Langenbach 2020.

Study characteristics
Methods	Randomised controlled trial Location Department of Surgery, Helios St. Elisabeth Klinik Oberhausen, Germany Study dates  Between January 2016 until January 2018
Participants	Inclusion criteria Abdominal wall hernia needing open surgery, written informed consent, no co‐existing chronic diseases with permanent use of analgesics, no neuro‐muscular diseases with chronic pain sensation, no emergency operations or other simultaneous interventions, no pregnancy or patients with previous IPOM procedure Patient characteristics (absorbable tacks (28) / absorbable sutures (20)) Age (mean, SD): 62.2 (15.3), 61.4 (12.8) Gender (male, %): 11 (39%) / 8 (40%) BMI (kg/m2, mean, range): 34.0 (6.6) / 31.2 (6.3) Hernia type (incisional, %): 20 (71%) / 17 (85%) Hernia size (median, range): 33 (4 – 204) / 46 (4 – 616) Comorbidity: Hypertension: 18 (64%) / 11 (55%) Diabetes: 9 (32%) / 7 (35%) COPD: 4 (14%) / 2 (10%) Coronary Heart Disease: 5 (18%) / 4 (20%)
Interventions	Intervention/control: absorbable tacks (2 cm distance) compared to absorbable sutures (2 cm distance) Mesh: composite mesh Intra‐abdominal mesh position: IPOM Surgical approach: open
Outcomes	Recurrence (1 year), pain (primary outcome), HRQOL, return to activity, postoperative complications, duration of surgery
Notes	Funding source(as originally reported) Not reported.  Declarations of interest for the primary investigators (as originally reported) There is no conflict of interests Data for sensitivity analyses Randomised: 28/20 Analysed: not reported Imputed in ITT sensitivity analysis: not applicable
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random list
Allocation concealment (selection bias)	Low risk	Group allocations were stored in sequentially‐numbered opaque, sealed envelopes
Blinding of participants and personnel (performance bias) All outcomes	High risk	Surgeon not blinded. Other caregivers and participants unclear
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported. Tendentially recurrence "lower risk" (objective outcome), pain "higher risk" (subjective outcome)
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts
Selective reporting (reporting bias)	Low risk	The study protocol is not available but it seems that the published reports include all expected outcomes, including those that were prespecified
Other bias	Low risk	None detected