Quantifying Tumor and Vasculature Deformations during Laryngoscopy.

Retractors and scopes used in head and neck surgery to provide adequate surgical exposure also deform critical structures in the region. Surgeons typically use preoperative imaging to plan and guide their tumor resections, however the large tissue deformation resulting from placement of retractors and scopes reduces the utility of preoperative imaging as a reliable roadmap. We quantify the extent of tumor and vasculature deformation in patients with tumors of the larynx and pharynx undergoing diagnostic laryngoscopy. A mean tumor displacement of 1.02 cm was observed between the patients' pre- and intra-operative states. Mean vasculature displacement at key bifurcation points was 0.99 cm. Registration to the hyoid bone can reduce tumor displacement to 0.67 cm and improve carotid stem angle deviations but increase overall vasculature displacement. The large deformation results suggest limitations in reliance on preoperative imaging and that using specific landmarks intraoperatively or having more intraoperative information could help to compensate for these deviations and ultimately improve surgical success.

Image-guided surgery in otolaryngology: A review of current applications and future directions in head and neck surgery.

Image-guided surgery (IGS) has become a widely adopted technology in otolaryngology. Since its introduction nearly three decades ago, IGS technology has developed rapidly and improved real-time intraoperative visualization for a diverse array of clinical indications. As usability, accessibility, and clinical experiences with IGS increase, its potential applications as an adjunct in many surgical procedures continue to expand. Here, we describe the basic components of IGS and review both the current state and future directions of IGS in otolaryngology, with attention to current challenges to its application in surgery of the nonrigid upper aerodigestive tract.

Deletion of a non-canonical regulatory sequence causes loss of Scn1a expression and epileptic phenotypes in mice.

BACKGROUND: Genes with multiple co-active promoters appear common in brain, yet little is known about functional requirements for these potentially redundant genomic regulatory elements. SCN1A, which encodes the NaV1.1 sodium channel alpha subunit, is one such gene with two co-active promoters. Mutations in SCN1A are associated with epilepsy, including Dravet syndrome (DS). The majority of DS patients harbor coding mutations causing SCN1A haploinsufficiency; however, putative causal non-coding promoter mutations have been identified. METHODS: To determine the functional role of one of these potentially redundant Scn1a promoters, we focused on the non-coding Scn1a 1b regulatory region, previously described as a non-canonical alternative transcriptional start site. We generated a transgenic mouse line with deletion of the extended evolutionarily conserved 1b non-coding interval and characterized changes in gene and protein expression, and assessed seizure activity and alterations in behavior. RESULTS: Mice harboring a deletion of the 1b non-coding interval exhibited surprisingly severe reductions of Scn1a and NaV1.1 expression throughout the brain. This was accompanied by electroencephalographic and thermal-evoked seizures, and behavioral deficits. CONCLUSIONS: This work contributes to functional dissection of the regulatory wiring of a major epilepsy risk gene, SCN1A. We identified the 1b region as a critical disease-relevant regulatory element and provide evidence that non-canonical and seemingly redundant promoters can have essential function.

Tumor phantom for training and research in transoral surgery.

OBJECTIVE: With the paradigm shift towards minimally invasive surgical techniques such as transoral laser microsurgery and transoral robotic surgery for resection of head and neck malignancies, there is a need to enhance the surgical training of these techniques as well as provide a platform for testing new approaches and technologies. The steeper learning curve associated with minimally invasive surgical techniques may be mitigated with the use of tumor phantoms (TP) placed in cadaver models. METHODS: An injectable TP was developed using an agar-gelatin base, unsalted chicken stock, deionized water, food coloring for visual mimicry, and iohexol for radiographic mimicry. Four percentage glutaraldehyde was used as a cross-linking agent for solidification of the TP. The TP was then injected in various mucosal anatomic sites in four unfixed cadaver heads. Visual, radiographic, and tactile mimicry was assessed via endoscopy, CT scan, and tumor dissection and palpation, respectively. RESULTS: Tumor phantom injection was successfully achieved in all four cadaver heads. Visually and tactilely, the TP demonstrated similar color change, induration, and firmness of a typical squamous cell carcinoma (SCCa). However, ulceration that is often seen with SCCa could not be replicated. CT mimicry was compared with nine patients with known SCCa. Tumor radiodensity in the nine patients was between 77 and 110 HU (mean 86.3 HU) whereas TP radiodensity was 59 and 127 HU (mean 93.7 HU), with no significant difference between groups (P = .21). CONCLUSION: This inexpensive, easy to apply, and unique tumor phantom could be used both to train transoral techniques and as a tool to further investigate new approaches and technologies for transoral surgery. LEVEL OF EVIDENCE: NA.

A comparison of postoperative throat and neck complaints after the use of the i-gel and the La Premiere disposable laryngeal mask: a double-blinded, randomized, controlled trial.

BACKGROUND: Many supralaryngeal airway devices are available. Because of the absence of an inflatable cuff, we hypothesized that use of the i-gel should produce fewer postoperative throat and neck complaints compared with a standard disposable laryngeal mask (LM). METHODS: Two hundred eighteen patients were randomized to have either an i-gel or La Premiere LM airway placed for airway management. Patients were interviewed postoperatively for throat and neck complaints at 1, 24, and 48 h. Interviewers and patients were blinded to the device used. RESULTS: One hundred nine patients had an i-gel and 103 had a La Premiere supraglottic device inserted. The incidence of sore throat was significantly lower with the i-gel than with LM at 1 (6 vs 32), 24 (7 vs 48), and 48 h (5 vs 25). Similar results were seen for dysphagia. The incidence of neck pain was also lower for the i-gel at 24 (1 vs 7) and 48 h (1 vs 7). CONCLUSION: In this randomized study, the i-gel supraglottic device resulted in a lower incidence of throat and neck complaints than the La Premiere LM airway.