surgical implants

Implanted Materials Live Session

• Alison Livesey, October 2024

Case Study 1: George the Labrador

• One-year-old male
• Vomiting for one week
• Has not eaten anything in a week
• Frequently eats stones
• Admitted for radiographs showing a foreign body in the intestines
• Suspected exploratory laparotomy due to sharp object and potential perforation
• To be stabilized and taken to surgery following stabilization.

Suture Materials and Considerations

• Suitability of suture materials for enterotomy/enterectomy
• Neighbor- absorbable? Non-absorbable?
• Needle type and size
• Suture pattern (monofilament/multifilament)

Prolene-Polypropylene

• Synthetic material, non-absorbable
• Long-term strength retention
• Poor handling, high memory
• Not suitable for intestinal repair
• Reverse cutting needle not suitable

Vicryl/Polyglactin 910

• Synthetic braided/multifilament material, absorbable
• Absorption time: 56-70 days
• Loss of strength occurs over the time period of absorption
• Used for ligation/tissue approximation
• Braided structure is more likely to wick bacteria
• Reverse cutting needle not suitable

Chromic Cat Gut

• Natural material/absorbable
• From cattle/sheep mucosa & submucosa
• Excellent handling, but can elicit a foreign body reaction.
• Loss of strength occurs over the time period of absorption
• Full absorption occurs in 42 days
• Loses strength more rapidly if infection is present
• Not suitable for intestinal anastomosis
• Swaged needle needed for anastomosis

PDS Polydioxanone

• Synthetic absorbable monofilament
• Less wicking than multifilament
• High memory
• Useful where prolonged support required
• Predictable absorption time: 180 days
• 14-20% loss at 14 days, 41%-50% loss at 42 days, 86% loss at 56 days
• Round-bodied needle

Needle Evaluation

• Problematic needle examples shown on slides
• Requirements for proper needle shape and fixation (swaged needle)

Suture Patterns for Enterotomy/Enterectomy

• Simple interrupted or continuous patterns suitable for enterotomy/enterectomy.

Patient Considerations for Surgery

• Hypovolemia
• Hypoproteinaemia
• Hypothermia
• Break in asepsis
• Contaminated procedure and spillage
• Analgesia
• Halsted's principles (aseptic technique, preserving blood supply, minimized tension, accurate tissue apposition, minimized dead space, haemostasis)

Surgery on George

• Removal of sharp pebble (foreign body) and successful end-to-end resection performed.

Wound Classification

• Categories include clean, contaminated, and dirty. Different wound classifications.

Case Study 2: Two-year-old Female DSH Cat with Suture Issue

• Owner noted suture hanging from wound following midline spay.
• Simple continuous pattern was used in the linea alba during prior surgery.
• Potential patient factors (immune system, hydration, co-morbidities)
• Potential surgical factors influencing suture failure (wrong size/type of material, incorrect suture pattern, improper placement).
• Cat had fluid in the abdomen, suggesting another underlying cause for the issue.

Case Study 3: Three-year-old MN Shih Tzu

• Grade 3 patellar luxation surgery 4 weeks prior.
• Tibial tuberosity transposition.
• Swelling developed over stifle following the operation.
• Corrective measures needed.

Case Study 4: Four-year-old FN DSH Cat

• Urinary straining, hematuria, and presence of calcium oxalatecrystals.
• Radiographs reveal calculus in the bladder.
• Cystotomy procedures

Suture Material for Cystotomy

• Stay sutures to suspend the bladder and prevent abdominal contamination.
• Synthetic absorbable material (polydioxanone/polyglactin) 25/3/0 or 4/0 (1.5/2 metric).
• Two-layer closure recommended if possible.
• Inverting suture for water-tight closure.

Inverting Suture Patterns

• Lembert
• Connell
• Cushing
• Detailed techniques illustrated on images.

Polyglactin 25 (Monocryl) Sutures

• Synthetic absorbable
• Monofilament
• Rapid absorption: 91-119 days.
• Quicker loss of strength than polydioxanone.
• 30-50% strength loss at 7 days.
• Knot security less reliable than multifilaments.

Case Study 5: Stray Persian Cat After RTA

• X-rays revealed no abdominal injuries
• Further investigations needed for possible concealed injuries

Radiograph Interpretation

• Determining anatomical structures or foreign bodies from X-Ray images

Sub-Ureteral Bypass Procedure

• Description of the procedure
• Use for repair of ureteral damage
• Illustrative images of the procedure presented

Case Study 6: Charlie-4 year old female Pointer

• Not eating for a week
• Diagnosis of pancreatitis
• Procedure requires oesophagostomy tube placement.
• Suture needed to hold the oesophagostomy tube in place

Chinese Finger Trap Suture

• Description of the procedure
• Uses to secure tubes (drains/feeding)

Feeding Tubes

• Nasogastric tubes
• Oesophagostomy tubes
• Gastrotomy tubes

Normal Stomach

• Features of a normal stomach on x-ray and images

Gastric Dilation

• Diagnostic indicators
• Images illustrating presence of stomach and/or gas

Gastric Torsion

• Description of the anatomical rotation of organs in the digestive system
• Treatment techniques for gastric torsion.
• Suture types frequently employed for gastropexy

Purse String Suture

• Temporary closure used for structures like the anal region.
• Securing tubes

Implant Problems in Animals

• Identification of possible issues with implant, such as infections
• Images illustrating potential complications

Ameroid Constrictor

• Medical device for controlling the size of an internal anatomical structure, such as in the digestive system.

Summary of Suture Characteristics

• Summary of suture classifications (absorbable/non-absorbable, synthetic/natural, monofilaments/multifilaments).
• Important properties and considerations regarding suture selection.

Size Guides

• Conversion between metric and USP sutures