- Email: [email protected]
Improved Glottic Exposure for Robotic Microlaryngeal Surgery: A Case Series
ARTICLE IN PRESS Improved Glottic Exposure for Robotic Microlaryngeal Surgery: A Case Series *Dehra A. McGuire, †Jennifer P. Rodney, and †Nilesh R. Vasan, *†Oklahoma City, Oklahoma Summary: Robotic surgery has become the standard of care for many procedures outside of otolaryngology and now is gaining momentum within our specialty. The da Vinci (Intuitive Surgical, Sunnyvale, CA) robot has several advantages to human hands, including removal of tremor and better access to lesions because of increased degree of movement of the articulated instruments. The glottis has rarely been addressed using robotic surgery because access was previously thought to be difficult because of the limitations of currently used retractors, which include poor base of tongue and oral commissure retraction resulting in lack of exposure of the glottis in many patients and lack of space for the robotic instruments to occupy. We present a case series using the Modular Oral Retractor (MOR) system to show that the glottic larynx can be accessed by the da Vinci instrumentation. The MOR system provides better exposure of the anterior commissure and by using oral commissure retraction provides excellent space for the robotic arms to work. The MOR system potentially makes robotic microlaryngeal surgery more feasible for the otolaryngology-head and neck surgeon. Key Words: Modular oral retractor–Transoral robotic surgery–Robotic microlaryngeal surgery–Supraglottic surgery–Laryngeal surgery. INTRODUCTION Robotic surgery is quickly gaining traction in many areas of surgery because of the many benefits it provides over traditional methods. It eliminates human tremor and can be less invasive than open procedures, often resulting in decreased hospital stay and faster recovery.1,2 The larynx has remained a difficult anatomical area to address with robotic surgery. Transoral robotic surgery has steadily been gaining ground in otolaryngology, specifically for oropharyngeal and supraglottic resections for both benign and malignant neoplasms as well as sleep-disordered breathing. However, the larynx has remained a difficult area to address via robotic surgery, being limited by poor visualization of the larynx as well as the size and space requirements of the robotic arms. A small number of studies have assessed the potential of robotic microlaryngeal surgery (RMLS), all using Accepted for publication January 26, 2017. Financial support: This case report did not require financial support. However, the authors do have an Intuitive Surgical, Inc. Clinical Research Grant to continue to perform and present research using the MOR system. Conflict of interests: Nilesh Vasan is the inventor of the retractor described in this case report, with an International Patent application for the device filed in 2013 through the University of Oklahoma. Jennifer Rodney and Dehra McGuire do not have any conflicts of interest to disclose. This manuscript was presented at the Triological Society Combined Sections in Coronado Island, California, USA, January 22–24, 2015, and at The Voice Foundation Symposium in Philadelphia, Pennsylvania, USA, June 1–5, 2016. Informed consent was obtained from the participants included in the study. Additional informed consent was obtained from the participant for whom identifying information is included in this article. Consent to publish: Written consent to publish has been obtained from the participant to report individual patient data. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors. From the *University of Oklahoma College of Medicine, Oklahoma City, Oklahoma; and the †Department of Otorhinolaryngology, University of Oklahoma, Oklahoma City, Oklahoma. Address correspondence and reprint requests to Dehra McGuire, The University of Oklahoma, College of Medicine, Health Sciences Center, 800 Stanton L. Young Blvd, suite 1400, Oklahoma City, OK 73104. E-mail: [email protected] Journal of Voice, Vol. ■■, No. ■■, pp. ■■-■■ 0892-1997 © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jvoice.2017.01.014
different methods of exposure. A recurring theme during these investigations is that multiple instruments have to be used to obtain access to the glottis, and space for the robotic instruments is limited.3–5 Traditional microlaryngeal surgery is limited to direct laryngoscopes, which do not allow 360° access to glottic lesions. Twenty-five-centimeter-long instruments are introduced through the laryngoscope to reach the vocal folds, magnifying the surgeon’s tremor. The procedure is analogous to an attempt to write fine cursive by holding on to the distal end of a 25-cm-long pen. Visualization is limited to the small view provided through the laryngoscope using a microscope. Several retractors have been used in RMLS including the FeyhKastenbauer, Laryngeal Advanced Retractor System, and Dingman retractors. A common theme in the literature is the armamentarium of robotic retractors often provides inadequate access to the glottis, especially in the area of the anterior commissure because of poor tongue retraction. Oral commissure retraction has also been reported to be insufficient.3–10 We had previously proposed a device called the Modular Oral Retractor (MOR) system that is able to easily obtain a view of the glottis with the robot and maximize space in the glottic region to allow the robotic arms to function (see Figure 1). The device potentially enables RMLS to be performed. It provides improved oral commissure and tongue base retraction, allowing room for the robotic arms to work and excellent anterior commissure exposure. The face frame is open to allow more space for the robotic arms to move during a procedure. The MOR system eliminates the need for a rigid laryngoscope, which narrows the visual field, increases the distance of the working view to the surgical site, and serves as an obstacle around which robotic arms have to work. The 360° axis of rotation at the juncture of the base of the blade and the inferior portion of the mouth retractor allows superb exposure of the entire glottis, which may eliminate the need for a tongue suture, potentially decreasing incidence of tongue edema, airway complications, and postoperative patient discomfort. The axis of rotation at the base of the blade optimizes elevation of the tongue and allows for retraction of the tongue down to the vallecula, an option not available
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Case #1 A 56-year-old man with a long history of smoking initially presented with progressive hoarseness and dysphagia for 8 months and underwent direct laryngoscopy and biopsy at an outside facility, which showed squamous hyperplasia of the bilateral true vocal folds and diffuse, severe supraglottic hypertrophy. Nasopharyngoscopy performed in our clinic revealed redundant supraglottic mucosa that prolapsed into the glottic airway with associated plicae ventricularis, retroflexed epiglottis, and prolapsed aryepiglottic folds. It was not possible to view the glottis because of the redundant mucosa. The remainder of the head and neck examination was unremarkable. The patient was deemed a good candidate for robotic-assisted surgery using the MOR system. Informed consent was obtained for examination of the larynx and removal of the obstructing mucosa with a CO2 laser. He consented for use of the MOR system under an institutional review board (IRB)-approved protocol.
