TECHNICAL NOTE J Neurosurg 126:997–1002, 2017
Novel technique of a multifunctional electrosurgical system for minimally invasive surgery David Mittelstein, BS,1 Jiahan Deng, MS,2 Rachel Kohan, BS,2 Mojdeh Sadeghi, MS,2 Jean-Michel Maarek, PhD,2 and Gabriel Zada, MD, MS1 Department of Neurosurgery, Keck School of Medicine, and 2Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California
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Bipolar electrosurgery in the minimally invasive endoscopic surgery theater has been traditionally limited to the use of standard bipolar forceps, which are minimally versatile, have a limited range of motion, and are associated with visualization and handling constraints. The authors designed a novel surgical device system in which commonly used surgical instruments (suction, microscissors, micrograspers, and dissectors) co-function as individually insulated and modular electrodes for bipolar electrosurgery. In this feasibility study, the successful use of these prototypes in endonasal endoscopic transsphenoidal surgery was demonstrated on 2 human cadavers, and in an in vivo arterial coagulation model on 2 live rats. This prototype system provided improved bipolar instrument mobility, minimized the requirement to exchange surgical instruments when performing electrosurgery, and allowed for new maneuvers that optimized surgical workflow, such as the ability to suction blood and smoke while cauterizing. This multifunctional bipolar cautery system may improve surgical efficiency and workflow and facilitate surgical microdissection and electrocautery during minimally invasive, endoscopic, robotic or traditional open surgery. https://thejns.org/doi/abs/10.3171/2016.2.JNS15763
KEY WORDS bipolar electrocautery; endoscopic surgery; instrumentation; electrode; microscissor; microdissector; grasping forceps; surgical technique
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is an important tool in modern surgery that allows for precise tissue ablation and localized hemostatic control. Although widely used in traditional open operations, electrosurgery has been increasingly incorporated in endoscopic minimally invasive procedures, in which bipolar instruments are preferred to protect sensitive or critical anatomical structures. This form of electrosurgery is classically performed using a single bipolar instrument, which contains both an active and a return electrode.3,7 Traditional bipolar electrosurgical devices are dedicated 2-pronged forceps instruments that are held in 1 hand by the surgeon, inserted into the operating arena through a single access port, and maneuvered to the target site whenever cauterization is required.4 Although the traditional bipolar forceps design is effective for open surgical approaches, where access is readily available and pincer motion is relatively unrestricted, this design has many drawbacks in its application to minilectrosurgery
mally invasive and multiport surgeries. Dimensional and mobility constraints in these operations limit the use of forceps tips through small-diameter surgical corridors and negatively impact the application of bipolar electrosurgery. Because limited access points are available for surgeons to introduce instruments into the confined operating theater,5 primary surgical instruments—including suction devices, grasping forceps, dissectors, and scissors—must be temporarily removed and replaced by the electrosurgical forceps. This step prolongs operative duration and potentially increases the likelihood of postoperative infection or accidental tissue damage.6,9 Additionally, during standard 2-handed surgery the surgeon is limited to using only 1 additional surgical tool when using a dedicated electrosurgical instrument for cautery. Finally, maneuvering a single forceps instrument that opens strictly in a planar 2D field is challenging due to the limited depth perception and corridor restraints associated with endoscopic procedures.2,8
SUBMITTED April 4, 2015. ACCEPTED February 10, 2016. INCLUDE WHEN CITING Published online April 29, 2016; DOI: 10.3171/2016.2.JNS15763. ©AANS, 2017
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FIG. 1. Schematic illustration of the multiinstrument bipolar electrosurgical system. Traditional electrosurgery systems involve a single dedicated bipolar forceps probe with both active (+) and return (-) electrodes (left). The prototype design is shown with each electrode on a different instrument (right).
In this paper we describe a novel bipolar electrosurgical design in which independently functional endoscopic surgical instruments are insulated and electrically connected to serve as electrodes for a bipolar circuit and system. The technology works identically to a dedicated bipolar electrosurgical device by using a standard radiofrequency generator to establish an alternating current voltage across 2 metal contacts and induce tissue cauterization. The unique feature of this approach is that each electrode is represented by a different surgical instrument that maintains its original surgical function, thereby greatly increasing the mobility and efficiency of bipolar cautery for minimal-access as well as open surgery.
