Lajos Gáspár D.D.S., Ph.D., and Péter Vágó DDS., Ph.D.
Department of Oral and Maxillofacial Surgery, Central Military Hospital, Budapest,
Department of Stomatology, Haynal University of Health Sciences, Budapest, Hungary

Abstract

In their patient population, the authors summarise experience with 4032 laser operations of oral lesions, the manifestation of the advantages and disadvantages of this technique. The haemostatic effect of the laser is of special significance, which became evident in the surgery of vascular lesions and patients with clotting disturbance. For protection of the healthy tissues, various laser surgical methods were used-coagulation, vaporisation, excision- the postoperative oedema, pain, inflammation, wound healing disturbances, and scarring were minimal. By the use of this method, the oral cavity functions can be well maintained. Following the CO2, Nd Yag, Argon, Combi (CO2+NdYAG) laser treatment, the number of complications (oedema, pain, scar formation) was low. The laser treatment is economically favourable, since the absence of patients from work is minimal. Methods have been elaborated to overcome the disadvantages of laser treatment. The advantages of four type surgical laser treatments in oral surgery manifest themselves very markedly.

Key words: Laser surgery, oral surgery, advantages,

Address reprint requests to Lajos Gáspár, DDS, PhD, Budapest, 1029, Zsiroshegyi ut 118. Hungary.

Introduction

The laser, a recent thermotherapy tool, is used in various fields of medicine. Its application in oral surgery is becoming more and more widespread, and favourable experience has been accumulated especially in surgery of vascular lesions and precancerous conditions. The timely and successful treatment of the latter is of special significance because of the dramatically increasing incidence and the resultant mortality of oral cancers.

In the past 20 years, during which laser surgery has come into focus, various pros and cons have arisen. 1-7 Although the data are occasionally contradictory, the definite advantages of laser therapy are becoming overwhelming. Our own experience concerning the advantages and disadvantages of using the CO 2, Nd YAG, Argon, Combi (CO2+Nd YAG) lasers in oral surgery is described.

The fact that the focused CO2 laser beam is useful for cutting the tissues was revealed as early as 1966, when it was proved that in view of the homeostatic effect, an almost bloodless incision could be made on hepatic tissue. First in cadaver investigations and later in clinical practice, it was shown by Jako 17 that a region of predetermined size could be removed from the larynx with saving of the surrounding tissues (function-preservative operations).Kaplan, 18-19 experiencing minimal scarring, widely applied the CO 2 laser in plastic surgery. Oosterhuis 2o confirmed the advantages of using the laser in tumour surgery. Hall, 15 in 1971, reported that the laser-incised wound has a sharp border and healing is almost scar-free. Sowislo et al. 25 proved in their study of wounds cut by surgical knife, electrocautery and CO2 laser, the advantages of the laser:sharp wound edges, minimal blood loss, lack of oedema, and minimal scar tissue. The laser beam can be applied in a no-touch manner: thus, the instrument does not pass tumour cells to the surroundings (ablastic instrument). 13,14,16,21,22,23,24,26,

In comparison with other instruments, the relapse rate is minor following laser application, and it can be repeated several times, with a broad spectrum of indications. The number of postoperative oedema, pain, scar formation is minimal. It has become evident that the use of the surgical laser results in considerable financial savings for the health service. 8-12

The most significant disadvantages to laser application derive from the fact that it is troublesome to direct the laser beam to the target area in deep tissues, and sterile conditions must be ensured. Safety precautions must be observed, and the resulting vapour must be drawn off. The instruments are still extremely expensive. These advantages and disadvantages in oral surgery are unelucidated in numerous aspects, although they must be clarified for the routine use of the laser beam.

Materials and Methods

In our department, a Scalpel-1, Tungsram TLS 62, Sharplan 1040, CO 2 laser, Medi-YAG 100 Nd YAG laser, Combo 5050 Lasermatic CO2+Nd YAG laser were used. Between January 1, 1987 and December 31, 1993, 4032 oral lesions were removed with laser surgery (Table 1.).

