Comparison of clinical and radiological outcomes between two methods of using cortical screws and pedicle screws in multilevel lumbar spine fusion surgery at Imam Khomeini Hospital, Tehran

Overall objective: To compare clinical (VAS, ODI) and radiological outcomes (fusion rate, screw loosening, facet joint damage) between the two methods of using cortical screws (CBT) and pedicle screws (PS) in multilevel lumbar spine fusion surgery

A controlled clinical trial with parallel groups, single-blind, randomized, on 102 patients. The rand function of Excel software was used for randomization.

This study will be a prospective, randomized clinical trial that will be conducted in the Neurosurgery Department of Imam Khomeini Hospital, Tehran, in 2025-2026. Diagnosis will be based on lumbar spine radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) in conjunction with clinical symptoms and physical examinations. Patients will be followed up for one year after surgery.

Patients from the Neurosurgery Department of Imam Khomeini Hospital, Tehran with the following inclusion criteria: Inclusion criteria: Male and female patients 18 years of age and older, patients with lumbar disease who are candidates for two- to four-level fusion surgery and have not responded to treatment for 3 months؛ Exclusion criteria: Patients with osteoporosis, patients with involvement of less than two levels of the lumbar spine or more than four levels, history of lumbar fusion surgery.

All surgeries will be performed using the same surgical technique. It will be performed through a posterior midline incision. In the CBT group, a bilateral screw-rod system with cortical track screws will be used under fluoroscopic guidance. In the PS group, a bilateral screw-rod system with conventional pedicle screws will be used.

Radiographic outcomes included facet joint damage (FJV) rate, screw placement accuracy, fusion rate, and screw loosening.

Patients will be assessed for eligibility and, after obtaining written informed consent and basic information, will be randomly assigned to either Group A (PS screw) or Group B (CS screw). The patient will be blinded to the group assignment, but the surgeon and the medical staff will not be blinded; therefore, the study will be considered a single-blind study. Randomization will be performed using a block randomization approach. A detailed, step-by-step procedure for performing block randomization for a clinical trial with 102 patients in two groups of 51 is presented: Objective: To randomly assign 102 patients to two equal groups (CBT screw group and pedicle screw group) in such a way that a relative balance between the number of participants in each group is maintained at each stage of patient recruitment. 1. Design specifications Total number of participants: 102 Number of groups: 2 groups (CBT and Pedicle) Allocation ratio: 1:1 Randomization method: Block randomization with variable block size 2. Block size selection To maintain balance while avoiding prediction of allocation, variable block sizes (e.g., 4 and 6) are used: Block 4: includes 2 people in the CBT group and 2 people in the Pedicle group Block 6: includes 3 people in the CBT group and 3 people in the Pedicle group Number of blocks required: Assuming a combination of blocks 4 and 6, to reach 102 people, the total block size must be 102 (12 blocks of 6 people and 3 blocks of 4 people = 102). 3. Generation of random allocation sequences Using the site https://www.sealedenvelope.com/simple-randomiser/v1/lists and Excel, the output of the following steps will be performed: For each block, all possible combinations of symmetric allocation (CBT–Pedicle–CBT–Pedicle) are listed. Using the RAND function in Excel, a random selection is made from these combinations. This is repeated until the total number of subjects is 102. 4. Allocation Concealment The results of the generated random sequence are placed in numbered and sealed envelopes. Each envelope contains a sheet with the name of the allocation group. Only the researcher responsible for allocation (and preferably not involved in the outcome assessment) opens the envelope when the patient enters the study. 5. Allocation Implementation After confirming the inclusion criteria and obtaining informed consent from the patient, the patient is allocated to one of the two groups based on the envelope number (e.g., in order of arrival). The patient’s name, envelope number, and allocation group are entered in the data recording form. 6. Practical example for a block of 4: The same logic is followed for subsequent blocks. To reduce bias in outcome measurement, a consultant radiologist and a consultant neurosurgeon will independently review the radiographs and CT scans of each patient, and disagreements will be resolved by discussion.

The patient is blinded to the group allocation, but the surgeon and the treatment staff are not; therefore, the study is considered single-blind. The randomly generated sequence is placed in numbered, sealed envelopes. Each envelope contains a slip of paper with the name of the allocation group. Only the investigator responsible for allocation (and preferably not involved in the outcome assessment) opens the envelope when the patient enters the study.

A thesis and an article of the results of statistical analysis and its discussion

After defending the thesis and publishing the article

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To the Tehran Medical Sciences Research Associate website after registering the thesis or the journal in which it is published.

To the Tehran Medical Sciences Research Associate website after registering the thesis or the journal in which it is published.