International Journal ofPancreatology, vol. 12, no. 3:233-237. December 1992 9 Copyright 1992 by The Humana Press Inc. All rights of any nature whatsoever reserved.
0169-4197192112/3:233-237I$2.00
Intraoperative Ultrasonography in Surgery for Chronic Pancreatitis Hartmut Printz, ~1 Hans-Jiirg Klotter, 1 Christoph N i e s / Christian Hasse, ~Markus Neurath, ~ Helmut Sitter, 2 and Mattias R o t h m u n d ~ ~Department of Surgery, PhiIipps-University of Marburg; and Vnstitute of Theoretical Surgery, Philipps-University of Marburg, W-3550 Marburg, Germany
Summary We report our experience with intraoperative ultrasonography in 49 patients undergoing surgery for chronic pancreatitis. Among drainage procedures, there were 14 laterolateral pancreaticojejunostomies, 15 pseudocystojejunostomies, and 2 pseudocystoduodenostomies. Under the guidance of intraoperative ultrasonography, left sided partial resection of the pancreas was performed in 7 patients, whereas a Whipple-type procedure wasnecessary in 6 cases. All preoperatively diagnosed pseudocysts, abscess formations, and dilated pancreatic ductal systems could be easily localized with the assistance of intraoperative ultrasound. Additionally to diagnoses already made preoperatively, intraoperative ultrasonography revealed a second, smaller pseudocyst in one patient and pancreaticolithiasis in another case~ However, significant assistance and comfort to the operating surgeon was provided in all cases by intraoperative ultrasound imaging. This technique, which is cost effective and minimally invasive, proved to be extremely helpful in localizing pancreatic fluid collections and the course of the pancreatic duct. It facilitates the operation by reducing tissue traumatization and operative time. In experienced hands, intraoperative ultrasonography is a reliable method and a useful adjunct to the surgeon. Key Words: Intraoperative ultrasound; pancreatic duct; pseudocyst; abscess; pancreatic surgery. Morphologically fibrosis, frequent occurrence of ductal strictures and dilatations, as well as intraductal protein plugs and calcified precipitates are frequently found (1). The majority of patients with chronic pancreatitis can be managed conservatively, but indications for surgical interventions are intractable abdominal pain and complications, such as pseudocysts, abcesses, and pancreatic duct obstructions (2,3). The common surgical approaches to the management of chronic pancreatitis are either direct drainage by pseudocystoenterostomy and pancreaticojejunostomy or resection o f the most severely affected part of the gland (2). Further surgical procedures, which may be necessary in patients with chronic pancreatitis, but are not dealt with in this
Introduction Chronic pancreatitis is defined as continuing inflammatory disease o f the pancreas, characterized by irreversible morphological changes that may lead to a progressive loss of exocrine and endocrine function. Recurrent or persisting abdominal pain is a major symptom, although chronic pancreatitis may be present without pain (1). Received March 30, 1992; Revised April 20, 1992; Accepted May 4, 1992 *Author to whom correspondence and reprint requests should be addressed: Zentrum Operative Medizin I, PhilippsUniversitat Marburg, Baldingerstrasse, W-3550 Marburg/Lahn, Germany
International Journal of Pancrearology
233
Volume 12, 1992
234 communication, are biliary and gastrointestinal bypass operations owing to common bile duct stenosis or duodenal obstruction, respectively (2). Progress in ultrasonographic instrumentation has expanded the application of intraoperative ultrasonography (IOUS). The use of IOUS is gaining popularry, particularly as a technical aid in pancreatic surgery (3-8). Intraoperative localization of the dilated pancreatic duct for laterolateral pancreaticojejunostomy within the hard, inflamed, and fibrotic pancreas with scattered calcifications merely by bimanual palpation and needle puncture, is a difficult and time-consuming task (3). It frequently leads to unnecessary tissue damage and added risk of complication. Furthermore, small pseudocysts and intrapancreatic fluid collections may also be nonpalpable and invisible during surgery. In this article we review our experience with IOUS during surgery for chronic pancreatitis.
