Protective effect of immunosuppression on granulation tissue formation in metallic airway stents

Objectives/Hypothesis: The use of self‐expanding metallic airway stents has been extended in recent years in inoperable patients with malignant and benign airway diseases. The risk of granulation tissue formation in the stent is a major concern. The objective of the present study was to determine whether immunosuppression modulates granulation tissue formation in airway stents, as seen in coronary stents. Study Design: The study included 19 patients with benign airway obstructions and 11 recipients of lung transplants with anastomotic obstructions who were receiving immunosuppression therapy. Methods: The degree of in‐stent granulation tissue formation was evaluated (score range, 0–3) every 3 months for 2 years. Results: Granulation tissue formation was significantly lower in the transplant recipients than in the nontransplant patients at 3 months (score 0.7 vs. 1.6, P = .031), 15 months (score 0 vs. 1.1, P = .026), and 18 months (score 0 vs. 1.8, P = .020). During the 2 years of follow‐up, the transplant recipients underwent significantly fewer laser resections and brachytherapy treatments for in‐stent granulation. Conclusions: The immunosuppression given to lung transplant recipients may have an inhibitory effect on granulation tissue formation in metallic airway stents. Further studies are needed to evaluate the effect of systemic therapy or coated stents with drugs such as sirolimus.     

Microbiology of stents in laryngotracheal reconstruction

OBJECTIVES: Granulation tissue often forms around a laryngotracheal stent, tracheostomy tube, or other airway prosthesis, especially if infection occurs. We studied the types and frequency of organisms colonizing stents used in pediatric laryngotracheal reconstruction. STUDY DESIGN: This prospective study included 21 patients undergoing 23 consecutive laryngotracheal reconstructions with stents between 1991 and 1999. METHODS: After endoscopic removal, each laryngotracheal stent was placed immediately in a sterile container and transported to the laboratory. Specimens for culture were obtained from biofilms on the stents and plated on agars for growth of aerobic, anaerobic, and fungal organisms. Culture results were analyzed with regard to patient age, duration of stenting, and graft type. RESULTS: All stents were colonized with more than one pathogen (range 2-7). The most frequent aerobic isolates were Streptococcus viridians, Pseudomonas aeruginosa, Staphylococcus aureus,Haemophilus influenza, and Neisseria species. Anaerobic organisms were isolated in 26% of cases. Candida species were isolated in 57% of the cases; patients whose stents were colonized with Candida were significantly (P =.007) older (mean 77.5 months) than those not colonized with this organism (mean 26.1 months) CONCLUSIONS: The antibiotic agents currently used for children undergoing laryngotracheal reconstruction target mainly aerobic organisms. Despite prophylactic measures, the incidence of granulation tissue formation is clinically significant, and the prevalence of anaerobic, including fungal, pathogens is high. Antibiotic therapy directed toward controlling anaerobic and fungal organisms could help in controlling local inflammation and thus granulation tissue formation.     

Ten-year review of laryngotracheal reconstruction for paediatric airway stenosis

OBJECTIVES: To review the outcomes of paediatric patients with laryngotracheal stenosis treated at our institution by laryngotracheal reconstruction (LTR). METHODS: A single surgeon personal series retrospective review of case notes over a 10-year period from a single site tertiary referral paediatric otolaryngology department in patients with laryngotracheal stenosis treated with laryngotracheal reconstruction. Evaluation was based on the last laryngotracheal endoscopy, and a retrospective review of the patient's data. RESULTS: Seventy-three open laryngotracheal procedures were undertaken for paediatric laryngotracheal stenosis from the period 1995-2005. Fourteen were cricoid split operations and will be described elsewhere. The remaining 59 procedures were cartilage graft laryngtracheal reconstructions, performed on 53 patients (37 single stage and 16 staged) with 6 having required revisions. CONCLUSIONS: LTR provides good results for subglottic stenosis (SGS) as primary or salvage operations. The procedure has no deleterious effects on laryngeal growth. The causes of failed procedures are discussed.     

