The primary assessment is the safety of the intervention. The safety endpoint is the incidence of adverse events and defects. It is assumed that adverse events or defects will be induced by the materials in the trial, transportation, and/or skin biopsy for fabricating the material.
The secondary assessment is efficacy. Several analyses will be performed to capture aspects of the sensory and motor nerve systems and physical function of the affected forelimb, including: sensory functional test; impairment assessment of the upper limb; and motor nerve function analysis.
2.10.1. Sensory functional tests: SWT, s2PD, and m2PD
The median and ulnar nerves were compounded in the carpal tunnel. SWT is a widely used clinical test to quantify sensibility in patients with Carpal Tunnel Syndrome . It measures the response to touching sensation of the monofilaments according to a numerical quantity. Based on the results, grading is divided into three categories: excellent, good, and poor . The s2PD and m2PD are also common in the battery of sensory tests, and are used in subjects with median and ulnar nerve injuries on the upper limb [17, 18]. The length of the two-point discrimination was assessed. For each test, grading will be classified as excellent, good, or poor based on the results .
2.10.3. Motor nerve function analysis
Three types of analyses will be performed to assess motor nerve function in the median and ulnar nerves. The “Perfect O” sign, which can be used to grossly verify function in the median nerve and specifically test the anterior interosseous nerve, is a common physical examination tool and is used in clinical practice . The collapse of the Perfect O sign reflects reduced functionality and muscle weakness innervated by the median nerve. “Froment’s sign” is a well-known physical examination of the hand to test for palsy or disability of the ulnar nerve. It is used to evaluate the strength of the adductor pollicus of the thumb, which is innervated by the ulnar nerve. A positive sign reflects reduced functionality and muscle weakness in the pinch grip . Similar to hand action, tip pinch and key pinch strength are widely used as functional tests of motor nerves in the hand . The “manual muscle test (MMT)” is used as a motor nerve functional test to assess the quantitative maximum force of muscles associated with the median and ulnar nerves. The MMT is widely used to evaluate the maximum force a muscle is capable of generating, and its reliability has been confirmed . It is scored on a scale graded from 0 to 5, with grade 5 indicating normal muscle function and grade 0 indicating complete paralysis . This will be applied to the participants, as appropriate.
2.11. Assessment of adverse events
All adverse events will be assessed and recorded according to trial site and patient, and reported in a predesigned booklet throughout the entire course of the study including: date of the initial event; policy decision date; details of adverse event(s); total number of adverse events; total number of follow-up days (number of days in the observation period). All adverse events including the number of patients who experienced at least one adverse event and number of patients who discontinued treatment due to adverse events will be reported to the data center and handled in accordance with regulatory requirements. The safety assessment committee will be asked to advise in cases in which the endpoint may be affected.
2.12. Data analysis
The efficacy analysis subject group will include participants who are assessed at least once after transplantation. Individuals committing a serious violation of the study process or GCP, and/or demonstrate noncompliance after registration, will be excluded. The safety analysis subject group includes participants who undergo skin biopsies after registration. Problematic data will be discussed and judged by the physician and the chief of statistical data analysis to determine whether they will be included in the analysis. Missing data will not be imputed. Details regarding problematic data (e.g., item name, content, and decision date) will be recorded. Intermediate analysis is not scheduled to be performed. Demographic data will be assessed for the proportion of each item. Measurable demographic data will be assessed using summary statistics.
The main analysis, is safety analysis, will be conducted for the safety analysis subjects. The number of adverse and fault events that are likely related to the products in or processes of transplantation after skin biopsy will be counted. In addition, the percentage of each event will be calculated using the results from all samples.
The results of the sensory functional analysis will be used for sub-analysis. In the efficacy analysis subject group, the time transition from transplantation to 48 weeks after transplantation and the maintenance factor will be assessed for the results of SWT, s2PD, and m2PD. All analyses will be performed using JMP Pro 15 (SAS Institute, Cary, NC, USA).
2.13. Sample size
It takes 60 days to obtain the transplantation materials after skin biopsy because conduit maturation requires extensive processes and time; moreover, there is only one available device for the protocol. Furthermore, the device can culture only a single conduit at once to avoid contamination from other patient samples. Therefore, it is difficult to overlap the protocol duration for each patient because safety will be confirmed in each step of the study. From the perspective of feasibility and ensuring safety, a sample size of three, as the initial set up, was agreed upon to complete the clinical protocol.
2.14. Data collection and management
Investigators and clinical research coordinators will be advised to complete case report forms in the booklet while following instructions. Each completed booklet will be copied to the attending physician and submitted to the data center at the Institute for Advancement of Clinical and Translational Science (iACT). The data in the booklet will be entered into a database using a double-entry method. Data quality will be validated by checking for missing and out-of-range values.
The data will be stored in the data center and housed in a secure server to maintain participant anonymity. Participants will not be identified by their names, addresses, or telephone numbers, but by unique case registration numbers in combination with the date of the investigation.
An independent data monitoring committee has been established to assess safety data if serious adverse events should occur, and to assess whether the per-protocol set requires any modification(s). A qualified and independent auditor has been appointed to audit the trial systems and trial conduct before and during the study in accordance with a written procedure.
2.16. Reporting checklist
The Standard Protocol Items: Recommendations for Interventional Trials (i.e., SPIRIT) reporting guidelines were used to compile the checklist for this protocol (Supplemental Fig. 1).