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Rationale: Understand the impact of insurance coverage on sleep apnea outcomes for patients awaiting upper airway stimulation.Objectives: Examine the natural history of impact of upper airway stimu...

OBJECTIVE/HYPOTHESIS The ADHERE Registry is a multicenter prospective observational study following outcomes of upper airway stimulation (UAS) therapy in patients who have failed continuous positive airway pressure therapy for obstructive sleep apnea (OSA). The aim of this registry and purpose of this article were to examine the outcomes of patients receiving UAS for treatment of OSA. STUDY DESIGN Cohort Study. METHODS Demographic and sleep study data collection occurred at baseline, implantation visit, post-titration (6 months), and final visit (12 months). Patient and physician reported outcomes were also collected. Post hoc univariate and multivariate analysis was used to identify predictors of therapy response, defined as ≥50% decrease in Apnea-Hypopnea Index (AHI) and AHI ≤20 at the 12-month visit. RESULTS The registry has enrolled 1,017 patients from October 2016 through February 2019. Thus far, 640 patients have completed their 6-month follow-up and 382 have completed the 12-month follow-up. After 12 months, median AHI was reduced from 32.8 (interquartile range [IQR], 23.6-45.0) to 9.5 (IQR, 4.0-18.5); mean, 35.8 ± 15.4 to 14.2 ± 15.0, P

Objective: An increasing number of facilities offer Upper Airway Stimulation (UAS) with varying levels of experience. The goal was to quantify whether a surgical learning curve exists in operative or sleep outcomes in UAS. Methods: International multi-center retrospective review of the ADHERE registry, a prospective international multi-center study collecting UAS outcomes. ADHERE registry centers with at least 20 implants and outcomes data through at least 6-month follow-up were reviewed. Cases were divided into two groups based on implant order (the first 10 or second 10 consecutive implants at a given site). Group differences were assessed using Mann-Whitney U-tests, Chi-squared tests, or Fisher’s Exact tests, as appropriate. A Mann-Kendall trend test was used to detect if there was a monotonic trend in operative time. Sleep outcome equivalence between experience groups was assessed using the two one-sided tests approach. Results: Thirteen facilities met inclusion criteria, contributing 260 patients. Complication rates did not significantly differ between groups ( P = .808). Operative time exhibited a significant downward trend ( P Conclusions: Across the centers’ first 20 implants, an approximately 11% reduction operative time was identified, however, no learning curve effect was seen for 6-month or 12-month AHI or ESS over the first twenty implants. Ongoing monitoring through the ADHERE registry will help measure the impact of evolving provider and patient specific characteristics as the number of implant centers increases.

The severe acute respiratory syndrome (SARS)‐CoV‐2 pandemic continues to produce a large number of patients with chronic respiratory failure and ventilator dependence. As such, surgeons will be called upon to perform tracheotomy for a subset of these chronically intubated patients. As seen during the SARS and the SARS‐CoV‐2 outbreaks, aerosol‐generating procedures (AGP) have been associated with higher rates of infection of medical personnel and potential acceleration of viral dissemination throughout the medical center. Therefore, a thoughtful approach to tracheotomy (and other AGPs) is imperative and maintaining traditional management norms may be unsuitable or even potentially harmful. We sought to review the existing evidence informing best practices and then develop straightforward guidelines for tracheotomy during the SARS‐CoV‐2 pandemic. This communication is the product of those efforts and is based on national and international experience with the current SARS‐CoV‐2 pandemic and the SARS epidemic of 2002/2003.

We describe the first documented case of sinking skin flap syndrome (SSFS) following head and neck cancer resection with free flap reconstruction. This rare syndrome, also known as “syndrome of the trephined,” is an uncommon complication typically seen after decompressive craniectomy prior to cranioplasty. Thought to be related to atmospheric pressure and gravity overwhelming intracranial pressure, the scalp is displaced inward, and cortical compression can occur over the surgical site, leading to neurologic changes (e.g. headache, mental status changes, seizures, focal deficits) as well as dysautonomia. A 58-year-old male underwent wide local excision of a large, advanced squamous cell carcinoma of the scalp that required craniectomy and dural resection, followed by reconstruction with a latissimus dorsi myofascial free flap and overlying meshed skin graft. On post-operative day 11, he developed acute right hemiparesis with right facial droop, altered mental status, hypotension and bradycardia, with subsequent CT of the head supporting a diagnosis of sinking skin flap syndrome. He improved within 48 hours with conservative treatment, without long term sequelae. While this is a rare phenomenon, it is important to keep sinking skin flap syndrome in the differential diagnosis for patients who develop neurologic changes or autonomic dysfunction following calvarial resection with soft tissue free flap reconstruction.

