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Ultrasonic Devices in Cardiac Surgery

Department of Cardiac Surgery St. John's Hospital Salzburg, Austria

For reprint information contact: Probal Ghosh, FRCS, FETCS Tel: 43 662 4482 3353 Fax: 43 662 43 3840 email: probalg{at}hotmail.com Department of Cardiac Surgery, St. John's Hospital, Muellner Hauptstrasse 48, Salzburg A5020, Austria.

	Abstract

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 
Recent innovations in ultrasonic devices include high-frequency coagulating shears with piezoelectric ceramic electrostrictive transducers for both open and endoscopic procedures. Various ultrasonic devices have been used for the dissection of internal mammary, radial, and gastroepiploic arteries, aortic root, proximal right coronary artery, and left main coronary artery, as well as prior to surgical coronary ostial reconstruction and for elimination of stenotic induration in coronary arteries, release of muscle bridges, exposure of deep-seated coronary arteries, pericardiectomy, and removal of a cardiac tumor. Unlike valve decalcification, the required energy output of ultrasonic aspirators in coronary artery surgery is much lower and harvesting time of arterial conduits is significantly shortened. Ultrastructural studies of harvested internal mammary artery segments with scanning and transmission electron microscopy revealed no structural alteration of the wall or luminal surface when low energy output was used for dissection. On direct application of higher energy, subendothelial blistering may be detected occasionally. Ultrasonic devices help to remove thick fatty tissue and muscle bridges with almost no bleeding. Use of these devices may facilitate precise coronary artery surgery.

	Introduction

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 
The first use of an ultrasonic device in cardiac surgery was 27 years ago.¹ Current use of these devices in cardiovascular surgery has developed mostly in the last decade.^2–21 Earlier, water-cooled ultrasonic aspirators with magnetostrictive transducers were used to fragment and aspirate calcium, fat, and soft tissues. Subsequently, ultra-sonic aspirators were modified, employing a piezoelectric ceramic electrostrictive transducer that required no cooling and these have been used in coronary artery surgery.^13,14 Ultrasonic coagulating shears have now been introduced into cardiac surgery.^15–20 Various frequencies of ultrasound have also been used for intravascularng (20 to 40MHz, usually 30 MHz) and extravascular imaging (3.5 to 12 MHz) in coronary artery disease and for assessing internal mammary artery (IMA). Mechanical scanning using ultrasound at 7.5 MHz has been used for trans-cutaneous measurement of IMA flow. Catheter-delivered ultrasonic devices usually operate at 20 kHz, whereas surgical ultrasonic devices use higher frequencies.

	Magnetostrictive Aspirators

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 
Ultrasonic waves can be produced by applying electro-magnetic energy to a magnetostrictive transducer that produces mechanical vibration in response to a magnetic field. Traditionally, such devices have been identified with the commercially successful ultrasonic aspirator introduced by Cavitron (Valley Lab, Denver, CO, USA) and often referred to as CUSA. Other devices employing the same principles are Ultra ultrasonic aspirators (Sharplan Lasers, Inc., Needham, MA, USA), Sonotec ME 2000 and ME 2100 (Sumitomo Corp., Tokyo, Japan) and Dr. Loschilov's URSK7N (developed in Moscow, Russia, and reported from Moscow and Kaunas, Lithuania).^2–9 These ultrasonic aspirators (USAs) vibrate at 23 kHz to fragment tissue and they require coaxial irrigation with a powerful aspiration device to remove cellular debris and water. A tip-cooling system is essential. The collagen-rich tissues of nerves, blood vessels, and lymphatics are usually left intact. These devices have also been generically termed ultrasonic cavitation aspirators (UCA).

