Silk Suture

A 2-0 silk suture placed through the dorsal tongue facilitates manipulation of the tongue during the procedure.

From: Sleep Apnea and Snoring , 2009

COMPLICATIONS OF RENOVASCULAR SURGERY

David Canes MD , John A. Libertino MD , in Complications of Urologic Surgery (Fourth Edition), 2010

Synthetic Grafts: Thrombosis, Delayed Bleeding, and Fistula Formation

Dacron grafts and silk sutures have been abandoned because of delayed complications of late bleeding from arterial-enteric fistulas and a high rate of thrombosis. 35 Only if autogenous graft is not available should polytetrafluoroethylene (PTFE) be used exclusively. Although concerns prevail about graft occlusion, infection, and enteric fistulas with synthetic grafts, one series suggested that these concerns may be unfounded. 36 Early and late occlusion occurred in 1.4% and 4.8%, respectively. We still maintain that synthetic material be used only when autogenous graft is not available.

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Graham Patch Repair

Babak Sarani MD , Andrea Badillo MD , in Surgical Pitfalls, 2009

• Prevention

Three to four interrupted 3-0 silk sutures are placed across the perforation. The sutures are inserted approximately 1 cm away from the edge of the perforation to accommodate the tendency of the suture to pull through the friable, inflamed duodenum. Ideally, all sutures should be placed through normal intestine, away from the area of inflammation. The needle should be retrieved and reintroduced from within the perforation during suture placement so as to place the suture using two passes of the needle ( Figs. 15-1 and 15-2). This minimizes torque or undue force on the duodenum itself and helps prevent inadvertent worsening of the perforation.

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Investigating Fracture Mechanisms of Some Non-Absorbable Sutures in vivo

A.S. Hockenberger , E. Karaca , in Medical and Healthcare Textiles, 2010

RESULTS AND DISCUSSION

Fig. 1a shows the surface of untreated silk suture, already containing many impurities. The filaments have no regular diameter and surface characteristics. It is also difficult to distinguish the single filaments. They seem to stick to each other and stay as bundles.

Silk is derived from the cocoon of the silkworm (Bombyx mori). It is defined as protein fibre. Fibroin chains are believed to be nearly full-extended, highly crystalline, and almost perfectly aligned in the fibre direction, all of which contribute to the fibre's considerable stiffness and strength. Fibrous proteins, such as silk, are characterised by a highly repetitive primary sequence that leads to significant homogeneity in fine structure. Because of these structural properties it shows impressive mechanical properties and provides important material options in the field of controlled release, biomaterials and scaffolds for tissue engineering (5).

At the broken ends of silk suture the flattening of the filaments was observed before implantation. This contributes to the presence of lateral forces on loading (see Fig. 4).

Figure 4. The silk filaments sticking together at the broken ends after tensile strength test before implantation

According to US Pharmacopoeia an absorbable biomaterial (suture) is defined as one that loses most of its tensile strength within 60   days post-implantation in vivo. Within this definition, silk is correctly classified as non-absorbable. However, according to literature, silk is degradable but over longer time periods due to proteolytic degradation usually mediated by a foreign body response. In general, silk fibres lose the majority of their tensile strength within one year I, and fail to be recognised within two years (2).

When implanted in living tissues, suture materials inevitably elicit a wide range of tissue reactions and cellular responses. The degree of tissue reaction depends largely on the chemical nature and physical configuration of the various suture materials. Suture materials of a biological nature produce more marked tissue reactions than those of a synthetic nature, while a greater response is caused by multifilament sutures than by monofilament sutures (3). Therefore braided and protein based silk sutures of the study showed more pronounced fibrous tissue capsules in vivo (see Fig. 5a). In the knotted form, the break was always beneath the knot whilst the knot remained in place. Also, after 3 and 8   weeks in vivo, a more clear fibrous capsule was seen around the knot due to a greater quantity of suture material (see Fig. 5b). This tissue capsule form plays an important role on the fracture mechanism of silk suture post implantation. The filaments were held or glued together by this capsule. When broken ends were analysed the filaments were sticking together and no scattering of broken filaments were seen, (see Fig. 6).

Figure 5. The fibrous tissue capsule of the silk sutures after implantation [(a)straight form (0 USP) (X10); (b)knotted form (3/0 USP)]

Figure 6. The broken ends of the silk sutures (0 USP) after tensile strength test post implantation (X10)

Aliphatic polyamides are polymerised either from polycondensation of a dicarboxylic acid and a diamine, or through a ring-opening polymerisation of appropriate lactams. In this study monofilament polyamide with repeating unit (-NH(CH2 )5CO-) was used. Polyamide 6 is made from caprolactam. Among the synthetic non-absorbable sutures, polyamides are probably the one most susceptible to degradation. However, due to its amide linkages on the molecular chains and hydrogen bonding between the chains, it has high tensile strength and its flexible chain structure gives excellent elastic properties. The main disadvantage of using polyamide is its prominent memory, which consequently decreases its knot security. In this study undone knots after knot strength measurements, before and after implantation, were also observed (see Fig. 7).