To examine whether previous palate or hypopharyngeal surgery was associated with efficacy of treatment of obstructive sleep apnea with hypoglossal nerve stimulation.Cohort (retrospective and prospective).Eleven academic medical centers.Adults treated with hypoglossal nerve stimulation were enrolled in the ADHERE Registry. Outcomes were defined by the apnea-hypopnea index (AHI), in 3 ways: change in the AHI and 2 definitions of therapy response requiring ≥50% reduction in the AHI to a level20 events/h (Response20) or 15 events/h (Response15). Previous palate and hypopharyngeal (tongue, epiglottis, or maxillofacial) procedures were documented. Linear and logistic regression examined the association between previous palate or hypopharyngeal surgery and outcomes, with adjustment for age, sex, and body mass index.The majority (73%, 217 of 299) had no previous palate or hypopharyngeal surgery, while 25% and 9% had previous palate or hypopharyngeal surgery, respectively, including 6% with previous palate and hypopharyngeal surgery. Baseline AHI (36.0 ± 15.6 events/h) decreased to 12.0 ± 13.3 at therapy titration (Previous upper airway surgery was not clearly associated with efficacy of hypoglossal nerve stimulation.

ObjectiveTo evaluate the impact of age on safety, efficacy, and usage of upper airway stimulation (UAS).Study DesignMulticenter observational study.SettingThirteen US hospitals and 3 German hospitals.Subjects and MethodsThe ADHERE registry is a multicenter database enrolling patients undergoing UAS implantation from October 2016 to April 2018. Outcome measures included the Epworth Sleepiness Scale, apnea-hypopnea index (AHI), therapy usage, and complications. Data were segmented by age (

Diverticula of the hypopharynx have been recognized for over 200 years. Zenker’s diverticulum (ZD) is by far the most common with an annual incidence of 2/100,000 individuals. Specifically, ZD is an outpouching of hypopharyngeal mucosa that protrudes through a weak area at the junction of the inferior constrictor muscle and the cricopharyngeus (CP) muscle, known as Killian’s dehiscence. Historically, ZD was first recognized by Abraham Ludlow in 1796 and was named after a German pathologist, Friedrich Albert Zenker, who reported a series of ZD patients in 1877. Wheeler reported the first successful open repair of a ZD in 1882. In 1917, Mosher first introduced the concept of endoscopic treatment of ZD that has now seen tremendous advances with respect to both instrumentation and technique. The most common method used for treatment of ZD, the endoscopic staple-assisted approach, was first reported by Collard in 1993. Since then, several retrospective studies have found both open and endoscopic techniques to be highly effective with comparable complication rates and lengths of hospital stay.

The purpose of this study was to assess the potential of U.S. Food and Drug Administration-cleared devices designed for indocyanine green-based perfusion imaging to identify cancer-specific bioconjugates with overlapping excitation and emission wavelengths. Recent clinical trials have demonstrated potential for fluorescence guided surgery, but the time and cost of the approval process may impede clinical translation. To expedite this translation, we explored the feasibility of repurposing existing optical imaging devices for fluorescence-guided surgery. Methods: Consenting patients (n = 15) scheduled for curative resection were enrolled in a clinical trial evaluating the safety and specificity of cetuximab-IRDye800 (NCT01987375). Open-field fluorescence imaging was performed preoperatively and during the surgical resection. Fluorescence intensity was quantified using integrated instrument software, and the tumor-to-background ratio characterized fluorescence contrast. Results: In the preoperative clinic, the open-field device demonstrated potential to guide preoperative mapping of tumor borders, optimize the day of surgery, and identify occult lesions. Intraoperatively, the device demonstrated robust potential to guide surgical resections, as all peak tumor-to-background ratios were greater than 2 (range, 2.2-14.1). Postresection wound bed fluorescence was significantly less than preresection tumor fluorescence (P