Material and Methods With the assistance of intraoperative ultrasonography 49 patients underwent surgery for chronic pancreatitis at our institution between May 1987 and December 1991o There were 34 male and 15 female patients with a mean age of 43 + 2 years. After full operative exposure and completion of pancreatic surface inspection as well as bimanual palpation, IOUS was performed utilizing a commercially available, standard ultrasound unit (Siemens Sonoline AC). For scanning an electronic, high-resolution, 5.0 MHz linear scanner and a small part 7.5 MHz linear transducer in T-shaped configuration with a long coaxial cable were utilized (Fig. 1). The probes were either cold-gas sterilized or inserted into a long sterile, disposable plastic sleeve containing methylcellulose gel at the distal tip. Warm saline was put into the operative field and the scan head submerged in order to provide additional acoustic coupling. Using the probe standoff technique, the applicator was maneuvered in a distance of 0.5-1.5 cm from the tissue surface and the pancreas was scanned systematically by the surgeon himself. The examination of the pancreas was carried out with longitudinal scans from the pancreatic head across the body to the tail
International Journal of Pancreatology
Printz et al. visualizing the pancreas in sagittal imaging planes. Several parallel passes were necessary for complete examination of the whole gland. Then, a series of craniocaudal scans (transverse imaging planes) followed after a 90 ~ rotation of the transducer. The splenic vein, superior mesenteric vein, portal vein, inferior vena cava, abdominal aorta, hepatic artery, as well as the common bile duct served as important anatomic landmarks for orientation. Real-time sonograms were twodimensional (B-mode) and could be recorded by Polaroid photography. For intraoperative localization and dissection of the main pancreatic duct in order to perform longitudinal side-to-side pancreaticojejunostomy, the pancreatic duct was visualized first in a longitudinal imaging plane to select the ductal segment with the greatest dilation and the most appropriate site of entry into the ductal system. We first located the duct in the body of the pancreas. Then we demonstrated its course into the head and tail. Right above the appropriate point of entry into the pancreatic duct, the transducer was rotated by 90 ~. By manually depressing the anterior surface of the gland the relation of the pancreatic duct to the scanning head was determined and the pancreatic duct was punctured with a needle (0.55 x 25.0 ram) at the appropriate point. The movement of the white reflex on the television monitor--mirroring the tip of the needle--into the pancreatic duct, as well as the appearance of white opaque fluid aspirated through the needle indicated successful puncturing. Preoperative information about intraductal calculi and pancreatic duct obstruction, obtained by ultrasound, computed tomography, and endoscopic retrograde cholangiopancreatography, was confirmed by IOUS. During incision of the pancreatic parenchyma, scanning could be repeated whenever necessary. Full pancreas mobilization facilitated the scanning maneuver because the probe could be placed easily at any position. In patients undergoing internal pseudoeyst drainage, most frequently into a defunctionalized Roux-en-Y loop of jejunum, IOUS was used after exploration by inspection and palpation to localize the pseudocyst(s) in its total size and extension. Cyst wall thickness, nearby structures that should not be injured during the procedure, and potential septa were determined. Employing IOUS
Volume 12, 1992
Ultrasound During Pancreatic Surgery
235
Fig. 1. High resolution, 5.0 MHz linear scanner (left) and the T-shaped 7.5 MHz transducer (right) used for IOUS. the most appropriate drainage site of the pseudocyst for anastomosis with the small bowel--preferably at the most caudal point--was determined. In all patients the pancreas was carefully scanned for associated abnormalities besides the main pathologic feature. Those associated conditions were usually related with pancreatitis, such as additional or previously unknown pseudocysts or an unsuspectedly dilated ductal system. In addition, IOUS was helpful for guiding operative procedures when pancreatic resections were carried out. When indicated, ultrasound-guided needle placement for aspiration biopsy of suspect lesions was performed avoiding blood vessel and pancreatic duct injury. Direction and depth of needle insertion were controlled by observing the tip of the needle and the target lesion on the television monitor. For aspiration biopsy, the needle was inserted into the mass and moved up and down several times while applying suction. The imaging procedure added an average of about 15 minutes to the operation time.