FIGURE 1. The Modular Oral Retractor (MOR) system with a removable tongue blade that allows for anterior and posterior advancement. with other retractors. The maxillary brace also has a 360° axis of rotation that further augments the ability of the retractor to push the tongue and the epiglottis forward, allowing visualization of the glottis. The MOR system includes 15 different blades that are interchangeable based on each patient’s unique anatomy to provide an optimal view of the glottis (Figure 2). We present a case series of three patients, which further demonstrates the ease with which the MOR retractor can facilitate visualization and access to the glottic area.
FIGURE 2. The different blades available to use with the MOR system.
Procedure After general anesthesia was induced and a shoulder roll was inserted, the MOR was inserted into the oral cavity using an appropriate curved blade and was suspended using the MOR suspension block. The retractor gave excellent access to the larynx (see Figure 3). The tongue blade used was a curved type that was inserted into the vallecular space. There are multiple blade types available with the MOR system that takes into account the differences in anatomy between patients. When initially inserting the retractor using a headlight, the curve of the tongue blade provided elevation of the epiglottis, which exposed the arytenoid mucosa. In some patients, more of the glottic larynx may be seen and these patients are easier candidates for robotic surgery. Following docking of the robot, the entire glottis including the anterior vocal folds could be visualized with the 30° upward directed scope, but more importantly, accessed by the robotic arms (see Figure 4). Ultrafine microlaryngeal procedures cannot be
FIGURE 3. The MOR system in place demonstrating the access available to the supraglottic and glottic regions of the throat for surgery.
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of supraglottic tissue, including using a laryngoscope with dysplastic biopsies negative for malignancy. Follow-up Six months postoperatively, the patient was diagnosed with laryngeal squamous cell carcinoma and underwent total laryngectomy. He had no recurrence of malignancy at 18month follow-up status post laryngectomy.
FIGURE 4. The MOR system with robotic arms in place for surgery. satisfactorily performed with Intuitive Surgical instrumentation as these instruments were primarily designed for the abdomen. The improved exposure eliminated the need for a retraction tongue suture. The robot is docked with a Maryland dissector to the left and a needle driver on the right that allows mobilization and use of the OmniGuide CO2 laser (Lexington, MA). Setup using the retractor was relatively simple. The redundant mucosa on the superior aspect of the arytenoid cartilage on the left was excised completely using the laser at 15 watts. Unlike access obtained during microlaryngoscopy with a superiorto-inferior orientation within a narrow scope, tissue could be excised using the laser in a side-to-side manner, which is impossible with microlaryngoscopy. The MOR system therefore allows multiple surgical orientation options at the target tissue level. Hemostasis was achieved with the laser and suction cautery. A similar procedure was performed on the left side. The interarytenoid area was not treated to avoid contracture. The redundant mucosa was easily mobilized with the Maryland forceps (see Figure 5). Because the patient had generalized edema, we elected to ablate the false cord on the left side, which was prominent. There were no complications during the procedure. The patient was monitored closely and had undergone multiple debridements
Case #2 A 79-year-old man presented for routine surveillance following chemoradiation for laryngeal cancer completed in 2005. He was asymptomatic on initial evaluation in clinic. Physical examination revealed postradiation changes of the larynx including scarring and swelling of the supraglottic larynx, particularly the epiglottis, and an area of leukoplakia on the posterior aspect of the left supraglottic larynx. The patient had normal vocal fold function and no exophytic masses. This patient was deemed a good candidate for robot-assisted surgery using the MOR system. Informed consent was obtained for examination of the larynx and removal of the two leukoplakic lesions of the left aryepiglottic fold, including the necessity to convert to a traditional direct microlaryngoscopy and biopsy of the lesion. He also consented for use of the MOR system under an IRB-approved protocol. Procedure Direct laryngoscopy was performed under general anesthesia. An endotracheal tube was secured to the right retromolar trigone with 2-0 silk suture. A subcentimeter area of leukoplakia was identified on the left aryepiglottic fold. The MOR retractor was placed in the oral cavity using an appropriate curved blade, and the device was suspended using the MOR suspension block. The robot was docked using a 30-degree endoscope, with Bovie on the right and Maryland forceps on the left. The retractor allowed the larynx and the surrounding area to be viewed without use of a retraction tongue suture. The lesion was accessed and excised. There was no bleeding or other operative complications. The oropharynx was irrigated and the patient was turned over to anesthesia. Pathology of the biopsy showed benign squamous mucosa and submucosal tissue with chronic inflammation, fibrosis, and stromal atypia consistent with his history of radiation therapy. The MOR system again demonstrated that access to the glottis area was possible with the robot even though this was not required in this case. Instrumentation for glottis surgery from Intuitive Surgical is nonexistent. Follow-up The patient had no recurrence at 15-month follow-up.
