Robotic Facelift Thyroidectomy: I. Preclinical Simulation and Morphometric Assessment

Transcription

1 The Laryngoscope VC 2011 The American Laryngological, Rhinological and Otological Society, Inc. Robotic Facelift Thyroidectomy: I. Preclinical Simulation and Morphometric Assessment Michael C. Singer, MD; Melanie W. Seybt, MD; David J. Terris, MD Objectives: Robotic thyroidectomy was introduced in the United States despite scant preclinical data. We pursued a systematic preclinical investigation of a new remote access, robotic thyroidectomy technique via a facelift incision, and sought to define differences in extent of dissection associated with this approach and a second, popular robotic thyroidectomy technique. Design: Surgical simulation and morphometric analysis in fresh human cadavers. Methods: Eleven specimens were obtained to complete four experiments designed to address two specific aims: to develop a reproducible surgical protocol for robotic removal of the thyroid through a facelift incision, and to quantify the extent of dissection required with two robotic thyroidectomy techniques. Results: The feasibility of the facelift approach was determined using an endoscopic technique, and two lobectomies were accomplished. Inanimate study of the optimal robotic positioning to facilitate resection was then completed. Three additional cadavers were used to develop a reproducible surgical protocol and define a stepwise algorithm of dissection. Seven specimens were used to simulate 28 robotic thyroidectomy dissection pockets. The mean area of dissection required for robotic facelift thyroidectomy was cm 2 compared with cm 2 for robotic axillary thyroidectomy, representing a difference of 38.3% (P <.0001). Conclusions: We have described and refined a reproducible surgical protocol for accomplishing a new robotic facelift thyroidectomy, and then quantified the reduced dissection required when comparing it with a transaxillary technique. Cautious clinical implementation to explore safety and feasibility appears to be justified. Key Words: Robotic, endoscopic, facelift, cosmetic, thyroidectomy, remote access. Level of Evidence: N/A. Laryngoscope, 121: , 2011 INTRODUCTION The contributions made by Theodore Kocher to the practice of thyroid surgery have stood the test of time for over a century. 1 Impeccable dissection and absolute hemostasis remain fundamental principles of all thyroidectomy techniques. However, in the past 10 years a transformation has taken place in surgical approaches to the thyroid compartment. 2 The development of minimally invasive techniques has matured into the videoassisted cervical approach described and popularized by Paolo Miccoli. 3 Simultaneously, remote access techniques have evolved (particularly in Asia) in an effort to completely eliminate a visible neck scar. 4 6 In the past 2 years, the da Vinci robot has been exploited as a technology to facilitate the performance of several of these techniques. A bilateral axillary breast approach is per- From the Department of Otolaryngology Head and Neck Surgery, Georgia Health Sciences University, Augusta, Georgia, U.S.A. Editor s Note: This Manuscript was accepted for publication March 22, The authors have no financial disclosures for this article. No monetary support was received for this study. Some of the cadavers and the use of a training robot were provided by Intuitive Surgical, Inc. Dr. Terris has directed a series of thyroid courses sponsored by J&J. Send correspondence to Dr. David J. Terris, Surgical Director, GeorgiaHealth Thyroid Center, Department of Otolaryngology, Georgia Health Sciences University, 1120 Fifteenth Street, BP-4109, Augusta, GA dterris@georgiahealth.edu DOI: /lary formed with some degree of regularity, 7 but the gasless robotic axillary thyroidectomy (RAT) as proposed by Chung has emerged as the predominant method. 8 Despite a single surgeon experience of more than 1,500 RAT s in the past 3 years, there have been early challenges associated with its application in the United States. Perhaps reflective of larger patients with bigger necks and larger volume disease compared with the Korean population, a number of serious complications have been described. Many of these relate to the challenge posed by crossing the clavicle. In order to reduce the obstruction posed by this structure, specific positioning is required, which puts the brachial plexus at risk of stretch injury. 9 Furthermore, the technique requires an unfamiliar and uncommon approach that splits the sternal and clavicular heads of the sternocleidomastoid muscle, and an angle that places the esophagus at higher risk for injury compared with a transcervical thyroidectomy. A more natural remote access robotic approach was therefore sought. The foundations for a facelift-based option originated in a combination of concepts represented by a facelift parotidectomy, 10 retroauricular access to the thyroid compartment, 11 the gasless technique popularized by Miccoli, 2 and the fixed retractor system introduced by Chung. 12 Prior investigations in our laboratory suggested a superior to inferior approach to the thyroid compartment is the easiest and fastest of several potential remote access options for thyroid surgery

