Airway stenosis: classification, pathogenesis, and clinical management

Airway stenosis (AS) is a fibroinflammatory disease characterized by abnormal activation of fibroblasts and excessive synthesis of extracellular matrix, which has puzzled many doctors despite its relatively low prevalence. Traditional treatment such as endoscopic surgery, open surgery, and adjuvant therapy have many disadvantages and are limited in the treatment of patients with recurrent AS. Therefore, it is urgent to reveal the pathogenesis of AS and accelerate its clinical transformation. Based on the discovered pathogenesis, including fibrosis, inflammation, epithelial-mesenchymal transition, metabolic reprogramming, microbiome, genetic susceptibility, and other mechanisms, researchers have developed a series of treatments, such as drug therapy, gene therapy, stem cell therapy, growth factor therapy, protein therapy, and photodynamic therapy. This review introduces the classification of AS, explores the existing pathogenesis and preclinical treatments developed based on the pathogenesis, and finally summarizes the current clinical management. In addition, the prospect of exploring the interaction between different types of cells and between microorganisms and cells to identify the intersection of multiple mechanisms based on single-cell RNA sequencing, 16S rRNA gene sequencing and shotgun metagenomic sequencing is worth looking forward to.

The safety and efficacy of spray cryotherapy after endoscopic sinus surgery in chronic rhinosinusitis: A systematic review of randomized controlled trials

BACKGROUND

Chronic rhinosinusitis (CRS) is a condition that affects 5-12% of the general population. Endoscopic sinus surgery (ESS) is the preferred treatment because of its few adverse effects and highest success rates. The most common post-operative consequences include synechia, nasal blockage, and disease recurrence. Spray cryotherapy is a novel therapeutic approach with promising outcomes for the treatment of upper airway disorders.This review aimed to investigate the effects of spray cryotherapy (SCT) following ESS in patients with chronic rhinosinusitis.

METHODS

Six electronic databases were searched for randomized clinical trials (RCTs). The selected trials were evaluated for methodological quality, and data were extracted by two independent reviewers. The Cochrane risk-of-bias tool was used to assess the quality of evidence.

RESULTS

Three RCTs with 85 patients were included in the final analysis. SCT was related to -16 and -77 reductions in Lund-McKay and SNOT-22 scores after 36 weeks of follow-up, in contrast to a placebo, which showed -10.4, -65. Regarding the side effects of SCT, no adverse effects were reported, and visual assessments showed no pain, visual field loss, or any other ocular complications.

CONCLUSIONS

SCT is a new treatment modality after endoscopic sinus surgery that shows an effective post-operative management strategy with better post-operative scales (Lund-McKay, SNOT-22, POSE, and Lund-Kennedy) and less edema, obstruction, crusting, and inflammation with minimal or no side effects. However, further research with longer follow-ups, a larger sample size, and subjective assessment is needed to assess any possible long-term side effects.

Cryotherapy for the Treatment of Tracheal Stenosis: A Systematic Review

Tracheal stenosis (TS) is an iatrogenic sequela after intubation or tracheostomy that is increasing despite technological improvement and skilled respiratory care in the ICU. According to the studies, the rate of TS varies from 10 to 22%, but only 1-2% of these stenoses are severe and present with inspiratory dyspnea that does not respond to medical management. Bronchoscopy is considered the most appropriate diagnostic test, and laser surgery and tracheobronchial stenting are the most commonly performed procedures for tracheal stenosis. However, alternative treatment options, including cryotherapy for inoperable patients, have yet to be studied widely. As the number of patients requiring ICU admission with mechanical intubation is increasing, it is crucial to acknowledge this complication and consider alternative management options. Here we present a review of the use of cryotherapy for post-intubation tracheal stenosis.  Pubmed, Cochrane, and EMBASE databases were inquired for studies performed using the keywords 'airway stricture' OR 'airway obstruction' AND 'post-intubation' OR 'post-extubation' OR 'tracheostomy' AND 'cryotherapy'. After the primary and secondary screening, five studies were included in the analysis.  We included 67 patients were included in the analysis, with a mean age of 50.2 (range: 42-55) years. Tracheal stenosis and subglottic stricture were the most common sites of stenosis. Twenty-nine patients were treated with cryotherapy only, while the rest 38 patients had cryotherapy followed by balloon dilation. After the intervention, 48 patients experienced improvement, five experienced no change in the symptoms, 13 patients were asymptomatic before the treatment, and one died. No complication was reported in 65 patients, with only minor complications reported in rest.  Although, there is no clear treatment protocol for patients with inoperable tracheal stenosis. Our review demonstrates that cryotherapy for inoperable tracheal stenosis can be an acceptable alternative treatment with significant clinical improvement. Additionally, cryotherapy has fewer adverse effects compared to other treatment options.

