Key words
guideline - ultrasound guidance - abscess - hepatocellular carcinoma - liver metastases
- radiofrequency ablation - drainage - safety
Introduction
This is the third of three guidelines (parts I – III) within the framework of the
European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Guidelines
on Interventional Ultrasound describing ultrasound (US)-guided percutaneous diagnostic
and therapeutic interventions of the abdomen. Part III deals with the indications
and clinical impact of US-guided therapeutic interventions and gives evidence-based
recommendations for the safety and efficacy of these techniques using the available
evidence at the time of manuscript preparation. It is complemented by guidelines on
general aspects of US-guided interventions (part I) [1] and US-guided diagnostic interventions (part II) [2]. In addition, EFSUMB also will publish guidelines on the use of diagnostic and therapeutic
endoscopic ultrasound [3]
[4] and ultrasound-guided vascular interventions [5].
Methods of guideline development are described in the introduction to the EFSUMB Guidelines
on Interventional Ultrasound [6]. Levels of evidence (LoE) and grades of recommendations (GoR) have been assigned
according to the Oxford Centre for Evidence-based Medicine criteria (March 2009 edition)
[http://www.cebm.net/oxford-centre-evidence-based-medicine-levels-evidence-march-2009].
Local ablative procedures
Local ablative procedures
Introduction
Local ablative procedures play a key role in the management of patients with malignancies,
primarily with hepatocellular carcinoma (HCC), but also with metastases [7]
[8]
[9]
[10].
Treatment intention
Local ablative procedures can be classified according to the treatment intention as
curative or palliative [11]
[12].
Curative intention
Tumor ablation is usually performed with curative intent. This applies mainly to small
HCCs (≤ 5 cm), as well as to colorectal liver metastases [12]
[13]
[14]
[15]
[16]
[17]
[18]. The decision for local ablation over resection should take into account data such
as the patient’s age, co-morbidities, normal parenchymal reserve and tumor distribution
inside the liver, as well as the risks for metachronous tumor growth, and all these
should be weighed against the invasiveness of the procedure [11].
HCC ablation should be preferably performed with curative intent (LoE 1a, GoR A).
Strong consensus (100 %).
Palliative strategy
The main indication for palliative treatment of liver tumors is metastatic neuroendocrine
tumor load. Other primary [19] and secondary liver tumors may also be treated [11]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
[27].
Combined treatment options
With multiple liver metastases (commonly colorectal) not suitable for surgical resection
because of their number or location (e. g., proximity of vascular or biliary structures),
a combined approach should be considered [28].
Ablation in conjunction with resection is increasingly used as a parenchyma-sparing
curative strategy that combines effective ablative treatment of small tumors with
resection of large tumors, for which ablation is less effective [29]
[30]
[31]
[32]
[33]
[34]
[35]
[36]. Similar concepts can be applied to hepatocellular carcinoma (HCC) in a cirrhotic
liver, when extensive surgical sacrifice of the parenchyma must be avoided.
Ablation in conjunction with resection may be considered as a parenchyma-sparing curative
strategy (LoE 2a, GoR B). Strong consensus (100 %).
Hepatocellular carcinoma (HCC)
The treatment options for HCC in a cirrhotic liver are transplantation, surgical resection,
local ablative therapies, transarterial chemoembolization (TACE), radioembolization
with Yttrium90 loaded beads (transarterial radioembolization) (TARE), and, in cases
of advanced disease, systemic therapy with sorafenib (Nexavar®). Image-guided percutaneous ablation therapies, such as radiofrequency ablation (RFA)
[37]
[38]
[39], percutaneous ethanol injection (PEI) [40]
[41]
[42] and microwave ablation [43], have been performed mainly with small HCCs, according to the Milan criteria [44]. These are potentially curative, minimally invasive, and repeatable in case of recurrence
[45].
Local ablative treatment techniques for HCC
Size of tumors
As a single RFA needle usually coagulates a region of about 2 cm in diameter, potentially
non-spherical (depending on the RF system) multiple sequential insertions may be required
to achieve a safety margin.
To overcome this limitation, multi-needle systems have been introduced for simultaneous
ablations and stereotactically guided RFA [46]
[47]
[48]
[49]. There is no accepted maximum tumor size that can be ablated in a single session
but the size is generally in the 4 to 5 cm range. The ablated zone should encompass
the treated tumor and a circumferential margin of 5 – 10 mm around the tumor [50].
Location of tumors
HCC tumors in a subcapsular location or adjacent to the gallbladder have a higher
likelihood of incomplete ablation [51] or major complications [52]
[53]
[54].
To reduce the number of complications, attention must be paid to vulnerable structures
close to the tumor or the ablation zone. This applies to the porta hepatis, gallbladder,
stomach, small intestine and colon, all of which are particularly sensitive to thermal
damage [55]
[56]. In case of subdiaphragmatic lesions, pulmonary, pleural or cardiac heat damage
might occur, usually with only minor clinical significance [57]
[58].
Number of tumors
The maximum number of tumors that can be ablated in a single procedure is not clearly
defined, but ranges from 3 to 5 in most centers [11]. Overall survival is best for patients with solitary tumors, intermediate for those
with 2 to 3 tumors, and worst for those with ≥ 3 tumors [59].
The maximum recommended diameter of HCC lesions treatable with thermal ablation is
generally considered below or equal to 5 cm, although optimal results are obtained
in lesions < 3 cm (LoE 2b, GoR B). Strong consensus (100 %).
The ablation zone should aim to extend at least 5 mm beyond the visible borders (LoE
3a, GoR B). Strong consensus (100 %).
In lesions close to large vessels and heat-sensitive structures, alternative or additional
techniques should be considered (LoE 3a, GoR B). Strong consensus (100 %).
Three to five HCCs are the recommended maximum number of lesions in a single session
that allows percutaneous ablation with curative intent (LoE 2a, GoR B). Strong consensus
(100 %).
RFA versus surgical resection in small HCCs
There is inconclusive evidence as to whether RFA is as effective as surgical resection
as the first-line treatment for patients with small, solitary HCCs [50]
[51]
[53]
[54]
[55]
[56]
[60]
[61]
[62]
[63]. A systematic review of 8000 patients [64] with a current Cochrane analysis [65] reported uncertainty regarding the question of the impact of RFA versus surgery.
