Buttner 1990.

Methods	Prospective, randomized, double‐blind study
Participants	A total of 400 patients who received spinal anaesthesia for operation of the lower extremities
Interventions	Patients were randomly assigned to 2 groups (25 G Whitacre and a 25 G Quincke needles) and were interviewed postoperatively on days 1, 3, 5 and 7 to assess PDPH
Outcomes	The primary outcome was PDPH. Secondary outcomes were: duration of PDPH, non‐postural headache and the duration of non‐postural headache.
Notes	—