McKenna 1996.

Methods	Randomised controlled trial of 2 interventions Method of randomisation: not described Allocation concealment: not described Outcome assessor blinding: not blinded Withdrawals/Dropouts: fully accounted for
Participants	Screened: not stated Eligible: 72 Randomised: 72 (laser 33; staple 39) Completed: 62 (laser 26; staple 36) Mean age in years (SD): 67 (7) Diagnosis: CT scan Emphysema: diffuse, heterogeneous, bullae < 5 cm Diseases included: not stated Major exclusions: smoking, no prior thoracic surgery, age > 75 years, CO2 retention > 55 mmHg, severe cardiac disease, cancer within the past 5 years, ventilator dependency, presence of a lung mass, bullae > 5 cm Baseline SF‐36: not stated 6MWD (SD): not tested FEV1 in litres (SD): 0.7 (0.2) for laser vs 0.7 (0.2) for staple RV in litres (SD): 5.1 (1.1) for laser vs 5.4 (0.2) for staple TLC in litres (SD): 7.6 (1.4) for laser vs 7.9 (1.3) for staple PaO2 in mmHg: 65 for laser vs 66 for staple PaCO2 in mmHg: 43 for laser vs 44 for staple DLCO in mL/min/mmHg: 5.4 for laser vs 8.6 for staple
Interventions	Laser Extent: bilateral/unilateral ‐ unsure Approach: thoracoscipic Resection method: Nd: YAG (neodymium yttrium‐aluminium‐garnet laser) Non‐surgical: postop pulmonary rehab continued for 2 to 3 weeks after discharge Medications: not clear Stapling Extent: unilateral Approach: thoracoscipic Resection method: stapling with bovine pericardium reinforcement Non‐surgical: postoperative pulmonary rehabilitation continued for 2 to 3 weeks after discharge Medications: not clear Other: All participants in both groups were educated and were encouraged to join a Better Breathers Club.
Outcomes	Morbidity, air leaks, delayed pneumothorax, FEV1, MOS‐36, operation time (hours), length of stay, supplemental oxygen therapy, repiratory failure
Notes	"Supported in part by Department of Education grant DEf603‐ 91 ER61227 and National Institutes of Health grant R01192"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation mentioned but methods not described
Allocation concealment (selection bias)	Unclear risk	Unclear ‐ Study authors mention that “…patients were blindly randomized…”, but methods were not described.
Blinding of participants and personnel (performance bias) All outcomes	High risk	LVRS does not lend itself to blinding.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention of blinding of outcome assessors
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Methods of handling outcome data missing from questionnaires (if any) not described
Selective reporting (reporting bias)	Unclear risk	Prespecified published protocol not available for comparison
Other bias	Low risk	No other biases identified