Forty-three studies were included (n=1,791, range 10 to 125): 12 RCTs (n=587) and 31 uncontrolled studies. Two RCTs were deemed high quality (Jadad score 3) and 10 were deemed low quality (Jadad score 2): three reported their randomisation method; all explained withdrawals; and none were clearly blinded or described allocation concealment.
The remission rate was significantly higher in the pneumatic dilation group than in the BoTx group (risk ratio 1.47, 95% CI 1.23 to 1.77, p<0.0001, I2=7.8%; seven RCTs) and the relapse rate was significantly lower (risk ratio 0.32, 95% CI 0.16 to 0.65, p<0.001, I2=0%; three RCTs).
Remission was significantly more likely with a combination of BoTx and pneumatic dilation than with pneumatic dilation alone (p<0.05; one RCT, n=43).
Remission rate was significantly superior with Heller myotomy than with pneumatic dilation (risk ratio 1.48, 95% CI 1.15 to 1.99, p=0.002, I2=49.7%; two RCTs), with no statistically significant difference in the complication rate.
There was no statistically significant difference in the remission rate between laparoscopic and thoracoscopic myotomy (two RCTs).
Pneumatic dilation had a weighted mean remission of 86.6% (standard error 23.9) and a relapse rate of 10.7% (standard error 21.0) (five studies, n=667).
Heller myotomy had a weighted mean remission of 94.8% (standard error 10.6) and a relapse rate of 1.5% (standard error 6.3) (five studies, n=354).
Thoracoscopic myotomyhad a weighted mean remission of 92.0% (standard error 10.0%) and a relapse rate of 4.91% (standard error 9.0) (three studies, n=64).
Adverse effects of treatment:
These included chest pain (associated with BoTx) and perforation and gastro-oesophageal reflux (associated with pneumatic dilatation).
Pneumatic dilation was significantly more effective in uncontrolled than in controlled studies.