Stridor in the Infant Patient.

Stridor is a high-pitched extrathoracic noise associated with turbulent airflow, commonly associated with respiratory distress in infants. Workup for stridor requires evaluation of the upper-respiratory airway, with severe distress requiring evaluation under anesthesia. The differential diagnosis of stridor depends on location of the obstruction, age of the patient, and acuity of the symptoms. The most common reason is laryngomalacia; most patients can be managed conservatively with resolution of symptoms by 2 years of age. In children who do not improve or have severe disease, supraglottoplasty is the treatment of choice, and the majority will have resolution of stridor postoperatively.

Barriers to Decannulation After Double-Stage Laryngotracheal Reconstruction.

OBJECTIVES/HYPOTHESIS: To identify any potential barriers for decannulation in children undergoing double-staged laryngotracheal reconstruction (dsLTR) beyond the severity of disease itself. STUDY DESIGN: Case series with chart review. METHODS: We performed a retrospective chart review from 2008 to 2018 of 41 children who had undergone dsLTR as primary treatment for laryngotracheal stenosis at a stand-alone tertiary children's hospital. We examined the effect of demographic, medical, and surgical factors on successful decannulation and time to decannulation after dsLTR. RESULTS: Of the 41 children meeting inclusion criteria who underwent dsLTR, 34 (82%) were decannulated. Age, gender, race, insurance status, medical comorbidity, and multilevel stenosis did not predict overall decannulation. Insurance status did not impact time to decannulation (P = .13, Log-rank). Factors that increased length of time to decannulation were the use of anterior and posterior cartilage grafts (P = .001, Log-rank), history of pulmonary disease (P = .05, Log rank), history of cardiac disease (P = .017, Log-rank), and race/ethnicity (P = .001 Log-rank). CONCLUSION: In a cohort with a similar decannulation rates to previous dsLTR cohorts, we identified no demographic or medical factors that influenced overall decannulation. We did observe that pulmonary comorbidity, cardiac comorbidity, and race/ethnicity lengthens time to decannulation. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2141-2147, 2021.

International Pediatric Otolaryngology Group (IPOG) management recommendations: Pediatric tracheostomy decannulation.

OBJECTIVES: To provide recommendations to otolaryngologists, pulmonologists, and allied clinicians for tracheostomy decannulation in pediatric patients. METHODS: An iterative questionnaire was used to establish expert recommendations by the members of the International Pediatric Otolaryngology Group. RESULTS: Twenty-six members completed the survey. Recommendations address patient criteria for decannulation readiness, airway evaluation prior to decannulation, decannulation protocol, and follow-up after both successful and failed decannulation. CONCLUSION: Tracheostomy decannulation recommendations are aimed at improving patient-centered care, quality and safety in children with tracheostomies.

Advanced practice providers and children's hospital-based pediatric otolarynology practices.

INTRODUCTION: Advanced practice providers (APPs), including nurse practitioners and physician assistants, have been deployed in children's hospital-based academic pediatric otolaryngology practices for many years. However, this relationship in terms of prevalence, roles, financial consequences and satisfaction has not been examined. The objective of this study is to explore how APPs impact healthcare delivery in this setting. METHODS: Pediatric otolaryngology chiefs of all academic children's hospitals in the US were electronically surveyed about the ways APPs intersected clinically and financially in their respective practice. RESULTS: A total of 29 of 36 children's hospital-based pediatric otolaryngology practices completed the survey, of which 26 practices (90%) utilized APP. There were large variances within the APP practice cohort in faculty size (mean/median/range = 9.4/8.5/3-29); annual patient visits (mean/median = 18,373/17,600); number of practice site (mean/median/range = 4.3/4/2-9) and number of outpatient APP (mean/median/range = 6.3/5/1-30). No factors (faculty size, annual visits and number of practice sites) differentiated between the APP and non-APP practices. Among APP practices, significant correlation (p<.00001) was observed between size of APP cohort to faculty size and annual visits. 69% of the practices did not differentiate job functions of nurse practitioners and physician assistants. 85% of the practices utilized APPs in all practice sites and 19% utilized APPs in the operating room. 77% of APPs billed independently and 46% had on-site supervision. The most prevalent APP salary bracket based on 0-5, 6-10 and > 11 years of tenure were $76-100K (65%), $100-150K (77%) and $100-150K (86%), respectively. In 46% of the practices, APPs were able to generate enough revenue to cover more than 75% of their salary and 23% of practices generated a profit. 81% of the chiefs ranked the effectiveness of APPs as high (4 and 5) on a 5-point Likert scale. DISCUSSION: The majority of academic pediatric otolaryngology practices employed APPs. Despite the diversity seen in practice complexity, APP functionality and financial impact, most found the APP model to be beneficial in improving patient care, patient access and faculty productivity.