However, a more recent meta-analysis, published after the Cochrane analysis [66], showed that there were differences in age and liver function between patients with
early HCC submitted to either RFA or resection. When the analysis was corrected for
these parameters, no survival differences were observed between RFA and surgery in
single HCCs < 2 cm or 2 – 3 HCC tumors < 3 cm, whereas surgery resulted in a longer
survival in the case of single HCCs measuring 2 – 5 cm [66]. Mortality and morbidity rates of RFA have been reported to be 0 – 1.5 % and 0.9 – 7.9 %,
respectively [67]
[68]
[69]
[70]
[71]
[72].
Percutaneous ethanol injection (PEI)
PEI was the first ablative procedure, initially reported in the early 1980 s [40]
[41]
[73].
The procedure is inexpensive and safe, with low mortality and morbidity (0 – 3.2 %
and 0 – 0.4 %, respectively) [74]
[75]
[76]. Even though RFA has replaced PEI [38]
[77]
[78], PEI can be offered in small HCCs, mainly those for which RFA is not feasible due
to tumor location.
RFA versus PEI
Randomized controlled trials comparing RFA with PEI demonstrate that RFA is superior
to ethanol injection in terms of treatment response, number of sessions, recurrences,
and overall survival [77]
[78]
[79]
[80]
[81]
[82]
[83] as further supported by meta-analyses [65]
[82]
[84].
The efficacy of the methods is similar for tumors ≤ 2 cm [38]
[77]
[78]
[85]. Meta-analyses, including randomized controlled trials (RCTs), confirmed that treatment
with RFA offers a survival benefit as compared to PEI in tumors > 2 cm [82]
[83]
[84]
[86]
[87]. RFA has a slightly higher rate of major complications (4 %; 95 % CI, 1.8 – 6.4 %)
as compared to PEI (2.7 %; 95 % CI, 0.4 – 5.1 %) [52]
[79]
[81]
[87]. The best results obtained in series of HCC patients treated by RFA provided 5-year
survival rates of 40 – 70 % or higher in select groups of patients [47]
[67]
[88]. The best outcomes have been reported in Child–Pugh A patients with small (< 2 cm)
single tumors [70]
[89]. Independent predictors of survival with RFA are initial complete response, Child–Pugh
score, number or size of nodules, and baseline alpha-fetoprotein levels [90].
Other procedures
Percutaneous microwave ablation (MWA) was introduced into clinical practice in the
1990 s [43]
[91]
[92]
[93]
[94]
[95]
[96]
[97].
Selection of ablation technique
With PEI, local response is related to tumor size. PEI has yielded very favorable
results for small encapsulated HCCs (< 2 cm) [12]
[73]. HCC encapsulation by a cirrhotic liver prevents satellite nodules from being reached,
leading to higher rates of local recurrence in comparison to RFA [98]
[99]
[100]
[101]).
Percutaneous ethanol injection with curative intent is an alternative to thermal ablation
in encapsulated HCCs < 20 mm (LoE 2a, GoR B). Broad agreement (95 %).
Percutaneous ethanol injection can be an alternative in case of contraindications
to thermal ablation (LoE 3b, GoR B). Broad agreement (79 %).
Selection of imaging modality (ultrasound, CT, MRI)
US is the first-line imaging modality for local ablative procedures in the liver.
CT guidance can be an alternative, particularly when US guidance is not feasible anatomically
or with US imaging of occult lesions [102]
[103]. MRI guidance is possible but with limited availability and major costs. Local expertise
and personal experience determine the modality of choice. Contrast-enhanced imaging
must be available during the interventional procedure to confirm the completeness
of necrosis. Fusion imaging is an alternative technique that can be used for the guidance
of the procedure.
Planning and monitoring ablation treatment
Imaging plays an important role before, during and after ablation procedures. Assessment
of tissue perfusion is crucial to differentiate necrotic areas from viable residual
tumor. With US-and CT-guided RFA, this requires evaluation with contrast-enhanced
imaging during and immediately after ablation. Contrast-enhanced ultrasound (CEUS)
can provide important information for assessment during and immediately after ablation
[104]
[105]:
-
assessment of the lesions to be treated by ablation (number, size, degree and homogeneity
of lesion enhancement, presence of feeding vessels, to define the eligibility for
treatment and the best ablation strategy)
-
depiction of previously undetectable lesions with the support of fusion imaging, enabling
needle/probe guidance to occult lesions
-
detection of viable tumor persistence following loco-regional treatment [50]
CEUS is the most effective method to define local recurrence in a treated nodule because
of its real-time capability, the intra-vascular characteristic of the contrast agent
and the near-total differentiation between the displayed contrast and background information
of current imaging methods [8]. CT and MRI provide better overviews of the liver and adjacent organs, which are
necessary for pretreatment staging and useful to detect distant intra- and extra-hepatic
tumor recurrence.
Complications
Studies have established that RFA is a low-risk procedure [106]
[107]
[108]
[109], with a mortality of 0.1 – 0.8 % and few adverse events. Major complications occur
in 2.2 – 11 % of RFA-treated patients [72]
[106]
[110]
[111]
[112]. Bleeding, infection, arteriovenous fistula formation, bile duct damage, and tumor
seeding are possible complications of local ablative therapy [11]
[12]
[18]
[113].
Thermal track ablation can potentially reduce the likelihood of tumor seeding in HCC
ablation to below 1 % [114]
[115]
[116]
[117].
A multidisciplinary approach to assess patients with HCC in liver cirrhosis for possible
transplantation is recommended prior to alternative treatments (LoE 5, GoR D). Strong
consensus (100 %).
RFA with curative intent is an alternative, more cost-effective technique in comparison
to surgery in early HCC BCLC-0 (HCC < 2 cm) (LoE 2a, GoR B). Strong consensus (100 %).
RFA with curative intent should be considered as a second-line treatment in single
HCCs 2 – 5 cm in Child-Pugh A patients, after the patient has been evaluated for surgical
resection (LoE 2b, GoR B). Strong consensus (100 %).
RFA with curative intent should be considered as the first-line treatment in Child-Pugh
B patients with single HCCs < 5 cm or in patients with 2 or 3 HCCs < 3 cm (LoE 2b,
GoR B). Strong consensus (100 %).
