vitro release profiles of silver and gentamicin exhibit an initial burst followed by a sustained release over 5 weeks. The co-encapsulated sutures were able to kill bacteria much more effectively than gentamicin or silver alone loaded nanofiber sutures, without showing obvious impact on proliferation and migration of dermal fibroblasts and keratinocytes. The gentamicin and silver co-loaded PCL nanofiber sutures may hold great potential for prevention of SSIs.

Review Paper: Absorbable Polymeric Surgical Sutures: Chemistry, Production, Properties, Biodegradability, and Performance

Among biomaterials used as implants in human body, sutures constitute the largest groups of materials having a huge market exceeding $1.3 billion annually. Sutures are the most widely used materials in wound closure and have been in use for many centuries. With the development of the synthetic absorbable polymer, poly(glycolic acid) (PGA) in the early 1970s, a new chapter has opened on absorbable polymeric sutures that got unprecedented commercial successes. Although several comparative evaluations of suture materials have been published, there were no serious attempts of late on a comprehensive review of production, properties, biodegradability, and performance of suture materials. This review proposes to bring to focus scattered data on chemistry, properties, biodegradability, and performance of absorbable polymeric sutures.

Results of an observational study in carotid surgery using absorbable suture material

BACKGROUND

Absorbable sutures are not well accepted for reconstruction in high-pressure arterial segments because the suture line might break and aneurysmal changes could develop. This hypothesis was checked in the clinical setting of carotid surgery.

METHODS

The morphology of the carotid artery was evaluated by color-coded ultrasound in four groups of patients: group A, 25 patients who underwent standard carotid endarterectomy and patchplasty, including a transverse plication for which absorbable sutures had been used; group B, 10 patients who underwent eversion endarterectomy and reinsertion using absorbable sutures; group C, 15 patients who underwent standard carotid endarterectomy and patchplasty without a transverse placation; group D, 20 patients who suffered from atherosclerotic disease but did not have previous carotid surgery or other carotid pathology. All operations had been performed at least 3 years earlier than the actual examination.

RESULTS

Along the internal carotid artery, where an aneurysmal change would have been expected to occur, no differences in absolute size or calculated elliptical cross-sectional vessel area were found. Patients after eversion endarterectomy did not show signs of aneurysmal changes in the area of reinsertion at the carotid bifurcation.

CONCLUSIONS

Even in the long-term, for this group of patients, no significant aneurysmal changes of arterial reconstructions in carotid surgery performed with absorbable sutures were observed.

Comparison of absorbable and nonabsorbable sutures for microsurgical vasovasostomy in rats

OBJECTIVES

At least 12% of initially patent vasovasostomies (VVs) shut down. Currently, only nonabsorbable sutures are used for VV. A synthetic, slowly absorbing, monofilament polyglactin suture has been developed that retains tensile strength for up to 6 months. We performed a prospective controlled randomized study comparing absorbable and nonabsorbable sutures for rat VVs.

METHODS

Bilateral microsurgical VV was performed in three groups of 36 Wistar male rats, with 10-0 nylon, 10-0 polypropylene, and 10-0 polyglactin sutures. Twelve control rats underwent sham operations. Three rats in each group were killed at 2, 6, 12, and 24 weeks. The abdominal end of the vas deferens was transected and the intraluminal fluid examined microscopically for presence of sperm. The segment of the vas deferens containing the anastomosis was excised. Fluid from the testicular end was examined for sperm to confirm spermatogenesis. Patency was confirmed by an antegrade indigo carmine vasogram of the anastomotic segment. Segments were randomly sent for histologic or tensile strength evaluation.

RESULTS

The mean tensile strength of the anastomoses performed with nylon was slightly higher than in polypropylene and polyglactin sutures, although the difference was not statistically significant. Polyglactin consistently maintained tensile strength throughout 6 months without significant fluctuations. The mean patency rate in the polyglactin group was 96%, in nylon 81%, and in polypropylene 61%. Although polyglactin had a consistently higher patency rate compared with nonabsorbable sutures, the difference was not statistically significant (P = 0.11) but indicated a strong trend. The occurrence of microscopic sperm granuloma, muscle layer injuries, intimal fibrosis, and adventitial fibrosis of the vas deferens was not significantly different between suture types.

CONCLUSIONS

The three suture materials appear equivalent with respect to overall tensile strength of anastomosis; with histologic evaluation, the trend was toward better patency with polyglactin. Polyglactin 10-0 microsurgical suture is a viable alternative to nonabsorbable sutures in microsurgical VVs, although further studies are indicated to assess long-term results.