	Electrostrictive Aspirators

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 
Electrostrictive aspirators produce ultrasonic waves using a piezoelectric transducer. They usually vibrate at 23 to 26 kHz. The commercially available devices are Sonocor (Soring, Quickborn, Germany) and Sonocut Maxi C-1000 (Swedemed, Uppsala, Sweden). At higher energy output, these devices also coagulate similar to monopolar diathermy. These USAs consist of a pencil-grip handpiece connected by a long cable to a central console and a control pedal. The hollow conical titanium tip of the handpiece vibrates at 23 to 26 kHz along its axis with longitudinal waves when activated by an electrostrictive piezoelectric ceramic transducer encased within the handpiece (Figure 1). The maximum range of vibration is 370 microns and it can be adjusted to different settings from the central console. Maximum power available is 100 W. As the piezoelectric dipolar molecules from lead, zirconium, and tantalum in ceramic are used in this transducer, loss of energy in the form of heat is avoided to a great extent, in contrast to the commercially available UCA with magnetostrictive transducers. Consequently, no separate cooling is required, the titanium tip retains a longer life-span (150 to 200 hours), and almost 95% energy efficiency is available at the tip. The handpiece with the connecting cable can be sterilized by autoclaving at 137°C for 15 minutes. The handpiece is continuously irrigated with normal saline through the ducts contained within. The flow rate of the irrigant can be controlled from 0 to 60 mL•min^–1 by a roller pump in the central console. A suction line connected to the tip aspirates the irrigant, fragmented tissue, calcium, and blood. Aspiration pressure can be controlled from 0 to 800 mbar from the central console that also houses the electronic circuitry for computer regulation of all functions. The control pedal works on an on/off basis and serves to trigger irrigation and aspiration. The adjustment of the vibration settings in the central console is critical. At the lowest settings, tissue with a high water content (fat, areolar parenchyma) is fragmented and aspirated, while tissue with elastin or collagen (arteries) are spared. Thus, the small vascular branches are left intact and can be ligated and divided. At higher settings, all tissues are disrupted and the vessels can be torn or damaged. The use of these devices per se is not hemostatic. Their ability to aspirate fat and surrounding parenchyma to expose the small branches precisely without injury helps in securing small vessels and reducing blood loss and dissection time.

View larger version (16K): [in this window] [in a new window]   Figure 1. Schematic diagram of electrostrictive ultrasonic aspirator.

	Ultrasonic-Activated Scalpels

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

View larger version (5K): [in this window] [in a new window]   Figure 2. Schematic diagram of ultrasonically activated scalpel handpiece for open surgery.

View larger version (8K): [in this window] [in a new window]   Figure 3. Schematic diagram of ultrasonically activated scalpel handpiece for thoracoscopic surgery.

	Cardiac Surgical Applications

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 
Internal mammary artery conduit has been prepared either as a pedicle or skeletonized using ultrasonic devices. The UCA should be used with low energy output (up to 10%) to dissect fat and connective tissues. Small branches of the IMA are exposed, clipped, and divided. The rates of irrigation and aspiration are both kept low to avoid injury to branches and the IMA wall and care must be taken to keep the titanium tip of the device away from the IMA while dissecting.^3,5,13,14 The Harmonic Scalpel has been used for both open and thoracoscopic harvesting of IMA.^14,18 This device has also been used for open harvesting of radial and gastroepiploic arterial conduits.^18–23 When graft sites in coronary arteries are deeply embedded, USAs have been used before clamping the aorta for exposure of the left anterior descending, diagonal, obtuse marginal, posterior descending, and posterolateral coronary arteries.^13,14 The Harmonic Scalpel has been used on a beating heart to expose such arteries.²⁴ Both the left main and proximal right coronary arteries have been dissected for coronary ostial reconstruction using USAs at 10% energy output. For vein-patch reconstruction of the right ostium and the proximal right coronary artery, the stenotic induration of the right coronary artery wall revealed after arteriotomy was eliminated using USAs at 25% energy output but with a high irrigation rate. Similar to mitral and aortic valve decalcification (conducted in another series of patients), a higher rate of irrigation and aspiration was necessary for efficacy and safety of the procedure. Left anterior descending coronary artery obstructions by muscle bridges have been relieved by USAs at high energy output, which exposed the buried artery with practically no bleeding. Even small venous tributaries running directly over the artery were identified separately, secured, and divided.^6,13,20