Management of pediatric airway granular cell tumor: role of laryngotracheal reconstruction

OBJECTIVE: To discuss the role of laryngotracheal reconstruction (LTR) in granular cell tumor (GCT) and to highlight the importance and seriousness of GCT in pediatric airway cases. METHODS: A historical literature review was performed and a GCT case from the University of Miami Pediatric Otolaryngology Clinic is presented to highlight the role of LTR in the treatment of GCT. RESULTS: A case of a GCT of the laryngotracheal airway is reported and the management is discussed. Histological discussion and a review of the literature are included regarding GCT. This case is the third reported in the English literature of two synchronous GCT lesions of the upper airway repaired with a laryngotracheal reconstruction. CONCLUSIONS: In the authors' experience once conservative management consisting of endoscopic debulking has failed the treatment of choice for GCTs of the pediatric airway that are unresectable is a single stage laryngotracheal reconstruction with negative frozen section pathology to assure total wide local excision.     

Use of stents in laryngotracheal reconstruction in children: Indications,technical considerations,and complications

The keys to successful outcome in surgical repair of laryngotracheal stenosis in children are choice of surgical procedure, including possible need for stenting; choice of type and length of stent; and duration of stenting. Choosing the appropriate method for stenting requires considering consistency of stenosis, altered anatomy, size, location, and stability of grafts when used for surgical repair and host tissue healing factors. Possible stents that can be used include endotracheal tubes, Silastic® sheet rolls, Montgomery T-tubes, and laryngeal stents. This study investigates the effectiveness of the Aboulker stent, an increasingly popular stent for use in children. Indications and associated technical considerations for using the stent in 18 cases are reviewed. Postoperative care and follow-up, directed against infection and towards securing the stent in its original location, and management of complications are discussed.     

Simulated reflux and laryngotracheal reconstruction: a rabbit model

OBJECTIVES: (1) To test the feasibility of a rabbit model using a pharyngostomy tube to simulate gastroesophageal reflux and (2) to study the effects of gastroesophageal reflux on laryngotracheal reconstruction using a new rabbit model. DESIGN: Prospective randomized trial. SUBJECTS: Thirty-three New Zealand white rabbits. INTERVENTIONS: Anterior cartilage laryngotracheoplasty and pharyngostomy tube placement into the pyriform sinus were performed in 33 rabbits, 22 of which are included in this analysis. Beginning postoperative day 1, hydrochloric acid at a pH of 1.5 with pepsin (n = 7) or at a pH of 4.0 with pepsin (n = 8) was irrigated twice daily through the pharyngostomy tube to simulate gastroesophageal reflux, and a control group received twice-daily isotonic sodium chloride solution irrigations (n = 7). MAIN OUTCOME MEASURES: Specimens were scored by a pathologist masked to individual groups using a newly modified inflammation scoring system. In addition, cross-sectional areas of the cartilage grafts and subglottic airway lumina were compared. RESULTS: Inflammation scores were significantly higher in rabbits receiving hydrochloric acid and pepsin irrigations at a pH of 4.0 (P =.04) but not in those in the pH 1.5 group. Cartilage necrosis was prominent in all groups, and airway sizes and cross-sectional areas of the grafts were not significantly different among the 3 groups. CONCLUSIONS: Cartilage necrosis is prominent during the early stages after laryngotracheoplasty. Inflammation can be increased using hydrochloric acid and pepsin irrigations but is difficult to predict based on this study. Although we confirmed the feasibility of this model, further modifications of this study are proposed to improve animal survival and data collection.     

The effects of mitomycin-C and stenting on airway wound healing after laryngotracheal reconstruction in a pig model