Results Utilizing IOUS, we performed 49 operations for chronic pancreatitis and its complications. Among drainage procedures there were laterolateral pan-
International Journal of Pancreatology
creaticojejunostoInies in 14 patients, pseudocystojejunostomies in 15 patients, and pseudocystoduodenostomies in 2 cases. Left sided partial resection of the pancreas under the guidance of IOUS was performed in 7 patients, while--after intraoperative ultrasound scanning of the pancreas--a Whippletype pancreatoduodenectomy was necessary in 6 patients. Five patients underwent surgical drainage of pancreatic abscess formations, caused by chronic pancreatitis. In all patients the anatomic landmarks adjacent to the pancreas and the main pancreatic duct could be precisely localized by IOUS. Normal pancreata produced uniform, bright echo patterns with smooth contours, but the echomorphologic pattern of the chronically inflamed pancreas was coarse, hyperechoic, and more intense. Pancreatic size in chronic pancreatitis was variable. The borders of the normal pancreata could be exactly defined in all control subjects, but the contour of the chronically inflamed pancreas was irregular and poorly defined in many cases, owing to increased echogeneity of the pancreas. The latter produced a texture similar to that of the surrounding retropefitoneai fat. The pancreatic duct was seen within the pancreas ventral to the splenic vein as a transversely oriented, normally hypoechoic tube lined by parallel hyperechoic walls~ Normal Wirsung ducts of
Volume 12, 1992
236 control subjects had an inner diameter measured in the body of the pancreas smaller than 2.0 mm with smooth walls. In 14 patients subjected to laterolateral pancreaticojejunostomy with a Roux-en-Y loop of jejunum, dilation of the main pancreatic duct was detected intraoperatively by IOUS, caused by intraductal precipitates and/or duct strictures. The diameter of the dilated duct al segments ranged from 4 to 15 ram, with a mean of 8 ram. From preoperative imaging studies these duct dilatations were already known in all cases. However, without the assistance of IOUS, the intraoperative localization of the irregularly dilated pancreatic ducts would have been much more difficult and time consuming. Multiple calculi were demonstrated sonographically within 8 of the 14 dilated ducts. Preoperative imaging studies had revealed pancreatic lithiasis in 7 of those 8 patients~ Intraductal stones diagnosed by IOUS were surgically confirmed in all cases. Pancreatic calcifications were recognized sonographically as small, highly reflective particles that gave the gland a stippled appearance. Stones lying free in a dilated duct were distinguishable from parenchyma calcifications by the surrounding echofree tubular structure that represented the Wirsung duct (Fig. 2). Acoustic shadowing behind the stones was sometimes present (Fig. 2). Stone removal was achieved after incision and unroofing of the IOUS-localized pancreatic duct using either a Fogarty balloon catheter or surgical forceps toward the head and the tail of the pancreas. Using IOUS, which could be applied whenever necessary during calculi extraction procedures, control of complete stone removal was possible. After calculi extraction longitudinal side-to-side pancreaticojejunostomy was performed using a Roux-en-Y limb of jejenum. All preoperatively d i a g n o s e d pseudocysts, abscess formations, and dilated pancreatic ductal systems could be localized intraoperatively with ease under the help of IOUS. Internal pseudcystdrainage into the duodenum was performed in two cases because of one or two pseudocyst formations in the head of the pancreas, respectively. All those three pseudocysts were already known by preoper-
International Journal of Pancreatology
Printz et al. ative imaging procedures. A total of 20 pseudocysts were detected among the 15 patients undergoing pseudocyst drainage into the jejunum. In one case-besides a large pseudocyst diagnosed already preoperatively and giving indication for surgery--one additional, smaller, so far unknown pseudocyst was found by IOUS. The average pseudocyst wall thickness was 2-4 rnm. Although only in one case a small pseudocyst and in a second patient so far unknown pancreaticolithiasis must be mentioned as additional information provided by IOUS, this technique gave significant assistance and comfort to the operating surgeon in all cases. In patients undergoing surgical abscess drainage localization maneuvers as welt as detection of abscess size and extension was easily possible. In 14 cases IOUS-guided aspiration biopsies of suspect areas were necessary intraoperatively.
