Surgery Marrow Pg 11-20 (General Surgery)

Natural Non-Absorbable Sutures

• Silk is a black, braided suture derived from the silkworm.
• Silk is used for skin closure, drain fixation, and second-layer bowel anastomosis.
• Prolene is a blue monofilament suture.
• Prolene sutures are used for hernia mesh, abdominal sheath closure, vascular repair/anastomosis, and aortic, femoral, and popliteal artery repair.
• Nylon/Ethilon is a monofilament suture used for skin suture, cataract surgery, and nerve and tendon repair.
• Steel sutures are used for sternotomy incision following coronary artery bypass grafting (CABG).
• Polyester/Ethibond is used for rectus sheath closure and tendon repair.
• Polybutester is rarely used and has applications in plastic surgery.

Classification of Sutures

• Natural sutures, such as silk and catgut, are made from animal sources.
• Synthetic sutures, such as Prolene and PDS, are manufactured from synthetic materials.
• Monofilament sutures are composed of a single strand and examples include catgut, Prolene, PDS, nylon, and Monocryl.
• Braided sutures are made from multiple strands intertwined and examples include Vicryl and silk.

Suture Removal

• Non-absorbable sutures are removed based on location:
  • Scalp: 5-7 days
  • Face: 3-5 days
  • Neck: 5-7 days
  • Thorax: 10-12 days
  • Abdomen: 12-14 days
  • Perineum: 10-12 days

Bowel Anastomosis

• Inverted edges are preferred for bowel anastomosis.
• The submucosa is the strongest layer in bowel anastomosis.

Surgical Drains

• Different types of surgical drains are used to manage surgical site drainage, including Jackson-Pratt, Penrose, and wound vacuum systems.

Post Operative Fever

• The most common cause of post-operative fever on day 1 is atelectasis, followed by pneumonia.
• Superficial thrombophlebitis and urinary tract infections (UTI) are common causes of post-operative fever on days 2-3.
• Surgical site infections (SSI) and deep vein thrombosis (DVT) are likely causes of post-operative fever on days 4-5.
• Chest physiotherapy, including incentive spirometry, is crucial to prevent post-operative atelectasis and pneumonia.
• Pain control, treatment of congestive heart failure (CHF) and chronic obstructive pulmonary disease (COPD), steam inhalation, and smoking cessation are important for post-operative recovery.

Natural Absorbable Sutures

• Catgut is derived from sheep's gut and is absorbed within 7-10 days by phagocytosis and enzymatic degradation.
• Chromic catgut has a tensile strength of 21-28 days and is completely absorbed within 90 days.

Synthetic Absorbable Sutures

• Monocryl (polyglecaprone) is a monofilament suture used subcutaneously in sizes 3-0/4-0 cutting/reverse cutting needles.
• Vicryl (polyglactin) is a braided suture that dissolves in 60-90 days and is used for common bile duct repair, bowel anastomosis, and bladder closure.
• Polydiaxone (PDS) is a monofilament suture that dissolves in 180 days and is used for the same applications as Vicryl, as well as tracheobronchial repair.

Surgeon & Surgical Factors Contributing to Wound Infection

• Midline incisions are associated with a higher risk of infection compared to transverse incisions.
• Emergency surgeries carry a higher risk of infection than elective ones.
• Continuous sutures have a higher risk of infection than interrupted sutures.
• Long suture bites (1 cm) are preferable to short bites (0.5 cm), as they reduce the number of sutures and the risk of infection.
• Shorter suture lengths are recommended, with a rule of thumb being that the suture length should be at least four times the wound length (Jenkins' theory).
• In cases of rectus sheath closure, non-absorbable sutures are preferred over absorbable sutures.
• Polydioxanone suture (PDS) is commonly used for delayed absorbable sutures in children.

Intra-abdominal Abscesses

• Intra-abdominal abscesses are most commonly found in the pelvis/pouch of Douglas.
• For supine patients, the Morrision pouch/right hepatorenal pouch is a frequent location for an abscess.
• In ambulatory patients, the pelvis/pouch of Douglas is the most likely site.
• Clinical features of an abscess include fever, chills, and rigors.
• Imaging studies, such as a contrast-enhanced computed tomography (CECT) of the abdomen, are essential for diagnosis.
• The most common initial treatment for an intra-abdominal abscess is drainage with a pigtail catheter under ultrasound guidance.

Knot Types for Suturing

• The most basic knot is the square/reef knot, consisting of one square throw followed by another square throw.
• The direction of the crossings in the square/reef knot is crucial. Crossings can be the same (black over pink) or opposite (black/pink).
• A granny/slip knot should be avoided as it does not cross correctly and can easily come undone.
• A surgeon's knot utilizes two throws followed by one single throw, providing greater initial security.

Skin Suturing

• Skin sutures should be placed with everted edges and entered at a 90° angle.
• Each suture bite should be equal, and the distance between two adjacent sutures should be twice the size of a single suture bite.

Types of Sutures

• Simple sutures do not cause eversion; they are used deep within the tissue or for internal closure.
• Mattress sutures, such as the vertical and horizontal mattress stitches, cause eversion and provide hemostasis.
• Subcuticular sutures are placed under the skin for a cosmetically better result, minimizing scarring and marks.
• Other suture types include:
  • Aberdeen's knot/Cobbler's knot: Used for a continuous suture with locking, distributing tension across the wound.
  • Continuous suture
  • Interrupted suture
  • Buried mattress suture
  • Lock suture
  • Purse-string suture

Needles

• Round body needles are ideal for delicate structures such as the bowel, bladder, blood vessels, and the common bile duct, as they split tissue without trauma.
• Cutting/reverse cutting needles dissect through tough structures like the sheath, skin, and fascia.
• Needles have specific parts:
  • Point (needle tip)
  • (2/3rd or 1/3rd) rd section (needle body)
  • Swaged end (suture material attachment)
  • Body (shaft)
  • Needle holder

Suture Color Coding

• Identifying the suture type is essential for appropriate surgical procedures. Color coding helps:
  • Brown - catgut
  • Violet - Vicryl
  • Blue - Prolene
  • Black - silk

Suture Numbering

• Sutures have a numbering system based on diameter:
  • No 1 - thickest
  • 11.0 - finest

Deep Vein Thrombosis (DVT)

• DVT is a venous thromboembolism (VTE) that occurs in the deep veins of the lower extremities, more commonly than the upper limbs.
• Clinical features of DVT include unilateral lower limb swelling, pain, and tenderness.
• A duplex scan is the gold standard for diagnosing DVT.
• Mechanical prophylaxis for DVT includes early ambulation, preventing stasis, and pneumatic stockings.
• Pharmacological prophylaxis for DVT typically involves low molecular weight heparin.

Burst Abdomen/Abdominal Wound Dehiscence

• Burst abdomen occurs when the rectus sheath opens, exposing the bowel.
• Common symptoms include a cough on day 6 after surgery, a soaked dressing with reddish fluid, and the serous/salmon fluid sign.
• Emergency management involves repositioning the bowel and using a urobag/Bagota bag laparostomy.
• Definitive treatment includes resuturing of the rectus sheath in an operating room (OT) setting.
• Factors predisposing to burst abdomen include chronic cough, constipation, infection, obesity, immunocompromise, and malnutrition.

Obliteration of Large Cavities

• Sutures are commonly used to obliterate large cavities during surgical procedures.