OBJECTIVE Examine the patient characteristics of those undergoing upper airway stimulation (UAS) for the treatment of continuous positive airway pressure (CPAP)-refractive obstructive sleep apnea (OSA) at a tertiary care medical center to determine objective clinical predictors of success. METHODS Retrospective chart review of the first 25 consecutive patients between August 2015 and December 2016 treated with UAS at a tertiary care academic center. Demographic data, medical and sleep history, pre- and postoperative polysomnography data, and sleep endoscopy findings were collected. Statistical analysis was performed using two-sided t test with bivariate and linear regression analysis. RESULTS In our cohort of 25 patients, mean age was 67.5 ± 7.6 years, and mean body mass index (BMI) was 28.2 ± 3.8 kg/m2 with 42% female. One patient was excluded from analysis for unmasking of complete central apnea with therapy. AHI decreased by a mean of 33.8 events/hour following treatment (95% confidence interval: 25.8 to 41.7, P < 0.001). Preintervention AHI was associated with therapy response, with each point of preintervention AHI leading to an average decrease of 1.03 points (P < 0.001). Eighty-three percent of patients achieved a treatment AHI < 5, whereas 92% achieved an AHI < 10. Mean device use was 49.5 ± 10.4 hours per week. Ninety-two percent of patients were discharged the day of surgery. No major adverse events occurred. CONCLUSION UAS continues to gain popularity for the treatment of CPAP-refractive OSA; therefore, identification of predictors of success is crucial. Our study, although small, suggests that more severe preintervention AHI does not preclude significant therapy response and may expand the inclusion criteria for UAS, meriting further investigation. LEVEL OF EVIDENCE 4 Laryngoscope, 130:556-560, 2020.

Upper airway stimulation (UAS) has been shown to reduce severity of obstructive sleep apnoea. The aim of this study was to identify predictors of UAS therapy response in an international multicentre registry. Patients who underwent UAS implantation in the United States and Germany were enrolled in an observational registry. Data collected included patient characteristics, apnoea/hypopnoea index (AHI), Epworth sleepiness scale (ESS), objective adherence, adverse events and patient satisfaction measures. Post hoc univariate and multiple logistic regression were performed to evaluate factors associated with treatment success. Between October 2016 and January 2018, 508 participants were enrolled from 14 centres. Median AHI was reduced from 34 to 7 events·h−1, median ESS reduced from 12 to 7 from baseline to final visit at 12-month post-implant. In post hoc analyses, for each 1-year increase in age, there was a 4% increase in odds of treatment success. For each 1-unit increase in body mass index (BMI), there was 9% reduced odds of treatment success. In the multivariable model, age persisted in serving as statistically significant predictor of treatment success. In a large multicentre international registry, UAS is an effective treatment option with high patient satisfaction and low adverse events. Increasing age and reduced BMI are predictors of treatment response., In this largest international report to date, a substantial improvement in OSA severity in response to UAS is identified. Increasing age and reduced BMI are predictors of UAS. http://ow.ly/mtGa30mmTib

Objective Upper airway stimulation (UAS) is an alternative treatment option for patients unable to tolerate continuous positive airway pressure (CPAP) for the treatment of obstructive sleep apnea (OSA). Studies support the safety and efficacy of this therapy. The aim of this registry is to collect retrospective and prospective objective and subjective outcome measures across multiple institutions in the United States and Germany. To date, it represents the largest cohort of patients studied with this therapy. Study Design Retrospective and prospective registry study. Setting Ten tertiary care hospitals in the United States and Germany. Subjects and Methods Patients were included who had moderate to severe OSA, were intolerant to CPAP, and were undergoing UAS implantation. Baseline demographic and sleep study data were collected. Objective and subjective treatment outcomes, adverse events, and patient and physician satisfaction were reviewed. Results The registry enrolled 301 patients between October 2016 and September 2017. Mean ± SD AHI decreased from 35.6 ± 15.3 to 10.2 ± 12.9 events per hour ( P < .0001), and Epworth Sleepiness Scale scores decreased from 11.9 ± 5.5 to 7.5 ± 4.7 ( P < .0001) from baseline to the posttitration visit. Patients utilized therapy for 6.5 hours per night. There were low rates of procedure- and device-related complications. Clinical global impression scores demonstrated that the majority of physicians (94%) saw improvement in their patients' symptoms with therapy. The majority of patients (90%) were more satisfied with UAS than CPAP. Conclusions Across a multi-institutional registry, UAS therapy demonstrates significant improvement in subjective and objective OSA outcomes, good therapy adherence, and high patient satisfaction.