International Pediatric Otolaryngology Group: Consensus guidelines on the diagnosis and management of type I laryngeal clefts.

INTRODUCTION: The diagnosis and management of type I laryngeal clefts can be controversial and varies across centers and surgeons. Using existing peer-reviewed literature to develop an expert-based consensus will help guide physicians in the treatment of these patients as well as develop research hypotheses to further study this condition. OBJECTIVE: To provide recommendations for the diagnosis and management of type I laryngeal clefts. METHODS: Determination of current expert- and literature-based recommendations, via a survey of the International Pediatric Otolaryngology Group, using a modified Delphi method. SETTING: Multinational, multi-institutional, tertiary pediatric hospitals. RESULTS: Consensus recommendations include diagnostic workup, medical management, pre-operative, intra-operative and post-operative considerations for type I laryngeal clefts. CONCLUSIONS: This guide on the diagnosis and management of patients with type I laryngeal clefts is aimed at improving patient care and promoting future hypothesis generation and research to validate the recommendations made here.

Otogenic lateral sinus thrombosis in children: A review of 7 cases.

Otogenic lateral sinus thrombosis (LST) is a rare but serious intracranial complication of acute or chronic otitis media. Reported mortality rates have ranged from 8 to 25%; the pediatric mortality rate might be as low as 5%. Controversy still exists over the medical and surgical management of this condition. We conducted a retrospective chart review of 7 cases of pediatric otogenic LST that were treated at our institution over a period of 8 years. We hypothesized that good outcomes in very sick patients can be achieved by aggressively managing the mastoid cavity and without the need for a thrombectomy. Our study group was made up of 4 boys and 3 girls, aged 6 to 15 years (mean: 11.1). All patients received intravenous antibiotics and underwent mastoidectomy with unroofing of the sigmoid sinus and placement of a tympanostomy tube. Sinus exploration with thrombectomy was not performed in any patient. Anticoagulation was used perioperatively in 5 patients (71%) without complication. All patients recovered well without major sequelae, which supports our hypothesis. We also describe the case of a patient with multiple concomitant intracranial comorbidities associated with this rare condition.

Trends in U.S. Pediatric Otolaryngology Fellowship Training.

IMPORTANCE: Interest in pediatric otolaryngology fellowship training is growing. The workforce implications of this growing interest are unclear and understudied. OBJECTIVES: To analyze trends in pediatric otolaryngology training, determine where fellows who graduated over the past 10 years are currently practicing, and test the hypothesis that graduates from Accreditation Council for Graduate Medical Education (ACGME)­accredited programs were more likely to have academic tertiary positions with faculty appointments. DESIGN, SETTING, AND PARTICIPANTS: We conducted a web-based analysis of pediatric otolaryngology fellowship graduates. The names of all 274 applicants who were matched to pediatric otolaryngology fellowships from May 31, 2003, to May 31, 2014, were obtained from the SF Match website. Accreditation status of each program for each match year was obtained from the ACGME website. We then performed an Internet search for the current practice location of each matched applicant. Analysis was conducted from January 1, 2015, to May 1, 2015. MAIN OUTCOMES AND MEASURES: Practice setting per year of fellowship match and accreditation status of program. RESULTS: For the 2003 to the 2014 match years, there was an increase from 5 to 22 accredited pediatric otolaryngology fellowship programs overall; simultaneously, the number of yearly matched applicants increased from 14 to 35. More graduates with ACGME accreditation practice at academic settings compared with graduates without ACGME accreditation although the difference was not statistically significant (67.1% vs. 50.7%; P = .15). Graduates from accredited programs, however, were significantly more likely to practice at a hospital-based setting compared with those from nonaccredited programs (81.7% vs. 65.5%; P = .003). Fellows trained in the last 10 years are relatively well distributed across the country. CONCLUSIONS AND RELEVANCE: The number of pediatric otolaryngology fellowship applicants as well as total number of matched applicants and ACGME-accredited positions has risen in the last 10 years. It appears that a higher proportion of fellows trained in accredited programs work in academic positions in hospital-based practices. The long-term effect on the pediatric otolaryngology workforce of training more fellows in accredited fellowships remains to be seen.

