Transnasal sphenopalatine ganglion block for post-dural puncture headache of moderate severity : an observer blind, parallel group randomized control trial

70 patients will be randomly devided in to two different group: SP(N=35), SS (N=35)  [SP=Sphenoealatine ganglion block ; SS=Sham block]

BP(SBP, DBP) Pulse Rate, VAS score will be studied at base line, 30 minutes, 4 hours, 24 hours, 48 hours after the procedure and by telephonic followup at 7th day.

For SPG block - Patients supine with sniffing position :- After visually inspecting each nostril two long cotton tipped applicators will be soaked in 2% lidocaine  applied and advanced until resistance is met. The procedure will be repeated in the other nostril. The applicators will be left in place for 10 minutes and 1 ml of lidocaine reapplied through the canal of the applicator and kept for another 10 minutes, after that applicators will be removed.

For SS block :- same as the procedure of SPG block here 0.9% NS (Normal Saline) will be used instead of lidocaine.

Calculation of the study is based on anticipated difference in headache intensity scored by VAS at 48 hours following the block procedure. It is calculated that 35 patients would be required in order to detect difference of 20 mm in VAS score between groups with 80% power and 5% probability type 1 error. Sample size calculation has been done by "n Master 2.0" software (Dept. of Bio-statistics, Christian Medical College, Vellore 2011)

Study will be randomized to SPG block arm and the Sham block arm using the computer generated randomized list. Allocation concealment will be by serial number opaque sealed envelop [SNOSE] technique.