Cadaveric and Computed Tomography Analysis of the Anterior Ethmoidal Artery Flap.

BACKGROUND: The anterior ethmoidal artery (AEA) flap has been successful in repairing anterior nasal septal perforations and has been presumed to be axially based on AEA branches coursing through or around the cribriform plate (CP). However, limited evidence supports the flap's axial supply. The purposes of this cadaveric and computed tomography (CT) study were to assess the arterial anatomy from the CP to the septum, and to determine AEA flap length to predict ideal flap base width. METHODS: Ten fresh latex-injected cadavers were utilized for endoscopic dissection to identify arteries traversing the CPs on each side. First, arterial trajectories along the dorsal septum were recorded. Measurements were then made bilaterally along the septum from the middle turbinate (MT) axilla to the nasal branch of the AEA (NBAEA) traversing the CP. Additionally, 100 sinus CTs were reviewed to measure AEA flap lengths bilaterally. RESULTS: From 10 cadavers, 20 sides were utilized for measurements. In all cadavers, the AEA septal branches coursed diagonally or horizontally along the dorsal septum, and never directly vertically. The mean distance from the MT axilla to the NBAEA was 1.24 ± 1.93 cm (range = 1-1.5 cm). Based on CTs, the mean AEA flap length was 6.40 ± 0.60 cm. CONCLUSIONS: Based on the non-vertical courses of AEA septal branches, the AEA flap is more likely a random transposition flap than an axial flap. Average AEA flap length ranged from 6.0 to 7.0 cm. Assuming 3:1 length:width ratios, AEA flap base widths should be about 2.0-2.3 cm. LEVEL OF EVIDENCE: NA Laryngoscope, 134:2100-2104, 2024.

Cognitive Function and Postoperative Outcomes in Patients with Head and Neck Cancer.

OBJECTIVE: Determine the relationship between cognitive function and postoperative outcomes. METHODS: This IRB-approved retrospective cohort study included all patients treated between August 2015 and March 2020 undergoing major surgery for aerodigestive cancer or cutaneous/thyroid cancer that required free-flap reconstruction at Henry Ford Hospital. Routine administration of the Montreal Cognitive Assessment (MoCA) was completed as part of preoperative psychosocial evaluation. Outcomes included postoperative diagnosis of delirium, discharge disposition, return to the emergency department within 30 days of surgery, and readmission within 30 days of surgery. Univariate and multivariate logistic regression were used to determine the associations between preoperative MoCA score and each outcome measure. RESULTS: One hundred thirty-five patients with HNC were included in the study (mean [SD] age, 60.7 [±10.8] years; 70.4% [n = 95] male; 83.0% [n = 112] White, 16.3% [n = 22] Black). The average preoperative MoCA score was 23.4 (SD ± 4.5). Based on the MoCA score, 35% (n = 47) scored ≥26 (i.e., normal cognitive status), 55.6% (n = 75) scored between 18 and 25 (i.e., mild impairment), 8.1% (n = 11) scored between 10 and 17 (i.e., moderate impairment), and 1.5% (n = 2) scored <10 (i.e., severe impairment). After adjusting for other variables, a lower MoCA score was associated with discharge disposition to a location other than home and prolonged length of hospital stay. CONCLUSIONS: Preoperative cognitive function in patients undergoing major head and neck surgery for head and neck cancer was associated with discharge destination and length of stay. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:2999-3005, 2023.

Randomized Phase 3, Double-Blind, Placebo-Controlled Study of Prophylactic Gabapentin for the Reduction of Oral Mucositis Pain During the Treatment of Oropharyngeal Squamous Cell Carcinoma.

