Hardware-Efficient 1D CNN for Patient-Specific Early Seizure Detection.

Closed-loop brain-implantable neuromodulation devices are a new treatment option for patients with refractory epilepsy. Seizure detection algorithms implemented on such devices are subject to strict power and area constraints. Deep learning methods, though very powerful, tend to have high computational complexity and thus are typically impractical for resource-constrained neuromodulation devices. In this paper, we propose a compact and hardware-efficient one-dimensional convolutional neural network (1D CNN) structure for patient-specific early seizure detection. Feature extraction techniques and a novel initialization method based on the forward-chaining training and testing scheme are used to improve model performance. Our compact model achieves similar accuracy to that of support vector machines, the state-of-the-art method for seizure detection, while consuming over 20x less power.

Fascicle-Selective Ultrasound-Powered Bidirectional Wireless Peripheral Nerve Interface IC.

This paper presents an innovative, minimally invasive, battery-free, wireless, peripheral nervous system (PNS) neural interface, which seamlessly integrates a millimeter-scale, fascicle-selective integrated circuit (IC) with extraneural recording and stimulating channels. The system also incorporates a wearable interrogator equipped with integrated machine-learning capabilities. This PNS interface is specifically tailored for adaptive neuromodulation therapy, targeting individuals with paralysis, amputation, or chronic medical conditions. By employing a neural pathway classifier and temporal interference stimulation, the proposed interface achieves precise deep fascicle selectivity for recording and stimulation without the need for nerve penetration or compression. Ultrasonic energy harvesters facilitate wireless power harvesting and data reception, enhancing the usability of the system. Key circuit performance metrics encompass a 2.2 µVrms input-referred noise, 14-bit ENOB, and a 173 dB Schreier figure of merit (FOM) for the neural analog-to-digital converter (ADC). Additionally, the ultra-low-power radio-frequency (RF) transmitter boasts a remarkable 1.38 pJ/bit energy efficiency. In vivo experiments conducted on rat sciatic nerves provide compelling evidence of the interface's ability to selectively stimulate and record neural fascicles. The proposed PNS neural interface offers alternative treatment options for diagnosing and treating neurological disorders, as well as restoring or repairing neural functions, improving the quality of life for patients with neurological and sensory deficits.

Flexible 3D printed microwires and 3D microelectrodes for heart-on-a-chip engineering.

We developed a heart-on-a-chip platform that integrates highly flexible, vertical, 3D micropillar electrodes for electrophysiological recording and elastic microwires for the tissue's contractile force assessment. The high aspect ratio microelectrodes were 3D-printed into the device using a conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). A pair of flexible, quantum dots/thermoplastic elastomer nanocomposite microwires were 3D printed to anchor the tissue and enable continuous contractile force assessment. The 3D microelectrodes and flexible microwires enabled unobstructed human iPSC-based cardiac tissue formation and contraction, suspended above the device surface, under both spontaneous beating and upon pacing with a separate set of integrated carbon electrodes. Recording of extracellular field potentials using the PEDOT:PSS micropillars was demonstrated with and without epinephrine as a model drug, non-invasively, along within situmonitoring of tissue contractile properties and calcium transients. Uniquely, the platform provides integrated profiling of electrical and contractile tissue properties, which is critical for proper evaluation of complex, mechanically and electrically active tissues, such as the heart muscle under both physiological and pathological conditions.

Machine Learning with Imbalanced EEG Datasets using Outlier-based Sampling.

Epilepsy is a neurological disorder which causes seizures in over 65 million people worldwide. Recently developed implantable therapeutic devices aim to prevent symptoms by applying acute electrical stimulation to the seizure-generating brain region in response to activity detected by on-device machine learning hardware. Many training algorithms require an equal number of examples for each target class (e.g. normal activity and seizures), and performance can suffer if this condition is not satisfied. In the case of epilepsy, poor performance can cause seizures to be missed, or stimulation to be applied erroneously. As there is an abundance of normal (interictal) data in clinical EEG recordings, but seizures are rare events (less than 1% of the dataset), the data available for training is severely imbalanced. There are several conventional pre-processing methods used to address imbalanced class learning, such as down-sampling of the majority class and up-sampling of the minority class, but each have performance drawbacks. This paper presents an improved method which involves reducing the majority class down to the most effective interictal outlier samples. Outliers are determined by using Exponentially Decaying Memory Signal Energy (EDMSE) features with Isolation Forests and an ANOVA-based method, which involves comparing a moving feature window to a baseline reference window. Outlier-based sampling is tested with two classifiers (KNN and Logistic Regression) and achieves higher accuracy (∼2% increase) and fewer false positives (∼38% decrease), along with a lower latency (∼3 seconds shorter) compared to conventional training set pre-processing methods.

