Intraoperative Real-Time Image-Guided Fibular Harvest and Mandibular Reconstruction: A Feasibility Study on Cadaveric Specimens.

BACKGROUND: This study assesses the feasibility of real-time surgical navigation to plan and guide sequential steps during mandible reconstruction on a series of cadaveric specimens. METHODS: An image-guided surgical (IGS) system was designed including customized mandible and fibula fixation devices with navigation reference frames and an accompanied image-guided software. The mandibular and fibular segmental osteotomies were performed using the IGS in all five cadaveric patients. Procedural time and cephalometric measurements were recorded. RESULTS: Five real-time IGS mandibulectomy and fibular reconstruction were successfully performed. The mean Dice score and Hausdorff-95 distance between the planned and actual mandible reconstructions was 0.8 ± 0.08 and 7.29 ± 4.81 mm, respectively. Intercoronoid width, interangle width, and mandible projection differences were 1.15 ± 1.17 mm, 0.9 ± 0.56 mm, and 1.47 ± 1.62 mm, respectively. CONCLUSION: This study presents the first demonstration of a comprehensive image-guided workflow for mandibulectomy and fibular flap reconstruction on cadaveric specimens and resulted in adequate cephalometric accuracy.

Radiotherapy Versus Transoral Robotic Surgery for Oropharyngeal Squamous Cell Carcinoma: Final Results of the ORATOR Randomized Trial.

Radiotherapy (RT) and transoral robotic surgery (TORS) are both curative-intent treatment options for oropharyngeal squamous cell carcinoma (OPSCC). Herein, we report the final outcomes of the ORATOR trial comparing these modalities, 5 years after enrollment completion. We randomly assigned 68 patients with T1-2N0-2 OPSCC to RT (with chemotherapy if node-positive) versus TORS plus neck dissection (± adjuvant RT/chemoradiation). The primary end point was swallowing quality of life (QOL) assessed with the MD Anderson Dysphagia Inventory (MDADI). Secondary end points included overall and progression-free survival (OS, PFS), adverse events (AEs), and other QOL metrics. The primary end point has been previously reported (Nichols 2019). In this report, the median follow-up was 5.1 years (IQR, 5.0-5.3 years). MDADI total scores converged by 5 years and were not significantly different across the follow-up period (P = .11). EORTC QLQ-C30 and H&N35 scores demonstrated differing profiles, including worse dry mouth in the RT arm (P = .032) and worse pain in the TORS arm (P = .002). Grade 2-5 AE rates did not differ between arms (91% [n = 31] v 97% [n = 33] respectively, P = .61), with more neutropenia and hearing loss in the RT arm, and more dysphagia and other pain in the TORS arm based on grades 2-5 (all P < .05). There were no differences in OS or PFS. In conclusion, toxicity and QOL profiles differ in some domains between RT and TORS, but oncologic outcomes were excellent in both arms. Choice of treatment should remain a shared decision between the patient and their providers.

Abnormal p53 Immunohistochemical Patterns Are Associated with Regional Lymph Node Metastasis in Oral Cavity Squamous Cell Carcinoma at Time of Surgery.

