Early Mobilization Following Elective Spine Surgery: Prospective Randomized Trial of In-bed Cycling on Postoperative Day 1
Phase: NA
Conditions: Spine, Post Surgery Patients, Recovery Method
Sponsor: Centre Integre Universitaire de Sante et Services Sociaux du Nord de l'ile de Montreal

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Study Protocol 
Title of the research project: 
Early mobilization after elective spinal surgery: a prospective randomized trial of in-bed cycling 
on the day following surgery 
Protocol number: 2020-2002 
Principal Investigator: 
Jean-Marc Mac-Thiong, MD, PhD, Orthopedic Surgeon 
CIUSSS du Nord-de-l’Île-de-Montréal – Hôpital du Sacré-Cœur de Montréal 
Co-Investigators: 
Andréane Richard-Denis, MD, MSc, Physiatrist 
Yvan Petit, BEng, PhD, Biomedical Sciences 
CIUSSS du Nord-de-l’Île-de-Montréal – Hôpital du Sacré-Cœur de Montréal 
Student Researcher: 
Justin-Pierre Lorange, MD, Master’s candidate in Clinical Sciences 
Université de Montréal 
Funding: 
This research project is funded by the Medtronic Chair in Spinal Trauma of the Université de 
Montréal, managed by Dr. Jean-Marc Mac-Thiong at Hôpital du Sacré-Cœur de Montréal, 
CIUSSS du Nord-de-l’Île-de-Montréal. 
 

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I. Introduction 
Early mobilization is safe and feasible in critically ill patients (1–6), as well as in patients who 
have undergone spinal surgery (7, 8). However, despite strong evidence of the benefits of early 
mobilization after surgery, few patients actually mobilize early (1, 7–9). 
The literature shows that more than 57% of patients of all ages and 83% of patients over 65 years 
old remain in bed for most of their hospital stay (10). In our institution, this prolongs the length 
of hospital stay and reduces the rate of discharge home by 20%. Faced with this harmful and 
reversible epidemic, no sustainable solution has yet been proposed for rapid and effective 
mobilization of patients after spinal surgery. Indeed, the solutions proposed so far involve getting 
the patient out of bed. Thus, a patient without surgical complications still needs an intermediate 
step to help them realize that they are capable of mobilizing independently. In-bed mobilization 
using a bedside cycle, which has already proven effective in critically ill patients (11, 12), 
appears very promising for these patients. However, no study has yet evaluated this approach. 
Our study therefore aims to demonstrate the effectiveness of this mode of mobilization. 
 
II. Problem Statement 
The issue of the mode of patient mobilization has been poorly studied. A few authors have 
examined it without identifying an effective and sustainable solution (8). 
There is no clear consensus regarding the method of mobilization after spinal surgery. To date, 
each center and care team adopts its own approach. Some mobilize patients through 
physiotherapy, while others follow a protocol consisting of a sequence of exercises that the 
patient must perform during hospitalization (6, 8, 13). In our institution, patients after elective 
spinal surgery may mobilize according to their tolerance unless there is a contraindication 
secondary to a surgical complication, such as cerebrospinal fluid leakage or residual instability. 
Limited human resources in physiotherapy mean that patients do not immediately receive 
physiotherapy, and most patients for whom physiotherapy is recommended receive a functional 
assessment and treatment only on postoperative day 2 or 3. The functional assessment 
determines whether the patient can be discharged home or requires intensive functional 
rehabilitation. This entire process often causes delays in mobilization. 
The impact of this delay is significant and harmful. The population undergoing spinal surgery is 
increasingly older (8). These patients are prone to deconditioning related to immobilization and 
associated complications (pneumonia, atelectasis, constipation, venous thrombosis, etc.) (10, 14–
16). It is therefore important to mobilize these patients rapidly during hospitalization using a 
simple and acceptable method in order to reduce length of stay and promote discharge home. 

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Thus, there is a critical need in our center to better structure early mobilization after spinal 
surgery. This would facilitate patient engagement while ensuring safety and modifying staffing 
requirements. In-bed cycling has the potential to meet this need. In other fields, it has already 
demonstrated significant benefits. 
 