FIGURE 5. Demonstrative intraoperative access of the epiglottis (A), supraglottic lesion (B), and pyriform sinus (C).
Case report #3 A 78-year-old woman presented with a right supraglottic cystic mass that recurred with associated inspiratory stridor. She was asymptomatic on evaluation in clinic. Biopsy of the mass was positive for benign oncocytoma. Physical examination revealed a right supraglottic lesion based within the medial aryepiglottic fold extending to the false vocal fold, which had
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Yes
Yes
No
Yes Yes Yes Closed: Curved Rectangle
Yes Yes
Yes
Articulates relative to handle Articulates relative to handle Articulates relative to handle Yes Yes
No
Yes Fixed Yes Yes
Closed: Curved Rectangle Closed: Curved Rectangle Open: Oval
Yes
Fixed Fixed Fixed Fixed No Yes Yes Yes No No Yes Yes No No No No
Face Frame Retractor
Closed: Rectangle Open: Oval Closed: Square Closed: Rectangle
Blade Rotation Around Central Axis Blade AnteriorPosterior Advancement Narrow Laryngeal Blade
DISCUSSION Previous studies of retractors for robotic laryngeal work show insufficient visualization of the glottis (Table 1). Two studies used the Dingman mouthgag and a 30° scope to attain a working view of the larynx in a mannequin and a cadaver, respectively.3,4 Lalich et al invented a retractor and conducted a study in cadavers with adequate access reported, but the retractor has not been trialed in an in vivo human model to date.5 One study required the use of anterior tongue retraction with a 2.0 silk suture, malleable blade to retract the tongue base, and a Lindholm scope to retract the epiglottis. The robotic arms were inserted on either side of the Lindholm scope.6 Since that time, Hasskamp et al have also designed a robotic system including a retractor to provide adequate glottic exposure and access during transoral robotic surgery. In vivo studies of this new retractor also report continued difficulty exposing the false cords and the glottic larynx. They do not report resection of glottic lesions and showed difficulty with resection of supraglottic lesions, likely related to increasing difficulty of exposure with increasing depth of the lesion in the upper airway.10–12 An advantage of our retractor over the system proposed by Hasskamp et al is that our retractor enables the da Vinci system feasible to use for other head and neck procedures as opposed to acquiring an entirely new robotic retraction system. Resection of T1 glottic cancers has been successful in a small number of studies, but inadequate exposure was a recurrent theme.7–9,13 A Feyh-Kastenbauer retractor was used in two studies, but the cumbersome nature of the retractor resulted in colli-
TABLE 1. Characteristics of Currently Available Retractors for Robotic Microlaryngeal Surgery
Follow-up The patient has had no recurrence, no dysphagia, or other complications at 15-month follow-up.
Frame Articulation
Procedure After general anesthesia induction and a direct laryngoscopy were performed, a shoulder roll was inserted. The MOR was inserted into the oral cavity using an appropriate curved blade and was suspended using the MOR suspension block. The improved exposure eliminated the need for a retraction tongue suture. The robot was set up using Marilyn forceps on the left and the OmniGuide laser controlled with needle drivers on the right. The lesion was able to be visualized using the MOR retractor, which allowed excision of the lesion including the medial aryepiglottic fold and supraglottic fold extending down into the lateral musculature of the supralarynx and involving most of the false cord. Before the removal of the mass, the right true vocal cord was unable to be visualized, but it was easily visualized on removal of the mass and, more importantly, was able to be easily accessed by the robot’s instruments. Afrin-soaked pledgets were used to achieve hemostasis. The operation was finished with no complications and negligible blood loss.
Dingman Crowe-Davis Feyh-Kastenbauer (FK) Feyh-Kastenbauer WeisteinO’Malley (FK-WO) Laryngeal Advanced Retractor System (LARS) Lalich Microlaryngeal Robotic Retractor Modular Oral Retractor (MOR) System Flex Retractor
Used in Live Humans
the potential to compromise the patient’s airway. She was deemed a candidate for laryngeal robot-assisted partial laryngectomy using the MOR system. Informed consent was obtained for examination of the larynx and excision of the tumor. She also consented for use of the MOR system under an IRB-approved protocol.
