Effects of Muscle Energy Technique combined with Sciatic Nerve Mobilization for sciatica in patients with chronic lumbar disc herniation

This is a three-arm, parallel-group, randomized controlled trial. Participants in all three groups will receive their respective interventions three times per week for four consecutive weeks (total of 12 sessions). All interventions will be delivered at the same clinical setting. The specific interventions for each arm are described below. All physiotherapy interventions will be delivered by a single licensed physiotherapist with over 5 years of clinical experience in musculoskeletal rehabilitation. Prior to the trial, the therapist will complete standardized training on the study protocol to ensure consistent delivery of all techniques across all participants and groups. To control for detection bias, all outcome assessments (VAS, ODI, SF-36) will be performed by an independent assessor who is not involved in any treatment procedure and is blinded to group allocation. Participants will be instructed not to disclose their group assignment to the assessor during subsequent assessments. Due to the nature of the physical intervention, blinding of the treating physiotherapist and participants is not feasible; therefore, assessor blinding will be employed, and the treating therapist will not be involved in any outcome measurement procedures. Treatment fidelity and adherence across all groups will be monitored through session attendance checklists, therapist documentation of participant tolerance and subjective responses during each visit, and recording of any protocol deviations or adjustments made. 1. Arm 1 - Experimental Group (MET + SNM + Conventional Treatment) Participants in this arm will receive a combination of Muscle Energy Technique (MET), Sciatic Nerve Mobilization (SNM), and conventional treatment (TENS and Cat-Camel exercise). 1.1 Muscle Energy Technique (MET): MET is primarily applied to the erector spinae and quadratus lumborum muscles, following a standardized protocol of isometric contraction—relaxation—to a new resistance barrier. Contraction intensity is controlled at approximately 20%–30% of maximum voluntary contraction force to ensure the procedure remains gentle and safe. 1.1.1 Quadratus Lumborum MET : The quadratus lumbosum energy technique is performed in the supine position to ensure pelvic stability and reduce compensatory movements of the trunk, thereby enhancing the controllability and repeatability of this technique. The subject was supine with both lower limbs naturally extended, the pelvis in a neutral position, and the therapist standing next to the knee joint on the healthy side. First, the healthy leg is flexed and the foot is placed on the outside of the affected leg, the therapist grasps the area above the ankle joint with the hand closest to the affected side ankle and gently pulls the affected leg in a direction toward the healthy side (keeping the knee straight). This results in a mild stretching sensation and pelvic drop of the quadratus lumborum on the affected side, which begins to stretch the quadratus lumborum and gradually establishes an initial resistance barrier. At the same time, the therapist's other hand was placed above the ilium on the affected side to stabilize the pelvis and prevent pelvic rotation or compensatory trunk movements. The initial resistance barrier was considered to have been reached when the therapist perceived mild resistance in tissue tension without causing pain or significant discomfort to the patient. After establishing a resistance barrier, the therapist instructed the patient to perform mild isometric contractions. The patient is asked to attempt to elevate the pelvis toward the head on the affected side (i.e., perform a "hip lift" -like exercise), the hand of the therapist placed on the ilium on the affected side provides resistance and stabilizes the pelvis, which essentially constitutes an isometric contraction of the quadratus lumborum on the affected side in the coronal plane. The isometric contraction intensity was controlled at about 20% to 30% of the maximum voluntary contraction force for about 10 seconds. Subsequently, the therapist instructed the patient to relax completely. During the relaxation phase, the therapist gradually increased the stretch of the affected lower limb to the healthy side, inducing a further mild sink of the affected pelvis into a new range of motion until a new barrier of tissue resistance was encountered. Throughout the procedure, traction and isometric contractions must be maintained within comfortable physiological limits, avoiding forced end traction or triggering painful responses. This sequence of isometric contraction, relaxation, and re-establishment of the resistance barrier was repeated in a single treatment, for a total of five cycles, or until there was a condition that required cessation, such as muscle fatigue, fluctuations in symptoms, or patient discomfort. 1.1.2 Erector Spinae MET : Erector spinae energy techniques were performed using standardized positions and procedures. The subject was placed in a lateral position with the affected hip directly above the healthy side, the hip and knee flexion 90 degrees, a pillow placed between the knees to stabilize the pelvis, and the therapist standing in front of the subject to control the lumbar segments. At the beginning of treatment, the therapist slowly guides the patient's trunk into a mildly flexion position to stretch the erector spinalis on the affected side and establish an initial resistance barrier, a position determined by mild resistance that does not cause pain. Subsequently, subjects were instructed to perform isometric contractions in the opposite direction of the stretch, with the therapist placing one hand at the sacrum and one hand between the bilateral scapula, providing isometric counterforce resistance and preventing visible trunk movement. Isometric contraction intensity was controlled at about 20% to 30% of the maximum voluntary contraction force for 10 seconds. After the contraction ended, the subject fully relaxed and the therapist passively slowly guided the trunk into a new range of motion without causing pain or forcing stretch until a new resistance barrier was encountered. This sequence of isometric contraction, relaxation, and re-establishment of the resistance barrier was repeated in a single treatment, for a total of five cycles, or until there was a condition that required cessation, such as muscle fatigue, fluctuations in symptoms, or patient discomfort. The exercise completed throughout the intervention consists of the participant performing the prescribed isometric contractions against manual force, followed by complete relaxation, while the therapist passively moves the muscle into a new range—this sequence itself constitutes the core exercise cycle, no additional exercises are performed during the MET component. Adherence to MET is monitored through attendance checklists, therapist documentation of contraction quality and fatigue, participant tolerance recording, and the number of complete contraction-relaxation cycles achieved per session. 1.2 Sciatic nerve mobilization (SNM): Sciatic nerve mobilization employs the tensioner technique along the Straight Leg Raise (SLR) pathway as a standardized within the present study implementation method, the specific angles, holding time, and repetition parameters were determined based on clinical feasibility and participant tolerance, and were applied uniformly across all sessions to ensure procedural consistency. The subject lies supine with both lower limbs naturally extended and the pelvis maintained in a neutral position. The therapist stands on the affected side, slowly flexing the affected hip joint to approximately 60–70°, from this position, the therapist progressively extends the knee joint while simultaneously applying ankle dorsiflexion, this action increases both proximal and distal tension along the sciatic nerve pathway. Throughout the procedure, emphasis is placed on maintaining continuous movement and rhythmic control. Hold the end position for approximately 10 seconds, then slowly return to the starting position, each treatment session consists of 2 sets, with 10 repetitions per set, allowing approximately 10–15 seconds of relaxation time between repetitions. All movements are controlled within a range that does not induce or significantly exacerbate neuropathic symptoms such as radiation pain or numbness, if symptoms worsen, adjustments are made by reducing the ankle dorsiflexion angle or decreasing the knee extension range. Adherence to SNM is monitored through attendance checklists, therapist documentation of participant tolerance, and recording of any adjustments made. 1.3 Conventional Treatment: This consists of TENS and Cat-Camel exercise. Adherence to conventional treatment is monitored through attendance checklists, documentation of TENS parameters, and recording of exercise completion. 2. Arm 2 - Comparator Group (SNM + Conventional Treatment) Participants in this arm will receive exactly the same Sciatic Nerve Mobilization (SNM) and Conventional Treatment protocol as described in Arm 1 (SNM + TENS + Cat-Camel exercise). The same adherence monitoring procedures apply. 3. Arm 3 - Conventional (Control) Group This group receives conventional treatment alone.