Most (60%-80%) of the oral cavity invasive squamous cell carcinoma (OSCC) demonstrate molecular alterations in TP53. The presence of TP53 mutations in multiple organ systems has been associated with a more aggressive clinical course. This study aimed to classify OSCC into p53 wild-type OSCC and p53-abnormal OSCC using p53 immunohistochemistry and to determine if abnormal p53 status correlates with a higher risk of lymph node metastasis at the time of surgery. A total of 101 patients with OSCC resection and cervical lymph node dissection were identified. p53 immunohistochemistry was performed for all cases and scored into p53 wild-type (p53-HPV: midepithelial/basal sparing, markedly reduced [null-like]/basal sparing; p53-conventional: scattered basal, patchy basal/parabasal) and p53-abnormal (overexpression basal/parabasal only, overexpression basal/parabasal to diffuse, null, and cytoplasmic) patterns. p16 immunohistochemistry and high-risk HPV RNA in situ hybridization were used to confirm the HPV status in cases showing midepithelial/basal sparing or markedly reduced (null-like)/basal sparing pattern. Logistic regression analysis was performed to investigate the association of p53 status, tumor size, depth of invasion, and pT stage against lymph node status. We identified 22 cases with p53 wild-type patterns (16 p53-conventional, 6 p53-HPV) and 79 cases with p53-abnormal patterns. Two of 22 p53 wild-type cases had positive lymph nodes (1 p53-conventional, 1 p53-HPV), whereas 40 of 79 p53-abnormal cases had positive lymph nodes (P < .001). Multivariate analysis showed that p53-abnormal pattern was an independent risk factor associated with positive node(s) with an odds ratio of 8.12 (95% CI, 2.10-53.78; P = .008). p53-Abnormal OSCCs were significantly more likely to be associated with positive lymph node status than p53 wild-type OSCCs at the time of surgery. Further investigation with long-term follow-up is required to determine its clinical application before surgery planning.

Donor site morbidity after scapula free flap surgery of head and neck reconstruction: A systematic review and meta-analysis.

BACKGROUND: The scapula free flap is becoming increasingly more utilized in head and neck reconstruction due to its natural geometry and soft tissue versatility. This study reviews the incidence rate, risk factors, and treatments of complications of scapula donor site morbidity. METHODS: A review was performed for articles published between October 1990 and November 2022 in Medline (OVID), PubMed, Web of Science, and CENTRAL. After screening, 24 articles meeting the criteria were included. RESULTS: Overall, 660 head and neck surgeries with the scapula donor bone across 24 studies were included. Twenty studies of 612 scapula free flaps reported a pooled postoperative complication rate of 10.7%, with no major complications. Seven studies of 199 scapula reconstructions showed a mean Disability of Arm, Shoulder and Hand (DASH) score of 14.39/100. CONCLUSION: With its low rate of morbidity, the scapula flap presents itself as a good alternative for patients at risk for poor healing.

Predicting Tracheostomy Need on Admission to the Intensive Care Unit-A Multicenter Machine Learning Analysis.

OBJECTIVE: It is difficult to predict which mechanically ventilated patients will ultimately require a tracheostomy which further predisposes them to unnecessary spontaneous breathing trials, additional time on the ventilator, increased costs, and further ventilation-related complications such as subglottic stenosis. In this study, we aimed to develop a machine learning tool to predict which patients need a tracheostomy at the onset of admission to the intensive care unit (ICU). STUDY DESIGN: Retrospective Cohort Study. SETTING: Multicenter Study of 335 Intensive Care Units between 2014 and 2015. METHODS: The eICU Collaborative Research Database (eICU-CRD) was utilized to obtain the patient cohort. Inclusion criteria included: (1) Age >18 years and (2) ICU admission requiring mechanical ventilation. The primary outcome of interest included tracheostomy assessed via a binary classification model. Models included logistic regression (LR), random forest (RF), and Extreme Gradient Boosting (XGBoost). RESULTS: Of 38,508 invasively mechanically ventilated patients, 1605 patients underwent a tracheostomy. The XGBoost, RF, and LR models had fair performances at an AUROC 0.794, 0.780, and 0.775 respectively. Limiting the XGBoost model to 20 features out of 331, a minimal reduction in performance was observed with an AUROC of 0.778. Using Shapley Additive Explanations, the top features were an admission diagnosis of pneumonia or sepsis and comorbidity of chronic respiratory failure. CONCLUSIONS: Our machine learning model accurately predicts the probability that a patient will eventually require a tracheostomy upon ICU admission, and upon prospective validation, we have the potential to institute earlier interventions and reduce the complications of prolonged ventilation.

Enabling extracorporeal ultrasound imaging with the da Vinci robot for transoral robotic surgery: a feasibility study.

