Functional and histological restitution in the urinary tract after Nd:YAG laser coagulation

Treatment of Urethral Syndrome: A Prospective Randomized Study with Nd:YAG Laser

INTRODUCTION

The urethral syndrome is characterized by irritative disturbances, the urgency-frequency syndrome and/or pain associated with negative urine cultures. Areas of metaplasic tissue in the trigonal-bladder neck region (trigonitis) are sometimes present. We performed a comparative randomized study to assess the efficacy of side- or end-firing neodymium (Nd):YAG laser surgery in destroying metaplasia and relieving symptoms.

MATERIALS AND METHODS

Between January 1997 and December 2003, 62 consecutive women with the urethral syndrome and squamous metaplasia of the bladder neck-trigone, who were refractory to drugs, were randomly assigned to treatment with end-firing (group A) or side-firing (group B) Nd:YAG laser. Three, 6 and 12 months after surgery all patients underwent a clinical urological examination and cystoscopy. Surgery was considered successful when patients reported they were satisfied with the outcome or stated on the UDI-6 questionnaire that symptoms were reduced by at least 75%.

RESULTS

Group A end-firing laser: patients rapidly improved (2-3 weeks) but symptoms worsened within 3 months. At 6-12 months, symptoms had improved in 19% of the 31 patients and remained unchanged or worsened in 81%. Group B side-firing laser: irritative disturbances worsened in the 7-10 days after therapy but markedly improved within 2-3 months. Symptoms significantly improved in 68% of the 28 patients and remained unchanged or worsened in 32%. Results were significantly better after side-firing laser (p < 0.001) and a trend towards improvements emerged as the joule levels rose. At 3 months, cystoscopy and biopsy showed squamous metaplasia was no longer present in patients whose symptoms had improved. Whitish areas were still present in the bladder neck-trigone in patients whose symptoms had remained unchanged or worsened. These patients were retreated.

CONCLUSIONS

In the treatment of the urethral syndrome the few reports on attempts to restore a normal urothelium by means of diathermocoagulation and cryotherapy have been encouraging. Side-firing laser, which produces necrotic coagulation followed by reconstitution of normal functional epithelium, was significantly more successful than end-firing and was associated with a 78% success rate. These results are encouraging in patients who are usually refractory to medical therapy.

The rat esophagus: ultrastructure and radiological aspects of tissue response after 1320 nm Nd:YAG laser irradiation

Morphological tissue response towards laser treatment was investigated in the esophagi of adult Wistar rats by light- and transmission electron microscopy. The specimens were fixed by perfusion immediately, 2 days and 14 days after laser treatment in order to assess different stages of the healing process. The epithelium of the lasercentre was completely destroyed in the immediate group. The connective tissue showed damaged cells, fused collagenous fibres and occluded blood vessels. Smooth muscle cells presented a vacuolated sarcoplasm and pycnotic nuclei. The cross striation of skeletal muscle cells had disappeared and their nuclei were karyolytic. In a distance of 4 mm from the lasercentre all wall tissues had an almost normal appearance. After 2 days the morphological feature of the lasercentre was the same as in the immediate group. In a distance of 2 mm some layers of flat and intact epithelial cells were observed below the necrotic epithelium. The adjacent connective tissue was infiltrated by inflammatory cells. After 14 days the formation of granulation tissue had caused an occlusion of the lumen in the lasercentre. In a distance of 2 mm the lumen was patent and the wall tissues had been partly restored. As the rat esophagus serves as a model for esophagotracheal fistulae in newborn children we assume the 1320 nm Nd:YAG laser to be a possible application in occlusion of these fistulae.