Safe and successful management of difficult tracheal intubations (DTIs) remains a significant challenge due to anatomical variability, patient comorbidities, and operator-dependent factors. While video laryngoscopy (VL) has improved first-attempt success rates, failures still occur in 11% to 45% of cases,1–4 with ultimate failure rates between 5.2% and 7.3%.5
The primary aim of this prospective observational study was to evaluate efficacy of the use of a novel, handheld, image-guided robotic intubation system Spiro-VISTA (Spiro Robotics, Inc) designed to enhance precision, control and procedural success in patients with difficult airways.
METHODS
The trial was conducted at Kaunas Hospital of the Lithuanian University of Health Sciences from October to November 2024, with written informed consent obtained from all patients. The study was approved by the local Institutional Ethics Committee and the Lithuanian Ministry of Health, was prospectively registered with the European Database on Medical Devices (EUDAMED, registration number CIV-LT-24-08-048614), and adhered to Good Clinical Practice (GCP) and STROBE guidelines (https://www.strobe-statement.org).
The trial included 30 adult patients (ASA physical status 1-3) with anticipated difficult airways presenting for elective surgery. The inclusion criteria required at least one predictor of difficult direct or video laryngoscopy based on standard airway assessment tests, a history of difficult intubation, BMI ≥ 35 kg/m², large neck circumference (NC), or specific independent predictors of difficult VL, including head and neck cancer diagnosis, neck pathology (a mass, a scar, radiation changes), short thyromental (TMD) distance, NC:TMD ratio of ≥ 5, a simplified Arné score ≥ 11 (Supplemental Digital Content, Table S1, http://links.lww.com/AA/F399), and others.1,2,6–9 Awake intubation was performed at the operator’s discretion; such patients, and those with advanced cardiovascular or pulmonary disease, were excluded. The anesthetic protocol and study procedures were standardized for all patients. All patients were orotracheally intubated by study investigators (A.K., D.B., J.B., and L.K.) using Spiro-VISTA™ (Video Intubation System for Total Access), which integrates dual VL and video bronchoscopy guidance with the joystick-controlled, precision robotic (servo-operated) intubation interface (Figure and Video 1).
Figure.
Spiro-VISTA essential components, controls and assembly. Spiro-VISTA is an investigational airway device not yet cleared or approved for commercial use by the FDA or other regulatory bodies. Spiro-VISTA™ integrates video laryngoscopy (VL) and a robotic (servo-operated), disposable flexible intubation scope (FIS), controlled by an operator using a joystick and buttons embedded in a specialized 2-channel disposable endoscopy blade. The system currently supports standard endotracheal tubes (ETT) from 5.0 to 7.5 mm ID. Fully assembled spiro-VISTA (A) and its key components (A and B): 1—A reusable handheld unit with integrated VL baton and servo controls. 2—A reusable video cable connecting Spiro-VISTA to Spiro’s split-screen monitor (not shown). 3—A disposable, robotic FIS that attaches to the servo control section of the handheld unit. 4—A 2-channel disposable blade with manual FIS controls (highlighted in blue circle), including a joystick and advancement buttons. When the blade is attached, its controls automatically interface with the servo control section of the handheld unit. 5—A standard endotracheal tube (ETT) preloaded over FIS and positioned within the right channel of the blade. The left channel accommodates the VL baton. C, Close-up view of the distal dual-video camera section of Spiro-VISTA. The intubation is observed and controlled fully from above and below the vocal cords using video laryngoscopy (VL) and the flexible intubation scope (FIS) cameras. The VL camera (right) and FIS camera (left) are positioned side by side at the distal end of the 2-channel disposable blade. When the blade tip is engaged either in the vallecula or beneath the epiglottis, both cameras are optimally placed near the larynx, enabling precise, servo-controlled FIS navigation into the trachea. The wire reinforced ETT in the FIS channel is depicted for demonstration purposes only.
Table.