PURPOSE: Transoral robotic surgery (TORS) is a challenging procedure due to its small workspace and complex anatomy. Ultrasound (US) image guidance has the potential to improve surgical outcomes, but an appropriate method for US probe manipulation has not been defined. This study evaluates using an additional robotic (4th) arm on the da Vinci Surgical System to perform extracorporeal US scanning for image guidance in TORS. METHODS: A stereoscopic imaging system and da Vinci-compatible US probe attachment were developed to enable control of the extracorporeal US probe from the surgeon console. The prototype was compared to freehand US by nine operators in three tasks on a healthy volunteer: (1) identification of the common carotid artery, (2) carotid artery scanning, and (3) identification of the submandibular gland. Operator workload and user experience were evaluated using a questionnaire. RESULTS: The robotic US tasks took longer than freehand US tasks (2.09x longer; p = 0.001 ) and had higher operator workload (2.12x higher; p = 0.004 ). However, operator-rated performance was closer (avg robotic/avg freehand = 0.66; p = 0.017 ), and scanning performance measured by MRI-US average Hausdorff distance provided no statistically significant difference. CONCLUSION: Extracorporeal US scanning for intraoperative US image guidance is a convenient approach for providing the surgeon direct control over the US image plane during TORS, with little modification to the existing operating room workflow. Although more time-consuming and higher operator workload, several methods have been identified to address these limitations.

Outcomes of Radial Forearm Free Flap Closure With Split-Thickness Skin Graft Versus Primary Closure.

BACKGROUND: This study compares patient-reported functional and aesthetic outcomes of split-thickness skin graft (STSG) versus hatchet flap closure of radial forearm free flap (RFFF) donor site. METHODS: Patients with RFFF (2015-2020) were retrospectively identified. Those willing to participate in patient-reported outcomes (PRO) filled out Patient-Observer Scar Assessment Scale (POSAS) and Michigan Hand Outcome Questionnaire (MHOQ). RESULTS: 198 patients met our inclusion criteria and 81 participated in PRO. There was a higher rate of tendon exposure in STSG versus hatchet flap (11 vs. 1, p = 0.0019), but a lower rate of skin necrosis (5 vs. 16, p = 0.0190) and epidermolysis (1 vs. 12, p = 0.0028). Scar quality in STSG was superior to hatchet flap in all domains of POSAS. MHOQ scores were similar between both groups with no statistical difference in overall scores (p = 0.2165). CONCLUSIONS: STSG appeared to have less compromise in activities of daily living, better satisfaction and improved scar quality than hatchet flap, but a higher rate of tendon exposure. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:4266-4273, 2024.

140-year history of pharyngoesophageal reconstruction.

OBJECTIVE: For over a century, circumferential pharyngoesophageal junction reconstruction posed significant surgical challenges. This review aims to provide a narrative history of pharyngoesophageal junction reconstruction from early surgical innovations to the advent of modern free-flap procedures. METHODS: The review encompasses three segments: (1) local and/or locoregional flaps, (2) visceral transposition flaps, and (3) free-tissue transfer, focusing on the interplay between pharyngoesophageal junction reconstruction and prevalent surgical trends. RESULTS: Before 1960, Mikulicz-Radecki's flaps and the Wookey technique prevailed for circumferential pharyngoesophageal junction reconstruction. Gastric pull-up and colonic interposition were favoured visceral techniques in the 1960s-1990s. Concurrently, deltopectoral and pectoralis major flaps were the preferred cutaneous methods. Free flaps (radial forearm, anterolateral thigh) revolutionised reconstructions in the late 1980s, yet gastric pull-up and free jejunal transfer remain in selective use. CONCLUSIONS: Numerous pharyngoesophageal junction reconstructive methods have been trialled in the last century. Despite significant advancements in free-flap reconstruction, some older methods are still in use for challenging clinical situations.

Cost-Effectiveness of the ACR TIRADS Compared to the ATA 2015 Risk Stratification Systems in the Evaluation of Incidental Thyroid Nodules.

