Table 1

Checklist on cohort studies based on SIGN 50 comparing microsurgery (MS) and radiosurgery (RS) for solitary vestibular schwannoma

Authors and publication yearPollock 200610Myrseth 200911Pollock 199512Myrseth 200515Regis 200214Karpinos 200213
DesignProspective consecutive predefined inclusion criteriaProspective consecutive predefined inclusion criteriaRetrospective consecutive matched controlsRetrospective consecutive matched controlsRetrospective non-consecutive matched controlsRetrospective consecutive matched controls
Allocation to treat armPreference patientPreference patientPreference patient and surgeonPreference patient2 hospitals, preference by surgeon/patientMiscellaneous criteria by surgeon
 Same primary endpoint: intervention-associated morbidityYesYesYesYesYesYes
Selection of subjects
 Source population: adult, solitary VS<30 mm, no previous interventionYesYesYesYesYesNo
 Eligibility criteria: proven growth or predefined cisternal sizeNoYesNoNoNoNo
 Exclusion criteria NOT more strict for MS because of age and comorbidityYesNoNoNoNoNo
 Participation rate NOT lower for MS because of specific RS referralYesNoNoNoNoNo
 Same baseline cranial nerve deficitsYesYesYesYesNoYes
 Consecutive series and loss to follow-up <10%YesYesYesYesNoNo
 Adequate analysis drop outsYesYesNoYesNoNo
Outcome assessment
 Prespecified endpointYesYesYesYesYesYes
 Mortality addressedYesYesNoYesYesYes
 Blinded outcome measurementYesNoNoNoNoNo
 Same measure new cranial nerve deficitYesYesYesYesYesYes
 Same measure quality-of-life scoresYesYesYesYesYesNo
 Repeated outcome measurementYesYesYesYesYesNo
Confounding variables
 NOT substantial larger tumour size in MS armYesYesYesYesYesNo
 NOT substantial higher age in RS armNoYesNoNoNoNo
 NOT less fit patients in RS armYesNoNoNoNoNo
 One single intervention in each armYesYesYesYesYesNo
Statistical analysis
 Statistical measure of precisionYesYesYesYesYesYes
Overall assessment
 Number of relevant ‘no’000036
 Overall judgement++++++
 No commercial fundingYesYesYesYesYesYes
 No relevant bias, outcome owing to interventionYesYesYesYesNoNo
 Outcome applicable to source populationYesYesYesYesNoNo
  • Yes: well covered or adequately addressed, increasing confidence that outcome is caused by the interventions.

  • No: poorly or not addressed or not reported; cause for bias. Bold: possible relevant bias, decreasing confidence.

  • ++, All or most of the criteria have been fulfilled. Where they have not been fulfilled the conclusions of the study or reviews are thought to be very unlikely to alter.

  • +, Some of the criteria have been fulfilled. Those criteria that have not been fulfilled or not adequately described are thought unlikely to alter the conclusions.

  • −, Few or no criteria fulfilled. The conclusions of the study are thought likely or very likely to alter.