Flexible bronchoscopy is a key diagnostic and
therapeutic procedure performed by most pulmonologists.¹
Transbronchial needle aspiration (TBNA) is the only technique that
allows the bronchoscopist to sample tissue from beyond the confines of
the endobronchial tree, such as enlarged lymph nodes, extrinsic
compression, peribronchial disease and certain deep submucosal
lesions.
TBNA is performed to stage lung cancer by
sampling mediastinal nodal stations and to diagnose other causes of
mediastinal adenopathy. It is used to sample endobronchial lesions for
a submucosal process where standard forceps might not obtain adequate
tissue diagnosis.
The year 2007 marked the 25th anniversary of
the first publication of this flexible TBNA technique. Although the
acceptance of the procedure grew slowly, a brief survey of the
literature last year identified more than 30 papers on TBNA from
several continents.
The technique of TBNA for use with the
flexible fiberoptic bronchoscope offers a simpler method by which to
determine the extent of midline lymphatic disease in contrast with
surgical mediastinoscopy. In addition, TBNA is performed as an
outpatient procedure and permits the aspiration of a large number of
lymph node regions that are not accessible by mediastinoscopy or
mediastinotomy. TBNA is superior to mediastinotomy for sampling of the
lymph nodes from the aortopulmonary window, posterior carina and
subcarina.
Historical Perspective
TBNA dates back to 1949. An Argentinean
surgeon named Eduardo Schieppati published his findings on subcarinal
puncture in a review of the Argentine Medical Association. Schieppati
is a well-respected doctor and is known as the “Father of TBNA.” At
about the same time, physicians in Europe were experimenting with TBNA
in diagnosing mediastinal lymphadenopathy. Carinal lymph node
involvement was accepted as a contraindication for surgery by many of
these early pioneers. One team used a Vim Silverman needle to perform
subcarinal lymph node biopsies. These men determined that obtaining
adequate subcarinal lymph node material could be a consideration in
making a diagnosis, determining the extent of disease, and helping to
avoid an unnecessary thoracotomy, particularly in patients who are
poor operative candidates. The technique never progressed, however.
Mediastinoscopy evolved as the principal mediastinal staging
procedure.
A doctor, Ko Pen Wang, and colleagues
reinvented and introduced this technique to North America through the
rigid bronchoscope in the early 1970s and later adapted the technique
for the flexible fiberoptic bronchoscope.
Performing TBNA is not difficult, once the
basic instruction and “tricks” to the methods are understood.
Opportunities for competent instruction have proliferated over the
last several years. A training simulator is now available.
A transbronchial needle used through a
flexible bronchoscope requires the following three essential factors:
- It must be flexible, yet rigid enough to
pass through the flexible fiberoptic bronchoscope and penetrate the
bronchus.
- The needle tip must be protected so it will
not lacerate the channel when it passes through the scope.
- When penetrating the bronchial wall the
needle must not become plugged with a piece of bronchial tissue.
Instruments
A variety of needles have been designed. We
support a complete spectrum of diagnostic efforts, and rely on four
designs. Transbronchial needles are designed to be able to pass
through a flexible fiberoptic bronchoscope and come in a variety of
different styles. The variations can be somewhat confusing.
The Wang retractable disposable needle was the
prototype and remains the standard for comparison for TBNA. The entire
needle apparatus consists of a retractable needle system that is 120
centimeters long. The inner sheath is tipped with a 21-gauge, 13-mm
needle.
The MW (Millrose/Wang) 122 is a single-lumen
22-gauge need that is used for obtaining cytology specimens. This
needle has an unobstructed lumen for optional suction.
The MW 319 is a dual needle. The inner and
outer needles have beveled tips. The outer needle is a 19-gauge 15 mm
and the inner needle is a 21-gauge 3 mm. This needle is used for
obtaining histology specimens and has the largest gauge size for
sampling in the central region of the lung.