RATIONALE AND OBJECTIVES: Thyroid nodules are a common incidental imaging finding and prone to overdiagnosis. Several risk stratification systems have been developed to reduce unnecessary work-up, with two of the most utilized including the American Thyroid Association 2015 (ATA2015) and the newer American College of Radiology Thyroid Imaging, Reporting and Data System (TIRADS) guidelines. The purpose of this study is to evaluate the cost-effectiveness of the ATA2015 versus the TIRADS guidelines in the management of incidental thyroid nodules. METHODS: A cost-utility analysis was conducted using decision tree modeling, evaluating adult patients with incidental thyroid nodules < 4 cm. Model inputs were populated using published literature, observational data, and expert opinion. Single-payer perspective, Canadian dollar currency, five-year time horizon, willingness to pay (WTP) threshold of $50,000, and discount rate of 1.5% per annum were utilized. Scenario, deterministic and probabilistic sensitivity analyses were performed. The primary outcome was the incremental cost-effectiveness ratio (ICER) expressed as incremental cost per quality-adjusted life year (QALY) gained. RESULTS: For the base case scenario, TIRADS dominated the ATA2015 strategy by a slim margin, producing 0.005 more QALYs at $25 less cost. Results were sensitive to the malignancy rate of biopsy and the utilities of a patient with a benign nodule/subclinical malignancy or under surveillance. Probabilistic sensitivity analysis showed that TIRADS was the more cost-effective option 79.7% of the time. CONCLUSION: The TIRADS guidelines may be the more cost-effective strategy by a small margin compared to ATA2015 in most scenarios when used to risk stratify incidental thyroid nodules.

To what extent can mastication functionality be restored following mandibular reconstruction surgery? A computer modeling approach.

STATEMENT OF PROBLEM: Advanced cases of head and neck cancer involving the mandible often require surgical removal of diseased sections and subsequent replacement with donor bone. During the procedure, the surgeon must make decisions regarding which bones or tissues to resect. This requires balancing tradeoffs related to issues such as surgical access and post-operative function; however, the latter is often difficult to predict, especially given that long-term functionality also depends on the impact of post-operative rehabilitation programs. PURPOSE: To assist in surgical decision-making, we present an approach for estimating the effects of reconstruction on key aspects of post-operative mandible function. MATERIAL AND METHODS: We develop dynamic biomechanical models of the reconstructed mandible considering different defect types and validate them using literature data. We use these models to estimate the degree of functionality that might be achieved following post-operative rehabilitation. RESULTS: We find significant potential for restoring mandibular functionality, even in cases involving large defects. This entails an average trajectory error below 2 mm, bite force comparable to a healthy individual, improved condyle mobility, and a muscle activation change capped at a maximum of 20%. CONCLUSION: These results suggest significant potential for adaptability in the masticatory system and improved post-operative rehabilitation, leading to greater restoration of jaw function.

Evaluating the benefit of virtual surgical planning on bony union rates in head and neck reconstructive surgery.

OBJECTIVES: Virtual surgical planning (VSP) has gained acceptance because of its benefits in obtaining adequate resection, achieving cephalometric accuracy, and reducing operative time. The aim of this study is to compare the rate of union between VSP and free-hand surgery (FHS), identify predictors of non-union and evaluate the difference in operative time. METHODS: Post-operative CT were retrospectively reviewed for 123 patients who underwent maxillary or mandibular reconstruction between 2014 and 2021 using either VSP or FHS. Each apposition was graded as complete, partial or non-union. The rate of union, risk difference and inter-rater reliability were calculated. The difference in operative time was assessed. Predictors of non-union were identified using logistic regression. RESULTS: A total of 326 appositions were graded (VSP n = 150; FHS n = 176). The rates of complete and partial union were higher with VSP than FHS (74.7% vs. 65.3%; 18% vs. 15.9%, respectively, p = 0.01). Non-union was found at a higher rate with FHS than with VSP (18.7% vs. 7.3%). The non-union risk difference was 11.4. FHS, major complications and apposition at the native bone were predictors of non-union (OR 2.9, p = 0.02; OR 3.4, p = 0.01; OR 2.5, p = 0.05, respectively). The mean surgical time was shorter with VSP than with FHS (265.3 vs. 381.5 min, p < 0.001). The inter-rater agreement was high (k = 0.85; ICC = 0.86). CONCLUSION: VSP demonstrated significantly higher bony union rates and shorter operative time. FHS, development of major complications and apposition with native bone correlated with non-union.

