0016-5107/79/2501-0013$02.00/0 GASTROINTESTINAL ENDOSCOPY Copyright © 1979 by the American Society of Gastrointestinal Endoscopy
Retroperitoneoscopy in dogs Lawrence R. Kaplan, MD Minneapolis, Minnesota
Gary R. Johnston, DVM Robert M. Hardy, DVM St. Paul, Minnesota
Retroperitoneoscopy, an endoscopic procedure which permits visualization of the retroperitoneal contents, was performed on 13 adult dogs. The procedure combines the techniques of retroperitoneal pneumography and peritoneoscopy. The kidneys, ureters, adrenals, vena cava, and aorta were examined. Renal biopsies were obtained under direct vision through the endoscope. Retroperitoneoscopy may have clinical application to the diagnosis and staging of retroperitoneal disease in human patients. The retroperitoneal area has been described as the cemetery of medical reputations. This opinion reflects the difficulty in evaluating retroperitoneal disease. Although noninvasive procedures such as computerized tomograph y l and ultrasound 2 accurately locate most retroperitoneal lesions, exploratory surgery is frequently required for a tissue diagnosis. Whereas the peritoneal contents can be examined and biopsied with fiberoptic instruments, the retroperitoneal area has remained inaccessible to endoscopic investigation. This 'animal study reports an endoscopic technique which permits direct examination and biopsy of the retroperitoneal contents. Fiberoptic retroperitoneoscopy combines the techniques of 2 well-established procedures, retroperitoneal pneumography3-s and peritoneo~copy.6-8
METHODS Retroperitoneoscopy was performed on 13 adult mixed breed and purebred dogs ranging in weight from 15 to 60 kg. Each fasting animal was premedicated with atropine sulfate (0.04 mg/kg), induced with thiamylal sodium (15 mg/kg), intubated, and maintained on a mixture of methoxyflurane and oxygen. All animals were positioned prone and supported with sandbags. A pneumoretroperitoneum was established with nitrous oxide (N 2 0) insufflated through a 20-gauge spinal needle placed presacrally. The needle was inserted midpoint between the root of the dog's tail and anus. Under the control of a finger in the rectum, the needle was guided to the sacrum and then withdrawn slightly. After aspiration to determine that the needle was not in a blood vessel, insufflation was begun using a Wolf automatic N 2 0-insufflator. Following the slow infusion of SOO ml of N 20, a lateral radiograph with a horizontal beam was taken to confirm the location of the gas in the retroperitoneum.
The remainder of the N 2 0 was infused at a rate of 1 liter/minute while the pressure within the retroperitoneal space was maintained between 25 and 30 mm Hg. The volume of N 2 0 used to establish the pneumoretroperitoneum ranged from 5 to 20 liters depending upon the size of the animal. The optimal quantity of gas infused was determined by serial radiographs and by percussion of the lumbar region for tympany. Once the pneumoretroperitoneum was established, the animal's flank was shaved, prepared, and draped. The right flank approach was used in 11 of the 13 dogs. A 1.2-cm horizontal skin incision was made 2 em caudal to the 13th rib and 3 cm ventral to the sublumbar muscles. An 11-mm trocar was then gently pushed through the abdominal muscle layers into the gas-filled retroperitoneum. A 10mm, 170°-vision, Jacobs-Palmer (Wolf) operating peritoneoscope was advanced through the trocar and the retroperitoneal contents were examined (Figure 1). Renal biopsies were obtained under direct vision with a Jacobs' grasping forceps placed through the probe channel of the peritoneoscope. Blunt dissection of thin areolar connective tissue with a hook scissors through the peritoneoscope was frequently required for better visualization. The procedure was terminated by releasing the gas from the retroperitoneum and removing the trocar. The procedure took 30 to 45 minutes in each animal. Six dogs were immediately sacrificed and necropsied. Seven animals were allowed to recover and were observed for complications. RESUL15 Retroperitoneal insufflation with nitrous oxide displaced the retroperitoneal structures ventrally. On a lateral radiographic projection the kidneys were outlined along the peritoneum. The abdominal aorta, vena cava, and ureters were located within the gas-filled retroperito-
From the Division of Gastroenterology, University of Minnesota School of Medicine, Minneapolis, Minnesota, and Department of Small Animal Clinical Sciences, University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota. Reprint requests: L. R. Kaplan, MD, University of Minnesota, Department of Medicine, Box 438 Mayo, Minneapolis, Minnesota 55455. VOLUME 25, NO. 1, 1979
13
neum (Figure 2). Occasionally, the adrenals, renal artery and vein, and the dorsal circumflex iliac arteries could be identified. From the right flank approach the posterior surface of the right kidney was easily visualized through the peritoneoscope (Figure 3A). By careful dissection of perirenal fascia in the hilar area, the renal artery, vein, and ureter
Figure 1. Lateral radiograph of pneumoretroperitoneum established in an adult dog. The endoscope in the air-filled retroperitoneum is directed toward the right kidney (R). Notice the position of the insufflation needle (arrow).