Solitary HCCs > 3 cm not suitable for surgery should be considered for combined loco-regional
treatments (LoE 4, GoR C). Broad agreement (95 %).
Colorectal cancer liver metastases
It is estimated that 50 – 60 % of patients with colorectal cancer (CRC) will develop
liver metastases [118]. The most successful treatment for hepatic metastases is surgical resection [9]
[10]
[31]
[59]
[119]
[120]
[121]
[122]
[123]
[124]
[125]. However, approximately 50 – 70 % of these patients will develop recurrence [126].
Local ablative procedures with curative intent have a role in the management of CRC
liver metastases [9]
[10]. Depending on the size of the lesions, RFA may be performed alone or combined with
resection [127]. Several studies have demonstrated that RFA achieved permanent local ablation of
liver metastases and a 5-year survival of 24 % to 43 % [128]
[129]
[130]
[131]
[132]. These results are comparable to surgery [31]
[59]
[119]
[120]
[121]
[122]
[123]
[124]
[125]. Local recurrence occurs more frequently after ablation than with resection [9]
[10]
[133].
Two meta-analyses confirmed that surgery is superior to RFA with regard to survival
outcomes in patients with resectable CRC liver metastases [134]
[135]. The first RCT on the efficacy of RFA combined with chemotherapy versus chemotherapy
alone was underpowered; RFA plus systemic treatment resulted in significantly longer
progression-free survival (PFS) compared with chemotherapy alone [136].
Percutaneous thermal ablation with curative intent is a second-line alternative to
surgery in patients with colorectal liver metastases (LoE 2a, GoR B). Strong consensus
(100 %).
The maximum diameter of metastatic lesions treatable with thermal ablation is generally
considered ≤ 4 cm, although better results are obtained in lesions < 3 cm (LoE 5,
GoR D). Strong consensus (100 %).
The ablation zone should aim to extend at least 10 mm beyond the visible borders (LoE
5, GoR D). Broad agreement (94 %).
Other liver metastases
Percutaneous thermal ablation or PEI may be a therapeutic option for neuroendocrine
liver metastases [23]
[24].
Renal malignancies treated with local ablative therapy
Introduction
Possible treatment options for renal cell carcinoma (RCC) are [137]:
-
Surgery, either nephrectomy or nephron-sparing (open or laparoscopic)
-
Local ablative procedures (percutaneous or laparoscopic)
-
Active surveillance
Small masses
Standard therapy for small RCCs is nephron-sparing surgery. Local ablative techniques
have evolved into alternative procedures, showing excellent results [138].
Tumors < 4 cm in diameter are ideal candidates for ablative techniques. The volume
to be treated should include a 5 – 10 mm safety margin [139]. Most tumors < 3 cm can be treated in a single ablation session. Tumors between
3 – 4 cm in diameter can also be successfully treated, although multiple ablation
sessions may be required [140]
[141]
[142]
[143]
[144]
[145]
[146]
[147]
[148].
Patients with RCCs < 3 cm with significant surgical risk or requirement for nephron-sparing
strategy should be considered for local ablative therapy (LoE 2b, GoR B). Strong consensus
(100 %).
RCTs comparing surgery and local ablative therapy have not been performed [137]
[149]. Cancer-specific survival is similar for both methods [150]
[151]. The European and American Urological Associations recommend thermal ablation as
a treatment option for patients with a T1 renal mass [152].
Local recurrence-free survival following image-guided tumor ablation is 87 % [153]. The local recurrence of percutaneously performed RFA is estimated at 2.5 – 14 %
[154]. Cancer-specific survival of patients treated with RFA is comparable to patients
treated with surgery [142]
[152]
[155]. Both cryotherapy and RFA had a higher risk of recurrence compared to partial nephrectomy
[156], but re-intervention is straightforward [142].
The rate of major complications for cryotherapy is 5 %, which is lower than for surgery
[152], the most common complication being hemorrhage [213] with 2 % developing distant metastases [152]
[155]. Post-procedural ureteric strictures have also been documented [152]. Cryotherapy is preferred over RFA in central tumors in contact with the renal hilum
or the ureter [157].
RCC histology should be obtained prior to ablation (LoE 4, GoR C). Broad agreement
(81 %).
CEUS can be used for surveillance after RFA of RCCs in order to detect local recurrence
and to assess for liver metastases [158]. CT of the thorax and abdomen is necessary to exclude metachronous extrahepatic
metastases. No RCTs have been performed [159]
[160]
[161].
Contrast-enhanced ultrasound or CT or MRI should be performed in the follow-up after
RCC ablation, unless contraindicated (LoE 4, GoR C). Strong consensus (100 %).
Abscess drainage
US-guided percutaneous drainage of abdominal abscesses is a well-established interventional
procedure first described in 1974 [162] and is currently the first-line treatment approach for abdominal abscesses.
Definition and classification
Differentiation between phlegmonous inflammation and abscesses is of importance for
treatment guidance. An abscess is a pus-containing confined collection, most often
caused by bacteria. To be termed an abscess, the fluid has to be viscous and surrounded
by an inflammatory wall that develops as a result of effective host defense [163].
Phlegmonous infections and small abscesses should be treated with antibiotics and
require no drainage (LoE 5, GoR D). Strong consensus (100 %).
Postoperative fluid collection
Fluid collections present on postoperative imaging, localized or generalized (“free
fluid”), are common and nonspecific which may represent different pathological entities
such as hematoma, exudate, seroma, biloma, lymphocele or an abscess. Fluid seen on
imaging is often not characteristic; any patient with a clinical suspicion of an abdominal
abscess should have a diagnostic aspiration to guide further management. Sterile fluid
collections can become infected postoperatively, requiring diagnostic aspiration and
eventually therapeutic drainage.
Ultrasound (US)
US imaging is often the initial modality used in abscess delineation as it allows
dynamic evaluation and real-time guidance of needling. Depending on the contents,
an abscess can be anechoic, hypoechoic and even hyperechoic. CEUS can be helpful in
differentiating vascularized from avascular areas [164]
[165].
CT is indicated in technically limited US examinations or inconclusive results.
Diagnostic aspiration
A US-guided diagnostic puncture of a fluid collection with a fine needle or a larger
needle (depending on the viscosity) can distinguish an abscess from a non-infected
fluid collection.
Diagnostic aspiration of a suspected infected fluid collection is recommended (LoE
5, GoR D). Strong consensus (100 %).
