Tomsk Military Medical Institute, Siberian State Medical University, Tomsk, Russia
RELEVANCE: In most cases ureteral stones impair urodynamics and necessitate the urgent removal of them. Until recently most clinics used open surgery for ureteral stone treatment. The introduction of extracorporeal shock-wave lithotripsy made possible the non-surgical re-moval of ureteral stones. The non-invasiveness of this method has made it possible to expand the indications whårå it can be used. However, experience has often shown this method to be ineffective in the case of impacted, nonopaque or large stones, the fragmentation of which leads to the formation of "steinstrasse". In addition, many researchers now find changes oc-curring after the impact of a shock wave on the ureter wall and the surrounding tissues. In most cases, this makes it necessary to use àltårnàtive methods of ureter stone extraction. Con-tact ureterolithotripsy may become the top-priority àltårnative method of urolithiasis treat-ment.
OBJECTIVE: To determine, in clinical practice, the efficacy of contact nanopulse lithotripsy. Another objective is to study experimentally the extent of damage and the period required for bladder and ureteric mucosa recovery after its exposure to an electric pulse.
For the last two years, 68 patients aged 22 to 78 years (26 males and 42 females) underwent ureterolithotripsy in the Urological Department of the Tomsk Military Medical Institute. The concrements were frîm 5 to 12 mm in size and were situated in the upper (12), middle (33), or lower third of the ureter (16), and in the bladder (7). We used the following devices: rigid ureteropyeloscope (R. Wolf 8.5-11.5 Fr), and the MedLine contact nanopulse lithotripter.
The advantages of this device compared to other lithotripters are as follows:
- No limitations regarding the hardness of stones; the availability of a thin and flexible probe.
- Higher safety for patients compared to laser or electrohydraulic lithotripsy; the ability to use it for urolithiasis treatment.
- 80% of stones are destroyed within a few minutes.
- Ability to accurately control the energy that is being transferred to the stone through the probe.
- Compact design, which makes the device portable.
- Lithotripter is easy to maintain - any practicing urologist can use the device without special training.
- In addition, the device is electrically safe for doctor and patient.
Indications for contact ureterolithotripsy were the following: the presence of large ureteral stones (larger than 0.5 cm), long-standing impacted stones disrupting renal function and uro-dynamics; ineffective extracorporeal lithotripsy of ureteral stones (1-2 sessions), presence of "steinstrasse" after shock-wave lithotripsy; unsuccessful attempts at ureteral lithoextraction. The lithotripsy procedure was performed in the operating room under spinal anaesthesia. In order to prevent the formation of "steinstrasse" and the migration of the stone or its fragments up the ureter, the concrement was caught into a basket. Then, the lithotripter probe was ad-vanced to the stone and lithotripsy took place. In 64 cases, complete destruction of the con-crement was achieved. Two patients with bladder stones had to undergo mechanical lith-otripsy because of the partial destruction of the stone, which was due to its hardness. Only 2 patients underwent urgent ureterolithotomy, including stent installation, because of ureter per-foration. In 58.7% of patients, a temporary stent was installed, which was later removed; in 36.5% of cases, transient macrohaematuria was diagnosed, which stopped within 24 hours in 90% of cases without haemostatic therapy. No postoperative complication of pyelonephritis was observed in any case, but short courses of anti-inflammatory therapy were carried out be-fore and after lithotripsy as a preventive measure. In noncomplicated cases, the lithotripsy procedure took 20-30 minutes. Sixty percent of patients were discharged frîm the hospital within 3 days after the procedure, and the other 40% were discharged within 5 days. The re-duction of bed-days economises on medications and expendables.
Contraindications to contact lithotripsy were the following: ureteral strictures below the loca-tion of the stone (2); spinal disorders making it infeasible to position the patient in the chair (1).
The chemical composition of the concrements was analysed, showing that 29.7% of stones were urates, 47.2% - oxalates, 22.4% - phosphates, and 0.7% - cystine stones. The stones varied in composition also differed in appearance and durability. Phosphates are usually ir-regularly shaped, their surface is uneven, the colour of the stones varies frîm grey to white, the hardness is not great, and the stones are easily disintegrated. Oxalates have an uneven sur-face, their colour is usually dark brown, and they are disintegrated relatively well. Urates are usually ball-shaped, smooth, and the colour varies frîm yellow-and-grey to dark red-and-brown. These are the densest stones and they are difficult to disintegrate.
To study the changes in the mucosa of the bladder and the ureter caused by the pulse impact, mature mongrel dogs were used for lithotripsy. The impact on the mucous membrane was ef-fected by the direct contact of an electrode having various values of pulse energy. Material was collected at different times: immediately after exposure, in 24 hours, in 14 days, in 1 month, in 3 months, in 6 months and in 1 year. In the course of the study we used the Micros microscope (Austria), magnifying power of 300 and 600, eosin and haematoxylin stain. The mucosal changes are clearly visible on the material taken immediately after exposure of the mucosa to a discharge, depending on the amount of pulse energy used; one day after exposure we could observe an increase of the haematoma and oedema as compared to the mucosal changes after direct exposure. Six days later, areas of the mucosal sloughing were visible as well as the process whåråby its integrity was undergoing restoration with new cells. There was also a reduction of the swelling and rarefaction of the haematoma. At 14 days after exposure, mucosal changes were clearly visible in the form of epithelial dystrophy, oedema of the surrounding tissues, and weak lymphohistiocytic infiltration. The material taken 1 month after exposure showed the start of the formation of loose connective tissue and a reduction in the amount of oedema. After 3 months, the formed connective tissue was clearly visible on his-tologic sections. But, in no case did these changes lead to stenosis nor did they affect urody-namics. After 6 months, the complete recovery of the mucosa was visible, with areas of con-nective tissue seen in the place of that had been exposed to a pulse having maximum energy values.
1. The study showed that contact nanopulse lithotripsy is less traumatic to the surrounding tissues as compared to other methods of contact lithotripsy.
2. An efficacy evaluation showed there to be a considerable reduction of bed-days, and cost-savings in medications and expendables.
3. The use of this method of contact lithotripsy makes it possible to enhance the efficacy of ureteral stone contact fragmentation owing to the retention of the concrement in a basket, which reduces the risk of concrement migration to the pelvis under the influence of the irriga-tion liquid and the formation of a "steinstrasse". In addition, this method considerably reduces the time of the procedure and the length of the hospital stay of patients.