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PubMed1996

Effect of peripheral suture depth on strength of tendon repairs.

The peripheral suture in flexor tendon repairs was originally introduced to "tidy up" the repair site and to improve gliding after core suture placement. More recently, it has been proposed that the peripheral suture can be an important structural component of tendon repair; yet, the effect of peripheral suture technique as an independent factor on the strength of the tendon repair has had little attention. We proceeded to determine whether differing levels of penetration of the tendon by the peripheral suture significantly affect the strength of the repair. We performed tensile tests on two groups of fresh frozen cadaver flexor digitorum superficialis tendons that had lacerations repaired by modified Kessler core sutures: one group had supplemental superficial peripheral sutures while the other group had supplemental deep (half the depth to the center of the tendon) peripheral sutures. The mean failure load of the deep peripheral suture group (38.96 N) was almost 80% greater than that of the superficial suture group (21.68 N). This increased strength may be due to an improved tendon-suture interface, with the deep peripheral suture acting as an auxiliary core suture. Our results with deep peripheral sutures, a simple technique based on a modification of commonly employed suture patterns, demonstrate substantially improved repair strength. This suture has the potential to be used in conjunction with early active finger motion rehabilitation program after flexor tendon repair.

Biomechanical Phenomena↗
PubMed2004

Apoptosis in a rodent model of cranial suture fusion: in situ imaging and gene expression analysis.

Craniosynostosis, the premature fusion of cranial sutures, is one of the most common craniofacial anomalies, with a reported incidence of up to one in 2500 live births. Despite its prevalence, the cause of craniosynostosis remains unknown. Previously, apoptosis has been postulated to be a contributing factor in the pathogenesis of craniosynostosis, although the role of programmed cell death in cranial sutures is poorly understood. To address this problem, the authors used an established rodent model of posterior-frontal suture fusion and sagittal suture patency to globally examine apoptosis in cranial sutures. Apoptosis was evaluated by systemically coinjecting Sprague-Dawley rats with both fluorescent and technetium-99m-labeled annexin V at time points before, during, and after the period of predicted posterior-frontal suture fusion to determine the magnitude and time course of overall apoptotic activity in both fusing and patent sutures. Using these novel in situ imaging techniques, the authors observed a significant increase in the overall levels of apoptosis in both the posterior-frontal and sagittal suture complexes during the period of predicted posterior-frontal suture fusion. To further explore this increase in apoptotic activity, they used microarray technology to study apoptosis-related genes within the suture complex. Interestingly, there was activation of distinct apoptotic pathways in the posterior-frontal and sagittal sutures during the period of predicted posterior-frontal suture fusion. Whereas increased transcription of genes associated with the mitochondria-mediated apoptotic pathway occurred in the posterior-frontal suture during fusion, activation of genes associated with the death receptor-mediated apoptotic pathway predominated in the patent sagittal suture during the same time period. These data suggest that although overall apoptotic activity in rat patent and fusing sutures is similar, the pathways mediating apoptosis within each suture are distinct.

Animals↗
PubMed1998

FGF-, BMP- and Shh-mediated signalling pathways in the regulation of cranial suture morphogenesis and calvarial bone development.

