Outcomes of regenerative treatment for over 200 patients with tympanic membrane perforation

OBJECTIVE

To evaluate outcomes of a regenerative treatment (RT) for over 200 patients with tympanic membrane perforation (TMP). The RT-TMP method involves a gelatin sponge, basic fibroblast growth factor (bFGF) and fibrin glue.

METHODS

The study population included 216 patients and 234 ears (male: female =100:116; age 1-93 years). All enrolled patients were treated with RT-TMP in which TMP edges were disrupted mechanically and a gelatin sponge immersed in bFGF was inserted into the perforation. Fibrin glue was then dripped over the sponge. Patient outcomes including TMP closure rates, change in hearing level, and complications were obtained from retrospective medical chart reviews. The TMP was examined three or more weeks after surgery. The treatment was repeated up to 4 times until complete TMP closure was achieved.

RESULTS

After mechanical disruption, the perforation size was Grade I, ≤1/3 of entire TM area in 22 ears (9.4 %), Grade II, 1/3-2/3 of entire TM in 77 ears (32.9 %) and Grade III, ≥2/3 of entire TM area in 135 ears (57.7 %). The overall TMP closure rates were 97.0 % (227/234). Complete TMP closure was achieved in 68.8 % (161/234), 22.6 % (53/234), 4.7 % (11/234) and 0.9 % (2/234) of ears after 1, 2, 3 and 4 treatments, respectively. In 7 of 234 ears (3.0 %), the TMPs were not closed completely after 4 treatments. There was no correlation between TMP size after mechanical disruption and number of treatments required to achieve complete closure (Fisher's exact test p = 0.70). The mean air-conduction hearing threshold at low frequency improved from 57.3 ± 16.7 dB before treatment to 37.3 ± 16.0 dB (p < 0.0001) after closure of TMPs. For middle and high frequencies, the improvement was 49.0 ± 19.3 dB to 36.9 ± 17.9 dB (p < 0.0001) and 57.7 ± 22.9 dB to 49.2 ± 23.3 dB (p < 0.0001), respectively. The mean air-bone gaps also improved significantly, and were within 10 dB at 250 Hz, 500 Hz and 1 kHz, and 11 dB at 2 kHz. One or more complications occurred in 32 patients (32/216; 14.8 %). The most common complication was formation of an epithelial pearl (16 ears; 6.8 %), followed by severe TM retraction (9 ears; 3.8 %) and otitis media with effusion (6 ears; 2.6 %). There were no serious complications that caused deterioration of the patient's general condition.

CONCLUSION

Our results showed that RT-TMP had high success rates for TMP closure and good hearing improvement and produced no severe complications that could affect general health status. This novel therapy is simple, safe and minimally invasive, and could help improve the quality of life in patients with TMP.

Long-term exposure to high-concentration dexamethasone in the inner ear via intratympanic administration

The first-line treatment for inner ear disorders is usually oral/systemic steroids. Intratympanic steroid therapy is an alternative option; however, it requires multiple office visits owing to the short residence time of steroids in the inner ear (systemic: 24 h, intratympanic: 2-3 h). Therefore, intratympanic injections of higher steroid concentrations could result in longer drug exposure, providing better treatment outcomes. This study aimed to develop a prototype for high-concentration steroids and examine their safety and feasibility in vivo. Using wild-type Institute for Cancer Research mice, high-concentration steroids (50 mg/mL dexamethasone), typical steroid concentrations (3.3 mg/mL dexamethasone), and sterile saline were administrated into the middle ear cavity via tympanic membrane injection. Auditory brainstem response analysis, vestibular function tests, and morphological analyses were performed to examine the safety and utility of High-conc Dex. One month post-injection, the frequency-averaged auditory brainstem response thresholds of high-dose dexamethasone-treated mice were not significantly different from those of low-dose dexamethasone- and saline-treated mice at all tested frequencies. Furthermore, the total points on vestibular function tests were similar between the three groups. Morphologically, no damage to the inner ear/middle ear mucosa was observed in all groups. Two months post-injection, dexamethasone could still be detected in the high-dose dexamethasone group. Altogether, our data successfully demonstrates the feasibility and safety of high-dose dexamethasone for in vivo use in the middle ear and ensure that the drug localizes to the inner ear. Further research is warranted to develop this new treatment strategy and further characterize its effects in vivo.

Application of artificial intelligence using a convolutional neural network for detecting cholesteatoma in endoscopic enhanced images

OBJECTIVE

We examined whether artificial intelligence (AI) used with the novel digital image enhancement system modalities (CLARA+CHROMA, SPECTRA A, and SPECTRA B) could distinguish the cholesteatoma matrix, cholesteatoma debris, and normal middle ear mucosa, and observe the middle ear cavity during middle ear cholesteatoma surgery.

METHODS

A convolutional neural network (CNN) was trained with a set of images chosen by an otologist. To evaluate the diagnostic accuracy of the constructed CNN, an independent test data set of middle ear images was collected from 14 consecutive patients with 26 cholesteatoma matrix lesions, who underwent transcanal endoscopic ear surgery at a single hospital from August 2018 to September 2019. The final test data set included 58 total images, with 1‒5 images from each modality for each case.

RESULTS

The CNN required only 10 s to analyze more than 58 test images. Using SPECTRA A and SPECTRA B, the CNN correctly diagnosed 15 and 15 of 26 cholesteatoma matrix lesions, with a sensitivity of 34.6% and 42.3%, and with a specificity of 81.3% and 87.5%, respectively.

CONCLUSION

Our preliminary study revealed that AI and novel imaging modalities are potentially useful tools for identifying and visualizing the cholesteatoma matrix during endoscopic ear surgery. The diagnostic ability of the CNN is not yet appropriate for implementation in daily clinical practice, based on our study findings. However, in the future, these techniques and AI tools could help to reduce the burden on surgeons and will facilitate telemedicine in remote and rural areas, as well as in developing countries where the number of surgeons is limited.

Multicenter phase III trial of regenerative treatment for chronic tympanic membrane perforation

OBJECTIVE

To evaluate the efficacy and safety of regenerative treatment for tympanic membrane perforation (TMP) using gelatin sponge, basic fibroblast growth factor (bFGF), and fibrin glue.

