A modern multidisciplinary approach to patients suffering from cervical spondylotic myelopathy.

BACKGROUND: The traditional approach to patients suffering from cervical spondylotic myelopathy (CSM) consists of mere assessment of radiological standard magnetic resonance (MR) images and evaluation of surgical indication, depending on clinical symptoms and degree of radiological stenosis. Identification of prognostic factors for surgery remains difficult. Surgery is thought to be able to stop the disease progression, while significant improvements of neurological symptoms are not predictable. METHODS: Authors present a modern approach to patients with CSM, that is comprehensive of clinical, electrophysiological and radiological findings, and that has been developed by a multidisciplinary team of experts (neurosurgeons, neurologists, neuroradiologists). Authors tried to identify the good responders to surgery, as those who really improved symptoms, by performing an integration of these data. This approach has been used in 11 consecutive patients suffering from and operated for CSM at our Institution. The multidisciplinary protocol included the complementary use of electrophysiological (motor and somatosensory evoked potentials), radiological (magnetic resonance, cervical plain and dynamic x-rays), and clinical (modified Japanese Orthopedic Association [mJOA] and Neck Disability Index [NDI] scores, Hirabayashi Recovery Ratio) values. These data were obtained at the preoperative period, and at 3 and 12 months follow-up. We defined as "good responders" those patients having had an improvement of the Hirabayashi Recovery Ratio of 50% and of the NDI of 30%. RESULTS: The mean preoperative mJOA was 12.79 (range 3-17), while the mean mJOA at 3 and 12 months was, respectively, 14.71 and 13.43. However, only the improvement at 3 months was statistically significant, while improvements from the preoperative assessment to 12 months and from 3 to 12 months were not significant. The mean preoperative NDI was 33.57%, while it was 32.43% and 24.36% at 3 and 12 months, respectively. None of these improvements was significant. Concerning response to surgery, we observed 7/11 (63.3%) good responders according to the Hirabayashi Recovery Ratio, and 6/11 (54.5%) good responders according to NDI results. CONCLUSIONS: A modern multidisciplinary approach to patients with CSM is mandatory to investigate the different aspects of the disease. Decompressive surgery was able, in our series, to improve or stabilize clinical symptoms. Further studies are necessary to allow for a proper selection of patients by cumulative analysis of multidisciplinary findings.

Contraction response to muscle percussion: A reappraisal of the mechanism of this bedside test.

OBJECTIVE: To study whether the contraction evoked by muscle percussion stems from the excitation of the muscle or of the nerve and to discuss the changes of this response in neuromuscular disorders. METHODS: In 30 neurologically healthy patients undergoing surgery (for ear, nose, or throat problems unrelated to the study) under general anesthesia with propofol and sufentanil we measured with an electrogoniometer the maximal dorsiflexion of the ankle evoked by reflex hammer percussion of the tibialis anterior muscle before and under neuromuscular junction blockade with rocuronium bromide. In 3 additional healthy volunteers we searched for F-waves to disclose whether percussion excites axons within the muscle. RESULTS: Responses from 28 neurologically healthy patients (15 women) were analyzed after exclusion of 2 due to technical problems. Mean age (SD) was 28 (9) years. Maximal dorsiflexion of the ankle was not significantly modified by neuromuscular junction blockade (mean difference 0.01 mV [95%CI, -0.07 to 0.08], p=0.879). Muscle percussion evoked F-waves in the 3 healthy volunteers tested. CONCLUSIONS: Maximal contraction response to muscle percussion has a muscular rather than a neural origin. However, percussion also excites axons within the muscle. SIGNIFICANCE: These findings may provide clues to understand the changes observed in neuromuscular disorders.

Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise.

High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca(2+) release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca(2+) leak at rest, and depressed force production due to impaired SR Ca(2+) release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca(2+)-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group.