Patients’ Preoperative Airway Assessment and Spiro-Vista’s Intubation Performance
| Characteristic | Value (n = 30) |
|---|---|
| History predictive of anticipated difficult airway | |
| History of difficult laryngoscopy or intubationa | 1 (3.3) |
| Pathologies associated with difficult intubationb | 7 (23.3) |
| Symptoms of airway pathologyb | 15 (50.0) |
| Moderate-to-severe obstructive sleep apneac | 11 (36.7) |
| Planned ENT surgerya | 12 (40.0) |
| ENT head and neck cancer diagnosisa | 5 (16.7) |
| Predictors of anticipated difficult airway | |
| Mallampati class 3 or 4 | 21 (70.0) |
| Thyromental distance (TMD) < 6.5 cma | 5 (16.7) |
| Inter-incisor gap < 3.5 cma | 2 (6.7) |
| Limited mandibular protrusiond | 9 (30.0) |
| Neck motion of 90° or lessa | 6 (20.0) |
| Presence of a neck massa | 3 (10.0) |
| Presence of a neck surgical scara | 4 (13.3) |
| BMI ≥ 35 (kg/m2) | 16 (53.3) |
| Obesity Class 2 (35 ≤BMI < 40) 9 (30.0) | |
| Obesity Class 3 (BMI ≥ 40) 7 (23.3) | |
| Large neck circumference (NC)e | 21 (70.0) |
| Ratio of NC to TMD ≥ 5a | 21 (70.0) |
| Arné score ≥ 11a | 14 (46.7) |
| Total number of predictors of difficult laryngoscopy per patient | 5 (3.3-7) |
| Difficult direct laryngoscopy | 3 (1.3-4.0) |
| Difficult video laryngoscopy | 2 (1.0-3.8) |
| Patients with predictors of difficult direct laryngoscopy | 29 (96.7) |
| 1 predictor | 7 (23.3) |
| 2–3 predictors | 13 (43.3) |
| 4–5 predictors | 9 (30.0) |
| ≥ 6 predictors | 0 (0.0) |
| Patients with predictors of difficult video laryngoscopy | 25 (83.3) |
| 1 predictor | 8 (26.7) |
| 2–3 predictors | 9 (30.0) |
| 4–5 predictors | 7 (23.3) |
| ≥ 6 predictors | 1 (3.3) |
| Spiro-VISTA intubation performance | |
| First pass success rate (FPS) | 30/30 (100.0) [95% CI: 88.4%–100%] |
| Adverse events or complications | 0/30 (0.0) [95% CI: 0%–11.6%] |
| Intubation time (sec) | 55 (45–71) |
| Lowest SpO2 during intubation (%) | 98 (±2.4) |
| Lowest SpO2 after intubation (%) | 97 (±5.3) |
| External laryngeal manipulation | 0 (0.0) |
| Laryngeal view 1/2a/2b/3/4/ | 12/17/1/0/0 |
| Intubation force (VAS 1-100)f | 10 (5.0–15.0) |
| Intubation ease of use (VAS 1-100)f | 6 (3.0–11.5) |
Values are presented as numbers (%), means (±SD), or medians (IQR).
Independent predictors of difficult video laryngoscopy.
(part of Arné score) Tumors of the upper and/or lower airway, facial deformities, or malformation(s); acromegaly; cervical spine (C-spine) disease (osteoarthritis, spondylosis, rheumatoid arthritis, etc.) or cervical spine precautions or instrumentation associated with limitation of neck movements; long-term diabetes mellitus with “stiff joint” syndrome; Stridor, dyspnea, dysphonia, dysphagia.
Documented in the chart, by polysomnography, or by preoperative STOP-BANG score ≥ 3.
Inability to move the lower teeth in front of the upper teeth.
>38 cm in females and >40 cm in males.
VAS: visual analog scales (0–100) reflecting operator’s subjective assessment of the usability of the device, with “0” indicating best performance (minimum intubation force and maximum ease of use).
Confidence intervals for FPS and adverse events/complications were determined using Clopper-Pearson exact method.
The primary outcome was the first-attempt intubation success rate. Secondary outcomes included the incidence of adverse events and complications (moderate hypoxemia [SpO2 < 85%], esophageal intubation, trivial mucosal trauma, dental injury, and pharyngeal/laryngeal/tracheal injury), as well as the intubation time, laryngeal view, and operator-reported subjective assessments of intubation force and ease of use of Spiro-VISTA. The force and ease of use were measured on the visual analog scales (VAS; 0–100), with lower values indicating better performance. No formal hypothesis testing was conducted in this first-in-human observational trial.
RESULTS
The study results are presented in the Table. First-attempt intubation success was 100%, with no adverse events or complications. Median intubation time was 55 seconds. The study cohort exhibited high airway complexity, with BMI ≥ 35 kg/m2 (53.3%), moderate-to-severe obstructive sleep apnea (36.7%), preoperative airway pathology symptoms (50%), high NC:TMD ratio of ≥5 (70%), Arné score ≥11 (46.7%) and a median of 5 predictors of intubation difficulty per patient, consisting of 3 for difficult DL and 2 for difficult VL. Cormack-Lehane grade 1 or 2a views were achieved in 29 out of 30 patients, without the need for external laryngeal manipulation. Per operators’ subjective assessment, intubation with Spiro-VISTA was described as requiring minimal force and being very easy to perform. No significant differences in intubation time or force were observed among operators.
DISCUSSION
This study represents the first successful clinical evaluation of a novel, image-guided robotic intubation system that integrates advanced airway visualization with precision-guided navigation for managing difficult airways. The study results suggest a high procedural success rate and a favorable safety profile for Spiro-VISTA in this prospective observational trial.
