Table 1.
List of parameters used in the model.
| Parameter | Value | Reference |
|---|---|---|
| Probabilities: PTNS | ||
| Probability of >50% improvement in FI for PTNS | ||
| base case | 0.59 | Thin and colleagues4 |
| lower limit | 0.59 | Thin and colleagues4 |
| upper limit | 0.71 | Thin and colleagues4 |
| Probability of discontinuation for PTNS | 0.04 | Peters and colleagues16 |
| Probability of proceeding to SNS after failing PTNS | ||
| base case | 0.96 | Assumption: probability of not proceeding to SNS equal to probability of discontinuation for PTNS |
| lower limit | 0.50 | Assumption |
| upper limit | 1.00 | Assumption |
| Probabilities: SNS | ||
| Probability of receiving permanent SNS | ||
| base case | 0.77 | Thin and colleagues4 |
| lower limit | 0.40 | Thin and colleagues4 |
| upper limit | 1.00 | Thin and colleagues4 |
| Probability of >50% improvement in FI for permanent SNS (short term) | ||
| base case | 0.79 | Thin and colleagues4 |
| lower limit | 0.69 | Thin and colleagues4 |
| upper limit | 0.83 | Thin and colleagues4 |
| Probability of >50% improvement in FI for permanent SNS (long term) | ||
| base case | 0.84 | Thin and colleagues4 |
| lower limit | 0.75 | Thin and colleagues4 |
| upper limit | 1.00 | Thin and colleagues4 |
| Probabilities: adverse events temporary SNS | ||
| base case | 0.22 | Hetzer and colleagues12 (joint probability of adverse events: pain in the stimulation site 0.06, wound infection 0.08, electrode defect/dislocation 0.08) |
| lower limit | 0.02 | Prapasrivorakul and colleagues17 |
| upper limit | 0.35 | Van Kerrebroeck and colleagues20 |
| Probabilities: adverse events permanent SNS | ||
| base case | 0.35 | Hetzer and colleagues12 (joint probability of adverse events: pain in the stimulation site 0.17, wound infection 0.09, electrode dislocation 0.09) |
| lower limit | 0.13 | Jarrett and colleagues14 |
| upper limit | 0.38 | Mellgren15 |
| Probabilities: maintenance SNS | ||
| Battery change | 0.08 | Hollingshead and colleagues13 |
| MRI scan: | 0.02 | Tjandra and colleagues19 |
| Health utilities | ||
| Persistent FI | ||
| base case | 0.69 | Harvie and colleagues11 |
| lower limit | 0.56 | Soria-Aledo and colleagues18 |
| upper limit | 0.68 | Van Wunnik and colleagues21 |
| >50% reduction in FI | ||
| base case | 0.77 | Harvie and colleagues11 |
| lower limit | 0.63 | Soria-Aledo and colleagues18 |
| upper limit | 0.86 | Van Wunnik and colleagues21 |
| Adverse events | ||
| base case | 0.46 | McDermott and colleagues26 (pain severity: moderate) |
| lower limit | 0.67 | McDermott and colleagues26 (pain severity: mild) |
| upper limit | 0.16 | McDermott and colleagues26 (pain severity: severe) |
| Adverse event duration | ||
| base case | 7 days | NHS England. Consultant-led referral to treatment waiting times. Annual report27 |
| lower limit | 3 days | Assumption |
| upper limit | 14 days | Assumption |
| Discounting rate | ||
| base case | 3.5% | NICE28 |
| lower limit | 1.5% | NICE28 |
| upper limit | 6.0% | Claxton and colleagues29 |
PTNS, percutaneous tibial nerve stimulation; SNS, sacral nerve stimulation.