The effects of laminectomy surgery on pain, functional disability, sensitization and active trigger points in subjects with lumbar disc herniation

Objectives. To evaluate the effects of laminectomy surgery on pain, functional disability, sensitization and active trigger points in subjects with lumbar disc herniation.Methods. This study was a prospective pre‑post single group study. Seventy‑one patients (42 male and 29 female) have been enrolled in the research with an age range of 20–60 (48 ± 13.41). During 48 hours before surgery, patients were examined by a physiotherapist. Pain intensity were measured by visual analogue scale, disability by oswestry index (Persian version) and sensitivity level using pressure algometer. Three month after laminectomy, the patients were re‑examined for mentioned outcomes again.Results. The majority of the patients (23 cases, 32.4 %) revealed 3 active trigger points of the muscles before surgery. 60 subjects (84.5 %) experienced a gradual onset of leg pain without a trauma history. Lumbar multifidus (74.9 %), medial gastrocnemius (73.2 %), soleus (70.4) gluteus medius (62 %) were the most involved muscles with trigger points before laminectomy. On the other hand, after laminectomy medial gastrocnemius (54.9 %), lateral gastrocnemius (53.5 %), soleus (50.7 %), multifidus (39.4 %) and quadratus lumborum (39.4 %) were the most involved muscles with trigger points. The existence of trigger points in longissimus thoracis (p = 0.04), quadratus lumborum (p = 0.001), gluteus maximus (p = 0.04) and tibialis anterior (p = 0.02) were decreased significantly after laminectomy. Pain, disability and pain pressure threshold revealed significant differences before and after surgery.Discussion. The pattern of active trigger points of muscles was different before and after surgery. Multifidus and gastrocnemius were the most prevalent muscles with myofascial pain syndrome before and after surgery respectively.Conclusion. The present study revealed that pain, disability, number and prevalence of trigger points decreased after lumbar laminectomy. Nevertheless, pressure pain threshold of trigger points increased after surgery. The pattern of active trigger points of muscles was different before and after surgery. Multifidus and gastrocnemius were the most prevalent muscles with myofascial pain syndrome before and after surgery respectively. In fact, current results showed that active trigger points should be considered before and after laminectomy surgery