Добавил:

Sekretar kiopkiopkiop18@yandex.ru t.me/Prokururor I Вовсе не секретарь, но почту проверяю Опубликованный материал нарушает ваши авторские права? Сообщите нам.

Вуз:

Ростовский Государственный Медицинский Университет

Предмет:

Медицина общая

Файл:

Книга_3892_Библиотеки_им_академика_М_И_Перельмана

.pdf

Скачиваний:

Добавлен:

10.10.2026

Размер:

9 Мб

Скачать

☆

<<< < Предыдущая 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 4647 / 5047 48 49 50 > Следующая >>>

468

What are some

alternative invasive

treatment options for

renal malignancies?

Radical nephrectomy and nephron-

sparing surgery (NSS) either open or

laparoscopic. These options are more

ideal for larger, more centrally located

RCCs. NSS is preferred over radical

nephrectomy for localized RCC.

Is there a size threshold

for renal tumor thermal

ablation?

Yes, renal tumors <4cm in size

typically respond better to thermal

ablation. In fact, best results have

been reported for tumors <3cm in

size and exophytic inlocation.

What are some

indications for tumor

ablation treatment of

renal malignancies?

Poor surgical candidates, advanced

age, solitary kidney, familial

syndromes, and multiple comorbid

conditions

What are the absolute

contraindications to

thermal ablation?

Uncorrectable coagulopathy with

INR >1.5 and platelets <50,000 per

microliter

What are some relative

contraindications for

tumor ablation?

Anteromedially/centrally located

tumors with no safe route, hip

prosthesis, and pacemaker/

defibrillator. Large tumor size and

inability to separate tumor from

nearby vital structures, such as the

bowel or ureter, should also be

considered.

When can renal

artery embolization

be considered for

treatment?

Prior to nephrectomy, for palliation,

in preparation for ablation, and for

the treatment of AMLs (>4cm).

Indications for palliation in the setting

of advanced stage RCC include

hematuria, flank pain, and control of

paraneoplastic syndromes.

What are some

contraindications to renal

artery embolization?

Although there is no absolute

contraindication, relative

contraindications include contrast

allergy, renal insufficiency, pregnancy,

infection, and solitary kidney.

S. Khan and M. J. Uceda

https://t.me/med1917

469

Relevant Anatomy

What is the basic

renal anatomy?

The kidney has an outer cortex and inner

medulla. The renal hilum located medially

is where the renal vessels, nerves, and

ureter pass. The kidneys, renal vessels,

proximal collecting systems, adrenal

glands, and some fat are located within the

perirenal space (a retroperitoneal space),

which is bound by perirenal fascia. The

two other retroperitoneal spaces are the

anterior and posterior pararenal spaces.

What are some

anatomic structures

to keep in mind

when performing an

ablation?

Vascular pedicle and any neighboring

bowel and ureter. Also, it is best to avoid

traversing through the lung pleura, as this

can lead to a pneumothorax.

What are common

anatomic variants

that may be

encountered

during renal artery

embolization?

Variants include accessory renal arteries

and early division of the renal arteries.

Being aware of these will help ensure as

complete as possible of an embolization

and procedure success.

Are there any

other special

considerations

and/or techniques

one can use when

performing tumor

ablation for RCC?

Hydrodissection is useful to separate

the structures when there is not enough

margin in between the ureter/bowel and

the tumor.

As mentioned above, pre-ablation

embolization may reduce the risk of

hemorrhage and has the benefit of less

heat sink.

What else can be

done to protect

the ureter during

thermal ablation?

A retrograde ureteral stent can be

placed with infusion of fluid through the

collecting system.

Renal Oncology

https://t.me/med1917

470

Relevant Materials

What are the

different kinds

of ablation

techniques

currently

available?

Radiofrequency ablation (RFA), microwave,

laser, and cryoablation. A newer procedure

called irreversible electroporation (IRE) uses

electric currents to increase permeability of

the cell membranes. This disrupts cellular

hemostasis and induces cell death via

apoptosis or other internally induced necrotic

pathways.

What different

arrays are

available

for thermal

ablation?

Both linear and multi-tined or umbrella-

shaped array devices may be used depending

on the shape and size of the tumor. Straight/

linear electrodes may require multiple

insertions.

What are

some common

embolization

materials that

are used?

Coils, gelfoam, polyvinyl alcohol (PVA), and

Embospheres. Chemoembolization with drug-

eluting embolic (DEE) agent saturated with

doxorubicin has also been shown to help in

palliation of RCC.There may also be potential

for use of radioembolization with Yttrium-90

(Y-90) resin microspheres.

How does RFA

work?

Briefly, the RF electrode itself is not the

source of heat. Rather, the RF electrode

generates an alternating electromagnetic field

which agitates local molecules, resulting in

the production of heat. The high temperatures

results in coagulative necrosis of adjacent

tissue.

How does

microwave

ablation (MWA)

differ from

RFA?

