3D Models in the Diagnosis of Subglottic Airway Stenosis

Brazilian airway surgery survey indicates low overall numbers and need for improved teaching skills

OBJECTIVES

The Brazilian Society of Thoracic Surgeons conducted an online survey to determine the number of surgeons that perform adult and paediatric airway surgery and to understand the practice patterns along the country.

METHODS

Active members were electronically invited to complete the questionnaire through the REDCapR platform. Invitations were sent from January to April 2020. The survey encompassed 40 questions that explored 4 different topics in the assessment of tracheal diseases: (i) surgeon's demography; (ii) institutional profile, (iii) education and training in laryngo-tracheal surgery and (iv) preoperative and postoperative evaluation.

RESULTS

Eighty-nine percentage of the responders declared to perform tracheal surgery with a median of 5 tracheal resection procedures per year [interquartile range (IQR) 3-12]. Interaction with other specialties occurs in 37.3% of cases. Access to technology and devices is highly variable across the country. Resident training in airway surgery consists in traditional lectures in 97% of the cases. Training in animals (15.2%), cadavers (12.1%) and simulators (6.1%) are rare. Preoperatory evaluation encompasses flexible bronchoscopy (97.8%) and/or computed tomography (CT) scan of the airways (90.6%). Swallowing (20.1%) and voice (14.4%) disorders are rarely evaluated. Eighty-nine percentage of the surgeons consider bronchoscopy to be the preoperatory gold-standard exam, followed by CT scan (38.8%) and CT-3D reconstruction (37.4%).

CONCLUSIONS

Brazilian surgeons refer that airway resection and reconstruction are part of their current practice, but the total number of procedures per surgeon per year is low. Access to high-end technology and equipment is heterogenous. Training offered to residents in most academic institutions relies on traditional lectures.

3D Printed Larynx as a Novel Simulation Tool for Window Elaboration in Medialization Laryngoplasty

OBJECTIVE

Surgical simulation training in residents has declined due to the limited exposure to cadaveric specimens. Three-dimensional (3D)-printing technology is rapidly taking an important role in different medical areas, especially in surgical specialties. It provides an alternative for resident simulation practices and for developing surgical skills before exposure to real settings. The elaboration of the thyroid window in the medialization laryngoplasty procedure requires high technical precision and experience for better outcomes.

METHODS

The computer-based 3D reconstruction model was created using computed tomograph scan images from a standard larynx. The final model was created using a deposition modeling 3D printing technique with polylactic acid filament. The model was tested for surgical simulation practice in three otolaryngology residency programs in Bogotá, Colombia.

RESULTS

The model had similar anatomic detail and it was considered very useful, safe, and relevant for surgical simulation.

CONCLUSIONS

3D printed models are a cost-effective alternative for resident training.

Anatomic evaluation of Pancoast tumors using three-dimensional models for surgical strategy development

OBJECTIVE

Pancoast tumor resection planning requires precise interpretation of 2-dimensional images. We hypothesized that patient-specific 3-dimensional reconstructions, providing intuitive views of anatomy, would enable superior anatomic assessment.

METHODS

Cross-sectional images from 9 patients with representative Pancoast tumors, selected from an institutional database, were randomly assigned to presentation as 2-dimensional images, 3-dimensional virtual reconstruction, or 3-dimensional physical reconstruction. Thoracic surgeons (n = 15) completed questionnaires on the tumor extent and a zone-based algorithmic surgical approach for each patient. Responses were compared with surgical pathology, documented surgical approach, and the optimal "zone-specific" approach. A 5-point Likert scale assessed participants' opinions regarding data presentation and potential benefits of patient-specific 3-dimensional models.

RESULTS

Identification of tumor invasion of segmented neurovascular structures was more accurate with 3-dimensional physical reconstruction (2-dimensional 65.56%, 3-dimensional virtual reconstruction 58.52%, 3-dimensional physical reconstruction 87.50%, P < .001); there was no difference for unsegmented structures. Classification of assessed zonal invasion was better with 3-dimensional physical reconstruction (2-dimensional 67.41%, 3-dimensional virtual reconstruction 77.04%, 3-dimensional physical reconstruction 86.67%; P = .001). However, selected surgical approaches were often discordant from documented (2-dimensional 23.81%, 3-dimensional virtual reconstruction 42.86%, 3-dimensional physical reconstruction 45.24%, P = .084) and "zone-specific" approaches (2-dimensional 33.33%, 3-dimensional virtual reconstruction 42.86%, 3-dimensional physical reconstruction 45.24%, P = .501). All surgeons agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction benefit surgical planning. Most surgeons (14/15) agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction would facilitate patient and interdisciplinary communication. Finally, most surgeons (14/15) agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction's benefits outweighed potential delays in care for model construction.

