Temporalis fascia transplant for vocal fold scar and sulcus vocalis

Development and growth of the temporal fascia: a histological study using human fetuses

The temporal fascia is a double lamina sandwiching a thick fat layer above the zygomatic bony arch. To characterize each lamina, their developmental processes were examined in fetuses. We observed histological sections from 22 half-heads of 10 mid-term fetuses at 14-18 weeks (crown-rump length, 95-150 mm) and 12 near-term fetuses at 26-40 weeks (crown-rump length, 215-334 mm). The superficial lamina of the temporal fascia was not evident at mid-term. Instead, a loose subcutaneous tissue was attached to the thin, deep lamina of the temporal fascia covering the temporalis muscle. At near-term, the deep lamina became thick, while the superficial lamina appeared and exhibited several variations: i) a mono-layered thick membrane (5 specimens); ii) a multi-layered membranous structure (6) and; iii) a cluster of independent thick fasciae each of which were separated by fatty tissues (1). In the second and third patterns, fatty tissue between the two laminae was likely to contain longitudinal fibrous bands in parallel with the deep lamina. Varying proportions of the multi-layered superficial lamina were not attached to the zygomatic arch, but extended below the bony arch. Whether or not lobulation or septation of fatty tissues was evident was not dependent on age. The deep lamina seemed to develop from the temporalis muscle depending on the muscle contraction. In contrast, the superficial lamina developed from subcutaneous collagenous bundles continuous to the cheek. Therein, a difference in development was clearly seen between two categories of the fasciae.

Perceptual, aerodynamic and acoustic outcomes of surgical technique for sulcus vocalis patients: A systematic review and meta analysis

BACKGROUND

Sulcus Vocalis (SV) is a voice disorder characterized by the parallel invagination of the vocal fold epithelium that adheres to the vocal ligament. This condition disrupts the vibratory function, leading to glottal incompetence, hoarseness, and vocal impairment. Despite various proposed surgical techniques, a standardized treatment approach remains elusive.

METHODS

We conducted a comprehensive search across PubMed/Medline, Embase, Web of Science, Scholar, and the Cochrane Library for studies on SV treatment. The inclusion criteria comprised original studies comparing pre- and post-treatment vocal outcomes in SV patients, published in English. We excluded case reports, reviews, studies without continuous data, and patients with vocal scar/atrophy.

RESULTS

Fifteen observational studies were included (361 patients, 53.73 % male, average age 41.64 years). 80 % of these studies employed self-reported outcomes, while 81.25 % analyzed acoustic/aerodynamic data. The follow-up period varied from 4 to 44 months. All techniques significantly improved Voice Handicap Index (VHI) scores (p < 0.001). Dissective and combined techniques exhibited greater reductions in VHI-30/10 (p < 0.001). Maximum Phonation Time (MPT) improved significantly across all techniques (p < 0.001), with dissective techniques demonstrating superior MPT outcomes (p < 0.001). Jitter improved significantly for dissective and injective techniques (p < 0.001), as did Shimmer for all techniques (p < 0.001). Notably, combined techniques displayed the most significant reductions (p < 0.001).

CONCLUSIONS

Surgical treatments significantly improve subjective, aerodynamic, and acoustic outcomes in SV patients. Dissective and combined dissective/injective techniques appear to yield better perceptual and phonatory outcomes compared to injective techniques alone. Further research is necessary to establish the optimal treatment approach for SV.

Platelet-rich plasma in treatment of scar, atrophy, and sulcus: Short- and long-term results

Objective

Platelet-rich plasma (PRP) is rich in growth factors and is easily obtained from blood samples. Long-term data after PRP injection into the larynx should be improved. This study reports the short-term (3 months) and long-term (12 months) voice results after PRP injection.

Materials and Methods

Sixty-three patients with scars (n = 34), sulcus vocalis (n = 17), recalcitrant nodules (n = 5), atrophy (n = 4), or a combination of these (n = 3) were included (158 injections; median follow-up = 12.3 months). Stroboscopy, voice handicap index (VHI-10), and cepstral spectral index of dysphonia (CSID) before and after treatment (3 months) and at 12 months were tabulated.

