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Harmonic scalpel tonsillectomy: Technical considerations
HARMONIC SCALPEL TONSILLECTOMY: TECHNICAL CONSIDERATIONS ASHKAN MONFARED, BS, DAVID J. TERRIS, MD
Among the latest innovations in the field of otolaryngology is the application of ultrasonically-activated instruments such as the Harmonic scalpel (Ethicon Endosurgery, Cincinnati, OH) to tonsillectomy. Preliminary reports have suggested that the Harmonic scalpel might represent the much pursued compromise between the precision and fast healing of the cold scalpel and the lower postoperative bleeding risk of electrocauteryJ It is worth acquiring an understanding of this new technology; we will subsequently describe our surgical technique and consider the potential advantages as well as the limitations of the Harmonic scalpel compared to conventional methods of tonsillectomy.
TECHNOLOGICAL CONSIDERATIONS The Harmonic scalpel (HS) technology is based on rapid longitudinal vibrations of the blade at 55000 Hz over a distance of 50 >m to 100/,m. The vibrations are produced by the expansion and contraction of piezoelectric crystals in the hand piece of the scalpel that are transferred to the tip via the blade extenders. The mechanical vibration is applied to the tissue, and the "frictional" energy denatures the proteins by breaking the hydrogen bonds at temperatures of between 50~ and 100~ There is no electrical current involved. The HS has power settings of 1 through 5 that dictate the distance that the blade will travel at the same speed. The lower settings (longer excursion of the blade) are optimal for operations demanding maximum coagulation, and the higher settings (shorter excursion of the blade) are preferred for cutting through avascular tissue. At all settings, the foot pedal offers two blade speeds of "full" and "variable," which are used for cutting and coagulation, respectively. The harmonic scalpel offers a variety of blades in differing handle lengths.
SURGICAL TECHNIQUE Patient positioning, delivery of anesthesia, and placement of the mouth retractors are identical to conventional methods of tonsillectomy (Fig 1). The HS is held like a cold knife, and the tonsil is retracted medially using an Allis clamp (Fig 2A). A hook blade on a 10 cm handle at a power setting of 3 has proven to be optimal for tonsillectomy operations (Fig 2B). Starting from the superior portion of the anterior tonsillar pillar (mucosal covering of the palatoglossus muscle), the plane of dissection is defined between the tonsillar capsule and the tonsillar bed. As in conventional tonsillectomy, every effort is made to miniFrom the Department of Otolaryngology/Head and Neck Surgery, Medical College of Georgia, Augusta, GA. Address reprint requests to David J. Terris, MD, FACS, Department of Otolaryngology-Head and Neck Surgery, Medical College of Georgia, 1120 Fifteenth Street, Augusta, GA 30912-4060. E-mail: [email protected]. Copyright 2002, Elsevier Science (USA). All rights reserved. 1043-1810/02/1302-0010535.00/0 doi:l 0.1053/otot.2002.125987
mize the amount of mucosa resected. Because of its minimal lateral thermal dissipation, larger vessels are not as easily coagulated with the HS as with monopolar electrocautery. For this reason, it is imperative to gently move the blade laterally and medially while advancing parallel to the tonsillar capsule to minimize bleeding. In highly vascular areas, such as the inferior aspect of the anterior and posterior tonsillar pillars, the blade should be advanced very slowly on the "variable" setting in order to coagulate the blood vessels. In the event of bleeding, the flat part of the blade is gently applied for several seconds using the "variable" mode (Fig 3A and 3B). A white coagulum coats the fossae after the tonsils are removed, but char is conspicuously absent. It is important to understand that unlike the electrocautery that is only effective on tissue that has been grounded, the HS will cut any object with which it comes in contact. In a case reported by Hayakawa et al, 2 the thin tube connected to the cuff of the endotracheal tube was inadvertently severed by the blade which resulted in a potentially hazardous leak around the tube. Additionally, all parts of the blade are ultrasonically active, so care must be taken to avoid unintentional tissue contact.
