Surg Endosc DOI 10.1007/s00464-013-3369-6

and Other Interventional Techniques

Laminar and turbulent surgical plume characteristics generated from curved- and straight-blade laparoscopic ultrasonic dissectors Fernando J. Kim • David Sehrt • Alexandre Pompeo Wilson R. Molina



Received: 26 August 2013 / Accepted: 29 November 2013 Ó Springer Science+Business Media New York 2014

Abstract Objective To characterize laparoscopic ultrasonic dissector surgical plume emission (laminar or turbulent) and investigate plume settlement time between curved and straight blades. Materials and methods A straight and a curved blade laparoscopic ultrasonic dissector were activated on tissue and in a liquid environment to evaluate plume emission. Plume emission was characterized as either laminar or turbulent and the plume settlement times were compared. Devices were then placed in liquid to observed consistency in the fluid disruption. Results Two types of plume emission were identified generating different directions of plume: laminar flow causes minimal visual obstruction by directing the aerosol downwards, while turbulent flow directs plume erratically across the cavity. Laminar plume dissipates immediately while turbulent plume reaches a second maximum obstruction approximately 0.3 s after activation and clears after 2 s. Turbulent plume was observed with the straight blade in 10 % of activations, and from the curved blade in 47 % of activations. The straight blade emitted less obstructive plume. Conclusion Turbulent flow is disruptive to laparoscopic visibility with greater field obstruction and requires longer settling than laminar plume. Ultrasonic dissectors with straight blades have more consistent oscillations and generate more laminar flow compared with curved blades. F. J. Kim (&)  D. Sehrt  A. Pompeo  W. R. Molina Division of Urology, Denver Health Medical Center, University of Colorado Cancer Center Denver (UCCCD), 777 Bannock St, MC0206, Denver, CO 80204, USA e-mail: [email protected] F. J. Kim  W. R. Molina University of Colorado Denver, Aurora, CO, USA

Surgeons may avoid laparoscope smearing from maximum plume generation depending on blade geometry. Keywords Laparoscopy  Image processing  Laminar  Surgical plume  Turbulent  Ultrasonic dissectors  Instrumentation

Surgical plume is an important yet understudied factor for surgical visibility during laparoscopic surgery [1–3]. Recently, we reported the quantification of surgical plume with ImageJ software [1]. In the previous experiment we noticed that not only is the amount of plume pivotal for optimal visibility but also for the direction of the plume generated. Therefore, we evaluated these characteristics of plume emission after activation of laparoscopic ultrasonic devices and investigated the effect from blade geometry.

Materials and methods Plume direction was studied under two categories of laparoscopic ultrasonic dissectors; straight- and curved-blade geometries. The Harmonic ACE (Ethicon Endo-Surgery Inc., Cincinnati, OH, USA) and the cordless Covidien Sonicision (Covidien, Mansfield, MA, USA) was representative of these two geometries. Each device was used on industry-specified coagulation modes during all activations. Surgical plume was identified with two modes of emission—laminar and turbulent. Laminar plume appears conical in shape (triangular in a side view) and is generated from a consistent source. Turbulent plume on the other hand has an irregular appearance, often containing a vortex, and is the result of rapid changes in pressure and velocity from the source (Fig. 1).

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Surg Endosc Fig. 1 Laminar emission with plume directed down and in a conical formation (left); turbulent emission with plume directed in a vortex (right)

Laminar and turbulent flow were evaluated in a ‘tissue’ and ‘liquid’ setting. The ‘Tissue’ setting quantified the settlement of plume following activation. Each blade geometry was activated on Bovine liver 30 times; the images were digitally captured and analyzed using the ImageJ software as previously described [1]. Plume was considered laminar if the maximum angle of the packet was \45° while the device was activated. The two types of emission were identified and the amount of obstruction and settlement time of plume were recorded. The ‘liquid’ setting studied the consistency of the blades relating to laminar and turbulent flow. All devices were activated after immersing the instrument into a 5-gallon Plexiglas container filled with normal sterile saline. The fluid disturbance along the blade was studied with frame-by-frame analysis in ImageJ using the same process. Disturbance patterns from the blades were identified and presented. Comparisons were made between laminar and turbulent flow datasets as well as curved and straight blades. Descriptive statistics were produced with the R Project version 2.11 (Wein, Australia). Data is presented as mean ± confidence intervals. Student’s t test and Fisher’s exact test were computed for all p-values. A pvalue \ 0.05 was considered statistically significant.

