ABSTRACT
Background: Chronic postoperative pain occurs in up to 21·7 per cent of patients undergoing open inguinal hernia repair. Several mesh fixation techniques using glue or self-gripping meshes have been developed to reduce postoperative pain. The aim of this meta-analysis was to evaluate RCTs comparing adhesional/self-gripping and sutured single-layer open mesh fixations in the repair of inguinal herniation, with postoperative pain as endpoint. Methods: PubMed, Embase and Cochrane CENTRAL databases were searched systematically for RCTs according to the PRISMA guidelines; the study was registered at PROSPERO (CRD42017056373). Different fixation methods were analysed. The primary outcome, chronic pain, was defined as a postoperative visual analogue scale (VAS) score of at least 3 at 12 months. Secondary outcomes were mean VAS score at 1 week and at 1 month after surgery. Results: Twenty-three studies including 5190 patients were included in the meta-analysis. Adhesional (self-adhering or glued) or self-gripping fixation methods were associated with a significantly lower VAS score at 1 week (mean difference -0·49, 95 per cent c.i. -0·81 to -0·17; P = 0·003) and at 1 month (mean difference -0·31, -0·58 to -0·04; P = 0·02) after surgery than suture fixation, but the incidence of chronic pain after 12 months was similar in the two groups (odds ratio 0·70, 95 per cent c.i. 0·30 to 1·66). Differences in recurrences and complications between groups did not reach statistical significance. Conclusion: There was no difference in the incidence of chronic pain 12 months after different mesh repair fixation techniques despite significant reductions in short-term postoperative pain favouring a non-sutured technique. There were no differences in recurrence rates or in rates of other complications at 1 year.
Subject(s)
Hernia, Inguinal/surgery , Herniorrhaphy/adverse effects , Pain, Postoperative/epidemiology , Surgical Mesh/adverse effects , Sutures/adverse effects , Adult , Aged , Aged, 80 and over , Chronic Pain/epidemiology , Equipment Design , Female , Humans , Incidence , Male , Middle Aged , Pain, Postoperative/prevention & control , Randomized Controlled Trials as Topic , Recurrence , Suture Techniques , Visual Analog ScaleABSTRACT
The emission spectrum of individual high-quality ZnO nanowires consists of a series of Fabry-Pérot-like eigenmodes that extend far below the band gap of ZnO. Spatially resolved luminescence spectroscopy shows that light is emitted predominantly at both wire ends, with identical spectra reflecting standing wave polariton eigenmodes. The intensity of the modes increases supralinearly with the excitation intensity, indicating that the mode population is governed by scattering among polaritons. Due to strong light-matter interaction, light emission from a ZnO nanowire is not dictated by the electronic band diagram of ZnO but depends also on the wire geometry and the excitation intensity. Delocalized polaritons provide a natural explanation for the pronounced subwavelength guiding in ZnO wires that has been reported previously.
ABSTRACT
Germanium is electrodeposited in a template formed from a dried suspension of silica spheres. The germanium completely fills the pores of the silica matrix. The semiconductor, as deposited, is amorphous but can be crystallized by annealing. Selective dissolution of the silica template gives a macroporous germanium-air sphere matrix, which offers interesting possibilities for photonic applications.