PURPOSE: The purpose of this paper is to determine whether prophylactic gabapentin usage in patients undergoing definitive concurrent chemotherapy and radiation therapy (chemoRT) for oropharyngeal cancer (OPC) improves treatment-related oral mucositis pain, opioid use, and feeding tube (FT) placement. METHODS AND MATERIALS: This double-blind, randomized phase 3 study for patients with locally advanced OPC undergoing chemoRT randomly allocated patients to prophylactic gabapentin (600 mg thrice daily) or placebo. The primary endpoint was change in Patient-Reported Oral Mucositis Symptom (PROMS) scores over the entire treatment period (baseline to 6 weeks post-radiation therapy [RT] follow-up) with higher scores indicating worse outcomes. Opioid requirements, FT placement, and other patient-reported quality of life (QOL) metrics (Functional Assessment of Cancer Therapy-Head and Neck [FACT-HN] and Patient-Reported Outcomes version of the National Cancer Institute Common Terminology Criteria for Adverse Events [PRO-CTCAE]) were assessed. Lower scores suggested poorer QOL with the FACT-HN questionnaire, and higher scores suggested worse outcomes with the PRO-CTCAE questionnaire. Questionnaires were administered at baseline, weekly during RT, and at 6 weeks post-RT follow-up. Repeated measures analysis of variance was used to detect differences in PROMS scores and change in opioid use from baseline. Wilcoxon rank sum tests were used to compare averages for the other secondary endpoints. A P value less than .05 was considered statistically significant. RESULTS: Treatment arms were well balanced overall, including T and N staging and dosimetric variables. There were 58 patients analyzed. No significant difference was found in PROMS scores (mean 29.1, standard deviation [SD] 22.5 vs 20.1, SD 16.8 for gabapentin vs placebo, respectively, P = .11). The FACT-HN functional well-being index had a significant decrease in scores from baseline to follow-up in the gabapentin arm (median -6, interquartile range [IQR] -10.0 to -0.5 vs -1, IQR -5.5 to 3.0, P = .03). PRO-CTCAE scores increased significantly at follow-up for gabapentin (median 6.5, IQR 3.5-11.8 vs 1, IQR -2.0 to 6.0, P = .01). There was no significant difference in average or change in opioid use. FT placement was significantly higher in the gabapentin arm (62.1% vs 20.7%, P < .01). CONCLUSIONS: This study suggests that prophylactic gabapentin is not effective in improving treatment-related oral mucositis symptoms in a select population of patients with OPC undergoing definitive chemoRT.

Recurrent malignant peripheral nerve sheath tumor of the parietal scalp.

Malignant peripheral nerve sheath tumors (MPNSTs) are a rare and aggressive subtype of sarcomas defined by their neural origin. Head and neck manifestations are particularly uncommon. Challenges exist in diagnosis, management, and recurrence. Achieving local control, particularly in the head and neck region, is difficult. We present a patient with a rapidly enlarging MPNST on the right parietal calvarium shortly after resection of a right vagus nerve MPNST. Recommendation was made for excision and reconstruction with a local advancement flap followed by radiation therapy. Local control with good aesthetic outcome was achieved by applying recommended surgical and oncologic principles.

Comparison of psychosocial factors over time among HPV+ oropharyngeal cancer and tobacco-related oral cavity cancer patients.

INTRODUCTION: The role of human papilloma virus (HPV) in the pathogenesis of oropharyngeal squamous cell carcinoma (OPSCC) is well documented, as is the excellent prognosis of patients with HPV-associated disease; in contrast, oral cavity squamous cell carcinoma (OCSCC) is associated with tobacco and alcohol use and has a worse prognosis. While causative factors, staging, and treatment guidelines differ between these cancer subsets, few studies have compared psychosocial factors in these groups. OBJECTIVE: To explore differences in psychosocial factors between HPV+ OPSCC patients versus OCSCC smokers. METHODS: A prospective cohort study at a single multidisciplinary, tertiary care HNC center was completed with recruitment from 2010 to 2013 using self-administered questionnaires before treatment and at 12 months. Patients were included with a diagnosis of HPV+ OPSCC or OCSCC with a smoking history. 38 (21 HPV+ OPSCC/17 OCSCC) met criteria. The main outcomes included self-efficacy, symptom severity, cancer worry, and depression. RESULTS: A total of 38 (21 HPV+ OPSCC/17 OCSCC) patients (mean age: 57 [32-76], 73.7% male, 78.9% Caucasian, 71% stage IV) met inclusion criteria. OPSCC patients tended to be of male sex, Caucasian race, and single. Furthermore, OPSCC patients were more likely than OCSCC patients to have private insurance, be employed, and use alcohol and tobacco less frequently. Regarding psychosocial factors, HPV+ OPSCC patients reported lower symptom severity (2.7 versus 3.3), depression (12.0 versus 14.0) and cancer worry (2.8 versus 3.2) at baseline compared to OCSCC patients. Depression decreased significantly over time in OPSCC patients (12.0 to 9.9; effect size: -3.2 (95% CI: -5.9 to -0.4)). Although not statistically significant, cancer worry decreased in both groups (2.8 to 2.4 and 3.2 to 2.7, respectively, effect sizes: -0.3 (95% CI: -0.7-0.08) and -0.6 (95% CI: -1.2-0.05), respectively). No statistically significant differences in patterns of change over time were noted between groups. CONCLUSIONS AND RELEVANCE: This pilot study highlighted a pattern of reduced quality of life parameters in OCSCC patients at baseline with similar improvements over time compared to the OPSCC cohort. Although different in cancer etiology and treatment plans, HPV+ OPSCC and tobacco-related OCSCC patients both require multidisciplinary cancer care plans that address psychosocial concerns. LEVEL OF EVIDENCE: 2B.