Results Laminar versus turbulent plume The ‘tissue’ experiment analyzed the effect of turbulent and laminar emission from the dissectors on plume settlement time. At the end of coagulation, turbulent plume had almost six times the amount of obstruction compared with laminar plume (p = 0.002) [Fig. 2]. Furthermore, turbulent plume resolved at half the rate of laminar plume using the exponential models (b = -0.04 vs. B = -0.09, respectively). Turbulent plume remained in suspension with a second peak at 0.3 s after activation of the device, and is dissipated after 2 s. Laminar plume immediately settled

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and completely dissipated within 1 s. Laminar plume has less of an obstruction on laparoscopic visibility than turbulent plume. Straight versus curved blade geometries Straight- and curved-blade geometries generated turbulent plume at different rates. The straight blade produced turbulent plume in 3/30 (10 %) activations, while the curved blade generated turbulent plume in 14/30 (47 %) activations (p = 0.003). The two blade geometries also generated different quantities of obstruction in laminar and turbulent plume (Fig. 2). The curved blade’s laminar plume obstructed 7.1 % of the laparoscopic field, while the straight blade’s plume obstructed 0.7 % (p \ 0.001). Comparing turbulent plume, the curved blade created an obstruction of 19.8 % of the field, while the straight blade obstructed 4.4 % of the field (p = 0.004). Furthermore, the curved blade’s turbulent plume requires [2 s to clear the field, while the straight blade’s field is cleared in 1.3 s. Overall, a straight blade generates less obstruction due to plume than a curved blade. The ‘fluid’ study revealed a similar set of results as those observed in the ‘tissue’ model. The Sonicision generated a single pattern of fluid disturbance. The only pattern consisted of two focal disturbances at the top and bottom of the distal portion of the blade (Fig. 3). This was an indication of fluid being directed in the longitudinal direction parallel with the blade’s vibration. The curved blade revealed similar emission at the distal tip, with additional inconsistent vibrations along the sides of the blade indicating lateral motion.

Discussion Plume emission during laparoscopic surgery has been the constant nemesis of surgeons. Laparoscopic surgery has shown to be more stressful than open surgery, and poor visibility may increase operating time by removing scopes

Surg Endosc Fig. 2 The average percentage of obstruction by plume versus time in A coagulation mode; B from a straight blade; and C from a curved blade

Fig. 3 Fluid disturbance from the straight and curved blades. (Top) The straight blade exhibits fluid disturbance at the distal portion of the blade (left, middle, and right). (Bottom) The curved blade exhibits fluid disturbance at the distal end of the blade and on both sides of the blade (left), solely at the distal end (middle), and at the distal end and the inner curvature of the blade (right)

from the working cavity to clean the lenses, affecting surgeons’ frustration, and it may increase procedure morbidity [4]. The characterization and better understanding of plume formation and emission by laparoscopic ultrasonic devices has been our interest, so the surgeon may opt for different designs of instrumentations, understanding ways to minimize frustrating occurrences with decreased visualization due to plume formation.

Flow (laminar and turbulent) can be determined by the consistency of the source and by the Reynolds number (Re). The Reynolds number compares the amount of kinetic energy in the system to the work of viscous forces [5]. As the Reynolds number increases, emission transitions from laminar to turbulent. The Reynolds number is mathematically described as Re = ULq/m, where q is the density of the fluid, U is the velocity, L is the length of the

