Should intra-operative manometry be routinely done in Barrett's patients?
I. Cecconello, A. Nasi, H.W. Pinotti, M.A. Oliveira (Sao Paulo)
Intraoperative esophageal manometry (IEM) was described by Cooper et al.., in 1977, as a reliable method of evaluation of Collis gastropexy and Belsey Mark IV procedure, in the prevention of gastroesophageal reflux (GER).
Hill , in 1978, intending to validate his method of treatment of GER, (which involved fixation of the lesser curvature to the arcuate ligament), reported the use of IEM, comparing values obtained with pre and postoperative conventional manometry. An important rise of lower esophageal sphincter (LES) pressure levels was registered after fundoplication, which decreased significantly in the postoperative period.
Pathological GER, as measured by ambulatory 24-hour recording, did not occur when LES was higher than 15 mmHg. Aware of this great decrease (around 50%) of LES pressure lately, he proposed an intraoperative "calibration", at the end of the esophageal wrapping, determining a pressure between 45 and 57 mmHg. According to Hill , adequate pressure levels, as measured by IEM, could provide better functional results after antireflux procedures.
Slim et al.  analyzed 30 patients who underwent fundoplication for treatment of GER. Esophageal manometry was done pre-, intra- and postoperatively, after anesthetic induction, dissection of the gastroesophageal junction and fundoplication, respectively. It was concluded that:
a) there was a similarity between LES pressure levels registered pre and intraoperatively, before esophageal dissection;
c) the first stage of fundoplication (gastric fixation to the posterior esophagus wall) determined an additional and significant increase (p < 0,02) in LES pressure;
d) at the end of procedure, a highest pressure was obtained (p < 0,05);
e) a decrease of 50 ± 19% in LES pressure was observed postoperatively, when compared to the intraoperative level.
The only recurrence of GER occurred in patient with a low intraoperative LES pressure (18,2 mmHg), which decreased later to 11,5 mmHg. They also concluded that adjustment of pressure with IEM to a level higher than 23 mmHg after fundoplication would guarantee enough contention of reflux postoperatively, even considering a decrease of 50% in the postoperative period.
As it has been discussed, some authors believe that IEM can provide parameters with good prognostic value, in terms of favorable clinical results, in this particular group. Others [4, 6] refute this observation, denying a good correlation betweeen LES intraoperative pressure and satisfactory postoperative results.
De Meester , discussing IEM, argues that LES pressure is not necessarily related with a competent antireflux barrier at the gastroesophageal junction, in patients individually studied. The main argument indicating LES pressure as an important component in prevention of GER is based on population studies in which patients with GER exhibit an average lower LES pressure, compared to controls [7, 8].
This correlation can be easily confirmed when average LES pressure levels are studied in a group of patients with reflux esophagitis. We observed in 30 cases, with and without Barrett's esophagus [9, 10], that average LES pressure was lower in the first group. Nevertheless, there was some superimposition of values between diseased patients and controls. After fundoplication and hiatoplasty, an average increase was observed with postoperative manometry. Cases with high pressure and reflux recurrence were observed, as well as competent sphincters with low pressure [9, 11].
In a recent study  analyzing 76 patients with reflux esophagitis, an hypotonic LES
(< 10 mmHg) was correlated with increasing severity of disease. It was again observed a superimposition between values in studied cases and in the control group. So, when applied to an individual case, LES pressure level does not seem an adequate method to evaluate reflux continence, invalidating intraoperative adjustment of sphincter pressure as a routine method.
It is now accepted that besides LES tonic pressure, other factors are important to avoid GER, such as the total length of intra-abdominal esophagus, as well as its functional behavior, transient relaxations being considered an important component in the genesis of reflux. Zaninotto et al.  refer some dysfunction in LES pressure in 60% of patients with GER disease, with a sphincter considered normal in the remaining cases. Bombeck et al.  consider the volume-vector of LES as the best parameter to evaluate GER contention.
Barrett's esophagus is an affection with some physiopathological differences, when compared to "typical" GERD. DeMeester et al. , studying 76 cases of Barrett's esophagus, observed some dysfunction of LES, identifiable by esophageal manometry, in 90% of them. This percentage is significantly higher than that observed in GERD without Barrett's esophagus [10, 14].
It seems valid to conclude that:
a) IEM must be considered more as a research tool, giving data on the esophagogastric junction as a barrier to GER, than as a necessary instrument in current surgical practice;
b) correlation between values obtained by IEM and technical steps in performing a fundoplication must be investigated, in order to find predictive parameters to obtain good postoperative results;
c) an attractive field of research in IEM would be the group of patients with Barrett's esophagus in which worse functional results have been observed with conventional technique , when compared to non-complicated forms of the disease.
2. Cooper JD, Gill SS, Nelems JM, Pearson FG. Intraoperative and postoperative esophageal manometric findings with Collis gastroplasty and Belsey hiatal hernia repair for gastroesophageal reflux. J Thorac Cardiovasc Surg 1977;74:744.
10. Cecconello I, Pinotti HW, Zilberstein B, Nasi A. Esofagite de refluxo. Etiopatogenic, diagnóstico e tratamento clínico. In: Pinotti HW, ed. Tratado de clínica cirúrgica do aparelho digestivo, Vol.1. Rio de Janeiro: Atheneu, 1994:354.
11. Pinotti HW, Cecconello I, Nasi A, Zilberstein B. What are the results of long term follow-up of Barrett's esophagus after surgical treatment. In: Giuli R, et al, eds. The esophageal mucosa. Amsterdam: Elsevier, 1994:939.