Results

VHI-10 changed from 19.5 to 14 at 3 months and 21 to 15 in the long term. The CSID scores improved from 31 to 21 in the short term and 31 to 26 in the long term (p < 0.001, paired t-test). Patients reported improved vocal effort and stamina with slight VHI or CSID score changes. Stroboscopy revealed improved closure and mucosal waves. Patients with severe dysphonia were less likely to improve compared to those with mild to moderate dysphonia. Some patients showed short-term improvements and then deteriorated back to baseline CSID over time (p < .05, paired t-test).

Conclusion

Both short- and long-term improvements in voice following PRP injection have been reported. Patients with mild-to-moderate dysphonia had better outcomes. PRP injection is an alternative treatment for patients with mild-to-moderate dysphonia due to vocal fold scarring, sulcus, and atrophy.

Level of evidence

II Prospective case series treatment.

Assessment of Subjective and Objective Voice Analysis According to Types of Sulcus Vocalis

INTRODUCTION

Sulcus vocalis (SV) subtypes are difficult to diagnose. Non-invasive techniques are sometimes not feasible in the diagnosis. The study aims to demonstrate the effectiveness and applicability of objective and subjective voice analysis combined with videolaryngostroboscopic examination (VLS) in the diagnosis of SV types.

MATERIAL AND METHODS

This is a retrospective study that includes patients who presented to Phoniatric outpatient clinic with complaints related to voice and diagnosed with SV on VLS examination between 2017-2020. The SV type was determined based on VLS findings and the patients were categorized into respective groups. Between- and within-group assessment of objective and subjective voice analysis of SV types was conducted.

RESULTS

47 patients were included in the study; Type I, Type II, Type III SV patients were 16, 17, and 14 in number, respectively. Fundamental frequency (F0) and Shimmer (%) values were significantly high in Type II and III SV cases, whereas the Maximum Phonation Time (MPT) was significantly low. GRBAS, Voice Handicap Index -10 (VHI-10), Reflux Symptom Index (RSI) scores were statistically significantly high in pathological SV and Voice Related Quality of Life (V-RQOL) scores were low. A moderate correlation between VHI-10 and V-RQOL and between RSI and V-RQOL was detected.

CONCLUSIONS

Objective and subjective voice analysis in Type II and III SV show a significant difference compared to Type I SV. The use of objective and subjective voice analysis combined with VLS examination can be helpful in the diagnosis of SV types.

Safety of Platelet-Rich Plasma Subepithelial Infusion for Vocal Fold Scar, Sulcus, and Atrophy

OBJECTIVE

To demonstrate the safety profile of platelet-rich plasma (PRP) as an injectable therapeutic for the treatment of vocal fold scarring and atrophy.

METHODS

Preliminary report on a prospective clinical trial of patients with vocal fold scar or atrophy undergoing unilateral vocal fold subepithelial infusion with autologous PRP. Enrolled patients underwent four subepithelial injections spaced 1 month apart. Adverse events were assessed peri and post-injection at each session. Patient-reported outcomes were collected at every visit using the Voice Handicap Index-10 (VHI-10) and Vocal Fatigue Index (VFI) questionnaires.

RESULTS

Twelve patients underwent unilateral vocal fold injection with autologous PRP prepared according to Eclipse PRP® system protocol. Forty-three injections were performed using a peroral or percutaneous approach. An average of 1.57 ± 0.4 cc (range 0.6-2.0 cc) injectate was used. All patients tolerated the procedure without difficulty or peri-procedural complications. The average duration of follow-up was 3.6 ± 1.8 months. No significant inflammatory reactions or adverse events were seen to date. There was statistically significant improvement in patient-reported outcomes at the 3 month follow up (n = 9) follow-up (mean ΔVHI-10 = 10.8, p < 0.001, mean ΔVFI = 18.9, p = 0.01, t test, paired two sample for means, two-tail). All nine patients who completed the series of four injections subjectively (yes/no) reported they were satisfied with the results.

CONCLUSION

This prospective study cohort demonstrated a favorable safety profile, with no adverse events or peri-procedural complications. Subjective improvements in vocal quality and reduction in vocal fatigue need to be clinically correlated with further study.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:647-653, 2023.

