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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3645_Библиотеки_им_академика_М_И_Перельмана
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▶ Figure23.6 shows two cryoprobes within the lesion with surrounding low density representing the ice ball
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(open arrows). e black arrow demonstrates air within the colon.
Teaching Points
▶ ermal ablation can be performed with heat (microwave/radiofrequency) or cold (cryoablation) energies.
Cryoablation allows for visualization of the iceball during the procedure.
▶ e iceball represents areas where temperatures are <0°C. To achieve satisfactory ablation margins, it should
be taken into account that lethal temperature is below–20°C, which occurs 5–6mm central to the ice ball,
depending on the probe manufacturer.
▶ Short- and long-term outcomes with both radiofrequency ablation and cryoablation show satisfactory overall
recurrence free survival when treating small renal masses.
▶ Most studies suggest that renal function is unaected by ablative treatment.
▶ When displacement of an adjacent structure is required in order to perform radiofrequency ablation, sterile
water and not saline is used, because the sodium and chloride ions in saline conduct frictional heat to
neighboring structures rather than protect them.
Management
▶ Imaging follow-up is important to promptly identify areas of incomplete ablation or local tumor recurrence
allowing for retreatment.
▶ Cryoablation of central lesions has the potential of damaging the collecting system. Some authors have
suggested insertion of a retrograde ureteral catheter to allow for warm saline infusion to protect the collecting
system during ablation.
Further Reading
Zagoria RJ, Childs DD. Update on thermal ablation of renal cell carcinoma:oncologic control, technique comparison, renal
function preservation, and new modalities. Curr Urol Rep. 2012; 13:63–69.
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History
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▶ A68-Year-Old Male with Metastatic Lung Cancer and Hip Pain
Case 24
Figure 24.1
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Case 24 Cryoablation for Pain Palliation
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Figure 24.2
Figure 24.3
Figure 24.4
Findings
▶ Alytic lesion in seen in the right iliac bone with associated cortical destruction (Fig. 24.3, black arrow).
▶ Two cryoablation probes have been placed within the target lesion with a surrounding low-density ice ball
(Fig. 24.4, white arrows) that has formed on both sides of the iliac bone.
▶ Follow-up positron emission tomography (PET)/computed tomography (CT) performed 6months aer
ablation (Fig. 24.5) demonstrates no uorodeoxyglucose (FDG) activity within the lesion (back arrow) and
mild activity in the surrounding muscle compatible with postprocedure inammation (white arrow).
Teaching Points
▶ Cryoablation is performed using specialized probes that provide alternating cycles of active cooling (by
expansion of argon gas in a xed space) and thawing (either passive or active by changing the gas in the probe
from argon to helium). is ultimately leads cell death due to rupture of the cell membrane. Typically, two
freeze-thaw cycles of 8–10 minutes are used.
▶ When considering ablation as a palliative treatment for painful bone metastases, careful examination of the
character, severity, and cause of pain should be considered.
▶ Palliative ablation for pain is indicated in patients with at least moderate pain who have failed oral analgesic
therapy and have pain localized to the target lesion.
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▶ Etiology of pain is multifactorial and includes osteoclast-mediated bone remodeling, loss of mechanical
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strength of aected bone, and activation of adjacent sensory nerve at the bone-tumor intervace.
Management
▶ Pain control is best achieved by targeting bone-tumor interface. Debulking the tumor mass is a secondary
benet of the procedure.
▶ e iceball formation can be readily monitored utilizing CT or ultrasound.
▶ During and immediately aer cryoablation for painful bone metastases, patients require less analgesia than
patients who undergo radiofrequency ablation.
Further Reading
Kurup AN, Callstrom MR. Ablation of skeletal metastases:current status. J Vasc Interv Radiol. 2010; 21:S242–S250.
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History
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▶ A13-Year-Old Girl with a 2 Month History of Le Hip Pain. What is the Best Treatment Option?
Case 25
Figure 25.1
Figure 25.2
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Case 25 Osteoid Osteoma
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Figure 25.3 Figure 25.4
Figure 25.5
Findings
▶ On computed tomography (CT), a well-dened nidus (Fig. 25.3, arrow) is seen surrounded by reactive
sclerosis (hollow arrow). e nidus is calcied in approximately 50% of patients, as seen in this case.
▶ On T1-weighted magnetic resonance (MR) (Fig. 25.4), the nidus is isointense to muscle. Peri-nidal
inammation is seen in the surrounding bone marrow.
▶ Figure 25.5 shows a Cool-tip RF Ablation electrode (Covidien, Manseld, MA) placed coaxially through the
outer cannula of a 15-gauge bone biopsy needle. Note the introducer is just through the cortex (arrow) and
approximately 2cm back from the tip of the electrode (hollow arrow).
