AJR 2005; 185:86-88
© American Roentgen Ray Society
Percutaneous Transthoracic Radiofrequency Ablation of Renal Tumors Using an Iatrogenic Pneumothorax
Kamran Ahrar1,
Surena Matin2,
Michael J. Wallace1,
Sanjay Gupta1 and
Marshall E. Hicks1
1 Interventional Radiology, The University of Texas M. D. Anderson Cancer
Center, 1515 Holcombe Blvd., Box 325, Houston, TX 77030.
2 Urology, The University of Texas M. D. Anderson Cancer Center, Houston, TX
77030.
Received August 30, 2004;
accepted after revision October 8, 2004.
Address correspondence to K. Ahrar
(kahrar{at}mdanderson.org).
Abstract
OBJECTIVE. We report on a new technique for percutaneous
radiofrequency ablation of tumors in the upper pole of kidneys in the presence
of intervening lung parenchyma.
CONCLUSION. Percutaneous radiofrequency ablation of tumors in the
upper pole of kidneys with intervening lung parenchyma can be accomplished
successfully using a transthoracic approach through an iatrogenic
pneumothorax. This technique allows for precise placement and repositioning of
the radiofrequency electrode under CT guidance without repeated puncture of
the visceral pleura.
Introduction
Percutaneous radiofrequency ablation of renal tumors is a minimally
invasive treatment appropriate for certain patients with renal cell carcinoma:
those at high surgical risk, those with a solitary kidney not amenable to
nephron-sparing surgery, and those with multifocal renal cell carcinoma
[1-4].
Some investigators have suggested that tumors in the upper pole of the kidneys
cannot be safely treated by percutaneous radiofrequency ablation because of
intervening lung parenchyma
[5]. We describe a technique
that we have used successfully for radiofrequency ablation of upper pole renal
tumors in the presence of intervening lung tissue. This technique involves
transthoracic placement of the radiofrequency electrode through an iatrogenic
pneumothorax using CT.
Materials and Methods
Our institutional review board reviewed and approved this study. A waiver
of informed consent and a waiver of authorization to use and disclose
protected health information were granted.
We retrospectively reviewed the records of 29 patients with renal cell
carcinoma who were treated at our institution with percutaneous radiofrequency
ablation from September 2001 to March 2004. We identified four patients who
had tumors involving the upper pole of the kidney. There were three men and
one woman with a mean age of 74 years (range, 69-83 years). Indications for
radiofrequency ablation included one or more of the following: high surgical
risk (n = 2), concurrent treatment for other malignancies (n
= 3), or a solitary kidney (n = 1). The mean tumor size was 3.5 cm in
the largest diameter (range, 2.5-5.3 cm). In all four patients, the tumor was
located in the right kidney (Figs.
1A,
1B,
1C, and
1D).
View larger version (126K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1A —83-year-old man with renal cell carcinoma of right kidney.
Axial, contrast-enhanced CT image of abdomen in supine position shows 3.4-cm
solid enhancing mass in upper pole of right kidney.
|
|
After induction of general anesthesia, each patient was placed in the prone
position on the CT scanner (GE Healthcare). Axial CT images demonstrated
intervening lung parenchyma in all four patients. An intentional pneumothorax
was created using a 20-gauge Chiba needle (Cook). The needle was advanced in
an axial plane toward the target tumor with the intention of injecting air
into the pleural cavity. Positioning the needle into the pleural cavity
resulted in pneumothorax in all four cases and manual injection of air was not
required in any of the four cases. All patients were treated with a cluster
electrode from Radionics. The radiofrequency ablation electrode was placed in
a transpleural but extrapulmonary fashion into the upper pole tumor. An
average of three ablations per patient was performed (range, 2-4 ablations)
for a total of 12 overlapping ablations.
All radiofrequency ablation procedures were technically successful without
any complications related to pneumothorax. All four patients were easily
ventilated during the procedure. At the end of the procedure, a moderate
pneumothorax was identified in three patients. In these patients, an
8.5-French pneumothorax evacuation tube (Cook) was placed under CT guidance.
Tubes were placed by standard Seldinger technique from a posterior approach
without repositioning the patients. Each tube was connected to a Heimlich
Chest Drain Valve (Cook). The pneumothorax in the fourth patient was small and
did not require treatment. All four patients were successfully extubated after
the procedure. Expiratory chest radiograms were obtained in all patients the
next morning at a mean interval of 18 hr (range, 17-19 hr). In three patients
with chest tubes, the lungs were fully expanded. The chest tubes were clamped
for 2 hr, and a repeat chest radiogram showed no recurrent pneumothorax. All
tubes were successfully removed, and patients were discharged home in stable
condition without any further sequelae. The fourth patient with a small
pneumothorax that was not treated was found to have a small, stable
pneumothorax on the follow-up examination but required no further treatment.
Follow-up imaging at a mean of 2.5 months (range, 1-4 months) showed no
recurrent pneumothorax or pleural effusion in any of the patients.
Discussion
Percutaneous radiofrequency ablation is a minimally invasive therapy for
management of certain patients with renal cell carcinoma
[1-4].
Although sonography can be used for targeting of smaller tumors for
radiofrequency ablation [4], CT
appears to be the technique of choice
[1-3].
CT-guided radiofrequency ablation of renal tumors often is performed with the
patient in the prone position. However, access to the upper pole tumors may be
limited as a result of intervening lung parenchyma. Some investigators have
incorporated imaging of the patient in a prone position into their diagnostic
CT protocols and have excluded patients in whom the lung base extends over the
target tumor in the upper pole of the kidney
[5].
