The current work compared the effectiveness of slider and tensioner neurodynamic mobilization techniques and stretching exercises on pain, function, and ROM of patients with chronic discogenic sciatica. The main finding of this clinical trial is that slider and tensioner neurodynamic mobilization techniques were more effective compared to stretching exercises in reducing pain, increasing hip flexion, knee extension and lumbar flexion ROM, and improving functional disability. Furthermore, it was founded that the slider technique had a greater effect as compared to the tensioner technique regarding ROM and succeeded to improve mobility of hip flexion, knee extension, and lumbar flexion.
This study results supported the effectiveness of neurodynamic mobilization in the management of discogenic sciatica concerning pain alleviation and sciatic nerve mobility restoration. After nerve root compression, the nerve induces oedema and hypoxia which compromise microcirculation. Neurodynamic mobilization techniques associated with short, sustained movements was effective to reduce oedema and alleviate hypoxia which further reduced the associated symptoms and dysfunctions (15).
Slider techniques are very effective in the treatment of neural disorders in which the pain is the chief complain. It removes the inflammatory exudates and facilitates tissue oxygenation which help to restore the normal physiological status of the nerves. On the other hand, tensioner techniques are used to induce viscoelastic, movement related and physiological reactions in the neural tissues. Tension is applied to the neural tissues via increasing the distance between both ends of the nerve (15).
Slider techniques mobilize the nerve over their distal root while relieve stress over their proximal attachment and vice versa. On the other hand, tensioner techniques further mobilize the nerve over their proximal and distal attachment at the same time. Thus, slider techniques induce less nerve strain than tensioner techniques (33).
The findings of this study are in line with the results of the in vivo trial using ultrasound imaging conducted by Ellis et al., (34) who measured longitudinal sciatic nerve movement during the slider and tensioner neurodynamic mobilization techniques. He founded that both techniques induced improvement in sciatic nerve mobility and excursion with a more significant effect for the slider technique.
Moksha et al., (35) compared the effectiveness of the slider and tensioner neurodynamic mobilization techniques combined with home exercise program on 60 patients with Non-specific LBP associated with radicular lower limb symptoms. He founded that both techniques have better positive effects on reducing pain intensity, increasing hip flexion ROM, and improving functional disability with more significant effect for the slider neurodynamic mobilization technique in all outcomes measured. This results are in contrast to our findings of this study regarding the pain intensity and functional disability, which may be attributed to differences in sample size being double of the sample used in current work.
The slider technique had immediate effect on improving knee extension ROM in patients with sciatica (36). It improved knee extension and hip flexion ROM more than the tensioner technique group or the control joint mobilization group in patients with short hamstring syndrome in a recent randomized controlled trial (RCT) with a large sample size of 105 participants (37).
The findings of the current study differs from the trial conducted by Herrington (38), who applied both slider and tensioner neurodynamic mobilization techniques and founded that both techniques increased ROM of knee extension with no statistical significant difference between them. It may be attributed to the participants age and activity level being young healthy female subjects. Another comparison for the healthy subjects with hamstring tightness was applied in the three-armed RCT conducted by Sharma et al., (39) who combined the slider and tensioner neurodynamic mobilization techniques with static hamstrings stretching in two separate experimental groups, while the third control group received only static hamstrings stretching. He founded that both techniques have better effects than static stretching in improving knee extension ROM but with no statistically significant difference between them.
The slider technique, when applied in combination with conventional physiotherapy (CP), was founded to be more effective in reducing pain intensity, improving hip flexion ROM, and improving functional capabilities more than the CP alone for patients with chronic discogenic sciatica (40). Furthermore, pain intensity, hip flexion ROM, functional disability, and lumbar flexion ROM measured by MMST were improved when slider technique combined with CP compared to CP alone in patients with sub-acute discogenic sciatica (41).
The current work took a step in getting an evidence of the best treatment modalities in the management of sciatica and its related disabilities, but it faced some limitations. Pain intensity measurements may be affected by the patient’s psychological conditions during assessment. Furthermore, variations in individual’s commitment to the study assumptions and ergonomic advice may have affected the results. The patient’s commitment in this critical time while the pandemic Covid-19 invades the whole world was affected, which made some patients involuntarily not capable to complete the treatment protocol.
Further studies should be conducted including large sample sizes with long-term follow up. Furthermore, more objective tools e.g., electro goniometer or computer assisted video motion analysis system to measure ROM should be used. Ultrasonography, to assess nerve excursion, should be applied in well-designed trials.