The first application of an ultrasonic aspirator in cardiac surgery was for debridement of calcified aortic stenosis.¹ Both in-vitro and in-vivo decalcification of valve leaflets and annuli have been performed with CUSA, Sonocor, and other devices.^7–10 Renewed clinical interest in ultrasonic debridement, especially in senile aortic valve disease, in several centers in the late 1980s and early 1990s, led to satisfactory early results in reduction of transvalvular gradients but disappointing late outcome due to aortic cuspal retraction and progressive aortic regurgitation.^25–34 Such changes may be due to a higher ultrasonic power setting and aggressive application for longer duration. Current majority opinion favors ultrasonic application for aortic annular decalcification only prior to aortic valve replacement. Similarly, ultrasonic debridement facilitates superior and expedient mitral annular de-calcification.^35–40 It helps in mitral valve reconstruction and chordae-sparing mitral valve replacement.^35–40 It may be advisable to avoid using the Harmonic Scalpel for decalcification.

USAs have been helpful for dissection in redo coronary surgery and pericardiectomy in constrictive pericar-ditis.^12,16,41,42 They have also been used successfully to dissect out capillary hemangioma of the right atrio-ventricular groove in a 6-week-old infant.⁴³ Thus, in coronary artery surgery, especially in the dissection of IMA grafts and exposure of deeply embedded coronary arteries, USAs reduce operative time and facilitate localization. As in the case of optical magnification, they have definitely improved the ease and precision of surgery.

	Effects of Ultrasonic Devices

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 
Evaluation of any surgical device should consider primary outcome determinants such as dissection time, blood loss, reproducibility, and ease of dissection, as well as secondary determinants including tissue effects, and prevention of complications (for example, reexploration). Dissection time, retrosternal bleeding during dissection, and the free flow of IMA grafts in conventional surgery have been compared with the same parameters in patients treated with ultrasonic devices. Harvesting time was found to be significantly shorter with USAs, after the learning curve. No trauma or hematoma of IMA grafts was noticed in the USA-treated group. The device especially facilitated skeletonized dissection of IMA grafts. However, no statistical difference was found in blood loss or IMA free flow between the two groups.

Tissue effects of ultrasonic aspirators are caused by 4 factors: mechanical vibration causing fragmentation; cavitation; thermal energy; and formation of intracellular microcurrents.¹ Creation and subsequent collapse of vapor-filled micro-bubbles in cells, fluids, and tissues, accom-panied by local intense hydraulic shock, result in a cavitation effect, generating up to 3 atmospheres of pressure at the site of contact and disruption of the target tissue. Ultrastructural studies with scanning electron microscopy (SEM) and transmission electron microscopy assessed the effects of different levels of energy output of USAs.¹⁴ SEM at low magnification revealed no serious defect in the luminal surface of IMA segments from conventional surgery with electrocautery or the use of ultrasonic aspirators. High-magnification SEM in the electrocautery group showed that the endothelium was intact; slender spindle-shaped endothelial cells were oriented parallel to the long axis of the vessel. In one specimen from the electrocautery group, numerous small shallow pits and crater-like changes were noticed, suggesting endothelial disturbance. Similarly, in the USA-treated group, high-magnification SEM showed normal endothelium but a few areas of endothelial denudation with platelets adherent to the exposed basement membrane were seen in one specimen. However, these areas were very few in number and small in size. Transmission electron microscopy revealed well-preserved wall structures of the media and adventitia of the IMA segments in both groups. In the electrocautery group, the intimal endothelium remained closely attached to the sub-endothelial matrix. In the USA-treated group, specimens directly exposed to a high energy output (25 W) showed striking subendothelial blistering. Terada and colleagues⁴⁴ also noticed severe intimal damage if the tip of the device came in direct contact with the arterial wall even for a short while. In contrast, Blake and colleagues⁴⁵ observed no apparent damage to the IMA on CUSA settings of 100%, 40% damage or trauma with conventional electrocautery, and 20% damage with CUSA settings of 60% to 80%.

