Hans-Peter Berlien

Lasers in Pediatric Surgery

During the last few years the laser has become a very interesting instrument in pediatric surgery. This is the result of the wide variation in tissue interactions and the possibility of specific applications. The CO2 laser is a highly precise cutting instrument whereas the argon laser has its great advantage in the treatment of superficial vascular anomalies. The most important laser in pediatric surgery is the Nd:YAG laser, on the one hand because its radiation can be transmitted by fibres, on the other because with the relationship between interaction time and power density, and the choice of application, it is possible to change the tissue interaction from precise cutting to specific coagulation and homogeneous coagulation. As a result, indications for lasers in pediatric surgery range from the treatment of superficial haemangiomas to typical endoscopic procedures and the resection of parenchymatous organs and tumours.

Laser Treatment of Cutan and Deep Vessel Anomalies

Haemangioms are the most often occuring malformations in childhood and their treatment is controversial. Most haemangioms heal spontaneously before the age of 8, and it is advisable to wait till then. If located at an exposed position, e.g. on the face or on functionally important structures, further growth can result in significant functional disorders or disfigurations. This requires early treatment in infancy and childhood. Until now all treatment methods have been radical and have caused further injury. One prominent example is X-ray therapy. Treatment can result after a period of 20–30 years can result in a development of malignomas (Fig. 1 + 2).

Ten years of laser treatment of congenital vascular disorders: techniques and results

During the period of January 1984 - July 1993, we have treated 611 children with more than 2000 lesions of congenital vascular disorders (CVD) such as hemangiomas and vascular malformations. This number does not include the patients with port wine stains, which also have been treated by means of laser. Most of the CVD patients (n equals 467) presented hemangiomas of the face, the anogenital region, and the extremities, some were located in the trachea or mouth or in the urogenital tract. All of these hemangiomas were growing prior to intervention or showed complications such as bleeding, ulceration, superinfection, or obstruction. Nearly a quarter (n equals 144) of the patients presented vascular malformations, either of singular vessel type involvement or of mixed vascular genesis (venous, arterio- venous, veno-lymphatic or lymphatic) with various complications like tracheal obstruction or recurrent thrombophlebitis. According to our step program, which is based on a clinical classification, the hemangiomas were treated as early as possible, while the vascular malformations were only treated with laser when no other therapeutic technique (embolization, resection) was suitable. All patients were referred for laser treatment from other centers. The lasers used were Nd:YAG and Argon lasers with transcutaneous application with or without continuous ice-cube surface cooling or interstitial laser application. The treatments were performed either on in- or outpatient basis according to age, localization and with good to excellent results in most cases and a complication rate of less than 2%.

Laser Therapy of Haemangiomas and Vascular Malformations – Techniques and Strategies

Summary Lasers have been used in the treatment of haemangiomas since the early 1980s. Several study groups have reported good results, others have been less enthusiastic and emphasized other treatments like cryosurgery. We reviewed our experience with the use of laser therapy in treating complicated haemangiomas of infants. During a 15-year period, 1117 infants with haemangiomas were treated with the Nd:YAG laser. The lesions reported were particular troublesome because of significant cosmetic disfigurement, maceration or ulceration, bleeding, and of potential functional impairment. Superficial findings were treated using was a transcutaneous application with local ice cube cooling to protect the overlying skin. All deep-seated lesions were treated with interstitial laser irradiation. In trachaeal haemangiomas endoscopic laser destruction is an alternative to tracheostomy with good functional results and comparable or less morbidity. Overall, excellent results were achieved in 41% of infants and good results occured in 51%. On the basis of our results we conclude that laser therapy may successfully prevent enlargement and promote involution of haemangiomas with minimal adverse effects. Therapy should be initiated as early as possible, when lesions are relatively flat, for optimal results.

Development of an application set for intraoperative and percutaneous laser-induced interstitial thermotherapy (LITT)

A variable application-set was developed to enable a safe and effective LITT treatment. The set consists of various laser applicators, a protecting catheter and an introducing equipment. The laser applicator was developed with different radiation patterns to match the topological conditions of the diseased area. For MRI-controlled LITT treatments a special marker is mounted at the distal end of the glass fiber which facilitates its localization. To increase the patients safety a special protecting catheter was designed which is temperature stable up to 250 degree(s)C and transparent for NIR-radiation. The catheter can be placed into the diseased area using the introducing equipment which consists of modified parts of standard interventional radiology equipment. The laser applicator is finally guided through the protecting catheter so that there is no direct contact between applicator and tissue. The system can be used both for intraoperative and for percutaneous treatments.