The development of calvarial bones is tightly co-ordinated with the growth of the brain and needs harmonious interactions between different tissues within the calvarial sutures. Premature fusion of cranial sutures, known as craniosynostosis, presumably involves disturbance of these interactions. Mutations in the homeobox gene Msx2 as well as the FGF receptors cause human craniosynostosis syndromes. Our histological analysis of mouse calvarial development demonstrated morphological differences in the sagittal suture between embryonic and postnatal stages. In vitro culture of mouse calvaria showed that embryonic, but not postnatal, dura mater regulated suture patency. We next analysed by in situ hybridisation the expression of several genes, which are known to act in conserved signalling pathways, in the sagittal suture during embryonic (E15-E18) and postnatal stages (P1-P6). Msx1 and Msx2 were expressed in the sutural mesenchyme and the dura mater. FGFR2(BEK), as well as Bmp2 and Bmp4, were intensely expressed in the osteogenic fronts and Bmp4 also in the mesenchyme of the sagittal suture and in the dura mater. Fgf9 was expressed throughout the calvarial mesenchyme, the dura mater, the developing bones and the overlying skin, but Fgf4 was not detected in these tissues. Interestingly, Shh and Ptc started to be expressed in patched pattern along the osteogenic fronts at the end of embryonic development and, at this time, the expression of Bmp4 and sequentially those of Msx2 and Bmp2 were reduced, and they also acquired patched expression patterns. The expression of Msx2 in the dura mater disappeared after birth. FGF and BMP signalling pathways were further examined in vitro, in E15 mouse calvarial explants. Interestingly, beads soaked in FGF4 accelerated sutural closure when placed on the osteogenic fronts, but had no such effect when placed on the mid-sutural mesenchyme. BMP4 beads caused an increase in tissue volume both when placed on the osteogenic fronts and on the mid-sutural area, but did not effect suture closure. BMP4 induced the expression of both Msx1 and Msx2 genes in sutural tissue, while FGF4 induced only Msx1. We suggest that the local application of FGF on the osteogenic fronts accelerating suture closure in vitro, mimics the pathogenesis of human craniosynostosis syndromes in which mutations in the FGF receptor genes apparently cause constitutive activation of the receptors. Taken together, our data suggest that conserved signalling pathways regulate tissue interactions during suture morphogenesis and intramembranous bone formation of the calvaria and that morphogenesis of mouse sagittal suture is controlled by different molecular mechanisms during the embryonic and postnatal stages. Signals from the dura mater may regulate the maintenance of sutural patency prenatally, whereas signals in the osteogenic fronts dominate after birth.

Animals↗
PubMed2000

A molecular analysis of the isolated rat posterior frontal and sagittal sutures: differences in gene expression.

Although it is one of the most commonly occurring craniofacial congenital disabilities, craniosynostosis (the premature fusion of cranial sutures) is nearly impossible to prevent because the molecular mechanisms that regulate the process of cranial suture fusion remain largely unknown. Recent studies have implicated the dura mater in determining the fate of the overlying cranial suture; however, the molecular biology within the suture itself has not been sufficiently investigated. In the murine model of cranial suture fusion, the posterior frontal suture is programmed to begin fusing by postnatal day 12 in rats (day 25 in mice), reliably completing bony union by postnatal day 22 (day 45 in mice). In contrast, the sagittal suture remains patent throughout the life of the animal. Using this model, this study sought to examine for the first time what differences in gene expression--if any--exist between the two sutures with opposite fates. For each series of experiments, 35 to 40 posterior frontal and sagittal suture complexes were isolated from 6-day-old Sprague-Dawley rat pups. Suture-derived cell cultures were established, and ribonuicleic acid was derived from snap-frozen, isolated suture tissue. Results demonstrated that molecular differences between the posterior frontal and sagittal suture complexes were readily identified in vivo, although these distinctions were lost once the cells comprising the suture complex were cultured in vitro. Hypothetically, this change in gene expression resulted from the loss of the influence of the underlying dura mater. Significant differences in the expression of genes encoding extracellular matrix proteins existed in vivo between the posterior frontal and sagittal sutures. However, the production of the critical, regulatory cytokine transforming growth factor beta-1 was equal between the two suture complexes, lending further support to the hypothesis that dura mater regulates the fate of the overlying cranial suture.

Animals↗
PubMed1984

Evaluation of suture techniques for mitral valve replacement.

