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Treatment of vocal fold scar with an auto-crosslinked polysaccharide hyaluronan-based gel
Research Forum—Tuesday
10:32 AM Vocal Fold Mobility Following Anterior Cervical Disk Surgery: A Randomized Prospective Study Gregory James Artz, MD (presenter); William M Keane, MD Philadelphia PA; Philadelphia PA
Problem: The true incidence of vocal fold dysfunction following anterior cervical disk fusion (ACDF) is unknown, with few studies documenting laryngeal examination before and after surgery. Consequently, the effect of potential interventions such as limiting endotracheal tube cuff pressure and its effect on this incidence cannot be properly assessed. Methods: This study was a randomized, prospective clinical trial performed at an academic institution. Over a 4-year time period, patients undergoing primary ACDF surgery volunteered to participate. Preoperative and postoperative laryngeal endoscopy was performed. Recorded examinations were reviewed by independent laryngologists for determination of vocal fold mobility. Patients were randomized intraoperatively into 2 groups: a control group and an intervention group. Patients in the intervention group had endotracheal tube cuff pressures maintained below 20 mmHg throughout the surgical procedure. Results: One hundred patients were studied and randomized into 2 groups of 50 patients each. In the acute postoperative period, vocal cord paresis was seen in 8% and paralysis in 4% of studied patients. There was no significant difference in paresis or paralysis rates of the vocal fold on the side of surgery between the control and intervention groups. Conclusion: Vocal cord dysfunction is a common complication of ACDF surgery that can result in significant patient morbidity. Manipulating endotracheal tube cuff pressures did not decrease the risk of intraoperative recurrent laryngeal nerve injuries. Significance: This study demonstrates the true incidence of vocal fold dysfunction after ACDF surgery and that this incidence is unaltered by intraoperative interventions such as reducing endotracheal tube cuff pressures. Support: None reported.
short-term viscoelastic properties after the injection of hyaluronan in scarred rabbit vocal folds. Methods: Vocal folds of New Zealand rabbits were scarred and after 2 months one group received injections with crosslinked hyaluronan and another group was injected with saline. After 2 more months (4 months after scarring) both groups and a third group of control animals with normal vocal folds were euthanized. The larynges were dissected out, 16 vocal folds were frozen in -20 C for viscoelastic measurements, whereas 16 vocal folds were prepared and stained for histological analysis including measurements from digitized slides. Two methods were used for the viscoelastic analysis: (1) analyses were made on intact vocal folds with a linear skin rheometer (LSR) adapted to laryngeal measurements, and (2) the vocal folds were dissected and analyzed in a parallel-plate rheometer. Results: Measurements on the digitized slides showed a thickened lamina propria of the scarred samples as compared to the normal vocal folds (P ⬍ 0.05). The viscoelastic LSR analysis on intact vocal folds showed a tendency to stiffening of the scarred vocal folds as compared to the normal group (P ⫽ 0.05). The parallel plate rheometry on the same samples after dissection showed a decreased dynamic viscocity of the scarred samples injected with hyaluronan (Hylaform) as compared to the normals and to the scarred group that received no hyaluronan (P ⬍ 0.01 and P ⬍ 0.05, respectively). Conclusion: Injection of scarred rabbit vocal folds with hyaluronan in the short term rendered improved viscoelastic parameters. Significance: Hyaluroan may prove useful for treating vocal fold scarring. Support: None reported. 10:48 AM Treatment of Vocal Fold Scar with an AutoCrosslinked Polysaccharide Hyaluronan-Based Gel Bernard Rousseau, MA (presenter); Ichiro Tateya, MD PhD; Jin-Ho Sohn, MD PhD; Nathan V Welham, MSLT; Charles N Ford, MD; Diane M Bless, PhD Madison WI; Madison WI; Madison WI; Madison WI; Madison WI; Madison WI