Comprehensive use of a high-frequency electric knife, balloon dilatation, and cryotherapy for tuberculous central tracheobronchial cicatricial constriction

BACKGROUND

To examine the benefits of interventional therapy for cicatricial constriction using a high-frequency electric knife, saccular dilatation, and cryotherapy.

METHODS

This case series included patients with central tracheobronchial cicatricial constriction admitted to the Department of Tuberculosis of Henan Provincial Chest Hospital from July 2018 to March 2021 and treated with bronchoscopic interventional therapies based on systemic anti-tuberculosis treatment.

RESULTS

96 patients were included, in whom 443 interventional therapies were performed. The total mid-(3 months) and long-term (12 months) effective rates were both 100%. The internal diameter of tracheobronchial stenosis increased after the operation, and the difference was statistically significant (all < 0.05). After interventional treatment, patients' symptoms of choking sensation in the chest and shortness of breath were relieved. Respiratory function was obviously improved. The ratios of hemorrhage, granulation hyperplasia, chest pain, and postoperative fever were 58.2%, 42.6%, 31.3%, and 26.7%, respectively. No focal transmission and progression of tuberculosis occurred, and no serious complications were observed.

CONCLUSION

The use of a high-frequency electric knife, saccular dilatation, and/or cryotherapy according to the pathological stage of the tracheobronchial cicatricial constriction is feasible, with good mid- and long-term curative effects and few complications.

Phonosurgery: A review of current methodologies

Cold-steel has served as the gold standard modality of phonosurgery for most of its history. Surgical laser technology has revolutionized this field with its wide use of applications. Additional modalities have also been introduced such as coagulative lasers, photodynamic therapy, and cryotherapy. This review will compare the surgical modalities of cold steel, surgical lasers, phototherapy and cryotherapy. The mechanism of action, tissue effects and typical uses will be addressed for each modality.

Protective effects of different anti‑inflammatory drugs on tracheal stenosis following injury and potential mechanisms

Tracheal stenosis following injury cannot be effectively treated. The current study compared the protective effects of different anti-inflammatory drugs on tracheal stenosis and investigated their possible mechanisms. Rabbit tracheal stenosis models following injury were constructed and confirmed using hematoxylin and eosin (H&E) staining. A total of 30 rabbits were divided into the control (CON), penicillin (PEN), erythromycin (ERY), budesonide (BUD) and PEN + ERY + BUD groups (n=6). Stenotic tracheal tissue, serum and bronchoalveolar lavage fluid (BALF) were collected 10 days after continuous treatment. Pathological changes in the tracheas were observed by H&E staining. Histone deacetylase 2 (HDAC2) expression in tracheal tissues was detected by immunofluorescence. Immunohistochemistry was performed to detect collagen I (Col-I) and collagen III (Col-III) levels in tracheal tissues. Transforming growth factor β1 (TGF-β1), vascular endothelial growth factor (VEGF) and interleukin 8 (IL-8) levels in serum and BALF samples were determined using ELISA kits. Western blotting detected HDAC2, IL-8, TGF-β1 and VEGF levels in tracheal tissues. H&E staining demonstrated that tracheal epithelial hyperplasia and fibroblast proliferation in the ERY and PEN + ERY + BUD groups markedly improved compared with the CON group. Furthermore, in tracheal tissues, HDAC2 expression was significantly increased and IL-8, TGF-β1, VEGF, Col-I and Col-III levels were significantly decreased in the ERY and PEN + ERY + BUD groups compared with the CON group. Additionally, the results for the PEN + ERY + BUD were more significant compared with the ERY group. In serum and BALF samples, IL-8, TGF-β1 and VEGF levels in the ERY and PEN + ERY + BUD groups were significantly lower compared with the CON group, with the results of the PEN + ERY + BUD group being more significant compared with the ERY group. There were no significant differences between the PEN, BUD and CON groups. ERY inhibited tracheal granulation tissue proliferation and improved tracheal stenosis following injury and synergistic effects with PEN and BUD further enhanced these protective effects. The mechanism may involve HDAC2 upregulation and inhibition of local airway and systemic inflammatory responses.

