Background
Degenerative disc disease (DDD) is the leading cause of lower back pain and disability, which prevalence increasing with age. When conservative treatment fails, surgical methods of spinal fusion are employed. Minimally invasive techniques, including minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and midline lumbar interbody fusion (MIDLIF), have well-documented advantages over traditional open transforaminal interbody fusion (open-TLIF). However, data comparing these two minimally invasive methods in treating DDD are minimal and sometimes contradictory. I am running a few minutes late; my previous meeting is running over.
Methods This is a prospective, randomized, partially blinded, two-arm trial aiming to compare the outcomes, complications, and treatment costs of MIS-TLIF and MIDLIF in patients with discogenic low back pain. A total of 100 adult patients with lumbosacral spine pain and radicular symptoms, unresponsive to conservative treatment for over one year, will be enrolled. Patients will be randomized (1:1) into two arms: MIS-TLIF (control, n=50) and MIDLIF (intervention, n=50), with a 12-month follow-up. Inclusion criteria include age ≥18 years and discopathy at one or two levels requiring interbody stabilization. Exclusion criteria include multilevel pathology, spinal deformities, and pain causes other than degenerative disease. Primary endpoints assess pain (VAS, NRS scales), disability (COMI, ODI questionnaires), and quality of life (EQ-5D-5L questionnaire) at 1, 3, 6, and 12 months post-surgery. Secondary endpoints include complication rates (nerve root damage, infections), costs (hospitalization, implants), length of hospital stay, procedure duration, blood loss, morphometric parameters (intervertebral space height), and adjacent segment disease based on imaging studies (MRI, CT, X-ray). Data analysis uses parametric/non-parametric tests (e.g., t-test, Mann-Whitney) in the R software. The trial adheres to the Helsinki Declaration, with ethics approval (no. 112/2024).
Discussion Data on the comparison of MIDLIF and MIS-TLIF in treating DDD are minimal and inconsistent. Some reports have advantaged MIDLIF in shorter operative time, decreased intraoperative blood loss, and reduced hospital stays, while others favor MIS-TLIF. This trial addresses these gaps by providing high-quality evidence on clinical superiority, cost-effectiveness, and long-term outcomes compering MIDLIF and MIS-TLIF. There is a high need for a high-quality, prospective study to examine this problem.
Discogenic lower lumbar-sacral pain lasting longer than one year
Failure of conservative treatment, including rehabilitation and pain management
Lumbar discopathy qualified for interbody fusion and pedicle screw stabilization
Informed consent of the patient for the study and proposed treatment
Contraindications to surgery under general anesthesia
Age < 18 years
Pregnancy, breastfeeding
Lack of informed consent to participate in the study
Parallel
Midline Lumbar Interbody Fusion (MIDLIF)
Procedure/SurgeryMidline Lumbar Interbody Fusion (MIDLIF) is a procedure utilizes a medial approach to the spine, involving the retraction of the segmental back muscles to expose the lamine and articular processes. Screw placement is medialized, with entry to a point along the pars intercularis or joint surface. It places the screw through potentially more cortical and stronger bone. Decompression is achieved by resecting the inferior articular process and lamina marginalis, followed by a discectomy. Subsequently, a transforaminal lumbar interbody fusion (TLIF) is performed to place an interbody cage and promote fusion.
Minimally Invasive Transforaminal Lumbar Interbody Fusion (mini-TLIF)
Procedure/SurgeryMinimally invasive Transforaminal Lumbar Interbody Fusion (mini-TLIF) is a procedure that employs a percutaneous approach for pedicle screw placement through the pedicles. Decompression is performed using a lateral approach, with 2-3 cm lateral to the ipsilateral borders. This is followed by resection of the inferior articular process and removal of the ligamentum flavum, facilitating discectomy. An interbody cage is then inserted to achieve fusion.
Visual Analog Scale (VAS)
The Visual Analog Scale (VAS) is a measurement tool designed to quantify subjective pain intensity. It consists of a straight horizontal line, typically 10 cm (100 mm) long, with two endpoints anchored by descriptive labels ("no pain" on the left and "worst imaginable pain" on the right). Respondents mark a point on the line that best represents their perception, and the score is determined by measuring the distance in millimeters from the left endpoint to the mark, yielding a continuous score from 0 to 100.
Numeric Rating Scale (NRS)
The Numeric Rating Scale (NRS) is a unidimensional, self-reported psychometric tool primarily used to quantify the intensity of pain on a numerical scale. It typically consists of an 11-point scale ranging from 0 to 10, where 0 represents "no pain" (or no symptom) and 10 represents "worst possible pain" (or maximum intensity imaginable). Respondents verbally or in writing select a whole number that best reflects their current experience, making it a discrete rather than continuous measure.
Core Outcome Measures Index
The Core Outcome Measures Index (COMI) is a multidimensional, patient-reported outcome measure designed to assess the key domains affected by spinal disorders, particularly low back pain and related conditions. It consists of a brief questionnaire (typically 7-8 items) that evaluates pain intensity, function, symptom-specific well-being, general quality of life, and disability (both social and work-related). Responses are scored on a 0-10 scale, where higher scores indicate worse outcomes; the overall COMI score is the average of the domain scores, providing a single summary index.
Oswestry Disability Index (ODI)
The Oswestry Disability Index (ODI) is a self-reported questionnaire designed to quantify the level of functional disability associated with low back pain and related spinal conditions. It consists of 10 sections, each addressing a specific aspect of daily life impacted by pain: pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sex life (optional in some versions), social life, and traveling. Each section has 6 statements scored from 0 (no limitation) to 5 (maximum limitation), with the total score expressed as a percentage (0-100%), where higher scores indicate greater disability. Common interpretations include 0-20% (minimal disability), 21-40% (moderate), 41-60% (severe), 61-80% (crippled), and 81-100% (bed-bound or exaggerating symptoms).
Complication Rates and Types
Evaluation of the frequency and nature of complications between groups, including nerve root damage, cerebrospinal fluid leak, instrumentation failure, postoperative wound infection, and other adverse events.
Direct Treatment Costs
Analysis of direct treatment costs with a breakdown by category, including total hospitalization costs, costs of implants used, costs of medications administered, and costs of the surgical procedure.
Hospitalization Duration
Measurement of the length of stay (LOS) in the hospital.
Procedure Duration
Evaluation of the operating room time (OR time) required for the surgery.
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