CO2 laser and suture in splenic parenchyma: an experimental study

Hemisplenectomy was performed with the scalpel in 12 mongrel dogs. The blood vessels of the splenic pedicle were temporarily clamped. In a six-dog group, hemostasis was obtained by CO2 laser and residual bleeding was controlled by sutures. In the other six dogs, group hemostasis was performed only by sutures. The surgical procedure was free of mortality. No hematological changes were observed in both groups. Histological studies revealed a better hemostatic effect and intensive necrosis of the splenic parenchyma in the lasered group compared with the sutured group.     

Poly-L-lactic acid plate for covering of small cranial bone holes: an experimental study in rabbits

Cranioplasty was performed on 13 adult New Zealand white rabbits to investigate the potential of poly-L-lactic acid (PLLA) plates for cover of small cranial bone holes. Two holes of 5 mm in diameter were drilled through the parietal bone, one on each side of the skull. One was covered with a self-reinforced polylactide (SR-PLLA) plate while the other one was left empty, with only the periosteum covering. The results were analysed by taking X-rays and samples for histological examination 3, 6, 24 and 48 weeks postoperatively. There were no special radiological findings. Histologically, new bone formation was clearly seen on the implant side at 24 and 48 weeks after the operation, while there was only a slight reaction on the control side in the same rabbit. We conclude that SR-PLLA appears to enhance the healing of cranial bone. Received: 4 May 1998 / Accepted: 26 October 1998     

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.     

CO2 laser resurfacing and photocarcinogenesis: an experimental study

BACKGROUND AND OBJECTIVES: To examine whether carbon dioxide (CO2) laser treatment has a carcinogenic potential or may influence ultraviolet (UV)-induced carcinogenesis. STUDY DESIGN/MATERIALS AND METHODS: Hairless mice (n = 211) were treated with a Sharplan CO2 laser with FeatherTouch scanner. Simulated solar irradiations were administrated either pre-operatively or pre- and post-operatively. Weekly clinical assessments of skin tumors were performed blinded during the entire observation period of 12 months. RESULTS: No tumors appeared (a) in mice just treated with CO2 laser, (b) in mice exposed to UV irradiation only before CO2 laser treatment or (c) in untreated control mice. Tumors developed in CO2 laser treated mice that were exposed to UV-irradiation both pre- and post-operatively and in UV-irradiated control mice. The time to first, second, and third tumors ranged from 18 to 20 weeks and no significant differences were demonstrated. CONCLUSIONS: CO2 laser treatment does not have a carcinogenic potential in itself, nor does CO2 laser treatment influence UV-induced carcinogenesis.     

Periocular skin reshaping by CO2 laser coagulation

When blepharoplasty is performed by transconjunctival route, sometimes the excess of skin created by overlaxness of the lower lid does not retract to achieve the desired cosmetic result. We propose a method for controlled retraction of the eyelid by coagulating the skin using the CO₂ laser. Thanks to this approach, the lower eyelid's tone recovers and the desired cosmetic appearance is achieved. Results of 37 patients that were treated by 10 W CO₂ laser, 5-mm defocused beam diameter, and pulses of 100 ms, are presented. Follow-up shows that periocular skin reshaping by CO₂ laser for laxened eyelid is a safe method and it can be considered a good alternative of treatment for blepharochalasis without skin excision.     

Ultrapulse 5000C 型超脉冲CO_2激光经结膜入路整复眼袋

为减少术中出血,提高眼袋整复效果,自１９９７年３月以来应用Ｕｌｔｒａｐｕｌｓｅ５０００Ｃ型超脉冲ＣＯ２激光经结膜行眼袋整复术２０４例,其中５２例局部伴有细密皱纹者采用电脑图形发生器（ＣＰＧ）手具进行激光除皱手术。术中出血极少,手术时间缩短,全部病例均获满意效果。对眶脂肪膨隆者用激光经结膜整复效果良好。     

Hemisplenectomy using a hand-held CO2 laser. An experimental study

Hemisplenectomy was performed in mongrel dogs using a hand held CO2 laser. Cutting and hemostasis were performed by a laser beam with a high concentration power--about 6kW/mm2--at the focal spot, and residual bleeding was controlled by using a defocused beam. The cutting action was improved by temporary closing of the arterial vessels and by injecting adrenaline into the splenic artery to produce a relatively dry surface. The surgical procedure was free of mortality or morbidity. Histological studies revealed a brand of fibrous tissue at the cut surface, without apparent abnormalities in the splenic parenchyma beneath the section. Activity of the residual half spleen was shown by postoperative technetium scan and by the fact that Howell-Jolly bodies appeared in peripheral blood only after resection of the remaining half spleen.     