Utility of CT and MRI in assessment of mandibular involvement in oral cavity cancer.

OBJECTIVE: Oral cavity squamous cell carcinoma (SCC) may present with early invasion of mandibular bone. Preoperative planning of surgery is essential considering patient's postoperative quality of life. Our purpose was to evaluate the efficacy of computer tomography scan (CT) and magnetic resonance imaging (MRI) in detecting mandibular bone involvement in oral SCC. METHODS: A retrospective study was conducted on 98 patients with SCC of floor of mouth, lower alveolus and retromolar trigone operated on with curative intent. Preoperative CT and MRI scans were re-reviewed by a consultant radiologist and original histology slides were re-reviewed by 3 pathologists. RESULTS: Forty-five patients were included in the final study. Combined CT and MRI had a sensitivity of 100% and a specificity of 72%. CONCLUSION: The results suggest that combined CT and MRI have diagnostic utility in detecting mandibular invasion by oral cancer, but with a significant false positive rate.

Presentation of Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma in a Warthin Tumor: Case Report and Literature Review.

Warthin tumor is the second most common salivary gland neoplasm. It occurs more commonly in males than in females. Malignant transformation in Warthin tumor is a rare but well-recognized phenomenon; however, the development or presentation of lymphoma in a Warthin tumor is rare. An 80-year-old man presented with painless mass of the right parotid gland of 2 years duration with recent ulceration of the overlying skin and right cervical lymphadenopathy underwent a surgical resection of parotid mass and biopsy of the periglandular lymph nodes. The histological diagnosis was malignant lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, present within the stroma of a Warthin tumor, and also present within the adjacent lymph node. This case is the third reported case describing a collision of Warthin tumor and chronic lymphocytic leukemia/small lymphocytic lymphoma. It also emphasizes the importance of careful examination of the lymphoid stroma of these tumors.

Low-latency VLSI architecture for neural cross-frequency coupling analysis.

Growing evidence suggests that cross-frequency coupling (CFC) is a key mechanism in neuronal computation, communication, and learning in the brain. Abnormal CFC has been implicated in pathological brain states such as epilepsy and Parkinson's disease. A reduction in excessive coupling has been shown in effective neuromodulation treatments, suggesting that CFC may be a useful feedback measure in closed-loop neural stimulation devices. However, processing latency limits the responsiveness of such systems. A VLSI architecture is presented which implements three selectable measures of CFC to enable the application specific trade-off between low-latency and high-accuracy processing. The architecture is demonstrated using in-vitro human neocortical slice recordings, with a latency of 48ms.

Impact of positive margins on outcomes of oropharyngeal squamous cell carcinoma according to p16 status.

BACKGROUND: Currently, positive surgical margins in head and neck cancer are considered to be an indicator for postoperative chemoradiotherapy (CRT) over radiotherapy (RT) alone. However, there are less data regarding the impact of margin status on human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (SCC). METHODS: We performed a retrospective review of 55 patients with oropharyngeal SCC undergoing primary surgical treatment. The impact of margin status on disease-specific survival (DSS) was studied according to p16 status. RESULTS: Twenty-one patients had positive margins. Adjuvant treatment in these cases was CRT (n = 6), RT alone (n = 14), and none (n = 1). Among p16-negative patients, positive margins and dysplasia at margins predicted significantly worse DSS. Among patients with p16-positive disease, margin status had no impact on DSS. CONCLUSION: Patients with p16-positive oropharyngeal SCC and positive margins after excision maintain a low risk of recurrence despite most receiving RT alone as adjuvant treatment. These findings raise questions regarding the additional benefit of postoperative CRT in this group.