III. Literature Review 
The alarm regarding the epidemic of time spent in bed during hospitalization was raised long 
ago. Indeed, alarming statistics show that hospitalized patients spend more than half of their time 
in bed without a specific reason (2, 4). Mudge et al. demonstrated that patients of all categories 
combined (medicine, surgery, oncology) spend 57% of their hospital stay lying in bed and only 
9% standing or walking (16). In elderly patients, this phenomenon is even more pronounced: 
83% of their time is spent in bed and only 3% walking (10). Over 24 hours, these patients spent 
20 hours in bed and only 43 minutes walking. 
These authors highlight barriers to mobilization. In addition to the lack of physiotherapists, they 
agree that the main barriers fall within the “knowledge-to-practice gap,” reflecting insufficient 
knowledge about early mobilization (1, 4). Patients believe that during hospitalization they must 
remain in bed or be mobilized only by physiotherapy (4). In Anekwe et al.’s study, 49% of 
intensive care staff considered early mobilization to be a low priority during hospitalization (1). 
In this Montreal study (1), 63% of nursing staff incorrectly feared that mobilization would lead 
to dislodgement of lines and catheters. 
Pain was presented as a major limiting factor for mobilization (6, 10). However, since the 
introduction of effective postoperative analgesia, patients still do not mobilize more. Early 
mobilization may even provide benefits by reducing long-term pain and opioid use (17, 18). 
In spinal surgery, concerns about the safety and feasibility of early mobilization have been 
refuted by the literature (6–8, 13, 14, 17–21). The risk of accidental removal of lines and 
catheters is reported to be 1% in Leditschke’s study (5). Rupich suggests that it is safe to 
mobilize patients as early as 6 hours postoperatively for spinal surgeries without fusion (6). 
Nielsen et al. introduced a protocol involving 30 minutes of walking within 24 hours 
postoperatively. With this protocol, patients gained confidence in getting up and were able to 
perform daily activities in hospital (getting out of bed, going to the toilet, moving to eat). 
However, large-scale implementation of this protocol is not possible due to physiotherapy 
staffing limitations and patient-related difficulties (17, 21). 
Early mobilization promotes functional maintenance and thus reduces length of hospital stay (8). 
Immobilization promotes deconditioning (losses in biopsychosocial functioning) and 
complications, particularly in older populations (14, 17). Loss of functional capacity related to 
immobilization increases length of stay and the need for intensive physiotherapy care (8). 
According to local statistics developed by the physiotherapy team, 20% of patients assessed 
cannot return home and require intensive acute therapy. In a geriatric population, early 
mobilization after lumbar fusion improves discharge home rates from 64% to 75% (19). Early 

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postoperative mobilization prevents deconditioning and reduces physiotherapy needs (6, 14, 21). 
Thus, the patient becomes more autonomous and mobilizes more frequently. Walking within 24 
hours after surgery has been shown to reduce the incidence of complications such as hematomas 
and surgical site infections (9, 14). However, the full potential of early mobilization to reduce 
length of stay has not yet been achieved due to the lack of an effective and sustainable 
mobilization method. 
In-bed mobilization offers notable potential for mobilizing patients after spinal surgery. Kho’s 
team demonstrated that bedside cycling is feasible and safe in critically ill patients (11) and in 
mechanically ventilated patients (12). This mobilization method does not require moving the 
patient and helps overcome barriers faced by the medical team. For the patient, cycling in bed 
allows them to realize that they are capable of mobilizing independently, unless medically 
contraindicated, and that they do not need to wait for physiotherapy. It provides a reassuring 
intermediate step between bed rest and the demanding task of standing and walking. Although 
this mode of mobilization has existed for several years (22), its effectiveness has not yet been 
demonstrated in patients after elective spinal surgery. 
 
IV. Objectives and Hypotheses 
a. Primary objective 
The primary objective of this study is to demonstrate the effectiveness of early mobilization by 
in-bed cycling on the day after elective spinal surgery. Effectiveness will be reflected by a 
reduction in the time spent in bed compared with patients who do not use the cycle and receive 
standard care. 
b. Hypothesis 
Early mobilization by in-bed cycling reduces the amount of time the patient spends in bed over a 
24-hour period. 
c. Primary outcome 
Early mobilization using in-bed cycling sessions the day after spinal surgery reduces by 1 hour 
and 30 minutes the time patients spend in bed starting on postoperative day 2. In the literature, 
patients spend on average 17 hours out of 24 in bed. In Pedersen’s study, the same patient spent 
1 hour and 30 minutes less time in bed on days when they had full mobility compared with days 
when their mobility was reduced (23). 
a. Secondary objectives 
Secondary objectives are to measure length of hospital stay, kinesiophobia, and mobility in 
patients who completed a cycling session. These outcomes will be compared with patients who 
did not receive cycling sessions. 