Although periprosthetic leak is presently uncommon after mitral valve replacement, suture line disruption still occurs and may be significant in some patients. Suture technique is obviously an important factor in preventing disruption, but few authors have examined this variable. The purpose of this study was to determine which of four suture methods for mitral valve replacement maximized prosthetic stability in the mitral anulus. Horizontal mattress sutures with subannular pledgets, horizontal mattress sutures with supra-annular pledgets, figure-of-eight sutures, and interrupted simple sutures were compared. A Carpentier-Edwards sewing ring was sutured to the mitral anulus of intact canine left ventricles, each technique randomly assigned to eight hearts. Suture size, number of bites, and annular depth were maintained constant in all groups. Progressively increasing force was applied across the suture line until disruption occurred. The yield force at initial suture disruption was measured by a semiconductor strain-gauge transducer and defined the experimental end point. Subannular pledget-supported sutures required the greatest force (38.4 +/- 0.8 N) to produce prosthetic dehiscence and were significantly more secure than supra-annular pledgets (32.7 +/- 0.5 N). The two suture techniques in which pledgets were used were better than the nonsupported sutures, the mean yield force averaging 28.3 +/- 0.3 N for figure-of-eight and 21.3 +/- 0.7 N for interrupted simple sutures. Although clinical techniques may vary with prosthetic valve design, surgical preference, or pathological anatomy, this study suggests that horizontal mattress sutures with subannular pledgets provide the best prosthetic valve stability during mitral valve replacement.

Animals↗
PubMed2003

Suture growth modulated by the oscillatory component of micromechanical strain.

Sutures are fibrous connective tissue articulations between intramembranous craniofacial bones. Sutures are composed of fibroblastic cells with their matrices in the center and osteogenic cells in the periphery producing a matrix that is mineralized during skeletal growth. Whether oscillatory forces stimulate sutural growth is unknown. In the present work, we applied static and cyclic forces with the same peak magnitude of 5N to the maxilla in growing rabbits and quantified (1) acute in vivo sutural bone strain responses and (2) chronic growth responses in the premaxillomaxillary suture (PMS) and nasofrontal suture (NFS). Bone strain recordings showed that the waveforms of static force and 1-Hz cyclic force were expressed as corresponding static and cyclic sutural strain patterns in both the PMS and NFS, with the mean peak PMS strain (-1451 +/- 137 microepsilon for the cyclic and -1572 +/- 138 microepsilon for the static) approximately 10-fold higher than the mean peak NFS strain (124 +/- 9 microepsilon for the cyclic and 134 +/- 9 microepsilon for the static). Strain polarity was the opposite: compressive for the PMS but tensile for the NFS. However, on application of repetitive 5N cyclic and static forces in vivo for 10 minutes/day over 12 days, cyclic loading induced significantly greater sutural widths for the compressed PMS (95.1 +/- 8.3 microm) than sham control (69.8 +/- 8.2 microm) and static loading (58.9 +/- 2.8 microm; p < 0.01). Interestingly, the same trend was true for the NFS under tensile strain: significantly greater sutural width for cyclic loading (267.4 +/- 64.2 microm) than sham control (196.0 +/- 10.1 microm) and static loading (169.9 +/- 11.4 microm). Cell counting in 110 x 110 microm grids laid over sutures disclosed significantly more sutural cells on repetitive cyclic loading than sham control and static loading (p < 0.05) for both the PMS and NFS. Fluorescent labeling of newly formed sutural bone demonstrated more osteogenesis on cyclic loading in comparison with sham control and static loading. Thus, the oscillatory component of cyclic force or more precisely the resulting cyclic strain experienced in sutures is a potent stimulus for sutural growth. The increased sutural growth by cyclic mechanical strain in the tensed NFS and compressed PMS suggests that both microscale tension and compression induce anabolic sutural growth response.

Animals↗
PubMed2002

Mechanical behavior of chemically treated ostrich pericardium subjected to uniaxial tensile testing: influence of the suture.

