Subglottic stenosis of the larynx in the infant and child. Methods of management

Degrees of Inflammation in the Treatment of Subglottic Stenosis in a Rabbit Model: Histopathological Assessment of a Novel Bioabsorbable Ultra-high Ductility Magnesium Alloy Stent

OBJECTIVE

Utilizing a novel histopathological scoring system and subglottic stenosis (SGS) rabbit model, we aimed to compare degrees of inflammation and severity of narrowing in the subglottis between two minimally invasive therapeutic modalities: endoscopic balloon dilation (EBD) alone versus EBD with placement of a bioabsorbable ultra-high ductility magnesium (UHD-Mg) alloy stent.

METHODS

SGS was induced endoscopically via microsuspension laryngoscopy in 23 New Zealand white rabbits. The control group (n = 11) underwent EBD alone, the study arm (n = 12) underwent EBD with implantation of bioabsorbable UHD-Mg alloy stents. Rabbits were euthanized at 2-, 3-, and 6-weeks after SGS induction, coinciding with wound healing stages. Using Optical Coherence Tomography (OCT), cross-sectional areas of airways were compared to calculate the mean percentage of intraluminal area at sequential time points. A novel histopathological scoring system was used to analyze frozen sections of laryngotracheal complexes. The degree of inflammation was quantified by scoring changes in inflammatory cell infiltration, epithelial ulceration/metaplasia, subepithelial edema/fibrosis, and capillary number/dilation. Univariate analysis was utilized to analyze these markers.

RESULTS

We found rabbits implanted with the bioabsorbable UHD-Mg alloy stent had statistically significantly higher scores in categories of hyperplastic change (stents vs controls: 1.48 vs 0.46 p < 0.001), squamous metaplasia (22 vs 5 p < 0.001), and neutrophils/fibrin in lumen (31 vs 8, p < 0.001). Rabbits who received EBD alone had higher scores of subepithelial edema and fibrosis (2.70 vs 3.49, p < 0.0256). The stented rabbits demonstrated significantly increased mean percent stenosis by intraluminal mean area compared to controls at 2 weeks (88.56 vs 58.98, p = 0.032), however at all other time points there was no significant difference between intraluminal subglottic stenosis by mean percent stenosis area.

DISCUSSION

Rabbits with SGS treated with UHD-Mg alloy stents demonstrated histopathologic findings suggestive of lower levels of tracheal fibrosis. This could indicate a reduced tendency towards the development of stenosis when compared to EBD alone. There was not a difference in luminal size between stent and non-stented rabbits at the six-week end point. Histologically, however, overall the use of bioabsorbable UHD-Mg alloy stenting elicited a greater tissue response at the level of the superficial mucosa rather than fibrosis of the lamina propria seen in the stented rabbits. This suggests more favorable healing and less of a tendency towards fibrosis and stenosis even though there may not be a benefit from a luminal size standpoint during this early healing period. Compared to known complications of currently available non-bioabsorbable metal or silicone-based stents, this proof-of-concept investigation highlights the potential use of a novel biodegradable UHD-Mg stent as a therapeutic modality for pediatric SGS.

Complications associated with costal cartilage harvest in pediatric laryngotracheal reconstruction

Objective

We aimed to determine the rate of complications associated with autologous costal cartilage graft harvest for pediatric laryngotracheal reconstruction (LTR). Secondarily, we sought to identify risk factors associated with the harvest of autologous costal cartilage, as well as evaluate management strategies.

Data Sources

An electronic database search of Ovid MEDLINE, Ovid EMBASE, and PubMed was completed for articles pertaining to complications in autologous costal cartilage harvest for pediatric LTR.

Review Methods

This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. The study characteristics, operative information, and patient demographics were collected. The data concerning postoperative complications, risk factors, and management strategies were collected and analyzed for patterns.

Results

A total of 31 manuscripts representing 745 patients were included for analysis. The reported donor site complications included pneumothorax (n = 13, 1.74%), pleural tear (n = 5, 0.67%), infection (n = 8, 1.07%), and scar-related problems (n = 2, 0.26%). There were no reported cases of seroma, persistent pain, or chest wall deformity. Only five studies discussed the management of donor site complications, with intervention in 11 (39.28%) patients including chest tube drainage and steroid injection.

Conclusion

There is significant variability in the literature regarding complication rates in autologous costal cartilage harvest for pediatric LTR. The incidence of major postoperative complications is low and supports the use of autologous costal cartilage as graft material for pediatric LTR.

