Faculty Bibliography

OBJECTIVE It is common for a medical disorder to be managed or researched by individuals who work within different specialties. It is known that both neurosurgeons and neurotologists manage vestibular schwannoma (VS) patients. While overlap in specialty focus has the potential to stimulate multidisciplinary collaboration and innovative thinking, there is a risk of specialties forming closed-communication loops, called knowledge silos, which may inhibit knowledge diffusion. This study quantitatively assessed knowledge sharing between neurosurgery and otolaryngology on the subject of VS. METHODS A broad Web of Science search was used to download details for 4439 articles related to VS through 2016. The publishing journal's specialty and the authors' specialties (based on author department) were determined for available articles. All 114,647 of the article references were categorized by journal specialty. The prevalence of several VS topics was assessed using keyword searches of titles. RESULTS For articles written by neurosurgeons, 44.0% of citations were from neurosurgery journal articles and 23.4% were from otolaryngology journals. The citations of otolaryngology authors included 11.6% neurosurgery journals and 56.5% otolaryngology journals. Both author specialty and journal specialty led to more citations of the same specialty, though author specialty had the largest effect. Comparing the specialties' literature, several VS topics had significantly different levels of coverage, including radiosurgery and hearing topics. Despite the availability of the Internet, there has been no change in the proportions of references for either specialty since 1997 (the year PubMed became publicly available). CONCLUSIONS Partial knowledge silos are observed between neurosurgery and otolaryngology on the topic of VS, based on the peer-reviewed literature. The increase in access provided by the Internet and searchable online databases has not decreased specialty reference bias. These findings offer lessons to improve cross-specialty collaboration, physician learning, and consensus building.

Cochlear implants (CIs) have proven to be a useful treatment option for individuals with severe-to-profound hearing loss by providing improved access to one's surrounding auditory environment. CIs differ from traditional acoustic amplification by providing information to the auditory system via electrical stimulation. Both postlingually deafened adults and prelingually deafened children can benefit from a CI; however, outcomes with a CI can vary. Numerous factors can impact performance outcomes with a CI. It is important for the audiologist to understand what factors might play a role and impact performance outcomes with a CI so that they can effectively counsel the recipient and their family, as well as establish appropriate and realistic expectations with a CI. This review article will discuss the CI candidacy process, CI programming and postoperative follow-up care, as well as considerations across the lifespan that may affect performance outcomes with a CI.

INTRODUCTION/BACKGROUND:Occipital-frontal nerve stimulation is an off-label therapy for treating chronic refractory migraine and orofacial pain. Though effective, patients experience a high rate of complications including lead migration and erosion through the overlying skin. CASE DESCRIPTION/METHODS:We present a case of frontal electrode erosion that was revised via pericranial flap repair. The patient presented with multiple lead migrations, necessitating multiple revision surgeries with eventual frontal wound dehiscence. The choice was made to wrap the electrode in a pericranial flap to prevent recurrent lead migration. Two weeks postoperatively, the wound was well healed and the patient reported that the midline electrode was functioning properly. DISCUSSION/CONCLUSIONS:Pericranial flap revision confers little additional risk when compared with simple wound closure, and the surgeon can proceed without total electrode removal, additional incisions, or lead tunneling. The flap provides a highly vascular additional layer of stability to the electrode, reducing the likelihood of further lead exposure without compromising the efficacy of the device. These results suggest that endoscopic pericranial flap revision is a viable technique for the repair of occipital nerve stimulation lead erosions.

Posterior glottic stenosis (PGS) describes a laryngeal disorder in which worsening degrees of scarring limit abduction of the vocal folds and/or arytenoids. It can be congenital or acquired. Generally, the acquired form is the result of chronic endotracheal tube trauma to the posterior larynx. Symptoms of acquired PGS usually begin four to eight weeks after extubation, and present as gradually worsening stridor and shortness of breath as the laryngeal obstruction becomes more severe. Without intervention, PGS can cause total obstruction and respiratory failure. The mainstay of treatment for PGS is surgery. We present a case in which an infant patient with PGS was treated with a posterior cricoid split and insertion of a thyroid ala graft. The graft was bolstered in place with an appropriately-sized endotracheal tube during a six-day period of postoperative intubation. We report this as a novel surgical approach, as a literature review did not uncover that this technique has been previously described. Our patient has had excellent airway and voice outcomes. His swallow outcomes have been difficult to assess, as the patient has shown signs of global delay.