The mechanical behavior of sutured ostrich pericardium was studied by uniaxial tensile testing. One hundred forty-four tissue specimens were assessed: 96 sutured samples (48 in which a centrally located suture was placed at an angle of 90 degrees with respect to the longitudinal axis, whereas in the remaining 48, a centrally located suture was placed at a 45 degrees angle to the longitudinal axis, in sets of 12 samples each, sewn with sutures made of Gore-Tex, nylon, Prolene, or silk), and 48 unsutured controls. Each group of 24 samples sewn at one angle or the other with the different suture materials was assayed together with a corresponding control group of 12 unsutured samples. The mean tensile strengths in the unsutured controls ranged between 30.16 MPa and 43.42 MPa, whereas those of the sutured sets ranged from 14.68 MPa to 21.91 MPa. The latter presented a statistically significant loss of resistance (p < 0.01) when compared with the unsutured tissue samples. The angle of the suture with respect to the longitudinal axis influenced the degree of shear stress produced by the suture, as well as the behavior of the different suture materials used. The set of samples sewn with Prolene appeared to be that most sensitive to changes in the angle of the suture, whereas tissue sewn at a 45 degrees angle with Gore-Tex presented lower shear stress values in comparison with samples in which the other three materials were used. A method of tissue selection based on morphological and mechanical criteria was used to ensure the homogeneity of the results in such a way that the coefficients of determination (R2) for the stress/strain curve fitting equation ranged between 0.888 and 0.995. This excellent fit made it possible, applying regression analysis, to predict the mechanical behavior of a specimen by determining that of a contiguous tissue sample. Thus, it should be possible, at least theoretically, to characterize the behavior of a specific region or zone of the biomaterial. In conclusion, ostrich pericardium exhibits strong resistance to rupture, even when sutured. The selection method used ensures the homogeneity of the samples and, thus, of the results. The angle of the suture with respect to the longitudinal axis, where the load is centered, determines the shear stress produced by the suture and the mechanical behavior of each suture material.

Animals↗
PubMed2005

A biomechanical analysis of suture materials and their influence on a four-strand flexor tendon repair.

PURPOSE: Flexor tendon repair strength depends on the suture technique and the suture material used. Configurations that incorporate locking loops prevent sutures from pulling through the tendon but typically fail because of suture breakage. The choice of suture material therefore influences repair strength. This study investigated the mechanical properties of 5 nonabsorbable 4-0 suture materials (monofilament nylon, monofilament polypropylene, braided polyester, braided stainless steel wire, and braided polyethylene) and evaluated their performance when used in a locking 4-strand flexor tendon repair configuration. METHODS: Five samples of 2 strands of each suture type were tested mechanically to determine the material stiffness and ultimate load. In addition, 50 fresh porcine flexor tendons were divided and repaired with each of the 5 suture materials using a 4-strand single-cross technique. Gap force, ultimate strength, and stiffness were measured to compare biomechanical performance. RESULTS: All repairs failed by suture rupture at the locking loop. Fibrewire and stainless-steel sutures and repairs were significantly stronger and stiffer than the other suture types. The results for Prolene and Ethibond were similar in the tendon repair groups with respect to gap and ultimate forces although Ethibond provided significantly increased repair stiffness. Nylon sutures and repairs consistently produced the poorest mechanical performance in all outcome measures. CONCLUSIONS: Suture material strongly influences the biomechanical performance of multistrand tendon repairs and is an important consideration for the surgeon. Fibrewire and stainless steel are the most biomechanically suitable suture materials for flexor tendon repair whereas nylon is the least suitable. Further developments in suture materials are important for advancements in flexor tendon repair strength.

Animals↗
PubMed2002

Spontaneous wound dehiscence after removal of single continuous penetrating keratoplasty suture.

PURPOSE: To determine the incidence and complications of spontaneous wound dehiscence after removal of a single continuous penetrating keratoplasty (PK) suture. DESIGN: Retrospective consecutive, noncomparative interventional case series. METHODS: Retrospective review of 324 consecutive continuous suture PKs performed between 1992 and 1999. RESULTS: Sixty-nine (21.3%) of 324 PKs reviewed had the continuous suture removed. The average interval for suture removal after PK was 24.5 +/- 15 months (range, 2.8-63.3 months). Five of the 69 eyes (7.2%) developed spontaneous wound dehiscence without direct eye trauma. In the five eyes that developed wound dehiscence, the continuous suture was removed at 24.6 +/- 10.3 months (range, 14-42 months). Dehiscence occurred at 11.6 +/- 6.5 (range, 3-18) days after suture removal. Significant history associated with wound dehiscence included coughing, yawning, falling without trauma to the eye, and spontaneous wound separation. The reasons for suture removal were astigmatism in four of five (80%) patients and a broken suture in one of the five patients. In four of five (80%) patients, the location of wound dehiscence correlated with the steep axis of corneal keratometry before suture removal. Surgical intervention preserved the presuture removal best-corrected visual acuity in four of the five eyes. No eyes with an intact suture spontaneously dehisced. CONCLUSIONS: The rate of spontaneous wound dehiscence after removal of a continuous suture in our series was 7.2%. All spontaneous dehiscences occurred within 2 weeks after suture removal. Older patients, who had PK for corneal edema with postoperative astigmatism and have been using corticosteroids drops for prolonged periods of time, are at higher risk of wound dehiscence. Patients should be monitored closely during the first 2 weeks after removal of a continuous suture for signs of wound separation, especially when suture removal is performed for astigmatism. Patients should be cautioned about the risk and symptoms of wound dehiscence before suture removal to facilitate early recognition and intervention for preservation of best visual potential.