Successful management of subglottic stenosis in pregnancy

Evaluation and management of subglottic stenosis in pregnancy is challenging. It often is not only a multidisciplinary approach between obstetricians, otolaryngologists (ENT surgeons) and anesthesiologists, but also requires a thorough understanding of possible foreseen complications by the patient as well. Hence, whenever we are presented with a challenging case requiring multidisciplinary approach involving team of physicians from different specialties, it is routine practice to huddle regarding the preoperative, intraoperative and postoperative management and care. We present a case of a 37-year-old woman with a known history of idiopathic subglottic stenosis, 16 weeks' pregnant, G4P1, with a surgical history significant for two previous subglottic dilations in the past and who now presented with an audible stridor and shortness of breath on activity. We highlighted the unique challenges encountered and the corresponding management adopted. This is a case of successful management of symptomatic worsening of subglottic stenosis managed during pregnancy.

Subglottic Cryotherapy: A Pilot Study in New Zealand White Rabbits

To describe proof of concept and pilot data for a cryotherapy application in the subglottis in a rabbit airway model. Four New Zealand white rabbits (3 experimental, 1 control) underwent general anesthesia and laryngoscopy and bronchoscopy. Experimental animals had cryotherapy applied with a direct contact 1.9-mm cryoprobe. Animals were euthanized at days 0, 2, and 6 posttreatment. Histologic changes were assessed in the treated subglottic tissues. This preliminary work has demonstrated that, with early cryogenic injury in the subglottis, there is mild mucosal epithelial injury associated with submucosal edema, acute inflammatory infiltrate, and degeneration of venule endothelial cells. Mucosal epithelial repair and resolution of the inflammatory response appear to be relatively rapid. We hope that this may provide a foundation to further explore cryotherapy as a primary or adjuvant treatment option for pediatric subglottis stenosis.

Therapeutic Bronchoscopic Techniques Available to the Pulmonologist: Emerging Therapies in the Treatment of Peripheral Lung Lesions and Endobronchial Tumors

Therapeutic bronchoscopy for both endobronchial tumors and peripheral lung cancer is rapidly evolving. The expected increase in early stage lung cancer detection and significant improvement in near real-time imaging for diagnostic bronchoscopy has led to the development of bronchoscopy-delivered ablative technologies. Therapies targeting obstructing central airway tumors for palliation and as a method of local disease control, patient selection and patient-centered outcomes have been areas of ongoing research. This review focuses on patient selection when considering therapeutic bronchoscopy and new and developing technologies for endobronchial tumors and reviews the status of bronchoscopy-delivered ablative tools for peripheral lung cancers.

Maxillary Antrostomy Patency Following Intraoperative Use of Spray Cryotherapy

Objectives/Hypothesis: Stenosis of the middle meatus antrostomy (MMA) represents a major cause of recurrent disease following endoscopic sinus surgery (ESS). Various strategies have been developed to prevent the occurrence of MMA stenosis. The aim of the present study was to evaluate the effects of spray cryotherapy (SC) on nasal wound healing following ESS. Methods: This is a prospective within-subject, randomized, and controlled trial. Twenty-six patients submitted to bilateral ESS with chronic rhinosinusitis without polyps were included. Following surgery, patients were randomized to receive SC on one side and saline contralaterally. Outcomes were represented by MMA diameter and area, histology of nasal mucosa, and nasal symptoms. Variables were assessed at 3 and 12 months postoperatively. Results: The MMA size in the SC group at 3 and 12 months (area-0.578 ± 0.1025 cm², diameter-0.645 ± 0.1024 cm; 0.605 ± 0.1891 cm², 0.624 ± 0.0961 cm, respectively) was significantly larger (p = 0.000) than in the control group. Histology established that cell infiltration, goblet cells, edema, and epithelial hyperplasia were prominent and persistent in the control side compared to the SC side. Nasal obstruction and discharge were significantly improved in the SC group compared to the control group. Conclusion: SC is a promising therapy following ESS, since it precludes MMA stenosis and decreases inflammation, edema, and goblet cell hyperplasia.

Management of subglottic stenosis in pregnancy using advanced apnoeic ventilatory techniques

Objective

To describe the use of balloon dilation with non-invasive ventilation in the treatment of pregnant patients with idiopathic subglottic stenosis.

Methods

The medical charts of four consecutive patients who underwent jet ventilation or high-flow nasal cannula oxygenation with balloon dilation for the treatment of idiopathic subglottic stenosis during pregnancy were reviewed.