Impact of mandibular invasion on prognosis in oral squamous cell carcinoma four centimeters or less in size.

OBJECTIVES/HYPOTHESIS: Previous studies have reported variable results for the impact of bone invasion on survival in oral cancer. It is unclear whether bone invasion in small (≤4 cm) squamous cell carcinomas (SCC) of the oral cavity is an independent adverse prognosticator. Our objective was to investigate impact on survival of bone invasion in SCC of floor of mouth (FOM), lower alveolus (LA), and retromolar trigone (RMT) ≤4 cm in size. STUDY DESIGN: Retrospective study of 96 patients with SCC of the FOM, LA, and RMT undergoing primary surgical treatment. METHODS: Original pathology reports and slides were reviewed by three pathologists. Level of bone invasion was categorized as cortical or medullary. Main outcome measures were local control (LC) and overall survival (OS). RESULTS: Bone invasion was present in 31 cases (32%). On review of pathology slides, all cases of bone invasion demonstrated medullary involvement. Median follow-up was 36 months for all patients, and 53 months for patients not dying from cancer. Among tumors ≤4 cm, bone invasion was associated with significantly worse LC (P =.04) and OS (P =.0005). Medullary invasion (hazard ratio: 2.2, 95% confidence interval: 1.1-4.4, P =.03), postoperative radiotherapy (hazard ratio: 0.3, 95% confidence interval: 0.1-0.5, P <.001), and positive pathologic nodal status (hazard ratio: 4.1, 95% confidence interval: 1.9-8.6, P <.001) were independent predictors of worse OS among the entire cohort. CONCLUSIONS: Mandibular medullary bone invasion is a poor prognosticator in oral cancers, irrespective of small size of primary tumor. Such cases should be considered for postoperative radiotherapy. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:849-854, 2017.

Incidence of intraglandular lymph nodes within submandibular gland, and involvement by floor of mouth cancer.

Resection of the submandibular gland is generally undertaken as an integral component of level I neck dissection for oral cancer. However, it is unclear whether lymph nodes are present within the submandibular gland which may form the basis of lymphatic spread. Our purpose was to investigate the frequency of lymph nodes within the submandibular gland, and the incidence and mechanism of submandibular gland involvement in floor of mouth cancer. Retrospective review of 177 patients with oral cancer undergoing neck dissection. Original pathology slides of floor of mouth cases were re-reviewed by two pathologists to determine frequency of intraglandular lymph nodes, and incidence and mechanism of submandibular gland involvement by cancer. The overall incidence of cervical metastases was 36.4 %, of whom 44 % had level I metastases. Level I metastases were significantly more common in floor of mouth than tongue cancers (p = 0.004). Among 50 patients with floor of mouth cancer undergoing re-review of pathology slides, intraglandular lymph nodes were not found in any of 69 submandibular glands. Submandibular gland involvement by cancer was present in two patients, representing 1 % of all oral cancers, and 4 % FOM cases. Mechanisms of involvement were direct extension, and by an apparent novel mechanism of carcinoma growing along bilateral Wharton's ducts. Despite the high incidence of level I metastasis in floor of mouth, lymphatic metastases to submandibular gland are unlikely based on absence of intraglandular lymph nodes. We describe a previously unreported mechanism of submandibular gland involvement.

Impact of lymphocytic thyroiditis on incidence of pathological incidental thyroid carcinoma.

BACKGROUND: The purpose of this study was to investigate the impact of lymphocytic thyroiditis on incidence of incidental thyroid cancers. METHODS: We conducted a retrospective review of 713 consecutive patients who underwent thyroidectomies. Incidental thyroid cancer was defined as an unexpected cancer discovered on pathological examination outside the index nodule undergoing preoperative cytology. RESULTS: We excluded 65 cases because of preoperative diagnosis of thyroid cancer, and 68 because of nonincidental cancer within the index nodule. Among the remaining 580 cases, there were 43 cases (7.4%) of incidental thyroid cancers. Incidental thyroid cancers were significantly associated with moderate/severe lymphocytic thyroiditis (relative risk = 2.5; p = .03). Sixteen of 56 patients with moderate/severe lymphocytic thyroiditis had Graves' disease, none of whom had incidental thyroid cancer. The risk of incidental thyroid cancer associated with moderate/severe lymphocytic thyroiditis was significantly higher in non-Graves' than patients with Graves' disease (p = .05). CONCLUSION: The risk of incidental thyroid cancer is significantly increased in patients with moderate/severe lymphocytic thyroiditis. Moderate/severe lymphocytic thyroiditis associated with Graves' disease seems to have a lower risk of incidental thyroid cancer. © 2016 Wiley Periodicals, Inc. Head Neck 39: 122-127, 2017.

