Veterinary Oral Radiowave Radiosurgery (RWRS)
REFERENCES | GLOSSARY
Oral Radiowave Radiosurgery (RWRS) in the New Millennium evolved from electrocautery instruments developed in the veterinary field over forty years ago. Radiosurgery today uses high frequency radio signals to perform fine atraumatic characteristic incisions in the oral cavity. The main advantage over other cutting modalities centers around a pressureless cut with minimal bleeding that is safe, fast, and efficient. Radiosurgery permits planing of soft tissue, eliminates scar tissue formation, and minimizes post-operative discomfort. The electrodes are self-sterilizing. Radiosurgery prevents seeding of bacteria into the incision site.
Introduction and History
William Cameron in 1928 developed one of the first electrosurgical units. His efforts led to the establishment of the Cameron Company which evolved into the Cameron-Miller Surgical instrument Company. Around the same time, William Coles, a surgical equipment development engineer, introduced an electrosurgical unit composed of two mercury diode tubes which acted as rectifiers producing a full wave modulated signal form. This came to be known as the "fully-rectified" waveform.
Dr. Maurice Oringer, the "father of dental electrosurgery," was influential in early critical research in this field. His landmark textbook, Electrosurgery in Dentistry, led to the development of electrosurgery in human dentistry. He founded The American Academy of Dental Electrosurgery in 1963.
Ten years later, in 1973, Dr. Irving A. Ellman, a human dentist and clinical electronic engineer, took electrosurgery to a new level. He developed a radiosurgery unit with ultra-high frequency and four different waveforms. From the research of Dr. Ellman, the "pure" filtered waveform originated. This development changed the face of electrosurgery. Procedures are being performed today with radiosurgery that could never have been anticipated because of this research and development. [Sherman JA]
Principles and Waveforms of Radiosurgery
Modern radiosurgery utilizes high frequency radiowaves of 3.8 to 4.0 MHz that pass between an active electrode and a metallic antenna plate which acts as the passive electrode. The tissue is interposed between these two electrodes as the radio signal travels from the active to the passive plate. Four MHz appears to be the ideal frequency. Frequencies higher than that can create channeling with damage to the tissue distal to the incision. Also, higher frequencies increase the risk of sparking with excessive lateral heat transfer [Altman RB].
The passage of high frequency radiowaves through the tissue causes these tissues to heat with cell destruction or volatilization. As the active electrode passes though this cellular altered area, an incision is created.
The radiowaves activate the water molecules within the cells that are in close contact with the active electrode and then cuts by creating a plasma layer in front of the electrode. The waves are redirected by the passive electrode [i.e. antenna] back to the energy source. The lateral heat is minimal and the tissue does not appear to be burnt either on visual inspection or histologically, [Hultcrantz E]. A study in people in which oviducts were incised with lasers (Carbon Dioxide, Nd:YAG, and KTP-532), electrocautery, and radiofrequency showed that radio frequency produced the least damage to surrounding tissue and carbon dioxide lasers produced the second lowest amount of damage when compared with scalpel incisions, [Olivar AC].
The radiosurgery signal is variable. A fully rectified waveform cuts with a combined hemostatic effect. The fully rectified-fully filtered waveform produces less hemostasis with the least lateral heat and very minimal tissue damage. In human facial plastic surgery, it is well documented that high-frequency (3.8 to 4.0 MHz) radiosurgery yields less scarring and fewer complications that laser excision, [Wedman J]. This cutting current (fully filtered and rectified) also contains a small amount of hemostatic ability (10%). It is the waveform that allows the cleanest incision with the least amount of tissue char, [Bosniak S]. In veterinary oral surgery it has a significant advantage when incising soft tissue in proximity to bone or dental tissue.