could be identified. Adequate biopsies of renal tissue were obtained under direct vision (Figure 38). The ureter was traced from the renal hilus to the bladder. The vena cava was visualized from the region of the eleventh thoracic vertebra to the third lumbar vertebra (Figure 3Q. The right adrenal could be identified by first locating the phrenicoabdominal artery and vein which lie ventral to the gland near the superior medial surface of the kidney. Visualization of the left kidney and its associated structures required a left flank approach. The aorta was identified as a pulsating structure after careful dissection in the sublumbar area anterior to the iliopsoas muscles. The vena cava, which lies to the right of the aorta, was best seen by the right flank approach. Complications. Retroperitoneal insufflation was accomplished without complication. Insertion of the needle presacrally was unassociated with bleeding, infection, or bowel perforation. Although the volume of insufflated gas in retroperitoneoscopy is 5 to 10 times that used in canine retroperitoneal pneumography,5 perineal, perianal, mediastinal, or subcutaneous emphysema did not occur. The gas which remained in the retroperitoneum after the procedure ended was rapidly absorbed. The trocar with its sharp obturator was inserted into the retroperitoneum with minimal trauma to flank muscle tissue. Six dogs observed for a minimum of 48 hours following retroperitoneoscopy and renal biopsy showed no complications. There was no evidence of infection or significant bleeding at necropsy. Renal biopsy was associated with a 10- to SO-ml blood loss. An attempted biopsy of normal adrenal tissue resulted in the only complication in the series. One animal died 6 hours after the procedure. Necropsy revealed a perforation of a renal vein.
DISCUSSION Retroperitoneoscopy in dogs is a reliable
Figure 2. Lateral radiograph of a pneumoretroperitoneum demonstrating the right (R) and left (l) kidneys, ureters (thin arrows) and aorta (thick arrows).
procedure for examining the retroperitoneal contents. The kidneys, adrenals, ureters, vena cava, and periaortic region can be easily examined. The kidney can be safely biopsied under direct vision. The similarity between the dog and human anatomy below the diaphragm suggests that retroperitoneoscopy may also have important application in the diagnosis of human retroperitoneal disease. Directed biopsy of en-
Figure 3. A, Endoscopic photograph of right kidney (thin arrows) and ureter (thick arrows) taken during retroperitoneoscopy. Clotted blood (H) from a recent renal biopsy lies on the kidney. B, Grasp biopsy of a normal dog kidney obtained under direct endoscopic vision during retroperitoneoscopy (H & E, X 66). C, Endoscopic photograph of right ureter (thin arrows) and vena cava (thick arrows) taken during retroperitoneoscopy.
