Intraoperative Distensibility As Measured Using a Novel Functional Luminal Imaging Probe: Endoflip

Andrei Ilczyszyn, MBBS BScHons MRCSEng, Abrie Botha, MD FRCS. Department of Upper GI Surgery, St Thomas’ Hospital, London, UK

Objective of the Device

Several mechanisms have been proposed to explain the effectiveness of laparoscopic anti-reflux surgery (LARS), including esophageal lengthening, changing intra-esophageal pressure, hiatal repair and addition of an extra-anatomical wrap. Although LARS is associated with good long term outcomes there is still a significant number of patients with post-operative dysphagia. Various intraoperative measures have been proposed to alleviate this but none has been widely accepted.

Recent technological advances (EndoFLIP system, Crospon Ltd., Galway, Ireland) allow real-time measurement of the diameter, cross-sectional area and distensibility, giving the potential to analyze the anatomic and physiological properties of the gastroesophageal junction (GEJ) intraoperatively. We used this novel physiological device to measure distensibility of the GEJ during LARS to determine the critical components of the operation.

Description of the Device

The EndoFlip system comprises a balloon-tipped catheter connected to a display and recording unit. The system is designed so that the sensing assembly straddles the GEJ. The balloon contains 16 impedance sensors spaced 5mm apart and a single solid state pressure sensor in a 0.2% saline solution. A weak alternating current is passed within the balloon and measurement of the impedance between the electrodes allows calculation of the cross sectional area at that electrode. Further calculation using intra-balloon pressure allows calculation of the distensibility and compliance.

Preliminary Results

Methods: Laparoscopic Nissan fundoplication (LNF) was undertaken in a standard manner. Measurements were taken at 30ml and 40ml balloon distensions after induction of anesthesia and pnuemoperitoneum, dissection of the crura, after crural repair and after formation of the wrap. Data was analyzed sequentially using a paired t test, P<0.05 was regarded as significant.

Results: 9 patients were studied (6 male). Average age was 44.6 (32-67). 7 patients underwent primary LNF, 2 patients underwent revision for recurrent reflux symptoms.

LNF reduced the average distensibility of the GEJ at 30ml balloon distension from 2.01mm2/mmHg to 0.916mm2/mmHg (p=0.045) and at 40ml from 2.91mm2/mmHg to 1.10mm2/mmHg (p=0.007).

Tightening of the crura appeared to have the maximal effect with a reduction in distensibility of 86% (1.92mm2/mmHg to 1.05mm2/mmHg, p=0.087) at 30ml and 66% (2.77mm2/mmHg to 1.58mm2/mmHg, p=0.004) at 40ml. All patients were reflux free at discharge.

There were no complications from the usage of the EndoFLIP catheter in our series.


The EndoFLIP system appears to be safe and effective for intraoperative usage. It gives a new insight into the physiological mechanisms underlying LARS. Using the EndoFLIP system we have demonstrated that LNF results in an immediate reduction in OGJ distensibility, with reduction of hiatus hernia and repair of the crura being the main mechanism whereby this is achieved. Further investigation will be undertaken assess the clinical implications of this finding and also to evaluate the usage of EndoFLIP in other disorders of the GEJ.

Session: Emerging Technology
Program Number: ET011

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