Methods
Instrument Description The prototype system (Fig. 1) was adapted from standard electrosurgical devices originally developed for endoscopic endonasal skull base surgery that were augmented to co-function as electrosurgical instruments. The shaft and handhold of these instruments were insulated and thereby rendered electrically inactive, with the exception of the electrically active metallic working instrument tip. The instrument tip then served its original function (e.g. microscissors, dissector) while additionally functioning as one of the electrodes of a bipolar electrosurgical circuit and system. A variety of methods for achieving adequate electrical insulation of the tool’s shaft could be considered, including epoxy, plastic, ceramic, or parylene deposition, as well as the creation of reusable or disposable instruments. For the purpose of this feasibility prototype experiment, electrical insulation of the instruments was achieved with epoxy and rubber coating.
Electrical current generated with a standard radiofrequency electrosurgical generator flowed through a modified plug affixed on the back of the surgical tool (Fig. 2) and the insulated shaft to reach the exposed working tip. Each instrument could be dually used: 1) in an independent fashion for its original function (i.e., microscissors, dissector, suction, and micrograspers); and 2) as a bipolar electrode when activated in conjunction with, and in apposition to, another instrument incorporated in the same electrical circuit. Any modular combination of 2 insulated instruments could be incorporated simultaneously in the electrosurgical circuit once equipped with a standard plug/wire connector. When the electrically active sites of these instruments are placed on a section of target tissue, the system could be activated by pressing on a standard foot pedal to induce the electrosurgical effect at the target tissue site. For this study, 5 prototype instruments functioning as a surgical system were developed to demonstrate surgical instrument functionality combined with electrosurgical capability: a microdissector, a grasping forceps, a suction tool, a ring curette, and a microscissors (Fig. 3). Prototype Used in Cadaveric Surgery This prototype electrosurgical design was first evaluated by reproducing a standard minimally invasive surgical procedure on 2 unpreserved human cadavers. Specifically, we used a binostril endonasal approach through two separate working corridors for an endoscopic transsphenoidal surgical approach commonly used for the resection of a pituitary tumor. The sphenoid sinus and sellar floor were widely exposed, and the dura overlying the pituitary gland was opened sharply. The electrosurgical prototypes were
FIG. 2. Schematic representation of an endoscopic surgical instrument converted into a single electrode for bipolar electrosurgery. 998
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FIG. 3. Examples of bipolar electrosurgical prototypes: microdissector (A), grasping forceps (B), and suction tool (C). Figure is available in color online only.
then introduced through separate nostrils under endoscopic guidance to approach the target region of the pituitary gland and operate as electrosurgical instruments. The 5 prototypes were used interchangeably for electrosurgical applications to demonstrate their capability for electrosurgery in addition to retaining their primary function. Representative images from the procedure to demonstrate the system’s function are shown in Figs. 4 and 5. Prototype Used in an In Vivo Rat Model This system was further evaluated through its use in carotid artery coagulation procedures performed on rats in an animal research laboratory. Two male retired breeder Sprague-Dawley rats weighing 750–800 g were used in this study. This rat was chosen because it has been used in prior studies as a model for testing vascular surgery, specifically in carotid artery coagulation.1 Animals were given a standard diet several days before the investigation and the animals were housed in accordance with National Research Council guidelines. Inhalant isoflurane (1%–4%) administered continuous-
ly through a nose cone was used to sedate each rat prior to the operation in accordance with animal care guidelines. Surgical carotid artery coagulation was first performed using traditional bipolar instruments and then using the prototype system. At the completion of the surgery, or when a humane endpoint was reached, the rats were killed with carbon dioxide treatment, and a thoracotomy was performed. Representative images and qualitative observations were recorded demonstrating the functionality of the system (Fig. 6).