Pattern of invasion and lymphovascular invasion in squamous cell carcinoma of the floor of the mouth: an interobserver variability study.

AIMS: Lymphovascular invasion (LVI) and the histological pattern of invasion (POI) at the invasive tumour front have been reported as adverse prognosticators in oral squamous cell carcinoma (SCC). However, assessment of these parameters is hampered by variation in the criteria used for their evaluation. Our objective was to evaluate interobserver variability in the assessment of the POI and LVI in SCC of the floor of the mouth (FOM), and to study the impact of the POI on clinical outcomes by using varying quantitative cut-offs. METHODS AND RESULTS: Fifty-eight cases of FOM SCC were independently evaluated for the POI and LVI by three pathologists. Interobserver variability was analysed by the use of Fleiss kappa statistics. Interobserver agreement was substantial for the assessment of LVI [κ = 0.64, 95% confidence interval (CI) 0.60-0.68]. Interobserver agreement was moderate for evaluation of the POI with a 50% cut-off (κ = 0.58, 95% CI 0.54-0.62), a 20% cut-off (κ = 0.58, 95% CI 0.54-0.62) cut-off, and worst POI (κ =0 .43, 95% CI 0.39-0.46). A consensus diagnosis of the POI was a significant predictor of locoregional recurrence (LRR), disease-specific survival (DSS) and overall survival (OS) on univariate analysis when a 50% cut-off was used (LRR, P = 0.01; DSS, P = 0.01; OS, P = 0.01) and when a 20% cut-off was used (LRR, P = 0.02; DSS, P = 0.02; OS, P = 0.03), but was not significant when worst POI was used (LRR, P = 0.18; DSS, P = 0.16; OS, P = 0.17). CONCLUSIONS: Interobserver agreement in the diagnosis of LVI was substantial. The POI at the 50% and 20% cut-offs is moderately reproducible, and has prognostic value in FOM SCC. Further studies are necessary to establish the optimum quantitative cut-off for the POI.

Association of Extracapsular Spread With Survival According to Human Papillomavirus Status in Oropharynx Squamous Cell Carcinoma and Carcinoma of Unknown Primary Site.

IMPORTANCE: The presence of extracapsular spread (ECS) of metastatic nodes is considered a poor prognosticator in head and neck cancer, with postoperative chemoradiation therapy often recommended over radiation therapy alone in such cases. However, there is less clarity regarding the effect of ECS on human papillomavirus-associated oropharynx squamous cell carcinoma (OPSCC) or carcinoma of unknown primary site (CUP). OBJECTIVE: To investigate the association of ECS according to human papillomavirus status in OPSCC and CUP with survival. DESIGN, SETTING, AND PARTICIPANTS: This investigation was a retrospective cohort study performed between August 1998 and March 2015 at an academic teaching hospital. Participants were 83 patients with OPSCC (n = 62) or CUP (n = 21) undergoing neck dissection as part of initial treatment. MAIN OUTCOME AND MEASURES: Human papillomavirus status was determined by p16 immunohistochemistry. The presence of ECS was extrapolated from pathology reports, and the extent of ECS was determined by rereview of original pathology slides. Disease-specific survival (DSS) and recurrence-free survival (RFS) were assessed. RESULTS: Among 83 patients (71 male), there were 45 p16-positive and 38 p16-negative tumors. Fifty-one patients had ECS, which was graded as extensive in 43 cases. The median follow-up was 31 months for all patients and 50 months for surviving patients. Among the entire cohort, adverse predictors of RFS were p16-negative status (hazard ratio [HR], 9.4; 95% CI, 3.3-27.2) and ECS (HR, 6.5; 95% CI, 2.0-21.6). Adverse predictors of DSS were p16-negative status (HR, 16.8; 95% CI, 3.9-71.2) and ECS (HR, 8.3; 95% CI, 2.0-35.3). Among p16-negative patients, ECS was significantly associated with worse RFS (HR, 9.7; 95% CI, 1.3-72.3) and DSS (HR, 8.7; 95% CI, 1.1-62.7). In contrast, among p16-positive patients, ECS had no effect on RFS (HR, 1.1; 95% CI, 0.2-7.8) or DSS (HR, 1.2; 95% CI, 0.1-18.7). CONCLUSIONS AND RELEVANCE: The presence of ECS appears to be associated with survival in OPSCC and CUP according to p16 status. Our findings raise questions regarding the benefits of postoperative chemoradiation therapy in p16-positive patients with ECS.

