Long-term neuromechanical results of selective tibial neurotomy in patients with spastic equinus foot

• Published in: Acta neurochirurgica 2013-09, Vol.155 (9), p.1731-1743
• Main Authors: Buffenoir, Kévin, Decq, Philippe, Hamel, Olivier, Lambertz, Daniel, Perot, Chantal
• Format: Article
• Language: English
• Subjects: Adult; Aged; Clinical Article - Functional; Female; Humans; Interventional Radiology; Male; Medicine; Medicine & Public Health; Middle Aged; Minimally Invasive Surgery; Muscle Spasticity - surgery; Muscle, Skeletal - innervation; Muscle, Skeletal - surgery; Neurology; Neuroradiology; Neurosurgery; Neurosurgical Procedures - methods; Surgical Orthopedics; Tibial Nerve - surgery; Time; Treatment Outcome; Young Adult
• ISSN: 0001-6268; 0942-0940
• DOI: 10.1007/s00701-013-1770-5

Background The neuromechanical consequences of tibial neurotomy have not been extensively studied. Methods Fifteen patients were evaluated before and after selective tibial neurotomy (after 2 months and after 15 months) by means of clinical, neurophysiological [tendon (T) reflexes, Hoffmann (H) reflexes and maximum motor response, Mmax] and mechanical parameters (passive stiffness of plantar flexors at the ankle). The neurotomy concerned the soleus (100 % of cases), gastrocnemius (20 % of cases), posterior tibial (60 % of cases) and flexor digitorum longus (47 % of cases) nerves. Results Neurotomy provided more than 90 % improvement of clinical spasticity scores, 20 % improvement of walking scores and the angle of passive dorsiflexion (APDF) of the ankle (mean angle: 7°), temporary reduction of the soleus Mmax (18 % at 2 months with return to the preoperative value at 15 months), and lasting reduction of the soleus Hmax/Mmax (68 % at 2 months, 78 % at 15 months) and T/Mmax (84 % at 2 months, 80 % at 15 months). M and H responses of the gastrocnemius (whether or not they were included in the neurotomy) were not modified, while T/Mmax decreased to the same degree as for soleus. Passive stiffness was lastingly decreased from 64.0 Nm/rad to 49.0 Nm/rad (2 months) and 49.5 Nm/rad (15 months). Conclusion Selective tibial neurotomy of the soleus nerve induces long-term reduction of reflex hyperexcitability and passive stiffness of plantar flexors in spastic patients, with no lasting impairment of motor efferents. In parallel, it modifies the tendon reflexes of synergistic muscles (gastrocnemius) not concerned by the neurotomy.