The effect of fidelity: how expert behavior changes in a virtual reality environment.

OBJECTIVES/HYPOTHESIS: We compare the behavior of expert surgeons operating on the "gold standard" of simulation-the cadaveric temporal bone-against a high-fidelity virtual reality (VR) simulation. We aim to determine whether expert behavior changes within the virtual environment and to understand how the fidelity of simulation affects users' behavior. STUDY DESIGN AND METHODS: Five expert otologists performed cortical mastoidectomy and cochleostomy on a human cadaveric temporal bone and a VR temporal bone simulator. Hand movement and video recordings were used to derive a range of measures, to facilitate an analysis of surgical technique, and to compare expert behavior between the cadaveric and simulator environments. RESULTS: Drilling time was similar across the two environments. Some measures such as total time and burr change count differed predictably due to the ease of switching burrs within the simulator. Surgical strokes were generally longer in distance and duration in VR, but these measures changed proportionally to cadaveric measures across the stages of the procedure. Stroke shape metrics differed, which was attributed to the modeling of burr behavior within the simulator. This will be corrected in future versions. CONCLUSION: Slight differences in drill interaction between a virtual environment and the real world can have measurable effects on surgical technique, particularly in terms of stroke length, duration, and curvature. It is important to understand these effects when designing and implementing surgical training programs based on VR simulation--and when improving the fidelity of VR simulators to facilitate use of a similar technique in both real and simulated situations.

Survival outcomes of patients with advanced oral cavity squamous cell carcinoma treated with multimodal therapy: a multi-institutional analysis.

BACKGROUND: The oral cavity is the most common site for head and neck squamous cell carcinoma. Treatment of advanced stage oral cavity squamous cell carcinoma (OCSCC) has classically involved surgical resection with postoperative adjuvant radiotherapy (S-RT).Despite this aggressive dual modality therapy, the disease outcomes have remained poor. The treatment options expanded in 2004 when two international trials showed the addition of postoperative chemotherapy to radiation improved outcomes. These trials were, however not oral cavity site specific. OBJECTIVE: To assess survival outcomes of advanced OCSCC treated by differing modalities. The primary goal was to determine if the addition of postoperative chemotherapy (S-CRT) improves survival compared to other treatment regimens. METHODS: Demographic, pathologic, treatment, and survival data was obtained from patients diagnosed with OCSCC from 1998-2010 in Alberta, Canada. 222 patients were included in the final analysis from 895 OCSCC patients. Actuarial overall, disease-specific, disease-free, and metastasis-free survivals were estimated with Kaplan-Meier and Cox regression analyses. Patients were grouped by treatment. RESULTS: Patients receiving S-CRT had improved overall, disease-specific, disease-free, and metastasis-free survival compared to S-RT, CRT or RT(p < 0.05). Two and five year estimated overall survival was significantly higher in the S-CRT group at 77 and 58% (p < 0.05), versus S-RT with 55 and 40% rates(p < 0.05). Results were similar for disease-specific, disease-free, and metastasis free survival with S-CRT being favoured. Patients with extracapsular spread (ECS) treated with S-CRT versus S-RT had 55% survival advantage at 5 years (p < 0.05). CONCLUSION: This study shows that adding adjuvant chemotherapy to S-RT improves survival outcomes in advanced OCSCC, especially in patients with ECS.

Neck metastases in oropharyngeal cancer: Necessity and extent of bilateral treatment.

BACKGROUND: Bilateral neck treatment in oropharyngeal squamous cell carcinoma (OPSCC) is controversial. This study determined the rate of bilateral neck metastases in OPSCC and formulated a neck treatment algorithrm for OPSCC. METHODS: In all, 212 consecutive patients with OPSCC underwent ipsilateral level I-V and contralateral I-III or I-V neck dissections. Pathology results were used to identify factors predicting bilateral neck metastases. RESULTS: A total of 171 patients (81%) had ipsilateral and 41 patients (24%) bilateral neck metastases. Multivariate logistic regression found cT4 and ≥cN2a significantly associated with contralateral neck metastases (p < .05). However, tumor site was not predictive (p > .05). High-risk pathology features predicted contralateral neck disease (p < .05). cN0 and cN1 necks were unlikely to harbor disease in level V (<5%). Both 2- and 5-year contralateral neck recurrence rates were 1% and 2%. CONCLUSIONS: Bilateral neck disease in OPSCC is more common than once thought. Patients with OPSCC with cT4 or cN2a+ would benefit from bilateral neck treatment. Posttreatment high-risk features should guide treatment escalation.

