Video Manometry of the Sphincter of Oddi: A New Aid for Interpreting Manometric Tracings and Excluding Manometric Artefacts

• Patients and Methods
• Patients
• Methods
• Analysis
• Statistics and Ethics
• Results
• Discussion
• Conclusion
• Acknowledgements
• References

Background and Study Aims: Endoscopic sphincter of Oddi manometry (ESOM) allows direct assessment of motor function in the sphincter of Oddi. However, variations in examination conditions and duodenal motility may have a critical effect on the results of ESOM. The aim of the present study was to develop a new method - sphincter of Oddi video manometry - based on simultaneous ESOM and real-time endoscopic image analysis, and to investigate the usefulness of video manometry for detecting manometric artefacts during ESOM.

Patients and Methods: Seven consecutive patients who had undergone cholecystectomy and were referred with a suspicion of sphincter of Oddi dysfunction were investigated. Sphincter of Oddi pressure and endoscopic images (20 frames/s) were recorded simultaneously on a Synectics PC Polygraf computer system with a time-correlated basis, and then compared.

Results: On ESOM, 69 sphincter of Oddi phasic contractions were identified, with an average amplitude of 153.9 ± 85.0 mmHg and a duration of 7.9 ± 1.2 seconds. Visual analysis of the real-time endoscopic images, replayed in cine loop by the computer, revealed 236 separate duodenal contractions, with an average frequency of 3.5 ± 2.4/min (range: 1 - 12/min). On the ESOM tracing, 78 % of the duodenal contractions had a corresponding pressure wave with an average duration of 2.8 ± 0.4 seconds and an amplitude of 71.9 ± 16.7 mmHg. Other artefacts on the ESOM tracings, such as catheter movements, pseudocontractions, hyperventilation, or retching, were also easily recognized using simultaneous ESOM and real-time endoscopic image analysis.

Conclusions: Video manometry of the sphincter of Oddi is a promising new method for improving the analysis and documentation of ESOM tracings. It has several advantages over the conventional technique, allowing visual detection of duodenal activity and enabling enhanced recognition of other manometric artefacts.

Introduction

Manometry is the only diagnostic method that allows direct assessment of motor function in the sphincter of Oddi. Accurate pressure measurement in the sphincter of Oddi through the endoscope has become possible following the miniaturization of manometry catheters and the development of low-compliance fluid perfusion pressure-recording systems [1]. The sphincter of Oddi can be identified during endoscopic sphincter of Oddi manometry (ESOM) as a zone of stepwise pressure elevation (baseline pressure) relative to duodenal pressure and common bile duct pressure, with superimposed phasic contractions [2]. Sphincter of Oddi dysfunction (SOD) can be defined as abnormal sphincter of Oddi contractility, which may manifest clinically as upper right abdominal pain, or as signs and symptoms of recurrent partial biliary obstruction or pancreatitis [3]. Several manometric changes have been described in patients with SOD, such as increased baseline pressure, increased amplitude or frequency of phasic contractions, an increased number or retrograde propagation of the phasic contractions, and a paradoxical response to cholecystokinin administration [3].

Although ESOM is regarded as the gold standard for diagnosing SOD, the technique is not without problems. ESOM is a troublesome procedure for the endoscopist and also for the patient, since premedication needs to be minimized. Moreover, the difficulty of carrying out an acceptable manometric study requires close cooperation between an experienced endoscopist and a motility expert. Correct interpretation of the ESOM tracings is also often difficult [4]. ESOM has been shown to be a reproducible technique in healthy persons and in patients with sphincter of Oddi stenosis, but reproducibility has sometimes been unsatisfactory in patients with sphincter of Oddi dyskinesia [5]. One possible explanation frequently put forward is that, due to the intermittent nature of the disease, the pressure profile may differ on separate occasions. However, there are other rarely mentioned factors that may influence reproducibility. One is the possible dependence of the sphincter of Oddi pressure profile on duodenal contractions and on cyclic phases of the duodenal migrating motor complex (MMC). The other problem is the possible misinterpretation of tracings caused by the frequent artefacts, such as initial hyperactivity, catheter movement, retching, and hyperventilation [6]. Variations in the examination conditions and duodenal motility may therefore have a critical influence on the pressure profile of the sphincter of Oddi.