Evidence-based reviews of drugs causing medication-induced salivary gland dysfunction, such as xerostomia (sensation of oral dryness) and subjective sialorrhea are lacking. To compile a list of medicaments that influence salivary gland function, electronic databases were searched for relevant articles published up to June 2013. A total of 269 papers out of 3,867 records located satisfied the inclusion criteria (relevance, quality of methodology, strength of evidence). A total of 56 active substances with a higher level of evidence and 50 active substances with a moderate level of evidence of causing salivary gland dysfunction are described in this article. While xerostomia was a commonly reported outcome, the objective effect on salivary secretion was rarely measured. Xerostomia was, moreover, mostly reported as a negative side effect instead of the intended effect of that drug. A comprehensive list of medications having documented effects on salivary gland function or symptoms was compiled, which may assist practitioners in assessing patients who complain of dry mouth while taking medications

In contrast to adulthood, meningiomas are rare among children and adolescents. However, the molecular relations between both groups have not been elucidated in detail. We have analyzed 41 tumor samples from 37 pediatric meningioma patients (female: 17, male: 20; age range: 1-21 years). Atypical meningioma WHO grade II was the most frequent histological subtype (N=14, 38%). Most tumors were located at the convexity (N=18) or the skull base (N=15). Lack of SMO, AKT, KLF4/TRAF7 mutation in Sanger sequencing (n=22) prompted whole genome sequencing of a subset (n=7). All cases exhibited bi-allelic mutation of NF2 (combined large deletion and germline (5/7) or somatic (2/7) base exchanges/frameshifts). Subsequently, representative samples of all 37 patients were subjected to 450K DNA methylation profiling and remaining DNA to sequencing of a brain tumor specific gene panel. Loss of chromosome 22 was frequently detected (N=28, 76%), followed by loss of chromosome 1 (N=12, 32%) and chromosome 18 (N=7, 19%). Moreover, a separation into three groups was evident: One group covering all clearcell meningiomas with enrichment for SMARCE1 mutations, a second group dominated by atypical meningiomas, and a third group covering benign WHO grade I meningiomas, as well as rare subtypes such as rhabdoid meningiomas. Compared to adult tumors, the majority of pediatric meningiomas clustered in a separate group both by unsupervised hierarchical and clustering and t-stochastic nearest neighbor embedding. Analysis of four tumor recurrences did not reveal changes compared to the primary tumor. These data suggest that pediatric meningiomas are fundamentally different from adult counterparts

BACKGROUND: Tumor heterogeneity presents a major challenge to cancer diagnosis and treatment. In addition to interpatient tumor variability, intratumoral heterogeneity characterized by distinct molecular and phenotypic profiles is increasingly recognized as a major cause of therapy resistance and cancer recurrence. Because DNA methylation patterns are largely responsible for determining cell-type-specific functioning, we hypothesized that distinct DNA methylation and proteomic alterations could be identified in histologically-defined invasive and proliferative tumor cell populations in human isocitrate dehydrogenase 1 (IDH1)- mutated and wild-type glioblastoma (GBM).
METHOD(S): Formalin-fixed paraffin-embedded tissue sections of human adult IDH1-mutated and wild-type GBM were laser-microdissected (LM) into perinecrotic pseudopalisading tumor cells (PPCs), non-pseudopalisading tumor core cells (NPPCs), invasive subpial spread (SPS) and perivascular satellitosis tumor cells and brain adjacent to tumor cells prior to analysis and compared to non-microdissected tumor (NMT) and/or germline DNA. Genomewide DNA methylation and chromosomal copy numbers were determined with Infinium MethylationEPIC 850K BeadChip and intratumoral DNA methylation patterns compared by unsupervised hierarchical clustering. Label-free quantitative liquid chromatography-mass spectrometry of proteins was performed and proteins differentially expressed across LM areas subjected to pathway enrichment analysis.
RESULT(S): Unsupervised hierarchical classification of DNA methylation patterns for each LM area and NMT demonstrated remarkable clustering for all patients, based on methylation probe and methylated gene patterns. Proteomics analysis showed upregulation of hypoxia-inducible factor-1 inducible proteins in hypoxic PPCs. Out of 1819 proteins quantified, 5 were overexpressed and 9 underexpressed more than 10-fold in SPS compared with NPPCs and associated with alterations in metabolism, transport, extracellular matrix and apoptosis. Correlation of protein expression and DNA methylation patterns was noted.
CONCLUSION(S): Compared to NPPCs, SPS cells migrating toward the invasive edge share a relatively consistent epigenetic and proteomic signature, suggesting potentially targetable common mechanism(s) of invasion shared among GBM

BACKGROUND:This multicenter, retrospective review documents the initial experience using the Flex system for transoral surgery in 2 United States academic centers. METHODS:All patients who underwent transoral robotic surgery using the Medrobotics Flex Robotic System (Raynham, MA) between September 2015 and May 2017 were reviewed. Rates of successful surgery and complications were evaluated. RESULTS:Thirty-six men and 32 women were enrolled in the study. The average age was 55.6 years (range 17-82 years). The Flex system was used successfully in surgery of the tongue base, the palatine tonsils, the supraglottis, the glottis, the hypopharynx, the oral tongue, and the soft palate. Only 6 cases (7.6%) required readmission after discharge. There were no intraoperative or immediate postoperative complications, with no cases of intraoperative hemorrhage. CONCLUSION/CONCLUSIONS:To the best of our knowledge, this is the first study in the United States evaluating the use of the Flex system to safely resect lesions in the oral cavity, larynx, and pharynx.