Results

Objective improvement of subglottic stenosis was seen in all four cases, with end-result Myer–Cotton grade 1 lesions down from pre-procedure grade 3 lesions. Patients also reported subjective improvements in symptomatology, with no further airway issues. All patients delivered normally, at term.

Conclusion

Laryngeal dilation with continuous radial expansion pulmonary balloons using non-invasive ventilation for the treatment of idiopathic subglottic stenosis in pregnant patients is safe and efficacious, and should be the first line treatment option for this patient population. The improvement in symptoms, and lack of labour and pregnancy complications, distinguish this method of treatment from others reported in the literature.

The effects of cryotherapy on vocal fold healing in a rabbit model

OBJECTIVES/HYPOTHESIS

Cryotherapy has been shown to be a scarless treatment modality for dermal lesions; however, there are limited data addressing the effect of cryotherapy on vocal fold tissue. The aim of this study was to clarify the effectiveness of cryotherapy for prevention of postsurgical vocal fold scarring.

STUDY DESIGN

Prospective animal study in rabbits.

METHODS

The lamina propria of 20 rabbit vocal folds was bilaterally stripped, followed by randomized unilateral cryotherapy. Five larynges were harvested for real-time polymerase chain reaction (RT-PCR) analysis at 1 day, 3 days, and 7 days postinjury. The remaining five were harvested for histologic analysis at 3 months. Images of the healing phase were recorded by laryngoscopy. Analyses of RT-PCR for cyclooxygenase (COX)-2, interleukin (IL)-6, collagen I, collagen III, matrix metallopeptidase 1 (MMP1), transforming growth factor β (TGFβ1), α smooth muscle actin (α-SMA), and hyaluronan synthase 1 (HAS1) were completed. Histological samples were completed for collagen and hyaluronic acid analysis.

RESULTS

RT-PCR results revealed that higher expressions of HAS1 and MMP1 and lower expressions of COX-2, IL-6, collagen I, collagen III, TGFβ1, and α-SMA were observed, and histological examination showed significantly increased hyaluronic acid, decreased deposition, and more organized configuration of collagen in injury with the cryotherapy cohort compared with the injury cohort.

CONCLUSIONS

Cryotherapy can inhibit the inflammatory reaction and simulate a fetal healing environment in extracellular matrix synthesis to regenerate vocal fold tissue with less fibrosis. Histological results showed that cryotherapy achieves a mature healing result with less scar, which tends to return to normal. In summary, the findings of this study suggest that administration of cryotherapy at the time of injury has the potential to minimize vocal fold scarring.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:E151-E157, 2019.

Cryotherapy has antifibrotic and regenerative effects on human vocal fold fibroblasts

OBJECTIVES/HYPOTHESIS

Vocal fold scarring remains a major treatment challenge, and scar prevention without residual lesions remains a dilemma. Cryotherapy has shown cosmetic outcomes on skin lesions with minimal scarring. The aim of this study was to clarify the beneficial effects of cryotherapy for the prevention and the treatment of vocal fold scarring.

STUDY DESIGN

In vitro.

METHODS

Primary cultures of human vocal fold fibroblasts (VFFs) were used in this study. Myofibroblast differentiation was stimulated by transforming growth factor β1 (TGF-β1). We mimicked the cryotherapy effect on vocal fold healing in vivo by freezing VFFs ± TGF-β1 in vitro. The influence of freezing on cell viability, proliferation, migration, and contractile properties were analyzed. The expression of collagen I, collagen III, fibronectin, TGF-β1, matrix metallopeptidase 1 (MMP1), hyaluronan synthase 1 (HAS1) were investigated by real-time polymerase chain reaction (RT-PCR), and the expression of alpha smooth muscle actin (α-SMA) and decorin were investigated by RT-PCR and Western blot.

RESULTS

Freezing was found to modify extracellular matrix (ECM) synthesis and differentiation of VFFs. Expression of collagen I, collagen III, fibronectin, α-SMA, and TGF-β1 was downregulated, and MMP1 was upregulated in VFFs + TGF-β1 (myofibroblast) by freezing. HAS1 and decorin were upregulated in both VFFs ± TGF-β1 by freezing. Freezing VFFs + TGF-β1 (myofibroblast) with fast thawing had a lower expression of α-SMA when compared with slow thawing. Freezing reduced the migration and collagen contraction of VFFs + TGF-β1 (myofibroblast).

CONCLUSION

Cryotherapy induces antifibrotic and regenerative ECM alterations in VFFs. These data provide insight into the prevention and the treatment of vocal fold scarring with cryotherapy in phonomicrosurgery.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:E143-E150, 2019.