The aims of the present study were therefore to develop a new method - video manometry of the sphincter of Oddi - based on simultaneous manometric pressure and real-time endoscopic image analysis during the ESOM procedure; to investigate the usefulness of video manometry in detecting manometric artefacts during ESOM; and to analyze the effects of duodenal contractions on the sphincter of Oddi manometric pressure profile using video manometry.

Patients and Methods

Patients

Video manometry of the sphincter of Oddi was carried out in seven consecutive female patients who had undergone cholecystectomy (mean age 56, range 44 - 66 ) who were referred to our hospital with chronic upper right quadrant pain and a suspicion of SOD. On the Geenen classification, the patients belonged to the SOD groups for biliary types II or III, but none of them had dilation of the common bile duct. Prior to ESOM, all of the patients had normal findings on upper gastrointestinal endoscopy and abdominal ultrasonography.

Methods

After an overnight fast, sedation was induced with 2.5 - 7.5 mg intravenous midazolam (Dormicum). No other drugs were administered. Duodenoscopy was then conducted using a video duodenoscope (Olympus JF-130). For sphincter of Oddi pressure measurements, a standard triple-lumen manometric catheter was used (ERCP manometric catheter, Synectics Medical, Sweden), with an external diameter of 1.7 mm and sideholes spaced 2 mm apart. All capillary channels were constantly perfused with sterile water at a rate of 0.33 ml/min from a dual-chamber pressure pump (MUI Scientific Pump Perfusion System, Mississauga, Ontario, Canada) with 14 psi overpressure in the water reservoir. The pressures transmitted by the external transducers and the video image from the endoscope were recorded simultaneously on a Synectics PC Polygraf computer system with a time-correlated basis, using the Synectics Polygram for Windows 1.1 program.

Selective deep cannulation of the common bile duct was achieved with a standard endoscopic retrograde cholangiopancreatography (ERCP) catheter, and a flexible-tip guide wire (Wilson-Cook HSF 25/400) was then introduced high up into the bile tract. Next, the ERCP catheter was exchanged for the ESOM catheter over the guide wire, which was left in place. The duodenal pressure was recorded to establish a zero reference pressure both at the beginning and after completion of the sphincter of Oddi recording period for at least 30 seconds. After the ESOM catheter had been positioned high in the common bile duct, the guide wire was removed and the common bile duct pressure was recorded. During the station pull-through recording, the ESOM catheter was withdrawn into the sphincter of Oddi zone and retained there for a mean of nine minutes. Finally, the catheter was pushed back into the common bile duct, and a rapid pull-through over the sphincter of Oddi zone was carried out. During the ESOM study, the digital video-endoscopic monitor picture was saved continuously on the computer at a frame rate of 15 images/s. The ESOM and real-time endoscopic image analysis results were evaluated separately and then compared.

Analysis

On ESOM, the sphincter of Oddi baseline pressure and the amplitude, frequency, duration, and propagation of the phasic contractions were measured. For the sphincter of Oddi baseline calculation during the station pull-through technique, only the manometric channel located in the mid-portion of the sphincter of Oddi was used, and the average and maximum pressures were measured there as well. During real-time endoscopic image analysis, the position, duration, number, and frequency of duodenal contractions were determined, and the corresponding sequence of the ESOM recording was then carefully analyzed to search for simultaneous pressure waves. Using visual analysis, the duodenal contractions were graded as minor (small-bowel movements in the peripapillary area) or major (peristaltic movements causing complete occlusion of the duodenal lumen). If a pressure wave was found on the ESOM at the exact time of a duodenal contraction observed during real-time endoscopic image analysis, then its appearance in each individual manometric channel and its amplitude, duration, and propagation were determined. Artefacts induced on the ESOM tracings by catheter movements, hyperventilation, or retching were readily recognized using simultaneous real-time endoscopic image analysis. The occurrence of these artefacts was scored as none (0), few (1), or several (2), for each patient.

