By F. A. (Tony) Mann, DVM, MS, Dipl. ACVS, Dipl. ACVECC For The Education Center
Originally published in Veterinary Practice News, April 2015 – Download as a PDF
Surgery has multiple roles to play in oncology, including prevention, diagnosis, palliation, and cure, either alone or as an adjunct to other oncological therapies. The carbon dioxide laser can be a handy surgical tool to perform these roles.
Hemostasis provided by laser incision helps maintain a clear surgical field, greatly enhancing the surgeon’s ability to observe surgical planes and obtain proper surgical margins around the tumor. Because of the bloodless field, laser excisions can be a bit more conservative than the conventional scalpel.
In other words, one can cut closer to the neoplasm without encroaching it.
Of course, sound oncological surgical principles of obtaining wide margins should not be compromised, but a bloody field often causes the surgeon to go wider and deeper than necessary to make sure the tumor is excised without seeing it, a notable goal of wide excision surgery.
When excisional biopsy is the goal, as opposed to wide excision, the laser again allows closer excision. Some laser artifact may be noted on histopathology, but the artifact does not interfere with diagnosis or examination of margin completeness, unless tumor cells abut the laser coagulated tissue, in which case one would question the comfort level of the excision anyway.
Many surgeons use electrosurgery for coagulation and incision during excisions of neoplasms. Electrosurgery remains desirable for coagulation because an active bleeder will not be coagulated by the laser. One can use the laser to tissue weld vessels and then cut them, but once the vessel is cut and bleeding, the carbon dioxide laser will be ineffective since it does not penetrate blood, accumulated tissue fluids, saline, etc.
Electroincision has been used in deep tissues for surgical excisions to minimize hemorrhage such as occurs when one cuts through muscle. However, the electrical stimulation causes rather dramatic muscular activity. A similar (even better – less jagged) bloodless incision of muscle can be achieved by using the laser with the additional advantage that the laser causes no muscle contraction. An occasional quiver may be noted when the laser hits muscle, but the muscle is essentially quiet.
One drawback to laser excision is length of surgery time. The limited depth of penetration of the carbon dioxide laser necessitates several passes to get through certain tissues such as skin. For that reason, it is common to make the skin incision with a standard scalpel, achieve hemostasis with electrosurgery, and then deepen the incision and dissect through subcutaneous and deep tissue planes with the laser.
The laser may be used with thin skin (cats), mucosal surfaces, and small skin mass excisions without significant increases in surgical time, and, in fact, surgery time may be shorter than conventional scalpel in these circumstances.
Following are six clinical case examples of using the carbon dioxide laser in oncological surgery.
CASE 1: A 5-year-old spayed Australian cattle dog diagnosed with lingual melanoma.
CASE 2: An 11-year-old spayed domestic short-haired cat presented for excisional biopsy.
CASE 3: A 9-year-old neutered husky presented for partial maxillectomy.
CASE 4: An 8-year-old spayed Labrador retriever presented for excison of a right perianal mastocytoma
CASE 5: A 7-year-old spayed mixed breed dog presented for wide excision of suspected mastocytoma from lateral right pelvic limb.
CASE 6: An 8-year-old neutered domestic short-haired cat with vaccine-induced fibrosarcoma
Dr. F. A. (Tony) Mann is a tenured full professor in the Department of Veterinary Medicine and Surgery at the University of Missouri, Columbia, Mo. In addition to teaching and research responsibilities, he practices at the University of Missouri Veterinary Medical Teaching Hospital, where the cases described herein were treated. Dr. Mann is a diplomate of the American College of Veterinary Surgeons and a diplomate of the American College of Veterinary Emergency and Critical Care. Dr. Mann obtained his DVM from the Ohio State University (1982), completed a rotating internship at the University of Missouri (1983), and completed a small animal surgery residency with M.S. degree from Texas A&M University (1986). He served on the faculty at Auburn University from 1986 to 1988, and has been on the faculty at the University of Missouri since 1988.
This Education Center article was underwritten by Aesculight of Bothell, Wash., manufacturer of the only American-made CO2 laser.