Systematic Direct Laryngoscopy: The Lindholm Laryngoscopes

Deep learning-assisted 3D laser steering using an optofluidic laser scanner

Laser ablation is an effective treatment modality. However, current laser scanners suffer from laser defocusing when scanning targets at different depths in a 3D surgical scene. This study proposes a deep learning-assisted 3D laser steering strategy for minimally invasive surgery that eliminates laser defocusing, increases working distance, and extends scanning range. An optofluidic laser scanner is developed to conduct 3D laser steering. The optofluidic laser scanner has no mechanical moving components, enabling miniature size, lightweight, and low driving voltage. A deep learning-based monocular depth estimation method provides real-time target depth estimation so that the focal length of the laser scanner can be adjusted for laser focusing. Simulations and experiments indicate that the proposed method can significantly increase the working distance and maintain laser focusing while performing 2D laser steering, demonstrating the potential for application in minimally invasive surgery.

[Surgical treatment of laryngeal cysts in children with argonplasma coagulation]

Laryngeal diseases in young children are much less common than diseases of other ENT organs, which allows them to be attributed to the poorly studied section of pediatric otorhinolaryngology. This article presents the results of the examination and treatment of 37 children from different regions of the Russian Federation (aged 11 months to 3 years) with laryngeal cysts. The purpose of the study was to improve the results of surgical treatment for young children with laryngeal cysts.

A System for Characterizing Intraoperative Force Distribution During Operative Laryngoscopy

OBJECTIVE

This study aimed to create and validate an integrated data acquisition system for gauging the force distribution between a laryngoscope and soft-tissue during trans-oral surgery.

METHODS

Sixteen piezoresistive force sensors were interfaced to a laryngoscope and custom maxillary tooth guard. A protocol for calibrating the laryngoscope and maxilla sensors was developed using a motor-controlled linear stage and force measurements were validated against a digital scale. The system was initially tested during suspension laryngoscopy on three cadaver heads mounted on a cadaver head-holder. Intraoperative data was also collected from three patients undergoing head and neck tumor resection.

RESULTS

Mean calibration error of the scope sensors was less than 150 g (n = 3) and mean maxilla sensor error was less than 200 g (n = 3). Peak scope mag-forces of 8.09 ± 6.61 kg and peak maxilla forces of 7.62 ± 4.57 kg were experienced during the cadaver trials. The peak scope sensor mag-force recorded during the intraoperative cases was 24.7 ± 4.53 kg, and the peak maxilla force was 22.0 ± 4.60 kg.

CONCLUSION

The data acquisition system was successfully able to record intraoperative force distribution data. The usefulness of this technology in informing surgeons during trans-oral surgery should be further evaluated in patients with varying anatomic and procedural characteristics.

SIGNIFICANCE

Creation of a low-cost, integrated force-sensing system allows for the characterization of retraction forces at anatomic sites including the pharynx and larynx, brain, and abdomen. Real-time force detection provides surgeons with valuable intraoperative feedback and can be used to improve deformation models at various anatomic sites.

Tongue Edema Secondary to Suspension Laryngoscopy

OBJECTIVES

Suspension microlaryngoscopy (SML) is generally a safe, same-day procedure. Complications have been linked to prolonged operative time and substantial force applied to the tongue. This report of two cases describes marked tongue edema following SML, a complication not yet reported in the literature.

METHODS

This is a retrospective review of two cases of severe tongue edema following SML. We reviewed the literature for similar reports and proposed treatment plans.

RESULTS

Two patients, age 67 and 75, underwent SML for an interval of 247 minutes and 224 minutes for patient 1 and patient 2 respectively. Both developed severe tongue edema requiring inpatient monitoring and steroids. In both patients, the edema improved over several days and returned to baseline. There are no reported cases of this complication in the literature.

CONCLUSION

Prolonged SML can lead to tongue edema requiring close airway monitoring. The edema was self-limited and resolved with steroids and close monitoring.

