Urinary Retention Following Inguinal Herniorrhaphy: Role of Neuromuscular Blockade Reversal.

BACKGROUND: Nondepolarizing neuromuscular blockade is reversed with neostigmine/glycopyrrolate or sugammadex. Anticholinergic glycopyrrolate decreases bladder detrusor muscle contractility, potentially leading to postoperative urinary retention (POUR). POUR commonly complicates inguinal herniorrhaphy. In this study we assess association between reversal technique and POUR. METHODS: Records of adult patients undergoing unilateral inguinal herniorrhaphy with neuromuscular blockade from January 2013 to September 2020 were reviewed for POUR (unplanned postoperative insertion of urinary catheter). A propensity-adjusted analysis was performed to assess POUR in neostigmine/glycopyrrolate versus sugammadex using inverse probability of treatment weighting (IPTW) to adjust for potential confounding. RESULTS: We identified 181 patients who underwent herniorrhaphy with amnio-steroidal neuromuscular blockers, 75 (41.4%) who received sugammadex and 106 (58.6%) neostigmine/glycopyrrolate. Compared with sugammadex, neostigmine/glycopyrrolate group had longer surgical course [unweighted standardized difference (USTD)=0.38, P=0.004], received more intraoperative opioids (USTD=0.704, P<0.001), more often performed via laparoscopic approach (USTD=0.407, P=0.012), and less often with periprocedural urinary catheter insertion (USTD=0.452, P=0.003). POUR was observed in 2 (3%) of patients in the sugammadex group, and 16 (15%) in neostigmine/glycopyrrolate [unadjusted odds ratio (OR)=0.15; 95% confidence interval (CI): 0.03-0.69; P=0.015, and IPTW OR=0.13; 95% CI: 0.03-0.64; P=0.012]. Results remained similar with further analysis adjusted for opioid administration in the postanesthesia care unit (adjusted IPTW OR=0.18; 95% CI: 0.04-0.88; P=0.034). Of the POUR patients, 9 required unplanned overnight admission and 4 emergency room visit. CONCLUSION: These results suggest that neuromuscular blockade reversal with sugammadex is associated with lower rates of POUR following unilateral inguinal herniorrhaphy. Our results need to be reconfirmed in a randomized prospective study.

Machine intelligence for nerve conduit design and production.

Nerve guidance conduits (NGCs) have emerged from recent advances within tissue engineering as a promising alternative to autografts for peripheral nerve repair. NGCs are tubular structures with engineered biomaterials, which guide axonal regeneration from the injured proximal nerve to the distal stump. NGC design can synergistically combine multiple properties to enhance proliferation of stem and neuronal cells, improve nerve migration, attenuate inflammation and reduce scar tissue formation. The aim of most laboratories fabricating NGCs is the development of an automated process that incorporates patient-specific features and complex tissue blueprints (e.g. neurovascular conduit) that serve as the basis for more complicated muscular and skin grafts. One of the major limitations for tissue engineering is lack of guidance for generating tissue blueprints and the absence of streamlined manufacturing processes. With the rapid expansion of machine intelligence, high dimensional image analysis, and computational scaffold design, optimized tissue templates for 3D bioprinting (3DBP) are feasible. In this review, we examine the translational challenges to peripheral nerve regeneration and where machine intelligence can innovate bottlenecks in neural tissue engineering.