Reconstruction in open anterior skull base surgery: A review and algorithmic approach.

PURPOSE: Defects resulting from open resection of anterior skull base neoplasms are difficult to reconstruct. Our objective was to review the literature and describe an evidence-based algorithm that can guide surgeons reconstructing anterior skull base defects. METHODS: A research librarian designed database search strategies. Two investigators independently reviewed the resulting abstracts and full text articles. Studies on reconstruction after open anterior skull base resection were included. Studies of lateral and posterior skull base reconstruction, endoscopic endonasal surgery, traumatic and congenital reconstruction were excluded. Based on the review, a reconstructive algorithm was proposed. RESULTS: The search strategy identified 603 unique abstracts. 53 articles were included. Adjacent subsites resected, defect size, radiotherapy history, and contraindications to free tissue transfer were identified as key factors influencing decision making and were used to develop the algorithm. Discussion of the reconstructive ladder as it applies to skull base reconstruction and consideration of patient specific factors are reviewed. Patients with a prior history of radiotherapy or with simultaneous resection of multiple anatomic subsites adjacent to the anterior skull base will likely benefit from free tissue transfer. CONCLUSIONS: Reconstruction of anterior skull base defects requires knowledge of the available reconstructive techniques and consideration of defect-specific and patient-specific factors.

Transoral Thyroidectomy: Safety and Outcomes of 200 Consecutive North American Cases.

BACKGROUND: North American adoption of the transoral endoscopic thyroidectomy vestibular approach (TOETVA) has been limited due to concerns regarding the generalizability of published outcomes, as data are predominantly from Asian cohorts with a different body habitus. We describe our experience with TOETVA in a North American population in the context of the conventional transcervical approach thyroidectomy (TCA). STUDY DESIGN: Cases of TOETVA and TCA were reviewed from August 2017 to March 2020 at a tertiary care center. Outcomes included operative time, major (permanent recurrent laryngeal nerve (RLN) injury, permanent hypoparathyroidism, hematoma, conversion to open surgery), and minor complications. The TOETVA cohort was stratified into body mass index (BMI) classes of underweight/normal < 25 kg/m2, overweight 25-29.9 kg/m2, and obese ≥ 30 kg/m2 for comparative analysis. Multivariable logistic regression analyses were performed for odds of cumulative complication. RESULTS: Two hundred TOETVA and 333 TCA cases were included. There was no difference in incidence of major complications between the TOETVA and TCA cohorts (1.5% vs. 2.1%, p = 0.75). No difference was found in the rate of temporary RLN injury (4.5% vs. 2.1%, p = 0.124) or temporary hypoparathyroidism (18.2% vs. 12.5%, p = 0.163) for TOETVA and TCA, respectively. Surgical technique (TOETVA vs TCA) did not alter the odds of cumulative complication (OR 0.69 95% CI [0.26-1.85]) on logistic regression analysis. In the TOETVA cohort, higher BMI did not lead to a significantly greater odds of cumulative complication, 0.52 (95% CI [0.17-1.58]) and 1.69 (95% CI [0.74-3.88]) for the overweight and obese groups, respectively. CONCLUSION: TOETVA can be performed in a North American patient population without a difference in odds of complication compared to TCA. Higher BMI is not associated with greater likelihood of complication with TOETVA.

Structural and mechanistic insights into guanylylation of RNA-splicing ligase RtcB joining RNA between 3'-terminal phosphate and 5'-OH.

The RtcB protein has recently been identified as a 3'-phosphate RNA ligase that directly joins an RNA strand ending with a 2',3'-cyclic phosphate to the 5'-hydroxyl group of another RNA strand in a GTP/Mn(2+)-dependent reaction. Here, we report two crystal structures of Pyrococcus horikoshii RNA-splicing ligase RtcB in complex with Mn(2+) alone (RtcB/ Mn(2+)) and together with a covalently bound GMP (RtcB-GMP/Mn(2+)). The RtcB/ Mn(2+) structure (at 1.6 Å resolution) shows two Mn(2+) ions at the active site, and an array of sulfate ions nearby that indicate the binding sites of the RNA phosphate backbone. The structure of the RtcB-GMP/Mn(2+) complex (at 2.3 Å resolution) reveals the detailed geometry of guanylylation of histidine 404. The critical roles of the key residues involved in the binding of the two Mn(2+) ions, the four sulfates, and GMP are validated in extensive mutagenesis and biochemical experiments, which also provide a thorough characterization for the three steps of the RtcB ligation pathway: (i) guanylylation of the enzyme, (ii) guanylyl-transfer to the RNA substrate, and (iii) overall ligation. These results demonstrate that the enzyme's substrate-induced GTP binding site and the putative reactive RNA ends are in the vicinity of the binuclear Mn(2+) active center, which provides detailed insight into how the enzyme-bound GMP is tansferred to the 3'-phosphate of the RNA substrate for activation and subsequent nucleophilic attack by the 5'-hydroxyl of the second RNA substrate, resulting in the ligated product and release of GMP.