Incidence and complications of hypothyroidism postlaryngectomy: A systematic review and meta-analysis.

BACKGROUND: Hypothyroidism is common postlaryngectomy and is associated with laryngectomy-specific complications. The objective of this study is to determine the incidence and predictors of hypothyroidism postlaryngectomy and its associated complications. METHODS: Systematic review, data extraction, and meta-analyses were performed following the PRISMA protocol. Six databases were searched for studies reporting on postlaryngectomy thyroid status with incidence, risk factors, management, or complications. RESULTS: Fifty-one studies with 6333 patients were included. The pooled incidence of postlaryngectomy hypothyroidism is 49% (CI 42%-57%). Subgroup analysis showed postlaryngectomy hypothyroidism rates significantly correlated with hemithyroidectomy and radiotherapy. Patients who underwent laryngectomy, hemithyroidectomy, and radiotherapy had a 65% (CI 59%-71%) rate of hypothyroidism; laryngectomy and hemithyroidectomy 46% (CI 33%-60%); laryngectomy and radiotherapy 26% (CI 19%-35%); and laryngectomy alone 11% (CI 4%-27%) (p < 0.001). CONCLUSIONS: Laryngectomized patients with partial thyroidectomy or radiation therapy are at significant risk of postoperative hypothyroidism. Evidence-based protocols for early detection and (prophylactic) treatment should be established.

Computational models and their applications in biomechanical analysis of mandibular reconstruction surgery.

Advanced head and neck cancers involving the mandible often require surgical removal of the diseased parts and replacement with donor bone or prosthesis to recreate the form and function of the premorbid mandible. The degree to which this reconstruction successfully replicates key geometric features of the original bone critically affects the cosmetic and functional outcomes of speaking, chewing, and breathing. With advancements in computational power, biomechanical modeling has emerged as a prevalent tool for predicting the functional outcomes of the masticatory system and evaluating the effectiveness of reconstruction procedures in patients undergoing mandibular reconstruction surgery. These models offer cost-effective and patient-specific treatment tailored to the needs of individuals. To underscore the significance of biomechanical modeling, we conducted a review of 66 studies that utilized computational models in the biomechanical analysis of mandibular reconstruction surgery. The majority of these studies employed finite element method (FEM) in their approach; therefore, a detailed investigation of FEM has also been provided. Additionally, we categorized these studies based on the main components analyzed, including bone flaps, plates/screws, and prostheses, as well as their design and material composition.

Patient-Reported Decisional Regret After Operative Otolaryngology Procedures: A Scoping Review.

OBJECTIVE: To review the published literature on decisional regret in adult patients undergoing operative otolaryngology procedures. The primary outcome was decisional regret scale (DRS) scores. DRS scores of 0 indicate no regret, 1-25 mild regret, and >25 moderate to strong/severe regret. DATA SOURCES: A comprehensive librarian-designed strategy was used to search MEDLINE, Embase, and CINAHL from inception to September 2023. REVIEW METHODS: Inclusion criteria consisted of English-language studies of adult patients who underwent operative otolaryngology treatments and reported DRS scores. Data was extracted by two independent reviewers. Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines were followed. Oxford Centre's Levels of Evidence were used for quality assessment. RESULTS: In total, 6306 studies were screened by two independent reviewers; 13 studies were included after full-text analysis. Subspecialties comprised: Head and neck (10), endocrine (1), general (1), and rhinology (1). The DRS results of the included studies spanned a mean range of 10.1-23.9 or a median range of 0-20.0. There was a trend toward more decisional regret after large head and neck procedures or when patients underwent multiple treatment modalities. Depression, anxiety, and patient-reported quality of life measures were all correlated with decisional regret. Oxford Centre's Levels of Evidence ranged from 2 to 4. CONCLUSION: This is the first comprehensive review of decisional regret in otolaryngology. The majority of patients had no or mild (DRS <25) decisional regret after otolaryngology treatments. Future research on pre-operative counseling and shared decision-making to further minimize patient decisional regret is warranted. LEVEL OF EVIDENCE: N/A Laryngoscope, 2023.

