1.1 Study design and ethics statement
This was a single-blinded, randomized controlled efficacy trial with 2 parallel groups and intention-to-treat analysis. The study protocol has been approved by the Zhejiang Rehabilitation Medical Center Medical Ethics Committee.(ZKLL20221014). All patients were informed of the procedure, the use of their data and images for research. They understood the purposes and provided written informed consent according to the 1964 Declaration of Helsinki prior to their participation. This clinical trial has been registered with the China Clinical Trials Registry, registration number: CHiCTR2300070068.
1.2 Participant recruitment
From June 2020 to June 2021, we prospectively enrolled all patients individuals with a diagnosed SCI, These patients came from 6 units of Zhejiang Rehabilitation Medical Center(Affiliated Rehabilitation Hospital of Zhejiang Chinese Medical University), According to the total effective rate of 90% in our preliminary small sample clinical observation, taking the bilateral a=0.05,1-β=0.90, according to the "Medical Statistics - Postgraduate Teaching Book (Second Edition, People's Health Publishing House)" Schedule 17 (the sample content required for comparison of the mean of two samples), we found that the minimum sample size of each group is 26. A total of 52 cases, an increase of 15% of cases lost, so each group of samples taken 30 cases, the total number of cases 60 cases; Inclusion criteria are: (1) Patients meet the International Standard for Neurological Classification of Spinal Cord Injury published by the American Spinal Injury Association (ASIA ) [5], with clear clinical manifestations of spinal cord injury and spinal cord lesions confirmed by CT or MRI. (2) Patients have a duration of the disease for more than six months. (3) Patient are graded as C/D according to ASIA classification (4) The injured segment of patients are: T10-L2. (5) Muscle tone of each muscle group in both lower limbs of patients is ≤2 levels. (6) Patients have no cognitive, visual, or auditory dysfunction, and are able to communicate normally with the therapist and follow the therapist advice to do rehabilitation exercises. (7) Patients can walk with assistance or independently. (8).have a body mass index (BMI) < 30, and be cognitively unaffected. Exclusion criteria are: (1) Patients have complete spinal cord injury. (2) Patients have fractures, contractures, or deformities in the lower limbs. (3) Patients have other underlying diseases in multiple organs and systems. (4) Patients have other medical diseases that affect functional walking training. (5) Patients have communication problems and do not follow medical orders. (6) Patients quit the experiment.
1.3 Randomization and blinding
We use the method of centralized stochastic system, The individuals were randomly divided into the experiment group or control group in a 1:1 ratio by simple randomization method, using computer-generated simple random tables. A researcher does not know how to group patients until he or she confirms whether a patient is formally enrolled in a clinical trial
The sequences were preserved by one researcher who did not participant in the trainings and assessments ,10MWT、Holden walking function 、ASIA Lower Limb Movement Score(LEMS) 、Lower Limb Movement Score(LEMS) and BBS assessment of individuals pre- and post-training were performed by the same two clinical researchers who were blinded and did not know whether the individual was in experiment or control group. The electromyography of the lower limbs was performed by two researchers who are familiar with surface EMG manipulation and assessment and do not know which group the patient belongs to. Clinical data was recorded after averaging.
1.4 Interventions
Both groups received symptomatic treatment with conventional drugs, such as lowering blood pressure, adjusting blood sugar and lipid, reducing pain and nerve nutrition.
1.4.1.Experimental group: Patients underwent lower limb rehabilitation robot-assisted walking function training (see Figure 1 and 2). The lower limb rehabilitation robot in this study is provided by Rambler Rehabilitation Equipment Co., LTD. The regular model is GR-A1, and the mechanical power is 100. for patients who needed to lose weight, and the patient was given suspension training using the suspension weight reduction system. Some of the patients lost weight through the straps on the chest and waist. The weight reduction generally started from 50% of the body weight of the patients, and then could be gradually reduced to 0 % (0% of their body weight). The six straps of the robotic arms on both sides were tied to the thighs, calves and soles of their lower limbs and fixed securely. The initial velocity was 1.2 m/s, the initial hip angle was set at 45 degrees, and the initial knee angle was set at 66 degrees. The therapist could determine various initial parameters of gait of a new patient through experience and communication about the walking habits of patients and adjust the robot moment arm length according to the length of the patients’ limb. During the training process, the rehabilitation therapist would also adjust the gait parameters of patients according to the motion control system and information recording system of lower limb robot at any moment. The training was divided into 12 weeks and maintained a 45-minute walking training per day.