METHODS

This was a multicenter, non-randomized, single-arm study conducted at tertiary referral centers. Twenty patients with chronic TMP (age 23-78 years, 6 males, 14 females) were registered from three institutions. All treated patients were included in the safety analysis population. The edges of the TMP were disrupted mechanically by myringotomy and several pieces of gelatin sponge immersed in bFGF were placed and fixed with fibrin glue to cover the perforation. The TMP was examined 4 ± 1 weeks later. The protocol was repeated up to four times until closure was complete. The main outcome measures were closure or a decrease in size of the TMP, hearing improvement, and air-bone gap evaluated 16 weeks after the final regenerative procedure (FRP). Adverse events (AEs) were monitored throughout the study.

RESULTS

Total closure of the TMP at 16 weeks was achieved in 15 out of 20 patients (75.0%, 95% confidence interval [CI]: 50.9%-91.3%) and the mean decrease in size was 92.2% (95%CI: 82.9%-100.0%). The ratio of hearing improvement and the air-bone gap at 16 weeks after FRP were 100% (20/20; 95%CI: 83.2%-100%) and 5.3 ± 4.2 dB (p <0.0001), respectively. Thirteen out of 20 patients (65.0%) experienced at least one AE, but no serious AEs occurred.

CONCLUSION

The results indicate that the current regenerative treatment for TMP using gelatin sponge, bFGF, and fibrin glue is safe and effective.

Characterization of aged rat vocal fold fibroblasts

OBJECTIVES/HYPOTHESIS

To elucidate the aging physiology of the vocal folds, we examined the characters of aged vocal fold fibroblasts (VFFs) in various conditions.

STUDY DESIGN

In vitro study.

METHODS

VFFs from young (12-week-old) and aged (19-month-old) Sprague-Dawley rats were compared. Proliferative capacity, ratio of myofibroblast to fibroblast, myofibroblast function, and extracellular matrix production were examined in the following conditions: naïve, basic fibroblast growth factor (bFGF) supplemented, and hepatocyte growth factor (HGF) supplemented.

RESULTS

Aged VFFs demonstrated reduced proliferation by cell counting, though the ratio of Ki-67-positive cells showed no difference. Aged VFFs exhibited an increased expression of α-smooth muscle actin (α-SMA); however, they demonstrated no enhanced contractile ability in a gel contraction assay. Type I collagen protein was increased age dependently, accompanied with decreased Mmp1 and unchanged Col1a1 transcription. Type I collagen protein and α-SMA represented quite similar reduction patterns to bFGF or HGF administration.

CONCLUSIONS

The following possible characteristics of aged VFFs were implied: long duration of mitosis, increased myofibroblast population size with certain dysfunctions, reduced type I collagen turnover, and correlation between α-SMA expression and type I collagen metabolism. Further investigations of these features will help to clarify presbyphonia's pathology and establish treatment strategies.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:E94-E101, 2019.

A phase I/II exploratory clinical trial for intracordal injection of recombinant hepatocyte growth factor for vocal fold scar and sulcus

Vocal fold scar and sulcus are intractable diseases with no effective established treatments. Hepatocyte growth factor (HGF) has preclinically proven to have potent antifibrotic and regenerative effects on vocal fold scar. The current Phase I/II clinical trial aims to examine the safety and effectiveness of intracordal injection of a recombinant human HGF drug for patients with vocal fold scar or sulcus. This is an open-label, dose-escalating, first-in-human clinical trial. Eighteen patients with bilateral vocal fold scar or sulcus were enrolled and divided into three groups: Step I received 1 μg of HGF per vocal fold; Step II received 3 μg of HGF; and Step III received 10 μg of HGF. Injections were administered once weekly for 4 weeks. The protocol treatment was performed starting with Step I and escalating to Step III. Patients were followed for 6 months post-treatment. Local and systemic safety aspects were examined as primary endpoints, and therapeutic effects were assessed as secondary endpoints using voice handicap index-10; maximum phonation time; vocal fold vibratory amplitude; grade, rough, breathy, asthenic, strained scale; and jitter. The results indicated no serious drug-related adverse events in either the systemic or local examinations. In whole-subject analysis, voice handicap index-10, vocal fold vibratory amplitude, and grade, rough, breathy, asthenic, strained scale were significantly improved at 6 months, whereas maximum phonation time and jitter varied. There were no significant differences in phonatory data between the step groups. In conclusion, intracordal injection of a recombinant human HGF drug was safe, feasible, and potentially effective for human patients with vocal fold scar or sulcus.

Atelocollagen Sponge as a Stem Cell Implantation Scaffold for the Treatment of Scarred Vocal Folds

Objectives

Treatment of vocal fold scarring remains a therapeutic challenge. Our group previously reported the efficacy of treating injured vocal folds by implantation of bone marrow–derived stromal cells containing mesenchymal stem cells. Appropriate scaffolding is necessary for the stem cell implant to achieve optimal results. Terudermis is an atelocollagen sponge derived from calf dermis. It has large pores that permit cellular entry and is degraded in vivo. These characteristics suggest that this material may be a good candidate for use as scaffolding for implantation of cells. The present in vitro study investigated the feasibility of using Terudermis as such a scaffold.

Methods

Bone marrow–derived stromal cells were obtained from GFP (green fluorescent protein) mouse femurs. The cells were seeded into Terudermis and incubated for 5 days. Their survival, proliferation, and expression of extracellular matrix were examined.

Results

Bone marrow–derived stromal cells adhered to Terudermis and underwent significant proliferation. Immunohistochemical examination demonstrated that adherent cells were positive for expression of vimentin, desmin, fibronectin, and fsp1 and negative for beta III tubulin. These findings indicate that these cells were mesodermal cells and attached to the atelocollagen fibers biologically.

Conclusions

The data suggest that Terudermis may have potential as stem cell implantation scaffolding for the treatment of scarred vocal folds.