Factors Impacting Provider Treatment Decision-Making in Early Glottic Cancer.

OBJECTIVES: Transoral laser microsurgery (TLMS) and radiotherapy (XRT) are mainstays of treatment for early glottic carcinoma (EGC). Here, we investigated case-dependent provider treatment preferences and identify factors which impact decision-making in EGC. METHODS: This cross-sectional survey of laryngologists, head-and-neck surgeons, and radiation oncologists presented five diagrammatic cases of progressively advanced EGC (T1/2, N0). Respondents indicated preference for TLMS or XRT and ranked factors which influenced their recommendation for each case. Analysis utilized descriptive statistics, Fischer's exact tests, and Kruskal-Wallis tests for nonparametric data. RESULTS: A total of 141 complete responses (69.5% laryngologists) were received. Most respondents practiced in academic settings (93.5%) and within multidisciplinary teams (94.0%). Anterior commissure involvement was the most important a priori tumor factor for case-independent treatment recommendation (Likert Scale: 4.22/5), followed by Laterality (Likert Scale: 4.02/5). Across all specialties, TLMS was recommended for unilateral T1a lesions. Laryngologists continued recommending TLMS in T2 lesions (41.0%) more than head-and-neck surgeons (5.0%) and radiation oncologists (0.0%). Across all cases, survival and voice outcomes were the most important clinical factors impacting treatment decisions. Radiation oncologists weighed voice more heavily than laryngologists in more complex presentations of EGC (rank: 1.6 vs. 2.7, Kruskall-Wallis: p < 0.05). CONCLUSIONS: In more complex clinical presentations of EGC, preference for TLMS compared to XRT differed across specialists, despite similar rankings of factors driving these treatment recommendations. This may be driven by differing experiences and viewpoints on case-dependent voice outcomes following TLMS versus XRT, suggesting a need for increased understanding of how tumor location and depth impact voice outcomes. LEVEL OF EVIDENCE: 5 Laryngoscope, 134:3686-3694, 2024.

Cost comparison between open thyroid lobectomy and radiofrequency ablation for management of thyroid nodules.

BACKGROUND: There is an increasing array of treatment options for addressing clinically significant thyroid nodules, including radiofrequency ablation (RFA). While effective, the cost compared to alternative approaches has not been well elucidated. METHODS: This study involved a retrospective chart review, focusing on variable direct cost (VDC) of each procedure, from April 2016 to January 2020. We analyzed costs for 53 open lobectomies and 16 RFA procedures. RESULTS: Cost effectiveness depended on the simulated cost of the RFA probe. In comparison to open lobectomy, the VDC to perform RFA was $597 (19%) cheaper when the simulated probe cost was $1500 and $403 (13%) more expensive for a probe cost of $2500. Statistical significance was achieved for both these differences. CONCLUSIONS: If cost per RFA probe can be less than $2100-the break-even dollar amount between open lobectomy and RFA-there would be considerable cost savings for treating thyroid nodules.

Predictive model of operative time in transoral endoscopic thyroidectomy vestibular approach.

BACKGROUND: Transoral Endoscopic Thyroidectomy Vestibular Approach (TOETVA) has demonstrated excellent safety and is receiving wider use in North America. Understanding which factors lead to operative difficulty, as evaluated by operative time (OT), may help to improve safety and refine indications for this procedure. METHODS: Cases of TOETVA performed at our institution were reviewed. Multivariate linear regression was performed using patient demographics, thyroid characteristics, and operative variables to predict OT. RESULTS: A total of 207 cases were included for analysis. A multivariate linear regression model, controlling for age, sex, and BMI, was developed from 104 cases with an R2 of 0.47 (p < 0.001). Cross-validation on 103 remaining cases showed root-mean-square error of 46.37. Total thyroidectomy and lobe size were the only significant predictors (p < 0.001). CONCLUSIONS: We successfully developed a model to predict OT for TOETVA based on preoperative and operative variables. Lobe size, but not BMI, is a significant predictor of OT.

Factors and Outcomes Associated With Temporal Bone Resection for Primary Parotid Malignancy.

OBJECTIVE(S): Although parotid cancer invading into the temporal bone makes up only a small fraction of all parotid cancers, it is more common and relatively understudied compared with primary cancer of the external auditory canal. The objective of this study was to determine what factors are associated with receiving parotidectomy with temporal bone resection (TBR) and the immediate postoperative outcomes. METHODS: We reviewed the National Cancer Database (2004-2015) for patients with primary parotid malignancy who received parotidectomy with or without TBR. Patient demographic, clinical, and perioperative variables were collected and then compared. Multivariate logistic regression was performed to determine factors associated with receiving TBR. RESULTS: We identified 134 patients who received parotidectomy with TBR and 16,595 who received parotidectomy only. Reported in terms of odds ratios (95% confidence interval), our multivariate model showed having surgery at an academic facility (1.91 [1.34-2.71], P < .001), clinical stage III or IV (7.48 [1.65-33.96] and 31.37 [7.61-129.32], P = .009 and P < .001, respectively), histologic grade II to IV (4.36 [1.51-12.57], 4.31 [1.53-12.15], and 6.74 [2.26-20.13], P = .006, .006, and .001, respectively), and adenoid cystic histology (3.23 [2.02-5.17], P < .001) were significantly and independently associated with receiving TBR. There was no significant difference in 30-day readmission, or 30-day or 90-day mortality, but the rate of positive surgical margins was significantly higher in those who underwent TBR. CONCLUSION: Demographic variables are not significant factors for receiving TBR. Tumor characteristics, such as clinical stage and histologic type, and receiving surgical treatment at an academic facility were more strongly associated with receiving TBR. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E2461-E2468, 2021.