10:40 AM Viscoelasticity in Scarred Rabbit Vocal Folds after Hyaluronan Injection Stellan Hertegard, MD PhD (presenter); Ake R Dahlqvist, MD PhD; Eric Goodyer, MSc; Frans Maurer, PhD Stockholm Sweden; Umea Sweden; Leicester United Kingdom; Lund Sweden
Problem: Hyaluronan has been shown to improve the viscoelastic properties after injections in normal rabbit vocal folds and in patients with unilateral paresis and vocal fold atrophy. Viscoelasticity is important to the vocal fold vibratory capacity. The aim of the study was to analyze the
Problem: To examine the effectiveness of an autocrosslinked polysaccharide (ACP) hyaluronan-based gel for the treatment of acute vocal fold scar in a canine animal model. Methods: Twelve canine larynges were injured by unilateral stripping of the vocal fold mucosa, from the epithelium down to the thyroarytenoid muscle. Six of these animals were treated with a transcutaneous injection of ACP gel (30 mg) into the thyroarytenoid muscle and remaining lamina propria at the time of injury, and again at 7 and 14 days postoperatively. The remaining animals were treated with an injection of sodium chloride to serve as sham controls. All animals
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Otolaryngology– Head and Neck Surgery Volume 131 Number 2
were euthanized 2 months following the initial treatment. Excised larynx experiments were completed to obtain phonation threshold pressure (PTP) and vocal economy an acoustic output cost ratio (OCR), followed by histologic analysis for hyaluronan and collagen between the scarred and control vocal fold. Results: Dense, thick bundle collagen was observed on the injured side of sham-treated larynges. Minimal collagen deposition was observed on the injured side of ACP-treated larynges. PTP was lower and OCR was higher in the ACPtreated animals. Conclusion: ACP-treated larynges revealed greater ease of phonation and better vocal economy than sham-treated larynges. Collagen deposition was less dense in ACP-treated larynges. ACP gel provided sufficient bulk to the scarred vocal fold. Significance: ACP gel may provide a useful bio-injectable substance for improving rheologic tissue and aerodynamic properties for phonation in the scarred larynx. Support: None reported.
and a greater percentage of animals demonstrated new clonal cell formation (72.7%-HA vs 54.5%-control) (P ⫽ 0.659). No differences were seen in connective tissue organization and epithelial closure. Conclusion: These results show that HA significantly decreases inflammation in tracheal wounds in a rabbit model. Although not statistically significant, the results also suggest that HA may be chondroprotective, as demonstrated in articular cartilage models. Significance: Poor wound healing including cartilage ring damage can contribute to airway compromise especially in an infant after tracheal surgery. This experiment suggests that HA may be useful as an adjunct in improving postoperative tracheal repair. Support: (1) The Friedberg Research Fund in the Department of Otolaryngology at Rush University Medical Center. (2) SEPRAPACK ™ and Hemaseel ™ were both donated by GYRUS ENT and HAEMACURE, respectively under no obligation by the authors.
10:56 AM
11:12 AM
The Effect of Hyaluronic Acid on Tracheal Wound Healing
Use of Bipolar Diathermy in Tonsillectomy Is a Powerful Risk Factor for Hemorrhage
Phillip Samuel LoSavio, MD (presenter); David L Walner, MD; James M Williams, PhD; Kelly A Kaiser; Victoria Mark; David D Caldarelli, MD Chicago IL; Highland Park IL; Chicago IL; Chicago IL; Chicago IL; Chicago IL
David A. Lowe, FRCSEd FRCS (presenter) London United Kingdom
Problem: Various methods have been studied to improve tracheal healing after surgery. Previous experiments have demonstrated the benefits of hyaluronic acid (HA) not only in wound healing in the tympanic membrane, skin, and articular cartilage but also in decreasing adhesions in abdominal operations. The goal of this project was to study the effects of hyaluronic acid on tracheal wound healing. Methods: Twenty-two New Zealand white rabbits, (11 experimental, 11 control) had a 2 mm round defect created in the third tracheal ring. The experimental group had an 8 mm round sodium hyaluronate-based sponge (SEPRAPACK™) fixed over the defect using fibrin glue (Hemaseel™). The control group had a plain 