Glottic regeneration with a tissue-engineering technique, using acellular extracellular matrix scaffold in a canine model

Acellular extracellular matrix scaffold derived from porcine urinary bladder (UBM) is decellularized material that has shown success for constructive remodelling of various tissues and organs. The regenerative effects of UBM were reported for the tympanic membrane, oesophagus, trachea, larynx, pleura and pericardium in animal studies, with promising results. The aim of this study was to investigate the regenerative effects of UBM on hemilarynx, using a canine model. A left partial hemilaryngectomy was performed and the surgical defects were reconstructed by insertion of UBM scaffold. Although local infection was observed in one dog in 1 week after implantation of the scaffold, all dogs showed good re-epithelialization with minimum complication in 1 month. The effect of regeneration of the larynx was evaluated 6 months after the operation. The excised larynx experiments were performed to measure phonation threshold pressure (PTP), normalized mucosal wave amplitude (NMWA) and normalized glottal gap (NGG). The results of the measurements showed that PTP was normal or near normal in two cases and NMWA was within normal range in three cases, although there were individual variations. Histological examination was completed to evaluate structural changes in the scaffold with the appearance of the new cartilaginous structure. However, the regenerated vocal fold mucosa was mostly scarred. The UBM scaffold has shown to be biocompatible, biodegradable and useful for tissue regeneration of the hemilarynx, with possible restoration of function of the vocal fold. The vocal fold mucosa was scarred, which is the next challenge to be addressed. Copyright © 2014 John Wiley & Sons, Ltd.

Drug Delivery System of Hepatocyte Growth Factor for the Treatment of Vocal Fold Scarring in a Canine Model

Objectives:

Vocal fold scarring remains a therapeutic challenge. Previous studies have indicated that hepatocyte growth factor (HGF), a strong antifibrotic element, has therapeutic potential for restoring scarred vocal folds. To enhance the effect of HGF in vivo, we developed a novel drug delivery system (DDS) in which HGF is embedded in gelatin hydrogel and continuously released over a period of 2 weeks. In the present study we investigated the therapeutic efficacy of the HGF DDS on vocal fold scarring by using a canine model.

Methods:

The vocal folds of 8 beagles were unilaterally scarred by stripping the entire layer of the lamina propria. The contralateral vocal folds were kept intact as normal controls. One month after the procedure, hydrogels (0.5 mL) containing 1 μg of HGF were injected into the scarred vocal folds of 4 dogs (HGF-treated group), whereas hydrogels containing saline solution were injected in the other 4 dogs (sham group). Histologic and vibratory examinations were completed for each group 6 months after the initial surgery.

Results:

The excised larynx experiments showed significantly better vibration in terms of mucosal wave amplitude and glottal closure in the HGF-treated group compared to the sham group. Histologic evaluation of the vocal folds indicated remarkable reduction in collagen deposition and tissue contraction, with favorable restoration of hyaluronic acid and elastin in the HGF-treated group.

Conclusions:

The present findings suggest that the novel HGF DDS may provide favorable effects in restoring the vibratory properties of scarred vocal folds.

A Perforating Artery Compressing the Nerve Rootlet and Causing Glossopharyngeal Neuralgia

BACKGROUND

A surgical procedure for glossopharyngeal neuralgia (GPN) was selected from microvascular decompression, glossopharyngeal and upper vagal rhizotomy, or a combination of these procedures based on the presence of arteries compressing the glossopharyngeal and vagal rootlets. The offending artery is usually a main trunk or branch of the cerebellar arteries. A perforating artery is a known but uncommon variation of the offending artery that causes GPN. The appropriate procedure for such cases is unknown.

OBJECTIVE

To analyze the clinical significance of the perforating artery in GPN, we describe 2 patients with a perforating artery compressing the rootlet, and its mobilization relieved neuralgia. We examined the validity of decompressing a perforating artery as an alternative to rhizotomy in such cases.

METHODS

We independently reviewed 12 GPN patients treated with microvascular decompression. The patients' pain severity, medication doses, preoperative imaging studies, intraoperative findings, and outcomes were examined.

RESULTS

Eleven patients had neurovascular compression of the glossopharyngeal nerve. In 2 of the patients, a perforating artery compressed the rootlet, thereby generating an indentation and creating a discoloration of the rootlet. Mobilizing the perforating artery with no additional rhizotomy provided complete pain relief with no significant complications and allowed the discontinuation of medications.

CONCLUSION

Even a small perforating artery can cause GPN when it compresses the rootlet. In such cases, mobilization of the perforating artery with no additional rhizotomy is an effective surgical option.

Comparison of ASCs and BMSCs combined with atelocollagen for vocal fold scar regeneration

OBJECTIVES/HYPOTHESIS

Vocal fold scar remains a therapeutic challenge. Mesenchymal stromal cells (MSCs) are promising tools for regenerative medicine. Nevertheless, few in vivo studies have directly compared various sources of MSCs. The aim of this study was to investigate the therapeutic potential of adipose-derived stromal cells (ASCs) in comparison with bone marrow-derived stromal cells (BMSCs) for vocal fold regeneration.

STUDY DESIGN

Prospective animal experiments with controls.

METHODS

Two months after stripping of the lamina propria, 18 beagles were divided into four implantation groups: atelocollagen alone (collagen group), atelocollagen with BMSCs (BMSC-collagen), atelocollagen with ASCs (ASC-collagen), or a sham-treated group. One or 6 months after implantation, vibratory and histological examinations were performed.

RESULTS

Mucosal vibration was significantly improved in both of the MSC-implanted groups compared with the sham-treated group, whereas only the ASC-collagen group showed a significantly smaller glottal gap than the collagen group. Moreover, in the ASC-collagen group, a significant reduction of collagen density was observed compared to the sham-treated group, and there was a trend for better restoration of hyaluronic acid (HA). Implanted MSCs were detected 1 month postimplantation; however, none survived 6 months postimplantation.

CONCLUSIONS

Although implantation of an atelocollagen sponge and ASCs into vocal fold scars induced vibratory recovery comparable to that of BMSCs, ASCs might have more potential in terms of restoration of HA and suppression of excessive collagen deposition.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:1143-1150, 2016.

Biocompatibility and efficacy of collagen/gelatin sponge scaffold with sustained release of basic fibroblast growth factor on vocal fold fibroblasts in 3-dimensional culture

OBJECTIVE

Treatment of vocal fold scarring remains challenging. We have previously reported the therapeutic effects of local injection of basic fibroblast growth factor (bFGF) in animal models and humans. A novel collagen/gelatin sponge (CGS) is capable of sustained release of bFGF, which compensates for its quick absorption in vivo, avoiding multiple injections. This study aimed to evaluate the biocompatibility and efficacy of the CGS in rat vocal fold fibroblasts prior to human trials.