Background and Objective Fluorescence-guided imaging to assist in identification of malignant margins has the potential to dramatically improve oncologic surgery. However, a standardized method for quantitative assessment of disease-specific fluorescence has not been investigated. Introduced here is a ratiometric threshold derived from mean fluorescent tissue intensity that can be used to semi-quantitatively delineate tumor from normal tissue. Methods Open-field and a closed-field imaging devices were used to quantify fluorescence in punch biopsy tissues sampled from primary tumors collected during a phase 1 trial evaluating the safety of cetuximab-IRDye800 in patients (n = 11) undergoing surgical intervention for head and neck cancer. Fluorescence ratios were calculated using mean fluorescence intensity (MFI) from punch biopsy normalized by MFI of patient-matched tissues. Ratios were compared to pathological assessment and a ratiometric threshold was established to predict presence of cancer. Results During open-field imaging using an intraoperative device, the threshold for muscle normalized tumor fluorescence was found to be 2.7, which produced a sensitivity of 90.5% and specificity of 78.6% for delineating disease tissue. The skin-normalized threshold generated greater sensitivity (92.9%) and specificity (81.0%). Conclusion Successful implementation of a semi-quantitative threshold can provide a scientific methodology for delineating disease from normal tissue during fluorescence-guided resection of cancer. J. Surg. Oncol. 2015 111:2–8. © 2015 Wiley Periodicals, Inc.

Background Implantable hypoglossal nerve upper airway stimulation (HNS) is a novel strategy approved by the US Food and Drug Administration for the management of moderate-to-severe obstructive sleep apnea (OSA) in patients with continuous positive airway pressure therapy intolerance or failure. Because of the proximity of a cardiac implantable electronic device (CIED) to this stimulator, interaction between these devices is theoretically possible. Objective The purpose of this study was to assess interactions between an implantable HNS device and a CIED. Methods We retrospectively analyzed 14 ad hoc patients with continuous positive airway pressure-intolerant, moderate-to-severe OSA and pre-existing transvenous CIEDs undergoing HNS implantation (Inspire II, Inspire Medical Systems). We assessed these devices for their pre and postimplant OSA outcomes and for possible device–device interaction. All patients were followed up for 1 year. Results Of the 14 patients, 9 had a pacemaker (8 dual-chamber, 1 single-chamber), 4 had an implantable cardioverter-defibrillator (2 dual-chamber, 1 single-chamber), and 1 had a cardiac resynchronization therapy device. All the HNS devices were implanted on the opposite side of the CIED. All CIEDs were programmed bipolar. HNS were programmed either unipolar or bipolar. During implant, intraoperative testing was performed to confirm that bipolar and unipolar HNS stimulation did not impact CIED sensing. During the follow-up period, no oversensing episodes were noted on the CIEDs. Conclusion In this early experience, simultaneous use of a novel hypoglossal nerve upper airway stimulation device with transvenous CIEDs seems to be safe, effective, and without any device–device interactions.

The purpose of the current study was to compare outcomes and complication rates of sialolithiasis treated with intracorporeal holmium laser lithotripsy in conjunction with salivary endoscopy with those treated with simple basket retrieval or a combined endoscopic/open procedure.Case-comparison study.Tertiary hospital.Review of prospectively collected data of patients who underwent treatment for sialolithiasis by the senior author during 2011 to 2013. Patient demographics, operative techniques, surgical findings, clinical outcomes, and complications were recorded. Additional information regarding symptoms and satisfaction with treatment was obtained via standardized telephone questionnaire at the time of the data analysis.Thirty-one patients were treated for sialolithiasis. Sialoliths averaged 5.9 mm in size (range, 2-20 mm) and were comparable between both groups. Sixty-eight percent were in the submandibular gland (n = 21), with the remaining 32% in the parotid gland (n = 10). Fifty-two percent of patients (n = 16) were treated endoscopically with intracorporeal holmium laser lithotripsy, while the remaining 48% (n = 15) were treated with salivary endoscopy techniques other than laser lithotripsy. Successful stone removal without additional maneuvers occurred in 81% of the laser cases and 93% of the nonlaser group. Patients in the laser group reported an average improvement of symptoms of 95% compared with 90% of the nonlaser group when adjusted for outliers. Complications in all patients included ductal stenosis (n = 2) and salivary fistula (n = 1).The results of our series show favorable results with the use of intracorporeal holmium laser lithotripsy for the endoscopic management of sialolithiasis with minimal adverse events.