Puncture and drainage
Catheter drainage versus needle aspiration
A meta-analysis of 5 RCTs comparing catheter drainage and repeated needle aspirations
of liver abscesses demonstrated catheter drainage to be more effective, with higher
success and shorter time to achieve clinical improvement [166]. Studies of abdominal abscesses of various etiologies have shown good results with
repeated needle aspiration in simple abscesses < 5 cm. In larger abscesses catheter
drainage performed better than repeat needle aspiration [167]
[168]
[169]
[170]
[171].
Abscesses less than 5 cm in diameter can be treated with needle aspiration (LoE 2b;
GoR B). Strong consensus (100 %).
Catheter drainage is more effective than needle aspiration in abscesses larger than
5 cm in diameter (LoE 1a, GoR A). Broad agreement (89 %).
Small or large catheters
No difference in outcome was seen in a study of intra-abdominal abscesses treated
with 7F pigtail catheters and 14F sump drain catheters [172]. Currently large catheters (> 10F) should be reserved for complex abscesses containing
thick pus and debris.
Catheters of 7 – 10F in size are recommended for the treatment of most abscesses,
regardless of abscess dimensions (LoE 4, GoR C). Broad agreement (90 %).
Large catheters (> 10F) should be reserved for complex abscesses with thick contents
(LoE 5, GoR D). Broad agreement (90 %).
Catheter introduction techniques: Trocar versus Seldinger
Two techniques are used for the insertion of a drainage catheter: the trocar (one-step)
technique and the Seldinger (two-step) technique. Both have advantages and disadvantages
and can be performed with either a free-hand or needle-guided technique, depending
on the preference and experience of the operator.
The trocar technique is suitable in most circumstances using catheters ≤ 10 F (LoE
5, GoR D). Broad agreement (93 %).
The Seldinger technique is recommended when access is difficult, for large catheters,
and for catheter replacement (LoE 5, GoR D). Broad agreement (86 %).
Single versus double lumen
Double lumen catheters are not recommended since they combine the negative features
of large diameters and relatively small lumens.
Double lumen catheters are not recommended (LoE 5, GoR D). Broad agreement (94 %).
Abscess cavity extension and complexity, fistula, and contrast injection (X-ray, CEUS)
Treatment planning requires careful assessment of the size, shape, content and extent
of the abscess, including identification of associated fistulas. Fistulography (or
abscessography, sinography) with intracavitary injection of iodinated contrast media
under CT or fluoroscopic guidance has been the recommended technique. Direct injection
of US contrast agent through the needle or catheter has been reported to facilitate
confirmation of correct needle or catheter position and allows evaluation of any communication
between cavities in complex abscesses at the bedside [173]
[174]
[175].
Intracavitary CEUS may add value regarding needle and catheter position, cavity morphology
and presence of fistulas (LoE 4, GoR C). Strong consensus (100 %).
Specific organs and locations
Liver abscess
Pyogenic liver abscesses are often the result of biliary obstruction caused by benign
or malignant diseases with consequent cholangitis. For percutaneous drainage, a transhepatic
access route is preferred for direct puncture to avoid spillage of pus into the peritoneal
cavity. Small amebic abscesses generally respond to conservative treatment and do
not require drainage, but large amebic abscesses may need drainage [176].
The origin of liver abscesses should be investigated to search for an underlying cause
(LoE 5, GoR D). Strong consensus (100 %).
A transhepatic access route is recommended for the percutaneous drainage of hepatic
abscesses (LoE 5, GoR D). Strong consensus (100 %).
Splenic abscess
Splenic abscesses are rare, except in immunocompromised patients. Splenic puncture
or biopsy is relatively safe as documented in a meta-analysis [177].
Percutaneous splenic abscess drainage should be the first-line treatment and surgery
should be performed in the case of treatment failure (LoE 4, GoR C). Broad agreement
(89 %).
Pancreatic abscess
Percutaneous drainage of pancreatic abscesses is often prolonged and may require multiple
catheters. The percutaneous approach offers quick access for severely ill patients.
As a second stage procedure, conversion to internal drainage with an endosonographic
approach should be considered.
Pancreatic abscess management is complex and often prolonged. Drainage procedures
guided by transcutaneous or endoscopic ultrasound (EUS) should be considered (LoE
4, GoR C). Broad agreement (89 %).
Enteric abscess
Abscesses are frequent complications of Crohn´s disease, diverticulitis and appendicitis.
In Crohn´s disease, there is no study comparing percutaneous and surgical drainage
of abscesses. Percutaneous drainage of Crohn’s-related abscesses has a high success
rate, demonstrated in several studies and is the first-line treatment [178]
[179]. With early percutaneous drainage, (non-elective) surgery can often be avoided (14 – 85 %
of patients) [179]
[180]
[181]
[182]
[183].
Abscesses can be detected in 15 % of patients with acute diverticulitis [184]
[185]. Antibiotics successfully treat smaller abscesses (< 3 cm) [184]
[186]
[187], but larger abscesses (> 3 cm) require percutaneous drainage [188]
[189]. Peri-appendicular abscesses can occur either as a result of rupture of an infected
appendix or post-operatively.
It is generally accepted that a peri-appendicular abscess will respond to percutaneous
drainage. Leakage of enteric contents at an anastomosis may lead to abscess formation,
which most often requires reconstructive surgery. Sometimes, a non-surgical approach
is preferred with usage of long-term percutaneous drainage with large catheters.
Abscesses in Crohn´s disease, diverticulitis and appendicitis may benefit from percutaneous
drainage as the first-line strategy (LoE 4, GoR C). Broad agreement (89 %).
Abscess in the lower abdomen and pelvis
For deep pelvic abscesses, alternative puncture routes are available. Transrectal,
transvaginal, transperineal and transgluteal accesses have all been shown to be useful
and safe [169]
[190]
[191]
[192].
US-guided drainage by transrectal, transperineal or transvaginal access is associated
with a low risk of complications and should be considered for deep pelvic abscesses
(LoE 4, GoR C). Strong consensus (100 %).
Use of intracavitary fibrinolytics is not routinely recommended (LoE 5, GoR D). Broad
agreement (94 %).
