AJR 2000; 174:1595-1596
© American Roentgen Ray Society
Sonographic Guidance of Laparoscopic Renal Cryoablation
Erick M. Remer1,
Jonathan C. Hale1,
Charles M. O'Malley1,
Karen Godec1 and
Inderbir S. Gill2
1
Division of Radiology, The Cleveland Clinic Foundation, 9500 Euclid Ave.,
Cleveland, OH 44195.
2
Section of Minimally Invasive Surgery, Department of Urology, The Cleveland
Clinic Foundation, Cleveland, OH 44195.
Received August 9, 1999;
accepted after revision October 25, 1999.
Address correspondence to E. M. Remer.
Introduction
For patients with small (<4 cm) renal cell carcinomas, open partial
nephrectomy offers comparable survival rates and preserves more renal function
than radical nephrectomy [1].
Because an increasing number of renal tumors are discovered incidentally
[2], an even less invasive
nephron-sparing alternative treatment would be attractive to patients and
urologists. With the development of supercooled minimally invasive
cryodelivery systems and the availability of reliable real-time sonographic
monitoring, it is technically possible to perform successful laparoscopic
cryoablation. Currently, laparoscopic renal cryoablation is being investigated
as a minimally invasive alternative to open partial nephrectomy for the
treatment of patients with small (<4 cm) unilateral localized renal cell
carcinomas [3].
Previous reports have described sonographically guided open hepatic
cryoablation [4]. Although
researchers have not directly addressed the sonographic technique, a few cases
of laparoscopic hepatic cryoablation have been reported
[5]. One report describes
sonographically guided renal cryoablation during open laparotomy
[6]. We describe
sonographically guided laparoscopic renal cryoablation, sonographic findings,
and differences between laparotomy and laparoscopy.
Subjects and Methods
After informed consent, 25 patients (15 men and 10 women; age range, 36-84
years; mean age, 67 years; SD, 11.7) underwent sonographically guided renal
cryoablation. Twenty-six renal masses were cryoablated: 12 were right-sided
and 14 were left-sided. On preoperative CT, the average tumor size was 2.0 cm
(SD = 0.5) and each tumor was suggestive of malignancy based on standard
criteria. All lesions were located in the peripheral kidney. Indications for
cryoablation included a small (
4 cm) mass (n = 10) with
contralateral renal impairment including solitary kidney (n = 7),
prior contralateral renal cell carcinoma (n = 4), renal dysfunction
(n = 2), or severe calculus disease (n = 1). One patient
underwent cryoablation for suspected renal metastases.
Retroperitoneal or transperitoneal laparoscopic access was performed
depending on mass location inside the kidney. After laparoscopic ports were
placed, perinephric fat removed, and the kidney mobilized within Gerota's
fascia, the radiologist was called to the operating room. A steerable
multifrequency laparoscopic convex array sonographic probe (Model 8555; B
& K, Genthoften, Germany) was placed through a laparoscopic port. The
renal mass was identified and sonography and direct laparoscopic guidance were
used to perform a 16-gauge core biopsy.
Ideally the laparoscopic probe was positioned on the renal surface opposite
the tumor (Fig. 1). Alternative
positioning was used if the tumor position required it, most often for
exophytic lesions in the upper or lower pole. For these masses, we placed the
probe on a renal surface so that an adequate acoustic window could be
obtained. Sonographic guidance was used to position a 4.8-mm conic tip
cryoprobe to the deepest margin of the renal lesion. Cryoablation was
performed with a liquid nitrogen-based cryosystem (Accuprobe 450; Cryomedical
Sciences, Rockville, MD). Similar to sonographic appearances described in
other reports, in our study, the growing iceball appeared as an enlarging
hyper-echogenic curvilinear surface with posterior acoustic shadowing
[4,5,6]
(Fig.
2A,2B,2C).
Sonography was used to monitor iceball size. Previous studies determined that
sound cannot penetrate an iceball; therefore, if a lesion is still visible,
then it has not been adequately treated
[4,
6]. We continued freezing until
the renal mass was completely engulfed and a 1-cm margin of normal renal
parenchyma was frozen. The relationship of the iceball to the renal sinus was
followed so that collecting system involvement was avoided. A second freeze
cycle was then performed to ensure complete tumor destruction. Unless complete
thawing occurred, sonographic findings persisted. Because a complete thaw did
not routinely occur because of time constraints (thaw time > 20 min), the
remaining iceball often obscured portions of the mass. During the second
freeze cycle, cryoablation was monitored by initial freezing time. If freezing
extended beyond the confines of the original iceball, then additional
increasing size was noted. The laparoscopic probe was frequently rotated or
translated along the renal surface to change the position of the insonating
beam or ensure the complete visibility of the growing iceball and the tumor,
respectively. Follow-up MR imaging performed 1 day after treatment revealed
findings suggestive of untreated tumor. Subsequent MR imaging was performed at
1, 3, 6, and 12 months to assess tumor recurrence.
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Fig. 1. —Drawing shows laparoscopic sonography probe on anterior surface of
kidney opposite posterior renal tumor. Conically tipped cryoprobe is inside
renal mass. Iceball covers small portion of mass. Shaded cone emanating from
renal mass represents shadowing seen on sonographic images. (Reprinted with
permission from the Cleveland Clinic Foundation)
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Fig. 2A. —48-year-old man with 2-cm renal cell carcinoma. Early transverse
laparoscopic sonogram with probe positioned on renal anterior surface opposite
tumor shows curvilinear hyperechogenic interface with posterior acoustical
shadowing. Small ovoid hypoechogenic area corresponds to cystic portion of
tumor not yet treated (curved arrow). Linear echo represents
cryoprobe (straight arrow).