Discussion Usually the diagnosis of complications of chronic pancreatitis can be made preoperatively by physical examination, external abdominal sonography, angiogram enhanced computed tomography, and endoscopic retrograde cholangiopancreatography. It is confirmed by intraoperative exploration. IOUS provides significant help in intraoperative localization of pancreatic abscess formations with all its extension, potential septa, and remote pockets (3,8). Also IOUS is helpful in defining pseudocysts, especially if they are small or located deeply (8). Furthermore surrounding anatomic structures are quickly identified with safety (3,4). More than one area of pancreatic enlargement or tissue swelling may be discovered at exploration, IOUS helps the surgeon to determine which area harbors a pseudocyst or an abscess and which is merely tissue swelling that should be left alone (7,8). IOUS is particularly valuable in guiding the needle for safe biopsy of suspect lesions. Because the intraoperative scanning of the pancreas usually requires only penetration depths of 4-6 cm, it is possible to use ultrasound scanners that operate at high frequencies. Since the higher the frequency, the better the resolution but the lower the depth of penetration, detailed intraoperative images of the pancreas are obtained (8). Inter-
Volume 12, 1992
Ultrasound During Pancreatic Surgery
237
Fig. 2. Hyperechogenic pancreatic duct calculus with slight dorsal shadowing detected within the dilated Wirsung duct in a patient with chronic calcifying pancreatitis. nal anatomy is better defined by intraoperative than by transcutaneous abdominal ultrasound, especially in patients with considerable bowel gas or extensive adipose tissue, which may significantly degrade the preoperative ultrasound examination. According to SIGEL the use of IOUS during pancreatic surgery for inflammatory disease can help the surgeon in several principal ways (3,8). First, the procedure can facilitate the operation by reducing tissue traumatization and operative time. Second, IOUS helps to avoid injury to structures that should be protected during the procedure. Third, IOUS assists to assure the surgeon that associated abnormalities, which are undiagnosed either on preoperative studies or on exploration, are not being missed (3). In conclusion, IOUS is a useful adjunct to surgical inspection and palpation for diagnosing and defining pancreatic pseudocysts, abscesses, and dilated pancreatic ducts. IOUS is a rapid, safe, and cost-effective technique. It is minimally invasive and it can image previously occult lesions. Although ultrasound is observerdependent and it takes time and effort to get familiar with the technique, with proper training and equipment it can be easily performed and interpreted at the operating table by the surgeon him- or herself.
International Journal of Pancreatology
References 1 Sarles H, Adler G, Dani R, Frey C, Gulla L, Harada H, Martin E, Norohna M, Scuro, LA. Classification of pancreatitis and definition of pancreatic disease. Digestion 1989; 43: 234-236. 2 Rothmund M. Chronische Pancreatitis. In: Chirurgische Operationslehre. Kremer K, Lierse W, Platzer W, Schreiber HW, Weller S., eds., Georg Thieme Verlag Stuttgart, New York, 1990, pp. 155-175. 3 Sigel B, Machi J, Kikuchi T, Anderson lII, KW, Horrow M, Zaren HA. The use of ultrasound during surgery for complications of pancreatitis. World J Surg 1987; 1 l: 659663. 4 Klotter HJ, Kuhn FP, Rtickert K, Neher M, Hinkel E, Kflmmerle F. Intraoperative Ultraschalluntersuchungen bei Pankreaseingriffen. Dtsch med Wschr 1983; 108: 14631468. 5 Klotter HJ, Rackert tC Mentges B, Grtissner R, Schild H. Intraoperative Ultraschalluntersuchung in der Chirurgie. Ultraschall 1986; 7: 224-230. 6 Klotter H J, Rtickert K, Ktimmerle F, Rothmund M. The u s e of intraoperative sonography in endocrine tumors of the pancreas. World J Surg 1987; 11: 635-641. 9 Sigel B, Coelho JCU, Donahue PE, Nyhus LM, Spigos 13(3, Baker RJ, Machi J. Ultrasonic assistance during surgery for pancreatic inflammatory disease. Arch Surg 1982; 117: 712-716. 8 Sigel B, Machi J, Kikuchi T, et al. Intraoperative ultrasound of the liver and pancreas. Adv Surg 1987; 21: 213-244.