MWA uses an oscillating microwave

electromagnetic field to increase kinetic

energy and produce heat. MWA produces heat

faster, has a more predictable ablation zone,

and is not as affected by heat sink.

S. Khan and M. J. Uceda

https://t.me/med1917

471

How does

cryoablation

work?

When compressed gas, typically argon, is

forced through the narrow opening of a

cryoprobe, the rapid expansion of the gas

results in a decrease in the temperature of

the gas (Joule-Thomson effect). Cryoablation

results in cell death by direct (cold-induced

cellular injury) and indirect (changes to the

cellular microenvironment and impairment of

tissue viability) effects.

General Step by Step

What is the ideal

patient positioning

for ablation?

Prone in most cases and supine if the

target is a transplanted kidney. Consider

angling of the gantry in the prone position

to aid in determining ideal needle

trajectory. Oblique supine positioning

can be used for laterally located lesions

and also to displace the bowel medially.

Ipsilateral decubitus positioning is

useful for lower pole masses and aids in

displacing the lung, as well as reducing

target (ipsilateral) kidney motility.

What are some pre-

procedure steps that

should be taken?

Consultation including history, pre-

procedure imaging, possible pre-

procedure biopsy, overnight fast, and

prophylactic antibiotics. A biopsy can also

be performed at the same time as the

ablation if necessary.

How is

hydrodissection

performed?

After achieving local anesthesia, a small

needle can be introduced between the

tumor and adjacent vital structure.

Following this, saline can be injected and

infused continuously during the procedure

to help separate the tumor from the

adjacent vital structure.

(continued)

Renal Oncology

https://t.me/med1917

472

How is

pyeloperfusion

performed?

A retrogradely placed ureteral stent is

connected to a bag of a slow drip infusion

of 1–2 drops/second.

What is the ablation

technique utilized

for cryoablation?

After advancing the ablation probe

into the mass under imaging guidance,

cryoablation can be performed with

freeze-thaw cycles, such as a 10-minute

freeze cycle followed by an 8-minute

thaw cycle, followed by an additional

freeze cycle. Temperatures < −40°C are

necessary to ensure tumoral cell death.

What is the ablation

technique for RFA

and MWA?

After advancing the ablation probe into

the mass under imaging guidance, the mass

is ablated for approximately 10minutes

for RFA and a few minutes for MWA.

Why is it also

important to ablate

the entry tract during

tumor ablation?

This limits the possibility of a calyceal-

cutaneous fistula and tumor seeding.

Ablation should be stopped within 1cm

of the skin surface to prevent skin burns.

Tract ablation is performed with heat-

based ablation.

What must be done

following ablation?

Post-ablation multiphase CT scan must be

performed to demonstrate lack of vascular

or collecting system injury.

How can the renal

artery be selected

for renal artery

embolization?

After acquiring arterial access, 5-Fr

selective catheters, such as a Sos, Cobra,

or Simmons catheters, can be used to

gain access into the renal artery. For

small tumors, selective catheterization

with microcatheters can also be achieved.

Accurate selection reduces the chance of

nontarget embolization and minimizes

non-tumoral nephron death.

What embolic

material should be

used for renal artery

embolization?

The choice of embolic material depends

on the operator’s experience and

preference. Post-embolization angiography

must be performed to demonstrate degree

of desired vessel occlusion.

S. Khan and M. J. Uceda

https://t.me/med1917

473

Complications

What are some

side effects

of radical

nephrectomy?

Nephrectomy can increase the risk of

chronic kidney disease, particularly if the

patient is already diabetic. It also has a

longer recovery period and is associated

with increased morbidity and mortality

compared to the other less invasive

techniques. Complications include infection,

bleeding, and even death.

What are some

potential adverse

effects of tumor

ablation?

Hemorrhage, infection, ureteric stricture,

bowel injury, nerve injury, adrenal crisis

(consider premedication with alpha-

and beta-blockers for a week), and

pneumothorax

What are potential

adverse effects

of renal artery

embolization?

Post-embolization syndrome consisting of

fatigue, pain, fever, nausea, and vomiting.

Other less likely complications include

infection and nontarget embolization.

What are the

benefits of

performing

renal artery

embolization prior

to nephrectomy?

Decreased perioperative bleeding, creation

of a tissue plane which can ease in dissection

of the kidney, and reduction in tumor

bulk and possibly reduction in vascular

thrombosis

What can be done

to minimize the

effects of post-

embolization

syndrome (PES)

after renal artery

embolization?

PES can be controlled symptomatically with

pre- and post-medication, which includes

steroids, pain control, antiemetics, and

hydration.

(continued)

Renal Oncology

https://t.me/med1917

474

If embolization was performed for

nephrectomy planning, performing the

nephrectomy within 48hours of the renal

artery embolization can reduce the effects of

post-embolization syndrome. If nephrectomy

is performed >72hours post-embolization,

the surgery can potentially become

technically difficult related to collateral

vessel formation.