The 100% first-attempt intubation success observed with Spiro-VISTA may be attributed to full airway visualization afforded by dual VL and FIS cameras, precision robotic FIS navigation facilitated by the proximity of the FIS camera to the glottic opening, and full operator control of intubation both above and below the vocal cords. Additionally, indwelling FIS facilitates ETT advancement, with immediate confirmation of proper ETT placement. A video demonstrating Spiro-VISTA intubation of the study patient with recurrent laryngeal cancer and post-radiation glottic stenosis highlights the advanced features of the device (Video 2).
The consistency in intubation time across operators suggests comparable procedural efficiency, which was not affected by the number of predictors of intubation difficulty. The Cormack-Lehane grade 1 and 2a views were achieved with Spiro-VISTA in 40% and 56.7% of patients, consistent with other studies reporting a predominance of favorable laryngeal views in cases where VL intubation nevertheless remained challenging.2,7 It may also reflect the versatility of the Spiro-VISTA dual endoscopy blade, which effectively engages both above and below the epiglottis.
Although this study did not include a direct VL comparative group, a review of the literature suggests that Spiro-VISTA’s success rates and procedural efficiency are within or exceeding reported VL benchmarks. Other studies report VL first-attempt success rate of <70% in comparable patient cohorts.2,3 The operation of Spiro-VISTA conceptually aligns with the dual video intubation (DVI) technique when VL and FIS are used simultaneously by 2 operators. DVI has been reported to increase first-attempt intubation success rates by nearly 40% and reduce DTI-related complications by over 90% compared to the use of VL alone.2 However, this technique requires the immediate availability of 2 separate devices and 2 trained operators, which limits its practicality in many clinical settings.2 Spiro-VISTA™ has been designed as a single-operator, on-demand platform with integrated visualization, precision-controlled navigation, and an intuitive interface, which may offer workflow advantages over DVI in DTI settings and further reduce operator variability. The development of Spiro-VISTA also aligns with the growing paradigm shift toward advancing robotic-assisted technologies in airway management.10
In summary, the study results suggest a high procedural success rate and no adverse events during use of the Spiro-VISTA in this prospective observational trial. Unlike traditional video laryngoscopes, Spiro-VISTA integrates advanced image guidance with precision robotic control, representing a novel approach to difficult airway management. To the best of our knowledge, no other intubation devices currently offer this type of functionality.11 Further clinical evaluation of Spiro-VISTA’s efficacy and safety is warranted in larger trials, including its comparison with established DTI techniques, such as VL and FIS.
ACKNOWLEDGMENTS
The authors thank Dr Andrius Macas for his support in coordinating the logistics of the study.
DISCLOSURES
Conflicts of Interest: V. Nekhendzy is the founder of Spiro Robotics, Inc., holds equity in the company, and serves as a paid consultant to the company. This study was sponsored by Spiro Robotics, Inc. The other authors were supported by Spiro Robotics, Inc., for their role in conducting the study. No other authors declared conflicts of interest. Funding: This study was funded by Spiro Robotics, Inc., which developed the investigational device (Spiro-VISTA) used in this study. The sponsor had no role in the study design, study conduct, or data collection. This manuscript was handled by: Narasimhan Jagannathan, MD, MBA.
ASSOCIATED VIDEO
The video can be accessed at https://journals.lww.com/cases-anesthesia-analgesia/10.1213/ANE.0000000000007658
Video 1. The Flexible Intubation Scope (FIS) articulates 360 degrees and advances with robotic precision, enabling controlled robotic navigation through the airway. The operator maneuvers the FIS using a joystick and buttons, which interface seamlessly with the servo control system, allowing for intuitive, fine-tuned, and responsive control adjustments during intubation. Video courtesy Spiro Robotics, Inc.
Video 2. Spiro-VISTA™ is inserted similarly to traditional video laryngoscopy (VL) devices. With the tip of the blade placed either above or below the epiglottis, the VL and flexible intubation scope (FIS) cameras are positioned side by side near the vocal cords. This dual-camera setup simplifies the identification of anatomical landmarks for more accurate and controlled airway management. The FIS controlled navigation of the airway complements the VL’s panoramic view with real-time, dynamic and detailed airway imaging. High-resolution video feeds from both cameras are displayed side by side on Spiro’s split-screen monitor, allowing the operator to maintain full control of intubation all the way into the trachea. Once the FIS reaches the tracheal carina, the operator advances the preloaded ETT, instantly confirming its tracheal placement through direct visualization. Spiro-VISTA™ is then removed, and ETT positioning is further verified using standard methods. Video courtesy Spiro Robotics, Inc.
Supplementary Material
Footnotes
Conflicts of Interest, Funding: Please see DISCLOSURES at the end of this article.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website.
Clinical Trial Registration: The study was prospectively registered with the European Database on Medical Devices (EUDAMED, registration number CIV-LT-24-08-048614).
Reprints will not be available from the authors.
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