Statistics and Ethics

The unpaired Student's t-test was used for statistical evaluation, and the level of significance was set at 0.05 %. The study was approved by the local ethics committee, and it was conducted in accordance with the Helsinki Declaration. Informed consent was obtained from each patient before inclusion in the study, after verbal and written information had been provided.

Results

The average length of the simultaneous video-endoscopic and sphincter of Oddi manometric recording time was 11.5 minutes per patient. On the ESOM, 69 phasic contractions of the sphincter of Oddi were identified, with an average amplitude of 153.9 ± 85.0 mmHg and duration of 7.9 ± 1.2 seconds. The frequency of the phasic contractions ranged from 0.8/min to 3.0/min. The baseline pressure of the sphincter of Oddi was elevated (more than 35 mmHg) in two of the seven patients.

Real-time analysis of the endoscopic images was carried out by replaying the saved analogue images in cine loop on the computer without watching the pressure curve. During this process, 236 separate duodenal contractions were detected; 120 of these (51 %) were judged to be minor contractions (small duodenal movements or contractions of the peripapillary duodenal wall). The remaining 49 % were assessed as major contractions (peristaltic duodenal contraction initiating complete lumen occlusion). The average frequency of the duodenal contractions was 3.5 ± 2.4/min, with a range of 1 - 12/min.

When the real-time endoscopic image analysis results were compared with the ESOM tracing, a corresponding pressure wave was detected in 78 % of duodenal contractions on the ESOM tracing, with an average amplitude of 71.9 ± 16.7 mmHg and a duration of 2.8 ± 0.4 seconds. However, the manometric characteristics (amplitude, duration, and frequency) of the phasic contractions originating from the sphincter of Oddi and from the duodenum were significantly different (Figure [1]). A large proportion (42 %) of the 236 duodenal contractions were manifested in only one or two manometric channels, while 36 % were observed in all and 22 % in none of them. Of the 144 duodenal contractions that were clearly visible in more than one channel, allowing the virtual propagation to be determined, 37 % exhibited anterograde propagation, 49 % simultaneous propagation, and 14 % retrograde propagation on the ESOM tracing. However, the speed of this virtual propagation of the duodenal contractions was considerably slower than the propagation of the phasic contractions originating from the sphincter of Oddi (Figures [4], [6]).

Artefacts caused on the ESOM tracings by retching (Figure [2]), catheter movement-induced pseudocontractions (Figure [3]), duodenal contractions (Figure [4]), or hyperventilation (Figure [5]) were easily recognized and differentiated from real sphincter of Oddi contractions (Figure [6]) on the basis of video manometry. Retching caused a sudden, simultaneous, high and narrow pressure rise in all three channels, with an amplitude of up to 200 mmHg and a duration of less than two seconds (Figure [2]). Movements of the manometric catheter also gave rise to the phenomenon of pseudocontractions. These in-and-out movements of the catheter, due to the transmitted effect of respiration, caused pressure waves on the ESOM tracing with an amplitude and duration quite similar to those of genuine sphincter of Oddi or duodenal contractions. However, we found that these pseudocontractions were always exactly simultaneous in all channels, and they also showed a reciprocal or mirror phenomenon in channels one and three (Figure [3]). Duodenal contractions were easily distinguished from genuine sphincter of Oddi contractions by their lower amplitude, shorter duration, and slower propagation (Figure [4]). The manometric appearance of hyperventilation was quite unique, since it caused only fine undulations of the manometric curve, with an amplitude of 20 - 40 mmHg and a frequency of 16 - 20/min (Figure [5]). The availability of the real-time endoscopic images was found to be extremely useful during the ESOM analysis. With the continuous monitoring of the catheter position, it was possible to detect the site of the measurement and establish an explanation for most of the unexpected baseline undulations, which are frequently caused by catheter movements (Figure [7]). The frequencies of these artefacts were scored during the ESOM tracing analysis and then compared. The most frequent artefacts were due to duodenal contractions and catheter movements with pseudocontractions (average scores 1.8 and 1.5, respectively), followed by hyperventilation (average score 0.7) and retching (average score 0.5).