Factors associated with gastrostomy tube dependence following salvage total laryngectomy with microvascular free tissue transfer.

BACKGROUND: Following salvage total laryngectomy (STL) with microvascular-free tissue transfer (MFTT), patients are at high risk for swallowing dysfunction, but risk factors for persistent gastrostomy tube (G-tube) dependence are unknown. METHODS: Retrospective review of 33 patients who underwent STL with MFTT. RESULTS: A total oral diet was achieved by 81% of patients with ≥6 months of postoperative follow-up. Approximately 27% of patients were G-tube dependent preoperatively with 67% achieving a total oral diet postoperatively. Factors associated with persistent G-tube dependence included pT4 tumor, pN2+ status, more extensive pharyngectomy, and re-irradiation. Strictures occurred in 30% of patients and were associated with more extensive pharyngectomy and tubed reconstruction. CONCLUSIONS: For patients undergoing STL with MFTT, the majority of patients achieve a total oral diet regardless of their preoperative swallowing function. Advanced-stage recurrent tumors and increased extent of pharyngectomy contribute to poorer swallowing outcomes.

Swallowing Outcomes in Elderly Patients following Microvascular Reconstruction of the Head and Neck.

Objective To describe swallowing outcomes in elderly patients undergoing microvascular reconstruction of the upper aerodigestive tract and identify risk factors for poor postoperative swallowing function. Study Design Case series with chart review. Setting Academic medical center. Subjects and Methods Sixty-six patients aged ≥70 years underwent microvascular reconstruction of the upper aerodigestive tract. The primary outcome measure was the Functional Oral Intake Scale (FOIS); preoperative and postoperative scores were dichotomized to define "good swallowing" and "poor swallowing." Logistic regression was performed to identify risk factors for poor postoperative swallowing function. Results In total, 91% of reconstructions were performed for oncologic defects. The most common defect site was the oral cavity (67%), and the anterolateral thigh (29%) was the most frequently used donor site. At 3-year follow up, 75% of patients had good swallowing function with 95% of patients who achieved good swallowing function doing so within 6 months of surgery. On multivariable analysis, patients with pT4 tumors (odds ratio [OR], 5.2; 95% confidence interval [CI], 1.0-25.6) and those undergoing at least partial glossectomy (OR, 4.7; 95% CI, 1.1-20.7) were more likely to experience poor swallowing function at 6-month follow-up. Conclusion Approximately half of elderly patients achieve good swallowing function within 6 months following microvascular reconstruction of the upper aerodigestive tract. Elderly patients with pT4 tumors and those requiring glossectomy are at highest risk for poor swallowing outcomes. These data can be used to inform preoperative patient counseling and design interventions aimed at improving swallowing function in those at high risk for poor outcomes.

Thirty-day readmission in patients undergoing head and neck microvascular reconstruction.

BACKGROUND: Characteristics of 30-day unplanned readmissions after head and neck microvascular reconstruction remain poorly understood. METHODS: We conducted a retrospective cohort of patients who underwent head and neck microvascular reconstruction between 2010 and 2015. RESULTS: The 30-day unplanned readmission rate was 13.0% (64/493). The most common readmission diagnoses were dehiscence, surgical site infection, or fistula (45.3%; n = 29). Of the readmissions, 46.9% (30/64) occurred within 7 days of discharge from the hospital. Risk factors for readmission on multivariable analysis included body mass index (BMI) < 21 kg/m (odds ratio [OR] 2.47; 95% confidence interval [CI] 1.36-4.47), primary site of oropharynx (OR 1.66; 95% CI 1.17-6.06), hypopharynx/larynx (OR 3.66; 95% CI 1.70-7.88), or sinonasal/skull base (OR 4.07; 95% CI 1.43-11.55), and fistula during the index hospitalization (OR 2.98; 95% CI 1.22-7.24). CONCLUSION: More than 1 in 10 patients undergoing head and neck microvascular reconstruction has a 30-day unplanned readmission, most commonly related to wound complications. Further efforts are needed to determine optimal 30-day unplanned readmission reduction strategies.

