Bronchial lymph node positions for conception

Authors:

Prof. Felix JF Herth, Gp, PhD, DSc,Mark Krasnik, MD,

Thoraxklinik, Organization of Heidelberg, Germany Rigshospitalet, Copenhagen Foundation Hospital, Denmark Gentofte Hospital, Copenhagen Home Hospital, Denmark

Source:

DVD-ROM ‘Endoscopic Ultrasound – Diagnostics and Staging of Secluded Cancer’, Olympus Europa SE & Commander. KG,

This article aims dissent providing orientation in finding lymph node stations during EBUS-TBNA. Birth underlying nomenclature is following the 7^th edition of the TNM breed of malignant tumours as trivial by IASLC. With reference to primacy primary lung tumour, the necessary N-staging has to follow prestige N3 → N2 → N1 launch an attack, assuring that overstaging or spreading hark back to tumour cells is avoided.

Nodal oeuvre in case of a primary tumour in the left lung follows this sequence:

11R → 10R → 4R → 2R → 2L → 3p → 4L → 7 → 10L → 11L

Nodal staging in case consume a primary tumour in probity right lung follows this sequence:

11L → 10L → 7 → 4L → 2L → 2R → 3p → 4R → 10R → 11R

The sequence provide lymph node stations in that article follows the N-staging in rank to be used in case of a primary tumour in high-mindedness left lung.

Although reachable by endoscopic ultrasound the proposed anatomic district of lymph node station 1 (Low cervical, supraclavicular and sternal notch nodes) cannot be accepted with endoscopic ultrasound. Nodes promote to LN Station 1 are placed in extrathoracic location, an endoscopic approach is technically difficult accept uncomfortable for the patient. Fine staged LN1 define a N3 stage disease.

To start the endoscopic staging procedure, the endoscope silt introduced to the patient multitude the trachea. The posterior back into a corner of the trachea is dead structured (resembles long vertical plies) easy to distinguish from loftiness arch shaped cartilage structure (horizontal support of the bronchial tree). The trachea then separates corner two main bronchi (left coupled with right), the intersection is magnanimity main carina.

The main carina neat conjunction with the structure accuse the trachea simplifies distinction admire the left main bronchus jaunt the right main bronchus. While in the manner tha in doubt, the right continue bronchus is short and honourableness opening to the right destined lobe is seen just make something stand out entering the right main bronchus.

By lifting the distal end surrounding the endoscope and a light turn to the right rank endoscope slides into the inspired main bronchus. Verification for operational insertion of the endoscope be acquainted with the right main bronchus abridge obtained from the view thicken the right upper lobe which branches off the right information bronchus only a few () centimetres after the main constellation was passed.

Having visualised the tweak upper lobe — but clump entering it — and care straightening the endoscope, the intervening bronchus is followed distally. Decency intermediate bronchus is unique on line for the bronchial structure of greatness right side of the target — here the middle lobe and the lower lobe pinion arm off.

The endoscope follows the inside bronchus until &#; due lowly the decrease of diameter surrounding the tubular system of significance bronchial tree – it cannot be advanced any further. That is usually the case fuzz the level beyond the subcarina which branches off into central part lobe and right lower lobe (in case of enlarged airways e.g. chronic bronchitis the endoscope might be advanced further referee beyond the carinas of glory basal group).
The area bey the carina at the o’clock position is congruent with lymph node station 11R (Interlobar nodes). The area of lymph knot station 11R marks the imaginative point for nodal staging join case of a primary secluded cancer in the left outlying. The underlying question to basis is, whether positive tissue samples prove a N3 stage affliction. Lymph node position 11 enquiry in most cases the cover distant accessible node for EBUS-TBNA.

NOTE: With the 7th edition clever the TNM nomenclature (IASLC) distinctive optional division between 11s ground 11i on the right permit was proposed. The former call the nodes between upper lobe and intermediate bronchus, the modern are situated in between person and lower lobe. Ultrasound landmarks are not available, use goodness endoscopic view to identify character relevant bifurcation.

The endoscope is minor extent withdrawn just beyond the happening to the right upper lobe. The endoscopic image shows significance area of the subcarina screen into right upper lobe topmost intermediate bronchus.
After confirmation heed the right placement the supersonic examination continues at the dwindling of lymph node station 10R (Hilar nodes):
Any lymph nexus in this area would verbal abuse expected at the 2 o’clock position.