Ultrasound-guided paracentesis
Ultrasound-guided paracentesis
Background
Paracentesis is performed either as a diagnostic or as a therapeutic procedure, in
the presence of ascites or suspected bacterial peritonitis. Therapeutic paracentesis
provides almost immediate symptomatic relief and is usually well tolerated.
Technical issues
Ascites drainage is usually easily and safely performed by inserting a 14 – 18 gauge
needle (including paracentesis-specific devices) or as a one-step catheter under US
guidance. Catheters can be pig-tail, they can have an internal string for internal
loop fixation, or an internal balloon fixation can be used. A small bore catheter
(between 5F and 7F) is usually adequate.
US guidance offers real-time imaging of the needle tip and surroundings during the
procedure, making it safe and effective. In most instances, US assistance (i. e.,
US utilized to select the best access point prior to blind needle insertion) is as
safe as US guidance [193].
Complications
Paracentesis is considered a safe procedure, carrying a 1 % risk of overall complications,
which include leakage of ascitic fluid, local infection, abdominal wall hematomas,
intraperitoneal hemorrhage, and intestinal perforation [194]. It is recommended to follow strict antiseptic practices in all patients [195]. Ultrasound guidance can reduce the risk of complications after paracentesis [193]
[196].
Ultrasound-guided or assisted paracentesis is a low-risk and effective procedure (LoE
4, GoR C). Strong consensus (100 %).
Specific considerations
Cirrhosis
Ascites is the most common complication of cirrhosis leading to hospital admission.
Albumin administration
Large-volume paracentesis (> 5 L) is generally an effective and safe procedure, but
it does carry a risk of “postparacentesis circulatory dysfunction” (PCD).
Administration of albumin is mandatory in large-volume (> 5 liters) paracentesis (LoE
1a, GoR A). Strong consensus (100 %).
There are no established preprocedural threshold coagulation levels that preclude
paracentesis (LoE 5, GoR D). Broad agreement (94 %).
Palliative paracentesis for malignant ascites
Malignant ascites accounts for around 10 % of cases and occurs with a variety of neoplasms
[197]. Large amounts of ascites can cause increased abdominal pressure with pain, dyspnea,
loss of appetite, nausea, and reduced mobility. Long-term paracentesis is indicated
for patients with symptoms of increased intraabdominal pressure caused by recurring
malignant ascites despite repeated paracentesis.
Permanent catheter drainage should be considered for terminally ill patients with
refractory ascites (LoE 4, GoR C). Broad agreement (94 %).
Sclerotherapy of non-parasitic cysts
Sclerotherapy of non-parasitic cysts
Hepatic cysts
Hepatic cysts have a prevalence of 2.5 – 7 %. Most are asymptomatic and do not need
treatment [198]. Percutaneous treatment, consisting of aspiration of cystic fluid followed by injection
of a sclerosing agent, is usually performed with US guidance, as a minimally invasive
option for large or symptomatic cysts.
Indications
Large cysts (> 6 – 10 cm), which are symptomatic (pain or infected) or causing space-occupying
effects (abdominal distension, obstructive jaundice or both), require treatment. Other
less established indications include symptomatic small sub-capsular cysts located
at sites exposed to mechanical stress (beneath the ribs or sternum) [199]. In polycystic liver disease, any cysts may be treated if causing symptoms or to
avoid complications (e. g., rupture, bleeding, infection) [200]
[201]
[202]
[203]
[204]
[205].
With symptomatic or compressive hepatic cysts, percutaneous sclerotherapy or surgery
should be considered (LoE 4, GoR C). Strong consensus (96 %).
Contraindications
Caution is required when treating hydatid cysts; the nature of a cyst may not be known
prior to aspiration [199]. A relative contraindication is hemorrhagic cysts [206] although they can be treated with similar results once infection or malignancy has
been excluded [202]. Ascites and planned liver transplantation are other relative contraindications.
Multidisciplinary decision making
Multidisciplinary decision (gastroenterologists, surgeons, interventional radiologists)
for the procedure is mandatory as other options include open surgery and laparoscopic
deroofing which are effective treatments. These treatments are associated with substantial
morbidity and mortality and require expertise [207]
[208]. Percutaneous treatments have similar efficacy, allowing surgery to be reserved
for complicated cases or if percutaneous sclerotherapy fails [201]
[209].
Sclerotherapy versus surgery (fenestration)
No randomized prospective study comparing fenestration and sclerotherapy has been
published. In most centers, sclerotherapy is attempted first as a noninvasive option,
and laparoscopic fenestration is indicated in refractory cases [209].
Percutaneous ethanol sclerotherapy is a good alternative to laparoscopic deroofing
with similar efficacy and lower complication rates (LoE 4, GoR C). Strong consensus
(96 %).
Prognosis
The majority of patients who undergo percutaneous sclerotherapy are symptomatically
improved immediately following the procedure, but only 20 % will have partial or full
regression of the dominant and symptomatic cyst [208]. In polycystic liver disease both sclerotherapy and surgery are disappointing (77 – 100 %
recurrence rate) [9].
Materials and technical issues
The treatment consists of evacuation of the cystic contents (either by aspiration
or drainage via a catheter) followed by sclerotherapy of the inner epithelium using
standard agents (ethanol, polidocanol, tetracycline chloride, minocycline chloride,
hypertonic saline solution and ethanolamine oleate) [210]
[211]
[212]
[213]
[214]. A radiopaque contrast medium or US contrast agent should be instilled into the
cyst to exclude a connection with the biliary tree [215]. If contrast medium enters the bile ducts, sclerotherapy is contraindicated.
Ethanol sclerotherapy
Ethanol (95 – 98 % concentration) is most commonly used for sclerotherapy of hepatic
cysts [216]
[217]
[218]. Single or multiple sessions may be needed with evacuation of the fluid content
performed using 6 – 8F catheters or a Chiba needle (18 – 20 gauge) [216]
[217]
[218]. After ethanol sclerotherapy, an 80 – 100 % reduction of cyst volume may be achieved
[198]
[201]
[210]
[216]
[218]
[219].
The main complications during ethanol sclerotherapy are pain, ethanol-induced fever
or hyperthermia, intoxication, intra-cystic bleeding and iatrogenic pleurisy or peritonitis
[202]
[211].
With percutaneous ethanol sclerotherapy of large liver cysts, the use of small catheters
instead of needles should be considered to achieve a longer ethanol exposure time
(LoE 4, GoR C). Broad agreement (95 %).