METHODS

Fibroblasts extracted from Sprague-Dawley rat vocal folds were seeded onto a CGS and then cultivated with bFGF at concentrations of 0, 10, and 100 ng/mL. Vocal fold fibroblast morphology, adhesion, proliferation, and gene expression were measured under these 3-dimensional conditions.

RESULTS

Cells adhered to the CGS from day 1. Although no significant differences in cell morphology were detected, cell proliferation was accelerated by bFGF administration. Expression of endogenous bFGF and hepatocyte growth factor was significantly up-regulated at 10 ng/mL bFGF. The expression of procollagen I and procollagen III was significantly suppressed, whereas HAS-1 and HAS-2 were up-regulated at 10 and 100 ng/mL bFGF.

CONCLUSION

The collagen/gelatin sponge is biocompatible with vocal fold fibroblasts and may be useful as a bFGF drug delivery system for the treatment of scarred vocal folds.

Effect of AST on age-associated changes of vocal folds in a rat model

OBJECTIVES/HYPOTHESIS

Reactive oxygen species (ROS) are associated with aging. Astaxanthin (AST) is a strong antioxidant and has been reported to prevent various ROS-induced diseases. In the current study, we investigated the effect of AST on age-associated histological and mRNA changes of vocal folds.

STUDY DESIGN

Prospective animal experiment with control.

METHODS

Six-month-old Sprague-Dawley rats were fed on a normal powder diet with 0.01% (w/w) AST (aged AST-treated group) or without AST (aged sham-treated group). After 12 months of feeding, the larynges were harvested for histology, immunohistochemical detection of 4-hydroxy-2-nonenal (4-HNE), and quantitative real-time polymerase chain reaction for basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF). Thirteen-week-old rats were used as a young control group (young group).

RESULTS

The expression of 4-HNE, an oxidative stress marker, significantly increased in the two aged groups compared with the young group. Histological examination showed that the deposition of hyaluronic acid in the lamina propria (LP) was significantly reduced in the aged sham-treated group compared with the young group, but no significant difference was observed between the aged AST-treated group and the young group. There were no significant differences in the mRNA expression of bFGF and HGF between the aged AST-treated group and the young group, although the expression of these genes was significantly reduced in the aged sham-treated group as compared with the young group.

CONCLUSIONS

These results suggest that AST has the potential to attenuate age-associated changes of vocal folds.

Regenerative phonosurgical treatments for vocal fold scar and sulcus with basic fibroblast growth factor

OBJECTIVES/HYPOTHESIS

Vocal fold scar and sulcus are still challenges. Basic fibroblast growth factor (bFGF) has proven to be effective to resolve scar tissue in animal models. This study reports the efficacy of regenerative treatments using bFGF on vocal fold scar and sulcus in human cases.

STUDY DESIGN

Retrospective chart review.

METHODS

Fifteen cases (7 scar; 8 sulcus) were treated by either local injection of bFGF (n = 6) or regenerative surgery using bFGF (n = 9). Injection regimen was to locally apply 10 micrograms of bFGF in 0.5 mL saline into each vocal fold under topical anesthesia repeatedly (4 times with intervals of 1 week between each injection). The regenerative surgical procedure consisted of the dissection of scar tissue and the implant of gelatin sponge with bFGF. Follow-up periods ranged from 6 months to 24 months.

RESULTS

Maximum Phonation Time (MPT); Voice Handicap Index (VHI)-10; and Grade, Roughness, Breathiness, Asthenia, Strain (GRBAS) scale were assessed in both groups. The injection group showed significant improvement on VHI-10 and GRBAS. The regenerative surgery group showed significant improvement in all parameters. Jitter and shimmer were evaluated in the surgery group, and the results indicated improvement in six and five cases of nine cases, respectively. No major adverse effects were observed in both treatment groups.

CONCLUSIONS

Regenerative treatments using bFGF has shown to be effective for improvement of vocal function in scar and sulcus.

Expression of Reactive Oxygen Species during Wound Healing of Vocal Folds in a Rat Model

Objectives:

Previous studies have indicated that although normal wound healing requires low levels of reactive oxygen species (ROS), excessive amounts of ROS impair wound healing. In injured vocal folds, this excess may result in dysphonia due to scarring that is difficult to treat. However, the expression of ROS during vocal fold wound healing has yet to be investigated. In this study, we assessed the expression and localization of ROS in injured vocal folds by immunohistochemical analysis.

Methods:

Vocal folds of Sprague-Dawley rats were unilaterally injured by stripping the mucosa under transoral endoscopy. The larynges were harvested at specific time points after injury and were immunohistochemically examined for 4-hydroxy-2-nonenal (4-HNE), an ROS marker, and for the presence of inflammatory cells.

Results:

We found that 4-HNE–immunopositive cells were significantly increased in the lamina propria of the injured vocal folds as compared to the normal vocal folds on postinjury days 1 and 3. More than half of the 4-HNE–immunopositive cells were also immunopositive for a macrophage- and granulocyte-specific antibody.

Conclusions:

This study suggests that a large amount of ROS is produced during early-phase wound healing, until postinjury day 3, and that this period may be crucial for regulating ROS levels. The results also suggest that inflammatory cells may contribute to ROS generation.

The protective efficacy of basic fibroblast growth factor in radiation-induced salivary gland dysfunction in mice

OBJECTIVES/HYPOTHESIS

Radiotherapy is one of the most effective treatments for head and neck cancer. However, in addition to the target tumor, normal salivary glands are also included in the irradiation field. This unavoidably results in dry mouth syndrome as a side effect. In this study, the protective efficacy of basic fibroblast growth factor (bFGF) was investigated in radiation-damaged salivary glands.

STUDY DESIGN

Prospective animal experiment with control.

METHODS

Nine-week-old female C57BL/6 mice were divided into three groups. All mice in two of the three groups were irradiated (10 Gy) at the same time. In the bFGF-treated group, bFGF was administered to the submandibular glands for 3 consecutive days after neck irradiation. Mice in the untreated control group were administered distilled water. Mice in the third group were not irradiated and did not receive any additional treatments. Saliva flow rate and submandibular gland morphology were assessed, and the apoptotic response of irradiated submandibular glands was also evaluated.

