Discusión y análisis desde los datos

Recurrent symptomatic relapse, refractory to conservative management Significant sequelae such as laryngeal or respiratory symptoms

Grade XU / IV endoscopic oesophagitis with complementary symptoms Refluxate,predominantly bile

Documented LOS dysfunction (with poor symptom control) Alternative to life long medication

The high relapse rates associated with a conservative management regimen, combined with the refinement of surgical technique, in particular the advent o f the laparoscopic anti reflux approach has resulted in a surgical renaissance.

The main criterion for surgical intervention remain those patients with recurrent symptomatic reflux, in whom a defective LOS mechanism has been identified and have documented periods of increased acid exposure, as demonstrated by 24 hour ambulatory pH monitoring. A percentage time greater than 4 % (60 minutes) where the distal oesophageal epithelium is exposed to the acid refluxate is considered significant.

l.lO ii A comparison o f medical management vs surgery in GORD.

There is little comparative data that has examined conservative therapy versus surgery in the management of GORD. One study compared the role o f H: receptor antagonists with the open Nissen fundoplication procedure and found that the latter was associated with a lower relapse rate (Spechler, 1992). The relevance o f this landmark paper was been diminished through the increased use o f proton pump inhibitors in the primary management o f GORD.

A randomised trial comparing Omeprazole 20 mg versus open antireflux surgery (ARS), also favored surgery, when comparing treatment failure rates. On increasing the dose o f Omeprazole to 40 mg, similar levels o f symptom control were obtained and no statistically significant difference was noted between either group (Lundell et al, 2001).

This paper, however, did not routinely perform hiatal hernia repair in the ARS group and did not incorporate any laparoscopic patients.

A more recent study, randomised 57 patients with significant GORD to either PPI therapy ( n = 29) or laparoscopic anti reflux surgery (LARS) ( n = 28). Preliminary results at 3 months revealed a similar reduction in reflux in both groups as defined by a reduction in DeMeester score to 11 in both groups (originally 21 in the PPI group and 20 in the LARS group) and an increase in the LOS pressure to 15 mmHg and 17

mmHg in the PPI and LARS groups respectively. Original LOS pressures were 10 mmHg in the PPI and 7 mm Hg in the LAJIS group (Decadt et al, 1999).

l.lOiii The principles o f open Nissen fundoplication.

The technique of fundoplication was intially described by Nissen in 1956. The procedure involved a 360 degree posterior wrap, incorporating the gastric fundus around the distal oesophagus and the LOS. The dramatic symptomatic improvement experienced, prompted the universal acceptance o f the procedure. This was tempered by later morbidity which resulted in modifications to the initial description.

The principles of a modern Nissen fundoplication involve crural repair o f the oesphageal hiatus, mobilisation of the gastric fundus to ensure a tension-free wrap, which is enabled through the division of the short gastric vessels and the use of a large 50 - 60 Fr

oesophageal bougie. The suture line o f the wrap is maintained relatively short and should not exceed 2-3 cms, to reduce the incidence o f post operative dysphagia.

The gastric wrap should only incorporate the fundus. The vagal trunks should not be included, as swallowing and relaxation o f the LOS and gastro oesophageal junction is mediated by the parasympathetic nervous system (DeMeester, 1996). The type o f gastric wrap used, is very much operator dependent. Evidence of impaired or delayed peristalsis, as documented by oesophageal manometry (Kahrilas et al, 1986) has in the past resulted in a tendency to fashion a loose, partial wrap. However, this has not been a universal policy and good post operative outcomes have been documented, despite pre operative evidence o f impaired peristalsis (Mughal et al, 1990; Beckingham et al, 1998).

l.lO iv The rationale fo r anti reflux surgery.

Recreation of a competent physiological LOS is an integral part of fundoplication. Post fundoplication LOS pressures should be elevated to approximately three times basal gastric pressure to enable the formation o f an LOS pressure gradient between the distal

oesophagus and proximal stomach. This ensures the intragastric pressure required to initiate post operative reflux is far greater, which enables LOS competency to be maintained (DeMeester et al,1979, DeMeester, 1996). Restoration of LOS pressure is created by a squeeze effect, produced by the smooth muscle o f the fundus and the enhanced intrinsic action o f the LOS, due to the gastric wrap. Evidence for the former has been obtained from animal studies where the distal oesophageal smooth muscle was excised, leaving the oesophageal mucosa intact and then wrapping the gastric fundus around the LOS, in a manner similar to that used in a fundoplication procedure (Condon et al 1976). In a similar study, the distal oesophagus was resected and replaced by the proximal stomach (Moosa et al 1978). Enhanced LOS pressures were demonstrated in both studies.

The enhanced mechanical performance o f the LOS is also attributable to the formation of a “mucosal flap valve” effect, produced by the development o f a mucosal ridge, accentuating the oblique angle o f entry at the gastro oesophageal junction. This in combination with the reduction in diameter o f the distal oesophagus, produced by the gastric wrap (using the law o f Laplace the smaller the radius of a tube, the greater the pressure required to distend it) results in increased proximal gastric pressures required to initiate a reflux episode (Peterson et al, 1980). The gastric wrap reduces the proximal gastric pressure due to an alteration in gastric wall distraction forces, from the proximal stomach to the distal oesophagus, such that larger gastric pressures are required to initiate reflux (Samelson et al 1983).

Restoration of LOS length inclusive o f intra-abdominal length and thus by definition the length o f the high pressure zone, is also a fundamental feature o f the procedure (see section l.Sviii (Little, 1996). The reconstructed LOS, or alternatively the length of the wrap should ideally be approximately 2.0 cm in order to prevent reflux due to gastric distension. This may cause LOS shortening in a manner similar to which a balloon neck shortens during distension (DeMeester, 1996).

The most effective location for the refashioned LOS remains a matter for debate. An intra abdominal site ensures the effective and equal transmission o f pressure across the LOS such that it is equally distributed during a reflux episode(DeMeester et al, 1979). The continued integrity o f the intrathoracic LOS has been explained by the effective distribution of pressure from the stomach through to the wrap and then onto the distal oesophagus (Pennell, 1981). In both instances, the equal distribution of pressures on

either side of the LOS, reduces the potential increase in intragastric pressure which would promote reflux.

The improvement in oesophageal peristalsis may be due to the improvement in oesophageal epithelial sensation, promoted by the oesophagitis healing (Eastwood GL et al, 1975). An alternative proposal is that on creation o f a competent LOS and restoration o f LOS length, the contractile function o f the distal oesophageal smooth muscle is improved back to near normality (Beckingham et al 1998).