Importance of lymphovascular invasion and invasive front on survival in floor of mouth cancer.

BACKGROUND: The floor of mouth (FOM) is a common site of oral squamous cell carcinoma (SCC). The purpose of this study was to investigate pathological predictors of survival in FOM SCC. METHODS: We conducted a retrospective study of 54 consecutive patients undergoing surgery for FOM SCC. Pathological parameters were extracted from histological reports with original pathology slides re-reviewed by 2 pathologists for missing data. RESULTS: On univariate analysis, depth of invasion >10 mm (p = .009), lymphovascular invasion (LVI; p < .001), noncohesive invasive front (p = .006), perineural invasion (PNI; p = .003), and nodal metastases (p = .02) were significant predictors of overall survival. On multivariate analysis, LVI (p = .009) and invasive front (p < .001) remained significant. Postoperative radiotherapy improved survival in patients with LVI, PNI, and nodal metastases, and was just outside significance for noncohesive invasive front (p = .06). CONCLUSION: LVI is an adverse prognosticator in FOM SCC and indicates postoperative radiotherapy. Further study is required to investigate the importance of invasive front. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1528-E1534, 2016.

Effect of Endotracheal Tube Size on Vocal Outcomes After Thyroidectomy: A Randomized Clinical Trial.

IMPORTANCE: The optimum size of endotracheal tube (ETT) for general anesthesia remains unresolved. Choice of ETT size may be of particular relevance to thyroid surgery because of the increased risk of laryngeal trauma and concerns regarding postoperative vocal outcomes. OBJECTIVE: To test our hypothesis that intubation with a smaller ETT would lead to reduced postoperative vocal impairment and associated reduced laryngoscopic evidence of laryngeal trauma compared with intubation with a standard-size ETT. DESIGN, SETTING, AND PARTICIPANTS: This double-blind randomized clinical trial studied patients 18 years and older undergoing elective thyroidectomy at an academic teaching hospital from October 15, 2012, through June 13, 2013. INTERVENTIONS: Patients were randomized to group 1 (standard-size ETT, 8.0 mm for men and 7.5 mm for women; n = 24) or group 2 (small ETT, 7.0 mm for men and 6.5 mm for women; n = 25). Patients were assessed preoperatively and at 24 hours and 3 weeks postoperatively. MAIN OUTCOMES AND MEASURES: Fiberoptic videolaryngoscopy with modified scoring system, voice assessment using the GRBAS (grade, roughness, breathiness, asthenia, strain) rating scale, vocal self-assessment using the 30-item Voice Handicap Index, and subjective pain score. RESULTS: At 24 hours, no significant differences were found between patients in groups 1 and 2 in change in GRBAS scores, change in laryngoscopic score (1.71 vs 1.76, P = .90), or postoperative pain score (3.3 vs 3.2, P = .91). At 3 weeks, no significant differences were found in changes in the 30-item Voice Handicap Index score (-2.2 vs -1.3, P = .74), GRBAS scores, or laryngoscopic score (0.25 vs 0.16, P = .67). CONCLUSIONS AND RELEVANCE: We did not find evidence that smaller ETT size for thyroidectomy has any significant effect on postoperative vocal outcomes, incidence of laryngeal trauma as assessed by laryngoscopy, or pain scores. However, because of the small sample size, our study may have been underpowered to detect small differences. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02136459.