"Hanger" in Intubation and Laryngoscopy

Achieving an adequate exposure in laryngoscopy is an extremely tedious task for the operating surgeon, especially for the anterior commissure lesions. Various maneuvers have been described to overcome this difficulty, but failed in providing an adequate exposure leading to a poor outcome. To create a device that can deliver uniform pressure over the laryngeal cartilage and succeed in providing an adequate exposure of the glottic lesion. A total of 44 patients were included in the study, divided into two groups containing 22 patients each. The distance at the level of anterior commissure from the superior border of the distal end of the laryngoscope was noted and compared. Group A subjected to digital cricoid pressure showed a mean distance of 9.09 of exposure with variance of 1.22 and Group B subjected to cricoid pressure with the cricoid catapult showed a mean distance of 11.76 with variance of 1.59. The groups were statistically analyzed using Anova Test and the test was found to be very significant (p < 0.0001). The catapult is made of a hanger defining its economics, which has a vital role in difficult intubations especially in anterior placed larynx, short neck and obese patients, also succeeds in providing an adequate exposure of the glottic lesion, (especially the anterior commissure) by delivering uniform pressure over the laryngeal cartilage, leading to a superior operative outcome.

Development of three-dimensional laryngostroboscopy for office-based laryngeal diagnostics and phonosurgical therapy

OBJECTIVE

To develop a three-dimensional (3D) laryngostroboscopic examination unit, compare the optic playback quality in relation to established 2D procedures, and report the first case series using 3D rigid laryngostroboscopy for diagnosis and management of laryngotracheal diseases.

STUDY DESIGN

Laboratory study, prospective case series.

METHODS

The optical efficacy of newly developed rigid 3D endoscopes was examined in a laboratory setting. Diagnostic suitability was investigated in 100 subjects (50 male, 50 female) receiving 2D high-definition (HD) and 3D laryngostroboscopy. Two of the subjects subsequently underwent 3D-assisted office-based transoral phonosurgery under local anesthesia. Main outcome measures were comparative visualization of laryngotracheal pathologies, influence on preoperative planning, and evaluation of prognostic factors for the outcome of phonosurgical interventions.

RESULTS

Three-dimensional endostroboscopic procedures were effectively optimized to establish an examination protocol for all-day clinical use. Office-based 3D laryngostroboscopy was successfully applied in subjects with normal anatomy (n = 10) and various laryngotracheal findings (n = 90). In comparison to 2D HD videolaryngostroboscopy, the 3D view offered enhanced visualization of laryngotracheal anatomy, with qualitatively improved depth perception and spatial representation. In organic pathologies, this resulted in a more precise indication of phonosurgical procedures, increased accuracy in surgical planning, facilitated office-based endoscopic surgery, and better evaluation of prognostic factors for the outcome of phonosurgical interventions.

CONCLUSION

Three-dimensional laryngostroboscopy proved to increase the understanding of functional and surgical anatomy. Its application has enormous potential for improving the diagnostic value of laryngoscopy, surgical precision in laryngotracheal interventions, tissue preservation, and methods of teaching.

LEVEL OF EVIDENCE

NA Laryngoscope, 128:2823-2831, 2018.

Reliability of office-based narrow-band imaging-guided flexible laryngoscopic tissue samplings

OBJECTIVES/HYPOTHESIS

Direct suspension laryngoscopic biopsy performed under general anesthesia is the conventional management for obtaining pathological diagnosis for neoplasms of the larynx, oropharynx, and hypopharynx. Since the development of distal chip laryngoscopy and digital imaging systems, transnasal flexible laryngoscopy tissue sampling has gained popularity as an office-based procedure. Additional assessment with narrow-band imaging (NBI) can help to increase the diagnostic yield. The aim of the study was to evaluate the accuracy, sensitivity, and specificity of a novel diagnostic tool: office-based NBI (OB-NBI) flexible laryngoscopic tissue sampling.

STUDY DESIGN

Retrospective chart review performed in a tertiary referral medical center in Taiwan.

METHODS

From January 2010 to February 2013, 90 consecutive patients received OB-NBI biopsies. The accuracies of the OB-NBI biopsies were compared among locations, tumor sizes, head and neck cancer histories, and other factors.

RESULTS

All patients had completed the procedure without life-threatening complications. The overall sensitivity and specificity were 97.2% and 100%, respectively, with a diagnostic accuracy of 98.9%. Accuracy was not affected by tumor size, location, learning curves, or previous head and neck cancer history.

CONCLUSIONS

We present an integrated technique that merges the safety and versatility of flexible laryngoscopy with the diagnostic power of NBI to produce a promising method of high accuracy and minimal morbidity.