There were 2219 male and 1813 female patients, with a mean age of 45.8 years (range:0.5 to 94 years).

89 of those operated on suffered from clotting disturbances ( thrombocytopenia, hypothrombinemia) and 473 were assigned to risk groups for other reasons:

cardiac and vascular disease (cardiac rhythm disorder, hypertension, coronary circulatory disorder), renal disease (renal insufficiency), hepatic disease (cirrhosis, chronic hepatitis, hepatic insufficiency) endocrine disease (diabetes insipidus, Addison s disease, diabetes mellitus)

The majority of the patients who underwent laser surgery presented for stomatologic consultation performing regional tasks as well, with dental or stomatosurgical reference. Prior to surgery, a tissue sample was taken for histological examination in cases tumours, precancerosis, unclarified situations..

The operations were performed under local anaesthesia (2% lidocaine, 0,001% adrenaline). During surgery for simple benign tumours the lesion was removed with 1 mm , in precancerous cases with 1- 5 mm , and in suspect malignancies or malignant tumours with 5- 30 mm of healthy tissue depending the nature of the oncological aspects of disease. Three types of laser operations were performed :

Coagulation

(simple leukoplakia, cheilitis, ) using a 5 W power defocused CO2 laser beam. (naevus flammeus) using 2 W power argon laser beam (cavernosus haemangioma) 20 W Nd YAG defocused laser beam Vaporisation

(verrucous leukoplakia, cheilitis, lichen, haemangioma capillare etc.) using a 10 to 15 W focused or defocused CO2 laser beam. (benign tumours of haemophilic patients) 25 W Nd YAG focused or defocused laser beam (high vascularized tumours) 15 -30 W focused combi laser beam.

Excision

(ulcerous leukoplakia, cornu cutaneum, erythroplakia , carcinomas , plastic surgery etc.) using a 20 to 25 W CO2 laser beam or 30 W Nd YAG laser beam or 15-30 W combi laser beam..

(Table 2., Table 3.)

In the first two types, the tissues are touched only by the laser beam: in the third one, the excision is made by applying continuous traction to the pathologic area. The minor vessels are coagulated by the laser beam during cutting: vessels with a diameter larger than 1 mm ( CO2) or 2- 3 mm ( Nd YAG and combi) are identified and severed between the ligatures.

Results

Surgery could be performed on a practically bloodless wound surface. In the case of vaporisation, the laser beam immediately coagulated the vessels less than 1 mm (CO2) or 2- 3 mm (NdYAG and combi) in diameter : in the case of excision, the major vessels exposed on the wound surface were recognised and cut between the ligatures when necessary. The 89 haemophilic patients were also operated on without any bleeding.

The application of the laser beam ensures ablastic operation. In our patient population, the embedding histological examination-with the clinical picture of erosive leukoplakia-verified carcinoma in situ from the laser-excised tissue in 6 cases. Since, in the preoperative histology, we diagnosed erosive leukoplakia, we did not extend the degree of the laser excision. During follow-up 2-7 years postintervention, close observation revealed neither local recurrence nor regional metastasis. Oncological evaluation of our other operations would be a futile exercise, owing to the oncopathologic character of the lesions.

During coagulation and vaporisation, the tissues were touched only by the laser beam. During excision, only the continuous traction of the pathologic area was performed using conventional instruments. Healthy tissues were not tugged or traumatized:no pathogens or their toxins or tumour cells were transmitted by this "no-touch" technique onto the healthy regions. This tissue-saving technique results also from the fact that the coagulation and vaporisation performed by the laser beam allows greater selectivity than any other existing method, removing only the pathologic tissues while sparing the healthy structures. In the case of cutting the CO2 laser knife results in a thermodamaged zone of 300 microns in thickness: thus the thermal damage of the healthy area is minimal.

