Although we found no change in the absolute number of myotomies or in the rate of previous endoscopic therapy, Heller myotomy was performed on an older population and at a shorter time interval from the last endoscopic treatmentin the postlaparoscopy group. These changes suggest that the threshold for referral to myotomy may have diminished concurrently with the introduction of minimally invasive myotomy.Despite ongoing controversy surrounding the use of fundoplication with myotomy, the proportion of procedures, including an antireflux procedure, increased approximately fivefold during the study period. Whether this reflects an increase in the use of a transabdominal over a transthroacic approach is not available in the RAMQ database. However, this finding is consistent with a recent prospective randomized trial supporting routine fundoplication after myotomy. flovent inhaler
Data from these single-centre studies may be biased by the fact that the patients are often referred precisely for the surgical procedure; thus, data may be skewed by local referral patterns. To eliminate this selection bias, we investigated the regional referral patterns by two additional methods. RAMQ demonstrated that the absolute number of myotomy procedures remained stable (approximately 30 per year) over a five-year period centred on an arbitrary date at which minimally invasive surgery for achalasia was presumed to have become generally available (January 1, 2000). Unfortunately, the RAMQ billing code does not distinguish between open and minimally invasive procedures. The proportion of patients receiving previous endoscopic therapy also remained stable over this time period. Of interest was that the rate of previous endoscopic therapy in the RAMQ database was lower than that in our own institution. Some patients receivedtreatmentbefore 1997, and a few received therapy outside of the province. In addition, as with all administrative databases, miscoding and under-representation of cases or procedures is commonplace , and represents an inherent weakness in this type of study. Particular to the present study, no separate billing code for the two commonly used endoscopic therapies (Botulinum toxin injection and pneumatic dilation) exists. Rather, a catchall code for any esophageal endoscopic intervention (injection, dilation, sclerosis or ligation) is used. Clearly, some endoscopic therapies may have been miscoded, resulting in under-reporting. Nonetheless, it is fair to assume that this potential miscoding would be equally distributed across the years under study; thus, trends intreatmentshould remain valid.