Sclerotherapy using other substances
Several other substances with better safety profiles, ease of use and low cost have
been tested with good results and few complications [210]
[211]
[212]
[213]
[214]. Polidocanol 1 – 3 % (aethoxysklerol) may be preferred for its local anesthetic
properties (it is less painful than alcohol) and its slight bactericidal activity
[199].
Percutaneous sclerotherapy using other substances is an alternative to ethanol (LoE
4, GoR C). Broad agreement (90 %).
Ultrasonographic follow-up
In polidocanol therapy maximum volume reduction occurred 1 year after the procedure
[215]. Follow-up examinations may only be necessary in symptomatic patients.
Renal cysts
Indications
Simple renal cysts are mostly asymptomatic and do not require treatment. In 2 – 4 %
the cyst may become symptomatic because it enlarges or develops complications such
as hemorrhage, infection, rupture or compression [220]. Cysts that develop adjacent to the renal hilum may obstruct the urinary tract [221]. US-guided cyst aspiration with or without sclerosing therapy is a minimally invasive,
simple, safe and low-cost procedure [221].
Symptomatic simple renal cysts should be considered for treatment. (LoE 4, GoR C).
Broad agreement (94 %).
Multidisciplinary decision making
A multidisciplinary decision regarding procedure choice is recommended as surgical
excision via open, percutaneous, laparoscopic or robotic surgery is effective but
more invasive. Laparoscopic deroofing achieves better results than percutaneous sclerotherapy
(PS) [220]
[221].
The decision on treatment modality should consider that percutaneous sclerotherapy
is less invasive and associated with lower risks than laparoscopic deroofing, but
has lower efficacy (LoE 2b, GoR B). Broad agreement (88 %).
Materials and technical aspects
A variety of substances are used for sclerotherapy of the cystic wall [214]
[222]
[223]
[224]
[225]
[226]
[227]
[228]
[229]
[230]
[231] as described for liver cysts.
Simple cyst drainage without sclerotherapy
After simple aspiration, the recurrence ranges from 30 – 80 % [171]
[232].
Simple aspiration should not be used in the treatment of renal cysts because recurrence
is frequent (LoE 4, GoR C). Broad agreement (93 %).
Ethanol sclerotherapy
The most common sclerotherapy agent for renal cysts is ethanol [227]
[228]
[229]
[230]
[231]. A concentration of 95 – 99 % destroys the secreting cells of the cyst wall without
affecting the renal parenchyma [220]. Single or multiple sessions have been used, with better results but with higher
complications for multiple sessions [221]
[228]
[229]
[230]
[231]
[232]
[233].
The main complications that may occur during ethanol sclerotherapy are pain, fever,
and systemic reactions [220].
Multiple sessions and/or prolonged drainage should be used to reduce recurrence in
symptomatic large renal cysts treated with ethanol sclerotherapy (LoE 4, GoR B). Broad
agreement (87 %).
Ultrasonographic follow-up
Follow-up examinations may only be necessary in symptomatic patients.
Abdominal echinococcal cysts, puncture, aspiration, injection and re-aspiration (PAIR)
Abdominal echinococcal cysts, puncture, aspiration, injection and re-aspiration (PAIR)
Introduction
Echinococcosis is a chronic, complex and neglected zoonosis with widespread global
distribution. 70 % of cases of cystic echinococcosis (CE) are located in the liver
[234]. US has an important role in the diagnosis, treatment and follow-up of abdominal
CE and is established in the interventional treatment of abdominal CE [235]
[236].
Classification
The WHO echinococcal cyst classification [237]
[238] is US-based and was introduced to guide treatment options and to predict prognosis
[239]. Type CE1 and CE2 are the typical active cysts. Type CE1 is unilocular, whereas
CE2 is multilocular with daughter cysts. The Gharbi classification is still widely
used [240].
Diagnosis and differential diagnosis
Imaging
US is the imaging modality most appropriate for diagnosis and differential diagnosis
[238], while US guidance is usually used for intervention [241]
[242].
Serological tests
Serological tests for echinococcosis should be obtained, where available, before the
procedure [243]
[244].
PAIR indication
PAIR is most appropriate for CE1 and CE3a according to the WHO classification (Gharbi
type I and II cysts) [244]
[245].
Relative contraindications
Hydatid cysts with multiple daughter cysts and solid components (Gharbi Type III-IV
and WHO CE2-CE3b) are not suitable for PAIR [236]
[245]
[246]. It is reported that aggressive percutaneous evacuation for these complex cysts
is useful, but not widely accepted.
Pretreatment procedures
As with any interventional procedure, the patient should be carefully evaluated before
the PAIR procedure. Albendazole should be started one week (or at least one day) prior
to the procedure for prophylaxis against abdominal contamination [247], and thereafter continued for at least one month [236]
[248].
Procedure, puncture and drainage
The procedure consists of puncture, aspiration, injection and re-aspiration [239]
[249]
[250] using a 20-gauge fine needle [251]
[252].
Outcome
RCTs showed PAIR to be superior to albendazole alone [253] and to surgical treatment [239]
[254]. PAIR combined with albendazole was more effective than surgery and was associated
with a lower rate of adverse events and a shorter hospital stay. Retrospective studies
favor PAIR over surgery in Gharbi type I and II cysts and found surgical treatment
most appropriate in the other Gharbi types [249]
[255].
A meta-analysis reported severe adverse events (anaphylaxis, cyst infection, abscess,
sepsis, biliary fistula) in 7.9 % of patients treated with PAIR plus albendazole [256].
US-guided PAIR is the most appropriate treatment for WHO CE1 and CE3a abdominal hydatid
cysts (LoE 2b, GoR B). Strong consensus (100 %).
PAIR should always be accompanied by measures to manage possible anaphylaxis (LoE
5, GoR D). Broad agreement (93 %).
Albendazole should be started prior to PAIR (LoE 2b, GoR B). Strong consensus (100 %).
Percutaneous transhepatic cholangiodrainage (PTCD)
Percutaneous transhepatic cholangiodrainage (PTCD)
Introduction
Percutaneous transhepatic cholangiography and drainage (PTCD) is a commonly used procedure
for the diagnosis and treatment of benign and malignant biliary diseases [257]
[258]. PTCD also allows therapeutic interventions, such as placement of a stent across
a malignant stricture, dilatation of benign biliary strictures and extraction of biliary
tract stones [259].