Autologous Tragal Perichondrium Graft for Vocal Fold Scar and Sulcus Vocalis

Between 2006 and 2016 in a Tertiary Academic Center, 11 patients underwent phonomicrosurgery with tragal perichondrium graft placement in Reinke's space for the treatment of sulcus (Ford type 2) and vocal fold scar. A total of six patients out of 11 had an additional autologous fat implantation in order to improve the glottic closure. We evaluated the functional outcome using the Spanish validated version of the VHI- 30 before and 6 months after the surgery. We also measured the subjective appreciation of the obtained outcome, a perceptual voice evaluation using GRBAS scale, and changes in videostroboscopy examinations concerning mucosal wave and glottic closure. In the VHI-30 questionnaire, we observed an improvement in all patients (six of which showed an improvement of 50% or more) with statistically significant results (P = 0.003), and no significant differences between sulcus (Ford type 2) and vocal cord scar patients (P = 0.7579). The results obtained from the single question assessing changes in voice quality showed a high improvement in seven patients. According to the GRBAS scale, all cases improved. Concerning the results of the videostroboscopy, two patients obtained very favorable results, eight of them presented a moderate recovery and only one improved slightly. The following complications were identified: two granulomas, a graft extrusion and a tragal infection. The tragal perichondrium used as an autograft in Reinke's space appears to be a safe and satisfactory choice, comparable to other grafts such as temporalis fascia or autologous fat.

Short-Term Voice Improvement after Repeated Office-Based Platelet-Rich Plasma PRP Injection in Patients with Vocal Fold Scar, Sulcus, and Atrophy

INTRODUCTION

Improving the voice of patients with vocal atrophy, scar, and sulcus vocalis remains challenging. Platelet-rich plasma (PRP) is an autologous biological suitable for regenerative medicine. Office-based injections of PRP may serve as a source of improved wound healing.

MATERIALS AND METHODS

Thirty two office based injections of PRP were performed in 14 patients with scar, sulcus, and vocal atrophy (12 scars, 1 sulcus, and 1 atrophy). PRP was prepared using 20 cc blood draw and double centrifugation method. Injection laryngoplasty was performed using trans cervical or indirect trans oral technique (10 trans cervical, 22 trans-oral). Volume of PRP use was 0.5-0.7 cc per side. Injections varied from 1 to 3 injections at monthly intervals. Videostroboscopy, Voice Handicap Index (VHI-10), and an objective analysis of the voice using Cepstral Peak Prominence (Cepstral Spectral Index of Dysphonia) were recorded. An expert rater speech pathologist rated the audio and stroboscopy results.

RESULTS

Median follow-up was 15 months. No patients were made worse. The mean VHI-10 before the injection was 23. VHI-10 after the injection was 12.5 (P < 0.01). The mean Cepstral Spectral Index of Dysphonia score for CAPE-V sentence was 42.5 before the injection and 23.5 (P < 0.01) after the injection. The expert rater thought the post treatment was better (9/14 acoustic, 10/14 stroboscopy). Eleven of the 14 patients thought the intervention was worthwhile to repeat. The other 3 patients thought the improvement was transient.

CONCLUSION

Office PRP injection into the vocal fold of patients with scar, sulcus, and atrophy may result in short term voice improvements. It is a biological worth considering.

Vocal Fold Fat Augmentation for Atrophy, Scarring, and Unilateral Paralysis: Long-term Functional Outcomes

OBJECTIVE

There is a debate regarding the durability of fat implants. Our experience and recent publications suggest fat implantation may deliver a long-lasting improvement. This study aims to present the long-term outcomes for vocal fold fat augmentation using strict harvesting, preparing, and implantation protocols.

STUDY DESIGN

A prospective cohort conducted between 2014 and 2020 (recruitment 2014-2017).

SETTING

An academic tertiary referral center.

SUBJECTS AND METHODS

Twenty-two patients with glottic insufficiency were enrolled: 11 had unilateral vocal fold paralysis (UVFP), and 11 had atrophy or scar. Harvested fat was injected unilaterally or bilaterally into multiple sites. Six of these patients also had simultaneous microlaryngoscopic removal of other benign glottic lesions. Outcome measurements included video stroboscopy; Grade, Roughness, Breathiness, Asthenia, Strain (GRBAS) score; Voice Handicap Index (VHI); and acoustic analysis, performed preoperatively, 3, 12, 24, and 36 months after surgery.