With the Harmonic Scalpel, there is very little transfer of thermal energy and no transfer of electrical energy to the tissues. Coulson and Bakhshay¹⁸ demonstrated less than 1°C rise of temperature at 0.5 cm from the point of contact. Macroscopic lateral tissue damage extended to only 1 mm and microscopic tissue damage extended to only 3 mm from the point of contact. Tissue charring and desiccation was minimal. Endothelium-dependant re-laxation as a response to pharmacologic agents has been noted to be greater in radial arteries dissected with the Harmonic Scalpel.

Potential adverse effects of USAs include thermal damage, vascular perforation, and nonocclusive debris or emboli in the vessels. Vascular damage can be minimized by applying energy coaxially or parallel to the vessel and not perpendicular to the vessel wall. Local heat dissipation with saline infusion and contact pulses of shorter duration help to reduce delivered energy.

	Disadvantages of Ultrasonic Devices

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 
Ultrasonic devices are slower for coagulation compared to electrocautery. Up to 5 seconds of contact may be needed to coagulate some bleeding sites. Moreover, blade fatigue, temperature elevation, excessive applied pressure, or improper use may alter harmonic frequency or impedance of the acoustic system of USAs. Atomization of fluid may create a transient mist. However, overall dissection time may be shorter with ultrasonic cavitation aspirators or ultrasonic-activated scalpels after the initial learning curve.

	Discussion

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 
Ultrasonic aspirators are spin-offs from the ultrasonic Phaco-Emulsifier originally developed by Kelman for cataract surgery about 30 years ago.^46,47 Initially, the dental sonic-scaling instrument was modified for use in aortic valve surgery.¹ Current use of these devices in cardiovascular surgery is limited. It was documented in subepicardial dissection of the Kent bundle, IMA dissection, exposure of deep-seated coronary arteries, and aortic valve decalcification in octogenarians. Kawamura and colleagues² recommended USAs in coronary arterio-venous fistula surgery and in the arterial switch operation for transposition of the great arteries. Suma and colleagues⁵ noted that USAs definitely reduced the harvesting time of IMA grafts, gave a visibly better quality of graft, and increased the ease of the operation. Subsequently, they reported the safety and ease of harvesting radial and gastroepiploic arteries with the Harmonic Scalpel and anticipated improvement of long-term results after coronary artery bypass grafting.¹⁹ However, they did not address the possible histological changes in the graft that may be induced by inadvertent direct application of USAs on the IMA during dissection. The earlier SEM study showed intact endothelium in both ultrasonically and conventionally dissected IMA and signs of endothelial disturbances in specimens of both groups.¹⁴ Therefore, such trauma to the graft is more likely to be operator-related rather than implement-related. Similar endothelial damage associated with collection of fibrin and platelets was reported with the use of electrocautery in conventional mobilization of the IMA.⁴⁸ Morphological studies established the occurrence of serious damage (craters, denudations, protruding endothelial cells) to the endothelial lining of saphenous vein grafts after routine harvesting and handling, even with no-touch techniques.⁴⁹ In contrast, the use of USAs at 5% to 10% energy output in IMA harvesting does not produce any undue damage to the graft wall.

Deliberate direct application of the Sonocor to the IMA wall produced interesting structural changes. At 5 W energy output, occasional minimal blistering was noticed on the adventitial aspect, while at higher energy output (25 W), subendothelial blistering was observed. Such ultrastructural changes caused by ultrasonic waves in human IMA have been reported.¹⁴ These changes may be related to the basic nature of sonochemical reactions.⁵⁰ Ultrasound waves, like all sound waves, consist of cycles of compression and expansion. Compression cycles exert a positive pressure, pushing the molecules together. Expansion cycles exert a negative pressure, pulling the molecules away from one another. Small cavities are generated during expansion cycles, which enlarge and finally implode. The intensity of implosion determines the resultant changes in the immediate environs. The exact nature of the interaction and a cause-effect relationship between the tip of the ultrasonic device and the subendothelial matrix components still need further study and elucidation. As the Harmonic Scalpel operates at a higher frequency (55.5 kHz) and lower amplitude of vibration (65 to 80 microns), such damage is likely to be less.