Outcome of spray cryotherapy plus functional endoscopic sinus surgery on management of healing in nasal polyposis

BACKGROUND

Nasal Polyposis is a benign tumor in nasal or paranasal mucosa, which confronts difficulties in management of healing after treatments with surgery. The aim of this study was to evaluate the effects of Spray Cryotherapy (SCT) on management of healing in patients with nasal polyposis who undergone functional endoscopic sinus surgery.

METHODS

In this prospective, clinical trial study, we investigated on 40 patients with nasal polyposis that had indication for functional endoscopic sinus surgery. Patients were divided randomly into two parallel group; cryotherapy (with SCT) and placebo (without SCT). Evaluation of healing after surgery was evaluated with Lund-Mackay and The Sino-nasal outcome test (SNOT-22)-22 scores.

RESULT

Postoperatively, Lund-Mackay and SNOT-22 scores were significantly decreased in both groups, however these scores were significantly lower in cryotherapy group in comparison with placebo group. Also there were no reported serious side effects in both groups.

CONCLUSION

In this paper, we concluded that usage of SCT is an effective and safe method on management of healing and develops recovery rates in patients with nasal polyposis undergoing functional endoscopic sinus surgery.

N2 gas egress from patients' airways during LN2 spray cryotherapy

Spray cryotherapy using liquid nitrogen (LN₂) is a general surgical tool used to ablate benign or malignant lesions. Adequate egress of the gaseous nitrogen (N₂) generated during this process must be provided for safe use when LN₂ is used within the body rather than topically. When delivered to either the gastrointestinal tract (requiring active venting via a suction tube) or body cavities open to room barometric pressure (such as lung airways) allowing for passive venting, the N₂ gas generated from the boiling process must be evacuated. This work will examine the egress of N₂ during procedures requiring passive venting from human airways undergoing liquid nitrogen spray cryotherapy. Venting characteristics for safe N₂ egress will be presented and discussed based on analytical modeling using fluid mechanics simulations and experimental studies of N₂ venting with laboratory and porcine models.

Metered Cryospray™: a novel uniform, controlled, and consistent in vivo application of liquid nitrogen cryogenic spray

In this article, a novel cryotherapy approach using a uniform, controlled, and consistent in vivo application of liquid nitrogen (LN₂) spray as a Metered Cryospray^™ (MCS) process is described. Although MCS may be used for many potential clinical applications, this paper focuses on the development that led to the controlled and consistent delivery of radial LN₂ cryogen spray in order to generate a uniform circumferential effect and how the amount of MCS can be adapted to specifically ablate targeted diseases within a patient’s lumen such as an airway or esophagus.

Current status of spray cryotherapy for airway disease

The use of liquid nitrogen to treat skin and mucosal lesions is well understood in the dermatologic and gastrointestinal literature. Direct spray cryotherapy (SCT) in the airway has shown promising results in the treatment of esophageal premalignant and even invasive lesions. In the airway, several studies have shown it to be a safe, effective treatment for both benign and malignant disease. It is easily administered in the outpatient setting and can be repeated several times without undue side effects. In this article, we review the current literature on the use of SCT for the treatment of endobronchial lesions and also describe our own institutional experience of the use of SCT in the airway. The use of proper technique and airway venting is important in mitigating the complications of barotrauma from massive expansion of nitrogen upon conversion from the liquid to gaseous state. We also review some of the basic science principals behind the use of the cryotherapy to treat lesions in different tissues. We feel that SCT is a potential area for further research at both clinical and basic science level.

Cryotherapy for Treatment of Mouth Mucocele

A mucocele is a common salivary gland disorder that most commonly affects young adults. A 35-year-old female patient reported to the Department of Oral and Maxillofacial Surgery, with the chief complaint of swelling on the left side of floor of mouth. The aim of this case report is to present the management of mucocele present in floor of the mouth in a young female patient using liquid nitrogen cryosurgery. The present case report has also discussed mechanism of action, current protocol of cryosurgery with emphasis on clinical pros and cons along with the clinical outcomes.

Idiopathic Subglottic and Tracheal Stenosis

Objectives:

To report and compare patients’ experiences with acquired subglottic stenosis (AS) versus idiopathic subglottic and tracheal stenosis (ISTS).

Methods:

A survey was made available to patients with AS and ISTS. Results were analyzed for inter- and intragroup differences using a 2-tailed t test.