Aged↗
PubMed2002

Flexor tendon repair using shape memory alloy suture: a biomechanical evaluation.

The purpose of the current study was to test in vitro a new shape memory alloy suture for flexor tendon repair. Forty fresh-frozen human anatomic flexor superficialis and profundus tendons were divided and repaired via the cruciate four-strand technique using one of two suture materials (the shape memory alloy suture and the 4-0 Ethibond suture). The forces required to cause a 1, 2, and 3 mm gap, ultimate load to failure, and repair stiffness were compared. Twenty specimens of each suture material also were tensile tested for load to failure, tensile strength, and elongation at failure. The shape memory alloy suture had a significantly higher mean resistance force to 1, 2, and 3 mm gap formation than the 4-0 Ethibond suture (47 N versus 31 N, 51 N versus 36 N, and 57 N versus 41 N, respectively). The shape memory alloy suture repair was 40% stronger than the 4-0 Ethibond suture (61.9 +/- 8.8 N versus 44.3 +/- 10.6 N). Repair with the shape memory alloy suture was significantly stiffer than repair with the 4-0 Ethibond suture (8.1 +/- 1.0 N/mm versus 6.1 +/- 0.9 N/mm). The load to failure and tensile strength of the shape memory alloy suture were significantly higher than that of the 4-0 Ethibond suture. The values of elongation for the two materials were not significantly different. The results of the current study suggest that the shape memory alloy suture may be superior to the 4-0 Ethibond suture in resisting gap formation in the range of forces generated in the early rehabilitation protocol and may be the future material of choice for tendon repairs.

Alloys↗
PubMed2004

Strength and knot security of braided polyester and caprolactone/glycolide suture.

BACKGROUND: Appropriate suture selection is necessary in providing mechanical stability to soft tissue reconstructions. Caprolactone/glycolide (Panacryltrade mark) became a popular suture, possessing excellent handling properties; however, clinical observations questioned the knot security of caprolactone/glycolide. Caprolactone/glycolide is still available on many commercial suture anchor systems. This study compared the security of the knots and ultimate tensile strength of braided caprolactone/glycolide suture to that of a commonly used suture material, braided polyester (Ethibondtrade mark). MATERIALS: Suture knots of No. 2 braided polyester suture and No. 2 braided caprolactone/glycolide suture were submersed in a physiologic saline solution and stressed using a continuous (non-cyclic) load, simulating a single maximal loading event in a clinical setting. Continuous loading was done to achieve clinical suture knot failure (3-mm knot slippage), then continued until catastrophic suture failure (suture breakage) occurred. Ten trials of each suture were tested. RESULTS: Force required to cause knot slippage of 3 mm was greater for braided polyester than for braided caprolactone/glycolide (p <. 0001, unpaired Students' t-test). Forces resulting in catastrophic failure were greater for braided polyester than braided caprolactone/glycolide (p = .0284, unpaired Students' t-test). CONCLUSIONS: These data have important implications in the selection of suture materials for repair of soft tissue injuries. In the clinical setting, a single maximal loading event may result in suture failure. These data indicate that braided polyester possesses superior in-vitro mechanical properties and suggest that braided polyester may provide greater security in-vivo than braided caprolactone/glycolide suture.