Surgery for neurofibromatosis 2.

PURPOSE OF REVIEW: This study reviews the latest literature relating to the surgical treatment of otologic manifestations in patients with neurofibromatosis 2 (NF2). The emphasis is on vestibular and other schwannomas. We review surgical approaches, including hearing preservation and nonhearing preservation surgery, as well as outcomes, including hearing and facial nerve function. RECENT FINDINGS: Vestibular schwannomas in NF2 are difficult to manage because they are bilateral and may be aggressive. Depending on hearing status, tumor size and the presence or absence of compressive symptoms, these tumors can be managed by observation, radiotherapy or surgery. The goal is to maximize the years of useful hearing. Surgery may attempt to preserve hearing or aim for complete tumor resection and preservation of facial nerve function. SUMMARY: The natural history of vestibular schwannomas and other tumors in patients with NF2 is difficult to predict. The decision between observation and either medical or surgical intervention, as well as the choice of surgical procedure, depend on patient factors and preferences and on the experience of the treating center.

Can Uhear me now? Validation of an iPod-based hearing loss screening test.

OBJECTIVE: To evaluate the uHear iPod-based application as a test for hearing loss. METHODS: We recruited 100 adult participants through a single otology practice. Patients with otorrhea and cognitive impairment were excluded. All patients completed the uHear test in the clinic and in the sound booth and underwent a standard audiogram by the same audiologist. We compared the results of the uHear test to the standard audiogram. RESULTS: The uHear was able to correctly diagnose the presence of hearing loss (pure-tone average [PTA] > 40 dB) with a sensitivity of 98% (95% CI = 89-100), a specificity of 82% (95% CI = 75-88), and a positive likelihood ratio of 9 (95% CI = 6.0-16). Compared to the audiogram, the uHear overestimated the PTA among all ears by 14 dB in the clinic and by 8 dB in the sound booth (p < .0001). Compared to the audiogram, the uHear overestimated the PTA among ears with hearing loss by 6 dB in the clinic and by 4 dB in the sound booth. CONCLUSIONS: The uHear application is a reasonable screening test to rule out moderate hearing loss (PTA > 40 dB) and and is valid at quantifying the degree of hearing loss in patients known to have abnormal hearing.

Systematic review of the platysma myocutaneous flap for head and neck reconstruction.

OBJECTIVES: To systematically review and quantify complication rates and to identify preoperative factors among patients who underwent platysma myocutaneous flap reconstruction for head and neck cancer. DESIGN: This study analyzed 190 patients in 16 case series published between 1982 and 2002. Funnel plots, contingency tables, and chi(2) analyses were used to minimize bias and heterogeneity among the studies. Logistic regression models were used to quantify the associations between preoperative factors (age, sex, T stage, prior radiation therapy, and recipient site) and complications (skin loss or necrosis, fistula, dehiscence, hematoma, and infection) at different recipient sites (floor of mouth, alveolar ridge, pharyngeal wall, buccal mucosa, tongue or tongue base, and tonsil). SETTING: Academic research. PATIENTS: Patients described in the literature with head and neck surgery who underwent platysma flap reconstruction. MAIN OUTCOME MEASURES: Results of logistic regression analyses. RESULTS: Seventy-one patients (37%) developed a complication, ranging from 20% at the buccal mucosa to 55% at the tonsil and at the alveolar ridge. Major complications (ie, those requiring further surgery) occurred in 5% of patients. The most common complication was skin loss or necrosis, occurring in 25% of patients. Postoperative complications were not associated with age or sex but were associated with recipient site and tumor stage. Overall, complications were 0.3 (95% confidence interval [CI], 0.1-1.1) times less common at the buccal mucosa than at other recipient sites. Hematomas were 18.8 (95% CI, 1.6-217) times more common at the buccal mucosa. Infections were 20.0 (95% CI, 1.1-350) times more common at the pharyngeal wall. Major complications were 4.6 (95% CI, 0.9-23.5) times more likely, and fistulas were 9.2 (95% CI, 2.0-43.1) times more likely in patients with stage T3 or T4 oral cancer than in patients with lesser grades. CONCLUSIONS: Postoperative complications were not associated with age, sex, or preoperative radiation therapy, but they were associated with recipient site and tumor stage. These results may guide surgeons considering the platysma flap to reconstruct head and neck cancer.