The blended current or cut-coagulation mode is fully rectified [50% cutting and 50% coagulation]. It produces more lateral heat but also has excellent hemostatic properties. It is superior in surgical resection zones that have a significant vascular bed. In humans, in radiosurgically assisted transplantation of labial salivary glands to the conjunctiva to reduce the symptoms of severe dry eye, this small coagulation effect limits the bleeding of the highly vascular mucosa, [Raus P]. Bone and dental tissue must be avoided when using this waveform. It is excellent in subcutaneous, muscle or fat dissections, [Bosniak S]. In a recent study evaluating a histologic comparison of canine skin biopsies collected using monopolar electrosurgery, CO2 laser, radiowave radiosurgery (RWRS), skin biopsy punch, and scalpel it was concluded that RWRS in the cut-coagulation mode caused less lateral thermal damage to canine skin biopsies than monopolar electrosurgery and C02 laser and less lateral thermal injury to peripheral skin than monopolar electrosurgery, [Silverman EB]. The interesting part of this study is that the researchers got these excellent results using the blended waveform. If the fully rectified-fully filtered waveform was initiated in the study, the lateral thermal injury would have been even less with the utilization of RWRS.
The partially rectified-hemostatic waveform is mainly used for coagulation of soft tissue. It produces more lateral heat but has significant hemostatic ability. This is the waveform of choice for hemostasis in vascular cutting beds away from dental or bone tissue.
The fulgurating or spark gap waveform is a radiosignal used to produce superficial destruction of soft tissue. This is not a common waveform in veterinary oral surgery but can be utilized in the destruction of cyst remnants. The spark jumps from the electrode to the tissue causing coagulation with carbonization. It produces the greatest amount of lateral heat but can be used near bone because the electrode never touches the tissue.
Bipolar forceps are available in veterinary oral radiosurgery for very precise pinpoint coagulation. The radiowave travels between the ends of the forceps and is excellent in microsurgery of difficult to reach areas, especially, in the oropharynx. In humans, in Bipolar Radiofrequency Dissection Tonsillectomy (BRDT), the use of radiofrequency waves in the bipolar mode provides a pin-point coagulation with minimal lateral heat, thus reducing the depth of the lateral thermal injury and, hence, decreasing scarring and pain, [Ragab SM].
Key Points of Understanding in Radiosurgery
There are key points to understand to reach a successful conclusion when employing radiosurgery into any surgical procedure. The slower the passage of the electrode through the tissue the greater the heat produced.
The active electrode should pass through the tissue without deliberation in a pressureless incision. If the intensity of power is set too high, there will be increased heat and sparking. If the intensity of power is too low, there will be dragging of the active electrode with increased lateral heat and increased tissue bleeding. Drag from an improperly powered electrode tends to increase hemorrhage because tissue is torn rather than cut, [Miller WW]. The operator must understand that the larger the electrode or surface area of the electrode the greater the power that is needed to complete a procedure. For example, a large loop electrode with increased surface area will require greater power and will produce more lateral heat. The Vari-Tip thin pointed tip is utilized with less power and therefore less lateral heat is produced. A high frequency 4.0MHz radiosurgery unit creates significantly less lateral heat and tissue damage than low frequency units. The active electrode cutting surface is self-sterilizing in use. The tissue being cut will also be sterilized when the electrode is applied. This prevents cross infection. [Brown JS]
Safety in Radiosurgery
It is up to the operator to investigate all electrosurgery equipment in their operatory before utilizing that equipment for the procedures discussed in this radiosurgery review. As stated, for patient safety and operator efficiency a frequency of 3.8 to 4.0 MHz is recommended. [Sherman JA] As frequency increases, to a certain optimum level of 4.0 MHz, tissue destruction decreases. The high frequency-low temperature [Ellman International Inc., Surgitron Dual RF] radio-surgical unit results in rapid and uncomplicated healing [Bouzouaya C]. To show the margin of safety, the Ellman 4.0MHz radiowave system is frequently used in neuro and spinal surgery and was used to separate Siamese twin infants in 2004 at Montefiore Hospital in New York City, [Niamtu J].