Volume 12, 1992
0169-4197192112/3:233-237I$2.00
Intraoperative Ultrasonography in Surgery for Chronic Pancreatitis Hartmut Printz, ~1 Hans-Jiirg Klotter, 1 Christoph N i e s / Christian Hasse, ~Markus Neurath, ~ Helmut Sitter, 2 and Mattias R o t h m u n d ~ ~Department of Surgery, PhiIipps-University of Marburg; and Vnstitute of Theoretical Surgery, Philipps-University of Marburg, W-3550 Marburg, Germany
Summary We report our experience with intraoperative ultrasonography in 49 patients undergoing surgery for chronic pancreatitis. Among drainage procedures, there were 14 laterolateral pancreaticojejunostomies, 15 pseudocystojejunostomies, and 2 pseudocystoduodenostomies. Under the guidance of intraoperative ultrasonography, left sided partial resection of the pancreas was performed in 7 patients, whereas a Whipple-type procedure wasnecessary in 6 cases. All preoperatively diagnosed pseudocysts, abscess formations, and dilated pancreatic ductal systems could be easily localized with the assistance of intraoperative ultrasound. Additionally to diagnoses already made preoperatively, intraoperative ultrasonography revealed a second, smaller pseudocyst in one patient and pancreaticolithiasis in another case~ However, significant assistance and comfort to the operating surgeon was provided in all cases by intraoperative ultrasound imaging. This technique, which is cost effective and minimally invasive, proved to be extremely helpful in localizing pancreatic fluid collections and the course of the pancreatic duct. It facilitates the operation by reducing tissue traumatization and operative time. In experienced hands, intraoperative ultrasonography is a reliable method and a useful adjunct to the surgeon. Key Words: Intraoperative ultrasound; pancreatic duct; pseudocyst; abscess; pancreatic surgery. Morphologically fibrosis, frequent occurrence of ductal strictures and dilatations, as well as intraductal protein plugs and calcified precipitates are frequently found (1). The majority of patients with chronic pancreatitis can be managed conservatively, but indications for surgical interventions are intractable abdominal pain and complications, such as pseudocysts, abcesses, and pancreatic duct obstructions (2,3). The common surgical approaches to the management of chronic pancreatitis are either direct drainage by pseudocystoenterostomy and pancreaticojejunostomy or resection o f the most severely affected part of the gland (2). Further surgical procedures, which may be necessary in patients with chronic pancreatitis, but are not dealt with in this
Introduction Chronic pancreatitis is defined as continuing inflammatory disease o f the pancreas, characterized by irreversible morphological changes that may lead to a progressive loss of exocrine and endocrine function. Recurrent or persisting abdominal pain is a major symptom, although chronic pancreatitis may be present without pain (1). Received March 30, 1992; Revised April 20, 1992; Accepted May 4, 1992 *Author to whom correspondence and reprint requests should be addressed: Zentrum Operative Medizin I, PhilippsUniversitat Marburg, Baldingerstrasse, W-3550 Marburg/Lahn, Germany
International Journal of Pancrearology
233
Volume 12, 1992
234 communication, are biliary and gastrointestinal bypass operations owing to common bile duct stenosis or duodenal obstruction, respectively (2). Progress in ultrasonographic instrumentation has expanded the application of intraoperative ultrasonography (IOUS). The use of IOUS is gaining popularry, particularly as a technical aid in pancreatic surgery (3-8). Intraoperative localization of the dilated pancreatic duct for laterolateral pancreaticojejunostomy within the hard, inflamed, and fibrotic pancreas with scattered calcifications merely by bimanual palpation and needle puncture, is a difficult and time-consuming task (3). It frequently leads to unnecessary tissue damage and added risk of complication. Furthermore, small pseudocysts and intrapancreatic fluid collections may also be nonpalpable and invisible during surgery. In this article we review our experience with IOUS during surgery for chronic pancreatitis.
