Impact of close and positive margins in transoral laser microsurgery for TIS-T2 glottic cancer

Introduction: Transoral laser microsurgery (TLM) represents one of the most effective treatment strategies for us 12 glottic squamous cell carcinomas (SCC). The prognostic influence of close/positive margins is still debated, and the role of narrow band imaging (NBI) in their intraoperative definition is still to be validated on large cohort of patients. This study analyzed the influence of margin status on recurrence-free survival (RFS) and disease specific survival (DSS).Methods: We retrospectively studied 507 cases of pTis-Tib (Group A) and 127 cases of pT2 (Group B) glottic SCC. We identified the following margin status: negative (n = 232), close superficial (n = 79), close deep (CD) (n = 35), positive single superficial (n = 146), positive multiple superficial (n = 94), and positive deep (n = 48) and analyzed their impact on RFS and DSS. Close margins were defined by tumor-margin distance <1 mm. PreTLM margins were defined by white light in 323 patients, whereas NBI was employed in 311 patients.Results: In Group A, DSS and RFS were reduced in positive multiple superficial and positive deep margins (DSS = 96.1 and 97%, both p < 0.05; RFS = 72%, p < 0.001 and 75.8%, p < 0.01). In Group B, DSS was reduced in positive multiple superficial margins (82.4%, p < 0.05). RFS was reduced in positive single superficial, positive multiple superficial, and positive deep margins (62.5, 41.2, and 53.3%, p < 0.01). In the entire population, RFS was reduced in CD margins (77.1%, p < 0.05). Use of NBI led to improvement in RFS and DSS.Conclusion: The study indicates that close and positive single superficial margins do not affect DSS. By contrast, all types of margin positivity predict the occurrence of relapses, albeit with different likelihood, depending on stage/margin type. CD margins should be considered as a single risk factor. Use of NBI granted better intraoperative margins definition

Bilateral selective laryngeal reinnervation in patients with bilateral vocal cord palsy

Objective: Bilateral selective reinnervation of the larynx aims to restore both vocal cord tone and abductor movements in patients with bilateral vocal cord palsy. Methods: Four females and one male treated by bilateral selective reinnervation of the larynx were included in the present study. In all cases, both posterior cricoarytenoid muscles were reinnervated using the C3 right phrenic nerve root through the great auricular nerve graft, while adductor muscle tone was bilaterally restored using the thyrohyoid branches of the hypoglossal nerve through transverse cervical nerve grafts. Results: After a minimum follow-up of 48 months, all patients were successfully tracheostomy free and had recovered normal swallowing. At laryngoscopy, the first patient recovered a left unilateral partial abductor movement, the second had complete bilateral abductor movements, the third did not show improvements of abductor movements, but symptomatology was improved, the fourth recovered partial bilateral abductor movements and the fifth case did not show improvements and needed posterior cordotomy. Conclusions: Bilateral selective laryngeal reinnervation, although a complex surgical procedure, offers a more physiologic recovery in the treatment of bilateral vocal fold paralysis. Selection criteria still needs to be precisely defined to avoid unexpected failures

Gribov Problem for Gauge Theories: a Pedagogical Introduction

The functional-integral quantization of non-Abelian gauge theories is affected by the Gribov problem at non-perturbative level: the requirement of preserving the supplementary conditions under gauge transformations leads to a non-linear differential equation, and the various solutions of such a non-linear equation represent different gauge configurations known as Gribov copies. Their occurrence (lack of global cross-sections from the point of view of differential geometry) is called Gribov ambiguity, and is here presented within the framework of a global approach to quantum field theory. We first give a simple (standard) example for the SU(2) group and spherically symmetric potentials, then we discuss this phenomenon in general relativity, and recent developments, including lattice calculations.Comment: 24 pages, Revtex 4. In the revised version, a statement has been amended on page 11, and References 14, 16 and 27 have been improve