Yes Yes Yes Yes
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FIGURE 6. The MOR system allows the frame to be rotated relative to the handle and for blade rotation around the central access. It is shown here without a tongue blade. sion with the robotic arms and limited access to the anterior commissure in both studies.1,6 Our method showed successful robotic-assisted resection of supraglottic lesions using the MOR system and, importantly, excellent exposure to the glottis in all cases using the da Vinci system. The MOR system’s open face frame allowed more space for the robotic arms to move during a procedure and eliminated the need for a rigid scope and a stay suture to retract the tongue. The MOR system’s 15 blades are customized to overcome commonly encountered anatomical challenges including a large tongue, large base of tongue, or an epiglottis that obscures view of the anterior glottis. The 360° axis of rotation at the juncture of the base of the blade and the inferior portion of the mouth retractor allowed complete exposure of the entire glottis, which will likely eliminate the need for a tongue suture in most patients as it did for the patients included in this study. This axis of rotation is not available on the Dingman mouthgag or the Lalich retractor. The curvature of some of the available MOR blades also serves to push the base of the tongue anteriorly and allows adequate visualization of the glottis. The maxillary brace has a 360° axis of rotation that further augments the ability of the retractor to push the tongue and epiglottis forward, allowing visualization of the glottis (Figure 6) as well as giving the retractor a more stable purchase on the maxilla. The ability to rotate multiple parts of the retractor around an axis to maximize exposure is not possible with other retractors that have been proposed for use in robotic surgery. The maxillary brace is very similar to a Crowe-Davis retractor, but the maxillary brace of the MOR retractor is safer than the Dingman mouthgag because it diffuses dental pressure from canine to canine across the superior alveolus, whereas the Dingman has two dental braces that anchor on one tooth on each side of the superior alveolus. However, no objective data exist to support this observation. Other retractors may have some advantageous aspects to allow for adequate exposure, but the MOR system has the most comprehensive profile to facilitate feasible RMLS. The excellent exposure provided by the MOR retractor allowed for easy use of the robot in the three cases presented in this series. The
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robot had 360° access to the lesions, and the resections were completed without difficulty. The inherent deficiency in any small case series is patient selection. The patients included in this series may have been more anatomically favorable for laryngeal robotic surgery than others. It has been shown that those who are obese tend to carry more tissue in the base of their tongue, which adds volume in that area.14 Thus, a patient who is obese with a large tongue will likely be a poorer candidate for possible RMLS despite the type of retractor that is used. However, the versatility of our retractor may allow some obese patients to become candidates for robotic surgery, whereas their anatomy may preclude their candidacy using other retractors. An anteriorly located larynx would also be a cause for difficult exposure with any retractor including the MOR system. However, the photographic documentation clearly demonstrates that glottic exposure is excellent and that it could allow for glottic procedures. Unfortunately, the main limitation with the da Vinci system is inadequate surgical instrumentation to perform microlaryngeal surgery. The instruments are too large and the forceps and scissors, for example, are too coarse and bulky for any meaningful microlaryngeal surgery to be performed. These instruments were primarily designed for abdominal surgery, and as far as we know, Intuitive Surgical has no plans to create laryngeal-specific instrumentation. Disadvantages of RMLS therefore include poor robotic instrumentation with the da Vinci system, limited tactile feedback requiring the surgeon to rely on visual cues, and limited robotic training programs. Long-term results need to be compared with traditional surgery to determine outcomes using this method.13 The blade on the retractor can retract the epiglottis, which is sometimes necessary for exposure depending on the patient’s anatomy as opposed to inserting the blade tip into the vallecula.
CONCLUSION The potential for RMLS using the MOR system was demonstrated in our case series. We propose that by using this retractor, RMLS may improve on traditional techniques by reducing the need for a retraction tongue suture, providing adequate anterior commissure exposure, allowing 360° access to the lesion, and eliminating the narrowed view of a traditional laryngoscope. Technological advancements such as the new da Vinci Xi robotic system may allow the MOR system to make RMLS more feasible especially if robotic microlaryngeal instruments are created by Intuitive Surgical. In this regard, the Medrobotics Flex system (Raynham, MA) has an advantage over the Intuitive Surgical system in that instruments have been specifically designed for microlaryngeal surgery. Preliminary work has shown that the MOR system provides excellent exposure to the larynx including the glottis. Intuitive Surgical Inc. does not currently produce microlaryngeal instrumentation to take advantage of the glottic exposure provided by the MOR system. Unlike the Intuitive Surgical system, Medrobotics has created fine microlaryngeal instruments that allow delicate procedures to be performed on the vocal cords. Prospective research comparing RMLS and traditional microlaryngeal surgery is needed to determine the comparative outcomes of each method.
ARTICLE IN PRESS 6 COMPLIANCE WITH ETHICAL STANDARDS This case report did not require financial support. The authors received a clinical research grant from Intuitive Surgical, Inc. to continue to perform and present research using the MOR system. The grant did not and was not intended to fund any aspect of the retractor’s design, manufacturing, marketing, or use. The MOR system was created several years before obtaining this grant. All development of the MOR system has been under the supervision of the University of Oklahoma Board of Regents. Acknowledgments Marina Medical Inc. (Sunrise, FL) provided assistance in engineering and production of the MOR system. Intuitive Surgical has awarded $5000 for travel purposes for all authors to present research related to the MOR retractor. Intuitive Surgical Inc. did not have a role in the design, collection, analysis, or interpretation of data. Intuitive Surgical Inc. had no role in development or use of the MOR system. REFERENCES 1. Dogan S, Aybek T, Westphal K, et al. Computer-enhanced totally endoscopic sequential coronary artery bypass. Ann Thorac Surg. 2001;72: 610–611. 2. Menon M, Shrivasta A, Sarle R, et al. Vattikuti Institute Prostatectomy: a single-team experience of 100 cases. J Endourol. 2003;17:785– 790.
