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THE EFFECT OF FUNDOPLICATION ON THE MOTILITY OF THE CANINE LOWER OESOPHAGEAL SPHINCTER
Author(s) -
Cox Michael R.,
Franzi Stephen J.,
Martin Christopher J.
Publication year - 2000
Publication title -
australian and new zealand journal of surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.111
H-Index - 51
eISSN - 1445-2197
pISSN - 0004-8682
DOI - 10.1046/j.1440-1622.2000.01747.x
Subject(s) - medicine , reflux , myotomy , swallowing , esophagogastric junction , nissen fundoplication , anesthesia , insufflation , esophagus , surgery , gastroenterology , achalasia , adenocarcinoma , disease , cancer
Background : A canine model was used to define whether Nissen fundoplication inhibits gastro‐oesophageal reflux by inhibiting transient lower oesophageal sphincter relaxations (TLOSR) or by creating a pressure barrier at the gastro‐oesophageal junction. Methods : Four surgical models were studied pre‐operatively and postoperatively. These were: (i) the surgical mobilization required for fundoplication (sham fundoplication, n = 5); (ii) a standard fundoplication ( n = 4); (iii) anterior and posterior myotomy of the lower oesophageal sphincter (LOS; cardiomyotomy, n = 4); and (iv) combined cardiomyotomy and fundoplication ( n = 4). Each operative procedure was assessed for its effect on the incidence of TLOSR and gas reflux events, the mean LOS pressure and the LOS pressure profile during swallow events. Results : Sham fundoplication reduced the rate of evoked TLOSR in response to gaseous gastric insufflation from 9.8 ± 1.6/h (mean ± SΕΜ) to 5.4 ± 1.5/h. The mean LOS pressure was reduced from 25.1 ± 2.6 to 18.5 ± 2.1 mmHg but nadir LOS pressure during swallowing was not altered. Nissen fundoplication virtually abolished evoked TLOSR from 10.4 ± 1.2/h to 0.4 ± 0.4/h, increased mean basal LOS pressure from 19.8 ± 2.1 to 27.0 ± 1.1 mmHg and increased the nadir pressure on swallowing from 3.4 ± 1.0 mmHg to 14.4 ± 1.0 mmHg. Cardiomyotomy was associated with a near continuous leakage of gas across a chronically hypotensive LOS. Cardiomyotomy reduced the resting LOS pressure from 14.7 ± 1.2 mmHg to 2.3 ± 1.0 mmHg. Cardiomyotomy with fundoplication was associated with no loss of LOS competence. No gas venting episodes occurred either by passive leakage or by TLOSR. Cardiomyotomy with fundoplication was associated with a fall in mean LOS pressure from 14.3 ± 1.5 mmHg to 7.1 ± 1.8 mmHg but no LOS relaxation occurred during swallowing. Conclusion : Nissen fundoplication is highly effective in preventing reflux across a normal or chronically hypotensive LOS. Fundoplication results in a constant, measurable pressure barrier at the lower end of the oesophagus that is not due to a change in intrinsic LOS tone. Following fundoplication TLOSR are prevented by the constant low‐pressure barrier.