A comparative analysis of open surgery vs endoscopic balloon dilation for pediatric subglottic stenosis.

IMPORTANCE: Minimally invasive endoscopic techniques are an appealing alternative to open surgical management of pediatric subglottic stenosis (SGS), but more information is needed to understand the comparative risks, benefits, and limitations of such interventions. OBJECTIVE: To compare the effectiveness of endoscopic balloon dilation (EBD) and laryngotracheoplasty (LTP) in pediatric patients with SGS and to identify patient and disease factors that are associated with successful EBD. DESIGN, SETTING, AND PARTICIPANTS: A retrospective medical record review of children undergoing EBD and LTP for SGS in a tertiary care children's hospital from 2006 through 2012. MAIN OUTCOMES AND MEASURES: Success was defined as decannulation or tracheotomy avoidance. Additional outcomes were total number of procedures and number of unplanned procedures. Univariate χ2 analyses and multivariate regression analyses were performed to identify patient and disease factors statistically associated with success within treatment groups. RESULTS: Overall, 86 of 90 patients (96%) successfully avoided tracheotomy or were decannulated. Fourteen patients were successfully treated with EBD, but for 13 patients, EBD failed, and they underwent LTP. A total of 76 patients underwent LTP. In univariate analyses, patients for whom EBD was successful were more likely to have mild (grade 1 or 2; n = 10) than severe (grade 3 or 4; n = 4) SGS compared with patients for whom EBD failed (grade 1 or 2, n = 0 vs grade 3 or 4, n = 13) (P < .001). Three patients who underwent initial EBD had worsening stenosis. Patients initially treated with EBD were more likely to require unplanned surgical intervention during their treatment (6 of 27; 22%) than patients initially treated with LTP (3 of 63; 5%) (P = .01). Patients initially treated with EBD had a lower number of airway interventions and/or evaluations under anesthesia (mean, 6.7) during their course of treatment than patients initially treated with LTP (mean, 9.2) (P = .003). In multivariate analyses, only severe SGS was significantly associated with failure of initial EBD (13 of 13 [100%] with type 3 or 4 vs 4 of 14 with type 1 or 2 [29%]) (P = .002). CONCLUSIONS AND RELEVANCE: For severe SGS, EBD has limited application compared with LTP, and in some cases failed EBD is even detrimental, increasing the risk of unplanned urgent interventions compared with LTP.

Dexmedetomidine as a primary sedative agent after single-stage airway reconstruction.

OBJECTIVE: To examine the outcomes of children receiving dexmedetomidine after single-stage airway reconstruction. STUDY DESIGN: Historical cohort study. SETTING: Tertiary care children's hospital. SUBJECTS AND METHODS: Of 61 eligible patients, 50 children undergoing single-stage airway reconstruction were included in the study. Thirty children received dexmedetomidine (Dex) as a primary sedative agent, and 20 received a more traditional sedation protocol (no Dex). Primary outcomes included complications, intubation lengths, and lengths of pediatric intensive care unit (PICU)/hospital admission. Secondary analysis incorporating polypharmacy and age was performed using multivariate linear regression models. RESULTS: Median age was 18.0 months. Age, sex, and weight were similar between the groups. Intubation length was equal in the 2 groups, and there were no statistical differences between lengths of PICU or hospital stay after extubation. Similarly, overall and individual complications were all similar, and there was no difference between the 2 groups in the amount of polypharmacy administered. On multivariate analysis, polypharmacy and younger age were independently correlated with an increase in overall complications, and polypharmacy alone was correlated with an increased length of stay after extubation. CONCLUSION: The use of dexmedetomidine as a primary sedation agent after single-stage airway surgery does not appear to improve outcomes or decrease the need for additional pharmacologic agents. Polypharmacy was associated with an increase in overall complications and an increased length of stay after extubation. Although success can be expected in greater than 90% of these surgical patients, the optimal postoperative sedation management remains challenging.

"Natural" decannulation in patients with Robin sequence and severe airway obstruction.