OBJECTIVE: To assess the effects of mitomycin-C (MTC) and endoscopic stenting on airway wound healing after laryngotracheal reconstruction. DESIGN: A prospective, blinded, randomized controlled animal study. SUBJECTS: Twenty-six domestic pigs (Sus scrofula) divided into four groups. INTERVENTIONS: Each animal underwent single-stage laryngotracheal reconstruction (SSLTR) with auricular cartilage grafts and stenting. Group 1 animals were sacrificed on postoperative day 3, and group 2 animals on postoperative day 7. On postoperative day 7, groups 3 and 4 underwent endoscopy, stent removal, and application of MTC (0.5 mg/ml) or placebo (normal saline). Group 3 animals were sacrificed on postoperative day 14, group 4 animals on day 21. Two additional animals from each experimental group were prepared for election microscopy studies. Segments of reconstructed airway were evaluated grossly and histologically for all animals. Additional tonometric evaluation was performed on two stents to determine their compressive strength. MAIN OUTCOME MEASURES: Healing, reepithelization, graft incorporation, and airway diameter. RESULTS: Two-thirds of the animals demonstrated some degree of stent collapse on endoscopy. Granulation tissue formation was seen in all animals, and resolved with stent removal. No animal experienced airway compromise due to granulation tissue formation. Stenting was seen to induce a submucosal fibroproliferative response and scarring, with loss of normal glandular architecture, in all animals. MTC did not affect the acute inflammatory response, reepithelization of the graft site, or formation of the subepithelial fibroproliferative response. MTC treated animals, however, demonstrated better graft incorporation with fibrocartilage proliferation of the graft. Untreated animals demonstrated liquefactive necrosis of the graft, without evidence of neochondrification of the graft. CONCLUSIONS: The pig airway is an adequate model of wound healing following SSLTR and stenting. Metallic ballon expandable stents can be successfully used following SSLTR, allowing for immediate postoperative extubation. However, the formation of a submucosal fibroproliferative response and mucosal scarring seen in our study raises some concerns with the current stent design. Before stenting is widely clinically applied, the optimum stent design needs to be developed. Finally, MTC seems to prevent the liquefactive necrosis of SSLTR grafts and promote neochondrification, allowing improved graft incorporation. Further studies are needed to asses the long-term effects of MTC on healing and restenosis, and its effects on cartilage growth and formation, following SSLTR.     

Regular tracheostomy tube changes to prevent formation of granulation tissue

OBJECTIVES/HYPOTHESIS: Tracheostomy is a commonly performed operative procedure that has been described since 2000 B.C. The early indications for tracheostomy were for upper airway obstruction, usually occurring in young people as a result of an infectious process. Recently, tracheostomies are more commonly performed in the critically ill patient to assist in long-term ventilatory support. Granulation tissue at the stoma and the trachea has been described as a late complication resulting in bleeding, drainage, and difficulty with maintaining mechanical ventilatory support. STUDY DESIGN: The present report is of an observational study of a newly implemented policy that required regular changing of tracheostomy tubes. Comparable groups of patients were compared before and after this procedural change to document complications. Data collection consisted of chart reviews of all admissions for 1 year before the policy change and the subsequent 2 years. Complication rates were compared using standard statistical techniques. METHODS: A policy change was instituted that required all tracheostomy tubes to be changed every 2 weeks in conjunction with a detailed evaluation of the tracheostomy stoma. Charts were reviewed the year before the change in policy and in the subsequent 2 years to determine the incidence of granulation tissue requiring operative intervention. RESULTS: The number of patients requiring surgical intervention secondary to granulation tissue showed a statistically significant decrease (P =.02). A review of policies and procedures from the six largest hospitals in southeastern Michigan had no recommendations for routine tracheostomy tube changes. CONCLUSIONS: A policy requiring a routine change of tracheostomy tubes results in fewer complications from granulation tissue. Tracheostomy tube changes to prevent granulation tissue and its complications.     

Results of full-thickness laryngotracheal wall reconstruction: a survey of the literature

Full-thickness reconstruction of the laryngotracheal wall is needed after tumour removal, and also in patients where lumen augmentation is required to resolve laryngotracheal stenosis. For repairing such defects, several techniques are available. All techniques are more successful when small defects are reconstructed and less successful when there is a major deficit. The main problem with most methods of reconstruction is their unreliable blood supply which becomes most obvious in repairing larger areas.     

The significance of post-operative fever following airway reconstruction

Objective

Post-operative management of children undergoing airway reconstruction has been well-described. However, many of these patients develop post-operative fevers. We conducted a retrospective review in an attempt to define the significance of post-operative fever following pediatric airway reconstruction.

Method

Retrospective analysis of 78 pediatric laryngotracheoplasties (LTPs) from May 1, 2006 - April 30, 2007 at a tertiary care pediatric hospital. Fever was defined as temperature ≥38.5. A fever was “significant” if accompanied by a positive sputum, blood or urine culture, or an elevated WBC. Chest radiograph (CXR) results and co-morbidities were examined.