New equipment should be scrutinized for the ADA (American Dental Association) seal of acceptance. Underwriters Laboratories (UL) and the Canadian Standards Association (CSA) are other agencies that evaluate electrical equipment. Although there is no current mandatory regulation of electrosurgery equipment in human or veterinary dentistry, it behooves the purchaser to contact these agencies for units that have been tested and approved for oral or general surgical usage.
Electrode Selection and Procedures
There are a variety of electrode tips used for the different oral applications in veterinary oral surgery and for coagulation. [Ellman International, Inc.] Selection of active electrode type is based on the radiosurgery technique being performed. Common applications of radiosurgery in veterinary general practice are the gingivoplasty, gingivectomy, the full thickness mucoperiosteal flap, and tissue biopsy.
The active electrodes to be discussed are the Vari-Tip #118, Loop Electrode #128, U-Shaped Loop #108, and Pencil-point Electrode #113 F, #117.
All treatments below assume that a pre-anesthetic testing protocol has been completed and that the patient is being treated under gas inhalation anesthesia with monitoring by a nurse anesthetist. Additional administration of a block or local anesthetic to the area is always recommended for post surgical patient comfort. Complete nerve block anesthesia, splash-block anesthesia, periodontal ligament anesthesia, and direct infiltration anesthesia are all options based on the procedure being implemented. After radiosurgery, a tissue protectant, such as tincture of myrrh and Benzoin, is applied in three to four treatments with air drying between layers.
The gingivoplasty is one of the most common oral procedures performed in veterinary dentistry. This surgical procedure recontours or reshapes abnormal gingiva to return this tissue to a normal state. This correction of tissue morphology reduces plaque and calculus retention and creates a normal physiologic gingival contour [Rateitschak E]. All veterinary surgeons must familiarize themselves with this procedure. Dual frequency 4.0 MHz radiosurgery is the preference over cold steel and lasers because of decreased lateral heat production, control of bleeding, and the ability to work in juxtaposition to bone without necrosis being a problem.
The gingivectomy reduces sulcar depth and is, mainly, utilized to treat pseudopockets-suprabony pockets in cases of gingival hyperplasia. Pseudopockets are not true periodontal pockets because there is no apical profliferation of junctional epithelium or loss of connective tissue attachment, [Rateitschak E]. These pockets can be caused by medicaments, advanced periodontal disease, or other medical problems in the patient. Gingivoplasty should only be utilized in advanced suprabony pockets. Suprabony pockets can also be caused by fibrosis, benign tumors, papillomas, and gingival cysts, [Rateitschak E]. Radiosurgery correction is only initiated after a complete oral exam, probing with measurement, and oral radiographs have been taken establishing a need for the treatment.
It is very important not to bridge the attached gingiva when performing gingivectomy or gingivoplasty. The radiosurgery incision should always be at a forty-five degree angle toward the base of the pocket. The area surgically treated should be completely root planed. A periodontal dressing is essential to patient care.
To perform an oral biopsy with radiosurgery a complete understanding of oral anatomy is essential. Informed consent is imperative with any oral procedure and especially in biopsy procedures. Examination of the tissue biopsied should be performed by an oral histopathologist. Biopsies should be deep, complete, and reflect the entire tissue being examined. The pathologist should be notified to exact location, tissue type, and whether an incisional or excisional biopsy has been performed. With large mass excisional biopsy procedures, an oral surgeon and oncologist should be contacted for special imagining procedures prior to surgery and to maintain the proper margins. Many of these patients require advanced flap surgery with bone augmentation. Radiosurgery in general practice is excellent for biopsy of the tonsillar area, soft palate, gingival-mucosal sites, and the lingual-sublingual areas.
