CO2 and Nd:YAG laser systems in microsurgical venous anastomoses

Summary A comparative study was undertaken in 81 rats to investigate a CO₂ and Nd:YAG laser system for laserwelded anastomosis of the femoral vein. Conventionally sutured anastomoses (CMSA) served as controls. Laserwelded anastomosis (LAMA) was easier and could be performed 30% faster than CMSA. Postoperative investigations included patency tests, postmortem examinations and light and electron microscopy. Aneurysms were not seen. Foreign-body reaction was more pronounced in CMSA. Patency rates for CO₂-LAMA and CMSA were equal, whereas Nd:YAG-LAMA resulted in significantly higher rate of early postoperative thrombosis (P<0.01). Because of its physical properties, the CO₂-laser system seems to be better suited for laser welding of delicate structures such as the rat femoral vein.     

Treatment of Small Congenital Nevocellular Naevi Using a Combination of Ultrapulse Carbon Dioxide Laser and Q-Switched Frequency-Doubled Nd-YAG Laser

This report describes treatment combining Ultrapulse CO₂ laser and Q-switched frequency-doubled neodymium:yttrium-aluminum-garnet (Nd-YAG) laser for a number of congenital nevocellular naevi (CNN). The Ultrapulse CO₂ laser removes the superficial component, which contains most of the color, preserving the integrity of the reticular dermis. At a later stage, any residual color is targeted using the Nd-YAG laser. To date, a total of 10 histologically proven CNNs have been treated at the Laser Suite. The median age of the patients was 18 years (range, 13–24 years). All the patients were white females. The patients accepted for treatment had relatively small lesions (mean surface area, 352 mm²; range, 50–1,092 mm²), but the lesions were either cosmetically sensitive or located in an anatomically critical area in which excision could result in a scar that would be unpredictable. The median follow-up period was 24 months. The overall results have been satisfactory, with reduction of color and no significant scarring. The minor textural and pigmentary changes were acceptable to the patients.     

The treatment of vascular malformation of the brain with laser source

The first three cases of vascular malformations in humans (two artero-venous aneurysms and one saccular aneyrysm) treated with the association of CO₂ laser and Neodymium: Yag lasers, are presented here. The post-operative course has been very good. However, it is still necessary to examine a larger number of cases to see if, how, and when this treatment can be utalized in place of traditional methods.     

An alternative method of vascular anastomosis by laser: experimental and clinical study

In vascular surgery, it is now very difficult to maintain the long-term patency after a conventional vascular anastomosis, especially for small-caliber vessels. A low-energy CO2 laser was experimentally employed to make a vascular anastomosis with only a few sutures. Subsequently, it could be confirmed that optimal conditions for vascular anastomosis by laser were 20-40 mW in output and 6-12 sec/mm in irradiation time. On the other hand, pressure tolerance test as well as tensile strength test and microscopic examinations at the sites of anastomoses by laser were compared with the conventional suture method. There were no significant differences between laser and suture methods. On the basis of the excellent results of this study, the laser was clinically applied for anastomoses of the peripheral vessels in 35 patients. The first clinical laser application in the world was successful in a 44-year-old female patient with chronic renal failure in 1985. All patients are doing well without any complications from vascular anastomosis by laser. From these experimental and clinical studies, it can be concluded that anastomosis by laser should be recommended for small-caliber vessels such as aortocoronary bypass surgery.     

Multiple adjustable vascular clamp prototype: Feasibility study on an experimental model of end-to-side microsurgical vascular anastomosis

The aim of this study was to establish the feasibility of microsurgical end-to-side vascular anastomosis with a multiclamp adjustable vascular clamp prototype in an inert experimental model. Our method consisted of performing an end-to-side microsurgical anastomosis with 10/0 suture on a 2-mm diameter segment. In group 1, the end-to-side segment was held in place by a double clamp and a single end clamp. In group 2, the segment was held in place with a single multiclamp adjustable clamp. The average time for performing the anastomosis was shorter in group 2. The average number of sutures was the same in both groups. No leak was found and permeability was always positive in both groups. Our results show that performing end-to-side anastomosis with a multiclamp adjustable vascular clamp is feasible in an inert experimental model. Feasibility in a live animal model has to be demonstrated before clinical use.     