Figure 7. The opened knot of polyamide suture (3/0 USP) after knot strenght test

Although polyamide is considered a non-absorbable suture, it still undergoes partial degradation through hydrolysis at a very slow rate due to –NHCO- groups on the polymer backbone as they are very polar and can hydrogen bond with water easily.

Polyamide monofilament sutures show smooth surfaces with a circular cross-section before implantation (see Fig. 1b). No fibrous tissue capsule was observed on the suture surface or around the knot post implantation. This is contributed to its smooth surface characteristic. However a closer examination of the opened knot shows flattening of the knot region (see Fig. 7). This is attributed to the ductile structure of polyamide sutures. It shows permanent deformation due to lateral forces exerted during loading. The rupture of the melt-spun synthetic fibres like polyamide is dominated by yield. Plastic yield of material causes the crack to open into a V-notch, which propagates steadily into the specimen. This typical ductile fracture was seen at the broken ends, after tensile tests, both before and after implantation (see Fig. 8).

Figure 8. The ductile fracture mechanism of the polyamide suture (3/0 USP) after tensile strength test

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Vitreous, Retinal, and Choroidal Biopsy

Diana V. Do , Quan Dong Nguyen , in Retina (Fifth Edition), 2013

Transscleral biopsy

The conjunctiva is incised, and the rectus muscles in the involved quadrant are isolated with silk sutures. 59 In biopsies of the choroid and retinal pigment epithelium, the retina tends to bulge into the biopsy site with a risk of retinal tear or incarceration. This risk is reduced by performing a pars plana vitrectomy first. 55 If visualization is adequate, a heavy barrier of photocoagulation, cryotherapy, or diathermy is applied some days preoperatively around the planned biopsy area. Otherwise, endolaser therapy or cryotherapy is applied at the time of vitrectomy. The biopsy site is marked on the sclera, and a 6 × 6 mm scleral flap, nearly full-thickness and hinged (usually posteriorly), is dissected beginning about 5–6 mm posterior to the limbus, depending on the lesion site. The flap is retracted, exposing a near-bare choroid with a few remaining thin fibers of overlying sclera. Diathermy or cautery is done along the outer margin of the inner choroidal bed. A sharp blade is used to make an incision, or two parallel incisions, through the choroid (and retina, if retina is to be removed). One blade of a 0.12 forceps is placed through the incision, and the biopsy specimen is grasped at one edge. The block excision is then completed with Vannas scissors (Fig. 124.20). During removal of the specimen, particular attention is directed at grasping the tissue only once and ensuring that the entire specimen is delivered in one piece. If the retina is not being removed, it is carefully separated from the choroid and left intact. The biopsy specimen is then placed in fixative or handled as planned with the pathologist. Any prolapsed vitreous is then removed from the wound, and the scleral flap is sutured with interrupted 9–0 nylon or 7–0 Vicryl. Fluid–gas exchange is performed.

Another technique for obtaining a specimen of sclera, choroid, retinal pigment epithelium, and retina from the eye is to use a corneal trephine and to reconstitute the eye wall with a full-thickness donor scleral graft. In this situation, hemostasis may be improved by systemic hypotensive anesthesia. 49,50,60

Cyanoacrylate tissue glue can be used to stabilize the choroidal specimen before its removal from the eye. 49,50 A drop of cyanoacrylate glue is applied to the exposed choroid, forming a dense plaque that can be grasped or glued to an arrowhead sponge.

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The Forehead Flap: Technique – Getting the Operation Underway, Surgical Planning and the Use of Templates – Step-by-Step Details of Transfer, the Intermediate Operation, and Revision

Frederick J Menick MD , in Nasal Reconstruction, 2009

Patient safety

Immediately after induction of general anesthesia, the endotracheal tube is secured with a 2-0 silk suture, sutured to the upper or lower lip frenulum or tied to a tooth ( Figure 7-7).

The central face and chin must be visible and available for tissue manipulation. It should not be obstructed or distorted by tape used to secure the endotracheal tube.

Bland ophthalmic ointment is applied to the globe. The upper and lower eyelids are sutured together with 6-0 suture to protect the cornea (Figure 7-8). Inadvertent corneal abrasion must be avoided. Or the eyes are covered with occlusive transparent plastic wound dressing.