Laser-induced thermotherapy of benign and malignant tumors controlled by color-coded duplex sonography

Since 1984 we use the interstitial application of laser induced thermotherapy (LITT) for the treatment of congenital vascular disorders (CVD) such as hemangiomas and vascular malformations. In most of the procedures a 600 micron core bare fiber is used to deliver the radiation of a cw Nd:YAG laser emitting at 1064 nm into the diseased tissue. As most of the CVD treated this way are located subcutaneously, the localization of the fiber and the interstitial laser coagulation (ILC) is controlled by transillumination and palpitation of the heat expansion of the skin surface, this way a crepitation can also be detected during the ILC. As the ILC in deeper body structures cannot be controlled directly we use color coded duplex sonography (CCDS), both for diagnostic and treatment control. In the procedures where we use the B-scan image for puncture control, a color signal is displayed representing tissue movements. These movements caused by degasification and vapor are those detectable as crepitations when using direct control. The color signal starts, changes, and moves in a reproducible pattern following the heat distribution and the subsequently occurring degasification in the tissue. Also the changes in perfusion are detectable by the means of CCDS. The precise extent of the coagulation is visible in the B-scan several minutes after laser exposure. The clinical experience and an extensive experimental evaluation has proven that CCDS is a valuable real time method to monitor the tissue reaction in ILC-procedures. For two years we have performed ILC-procedures with CCDS control in patients with CVD (n equals 65) successfully. Because of its reliable imaging and the clinical advantages recently we applied this type of ILC-control to the palliative treatment of nonresectable primary and secondary liver tumors (n equals 3) and subcutaneous metastases of mamma carcinoma. (n equals 6).

Pharmacokinetics of the far red absorbing octa-alpha-butyloxy-zinc phthalocyanine in Lewis lung carcinoma bearing mice

The newly synthesized potential photosensitizer octa-(alpha) -butyloxy-zinc phthalocyanine (8-(alpha) -bo-ZnPc) is characterized by a high absorption coefficient at the far red wavelength 735 nm and a good singlet oxygen quantum yield. The pharmacokinetics of 8- (alpha) -bo-ZnPc were studied on the Lewis lung carcinoma in mice after i.v. administration of 7.8 micrometers ole/kg body weight solubilized in PBS with 1% Tween 80 at 2, 6, 12, 24, 48 and 168 hour incubation intervals. The accumulated dye contents were chemically extracted from selected tissues and the concentrations were measured by absorption spectroscopy. The parenchymatous organs, liver and spleen, showed maximum 8-(alpha) -bo-ZnPc concentrations after 6 h incubation (33 nmole/g liver and 5 nmole/g spleen, respectively). An extensive uptake was detected in the lung where concentrations higher than 90 nmole/g tissue were measured in the 6, 12, 24, and 48 hour extracts. The malignant tissue did not accumulate higher 8-(alpha) -bo-ZnPc concentrations than 0.4 nmole/g tumor during the entire investigation period. The dye contents extracted from muscle, representing normal tumor surrounding tissue, and skin were even lower and never exceeded 0.11 nmole/g muscle (6 h) and 0.21 nmole/g skin (2 h), respectively.

Pharmakokinetics of 132-hydroxy-bacteriopheophorbide: a methyl ester studied by fluorescence spectroscopy on Lewis lung carcinoma bearing mice

The pharmacokinetics of 132-hydroxy-bacteriopheophorbide a methyl ester (OH-BPME) was studied on Lewis lung carcinoma bearing mice by fluorescence spectroscopy. The sensitizer distribution in different organs and in the tumor was investigated in dependence on the incubation time. A very fast cleaning of the blood and the skin was observed. The results of our investigations suggest that PDT using OH-BPME could be effective at sensitizer incubation times of about 12 h.

Laser Application in Pediatric Urology

Diseases of the urologenital tract in childhood are very different from these of adults. At adults mostly we have tumors, at children there are in addition to that congenital malformations and also traumatic conditioned diesease. This wide spectrum of diseases in pediatric urology performs a manifold use of different laser systems, where especially the Nd:YAG laser became qualified because its radiation can be transmitted by fiber without any problem (Fig. 1).

Multispectral fluorescence imaging device for malignancy detection

In medical diagnosis of superficial lesions at inner or outer surfaces of the human body fluorescence imaging techniques are able to deliver additional information on the metabolic and structural state of the observed tissue. To subtract background fluorescence and to achieve a differential diagnosis a multispectral analysis in several wavelength windows is needed. Additionally, special image algorithms have to be applied which depend on the examined malignancy. For this purpose a multispectral fluorescence imaging device was developed. It can be used both endoscopically and in combination with a standard operational microscope from Carl Zeiss, Germany. In this paper, the device and first clinical results are presented. The device was built to detect superficial lesions like tumors, inflammations, etc. Target chromophores are NADH, Protoporphyrin IX, collagen and other. The measured optical bands are (405 plus or minus 5) nm, (442 plus or minus 5) nm, (458 plus or minus 5) nm, (550 plus or minus 5) nm, (630 plus or minus 5) nm and (690 plus or minus 5) nm. A special UV-source with a liquid light guide is used as the illumination source in two excitation bands of (365 plus or minus 10) nm and (420 plus or minus 20) nm. First clinical investigations of superficial malignancies like squamous cell carcinoma and basalioma are presented.