The use of ultrasonic devices has expanded to many areas of cardiac surgery. Although the experience remains limited, the preliminary observations of the efficacy of these implements justify further use.

	References

TOP Abstract Introduction Magnetostrictive Aspirators Electrostrictive Aspirators Ultrasonic-Activated Scalpels Cardiac Surgical Applications Effects of Ultrasonic Devices Disadvantages of Ultrasonic... Discussion References

 

1. Brown AH, Davies PG. Ultrasonic decalcification of calcified cardiac valves and annuli. Br Med J 1972;3: 274–7.

2. Kawamura T, Wada J, Kasgai T. Application of CUSA system to cardiac surgery: division of Kent bundle in WPW syndrome. Rinsho Kyuobu Geka 1983;3:513–5.

3. Mitsui T, Onizuka M, Ijima H, Maeta H, Okamura K, Sakai A, et al. Ultrasonic aspiration in coronary artery surgery. Ann Thorac Surg 1985;40:199–200.[Abstract]

4. Bredikis J, Mukauskas F, Zebrauskas R, Sakalauskas J, Loschilov V, Nevsky V, et al. Cryosurgical ablation of right parietal and septal accessory, atrioventricular connections without the use of extracorporeal circulation. J Thorac Cardiovasc Surg 1985;90:206–11.[Abstract]

5. Suma H, Fukumoto H, Takeuchi A. Application of ultrasonic aspirator for dissection of the internal mammary artery in coronary artery bypass grafting. Ann Thorac Surg 1987;43:676–7.[Abstract]

6. Nakanishi N, Takada K, Ueda M, Hasegawa T, Kazui T, Komatsu S. A case of myocardial bridging successfully treated by supra-arterial myotomy using CUSA (Cavitron ultrasonic surgical aspirator). Kyobu Geka 1987;40:1029–32.[Medline]

7. Eguaras MG, Saceda JL, Luque I, Concha M. Mitral and aortic valve decalcification by ultrasonic energy. Experimental report. J Thorac Cardiovasc Surg 1988; 95:1038–40.[Abstract]

8. Sternleib JJ, Basha JW. Ultrasonic restoration of severely calcified aortic valve. Lancet 1988;11:466.

9. Mindich BP, Guarino T, Krenz H, Li X, Gonzales E. Aortic valve salvage utilizing high frequency vibratory debridement (abstract). J Am Coll Cardiol 1988; 11(Suppl):3A.

10. Worley SJ, King M, Edwards WD, Holmes DR Jr. Electrohydraulic shock wave decalcification of stenotic aortic valves: postmortem and intraoperative studies. J Am Coll Cardiol 1988;12:458–62.[Abstract]

11. Watanbe S, Koyanagi H, Endo M, Yagi Y, Shiikawa A, Kasanuki H. Cryosurgical ablation of accessory atrioventricular pathways without cardiopulmonary bypass: an epicardial approach for Wolff-Parkinson-White syndrome. Ann Thorac Surg 1989;47:257–64.[Abstract]

12. Johnson RG, Thurer RL, Lorell BH, Weintraub RM. Ultrasonic debridement of calcified pericardium in constrictive pericarditis. Ann Thorac Surg 1989;48:855–6.[Abstract]

13. Schistek R, Ghosh P, Muss W, Lametschwandtner A, Unger F. Ultrasonic preparation of the internal thoracic artery. Thorac Cardiovasc Surgeon 1990;38(Suppl):110.

14. Muss W, Lametschwandtner A, Schistek R, Ghosh PK, Thurner J, Unger F. Partiell Endothel-Denudation in der Arteria Thoracica interna (ATI) nach preparation mit einem Ultraschall-Aspirator. Lichtmikroscopische, Raster und transmissionelektronenmikroscopische Befunde. Anat Anz Zena 1991;172:58.