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domain, and m is the viscosity of the fluid. The two primary factors to influence the Reynolds number in plume emission are the velocity (U) and initial width (L). The velocity of emission is thought to be related to the speed of the blade. All ultrasonic devices rely on simple harmonic motion of the titanium blade to cut and coagulate tissue [6]. The velocity of the simple harmonic motion of the blade is defined by the formula: V ¼ A  2pF  cosð2pFtÞ; where V is velocity, A is the amplitude, F is the frequency, and t is time [7]. Manufacturers can vary the frequency and maximum amplitude control the degree of coagulation and cutting. However, these two instruments operate at a similar frequency (55.5 kHz) and a maximum amplitude (*100 lm). The velocities of each blade should be considered standardized in this experiment and may not contribute to the difference in plume obstruction. Another device previously studied operated a lower frequency (47.5 kHz) and was found to generate less plume [1]. The other factor influencing plume direction is the width of the plume, which is influenced by the geometry of the blade. There were two fundamental blade geometries in the studied devices—straight and curved. The straight blade’s motion is simplest, with motion occurring only in the longitudinal direction along the blade. The curved blade exhibits motion along the longitudinal and possibly lateral directions. The curved blade may increase the contact area with tissue during activation, as seen in the lateral displacement along the blade in the fluid study. This lateral displacement would increase the width of the plume produced, thus increasing the Reynolds number and the turbulent emission. Compounded with inconsistent pressure on tissue as the blade’s vibrations translate along the blade, this would generate a broad range of plume momentum causing turbulent flow. The straight blade commonly produced laminar flow, indicating a focused contact area with consistent pressure on tissue during activation. Optimization of visibility during laparoscopic surgery is pivotal for a successful and safe procedure [8]. The production and dissipation of plume affects visibility. The large field of plume production and slow dissipation generated by turbulent plume and curved blades should be considered when operating the scope. We used the same ‘tissue’ model reported for the plume analysis and successfully applied our imaging technique to our ‘liquid’ model [1]. Understanding the mechanisms of plume formation and direction could minimize visibility issues when applying these different instruments. We

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observed that the patterns of emissions were distinctively different. These observations triggered the characterization of plume emission in terms of direction and type of disturbance. Our studies demonstrate a significant difference in plume obstruction between ultrasonic blade geometries.

Conclusion Plume emission with turbulent flow is disadvantageous to laparoscopic visualization, even after blade activation. Straight blades typically generate laminar plume with minimal obstruction and fast dissipation from the field. Curved blades cause turbulent plume more often, with slower dissipation affecting laparoscopic visibility. Acknowledgments

None.

Disclosures Fernando J. Kim is a principal investigator for Olympus, Covidien, Healthtronics, Amgem, and Cubist. Wilson R. Molina has a fellowship grant with Boston Scientific. David Sehrt and Dr. Rodrigo da Silva have no conflicts of interest or financial ties to disclose. Funding

This article was self-supported.

References 1. Kim FJ, Sehrt D, Pompeo A, Molina WR (2012) Comparison of surgical plume among laparoscopic ultrasonic dissectors using a real-time digital quantitative technology. Surg Endosc 26:3408– 3412 2. Weld KJ, Dryer S, Ames C, Cho K, Hogan C, Lee M, Biswas P, Landman J (2007) Analysis of surgical smoke produced by various energy-based instruments and effect on laparoscopic visibility. Surg Endosc 3:347–351 3. Schneider A, Doundoulakis E, Can S, Fiolka A, Wilhelm D, Feussner H (2009) Evaluation of mist production and tissue dissection efficiency using different types of ultrasound shears. Surg Endosc 23:2822–2826 4. Van Det M, Meijerink W, Hoff C, Totte E, Pierie J (2009) Optimal ergonomics for laparoscopic surgery in minimally invasive surgery suites: a review and guidelines. Surg Endosc 23:1279–1285 5. Batchelor G (2000) Introduction to fluid mechanics. Cambridge University Press, Cambridge 6. Gossot D, Buess G, Cuschieri A, Leporte E, Lirici M, Marvik R, Meijer D, Melzer A, Schurr MO (1999) Ultrasonic dissection for endoscopic surgery. Surg Endosc 13:412–417 7. Cimino W, Bond L (1996) Physics of ultrasonic surgery using tissue fragmentation: part I. Ultrasound Med Biol 1:89–100 8. Uhrich ML, Underwood RA, Standeven JW, Soper NJ, Engsberg JR (2002) Assessment of fatigue, monitor placement, and surgical experience during simulated laparoscopic surgery. Surg Endosc 16:635–639

Laminar and turbulent surgical plume characteristics generated from curved- and straight-blade laparoscopic ultrasonic dissectors.

To characterize laparoscopic ultrasonic dissector surgical plume emission (laminar or turbulent) and investigate plume settlement time between curved ...
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