RESULTS

Ten augmentations were unilateral and 12 bilateral. Comparing the preoperative and 36-month postoperative periods, the mean VHI score improved from 73.45 (±22.78) to 44.88 (±28.93), P = .001, and the mean GRBAS decreased from 8.64 (±3.89) to 2.82 (±2.3), P = .001; 24 months postoperatively, the mean fundamental frequency decreased from 163.88 Hz (±41.61) to 150.44 Hz (±41.47), P = .012. Stroboscopic analysis revealed statistically significant improvement in mucosal wave propagation, phase closure, and phase symmetry. Best results were achieved in the UVFP subgroup. Computed tomography scans demonstrated long-term viability of the implanted adipose tissue.

CONCLUSION

Fat is an excellent source of autologous graft. With careful patient selection and proper surgical technique, fat is suitable for long-term correction of glottic insufficiency. Fat augmentation should be considered as a long-lasting or even permanent solution, rather than temporary.

Bilateral medialization thyroplasty in patients with vocal fold atrophy with or without sulcus

Purpose

To evaluate voice outcome after bilateral medialization thyroplasty in patients with non-paralytic glottic insufficiency due to vocal fold atrophy with or without sulcus.

Methods

Retrospective cohort study on 29 patients undergoing bilateral medialization thyroplasty for vocal fold atrophy (14 procedures) or atrophy with sulcus (15 procedures) between October 2012 and November 2017. Voice data were collected and analyzed for the preoperative and the 3- and 12-month postoperative time point according to a standardized protocol, including Voice Handicap Index (VHI)-30 and perceptual, acoustic and aerodynamic parameters. Failure rate was based on number of revisions within 12 months and non-relevant improvement (< 10 points) in VHI-30 at 12 months.

Results

There was a clinically relevant (≥ 15 points) and statistically significant improvement (p < 0.0001) in the VHI-30 (preoperative: 55.8 points; postoperative at 12 months: 30.9 points). Fundamental frequency for male subjects decreased significantly from 175 to 159 Hz (p = 0.0001). The pre- and post-operative grade of dysphonia was significantly lower in patients with atrophy compared to atrophy and sulcus (mean difference 0.70, p = 0.017).

Conclusion

Bilateral medialization thyroplasty is a valid treatment option for patients with atrophy with or without sulcus. Outcomes are comparable to other methods reported in literature. However, there is a great need for larger, prospective studies with long-term follow-up to gain more insight into the comparative voice outcomes for the different forms of surgery for patients with glottic incompetence due to atrophy with or without sulcus.

Regenerative potential of basic fibroblast growth factor contained in biodegradable gelatin hydrogel microspheres applied following vocal fold injury: Early effect on tissue repair in a rabbit model

Introduction

Postoperative dysphonia is mostly caused by vocal fold scarring, and careful management of vocal fold surgery has been reported to reduce the risk of scar formation. However, depending on the vocal fold injury, treatment of postoperative dysphonia can be challenging.

Objective

The goal of the current study was to develop a novel prophylactic regenerative approach for the treatment of injured vocal folds after surgery, using biodegradable gelatin hydrogel microspheres as a drug delivery system for basic fibroblast growth factor.

Methods

Videoendoscopic laryngeal surgery was performed to create vocal fold injury in 14 rabbits. Immediately following this procedure, biodegradable gelatin hydrogel microspheres with basic fibroblast growth factor were injected in the vocal fold. Two weeks after injection, larynges were excised for evaluation of vocal fold histology and mucosal movement.

Results

The presence of poor vibratory function was confirmed in the injured vocal folds. Histology and digital image analysis demonstrated that the injured vocal folds injected with gelatin hydrogel microspheres with basic fibroblast growth factor showed less scar formation, compared to the injured vocal folds injected with gelatin hydrogel microspheres only, or those without any injection.

Conclusion

A prophylactic injection of basic fibroblast growth factor -containing biodegradable gelatin hydrogel microspheres demonstrates a regenerative potential for injured vocal folds in a rabbit model.

Pathophysiology of Fibrosis in the Vocal Fold: Current Research, Future Treatment Strategies, and Obstacles to Restoring Vocal Fold Pliability

Communication by voice depends on symmetrical vibrations within the vocal folds (VFs) and is indispensable for various occupations. VF scarring is one of the main reasons for permanent dysphonia and results from injury to the unique layered structure of the VFs. The increased collagen and decreased hyaluronic acid within VF scars lead to a loss of pliability of the VFs and significantly decreases their capacity to vibrate. As there is currently no definitive treatment for VF scarring, regenerative medicine and tissue engineering have become increasingly important research areas within otolaryngology. Several recent reviews have described the problem of VF scarring and various possible solutions, including tissue engineered cells and tissues, biomaterial implants, stem cells, growth factors, anti-inflammatory cytokines antifibrotic agents. Despite considerable research progress, these technical advances have not been established as routine clinical procedures. This review focuses on emerging techniques for restoring VF pliability using various approaches. We discuss our studies on interactions among adipose-derived stem/stromal cells, antifibrotic agents, and VF fibroblasts using an in vitro model. We also identify some obstacles to advances in research.

