Section 4 Plastic and Reconstructive Problems

TR I NDADE DE ALME I DA ET AL

Prager and colleagues evaluated two different dilu- tions (25 and 40 U/mL) of incobotulinumtoxinA in the treatment 40 patients with glabellar lines. They also found no significant difference in the initial results or after 4 months of follow up between the two groups. 76

found that the higher dilution group (20 U/mL) achieved greater neuromuscular blockade and spasticity reduction than an endplate-targeted (injection to areas known to be dense in endplates) or concentrated solution. Two studies were conducted in children with cere- bral palsy and limb spasticity. One used onabotuli- numtoxinA in 38 children at concentrations of 12.5 ( n = 19) and 50 U/mL ( n = 19) in the gastrocnemius muscles for reducing ankle plantar flexor spasticity. It was found that, although there were no significant differences in physical evaluation and gait analysis, the large-volume group presented side effects more frequently, making a concentrated solution a better option. 84 In another randomized controlled trial, 22 spastic diplegic or quadriplegic children with cerebral palsy received a fixed dose of abobotuli- numtoxinA. Dilutions of 500 U/5mL and 500 U/ 1mL were injected in each gastrocnemius muscle. 85 The more diluted preparation was considered more effective. There is no standardized dilution for BoNT treat- ment of focal hyperhidrosis. Dilutions reported vary from 1 to 10mL of saline 86–88 for onabotulinum- toxinA, with most clinicians using between 2 and 5mL. As for abobotulinumtoxinA, reconstitution volumes vary between 1.25 and 10mL, 86–89 the use of 2.5 to 5mL being most frequent. In the only study with incobotulinumtoxinA for hyperhidrosis, the dilution used was 10 U/mL. 90 In an open, comparative study, nine volunteers were injected in the axillary region; 3 U of onabotuli- numtoxinA was diluted in 1, 2, 3, 4, and 5mL of saline solution. Patient assessments using the iodine- starch test showed no difference in anhydrotic ha- los. 91 Another trial compared the same 5-U dose of abobotulinumtoxinA in three different dilutions (0.2, 0.4 and 0.6mL) injected in the backs of three patients with compensatory hyperhidrosis. Larger anhydrotic halos were found with the more-diluted Hyperhidrosis

Blepharospasm

Boyle and colleagues studied the effect of high- and low-concentration onabotulinumtoxinA for the treatment of benign essential blepharospasm. They injected 16 patients with concentrations of 10 and 100 U/mL and followed them for 8 months. No sig- nificant differences were reported in efficacy or complications. 77

Non Facial Muscles

Experimental Studies

Shaari and colleagues treated the tibialis anterior muscle in rats and found that a constant dose of 0.2 U of BoNT resulted in greater paralysis when injected in larger volumes. 78 Ten years later, Kim and colleagues injected 16 rabbits with 10 U of on- abotulinumtoxinA at concentrations of 20 and 100 U/mL and drew the same conclusions. 79 A group from Korea 80,81 injected a fixed dose of 2.5U of onabotulinumtoxinA into the human extensor digitorum brevis muscle in two dilutions (5 and 25 U/mL) and measured the compound muscle action potential amplitude. They concluded that a fivefold increase in volume did not enhance the par- alyzing effect of onabotulinumtoxinA. Francisco and colleagues treated 13 patients with 60U diluted to 50 or 100U/mL for wrist and finger flexor spasticity and found no significant differences either. 82 Gracies and colleagues 83 conducted a double-blind randomized controlled trial with 21 individuals with spastic elbow flexors using 160 U of onabotulinum- toxinA in two dilutions (20 and 100 U/mL). They Limb Muscle Dystonias and Spasticity

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