Chaudhry 2011.

Methods	Design: parallel‐group, 2 arms Country: Pakistan Multisite: no Needle tip used: atraumatic vs traumatic Needle diameter used: 25 G Number of attempts: unknown Procedure: anaesthesia Site of the puncture: L2‐3 or L4‐5 Training level of those who administered the puncture: unknown Median or paramedian technique: median approach Type of anaesthetic: hyperbaric 0.5% bupivacaine 2 ml to 4 ml
Participants	1. 200 patients enrolled (patients from different surgical departments of Nawaz Sharif Social Security Hospital Lahore having different surgical procedures on the lower abdomen and lower limbs such as hernias, amputations, debridements, vesicolithotomy, total hip replacements, tibial nailing or plating, external fixators, caesarian sections and hysterectomies) Excluded patients: patients with systemic disease such as uncontrolled diabetes mellitus and hypertension, congestive cardiac failure, severe anaemia, pulmonary oedema, coagulopathies and vertebral column deformities Patients randomized to: Pencil point (100, 50%) Quincke (100, 50%) 2. No patients were excluded 3. Main characteristics of patients: Age (mean, SEM): pencil point group: 45.9, 2.81; Quincke group: 40.9, 2.05 Weight (mean, SEM): pencil point group: 63.9, 3; Quincke group: 61.7, 2.13 Gender ‐ male (number): pencil point group: 65; Quincke group: 70
Interventions	25 G pencil point needle 25 G Quincke needle Co‐intervention: needle directed cephalic slightly upwards towards umbilicus
Outcomes	Outcomes were not classified as primary or secondary PDPH: postural headache, aggravated by standing, or sitting up, and relieving by lying down Characteristics of headache: severity, localization, character, duration, presence or absence of associated symptoms Factors: grade the dural click as distinct or indistinct, speed of CSF back flow was immediate, delayed or slow, aspiration of CSF as easy, slow or impossible, ease of injection as acceptable or unacceptable
Notes	Trial registration: not stated Funder: not stated Role of funder: not stated A priori sample size estimation: no Conducted: not stated Declared conflicts of interest: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information to score this item as low or high risk of bias. Quote: "Two groups consisting 100 patients each were randomly chosen". (page 1)
Allocation concealment (selection bias)	Unclear risk	Insufficient information to score this item as low or high risk of bias
Blinding of participants (performance bias)	Unclear risk	Insufficient information to score this item as low or high risk of bias
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to score this item as low or high risk of bias
Incomplete outcome data (attrition bias) All outcomes	Low risk	No patients were lost to follow‐up
Selective reporting (reporting bias)	High risk	Several outcomes unreported in results section: speed of CSF back flow, aspiration of CSF, ease of injection
Other bias	Low risk	No other biases were identified