How to – Mass Removal

Indications

Mass removal is indicated for known and suspected tumors. Excisional biopsy works well in many situations in which full mass removal is possible. Portion of the mass is submitted for histopathology. Follow-up treatment may or may not be needed.

Relevant anatomy

Masses should be removed along the lines of tension.

To find lines of tension – pinch the skin.  Try again at a slightly different angle. The angle at which it is easiest to pinch up skin (skin seems loosest) is the same angle in which you should make the incision. Try this on the dorsal surface of your forearm. Lines of tension run longitudinally.

Preoperative management

Food restrictions: NA if performed standing. If under general anesthesia, food does not need to be withheld in horses but should be withheld for 24-48 hours in adult ruminants.

NSAIDs/analgesics: Preoperative NSAIDs or narcotics are used to prevent pain windup.

Antibiotics: Often not required. Preoperative antibiotics may be indicated in contaminated environments or when surgery involves the GI tract, respiratory tract or urogenital tract.

Tetanus prophylaxis is recommended in horses. 

Local blocks: Regional blocks are often used to circumscribe the mass to be removed.

Position/preparation: Standing sedation is preferred when possible. Local blocks may be all that is required in cattle.  Presuturing for 2-8 hours may help stretch skin for larger masses.

Surgery Supplies: 

• Scalpel and handle
• Hemostats
• Metzenbaum scissors
• Thumb forceps
• Needle holders
• Suture – 2-0 to 3-0, cutting needle for skin
• Suture – 2-0 to 3-0 taper needle for subcutaneous tissues
• Penrose drain (optional)
• Formalin for histopathology

Surgical procedure

• Treat the tumor as an abscess to prevent exfoliation of tumor cells into the surgery area. Drape it off from the surgery field.
• A fusiform incision is made around the mass, long axis along the lines of tension. The length should be approximately 4x the width needed to remove the mass. [Margins should be 2-3cm if tumor type is unknown or malignant; benign tumors can have minimal margins.]

• The subcutaneous tissues are dissected using sharp dissection, freeing the mass from the underlying tissues. Careful attention to hemostasis helps prevent release of tumor cells into the circulation. If the tumor is attached to other tissue structures, those structures should be removed, if possible.

• Change gloves and drapes prior to closure.
• Subcutaneous closure may be skipped; alternately a simple continuous pattern is used to close deadspace. If combined with chemotherapy, use a long lasting monofilament suture.
• If the deadspace is large, a penrose drain may be placed. Other options include deeper suture layers to close the space; mesh expansion of the skin to allow fluid to drain while still permitting closure; and pressure bandages.
• Skin closure
  • Routine – simple continuous or Ford interlocking
  • Options for closure under tension
    • Start closing from both ends
    • Tension relief sutures in key parts – NFFN, vertical mattress or horizontal mattress
    • Undermine tissues to allow stretch
    • Relief incisions
    • Secure knots by first placing granny knots or using 3 throws rather than 2 for the surgeon’s knot. Follow with a square knot. The granny knot can be tightened with the later throw meaning you can tighten down in two steps. Three throws provides more friction that keeps the knot in place.

• Place a stent over the incision or bandage the area if needed to compress deadspace.

Postoperative care

• Minimize motion for 3-5 days and then limit motion until suture removal.
• Suture removal in 10-14 days.
• NSAIDs for 3 days will help minimize swelling

Complications

• Dehiscence (usually about day 3)
• Infection
• Tumor recurrence
• Poor healing (tumor cells at wound margin)

Videos

Mass removal and closing wounds under tension

Standing version

Heifer Mass-ectomy w/captions

Resources

Using a callicrate bander to remove a pedunculated mass on a bovine – video  |  video w/captions

Surgical Management of Equine Neoplasia, Vet Clin Equine 40 (2024) 371–385– another useful review and how-to guide