Simple Full Thickness Mucoperiosteal Flap
One of the most important procedures that a veterinarian must master is the creation of full thickness mucoperiosteal flaps. They are critical in all exodontal procedures in the pedodontic, adult, or geriatric patient [refer to photo essay ]. The simple U-flap can be created with cold steel (scalpel-Blade 15/11) but the surgical field becomes almost immediately obliterated by weeping hemorrhage that obscures the field and becomes a source of bacterial contamination. Not only does the surgeon benefit from a less difficult surgery, the patient heals more quickly and with less discomfort because of less bleeding and injury to the surrounding tissues, [Older, JJ]. High frequency- low temperature radiosurgery can create these flaps with a pressureless incision in a bloodless field. The fully rectified-fully filtered waveform is recommended. The absence of high temperature levels associated with a non-hemorrhaging incision and the ease with which the electrodes can be handled makes this technique particularly suitable for any area. [Guillaume B] & [Gupta PJ]
The Future of Radiosurgery in Rhinoscopy and Extraoral Surgery
Oral and soft tissue human and veterinary surgeons are now embarking into new frontiers of radiosurgery usage coupled with endoscopy. Successful endoscopic radiofrequency assisted dacryocystorhinostomy has been reported, [Javate RM]. Dacryocystorhinostomy (DCR) is a drainage procedure designed to bypass the site of nasolacrimal duct obstruction by forming a fistula between the lacrimal sac and the nasal cavity. This is only one combined endoscopic-radiowave application. Many others are being reviewed for other surgical applications outside the oral cavity.
The Dual Frequency Radiosurgery Active Electrode Inserts
The Vari-Tip #118 is excellent for making the initial cut for the gingivoplasty, gingivectomy, or biopsy procedure with a fully filtered-fully rectified waveform. This insert allows the depth of the incision to be varied by adjustment of length of the cutting filament. It is the most versatile of all of the radiosurgery inserts because of this feature.
A loop electrode tip #108 is excellent for biopsies. A tissue forceps lifts the area to be biopsied through the loop utilizing a fully filtered-rectified waveform. There is minimal to no tissue bleeding with this technique. It is up to the surgeon to decide whether a suture needs to be placed depending on the area and amount of tissue being resected. Any non-absorbable 4-0/5-0 synthetic suture is recommended. The fully rectified waveform can be utilized in areas that are not near bone. This waveform provides significant hemostasis as the tissue is excised. The electrode (i.e. inserts) can be bent to allow better access to the surgical sites.
After the initial incision with the Vari-Tip electrode the U-Shaped electrode #108 or #114 or the loop electrode #128 is excellent for the purpose of dissecting out a deep mass around or near a tooth. If in close proximity to tooth or bone, the radiosurgery unit should be set at the fully filtered-fully rectified waveform modality. The U-shaped and loop electrodes are also utilized to recontour gingiva and restore proper margins after gingivoplasty or gingivectomy.
The pencil-point electrodes #113F and or #117 in gingivoplasty, gingivectomy, and/or biopsy are used to coagulate any bleeding areas in the partially rectified waveform.
Education and Laboratory Sessions
Whether generalist or specialist, the journey in the radiosurgery techniques mentioned herein should not be initiated without supervised training in a laboratory setting. Anatomic and pathologic relationships must be understood prior to the laboratory experience. Multiple laboratory sessions not only assist in choosing the proper radiosurgery waveform but also allow the student to appreciate the "paintbrush stroke" essential to quality incisions. The student with cold steel is used to creating a pressure-incision. Radiosurgery is the opposite. It is a pressure-less incision and requires time and patience to develop the exact stroke technique. The use of low-temperature, high-frequency radiosurgery offers the advantage of controlling hemorrhage while reducing lateral heat damage to remaining tissue, [Elkins AD]. The student must remember that these advantages can only be mastered with a laboratory mentor and are the necessary requisites to any successful clinical application.
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Disclosure of Interest: The Ellman Surgitron Dual RF radio-surgical unit described herein was purchased by DH DeForge to use in his three specialty Oral Care Pain Control Centers: The Silver Sands Veterinary Center in Milford, CT; The New York Specialty Center in Farmingdale, LI, New York; and in The East End ER and Specialty Center in Riverhead, LI, New York. This unit is used in all surgical procedures at these centers.