Identification of a serum-based microRNA signature that detects recurrent oral squamous cell carcinoma before it is clinically evident.

BACKGROUND: Survival rates for oral squamous cell carcinoma (OSCC) have remained poor for decades, a fact largely attributable to late-stage diagnoses and high recurrence rates. We report analysis of serum miRNA expression in samples from patients with high-risk oral lesions (HRL, including OSCC/carcinoma in situ lesions) and healthy non-cancer controls, with the aim of non-invasively detecting primary or recurrent disease before it is clinically evident. METHODS: Discovery, test, and validation sets were defined from a total of 468 serum samples (305 HRL and 163 control samples). Samples were analysed using multiple qRT-PCR platforms. RESULTS: A two-miRNA classifier comprised of miR-125b-5p and miR-342-3p was defined following discovery and test analyses. Analysis in an independent validation cohort reported sensitivity and specificity of ~74% for this classifier. Significantly, when this classifier was applied to serial serum samples taken from patients both before treatment and during post-treatment surveillance, it identified recurrence an average of 15 months prior to clinical presentation. CONCLUSIONS: These results indicate this serum miRNA classifier is effective as a simple, non-invasive monitoring tool for earlier detection of recurrent disease when lesions are typically smaller and amenable to a wider array of treatment options to improve survival.

Decisional regret, symptom burden, and quality of life following transoral robotic surgery for oropharyngeal cancer.

BACKGROUND: Transoral robotic surgery (TORS) has equivalent oncologic control to radiotherapy with potential for improved quality of life (QOL) and lower patient-reported decisional regret. METHODS: Cross-sectional study between 2016 and 2021 of TORS patients with early-stage oropharyngeal squamous cell carcinoma who completed the Decision Regret Scale (DRS), M. D. Anderson Dysphagia Inventory (MDADI), and University of Washington Quality of Life (UW-QOL). The median time from treatment to questionnaire completion was 1.8 years (IQR 1.4-3.3, range 1.0-5.6). RESULTS: Of 65 patients, 84.6% expressed no or mild decisional regret. Regret was not associated with clinical parameters or adjuvant treatment but was correlated with MDADI (τavg = -0.23, p < 0.001) and UW-QOL (τavg = -0.27, p < 0.001). Worse MDADI was associated with older age and worse UW-QOL was associated with multi-site operation and shorter time to survey. CONCLUSIONS: Overall, the TORS cohort expressed very limited decisional regret. DRS scores were unaffected by clinicodemographics or additional adjuvant therapies, but decision regret was correlated with worse QOL and worse swallowing.

Individualized risk assessment of distant metastases in oral cavity carcinoma: a validated predictive-score model.

BACKGROUND: We aimed to develop and validate a risk-scoring system for distant metastases (DMs) in oral cavity carcinoma (OCC). METHODS: Patients with OCC who were treated at 4 tertiary cancer institutions with curative surgery with or without postoperative radiation/chemoradiation therapy were randomly assigned to discovery or validation cohorts (3:2 ratio). Cases were staged on the basis of tumor, node, and metastasis staging according to the eighth edition of the American Joint Committee on Cancer/Union for International Cancer Control guidelines. Predictors of DMs on multivariable analysis in the discovery cohort were used to develop a risk-score model and classify patients into risk groups. The utility of the risk classification was evaluated in the validation cohort. RESULTS: Overall, 2749 patients were analyzed. Predictors (risk score coefficient) of DMs in the discovery cohort were the following: pathological stage (p)T3-4 (0.4), pN+ (N1: 0.8; N2: 1.0; N3: 1.5), histologic grade (G) 3 (G3, 0.7), and lymphovascular invasion (0.4). The DM risk groups were defined by the sum of the following risk score coefficients: high (>1.7), intermediate (0.7-1.7), and standard risk (<0.7). The 5-year DM rates (high/intermediate/standard risk groups) were 30%/15%/4% in the discovery cohort (C-index = 0.79) and 35%/16%/5% in the validation cohort, respectively (C-index = 0.77; both P < .001). In the whole cohort, this predictive model showed excellent discriminative ability in predicting DMs without locoregional failure (29%/11%/1%), later (>2 year) DMs (11%/4%/2%), and DMs in patients treated with surgery (20%/12%/5%), postoperative radiation therapy (34%/17%/4%), and postoperative chemoradiation therapy (39%/18%/7%) (all P < .001). The 5-year overall survival rates in the overall cohort were 25%/51%/67% (P < .001). CONCLUSIONS: Patients at higher risk for DMs were identified by use of a predictive-score model for DMs that included pT3-4, pN1/2/3, G3, and lymphovascular invasion. Identified patients may be evaluated for individualized risk-adaptive treatment escalation and/or surveillance strategies.