15. Paredes J, Borges M, Coulson A. Early impressions of the Harmonic Scalpel. Anaesthesiology 1996;8:947.

16. Ohtsuka T, Wolf RK, Hiratzka LF, Wurnig P, Flege JB. Thoracoscopic internal mammary artery harvest for MICABG using the Harmonic Scalpel. Ann Thorac Surg 1997;63:S107–9.

17. Wolf RK, Ohtsuka T, Flege JB. Early results of internal mammary artery harvest using an ultrasonic scalpel. Eur J Cardio-thorac Surg 1998;14(Suppl I):54–7.[Abstract/Free Full Text]

18. Coulson A, Bakhshay S. The use of Harmonic Scalpel in minimally invasive coronary artery bypass surgery. Surgical Rounds 1997;20:52–6.

19. Isomura T, Suma H, Sato T, Horii T. Use of the Harmonic Scalpel for harvesting arterial conduits in coronary artery bypass. Eur J Cardio-thorac Surg 1998;14:101–3.[Abstract/Free Full Text]

20. Endoh M, Ohtsuka T, Kotsuka Y, Takamoto S. Video-assisted MICABG with right mammary carcinoma — a case report. Jpn J Thorac Cardiovasc Surg 1998;46:575–8.[Medline]

21. Tanemoto K, Kanaoka Y, Murakami T, Kuorki K. Harmonic Scalpel in coronary artery bypass surgery. J Cardiovasc Surg 1998;39:493–5.[Medline]

22. Posacioglu H, Atay Y, Cetindag B, Sariblbl O, Bket S, Hamulu A. Easy harvesting of radial artery with ultrasonically activated scalpel. Ann Thorac Surg 1998;65:984–5.[Abstract/Free Full Text]

23. Royse AG. Radial artery harvest using the Harmonic Scalpel. Ann Thorac Surg 1999;67:894–5.[Free Full Text]

24. Sisto DA, Vijay V, Karmakar M, Frymus MM. Use of UltraCision Harmonic Scalpel for isolation of intramyocardial coronary vessels during coronary revascularization of the beating heart. J Thoarc Cardiovasc Surg 1998;116:668–9.[Free Full Text]

25. Scott WJ, Neumann AL, Karp RB. Ultrasonic debridement of the aortic valve with six-month echocardiographic follow-up. Am J Cardiol 1989;64:1206–9.[Medline]

26. Freeman WK, Schaff HV, Orszulak TA, Tajik AJ. Ultrasound aortic valve decalcification: serial Doppler echocardiographic follow-up. J Am Coll Cardiol 1990;16:623–30.[Abstract]

27. Craver JM. Aortic valve debridement by ultrasonic surgical aspirator: a word of caution. Ann Thorac Surg 1990;49:746–53.[Abstract]

28. McBride LR, Naunheim KS, Fiore AC. Aortic valve decalcification. J Thorac Cardiovasc Surg 1990;100:36–43.[Abstract]

29. Cosgrove DM, Ratliff NB, Schaff HV, Edwards WD. Aortic valve decalcification: history repeated with a new result [editorial]. Ann Thorac Surg 1990;49:689–90.[Medline]

30. Schwinger ME, Colvin S, Harty S, Feiner H, Opitz L, Kronzon I. Clinical evaluation of high-frequency (ultrasonic) mechanical debridement in the surgical treatment of calcific aortic stenosis. Am Heart J 1990;120:1320–5.[Medline]

31. Sheppard BB, Milliken JC, Nelson RJ, Follette DM, Robertson JM. Ultrasonic decalcification of the aortic annulus during aortic valve replacement. Ann Thorac Surg 1991;52:59–65.[Abstract]

32. Leithe ME, Harrison JK, Davidson CJ, Rankin JS, Pierce C, Kisslo KB, et al. Surgical aortic valvuloplasty using Cavitron ultrasonic surgical aspirator: an invasive hemodynamic follow-up study. Cathet Cardiovasc Diagn 1991;24:16–21.[Medline]