Material and Methods With the assistance of intraoperative ultrasonography 49 patients underwent surgery for chronic pancreatitis at our institution between May 1987 and December 1991o There were 34 male and 15 female patients with a mean age of 43 + 2 years. After full operative exposure and completion of pancreatic surface inspection as well as bimanual palpation, IOUS was performed utilizing a commercially available, standard ultrasound unit (Siemens Sonoline AC). For scanning an electronic, high-resolution, 5.0 MHz linear scanner and a small part 7.5 MHz linear transducer in T-shaped configuration with a long coaxial cable were utilized (Fig. 1). The probes were either cold-gas sterilized or inserted into a long sterile, disposable plastic sleeve containing methylcellulose gel at the distal tip. Warm saline was put into the operative field and the scan head submerged in order to provide additional acoustic coupling. Using the probe standoff technique, the applicator was maneuvered in a distance of 0.5-1.5 cm from the tissue surface and the pancreas was scanned systematically by the surgeon himself. The examination of the pancreas was carried out with longitudinal scans from the pancreatic head across the body to the tail
International Journal of Pancreatology
Printz et al. visualizing the pancreas in sagittal imaging planes. Several parallel passes were necessary for complete examination of the whole gland. Then, a series of craniocaudal scans (transverse imaging planes) followed after a 90 ~ rotation of the transducer. The splenic vein, superior mesenteric vein, portal vein, inferior vena cava, abdominal aorta, hepatic artery, as well as the common bile duct served as important anatomic landmarks for orientation. Real-time sonograms were twodimensional (B-mode) and could be recorded by Polaroid photography. For intraoperative localization and dissection of the main pancreatic duct in order to perform longitudinal side-to-side pancreaticojejunostomy, the pancreatic duct was visualized first in a longitudinal imaging plane to select the ductal segment with the greatest dilation and the most appropriate site of entry into the ductal system. We first located the duct in the body of the pancreas. Then we demonstrated its course into the head and tail. Right above the appropriate point of entry into the pancreatic duct, the transducer was rotated by 90 ~. By manually depressing the anterior surface of the gland the relation of the pancreatic duct to the scanning head was determined and the pancreatic duct was punctured with a needle (0.55 x 25.0 ram) at the appropriate point. The movement of the white reflex on the television monitor--mirroring the tip of the needle--into the pancreatic duct, as well as the appearance of white opaque fluid aspirated through the needle indicated successful puncturing. Preoperative information about intraductal calculi and pancreatic duct obstruction, obtained by ultrasound, computed tomography, and endoscopic retrograde cholangiopancreatography, was confirmed by IOUS. During incision of the pancreatic parenchyma, scanning could be repeated whenever necessary. Full pancreas mobilization facilitated the scanning maneuver because the probe could be placed easily at any position. In patients undergoing internal pseudoeyst drainage, most frequently into a defunctionalized Roux-en-Y loop of jejunum, IOUS was used after exploration by inspection and palpation to localize the pseudocyst(s) in its total size and extension. Cyst wall thickness, nearby structures that should not be injured during the procedure, and potential septa were determined. Employing IOUS
Volume 12, 1992
Ultrasound During Pancreatic Surgery
235
Fig. 1. High resolution, 5.0 MHz linear scanner (left) and the T-shaped 7.5 MHz transducer (right) used for IOUS. the most appropriate drainage site of the pseudocyst for anastomosis with the small bowel--preferably at the most caudal point--was determined. In all patients the pancreas was carefully scanned for associated abnormalities besides the main pathologic feature. Those associated conditions were usually related with pancreatitis, such as additional or previously unknown pseudocysts or an unsuspectedly dilated ductal system. In addition, IOUS was helpful for guiding operative procedures when pancreatic resections were carried out. When indicated, ultrasound-guided needle placement for aspiration biopsy of suspect lesions was performed avoiding blood vessel and pancreatic duct injury. Direction and depth of needle insertion were controlled by observing the tip of the needle and the target lesion on the television monitor. For aspiration biopsy, the needle was inserted into the mass and moved up and down several times while applying suction. The imaging procedure added an average of about 15 minutes to the operation time.