Results
These feasibility experiments demonstrated that this system’s adapted surgical instruments can perform effective electrosurgery on target tissue while maintaining their original surgical uses. Endoscopic photographs from the endonasal transsphenoidal surgical approach demonstrate potential combinations of devices that were used with the novel electrosurgical system, thereby adding efficiency to the traditional surgical workflow for a variety of maneuvers. The electrically activated dissector and grasping
FIG. 4. Endoscopic view of transsphenoidal access to pituitary tissue in a human cadaver using the multiinstrument bipolar system. A: Grasping forceps and microdissector used to cauterize dura mater. B: Grasping forceps and suction tool used to cauterize the dura mater. C: Microdissector and suction tool used to cauterize vasculature. D: Suction and ring curette used to cauterize a simulated vascular tumor. Figure is available in color online only. J Neurosurg Volume 126 • March 2017
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FIG. 5. Electrosurgery performed with insulated surgical instruments increases surgical versatility and efficiency. Endoscopic view of transsphenoidal access to pituitary tissue in a human cadaver is shown using this multiinstrument bipolar system. The photographs show suction and microscissors used to cauterize and cut with rapid succession and obviating the need for instrument insertion and removal. Arrows indicate cauterized and cut dura with no instrument removal required (A) and cut vessel ends following electrocautery and microscissors application without instrument withdrawal (B). Figure is available in color online only.
forceps instruments were evaluated to demonstrate the function of cauterization and narrow localization of the cauterized tissue. Specifically, Fig. 4C demonstrates how a multiple instrument approach assists the surgeon in applying electrosurgery by allowing a multidirectional (i.e.,
nonplanar) approach to a small vascular target positioned deep in the surgical arena with improved visualization and independent mobility of each electrode instrument. During the human cadaveric dissection, we found that use of the novel electrocautery system could successfully be applied
FIG. 6. Electrosurgery performed in vivo in Sprague-Dawley rats demonstrating the prototype’s functionality in vascular coagulation/cautery with live suction and microscissors (A), grasping, cauterizing, and cutting tissue with grasping microforceps and microscissors (B), and “hot knife” cutting using the instrument as an electric scalpel in conjunction with grasping microforceps (C). Arrows indicate cut vessel ends following cautery (A) and cutting with microscissors without instrument removal (B). Figure is available in color online only. 1000
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TABLE 1. Potential advantages and limitations of novel, multifunctional, minimal-access electrosurgical system Advantages
Limitations
Improved visualization of surgical target given instrument approaches from various Potentially less accurate cautery at bipolar tips compared to working angles forceps Multifunctionality of instruments Possible need to interchange/plug-in modular instruments for desired multifunctional effect Smoke generated from cautery can be suctioned via adapted suction component Drop-off of thermal energy as a function of electrode tip distance Avoids constraints of forceps or planar opening/closing bipolar cautery Improves operative efficiency for microdissection Reduces instrument insertion/removal frequency
to minimally invasive endoscopic surgical approaches and add the additional benefit of cautery to the functions of the 2 instruments in use as part of this system (e.g., suction and miscroscissors). Live surgery performed in the rat model showed successful cautery of major arterial and venous structures using the system, with the added benefit of improved workflow gained by not having to remove and reintroduce instruments into the surgical field. Photographs from the in vivo experiment demonstrate the versatility of the prototype system and Fig. 6C specifically shows the efficacy of these instruments in hemostatic control. The varied approaches demonstrated in these figures depict how electrosurgery can be applied effectively from nontraditional electrode tips without requiring the pincer movement of a traditional bipolar forceps instrument. The combinations of various instruments provided maximal efficiency in workflow and reduced the requirements to remove and reinsert surgical devices when cautery was intermittently needed. Further unintended results included an ability to handle tissue while cauterizing, and suctioning of smoke and cautery byproducts when using the system, thereby improving visualization.