Contact fibre Nd: YAG laser for partial nephrectomy: experimental study in pigs

Summary Thirty-two partial nephrectomies were performed without renal cooling on 13 pigs with a contact fibre Nd: YAG laser (10 W) or a steel scalpel with or without a vascular pedicle clamp. Nine pigs had a 2-week follow-up with an abdominal ultrasound 1 week postoperatively. The time for haemostasis was 6.9±5.8 min (mean ±SD) with the laser and 9.1±5.8 min with the steel scalpel when the clamp was used (P=0.028). There was no significant difference in the total operating time (13.2±4.5 min with the laser vs 12.6±4.6 min with the steel scalpel, P=0.203). Intraoperative blood loss was similar in the two groups when the clamp was used. Clamping the renal pedicle decreased the blood loss by 61% in the laser group and 31% in the steel scalpel group. The number of ligatures used was significantly lower in the laser group (3.7±2.6) compared with the steel scalpel group (6.6±3.4) (P=0.013). Five urinomas developed on the laser side and four on the steel scalpel side. These results indicate that the contact fibre Nd:YAG laser method can be used in partial nephrectomy, but it offers no definitive advantage over the conventional technique.     

Low-energy CO2 laser intestinal anastomosis: an experimental study

Intestinal anastomosis was performed in 17 Wistar rats via tissue welding by the low-energy CO2 laser. The postoperative course in the animals studied was uneventful. The integrity of the anastomosis was investigated manometrically, immediately upon completion of the anastomosis as well as 20 days later. Ten additional Wistar rats served as controls in which conventional interrupted one-layer anastomosis was performed. The results show a significant superiority of the intestinal anastomoses that were constructed by means of laser tissue welding. The time to complete the anastomosis was also significantly shorter when laser rather than manual suturing was used. Serial histological examinations for up to 90 days following surgery revealed complete healing and epithelization of the anastomotic site.     

A study of actinic cheilitis treatment by two low-morbidity CO2 laser vaporization one-pass protocols

Therapeutic approaches to chronic actinic cheilitis focus on the removal or destruction of diseased epithelium. The CO₂ laser has become an important therapeutic alternative, achieving clinical resolution in around 90% of patients. Although many laser physical parameters have been reported, some are known for their low potential for scar induction without compromising the success of the results. The aim of this clinicohistological study was to compare the therapeutic responses to two low-morbidity protocols involving a single laser pass. A total of 40 patients with chronic multicentric and microscopically proven disease were randomly submitted to two conservative CO₂ laser protocols using a bilateral comparative model. The degree of histological atypia of the epithelium was determined in 26 patients both pre- and postoperatively for both protocols. Other histological phenomena were assessed in addition to this central analysis parameter. Clinical recurrence occurred in 12.5% of patients for each protocol, together with a significant reduction in the degree of epithelial atypia (p < 0.001), which was occasionally complete. However, no difference was found between the protocols (p > 0.05). Using these morphological parameters it was not possible to determine whether postoperative epithelial atypias in part of the sample were reactive or residual in nature. A few patients may show minor postoperative lesions. Due to their potential to achieve clinical and importantly microscopic resolution, the studied protocols may be used for mild through moderate dysplastic epithelium and clinically diffuse disease.

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.     

Anesthesia for surgery related to craniosynostosis: a review. Part 2

The management of children with craniosynostosis is multidisciplinary and has evolved significantly over the past five decades. The treatment is primarily surgical. The anesthetic challenges continue to be the management of massive blood transfusion and prolonged anesthesia in small children, often further complicated by syndrome‐specific issues. This two‐part review aims to provide an overview of the anesthetic considerations for these children. The first part described the syndromes associated with craniosynostosis, the provision of services in the UK, surgical techniques, preoperative issues and induction and maintenance of anesthesia. This second part will explore hemorrhage control, the use of blood products, metabolic disturbance and postoperative issues.     

