Here is the design of a clinical trial:

Official Title: The Effect of Extracorporeal Shock Wave Therapy (ESWT) in Acute Traumatic Complete (AIS A) and Incomplete (AIS B-D) Cross-sectional Lesions on Motor and Sensory Function Within Six Months After Injury: A Two-arm Three-stage Adaptive, Prospective, Multi-center, Randomized, Double-blind, Placebo-controlled Clinical Trial

Included conditions:
- Acute Traumatic Spinal Cord Injury

Study Armgroups:
- {'label': 'ESWT', 'type': 'EXPERIMENTAL', 'description': 'The extracorporeal shockwave therapy is applied once at the level of lesion and 5 segments above and below; or below the occiput (in lesions higher than C6) and above the sacrum (in lesions lower than T12). In addition, the ESWT is applied to the soles of both feet on the medial side of the plantar surface. The ESWT is applied as soon as possible within 48 hours post-injury.', 'interventionNames': ['Device: Shock waves']}
- {'label': 'Control', 'type': 'SHAM_COMPARATOR', 'description': 'In the control group, the same procedure is performed, but without the device emitting extracorporeal shock waves using a dummy head.', 'interventionNames': ['Device: dummy head']}

Interventions:
- {'type': 'DEVICE', 'name': 'Shock waves', 'description': 'The shockwave generator orthogold 100® generates high-energy acoustic waves that behave much like other sound waves except that they have much greater pressure and energy. As with sound waves, Spark Waves® can easily travel great distance as long as the acoustic impedance stays the same.', 'armGroupLabels': ['ESWT']}
- {'type': 'DEVICE', 'name': 'dummy head', 'description': 'The shockwave generator orthogold 100® will be used in combination with a dummy head, to Refrain shock waves', 'armGroupLabels': ['Control']}

Primary Outcomes:
- {'measure': 'changes in total motor scores (TMSC) = TMSC after 6 month minus TMSC at baseline', 'description': 'greater improvement in motor and sensory function (the AIS grade) can be achieved in patients after spinal trauma (AIS A-D) by applying a single extracorporeal shockwave therapy compared to the control group.', 'timeFrame': 'day 0 to 6 month'}

Please estimate the sample size based on the assumption: 
A one-sided error rate of 5% and a planned power of 80% are used. The triangle test is selected for upper and lower limits. Interim evaluations are conducted at stages 1 and 2 to determine early termination based on success or lack of efficacy.
Study sample size
          Sample size calculation is usually based on an effect size expected from a given treatment. Due to a lack of knowledge about the effects of EWST on sensory (SF) and motor functions (MF), such an estimation is limited. For this reason, a so-called adaptive design was chosen, corresponding to the âmulti-arm multi-level approachâ (MAMS approach) proposed by Jaki et al. [65]. The advantage of this design is that the effect size needed to calculate the sample size is not based on specific values, but on probabilities (p and p0) that can be used to identify the desired or the uninteresting effect. The probability p = 0.6 chosen for the study for the desired effect means that a randomly selected person in the treatment group has a 60% probability of achieving a better result than a randomly selected person in the control group. The uninteresting effect is assumed with a probability of p0 = 0.5. This value means that both the novel treatment and the placebo treatment perform equally well (Jaki et al., 2019). Another advantage of MAMS is that this form of sampling does not require any knowledge of the variance of the endpoint variables. All the calculations required for this are implemented in an R package and published accordingly (Jaki et al., 2019).
          A two-armed, three-stage adaptive study design is envisaged at Neurowave. In stage 1 and stage 2, interim evaluations are carried out to determine whether the study can already be terminated. This will be the case if either the intended and thus desired result can already be sufficiently confirmed, or it becomes apparent that the study will not be a success. These interim evaluations offer the opportunity to shorten the study. If none of these two cases occur, the study will continue up to stage 3. The overarching advantage of this design is that the smallest possible number of patients can be found to demonstrate a medically relevant effect.
          With a one-sided error rate of 5% and a planned power of 80%, the following design parameters could be calculated. For the upper and lower limits, the triangle test is selected [65].
Stage 1Stage 2Stage 3Cumulative sample size (control):4182123Cumulative sample size (treatment):4182123Maximum total sample size: 246Upper bound2.131.891.85Lower bound0.001.131.85p-value for H1 ((stopping for) success)0.0180.0310.033p-value for H0 (stopping for a lack of efficacy)0.5000.130Continue as planned at stage 1: 0.500 > p >â 0.018Continue as planned at stage 2: 0.130 > p >â 0.031The calculation was done with the R package MAMS