Comparison of Clinical Outcomes, Complications Rate and Treatment Costs of Mini-TLIF and MIDLIF in the Treatment of Discogenic Low Back Pain

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.

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.

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.

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).

The European Quality of Life - 5 Dimensions, 5 Levels (EQ-5D-5L) is a standardized, self-reported instrument developed by the EuroQol Group to measure health-related quality of life (HRQoL) across a wide range of populations and conditions. It comprises two main components: a descriptive system with five health dimensions (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), each rated on five levels of severity.

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.

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.

Measurement of the length of stay (LOS) in the hospital.

Evaluation of the operating room time (OR time) required for the surgery.

Quantification of estimated blood loss (EBL) during the surgical procedure.

Evaluation of intervertebral space height (ISH), foraminal height (FH), radiological evidence of bone fusion, and global and segmental lordosis of the lumbar-sacral spine.

Measurement of the duration required for working patients to resume professional activities.

Evaluation of the occurrence of adjacent segment disease based on MRI of the lumbar-sacral spine.