OBJECTIVES: Airway management in infants with Robin sequence (RS) remains controversial, ranging from conservative to operative methods. In some centers, tracheostomy remains the mainstay for those infants with severe respiratory obstruction. The goals of this retrospective case cohort study were to determine the length of time to decannulation without further surgical intervention (ie, "natural" decannulation) in patients with severe RS who underwent tracheostomy and to investigate potential factors associated with successful decannulation. METHODS: We reviewed all infants with RS treated at a large tertiary center from 1994 to 2010. Patients who had undergone tracheostomy were identified. Baseline demographics, complications, deaths, and time to "natural" decannulation were recorded. Statistical analysis was performed with univariate analysis and Kaplan-Meier log-rank tests. RESULTS: Of 61 infants with RS with obstructive events, 25 infants (14 with isolated RS and 11 with syndromic RS) required tracheostomy. At a mean follow-up of 4 years, the rate of tracheostomy-specific complications was 52%; the tracheostomy-specific mortality rate was 12%. Overall, 13 of 25 infants (52%) were "naturally" decannulated, with a median time to decannulation of 97 months. Patients with syndromic RS had a significantly longer median time to decannulation than did those with isolated RS (more than 73 months versus 19 months, respectively; p = 0.019). In addition, patients with long-term tracheostomy dependence had significantly higher maximum carbon dioxide levels before tracheostomy than did patients who were successfully decannulated (82.4 versus 63.2 mEq/L, respectively; p = 0.02). CONCLUSIONS: Tracheostomy in infants with RS is associated with inordinately high rates of mortality, morbidity, and long-term tracheostomy dependence, particularly in patients with syndromic RS and in those with high maximum carbon dioxide levels before tracheostomy.

Balloon dilation for management of choanal atresia and stenosis.

OBJECTIVES: We describe our use of balloon dilation to repair choanal atresia in a series of patients. STUDY DESIGN: Case series. METHODS: We performed a retrospective review of patients who underwent repair of choanal atresia using dilation with high pressure, non-compliant airway balloons between January 2009 and September 2010. For primary cases, balloon dilation was used in conjunction with transnasal endoscopic puncture, and repair of bony stenosis with backbiting forceps and microdebrider drill. RESULTS: 5 patients underwent balloon dilation repair of choanal atresia or stenosis. 4 patients presented for primary repair, with a mean age of 2.9 months. 1 patient presented at 10 years of age for revision repair several years after previous attempts performed elsewhere. The average number of procedures was 3.6, with an average of 2 balloon dilations. There were no complications stemming from balloon dilation. Follow-up ranged from 3 to 24 months. All patients demonstrated choanal patency on last follow-up. CONCLUSIONS: This is a novel use of high pressure, non-compliant balloons. We found success in dilating membranous stenoses, post-repair granulation, and scar tissue in revision cases. Balloon dilation is an effective adjuvant tool for use in the repair of choanal atresia and stenosis.

Microdebrider-assisted supraglottoplasty for laryngomalacia.

OBJECTIVES: We describe our series in the surgical treatment of laryngomalacia using a microdebrider. METHODS: We performed a retrospective review of patients who underwent microdebrider-assisted supraglottoplasty for laryngomalacia between October 2004 and February 2008. Patients with neurologic conditions and secondary airway lesions were excluded. The main outcome measures included complications, pain, resolution of stridor, presence of aspiration, and need for revision surgery. RESULTS: Twenty-eight patients underwent microdebrider-assisted supraglottoplasty. The mean age at diagnosis was 109 days, and the mean age at the time of the procedure was 182 days. Nineteen patients (68%) had gastroesophageal reflux at diagnosis. The average operative time was 35.7 minutes (range, 11 to 65 minutes). No intraoperative complications or device problems occurred. Two patients remained intubated after the procedure. One patient required a tracheotomy, and 1 patient underwent revision supraglottoplasty. Three patients had aspiration that resolved. There was negligible pain from the procedure, as all patients immediately resumed a diet. All patients had immediate or eventual resolution of stridor. CONCLUSIONS: This is the largest series of patients who underwent microdebrider-assisted supraglottoplasty for laryngomalacia. This procedure is relatively safe, with minimal pain, and effective in patients with laryngomalacia. Microdebrider-assisted supraglottoplasty is the method of choice for supraglottoplasty in our institution.

Utility of bronchoscopy for recurrent croup.