Analysis of neurofibromatosis 1 (NF1) lesions by body segment.

Café-au-lait spots and neurofibromas are defining features of neurofibromatosis 1 (NF1), but they vary greatly in number, size, and clinical importance from patient to patient. The cause of this variability is unknown. We tested the hypotheses that development of these lesions is influenced by local or familial factors. The presence or absence of café-au-lait spots, cutaneous neurofibromas, and diffuse plexiform neurofibromas was recorded for each of 10 divisions of the body surface in 547 NF1 patients, including 117 affected individuals in 52 families. We used stratified Mantel-Haenszel tests to look for local associations between the presence of diffuse plexiform neurofibromas, cutaneous neurofibromas, and café-au-lait spots in individual body segments of NF1 patients. We used a random effects model to obtain intrafamilial correlation coefficients for the age-adjusted number of body divisions affected with each of the three lesions. No significant association was observed between the occurrence of cutaneous and diffuse plexiform neurofibromas, between café-au-lait spots and cutaneous neurofibromas, or between café-au-lait spots and plexiform neurofibromas in the same body segment. The correlation among relatives in the number of body segments affected with café-au-lait spots was 0.45 (95% confidence interval [CI] = 0.18-0.71), with cutaneous neurofibromas, 0.37 (95% CI = 0.15-0.55), and with plexiform neurofibromas, 0.35 (95% CI = 0.15-0.57). We conclude that the development of café-au-lait spots, cutaneous neurofibromas, and plexiform neurofibromas are spatially independent in NF1 patients but that the development of all three lesions is influenced by familial factors.

Patterns of associations of clinical features in neurofibromatosis 1 (NF1).

Neurofibromatosis 1 (NF1) is a common, fully penetrant autosomal dominant disease. The clinical course is generally progressive but highly variable, and the pathogenesis is poorly understood. We studied statistical associations among 13 of the most common or important clinical features in data from four separate sets of NF1 patients: a "developmental sample" of 1,413 probands from the NNFF International Database, an independent "validation sample" of 1,384 probands from the same database, 511 affected relatives of these probands, and 441 patients from a population-based registry in northwest England. We developed logistic regressive models for each of the 13 features using the developmental sample and attempted to validate these models in the other three samples. Age and gender were included as covariates in all models. Models were successfully developed and validated for ten of the 13 features analysed. The results are consistent with grouping nine of the clinical features into three sets: (1) café-au-lait spots, intertriginous freckling and Lisch nodules; (2) cutaneous, subcutaneous and plexiform neurofibromas; (3) macrocephaly, optic glioma and other neoplasms. In addition, three-way interactions among café-au-lait spots, intertriginous freckling and subcutaneous neurofibromas indicate that the first two groups are not independent. Our studies show that some individuals with NF1 are more likely than others to develop certain clinical features of the disease. Some NF1 features appear to share pathogenic mechanisms that are not common to all features.

Unidentified bright objects associated with features of neurofibromatosis 1.

Unidentified bright objects are commonly observed on magnetic resonance imaging in young neurofibromatosis 1 patients, but their clinical and pathologic significance is largely unknown. Diagnostic features of neurofibromatosis 1 include café-au-lait spots, intertriginous freckling, Lisch nodules, neurofibromas, bony lesions, and optic glioma. We investigated the relationship between unidentified bright objects and other features of neurofibromatosis 1. Data from the National Neurofibromatosis Foundation International Database included 523 neurofibromatosis 1 patients between 2 and 20 years of age who had cranial magnetic resonance imaging examinations. The presence or absence of unidentified bright objects, diagnostic features of neurofibromatosis 1, and central nervous system neoplasms was known in these patients. Logistic regressive models were used to measure associations between unidentified bright objects and the other features while controlling for age. The occurrence of unidentified bright objects was associated with the number of diagnostic features, but most significantly with central nervous system neoplasms other than optic gliomas [odds ratio (OR) = 9.0, 95% confidence interval (CI) = 1.2-70], optic gliomas (OR = 2.1, 95% CI = 1.2-3.6), subcutaneous neurofibromas (OR = 2.0, 95% CI = 1.3-3.1), and Lisch nodules (OR = 1.6, 95% CI = 1.1-2.3). These findings suggest a common causal mechanism between unidentified bright objects and these cardinal clinical features in children with neurofibromatosis 1.