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b. Secondary outcomes 
1. Early mobilization by in-bed cycling allows faster discharge home by reducing length of 
hospital stay in days. 
2. Early mobilization by in-bed cycling starting the day after spinal surgery allows faster 
improvement in functional capacity, as measured by validated questionnaires (24) and 
functional tests (25). 
3. Early mobilization by in-bed cycling improves patient participation during physiotherapy 
assessment sessions. This improvement is rated by the therapist using the Pittsburgh 
Rehabilitation Participation Scale. According to Lenze (26), patient participation during 
acute rehabilitation sessions is correlated with the Functional Independence Measure 
score. Participation reflects functional capacity. 
 
V. Methodology 
5.1 Study design 
This project is a prospective, single-blind randomized clinical trial lasting one year. 
Participants meeting inclusion criteria are enrolled and remain in the study until postoperative 
day 2. No follow-up is planned afterward. 
In accordance with the requirements of the International Committee of Medical Journal Editors 
(ICMJE) and to facilitate future publication in peer-reviewed journals, this clinical trial will be 
registered on ClinicalTrials.gov. 
Randomization and data analysis are conducted independently to allow blinded analysis. Due to 
the interventional nature of the study, personnel delivering the intervention are different from 
those analyzing the data to maintain single blinding. The person responsible for data analysis has 
no access to group allocation. 
 
5.2 Sample size 
Based on Pedersen’s study, a patient with reduced mobility spends 17 hours out of 24 in bed. 
When the same patient is independent in basic mobility, this time is reduced by 1.6 hours, 
resulting in 15.4 hours spent in bed. The reported standard deviation for time spent in bed is 
12%, or 2.1 hours (10, 23). Using these data and setting study power at 90%, the minimum 
required sample size is 76 participants. To account for potential exclusions due to postoperative 
complications or post-randomization exclusions, we increased the sample size by 15%. The final 
sample size is therefore 88 participants, divided into two groups (control and intervention) of 44 
participants each. The sample size was calculated using G*Power 3.1.9.2. 
 

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5.3 Study population and eligibility 
The groups will consist of patients in the immediate postoperative period following elective 
spinal surgery who have not experienced complications. 
 
Table 1: Study eligibility and inclusion 
Inclusion criteria 
Female or male aged ≥ 18 years. 
Postoperative day 0 following elective spinal surgery of the decompression type 
with or without fusion, or fusion. 
Patient able to walk independently before surgery (not dependent on another person 
for ambulation and not using a wheelchair). 
Patient admitted directly from the operating room to the ward. 
Hemodynamically stable patient: compared with baseline values or with the 
parameters below: 
o Systolic blood pressure (SBP): ≥ 90 mmHg and < 140 mmHg. 
o Oxygen saturation > 94%. 
o Heart rate (HR): 50–100 bpm. 
Patient cleared for surgery following evaluation by internal medicine in the 
preoperative clinic. 
Alert and conscious patient. 
Valid informed consent obtained from the participant. 
 
Table 2: Exclusion criteria at recruitment and justification 
Exclusion criteria 
Justification 
Non-ambulatory preoperatively. 
The study evaluates mobilization after 
surgery. By design, the participant must be 
independent in walking. 
Body mass index (BMI) > 40 kg/m². 
Morbid obesity is associated with major 
limitations in performing in-bed cycling due 
to ergonomic and positioning issues. It also 
limits hip range of motion. In addition, the 
cycle supports a maximum weight of 100 kg. 