Landmark Research

Clark W, Aslan P, Patel M, Vass J, Cade D, de Silva S, etal. The

RESIRT study: feasibility and dosimetry considerations of

selective internal radiation therapy (SIRT) using yttrium-90

(Y-90) resin microspheres in patients with primary renal cell

carcinoma (RCC). J Vasc Interv Radiol. 2017;28(2 Suppl):S164.

• SIRT with Y-90 microspheres was technically feasible in

patients with RCC.Tumors should be treated to imminent

stasis.

Hui GC, Tuncali K, Tatli S, Morrison PR, Silverman

SG.Comparison of percutaneous and surgical approaches to

renal tumor ablation: metaanalysis of effectiveness and com-

plication rates. J Vasc Interv Radiol 2008; 19:1311–1320.

• A percutaneous approach was found to be safer and just as

effective in treating RCC compared to an open or laparo-

scopic, although multiple treatments may be needed.

Jasinski M, Siekiera J, Chlosta P, et al. Radiofrequency

ablation of small renal masses as an alternative to nephron-

sparing surgery: preliminary results. Videosurgery Miniinv.

2011;6:242–5.

• RFA can be safely used in treating T1a tumors as an alter-

native to partial nephrectomy. Careful follow-up is needed

to look for tumor recurrence.

S. Khan and M. J. Uceda

https://t.me/med1917

475

Karalli A, Ghaffarpour R, Axelsson R, Lundell L, Bozoki

B, Brismar T, etal. Transarterial chemoembolization of renal

cell carcinoma: a prospective controlled trial. J Vasc Interv

Radiol. 2017;28(12):1664–72.

• Drug-eluting embolization (DEE) is a safe way to treat

localized RCC and has a superior cytoreductive effect

compared to transarterial embolization (TAE).

Kunkle DA, Uzzo RG. Cryoablation or radiofrequency

ablation of the small renal mass: a meta-analysis. Cancer

2008;113: 2671–1280.

• Data suggested that cryoablation may require fewer re-

treatments with improved local control and decreased risk

of metastatic progression compared to RFA.

Wagstaff P, Ingels A, Zondervan P, etal. Thermal ablation

in renal cell carcinoma management: a comprehensive review.

Curr Opin Urol. 2014;24:474–82.

• Thermal ablation is a safe way to treat small renal masses;

however, there is a small risk of residual disease.

Yin X, Cui L, Li F, etal. Radiofrequency ablation versus

partial nephrectomy in treating small renal tumors: a system-

atic review and meta-analysis. Medicine (Baltimore)

2015;94:e2255.

• RFA has a similar oncologic benefit compared to partial

nephrectomy with similar complications rates in treatment

of small renal tumors. There is a lower decline in eGFR

and a shorter length of stay (LOS) with RFA.

Zielinski H, Szmigielski S, Petrovich Z. Comparison of

preoperative embolization followed by radical nephrectomy

with radical nephrectomy alone for renal cell carcinoma. Am

J Clin Oncol. 2000;23(1):6–12.

• Preoperative renal artery embolization (PRAE) is a safe

technique in management of large and advanced

RCC. There was decreased median blood loss in the

PRAE group compared to the no-PRAE group (250mL

versus 400mL).

35 Renal Oncology

https://t.me/med1917

476

Common Questions

What is the heat

sink effect?

Perfusion-mediated cooling by adjacent vessels

which limit the size of the ablation zone. This

is more of a technical challenge in RFA when

compared to microwave ablation. The heat sink

effect does not exist in IRE technique.

What is the

typical follow-up

after ablation?

A follow-up CT/MR with contrast can be

performed in 1–3months post-ablation and

then annually. There may be some post-

procedural enhancement related to hyperemia;

however, an increase in the degree of

enhancement as well as any asymmetric and/or

nodular enhancement involving the margins of

the ablation zone on subsequent scans would

be suspicious for tumor recurrence/progression.

What is the ideal

ablation margin?

A 0.5–1-cm margin is ideal. If the margin

between the ablation zone and a vital

neighboring structure is <1cm, hydrodissection

or pneumodissection can be used.

How does

tumor ablation

compare to the

gold standard of

radical or partial

nephrectomy?

The 5-year recurrence-free survival rate of

partial nephrectomy has been reported to be

greater than 97% and that of thermal ablation

to range from 87% to 97%.

How does

the cost of

thermal ablation

compare to

nephrectomy?

Early 6-month cost comparisons show thermal

ablation to be cheaper than nephrectomy. As

outcomes become comparable with time, cost

comparison may begin to play a larger factor in

decision-making.

How do

cryoablation and

RFA or MWA

compare in

performance?

Results comparing cryoablation and RFA or

MWA do not vary greatly, and larger studies

and trials are necessary to detect differences

between the two. Therefore, the choice

between them depends mostly on operator

experience and preference. There is a higher

bleeding risk with cryoablation compared to

RFA (4.8% versus 1.2%).

S. Khan and M. J. Uceda

https://t.me/med1917

477