During fluorescence-guided surgery, a cancer-specific optical probe is injected and visualized using a compatible device intraoperatively to provide visual contrast between diseased and normal tissues to maximize resection of cancer and minimize the resection of precious adjacent normal tissues. Six patients with squamous cell carcinomas of the head and neck region (oral cavity (n=4) or cutaneous (n=2)) were injected with an EGFR-targeting antibody (Cetuximab) conjugated to a near-infrared (NIR) fluorescent dye (IRDye800) 3, 4, or 7 days prior to surgical resection of the cancer. Each patient’s tumor was then imaged using a commercially available, open-field NIR fluorescence imaging device each day prior to surgery, intraoperatively, and post-operatively. The mean fluorescence intensity (MFI) of the tumor was calculated for each specimen at each imaging time point. Adjacent normal tissue served as an internal anatomic control for each patient to establish a patient-matched “background” fluorescence. Resected tissues were also imaged using a closed-field NIR imaging device. Tumor to background ratios (TBRs) were calculated for each patient using both devices. Fluorescence histology was correlated with traditional pathology assessment to verify the specificity of antibody-dye conjugate binding. Peak TBRs using the open-field device ranged from 2.2 to 11.3, with an average TBR of 4.9. Peak TBRs were achieved between days 1 and 4. This study demonstrated that a commercially available NIR imaging device suited for intraoperative and clinical use can successfully be used with a fluorescently-labeled dye to delineate between diseased and normal tissue in this single cohort human study, illuminated the potential for its use in fluoresence-guided surgery.

Optical fluorescent technology has the potential to deliver real time imaging of cancer into the operating room and the clinic. To determine the efficacy of fluorescently labeled anti-vascular endothelial growth factor (VEGF) antibody to be used as a cancer specific optical contrast agent to guide surgical resections, we evaluated the sensitivity and specificity of this agent to detect microscopic residual disease in a preclinical model of head and neck squamous cell carcinoma (HNSCC). Using a flank murine model, mice were xenografted with SCC-1 tumor cells and injected with anti-VEGF antibody (bevacizumab) conjugated to an optically active fluorophore (Cy5.5). Tumors underwent sub-total resections and were assessed for the presence of residual disease by fluorescent stereomicroscopy. Expected positive and negative biopsies were taken according to the presence or absence of fluorescence, respectively. Histology was used to confirm the presence or absence of disease. Biopsies taken from areas of fluorescence within the wound bed (n=18) were found to be histologically malignant in all but one biopsy. Samples taken from a non-fluorescing tumor bed (n=15) were found to be histologically benign in 11 of 15. These findings correlated with a sensitivity and specificity of 80.9% and 91.7%, respectively. This data supports previous data presented by this group and supports further investigation of fluorescently labeled anti-tumor antibodies to detect disease in the surgical setting.

Objective The aim of this study is to determine the efficacy of indocyanine green (ICG) conjugated to antiepidermal growth factor receptor antibody (cetuximab) to image head and neck cancer. Study Design Mice (n = 3) were injected with unconjugated ICG and imaged at 100-second intervals for a total of 1000 seconds to assess imaging characteristics. Mice (n = 10) xenografted with SCC-1 cells were then systemically injected with cetuximab conjugated to indocyanine green and imaged over a 72-hour period. To assess the sensitivity and specificity, xenografted tumors underwent subtotal resections and then were assessed for residual disease by fluorescence stereomicroscopy and confirmed by histology. Results Tumors demonstrated excellent fluorescence 24 hours after injection of cetuximab-ICG. There was a direct relationship between fluorescence and the given dose of cetuximab-ICG. Following subtotal resection, we found fluorescence correlated with a sensitivity of 78.4% and specificity of 96%. Conclusions This study provides evidence that supports further preclinical investigation of cetuximab in the evaluation of surgical margins, but linkage to ICG lacks the sensitivity for use in a clinical setting.