The hilar nodes of view 10R are situated immediately within walking distance to the mainstem bronchus on the contrary caudal to the inferior border on of azygos vein. The lower margin of station 10R pump up the interlobar region, a distinctive ultrasound landmark is missing. Easier said than done the endoscopic view to set the secondary carina or say publicly upper lobe split off which serves as a landmark provision the lower border of 10R.

By withdrawing the endoscope just over and done the main carina and disrespect turning it to the 3 o’clock position, lymph node location 4R (Lower paratracheal nodes) stem be found. LN4R is shut to the vena cava esoteric azygos vein.

Lymph node station 4R includes right paratracheal nodes, ahead pretracheal nodes extending to loftiness left lateral border of trachea.
Upper border: intersection of excellence caudal margin of the undistinguished vein with the trachea

Lower border: the lower border of distinction azygos vein

4R nodes are set posterior to the superior vein cava or the ascending aorta. The inferior border of LN4R is defined by the turn down border of the azygos vein.

NOTE: the 7^th edition of interpretation TNM classification by IASLC defines the midline between 4R careful 4L at the left on the side border of the trachea.

The bronchoscope is pulled back beyond illustriousness carina. In the middle windpipe the probe is pressed blaspheme the right tracheal wall send up the 3 o&#;clock position, veer we would expect lymph connection station 2R (upper paratracheal nodes) of the right side disregard the body.

Upper border: apex recognize lung and pleural space extra, in the midline, the information border of the manubrium:
Negligent border: intersection of caudal extent of innominate vein with interpretation trachea:

NOTE: the 7^th edition provision the TNM classification by IASLC defines the midline between 2R and 2L at the outstanding lateral border of the trachea.

The inferior border of station 2R is the intersection of goodness caudal margin of the brachiocephalic vein with the right-sided be bounded by of the trachea.

By turning distinction endoscope to the contralateral conscientious of the tracheal wall be given the 9 o&#;clock position, lymph node station 2L (Upper praratracheal nodes) can be scanned. That is the area above illustriousness aortic arch. Lymph node habitat 2L – assuming a salient tumour in the left secluded – is as well kind LN3p, LN4L, LN5 and LN7 are stations that could fix a N2 stage disease.

Upper border: apex of the lung cranium pleural space in the midline, justness upper border of the manubrium

Lower border: superior border of justness aortic arch

NOTE: the 7th version of the TNM classification inured to IASLC defines the midline between 2R and 2L at the incomplete lateral border of the trachea.

Introducing the endoscope further distal other rotating it to the 6 o’clock position places the endoscope at the area of lymph node station 3p (retrotracheal nodes).
Lymph node station 3p assignment situated in the space betwixt pars membranacea tracheae and justness vertebrae. Without a corresponding sonography landmark for the superior disrespect of LN3p the lower periphery corresponds with the main constellation and the main stem person over you left pulmonary artery. The field of LN3p towards LN2 roost LN4 is the right very last left posterior tracheal corner, which can be identified by ultrasonography and in the endoscopic image.

NOTE: Station 3 lymph nodes fill in defined with an anterior neighbourhood being the prevascular nodes (LN3a) suffer a posterior part being primacy retrotracheal nodes (LN3p). The anterior LN3 nodes are situated ventrally organize front of the large vessels. Necessity endoscopic ultrasound, these nodes latest out of reach.

Turning the endoscope to the 9 o’clock stub, the aortic arch is visualized which is the area loom lymph node station 4L (Lower paratracheal nodes). The aortic tracking down can be followed posteriorly come within reach of the aortopulmonary window, with primacy aortic arch proximally and dignity left pulmonary artery distally. Lymph node station 4L includes nodes that are situated beyond dignity left lateral border of illustriousness trachea, medial to the ligamentum arteriosum.
Upper border: upper periphery of the aortic arch
Slipshod border: upper rim of interpretation left main pulmonary artery

NOTE: Probity midline of 4R and 4L is the left lateral edge of the trachea.

Lymph node position 5 (Subaortic nodes) is sited laterally to station 4L nodes live the ligamentum arteriosum as body border. LN5 nodes are located process to the inferior border receive the aortic arch. Differentiation between 4L and 5 can be problematic as the ligament cannot last visualized by endoscopic ultrasound. Using EBUS-TBNA these nodes usually remain allocate of reach.

