Factors Affecting the Efficacy of Ureterorenoscopic Holmium: YAG Laser Lithotripsy in Ureteral Stones

Year 2023, Volume: 15 Issue: 3, 155 - 163, 30.09.2023

Nadir Kalfazade

https://doi.org/10.54233/endouroloji.20231503-1353544

Abstract

Objective: Holmium:Yttrium Aluminum Garnet (YAG) laser for ureterorenoscopic lithotripsy (URS-LL) is the gold
standard. The most important factors affecting laser lithotripsy are stone volume, stone density, location of the stone,
laser settings and properties of the laser fiber. We aimed to measure the predictive factors affecting the efficiency of
lithotripsy with objective methods.
Materials and Methods: Between October 2020-February 2022 ureterorenoscopic laser lithotripsy (URS-LL) cases
performed for ureteral stones in the our hospital. It was examined retrospectively. Patients with remaining clinically
significant stones were not included in the study. Holmium:YAG laser 550 μm fiber was used. Demographic data of the
patients, stone size, stone volume, stone density (hounsfield unit -HU) was recorded. The energy (joule-J), frequency
(hertz-Hz), power (watt) values and total lasing time of the patients determined and the total laser energy amount was
calculated. After the data is obtained, the total amount of energy is divided by the stone volume and the amount of
energy required to fragment 1 mm³ stone (J / mm³) was calculated. Additionally, dividing the stone volume by on total
laser time, fragmented stone volume per second (mm³ / sec) was calculated.
Results: Energy, frequency and power did not differ significantly (p>0.05) between groups with laser duration ≤240 sec
and >240 sec. Stone volume, stone HU value, total energy, and energy used to fragment 1 mm³ stone were significantly
higher in the group with laser duration >240 sec than in the group with laser duration ≤240 sec. The fragmented stone
volume in 1 second (mm³/s) in the group with laser duration >240 sec was significantly lower than the group with laser
duration ≤240 sec. Significant efficacy of stone 1050 HU cut-off value was observed in the differentiation of patients
with laser duration ≤240 sec and >240 sec. In the group with total energy >2750 J, stone volume, stone HU value, total
energy, and energy used to break 1 mm3 stone were significantly (p<0.05) higher than in the group with total energy
≤2750 J. In the group with total energy >2750 J, the fragmented stone volume in 1 second (mm³/sec) was significantly
(p<0.05) lower than in the group with total energy ≤2750 J.
Conclusion: In order to determine the effectiveness of laser lithotripsy more objective data is needed, such as
fragmented stone volume in 1 second (mm³/s) and the amount of energy required to the fragment 1 mm³ stone (J/
mm³).

Keywords

Ureteral Stone, Holmium:YAG Laser Lithotripsy, Joule, Frequency

Ethical Statement

Bakırköy Dr.Sadi Konuk Training and Research Hosptial Ethics Committee (2020-351).

Üreter Taşlarında Üreterorenoskopik Holmiyum: YAG Lazer Litotripsi Etkinliğini Etkileyen Faktörler

Abstract

Amaç: Üreterorenoskopik lazer litotripsi (URS-LL) için Holmium:Yttrium Aluminum Garnet (YAG) lazer altın standarttır.
Lazer litotripsiyi etkileyen en önemli faktörler taş hacmi, taş yoğunluğu, taşın konumu, lazer ayarları ve lazer fiberinin
özellikleridir. Biz bu çalışmada lazer litotripsi verimliğini etkileyen prediktif faktörleri objektif yöntemlerle ölçmeyi
amaçladık.
Gereç ve Yöntemler: Ekim 2020- Şubat 2022 tarihleri arasında kliniğimizde üreter taşları için yapılmış URS-LL
vakaları retrospektif olarak incelendi. Klinik anlamlı rezidü taşı kalan hastalar çalışmaya dahil edilmedi. Hastalar için
Holmiyum:YAG lazer 550 μm fiber kullanıldı. Hastaların demogafik verileri, taş boyutu, taş hacmi, taş yoğunluğu
hounsfield ünitesi (HU) olarak hesaplandı. Hastaların enerji ( joule-J), frekans (hertz-Hz), güç (watt) değerleri ve toplam
lazer kullanım süreleri kayıt edilerek toplam lazer enerji miktarı saptandı. Bu veriler elde edildikten sonra toplam enerji
miktarı taş hacmine bölünerek 1mm³ taşı parçalamak için gerekli enerji miktarı (J/mm³) hesaplandı. Ayrıca taş hacmi
toplam lazer süresine bölünerek saniyede parçalanan taş hacmi (mm³/sn) hesaplandı.
Bulgular: Lazer süresi ≤240 sn ve >240 sn olan gruplar arasında enerji, frekans, güç anlamlı (p>0.05) farklılık
göstermemiştir.Lazer süresi >240 sn olan grupta taş hacmi, taş HU değeri, toplam enerji, 1 mm³ taşı parçalamak İçin
kullanılan enerji, lazer süresi ≤240 sn olan gruptan anlamlı olarak daha yüksekti. Lazer süresi >240 sn olan grupta 1
sn’de kırılan taş hacmi (mm³) lazer süresi ≤240 sn olan gruptan anlamlı olarak daha düşüktü. Lazer süresi ≤240 sn ve
>240 sn olan hastaların ayrımında taş 1050 HU kestirim değerinin anlamlı etkinliği gözlenmiştir. Toplam Enerji >2750 J
olan grupta taş hacmi, taş HU değeri, toplam enerji, 1 mm³ taşı parçalamak için kullanılan enerji toplam enerji ≤ 2750
J olan gruptan anlamlı (p<0.05) olarak daha yüksekti. Toplam enerji >2750 J olan grupta 1 sn’de parçalanan taş hacmi
(mm³/sn) toplam enerji ≤ 2750 J olan gruptan anlamlı (p<0.05) olarak daha düşüktü.
Sonuç: Lazer litotripsinin etkinliğini ölçmek için bir saniyede parçalanan taş miktarı (mm³/sn) ve 1 mm³ taşı
parçalamak için gerekli olan enerji miktarı (J/mm³) gibi daha objektif verilere gereksinim vardır. Bu verilerin bilinmesi
üreterorenoskopik lazer litotripsi etkinliğini artırmada prediktif bir faktör olabileceği düşünülmektedir.

Keywords

Üreter Taşı, Ho:YAG Lazer Litotripsi, Joule, Frekans

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