Objectives:(1) Evaluate and compare the effectiveness of tongue depressors and the Dynasplint Trismus System to manage trismus in head and neck cancer patients. (2) Analyze factors that may indicate improved outcomes for patients in trismus management.Methods:Single-institution randomized controlled cross-over study (2007-2013). Fifty-three patients with trismus as a complication of cancer treatment were enrolled in the study at an academic tertiary care center. Twenty-seven patients were randomized to a treatment arm using Dynasplint, while 26 were enrolled in a treatment arm using tongue depressors to perform stretching exercises. The primary outcome was interval measurement of incisor-to-incisor opening during and at the completion of tongue depressor therapy compared to Dynasplint usage. Pretreatment and treatment characteristics, including type of cancer treatments used, were analyzed for association with rate of improvement.Results:Dynasplint and tongue depressors both significantly increased the ma...

Objectives:In the minimally invasive treatment of sialolithiasis, lasers can be used to fracture stones, allowing for the endoscopic extirpation of larger lesions. The purpose of the current study was to evaluate outcomes following the use of the holmium YAG laser for intracorporeal salivary lithotripsy.Methods:Review of prospectively collected data regarding patients who underwent interventional sialoendoscopy for sialolithiasis was performed, recording patient demographics, surgical findings, and clinical outcomes. Patients who were treated with intracorporeal laser lithotripsy were compared with those who had simple basket retrieval or endoscopic assisted open removal. Patients were surveyed by phone for current symptom follow-up.Results:Thirty-one patients (average age 56, range 14-84) were treated for sialolithiasis with endoscopic techniques at our academic institution from 2011-2012. Sialoliths averaged 5.9 mm in size (range 2-20mm), arising from the submandibular ducts (n=20), parotid (n=10), or b...

Objective: We sought to 1) assess the process required to implement a virtual interactive presence (VIP) system into a standard operating room setting, 2) evaluate the technical performance of the device, and 3) determine the potential utility of the system for guidance of surgical procedures.Method: A feasibility study was conducted at a teaching hospital in 2011. Patients scheduled to undergo otolaryngology procedures were recruited for VIPAAR system (Birmingham, AL) usage to perform standardized exercises during the case. Setup time and observations regarding performance of the system were recorded. Surveys assessing satisfaction level were completed by the staff.Results: Following informed consent, the VIP system was implemented in 8 otolaryngology procedures requiring rigid nasal endoscopy (n = 6) or laryngeal microscopy (n = 2). Average setup time was 4.5 minutes at the outset with an additional 2.4 minutes intraoperatively. One hundred percent of OR staff surveyed (n = 24) agreed that the system wa...

Objective: Salvage laryngectomy to treat organ preservation failures results in significantly higher local wound complications. Even in the absence of extralaryngeal disease, primary closure of laryngeal defects can result in protracted wound care problems. We hypothesize that even when sufficient mucosa is present to close the defect primarily, introduction of vascularized tissue to close the defect may improve outcomes. Design: Retrospective case-control study. Setting: Two academic tertiary care centers. Patients and Methods: Patients undergoing salvage surgery for laryngeal squamous cell carcinoma between 2000 to 2006 were considered for this study. Patients requiring total laryngopharyngectomy or partial pharyngectomy were excluded. There were 37 patients who met study criteria: 17 patients underwent free flap reconstruction (16 radial forearm flaps and 1 rectus flap), and 20 patients underwent primary closure. The median follow-up was 12 (range, 4–60) months. Previous treatment consisted of chemoradiation for 41% of the reconstruction group and 35% of the primary closure group; the remainder were treated with primary radiation alone. Main Outcome Measures: Pharyngocutaneous fistula, stricture, length of hospitalization, feeding tube dependence. Results: The free flap reconstruction group had a lower rate of fistula (18%) compared with the primary closure group (50%). A lower rate of stricture formation (18% vs. 25%) and feeding tube dependence (23% vs. 45%) was observed in the free flap reconstruction group compared with the primary closure group. The development of a fistula in either group resulted in a prolonged hospital stay (mean, 19 vs. 7 days) and additional procedures. Conclusion: Planned reconstruction of salvage laryngectomy defects with vascularized tissue is associated with a lower fistula rate and may improve outcomes.

Parathyromatosis is an uncommon cause of hypercalcemia. We describe a case of parathyromatosis and hypercalcemia in a 38-year-old man with a history of end-stage renal disease and subtotal parathyroidectomy in which a previous parathyroid operation was implicated. The results of fine-needle aspiration and histologic examination demonstrated a neck mass consistent with parathyromatosis. We discuss parathyromatosis as a rare cause of recurrent hypercalcemia in patients with end-stage renal disease and in those who have undergone previous parathyroid operations. We also characterize the iatrogenic and the embryologic pathogenetic factors involved.