Deep Tissue Absorbable Suture Technique: Inverted Simple Interrupted Tutorial

Sutures are classified as absorbable (natural like catgut, synthetic like polyglactin/Vicryl) or non-absorbable (natural like silk, synthetic like polypropylene/Prolene). Color coding: brown for catgut, blue for polypropylene, black for silk. Vicryl is synthetic absorbable monofilament. Chromic catgut is natural absorbable from sheep gut. Subcuticular sutures use Monocryl (3-0) for cosmetic closure. Suture selection depends on tissue type, location, and cosmetic requirements. Mnemonics: PMV for absorbable synthetic, PEN for non-absorbable. Absorption timelines vary: Vicryl absorbs in 180 days.

Surgical sutures are classified into two main categories based on absorption: non-absorbable sutures (silk, polyester, nylon, stainless steel, prolene, PVDF) which require removal after healing, and absorbable sutures (vicryl, vicryl rapide, catgut, monocryl, PDS) which dissolve in the body. Additionally, sutures are classified by thread structure: monofilament sutures (single thread, lower infection risk, require 6-8 knots) and multifilament sutures (multiple threads, higher infection risk, require 2-3 knots). A useful mnemonic is that sutures with 'G' in their name (like catgut, glycolic acid) are typically absorbable.

Polyester suture is a non-absorbable suture material. Non-absorbable sutures remain in the body indefinitely and are used when permanent closure is needed. Other options like silk, monocryl, vicryl, and chromic catgut are absorbable sutures that the body can break down over time.

PDS (polydioxanone) is a synthetic monofilament suture with predictable absorption: larger sizes maintain 80% strength at 2 weeks, smaller sizes 60%, with full absorption at 26-34 weeks. Suitable for bowel anastomoses, fascial closures, and ligament/tendon repairs. Vicryl (polyglactin 90/10) provides 75% strength at 2 weeks, 50% at 3 weeks, 25% at 4 weeks, with full absorption at 8-10 weeks. Indications include deep tissue closure and bowel anastomoses. Monocryl (with epsilon-caprolactone) loses strength rapidly: 50-60% at 1 week, 20-30% at 2 weeks, with full absorption at 13-17 weeks. Suitable for deep tissue and skin closure where rapid absorption is acceptable.

Sutures are classified as absorbable (natural: catgut 90 days absorption, 21-28 days tensile strength; synthetic: Monocryl, Vicryl, PDS 180 days) or non-absorbable (silk, prolene, nylon). Natural sutures cause more tissue reaction. Braided sutures (Vicryl) have higher infection rates. PDS is monofilament with 180-day absorption. Selection depends on tissue type, location, and patient factors.

For the first throw, place your index finger underneath the string, then make a loop with the string in your left hand. Connect your thumb with your index finger and push your thumb through the loop. Place the string from your left hand between your thumb and index finger, then pull it through. Since the starting position is already crossed, you do not need to cross your hands for the first throw.

The Square Knot is created by alternating over-under movements between two cords. Starting with the left cord, go over the middle cord and under the right cord. Then take the right cord and go under the middle cord and over the left cord. Repeat this pattern to create a flat, symmetrical knot that lies flat against the work surface.

The square flat knot is a fundamental weaving technique where two cords are folded in half, tied together with a knot leaving a loop, then secured on a firm surface; the plaiting process involves alternately placing one cord over the center cords and tucking its tail under the crossed cords into the loop, working from the side where the loop appears and maintaining even tension to prevent curling, with errors easily corrected by gently pulling the cords apart.

The one-handed square knot tying technique involves two throws: the first throw uses the index finger and thumb to form an 'okay' sign with the suture, then the middle finger catches the strand on its back side while pinching between middle and ring fingers, rotating the hand under the bridge to pull the suture through; the second throw uses three fingers to form a 'C' shape, pinches between thumb and middle finger, crosses over the index finger, flexes the index finger to catch the suture, and rotates the hand out to pull it through, with hands crossed during the second throw to create square knots.