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Spinal trauma with acute neurological deficit. 
Spinal trauma with neurological impairment 
causes spinal instability and motor function 
loss, which prevents mobilization and makes 
the participant non-independent in walking. 
Preoperative non-neurological lower-limb 
impairment: musculoskeletal deformity, 
amputation, hip fracture, severe osteoarthritis 
preventing full joint range of motion, etc. 
In-bed cycling is contraindicated due to 
feasibility concerns. 
Patient with comorbidities assessed by 
internal medicine and not cleared for surgery. 
Special attention is given to the following 
comorbidities: cardiovascular, respiratory, 
diabetes. 
All patients are assessed by internal medicine 
before surgery. If internal medicine 
determines that the patient is unfit for surgery, 
the patient is excluded from the study. 
Criteria for elective surgery are the same as 
for cycling: risks must not outweigh benefits. 
Absence of cardiovascular, respiratory, and 
metabolic instability is required. 
Special attention is given to the following 
comorbidities: 
• 
Cardiovascular: 
o Heart failure 
o Increased cardiovascular event 
risk (myocardial infarction 
[MI], unstable angina, 
arrhythmia, moderate or severe 
aortic stenosis, cerebrovascular 
accident [CVA]) 
o MI, arrhythmia, CVA, acute 
thrombophlebitis, recent 
pulmonary embolism 
o Orthostatic hypotension 
o Arterial hypertension 
o Anemia 
• 
Respiratory: COPD 
Diabetes 
Expected length of stay < 2 days after 
surgery. 
Total participation lasts 2 days; therefore, 
patients with an expected hospital stay of less 
than 2 days are not enrolled. 
 
 
 

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Table 3: Exclusion criteria after recruitment but before randomization 
Exclusion criteria 
Justification 
Surgical complications (e.g., acute 
neurological deficit, dural tear, cerebrospinal 
fluid leak, residual spinal instability). 
Strict bed rest ordered by the care team. 
Concern from the medical team (including the 
research team) regarding imminent 
arrhythmia or myocardial infarction. 
Participation presents excessive potential risk. 
Patient in or transferred through the intensive 
care unit. 
ICU patients have hemodynamic instability or 
frailty, increasing potential risks. 
Hemodynamic instability before the session: 
SBP < 90 mmHg or > 200 mmHg; oxygen 
saturation < 88%; HR < 50 or > 100 bpm; 
temperature > 38 °C. 
If instability persists despite attempts at 
medical stabilization, the patient is excluded 
for safety reasons. 
Capillary blood glucose outside target values: 
< 4.0 or > 7.0 mmol/L fasting or before 
meals; < 5.0 or > 10.0 mmol/L 2 hours after 
meals. 
Participation presents excessive potential risk. 
Patient confused, disoriented, or agitated at 
the time of intervention. 
Invalidates informed consent. 
Patient already evaluated by physiotherapy. 
Physiotherapy determines discharge 
destination and initiates interventions; the 
patient is no longer available for the study. 
Patient in isolation. 
Participation presents excessive potential risk 
and equipment sterilization is difficult. 
Patient already discharged. 
No follow-up is planned; patient is no longer 
available for the study. 
 
Study procedure and assessments 
6.1 Participant recruitment: consent 
Hôpital du Sacré-Cœur de Montréal (HSCM) is a referral center for spinal surgery. With both 
neurosurgical and orthopedic spine teams, an average of 30 patients per month undergo elective 
surgery for spinal conditions. With an acceptance rate of approximately 80%, we aim to recruit 
24 patients per month. 
Patients operated on by Drs. Mac-Thiong, Pelletier-Roy, Laroche, and Khoueir will be 
approached for recruitment after approval by the research ethics and scientific committees. 
Once authorization is obtained from each surgeon, the research team will have access to surgical 
schedules and will identify potentially eligible patients through chart review. 

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Any patient scheduled for spinal surgery (cervical, thoracic, lumbar, or sacral) involving 
decompression with or without fusion, or fusion, with an expected hospitalization longer than 
two days, will be approached preoperatively—either in the preoperative internal medicine clinic 
or during a visit with the surgeon. Patients who walk independently (do not require assistance 
and do not use a wheelchair) are eligible. 
A research team member will present the project, explain the objectives, hypothesis, and 
outcomes. 
After confirming understanding and answering questions, the researcher administers a screening 
questionnaire covering inclusion and exclusion criteria (including cardiovascular comorbidities 
such as severe heart failure, recent myocardial infarction, uncontrolled arrhythmia). If the patient 
meets inclusion criteria, informed consent is obtained. The information and consent form (ICF) 
has been reviewed by the Research Ethics Committee and complies with Good Clinical Practice 
and local regulations. Patients are informed they may withdraw at any time. 
Participants then complete questionnaires assessing walking ability and functional independence 
(Functional Independence Measure [27], SF-36 Quality of Life [28], and SCIM [29]). 
The researcher records sociodemographic data (age, height, weight, ethnicity) and medical 
history. 
 