Finally, the manometric tracings were compared with and without video information on which artefacts such as duodenal contractions, retching and catheter movements had been marked. The number of events detected without video information was then calculated as a percentage of all those detected with video manometry. Eighty-seven of 236 duodenal contractions (37 %) and 34 of 40 retching episodes (85 %) were apparent without video information. With practice, 100 % of the large catheter movements (into the common bile duct and out of the sphincter of Oddi) can be recognized without video information, but small baseline undulations and pseudocontractions due to fine catheter movements (sometimes induced only by the rhythmic activity of respiration) can be explained and understood only with the aid of video manometry.

Discussion

Several manometric abnormalities have been described in patients with possible SOD. However, controlled studies in patients with postcholecystectomy pain have shown that symptomatic relief was obtained after endoscopic sphincterotomy only in patients with an elevated sphincter of Oddi baseline pressure [7], and none of the other manometric criteria for SOD have been proved to have prognostic value [3]. Although the intraobserver and interobserver reproducibility of ESOM has been found to be reasonably good [5] [8] , correct analysis of the sphincter of Oddi pressure profile can be rather difficult in any specific patient. First of all, from a manometric point of view, correct determination of the baseline pressure of a sphincter anywhere in the gastrointestinal tract may involve several problems. Some of these are related to the sphincter characteristics, such as longitudinal and transverse pressure profile asymmetry, while others relate to the manometric technique itself, such as catheter movement during the station pull-through technique and reflex sphincter contractions during the rapid pull-through technique [9]. This is particularly true for the sphincter of Oddi, which is rather short and narrow, with a marked axis deviation at the junction of the superior sphincter of the common bile duct and the inferior sphincter of the common channel [10]. We prefer the station pull-through technique to the rapid pull-through technique to measure sphincter of Oddi basal pressure, since it has the advantage of allowing precise longitudinal pressure mapping of the sphincter of Oddi, with calculation of the average and maximal basal pressure as well. However, when applying this method, it is extremely important to know the catheter position and to keep the manometric catheter in exactly the same place for a certain period of time - which is sometimes impossible, or may require small corrections to be carried out by the endoscopist. The potential offered by real-time endoscopic image analysis for monitoring the depth of insertion of the manometric catheter is therefore a genuine advantage in video manometry, allowing the basal pressure measurements to be reviewed and false pressure values to be excluded.

Secondly, there is a problem associated with duodenal activity, and this problem also has two important aspects: the possible influence of the actual stage of the interdigestive MMC on sphincter of Oddi motor activity; and the direct effect of duodenal contractions on the sphincter of Oddi pressure profile. Data from animal and human experiments have shown that phasic activity in the sphincter of Oddi is closely associated with the interdigestive phases of the MMC [11]. It has also been reported that there is a transient rise in biliary pressure in phase III (the activity front) of the duodenal MMC, probably because of the simultaneous increase in sphincter of Oddi motor activity [12]. However, the increased number of major duodenal contractions during phase III of the MMC may induce a rise in biliary pressure by passively occluding the intraduodenal segment of the sphincter of Oddi, thereby decreasing the bile outflow into the duodenum. The results of the present study support this explanation, as it was found that the duodenal contractions are not only visible on the ESOM tracing, but can also cause pressure waves with a sufficiently high amplitude and long duration to be able to influence bile outflow. The duodenal contractions that are manifested on the ESOM tracing may therefore have physiological significance, even without sphincter of Oddi motor activity.