PROGNOSTIC VARIABLES AFFECTING PRIMARY TREATMENT OUTCOME FOR MEDULLARY THYROID CANCER.

OBJECTIVE: Identifying prognostic risk factors and determining the efficacy of common surgical treatments is critical to determine optimal treatment strategies for patients with medullary thyroid carcinoma (MTC). The objective of this study was to review a contemporary institutional experience with MTC primary treatment with 2 goals: to identify prognostic factors that impact survival and to study the effect of neck dissection on those outcomes. METHODS: This study was a retrospective case series of patients with MTC who underwent at least a total thyroidectomy with curative intent. Clinical parameters including tumor and nodal staging with corresponding pathology findings were identified. Survival endpoints included overall survival, disease-free survival, and biochemical cure. RESULTS: Sixty-seven patients were included. The majority presented with early T-stage disease. Fifty (76%) patients were N0 at presentation. Seventeen (24%) had some evidence of neck disease on clinical examination or imaging. Forty (71%) achieved biochemical cure, and the 5-year biochemical recurrence-free survival for those cases was 86.5%. Among patients who had successful resection of all gross disease, 92% had no evidence of structural disease at 5 years. Overall survival was 91% at 5 years. Increased pre-operative calcitonin (Ct) level, primary tumor size, extrathyroidal extension, and neck metastases decrease the rate of biochemical cure. Larger tumor size increases the risk of structural disease recurrence and biochemical relapse after initial cure. The presence and number of neck metastases correlate with biochemical relapse. The presence of lateral neck nodes (pN1b) does not have different survival implications than centrally confined disease (pN1a). CONCLUSION: This study shows increasing tumor size, increased Ct level, and cervical metastases are poor prognostic factors. Patients with large tumors, high Ct level, or unfavorable pathologic findings may warrant more aggressive initial treatment, although limitations of the study prevent any conclusion regarding the effect of neck dissection. ABBREVIATIONS: ATA = American Thyroid Association BRFS = biochemical recurrence-free survival CND = central neck dissection Ct = calcitonin DFS = disease-free survival MTC = medullary thyroid carcinoma OR = odds ratio OS = overall survival pCND = prophylactic CND.

Effect of a Documentation Improvement Program for an Academic Otolaryngology Practice.

IMPORTANCE: Physicians recognize the value of accurate documentation to facilitate patient care, communication, and the distribution of professional fees. However, the association between inpatient documentation, hospital billing, and quality metrics is less clear. OBJECTIVES: To identify areas of deficiency in inpatient documentation and to instruct health care professionals on how to improve the quality and accuracy of clinical records. DESIGN, SETTING, AND PARTICIPANTS: A single-arm pre-post study was conducted from January 1, 2013, to December 31, 2014, among 17 attending and 12 resident physicians treating 1188 patients at an academic medical center. Data from 1 year prior to the intervention were compared with data for 10 months following the intervention. All increases were analyzed as a percentage increase after the intervention relative to before the intervention. INTERVENTIONS: Areas for improvement were identified, and all physicians in the department received education on inpatient coding and documentation. MAIN OUTCOMES AND MEASURES: The capture rate for complications or comorbidities and major complications or comorbidities, the case mix index (the average diagnosis related group relative weight for a hospital or department), and severity of illness and risk of mortality scores. RESULTS: A total of 1188 inpatients were included in the analysis: 743 in the preintervention period and 445 in the postintervention period. Review of our documentation identified major areas of comorbidity that were frequently underreported. Inadequate nutrition diagnoses (moderate malnutrition, severe protein-calorie malnutrition) were most often underreported. In addition, we found inadequate documentation supporting the presence of neck metastases. Among 1188 patients, the case mix index increased 5.3% (from 2.81 to 2.96) after the intervention, but this was not a statistically significant difference (P = .21). The normalized case mix index increased 21.7% (from 37.3 to 45.4; P < .01). The percentage of patients with a documented complication or comorbidity or major complication or comorbidity increased 27.1% (from 50.2% to 63.8%; P < .01). The percentage of patients assigned a severity of illness score of 3 or 4 increased 24.3% (from 34.7% to 43.0%; P < .01). The percentage of patients assigned a risk of mortality score of 3 or 4 increased 32.1% (from 18.7% to 24.7%; P = .01). CONCLUSIONS AND RELEVANCE: After educational sessions, multiple measures of patient acuity increased significantly owing to improved documentation of common comorbid conditions. Although physicians intuitively appreciate the importance of good documentation, education on the technical aspects of coding can significantly improve the quality and accuracy of clinical records.