6.2 Randomization 
A list of participants to be randomized is created after consent is obtained. Immediately after 
surgery, the research staff visit selected participants in their hospital rooms to confirm 
participation and ensure no postoperative exclusion criteria are present. Randomization can then 
proceed, reducing selection bias between groups. 
Randomization occurs the day after surgery and is performed by the study biostatistician, who 
has no contact with participants and does not know their identities. Confidentiality is ensured 
through coding prior to randomization. The key linking participant names to study files is stored 
securely in a locked cabinet and on a secure server. 
Randomization envelopes are generated using a computer-based random number set with a 1:1 
allocation ratio. The allocation formula is as follows: the first participant is randomized to one of 
the two groups; the next participant is assigned to the opposite group. 
On the day of surgery, research staff visit all participants postoperatively to confirm eligibility 
and collect surgical data (baseline pathology, type of surgery, absence of complications, vital 
signs). Each participant receives a Fitbit Inspire HR, to be worn on the left wrist at all times until 
postoperative day 2. 

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On postoperative day 1, kinesiophobia is assessed using the validated Canadian French version 
of the Tampa Scale for Kinesiophobia (TSK-FC). The Five-Repetition Sit-to-Stand Test is 
administered after the cycling intervention. All participants receive standard care at HSCM: 
assisted transfer out of bed into a chair the day after surgery. 
On postoperative day 2, the research staff evaluate all participants (control and intervention 
groups) for: 
1. pain, mobility, and kinesiophobia; 
2. postoperative complications; 
3. removal of the watch. 
This concludes the intervention. 
Physiotherapy functional evaluation is conducted independently of the study and is based on the 
patient’s ability to get out of bed, transfer, and ambulate, determining discharge destination. 
Physiotherapists are blinded to the intervention. 
 
7.1 Control group 
Participants receive the watch and standard care at HSCM. Mobilization over 24 hours is 
assessed on postoperative day 1. Kinesiophobia (TSK-FC) and mobility are assessed on 
postoperative days 1 and 2. 
 
7.2 Intervention group 
The intervention consists of a 30-minute in-bed cycling session on the day following surgery. 
On postoperative day 1, a research team member visits the patient several hours before cycling to 
administer kinesiophobia (Tampa Scale for Kinesiophobia) and pain (VAS) questionnaires. Two 
research staff then conduct the cycling session, ensuring hemodynamic and neurological 
stability. Pain is assessed using the 10-point Visual Analog Scale (VAS), and type and amount of 
analgesics are recorded. The procedure is explained and participants are instructed to report any 
discomfort. 
The head of the bed is elevated to approximately 30°, ensuring ergonomic positioning. A blood 
pressure cuff is placed on the right arm (or opposite the watch), and a pulse oximeter is placed on 
the left hand (or same side as the watch). Capillary glucose is measured in diabetic participants. 
Vital signs (HR, BP, SpO₂) are monitored continuously; BP is recorded at 0, 1, 3, and 5 minutes, 
then every 5 minutes. A trained researcher remains with the participant throughout the session, 
monitoring physiological parameters and comfort. Pain and dyspnea are assessed at 10 and 20 
minutes and as needed. Early stopping criteria allow the session to be stopped at any time. 

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Assistance mode on the ergometer may be used to achieve the target cadence of 40 RPM, which 
corresponds to a walking cadence of approximately 80 steps/min in healthy individuals. 
Participants aim to maintain this speed for 20 minutes, followed by a 5-minute cool-down. Speed 
is visually monitored and adjusted. 
If the participant cannot maintain cadence in active mode, active-assisted mode is used. 
At 30 minutes, vital signs and glucose (if needed) are reassessed, and pain is evaluated. Measures 
are taken if pain is elevated. A 24-hour mobility assessment then begins using the watch. 
Several hours after cycling, mobility is assessed using the Five-Repetition Sit-to-Stand Test, and 
kinesiophobia and pain questionnaires are completed. These assessments are repeated on 
postoperative day 2. 
7.3 Safety parameters 
Stopping criteria are established to allow either the participant or the supervising staff member to 
terminate the session early (11, 22). These criteria are based on previous studies conducted in 
critically ill patients and have been adapted for this study. Monitoring of these parameters is 
carried out in collaboration with the participant. 
• Abnormal vital signs 
• 
Persistent oxygen desaturation < 94% 
o Or a persistent drop in saturation of 4% 
• 
Heart rate > 200 bpm or paradoxically < 40 bpm 
• 
Blood pressure: 
o Increase in systolic blood pressure (SBP) > 20 mmHg or mean arterial pressure 
(MAP) > 110 mmHg 
o Or decrease in SBP > 20 mmHg (suggestive of cardiac failure) 
• Pain reported by the participant or discomfort. Signs and symptoms of exercise intolerance 
• 
Modified Borg scale > 8 
• 
Chest, epigastric, back, or arm pain: angina 
• 
Shortness of breath or dyspnea disproportionate to the level of effort 
o At any time, if the patient reports shortness of breath causing them to slow down, 
motor assistance will be increased until dyspnea resolves 
o If shortness of breath persists, the session will be terminated 
• 
Severe joint pain 
• 
Dizziness and vertigo: pallor, cyanosis, nausea, sudden sweating, fatigue, leg cramps 
• 
Palpitations 
• 
Headache 