RESULTS

Administration of bFGF improved hyposalivation 8 weeks after irradiation, and histologic analysis revealed that bFGF-treated glands contained more acinar cells compared to untreated glands. The apoptotic response to irradiation, examined 1 and 2 days after irradiation, was reduced, and quantitative real-time polymerase chain reaction revealed a paracrine effect for bFGF in the glands that received bFGF treatment.

CONCLUSIONS

Our study indicates that bFGF prevents salivary gland dysfunction after irradiation. The protective benefits of bFGF may be attributed to the inhibition of radiation-induced apoptosis as well as the paracrine effect it has in these tissues.

Implantation of an atelocollagen sponge with autologous bone marrow-derived mesenchymal stromal cells for treatment of vocal fold scarring in a canine model

OBJECTIVES

Vocal fold scarring remains a therapeutic challenge. A new regenerative approach is needed to restore disorganized extracellular matrix. Tissue regeneration requires appropriate cells and a scaffold. Bone marrow-derived mesenchymal stromal cells (BMSCs) are multipotent and secrete many kinds of growth factors to regenerate tissues. Atelocollagen sponges have many large pores that permit cell entry. The present study was performed to evaluate whether implantation of an atelocollagen sponge plus BMSCs is effective for the treatment of vocal fold scarring.

METHODS

Twelve beagles underwent implantation of an atelocollagen sponge or of an atelocollagen sponge with autologous BMSCs (1.0 x 10(6) cells) in the subepithelial pockets of scarred vocal folds. Six months after the operation, vibratory examinations and histologic examinations were performed.

RESULTS

Mucosal vibrations improved significantly for the atelocollagen sponge-implanted vocal folds. Histologic analyses revealed favorable restoration of the extracellular matrix in the lamina propria. Increased distribution of hyaluronic acid and decreased dense collagen deposition were also noted. These improvements were enhanced by implantation of BMSCs.

CONCLUSIONS

Implantation of atelocollagen sponges with autologous BMSCs into scarred vocal folds significantly increased hyaluronic acid distribution and decreased dense collagen deposition in the lamina propria, leading to better mucosal vibration.

Regeneration of radiation damaged salivary glands with adipose-derived stromal cells

OBJECTIVES

Radiotherapy is one of the most effective treatments for head and neck cancer. However, the development of dry mouth syndrome is an unavoidable side effect because, in addition to the tumor, the normal salivary glands are included in the irradiation field. Previously, we investigated the protective efficacy of basic fibroblast growth factor (bFGF) in radiation-damaged salivary glands. In this study, we investigated the efficacy of adipose-derived stromal cell (ADSC) transplantation for the regeneration of radiation damaged salivary glands.

STUDY DESIGN

Prospective animal experiment with control.

METHODS

ADSCs (500,000 cells isolated from green fluorescent protein mice) were transplanted into submandibular glands of C57BL/6 mice 10 weeks after 10 Gy irradiation (ADSC group). Phosphate-buffered saline was administered to mice as a control (sham group). Submandibular gland morphology and saliva flow rate were assessed just prior to transplantation and at 5 and 10 weeks posttransplantation. Quantitative RT-PCR was performed to examine the response of irradiated submandibular glands to ADSC transplantation.

RESULTS

Saliva flow rate in the ADSC group was improved compared to the sham group. Although acinar cell damage was detected in both groups, the proliferation of blood vessels and other paracrine effects were observed only in the ADSC group. Additionally, the differentiation of ADSCs into blood endothelial cells and ductal cells was also observed.

CONCLUSIONS

Our study indicates that ADSCs have the potential to restore salivary gland function after irradiation. The restoration of blood flow within submandibular gland tissue may explain the beneficial effects of ADSCs.

Prevention of buccal mucosa scarring with transforming growth factor β3

OBJECTIVES/HYPOTHESIS

In the treatment of tumorous diseases, scarring often forms after resection or irradiation. Scarring of the buccal mucosa causes difficulty in opening the mouth and mastication, decreasing quality of life. Transforming growth factor (TGF) β3 is an isoform of TGFβ1 that is known to accelerate scarring, although it has different effects on wound healing. TGFβ3 administration into wounds has been associated with improvement in the quality of healing skin in vivo. TGFβ3 is also considered to be an important anti-scarring factor in buccal mucosa. The present study aimed to examine whether TGFβ3 is effective for prevention and treatment of buccal mucosa scarring.

STUDY DESIGN

Prospective study using an animal model.

METHODS

Thirty Sprague-Dawley rats were involved in this study. We injected 0.5 mL of TGFβ3 (0.005 μg/mL, 0.05 μg/mL, 0.5 μg/mL, 5 μg/mL) or saline was injected into the buccal submucosa. Fifteen minutes after the injection, the mucosa was removed down to the masseter muscle or orbicularis oris muscle layer using a 6-mm biopsy punch. Six weeks after the operation, the buccal mucosae were harvested after euthanasia. Morphologic and histologic examinations were performed.

RESULTS

The administration of 0.5 μg/mL TGFβ3 induced rapid re-epithelialization and suppressed scar formation. In the submucosal layer, favorable restoration of hyaluronic acid and elastin was seen in the TGFβ3-treated groups compared to the saline-treated group.

CONCLUSIONS

TGFβ3 is considered to be effective for better restoration of extracellular matrices of injured buccal mucosa, suggesting a preventative effect of buccal mucosa scarring.

Laryngeal regeneration using tissue engineering techniques in a canine model

OBJECTIVES

We previously reported that polypropylene mesh covered with collagen sponge is a useful material for the regeneration of the trachea and the cricoid cartilage. The aim of this study was to regenerate larynges after partial hemilaryngectomy with this new biomaterial.

METHODS

A left partial hemilaryngectomy was performed on 12 adult beagles. The defect size was about 1.8 x 1.0 cm. Both sides of polypropylene mesh were coated with either 1% or 3% collagen sponge. This scaffold was wrapped in fascia lata harvested from the left thigh and then fixed in place over the defect. Endoscopic examinations were performed periodically. Six months after treatment, 3-dimensional computed tomographic scanning was performed. Vibratory examinations were also performed with excised larynges.

