Abdominal surgery
3.17 Liver biopsy Indications
Estimation of Cu, and trace element concentration; diagnosis of fatty liver and other hepatic pathology.
Technique
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clip and disinfect area 15 × 15 cm, centred on 11th (10th in very long-backed cattle) right intercostal space and 20 cm ventral to vertebrae.Check site by percussion for area of hepatic dullness (see Figure 3.24)
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produce local analgesia of skin and intercostal musculature by infiltration of 5–10 ml 2% lignocaine•
make 1 cm stab incision in skin and musculatureR13 R12
R11R10 5
2 1
4 3
Figure 3.24 Diagram of right side of abdominal wall of cow, showing site of hepatic dullness. Cranial boundary is usually around rib 9. In severe hepatomegaly caudal border may be palpable behind last rib. Site for hepatic biopsy is about one third of distance down rib cage. (From Smart & Northcote, 1985.)
1. lung; 2. liver; 3. right kidney; 4. gall bladder; 5. phrenico-costal line; X site of liver biopsy.
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insert trocar and cannula (20 cm long, 6 mm external diameter, see Appendix 3 for manufacturers) through incision, through intercostal muscle•
perforate parietal peritoneum (palpable sensation, also pain reaction likely in animal) to contact liver surface•
withdraw trocar and advance cannula at angle of 70° to horizontal and 20° cranially (i.e. slightly downwards and forwards, aiming towards left elbow) using slightly rotating action•
if necessary, partly withdraw cannula and repeat in slightly changed direction: characteristic soft grinding sensation is appreciable on passage through liver•
attach adapter and syringe (tight fit essential), and using continuous negative pressure, twist and then withdraw cannula and contained tissue•
expel tissue (typical specimen 4 cm × 4 mm diameter) onto dry gauze swab by positive pressure, or reinsertion of trocar•
dress skin wound with dry antibiotic powder, suture unnecessary. Pro-cedure may be safely repeated at weekly intervals. Manufacturer of biopsy instrument is given in Appendix 3, pp. 262–265.Complications
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accidental entry into hepatic vessel – immediate bleeding from cannula.Avoid by stopping advance of cannula should any firm structure (namely perivascular fibrous tissue) be encountered, and changing direction slightly
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accidental entry into hepatic abscess with gross peritonitis•
localised peritonitis – dirty technique•
wound infection – dirty technique 3.18 Anal and rectal atresia IntroductionAnal and rectal atresia (imperforate anus) in the calf are rare, anal atresia being more frequent. Inheritance of this lethal defect in cattle is not estab-lished. Other defects e.g. taillessness and spinal dysraphia may co-exist.
Diagnosis
Usually made at two to three days old unless stockman has made meticulous, neonatal examination. Absence of faeces draws attention to calf which may have slightly distended abdomen.
Perineum has a scar indicative of anal orifice. In anal atresia scar may overlie a slight bulge of the subcutaneous tissues, and becomes more pro-nounced on increased intra-abdominal pressure, applied by pushing on the flanks or by spontaneous tenesmus. Absence of such a bulge suggests that rectal atresia may also be present.
Investigation of differential diagnosis between atresia involving anus alone and both anus and caudal rectum depends on surgical exploration.
Surgery
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operate as soon as possible under caudal epidural analgesia (1 ml 2%lignocaine plain)
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cleanse and clip area 10 cm diameter around anus•
remove 1 cm diameter circle of skin over anal scar•
retract skin edges with Allis forceps held by assistant•
in anal atresia a distended blind-ended rectum is easily located by digital exploration in pelvic midline•
attempt to suture rectal wall to skin at this stage•
otherwise gently break down surrounding connective tissue and attempt to exteriorise the caudal portion of rectum•
place four stay sutures dorsally, ventrally and bilaterally into rectum to maintain in position and then incise this vertically for 1–2 cm; meconium will spurt from lumen•
suture rectal margin to skin in simple interrupted sutures of 4 metric chromic catgut, starting with two dorsal sutures at eleven o’clock and one o’clock positions, followed by two ventrally at seven o’clock and five o’clock•
add additional sutures laterally•
avoid as far as possible contamination of subcutis and, more important, the pelvic cavity•
remove extra-rectal meconium with damp swabs and do not irrigate wound which could flush infection cranially•
inject systemic antibiotics (five days)•
maintain a lumen, minimum 2 cm diameter, which may require dilata-tion several weeks later as initial healing results in localised fibrosis•
milk diet for two weeks•
do not use for breeding Rectal atresia TreatmentCalves with additional atresia involving the rectum may prove difficult to assess, and impossible to correct without the creation of a low flank caecal fistula (preternatal anus) which, though possible experimentally, cannot be justified on economic, practical and animal welfare grounds. Cicatricial stricture is a common post-operative result.
Slight rectal atresia, with the rectum terminating 2 cm cranial to the anus, is treated by careful blunt dissection dorsally involving the mesorectum;
suture to skin as for anal atresia.
Unfortunately in many cases the integrity of the blood supply is seriously impaired by inadvertent tears and stretching of the mesorectum, causing mural necrosis followed by rupture of the rectal wall and fatal faecal peri-tonitis extending from the pelvic cavity into the abdomen. Euthanasia is therefore advisable in cases of anal and rectal atresia which involve absence of at least 3 cm of terminal rectum.
3.19 Rectal prolapse