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• Patient becomes agitated during the session 
• Dislodgement of equipment: cycle, board, catheter 
• Request by the participant to stop 
 
7.4 Equipment and storage 
A smartwatch with integrated pedometer and accelerometer (“Fitbit Inspire HR fitness trackers” 
or “Fitbit Inspire 2 fitness trackers”) with heart rate monitoring will be assigned to each 
participant to track mobilization. 
This watch specifically measures the number of steps over 24 hours, distance traveled, calories 
burned, total activity time, sleep time, time spent lying in bed, etc. It distinguishes time spent 
stationary from time spent walking. Regarding vital signs, it provides heart rate data. 
Four watches will be used for the project. They will be stored in our facilities in room C2080. 
The removable wristband and the watch face will be cleaned before and after each use with the 
same disinfecting agents used in the operating room between cases for sterilizing equipment such 
as operating tables. 
The watch has a data storage capacity of seven days. After retrieval, it will be connected to a 
compatible computer to download the data. Data collected by the watch before, during, and after 
the intervention will be stored in three separate files. 
• 
Data before the intervention will be used to verify hemodynamic stability and will be 
correlated with nursing vital signs; these data will not be used for analysis. 
• 
Data related to the intervention are collected to ensure hemodynamic stability and are not 
part of the primary outcome analysis. They are stored separately to maintain blinding 
during data analysis. 
 
In-bed leg cycling consists of daily 30-minute sessions using an SF-B0717 ergometer or an 
APT5 ergometer. Since both devices have identical measurement parameters, they may be used 
simultaneously to provide cycling sessions for all enrolled patients and to avoid interruptions due 
to equipment failure. 

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A portable ergometer (SF-B0717 Electric Surface Cycle 90 or APT5) will be used for in-bed 
cycling. This device allows different pedaling modes according to participant ability: 
• 
Active-assisted mode: pedaling assisted by the motor 
• 
Active mode: pedaling entirely driven by the participant 
The motorized ergometer has 12 speed levels ranging from 30 to 90 RPM (in increments of 5). A 
remote control allows adjustment of direction, speed, and start of the device. It includes a timer 
for time tracking. The maximum supported weight is 100 kg. 
 
To install the ergometer in bed, an adjustable table for tabletop ergometers (model ERP7957-01) 
will be used. This table can be adjusted according to participant height and bed height to achieve 
a 30° head-of-bed angle and appropriate ergonomic positioning. The cycle and table will be 
stored in room C2080. 
 
 
A motorized portable ergometer (APT5 Active Passive Trainer on Hi-Low Stand, 
ORTHOCANADA) will also be used. The APT5 can be adjusted in length and includes an 
adjustable crank and leg support to ensure stability and proper alignment of the lower limbs 
during pedaling. 
The system includes a display screen showing cycling parameters such as cadence and power 
output. The APT5 screen is used to program cycling mode, cadence, time, power, and speed 
level. As with the SF-B0717, three cycling modes are available: 
• 
Passive (motor-driven without patient initiation) 
• 
Active-assisted (partially initiated by the patient with motor assistance) 
• 
Active (fully initiated by the patient) 
Cycling mode and motor speed can be adjusted to achieve the desired cadence. 
When not in use, the system will be stored in the physical department of our institution. 

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Before and after each use, the pedaling devices and the SF-B0717 support will be sterilized using 
the same disinfecting agents used in the operating room between cases for equipment such as 
operating tables. 
For monitoring vital signs, a blood pressure cuff and a digital pulse oximeter will be placed on 
the participant during the intervention. 
 