Journal of Voice, Vol. ■■, No. ■■, 2017 3. Hockstein NG, Nolan JP, O’Malley BW Jr, et al. Robot-assisted pharyngeal and laryngeal microsurgery: results of robotic cadaver dissections. Laryngoscope. 2005a;115:1003–1008. 4. Hockstein NG, Nolan JP, O’Malley BW Jr, et al. Robotic microlaryngeal surgery: a technical feasibility study using the da Vinci surgical robot and an airway mannequin. Laryngoscope. 2005b;115:780–785. 5. Lalich IJ, Olsen SM, Ekbom DC. Robotic microlaryngeal surgery: feasibility using a newly designed retractor and instrumentation. Laryngoscope. 2014;124:1624–1630. 6. Blanco RG, Ha PK, Califano JA, et al. Transoral robotic surgery of the vocal cord. J Laparoendosc Adv Surg Techn A. 2011;21:157–159. 7. Park YM, Lee WJ, Lee JG, et al. Transoral robotic surgery (TORS) in laryngeal and hypopharyngeal cancer. J Laparoendosc Adv Surg Techn A. 2009;19:361–368. 8. Kayhan FT, Kaya KH, Sayin I. Transoral robotic cordectomy for early glottic carcinoma. Ann Otol Rhinol Laryngol. 2012;121:497–502. 9. Lallemant B, Chambon G, Garrel R, et al. Transoral robotic surgery for the treatment of T1-T2 carcinoma of the larynx: preliminary study. Laryngoscope. 2013;123:2485–2490. 10. Hasskamp P, Lang S, Holtmann L, et al. First use of a new retractor in transoral robotic surgery (TORS). Eur Arch Otorhinolaryngol. 2016;273:1913–1917. 11. Mattheis S, Hasskamp P, Holtmann L, et al. Flex Robotic System in transoral robotic surgery: The first 40 patients. Head Neck. 2016;doi:10.1002/ hed.24611. Epub ahead of print. 12. Lang S, Mattheis S, Hasskamp P, et al. A European multicenter study evaluating the flex robotic system in transoral robotic surgery. Laryngoscope. 2016;127:391–395. 13. Byrd JK, Duvvari U. Current trends in robotic surgery for otolaryngology. Curr Otorhinolaryngol Rep. 2013;1:153–157. 14. Kim AM, Keenan BT, Jackson N, et al. Tongue fat and its relationship to obstructive sleep apnea. Sleep. 2014;37:1639–1648.
different methods of exposure. A recurring theme during these investigations is that multiple instruments have to be used to obtain access to the glottis, and space for the robotic instruments is limited.3–5 Traditional microlaryngeal surgery is limited to direct laryngoscopes, which do not allow 360° access to glottic lesions. Twenty-five-centimeter-long instruments are introduced through the laryngoscope to reach the vocal folds, magnifying the surgeon’s tremor. The procedure is analogous to an attempt to write fine cursive by holding on to the distal end of a 25-cm-long pen. Visualization is limited to the small view provided through the laryngoscope using a microscope. Several retractors have been used in RMLS including the FeyhKastenbauer, Laryngeal Advanced Retractor System, and Dingman retractors. A common theme in the literature is the armamentarium of robotic retractors often provides inadequate access to the glottis, especially in the area of the anterior commissure because of poor tongue retraction. Oral commissure retraction has also been reported to be insufficient.3–10 We had previously proposed a device called the Modular Oral Retractor (MOR) system that is able to easily obtain a view of the glottis with the robot and maximize space in the glottic region to allow the robotic arms to function (see Figure 1). The device potentially enables RMLS to be performed. It provides improved oral commissure and tongue base retraction, allowing room for the robotic arms to work and excellent anterior commissure exposure. The face frame is open to allow more space for the robotic arms to move during a procedure. The MOR system eliminates the need for a rigid laryngoscope, which narrows the visual field, increases the distance of the working view to the surgical site, and serves as an obstacle around which robotic arms have to work. The 360° axis of rotation at the juncture of the base of the blade and the inferior portion of the mouth retractor allows superb exposure of the entire glottis, which may eliminate the need for a tongue suture, potentially decreasing incidence of tongue edema, airway complications, and postoperative patient discomfort. The axis of rotation at the base of the blade optimizes elevation of the tongue and allows for retraction of the tongue down to the vallecula, an option not available
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Case #1 A 56-year-old man with a long history of smoking initially presented with progressive hoarseness and dysphagia for 8 months and underwent direct laryngoscopy and biopsy at an outside facility, which showed squamous hyperplasia of the bilateral true vocal folds and diffuse, severe supraglottic hypertrophy. Nasopharyngoscopy performed in our clinic revealed redundant supraglottic mucosa that prolapsed into the glottic airway with associated plicae ventricularis, retroflexed epiglottis, and prolapsed aryepiglottic folds. It was not possible to view the glottis because of the redundant mucosa. The remainder of the head and neck examination was unremarkable. The patient was deemed a good candidate for robotic-assisted surgery using the MOR system. Informed consent was obtained for examination of the larynx and removal of the obstructing mucosa with a CO2 laser. He consented for use of the MOR system under an institutional review board (IRB)-approved protocol.