receiving training with rehabilitation robot
1.4.2.Control group: The control group was given routine walking function training: (1) PT training: some strength training equipment such as sandbags were employed to carry out resistance training of the hip flexion and extension, knee flexion and extension, and ankle flexion and extension of muscle groups in both lower limbs for patients. This helps to enhance the muscle strength training of the key muscle groups in both lower limbs. At the same time, some traction techniques and exercise equipment were used to improve the joint mobility of the major joints of both lower limbs to avoid the degeneration of joint mobility. (2) Balance function training: this training could gradually train and improve the balance function of sitting, standing and walking for both groups of patients. (3) Standing training: this training could be conducted with the assistance of a standing bed. It could train the cardiopulmonary adaptability of patients and promote their blood circulation in both lower limbs, thus effectively preventing postural hypotension and laying the foundation for future walking function training. (4) Walking training: according to their functional improvement, patients gradually changed from walking training in the balance bar to walking training with the assistance of a walker from level ground and slope, and to stair training. This training was conducted once a day, and maintained 45 minutes per day for 12 weeks in total.
1.5. Measures:
Outcome measures were collected and analyzed at the baseline and end of 12 weeks of rehabilitation treatment.
1.5.1.Primary outcome: The surface electromyography device used in this study is Noraxon MR(Version:3.18,USA)software, and the electrodes are two Ag/AgCI circular electrode disks, surface EMG signals were detected for the muscles: rectus femoris, anterior tibialis, biceps femoris, and gastrocnemius and can be identified by palpation, The analysis mode of Time-frequency analysis is adopted,The x-axis of the abscissa represents the time, and the y-axis of the ordinate represents the amplitude(pV), Before treatment and after 12 weeks of treatment, patients were asked to lie flat or sit in front of a monitor ,The surface electromyography is applied to the highest part of the muscle belly bulge of the target muscle. They were also instructed to do movements that maximized their hip joint extension, knee flexion and extension, ankle dorsiflexion and ankle inversion. applying resistance to the patient at the same time, the patient was instructed to confront the resistance, extend the hip, flex the knee, extend the knee, dorsally extend the ankle joint and externally turn the ankle joint with maximum force, and perform the movement and relaxation according to the collector's command, for a total of 3 times, each time lasting 5 seconds, in order to avoid the patient's muscle fatigue caused by repetitive movements in a short period of time and interference with the collection results, at least 1min or more should be maintained between each two collections Interval time, The signal wave values per second of the target muscles were collected by electrodes and sensors. The entire signal was then filtered using a bandpass filter with a cut-off frequency range of 30-350Hz. Finally, the signals were transmitted into computer analysis by a collector. The root mean square (RMS) moving window function with a time constant of 100 ms was used for smoothing, and the surface EMG envelope was normalized to the maximum amplitude (iEMG value). The iEMG value is shown in Figure 3.
1.5.2.Secondary outcomes:10m Walk Test (10MWT) [6] is to assess the walking speed, the patients were assessed by walking as fast as possible from the starting point to the end point on a 14m long walkway. The time it took for them to pass the 3m and 13m points were recorded. This test was carried out for 3 times and the mean value was recorded (See Figure 4).
Holden walking function assessment is to evaluate their walking function, and divided into 0-5 levels. Level 0 means that the patient cannot walk and needs a wheelchair or two people to assist him/her in walking, level 1 means that he/she needs a lot of continuous help from one person, level 2 means that he/she needs a little help from one person; level 3 means supervision or verbal help, level 4 means that he/she can walk on level ground, level 5 means full independence.The higher the level, the stronger the walking ability;LEMS[7] is to evaluate their walking function by using the motor item scoring method according to the ASIA International Standard for Neurological Classification of Spinal Cord Injury (2011 revision).It is to assess the muscle strength of a total of 10 key muscles in both lower limbs, with 0-5 levels corresponding to 0-5 points,The total score of lower limb motor function score for both lower limbs was 50.Berg Balance Scale (BBS) is to assess the balance function of patients, including 14 items. Each item could be divided into five levels. Level 0 meant that patients are unable to complete the action, and level 4 meant that patients can complete the action normally. The lowest is 0 points, and the highest is 56 points. The higher the score, the stronger the balance ability.Record the incidence of adverse events in the experiment group and the control group.
1.6. Data analysis:
SPSS19.0 statistical software was used for statistics. The Shapiro–Wilk test was used to determine if data were normally distributed.These were recorded as means ± standard deviations(SDs), Independent Student t-test was used to compare continuous data related to clinical features between two groups.Paired Test Student t-test was used to compare varies between pre- and post-intervention. the rank sum test is used if the data was class distribution,Wilcoxon rank-sumtest and Mann–Whitney U test were used if the data was not normally distributed. χ2 test was used for the comparison of incidence of adverse events,In all statisticaltests, p < 0.05 was defined as significant.