RESULTS

In the 1% collagen group, exposure or dislocation of the mesh was found in 3 of 6 cases, but in the 3% group, no exposure of the mesh was seen. The morphological findings in the vocal fold were better in the 3% group than in the 1% group, but a difference in the vertical levels of the vocal folds was found in both groups.

CONCLUSIONS

This study suggests that 3% collagen-coated polypropylene mesh wrapped with autologous fascia is a useful material for laryngeal regeneration.

An early mastoid cavity epithelialization technique using a postauricular pedicle periosteal flap for canal wall-down tympanomastoidectomy

CONCLUSIONS

Most ears that were treated with a new surgical method were rendered dry and safe, with cavity problems minimized by this simple technique. This technique is also valid in terms of medical economy because it shortens the hospitalization period and subsequent outpatient care is not required frequently.

OBJECTIVES

Canal wall-down tympanomastoidectomy was a well established procedure for severe chronic otitis media, especially cholesteatoma. However, this procedure has some defects, so-called cavity problems, caused by non-epithelialized bony wall. The aim of this study was to evaluate the early epithelialized technique for the surface of widely formed external acoustic meatus after canal wall-down tympanomastoidectomy.

METHODS

Twenty-five patients who had been diagnosed with cholesteatoma were divided into two groups. Group I consisted of 15 patients who underwent a new method in which the open cavity was lined with a pedicle periosteal flap of the postauricular region together with free temporal fascia grafts. As a control, 10 patients in group II underwent the standard operation that uses only free temporal fascia grafts.

RESULTS

A comparison of the two groups showed that it took only 1 month on average for the entire surface of the external auditory meatus of the patients in group I to epithelialize and dry up perfectly, although the same area in all the patients in group II was not dried up perfectly until over 80 days.

A tissue-engineering approach for stenosis of the trachea and/or cricoid

CONCLUSION

This new regenerative therapy shows great potential for the treatment of stenosis of the trachea and/or cricoids (STC).

OBJECTIVES

To estimate the potential of tissue-engineered artificial trachea (AT) for treatment of STC in clinical applications. We previously reported that AT was a useful material for implantation into a tracheal defect after resection of cancer. There are many causes of stenosis of the respiratory tract and STC is particularly difficult to treat.

METHODS

The AT was a spiral stent composed of Marlex mesh made of polypropylene and covered with collagen sponge made from porcine skin. Three patients with STC were treated by this tissue-engineering method. All of them suffered from STC caused by long endotracheal intubations. They underwent a two-stage operation. In the first operation, after resection of the stenotic regions, the edge of the tracheal cartilage was sutured to the edge of the skin. The tracheal lumen was exposed and a T-shaped cannula was inserted into the large tracheostoma. At 3 weeks to 2 months after the first operation, the trachea and skin were separated. The trimmed AT with venous blood and basic fibroblast growth factor (b-FGF) was then implanted into the cartilage defect.

RESULTS

Postoperatively, all patients were able to breathe easily and had no discomfort in their daily activities. Six months after the second operation, we observed enough air space in the trachea and cricoid by computed tomography (CT) imaging and fiber endoscopy.

Atelocollagen Sponge as a Stem Cell Implantation Scaffold for the Treatment of Scarred Vocal Folds

Objectives:

Treatment of vocal fold scarring remains a therapeutic challenge. Our group previously reported the efficacy of treating injured vocal folds by implantation of bone marrow—derived stromal cells containing mesenchymal stem cells. Appropriate scaffolding is necessary for the stem cell implant to achieve optimal results. Terudermis is an atelocollagen sponge derived from calf dermis. It has large pores that permit cellular entry and is degraded in vivo. These characteristics suggest that this material may be a good candidate for use as scaffolding for implantation of cells. The present in vitro study investigated the feasibility of using Terudermis as such a scaffold.

Methods:

Bone marrow—derived stromal cells were obtained from GFP (green fluorescent protein) mouse femurs. The cells were seeded into Terudermis and incubated for 5 days. Their survival, proliferation, and expression of extracellular matrix were examined.

Results:

Bone marrow—derived stromal cells adhered to Terudermis and underwent significant proliferation. Immunohistochemical examination demonstrated that adherent cells were positive for expression of vimentin, desmin, fibronectin, and fsp1 and negative for beta III tubulin. These findings indicate that these cells were mesodermal cells and attached to the atelocollagen fibers biologically.

Conclusions:

The data suggest that Terudermis may have potential as stem cell implantation scaffolding for the treatment of scarred vocal folds.

Temporal changes in vocal functions of human scarred vocal folds after cordectomy

OBJECTIVES/HYPOTHESIS

The maturation process of scarred vocal folds has previously been investigated using animal models. However, in human models the features of scarred vocal folds have rarely been described, and the process by which the scar changes with time is not well known. The present study aimed to investigate the maturation process of human vocal folds scarred by cordectomy in terms of vibratory and aerodynamic functions.

STUDY DESIGN

Prospective case series.

METHODS

Eight patients with early glottic carcinoma and two patients with leukoplakia of the vocal fold underwent endoscopic cordectomy at Kyoto University Hospital between 2006 and 2008. The temporal changes in their vocal functions were evaluated using acoustic and aerodynamic analyses and videostroboscopic examination.

RESULTS

Normalized mucosal wave amplitude, mean flow rate, and the amplitude perturbation quotient appear to stabilize about 6 months after the procedure. Although there were individual variations in the changes in normalized glottal gap and maximum phonation time, it appears to take at least 6 months to reach plateau. The other parameters-pitch perturbation quotient and noise to harmonic ratio-varied by individual, and thus it was difficult to identify commonalities in the healing process.

CONCLUSIONS

Some individual variation was observed in the temporal changes of vocal function of scarred vocal folds after cordectomy. However, in terms of vibratory and aerodynamic functions, this study suggests that it takes at least 6 months for maturation of vocal fold scarring.

In situ tissue engineering of canine skull with guided bone regeneration

CONCLUSION

Calcium alginate (CA) membrane prevents excessive fibrous tissue intrusion and/or dislocation of a bone scaffold. However, CA membrane did not always accelerate cranial bone regeneration.

OBJECTIVE

We previously reported skull regeneration using a bone substitute material (BSM), which consisted of collagen-coated beta-tricalcium phosphate and autologous bone fragments, and bone marrow-derived stromal cells (BSCs). However, excessive fibrous tissue intrusion or dislocation of the BSM occasionally interrupted bone regeneration. To avoid such problems, we examined CA membrane, which is useful for guided bone regeneration (GBR), to investigate whether this material maintains the bone regenerative space.