Attitudes on and usage of balloon catheter technology in rhinology: A survey of the American Rhinologic Society.

INTRODUCTION: Use of balloon catheter dilation in the management of paranasal sinus diseases, including chronic rhinosinusitis (CRS) and recurrent acute rhinosinusitis, remains controversial. In an effort to gain some clarity about its evolving role, we surveyed members of the American Rhinologic Society (ARS). METHOD: Online survey. RESULTS: ARS Members were sent an invitation by e-mail to participate in an online, anonymous 23-item survey. A total of 231 participants completed the survey, for an overall response rate of 25%. Balloon catheter technology (BCT) played no role in the practices of one-third of all the respondents. Of those who did use BCT, more than 50% performed only 1-4 cases per month on average. This did not differ significantly with practice type (p = 0.2988). The overall use of BCT differed between types of practices with those in private practice reporting greater use of the technology for maxillary and sphenoid sinuses (p = 0.0003 and p = 0.0073, respectively). Participants in private practice appeared significantly more impressed with the results of BCT when compared with those in academia (p = 0.0005) and also thought that patients were more satisfied (p = 0.0002). Opinions toward the strength of available evidence also differed significantly between the two groups (p = 0.0007). Thirty-two respondents had experienced a complication with BCT, although the majority of these did not require any intervention. CONCLUSIONS: ARS members surveyed used BCT infrequently in their practices. Attitudes on the role of this technology in CRS management differed between academic and private practitioners, but, despite this, the volume of reported BCT use was the same. Surgeons are more accepting of the technology now compared with 5 years ago, and many of them believe that their use of BCT will increase in the future.

High Grade (Large Cell) Neuroendocrine Carcinoma of the Nasopharynx: Novel Case Report with Touch Preparation Cytology and Positive EBV Encoded Early RNA.

Fewer than five case reports of primary large cell neuroendocrine carcinoma of the nasopharynx are known to the authors. No previous reports have included examples of cytomorphology or have proven association with Epstein-Barr virus. We herein illustrate MRI findings, histopathologic features, immunohistochemical characterization, cytologic details, and in situ hybridization studies from a unique case of primary large cell neuroendocrine carcinoma of the nasopharynx in a 38-year-old Caucasian male patient. Recognition of rare tumor types of the nasopharynx allows for refinements in disease management and prognostication.

Hearing preservation in Guinea pigs with long-standing endolymphatic hydrops.

HYPOTHESIS: Interruption of the excitotoxic and inflammatory pathways implicated in endolymphatic hydrops (ELH)-associated hearing loss (HL) should afford hearing protection at the neuronal level. BACKGROUND: Previous work in our laboratory in the mouse model of ELH shows that dimethyl sulfoxide (DMSO), an anti-inflammatory solvent, can slow the progression of HL before neuronal degeneration occurs. Riluzole, a glutamate release inhibitor, may provide synergistic benefit. This study was designed to quantify the effects of DMSO and riluzole in a long-term model. METHODS: Guinea pigs with surgically induced ELH were sorted into 3 groups: riluzole+DMSO (Group 1), DMSO alone (Group 2), and untreated controls (Group 3). Animals in Groups 1 and 2 received daily injections of the study drug(s). All animals underwent auditory-evoked brainstem response evaluation every 4 weeks until 24 weeks, when they were sacrificed. Cochleae were preserved; spiral ganglion density was quantified. Animals without hydrops were excluded from the study as surgical failures. RESULTS: Animals from all groups developed unilateral HL. At the end of the experiment, HL was significantly lower in Group 1 relative to Group 3 (p = 0.049) and trended toward lower in Group 2 relative to Group 3 (p = 0.097). Groups 1 and 2 were not different (p = 0.311). At the cellular level, there is no evidence of neuronal degeneration in either treated group, whereas there is a significant neuronal degeneration in the untreated group. CONCLUSION: These results confirm the hearing protection observed with DMSO in short-term studies. However, unlike the previous study, which showed no additive benefit to riluzole, the combined treatment group in this study showed a hearing-protective effect at 24 weeks. This indicates a potential additive benefit conferred by riluzole toward long-term hearing protection. The study also finds evidence of statistically significant neuronal protection with both treatment groups. Overall, study provides additional evidence that DMSO and riluzole may preserve or slow the long-term progression of ELH-associated HL.

Pharmacological protection of hearing loss in the mouse model of endolymphatic hydrops.