The variable direct cost and cost drivers of transoral endoscopic thyroidectomy vestibular approach.

BACKGROUND: As transoral endoscopic thyroidectomy vestibular approach grows in popularity, there is a need for data on cost in order to better characterize its value to patients. To this end, we compared the variable direct cost of transoral endoscopic thyroidectomy vestibular approach and transcervical approach thyroidectomy and determined which factors drive the increased cost for the transoral approach. METHODS: Patients undergoing thyroid lobectomy and total thyroidectomy that met inclusion criteria for transoral endoscopic thyroidectomy vestibular approach, including those patients that opted for management via the transcervical approach, between 8/2016 and 4/2019 were reviewed. The variable direct cost for the surgical encounter was collected and means were compared between the transoral and transcervical cohorts for lobectomy and total thyroidectomy respectively. The operative time independent variable direct cost was similarly compared between cohorts. RESULTS: Out of 238 patients, 118 (50%) were managed via transoral endoscopic thyroidectomy vestibular approach and 120 (50%) were managed via transcervical approach thyroidectomy. Mean variable direct cost, our primary outcome, was $4,455 (SD 1,129, 95% CI: 4,204-4,706) for transoral lobectomy and $3,179 (SD 687, 95% CI: 2,990-3,369) for transcervical lobectomy [t(132.05)=8.09, P<0.001] representing a difference in cost of $1,276 (SD 158, 95% CI: 964-1,587). Mean variable direct cost was $4,681 (SD 829, 95% CI: 4,405-4,957) for transoral total thyroidectomy and $3,645 (SD 876, 95% CI: 3,431-3,858) for transcervical total thyroidectomy [t(79.92)=5.98, P<0.001], representing a difference in cost of $1,036 (SD 173, 95% CI: 691-1,381). Differences in energy devices alone account for $487.53 and $447.96 of the cost differences, respectively. CONCLUSIONS: The differences in mean variable direct cost between transoral endoscopic vestibular approach and transcervical approach for lobectomy and total thyroidectomy were $1276 and $1036 respectively, amounts far less than some believe them to be. This data will be invaluable as we ultimately aim to define the value of transoral endoscopic thyroidectomy vestibular approach.

Simulations and simulators in head and neck endocrine surgery.

Simulations and simulators have become an increasingly important tool in trainee education across many surgical disciplines, particularly for robotic and minimally invasive procedures. Thyroidectomy and parathyroidectomy are common procedures performed across multiple surgical disciplines, however, there is limited literature regarding training models/simulators for these operations. This is despite the advent and growing popularity of remote-access thyroidectomy techniques, where simulators may provide significant value in trainee education and safe implementation. Here we review the literature regarding available simulations/simulators in head and neck endocrine surgery for both conventional transcervical approaches and newer remote-access thyroidectomy techniques.

Pressure Transmission to the Inner Ear by Mastoid Palpation After Transmastoid Surgery for Superior Canal Dehiscence.

OBJECTIVE: To discuss an effect of transmastoid repair of superior semicircular canal dehiscence and its resolution using a mastoid titanium mesh plate. PATIENTS: A 53-year-old woman with a history of superior canal dehiscence syndrome (SCDS) and subsequent transmastoid repair experienced dizziness and a loud, drum-like sound in her repaired ear when touching the ear. Palpating the skin over the mastoid defect reproduced the symptoms and could be observed on binocular microscopy as tympanic membrane deformation synchronous with mastoid palpation. INTERVENTION (S): Surgery to place a titanium mesh cranioplasty plate over the mastoid cavity. MAIN OUTCOME MEASURE (S): Reduction in dizziness and auditory symptoms when palpating the mastoid. RESULTS: In follow-up 2 months after surgery, palpation of the left mastoid no longer results in vertigo or hearing a loud sound. Hearing and vestibular function remained unchanged. CONCLUSIONS: Despite resolution of SCDS symptoms after transmastoid plugging and resurfacing of the superior semicircular canal involving mastoidectomy, patients can be bothered by dizziness and vertigo when pressing on the mastoid soft tissue envelope. This acts like a balloon that, when compressed, changes middle ear pressure and moves the tympanic membrane and can even cause alternobaric vertigo. This can be avoided or resolved by rigidly reconstructing the defect in the mastoid bone.