2 We were motivated to systematically explore a novel facelift technique in a preclinical cadaver model (as has been done previously by our group for other endoscopic and robotic neck procedures). 14,15 These prior studies represented a framework that has proven to be a useful mechanism for establishing the feasibility, safety, and value of new robotic procedures. We therefore report our investigations of robotic facelift thyroidectomy (RFT), which provided the justification for proceeding to gradual clinical implementation. 16 METHODS AND MATERIALS A series of experiments was undertaken in a stepwise fashion in order to explore two specific aims. Specific Aim 1: To develop a reproducible surgical protocol for the endoscopic and robotic removal of the thyroid gland through a facelift incision. Specific Aim 2: To objectively quantify the extent of dissection required with two different robotic thyroidectomy techniques. Fresh, unembalmed cadavers were obtained. The absence of prior neck surgery was confirmed by the lack of a neck scar. Experiments were carried out in a state-of-the-art anatomy dissection laboratory (Georgia Health Sciences University, Augusta, GA) and in a robotic training facility (Intuitive Surgical Inc, Sunnyvale, CA) to address the specific aims that had been identified. Experiments 1 to 3 were conceived to achieve aim 1 and Experiment 4 was designed to achieve aim 2. Experiment 1 The first cadaver was used to explore the feasibility of a superior to inferior approach to the thyroid compartment that has as its access point the retroauricular and hairline region (similar to a facelift approach). In the first experiment, a cadaver was used to accomplish two thyroid lobectomy simulations with a combination of open and endoscopic techniques in order to define the surgical approach and anatomic relationships. The planes of dissection were explored and the feasibility of this approach was assessed. Experiment 2 A human mannequin was positioned on an operating table and the surgical robot was positioned in a variety of relationships to the neck and the operating table to identify the optimal robotic positioning required to access the neck through a facelift incision with the least amount of interference of the robotic arms. Experiment 3 In the third experiment, three cadavers were used to simulate five thyroid lobectomies via the facelift approach using a combination of open and robotic techniques. These dissections were accomplished principally to optimize the fixed retraction system, the positioning of the robotic arms and the instrumentation (including existing and novel instruments). The potential advantage conferred by the application of robotic technology was assessed qualitatively. The feasibility of simultaneous bilateral robotic thyroid surgery was investigated. Experiment 4 In the final experiment, a second set of seven fresh, unembalmed human cadavers was used to undertake a morphometric 1632 study of surface anatomy in order to compare the area of dissection required in robotic facelift thyroidectomy versus transaxillary thyroidectomy. Procedural Details The cadavers were positioned supine on the dissection table, with the head turned slightly away from the side of the surgery. The specific procedural steps are described in greater detail in a separate publication 16 but the essential elements include an incision that was designed to be nearly identical to that previously described by our group for a modified facelift parotidectomy, 10 with the exception that no preauricular limb was included. A stepwise identification of landmarks was undertaken in open fashion (with loupe magnification), beginning with the sternocleidomastoid and followed by the greater auricular nerve and then the external jugular vein. The omohyoid muscle was isolated and retracted ventrally. The strap muscles were dissected and retracted anteriorly and medially, exposing the thyroid gland. A fixed retractor (Marina Medical, Orlando, FL) with a customized blade was used to maintain the operative pocket, and a Singer retractor (Augusta, GA) was used to retract the sternocleidomastoid muscle laterally and posteriorly. Endoscopic or robotic visualization was established in order to complete the thyroid lobectomy. For Experiment 1, a 5-mm, 30-degree laparoscope was angled downward to provide visualization, and the Harmonic ACE device (Ethicon Endosurgery, Cincinnati, OH) was used to dissect the thyroid gland and ligate the vasculature. The recurrent laryngeal nerves and the superior and inferior parathyroid glands were identified and preserved. In Experiment 3, the davinci robotic surgical system (Intuitive Surgical Inc.) was used to accomplish the thyroid resection. The camera arm was positioned first, and was placed parallel to the