 Veterinary Oral Radiowave Radiosurgery (RWRS)
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.
Gingivoplasty-Gingivectomy-and Biopsy
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.
PHOTO ESSAY:
* * *
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.
1. Altman RB: Radiosurgery: Seminars in Avian and Exotic
Pet Medicine. W.B. Saunders, Philadelphia, Pa., pp. 180-3, 2000.
2. Bosniak S: Radio-Surgery: A 25 Year History of Scarless
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Reconstructive Surgery. Vol. 4, No.2, pp. 109-112, 2001.
3. Bouzouaya C: Radiosurgery Can Effectively Remove
Xanthelasma. Ocular Surgery News-Oculoplastic and Reconstructive Surgery,
pp. 76-77, May 2004.
4. Brown JS: Radio Surgery for Minor Operations in General
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Surgical Techniques-Ellman Educational Institute: 3333 Royal Av.-Oceanside,
NY; 5-13-2006.
7. Guillaume B: Implant Surgery and High Frequency
Currents-Operative Indications: Dentistry Today. Vol. 22, Number 11, pp.
80-84, Nov 2003.
8. Gupta, PJ: A Comparative Study Between Radiofrequency
Ablation with Plication and Milligan-Morgan Hemorrhoidectomy For
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the Italian Society of Colo-Rectal Surgery, Mediterranean Society of
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the Radiofrequency Technique: Less Morbidity and Pain: Laryngoscope 114,
pp. 871-7, May 2004.
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Radiofrequency-Assisted Dacryocystorhinostomy with Double Stent: A Personal
Experience: Orbit. Vol 24, pp. 15-22, 2005.
11. Miller WW: Using High-Fresquency Radiowave Technology in
Veterinary Surgery: Veterinary Medicine. Vol September, pp. 796-802, 2004.
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52-59,
.
13. Older JJ: Simplified Approach to Ptosis Repair Uses
Radiowaves to Minimize Bleeding: Cosmetic Surgery Times. p 20, October
2004.
14. Olivar AC, Forouhar FA, Servanski DR: Transmission Electron
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15. Ragab SM, Bipolar Radiofrequency Dissection
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16. 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.
17. Rateitschak E: Gingivectomy (GV) and Gingivoplasty (GP);
In Color Atlas of Dental Medicine 1-Periodontology: Thieme Medical
Publishers, Inc., NY, 1989; p 288.
18. Raus P, Radiosurgery Aids in Salivary Gland Transplants
for Severe Dry Eye: Ocular Surgery News-Oculoplastic and Reconstructive
Surgery. pp 16-18, December 2003.
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GLOSSARY:
Radiowave Radiosurgery Waveforms: [All Waveforms being discussed are
Radiosurgery 4.0MHz waveforms]
1. Fully Rectified Filtered
Waveform
o
Continuous
flow of high frequency energy
o
Least
amount of lateral heat
o
Least
amount of tissue shrinkage
o
Allows
cutting close to bone due to minimal amount of lateral heat produced
2. Fully Rectified Waveform
o
Full wave
current modified by electronic filtration
o
Produces
cutting with simultaneous hemostasis
o
Cauterization
occurs on either side of electrode tip
o
Does
create tissue shrinkage
o
Additional
lateral heat is produced
o
Should
not be used in close proximity to bone
3. Partially Rectified Waveform
o
Intermittent
flow of the high frequency current
o
Excellent
in producing hemostasis of soft tissue
o
Produces
a great amount of lateral heat and tissue shrinkage
o
Not used
for coagulation in close proximity to bone
o
When coagulating
soft tissue, the area should be freed of blood using gauze before placing
the electrode on the bleeding vessel
4. 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.]
5. 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.]
6. 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.
7. Gingivoplasty [GP]: a periodontal procedure addressing
gingival deformities; used to correct, reestablish, or create physiologic
gingival contour.
8. 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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