MATERIALS AND METHODS

Bone defects (2x2 cm) were created in the skulls of 12 adult beagle dogs using the same clinical procedure. Four experimental models were tested with or without BSM plus BSCs or CA membrane. In group I, the original free bone flap was replaced at the defect. In group II, after replacing the bone flap, the defect was covered with CA membrane. In group III, BSM plus BSCs were used as a gap filler. In group IV, BSM plus BSCs and CA membrane were applied. Histological examinations were performed 3 and 6 months after the operation.

RESULTS

In groups I and II, bone regeneration was not observed but fibrous tissue intrusion was prevented in group II. Bone neogenesis was more observed in group III than in group IV at 3 months (p<0.05). At 6 months, the regenerated areas were larger than those observed at 3 months, but the differences between groups III and IV were not statistically significant.

Implantation of an Atelocollagen Sheet for the Treatment of Vocal Fold Scarring and Sulcus Vocalis

Objectives:

The management of vocal fold scarring and sulcus vocalis is challenging. These disorders are thought to be fibroplastic anomalies in the cover portion of the vocal fold that cause deterioration of the vibratory properties of the vocal fold mucosa. Histologic studies have revealed disorganization of extracellular matrix that needs to be addressed in the treatment of scarred vocal folds. Replacement of scar tissues with an appropriate implant may lead to regeneration of the vocal fold mucosa and its tissue properties. This retrospective case study examined the feasibility of using an atelocollagen sheet as a regenerative implant.

Methods:

Six patients with a post-cordectomy scar or sulcus vocalis underwent implantation of an atelocollagen sheet into the lamina propria of the vocal folds. The procedure consisted of elevation of a microflap, dissection and removal of scar tissue, implantation of the material, and wound closure. Vocal function was evaluated before and after surgery by stroboscopic examination and by aerodynamic and acoustic analyses.

Results:

The postoperative changes of aerodynamic and acoustic parameters varied among patients; however, gradual improvement was seen in most cases over a year. Stroboscopic findings also revealed gradual improvement of vibratory properties in most cases.

Conclusions:

Implantation of an atelocollagen sheet may have restorative effects on vocal fold scarring and sulcus vocalis in terms of tissue properties and function of the mucosa.

Regeneration of aged vocal fold: first human case treated with fibroblast growth factor

BACKGROUND/OBJECTIVES

Aged vocal folds are characterized by atrophy of the mucosa, which caused dysphonia and is difficult to treat. We have revealed a therapeutic potential of basic fibroblast growth factor (bFGF) for tissue regeneration of the aged vocal fold. We report here the first human case that has been treated with bFGF.

STUDY DESIGN

Institutional review board-approved clinical human trial.

METHODS

A 63-year-old male with atrophied vocal folds was treated by local injection of 10 mug of bFGF into the left vocal fold under topical anesthesia. The effects of the injection were examined after 1 to 3 months by videostroboscopy, acoustic, and aerodynamic measurements.

RESULTS

The atrophy of the vocal fold was improved at 1 week after the injection, and glottic gap disappeared. Aerodynamic and acoustic parameters also showed remarkable improvement. These positive effects were maintained up to 3 months.

CONCLUSIONS

The first case with aged vocal folds treated with bFGF administration was presented. The results are encouraging, suggesting therapeutic effects of bFGF for atrophied vocal folds in human.

A case report of myasthenia gravis localized to the larynx

This report describes a very rare case of myasthenia gravis (MG) localized to the larynx, with the onset of dyspnea requiring tracheotomy. The vocal cords of this patient were fixed in the paramedian position. Under fiberscopic observation, improvement of laryngeal function was demonstrated after intravenous injection of edrophonium. However, no voice change occurred. The posterior crico-arytenoid muscle has the sole responsibility of abducting the vocal cord; thus, it is concluded that the dyspnea was caused by the selective paralysis of this muscle. We suggest that MG should be considered in cases of vocal cord paralysis of unknown etiology.

Stabilization technique for columella using trimmed autologous temporal fascia in type III and IV tympanoplasty--Muffler method

CONCLUSION

High success rates of recovery of hearing level in type III and IV tympanoplasty could be achieved by this stabilization technique for columella using trimmed autologous temporal fascia.

OBJECTIVE

The aim of this study was to evaluate a new stabilization technique for columella using trimmed autologous temporal fascia in type III and IV tympanoplasty.

PATIENTS AND METHODS

A total of 55 patients (21 male, 34 female, aged 4-85 years) with chronic otitis media (n=16) and cholesteatoma (n=39) underwent tympanoplasty using this new stabilization technique for columella. Thirty-one patients underwent type III tympanoplasty and 24 patients underwent type IV tympanoplasty. Forty-two patients underwent a staged operation and 13 patients underwent a single operation. The observation period was 3.5 years from 6 months after the last operation.

RESULTS

The overall success rates in type III and IV tympanoplasty were 87.1% (27/31) and 83.3% (20/24), respectively. Two of eight patients for whom the procedure was unsuccessful underwent reoperation and they acquired good hearing.

Vertigo as the sole presenting symptom of cerebellopontine angle meningioma

We report a rare case of cerebellopontine angle (CPA) meningioma whose sole symptom was severe vertigo. A 39-year-old woman with right CPA meningioma was referred for surgery. She experienced severe vertigo for 2 years without any other symptoms. Caloric test indicated right canal paresis of 90%. Her audiogram was normal. After surgery, vertigo symptoms disappeared dramatically. The mechanisms of restoration from vertigo are discussed.

Bilateral congenital ossicular chain disruption mimicking otosclerosis

A rare case of bilateral congenital ossicular chain disruption whose history and findings mimicked those of otosclerosis is reported. A 54-year-old male consulted us for slowly progressing hearing loss. Audiogram showed bilateral intermediate mixed hearing loss. The stapedial reflex was negative and the tympanogram was normal A-type. Based on the diagnosis of otosclerosis, stapes surgery was planned for the left side. Surgical findings revealed normal mobility of the stapes and a small disruption at the incudostapedial joint with connection of intact mucosa. The disruption was repaired with auto-bone columella. The patient's hearing improved after surgery. The surgery for the other side was performed successively, and similar ossicular disruption was observed. The mechanisms of findings that misled the preoperative diagnosis are discussed.