8 mm collagen sponge placed in a similar manner. Tracheal tissue was harvested at 4 weeks postop and histologically scored in regard to inflammation, connective tissue organization, epithelial closure, chondrocyte death, and cartilage regeneration (clonal cell formation) at the area of injury. Statistical analysis was done using the Mann-Whitney U and Fisher-Exact tests. Results: Inflammatory cell infiltration was significantly increased at the area of injury in the control group compared to the HA-treated wound (P ⫽ 0.014). In the HA-treated group a lower percentage of animals had chondrocyte death at the wound edge (45.5%-HA vs 81.8%-control) (P ⫽ 0.183)
Problem: Tonsillectomy remains among the most frequently performed surgical procedures. Bipolar diathermy for tonsillar dissection and/or hemostasis is the most popular technique in the UK. Although it allows good control of intraoperative bleeding, little evidence exists to support diathermy as superior to traditional “cold steel” dissection with only packs and ties for hemostasis. Excessive use of diathermy may further influence the occurrence of secondary haemorrhage. Methods: The National Prospective Tonsillectomy Audit (NPTA) is collecting data on the occurrence of complications following tonsillectomies performed since July 2003 in England and Northern Ireland. Postoperative hemorrhages and other complications within 28 days of surgery leading to delayed discharge, readmission, or return to theatre are recorded. On 23 February 2004, the Audit included data on 13,554 patients, of whom 11,796 (87%) from 252 different hospitals consented to electronic submission of their tonsillectomy data to the central database. Results: We demonstrated an overall hemorrhage rate following tonsillectomy of 3.3%. 2% of patients had a hemorrhage of sufficient severity to require return to the operating theatre. The relative risk of hemorrhage in the bipolar diathermy dissection and hemostasis group (relative to cold steel group) was 3.1 (95% CI 1.9 5.0; P ⬍ 0.0001). Use of cold steel for dissection but bipolar diathermy for hemostasis carried an intermediate risk of hemorrhage, (relative risk 2.2; 95% CI 1.3 3.7; P ⫽ 0.002). High diathermy power settings
TUESDAY
Research Forum—Tuesday P127
10:32 AM Vocal Fold Mobility Following Anterior Cervical Disk Surgery: A Randomized Prospective Study Gregory James Artz, MD (presenter); William M Keane, MD Philadelphia PA; Philadelphia PA
Problem: The true incidence of vocal fold dysfunction following anterior cervical disk fusion (ACDF) is unknown, with few studies documenting laryngeal examination before and after surgery. Consequently, the effect of potential interventions such as limiting endotracheal tube cuff pressure and its effect on this incidence cannot be properly assessed. Methods: This study was a randomized, prospective clinical trial performed at an academic institution. Over a 4-year time period, patients undergoing primary ACDF surgery volunteered to participate. Preoperative and postoperative laryngeal endoscopy was performed. Recorded examinations were reviewed by independent laryngologists for determination of vocal fold mobility. Patients were randomized intraoperatively into 2 groups: a control group and an intervention group. Patients in the intervention group had endotracheal tube cuff pressures maintained below 20 mmHg throughout the surgical procedure. Results: One hundred patients were studied and randomized into 2 groups of 50 patients each. In the acute postoperative period, vocal cord paresis was seen in 8% and paralysis in 4% of studied patients. There was no significant difference in paresis or paralysis rates of the vocal fold on the side of surgery between the control and intervention groups. Conclusion: Vocal cord dysfunction is a common complication of ACDF surgery that can result in significant patient morbidity. Manipulating endotracheal tube cuff pressures did not decrease the risk of intraoperative recurrent laryngeal nerve injuries. Significance: This study demonstrates the true incidence of vocal fold dysfunction after ACDF surgery and that this incidence is unaltered by intraoperative interventions such as reducing endotracheal tube cuff pressures. Support: None reported.