Finally, there are well-known, troublesome, but little-discussed artefacts that make ESOM tracings difficult to analyze, and which lead to variations in reproducibility. The use of video manometry does not alter the results of ESOM if the interpretation is correct and if the manometric tracing does not contain any artefacts (Figure [8]). The method can be used to prevent false interpretation of ESOM recordings that are affected by several manometric artefacts, which are more frequently recorded in humans (Figure [9]). We believe that catheter movement is the most problematic issue, in addition to duodenal contractions, since it can make the baseline pressure unstable and can lead to the formation of pseudocontractions. With the advent of video manometry, the position of the catheter can be continuously monitored by watching the ring marks on the manometric catheter outside the papilla, and artefacts arising from the catheter movement can be excluded. In the present series, most of the artefacts occurred during periods of frequent duodenal contractile activity. We believe that these periods are not suitable for ESOM recording, and should be excluded from the final analysis.

Conclusion

Video manometry of the sphincter of Oddi is a promising and innovative method that can be used to help analyze the tracing, to exclude manometric artefacts, and to improve documentation of the tracing. It has several advantages over the conventional technique, enabling visual detection of duodenal activity and allowing a review of the depth of insertion of the manometric catheter during station pull-through measurement of sphincter of Oddi basal pressure. The use of video manometry in clinical practice may therefore be recommended. However, further studies will be needed to prove the effectiveness of the technique in improving the diagnostic accuracy and reproducibility of endoscopic sphincter of Oddi manometry.

Acknowledgements

We are grateful to Synectics Medical for supporting this study by providing the new Synectics measuring system and equipment, along with the new Synectics Polygram for Windows 1.1 manometry program. We are also grateful to the company for providing valuable technical assistance. Our thanks also go to the medical and nursing staff at Hvidovre Hospital, who made valuable contributions to the study.

References

• 1 Csendes A, Kruse A, Funch-Jensen P, et al. Pressure measurements in the biliary and pancreatic duct systems in controls and in patients with gallstones, previous cholecystectomy, or common bile duct stones.  Gastroenterology. 1979;  77 1203-1210
  PubMedSearch in Google Scholar
• 2 Geenen JE, Hogan WJ, Dodds WJ, et al. Intraluminal pressure recording from the human sphincter of Oddi.  Gastroenterology. 1980;  78 317-324
  PubMedSearch in Google Scholar
• 3 Corazziari E, Funch-Jensen P, Hogan WJ, et al. Functional disorders of the biliary tract (working team report).  Gastroenterol Int. 1993;  6 129-144
  PubMedSearch in Google Scholar
• 4 Funch-Jensen P. Defining sphincter of Oddi dysfunction.  Ther Biliary Endosc. 1996;  6 107-115
  PubMedSearch in Google Scholar
• 5 Thune A, Scicchitano J, Roberts-Thomson I, Toouli J. Reproducibility of endoscopic sphincter of Oddi manometry.  Dig Dis Sci. 1991;  36 1401-1405
  CrossrefPubMedSearch in Google Scholar
• 6 Funch-Jensen P. Sphincter of Oddi motility.  Acta Chir Scand Suppl. 1990;  553 1-35
  PubMedSearch in Google Scholar
• 7 Geenen JE, Hogan WJ, Dodds WJ, et al. The efficacy of endoscopic sphincterotomy after cholecystectomy in patients with sphincter-of-Oddi dysfunction.  N Engl J Med. 1989;  320 82-87
  PubMedSearch in Google Scholar
• 8 Smithline A, Hawes R, Lehman G. Sphincter of Oddi manometry: interobserver variability.  Gastrointest Endosc. 1993;  39 486-491
  PubMedSearch in Google Scholar
• 9 Funch-Jensen P. The clinical value of sphincter of Oddi manometry.  Gastrointest Endosc Clin N Am. 1993;  3 119-131
  PubMedSearch in Google Scholar
• 10 Teilum D. In vitro measurement of the length of the sphincter of Oddi.  Endoscopy. 1991;  23 114-116
  PubMedSearch in Google Scholar
• 11 Torsoli A, Corazziari E, Habib FI, et al. Frequencies and cyclical pattern of the human sphincter of Oddi phasic activity.  Gut. 1986;  27 363-369
  PubMedSearch in Google Scholar
• 12 Ogawa Y, Tanaka M. Biliary pressure variation in coordination with migrating motor complex of duodenum in patients with cholecystectomy and effects of morphine and caerulein.  Dig Dis Sci. 1992;  37 1531-1536
  CrossrefPubMedSearch in Google Scholar