The author has no financial interest or connection with the manufacturer.
- Altman RB: Radiosurgery: Seminars in Avian and Exotic Pet Medicine. W.B. Saunders, Philadelphia, Pa., pp. 180-3, 2000.
- Bosniak S: Radio-Surgery: A 25 Year History of Scarless Mole Removal: Operative Techniques in Oculoplastic, Orbital, and Reconstructive Surgery. Vol. 4, No.2, pp. 109-112, 2001.
- Bouzouaya C: Radiosurgery Can Effectively Remove Xanthelasma. Ocular Surgery News-Oculoplastic and Reconstructive Surgery, pp. 76-77, May 2004.
- Brown JS: Radio Surgery for Minor Operations in General Practice: Cosmetic Dermatology, pp. 33-36, July 2000.
- Elkins AD: Soft Palate Resection in Brachycephalic Dogs: Veterinary Forum. Vol. 22, Number 7, pp 43-46, July 2005.
- Ellman International Inc.-Seminar Advances in Veterinary Surgical Techniques-Ellman Educational Institute: 3333 Royal Av.-Oceanside, NY; 5-13-2006.
- Guillaume B: Implant Surgery and High Frequency Currents-Operative Indications: Dentistry Today. Vol. 22, Number 11, pp. 80-84, Nov 2003.
- Gupta, PJ: A Comparative Study Between Radiofrequency Ablation with Plication and Milligan-Morgan Hemorrhoidectomy For Grade III Hemorrhoids: Techniques in Coloproctology, Official Journal of the Italian Society of Colo-Rectal Surgery, Mediterranean Society of Coloproctology, and Israel Society of Colon and Rectal Surgery. Volume 8, Number 3, pp 163-168, Nov 2004.
- Hultcrantz E, Ericsson E: Pediatric Tonsillotomy with the Radiofrequency Technique: Less Morbidity and Pain: Laryngoscope 114, pp. 871-7, May 2004.
- Javate RM, Pamintuan FG: Endoscopic Radiofrequency-Assisted Dacryocystorhinostomy with Double Stent: A Personal Experience: Orbit. Vol 24, pp. 15-22, 2005.
- Miller WW: Using High-Fresquency Radiowave Technology in Veterinary Surgery: Veterinary Medicine. Vol September, pp. 796-802, 2004.
- Niamtu J: 4.0 MHz Radiowave Surgery in Cosmetic Facial Surgery: Australasian Journal of Cosmetic Surgery. Vol. 1; No. 1; 2005, pp. 52-59, .
- Older JJ: Simplified Approach to Ptosis Repair Uses Radiowaves to Minimize Bleeding: Cosmetic Surgery Times. p 20, October 2004.
- Olivar AC, Forouhar FA, Servanski DR: Transmission Electron Microscopy: Evaluation of Damage in Human Oviducts Caused by Different Surgical Instrucments: Annals of Clinical and Laboratory Science. Vol. 29, No. 4, pp. 281-285, 1999.
- Ragab SM, Bipolar Radiofrequency Dissection Tonsillectomy: A Prospective Randomized Trial: Otolaryngology-Head and Neck Surgery. Vol 133, pp 961-5, 2005.
- Rateitschak E: Diseases of the Periodontium; Gingivitis, Plaque-Induced; In Color Atlas of Dental Medicine 1-Periodontology: Thieme Medical Publishers, Inc. NY, 1989; p. 43.
- Rateitschak E: Gingivectomy (GV) and Gingivoplasty (GP); In Color Atlas of Dental Medicine 1-Periodontology: Thieme Medical Publishers, Inc., NY, 1989; p 288.
- Raus P, Radiosurgery Aids in Salivary Gland Transplants for Severe Dry Eye: Ocular Surgery News-Oculoplastic and Reconstructive Surgery. pp 16-18, December 2003.