CO2 laser annular thermokeratoplasty: a preliminary study.

Since most techniques of refractive surgery currently in use or being developed have the potential for significant side effects, there is a need for investigating alternative procedures. We herein report on the use of a pulsed CO2 laser beam delivered through a pair of complementary axicons to produce a ring of stromal collagen contraction resulting in the flattening of the corneal apex of cadaver eyes. Irradiances of 29 W/cm2 and 23 W/cm2 were used for rings of 5.5 mm and 7.0 mm, respectively. The creation of a ring of 7.0 mm in diameter did not affect the corneal curvature significantly but when the diameter was reduced to 5.5 mm, substantial flattening proportional to the dose of radiation took place. In our system, it was possible to achieve up to 11.3 diopters of mean keratometry flattening (90 joules, 5.5 mm of diameter). In addition, a 1 mm posterior displacement of the corneal dome without histological evidence of closure of the iridocorneal angle was observed. Annular thermokeratoplasty (ATK) may minimize side effects encountered with other refractive procedures since it does not require ablation, incisions, or interaction with the central optical zone.     

Effects of intra-abdominal CO2-insufflation on normal and impaired myocardial function: an experimental study

BACKGROUND: Intra-abdominal pressure (IAP) elevation during CO2-pneumoperitoneum increases cardiac afterload and may enhance dysfunction of the already compromised heart. This study focused on the effects of acute IAP increases on left and right ventricular loadings and contractility in the heart with impaired global function. METHODS: Impairment of myocardial function (IMF) was pharmacologically induced in 16 pigs by administration of halothane and propranolol, while baseline arterial pressure was maintained by intravenous phenylephrine. Intra-abdominal pressure was gradually increased by 10 mmHg up to 30 mmHg in the supine position (IMF group 1, n = 8) or in a head-down tilted position (IMF group 2, n = 8). In two control groups with normal myocardial function, IAP was also increased in the supine position or the head-down tilted position. Cardiac function in all groups was assessed by epicardial echocardiography, intraventricular pressure measurements and pulmonary artery catheterization. RESULTS: The increase in IAP was accompanied by a transient rise in LV end-systolic wall stress and reduced cardiac output significantly by 16-24% in all groups. In the IMF groups, LV end-diastolic transmural pressure increased by 34-60% to peak values of 24 mmHg, while cross-sectional LV end-diastolic areas remained unchanged. Increases in right ventricular end-diastolic volume and decreases in right ventricular ejection fraction as well as in cardiac output were most pronounced at IAP 20 mmHg and significantly stronger in both IMF groups than in the control groups (P < 0.001). CONCLUSION: Following the acute elevation of IAP, the right ventricular volume load shifted more extensively in the IMF groups than in the animals with normal myocardial function. Myocardial function in the impaired heart may worsen during IAP elevation due to right ventricular load alterations rather than a LV afterload increase.     

Partial splenectomy with CO2 laser: An experimental study

A freehand carbon dioxide laser is now available for surgical procedures. A comparison of its utility with the electrocautery was carried out in five dogs by the performance of hemisplenectomy. All dogs survived without complications. The laser proved to be an effective instrument for partial splenectomy under the terms of the experiment.     

Bone repair following bone grafting hydroxyapatite guided bone regeneration and infra-red laser photobiomodulation: a histological study in a rodent model

The aim of the investigation was to assess histologically the effect of laser photobiomodulation (LPBM) on a repair of defects surgically created in the femurs of rats. Forty-five Wistar rats were divided into four groups: group I (control); group II (LPBM); group III (hydroxyapatite guided bone regeneration; HA GBR); group IV (HA GBR LPBM). The animals in the irradiated groups were subjected to the first irradiation immediately after surgery, and it was repeated every day for 2 weeks. The animals were killed 15 days, 21 days and 30 days after surgery. When the groups irradiated with implant and membrane were compared, it was observed that the repair of the defects submitted to LPBM was also processed faster, starting from the 15th day. At the 30th day, the level of repair of the defects was similar in the irradiated groups and those not irradiated. New bone formation was seen inside the cavity, probably by the osteoconduction of the implant, and, in the irradiated groups, this new bone formation was incremental. The present preliminary data seem to suggest that LPMB therapy might have a positive effect upon early wound healing of bone defects treated with a combination of HA and GBR.     

