Smart PEEK Modified by Self-Initiated Surface Graft Polymerization for Orthopedic Bearings

Poly(ether-ether-ketone) (PEEK)s are a group of polymeric biomaterials with excellent mechanical properties, chemical stability, and nonmagnetism. In the present study, we propose a novel self-initiated surface graft polymerization technique, using which we demonstrate the fabrication of a highly hydrophilic and biocompatible nanometer-scale layer on the surfaces of PEEK and carbon fiber-reinforced PEEK (CFR-PEEK) by the photoinduced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) without using any photoinitiators. The thus formed hydrophilic and smooth 100-nm-thick PMPC-grafted layer caused a significant reduction in the sliding friction of the bearing interface because the thin water film and hydrated PMPC layer acted as extremely efficient lubricants (so-called fluid-film lubrication or hydration lubrication). Fluid-film lubrication suppressed the direct contact of the counter-bearing surface with the PEEK substrate and thus reduced the frictional force. A PMPC-grafted layer is therefore expected to significantly increase bearing durability. Furthermore, the PMPC-grafted layer shows unique phenomena, e.g., it prevents damage of the metal counter surface regardless of the carbon fiber content of CFR-PEEK. Smart PEEK using the self-initiated surface graft polymerization of MPC should lead to development of novel orthopedic bearings. Keywords: poly(ether-ether-ketone), 2-methacryloyloxyethyl phosphorylcholine, surface modification, photopolymerization, joint replacement, wear mechanis

Unilateral Multiple Facial Nerve Branch Reconstruction Using “End-to-side Loop Graft” Supercharged by Hypoglossal Nerve

Background: Extensive facial nerve defects between the facial nerve trunk and its branches can be clinically reconstructed by incorporating double innervation into an end-to-side loop graft technique. This study developed a new animal model to evaluate the technique’s ability to promote nerve regeneration. Methods: Rats were divided into the intact, nonsupercharge, and supercharge groups. Artificially created facial nerve defects were reconstructed with a nerve graft, which was end-to-end sutured from proximal facial nerve stump to the mandibular branch (nonsupercharge group), or with the graft of which other end was end-to-side sutured to the hypoglossal nerve (supercharge group). And they were evaluated after 30 weeks. Results: Axonal diameter was significantly larger in the supercharge group than in the nonsupercharge group for the buccal (3.78 ± 1.68 vs 3.16 ± 1.22; P < 0.0001) and marginal mandibular branches (3.97 ± 2.31 vs 3.46 ± 1.57; P < 0.0001), but the diameter was significantly larger in the intact group for all branches except the temporal branch. In the supercharge group, compound muscle action potential amplitude was significantly higher than in the nonsupercharge group (4.18 ± 1.49 mV vs 1.87 ± 0.37 mV; P < 0.0001) and similar to that in the intact group (4.11 ± 0.68 mV). Retrograde labeling showed that the mimetic muscles were double-innervated by facial and hypoglossal nerve nuclei in the supercharge group. Conclusions: Multiple facial nerve branch reconstruction with an end-to-side loop graft was able to achieve axonal distribution. Additionally, axonal supercharge from the hypoglossal nerve significantly improved outcomes

Prognostic Value of Pretreatment Red Blood Cell Distribution Width in Patients With Esophageal Cancer Who Underwent Esophagectomy

Objective:. This comprehensive analysis aimed to elucidate the mechanism underlying how high pretreatment red blood cell distribution width (RDW) reflects poor prognosis after esophagectomy for esophageal cancer. Background:. Several cohort studies have reported that preoperative RDW might be a predictive marker for poor prognosis after esophagectomy; however, the underlying mechanism of this relationship has not been elucidated. Methods:. This study included 626 patients with esophageal cancer who underwent esophagectomy between April 2005 and November 2020. A retrospective investigation of the association between pretreatment RDW and clinicopathological features, blood data, short-term outcomes, and prognosis was conducted using a prospectively entered institutional clinical database and the latest follow-up data. Results:. Of 626 patients, 87 (13.9%) had a high pretreatment RDW. High RDW was significantly associated with several disadvantageous characteristics regarding performance status, the American Society of Anesthesiologists physical status, respiratory comorbidity, and nutritional status. Similarly, high RDW correlated with frequent postoperative morbidities (respiratory morbidity and reoperation; P = 0.022 and 0.034, respectively), decreased opportunities for adjuvant chemotherapy (P = 0.0062), and increased death from causes other than esophageal cancer (P = 0.046). Finally, RDW could be an independent predictor of survival after esophagectomy (hazard ratio, 1.47; 95% confidence interval, 1.009–2.148; P = 0.045). Conclusion:. High pretreatment RDW reflected various adverse backgrounds and it could be a surrogate marker of poor prognosis in patients who have undergone esophagectomy for esophageal cancer