FIGURE 1. The Modular Oral Retractor (MOR) system with a removable tongue blade that allows for anterior and posterior advancement. with other retractors. The maxillary brace also has a 360° axis of rotation that further augments the ability of the retractor to push the tongue and the epiglottis forward, allowing visualization of the glottis. The MOR system includes 15 different blades that are interchangeable based on each patient’s unique anatomy to provide an optimal view of the glottis (Figure 2). We present a case series of three patients, which further demonstrates the ease with which the MOR retractor can facilitate visualization and access to the glottic area.
FIGURE 2. The different blades available to use with the MOR system.
Procedure After general anesthesia was induced and a shoulder roll was inserted, the MOR was inserted into the oral cavity using an appropriate curved blade and was suspended using the MOR suspension block. The retractor gave excellent access to the larynx (see Figure 3). The tongue blade used was a curved type that was inserted into the vallecular space. There are multiple blade types available with the MOR system that takes into account the differences in anatomy between patients. When initially inserting the retractor using a headlight, the curve of the tongue blade provided elevation of the epiglottis, which exposed the arytenoid mucosa. In some patients, more of the glottic larynx may be seen and these patients are easier candidates for robotic surgery. Following docking of the robot, the entire glottis including the anterior vocal folds could be visualized with the 30° upward directed scope, but more importantly, accessed by the robotic arms (see Figure 4). Ultrafine microlaryngeal procedures cannot be
FIGURE 3. The MOR system in place demonstrating the access available to the supraglottic and glottic regions of the throat for surgery.
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of supraglottic tissue, including using a laryngoscope with dysplastic biopsies negative for malignancy. Follow-up Six months postoperatively, the patient was diagnosed with laryngeal squamous cell carcinoma and underwent total laryngectomy. He had no recurrence of malignancy at 18month follow-up status post laryngectomy.
FIGURE 4. The MOR system with robotic arms in place for surgery. satisfactorily performed with Intuitive Surgical instrumentation as these instruments were primarily designed for the abdomen. The improved exposure eliminated the need for a retraction tongue suture. The robot is docked with a Maryland dissector to the left and a needle driver on the right that allows mobilization and use of the OmniGuide CO2 laser (Lexington, MA). Setup using the retractor was relatively simple. The redundant mucosa on the superior aspect of the arytenoid cartilage on the left was excised completely using the laser at 15 watts. Unlike access obtained during microlaryngoscopy with a superiorto-inferior orientation within a narrow scope, tissue could be excised using the laser in a side-to-side manner, which is impossible with microlaryngoscopy. The MOR system therefore allows multiple surgical orientation options at the target tissue level. Hemostasis was achieved with the laser and suction cautery. A similar procedure was performed on the left side. The interarytenoid area was not treated to avoid contracture. The redundant mucosa was easily mobilized with the Maryland forceps (see Figure 5). Because the patient had generalized edema, we elected to ablate the false cord on the left side, which was prominent. There were no complications during the procedure. The patient was monitored closely and had undergone multiple debridements
Case #2 A 79-year-old man presented for routine surveillance following chemoradiation for laryngeal cancer completed in 2005. He was asymptomatic on initial evaluation in clinic. Physical examination revealed postradiation changes of the larynx including scarring and swelling of the supraglottic larynx, particularly the epiglottis, and an area of leukoplakia on the posterior aspect of the left supraglottic larynx. The patient had normal vocal fold function and no exophytic masses. This patient was deemed a good candidate for robot-assisted surgery using the MOR system. Informed consent was obtained for examination of the larynx and removal of the two leukoplakic lesions of the left aryepiglottic fold, including the necessity to convert to a traditional direct microlaryngoscopy and biopsy of the lesion. He also consented for use of the MOR system under an IRB-approved protocol. Procedure Direct laryngoscopy was performed under general anesthesia. An endotracheal tube was secured to the right retromolar trigone with 2-0 silk suture. A subcentimeter area of leukoplakia was identified on the left aryepiglottic fold. The MOR retractor was placed in the oral cavity using an appropriate curved blade, and the device was suspended using the MOR suspension block. The robot was docked using a 30-degree endoscope, with Bovie on the right and Maryland forceps on the left. The retractor allowed the larynx and the surrounding area to be viewed without use of a retraction tongue suture. The lesion was accessed and excised. There was no bleeding or other operative complications. The oropharynx was irrigated and the patient was turned over to anesthesia. Pathology of the biopsy showed benign squamous mucosa and submucosal tissue with chronic inflammation, fibrosis, and stromal atypia consistent with his history of radiation therapy. The MOR system again demonstrated that access to the glottis area was possible with the robot even though this was not required in this case. Instrumentation for glottis surgery from Intuitive Surgical is nonexistent. Follow-up The patient had no recurrence at 15-month follow-up.