The MW 522 peripheral cytology needle is a
single lumen needle and is a 13-mm-long 22 gauge. This needle provides
the best flexibility for a peripheral specimen collection.
The instrument with the best peripheral yield
is the NB 120 (needle-tip cytology brush). Cytology needles are
generally much easier to use than histology needles. It is very
important to have a good assistant who aids the bronchoscopist with
the proper specimen preparation. When learning how to do
transbronchial needle aspiration for the first time it is usually
easier to begin with a lesion and work up to a more difficult
location. An example of an easier site would be large lymph nodes in
the anterior or subcarinal location.
Common characteristics among these needles
include:
- a distal retractable sharp beveled needle,
- a middle flexible catheter,
- a proximal control device that manipulates
the movement of the needle, the stylet, or both,
- and a sideport through which suction can be
applied.
Retractable needles have now replaced the
old-fashioned fixed needles because they prevent damage to the working
channel of the fiberoptic bronchoscope during insertion. The flexible
plastic catheter is usually 2 mm in diameter and 120 cm long and
houses a needle and a flexible stylet. It transmits a negative
pressure from the proximal to the distal end. A stylet provides
rigidity to the needle for successful insertion through the thicker
proximal airway walls.
Technique
Chest radiograph (CXR) and computed tomography
(CT) scans of the chest should be thoroughly reviewed to locate
nodules, masses and mediastinal lymph node involvement before TBNA.
This should help select the proper site for needle puncture. During
routine fiberoptic bronchoscopy, however, if a lesion amenable to TBNA
is encountered, the procedure can be performed without radiograph. A
routine coagulation profile, in the absence of a history of bleeding
or the use of anticoagulants, is not needed.
Fluoroscopic guidance is essential for
sampling peripheral masses but not central tumors. Recent introduction
of ultrasound bronchoscopy (EBUS) has dramatically improved the
diagnostic yield.
Using a transbronchial needle either a
cytology or histology specimen may be obtained. Proper selection of
the needle is of the utmost importance. For cytology, a 21- or
22-gauge needle is used and this provides only a malignant diagnosis.
You use either an 18- or 19-gauge needle (large bore) in order to
obtain a histology specimen. When you obtain a histology specimen you
are able to diagnosis malignant as well as benign diseases. Some
examples of benign diseases that might be diagnosed are sarcoidosis,
histoplasmosis and tuberculosis.
To obtain a specimen for cytological
examination, the needle is introduced through the working channel with
the tip concealed within the metal hub. The fiberoptic bronchoscope is
kept as straight as possible, with its distal tip in the neutral
position. These steps are extremely important in order to prevent
damage to the working channel of the fiberoptic bronchoscope. Once the
metal hub is visible from the distal end of the fiberoptic
bronchoscope, the needle is advanced and then locked into place. The
catheter is retracted until only the tip of the needle is visible. The
scope is advanced to the target area, and the tip of the needle is
anchored into the intercartilaginous space. At this stage, the goal is
to penetrate the tracheobronchial wall as perpendicularly as possible.
The needle can be inserted through the
bronchial wall through the following techniques:
Jabbing method
The needle is thrust through the
intercartilaginous space with a quick, firm jab to the catheter while
the scope is fixed at the nose or the mouth.
Pushing method
Once the needle is advanced and locked into
position, the catheter is fixed against the proximal end of the
insertion port using the index finger in a single port scope or the
little finger in a dual port scope to prevent recoil when resistance
met. The bronchoscope and catheter are then pushed forward as a single
unit until the entire needle penetrates the tracheobronchial wall.
Cough method
The jabbing or pushing technique is applied
while the patient coughs to facilitate spontaneous penetration of the
needle.
Hub against the wall method
Occasionally, with the needle retracted, the
distal end of the catheter (the metal hub) can be placed directly in
contact with the target and held firmly while the needle is pushed
through the tracheobronchial wall. All of these techniques can be used
singly or in combination to insert the needle through the
tracheobronchial wall.²
Indications and Results
At University of Maryland Medical Center, a
cytotechnologist is present for the key portion of the bronchoscopic
examination when transbronchial needle aspirations are done. The
cytotechnologist will prepare the bronchial brushing slides as well as
the transbronchial needle aspiration slides. The cytopathologist will
use a diff-quick stain to confirm the adequacy of the diagnostic
material obtained.