Non-organic hearing loss

CONCLUSION

Most non-organic hearing loss (NOHL) patients were young females. The discrepancy between the results of pure tone audiometry and objective auditory testing suggests NOHL. The diagnostic problem is that objective audiometry is not included in routine examinations and we have to suspect NOHL in order to perform further examination. The correct diagnosis can be difficult in patients who present with unilateral sudden hearing loss or who also have moderate to profound organic hearing loss.

OBJECTIVE

Symptoms and results of auditory tests for NOHL patients were reviewed.

PATIENTS AND METHODS

This study comprised 31 patients with NOHL. Age, symptoms, and the results of subjective and objective audiometry were collected.

RESULTS

Twenty-four patients were female and 7 were male. The age at attendance ranged from 7 to 39 years old, with an average age of 16.6 years. Eight patients received steroids before the correct diagnosis was made. Six of them presented with unilateral sudden hearing loss, and the other two patients had accompanying bilateral organic hearing loss.

Cochlear implants in post-lingually deafened patients

CONCLUSION

Post-lingually deafened patients had good speech intelligibility scores with cochlear implantation. The age at the operation, duration of deafness, and the number of electrodes outside the cochlea showed only weak correlation with the postoperative performance, which warrants cochlear implantation in elderly patients and patients with a long history of deafness and leaving dummy electrodes outside the cochlea. Patients with cochlear obstruction showed comparable performance to patients with an open cochlea.

OBJECTIVE

To evaluate the background and performance of post-lingually deafened cochlear implantation recipients.

PATIENTS AND METHODS

Preoperative and intraoperative factors were collected for 109 cochlear implant subjects. Speech intelligibility scores were obtained and the effects of preoperative and intraoperative factors on postoperative performance were evaluated.

RESULTS

The average speech intelligibility score was 85.1% for vowels, 41.1% for consonant-vowel (CV) syllables, and 80.4% for phrases. The correlation coefficient between the age at the operation, the duration of deafness, and the number of electrodes outside the cochlea and the postoperative performance was between 0.03 and -0.27. Patients with cochlear obstruction and patients with open cochlea did not show significant differences in speech intelligibility tests. The onset of deafness (progressive vs sudden) did not have an effect on the speech intelligibility test.

Clinical characteristics of delayed endolymphatic hydrops: long-term results of hearing and efficacy of hyperbaric oxygenation therapy

CONCLUSION

Diuretics significantly improved hearing in patients with contralateral-type DEH, whereas they did not inpatients with ipsilateral-type DEH.

OBJECTIVE

We report a review of 26 cases of DEH treated in recent 6 years.

PATIENTS AND METHODS

The study group comprised 22 contralateral and 4 ipsilateral types of DEH. The efficacy of diuretics on the improvement in hearing was examined quantitatively. The efficacy of hyperbaric oxygenation therapy (HBO) on hearing was examined in six patients.

RESULTS

The general properties of these cases were similar to those reported previously, except for the high proportion of patients with contralateral-type DEH. Diuretics significantly improved the hearing of patients with contralateral-type DEH. In contrast, no significant improvement by diuretics was noted in ipsilateral-type DEH.

Experimental regeneration of canine larynx: a trial with tissue engineering techniques

CONCLUSION

Since this tissue engineering technique is cost-effective and is less invasive to patients, it may replace conventional approaches in laryngeal reconstructive surgeries.

OBJECTIVE

Laryngeal cancer is one of the most prevalent cancers in the head and neck region, and frequently requires surgical resection. Although there are many ways to reconstruct the larynx after resection, donor tissue is usually required. Recently, tissue engineering techniques have become widely accepted in clinical medicine and have already been applied to some organs. This animal experiment was designed to elucidate the efficacy of laryngeal regeneration using tissue engineering technique.

MATERIALS AND METHODS

A bioartificial scaffold was designed from a replica of a canine larynx. A dental cast was used to replicate the intricate inside shape of the larynx. After copying its shape on a polypropylene mesh sheet, this sheet was coated with spongy collagen from porcine skin. A hemilaryngectomy was performed on beagle dogs under general anesthesia. Then the scaffold, preclotted with a mixture of peripheral blood and bone marrow-derived stromal cells, was implanted and fixed. The postoperative status was examined fiberscopically.

RESULTS

On the eighth day after the operation, the surface of the implant was covered with soft tissue. Finally, the implant was completely covered with regenerated mucosa.

Regeneration of the vocal fold using autologous mesenchymal stem cells

The aim of this study was to regenerate the injured vocal fold by means of selective cultured autologous mesenchymal stem cells (MSCs). Eight adult beagle dogs were used for this experiment. Selective incubation of MSCs from bone marrow was done. These MSCs were submitted to 3-dimensional incubation in 1% hydrochloric acid atelocollagen. Three-dimensional incubated MSCs were injected into the left vocal fold, and atelocollagen only was injected into the right vocal fold of the same dog as a control. Four days after injection, the posterior parts of the vocal folds were incised. The regeneration of the vocal fold was estimated by morphological and histologic evaluations. Our results showed that 3-dimensional incubated MSCs were useful in the regeneration of the injured vocal fold. This study shows that damaged tissues such as an injured vocal fold would be able to be regenerated by tissue engineering.

Recurrent laryngeal nerve regeneration by tissue engineering

The recurrent laryngeal nerve (RLN) does not regenerate well after it has been cut, and no current surgical methods achieve functional regeneration. Here, we evaluate the functional regeneration of the RLN after reconstruction using a biodegradable nerve conduit or an autologous nerve graft. The nerve conduit was made of a polyglycolic acid (PGA) tube coated with collagen. A 10-mm gap in the resected nerve was bridged by a PGA tube in 6 adult beagle dogs (group 1) and by an autologous nerve graft in 3 dogs (group 2). Fiberscopic observation revealed functional regeneration of the RLN in 4 of the 6 dogs in group 1. No regeneration of the RLN was observed in any dog in group 2. We also tested for axonal transport, and measured the compound muscle action potential. The RLN can be functionally regenerated with a PGA tube, which may act as a scaffold for the growth of regenerating axons.