FIGURE 5. Demonstrative intraoperative access of the epiglottis (A), supraglottic lesion (B), and pyriform sinus (C).
Case report #3 A 78-year-old woman presented with a right supraglottic cystic mass that recurred with associated inspiratory stridor. She was asymptomatic on evaluation in clinic. Biopsy of the mass was positive for benign oncocytoma. Physical examination revealed a right supraglottic lesion based within the medial aryepiglottic fold extending to the false vocal fold, which had
ARTICLE IN PRESS 4
Yes
Yes
No
Yes Yes Yes Closed: Curved Rectangle
Yes Yes
Yes
Articulates relative to handle Articulates relative to handle Articulates relative to handle Yes Yes
No
Yes Fixed Yes Yes
Closed: Curved Rectangle Closed: Curved Rectangle Open: Oval
Yes
Fixed Fixed Fixed Fixed No Yes Yes Yes No No Yes Yes No No No No
Face Frame Retractor
Closed: Rectangle Open: Oval Closed: Square Closed: Rectangle
Blade Rotation Around Central Axis Blade AnteriorPosterior Advancement Narrow Laryngeal Blade
DISCUSSION Previous studies of retractors for robotic laryngeal work show insufficient visualization of the glottis (Table 1). Two studies used the Dingman mouthgag and a 30° scope to attain a working view of the larynx in a mannequin and a cadaver, respectively.3,4 Lalich et al invented a retractor and conducted a study in cadavers with adequate access reported, but the retractor has not been trialed in an in vivo human model to date.5 One study required the use of anterior tongue retraction with a 2.0 silk suture, malleable blade to retract the tongue base, and a Lindholm scope to retract the epiglottis. The robotic arms were inserted on either side of the Lindholm scope.6 Since that time, Hasskamp et al have also designed a robotic system including a retractor to provide adequate glottic exposure and access during transoral robotic surgery. In vivo studies of this new retractor also report continued difficulty exposing the false cords and the glottic larynx. They do not report resection of glottic lesions and showed difficulty with resection of supraglottic lesions, likely related to increasing difficulty of exposure with increasing depth of the lesion in the upper airway.10–12 An advantage of our retractor over the system proposed by Hasskamp et al is that our retractor enables the da Vinci system feasible to use for other head and neck procedures as opposed to acquiring an entirely new robotic retraction system. Resection of T1 glottic cancers has been successful in a small number of studies, but inadequate exposure was a recurrent theme.7–9,13 A Feyh-Kastenbauer retractor was used in two studies, but the cumbersome nature of the retractor resulted in colli-
TABLE 1. Characteristics of Currently Available Retractors for Robotic Microlaryngeal Surgery
Follow-up The patient has had no recurrence, no dysphagia, or other complications at 15-month follow-up.
Frame Articulation
Procedure After general anesthesia induction and a direct laryngoscopy were performed, a shoulder roll was inserted. The MOR was inserted into the oral cavity using an appropriate curved blade and was suspended using the MOR suspension block. The improved exposure eliminated the need for a retraction tongue suture. The robot was set up using Marilyn forceps on the left and the OmniGuide laser controlled with needle drivers on the right. The lesion was able to be visualized using the MOR retractor, which allowed excision of the lesion including the medial aryepiglottic fold and supraglottic fold extending down into the lateral musculature of the supralarynx and involving most of the false cord. Before the removal of the mass, the right true vocal cord was unable to be visualized, but it was easily visualized on removal of the mass and, more importantly, was able to be easily accessed by the robot’s instruments. Afrin-soaked pledgets were used to achieve hemostasis. The operation was finished with no complications and negligible blood loss.
Dingman Crowe-Davis Feyh-Kastenbauer (FK) Feyh-Kastenbauer WeisteinO’Malley (FK-WO) Laryngeal Advanced Retractor System (LARS) Lalich Microlaryngeal Robotic Retractor Modular Oral Retractor (MOR) System Flex Retractor
Used in Live Humans
the potential to compromise the patient’s airway. She was deemed a candidate for laryngeal robot-assisted partial laryngectomy using the MOR system. Informed consent was obtained for examination of the larynx and excision of the tumor. She also consented for use of the MOR system under an IRB-approved protocol.