Pathological sulcus vocalis: treatment approaches and voice outcomes in 36 patients

PURPOSE

This is a retrospective study to evaluate the results of surgical treatment of patients with pathological sulcus vocalis.

METHODS

Thirty-six patients with pathological sulcus underwent surgery and in 33 cases were performed additional injection laryngoplasty. The pre- and postoperative evaluation of patients included the GRBAS scale, stroboscopic, and objective acoustic voice assessment. The Voice Handicap Index questionnaire (VHI-30) was also used and the scores were obtained from 33 patients.

RESULTS

The stroboscopic evaluation showed significant improvement of amplitude, mucosal wave, and glottal closure after treatment (p < 0.001). The VHI-30 scores decreased considerably indicating improvement due to the treatment for all aspects measured by VHI (p < 0.05, or p < 0.01). In all domains of GRBAS scale, the differences between preoperative and postoperative assessment were statistically significant (p < 0.001). We observed a significant change in Shim and APQ parameters (p < 0.05). Improvement was also observed in the sAPQ parameter, but it was not statistically significant (p = 0.051). For the remaining acoustic parameters, no changes were observed.

CONCLUSIONS

The surgical procedure with supplementary injection laryngoplasty of the vocal folds is a good treatment option for pathological sulcus vocalis. The post-treatment self-assessment indicates the significant improvement in VHI, just as perceptual-acoustic evaluation of voice does. Patients with pathological sulcus frequently present with amplitude disturbances, what explains their significant improvement after treatment.

Structural Fat Grafting to Improve Outcomes of Vocal Folds’ Fat Augmentation: Long-term Results

Objective

Evaluating the long-term outcomes of vocal fold structural fat grafting.

Study Design

Case series with chart review.

Setting

University hospital.

Subjects and Methods

Seventy-nine dysphonic patients (16-82 years; 55 with unilateral laryngeal paralysis and 24 with vocal fold scarring) underwent vocal fold fat injection. Fat was harvested by low-pressure liposuction and then processed by centrifugation. Refined fat aliquots were placed in the vocal fold and paraglottic space in multiple tunnels to enhance graft neovascularization. All patients were followed for 12 months, 15 for 3 years, and 5 for 10 years with videolaryngostroboscopy, maximal phonation time (MPT) measurement, Voice Handicap Index (VHI) questionnaire, and GRBAS (grade, roughness, breathiness, asthenia, strain) perceptual evaluation. Laryngeal computed tomography (CT) and/or magnetic resonance imaging (MRI) studies were performed in 16 patients 3 to 28 months postoperatively; MRI was repeated in 5 cases 12 to 18 months after the first radiological study.

Results

The voice quality of all patients improved after surgery, and long-term stability was confirmed by MPT, GRBAS, and VHI ( P ranging between .004 and <.001). The results achieved 1 year postoperatively remained stable at 3 and 10 years. Videolaryn-gostroboscopy showed improved glottic closure in all patients despite a limited amount of fat resorption. CT and MRI demonstrated survival of the fat grafts in all of the 16 examined cases. Serial MRI scans showed no change in graft size over time.

Conclusions

The reported clinical and radiological data demonstrate that fat is an effective filler for permanent vocal fold augmentation if the refined micro-aliquots are placed in multiple tunnels.

Vibratory function and healing outcomes after small intestinal submucosa biomaterial implantation for chronic vocal fold scar

OBJECTIVES/HYPOTHESIS

Vocal fold scar is a major cause of dysphonia, and optimal treatments do not currently exist. Small intestinal submucosa (SIS) is a biomaterial developed for the treatment of a variety of pathologies. The purpose of this study was to investigate the effects of SIS implantation on tissue remodeling in scarred vocal folds using routine staining, immunohistochemistry, and high-speed videoendoscopy (HSV).

STUDY DESIGN

Prospective, blinded group analysis.