LEVEL OF EVIDENCE

4 Laryngoscope, 126:2764-2769, 2016.

Spontaneous Ventilation Using Target-Controlled Propofol Infusion for Microlaryngoscopy in Adults: A Retrospective Audit

Summary

We conducted a retrospective audit of 285 adult elective microlaryngoscopy cases in our institution over a three-and-a-half year period. Conventional anaesthesia with intubation and mechanical ventilation was the most common technique, used in 71% of cases. Tubeless spontaneous ventilation during total intravenous anaesthesia with a target-controlled infusion of propofol (SVTCI) was the most common alternative. Spontaneous ventilation with target-controlled infusion was used for 79 (27.7%) anaesthetic inductions and was continued through the maintenance phase for 60 patients (21.1%). Jet and intermittent ventilation were both used infrequently (1% each). The most common SVTCI technique since 2013 involved adjusting the target-controlled infusion rate during induction using a formula we developed based on intermittently increasing the target rate, such that the predicted plasma concentration minus the predicted effect site concentration was maintained at 1 μg/ml. We found that this method maintained ventilation during induction more reliably than other SVTCI strategies, and was associated with fewer complications than other spontaneous ventilation techniques or mechanical ventilation: it was associated with only one (3.1%) failed induction and one (3.9%) episode of apnoea. Jet ventilation was associated with the most severe complications, including two cases of barotrauma.

Evaluation of the Dysphonic Patient (in: Function Preservation in Laryngeal Cancer)

The evaluation of the dysphonic patient begins with a complete understanding of the laryngeal anatomy and physiology of voice production. A thorough history must be taken regarding the dysphonia qualities, alarming symptoms, and confounding factors. The complete head and neck examination culminates in a detailed visualization of the vocal folds using image-capturing laryngoscopy as well as stroboscopy or high-speed digital imaging to fully evaluate the viscoelastic properties of the vocal fold cover-body structure and function. Finally, the evaluation leads to the biopsy of any concerning lesions either under magnification in the operating room or topical anesthesia in the office.

Suspension laryngoscopy for the thoracic surgeon: when and how to use it

Suspension laryngoscopy is one of the most common otolaryngological procedures for the diagnosis and surgical approach to the larynx. However, most thoracic surgeons are not familiar with the procedure and seldom use it. The indications for its use are similar to those for that of rigid bronchoscopy (dilatation, endoprosthesis insertion, and tumor resection). It can be performed in children and adults. Suspension laryngoscopy is an alternative when rigid bronchoscopy is unavailable and is therefore a viable option for use at smaller facilities. In this communication, we describe the technique and the applications of suspension laryngoscopy in thoracic surgery.

Improved airway visualization during direct laryngoscopy using self-retaining laryngeal retractors: a quantitative study

OBJECTIVE

To measure the degree to which the Lindholm laryngeal distending forceps improve visualization during direct laryngoscopy in selected pediatric patients.

STUDY DESIGN

Case series with chart review.

SETTING

Pediatric hospital.

SUBJECTS AND METHODS

Subjects included children undergoing direct laryngoscopy using the Lindholm laryngeal distending forceps. Intraoperative endoscopic photos with and without false cord retraction via the Lindholm laryngeal distending forceps were obtained from the Seattle Children's Hospital airway endoscopy photo library. Analysis was performed using imaging software. Comparisons of visible vocal cord and glottic opening areas as well as anterior commissure angles with and without the Lindholm laryngeal distending forceps were performed with a paired and unpaired Student t test.

RESULTS

The use of the Lindholm laryngeal distending forceps increased the glottic opening by a mean of 359% (95% confidence interval [CI], 255%-463%) and increased visualized true vocal cord area by 337% (197%-477%). Angle at the anterior commissure increased from a mean of 24.9° to a mean of 71.5°, resulting in a net mean angle increase of 46.6° (95% CI, 40.2°-52.9°). All measured changes were statistically significant with P values <.01.

CONCLUSIONS

When placed at the level of the false vocal folds, Lindholm laryngeal distending forceps will, at least in certain cases, greatly increase the visible area of the superior surface of the vocal folds, the anterior commissure, and, by increasing the glottic opening, the subglottic region. This improved visualization may enhance the surgeon's ability to diagnose and treat pathologies in these anatomic regions during direct laryngoscopy.

