How to perform a surgical hepatic biopsy - Veterinary Medicine
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How to perform a surgical hepatic biopsy
An open surgical method greatly improves your chances of obtaining a diagnostic liver biopsy sample. The specific biopsy technique you should use depends on the site from which you are sampling.


VETERINARY MEDICINE


Peripheral or diffuse lesions


Figures 3,4
The guillotine method is used to sample the hepatic margin of pointed or sharp-edged lobes. Form a loop with 3-0 absorbable monofilament suture, using a single throw. Drop the suture loop over the point of the lobe, settling the suture into a natural fissure or in notches made by Kelly forceps (Figure 1). Tighten the suture completely so that it crushes all of the tissue within the loop, leaving the piece of tissue attached only by vessels and ducts (Figure 2). While tightening, do not pull the suture outward or upward, as this may sever the vessels and ducts and accidentally remove the ligature with the sample. A second throw can be placed to form a knot but is not necessary for hemostasis and can increase the risk of tearing the vessels. Transect tissue 2 to 3 mm distal to the suture from the lobe with Metzenbaum scissors or a scalpel blade. If you use a blade, place a finger under the piece of liver to be removed, and press the blade gently and firmly through the tissue toward the finger (Figures 3 & 4). If you press slowly but firmly with the flat portion of the cutting edge, you will easily cut through the liver tissue but will not damage your gloves. Trim the suture ligature short. To avoid iatrogenic specimen artifacts, do not use tissue forceps to handle the tissue sample.2,3 Excessive bleeding can be controlled with pressure, ligation, or cautery.2,4


Figures 5,6,7,8
For marginal lesions on rounded liver lobes, place two parallel, full-thickness guillotine sutures perpendicular to the liver margin around the proposed site by using absorbable suture with a swaged needle (Figures 5-8). Leave the ends of the second suture knot long, and then pass one end of the suture around the base of the tissue pedicle and tie it back to the other end (Figures 9 & 10). This will crush the tissues across the base of the pedicle, resulting in hemostasis along all three sides of the tissue sample. Tighten the sutures completely so that they cut through the tissues, and remove the tissue within the suture box with scissors (Figures 11 & 12).

Central lesions


Figures 9,10,11,12
Samples from nonmarginal liver can be obtained with a skin biopsy punch, Tru-Cut biopsy needle, or laparoscopic clamshell biopsy instrument.12 To avoid nicking the large, dorsally located hepatic veins, take the sample, preferably, from the ventral hepatic surface, and do not let it exceed half the thickness of the lobe.

When taking biopsy samples of the liver with clamshell forceps, place the instrument against the site of interest with the jaws open. Insert the forceps into the parenchyma to the level of the angle of the jaws, and close the jaws. After a few seconds of crushing, twist the instrument until a free piece of tissue is removed. Pulling the forceps straight out of the liver tends to cause more hemorrhage than twisting.12

Hemorrhage from punch, Tru-Cut, or clamshell biopsy sites can be controlled by a variety of methods. Absorbable gelatin foam (Gelfoam—Pharmacia & Upjohn) can be inserted into the defect, a mattress suture of 3-0 absorbable material can be placed gently around the defect, or an omental flap can be sutured over the defect. Alternatively, pressure can be applied to the site, or the site can be cauterized by using a low setting.4,13 Thoroughly lavage the abdomen with a balanced electrolyte solution in patients with bile leakage, excessive hemorrhage, or infected or necrotic lesions.2


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Source: VETERINARY MEDICINE,
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