Level of Evidence

NA.

Subglottic Stenosis in Children: Preliminary Experience from a Tertiary Care Hospital

INTRODUCTION

This retrospective study describes our experience in the evaluation and management of infants with subglottic stenosis.

MATERIALS AND METHODS

The study included 10 patients aged between 1 wk and 18 months with 6 cases having congenital subglottic stenosis and 4 cases having acquired subglottic stenosis.

RESULTS

6 patients had grade I, 3 patients had grade II, and 1 patient had grade III subglottic stenosis. Tracheostomy was required in 4 patients at the time of presentation. 7 patients were treated successfully with Bougie dilation followed by topical application of mitomycin, whereas 1 patient who failed to serial dilation needed open reconstructive procedure. Laser excision of the anterior subglottic web was performed in one patient. Another patient with underlying cerebral palsy could not be operated upon and was managed with tracheostomy.

CONCLUSION

Subglottic stenosis may be effectively man-aged with endoscopic surgical techniques, although the number of such sittings required varies with the type and severity of stenosis. Open surgical procedures need to be individualised as per the needs of the patient only after all the other endoscopic possibilities have been exhausted.

Balloon Laryngoplasty in Pediatric Population with Subglottic Stenosis: 5 Years Experience in King Abdulaziz University Hospital a Tertiary Center

We reviewed our experience with balloon laryngoplasty (BLP) as a primary management of SGS in a tertiary care center in Saudi Arabia. In this review, a total of 147 patients who underwent Laryngobronchoscopy were reviewed. Only 10 pediatric patients diagnosed with SGS who underwent BLP as primary treatment in the period from January 2012 to December 2017 were included. After obtaining ethical approval, included patients' charts were reviewed. Adult patients and those with airway anomalies other than SGS were excluded. This study describes the outcome of 25 episodes of BLP for the selected participants. Sixty percent of the participants were males. Participants' age ranged from 1 to 14 years (mean 6.4 years). Four participants had comorbidities other than SGS. Most patients required more than one episode of BLP (average 3 episodes). Mean hospital stay was 11.7 days. There was no difference in recurrence of symptoms between using laser or knife in subglottic tissue release (p = 0.182). Although recurrence of symptoms was seen in 56% of the patients, almost all patients (100%) became free of symptoms eventually. Patients with co-morbid diseases were more likely to be transferred to PICU post-operatively (p = 0.003). In the treatment of acquired SGS, BLP is an effective and relatively safe alternative to open airway surgery.

Subglottic injury: a clinically relevant animal model

OBJECTIVES/HYPOTHESIS

To develop a clinically aligned, reproducible model for subglottic injury.

STUDY DESIGN

Prospective randomized control pilot study.

METHODS

Juvenile (3-month-old) New Zealand White rabbits underwent intubation with a 3-cm length of an endotracheal tube that was chosen so that there would be no air leak below 20 cm of water. This tube was one or two sizes above the appropriate tube for the animal. It was held in situ with a suture placed at the trachea and secured over a button in the neck for a period of 1 week. Animals were sacrificed 1 week postextubation, and larynges were harvested. A range of histological techniques and gross morphology were utilized to examine the injury caused at the level of the subglottis. Unintubated animals constituted controlled specimens.

RESULTS

Intubated animals demonstrated considerable histopathology including evidence of ulceration, inflammation, granulation tissue, perichondritis, and chondritis when compared with control animals. Morphometric analysis demonstrated a significant increase in lamina propria thickness (P = .0013), mucosal thickness (P ≤ .0001), and in goblet cell areal density (P = .014). Analysis of mucin types found a significant decrease in acidic (P = .0001) mucin coinciding with a significant increase in mixed mucin types (P = .0013).

CONCLUSIONS

Our model provides a reliable and reproducible technique for acute/subacute injury to the subglottis secondary to intubation, which is consistent with previous histological findings of early changes associated with acquired subglottic stenosis (SGS). Future uses of this model could include the examination of current adjunctive therapies and their effects on limiting progression to SGS.

Short use of muscle relaxants following single stage laryngotracheoplasty in children

OBJECTIVE

The postoperative management of children undergoing single stage laryngotracheoplasty (SSLTP) includes intubation and muscle paralysis to secure the airway and protect the wound. We reduced the period of postoperative muscle paralysis in an attempt to decrease the incidence of pulmonary complications. The objective of this study was to evaluate the influence of the duration of muscle paralysis on pulmonary complications and outcome.

