Percutaneous Nefrolithotomy (PCNL) with MITeC: intraoperative CT-guided evaluation of stone free rate.

Nephrolithiasis is a common disease with a prevalence of 5.5% in the general
population.The life time risk of a renal stone in the Western world is 10-15%.

Over the past decade, computed tomography (CT) has become the most common
imaging modality for renal colic, due to its diagnostic accuracy for kidney
stones with a sensitivity of 99% and specificity of 100%. Stone site and size
can be easily measured. In the latest Dutch guidelines the CT is therefore
stated as gold standard.

Large symptomatic renal calculi often need active treatment and percutaneous
nephrolithotomy (PCNL) has been accepted as highly effective treatment of these
renal calculi. Although a minimally invasive endourological technique, PCNL is
an operation with reasonable amount of complications and does not always render
the patient stone free. During the stone treatment only fluoroscopic guidance
is used. This will identify large radiopaque stones such as calcium oxalate,
and cysteine stones, but will miss radiolucent stones i.e. uric acid stones an
may miss small stones or stones overlying bony structures and the access sheet.
So, pre-operative optimal imaging is performed with a low-dose CT scan and
during PCNL surgery only suboptimal imaging is performed with ultrasonic and
fluoroscopic imaging. The stone free rate after PCNL is thereby overestimated.

Residual fragments post-PCNL give a risk of a symptomatic stone episodes and/or
the need for auxiliary treatments. Furthermore, the retreatment rates for
residual fragments <=2 mm did not significantly differ from residual fragments
larger than 2 mm, suggesting that any residual fragment may be associated with
high risk of retreatment. So, it is important to get the patient completely
stone free.

The aim of this study is to demonstrate an advantage of intraoperative
CT-guided evaluation to ensure that the patient is stone free. If there a still
fragments visible they are removed to prevent re-interventions in the future.

Explorative study of 20 patients with unilateral symptomatic nephrolithiasis
and the indication of PCNL according to the EAU/Dutch guidelines with whom PCNL
with MITeC shall be performed and will be compared to the last (consecutive) 20
patients of the historical database and literature

In the future a randomized controled trail could be performed.

By using the 5s DCT Body CARE protocol this will lead to a ERD of 5 mSv.

But when the patient is stone free routine plain radiography of the kidney
(0.1-0.3 mSv) or a non-enhanced CT-scan (4.5 mSv) on the outpatient clinic will
not be necessary. If the patient turns out to be not completely stone free on
the intraoperative CT-scan, the residual fragments can be removes in the same
session. This means that additional radiation exposure during an auxilliary
procedure will be spared.