Endoscopic retrograde cholangiography versus PTCD versus endoscopic ultrasound-guided
cholangiodrainage
Endoscopic retrograde cholangiography (ERC) is the method of choice for patients with
indications for (therapeutic) biliary access [260]
[261]. The following surgically altered anatomical situations have a high likelihood for
ERC failure: Roux-en-Y with gastric bypass, Kausch-Whipple resection, pylorus-preserving
Whipple resection, Roux-en-Y with hepaticojejunostomy, choledochojejunostomy, and
pancreaticojejunostomy [262].
Alternative methods are PTCD, EUS-guided interventions (EUS cholangiodrainage, EUS-CD)
[192] and balloon-assisted enteroscopy (BAE).
Special problems
Ultrasound guidance versus fluoroscopic guidance
A blind percutaneous puncture of peripherally located intrahepatic bile ducts has
limitations especially with non-dilated bile ducts [263]
[264]. Real-time imaging with US is useful for the guidance of PTCD (US-PTCD), especially
in patients with non-dilated ducts and for left-sided PTCD [265]
[266]
[267]. Fluoroscopy delivers significant irradiation both to the patient and to the interventional
team. The “As Low As Reasonably Achievable” (ALARA) principle should be applied [268].
For initial puncture in PTCD ultrasound guidance should be considered (LoE 4, GoR
C). Strong consensus (100 %).
Percutaneous cholecystostomy
Percutaneous cholecystostomy
Introduction
Acute calculous cholecystitis (ACC) is a common cause of acute surgical admission.
Early cholecystectomy (CCE) is a widely accepted method of treatment [269]. Laparoscopic cholecystectomy (LCCE) in acute cases has minimal morbidity [270]. In high-risk patients morbidity and mortality increase to 14 – 46 % [271].
Alternatively, percutaneous cholecystostomy (PC) is a bridging process, especially
in otherwise healthy patients (e. g. ASA I and II) who are severely septic and may
become fit in due course for semi-elective surgery [272].
Clinical efficacy
A meta-analysis of 53 studies (n = 1918 patients) reported successful PC for 85.6 %
of patients. The procedure-related mortality rate of PC was 0.4 % [273].
Evaluation of US-guided percutaneous cholecystostomy (USPC) for patients with acute
acalculous cholecystitis (AAC) is more difficult because it is normally a complication
of serious medical and surgical illnesses [274]
[275]. A study compared clinical efficacy and adverse events of PC and CCE in a large
group of severely ill patients with AAC and showed PC to be a safe and cost-effective
bridging treatment strategy, with perioperative outcomes superior to those of open
CCE. Compared with open or laparascopic CCE (n = 1021), PC (n = 704) was superior
in terms of morbidity, intensive-care unit admissions, length of hospital stay, and
costs [276]. Two studies showed that in seriously ill patients with AAC, PC is an effective
procedure and may be regarded as a definite treatment option in the majority of patients
[277]
[278].
Data is limited with respect to the duration of gallbladder drainage. Before removal
of the drain, laboratory and clinical data should confirm resolution of sepsis [279]. Patients should be re-evaluated following recovery to assess fitness for elective
surgery. Cholecystitis recurrence of 10 – 30 % is reported, and should be weighed
against the mortality and morbidity risk in the individual patient.
Percutaneous ultrasound-guided gallbladder drainage may be considered in patients
with acute calculous cholecystitis assessed to be unfit for surgery (LoE 3b, GoR B).
Strong consensus (100 %).
In patients with acute acalculous cholecystitis unfit for surgery, percutaneous ultrasound-guided
gallbladder drainage should be considered after diagnostic puncture (LoE 2c, GoR B).
Strong consensus (100 %).
Drainage route
The transhepatic route has advantages regarding tract formation and the avoiding of
peritonitis [280]
[281]. The transperitoneal approach has been reported to be similar in relation to complications,
but formation of a mature tract without leakage as a precondition for catheter removal
is significantly delayed compared with the transhepatic approach [280]
[282]
[283]. EUS-guided transmural gallbladder drainage may be performed as an alternative to
USPC [192].
Ultrasound-guided percutaneous gallbladder drainage should be performed transhepatically
(LoE 2b, GoR B). Strong consensus (100 %).
Percutaneous gastrostomy
Introduction
Gastrostomy can be offered when oral food uptake is temporarily or permanently compromised.
Gastrostomy may be used in patients with neurological disorders (e. g., neurological
degeneration) and advanced (oncological) diseases, e. g. in gastrointestinal stenosis
with intractable vomiting where surgical treatment is not feasible or is declined.
The endoscopic approach (percutaneous endoscopic gastrostomy, PEG) with the “pull”
technique is the most common technique.
Image-guided percutaneous gastrostomy (without endoscopic access)
The percutaneous approach (image-guided percutaneous gastrostomy, PG) can be performed
under fluoroscopy (radiologically inserted gastrostomy, RIG) or US guidance (USPG).
US guidance in experienced hands allows the identification of the position of (a)
the stomach, (b) the liver, and (c) in most instances, the transverse colon. Usually
the stomach is filled with water by a nasogastric tube, but if US is used to assist
endoscopy, air distension is sufficient.
US may be used in the following situations:
-
In cases of anticipated difficulty locating the stomach (scars, advanced gastric cancer,
obesity, surgically altered stomach anatomy).
-
In endoscopic approach when trans-illumination fails.
-
In cases without access to the upper gastrointestinal tract (complete esophageal obstruction).
In cases in which conventional endoscopically guided gastric puncture fails, ultrasound-assisted
gastric puncture may make it possible to accomplish percutaneous gastrostomy (LoE
4, GoR C). Broad agreement (76 %).
When placing of a nasogastric tube is not possible, the stomach can be punctured under
ultrasound guidance and distended with air or water to facilitate percutaneous image-guided
gastrostomy (LoE 4, GoR C). Broad agreement (86 %).
Antibiotic prophylaxis is mandatory for PEG using the pull technique for prevention
of peristomal infection. For introducer techniques, antibiotic prophylaxis is not
necessary. The database for antibiotic prophylaxis in PEG is comprehensive [284]. There is data for RIG showing no wound infections [285].
