ABSTRACT
OBJECTIVE: To determine the effect of anterior plating on postoperative dysphagia (POD) among adult patients undergoing elective anterior cervical discectomy and fusion (ACDF) for cervical spondylosis and determine the potential role of demographic and clinical characteristics in the development of POD. METHODS: Consecutive adults undergoing an elective, single-level, ACDF were randomly assigned to receive a stand-alone CoRoent Cage or a CoRoent Cage with a Helix, or HelixMini plate. Patients with a history of cervical spine surgery were excluded. M. D. Anderson Dysphagia Inventory and Bazaz questionnaires were completed at regular intervals for 12 months postoperatively. RESULTS: Twenty-five patients were recruited over a 2-year period, with 8 allocated to receive a stand-alone cage, 5 to receive a cage and Helix Mini plate, and 12 to receive a cage and Helix plate. The POD rate was 68% at 48 hours, before falling to 16% at 6 and 12 months. A longer retraction time was observed in the Helix plate group compared to the stand-alone cage group (7.88; 95% confidence interval, 0.12-15.63; p = 0.046), although there was no difference in the incidence or severity of dysphagia between cohorts at any timepoint. With the exception of body mass index, there was no difference in patients with and without dysphagia, and each of the interventions was equally efficacious with respect to clinical and radiological endpoints. CONCLUSION: Dysphagia is a common consequence of ACDF and, while the placement of a large plate results in longer retraction time, it was not associated with higher rates of dysphagia. Further research is required to identify both patient-specific and surgical contributors to this complication.
ABSTRACT
Twitching motility-mediated biofilm expansion is a complex, multicellular behavior that enables the active colonization of surfaces by many species of bacteria. In this study we have explored the emergence of intricate network patterns of interconnected trails that form in actively expanding biofilms of Pseudomonas aeruginosa. We have used high-resolution, phase-contrast time-lapse microscopy and developed sophisticated computer vision algorithms to track and analyze individual cell movements during expansion of P. aeruginosa biofilms. We have also used atomic force microscopy to examine the topography of the substrate underneath the expanding biofilm. Our analyses reveal that at the leading edge of the biofilm, highly coherent groups of bacteria migrate across the surface of the semisolid media and in doing so create furrows along which following cells preferentially migrate. This leads to the emergence of a network of trails that guide mass transit toward the leading edges of the biofilm. We have also determined that extracellular DNA (eDNA) facilitates efficient traffic flow throughout the furrow network by maintaining coherent cell alignments, thereby avoiding traffic jams and ensuring an efficient supply of cells to the migrating front. Our analyses reveal that eDNA also coordinates the movements of cells in the leading edge vanguard rafts and is required for the assembly of cells into the "bulldozer" aggregates that forge the interconnecting furrows. Our observations have revealed that large-scale self-organization of cells in actively expanding biofilms of P. aeruginosa occurs through construction of an intricate network of furrows that is facilitated by eDNA.
