Oldenburg, Michael

AbstractObjectives/HypothesisCompare proteomic profiles of rabbit vocal folds (VFs) injected with micronized cross‐linked jellyfish collagen “collagen Type 0” (MX‐JC) against two clinical products for injection medialization laryngoplasty (IL).Study DesignAnimal model.MethodsLeft recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received (MX‐JC) and adipose‐derived stem cells (ADSCs), Group 2, MX‐JC alone; Group 3, cross‐linked hyaluronic acid; and Group 4, micronized acellular dermis. Animals were sacrificed at 4 and 12 weeks. Proteomic profiling of injected versus noninjected VFs by nano‐liquid chromatography, tandem mass spectrometry, and reactome gene ontology analysis was performed.ResultsOverall, 37–61 proteins were found to be upregulated and 60–284 downregulated in injected versus non‐injected VFs (>1.5 fold, false discovery rate‐adjusted p < .05). Over‐representation analysis (% of total) revealed top up‐regulated pathways at 4 and 12 weeks, respectively: Group 1, keratan sulfate metabolism (46%) and cellular processes (29%); Group 2, extracellular matrix (ECM)/collagen processes (33%) and beta oxidation (39%); Group 3, cellular processes (50%) and energy metabolism (100%); and Group 4, keratan sulfate metabolism (31%) and inflammation (50%). Top downregulated pathways were: Group 1, Inflammation (36%) and glucose/citric acid metabolism (42%); Group 2, cell signaling (38%) and glucose/citric acid metabolism (35%); Group 3, keratan sulfate metabolism (31%) and ECM/collagen processes (48%); and Group 4, glucose/citric acid metabolism (33%) and ECM/collagen processes (43%).ConclusionsMX‐JC “collagen Type 0” upregulates pathways related to ECM/collagen formation and downregulates pathways related to inflammation suggesting that it is promising biomaterial for IL.Level of EvidenceNA

AbstractObjectivesTo examine the degree of agreement between MRI and histologically generated volumetric measurements of residual injection laryngoplasty material.MethodsFollowing left recurrent laryngeal nerve transection, rabbit vocal cords were injected with jellyfish collagen, Cymetra®, or Restylane®. Laryngeal tissue was harvested 4 or 12 weeks post injection followed by MRI imaging and histologic cross‐sectioning. Two raters estimated the volume of remaining injection material in specimens within MRI and histologic axial cross sections. Wilcoxon signed rank tests were employed to detect gross differences between inter‐rater measurements and between imaging modalities across time. Agreement between rater measurements and imaging (histology and MRI) was assessed using intra‐class correlation coefficients.ResultsData was available from 16 rabbits sacrificed at 4 weeks (n = 8) and 12 weeks (n = 8). Inter‐rater testing of MRI imaging revealed no significant differences (p > .05) between rater measurements across time points, and excellent agreement (0.93; 95% confidence interval 0.80–0.98) while histologically estimated volumes demonstrated a significant difference at 4 weeks (p < .05) and overall good agreement (0.89; 95% confidence interval 0.59–0.97). Comparison of MRI and histologically estimated volume measurements revealed significant differences at the 4‐week time point (p < .05) but not at 12 weeks (p > .05). Overall, there is only moderate agreement between MRI and histology estimates (0.72; 95% confidence interval 0.22–0.90).ConclusionsMRI imaging demonstrates good reliability and similar estimates of volume to histologically estimated measurements of residual injection laryngoplasty material at time points clinically relevant for future injection laryngoplasty experiments.Level of EvidenceNA.

AbstractObjectives/HypothesisTest a new jellyfish collagen biomaterial aimed to increase duration of injection medialization laryngoplasty (IL) against two products in clinical practice.Study DesignAnimal model.MethodsLeft recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received micronized cross‐linked jellyfish collagen (MX‐JC) and adipose derived stem cells (ADSCs), Group 2, MX‐JC alone, Group 3, cross‐linked hyaluronic acid (X‐HA), and Group 4, micronized acellular dermis (MACD). Animals were sacrificed at 4 and 12 weeks. Major outcomes were MRI tissue volumes and histopathology.ResultsAfter 100 μL IL MRI volumes (means ± STD) at 4 and 12 weeks were: Group 1: 27.2 ± 15.6 and 13.1 ± 5.2 μL, Group 2: 60.8 ± 18 and 27.8 ± 2.47 μL, Group 3: 27.4 ± 12 and 10.6 ± 8 μL, and Group 4: 37.5 ± 11 and 9.85 ± 1 μL. Group 2 volumes were largest and Group 3 were smallest in all comparisons (P < .05). Histologically, low grade inflammatory responses were observed in Group 1, mild histiocytic infiltration in Group 2, widespread muscle fiber loss in Group 3, and plasmocytic infiltration in Group 4.ConclusionsMX‐JC showed the least resorption at 4 and 12 weeks among all groups. T cell inflammatory responses were observed with MX‐JC but were reduced by 12 weeks while B cell immune responses, indicative of antibody priming, were predominantly noted with MACD. MX‐JC + ADSC showed low grade immunity while the XHA showed greater myocyte loss compared to the other groups.Level of EvidenceNA Laryngoscope, 131:E2452–E2460, 2021

