Safety and Efficacy of Zynrelef® in Combination with a Single Unilateral or Bilateral Nerve Block Performed Prior to Surgery.

Purpose: The FDA recently approved Zynrelef® (A viscous solution of extended release of bupivacaine and meloxicam) to be applied at closure and providing postoperative analgesia for 72 hrs. Although the FDA didn't restrict the use of nerve blocks in combination with this formulation, the safety and efficacy of such a combination has yet to be documented. This quality improvement study investigated this combination within the FDA-approved indications. Methods: Selected surgeons at two hospitals were chosen to use Zynrelef®. According to the standard of care, surgeons were also allowed to request single nerve blocks before surgery. The type of nerve blocks (unilateral or bilateral) performed included quadratus lumborum and paravertebral blocks for abdominal surgery, and adductor canal block for total knee replacement. Each block was performed with 20 mL of 0.375% bupivacaine (n=129) or 0.5% of ropivacaine (n=30). Pain scores, opioid consumption, and prescription refill requests at discharge were recorded. Patients discharged on the same day of surgery were separated into two groups-those who received single nerve blocks plus an Zynrelef® (group 1) vs. those receiving Zynrelef® only (group 2) and was analyzed using an un-paired t-test. Results: A total of 184 patients received Zynrelef®, including 25 patients who didn't receive blocks, 44 who received unilateral blocks and 114 who received bilateral blocks. No symptoms suggestive of Local Anesthetic Toxicity (LAST) were observed. The use of the combination was associated with a 50% reduction in the number of patients filling their opioid prescription. Conclusion: This study provides evidence that the combination of a single unilateral or bilateral nerve block with Zynrelef® is safe.

Cognitive effects of dopamine depletion in the context of diminished acetylcholine signaling capacity in mice.

A subset of patients with Parkinson's disease acquires a debilitating dementia characterized by severe cognitive impairments (i.e. Parkinson's disease dementia; PDD). Brains from PDD patients show extensive cholinergic loss as well as dopamine (DA) depletion. We used a mutant mouse model to directly test whether combined cholinergic and DA depletion leads to a cognitive profile resembling PDD. Mice carrying heterozygous deletion of the high-affinity, hemicholinium-3-sensitive choline transporter (CHT(HET)) show reduced levels of acetylcholine throughout the brain. We achieved bilateral DA depletion in CHT(HET) and wild-type (WT) littermates via intra-striatal infusion of 6-hydroxydopamine (6-OHDA), or used vehicle as control. Executive function and memory were evaluated using rodent versions of cognitive tasks commonly used with human subjects: the set-shifting task and spatial and novel-object recognition paradigms. Our studies revealed impaired acquisition of attentional set in the set-shifting paradigm in WT-6OHDA and CHT(HET)-vehicle mice that was exacerbated in the CHT(HET)-6OHDA mice. The object recognition test following a 24-hour delay was also impaired in CHT(HET)-6OHDA mice compared with all other groups. Treatment with acetylcholinesterase (AChE) inhibitors physostigmine (0.05 or 0.1 mg/kg) and donepezil (0.1 and 0.3 mg/kg) reversed the impaired object recognition of the CHT(HET)-6OHDA mice. Our data demonstrate an exacerbated cognitive phenotype with dual ACh and DA depletion as compared with either insult alone, with traits analogous to those observed in PDD patients. The results suggest that combined loss of DA and ACh could be sufficient for pathogenesis of specific cognitive deficits in PDD.