Dioxanes↗
PubMed1997

A comparison of two selective interrupted suture removal techniques for control of post keratoplasty astigmatism.

PURPOSE: Two selective interrupted suture removal techniques were compared to determine which technique resulted in earliest, best visual acuity and least postoperative astigmatism. METHODS: Sixty-five consecutive optical penetrating keratoplasties were performed using 12 interrupted 10-0 nylon sutures and a 12-bite continuous 10-0 nylon suture, and were alternately assigned to 1 of 2 selective suture removal groups. All patients had refraction, keratometry, and videokeratoscopy postoperatively, starting at 6 weeks. Six weeks postoperatively, Group I underwent simultaneous removal of six alternate sutures, with the first of the 6 sutures removed at the steepest meridian, while Group II had selective sutures removed only at the steepest meridian, if associated with greater than 2 diopters of astigmatism in that meridian. Subsequently, interrupted sutures were then selectively removed until the resultant astigmatism approached 3.0 diopters or less. Measurements of resultant astigmatism are reported prior to selective suture removal, following selective suture removal, at 6 months postoperatively, at the completion of all selective suture removal, and at the final visit. RESULTS: At 6 months, residual astigmatism after the 2 techniques of selective suture removal, as measured by refraction, keratometry, and computer-assisted videokeratoscopy, was 2.8, 3.0 and 3.4 diopters for Group I, and 2.2, 2.6 and 3.7 diopters for Group II. At 1 year, the average final visit, astigmatism was 2.5, 2.4 and 2.7 diopters for Group I, and 2.1, 2.0 and 2.3 diopters for Group II. By the final visit, a best corrected vision of 20/50 or better was achieved in 86% of eyes in Group I and in 65% of eyes in Group II, and there was a significant difference in average keratometry of 47.4 diopters in Group I compared to 46.0 diopters in Group II and, as measured by videokeratoscopy, 47.9 diopters in Group I compared to 45.8 diopters in Group II. CONCLUSIONS: Selective suture removal by either technique reduces keratoplasty astigmatism with residual interrupted and continuous sutures in place. The combined use of refraction, keratometry, and videokeratoscopy probably provides more reliable and reproducible quantitative measurements of astigmatism. Minimizing astigmatism by selective suture removal is a major factor in the attempt to achieve excellent and visual function in the majority of patients who have undergone penetrating keratoplasty.

Adult↗
PubMed1990

Some biomechanical considerations of polytetrafluoroethylene sutures.

The biomechanical performance of polytetrafluoroethylene (PTFE) sutures has been compared with that of polypropylene sutures, the standard to which other sutures used in vascular and cardiac surgery are compared. The PTFE is supple and has no plastic memory, while the polypropylene suture is stiff and retains its plastic memory. In addition, the rate of creep encountered in the PTFE suture was significantly less than that of the polypropylene suture. The knotting profiles for knot security for either a square, granny, or surgeon's knot for polypropylene sutures were three throws each. In contrast, knot security with either a square or granny PTFE knot was accomplished with seven throws; six throws were needed for a secure surgeon's knot. The breaking strength of the unknotted and knotted PTFE sutures was approximately one half as great as that for the unknotted and knotted polypropylene sutures. Knot construction significantly reduced the breaking strength of polypropylene sutures but did not alter the breaking strength of PTFE sutures. The percent elongation experienced by both sutures before breakage did not differ significantly. The elasticity, as measured by work recovery, for the polypropylene suture was greater than that for the PTFE suture. On the basis of its unique biomechanical performance characteristics, the PTFE suture should have an important place in vascular and cardiac surgery.

Physical Phenomena↗
PubMed1996

Increased bone formation and osteoblastic cell phenotype in premature cranial suture ossification (craniosynostosis).