To tie a square knot using the one-hand technique, position your thumb and index finger to hold the palm while extending three fingers underneath the blue string; create a loop over the three fingers, then take the middle finger over the white string underneath the blue, grab it between the third and fourth fingers through the loop, pull the blue string away from you, form a triangle by placing the index finger underneath, grab the string, and tie to complete the square knot.

Proper instrument handling is essential for safe and effective surgery. Forceps should be held between thumb and middle fingers for control, with index finger providing stability and ring/pinky fingers planted on the surface for support. Flat-tipped forceps (DeBakey) should not be used on skin to prevent crush injuries; pointed tips are preferred. Needle drivers can be held traditionally (ring finger in bottom loop, thumb in top), palmed (without fingers in loops for better pronation/supination), or with intermediate variations. Needles should be loaded two-thirds back from the tip with slight outward angle, and protected by rotating the point against the shaft when returning to assistants. Scissors must be held with screws pointing upward, blades pushed together with thumb and ring fingers, and entered with blades closed to prevent inadvertent cutting.

The needle driver (Portekü) is held in the dominant hand and grips the needle's back portion, with 1/3 behind and 2/3 in front. The forceps (Penset) is held in the non-dominant hand to grip tissue. For suturing, the needle enters at a 90-degree angle from the wound edge, 2-3mm from the margin. The needle driver should not grip the needle tip to prevent tissue damage. The needle is withdrawn by gentle rotation rather than direct pulling. Knots are tied 10-15cm from the wound, with tails left at appropriate length for secure knotting.

Proper surgical technique begins with correct instrument handling. The thumb should only touch the tip of the needle driver hole, not the entire hole, to maintain full range of motion and enable easy removal. Palming the instrument involves using the thumb pad to disengage the ratchet without fingers entering the rings, facilitating easier handoff to surgical techs and supination in line with the forearm. For Castro Viejo needle drivers, two grips exist: palm grip with forearm supination, or pencil grip with rolling between fingers. Scissors should also avoid thumb placement in holes. Suture preparation requires understanding cord length—the distance from needle tip to suture attachment—and bisecting this length with the incision to ensure equidistant entry and exit points. Supination of the arm during suturing allows deeper tissue to help avert the wound. The first knot should be a surgeon's knot with two loops, followed by single-loop knots. Tension must bring wound edges together without strangulating tissue.

Proper surgical instrument handling is essential for safe and effective suturing. Needle drivers lock in place and should be operated using the body or hand rather than placing the thumb in the hole. pickups (not tweezers) are specialized forceps with teeth on the ends that help grip tissue during suturing. These instruments are used to hold and manipulate tissue precisely. Surgeons must practice the locking mechanism of needle drivers and understand the difference between pickups and regular tweezers for proper tissue approximation.

This comprehensive section covers essential surgical instrument selection and handling. Needle holders serve three functions: holding needles securely, grasping during tissue passage, and manipulating needle curves. Selection depends on needle size—larger needles require wider holders, while delicate tissues need finer instruments. Four grip techniques exist: palm grip (maximum power, poor release), thanar grip (easy release, pops apart), thumb-ring finger grip (precision, preferred), and pencil grip. Consistent practice of one technique builds foundational skills. Tissue forceps vary by application: Debakeys for delicate tissues, Adson-Browns for skin (avoid if possible). Hold forceps like finger extensions for optimal control. Proper needle placement on the driver requires 90-degree positioning with thumb and ring finger grip. Wrist positioning and needle curve utilization are critical for controlled passage. Palming the needle enables continuous rotation without releasing, but requires stable tissue. Always visualize the needle tip throughout—animal skin elasticity varies significantly between species and breeds, and conditions like cutaneous asthenia cause abnormal stretching. Losing a needle under tissue can be disastrous.