The aseptic applicability results partly from the fact that the laser beam immediately destroys the pathogens on the incised surface, after lasing, the wound surfaces are covered by a protective layer of coagulated proteins, which provides favourable conditions for the epithelialization of the occasionally large areas concerned.

Following the removal of 4032 lesions inflammatory phenomena developed in 68 cases ( 1.7%) , but patients recovered with targeted antibiotic treatment.

Except for 68 inflammations, 201 suture-united wounds, and 139 other intervention, no oedema developed in the postoperative period (table 4.).

Following coagulation and vaporisation, regardless of the size and site of the lased surface, no moderate (requiring correction due to functional or aesthetic causes) or minimal (only minimal aesthetic fault) scare tissue developed in 3198 cases (79.2%).(Table 5.) Fig.1.

Regarding the degree of postoperative pain, the evaluation was based on patients , reports. Of the 4o32 patients operated on, 1o86 (26.9%) required analgesics on the day of the operation. One day later, only 291 (7.2%) patients required analgesics. On the operative day, the patients did not observe swallowing or nourishing disturbance: they were able to take oral nourishment by themselves (Table 6.).

As to the speed and quality of wound healing, the epithelialization terminated by the third week in case of coagulation, and by the fourth week when vaporisation and excision were performed. Lesions of smaller surfaces recovered sooner. The multicentric leukoplakias were removed usually in one sitting: their healing was more prolonged, varying with their extent, taking up to the fourth or fifth postoperative week. Fig.2.

When evaluating the patients after a follow-up of 2-7 years, we found that out of 4o32 patients, 3838 were symptom free (95.1%) . Recurrence developed in 184 cases and 1o patient died due to other (cardiovascular) disease. In the relapsing cases, a second lasing was performed that resulted in a symptom-free condition (in 151 of the 184 cases).

Discussion

Laser surgery ensures, besides the safe removal of the oral lesions, the considerable maintenance of oral functions. The fact that we can adhere strictly to removal of the pathologic tissues only and that the wound healing takes place with minimal scarring, assures favourable reception of the procedure from both functional (nourishment, speech, mimics) and aesthetic points of view. This goal is achieved by all three individual laser surgical interventions (coagulation, vaporisation, excision) or, occasionally, by their combined application. Thus, the radically required by the severity of the lesion can be counterbalanced by the maximal potential preservation of the healthy tissues. Favourable aesthetics and functional results were seen in cases of CO2 or argon laser coagulation and vaporisation. The cutting procedure is favourable by CO2 laser beam.

Due to its 2- 4 mm depth of effect the Nd YAG laser ensures better coagulation than the carbon dioxide one, it can also close larger vessels although larger healthy tissues get damaged. The Nd YAG laser is highly favourable in the treatment of haemophilic patients and major vascular lesions.

The combined laser (CO2+Nd YAG) application makes it possible to achieve proper coagulative and cutting effect corresponding to the properties of the structures. In more haemophilic cases wider coagulation is made mostly with Nd YAG beam and less CO2 is applied while in interventions requiring less coagulation the CO2 laser outweighs the use of Nd YAG.. By combined application the coagulation and cutting effect could be adjusted to any desirable extent.

Laser therapy represents significant savings for the national economy the purchase of the laser equipment requires a single investment, but further maintenance or material costs are unremarkable. The instrumental demand of the laser operations is minor. as a rule, not even sutures are necessary. Since the results in a high response rate after only the first treatment, the manifold travelling by patients can be avoided and their absence from work is minimal. One day after surgery, 90% of those operated on are already capable of resuming work. We consider it a remarkable advantage of lasing that the initial treatment ensures a response equal to two, three, or several cryotreatments.

Based on the experience gained so far we are of the opinion that one of the most important oral surgical indications of the laser beam are the therapy of oral precancerosis, haemangiomas, epulis and the treatment of haemophilic patients.

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