short-term viscoelastic properties after the injection of hyaluronan in scarred rabbit vocal folds. Methods: Vocal folds of New Zealand rabbits were scarred and after 2 months one group received injections with crosslinked hyaluronan and another group was injected with saline. After 2 more months (4 months after scarring) both groups and a third group of control animals with normal vocal folds were euthanized. The larynges were dissected out, 16 vocal folds were frozen in -20 C for viscoelastic measurements, whereas 16 vocal folds were prepared and stained for histological analysis including measurements from digitized slides. Two methods were used for the viscoelastic analysis: (1) analyses were made on intact vocal folds with a linear skin rheometer (LSR) adapted to laryngeal measurements, and (2) the vocal folds were dissected and analyzed in a parallel-plate rheometer. Results: Measurements on the digitized slides showed a thickened lamina propria of the scarred samples as compared to the normal vocal folds (P ⬍ 0.05). The viscoelastic LSR analysis on intact vocal folds showed a tendency to stiffening of the scarred vocal folds as compared to the normal group (P ⫽ 0.05). The parallel plate rheometry on the same samples after dissection showed a decreased dynamic viscocity of the scarred samples injected with hyaluronan (Hylaform) as compared to the normals and to the scarred group that received no hyaluronan (P ⬍ 0.01 and P ⬍ 0.05, respectively). Conclusion: Injection of scarred rabbit vocal folds with hyaluronan in the short term rendered improved viscoelastic parameters. Significance: Hyaluroan may prove useful for treating vocal fold scarring. Support: None reported. 10:48 AM Treatment of Vocal Fold Scar with an AutoCrosslinked Polysaccharide Hyaluronan-Based Gel Bernard Rousseau, MA (presenter); Ichiro Tateya, MD PhD; Jin-Ho Sohn, MD PhD; Nathan V Welham, MSLT; Charles N Ford, MD; Diane M Bless, PhD Madison WI; Madison WI; Madison WI; Madison WI; Madison WI; Madison WI
10:40 AM Viscoelasticity in Scarred Rabbit Vocal Folds after Hyaluronan Injection Stellan Hertegard, MD PhD (presenter); Ake R Dahlqvist, MD PhD; Eric Goodyer, MSc; Frans Maurer, PhD Stockholm Sweden; Umea Sweden; Leicester United Kingdom; Lund Sweden
Problem: Hyaluronan has been shown to improve the viscoelastic properties after injections in normal rabbit vocal folds and in patients with unilateral paresis and vocal fold atrophy. Viscoelasticity is important to the vocal fold vibratory capacity. The aim of the study was to analyze the
Problem: To examine the effectiveness of an autocrosslinked polysaccharide (ACP) hyaluronan-based gel for the treatment of acute vocal fold scar in a canine animal model. Methods: Twelve canine larynges were injured by unilateral stripping of the vocal fold mucosa, from the epithelium down to the thyroarytenoid muscle. Six of these animals were treated with a transcutaneous injection of ACP gel (30 mg) into the thyroarytenoid muscle and remaining lamina propria at the time of injury, and again at 7 and 14 days postoperatively. The remaining animals were treated with an injection of sodium chloride to serve as sham controls. All animals
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Otolaryngology– Head and Neck Surgery August 2004
Otolaryngology– Head and Neck Surgery Volume 131 Number 2
were euthanized 2 months following the initial treatment. Excised larynx experiments were completed to obtain phonation threshold pressure (PTP) and vocal economy an acoustic output cost ratio (OCR), followed by histologic analysis for hyaluronan and collagen between the scarred and control vocal fold. Results: Dense, thick bundle collagen was observed on the injured side of sham-treated larynges. Minimal collagen deposition was observed on the injured side of ACP-treated larynges. PTP was lower and OCR was higher in the ACPtreated animals. Conclusion: ACP-treated larynges revealed greater ease of phonation and better vocal economy than sham-treated larynges. Collagen deposition was less dense in ACP-treated larynges. ACP gel provided sufficient bulk to the scarred vocal fold. Significance: ACP gel may provide a useful bio-injectable substance for improving rheologic tissue and aerodynamic properties for phonation in the scarred larynx. Support: None reported.