retractor. A Maryland grasper was placed in the nondominant arm, and the dominant arm controlled the Harmonic device. The operative times were recorded, and the wounds were opened after completion of robotic resection to confirm the thoroughness of tissue resection. Morphometric Anatomic Study In Experiment 4, a surface anatomical morphometric study was completed. Each cadaver was marked out bilaterally for a transaxillary thyroidectomy using well-defined landmarks, and with the appropriate positioning of the arm over the head. The same cadavers were then marked for a robotic facelift thyroidectomy. For each of these, the necessary area of dissection to accomplish the procedure was delineated using a marking pen. Standardized photographs were taken to allow comparison of these areas of dissection, which was accomplished using ImageJ software (National Institutes of Health). Statistical comparison of the areas of dissection was accomplished using a Student s t-test. RESULTS Experiment 1 Landmark Identification and Feasibility A facelift incision was used to gain access to the lateral neck in order to perform two cadaveric thyroid lobectomies (Fig. 1). A series of instruments and retractors were trialed to identify the optimal exposure necessary to reach the thyroid compartment. A customized Chung device (with modified blade; Marina Medical) provided adequate retraction when combined with a Singer retractor in order to accomplish an endoscopic thyroidectomy with a 5-mm laparoscope.

3 the thyroid gland and the integrity of the nerves and parathyroid glands. Fig. 1. A surgical pocket is created which is ventral to the greater auricular nerve and the external jugular vein (not shown), anterior to the sternocleidomastoid muscle (white arrowhead) and deep to the omohyoid muscle (black arrowhead). The superior pole of the thyroid gland (black arrow) is just visible at this stage of the dissection. Additional instrumentation included an electrocautery extender, Harmonic Ace 23-E (Ethicon Endosurgery Inc.) and Terris suction tips and elevators (Medtronic Inc, Jacksonville, Fl). Despite the learning curve associated with deliberate exploration of this novel approach, the time required to complete each of these lobectomies was under 1 hour, and critical structures including the recurrent laryngeal nerves and the parathyroid glands were identified. The neck was opened at the completion of the endoscopic procedures to confirm thorough removal of Experiment 2 Inanimate Study of Robotic Positioning After considerable trial and error it was determined that the robotic footprint should be adjacent to the pedestal of the operating table, and coming from the side contralateral to the thyroid lobe to be removed. To achieve consistent results, the precise location of these structures was marked with tape on the operating room floor (Fig. 2). Three arms were deemed to be sufficient to provide adequate visualization and maneuverability. Interference of the robotic elbows is common when a surgical pocket must be approached from a single vector, and strategies for reducing this interference were trialed and selected. A 30-degree down camera approaching the thyroid parallel to the fixed retractor blade resulted in the best operative view. Experiment 3 Preclinical Simulation Having thus developed the sequence of steps necessary to excise the thyroid utilizing a modified facelift incision, and with a logical approach to positioning of the robot identified, three additional fresh cadavers were obtained in order to evaluate the incremental value of the incorporation of the davinci surgical robot (Intuitive Surgical Inc.) to facilitate the procedure. Five consecutive robotic facelift thyroid lobectomies were accomplished using a three-robotic-arm technique, and without the need for a presternal or other portal (Fig. 3). The central arm was used to control the dual-lens scope (which provides three-dimensional visualization), one Fig. 2. Proper positioning of the three robotic arms within the anticipated surgical pocket was determined in a mannequin model (a), and the location of the patient-side robotic cart relative to the operating table was standardized and marked (b) in order to achieve consistency. 1633

4 Fig. 3. A right-sided robotic thyroidectomy is demonstrated in a cadaver model, with a fixed retractor system maintaining the operative pocket. arm was used for the Harmonic CS14C, and the final arm was used to control a Maryland grasping forceps. The technique was further refined over these five procedures and the specific steps of the procedure were standardized. The thyroid gland was easily and completely removed in each case, and no conversions to open were required. The recurrent laryngeal nerves were isolated and preserved, and the parathyroid glands were identified and kept intact. Finally, each thyroid bed was opened and explored after the resection was completed (as described above). The integrity of the recurrent laryngeal nerves and the parathyroid glands was confirmed. Experiment 