- Sherman JA: Principles and Theory of Electrosurgery: In Oral Radiosurgery. UK, Taylor and Francis Group, pp 1-3, 2005.
- Sherman JA: Safety and Precautions: In Oral Radiosurgery. UK, Taylor and Francis Group, p 31, 2005.
- Silverman EB et al: Histologic Comparison of Canine Skin Biopsies Collected Using Monopolar Electrosurgery, C02 Laser, Radiowave Radiosurgery, Skin Biopsy Punch, and Scalpel: From the Departments of Clinical Sciences and Pathobiology, College of Veterinary Medicine, Mississippi State University: In Veterinary Surgery, 36: pp 50-56, 2007.
- Wedman J, Miljeteigh H: Treatment of Simple Snoring using radiowaves for ablation of uvula and soft palate. A Day-Case Surgery Procedure: Laryngoscope 112: 1256-59, 2002.
Radiowave Radiosurgery Waveforms: [All Waveforms being discussed are Radiosurgery 4.0MHz waveforms]
- Fully Rectified Filtered Waveform
- Continuous flow of high frequency energy
- Least amount of lateral heat
- Least amount of tissue shrinkage
- Allows cutting close to bone due to minimal amount of lateral heat produced
- Fully Rectified Waveform
- Full wave current modified by electronic filtration
- Produces cutting with simultaneous hemostasis
- Cauterization occurs on either side of electrode tip
- Does create tissue shrinkage
- Additional lateral heat is produced
- Should not be used in close proximity to bone
- Partially Rectified Waveform
- Intermittent flow of the high frequency current
- Excellent in producing hemostasis of soft tissue
- Produces a great amount of lateral heat and tissue shrinkage
- Not used for coagulation in close proximity to bone
- When coagulating soft tissue, the area should be freed of blood using gauze before placing the electrode on the bleeding vessel
- Radiosurgery: the introduction of a high frequency Radiowave of 4.0MHz [above AM and below FM frequencies.] The high frequency radiosignal produces a pressureless, micro-smooth incision with hemostasis and minimum tissue alteration.
Reference for Glossary 1-4
[Principles and Theory of Radiosurgery-JA Sherman-Oral Radiosurgery-An Illustrated Clinical Guide, Taylor and Francis,3rd Edition, Chap. 7, p.49, 2005.]
- Fully Rectified Mucoperiosteal Flap: a flap that is reflected beyond the mucogingival border into the region of the mobile oral mucosa in vestibular, buccal, labial, and lingual regions. Full thickness is to be differentiated from split-thickness flaps; a fully reflected mucoperiosteal flap permits a broad overview of the surgical field. The "U" Fully Rectified Mucoperiosteal flap incorporates two vertical diverging incisions and has also been called a triangular flap.
Ed Note: [This should not be confused with the Split-U-Flap for repair of Palatal Defects [Manfra-Marretta S, Grove TK, Grillo GF. Split U-Palatal Flap: A new technique for repair of a caudal hard palate defect. J Vet Dent 1991:8(1):5.]
- Gingivectomy [GV]: a periodontal procedure to eliminate gingival overgrowth or enlargement by resection of gingival tissue to create a new gingival margin; commonly used in periodontal surgery in conjunction with Gingivoplasty [GP] and in crown lengthening procedures in prosthodontics.
- Gingivoplasty [GP]: a periodontal procedure addressing gingival deformities; used to correct, reestablish, or create physiologic gingival contour.
- MGJ-Mucogingival Junction: the point at which the alveolar mucosa becomes gingiva; also called the mucogingival line-In GV or GP [excision and recontouring] the MGJ or MGL should not be touched. The GV or GP is contraindicated for the treatment of Infrabony pockets and when attached gingiva is narrow or absent.
Reference for 5-8-Glossary<
Rateitschak E: Gingivectomy (GV) and Gingivoplasty (GP); Color Atlas of Dental Medicine I-Periodontology: Thieme Medical Publishers, Inc., NY, 1989; p. 228.
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