OBJECTIVERadiation dose to the cochlea has been proposed as a key prognostic factor in hearing preservation following stereotactic radiosurgery (SRS) for vestibular schwannoma (VS). However, understanding of the predictive value of cochlear dose on hearing outcomes following SRS for patients with non-VS tumors of the lateral skull base (LSB) is incomplete. The authors investigated rates of hearing loss following high-dose SRS in patients with LSB non-VS lesions compared with patients with VS.METHODSPatients with LSB meningioma or jugular paraganglioma and serviceable pretreatment hearing who underwent SRS treatment during 2007–2016 and received a modiolus dose > 5 Gy were included in a retrospective cohort study, along with a similarly identified control group of consecutive patients with sporadic VS.RESULTSSixteen patients with non-VS tumors and a control group of 43 patients with VS met study criteria. Serviceable hearing, defined as American Academy of Otololaryngology–Head and Neck Surgery class A/B, was maintained in 13 non-VS versus 23 VS patients (81% vs 56%, p = 0.07). All 3 instances of hearing loss in non-VS patients were observed in cerebellopontine angle (CPA) meningiomas. Non-VS with preserved hearing had a median modiolus dose of 6.9 Gy (range 5.7–19.2 Gy), versus 7.4 Gy (range 5.4–7.6 Gy) in those patients with post-SRS hearing loss (p = 0.53). Sporadic VS patients received an overall median modiolus point-dose of 6.8 Gy (range 5.4–11.7 Gy).CONCLUSIONSThe modiolus dose threshold of 5 Gy does not predict hearing loss in patients with non-VS tumors undergoing SRS, suggesting that dosimetric parameters derived from VS may not be applicable to this population. Differential rates of hearing loss appear to vary by pathology, with paragangliomas and petroclival meningiomas demonstrating decreased risk of hearing loss compared to CPA meningiomas that may directly compress the cochlear nerve similarly to VS.

Objectives/HypothesisVocal fold (VF) paralysis by sectioning the recurrent laryngeal nerve dramatically impacts the life of thyroidectomy patients. Volume‐expanding materials can temporarily restore VF medialization. To prolong this benefit, adipose mesenchymal stem cells (ADSCs) and micronized acellular dermis (MACD) were co‐injected in a rabbit model of injection medialization laryngoplasty. Biomarkers of in situ proliferation were identified by mass spectrometry proteomics and pathway analysis to guide future efforts to increase the length of benefit.MethodsADSCs were expanded and/or differentiated into chondrocytes (CHON) as collagen microspheres. After VF paralysis rabbits received MACD, MACD + undifferentiated ADSC, or MACD+CHON, ADSCs differentiated into chondrocytes. After 12 weeks, animals were sacrificed and 5‐µm paraffin‐embedded cryosections were prepared from larynges for hematoxylin and eosin visualization and nanoflow liquid chromatography electrospray‐ionization tandem‐mass spectrometry analysis of tissue collections. Validated proteins were processed by Venn subtraction and gene ontology (GO) overrepresentation analysis to identify unique pathways and biomarkers.ResultsConfirmed proteins numbered 147 (MACD), 1,243 (MACD+ADSC), and 1,033 (MACD+CHON). Totally, 333 proteins were uniquely found in the MACD+ADSC group, including mesenchymal surface markers CD9, CD44, fibronectin, and vimentin. Over 70% of proteins belonged to catalytic activity and binding GO categories, with the histone (H) family being overrepresented (P < 0.05). Histone variants H3.3, H2A.V, and H2A.Z (associated with open chromatin states) were overrepresented in the MACD+ADSC group, whereas structural histones H2A, H2B, and H4 were not.ConclusionBiomarkers, including atypical histones, are associated with in vivo proliferation of ADSCs and an expanded VF medialization volume.Level of EvidenceNA Laryngoscope, 128:E402–E408, 2018