To avoid puncturing the lung with the radiofrequency electrode, one can
start the puncture site inferior in relation to the tumor and pleural
reflection and triangulate the placement of the electrode into an upper pole
tumor. One also can angulate the CT gantry to monitor the path of the needle.
Both of these techniques are used for biopsy of abdominal and retroperitoneal
masses [6,
7]. While triangulation is
effective for performing biopsies, it may not be optimal for radiofrequency
ablation of renal tumors. Treatment of larger renal tumors with radiofrequency
ablation requires precise positioning of the electrode and creation of
multiple overlapping ablations so that the whole tumor is treated. Currently,
there are no computer software programs to facilitate this task, and the whole
analysis takes place in the mind of the operator. When triangulation
techniques or angling of the gantry is used, it becomes increasingly difficult
to picture the tumor and the overlapping ablations three-dimensionally,
resulting in unnecessary overablation in some areas and underablation in other
areas of the tumor.
In our technique, we circumvented these problems by a transthoracic
approach to the kidney. In this case, an intentional pneumothorax is created,
as has been described in the literature for the biopsy of mediastinal masses
[8]. With the lung retracted
from the base of the pleural cavity, a clear path becomes available for
placement of the electrode in a nearly axial plane. In this fashion, a
treatment plan, consisting of the number and location of overlapping
ablations, can be formulated in the mind of the operator. The electrode can be
retracted and repositioned without puncturing the visceral pleura, minimizing
the risk of prolonged air leak or formation of bronchopleural fistulas. When
the ablation is completed, one can use an 18-gauge needle or a small catheter
to evacuate the pneumothorax. Alternatively, a small (8.5-French) pneumothorax
evacuation tube can be inserted posteriorly in the base of the pleural cavity
without repositioning the patient. The tube can be connected to suction or a
Heimlich Chest Drain Valve. Patients even can be discharged with the chest
tube connected to the Heimlich valve. The patient then returns in
approximately 24 hr for evaluation of the pneumothorax and chest tube removal.
In our patients, initial needle placement could have resulted in the puncture
of the visceral pleura. Furthermore, we performed all radiofrequency ablations
with the patient under general anesthesia and admitted all of our patients for
overnight observation. For these reasons, we chose to treat our patients with
pneumothorax evacuation tubes rather than simple evacuation of the
pneumothorax using a needle.
Although we did not encounter a tension pneumothorax in any of our
patients, it is a potentially life-threatening complication resulting from
this technique. One must be cognizant of the size of the pneumothorax and
early signs of developing tension pneumothorax. A rapidly enlarging
pneumothorax or a tension pneumothorax can be readily treated with placement
of a chest tube under CT guidance. Another potential complication is seeding
of the tract with neoplastic cells. Of the 213 treated tumors reported in the
literature, only one case of seeding has been encountered (0.47%). This risk,
albeit small, is present regardless of whether a transpleural or
retroperitoneal approach is selected. Early detection and prompt treatment
remain the only viable options to manage this potential complication.
In our experience, the intentional pneumothorax can be treated easily, and
the chest tubes can be removed successfully fewer than 24 hr following the
procedure. We have not encountered any other adverse sequelae from puncturing
the parietal pleura or the diaphragm with the radiofrequency ablation
electrodes.
In conclusion, we have found that CT-guided, transthoracic radiofrequency
ablation of tumors in the upper pole of the kidneys through an intentionally
created pneumothorax is feasible and allows for the percutaneous treatment of
patients who may be at high surgical risk.
References
- Gervais DA, McGovern FJ, Arellano RS, McDougal WS, Mueller PR.
Renal cell carcinoma: clinical experience and technical success with
radio-frequency ablation of 42 tumors. Radiology2003; 226:417
-424[Abstract/Free Full Text]
- Mayo-Smith WW, Dupuy DE, Parikh PM, Pezzullo JA, Cronan JJ.
Imaging-guided percutaneous radiofrequency ablation of solid renal masses:
techniques and outcomes of 38 treatment sessions in 32 consecutive patients.
AJR 2003;180:1503
-1508[Abstract/Free Full Text]
- Su LM, Jarrett TW, Chan DY, Kavoussi LR, Solomon SB. Percutaneous
computed tomography-guided radiofrequency ablation of renal masses in high
surgical risk patients: preliminary results. Urology2003; 61:26
-33[CrossRef][Medline]
- Farrell MA, Charboneau WJ, DiMarco DS, et al. Imaging-guided
radiofrequency ablation of solid renal tumors. AJR2003; 180:1509
-1513[Abstract/Free Full Text]
- Ogan K, Jacomides L, Dolmatch BL, et al. Percutaneous
radiofrequency ablation of renal tumors: technique, limitations, and
morbidity. Urology2002; 60:954
-958[CrossRef][Medline]
- Yueh N, Halvorsen RA Jr, Letourneau JG, Crass JR. Gantry tilt
technique for CT-guided biopsy and drainage. J Comput Assist
Tomogr 1989;13:182
-184[Medline]
- Hussain S. Gantry angulation in CT-guided percutaneous adrenal
biopsy. AJR1996; 166:537
-539[Abstract/Free Full Text]
- Zwischenberger JB, Savage C, Alpard SK, Anderson CM, Marroquin S,
Goodacre BW. Mediastinal transthoracic needle and core lymph node biopsy:
should it replace mediastinoscopy? Chest2002; 121:1165
-1170[Abstract/Free Full Text]
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
Top
Abstract
Introduction