Results:

The study included 160 survey participants (AS n = 28; ISTS n = 132), with a predominance of female participants (82% AS, 98% ISTS). Acid reflux was the most prevalent comorbidity across groups (42%-43%). A significant difference in time to diagnosis was found between groups, with 32% of AS patients diagnosed within 3 months of symptom onset, compared to 2% with ISTS. A diagnosis delay greater than 18 months occurred for 58% of ISTS patients. There was no difference in treatment approach, with the most common treatment being balloon dilation, followed by laser dilation. Tracheal resection was performed in 36% of patients in both groups. Patient satisfaction with surgical outcomes was significantly higher after tracheal resection (76%) compared to other treatment modalities (39%).

Conclusions:

ISTS remains a diagnostic challenge as highlighted by the delay in diagnosis compared to AS. There appears to be no historical or symptomatic factors specific to ISTS. Additionally, patients report increased satisfaction and symptom resolution after tracheal resection.

The influence of spray cryotherapy on wound healing following endoscopic sinus surgery in chronic rhinosinusitis

OBJECTIVES/HYPOTHESIS

The aim of this study was to assess the influence of spray cryotherapy on wound healing following endoscopic sinus surgery (ESS).

STUDY DESIGN

A prospective, randomized, double-blinded, controlled trial.

METHODS

The study included 22 consecutive adult patients with chronic rhinosinusitis with and without polyps scheduled for bilateral ESS. At the end of the surgical procedure, patients were randomized to the distribution of spray cryotherapy in one middle meatus and saline contralaterally. Outcomes were only measured for endoscopy scores. Thus, postoperative healing and the amount of edema, crusting, secretions, and scarring were assessed using the validated Lund-Kennedy and Perioperative Sinus Endoscopy (POSE) scores.

RESULTS

There were no baseline differences concerning POSE and Lund-Kennedy scores between the two groups. Nevertheless, a significant difference was recorded at one, 2, 4, 8, and 12 weeks in both POSE (P = .001, P = .012, P = .02, P = .006, P = .001) and Lund-Kennedy (P = .002, P = .005, P = .02, P = .02, P = .03) scores.

CONCLUSIONS

These preliminary results reveal an improvement in postoperative scores, demonstrating enhanced healing following spray cryotherapy. However, without patient subjective outcomes, the study is limited. Additional studies with longer follow-up and larger samples are needed to describe the effects of cryotherapy on wound healing.

The Use of Cryotherapy for Papilloma and Early Laryngeal Cancers: Long-term Results

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

To determine the efficacy of adjuvant cryotherapy in the treatment of early glottic cancer and laryngeal papillomatosis.

SUMMARY OF BACKGROUND DATA

The use of cryotherapy in conjunction with traditional modalities has recently been proposed to improve voice outcomes in patients with early laryngeal cancer as compared to pretreatment conditions. This study investigates its utility in improving oncological outcomes and decreasing recurrences of laryngeal papillomatosis.

METHODS

Patients with either early glottic cancer or laryngeal papillomatosis that received cryotherapy as part of their surgical regimen were investigated. All patients were seen at a large tertiary care center within a 10-year window. Demographic data were collected and all postoperative notes were reviewed. Recurrences of the laryngeal cancer were noted, as was the duration of time between successive papillomatosis operations.

RESULTS

The charts of 54 glottic cancer and 29 papillomatosis patients that received cryotherapy were reviewed. One patient from the papillomatosis cohort was excluded from statistical analysis due to lack of follow-up. Overall, 16 (30%) of the laryngeal cancer patient experienced a malignant recurrence. The overall 5-year survival of these patients was 98% and the 5-year disease-free survival was 74%. The use of adjuvant cryotherapy in the treatment of laryngeal papillomatosis extended the duration of time between surgeries by an average of 79 days (P=.23).

CONCLUSION

The use of adjuvant cryotherapy in the treatment of early glottic cancer does not improve the rate of carcinoma recurrences. Additionally, cryotherapy does not result in a statistically significant increase in the duration of disease-free period for laryngeal papillomatosis patients, although the observed increase may be clinically important.