OBJECTIVES: We performed a retrospective review to determine the utility of bronchoscopy in patients with recurrent croup (RC). METHODS: Bronchoscopy was performed on 30 patients with a diagnosis of RC (age, 14 months to 13.9 years) over a 2-year period. RESULTS: One third of the patients (33.3%) were found to have airway disorders, including subglottic stenosis (7), subglottic edema (2), and a subglottic cyst (1). Patients with RC who were less than 3 years of age were more likely to have an airway abnormality found on endoscopy (9 of 14 or 64.2%) than were those older than 3 years (1 of 16 or 6.2%; chi2 p < 0.001). There was no statistically significant difference in abnormal findings 1) in patients with RC who had a history of prematurity or prior intubations (chi2, p = 0.17 and p = 0.052, respectively); 2) between infectious and spasmodic croup (chi2, p = 0.794); or 3) by number of croup episodes (chi2, p = 0.300). Two patients required surgical intervention (laryngotracheal reconstruction and marsupialization of a subglottic cyst). CONCLUSIONS: Of 30 patients who underwent bronchoscopy for RC, 33% had airway disorders--mostly children less than 3 years old. We suggest a higher index of suspicion for finding airway disorders in children less than 3 years old with RC and having a lower threshold for performing diagnostic bronchoscopy in this population.

Management of pediatric orbital cellulitis in patients with radiographic findings of subperiosteal abscess.

OBJECTIVE: Controversies remain regarding the management of orbital cellulitis (OC). The objective of this study was to examine the outcomes of patients admitted to our institution for orbital cellulitis during a 7-year period. STUDY DESIGN: Case series with chart review. SETTING: Tertiary referral pediatric hospital. SUBJECTS AND METHODS: Charts of 465 consecutive OC admissions were reviewed for presentation, imaging, medical and surgical treatment, and outcome. RESULTS: Of these patients, 189 were treated in the emergency room and 276 were admitted. CT scan was performed on 240 patients. Subperiosteal abscess (SPA) was noted in 68 patients. Of these, 47 were treated medically and 21 had surgery. Surgical patients were older (8.3 vs 6.2 years, P = 0.039), had larger abscesses (>10 mm, P < 0.001), required a longer admission (10.2 vs 6.6 days, P < 0.001), and had higher temperatures on admission (38.0 degrees C vs 37.3 degrees C, P = 0.03). CONCLUSION: The majority of small SPAs as diagnosed on CT scans in younger children can be successfully treated medically. Surgery, however, should be considered for a worsening clinical examination. Our findings confirm those of previous reports on this clinical entity.

Necrotizing epiglottitis and hemophagocytic lymphohistiocytosis.

With the introduction of vaccination for haemophilus influenza, the epidemiology of epiglottitis in children has changed. Classic childhood epiglottitis is now rare, and unusual forms of the disease may be seen. Nectrotizing epiglottitis is an extremely rare form of epiglottitis. Only four cases of nectrotizing epiglottitis have been previously reported, and all cases were in immunocompromised adult patients. Hemophagocytic lymphohistiocytosis is a rare condition characterized by high fevers, hepatosplenomegaly, and cytopenias caused by an abnormal proliferation and activation of macrophages. We report the first case of a previously healthy 5-year-old male presenting with acute onset of airway distress and pancytopenia. Subsequent airway evaluation led to the diagnosis of nectrotizing epiglottitis, and he was simultaneously diagnosed with infection-induced hemophagocytic lymphohistiocytosis. The patient recovered with intubation and antibiotics. Follow-up direct laryngoscopy revealed an epiglottis remnant with approximately 50% loss of epiglottic tissue. The presentation and pathophysiology of this unusual manifestation of epiglottitis and hemophagocytic lymphohistiocytosis will be reviewed. In the post-haemophilus influenze vaccination era, the pediatric otolaryngologist must be familiar with unusual forms of epiglottitis and its associated manifestations.

Safety and outcomes of outpatient pediatric otolaryngology procedures at an ambulatory surgery center.