Results Utilizing IOUS, we performed 49 operations for chronic pancreatitis and its complications. Among drainage procedures there were laterolateral pan-
International Journal of Pancreatology
creaticojejunostoInies in 14 patients, pseudocystojejunostomies in 15 patients, and pseudocystoduodenostomies in 2 cases. Left sided partial resection of the pancreas under the guidance of IOUS was performed in 7 patients, while--after intraoperative ultrasound scanning of the pancreas--a Whippletype pancreatoduodenectomy was necessary in 6 patients. Five patients underwent surgical drainage of pancreatic abscess formations, caused by chronic pancreatitis. In all patients the anatomic landmarks adjacent to the pancreas and the main pancreatic duct could be precisely localized by IOUS. Normal pancreata produced uniform, bright echo patterns with smooth contours, but the echomorphologic pattern of the chronically inflamed pancreas was coarse, hyperechoic, and more intense. Pancreatic size in chronic pancreatitis was variable. The borders of the normal pancreata could be exactly defined in all control subjects, but the contour of the chronically inflamed pancreas was irregular and poorly defined in many cases, owing to increased echogeneity of the pancreas. The latter produced a texture similar to that of the surrounding retropefitoneai fat. The pancreatic duct was seen within the pancreas ventral to the splenic vein as a transversely oriented, normally hypoechoic tube lined by parallel hyperechoic walls~ Normal Wirsung ducts of
Volume 12, 1992
236 control subjects had an inner diameter measured in the body of the pancreas smaller than 2.0 mm with smooth walls. In 14 patients subjected to laterolateral pancreaticojejunostomy with a Roux-en-Y loop of jejunum, dilation of the main pancreatic duct was detected intraoperatively by IOUS, caused by intraductal precipitates and/or duct strictures. The diameter of the dilated duct al segments ranged from 4 to 15 ram, with a mean of 8 ram. From preoperative imaging studies these duct dilatations were already known in all cases. However, without the assistance of IOUS, the intraoperative localization of the irregularly dilated pancreatic ducts would have been much more difficult and time consuming. Multiple calculi were demonstrated sonographically within 8 of the 14 dilated ducts. Preoperative imaging studies had revealed pancreatic lithiasis in 7 of those 8 patients~ Intraductal stones diagnosed by IOUS were surgically confirmed in all cases. Pancreatic calcifications were recognized sonographically as small, highly reflective particles that gave the gland a stippled appearance. Stones lying free in a dilated duct were distinguishable from parenchyma calcifications by the surrounding echofree tubular structure that represented the Wirsung duct (Fig. 2). Acoustic shadowing behind the stones was sometimes present (Fig. 2). Stone removal was achieved after incision and unroofing of the IOUS-localized pancreatic duct using either a Fogarty balloon catheter or surgical forceps toward the head and the tail of the pancreas. Using IOUS, which could be applied whenever necessary during calculi extraction procedures, control of complete stone removal was possible. After calculi extraction longitudinal side-to-side pancreaticojejunostomy was performed using a Roux-en-Y limb of jejenum. All preoperatively d i a g n o s e d pseudocysts, abscess formations, and dilated pancreatic ductal systems could be localized intraoperatively with ease under the help of IOUS. Internal pseudcystdrainage into the duodenum was performed in two cases because of one or two pseudocyst formations in the head of the pancreas, respectively. All those three pseudocysts were already known by preoper-
International Journal of Pancreatology
Printz et al. ative imaging procedures. A total of 20 pseudocysts were detected among the 15 patients undergoing pseudocyst drainage into the jejunum. In one case-besides a large pseudocyst diagnosed already preoperatively and giving indication for surgery--one additional, smaller, so far unknown pseudocyst was found by IOUS. The average pseudocyst wall thickness was 2-4 rnm. Although only in one case a small pseudocyst and in a second patient so far unknown pancreaticolithiasis must be mentioned as additional information provided by IOUS, this technique gave significant assistance and comfort to the operating surgeon in all cases. In patients undergoing surgical abscess drainage localization maneuvers as welt as detection of abscess size and extension was easily possible. In 14 cases IOUS-guided aspiration biopsies of suspect areas were necessary intraoperatively.