Objectives/HypothesisDesign and test a novel biomaterial for injection laryngoplasty aimed to increase the duration of effectiveness of micronized acellular dermis.Study DesignAnimal model.MethodsInjection laryngoplasty was performed in three groups (n = 5) of New Zealand White rabbits. Acellular dermis was either used alone as a control (group 1), was combined with undifferentiated stem cells (group 2), or with predifferentiated chondrocytic cells (group 3). Groups 2 and 3 were supplemented with growth factors. Animals were sacrificed 4 and 12 weeks after laryngoplasty and histologic analysis was completed. The major outcome measure was volume of tissue remaining.ResultsAfter 4 weeks, the mean volume of tissue remaining was 341 ± 89 mm3, 295 ± 102 mm3, and 133 ± 15 mm3, for groups 1 to 3, respectively. At the 12‐week time point, volumes were 62 ± 62 mm3, 235 ± 35 mm3, and 107 ± 99 mm3. After 12 weeks, there was a significantly higher volume in group 2 compared to group 1 or 3 (P = .01, P = .04). Volumes between week 4 and week 12 were significantly lower in group 1 (P = .02), but not significantly different for groups 2 and 3 (P = .38, P = .74). Histologic evaluation revealed a robust lymphocytic infiltration in all cases as well as morphologic and immunophenotypic features suggestive of chondrogenic differentiation in a single animal.ConclusionsMicronized acellular dermis combined with stem cells and growth factors showed significantly less resorption 12 weeks after injection laryngoplasty compared to micronized acellular dermis alone. Groups using novel tissue‐engineered biomaterial showed a lower resorption rate over time compared with acellular dermis alone.Level of EvidenceNA. Laryngoscope, 128:160–167, 2018

Objective Report two positive sentinel node biopsies for sinonasal melanoma. Design Retrospective review. Setting Academic tertiary care center. Participants Patients who underwent sentinel node biopsy for sinonasal melanoma between November 1, 2014 and November 1, 2015. Main Outcome Measures Clinical course. Results Two patients were identified. Patient 1 (83M) presented with a sinonasal melanoma anterior to the left inferior turbinate and was clinically N0 neck. Lymphoscintigraphy revealed two sentinel nodes in the ipsilateral and three in the contralateral cervical basins. The left level I sentinel node was positive for melanoma and lymphadenectomy showed no additional metastases.Patient 2 (71F) presented after incomplete resection of a sinonasal melanoma of the left posterior maxillary sinus wall and was clinically N0 neck. Lymphoscintigraphy with single-photon emission computed tomography (SPECT/CT) localization revealed one sentinel node in the parapharyngeal space and another in the ipsilateral cervical basin. Metastatic melanoma was found in both nodes and completion lymphadenectomy was negative for additional disease.Both patients developed distant metastasis in less than 1 year after surgical resection but responded well to adjuvant immunomodulatory chemotherapeutic agents. Conclusion Sentinel node biopsy for sinonasal melanoma can provide crucial clinical evidence of regional metastasis prior to overt clinical signs and symptoms. This intraoperative tool has the potential to improve detection of regional metastasis and improve long-term outcomes of this aggressive malignancy.

Objectives/HypothesisMicronized AlloDerm is a commonly used injectable material for injection laryngoplasty; however, the histologic response to laryngeal implantation and resorption rate over time have not been elucidated. This study aimed to evaluate the in vivo response of micronized AlloDerm over time after laryngeal implantation using a rabbit model.Study DesignAnimal model.MethodsThe left recurrent laryngeal nerve was sectioned in five New Zealand White rabbits to create a vocal cord paralysis. Two weeks later, injection laryngoplasty was performed with 100 μL of micronized AlloDerm. Animals were sacrificed 4 (two rabbits) and 12 (three rabbits) weeks after injection. Histologic sections were stained and evaluated by a single pathologist. Volume estimates were made by assuming the implant took an ellipsoid shape using dimensions calculated from histologic slides.ResultsIn all cases, histological analysis revealed a lymphocytic inflammatory response infiltrating the peripheral margins of injection. After 4 weeks, the volume of injected material remaining in two rabbits was 404 and 278 mm3 (average 341 mm3). After 12 weeks, the volume of injected material remaining in three rabbits was 0, 61, and 124 mm3 (average 62 mm3), an 82% difference in volume of material between animals sacrificed at 4 weeks versus 12 weeks.ConclusionsInjection laryngoplasty using micronized AlloDerm induces a lymphocytic inflammatory response after injection in a rabbit model. Though a significant amount of material remains after 4 weeks, by 12 weeks the majority has been reabsorbed.Level of EvidenceNA Laryngoscope, 127:E166–E169, 2017