Craniosynostosis is a heterogeneous disorder characterized by premature fusion of the skull bone sutures. To evaluate the pathogenesis of premature cranial suture ossification in craniosynostosis, we have evaluated the histologic indices of bone formation and the characteristics of osteoblastic cells derived from normal and affected cranial sutures in 47 infants and children, aged 3-18 months, with nonsyndromic craniosynostosis. The histomorphometric analysis of normal and fused sutures showed an age-related decline in the extent of endosteal bone surface covered with osteoid and osteoblasts during postnatal suture ossification. Bone formation was 20-50% higher at 3-6 months of age in fused sutures compared with normal sutures in the same patients. Cells derived from normal and fused sutures displayed characteristics of the osteoblast phenotype in culture. Analysis of [3H]thymidine incorporation into DNA from 1-14 days of culture showed an age-related decrease in osteoblastic cell growth in both normal and affected sutures. The proliferation of osteoblastic cells isolated from fused sutures was similar at all ages to that of cells isolated from normal sutures in the same patients. In contrast, alkaline phosphatase activity and osteocalcin production by osteoblastic cells cultured in basal conditions and after stimulation with 1,25-dihydroxyvitamin D (1,25[OH]2D3), were 53-74% higher in fused sutures compared with cells isolated from normal sutures in the same patients. The results indicate that bone formation activity at the suture site is locally increased in craniosynostosis, and this disorder is associated with increased in vitro parameters of osteoblastic cell differentiation, suggesting that an increased maturation of osteoblastic cells at the site of the suture leads to the premature ossification in nonsyndromic craniosynostosis.

Aging↗
PubMed1995

New laparoscopic suturing device: initial clinical experience.

OBJECTIVES: New instrumentation and techniques have enabled laparoscopic surgeons to perform complicated reconstructive procedures. Few centers have attempted these procedures because of the excessive time involved with laparoscopic suturing. The Endo stitch suture device was developed to facilitate suture placement. We clinically compared conventional intracorporeal suturing and Endo Stitch suturing for laparoscopic suture placement and knot tying. METHODS: Intracorporeal suturing was used to complete laparoscopic dismembered pyeloplasties and bladder neck suspensions. Sutures were placed with either needle holders and graspers or the automatic suture device. A total of 85 maneuvers were assessed. Operative videotapes were reviewed to assess accuracy of suture placement, knot tying, and time to place suture and tie knots. All suturing was performed by an experienced laparoscopist. RESULTS: Accuracy of stitch placement and knot tying were equivalent. The average time for stitch placement with the Endo Stitch was 43 +/- 27 seconds (n = 41). This was significantly less than the average stitch placement time for conventional suturing, which was 151 +/- 24 seconds (n = 14). The Endo Stitch knot tying was completed in an average of 74 +/- 50 seconds (n = 17), whereas knot tying with the conventional technique took 197 +/- 70 seconds (n = 13). The needle is automatically loaded in the Endo Stitch after each suture and is immediately ready. CONCLUSIONS: The Endo Stitch device reduced the amount of time needed for placement of stitches and knot tying. Reconstructive laparoscopic procedures requiring multiple suture placement may be completed in a shorter time period using this instrument.

Equipment Design↗
PubMed1997

Microbial findings in suture erosion after penetrating keratoplasty.

PURPOSE: The purpose of the study was to evaluate the presence of microorganisms in eroded (broken or loose) sutures post-penetrating keratoplasty (PKP). METHODS: Fifty-five consecutive episodes of eroded 10-0 nylon sutures post-PKP in 35 eyes were evaluated. Eroded sutures were removed and, along with a swab from the conjunctiva, studied for aerobic and anaerobic bacteria. Preoperative diagnosis, elapsed time since surgery, presence of symptoms, suture location, infiltration, vascularization, and mucous at the suture site were recorded. Student's t test was used for statistical analysis. RESULTS: The average time from PKP to suture removal was 31.6 months. Eyes treated with topical steroids presented earlier suture erosions (P = 0.05). Of the 55 sutures, 34 were sterile, and in 21, both Staphylococcus epidermidis and diphtheroids (mixed flora) were cultured. Of the 55 conjunctivas, 32 were sterile, 22 showed mixed flora, and 1 had Pseudomonas. Sutures eroded for more than 24 hours had more positive cultures than those eroded for 24 hours or less (P = 0.043). Sutures located superiorly had fewer positive cultures than did those in the palpebral fissure area (P = 0.044). Eyes with repeated suture erosions had more culture-positive sutures (P = 0.017) and conjuctivas (P = 0.014) at the first erosion in comparison with the second erosion. Infiltration, vascularization, or muscus at the suture site did not correlate with positive cultures. CONCLUSIONS: Bacteria are encountered at the site of eroded sutures. Patients with PKP should report symptoms immediately, and eroded sutures should be removed as early as possible.