14
GASTROINTESTINAL ENDOSCOPY
larged periaortic nodes or retroperitoneal masses may provide a necessary tissue diagnosis. Endoscopic renal biopsies may be indicated when a closed biopsy is associated with increased risk. Because the dog's pancreas is intraperitoneal, the value of retroperitoneoscopy in human pancreatic disease could not be studied. Cadaver studies are now underway to further evaluate the procedure. Sound patient management requires a correct diagnosis. Retroperitoneoscopy may enable the endoscopist to make a difficult diagnosis or stage malignant disease without resorting to exploratory retroperitoneal surgery.
ACkNOWLEDGMENTS The authors wish to thank Ms, Nancy Shields, RN, for assistance with the retroperitoneoscopy,
VOLUME 25, NO 1, 1979
REFERENCES 1. STEPHENS DH, WILLIAMSON B JR, SHEEDY PF, ET AL: Computerized tomography of the retroperitoneal space. Radiol Clin North Am 15:377, 1977 2, FREIMANIS AK: Echographic diagnosis of lesions of the abdominal aorta and lymph nodes. Radiol Clin North Am 13:557, 1975 3, RUlz RIUAS M: Roentgenological diagnosis: generalized subserous emphysema through a single puncture, Am / Roentgenol 64:723, 1950 4. STEINBACH Hl, SMITH DR: Extraperitoneal pneumography in diagnosis of retroperitoneal tumors, Arch Surg 70:161, 1955 5. ZESKOV B, PETROVIC B, DRAGNOVIC B: Retropneumoperitoneal visualization of abdominal organs in domestic animals. / Am Vet Rad Soc 17:23, 1976 6. BOYCE HW jR: laparoscopy, in Diseases of the Liver, L Schiff, ed. Philadelphia, IB lippincott, 1975, p, 272 7. BOYCE HW JR, PALMER ED: Techniques of Clinical Gastroenterology. Springfield, Illinois, Charles C Thomas, 1975, p. 147 8, TRUJILLO NP: Peritoneoscopy and guided biopsy in the diagnosis of intraabdominal disease, Gastroenterology 71:1083, 1976
15
Retroperitoneoscopy in dogs Lawrence R. Kaplan, MD Minneapolis, Minnesota
Gary R. Johnston, DVM Robert M. Hardy, DVM St. Paul, Minnesota
Retroperitoneoscopy, an endoscopic procedure which permits visualization of the retroperitoneal contents, was performed on 13 adult dogs. The procedure combines the techniques of retroperitoneal pneumography and peritoneoscopy. The kidneys, ureters, adrenals, vena cava, and aorta were examined. Renal biopsies were obtained under direct vision through the endoscope. Retroperitoneoscopy may have clinical application to the diagnosis and staging of retroperitoneal disease in human patients. The retroperitoneal area has been described as the cemetery of medical reputations. This opinion reflects the difficulty in evaluating retroperitoneal disease. Although noninvasive procedures such as computerized tomograph y l and ultrasound 2 accurately locate most retroperitoneal lesions, exploratory surgery is frequently required for a tissue diagnosis. Whereas the peritoneal contents can be examined and biopsied with fiberoptic instruments, the retroperitoneal area has remained inaccessible to endoscopic investigation. This 'animal study reports an endoscopic technique which permits direct examination and biopsy of the retroperitoneal contents. Fiberoptic retroperitoneoscopy combines the techniques of 2 well-established procedures, retroperitoneal pneumography3-s and peritoneo~copy.6-8
METHODS Retroperitoneoscopy was performed on 13 adult mixed breed and purebred dogs ranging in weight from 15 to 60 kg. Each fasting animal was premedicated with atropine sulfate (0.04 mg/kg), induced with thiamylal sodium (15 mg/kg), intubated, and maintained on a mixture of methoxyflurane and oxygen. All animals were positioned prone and supported with sandbags. A pneumoretroperitoneum was established with nitrous oxide (N 2 0) insufflated through a 20-gauge spinal needle placed presacrally. The needle was inserted midpoint between the root of the dog's tail and anus. Under the control of a finger in the rectum, the needle was guided to the sacrum and then withdrawn slightly. After aspiration to determine that the needle was not in a blood vessel, insufflation was begun using a Wolf automatic N 2 0-insufflator. Following the slow infusion of SOO ml of N 20, a lateral radiograph with a horizontal beam was taken to confirm the location of the gas in the retroperitoneum.