Discussion Usually the diagnosis of complications of chronic pancreatitis can be made preoperatively by physical examination, external abdominal sonography, angiogram enhanced computed tomography, and endoscopic retrograde cholangiopancreatography. It is confirmed by intraoperative exploration. IOUS provides significant help in intraoperative localization of pancreatic abscess formations with all its extension, potential septa, and remote pockets (3,8). Also IOUS is helpful in defining pseudocysts, especially if they are small or located deeply (8). Furthermore surrounding anatomic structures are quickly identified with safety (3,4). More than one area of pancreatic enlargement or tissue swelling may be discovered at exploration, IOUS helps the surgeon to determine which area harbors a pseudocyst or an abscess and which is merely tissue swelling that should be left alone (7,8). IOUS is particularly valuable in guiding the needle for safe biopsy of suspect lesions. Because the intraoperative scanning of the pancreas usually requires only penetration depths of 4-6 cm, it is possible to use ultrasound scanners that operate at high frequencies. Since the higher the frequency, the better the resolution but the lower the depth of penetration, detailed intraoperative images of the pancreas are obtained (8). Inter-
Volume 12, 1992
Ultrasound During Pancreatic Surgery
237
Fig. 2. Hyperechogenic pancreatic duct calculus with slight dorsal shadowing detected within the dilated Wirsung duct in a patient with chronic calcifying pancreatitis. nal anatomy is better defined by intraoperative than by transcutaneous abdominal ultrasound, especially in patients with considerable bowel gas or extensive adipose tissue, which may significantly degrade the preoperative ultrasound examination. According to SIGEL the use of IOUS during pancreatic surgery for inflammatory disease can help the surgeon in several principal ways (3,8). First, the procedure can facilitate the operation by reducing tissue traumatization and operative time. Second, IOUS helps to avoid injury to structures that should be protected during the procedure. Third, IOUS assists to assure the surgeon that associated abnormalities, which are undiagnosed either on preoperative studies or on exploration, are not being missed (3). In conclusion, IOUS is a useful adjunct to surgical inspection and palpation for diagnosing and defining pancreatic pseudocysts, abscesses, and dilated pancreatic ducts. IOUS is a rapid, safe, and cost-effective technique. It is minimally invasive and it can image previously occult lesions. Although ultrasound is observerdependent and it takes time and effort to get familiar with the technique, with proper training and equipment it can be easily performed and interpreted at the operating table by the surgeon him- or herself.
International Journal of Pancreatology
References 1 Sarles H, Adler G, Dani R, Frey C, Gulla L, Harada H, Martin E, Norohna M, Scuro, LA. Classification of pancreatitis and definition of pancreatic disease. Digestion 1989; 43: 234-236. 2 Rothmund M. Chronische Pancreatitis. In: Chirurgische Operationslehre. Kremer K, Lierse W, Platzer W, Schreiber HW, Weller S., eds., Georg Thieme Verlag Stuttgart, New York, 1990, pp. 155-175. 3 Sigel B, Machi J, Kikuchi T, Anderson lII, KW, Horrow M, Zaren HA. The use of ultrasound during surgery for complications of pancreatitis. World J Surg 1987; 1 l: 659663. 4 Klotter HJ, Kuhn FP, Rtickert K, Neher M, Hinkel E, Kflmmerle F. Intraoperative Ultraschalluntersuchungen bei Pankreaseingriffen. Dtsch med Wschr 1983; 108: 14631468. 5 Klotter HJ, Rackert tC Mentges B, Grtissner R, Schild H. Intraoperative Ultraschalluntersuchung in der Chirurgie. Ultraschall 1986; 7: 224-230. 6 Klotter H J, Rtickert K, Ktimmerle F, Rothmund M. The u s e of intraoperative sonography in endocrine tumors of the pancreas. World J Surg 1987; 11: 635-641. 9 Sigel B, Coelho JCU, Donahue PE, Nyhus LM, Spigos 13(3, Baker RJ, Machi J. Ultrasonic assistance during surgery for pancreatic inflammatory disease. Arch Surg 1982; 117: 712-716. 8 Sigel B, Machi J, Kikuchi T, et al. Intraoperative ultrasound of the liver and pancreas. Adv Surg 1987; 21: 213-244.
Volume 12, 1992