CONCLUSIONS

Although a consistent effect on surgical strategy was not identified, patient-specific 3-dimensional Pancoast tumor models provided accurate and user-friendly overviews of critical thoracic structures with perceived benefits for surgeons' clinical practices.

Imaging in neonatal respiratory disease

The purpose of this review is to describe the current state of the art in clinical imaging for NICU patients, divided into major areas that correspond to likely phenotypes of neonatal respiratory disease: airway abnormalities, parenchymal disease, and pulmonary vascular disease. All common imaging modalities (ultrasound, X-ray, CT, and MRI) are discussed, with an emphasis on modalities that are most relevant to the individual underlying aspects of disease. Some promising aspects of dynamic and functional imaging are included, where there may be future clinical applicability.

Systematic review and meta-analysis of 3D-printing in otolaryngology education

INTRODUCTION

Three-dimensional (3D) printing has received increased attention in recent years and has many applications. In the field of otolaryngology surgery, 3D-printed models have shown potential educational value and a high fidelity to actual tissues. This provides an opportunity for trainees to gain additional exposure, especially as conventional educational tools, such as cadavers, are expensive and in limited supply. The purpose of this study was to perform a meta-analysis of the uses of 3D-printing in otolaryngology education. The primary outcomes of investigation were surgical utility, anatomical similarity, and educational value of 3D-printed models. Secondary outcomes of interest included country of implementation, 3D-printer materials and costs, types of surgical simulators, and the levels of training of participants.

METHODS

MEDLINE, Embase, Web of Science, Google Scholar and previous reviews were searched from inception until June 2021 for eligible articles. Title, abstract, and data extraction were performed in duplicate. Data were analyzed using random-effects models. The National Institute of Health Quality Assessment Tool was used to rate the quality of the evidence.

RESULTS

A total of 570 abstracts were identified and screened by 2 independent reviewers. Of the 274 articles reviewed in full text, 46 articles met the study criteria and were included in the meta-analysis. Surgical skill utility was reported in 42 studies (563 participants) and had a high degree of acceptance (84.8%, 95% CI: 81.1%-88.4%). The anatomical similarity was reported in 39 studies (484 participants) and was received positively at 80.6% (95% CI: 77.0%-84.2%). Educational value was described in 36 studies (93 participants) and had the highest approval rating by participants at 90.04% (87.20%-92.88%). A subgroup analysis by year of publication demonstrated that studies published after 2015 had higher ratings across all outcomes compared to those published prior to 2015.

CONCLUSION

This study found that 3D-printing interventions in otolaryngology demonstrated surgical, anatomical, and educational value. In addition, the approval ratings of 3D-printed models indicate a positive trend over time. Future educational programs may consider implementing 3D-printing on a larger scale within the medical curriculum to enhance exposure to otolaryngology.

Development of a cadaveric head and neck cancer model and three-dimensional analysis of margins in surgical navigation-aided ablations

INTRODUCTION

The adequacy of the surgical resection is the main controllable variable that is in the hands of the surgical team. There exists an unmet need to increase the rate of negative margins, particularly in cancers invading the craniofacial area. The study aimed 1) at developing a gross tumor model to be utilized for research, educational, and training purposes and 2) establishing the 3-dimensional relationship between the outer surface of the surgical specimen and tumor surface and test the effect of guiding ablations on cadavers with surgical navigation (SN).

MATERIAL AND METHODS

Seven cadaver heads were employed to create 24 craniofacial tumor models. Simulation of tumor resections was performed by 8 surgeons. Fourteen and 10 resections were performed with and without SN-guidance, respectively. Gross specimens underwent computed tomography and 3-dimensional analysis through dedicated software. Task load was assessed through a validated questionnaire. Tumor model reliability was studied based on visual analogue scale rate by surgeons and radiologists.

RESULTS

SN reduced the rate of margin involvement, particularly by decreasing the percentage of the gross specimen outer surface involvement in areas uncovered by normal bony structures. The workload of SN-aided ablations was found to be medium-to-somewhat-high. Tumor model reliability was deemed satisfactory except for the extension to bony structures.