METHODS

Medical records of all children admitted, between 1994 and 2002, to the pediatric intensive care unit following SSLTP were analysed. Children were grouped according to the number of days muscle paralysis was used.

RESULTS

Thirty-six children (15 male, 21 female, mean age 32 months (9-162 months)) underwent SSLTP for laryngeal stenosis. Prior to surgery 29 needed a tracheotomy (mean duration 11.1 months). Shorter muscle paralysis leads to shorter intubation and mechanical ventilation and therefore PICU and hospital length of stay were 12.4 and 9.9days shorter in the group with short use of muscle paralysis (p<0.001 and p=0.002, respectively). There was no significant difference in postoperative complications, but a trend towards fewer atelectases in children with short muscle paralysis could be recognised. Postoperatively we observed no auto-extubations in either group and success rate of SSLTP was comparable in both groups (94 and 95%).

CONCLUSION

Children undergoing SSLTP can safely benefit from a postoperative strategy using a short duration of muscle relaxants. They have fewer days on mechanical ventilation with a concomitant decrease in duration of hospital stay.

Postoperative management of children after single-stage laryngotracheal reconstruction

OBJECTIVE

To report the safety and efficacy of a postoperative approach that avoids pharmacologic and physical restraints and allows liberal physical activity after single-stage laryngotracheal reconstruction in children.

DESIGN

Retrospective study.

SETTING

Tertiary care pediatric intensive care unit.

PATIENTS

One hundred thirty-three children who underwent single-stage laryngotracheal reconstruction, including laryngotracheoplasty, tracheal resection, and cricotracheal resection.

INTERVENTIONS

Five-year period of data collection regarding postoperative care and complications.

MEASUREMENTS AND MAIN RESULTS

The medical records of all patients (age range, 2-336 months; mean age +/- SEM, 66 +/- 5 months) who underwent single-stage laryngotracheoplasty, tracheal resection, or cricotracheal resection between 1993 and 1998 were reviewed. Tracheally intubated, awake, and unrestrained patients (group 1, n = 54; mean age, 113 +/- 8 months) were compared with tracheally intubated, sedated, and restrained patients (group 2, n = 79; mean age, 33 +/- 3 months). Pediatric intensive care unit length of stay was less in group 1 in comparison with group 2 patients (11.2 +/- 0.5 days vs. 13.7 +/- 0.6 days; p = .007). Hospital length of stay was less in group 1 than group 2 patients (16.7 +/- 1.0 days vs. 21.1 +/- 1.1 days; p = .01). Adverse events were fewer in group 1 compared with group 2 patients: atelectasis, 44% vs. 73% (p < .001); postextubation stridor, 22% vs. 53% (p < .001); and withdrawal syndromes, 0% vs. 43% (p < .001). The occurrence of pneumonia, airleak syndromes, unplanned extubation, and aspiration events was not different between groups.

CONCLUSIONS

For developmentally appropriate children, postoperative management after single-stage laryngotracheal reconstruction does not require the use of physical and pharmacologic restraints. Older children who are not sedated or restrained and who are allowed liberal physical activity have shorter pediatric intensive care unit and hospital lengths of stay, and a decreased incidence of postoperative adverse events. Centers performing single-stage laryngotracheal reconstruction should consider a postoperative management strategy that avoids sedatives, muscle relaxants, and physical restraints, and allows liberal bedside physical activity in developmentally appropriate children.

Assessment and management of laryngotracheal stenosis

Laryngotracheal stenosis should be suspected in children with recurrent, prolonged, or atypical croup; a history of endotracheal intubation; or a history of stridor, feeding difficulties, and failure to thrive. Tracheotomy-dependent patients with acquired laryngotracheal stenosis are candidates for surgical intervention to provide the child with the earliest opportunity to develop normal oral communication.

Laryngotracheal reconstruction for subglottic stenosis in children

The experience with laryngotracheal reconstruction in 20 children in Chicago is reviewed. Nine of the 20 children (45%) operated upon had congenital subglottic stenosis. Ten (50%) had acquired stenosis. One child was classified as having combined types. All patients underwent laryngotracheal reconstruction with autogenous costal cartilage grafts. Eight patients had both anterior and posterior costal cartilage grafts with stent insertion. One had a posterior costal cartilage graft only. Sixteen of the 20 children (80%) have been decannulated. Midtracheal or lower tracheal disease concomitant with laryngotracheal stenosis is an indication that endoscopic management of severe subglottic stenosis is likely to fail. Early laryngotracheal reconstruction is indicated for patients with a high likelihood of failure of endoscopic management and for those with severe cricoid cartilage deformities. Our results support the use of laryngotracheal reconstruction as an alternative to conservative (endoscopic) management of severe subglottic stenosis in carefully selected patients.