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OPERATIVE MANAGEMENT OF PULMONARY INJURIES: LUNG-SPARING AND FORMAL RESECTIONS

Juan A. Asensio , ... Louis R. Pizano , in Current Therapy of Trauma and Surgical Critical Care, 2008

Right middle lobectomy

For a right middle lobectomy, the pulmonary artery branch to the middle lobe is identified, ligated with 0 silk sutures, transfixed with 2-0 silk sutures, and divided. The middle lobe division of the superior pulmonary vein is similarly ligated with 0 silk sutures, transfixed with 2-0 silk sutures, and divided. With these two vessels addressed, the trauma surgeon carefully isolates the middle lobe bronchus, which is then transected with a TA-30 or TA-45 stapler with 4.8-mm staples. 94, 95

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BLADDER AND CLOACAL EXSTROPHY

Michael Mitchell MD , Richard Grady MD , in Ashcraft's Pediatric Surgery (Fifth Edition), 2010

Preoperative Care

After delivery, to reduce trauma to the bladder plate, the umbilical cord should be ligated with silk suture rather than a plastic or metal clamp. A hydrated gel dressing may be used to protect the exposed bladder from superficial trauma. This type of dressing is easy to use, keeps the bladder plate from becoming desiccated, and stays in place to allow handling of the infant with minimal risk of trauma to the bladder. A plastic wrap is an acceptable alternative. Dressings should be replaced daily and the bladder should be irrigated with normal saline with each diaper change. A humidified air incubator may also minimize bladder injury. 62

We routinely use intravenous antibiotics in the preoperative and postoperative period to decrease the risk for infection after reconstruction. We also perform preoperative ultrasonography to assess the kidneys and establish a baseline examination for later ultrasound studies. Preoperative spinal ultrasound examination should be considered if sacral dimpling or other signs of spina bifida occulta are noted on physical examination.

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Surgical Management

Andrew M Thompson , ... Anthony CB Molteno , in Glaucoma (Second Edition), 2015

STEP 9 Covering The Tube.

Reposition the lamellar scleral flap over the tube, and suture loosely in position using interrupted 7/0 silk sutures, one each side of the flap. The tension of these sutures can be used to adjust the angle of the tube, if necessary. In many cases, the flap can be left unsutured and held in position by Tenon's fascia that is sutured to sclera at the limbus.

If a Vicryl tie is used, ensure that the tie lies in contact with vascular Tenon's fascia. If the lamellar scleral flap covers the tie and separates it from Tenon's fascia there is considerable delay before the Vicryl breaks down. If the flap covers the tie it is not necessary to shift the plate. Instead, cut a small V-shaped area out of the posterior edge of the flap in order to expose the tie to Tenon's fascia.

If the sclera is unduly thin or scarred so that the lamellar scleral flap does not adequately cover the tube, a patch of donor sclera or equivalent tissue should be used to supplement or replace it. If using glycerin-preserved donor sclera, place the patch either beneath or above the lamellar scleral flap. Position the donor scleral patch to leave 1 mm between its anterior edge and the cornea, and ensure the posterior edge does not contact the anterior edge of the episcleral plate. Suture the patch in position 1–2 mm from its anterior edge using two interrupted 7/0 silk sutures. If donor sclera overlaps the cornea, a layer of corneal epithelium may grow between the host tissue and donor sclera and prevent the latter from being incorporated into the tissues.

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Current Status on Synthetic Grafts

Brian R. Waterman MD , ... Gordon Mackay MD, FRCS, FFSEM , in The Anterior Cruciate Ligament (Second Edition), 2018

History of Synthetic Grafts for Anterior Cruciate Ligament Reconstruction

Although unsuccessful, Alwyn-Smith first attempted synthetic anterior cruciate ligament (ACL) reconstruction in 1918 with silk sutures. Synthetic grafts were not commercially introduced until the 1970s, and their use in ACL augmentation and/or reconstruction had a significant surge in popularity in the late 20th century. At the time, routine surgery entailed open patellar tendon autograft ACL reconstruction and 6 weeks of strict postoperative immobilization. A sterile, off-the-shelf synthetic ligament offers immediate availability while obviating donor site morbidity due to autograft harvest and the requirement for significant range of motion restrictions. Similarly, synthetic grafts reduce the risk of disease transmission associated with allograft use. However, early clinical data revealed relatively higher rate of failure with first-generation synthetic grafts compared with autogenous tissue, as well as an increased risk of late infection, considerable bone tunnel enlargement, and pronounced sterile effusions or diffuse synovitis. In response, West and Harner 1 stated that there was no current indication for synthetic ligaments in cruciate ligament reconstruction.

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Eyelid Burn Reconstruction

Branko Bojovic , Matthias B Donelan , in Global Reconstructive Surgery, 2019

Post-Operative Care

Dressings

Typical bolster dressings using non-adherence gauze wrapped around a cotton padded bolster and secured to the wound with silk sutures are our preference. The use of temporary tarsorrhaphy is also an excellent technique to provide additional support during the healing and maturation phases.

Splinting

We firmly believe in splinting in the form of malleable conformers that fit the delicate periorbital area comfortably. In the later phases of reconstruction, facial compressive mask therapy has advantages in providing upper and lower eyelid support and pressure, if correctly designed and manufactured.

Therapy

A close collaboration with our occupational and physical therapy colleagues is mandatory in almost all cases we treat. Their value and expertise cannot be underemphasized or overstated as part of achieving excellent short- and long-term outcomes. 6

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