Diagnostic yield is determined primarily by
the ability to reach the lesion and the nature of the abnormality. The
diagnostic yield is also increased for transbronchial needle
aspiration with proper and immediate preparation of the specimen.
Nondiagnostic histology specimens usually demonstrate a normal lymph
node with some lymphocytes.
When performing TBNA to stage lung cancer, the
potential for a false-positive result caused by contamination with
bronchial secretions can be minimized by performing TBNA before any
washing, brushing, or biopsy specimens are obtained. Despite the
extensive use of TBNA, false-positive rates have been low.
A number of positive specimens usually contain
a large number of tumor cells in form of clumps or in glandular
formation with a large number of lymphocytes and without any
respiratory epithelial cells. A specimen is not considered positive in
the presence of few malignant cells and with a large number of
respiratory epithelial cells.
Overall, transbronchial needle aspiration can
preclude the need for staging surgery in one half of the patients
whose tumors are unresectable because of mediastinal invasion.
Complications
The incidence of complication is low. The most
frequent is pneumothorax (with the incidence of less than 1 percent).
One rare complication that can occur is a hemomediastinum. Serious
bleeding is seldom encountered. More commonly, inadvertent passage of
an exposed needle through the wall of the working channel of the
flexible fiberoptic bronchoscope and leads to very extensive damage to
the inner lining of the bronchoscope.
When using the 18-gauge transbronchial needle
the patient could feel discomfort during insertion. Symptoms are
varied and might include pressure in the substernal area, discomfort
to the nose and /or the back of the throat, and coughing throughout
the procedure.
Conclusions
Flexible transbronchial needle aspiration
provides a bronchoscopic method for the diagnosis and staging of lung
cancer. Increasing experience has confirmed the usefulness of this
procedure and has identified several technical factors that influence
its yield and safety.
The complication rate for TBNA is extremely
low. TBNA usually produces less bleeding than does transbronchial
forceps biopsy. TBNA is a safe procedure that can increase the
diagnostic yield of the flexible fiberoptic bronchoscopy.
It is a safe and useful and economical
technique that can be used in diagnosing and staging patients with
cancer of the lung. If the transbronchial needle aspiration is
negative a mediastinoscopy is then done. Flexible fiberoptic
bronchoscopy with transbronchial needle aspiration can reduce the need
for mediastinoscopy by nearly 50 percent. Hopefully, this technique
will further reduce the need for more invasive surgical procedures in
the future.
With time, it is expected that more and more
pulmonologists will attain expertise with TBNA and the full potential
of this cost-effective and safe non-surgical procedure will be
realized.³
As healthcare expenses continue to soar, more
emphasis must be placed on efforts to shorten hospitalization time and
minimize the cost of medical care. Transbronchial needle aspiration
could one day surpass surgical mediastinal exploration as the initial
staging procedure of choice, thus saving several millions of dollars
in the United States healthcare system.
Sharon Lesser, RN, is a pulmonary clinical
nurse in the department of pulmonary and critical care medicine at the
University of Maryland Hospital in Baltimore.
Note: Lesser thanks her boss, E.J. Britt, MD,
for his assistance with this paper.
References
1. Tape TG, Blank LL, Wigton RS. Procedural
skills of practicing pulmonologists: a national survey of 1,000
members of the American college of Physicians. Am J Respir
Crit Care Med 1995; 151:282–287.
2. Bolliger, C.T., Mathur, P.N.,
Interventional Bronchoscopy, S. Karger AG, Switzerland 2000, pg 69-70.
3. Bolliger, C.T., Mathur, P.N.,
Interventional Bronchoscopy, S. Karger AG, Switzerland 2000, pg 77.