Subglottic stenosis in newborns after mechanical ventilation

Mechanical ventilation in the neonatal period is sometimes followed by difficulty in removal of the endotracheal tube although the patient does not need further respiratory support. This problem results from subglottic stenosis consequent on prolonged use of endotracheal tubes. We found this complication in 5 patients among 854 newborns who required artificial respiration. A further patient was admitted from another hospital because of extubation problems. Our clinical diagnosis was confirmed by endoscopy. Drug therapy with steroids and anti-inflammatory agents was tried in all six patients and was successful in two. In four patients conservative management failed and laser surgery was performed; three of these infants required tracheostomy. In two decannulation has already been performed at the age of 2 1/2 years.

IN CONCLUSION

five of six patients were treated successfully, and one 3-year-old patient is still being treated. In the light of reports from other authors, this approach can be recommended for the management of acquired subglottic stenosis.

Cricoid resection and thyrotracheal anastomosis in the growing primate

Although many procedures have been described for the correction of subglottic stenosis in the infant and child, none has been universally satisfactory. Cricoid resection and thyrotracheal anastomosis have been successful in adults, and we considered that the same techniques could be applied to correct subglottic stenosis in infants and children. A feasibility study was undertaken using young primates as a surgical model. The operation in each was accomplished uneventfully, although one animal later developed a complication possibly due to the use of a tissue adhesive. In practice, this complication could have been corrected without compromising the surgical outcome.

Laryngotracheal reconstruction in children. Five-year follow-up

Congenital and acquired subglottic stenosis is a commonly encountered problem in the pediatric population. In acquired cases endotracheal intubation is responsible for its development in the great majority of cases, but high tracheotomy, laryngeal burns, external neck trauma, and tumors, both intrinsic and extrinsic, are occasionally seen. The management of mature subglottic stenosis in children remains a controversial issue. The prevailing attitude of otolaryngologists is to perform a tracheotomy and hope for decannulation after one or two years, due to the expected growth of the larynx. Unfortunately, some of the acquired lesions are so severe that often no lumen is demonstrable. In such cases no amount of growth will allow extubation. A variety of endoscopic methods, such as dilation with or without resection using diathermy or laser, are certainly helpful in the early phases of wound healing while the scar tissue is soft and pliable. To deal with the mature, hard, fibrous, unresponsive scar various authors have proposed differing laryngotracheal reconstructive techniques. The authors discuss a unique experience of laryngotracheal reconstruction in 103 children. They define their indications for the three procedures that are most widely used, and address the issue raised by opponents of laryngotracheal reconstruction in children, namely the consideration that laryngeal growth potential may be adversely affected by such external operations. The authors have evidence that this has not occurred in 35 cases followed for a minimum of five years.

Laryngeal stenosis from endotracheal intubation. A review of 58 cases

During the decade of the 1970s, the Department of Otolaryngology at the Los Angeles County - University of Southern California Medical Center encountered 58 patients who requried tracheotomy for laryngeal stenosis secondary to endotracheal intubation. This included 19 children and 39 adults. We treated 50 of these patients, of whom 35 (70%) were decannulated after endoscopic management alone. One other patient could have been decannulated but needed the tracheotomy for medical reasons. Two other will probably be decannulated in the near future. Eight patients underwent open reconstructive procedures.

Laryngeal surgery in the pediatric patient

The primary concern in laryngeal surgery in the infant and child is to relieve airway obstruction, rather than phonation. Because airway obstruction above the larynx may stimulate or be confused with laryngeal pathology, these are described as the signs and symptoms of laryngeal disease. Although tracheotomy in the infant is frequently said to be a cause of a long-term problem, the procedure can be carried out in the smallest premature quite safely and without an extubation problem. The author's method of performing the operation is described. Most laryngeal surgery in the child is performed by the endoscopic approach, special scopes being used for special purposes. In addition to conventional instrumentation the cryoprobe and CO2 laser and employed. The author's method of treating glottic and subglottic stenosis is outlined.