The remainder of the N 2 0 was infused at a rate of 1 liter/minute while the pressure within the retroperitoneal space was maintained between 25 and 30 mm Hg. The volume of N 2 0 used to establish the pneumoretroperitoneum ranged from 5 to 20 liters depending upon the size of the animal. The optimal quantity of gas infused was determined by serial radiographs and by percussion of the lumbar region for tympany. Once the pneumoretroperitoneum was established, the animal's flank was shaved, prepared, and draped. The right flank approach was used in 11 of the 13 dogs. A 1.2-cm horizontal skin incision was made 2 em caudal to the 13th rib and 3 cm ventral to the sublumbar muscles. An 11-mm trocar was then gently pushed through the abdominal muscle layers into the gas-filled retroperitoneum. A 10mm, 170°-vision, Jacobs-Palmer (Wolf) operating peritoneoscope was advanced through the trocar and the retroperitoneal contents were examined (Figure 1). Renal biopsies were obtained under direct vision with a Jacobs' grasping forceps placed through the probe channel of the peritoneoscope. Blunt dissection of thin areolar connective tissue with a hook scissors through the peritoneoscope was frequently required for better visualization. The procedure was terminated by releasing the gas from the retroperitoneum and removing the trocar. The procedure took 30 to 45 minutes in each animal. Six dogs were immediately sacrificed and necropsied. Seven animals were allowed to recover and were observed for complications. RESUL15 Retroperitoneal insufflation with nitrous oxide displaced the retroperitoneal structures ventrally. On a lateral radiographic projection the kidneys were outlined along the peritoneum. The abdominal aorta, vena cava, and ureters were located within the gas-filled retroperito-
From the Division of Gastroenterology, University of Minnesota School of Medicine, Minneapolis, Minnesota, and Department of Small Animal Clinical Sciences, University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota. Reprint requests: L. R. Kaplan, MD, University of Minnesota, Department of Medicine, Box 438 Mayo, Minneapolis, Minnesota 55455. VOLUME 25, NO. 1, 1979
13
neum (Figure 2). Occasionally, the adrenals, renal artery and vein, and the dorsal circumflex iliac arteries could be identified. From the right flank approach the posterior surface of the right kidney was easily visualized through the peritoneoscope (Figure 3A). By careful dissection of perirenal fascia in the hilar area, the renal artery, vein, and ureter
Figure 1. Lateral radiograph of pneumoretroperitoneum established in an adult dog. The endoscope in the air-filled retroperitoneum is directed toward the right kidney (R). Notice the position of the insufflation needle (arrow).
could be identified. Adequate biopsies of renal tissue were obtained under direct vision (Figure 38). The ureter was traced from the renal hilus to the bladder. The vena cava was visualized from the region of the eleventh thoracic vertebra to the third lumbar vertebra (Figure 3Q. The right adrenal could be identified by first locating the phrenicoabdominal artery and vein which lie ventral to the gland near the superior medial surface of the kidney. Visualization of the left kidney and its associated structures required a left flank approach. The aorta was identified as a pulsating structure after careful dissection in the sublumbar area anterior to the iliopsoas muscles. The vena cava, which lies to the right of the aorta, was best seen by the right flank approach. Complications. Retroperitoneal insufflation was accomplished without complication. Insertion of the needle presacrally was unassociated with bleeding, infection, or bowel perforation. Although the volume of insufflated gas in retroperitoneoscopy is 5 to 10 times that used in canine retroperitoneal pneumography,5 perineal, perianal, mediastinal, or subcutaneous emphysema did not occur. The gas which remained in the retroperitoneum after the procedure ended was rapidly absorbed. The trocar with its sharp obturator was inserted into the retroperitoneum with minimal trauma to flank muscle tissue. Six dogs observed for a minimum of 48 hours following retroperitoneoscopy and renal biopsy showed no complications. There was no evidence of infection or significant bleeding at necropsy. Renal biopsy was associated with a 10- to SO-ml blood loss. An attempted biopsy of normal adrenal tissue resulted in the only complication in the series. One animal died 6 hours after the procedure. Necropsy revealed a perforation of a renal vein.