DISCUSSION ADVANTAG
ES
Several authors have recently compared the HS to conventional technique for tonsillectomy. In a prospective study comparing patients w h o have undergone tonsillectomy by the HS versus by electrocautery, Walker and Syed 1 found that a higher percentage of patients in the HS group were able to ingest food 24 hours and 72 hours postoperatively. The same study demonstrated that the postoperative use of analgesics was similar in both groups. Finally, there was no statistically significant difference between the perioperative and postoperative bleeding b e t w e e n the two groups. Compared to the blunt dissection method, the HS was shown by another group to cause significantly less intraoperative and immediate postoperative pain. However, when compared over a 2-week period, otalgia and pharyngeal pain were significantly higher in the HS group. 3
OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEAD AND NECK SURGERY, VOL 13, NO 2 (JUN), 2002: P 155-157
155
.... q
FIGURE 1. The patient is positioned as for a traditional tonsillectomy, with a mouthgag of choice positioned to obtain exposure of the oropharynx. Placement of a grounding pad is not required, as no electric current is involved in the delivery of energy with the Harmonic scalpel.
FIGURE 2. (A) The tonsil is retracted medially, placing the tissues on tension. (B) The Harmonic scalpel is then turned to a setting of 3, on the "full" mode, and the anterior pillar mucosa is divided, exposing the tonsillar capsule. Dissection continues in this plane, as for a traditional tonsillectomy.
Arguably the major advantage of ultrasonically-activated instrumention is the lesser lateral thermal injury compared to the electrocautery. It has been demonstrated that the lateral thermal injury caused b y the HS is 0 tzm to 1000 ~m compared to between 240 ~m and 15 mm by the electrocautery. 4 LI M I T A T I O N S
The procedure time for a HS tonsillectomy is somewhat longer than for electrocautery. However, this may be related to some extent to the steep learning curve associated with the HS. 1'5 For instance, in one study comparing the HS and electrocautery, the surgeons initially used the electrocautery to control bleeding in the HS group. ~ Once surgeons become familiar with the technique and the capabilities of the HS, the operation time becomes comparable to that for monopolar electrocautery tonsillectomy. The preparation time of the two instruments is comparable. The plane of dissection is somewhat easier to define when using electrocautery, in which the electrical current easily divides the tissue under tension. The white coagulure produced by the HS has a tendency to obscure the tissue planes. Although the HS does not produce any char or smoke, this advantage of the HS is diminished when comparing it to electrocautery if the coagulation mode is used judiciously.
156
FIGURE 3. (A-B) Modest bleeding can be controlled by holding the blade against the tissues, and activating the "variable" footpedal. Hemostasis may require several seconds of energy delivery.
HARMONIC SCALPEL TONSILLECTOMY
....7 1 1 ; iii!ii!i;iii!:!iiiii~? / ~ I I ? L ~
CONCLUSION Preliminary data has d e m o n s t r a t e d that the HS p r o v i d e s s o m e m o d e s t benefits w h e n c o m p a r e d to electrocautery for tonsillectomy. While t w o m a j o r a d v a n t a g e s of HS (lesser lateral thermal injury a n d absence of char and smoke) m a y be m o r e relevant in other surgical sites (as for endoscopic neck surgery), it has b e e n s h o w n that patients return to a regular diet a n d activity earlier w h e n the HS is u s e d to p e r f o r m a tonsillectomy. Whether such a d v a n tages are sufficient to justify w i d e s p r e a d a d o p t i o n of this technology for tonsillectomy w a r r a n t s further investigation.
REFERENCES
qr
FIGURE 4. The appearance of the tonsillar fossae after Harmonic scalpel tonsillectomy; char is conspicuously absent, while the bed is typically coated with a white coagulum.
MONAFRED AND TERRIS
1. Walker RA, Syed ZA: Harmonic scalpel tonsillectomy versus electrocautery tonsillectomy: A comparative pilot study. Otolaryngol Head Neck Surg 125:449455, 2001 2. Hayakawa M, Morimoto Y, Kemmotsu O: Tracheal tube damage by Harmonic Scalpel during tonsillectomy [in Japanese]. Masui 49:12611262, 2000 3. Akural EI, Koivunen PT, Teppo H, et al: Post-tonsillectomy pain: a prospective, randomized and double-blinded study to compare an ultrasonically activated scalpel technique with the blunt dissection technique. Anaesthesia 56:1045-1050, 2001 4. McCarus SD: Physiologic mechanism of the ultrasonically activated scalpel. J Am Assoc Gynecol Laparosc 3:601-608, 1996 5. Sood S, Corbridge R, Powles J, et al: Effectiveness of the ultrasonic harmonic scalpel for tonsillectomy. Ear Nose Throat J 80:514-516, 2001
157
Among the latest innovations in the field of otolaryngology is the application of ultrasonically-activated instruments such as the Harmonic scalpel (Ethicon Endosurgery, Cincinnati, OH) to tonsillectomy. Preliminary reports have suggested that the Harmonic scalpel might represent the much pursued compromise between the precision and fast healing of the cold scalpel and the lower postoperative bleeding risk of electrocauteryJ It is worth acquiring an understanding of this new technology; we will subsequently describe our surgical technique and consider the potential advantages as well as the limitations of the Harmonic scalpel compared to conventional methods of tonsillectomy.