[Application of lasers in treatment of larynx diseases]

In otolaryngology, CO2 laser is the first and most commonly applied device. Such lasers as Ny:YAG generating visible light having wavelength 532 nm referred to as KTP laser due to the Name of the crystal where infrared light is converted to visible light. Such wavelenght, having green colour, due to strong absorption in haemoglobin is applied in treatments on tissues having dense blood vessels. The object of the work is to analyze larynx microsurgery laser treatments performer between 1994-2008 in the Otolaryngology Department of the Military Medical Institute CSK MON in Warsaw. The examination covered 445 patients including 142 women (31.9%) and 303 men (68.1%) aged between 12 and 80 (the average age of 48.2 year olds) who Were qualified in 1994-2003 for endoscopic laser surgery of the larynx. The operations field was watched using OPMI-11 operating microscope (Zeiss, Germany) allowing 4-16 times blow-up. Larynx laser microsurgery was performer using white laser beam: CO2 Illumina 40 (Heraeus LaserSonics, Germany) and green laser beam using KTP AURA XP laser (AMS, USA). The total of 445 larynx laser microsurgeries were performer. In recent years our clinic has seen an increase in the number of operations using this technique. The largest group were patients with recognized precancerous conditions (33.0%) and larynx carcinoma (26.4%). The next group in terms of the number of patients were 114 patients (20.6%) with recognized juvenile papilloma. Complications were observed in 180 patients. Table III show the type of recognized complications. The most commonly observed was swelling of the mucous membrane (48.3%), the rarest type was subcutaneous emphysema (3.3%). It was concluded that larynx laser microsurgery is a safe method and a valuable tool in treatment of larynx diseases, especially precancerous conditions and early forms of larynx carcinoma; that complications following procedure are relatively rare, usually mild, not life-threatening, and most often subsiding after a few days.

Emerging Concepts in Airway Infantile Hemangioma Assessment and Management

OBJECTIVE: The purpose of this study was to evaluate changes in airway infantile hemangioma treatment.

STUDY DESIGN: Retrospective.

SUBJECTS: Airway hemangioma patients, tertiary pediatric hospital.

METHODS: Data collected included age at diagnosis, evaluation methods, hospitalizations, airway size, and interventions. Patients were divided into group A (1981–1993) and group B (1994–2005) and were analyzed using descriptive statistics, the Fisher exact test, and the Student t test.

RESULTS: Thirty-two subjects were identified. Nasopharyngoscopy was used more in group B (11/16 [69%]) than group A (4/16 [25%], P = 0.032). CT angiography (3/16 [19%]) and laryngeal distractors (11/16 [69%]) were only used in group B; these techniques showed airway hemangiomas to be “transglottic,” not just “subglottic.” Intralesional steroids alone (3/16 [19%]) and primary hemangioma excision (2/16 [13%]) were new treatments used in group B. Frequent direct laryngoscopies (>six) correlated with tracheotomy (5/32 [16%], P = 0.015). Presenting age (<2 months) impacted treatment more than airway hemangioma size.

CONCLUSIONS: New methods of airway infantile hemangioma assessment changed our concept of airway hemangiomas and their primary treatment.

Laryngeal Complications of Endotracheal Intubation

An endotracheal tube placed in the larynx, even for a short time, causes at least superficial mucosal damage, an injury that normally heals readily. Long-term intubation, on the other hand, may cause pressure necrosis that can extend into submucosa, perichondrium, and eventually cartilage. The sites of involvement include the medial surface of the arytenoid cartilages, vocal processes, cricoarytenoid joints, posterior glottis, and subglottis. We review the pathogenesis, endoscopic recognition, classification, and progression of intubation injuries and examine the many variables that influence them. Diagrammatic flow charts trace the acute injuries through to their chronic sequelae, including subglottic stenosis, which is commoner in infants and children, and posterior glottic stenosis, which is commoner in adults. Systematic endoscopic assessment, under general anesthesia, using rigid telescopes to evaluate laryngeal damage during intubation is recommended and critically discussed. Endoscopy permits an informed judgment with regard to continuation of intubation. Depending on the severity and depth of ulceration, intubation can be continued (sometimes with a tube of smaller diameter) or tracheotomy performed, with an awareness of the attendant risks and benefits. Unnecessary tracheotomies may be avoided. Further, it may be possible to minimize untoward outcomes of prolonged intubation by using management techniques directed at known risk factors.