Impact of current smoking and alcohol consumption on gastrostomy duration in patients with head and neck cancer undergoing definitive chemoradiotherapy.

IMPORTANCE: Prophylactic gastrostomy tube (GT) insertion prior to chemoradiotherapy is a valuable nutritional adjunct in patients with head and neck cancer undergoing nonsurgical treatment. However, concerns have been expressed regarding high rates of GT dependence. There is little information in the literature regarding the impact of modifiable risk factors such as smoking and alcohol consumption on duration of GT use and dependence rates. OBJECTIVE: To study the duration of GT use in patients with head and neck cancer at our institution and to investigate risk factors for prolonged GT duration and dependence, including the impact of smoking and alcohol consumption. DESIGN, SETTING, AND PARTICIPANTS: This retrospective study at an academic teaching hospital included 104 patients with squamous cell carcinoma of the head and neck undergoing definitive treatment with either chemoradiotherapy (n = 84) or radiotherapy alone (n = 20). INTERVENTIONS: Prophylactic GT insertion prior to commencement of treatment. MAIN OUTCOMES AND MEASURES: Duration of GT use after completion of chemoradiotherapy or radiotherapy and the impact of risk factors on same. Duration of GT use was analyzed using Kaplan-Meier survival curves, with censoring of patients who developed cancer recurrence or died. RESULTS: The median duration of GT use was 9 months. The actuarial GT persistence rate at 1 year was 35%. Current smoking (hazard ratio [HR], 0.47; 95% CI, 0.27-0.81; P = .01) and current heavy alcohol consumption (HR, 0.55; 95% CI, 0.32-0.97; P = .04) were significant predictors of GT persistence. On multivariate analysis, only current smoking remained significant (HR, 0.53; 95% CI, 0.30-0.94; P = .03). Age 65 years or older, advanced T classification, larynx and/or hypopharynx primary site, and posttreatment neck dissection were not significant risk factors. CONCLUSIONS AND RELEVANCE: Current smoking and current heavy alcohol consumption are predictive of prolonged GT requirement in patients with head and neck cancer undergoing prophylactic GT insertion before definitive radiotherapy or chemoradiotherapy. Further study is required to investigate whether smoking or drinking cessation can reduce GT dependence rates in this population.

Oncologic outcomes of total laryngectomy: impact of margins and preoperative tracheostomy.

BACKGROUND: The purpose of this present study was to investigate risk factors for local recurrence and death after total laryngectomy, with particular emphasis on pattern of local recurrence (stomal vs pharyngeal/base of tongue) and impact of preceding tracheostomy. METHODS: We conducted a retrospective review of 75 consecutive total laryngectomies for cancer of the larynx. RESULTS: Nineteen patients underwent preoperative tracheostomy, which was a significant risk factor for local recurrence (p = .04). With regard to pattern of local recurrence, preoperative tracheostomy (p = .03) and pathological nodal status (pN+; p = .04) were significant for stomal, but not pharyngeal recurrence; whereas positive margins (p = .01) was significant for pharyngeal, but not stomal recurrence. Preoperative tracheostomy, pN+, lymphovascular invasion, and positive margins were all significant for survival. CONCLUSION: Preoperative tracheostomy continues to be a significant adverse prognosticator in patients undergoing total laryngectomy. Our findings also suggest distinct causative factors for different patterns of postlaryngectomy local recurrence.

Pharyngocutaneous fistula after salvage laryngectomy: impact of interval between radiotherapy and surgery, and performance of bilateral neck dissection.