Effects of low-power laser irradiation on survival of random skin flap in rats

This research was designed to study the effects of low-power helium–neon (He–Ne) laser irradiation on random skin flap survival in rat. Fifty 50 male rats were randomly divided into five groups. On the dorsum of each rat, one full thickness random skin flap which contained no specific vessel was elevated. Groups 1 to 4 were exposed to different models of a low-power He–Ne laser. Group 5 rats received no laser treatment and were considered as the control group. The energy density of the He–Ne laser used was 0.2 J/cm². Immediately after surgery and at day 7, the surface area of all flaps was determined. Histological and tensiometrical studies on the surviving part of the flaps were also performed. The data obtained were analyzed by ANOVA. The results showed a significant difference in the surface area of survival parts of flaps and density of blood vessels on day 7 between group 3 rats and the other groups (P=0.0188, P=0.0455). Low-power He–Ne laser irradiation of flaps without recognized blood vessels in rats, reduced vasospasm, produced vasodilation, and caused a significant increase in the surviving surface area.Presented at the 14th World Congress of the International Society for Laser Surgery and Medicine, India, 27–30th August, 2001     

Carbon Dioxide Laser Resurfacing with Fast Recovery

Abtract Long sun exposure, in addition to ozone layer damage, produces structural damase to the normal skin. Injury to the dermal collagen and elastic fiber results in facial wrinkles. Photodamage to the skin is one of the most common sources of concern for patients visiting the plastic surgeon or dermatologist. Over the years, many alternative solutions have been developed. CO₂ laser treatment is one of the alternatives bringing unique benefits and satisfactory results for both patient and surgeons. However, the initial problems of emotional discomfort, prolonged postoperative recovery and delayed return to normal activities have made patients reluctant to accept this method. This article discusses single-pass CO₂ laser resurfacing with lower energy. Also, it proposes a technique that does not use wet gauze to remove the surface of the skin. This technique is applied in combination with an intensive skin care treatment. Different authors propose a single pass of CO₂ laser with excellent results. With the reported method, identical long-lasting benefits are achieved, but the post-operative time is shorter.     

Uvulopalatopharyngoplasty with CO2, contact ND-YAG or combined CO2 and ND-YAG laser beams

Three different surgical lasers, ie CO₂, contact Nd-YAG and Combolaser (combined simultaneous and co-axial CO₂+Nd-YAG laser beam), were used for 76 uvulopalatopharyngoplasty (UPPP) operations. The effects of different lasers on intra-operative bleeding, operation time and post-operative pain were compared. Sixty patients with obstructive sleep apnoea syndrome (OSAS) and 16 patients with socially disturbing snoring were operated on. The CO₂ laser was used in 24 patients, contact Nd-YAG was used in 27 patients and Combolaser was used in 25 patients. The Combolaser was associated with significantly less intra-operative bleeding and a shorter operation time. During the immediate recovery period, post-operative pain was most mild after operations with the CO₂ laser when graded according to need for analgesics, or by the patients' subjective evaluation. Concerning possible post-operative complaints or overall outcome of the UPPP operation, no differences were found between the lasers.     

Longterm comparison of soft palate scars after UPPP made by CO2, contact Nd-YAG or combined CO2 and Nd-YAG laser beams

C0₂ laser, contact Nd-YAG laser and Combolaser (combined CO₂ and Nd-YAG laser beam) vary distinctively in the way they interact with target tissue. To study the quality of mature scars produced by these lasers, the ultrastructure and amount of collagen in soft palate scars after 60 uvulopalatopharyngoplasty (UPPP) operations were analysed. The CO₂ laser was used in 19, contact Nd-YAG in 21 and Combolaser in 20 operations. At a clinical follow-up examination carried out, on average, 51 (range 34–74) months postoperatively, a specimen was obtained from the soft palate scar for collagen analysis. Postoperative complaints of the patients were acknowledged. No differences between the laser groups were observed concerning the gross appearance of the scars or the amount and ultrastructure of collagen. Neither the frequency nor the quality of post-operative symptoms showed any differences between the lasers. Although the initial tissue effects are different, long-term remodelling produces nearly identical soft palate scars after the use of CO₂, contact Nd-YAG and Combolaser beams.     

Skin-edge necrosis in irradiated tissue after carbon dioxide laser excision of tumour

We report a case in which a super-pulsed carbon dioxide (CO₂) laser was used to excise recurrent tumour in a previously irradiated field. After reconstruction with free tissue transfer there was necrosis of the excision margins. The poor healing of the skin edges is discussed with regard to aetiology and prevention. The importance of laser spot-size, irradiance and fluence in describing surgical technique is emphasized.     

Assisted aortic valve decalcification with the CO2 laser: Study of 15 valves in vitro

Calcification of heart valves is one of the most important reasons for valve replacement surgery (1). Currently available heart valve replacements are not perfect (2–6). Therefore it is desirable to retain the native valve. Many methods, such as manual decalcification, ultrasound (7,8) and balloon valvuloplasty (9) have been tried. Recent studies have suggested the use of lasers (11–13). We decalcified 15 aortic valves removed at surgery in vitro using the CO₂ laser and conclude that this method would be feasible in valves with very minor calcification but inappropriate when the calcification is extensive.     

