Christophe Milants

Responders to Platelet-Rich Plasma in Osteoarthritis: A Technical Analysis

Purpose To evaluate the similarities and differences between the variety of platelet-rich plasma (PRP) formulations, preparation, and uses to try to determine the best responses for the treatment of knee osteoarthritis. Materials and Methods A comparison of the outcomes of randomized controlled trials (RCTs) included in the 3 most recent and high-quality meta-analyses to classify the different studies in 2 groups (bad responders group (BRG) and very good responders group (VGRG)). Results and Discussion From the 19 RCTs analyzed, 7 trials were included in the VGRG and 4 in the BRG. In VGRG, 1 or 2 injections were performed in 4/7 trials, time between injections was 2 to 3 weeks in 4/5 studies with many injections, volume injected varied from 2.5 to 8 mL, and single spinning technique was used in 5/7 studies. PRP classification was Mishra 4B and PAWP2Bβ in 5/7 studies. The use of PRP with leukocytes is only found in the BRG. Conclusion There is a lack of standardization in PRP preparation technique for knee osteoarthritis. However it appears that the use of a single spinning technique, a platelet concentration lower than 5 times the baseline, and avoidance of leukocytes should be preferred.

iMAX: a new tool to assess peripheral motor axonal hypoexcitability

https://doi.org/10.1016/j.clinph.2017.09.111 1388-2457/ 2017 International Federation of Clinical Neurophysiology. In routine electrodiagnostic procedures, classical parameters allow assessment of motor unit loss/reinnervation (CMAP amplitude) and motor conduction slowing (motor distal latency, motor conduction velocity, F waves), but none evaluates peripheral motor axon hypoexcitability. Yet everyone has experienced that in a demyelinating neuropathy it is often necessary to increase above normal the amount of current to obtain a supramaximal motor response. Excitability properties of human peripheral nerves can be assessed by various neurophysiological methods (Brismar, 1985; Kiernan et al., 2000; Burke et al., 2001), but they are not often used in daily practice because they are time consuming and they require a specific collection system and software. The median nerve innervated thenar muscles were studied here with classical motor nerve conduction settings. The ground and recording electrodes consisted of pre-gelled disposable surface electrodes (Alpine Biomed, REF 9013L0453). The recording electrode was placed over the thenar eminence in close proximity to the muscle endplates halfway between the midpoint of the distal wrist crease and the first metacarpophalangeal joint. The reference electrode was placed over the proximal phalanx of the thumb. The ground electrode was placed over the ventral part of the forearm. All data were collected by the same investigator using a Keypoint G3 EMG machine (Natus Medical Incorporated). Compound motor responses were evoked by 1ms constant current square waves through bipolar surface stimulation with two 7 mm diameter felt tip pads, 2.3 cm apart (Natus Medical Incorporated, REF 9013L0362). Despite the fact that previous studies showed that motor nerves have lowest threshold with a stimulus duration of typically 0.2 ms, while sensory nerves can be excited at lowest threshold with a stimulus duration of 1.0 ms (Panizza et al., 1992), we used the longest stimulus duration of 1 ms in order to have if necessary the greater amount of current and to avoid technical limitation in the case of a severe motor axon hypoexcitability. The cathode was 2 cm proximal from the distal wrist crease and the anode was 2.3 cm proximal from the cathode. The bandpass filter setting was set from 2 to 5000 Hz. In accordance with Ohm’s law (voltage = current resistance), skin impedances under the cathode, anode and ground electrode were systematically measured and kept less than 20 kX by gently abrading the skin and wiping it with alcohol. The hand temperature was maintained above 30 C. The iMAX was the minimum stimulus intensity to elicit a maximal compound muscle action potential (CMAP) amplitude. The motor threshold (minimum intensity required to evoke a motor response of at least 100 mV of amplitude) was first measured. Then, the iMAX determination was a 3-step procedure. Firstly, the stimulus intensity was gradually and manually (about

Correlations between MUNIX and adapted multiple point stimulation MUNE methods

OBJECTIVE The aim of this study was to evaluate how the motor unit number index (MUNIX) is related to the adapted multiple point stimulation (AMPS) technique. METHODS MUNIX and AMPS technique were prospectively performed on thenar muscles in 20 consecutive patients referred to our neurophysiological laboratory with the clinical diagnosis of a possible motoneurone disorder (MND). The clinical and paraclinical assessment confirmed the diagnosis of MND in 13 out of 20 patients, amyotrophic lateral sclerosis (ALS) in 9 (with MND group). In the other 7 patients, there were neither evidence of MND, nor of any peripheral nervous system disease (without MND group). RESULTS AMPS and MUNIX data were significantly (p < 0.001) lower in patients with MND than in patients without MND. There was a strong significant positive linear correlation between AMPS and MUNIX values (n = 20; R = 0.83; p < 0.01). CONCLUSION Both MUNIX and AMPS methods could serve as a reliable marker to document the motor unit loss. SIGNIFICANCE The present paper constitutes one more clue of MUNIX reliability.