OBJECTIVES: To determine the safety and outcomes of outpatient pediatric otolaryngology procedures performed at an ambulatory surgery center (ASC). METHODS: Retrospective review of all pediatric otolaryngology cases performed at a freestanding, outpatient ASC of a tertiary care, academic children's medical center from 2000 to 2007. RESULTS: Of all cases, 4979 (55%) were otolaryngology procedures. Twelve surgeons and 10 pediatric anesthesiologists staffed the cases; no residents/fellows were involved. The case breakdown is as follows: 2045 (41.1%) myringotomy and tympanostomy tube; 1438 (28.9%) adenoidectomy (with tympanostomy tube placement and/or turbinectomy); 880 (17.7%) tonsillectomy (with or without adenoidectomy). According to American Society of Anesthesiologist (ASA) classification: 84.2% were ASA I, 15.1% ASA II, 0.7% ASA III. There were nine unanticipated outcomes: four postadenotonsillectomy and one postadenoidectomy bleeds (three requiring reoperation the same day), two patients with low psuedocholinesterase levels, one postadenotonsillectomy patient requiring overnight monitoring, and one patient with an incidental finding of a subglottic mass. Preoperative ASA status on these nine patients was 7 (78%) ASA I, 2 (22%) ASA II. CONCLUSIONS: Pediatric otolaryngology procedures constitute significant volume at our ASC. Surgery at our ASC is extremely safe with a rate of unanticipated outcomes of 0.2%--a comparison not available in the literature. Pediatric otolaryngology procedures performed with a highly skilled team at an outpatient ASC result in high quality and safe surgery.

Resource utilization in the management of subglottic stenosis.

OBJECTIVE: The purpose of this study was to determine resource utilization in managing subglottic stenosis. STUDY DESIGN: The Kids' Inpatient Database (KID) 2003 was analyzed. SUBJECTS AND METHODS: International Classification of Diseases, Ninth Revision code 478.74 was the inclusion criteria. RESULTS: Two thousand forty-six admissions with subglottic stenosis were sampled; there were 10 deaths (0.49%). States with the most admissions were Ohio, California, and Illinois; these did not have the highest spending per admission. Two hundred eighteen (10.7%) underwent a laryngeal graft procedure; states with the most were Ohio (35.8%), Texas, California, and Florida. Indicators of increased resource utilization include length of stay, nonelective admission, race, primary payer, hospital location, and type. CONCLUSIONS: For subglottic stenosis, three states account for 37% of admissions, and four states account for 56% of laryngeal graft procedures in 2003. The mean total charges were $53,787; 90% of admissions had total charges less than $139,253. Patients who underwent surgical procedures had total charges of $76,409.

Localization and expression of MUC5B and MUC7 mucins in pediatric sinus mucosa.

OBJECTIVES: The purpose of this study was to analyze the secretory cell population and distribution of MUC5B and MUC7 mucins in the sinus mucosa of pediatric patients with and without chronic rhinosinusitis (CRS). METHODS: Sinus mucosal specimens were collected at surgery in a pediatric tertiary care facility. Histologic, immunohistochemical, and morphometric analyses were performed on sinus mucosa of 20 children with CRS and 7 children without CRS. RESULTS: A significant increase in the area of submucosal glands was evident in the sinus mucosa of children with CRS as compared to controls. MUC5B and MUC7 mucins were expressed in the submucosal glands, as well as in goblet cells, in the sinus mucosa of both populations. No differences in MUC5B or MUC7 expression were observed when mucin expression was normalized to glandular area. CONCLUSIONS: Children with CRS have an increased number of submucosal glands, indicating that glandular mucins contribute to mucus overproduction in CRS. MUC5B and MUC7 mucins, which have previously been considered only glandular mucins, are also expressed in goblet cells in the sinus mucosa.

Laryngotracheal stenosis repair using cartilage-derived morphogenic proteins: A pilot study.

OBJECTIVES: This pilot study evaluated the role of cartilage-derived morphogenic proteins (CDMPs) as promoters of cartilage growth and differentiation and as a possible alternative to autologous cartilage grafts in laryngotracheal reconstruction. METHODS: In phase 1, 6 New Zealand rabbits underwent subperichondrial injection of CDMP-1, CDMP-2, or CDMP-3 in the right thyroid ala and normal saline solution in the left thyroid ala as controls. In phase 2, 14 rabbits underwent anterior cricoid split and interposition of a fibrillar collagen sponge saturated with normal saline solution, CDMP-2, or CDMP-3. RESULTS: In both phases, saline solution failed to induce new cartilage or bone growth. Small foci of cartilage and/or bone formation were observed within the thyroid subperichondria of those rabbits injected with CDMP-2 or CDMP-3. In phase 2, a few small foci of new cartilage and/or bone formation were observed at the edges of the cricoid split with CDMP-2 and CDMP-3. CONCLUSIONS: A different carrier of CDMP, a change in dosage, or a combination of CDMPs might yield more significant neochondrification. The role of CDMPs as promoters of cartilage and differentiation could not be disqualified in this study and should be further investigated.