The use of the Nd-YAG and the CO2 laser in neurosurgery

Summary Over the last 3 years 120 patients have been operated on using laser techniques. This technique was chosen where technical difficulties were anticipated due to the size, the vascular supply or the localization of the process. Although the use of laser technique requires experimental work, before it can be applied clinically some distinct advantages could be demonstrated when compared with the use of the bipolar cautery.Due to its shrinking effect the laser beam is target oriented and makes the surgical procedure safe without the use of additional instruments. The Nd-YAG laser was preferred in tumors with a rich vascular supply. Thus there was a definitely decreased need for blood transfusions in patients operated on with the laser. Even those parts of the tumors that can not easily be reached, using conventional techniques can now be eliminated by laser irradiation.The variable distance between the handpiece of the laser instrument and the target organ allows a pin point as well as a more diffuse irradiation. Since it is not necessary to touch the tissue, laser techniques are particularly useful in critical areas, e. g. close to the brainstem or the spinal cord, because they make it unnecessary to touch the tissue.The question as to whether the use of laser technique will reduce the rate of recurrent tumor growth needs further studies based on longer follow-up periods. Further technical improvements are needed to make the laser device a true microinstrument. Finally a combination of both laser types — that is the Nd-YAG laser for coagulation and the CO₂ laser for cutting -might be a definite advantage.Dedicated to Prof. Dr. Dr. h. c. K. J. Zülch on occasion of his 70th birthday.     

Surgical treatment of erythroleukoplakia in lower lip with carbon dioxide laser radiation

Erythroplakia is considered to represent a premalignant condition and is felt to be at high risk to progress to oral cancer development. When the lesion presents with red and white mucosal alterations concomitantly, the term erythroleukoplakia is used. However, in erythroleukoplakia lesions, the red or erythroplakia areas have been shown to be most likely to demonstrate dysplastic changes compared to the white hyperkeratotic areas. We present a case of patient with erythroleukoplakia involving the lower lip that was treating with carbon dioxide laser radiation (CO₂) with 0.8 mm focus, 5 W, power density of 2.5 W/cm² in continuous. After the surgery, the vaporized surface was protected with a fibrinolisine + chloramphenicol cream. To date, after 6 months, there has been no clinically evident recurrence on the vermilion area. The functional and esthetic results observed were judged to be excellent.     

Carbon dioxide laser management of ventricular dysphonia

Resection of the ventricular folds of the larynx was done, with the aid of a carbon dioxide laser, on seven patients who had either an essential or a symptomatic ventricular dysphonia. The initial results were very encouraging, but the ventricular dysphonia recurred in two patients. A problematic case history is summarized, exemplifying difficulties in choosing the right patients for surgery.     

Humility

Laparoscopic techniques are increasingly applied for the treatment of diverse gastrointestinal diseases. With regard to reports of a pronounced decrease of intra-abdominal blood flow with increasing intra-abdominal pressure, the present study investigates the impact of pressure and gas type on ischemia in small bowel anastomoses in the rat model. Laparotomy and ileoileal anastomosis were performed in 39 male Sprague-Dawley rats. A CO₂ or helium pneumoperitoneum of 3 mm Hg or of 6 mm Hg was maintained before and after anastomoses. Rats in the control group received no pneumoperitoneum. Animals were sacrificed after 5 d, and the anastomotic region was explanted for subsequent histopathological examinations. In hematoxylin and eosin (HE)-stained sections, the Chiu score, villi configuration, and number of goblet cells were analyzed. Proliferation (Ki67) and expression of a matrix metalloproteinase (MMP-8) were examined by immunohistochemistry. Mucosal damage according to the scoring system by Chiu, the number of goblet cells, the villus length, the proliferation (Ki67), and the submucosal expression of MMP-8 was similar in all groups. Our results suggest that within a certain range of pressures and time, laparoscopic assisted surgery using CO₂ pneumoperitoneum can be performed safely. Helium gas offers no advantages over CO₂.     

Effects of laser-modified versus osteopromotively coated titanium membranes on bone healing: a pilot study in rat mandibular defects

Regeneration of alveolar bone with membrane techniques has become an integral part of implant dentistry. The aim of the present study was to determine if laser-modified titanium membranes are of value in the regeneration of so-called critical size defects in the rat model compared with titanium membranes that were coated with growth factors. A total of 24 rats were included in the study. Critical size defects were created bilaterally and covered by titanium membranes coated with (1) polylactide, (2) polylactide and clindamycin, (3) polylactide and growth factors, (4) polylactide, clindamycin and growth factors and (5) uncoated but laser-modified titanium membranes. All 18 control defects were covered by titanium membranes without any substrate. Four weeks after treatment the animals were killed. Laser-modified titanium membranes (group 5) showed new bone formation in many areas. Nevertheless, complete bridging was found only in one specimen. In contrast, in groups 3 and 4, most defects showed almost complete bridging of the defects. In particular, clindamycin had no inhibitory effect on bone healing. Furthermore, after 28 days, there was no significant difference between the individual groups (including controls) with respect to the total amount of lamellar bone. Growth-factor-coated membranes can significantly accelerate the healing process of bony defects in the rat mandibular model. Nevertheless, it is not possible to accelerate bone healing with laser-irradiated membranes or to enhance the quality of bone within the time period examined.     