VIII. Data collection and analysis 
Confidentiality is ensured for all participants through a coding system. Each participant will 
receive a code. The key linking the participant’s name to the research file will be kept in a locked 
cabinet and on a secure server. 
For both primary and secondary outcomes, data are collected before and after the intervention. 
Data collection and storage will be performed using Excel. 
The main document will contain all data required for analysis of the primary outcome, except 
those identifying group allocation, i.e., all data collected during the intervention (questionnaire 
and test scores, vital signs, VAS scores). These will be stored in a separate file. 
 
8.1 Data collected 

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Before the intervention, at the time of consent, the research staff administer a questionnaire on 
walking ability and functional independence (Functional Independence Measure [FIM], SCIM, 
and SF-36). Modified versions of the FIM, SCIM, and SF-36 are used for study purposes. 
• 
With the modified SF-36 (“limitations in activities” section), limitations in activities of 
daily living (ADLs) are assessed. 
• 
With the modified FIM (“locomotion” and “transfers” sections), locomotion and transfer 
abilities in ADLs are specifically evaluated. 
• 
With the modified SCIM (“Mobility indoors and outdoors on level surfaces” section), the 
level of assistance required for ambulation is specifically assessed. 
These measures will be used in data analysis, as baseline performance is expected to influence 
the primary outcome (time spent out of bed). The researcher also collects sociodemographic data 
(age, height, weight, ethnicity) and medical history. 
If the participant cannot maintain the target speed of 40 RPM, they may continue the intervention 
at a lower comfortable speed. This will be recorded and taken into account in data analysis. The 
same applies to pedaling duration. 
 
Table A: Baseline characteristics of the study population 
 
Variable 
Type of categorization 
ID 
Last name 
 
First name 
 
Medical record number 
 
Date of birth 
 
Identification code 
 
Sociodemographic 
Age 
Continuous 
Sex 
Dichotomous 
Marital status 
Categorical 
Race 
Categorical 
Weight 
Continuous 
Height 
Continuous 
BMI 
Continuous 
Comorbidities 
 
Will be recorded 
Surgery-related data 
Underlying pathology 
Will be recorded 
Type of surgery 
Categorical 
Date of surgery 
Continuous 
Complications 
Will be recorded 
Surgical team (neurosurgery vs 
orthopedics) 
Dichotomous 
Analgesia (type) 
 
Analgesia 
(amount 
taken 
before the intervention) 
 

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Analgesia (amount taken after 
the intervention, assessed on 
POD#2) 
 
 
Table B: Primary outcomes 
 
Variable 
Type of categorization 
Mobility 
Basic mobility (1: without 
assistance, 2: with assistance, 
specify, 3: non-ambulatory) 
Categorical 
FIM score 
Continuous 
SF-36 score 
Continuous 
SCIM score 
Continuous 
Tampa Scale for Kinesiophobia 
score (TSK-FC) 
Continuous 
Time for five repetitions of sit-
to-stand 
Continuous 
Intervention-related 
data 
Group allocation 
 
Pain level (immediately before, 
during, and immediately after) 
Dichotomous 
Vital signs before, during, and 
after intervention (HR, BP, 
SpO₂) 
Continuous 
Fitbit data over 24 
hours 
Active minutes 
Continuous 
Walking time 
 
Number of steps 
Continuous 
Calories burned 
Continuous 
Sleep time 
Continuous 
Time spent in bed 
Continuous 
 
Table C: Secondary outcomes 
 
 
Variable 
Type of categorization 
Hospitalization-
related data 
Patient 
out 
of 
bed 
on 
postoperative day 1 
Dichotomous 
Hospitalization-related 
complications 
Will be recorded 
Length of hospital stay 
Continuous 
Discharge 
destination 
(inpatient rehabilitation unit 
[URFI] vs home discharge 
[RAD]) 
Dichotomous 
Pittsburgh 
Rehabilitation 
Participation 
Scale 
score 
 
Categorical 

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8.2 Statistical analysis plan and data analysis 
All statistical analyses will be performed by a statistician blinded to participant identity and 
group allocation. The statistician will have no contact with participants. 
No loss to follow-up is expected, as there is no follow-up period. In the event of premature 
termination, data collected prior to withdrawal will be used, and mobilization will be assessed 
over the subsequent 24 hours. Statistical power to detect a statistically significant difference is 
set at 80%, with a type I error rate (alpha) of 0.05. 
 