BACKGROUND: Pharyngocutaneous fistula is a serious complication of total laryngectomy. The purpose of this study was to examine predisposing factors at our institution. METHODS: We conducted a retrospective review of 94 consecutive patients undergoing total laryngectomy. Cases with hypopharyngeal primary tumors or undergoing extended hypopharyngeal resection with flap augmentation of the pharynx were excluded. RESULTS: Seventy-four cases met inclusion criteria. A total of 25.7% patients developed a pharyngocutaneous fistula. The fistula rate was higher after salvage laryngectomy than after primary surgery (34.0% vs 11.1%; p = .05). Among salvage laryngectomies, performance of laryngectomy within 1 year of completion of radiotherapy (p = .006) and performance of concomitant bilateral neck dissection (p = .02) were significant risk factors for development of a fistula. Radiation dose, addition of chemotherapy, use of pectoralis major myofascial flap, preoperative tracheostomy, primary puncture, primary tumor subsite, and initial T classification were not significant. CONCLUSION: Interval between completion of radiotherapy and surgery is significantly associated with pharyngocutaneous fistula after salvage total laryngectomy.

Hypocalcemia after total laryngectomy: incidence and risk factors.

OBJECTIVES/HYPOTHESIS: Hypocalcemia is common in the initial period after total laryngectomy. The purpose of the present study was to study the incidence of and risk factors for postlaryngectomy hypocalcemia at our institution. STUDY DESIGN: Retrospective review of 65 consecutive total laryngectomies. METHODS: Clinical data and calcium levels for the first postoperative week were collected. Biochemical hypocalcemia was defined as any corrected calcium level of < 2.0 mmol/l in the first postoperative week. Severe hypocalcemia was defined as a calcium of < 1.8 mmol/l, or symptoms of hypocalcemia. Risk factors for hypocalcemia were studied. RESULTS: Five cases were excluded due to concomitant abdominal surgery (3), preoperative hypocalcemia (1), and no postoperative calcium levels (1). A total of 43% of patients had postoperative biochemical hypocalcemia. On univariate analysis, bilateral neck dissection was significant for hypocalcemia (P = 0.02), with pT4 classification having borderline significance (P = 0.07). On multivariate analysis, bilateral neck dissection (P = 0.02) and salvage surgery were significant (P = 0.03), with pT4 stage again having borderline significance (P = 0.05). Extent of thyroidectomy, extent of pharyngectomy, and preoperative tracheostomy were not significant. Fifteen patients (25%) had severe hypocalcemia. There were no significant risk factors for severe hypocalcemia identified. CONCLUSIONS: Hypocalcemia is common after total laryngectomy, particularly in the postradiotherapy setting and in patients undergoing bilateral neck dissection. Preservation of one thyroid lobe does not appear to significantly reduce the risk.

Elective neck dissection for no neck during salvage total laryngectomy: findings, complications, and oncological outcome.

IMPORTANCE: Optimum management of the clinically negative neck in the presence of primary site recurrence of laryngeal or hypopharyngeal cancer remains unclear. OBJECTIVE: To examine the incidence of occult cervical nodal metastatic disease in patients undergoing salvage laryngectomy with necks clinically staged as N0 at the time of recurrence and to define the role of elective neck dissection in this population with regard to risk of complications and oncologic outcomes. DESIGN: Retrospective study of patients treated from 1996 through 2011. SETTING: Academic teaching hospital. PARTICIPANTS: All patients undergoing salvage total laryngectomy for squamous cell carcinoma of larynx or hypopharynx after failed initial radiotherapy or chemoradiotherapy with radiographically N0 neck at time of recurrence. MAIN OUTCOMES AND MEASURES: Primary outcome measure was incidence of cervical nodal metastases detected by means of pathological examination of elective neck dissection specimens. Secondary outcome measures were incidence of major postoperative complications and regional cancer control. RESULTS: Forty-five patients were included. Thirty-eight underwent elective unilateral (20) or bilateral (18) ND at the time of laryngectomy. Three patients (8%) had occult metastases (3 of 56 dissected heminecks [5%]). The incidence of major wound complications was significantly greater in patients undergoing bilateral ND (12 of 18 [67%]) than in patients undergoing unilateral or no ND (8 of 27 [30%]) (P = .03). There was no significant difference in regional control according to whether bilateral, unilateral, or no ND was performed. CONCLUSIONS AND RELEVANCE: The incidence of occult metastatic disease in N0 necks in patients undergoing salvage surgery after radiotherapy is low. Neck dissection in this population does not seem to have a significant impact on regional cancer control. The need for elective ND, particularly bilateral ND, should be balanced against possible increased risk of morbidity in this group.