4 Morphometric Analysis Measurements taken on both sides of the seven cadavers used in this experiment (Fig. 4) confirmed that the extent of dissection required to accomplish an axillary thyroidectomy was greater than that needed for an RFT in each case (Fig. 5), by an overall mean of 38.3%. The mean (6standard deviation) dissection field for RAT was cm 2 (range: cm 2 ), and for RFT it was cm 2 (range: cm 2 )(P <.0001). Fig. 5. The area of dissection required for a robotic axillary thyroidectomy was consistently greater than that needed for a robotic facelift thyroidectomy. The mean difference exceeded 38%, with a P value of < DISCUSSION Chung and his colleagues 12 in Korea have successfully applied robotic technology to the performance of thyroidectomy in order to facilitate remote access surgery. With their standardized protocol and high volumes, they have been able to achieve efficient surgical times and low complication rates. Despite these successes, challenges were quickly recognized when attempts were made to apply the transaxillary robotic thyroidectomy technique in North American patients by skilled and high-volume thyroid surgeons. 9,17 We therefore set out in search of an easier and safer technique. We incorporated a number of well-established principles and developed a hybrid technique based on the novel incremental advances established by a number of investigators. The evolution of the facelift approach borrowed key elements from the use of a modified facelift incision for parotidectomy previously described by Terris and colleagues, 10 the gasless endoscopic technique popularized by Miccoli and his team, 3 the concept of fixed external retraction introduced by Chung and his colleagues, 8 and the feasibility of a superior to inferior dissection of the thyroid. 11 Following a framework for Fig. 4. The area of dissection required for a robotic axillary thyroidectomy (a) and a robotic facelift thyroidectomy (b) were calculated using ImageJ software provided by the NIH. 1634

5 development of new robotic procedures that we established in 2000 and ,15 (which has been successfully followed by others), we have reported here initial preclinical findings from inanimate and cadaveric studies. Our results show that the robotic facelift thyroidectomy approach is feasible and can be performed in a consistent and reproducible manner in cadavers. With the use of widely available technology and instruments, augmented by select modified equipment, robotic facelift thyroidectomy is practical. Additional understanding was obtained from the surface anatomical study that compared the transaxillary technique to the robotic facelift technique. Specifically, the area of dissection that is required in order to accomplish a transaxillary thyroidectomy is fully 38% greater than that necessary for a robotic facelift approach. This has important implications regarding not only the time of surgery but more importantly the rate of recovery and pace of wound healing. We believe that a smaller area of dissection is an advantage as it may be presumed that a smaller area of dissection will take less time to accomplish, and will result in less tissue trauma. More rapid overall wound healing might therefore be expected. It should be acknowledged that this new approach might introduce novel potential complications. Most notable is the likelihood of temporary hypesthesia in the distribution of the greater auricular nerve, and the possibility of long-term anesthesia in this region. As with a facelift, there is a theoretical possibility of distal flap loss, especially in individuals who smoke. The feasibility and reproducibility of the robotic facelift technique was a crucial prerequisite that needed to be achieved in order to perform it in patients. A second requirement for introducing a new remote access technique into clinical practice was that it provided added value over traditional, minimally invasive and other remote access thyroidectomy techniques. Our results provide evidence that the robotic facelift approach satisfies both of these conditions and provide a basis for cautious clinical implementation in patients to explore safety and feasibility. CONCLUSIONS We have described and refined a reproducible surgical protocol for accomplishing a new robotic facelift thyroidectomy, and then quantified the reduced dissection required when comparing it with a transaxillary technique. Cautious clinical implementation to explore safety and feasibility appears to be justified. BIBLIOGRAPHY 1. Kocher. Ueber Kropfexstirpation und ihre Folgen. Archiv Klin Chir 1883; 29: Terris DJ, Stack BC. Current technology in thyroid surgery. ORL 2008;70: Miccoli P, Berti P, Materazzi G, Minuto M, Barellini L. Minimally invasive video-assisted thyroidectomy: five years of experience. J Am Coll Surg 2004;199: Cho YU, Park IJ, Choi KH, et al. Gasless endoscopic thyroidectomy via an anterior chest wall approach using a flap-lifting system. 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