Discussion
Surgeons apply bipolar electrosurgery in minimally invasive surgical environments to perform precise operations, including hemostatic control and ligation.6,8 However, the use of these instruments in minimally invasive, endoscopic, multiport, and robotic surgery has been limited by the traditional design of the bipolar probes placed solely on standalone instruments. Our novel design for the application of bipolar electrosurgery augments the function of existing and validated surgical instruments and is intended to facilitate and augment any type of multiport, minimally invasive, and/or endoscopic, robotic, or even traditional open operations where a requirement for repeated cautery and tissue dissection, handling, and cutting is part of the surgical workflow (e.g., tumor resection or splitting the Sylvian fissure). The system functions as a set of modular and interchangeable dual-function instrument electrodes that are independently insulated, rather than a single bipolar cautery instrument with inherent design limitations in access, mobility, and depth perception as they pertain to endoscopic surgery. When used in combination with other instruments from the same system, bipolar electrosurgery may be applied using a variety
of multifunctional tips and using multiple surgical angles and approaches, rather than being confined to a single aperture as standard bipolar forceps currently are. The benefits of the proposed design are multifold (Table 1). First, it obviates the need for a single bipolar instrument that functions by grasping tissue only in a 2D planar field, which can be challenging when inserted through a single access port or when relying on 2D visualization on a video monitor. Second, the use of this prototype system obviates the requirement for a traditional electrosurgical forceps, which functions by opening and closing in a “pincer” movement, the motion of which is limited when operating through small apertures. Third, the design potentially increases surgical efficiency and enhances workflow by expanding the functions of standard surgical instrumentation to dually serve as bipolar components. Fourth, it facilitates the manipulation and cauterization of surgical tissue, which can be accessed by different instruments introduced through different surgical openings. Fifth, the design provides the additional benefit of being able to suction the smoke or other surgical byproducts resulting from electrocautery when one of the instruments is a suction device tip. And sixth, it increases surgical efficiency by minimizing the removal and insertion of surgical instruments, thereby potentially reducing the risk of direct tissue injury associated with repetitive removal/insertion, associated risks of infection, and potentially reducing operative duration.
Conclusions
In conclusion, surgical procedures performed on fresh cadaver tissue and in an in vivo rat model demonstrated that this novel multifunctional electrosurgical system has the capacity for improved mobility, visualization, and access of each bipolar electrode tip while preserving the intended function of each surgical instrument. We believe that this system may provide surgeons with a more efficient and versatile method of electrosurgery.
References
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and eye-hand coordination problems in laparoscopic surgery. Minim Invasive Ther Allied Technol 8:227–234, 1999 3. Cain RB, Patel NP, Hoxworth JM, Lal D: Abducens palsy after lumbar drain placement: a rare complication in endoscopic skull base surgery. Laryngoscope 123:2633–2638, 2013 4. Deatrick KB, Doherty GM: Power sources in surgery, in Doherty GM (ed): CURRENT Diagnosis & Treatment: Surgery, ed 14. New York: McGraw-Hill Education, 2015 5. Edmonson JM: History of the instruments for gastrointestinal endoscopy. Gastrointest Endosc 37 (2 Suppl):S27–S56, 1991 6. Kovaleva J, Peters FT, van der Mei HC, Degener JE: Transmission of infection by flexible gastrointestinal endoscopy and bronchoscopy. Clin Microbiol Rev 26:231–254, 2013 7. Lyson T, Sieskiewicz A, Sobolewski A, Rutkowski R, Kochanowicz J, Turek G, et al: Operative field temperature during transnasal endoscopic cranial base procedures. Acta Neurochir (Wien) 155:903–908, 2013 8. Minervini A, Siena G, Tuccio A, Lapini A, Serni S, Carini M: Sutureless hemostatic control during laparoscopic NSS for the treatment of small renal masses. Surg Innov 21:32– 38, 2014 9. Yao W, Childs PR: Application of design rationale for a robotic system for single-incision laparoscopic surgery and
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Disclosures
Dr. Zada owns the following US patents: 13/922000, nonprovisional (pending); and 14/508924, method claim (pending).
Author Contributions
Conception and design: Zada, Mittelstein, Deng. Acquisition of data: Mittelstein, Deng, Kohan, Sadeghi, Maarek. Analysis and interpretation of data: Mittelstein, Deng, Kohan, Sadeghi, Maarek. Drafting the article: Mittelstein. Critically revising the article: Zada, Mittelstein, Maarek. Reviewed submitted version of manuscript: Zada, Mittelstein, Maarek. Approved the final version of the manuscript on behalf of all authors: Zada. Administrative/technical/material support: Zada, Maarek. Study supervision: Zada, Maarek.
Correspondence
Gabriel Zada, Department of Neurosurgery, Keck School of Medicine, University of Southern California, 1200 N State St. #3300, Los Angeles, CA 90033. email:
[email protected].