Pure ultrasonography-guided radiation-free percutaneous nephrolithotomy: report of 357 cases

Currently the most common method to treat large or complicated renal stones that cannot
be managed by shock wave lithotripsy (SWL), is PCNL (Karami et al. 2010]). To perform the PCNL, proper PCS puncture is a crucial step. Using fluoroscopy during
this method is accompanied by exposing the operators including the surgeons as well
as the patients to radiation. Such radiations may lead to hazardous effects on various
organs including the gonads, bone marrow, eyes, and thyroid (Gamal et al. 2011]). Of the organs, gonads are more sensitive as spermatogonia in the male testis are
highly affected by the radiation. It has been reported that even a small dose of 0.15 Gy
can lead to low sperm count. And if the radiation increases to more than 0.5 Gy, transient
azoospermia may occur. Sterility has also been reported by exposure to high doses
of radiation (5–6 Gy) (Hall and Giaccia 2006]).

Access to the PCS can be done by using fluoroscopy, US, or a combination of both techniques.
The best tract to be approached is the direct path, which is from the skin through
the papilla of the desired calyx and renal pelvis (Agarwal et al. 2011]). This approach can be performed by using either the fluoroscope or US. However of
the advantages of using US is guiding the puncture needle to the posterior calyx without
any considerable complications (Gupta et al. 1998]). US is also the preferred option for those patients for whom cystoscopy and/or ureteric
catheterization are impossible. It is also a good option for pregnant women who are
scheduled for PCNL (Agarwal et al. 2011]). Osman and colleagues reported 315 PCNLs guided by US that they performed during
1987–2002. They punctured the PCS under the US guidance, but the dilation of tract
was guided by fluoroscopy, while the patients were in a prone position. They reported
50.8% complication rate, although most of them were not clinically significant. They
achieved 96.5% stone-free rate using the US-guided renal access (Tiselius et al. 2001]). Desai and co-workers reported the advantages of using US to puncture PCS. They
also believed that this techniques not only can help surgeon to avoid radiation, but
also visceral injury, and intra-renal vascular damages can be prevented too. They
concluded that straight access toward the PCS, which can be achieved using US may
lead to lower morbidity (Desai 2009]).

Etemadian and colleagues assessed the safety and efficacy of transcutaneous nephrolithotomy
guided by US in 12 patients during December 1999–December 2000. Of the patients, 11
patients were stone-free after 3 months. They recommended using US in patients whose
PCS were dilated and had large stones in renal pelvis or calyx. (Etemadian et al.
2004])

We have also documented the feasibility, reliability, safety, and effectiveness of
US-guided PCNL over fluoroscopy in a study done from August 2003 to December 2007
(Hosseini et al. 2009]). Basiri and colleagues reported their experience of performing PCNL guided by US
in 30 patients who were in flank position. They reported 88.9% stone-free rate in
patients who had a single calculus and 75% in patients who had staghorn or multiple
calculi. The researchers concluded that US-guided PCNL could have acceptable outcomes
without considerable complications in comparison with the standard technique (Basiri
et al. 2008a]).

In another study, Basiri and colleagues reported the results of their trial on 100
patients without upper urinary tract abnormalities. They concluded lower exposure
to radiation and access duration in patient who underwent PCNL guided by US compared
with those received fluoroscopy-guided access (Basiri et al. 2008b]). In another randomized trail on 40 patients, Karami and co-workers showed successful
US-guided PCNL in all their patients who were positioned in lateral decubitus flank.
They reported safety and efficacy of US-guided PCNL as their complete stone-free rate
was 85%. They suggested using this technique in the lateral decubitus flank position
to prevent hazardous effects of radiation to patients, surgeons, and surgical team
(Karami et al. 2009]). Agarwal and others also reported shorter mean time for successful puncture and
radiation exposure in their patients who underwent puncture guided by US. Their technique
yielded complete stone clearance with no considerable morbidity (Agarwal et al. 2011]). In another study 100% successful access to PCS was reported by Gamal and colleagues.
Their approach to the PCS was through the most convex point to prevent vascular damage;
hence no intraoperative bleeding was reported. Only two cases of PCS perforation (5.9%)
during dilatation by metal dilators was reported, which could be resulted from the
difficulty in simultaneous monitoring of the metal dilator and the tip of the central
metallic bar (Gamal et al. 2011]). In a study on 92 patients, Zhou and colleagues reported the need for a second tract
in 22.8% of their patients. They mentioned that the reason for their finding was that
about two-thirds of their patients had multiple and staghorn stones (Zhou et al. 2008]).

Song Yan and co-workers reported 705 cases of PCNL by pure sonography. They showed
92.6% stone-free rate in single stone and 82.9% in staghorn or multiple cases (Yan
et al. 2013]).

In our study, the total stone-free rate was 94.4%, with no significant morbidity (Table 2). Access failure occurred in ten morbidly obese patients for whom we had to use fluoroscopy.
In 15 patients the PCS was perforated (4.2%) during dilatation, which is in accordance
with the report by Gamal and colleagues who reported perforation in two (5.9%) patients.

Although US-guided PCNL has many advantages, such as the high success rate for PCS
puncture, intra-operative detection and monitoring of both radiolucent and radiopaque
stones, lower risk of radiation exposure, and the ability to monitor all organs in
the path of the puncture; it should be considered that it is an operator-dependent
procedure, and to perform PCNL guided by US, sufficient experience must be acquired
before routine performance. We suggest the use of fluoroscopy in difficult cases.
When US-guided PCNL is applied for patients with opaque stones, a single visualization
with fluoroscopy at the end of the procedure can be beneficial for determining the
final stone-free rate.