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Fig. 2C. —48-year-old man with 2-cm renal cell carcinoma. Coronal T1-weighted
breath-hold gadopentetate dimeglumine-enhanced MR image (TR/TE, 142/4.4; flip
angle, 80°) shows unenhanced cryolesion. Note thin rim of peripheral
enhancement (arrow).
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Discussion
Cryotherapy has been used as a minimally invasive treatment for
malignancies of the liver and prostate, and more rarely, the brain, bones,
pancreas, and uterus [7]. The
details of sonographic guidance during open procedures, especially for the
liver, have been previously described
[4]. The application of this
therapy to laparoscopy and the treatment of renal malignancies provides an
opportunity to further develop the technique of cryotherapy.
Small laparoscopic sonographic transducers require less space and are
easier to position than probes used during open procedures. One disadvantage
of these probes is the somewhat limiting nature of a fixed laparoscopic port
through which the sonoprobe must be introduced.
Performing cryotherapy in the kidney is easier than in the liver for
several reasons. Because the kidney is smaller than the liver and relatively
mobile once mobilized surgically, the sonographic probe can be moved to
multiple imaging positions. Varying the probe position was important to ensure
complete tumor destruction. By scanning from the renal surface opposite the
tumor, the deepest margin of the tumor was insonated first, allowing the
visualization of its enlarging margin. This arrangement prevented shadowing of
the growing iceball (Fig. 1).
Because the deepest margin of the mass is most at risk for incomplete freezing
[4], the probe positioning we
used was ideal. Positioning the sonographic probe on the surface opposite the
cryoprobe provides two additional benefits: a larger distance between the two
probes and avoidance of thermal damage to the transducer elements.
Researchers have described the need to image the cryoprobe in orthogonal
planes to avoid eccentric placement within a mass during open hepatic
cryotherapy [4]. This imaging
can be performed by altering the probe position or by using a biplane
transducer. In the laparoscopic environment, imaging becomes more difficult.
The fixed site of the laparoscopic port and the inability to flex the
transducer on the probe shaft in more than one plane prevents imaging in two
orthogonal planes for many patients. However, in our study, incompletely
treated renal lesions were not seen on postoperative MR images, probably
because of the peripheral location and small size of the treated lesions. Most
patients had a short distance of normal parenchyma through which to guide the
cryoprobe, making placement of the probe in the center of the mass easier.
Further, direct laparascopic visualization was used to assess the superficial
portion of the iceball, and sonography was used to assess the advancing margin
of the mass.
Our approach differs from that of Feld et al.
[8] in many ways. Feld et al.
described the use of an end-fire intracavitary probe to guide renal
cryoablation. We agree that standard laparoscopic sonographic probes are
difficult to use to guide the biopsy of renal masses. The geometry of using
different access ports for the biopsy needle and sonographic probe can be
vexing. Unlike the Feld et al. report, all the masses treated in our study
were peripheral in location; therefore, laparoscopic visualization was used to
guide the biopsy needle. We favor direct puncture cryoablation rather than a
coaxially guided technique [8].
Therefore, we did not have to place a needle and guidewire during
cryoablation; instead, we used sonography alone to guide the cryoprobe.
In summary, other researchers have revealed the value of sonography in
guiding open cryotherapy. We discussed the technique of sonographically guided
laparoscopy and how it can be used to successfully perform renal
cryoablation.
References
-
Butler BP, Novick AC, Miller DP, Campbell SA, Licht MR. Management
of small unilateral renal cell carcinomas: radical versus nephron-sparing
surgery. Urology
1995;45:34
-40[Medline]
-
Smith SJ, Bosniak MA, Megibow AJ, et al. Renal cell carcinoma:
earlier discovery and increased detection. Radiology
1989;170:699
-703[Abstract/Free Full Text]
-
Gill IS, Novick AC, Soble JJ, et al. Laparascopic renal
cryoablation: initial clinical series. Urology
1998;52:543
-551[Medline]
-
Lee FT Jr, Mahvi DM, Chosy SG, et al. Hepatic cryosurgery with
intraoperative US guidance. Radiology
1997;202:624
-632[Free Full Text]
-
Iannitti DA, Heniford T, Hale J, Grundfest-Broniatowski S, Gagner
M. Laparoscopic cryoablation of hepatic metastases. Arch
Surg 1998;133:1011
-1015[Abstract/Free Full Text]
-
Zegel HG, Holland GA, Jennings SB, Chong WK, Cohen JK.
Intraoperative ultrasonographically guided cryoablation of renal masses:
initial experience. J Ultrasound Med
1998;17:571
-576[Abstract]
-
Baust J, Gage AA, Ma H, Zhang CM. Minimally invasive cryosurgery:
technological advances. Cryobiology
1997;34:373
-384[Medline]
-
Feld RI, McGinnis DE, Needleman L, Segal SR, Strup SE, Nazarian LN.
A novel application for the end-fire sonographic probe: guidance during
cryoablation of renal masses. AJR
1999;173:652
-654[Free Full Text]
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Introduction
Subjects and Methods