CONCLUSIONS

A gross tumor model for head and neck cancers involving the craniofacial area was developed and resulted satisfactorily reliable from both a surgical and radiologic standpoint. SN reduced the rate of margin involvement, particularly by improving delineation of bone-uncovered areas.

Central airway issues in bronchopulmonary dysplasia

While there is a very large focus on the abnormalities of parenchymal lung development and extensive efforts to minimize alveolar damage with "gentle ventilation" and noninvasive respiratory support for neonates with bronchopulmonary dysplasia (BPD), there is relatively little consideration for the implications of central airway disease in this patient population. There are significant changes in the structure and conformation of the central airway during the last half of gestation, and premature birth disrupts this natural developmental process. The arrest of maturation results in a smaller airway that is more compliant, easier to deform, and more susceptible to damage. Consequently, neonates with BPD are prone to developing central airway pathology, particularly for patients who require intubation and positive pressure ventilation. Central airway disease can be divided into dynamic and fixed airway obstruction and results in increased respiratory morbidity in neonates with chronic lung disease of prematurity.

Three-dimensional printing in otolaryngology education: a systematic review

PURPOSE

The progressive expansion of the technology that facilitates the development of three-dimensional (3D) printing within the field of otorhinolaryngology has opened up a new study front in medicine. The objective of this study is to systematically review scientific publications describing the development of 3D models having applications in otorhinolaryngology, with emphasis on subareas with a large number of publications, as well as the countries in which the publications are concentrated.

METHODS

In this literature review, specific criteria were used to search for publications on 3D models. The review considered articles published in English on the development of 3D models to teach otorhinolaryngology. The studies with presurgical purposes or without validation of the task by surgeons were excluded from this review.

RESULTS

This review considered 39 articles published in 10 countries between 2012 and 2021. The works published prior to 2012 were not considered as per the inclusion criteria for the research. Among the 39 simulators selected for review, otology models comprised a total of 15 publications (38%); they were followed by rhinology, with 12 (31%); laryngology, with 8 (21%); and head and neck surgery, with 4 publications (10%).

CONCLUSION

The use of 3D technology and printing is well established in the context of surgical education and simulation models. The importance of developing new technological tools to enhance 3D printing and the current limitations in obtaining appropriate animal and cadaver models signify the necessity of investing more in 3D models.

Preliminary Experience With a Novel Metallic Segmented Transcordal Stent Modified With Three-Dimensional Printing for Inoperable Malignant Laryngotracheal Stenosis

Background

This study aims to assess the feasibility of a novel metallic segmented transcordal stent modified with three-dimensional (3D) printing for treating inoperable malignant laryngotracheal stenosis and the tolerability of the stent.

Methods

This was a retrospective study. The stents were individually customized with the aid of 3D printing model based on the anatomic features of each patient’s airway. The stent was composed of two separate segments that corresponded to the larynx and the upper trachea. The stents were barrel-shaped at the proximal end to prevent migration. The proximal end of the stent was located slightly above the vocal cord. The technical and clinical success of stenting procedure, patient tolerability, and stent-related complications of patients were evaluated.

Results

Ten patients with dyspnea caused by malignant laryngotracheal stenosis underwent implantation of such stents. Technical and clinical success of the stenting procedure were achieved in all patients. For all patients, basic communication in life could be maintained by speaking softly. During follow-up, one patient showed intolerance to the stent, and the stent was retrieved 2 weeks after stenting. Stent migration was found in one patient, and the position of the stent was readjusted. Granulation tissue proliferation was found in two patients and was treated with cryotherapy by bronchoscopy. There were no deaths associated with stenting.

Conclusions

The individually customized metallic segmented transcordal stent is feasible and tolerable for patients with inoperable malignant laryngotracheal stenosis. The implantation of this stent may serve as a novel alternative treatment for patients who are not suitable for surgery or tracheotomy.

Customization of stent design for treating malignant airway stenosis with the aid of three-dimensional printing

Background

The treatment of malignant stenosis involving the carina or bronchi is challenging due to complicated anatomy with individual variation, which makes it necessary to customize stents for each patient. Therefore, this study aims to evaluate the feasibility of a novel metallic segmented airway stent customized with the aid of three-dimensional (3D) printing for such cases.