8.2.1 Primary outcome analysis 
Data will be analyzed and reported according to the intention-to-treat principle. In addition to 
descriptive statistics, comparisons between the intervention and control cohorts will be 
performed using Student’s t-test. Given that randomization is expected to reduce confounding, 
we do not anticipate adjusting for other potential confounders (age, sex, type of surgery) in the 
primary analysis. However, baseline characteristics between the intervention and control groups 
will be compared using multivariate analysis, and adjustments will be made for any confounders 
that differ substantially between groups. 
The primary outcome is defined as the amount of time the participant spends out of bed. These 
data will be obtained from the smartwatch. 
 
8.2.2 Interim analysis 
A micro-analysis of the data will be conducted after the inclusion of 30 participants (15 per 
group). The objective of this interim analysis is to assess the safety of the intervention. Early 
mobilization following spinal surgery has been shown to be safe in the literature. Similarly, the 
use of in-bed cycling has been demonstrated to be safe in mechanically ventilated ICU patients 
receiving vasopressors. However, no study to date has evaluated the use of in-bed cycling as a 
mobilization strategy following spinal surgery, which highlights the innovative nature of this 
project. This interim analysis will also allow for reassessment of the study objectives. 
 
8.2.3 Secondary outcome analysis 
To determine the impact of mobilization on hospitalization and functional capacity, three 
secondary outcomes have been defined. 
The first evaluates the effect of early mobilization through in-bed cycling on length of hospital 
stay. 

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The second evaluates patient mobility using the five-times sit-to-stand test and the TSK-FC 
questionnaire. 
The third evaluates the effect of the intervention on patient participation in physiotherapy 
assessment sessions. This outcome is measured using the Pittsburgh Rehabilitation Participation 
Scale. This scale has been validated in the literature and is correlated with the Functional 
Independence Measure (FIM). It has been shown to reflect patients’ functional capacity. 
All secondary outcome analyses will be performed using Student’s t-test. 
 
IX. Ethical considerations 
Following approval by the Research Ethics Committee, all patients scheduled for spinal surgery 
will be approached preoperatively, either during their preoperative visit with the physician or on 
the day of surgery, in order to obtain informed consent. After providing free and informed 
consent, each patient will be randomized to one of the study groups. 
Participants are free to withdraw their consent at any time during the study. Prior to the 
intervention, they may choose not to complete the cycling session. After the session, they may 
request that their data be withdrawn from the study. 
 
X. Relevance and expected impact 
Hospitalization-related costs are substantial. At our institution, the cost of one day of 
hospitalization is approximately CAD $3,267, excluding professional fees. According to the 
literature, a simple early mobilization intervention may reduce these costs by decreasing length 
of stay and complications related to deconditioning. An increase in the amount of time patients 
spend out of bed reflects improved functional capacity. Physiotherapy assessments will therefore 
more frequently and earlier identify patients as suitable for discharge home. 
With the introduction of in-bed cycling sessions beginning the day after elective spinal surgery, a 
reduction in length of hospital stay and associated costs is expected. 
The quality and simplicity of the mobilization protocol will reduce the human resources required 
for patient mobilization. In neurologically intact patients, only a single nursing staff member will 
be required for supervision. This approach also helps address physiotherapist workforce 
shortages. 
In-bed cycling provides significant potential benefits for patients. Early mobilization has been 
associated with increased patient satisfaction with hospitalization. 
 

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XI. Dissemination of results 
Study results will be disseminated through publications accessible to the general public. 
Participants in the study will also be given the opportunity to consult these articles after 
publication. 
 
XII. Timeline 
Study duration: 2 year 
Initial protocol: 
• 
Review by the Research Ethics Committee (REC): December 2019 – April 2020 
• 
Approval by the REC and Scientific Committee: April 2020 
• 
Participant recruitment, randomization, and intervention: April–June 2020 
• 
Statistical analysis: June–July 2020 
• 
Dissemination of results: August 2020 
• 
Submission for peer review: September 2020 
After protocol modification: 
• 
Approval by the REC and Scientific Committee: February 2026 
• 
Participant recruitment, randomization, and intervention: March–August 2028 
• 
Statistical analysis: August 2028 
• 
Dissemination of results: January 2029  
• 
Submission for peer review: January 2029 
 
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