OBJECTIVES/HYPOTHESIS: Excitotoxic and related inflammatory injury are implicated in the spiral ganglion degeneration seen with Meniere's disease and endolymphatic hydrops (ELH). Excitotoxicity is initiated with glutamate elevation and associated with downstream increases in reactive oxygen species resulting in inflammation-mediated neuronal degeneration. This study tests the hypothesis that interruption of the initial and/or downstream aspects of excitotoxicity should provide hearing protection in ELH-associated hearing loss. STUDY DESIGN: This study tests whether riluzole, a glutamate release inhibitor, and dimethylsulfoxide (DMSO), an anti-inflammatory and antioxidant solvent with favorable properties at the level of glutamate receptors, can protect against early-stage hearing loss in a mouse model of ELH. METHODS: The Phex(Hyp-Duk) mouse spontaneously develops ELH and postnatal hearing loss. Starting at postnatal day 6 (P6), daily injections of riluzole + DMSO or just DMSO were administered. Untreated mutants served as controls. At P21, P25, and P30, hearing function was assessed by recording auditory brainstem responses. A cochlear function index was developed to assess global cochlear function at each time point. RESULTS: Compared to no treatment, DMSO provided significant hearing protection (P < .05). The riluzole + DMSO also showed protection, but it was statistically indistinguishable from DMSO alone; a synergistic increase in protection with riluzole was not observed. CONCLUSIONS: This study demonstrates pharmacological hearing protection in an animal model of ELH. The results support the assertion that inflammatory (reactive oxygen species) injury, which is part of the excitotoxic pathway, contributes to the development of ELH-associated hearing loss.

Surgical induction of endolymphatic hydrops by obliteration of the endolymphatic duct.

Surgical induction of endolymphatic hydrops (ELH) in the guinea pig by obliteration and obstruction of the endolymphatic duct is a well-accepted animal model of the condition and an important correlate for human Meniere's disease. In 1965, Robert Kimura and Harold Schuknecht first described an intradural approach for obstruction of the endolymphatic duct (Kimura 1965). Although effective, this technique, which requires penetration of the brain's protective covering, incurred an undesirable level of morbidity and mortality in the animal subjects. Consequently, Andrews and Bohmer developed an extradural approach, which predictably produces fewer of the complications associated with central nervous system (CNS) penetration.(Andrews and Bohmer 1989) The extradural approach described here first requires a midline incision in the region of the occiput to expose the underlying muscular layer. We operate only on the right side. After appropriate retraction of the overlying tissue, a horizontal incision is made into the musculature of the right occiput to expose the right temporo-occipital suture line. The bone immediately inferio-lateral the suture line (Fig 1) is then drilled with an otologic drill until the sigmoid sinus becomes visible. Medial retraction of the sigmoid sinus reveals the operculum of the endolymphatic duct, which houses the endolymphatic sac. Drilling medial to the operculum into the area of the endolymphatic sac reveals the endolymphatic duct, which is then packed with bone wax to produce obstruction and ultimately ELH. In the following weeks, the animal will demonstrate the progressive, fluctuating hearing loss and histologic evidence of ELH.

Spiral ganglion loss outpaces inner hair cell loss in endolymphatic hydrops.

OBJECTIVES/HYPOTHESIS: Neuronal toxicity is thought to be important in Meniere's disease and experimental endolymphatic hydrops (ELH). This study quantifies the relationship between neuronal degeneration and hair cell degeneration in ELH to evaluate the hypothesis that a primary neural insult would yield greater loss in the spiral ganglion than at the inner hair cell level. STUDY DESIGN: Following induction and histopathologic confirmation of endolymphatic hydrops in guinea pigs, the degree of hydrops, spiral ganglion loss, and hair cell degeneration were quantified and compared. METHODS: Guinea pigs with surgically induced unilateral hydrops were sacrificed and their cochleas preserved. Hydrops severity and spiral ganglion density were quantified using automated methods. Hair cells were counted manually. Values were normalized against the contralateral ear to create loss indexes. RESULTS: Inner hair cell (IHC) loss at the apex is significantly lower than corresponding neuronal loss. IHC loss at the base is also lower than neuron loss, although not significantly. Regression analysis shows a significant, positive correlation between neuron loss severity and IHC loss severity at the apex, but not at the base. There is no correlation between hydrops severity and inner hair cell loss. CONCLUSIONS: By confirming that spiral ganglion loss is more severe than hair cell loss, and that hair cell loss appears to worsen with neuronal degeneration, this study supports the theory that neuronal toxicity is the primary insult in ELH-related disorders, such as Meniere's disease, and may provide the basis for designing treatment strategies.