Facultad de Ciencias de la Salud

OBJECTIVE: To evaluate the pain-relieving effect of transcutaneous electrical nerve stimulation (TENS) during office-based hysteroscopy without sedation. METHODS: We conducted a randomized, double-blind, placebo-controlled trial. Participants were randomly assigned to the active TENS, placebo TENS, or control group. The active TENS intervention consisted of a varying high-frequency (80–100 Hz), 400-microseconds, individually adjusted, high-intensity TENS application with two self-adhesive electrodes placed parallel to the spinal cord at the T10–L1 and S2–S4 levels. In the placebo group, participants were connected to the TENS unit but delivering no electrical stimulation. The primary outcome was self-reported pain intensity (0–100 mm) measured on a visual analog scale at several stages (entry, contact, biopsy, and residual). The minimum clinically relevant difference for the visual analog scale has been previously reported as 10 mm. Sample size was calculated to provide 80% power to show a 10-mm difference (α=0.0125) in the primary outcome. Secondary outcomes included duration of the procedure, vital parameters, vasovagal symptoms, and participant satisfaction index (0–10 rating scale). RESULTS: A total of 138 women (46 per group) participated in the study between January 2016 and April 2016. No differences were found between groups regarding age, weight, body mass index, parity status, menopausal status, or previous hysteroscopy status. Visual analog scale scores highlighted a decrease in pain in the active TENS group compared with the placebo group (entry: −11 mm, 95% confidence interval [CI] −17 to −5; contact: −21.9 mm, 95% CI −30 to −13.9; biopsy: −30.5 mm, 95% CI −47.1 to −13.8, P<.001). Moreover, the reduction in pain reached the minimum clinically relevant difference. Regarding satisfaction, results also revealed differences between active TENS and placebo groups (1.3, 95% CI 0.5–2.2, P=.001). CONCLUSION: Transcutaneous electrical nerve stimulation reduces pain and increases patient satisfaction during office hysteroscopy without sedation.

Various stimuli such as the flexibility of lumbopelvic structures influence the neuromuscular responses of the trunk musculature, leading to different load sharing strategies and reflex muscle responses from the afferents of lumbopelvic mechanoreceptors. This link between flexibility and neuromuscular response has been poorly studied. The aim of this study was to investigate the relationship between lumbopelvic flexibility and neuromuscular responses of the erector spinae, hamstring and abdominal muscles during trunk flexion-extension. Lumbopelvic movement patterns were measured in 29 healthy women, who were separated into two groups according to their flexibility during trunk flexion-extension. The electromyographic responses of erector spinae, rectus abdominis and biceps femoris were also recorded. Subjects with greater lumbar flexibility had significantly less pelvic flexibility and vice versa. Subjects with greater pelvic flexibility had a higher rate of relaxation and lower levels of hamstring activation during maximal trunk flexion. The neuromuscular response patterns of the hamstrings seem partially modulated by pelvic flexibility. Not so with the lumbar erector spinae and lumbar flexibility, despite the assertions of some previous studies. The results of this study improve our knowledge of the relationships between trunk joint flexibility and neuromuscular responses, a relationship which may play a role in low back pain.

Objetivo: Determinar los efectos del estiramiento de la musculatura isquiotibial sobre el patrón de activación del erector spinae durante los movimientos de flexoextensión de tronco. Hipótesis: El estiramiento repetido de la musculatura isquiotibial podría acortar la duración del período del silencio mioeléctrico del erector spinae durante la flexoextensión de tronco. Metodología: Se registraron en 14 sujetos sanos la activación electromiográfica (EMG) del erector spinae y los grados de flexión de cadera durante movimientos de flexoextensión de tronco antes y después de realizar el estiramiento isquiotibial. Las variables de estudio fueron el rango máximo de movimiento de cadera, los porcentajes de flexión de cadera en el offset/onset del erector spinae y la actividad EMG media de este músculo en las fases excéntrica y concéntrica. Resultados: La prueba T mostró que no existen diferencias significativas en el momento de aparición del offset y del onset antes y después del estiramiento. Se observó un aumento significativo de la actividad EMG del erector durante la contracción concéntrica tras el estiramiento. Conclusión: El estiramiento prolongado de las estructuras isquiotibiales no produce variaciones en la duración del período del silencio mioeléctrico del erector spinae, pero sí sobre su actividad EMG media durante la extensión de tronco, con lo que podría estar alterándose la coactivación muscular necesaria para proporcionar estabilidad al raquis lumbar.