The Effect of Quadratus Lumborum (QL) Block on the Incidence of Chronic Neuropathic Pain After Retroperitoneal Laparoscopic Donor Nephrectomy: A Study on Neuroinflammation and Neurophysiology

Neuropathic Pain Incidence: Neuropathic Pain in 4 Questionnaire

Pain that develops after a surgical procedure in the area of surgery and its radiation, persists for at least 3 months after surgery, other causes of pain (e.g. infection and history of malignancy) or pre-existing pain have been excluded. Total score: 10 Score ≤ 4 = no pain developed Score ≥ 4 = pain developed

Time frame: 3 months after intervention

Neuromodulation Parameter: Degree of functional interference using Behavioral Pain Interference (BPI)

The degree of pain that develops after a surgical procedure in the area of surgery and its radiation, persisting for at least 3 months after surgery, other causes of pain (eg infection and history of malignancy) or pre-existing pain have been excluded. Behavioral Pain Interference (BPI) questionnaire based on the average of questions 4, 5, and 6 1. Mild (NRS 1-3) 2. Moderate (NRS 4-6) 3. Severe (NRS 7-10)

Time frame: At 3 months after intervention

Chronic Pain Severity: Leeds Assesment of neuropathic symptoms and sign (LANSS) scale

A measuring tool used to assess neuropathic pain and provides information to differentiate nociceptive pain from neuropathic pain. Total score: 24 \<12: Not neuropathic \>12: Neuropathic pain

Time frame: At 3 months after intervention

Neuroinflammation Parameter: Serum Concentration of Toll-like Receptor 4 (TLR4)

Transmembrane receptors in the innate immune system. Units: ng/mL

Time frame: At 3 months after intervention

Neuroinflammation Parameter: Serum Concentration of Calcitonin gene-related peptide (CGRP)

Neuropeptides that play a role in pain transmission and vasodilation Unit: pg/mL

Time frame: At 3 months after intervention

Neuroinflammation Parameter: Serum Concentration of Nerve Growth Factor (NGF)

Neurotrophic factors that play a role in promoting the growth and survival of sensory neurons Unit: pg/mL

Time frame: At 3 months after intervention

Neurophysiology Parameter: Mechanical Detection Threshold (MDt)

Measures the minimum force needed for a person to perceive a light mechanical stimulus, tested using von Frey filaments. Skin contact test for 2 seconds using 1 set of von Frey filaments. The examination is performed in m. trapezius. Unit: mN Lower result means: higher sensitivity (normal or hypersensitivity) Higher result means: Reduced sensitivity, could indicate hypoesthesia or nerve damage

Time frame: At 3 months after intervention

Neurophysiology: Mechanical Pain Threshold (MPt)

Accurate measurement of pain threshold. Skin contact test using repeated pinpricks at the same location. Comparative assessment of initial pain scale with pain scale after repeated stimulation. Examination is performed at m. trapezius. Unit: Numerical Rating Scale (NRS) from 1 to 10 Lower NRS: higher sensitivity to pain Higher NRS: lower sensitivity to pain

Time frame: At 3 months after intervention

Neurophysiology Parameter: Pressure Pain Threshold (PPt)

Pain tolerance examination. Pressure assessment in kgf/cm2 units where the patient complains of pain according to the stimulus given. The examination is carried out in m. trapezius Units: kgf/cm2. Lower PPT: Increased pain sensitivity Higher PPT: Decreased pain sensitivity

Time frame: At 3 months after intervention

Neurophysiology Parameter: Mechanical Temporal Summation of Pain (MTSP)

Evaluates central sensitization by applying repeated light mechanical stimuli and rating how pain builds up over time. Pressure assessment in kgf/cm2 units where the patient complains of pain according to the stimulus given. The examination is carried out in m. trapezius. Units: Verbal Numeric Scale (VNS) from 1 to 10 Higher MTSP score: Indicates central sensitization Lower MTSP score: Normal pain processing

Time frame: At 3 months after intervention

Neuromodulation Parameter: Serum Concentration of beta-Endorfin

Neuropeptide produced in the anterior pituitary and brain, as an endogenous opioid. Units: pg/mL

Time frame: At 3 months after intervention