M.D. L. Madácsy

First Dept. of Internal Medicine Albert Szent-Györgyi Medical University

Korányi fs. 8, P.O. Box 469

6725 Szeged, Hungary

Phone: +36-62-455185

Email: madl@in1st.szote.u-szeged.hu

References

• 1 Csendes A, Kruse A, Funch-Jensen P, et al. Pressure measurements in the biliary and pancreatic duct systems in controls and in patients with gallstones, previous cholecystectomy, or common bile duct stones.  Gastroenterology. 1979;  77 1203-1210
  PubMedSearch in Google Scholar
• 2 Geenen JE, Hogan WJ, Dodds WJ, et al. Intraluminal pressure recording from the human sphincter of Oddi.  Gastroenterology. 1980;  78 317-324
  PubMedSearch in Google Scholar
• 3 Corazziari E, Funch-Jensen P, Hogan WJ, et al. Functional disorders of the biliary tract (working team report).  Gastroenterol Int. 1993;  6 129-144
  PubMedSearch in Google Scholar
• 4 Funch-Jensen P. Defining sphincter of Oddi dysfunction.  Ther Biliary Endosc. 1996;  6 107-115
  PubMedSearch in Google Scholar
• 5 Thune A, Scicchitano J, Roberts-Thomson I, Toouli J. Reproducibility of endoscopic sphincter of Oddi manometry.  Dig Dis Sci. 1991;  36 1401-1405
  CrossrefPubMedSearch in Google Scholar
• 6 Funch-Jensen P. Sphincter of Oddi motility.  Acta Chir Scand Suppl. 1990;  553 1-35
  PubMedSearch in Google Scholar
• 7 Geenen JE, Hogan WJ, Dodds WJ, et al. The efficacy of endoscopic sphincterotomy after cholecystectomy in patients with sphincter-of-Oddi dysfunction.  N Engl J Med. 1989;  320 82-87
  PubMedSearch in Google Scholar
• 8 Smithline A, Hawes R, Lehman G. Sphincter of Oddi manometry: interobserver variability.  Gastrointest Endosc. 1993;  39 486-491
  PubMedSearch in Google Scholar
• 9 Funch-Jensen P. The clinical value of sphincter of Oddi manometry.  Gastrointest Endosc Clin N Am. 1993;  3 119-131
  PubMedSearch in Google Scholar
• 10 Teilum D. In vitro measurement of the length of the sphincter of Oddi.  Endoscopy. 1991;  23 114-116
  PubMedSearch in Google Scholar
• 11 Torsoli A, Corazziari E, Habib FI, et al. Frequencies and cyclical pattern of the human sphincter of Oddi phasic activity.  Gut. 1986;  27 363-369
  PubMedSearch in Google Scholar
• 12 Ogawa Y, Tanaka M. Biliary pressure variation in coordination with migrating motor complex of duodenum in patients with cholecystectomy and effects of morphine and caerulein.  Dig Dis Sci. 1992;  37 1531-1536
  CrossrefPubMedSearch in Google Scholar

M.D. L. Madácsy

First Dept. of Internal Medicine Albert Szent-Györgyi Medical University

Korányi fs. 8, P.O. Box 469

6725 Szeged, Hungary

Phone: +36-62-455185

Email: madl@in1st.szote.u-szeged.hu