and a greater percentage of animals demonstrated new clonal cell formation (72.7%-HA vs 54.5%-control) (P ⫽ 0.659). No differences were seen in connective tissue organization and epithelial closure. Conclusion: These results show that HA significantly decreases inflammation in tracheal wounds in a rabbit model. Although not statistically significant, the results also suggest that HA may be chondroprotective, as demonstrated in articular cartilage models. Significance: Poor wound healing including cartilage ring damage can contribute to airway compromise especially in an infant after tracheal surgery. This experiment suggests that HA may be useful as an adjunct in improving postoperative tracheal repair. Support: (1) The Friedberg Research Fund in the Department of Otolaryngology at Rush University Medical Center. (2) SEPRAPACK ™ and Hemaseel ™ were both donated by GYRUS ENT and HAEMACURE, respectively under no obligation by the authors.
10:56 AM
11:12 AM
The Effect of Hyaluronic Acid on Tracheal Wound Healing
Use of Bipolar Diathermy in Tonsillectomy Is a Powerful Risk Factor for Hemorrhage
Phillip Samuel LoSavio, MD (presenter); David L Walner, MD; James M Williams, PhD; Kelly A Kaiser; Victoria Mark; David D Caldarelli, MD Chicago IL; Highland Park IL; Chicago IL; Chicago IL; Chicago IL; Chicago IL
David A. Lowe, FRCSEd FRCS (presenter) London United Kingdom
Problem: Various methods have been studied to improve tracheal healing after surgery. Previous experiments have demonstrated the benefits of hyaluronic acid (HA) not only in wound healing in the tympanic membrane, skin, and articular cartilage but also in decreasing adhesions in abdominal operations. The goal of this project was to study the effects of hyaluronic acid on tracheal wound healing. Methods: Twenty-two New Zealand white rabbits, (11 experimental, 11 control) had a 2 mm round defect created in the third tracheal ring. The experimental group had an 8 mm round sodium hyaluronate-based sponge (SEPRAPACK™) fixed over the defect using fibrin glue (Hemaseel™). The control group had a plain 8 mm collagen sponge placed in a similar manner. Tracheal tissue was harvested at 4 weeks postop and histologically scored in regard to inflammation, connective tissue organization, epithelial closure, chondrocyte death, and cartilage regeneration (clonal cell formation) at the area of injury. Statistical analysis was done using the Mann-Whitney U and Fisher-Exact tests. Results: Inflammatory cell infiltration was significantly increased at the area of injury in the control group compared to the HA-treated wound (P ⫽ 0.014). In the HA-treated group a lower percentage of animals had chondrocyte death at the wound edge (45.5%-HA vs 81.8%-control) (P ⫽ 0.183)
Problem: Tonsillectomy remains among the most frequently performed surgical procedures. Bipolar diathermy for tonsillar dissection and/or hemostasis is the most popular technique in the UK. Although it allows good control of intraoperative bleeding, little evidence exists to support diathermy as superior to traditional “cold steel” dissection with only packs and ties for hemostasis. Excessive use of diathermy may further influence the occurrence of secondary haemorrhage. Methods: The National Prospective Tonsillectomy Audit (NPTA) is collecting data on the occurrence of complications following tonsillectomies performed since July 2003 in England and Northern Ireland. Postoperative hemorrhages and other complications within 28 days of surgery leading to delayed discharge, readmission, or return to theatre are recorded. On 23 February 2004, the Audit included data on 13,554 patients, of whom 11,796 (87%) from 252 different hospitals consented to electronic submission of their tonsillectomy data to the central database. Results: We demonstrated an overall hemorrhage rate following tonsillectomy of 3.3%. 2% of patients had a hemorrhage of sufficient severity to require return to the operating theatre. The relative risk of hemorrhage in the bipolar diathermy dissection and hemostasis group (relative to cold steel group) was 3.1 (95% CI 1.9 5.0; P ⬍ 0.0001). Use of cold steel for dissection but bipolar diathermy for hemostasis carried an intermediate risk of hemorrhage, (relative risk 2.2; 95% CI 1.3 3.7; P ⫽ 0.002). High diathermy power settings
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