Methods

The stents were individually customized with the aid of a 3D printed mold based on computed tomography (CT) images according to the anatomical features of the airway. A segmented design was applied on the junction part of the main stem and the branches to fit the dynamic changes of the carina angle. In 12 patients with airway stenosis caused by malignancies including esophageal cancer (EC) and lung cancer (LC), the stents were implanted. The technical and clinical success of the stenting procedure, Hugh-Jones (HJ) classification, Karnofsky performance status (KPS), and stent-related complications of patients were evaluated.

Results

The stenting procedure was technically successful in all patients, and 11 patients showed significant palliation of dyspnea after stenting. The HJ and KPS classification of patients after stent insertion improved significantly compared with those before stenting (P=0.003 and P=0.006, respectively). During follow-up, granulation tissue proliferation and sputum retention were found in two and four patients, respectively.

Conclusions

This study shows that the implantation of a novel stent designed with the aid of 3D printing is feasible for relieving dyspnea and improving performance status of patients with inoperable malignant stenosis involving the carina or bronchi.

Surgery for laryngotracheal stenosis: Improved results

OBJECTIVE

Laryngotracheal resection is still considered a challenging operation and few high-volume institutions have reported large series of patients in this setting. During the 5 years, novel surgical techniques as well as new trends in the intra- and postoperative management have been proposed. We present results of our increased experience with laryngotracheal resection for benign stenosis.

METHODS

Between 1991 and May 2019, 228 consecutive patients underwent laryngotracheal resection for subglottic stenosis. One hundred eighty-three (80.3%) were postintubation, and 45 (19.7%) were idiopathic. Most of them (58.7%) underwent surgery during the past 5 years. At the time of surgery, 139 patients (61%) had received tracheostomy, laser, or laser plus stenting. The upper limit of the stenosis ranged between actual involvement of the vocal cords to 1.5 cm from the glottis.

RESULTS

There was no perioperative mortality. Two hundred twenty-two patients underwent resection and anastomosis according to the Pearson technique; 6 patients with involvement of thyroid cartilage underwent resection and reconstruction with the laryngofissure technique. Airway resection length ranged between 1.5 and 8 cm (mean, 3.8 ± 0.8 cm) and it was >4.5 cm in 19 patients. Airway complication rate was 7.8%. Overall success of airway complication treatment was 83.3%. Definitive success was achieved in 98.7% of patients. Patients presenting with idiopathic stenosis or postcoma patients showed no increased failure rate.

CONCLUSIONS

Laryngotracheal resection for benign subglottic stenosis is safe and effective, and provides a very high rate of success. Careful intra- and postoperative management is crucial for a successful outcome.

Functional outcome after single-stage laryngotracheal reconstruction with rib cartilage grafting

OBJECTIVE

Single-stage laryngotracheal reconstruction (SSLTR) provides a definite surgical treatment for patients with complex glotto-subglottic stenosis. To date, the influence of SSLTR on the functional outcome after surgery has not been analyzed.

METHODS

A retrospective analysis of all patients receiving a SSLTR between November 2012 and October 2019 was performed. Preoperatively and 3 months postoperatively, patients received a full functional evaluation, including spirometry; voice measurements (eg, fundamental frequency; dynamic range, singing voice range, and perceptual voice evaluation using the Roughness-Breathiness-Hoarseness [RBH] score, and fiberoptic endoscopic evaluation of swallowing [FEES]).

RESULTS

A total of 15 patients with a mean age of 45 ± 17 years underwent SSTLR. Two (13%) patients were men and 13 (87%) were women. The majority of patients (67%) had undergone previous surgical or endoscopic treatment attempts that had failed. At the 3-month follow-up visit, none of the patients had signs of penetration or aspiration in their swallowing examination. Voice measurements revealed a significantly lower fundamental voice frequency (201.0 Hz vs 155.5 Hz; P = .006), whereas voice range (19.1 semitones vs 14.9 semitones; P = .200) and dynamic range (52.5 dB vs 53.0 dB; P = .777) was hardly affected. The median RBH score changed from R1 B0 H1 to R2 B1 H2. In spirometry, breathing capacity increased significantly (peak expiratory flow, 44% vs 87% [P < .001] and mean expiratory flow at 75% of vital capacity, 48% vs 90% [P < .001]). During a median follow-up of 32.5 months (range, 7-88 months), none of the patients developed re-stenosis.

CONCLUSIONS

For complex glotto-subglottic stenoses, durable long-term airway patency together with reasonable voice quality and normal deglutition can be achieved by SSLTR.