DISCUSSION Retroperitoneoscopy in dogs is a reliable
Figure 2. Lateral radiograph of a pneumoretroperitoneum demonstrating the right (R) and left (l) kidneys, ureters (thin arrows) and aorta (thick arrows).
procedure for examining the retroperitoneal contents. The kidneys, adrenals, ureters, vena cava, and periaortic region can be easily examined. The kidney can be safely biopsied under direct vision. The similarity between the dog and human anatomy below the diaphragm suggests that retroperitoneoscopy may also have important application in the diagnosis of human retroperitoneal disease. Directed biopsy of en-
Figure 3. A, Endoscopic photograph of right kidney (thin arrows) and ureter (thick arrows) taken during retroperitoneoscopy. Clotted blood (H) from a recent renal biopsy lies on the kidney. B, Grasp biopsy of a normal dog kidney obtained under direct endoscopic vision during retroperitoneoscopy (H & E, X 66). C, Endoscopic photograph of right ureter (thin arrows) and vena cava (thick arrows) taken during retroperitoneoscopy.
14
GASTROINTESTINAL ENDOSCOPY
larged periaortic nodes or retroperitoneal masses may provide a necessary tissue diagnosis. Endoscopic renal biopsies may be indicated when a closed biopsy is associated with increased risk. Because the dog's pancreas is intraperitoneal, the value of retroperitoneoscopy in human pancreatic disease could not be studied. Cadaver studies are now underway to further evaluate the procedure. Sound patient management requires a correct diagnosis. Retroperitoneoscopy may enable the endoscopist to make a difficult diagnosis or stage malignant disease without resorting to exploratory retroperitoneal surgery.
ACkNOWLEDGMENTS The authors wish to thank Ms, Nancy Shields, RN, for assistance with the retroperitoneoscopy,
VOLUME 25, NO 1, 1979
REFERENCES 1. STEPHENS DH, WILLIAMSON B JR, SHEEDY PF, ET AL: Computerized tomography of the retroperitoneal space. Radiol Clin North Am 15:377, 1977 2, FREIMANIS AK: Echographic diagnosis of lesions of the abdominal aorta and lymph nodes. Radiol Clin North Am 13:557, 1975 3, RUlz RIUAS M: Roentgenological diagnosis: generalized subserous emphysema through a single puncture, Am / Roentgenol 64:723, 1950 4. STEINBACH Hl, SMITH DR: Extraperitoneal pneumography in diagnosis of retroperitoneal tumors, Arch Surg 70:161, 1955 5. ZESKOV B, PETROVIC B, DRAGNOVIC B: Retropneumoperitoneal visualization of abdominal organs in domestic animals. / Am Vet Rad Soc 17:23, 1976 6. BOYCE HW jR: laparoscopy, in Diseases of the Liver, L Schiff, ed. Philadelphia, IB lippincott, 1975, p, 272 7. BOYCE HW JR, PALMER ED: Techniques of Clinical Gastroenterology. Springfield, Illinois, Charles C Thomas, 1975, p. 147 8, TRUJILLO NP: Peritoneoscopy and guided biopsy in the diagnosis of intraabdominal disease, Gastroenterology 71:1083, 1976
15