▶ Follow-up image from a T1-weighted MR image 6 weeks aer ablation (Fig. 25.6) shows the peri-lesional
edema seen on the pretreatment MR (Fig. 25.4) has essentially resolved.
Teaching Points
▶ Osteoid osteoma is a benign tumor composed of osteoid and woven bone less than 1.5cm in diameter. ey
typically occur in juxta-articular bone in young males, most commonly the metaphysis of the femur or tibia.
▶ e classic history is focal pain, exacerbated at night, and relieved with nonsteroidal anti-inammatory agents
and exercise. Less commonly osteoid osteoma can be a cause of painful scoliosis or bone deformity.
Figure 25.6
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▶ e dierential diagnosis includes Brodie’s abscess and other rare bone tumors such as intracortical
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chondroma and osteoblastoma.
Management
▶ ermal ablation, most commonly radiofrequency ablation, is an attractive minimally invasive treatment
option for osteoid osteoma because it is done as an outpatient procedure without minimal recovery time. At
the time of the procedure, biopsy is usually performed for pathologic conrmation of the imaging diagnosis.
▶ Radiofrequency ablation of osteoid osteoma is best performed with general anesthesia when possible because
the nidus is exquisitely sensitive.
▶ Because of the straight rather than multitined design of the Cool-tip electrode, this is commonly used for
ablation of osteoid osteoma. To place the electrode, access to the nidus is achieved with a 15-gauge core biopsy
needle, which is used to perform the biopsy prior to advancing the electrode coaxially through the introducer.
It is important to ensure that the introducer of the cannula is retracted to at least 1–2cm back from the tip of
the electrode to prevent inadvertent heating of the introducer.
▶ With the Cool-tip electrode, ablation is performed on cautery (not ablation) mode for 6 minutes.
Further Reading
Motamedi D, Learch TJ, Ishimitsu DN, etal. ermal ablation of osteoid osteoma:overview and step-by-step guide.
Radiographics. 2009; 29(7):2127–2141.
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Case 26
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History
▶ A67-Year-Old Male with Lung Cancer and a Single, Biopsy-Proven, Adrenal Metastasis
Secondary to cardiopulmonary compromise, he was deemed a poor surgical candidate. e following images
illustrate the treatment. However, in the middle of the treatment the patient’s blood pressure acutely increases to
200/120 from a baseline of 125/65.
Figure 26.1
Figure 26.2
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Case 26 Hypertensive Crisis during Adrenal Radiofrequency Ablation
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Figure 26.3
Figure 26.4
Figure 26.5
Findings
▶ Initial computed tomography (CT) through the level of the adrenal gland demonstrates a nodule (arrow)
representing the biopsy-proven adrenal metastasis (Fig. 26.3). Intraprocedural image (Fig. 26.4) demonstrates
the ablation probe within the lesion.
▶ Follow-up imaging 29months aer ablation (Fig. 26.5) demonstrates interval decreased size and fullness of
the ablated lesion (arrow).
Teaching Points
▶ In nonsurgical candidates, thermal ablation represents a reasonable alternative to treatment of both primary
and metastatic adrenal lesions.
▶ During adrenal ablation, acute hypertension is most likely related to systemic catecholamine release by the
ablated adrenal tissue.
▶ Because of the concern for catecholamine release during adrenal ablation, some advocate pretreatment with
alpha blockade. Oral phenoxybenzamine has been used as pretreatment days to weeks prior to ablation.
▶ Ablation should be performed with constant monitoring of vital signs, especially blood pressure. Hypertensive
crisis should be promptly treated by shutting o ablation energy and use of intravenous antihypertensive
medication.
■ For RFA and microwave energy, ablation should be shut o.
■ For cryoablation, hypertensive crisis tends to occur during active thaw; rapid refreeze is a potential
immediate treatment.
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Management
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▶ Short-interval oce visit aer ablation should focus on identication of resolution of clinical syndromes and
biochemical markers (for primary adrenal tumors). Antihypertensives should also be adjusted at this time.
▶ Short-interval CT or magnetic resonance imaging (MRI) for a new baseline is performed 1–3months aer
ablation and patients are followed with repeat CT or MRI every 3months to evaluate for local recurrence.
Further Reading
Pua BB, Solomon SB. Ablative therapies for adrenal tumors. J Surg Oncol. 2012; 106:626–631.
Venkatesan AM, Locklin J, Dupuy DE, etal. Percutaneous ablation of adrenal tumors. Tech Vasc Interv Radiol. 2010; 13:89–99.
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