Results

Forty-five percent of cases (35/78) had fever. Of those febrile, 46% (n = 16) had significant fever. Overall, 20.5% had significant fevers. Fifty-two cases were single-stage LTP (SSLTP) with 31 febrile and 26 cases were double-stage LTP (DSLTP) with 4 febrile. SSLTP cases were at a significantly greater risk for post-operative fever compared with DSLTP, 59% vs 15% respectively (p = 0.0002). 42% of febrile SSLTPs (n = 13) had significant fevers compared to 50% (n = 2) of febrile DSLTPs (Fisher's Exact p = 1.0). 81.5% of cases with CXR findings had fevers, but only 50% of these fevers were significant. Subjects with post-operative atelectasis were more likely to have a fever compared to subjects with no post-operative atelactasis (93% vs. 33% respectively, p < 0001). 30.8% of those with atelectasis had significant fever, compared to 52% of those without atelectasis (p = 0.2) and 25 of SSLTPs vs. 3.9% of DSLTPs had atelactasis (p = 0.027). No comorbidities were shown to be significant risk factors for post-operative fever.

Conclusion

Based on our review, most children undergoing LTPs will have insignificant fevers. Those children undergoing SSTLP and/or having post-operative atelectasis are at higher risk for post-operative fever. Fevers in children with double-stage procedures or all reconstruction cases with CXR findings other than atelectasis should have a thorough fever work-up.     

Results of full-thickness laryngotracheal wall reconstruction: a survey of the literature.

Full-thickness reconstruction of the laryngotracheal wall is needed after tumour removal, and also in patients where lumen augmentation is required to resolve laryngotracheal stenosis. For repairing such defects, several techniques are available. All techniques are more successful when small defects are reconstructed and less successful when there is a major deficit. The main problem with most methods of reconstruction is their unreliable blood supply which becomes most obvious in repairing larger areas.     

Polyglycolic acid/poly-L-lactic acid copolymer use in laryngotracheal reconstruction: a rabbit model

Objective: To evaluate the tissue response and resorption of the polyglycolic acid/poly‐L‐lactic acid (PGA/PLLA) implant in laryngotracheal reconstruction and compare its dynamic stability with autologous cartilage grafts. Study Design: An interventional, before‐after trial. Methods: Twenty‐one white, female, New Zealand rabbits were divided into four groups. Groups A and B underwent laryngotracheoplasty using the PGA/PLLA implants of 3 and 4 mm widths. Group C received autologous ear cartilage grafts. Group D was the control group and did not undergo surgery. The subjects were sedated at 12 months, and the larynges were evaluated in vivo for stability and area measurements by way of endoscopy during spontaneous respiration. The subjects were then killed, the larynges harvested, and the negative intraluminal pressures applied to the laryngotracheal unit were measured in a closed‐system apparatus. The larynges were then evaluated for inflammatory reaction and implant resorption by way of histologic analysis. Results: All implanted subjects survived without complications and grew normally. There was no appreciable subglottic collapse during spontaneous respiration under anesthesia. Ex vivo examination of maximum negative intraluminal pressures (?50 cm H₂O) in a closed system demonstrated subglottic collapse of 78%, 72%, 61%, and 3% for groups A, B, C, and D, respectively, revealing the inherent weakness in the surgically manipulated airways regardless of grafting material. Histologically, the PGA/PLLA implants were essentially completely resorbed. Conclusions: PGA/PLLA appears to be a safe and effective synthetic material for use in laryngotracheal reconstruction in the rabbit model while avoiding donor site morbidity and additional operative time. Reconstructed airways maintained adequate strength and patency under physiologic conditions and are comparable with autologous cartilage grafts.     

Topical mitomycin application after laryngotracheal reconstruction: a randomized, double-blind, placebo-controlled trial