Yes Yes Yes Yes
Journal of Voice, Vol. ■■, No. ■■, 2017
ARTICLE IN PRESS Dehra A McGuire, et al
Robotic Retractor for Glottic Exposure
FIGURE 6. The MOR system allows the frame to be rotated relative to the handle and for blade rotation around the central access. It is shown here without a tongue blade. sion with the robotic arms and limited access to the anterior commissure in both studies.1,6 Our method showed successful robotic-assisted resection of supraglottic lesions using the MOR system and, importantly, excellent exposure to the glottis in all cases using the da Vinci system. The MOR system’s open face frame allowed more space for the robotic arms to move during a procedure and eliminated the need for a rigid scope and a stay suture to retract the tongue. The MOR system’s 15 blades are customized to overcome commonly encountered anatomical challenges including a large tongue, large base of tongue, or an epiglottis that obscures view of the anterior glottis. The 360° axis of rotation at the juncture of the base of the blade and the inferior portion of the mouth retractor allowed complete exposure of the entire glottis, which will likely eliminate the need for a tongue suture in most patients as it did for the patients included in this study. This axis of rotation is not available on the Dingman mouthgag or the Lalich retractor. The curvature of some of the available MOR blades also serves to push the base of the tongue anteriorly and allows adequate visualization of the glottis. The maxillary brace has a 360° axis of rotation that further augments the ability of the retractor to push the tongue and epiglottis forward, allowing visualization of the glottis (Figure 6) as well as giving the retractor a more stable purchase on the maxilla. The ability to rotate multiple parts of the retractor around an axis to maximize exposure is not possible with other retractors that have been proposed for use in robotic surgery. The maxillary brace is very similar to a Crowe-Davis retractor, but the maxillary brace of the MOR retractor is safer than the Dingman mouthgag because it diffuses dental pressure from canine to canine across the superior alveolus, whereas the Dingman has two dental braces that anchor on one tooth on each side of the superior alveolus. However, no objective data exist to support this observation. Other retractors may have some advantageous aspects to allow for adequate exposure, but the MOR system has the most comprehensive profile to facilitate feasible RMLS. The excellent exposure provided by the MOR retractor allowed for easy use of the robot in the three cases presented in this series. The
5
robot had 360° access to the lesions, and the resections were completed without difficulty. The inherent deficiency in any small case series is patient selection. The patients included in this series may have been more anatomically favorable for laryngeal robotic surgery than others. It has been shown that those who are obese tend to carry more tissue in the base of their tongue, which adds volume in that area.14 Thus, a patient who is obese with a large tongue will likely be a poorer candidate for possible RMLS despite the type of retractor that is used. However, the versatility of our retractor may allow some obese patients to become candidates for robotic surgery, whereas their anatomy may preclude their candidacy using other retractors. An anteriorly located larynx would also be a cause for difficult exposure with any retractor including the MOR system. However, the photographic documentation clearly demonstrates that glottic exposure is excellent and that it could allow for glottic procedures. Unfortunately, the main limitation with the da Vinci system is inadequate surgical instrumentation to perform microlaryngeal surgery. The instruments are too large and the forceps and scissors, for example, are too coarse and bulky for any meaningful microlaryngeal surgery to be performed. These instruments were primarily designed for abdominal surgery, and as far as we know, Intuitive Surgical has no plans to create laryngeal-specific instrumentation. Disadvantages of RMLS therefore include poor robotic instrumentation with the da Vinci system, limited tactile feedback requiring the surgeon to rely on visual cues, and limited robotic training programs. Long-term results need to be compared with traditional surgery to determine outcomes using this method.13 The blade on the retractor can retract the epiglottis, which is sometimes necessary for exposure depending on the patient’s anatomy as opposed to inserting the blade tip into the vallecula.
CONCLUSION The potential for RMLS using the MOR system was demonstrated in our case series. We propose that by using this retractor, RMLS may improve on traditional techniques by reducing the need for a retraction tongue suture, providing adequate anterior commissure exposure, allowing 360° access to the lesion, and eliminating the narrowed view of a traditional laryngoscope. Technological advancements such as the new da Vinci Xi robotic system may allow the MOR system to make RMLS more feasible especially if robotic microlaryngeal instruments are created by Intuitive Surgical. In this regard, the Medrobotics Flex system (Raynham, MA) has an advantage over the Intuitive Surgical system in that instruments have been specifically designed for microlaryngeal surgery. Preliminary work has shown that the MOR system provides excellent exposure to the larynx including the glottis. Intuitive Surgical Inc. does not currently produce microlaryngeal instrumentation to take advantage of the glottic exposure provided by the MOR system. Unlike the Intuitive Surgical system, Medrobotics has created fine microlaryngeal instruments that allow delicate procedures to be performed on the vocal cords. Prospective research comparing RMLS and traditional microlaryngeal surgery is needed to determine the comparative outcomes of each method.
ARTICLE IN PRESS 6 COMPLIANCE WITH ETHICAL STANDARDS This case report did not require financial support. The authors received a clinical research grant from Intuitive Surgical, Inc. to continue to perform and present research using the MOR system. The grant did not and was not intended to fund any aspect of the retractor’s design, manufacturing, marketing, or use. The MOR system was created several years before obtaining this grant. All development of the MOR system has been under the supervision of the University of Oklahoma Board of Regents. Acknowledgments Marina Medical Inc. (Sunrise, FL) provided assistance in engineering and production of the MOR system. Intuitive Surgical has awarded $5000 for travel purposes for all authors to present research related to the MOR retractor. Intuitive Surgical Inc. did not have a role in the design, collection, analysis, or interpretation of data. Intuitive Surgical Inc. had no role in development or use of the MOR system. REFERENCES 1. Dogan S, Aybek T, Westphal K, et al. Computer-enhanced totally endoscopic sequential coronary artery bypass. Ann Thorac Surg. 2001;72: 610–611. 2. Menon M, Shrivasta A, Sarle R, et al. Vattikuti Institute Prostatectomy: a single-team experience of 100 cases. J Endourol. 2003;17:785– 790.
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