METHODS

Thirteen New Zealand White rabbits underwent a vocal fold scarring procedure followed by microflap elevation with or without SIS implantation. Seven months later, they underwent a phonation procedure with HSV and laryngeal harvest. Alcian blue and elastica van Gieson staining and immunohistochemistry for collagen types I and III were used to evaluate histological healing outcomes. Dynamic functional remodeling of the scarred vocal fold in the presence of SIS implants was evaluated using HSV imaging to capture restoration of vibratory amplitude, amplitude ratio, and left-right phase symmetry.

RESULTS

Density of collagen I was significantly decreased in SIS versus microflap-treated vocal folds. No differences were found between groups for hyaluronic acid, elastin, or collagen type III. Organization of elastin in the subepithelial region appeared to affect amplitude of vibration and the shape of the vocal fold edge.

CONCLUSIONS

SIS implantation into chronic scar reduced the density of collagen I deposits. There was no evidence of a negative impact or complication from SIS implantation. Regardless of treatment type, organization of elastin in the subepithelial region may be important to vibratory outcomes.

LEVEL OF EVIDENCE

NA. Laryngoscope, 128:901-908, 2018.

Tissue-Engineered Vocal Fold Mucosa Implantation in Rabbits

OBJECTIVE

To assess phonatory function and wound healing of a tissue-engineered vocal fold mucosa (TE-VFM) in rabbits. An "artificial" vocal fold would be valuable for reconstructing refractory scars and resection defects, particularly one that uses readily available autologous cells and scaffold. This work implants a candidate TE-VFM after resecting native epithelium and lamina propria in rabbits.

STUDY DESIGN

Prospective animal study.

SETTING

Research laboratory.

SUBJECTS AND METHODS

Rabbit adipose-derived stem cells were isolated and cultured in three-dimensional fibrin scaffolds to form TE-VFM. Eight rabbits underwent laryngofissure, unilateral European Laryngologic Society type 2 cordectomy, and immediate reconstruction with TE-VFM. After 4 weeks, larynges were excised, phonated, and examined by histology.

RESULTS

Uniform TE-VFM implants were created, with rabbit mesenchymal cells populated throughout fibrin hydrogels. Rabbits recovered uneventfully after implantation. Phonation was achieved in all, with mucosal waves evident at the implant site. Histology after 4 weeks showed resorbed fibrin matrix, continuous epithelium, and mildly increased collagen relative to contralateral unoperated vocal folds. Elastic fiber appearance was highly variable. Inflammatory cell infiltrate was limited to animals receiving sex-mismatched implants.

CONCLUSION

TE-VFMs were successfully implanted into 8 rabbits, with minor evidence of scar formation and immune reaction. Vibration was preserved 4 weeks after resecting and reconstructing the complete vocal fold cover layer. Further studies will investigate the mechanism and durability of improvement. TE-VFM with autologous cells is a promising new approach for vocal fold reconstruction.

Small Intestinal Submucosa Implantation for the Possible Treatment of Vocal Fold Scar, Sulcus, and Superficial Lamina Propria Atrophy

Objectives:

Evaluate the histologic effects of grafting porcine-derived small intestinal submucosa (SIS) into the vocal fold superficial lamina propria (SLP) layer for the potential treatment of vocal fold scar, sulcus and superficial lamina propria atrophy.

Methods:

Small intestinal submucosa was implanted into the right vocal fold SLP of 6 mongrel dogs. The left vocal fold served as a sham surgical control. At 2, 4, and 6 weeks postoperative, bilateral vocal fold specimens were evaluated histologically.

Results:

At 2 and 4 weeks, respectively, SIS-implanted vocal folds demonstrated moderate and mild inflammation and acute and chronic inflammation. At 6 weeks, inflammation was minimal and chronic. The 6-week specimens showed copious amounts of newly generated hyaluronic acid (HA) within the graft. There was no reactive fibrosis at 6 weeks.

Conclusions:

In the canine model, SIS appears safe for SLP grafting. Inflammation is similar to that of sham surgery. Small intestinal submucosa results in newly generated HA without concomitant fibrosis. Small intestinal submucosa has potential to be used in treatment of disorders with SLP, including vocal fold scar, sulcus, and atrophy. Studies evaluating the effect of SIS implantation on vocal fold function, as well as the ultimate fate of the graft, are required.