Adolescent↗
PubMed2003

Biomechanics of craniofacial sutures: orthopedic implications.

Sutures are soft connective tissue articulations between craniofacial bones. Suture mechanics deals with patterns of mechanical stress experienced in sutures resulting from natural activities such as mastication and exogenous forces such as orthopedic loading. Patterns of sutural mechanical stress can be delineated readily as sutural strain using strain gages attached over the suture. In mastication, complex sutural strain patterns have been elucidated in a few species. Mechanical stresses are not transmitted in the skull as a continuing gradient, for different sutures are capable of redefining a propagating mechanical force as predominately tensile or compressive strain. Exogenous mechanical forces with engineering waveforms such as static and sine wave at different frequencies induce corresponding waveforms and rates of sutural strain, providing the basis for applying novel mechanical stimuli to engineer sutural growth. The available data on suture mechanics converge to a hypothetical theme that mechanical forces regulate sutural growth by inducing sutural mechanical strain. Various orthopedic therapies, including headgear, facemask, and functional appliances may induce sutural strain, leading to modification of otherwise natural suture growth.

Biomechanical Phenomena↗
PubMed1999

Coronal suture response to distraction osteogenesis in rabbits with delayed-onset craniosynostosis.

Recent studies have identified a subpopulation of persons with craniosynostosis who exhibit progressive or delayed-onset synostosis and mild cranial vault deformities. These persons may be good candidates for nonextirpation distraction osteogenesis. The present studies were designed to determine force-displacement parameters and assess the effects of distraction osteogenesis on coronal suture growth and morphologic characteristics in a rabbit model with congenital, delayed-onset craniosynostosis. Data were collected from a total of 178 rabbits: 71 normal controls; 16 normal controls with distraction; 72 with delayed-onset coronal suture synostosis; and 19 with delayed-onset coronal suture synostosis and distraction. At 10 days of age, all rabbits had amalgam markers placed on both sides of the coronal suture. In the force-displacement study, force-displacement distractors were placed across the coronal suture and distracted acutely for 1.0 mm at 42 days of age. Force-displacement curves for the coronal suture were best described by a third-order polynomial regression equation for both normal and synostosed groups. Significant differences (P < 0.05) were found in the mean force necessary to distract a normal suture 1 mm in distance (13.72 kg) compared with a suture with delayed-onset synostosis (48.39 kg). A significant (P < 0.05) relationship was also found between the extent of synostosis and the distractive force in rabbits with delayed-onset synostosis. In the distraction study, internal distractors were fixed across the coronal suture at 25 days of age and percutaneously and intermittently activated at an average of 0.11 mm/day for 42 days (4.54 mm total). Serial radiographs were taken at 10, 25, 42, and 84 days of age. Results revealed that rabbits with delayed-onset synostosis and distraction had significantly (P < 0.01) more coronal suture growth rates compared with rabbits with delayed-onset synostosis and no distraction. Coronal sutures were harvested at 84 days of age for qualitative histologic examination. Normal, distracted coronal sutures showed widened sutural ligaments and thin, active osteogenic fronts. In contrast, distracted coronal sutures from rabbits with delayed-onset synostosis showed narrowed sutural ligaments, thickened and blunt osteogenic fronts, and increased collagen and bony matrix deposition compared with controls. Results suggest that distraction osteogenesis without corticotomy may be a treatment alternative in persons with progressive, delayed-onset synostosis. However, these preliminary data also suggest that distractive forces may accelerate or stimulate osteogenesis differentially in persons with craniosynostosis, possibly through an underlying genetic disorder of bone and cytokine regulation. These differential osteogenic responses to distraction, if validated clinically, will need to be taken into account when planning distraction rate and rhythm protocols for patients with craniosynostosis.

Age of Onset↗