TECHNOLOGICAL CONSIDERATIONS The Harmonic scalpel (HS) technology is based on rapid longitudinal vibrations of the blade at 55000 Hz over a distance of 50 >m to 100/,m. The vibrations are produced by the expansion and contraction of piezoelectric crystals in the hand piece of the scalpel that are transferred to the tip via the blade extenders. The mechanical vibration is applied to the tissue, and the "frictional" energy denatures the proteins by breaking the hydrogen bonds at temperatures of between 50~ and 100~ There is no electrical current involved. The HS has power settings of 1 through 5 that dictate the distance that the blade will travel at the same speed. The lower settings (longer excursion of the blade) are optimal for operations demanding maximum coagulation, and the higher settings (shorter excursion of the blade) are preferred for cutting through avascular tissue. At all settings, the foot pedal offers two blade speeds of "full" and "variable," which are used for cutting and coagulation, respectively. The harmonic scalpel offers a variety of blades in differing handle lengths.
SURGICAL TECHNIQUE Patient positioning, delivery of anesthesia, and placement of the mouth retractors are identical to conventional methods of tonsillectomy (Fig 1). The HS is held like a cold knife, and the tonsil is retracted medially using an Allis clamp (Fig 2A). A hook blade on a 10 cm handle at a power setting of 3 has proven to be optimal for tonsillectomy operations (Fig 2B). Starting from the superior portion of the anterior tonsillar pillar (mucosal covering of the palatoglossus muscle), the plane of dissection is defined between the tonsillar capsule and the tonsillar bed. As in conventional tonsillectomy, every effort is made to miniFrom the Department of Otolaryngology/Head and Neck Surgery, Medical College of Georgia, Augusta, GA. Address reprint requests to David J. Terris, MD, FACS, Department of Otolaryngology-Head and Neck Surgery, Medical College of Georgia, 1120 Fifteenth Street, Augusta, GA 30912-4060. E-mail: [email protected]. Copyright 2002, Elsevier Science (USA). All rights reserved. 1043-1810/02/1302-0010535.00/0 doi:l 0.1053/otot.2002.125987
mize the amount of mucosa resected. Because of its minimal lateral thermal dissipation, larger vessels are not as easily coagulated with the HS as with monopolar electrocautery. For this reason, it is imperative to gently move the blade laterally and medially while advancing parallel to the tonsillar capsule to minimize bleeding. In highly vascular areas, such as the inferior aspect of the anterior and posterior tonsillar pillars, the blade should be advanced very slowly on the "variable" setting in order to coagulate the blood vessels. In the event of bleeding, the flat part of the blade is gently applied for several seconds using the "variable" mode (Fig 3A and 3B). A white coagulum coats the fossae after the tonsils are removed, but char is conspicuously absent. It is important to understand that unlike the electrocautery that is only effective on tissue that has been grounded, the HS will cut any object with which it comes in contact. In a case reported by Hayakawa et al, 2 the thin tube connected to the cuff of the endotracheal tube was inadvertently severed by the blade which resulted in a potentially hazardous leak around the tube. Additionally, all parts of the blade are ultrasonically active, so care must be taken to avoid unintentional tissue contact.