Effects of cryotherapy on the maxillary antrostomy patency in a rabbit model of chronic rhinosinusitis

It is acknowledged that many causes of failures in endoscopic sinus surgery are related to scarring and narrowing of the maxillary antrostomy. We assessed the effect of low-pressure spray cryotherapy in preventing the maxillary antrostomy stenosis in a chronic rhinosinusitis (CRS) rabbit model. A controlled, randomized, double-blind study was conducted on 22 New Zealand rabbits. After inducing unilateral rhinogenic CRS, a maxillary antrostomy was performed and spray cryotherapy was employed on randomly selected 12 rabbits, while saline solution was applied to the control group (n = 10). The antrostomy dimensions and the histological scores were assessed 4 weeks postoperatively. The diameter of cryotreated antrostomy was significantly larger at 4 weeks than that in the control group. At 4 weeks, the maxillary antrostomy area in the study group was significantly larger than the mean area in the control group (103.92 ± 30.39 mm² versus 61.62 ± 28.35 mm², P = 0.002). Submucosal fibrous tissues and leukocytic infiltration in saline-treated ostia were more prominent than those in cryotreated ostia with no significant differences between the two groups regarding the histological scores. Intraoperative low-pressure spray cryotherapy increases the patency of the maxillary antrostomy at 4 weeks postoperatively with no important local side effects.

Endoscopic spray cryotherapy for genitourinary malignancies: safety and efficacy in a porcine model

OBJECTIVE

To examine the effects and safety of using endoscopic spray cryotherapy (ESC) on bladder, ureteral, and renal pelvis urothelium in a live porcine model.

SUBJECTS AND METHODS

ESC treatments were systematically applied to urothelial sites in the bladder, ureter, and renal pelvis of eight female Yorkshire swine in a prospective trial. Freeze-thaw cycles ranged from 5 to 60 s/cycle for one to six cycles using a 7 French cryotherapy catheter. Tissue was evaluated histologically for treatment-related effects. Acute physiologic effects were evaluated with pulse oximetry, Doppler sonography, and postmortem findings.

RESULTS

In bladder, treatment depth was inconsistent regardless of dose, demonstrating urothelial necrosis in one, muscularis propria depth necrosis in two, and full thickness necrosis in all remaining samples. In ureter, full thickness necrosis was seen in all samples, even with the shortest spray duration (5 s/cycle for six cycles or 30 s/cycle for one cycle). Treatment to the renal pelvis was complicated by adiabatic gas expansion of liquid nitrogen to its gaseous state, resulting in high intraluminal pressures requiring venting to avoid organ perforation, even at the lowest treatment settings. At a planned dose of 5 s/cycle for six cycles of the first renal pelvis animal, treatment was interrupted by sudden and unrecoverable cardiopulmonary failure after three cycles. Repeated studies replicated this event. Ultrasound and immediate necropsy confirmed the creation of a large gaseous embolism and reproducible cardiopulmonary effects.

CONCLUSION

ESC in a porcine urothelial treatment model results in full-thickness tissue necrosis in bladder, ureter, and renal pelvis at a minimal treatment settings of 5 s/cycle for six cycles. Adiabatic gas expansion may result in fatal pyelovenous gas embolism and collateral organ injury, as seen in both animals receiving treatment to the renal pelvis in this study. These results raise safety concerns for use of ESC as a treatment modality in urothelial tissues with current device settings.

Primary dilatation as a treatment for pediatric laryngotracheal stenosis: a systematic review

OBJECTIVE

To identify and review original studies on balloon and rigid dilatation as primary therapy for laryngotracheal stenosis (LTS) in pediatric patients.

DESIGN

Systematic review.

METHODS

A comprehensive search strategy in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials was conducted and limited to human studies published in English after 1980. Two independent reviewers identified original studies on primary dilatation therapy for LTS in patients younger than 18 years. Studies on tracheobronchial stenosis or stents for tracheomalacia were excluded. 22 of 369 identified studies (6%) met the inclusion criteria. Two reviewers independently appraised the level of evidence of each study, using the Oxford clinical evidence-based medicine guidelines, and extracted raw data using a standardized form developed a priori.

RESULTS

The patient population consisted of grades I-III LTS. Most studies used adjuvant therapy including laser or topical agents. The primary outcome of success was achieving a functional airway without open laryngo-tracheal surgery or ongoing need for a tracheostomy. In studies using balloon dilatation alone (6 studies, n=10) or rigid dilatation alone (5 studies, n=68), success rates were 50% and 53%, respectively. Success rates ranged from 50% to 78% for balloon dilatation with adjuvant therapy (6 studies, n=24) and 53%-100% for rigid dilatation with adjuvant therapy (5 studies, n=61).

CONCLUSIONS

Dilatation was successful as primary therapy in the majority of low-grade pediatric LTS. Given the lack of comparative studies among other study limitations, it could not be determined whether one method of dilatation was superior to another.