OBJECTIVE: To explore the effect of mitomycin treatment on the pediatric airway following laryngotracheal reconstruction. DESIGN: Randomized, double-blind, placebo-controlled trial. PATIENTS: Children aged 2 to 17 years with subglottic or upper tracheal stenosis undergoing laryngotracheal reconstruction at a single, tertiary care, children's hospital. INTERVENTION: At the time of extubation or stent removal, the children underwent bronchoscopy and 0.4 mg/mL (2 mL of a 0.2-mg/mL solution of either mitomycin or an equal volume of isotonic sodium chloride was directly applied to the subglottic region for a single application of 2 minutes. These children then underwent interval endoscopy at 2 weeks, 6 weeks, and 3 months postoperatively for assessment of their airways. RESULTS: Granulation tissue was graded on a scale of 0 (none) to 4 (near-total or total occlusion). Videotapes of endoscopies were independently observed and graded by 3 pediatric otolaryngology fellows with a subsequent interobserver agreement of 91.6%. The results were then dichotomized to represent a single cohort in which further surgical intervention would be required and another separate cohort in which further surgery would not be required. At the 1-year mark, interim analysis was performed by a Data Safety and Monitoring Committee. At this time, 13 children had been randomized to the mitomycin-treated arm of the study and 11 children to the placebo-treated arm. A 2-tailed Fisher exact test revealed a value of 1.00. The Data Monitoring and Safety Committee advised that the trial should be stopped because the distributions between the 2 populations were almost identical. CONCLUSION: We cannot reject the null hypothesis that a single topical dose of mitomycin exerts an equal benefit as does isotonic sodium chloride when applied to the pediatric airway after laryngotracheal reconstruction.     

Aerodynamic and acoustic assessment in children following airway reconstruction: An assessment of feasibility

Objective

The purpose of this study was to examine the feasibility of conducting aerodynamic and acoustic assessment in children following airway reconstruction. Underlying etiologies, co-morbidities and age related factors can present challenges for meaningful instrumental data collection in this population.

Methods

A chart review of 100 children who were seen for a complete voice evaluation at the Center for Pediatric Voice Disorders at the Cincinnati Children's Hospital Medical Center was conducted. Children who completed full or partial aerodynamic and acoustic protocols were identified. Data regarding the ability to participate in the assessment was tabulated, and vowel samples taken from the acoustic data were subjected to signal type classifications (e.g., Type I, II, III).

Results

Fifty-three children met the inclusion/exclusion criteria of the chart review. Of those children, 58% (n = 31/53) were able to complete the full acoustic and aerodynamic protocols without any modification. In regards to the aerodynamic protocol alone, 64% (n = 34/53) could complete protocol. In regards to the acoustic protocol alone, 75% (n = 40/53) could complete the entire acoustic protocol without any modification. There were 32% (n = 17) who provided a Type I acoustic signal which was appropriate for measurement of F₀. There was a significant correlation between age and ability to complete the protocol for both the aerodynamic (p = .007) and acoustic (p = .004) protocols.

Conclusions

This study demonstrated that a majority of children were capable of completing aerodynamic and acoustic protocols. A significant proportion of children in this study had severe dysphonia, precluding the ability to extract fundamental frequency. Although aerodynamic and acoustic measures are feasible for many patients in this population, the severity of dysphonias observed in these patients causes the use of these measures to be limited in some cases for documenting behavioral and surgical outcomes measures.     

Pediatric airway reconstruction at Great Ormond Street: a ten-year review. II. Revisional airway reconstruction.

One hundred eight consecutive patients with pediatric laryngotracheal stenosis requiring airway reconstruction over a 10-year period were reviewed. Thirty-two patients required revisional airway reconstruction in an attempt to achieve decannulation. Patients underwent from one to four revisional airway reconstructions, most often laryngotracheal reconstruction with costal cartilage grafting. In the Cotton grading scheme of preoperative stenosis, those patients requiring revisional airway surgery tended to come from the more severely affected categories. Twenty-two patients of 32 (69%) achieved decannulation with revisional airway reconstruction. Thus, revisional airway reconstruction is indicated if the first attempt fails.     

奥美拉唑预防治疗喉部分切除术后喉腔肉芽的疗效分析

目的 观察喉部分切除术后口服奥美拉唑肠溶胶囊预防喉腔肉芽形成的疗效。方法 选取我院2017年1月—2022年5月收治的74例行喉部分切除术患者,将其随机分为对照组和实验组两组。对照组47例,出院后常规给予预防性抗感染治疗;实验组27例,出院后除预防性抗感染治疗外再加用口服奥美拉唑肠溶胶囊治疗,每日口服1次,每次20 mg,连用1个月。随访观察两组喉腔肉芽情况。结果 术后1个月电子喉镜显示经过奥美拉唑肠溶胶囊预防治疗后喉腔肉芽的发生率降低,与对照组相比,两者之间差异具有统计学意义(P<0.05)。结论 喉腔肉芽是喉部分切除术后常见的并发症之一,口服奥美拉唑肠溶胶囊可能是喉部分切除术后预防喉腔肉芽形成的有效治疗方案。