DISCUSSION ADVANTAG
ES
Several authors have recently compared the HS to conventional technique for tonsillectomy. In a prospective study comparing patients w h o have undergone tonsillectomy by the HS versus by electrocautery, Walker and Syed 1 found that a higher percentage of patients in the HS group were able to ingest food 24 hours and 72 hours postoperatively. The same study demonstrated that the postoperative use of analgesics was similar in both groups. Finally, there was no statistically significant difference between the perioperative and postoperative bleeding b e t w e e n the two groups. Compared to the blunt dissection method, the HS was shown by another group to cause significantly less intraoperative and immediate postoperative pain. However, when compared over a 2-week period, otalgia and pharyngeal pain were significantly higher in the HS group. 3
OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEAD AND NECK SURGERY, VOL 13, NO 2 (JUN), 2002: P 155-157
155
.... q
FIGURE 1. The patient is positioned as for a traditional tonsillectomy, with a mouthgag of choice positioned to obtain exposure of the oropharynx. Placement of a grounding pad is not required, as no electric current is involved in the delivery of energy with the Harmonic scalpel.
FIGURE 2. (A) The tonsil is retracted medially, placing the tissues on tension. (B) The Harmonic scalpel is then turned to a setting of 3, on the "full" mode, and the anterior pillar mucosa is divided, exposing the tonsillar capsule. Dissection continues in this plane, as for a traditional tonsillectomy.
Arguably the major advantage of ultrasonically-activated instrumention is the lesser lateral thermal injury compared to the electrocautery. It has been demonstrated that the lateral thermal injury caused b y the HS is 0 tzm to 1000 ~m compared to between 240 ~m and 15 mm by the electrocautery. 4 LI M I T A T I O N S
The procedure time for a HS tonsillectomy is somewhat longer than for electrocautery. However, this may be related to some extent to the steep learning curve associated with the HS. 1'5 For instance, in one study comparing the HS and electrocautery, the surgeons initially used the electrocautery to control bleeding in the HS group. ~ Once surgeons become familiar with the technique and the capabilities of the HS, the operation time becomes comparable to that for monopolar electrocautery tonsillectomy. The preparation time of the two instruments is comparable. The plane of dissection is somewhat easier to define when using electrocautery, in which the electrical current easily divides the tissue under tension. The white coagulure produced by the HS has a tendency to obscure the tissue planes. Although the HS does not produce any char or smoke, this advantage of the HS is diminished when comparing it to electrocautery if the coagulation mode is used judiciously.
156
FIGURE 3. (A-B) Modest bleeding can be controlled by holding the blade against the tissues, and activating the "variable" footpedal. Hemostasis may require several seconds of energy delivery.
HARMONIC SCALPEL TONSILLECTOMY
....7 1 1 ; iii!ii!i;iii!:!iiiii~? / ~ I I ? L ~
CONCLUSION Preliminary data has d e m o n s t r a t e d that the HS p r o v i d e s s o m e m o d e s t benefits w h e n c o m p a r e d to electrocautery for tonsillectomy. While t w o m a j o r a d v a n t a g e s of HS (lesser lateral thermal injury a n d absence of char and smoke) m a y be m o r e relevant in other surgical sites (as for endoscopic neck surgery), it has b e e n s h o w n that patients return to a regular diet a n d activity earlier w h e n the HS is u s e d to p e r f o r m a tonsillectomy. Whether such a d v a n tages are sufficient to justify w i d e s p r e a d a d o p t i o n of this technology for tonsillectomy w a r r a n t s further investigation.
REFERENCES
qr
FIGURE 4. The appearance of the tonsillar fossae after Harmonic scalpel tonsillectomy; char is conspicuously absent, while the bed is typically coated with a white coagulum.
MONAFRED AND TERRIS
1. Walker RA, Syed ZA: Harmonic scalpel tonsillectomy versus electrocautery tonsillectomy: A comparative pilot study. Otolaryngol Head Neck Surg 125:449455, 2001 2. Hayakawa M, Morimoto Y, Kemmotsu O: Tracheal tube damage by Harmonic Scalpel during tonsillectomy [in Japanese]. Masui 49:12611262, 2000 3. Akural EI, Koivunen PT, Teppo H, et al: Post-tonsillectomy pain: a prospective, randomized and double-blinded study to compare an ultrasonically activated scalpel technique with the blunt dissection technique. Anaesthesia 56:1045-1050, 2001 4. McCarus SD: Physiologic mechanism of the ultrasonically activated scalpel. J Am Assoc Gynecol Laparosc 3:601-608, 1996 5. Sood S, Corbridge R, Powles J, et al: Effectiveness of the ultrasonic harmonic scalpel for tonsillectomy. Ear Nose Throat J 80:514-516, 2001
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