Spray cryotherapy is effective for bronchoscopic, endoscopic and open ablation of thoracic tissues

OBJECTIVES

Spray cryotherapy (SCT) delivers a liquid nitrogen spray via a catheter to produce cellular death. This study seeks to determine the histological changes after bronchoscopic, endoscopic and open SCT on tissues in the thoracic cavity.

METHODS

Yorkshire pigs underwent flexible bronchoscopy, endoscopy and thoracotomy for SCT of the airway, oesophagus and other intrathoracic structures, respectively. Variations in the duration and number of spray cycles for the same dosimetry were compared.

RESULTS

Bronchoscopic SCT of the airway resulted in cellular death up to the cartilage layer. Endoscopic SCT of the oesophagus led to cell death up to the adventitial layer. Tissue necrosis was severe in the lung, of full thickness in the pleura, but very superficial in the great vessels. The extracellular matrix (ECM) of treated tissues remained well-preserved. Having shorter but more cycles of SCT decreased the depth of the cellular necrosis. One pig developed ventricular fibrillation during the surgery and expired.

CONCLUSIONS

SCT causes reproducible tissue injury with the preserved ECM of most tissues within the thoracic cavity, making it enticing for ablation around vital structures like the great vessels with a decreased long-term risk. Further study is warranted to investigate the adverse events during SCT.

Cryotherapy for Barrett's esophagus and esophageal cancer

PURPOSE OF REVIEW

To summarize the recent literature on endoscopic spray cryotherapy for the treatment of Barrett's esophagus and esophageal cancer.

RECENT FINDINGS

Endoscopic spray cryotherapy is a relatively new ablative modality for the treatment of gastrointestinal diseases. Spray cryotherapy rapidly cools tissues by spraying them with either liquid nitrogen or rapidly expanding carbon dioxide gas. Initial, nonrandomized and uncontrolled studies show success rates comparable to other ablative modalities for the treatment of Barrett's esophagus with high-grade dysplasia, with complete eradication of dysplasia seen in 87-96% and complete eradication of intestinal metaplasia in 57-96% of treated patients. In early-stage esophageal cancer, spray cryotherapy appears to have a unique role, eliminating mucosal cancer in 75% of patients, including those who have failed other modalities. Patient tolerance of the procedure is very good. Limitations of current studies include small sample sizes and short durations of follow-up, and further studies are needed to validate the promising early results.

SUMMARY

Endoscopic spray cryotherapy is a promising ablative modality for treatment of Barrett's esophagus and esophageal cancer.

Endoscopic spray cryotherapy for esophageal cancer: safety and efficacy

BACKGROUND

Few options exist for patients with localized esophageal cancer ineligible for conventional therapies. Endoscopic spray cryotherapy with low-pressure liquid nitrogen has demonstrated efficacy in this setting in early studies.

OBJECTIVE

To assess the safety and efficacy of cryotherapy in esophageal carcinoma.

DESIGN

Multicenter, retrospective cohort study.

SETTING

Ten academic and community medical centers between 2006 and 2009.

PATIENTS

Subjects with esophageal carcinoma in whom conventional therapy failed and those who refused or were ineligible for conventional therapy.

INTERVENTIONS

Cryotherapy with follow-up biopsies. Treatment was complete when tumor eradication was confirmed by biopsy or when treatment was halted because of tumor progression, patient preference, or comorbid condition.

MAIN OUTCOME MEASUREMENTS

Complete eradication of luminal cancer and adverse events.

RESULTS

Seventy-nine subjects (median age 76 years, 81% male, 94% with adenocarcinoma) were treated. Tumor stage included T1-60, T2-16, and T3/4-3. Mean tumor length was 4.0 cm (range 1-15 cm). Previous treatment including endoscopic resection, photodynamic therapy, esophagectomy, chemotherapy, and radiation therapy failed in 53 subjects (67%). Forty-nine completed treatment. Complete response of intraluminal disease was seen in 31 of 49 subjects (61.2%), including 18 of 24 (75%) with mucosal cancer. Mean (standard deviation) length of follow-up after treatment was 10.6 (8.4) months overall and 11.5 (2.8) months for T1 disease. No serious adverse events were reported. Benign stricture developed in 10 (13%), with esophageal narrowing from previous endoscopic resection, radiotherapy, or photodynamic therapy noted in 9 of 10 subjects.

LIMITATIONS

Retrospective study design, short follow-up.

CONCLUSIONS

Spray cryotherapy is safe and well tolerated for esophageal cancer. Short-term results suggest that it is effective in those who could not receive conventional treatment, especially for those with mucosal cancer.