33. Baeza OR, Majid NK, Conroy DP, Donahoo JS. Combined conventional mechanical and ultrasonic debridement for aortic valvular stenosis. Ann Thorac Surg 1992;54:62–7.[Abstract]

34. Kellner HJ, Pracki P, Hildebrandt A, Binner C, Eisele G, Struck E. Aortic valve debridement by ultrasonic surgical aspirator in degenerative aortic valve stenosis: follow-up with Doppler echocardiography. Eur J Cardio-thorac Surg 1996;10:498–504.[Abstract]

35. Johnson RG. Ultrasonic debridement during mitral valve reconstruction for calcified mitral stenosis. Ann Thorac Surg 1990;50:923–6.[Abstract]

36. Vander Salm TJ. Mitral annular calcification: a new technique for valve replacement. Ann Thorac Surg 1989;48:437–9.[Abstract]

37. Amano J, Fujiwara H, Sugano T, Suzuki A. Modified preservation of all annular-papillary continuity in replacement of the calcified mitral valve. Thorac Cardiovasc Surgeon 1992;40:79–81.[Medline]

38. Unnal M, Sanisoglu I, Konuralp C, Akay H, Orhan G, Aydogan H, et al. Ultrasonic decalcification of calcified valve and annulus during heart valve replacement. Texas Heart Inst J 1996;23:85–7.[Medline]

39. Baumgartner F, Pearsall P, Omari Y, Robertson J. Aortic and mitral annular remodeling using ultrasonic decalcification. Herz 1996;21:179–82.[Medline]

40. Baumgartner FJ, Pandya A, Omari BO, Pandya A, Turner C, Milliken JC, et al. Ultrasonic debridement of mitral calcification. J Card Surg 1997;12:240–2.[Medline]

41. Ninan M, Treasure T. Pericardiectomy using an ultrasonic dissector. Ann Thorac Surg 1994;58:233–5.[Abstract]

42. du Roy de Chaumaray T, Menasché P. Ultrasonic dissection: a useful adjunct to operation for calcified constrictive pericarditis. Ann Thorac Surg 1995;59:1243–4.[Abstract/Free Full Text]

43. Reyes AT, Kantrowitz AB, Issenberg HJ, Factor SM, Frame R, Brodman RF. Use of neurosurgical techniques for removal of a cardiac tumor. Ann Thorac Surg 1994;57: 741–3.[Abstract]

44. Terada Y, Mitsui T, Yazawa T. Histologic evaluation of coronary exposure using an ultrasonic surgical aspirator. Ann Thorac Surg 1994;57:1054–5.[Medline]

45. Blake KL, Watt PAC, Smith JMT, De Souza AC, Spyt TJ, Thurston H. Randomized comparison of ultrasonic aspiration versus conventional electrocautery for dissection of the human internal thoracic artery. J Thorac Cardiovasc Surg 1996;111:1194–9.[Abstract/Free Full Text]

46. Kelman CD. Phaco-emulsification and aspiration: a progress report. Am J Ophthalmol 1969;67:464–77.[Medline]

47. Kelman CD. Phaco-emulsification and aspiration: a report of 500 consecutive cases. Am J Ophthalmol 1973;75: 764–8.[Medline]

48. Lehtola AM, Verkkala K, Jarvinen A. Is electrocautery safe for internal mammary artery mobilisation? A study using scanning electron microscopy. Thorac Cardiovasc Surgeon 1989;37:55–7.[Medline]

49. Svendsen E, Dalen H, Moland J, Engedal H. A quantitative study of endothelial cell injury in aorto-coronary vein grafts. J Cardiovasc Surg 1986;27:65–71.[Medline]

50. Swalick KS. The chemical effects of ultrasound. Sci Am 1989;260:62–8.[Medline]

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Probal Ghosh Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ghosh, P. Search for Related Content PubMed Articles by Ghosh, P.