The value of laser in the treatment of malignant disease of the larynx

The value of functional and reconstructive surgery to the larynx in the treatment of malignant tumours to preserve residual function as far as possible has been clearly demonstrated. A further step in the development of functional surgery is classical microsurgery of the larynx which facilitates diagnosis and endoscopic microsurgical treatment of benign tumours. However, recently following the introduction of the carbon dioxide (CO₂) laser it has been shown that it is possible to treat also malignant tumours of the larynx by endoscopic microsurgery.An incision made by the photo-thermal CO₂ laser scalpel is characterized by the relative absence of bleeding, lack of post-operative oedema, rapid epithelialization without associated infection or cicatrization and this results in optimal post-operative laryngeal function.This paper presents the results of treatment of selected cases of T1 and T2 carcinoma of the glottis treated by CO₂ laser excision under microlaryngoscopic control.In this series healing was rapid with minimal hospitalization and without a tracheostomy. Excellent functional results were achieved and the patient was able to return rapidly to his original occupation. It is our opinion that at present this treatment modality represents the optimal treatment for T1 and T2 carcinoma of the glottis.     

The treatment of mild endometriosis with laser laparoscopy: a two-step treatment analysis of patients whose primary therapy was successful.

OBJECTIVES: The most advantageous treatment for pelvic endometriosis that is not extensive has long been the subject of debate. In recent years, the ability to detect atypical presentations has allowed the gynecological surgeon to treat this entity more readily. The treatment in the past has been concerned with the singular treatment being applied at the time, not on the prior treatment effects on current therapy. The purpose of the current study was to see whether previous successful treatment modalities affected the success of subsequent laparoscopic laser fulguration treatment of endometriosis. METHODS: Patients who were previously treated for their endometriosis (minimal and mild) and had success in achieving pregnancy were treated for their disease after failing to become pregnant after delivery. They were treated with laparoscopic laser fulguration of the disease and the results were examined by chi-square (chi2) analysis. RESULTS: There appears to be no difference in current pregnancy rates in patients who were successfully treated in the original treatment for endometriosis, no matter which of the therapies had been used. CONCLUSION: If endometriosis is diagnosed at the time of laparoscopy and is easily amenable to treatment, it should be treated at the time of surgery regardless of prior treatment and results.     

The use of laser surgery in subtotal meniscectomy and the effect of low-level laser therapy on the healing potential of rabbit meniscus: an experimental study

The aim of this study was to evaluate the effect of low-level laser therapy on the healing potential of the peripheral rim of rabhit meniscus following laser subtotal meniscectomy, and to compare the subtotal meniscectomy as produced by a surgical blade and by a surgical CO₂ laser. Twenty-four male New Zealand rabbits were divided into three groups (A, B and C). In each animal, a subtotal meniscectomy of the medial meniscus of the right knee was carried out. In Group A, meniscectomy was performed with a surgical blade, and in Groups B and C, a meniscectomy was performed with a CO₂ laser (6 W, 0.1 mm, 0.2 s). The animals of Group C were treated every other day with a GaAIAs diode laser (820 nm, 100 mW, 48 J cm^–2) until death. Two rabbits of each group were killed on the 10th, 20th, 30th and 40th post-operative days. The medial meniscus was removed from all cases, fixed in buffered formalin and embedded in paraffin wax. Subsequently, the sections were stained with Haematoxylin and Eosin as well as with Masson's trichrome, and examined microscopically and morphometrically.This study showed that: (1) fibroblasts and collagen fibrils were more abundant and dense in rabbits of Group C than in rabbits of Groups A and B; (2) after the 20th post-operative day, the granulation tissue was more cellular in Group C in comparison with Groups A and B; and (3) the morphometric evaluation showed that the subtotal meniscectomy with CO₂ laser in Groups B and C caused less tissue damage in comparison with the conventional surgical technique used in Group A. It was concluded that: (1) less damage was produced by a CO₂ laser than by a surgical blade; and (2) the healing potential of rabbit meniscus following laser resection was accelerated with the use of low-level laser therapy post-operatively.