Percutaneous nephrostomy
Introduction
Percutaneous nephrostomy (PCN) remains the procedure of choice for temporary drainage
of the obstructed collecting system when the transureteral (or retrograde) approach
is not indicated or feasible [286]
[287]. PCN is also used for urinary diversion and to gain access to the urinary tract
for subsequent interventional urologic procedures. PCN can be successfully performed
in 95 – 98 % of patients who have a dilated renal collecting system [250].
Indications and contraindications
Indications
PCN may be performed for diagnostic or therapeutic purposes [288]
[289].
-
Relief of urinary obstruction related to malignancy, urinary stones or iatrogenic
causes [289].
-
Pyonephrosis and obstructive acute pyelonephritis.
-
Urinary diversion in patients with urinary fistula, leakage or hemorrhagic cystitis
[290]
[291].
-
Access for endourologic procedures, such as nephrolithotomy and removal of urinary
stones, dilation or stenting of a ureteral stricture [288].
-
Diagnostic testing, such as antegrade pyelography, ureteral perfusion (Whitaker test)
[290].
-
Specific situations, e. g., uroenteric diversion.
-
Treatment of urolithiasis in transplanted kidneys and external malignant obstruction
[292]
[293]
[294]
[295].
Contraindications
There is no absolute contraindication for PCN, but the benefits and risks must be
weighed for each individual [288]
[289]. Relative contraindications are:
-
Renal vascular malformations such as an arterial aneurysm [290],
-
Severe life-threatening electrolyte imbalances such as hyperkalemia, or severe metabolic
acidosis [288],
-
Severe coagulopathy [296].
Imaging modalities
The optimal imaging methods to guide PCN vary at individual centers. The procedure
can be performed with the guidance of fluoroscopy, US, CT, and various combinations
of those techniques [297]
[298]
[299].
Ultrasound guidance
US-guided puncture of the collecting system with subsequent placement of the drainage
tube under fluoroscopic control is regarded as the standard technique for PCN [290]
[300]
[301]. US is helpful to identify the most appropriate calyx for puncture and the presence
of stones or blood clots or other intraluminal filling defects and to avoid damage
to surrounding organs [302]. In addition, it is an ideal method for patient follow-up [302].
Percutaneous nephrostomy can be effectively performed under ultrasound guidance (LoE
2b, GoR B). Strong consensus (100 %).
Injection of US contrast agents via a needle or catheter can also confirm whether
the needle or PCN catheter have been correctly inserted in the renal pelvis, with
reduction in radiation exposure which may be especially important in the first trimester
of pregnancy [303]. Fluoroscopy is recommended to determine the position of the needle and guidewire.
The catheter can be visualized by injecting diluted US contrast agent.
Technical aspects and indications
Methods
Positioning
The risk of adjacent organ injury during percutaneous nephrostomy is minimized when
the nephrostomy is inserted below the 12th rib. Attempts should be made to achieve
catheter placement through a calyx, particularly if percutaneous nephrolithotomy or
other large-bore catheter placement is considered [290].
Seldinger or trocar technique
US-guided PCN tube placement has a success rate of 92 – 94 % [304]
[305]. The trocar and Seldinger techniques are equally effective [306].
Size
A 6 – 10F catheter is recommended for PCN. If the collecting system is punctured for
further procedures (e. g., tumor or stone removal), a larger catheter may be considered
(14 – 22F).
In percutaneous nephrostomy, access via the posterior-inferior calyces should be attempted
to reduce the risk of pleural and vascular injury (LoE 5, GoR D). Strong consensus
(100 %).
Post-procedure catheter management and patient care
Vital signs should be monitored during initial recovery (> 24 hours) [288]. Urinary output should be charted. Urine will be blood-tinged initially but prolonged
hematuria (> 24 – 48 hours) should serve as an alert to persistent bleeding from vascular
injury [288]
[307]. Long-term indwelling catheters should be changed every 4 – 6 weeks [250].
Complications
The incidence of major complications ranges from 0 – 8 % [286]
[299]
[308]
[309]. Minor complications occur in 2 – 38 % [286]
[299]
[308]
[309].
Suprapubic puncture of the bladder
Suprapubic puncture of the bladder
Introduction
Suprapubic puncture of the bladder is a safe and reliable method to drain the bladder,
while avoiding urethral catheterization [310]. US guidance improves the success rate [311]
[312]
[313]
[314].
US is recommended to assess the position and volume of the bladder, and to avoid the
inadvertent puncture of other structures [315]
[316].
Puncture and drainage of the urinary bladder should be performed under ultrasound
guidance (LoE 1b, GoR B). Strong consensus (100 %).
Main indications
Suprapubic puncture of the bladder is indicated in pathological conditions of the
bladder, prostate or urethra that require temporary or permanent drainage of the bladder
when urethral catheterization is not possible or is contraindicated.
Contraindications to the percutaneous US-guided procedure
-
Absence of visualization of the bladder on US.
-
Uncorrected coagulopathy.
-
Other relative contraindications are those secondary to complex anatomy due to congenital
disorders, habitus, previous surgery or infiltrative pelvic cancer.
Materials and technical problems
The procedure is performed under sterile conditions after the administration of local
anesthesia. Sedation may be useful in select cases. The position and volume of the
bladder are identified by US and US is used for real-time guidance of the percutaneous
puncture [315]
[316]. Catheters are placed by either the Seldinger or the trocar technique, with dilation
of the percutaneous track when necessary. Catheters of 10F are large enough to relieve
acute urinary retention. Large catheters (> 16F) are recommended in patients who require
prolonged drainage of the bladder in circumstances such as bladder rupture or complicated
urethral stricture [310].
Complications
US guidance can decrease the complication rate of suprapubic puncture [310]
[314]
[317]. Major complications are rare and include perforation of intestinal loops [318]. Minor complications include pain, infection, hemorrhage, blockage, hematuria and
catheter misplacement, all of which are less common when US guidance is performed
[314]
[317]
[319].
Palliative care
Palliative care patients often have alterations in locoregional anatomy, vascular
patterns and coagulation factors. Therefore, for any invasive procedure it is recommended
to consider US guidance to improve safety and help minimize complications and patient
discomfort. There are no contraindications of US-guided procedures in palliative care
[320]. The management of cancer complications indicates potential roles for home-performed
US and US-guided procedures at the end of life [321].