The role of pulse length in limiting distant damage to vascular tissue caused by the Nd-YAG laser

The total damage caused by equivalent doses of energy given to human cadaver vascular tissue over the same time scale from three Nd-YAG lasers of different pulse lengths is quantified. The continuous wave (c.w.) laser produces vacuolation and coagulation around a vaporized crater; the 100 μs pulsed laser produces less surrounding damage and the 10 ns pulsed laser none at all. The areas of damage in five craters made with 10 J energy were measured from histology slides using a digitising platten, and it was found that in each case the total amount of damage was the same, even though the depth of the craters made varied. The dose response for vaporization of the 10 ns pulsed laser was the greatest at 35 μm/J and that of the c.w. laser was least at 8 μm/J. A pulse length of 100 μs may not be the optimum for limiting surrounding tissue damage during laser angioplasty but it produces much less damage than a c.w. laser and unlike the 10 ns pulses is easily transmissible down an optical fibre.     

A new method of vascular anastomosis by CO2 laser: experimental and clinical study

It is difficult to maintain the long-term patency after conventional anastomosis especially for the small caliber vessels. Since 15 years we have performed aortocoronary bypass with suture materials for the patients with ischemic heart disease. There are some problems in maintaining the long-term patency of the bypass grafts. Low energy CO2 laser was utilized to make vascular anastomosis with a few stay sutures. Vascular anastomoses (side-to-side, end-to-end, end-to-side) were carefully made by CO2 laser in the regions of the femoral arteries and veins, the carotid arteries and jugular veins in dog. A-C bypass was also successfully carried out between the internal mammary artery and the left anterior descending artery under the beating heart in experiment. Outputs of 20-40 mW and irradiation times of 6-12 sec/mm were optimal conditions for anastomosis of the small caliber vessels. There were no problems in the intensity and the healing of the anastomotic sites in comparison with the conventional suture method. On the basis of these excellent experimental results a low energy CO2 laser was employed clinically for vascular anastomosis of the peripheral vessels in 28 patients with angina pectoris or chronic renal failure and cardiac failure. There were no complications such as bleeding and suture line aneurysm after surgery. In conclusion, vascular anastomosis by laser might be recommended in performing with safety and rapidity for small caliber vessels.     

Partial nephrectomy with a combined CO2 and Nd:YAG laser: Experimental study in pigs

Twenty-eight partial nephrectomies were performed on nine pigs with a simultaneous, coaxial CO₂-Nd:YAG laser at power settings of 20 W and 40 W, or with a steel scalpel. A vascular pedicle clamp was used without renal cooling. The time for hemostasis was 4.5 ± 3.2 min (mean ± SD) with the laser and 6.4 ± 2.5 min with the steel scalpel (P = 0.064). There was no difference in the total operation time (10.4 ± 3.5 min with the laser vs. 11.0 ± 3.2 min with the steel scalpel, P = 0.470). The mean blood loss with the laser was 17.5 ± 6.7 g and 22.1 ± 15.2 g with the steel scalpel (P = 0.299). The number of ligatures needed for complete hemostasis was 2.9 ± 2.1 with the laser and 5.0 ± 2.3 with the steel scalpel (P = 0.011). The average thermal damage was 0.23 ± 0.10 mm. It is concluded that the simultaneous CO₂-Nd:YAG laser method can be used in partial nephrectomy and it offers better hemostasis than the conventional technique. Further studies with different power levels are needed. © 1994 Wiley-Liss, Inc.     

Comparison of oedema formation after CO2 and Nd-YAG laser therapy and cryosurgery

A comparison of oedema formation, as measured by leakage of the dye Evans blue from the circulation, was carried out in the laboratory rat employing standardized lesions on the anterior abdominal wall by various regimens of CO₂ laser, Nd-YAG laser and cryosurgery over a 4 h period. The CO₂ laser at high power produced significantly less oedema than any other modality (p<0.05) while the Nd-YAG laser at high power produced significantly more (p<0.05) than any other. Nd-YAG low power, cryosurgery in one of two freezes and the CO₂ laser at low power all produced a moderate degree of oedema (no significant difference). These findings have particular clinical relevance in sites where oedema may cause major functional or cosmetic problems as in the oro-facial region. The animals remained sedated over the period of observation so that any possible discomfort was eliminated.