Treatment of Laryngeal Verrucous Carcinoma: 28-Year Retrospective Cohort Study and Literature Review.

Objective: Laryngeal verrucous carcinoma (LVC) comprises 1% to 4% of all laryngeal tumors. Although controversial, surgery has been the mainstay of treatment, due to concern about anaplastic transformation with radiotherapy. We aimed to study LVC patients to identify treatment patterns for primary and recurrent diseases. Study Design: Retrospective cohort study. Setting: Tertiary referral center. Methods: Patients with a pathological diagnosis of LVC treated over a 28-year period were included. Baseline demographics, and treatment outcome measures including 5-year laryngeal preservation rates (LPR), overall survival (OS), and recurrence-free survival (RFS) were included. A literature review of published studies within the same study period was also completed. Results: Thirty-two patients were included in the analysis (median age 61.5 years, 93.8% [30/32] male). Twenty-three patients had T1 disease, and 9 had T2 disease with no evidence of regional or metastatic disease. The most common presenting symptom was hoarseness (93.8%) and the majority within the glottis 81.3% (26/32). Twenty-nine patients underwent primary surgery only (28 local excisions, 1 vertical partial laryngectomy) meanwhile 3 underwent local excision with postoperative radiotherapy. LPR, OS, and RFS at 5 years were 95.8%, 90.1%, and 80.6%, respectively. Our literature review identified 23 previous studies, mostly single-institution retrospective case series. Our study was the largest Canadian study in the literature to date. Conclusion: All LVC patients were treated with primary surgery, consistent with the current literature with excellent 5-year OS and LPR. There was no consensus on the treatment of recurrent disease. Future prospective multicenter studies are warranted to further study this rare disease population.

Towards transcervical ultrasound image guidance for transoral robotic surgery.

PURPOSE: Trans-oral robotic surgery (TORS) using the da Vinci surgical robot is a new minimally-invasive surgery method to treat oropharyngeal tumors, but it is a challenging operation. Augmented reality (AR) based on intra-operative ultrasound (US) has the potential to enhance the visualization of the anatomy and cancerous tumors to provide additional tools for decision-making in surgery. METHODS: We propose a US-guided AR system for TORS, with the transducer placed on the neck for a transcervical view. Firstly, we perform a novel MRI-to-transcervical 3D US registration study, comprising (i) preoperative MRI to preoperative US registration, and (ii) preoperative to intraoperative US registration to account for tissue deformation due to retraction. Secondly, we develop a US-robot calibration method with an optical tracker and demonstrate its use in an AR system that displays anatomy models in the surgeon's console in real-time. RESULTS: Our AR system achieves a projection error from the US to the stereo cameras of 27.14 and 26.03 pixels (image is 540[Formula: see text]960) in a water bath experiment. The average target registration error (TRE) for MRI to 3D US is 8.90 mm for the 3D US transducer and 5.85 mm for freehand 3D US, and the TRE for pre-intra operative US registration is 7.90 mm. CONCLUSION: We demonstrate the feasibility of each component of the first complete pipeline for MRI-US-robot-patient registration for a proof-of-concept transcervical US-guided AR system for TORS. Our results show that trans-cervical 3D US is a promising technique for TORS image guidance.