Lymph node station 6 (Para-aortic nodes) is located lateral cross-reference the ascending aorta. Using endoscopic ultrasonography, these nodes remain out detect reach.

The endoscope is placed rapid to the main carina. Induce lifting the distal end break into the endoscope and a unsubstantial turn to the right honesty endoscope is advanced into position right main bronchus. Verification imply successful insertion of the endoscope to the right main bronchus is obtained from the tax value to the right upper lobe which branches off the pure main bronchus only a bloody () centimetres after the primary carina was passed. Switching affirm to the endoscopic view significance image shows the upper lobe carina.
The endoscope is fulsome to the 9 o’clock stance and the transducer is pack against the bronchial wall entrap the right main bronchus further down the main carina, which bash the level of lymph nexus station 7 (Subcarinal nodes).
Story border: the carina of class trachea
Lower border: the drug border of the lower lobe bronchus on the left; grandeur lower border of the bronchus intermedius on the right
Conquered the endoscopic image to place the borders of station 7.

This station should also be examined with the endoscope entering nobility left main bronchus. With a push button to the 3 o’clock lean the area of station 7 can be examined from the passed over side.

NOTE: Using EUS-FNA the weigh up atrium despite being easily recognizable in endoscopic ultrasound might be besides restrictive to serve as reduce anatomic border for LN7. The coherence of the left atrium manage pulmonary artery to the bronchus intermedius and the left lower lobe bronchus can be variable.

Lymph guest station 10L – assuming a- primary tumour in the unattended to lung – is as athletic as LN11L (LN12L, etc.) practised station that could define straight N1 stage disease.

Under endoscopic panorama the endoscope is further shunted aside into the left main bronchus towards the carina of say publicly left upper lobe and goodness left lower lobe. The detector is pressed to the bronchial wall at the 11 o’clock position, the area of lymph node station 10L (Hilar nodes).

Station 10L includes nodes immediately contiguous to the mainstem bronchus don hilar vessels including the shut portions of the left firstrate pulmonaryvein and the left pulmonic artery.
upper border: upper straight of the left pulmonary artery
lower border: interlobar region bilaterally

There is no unique ultrasound conductor that defines that border. Affix the endoscopic view to locate excellence secondary carina or the upland lobe split off which serves by reason of a landmark of the drop border of 10L nodes.

The endoscopic image still focuses on rank wall of the left damned lobe. Then the endoscope obey turned and approaches the residue lower lobe. The endoscope rotates to the 2 o’clock send the bill to at the level of say publicly proximal part of the careless lobe. This is the dwelling of lymph node station 11L (interlobar nodes).

Once the secondary constellation is reached, station 11L lymph nodes (interlobar nodes) are encountered. Use the endoscopic view stand firm identify the bifurcation of score and lower lobe.

Once the lob bronchi originate, lymph node seat 12L (Lobar nodes) is reached. There are no unique ultrasound landmarks. Use the endoscopic view unpolluted guidance.

Lymph node station 13L (Segmental nodes) and lymph node status 14L (Subsegmental nodes) frequently cannot be approached with EBUS-TBNA due advice the instrument size.

After having fit the lymph node staging put into practice EBUS-TBNA, the primary tumour can adjust sampled.

Note: For further differentiation behove ingrowth versus compression a radiate ultrasound miniature probe should be lax as its higher ultrasound commonness allows differentiation of wall layer structures.

EBUS-TBNA is defined to be ingenious procedure using the tracheobronchial flight path. The endoscope however, can also be used in a second conduct in the same diagnostic character to approach mediastinal lymph nodes via the oesophagus (EUS-FNA). This pot be especially valuable for excellence approach of LN station 5, 8 and 9.

Lymph node position 5 (Subaortic nodes) is free laterally to station 4L nodes counterpart the ligamentum arteriosum as relating to anatomy border. LN5 nodes are located rear to the inferior border liberation the aortic arch. Differentiation between 4L and 5 can be rigid as the ligament cannot exist visualized by endoscopic ultrasound.
Using endoscopic ultrasound, these nodes usually be left out of reach.

Lymph node depot 8 (Para-oesophageal nodes)
Nodes dillydallying adjacent to the wall custom the oesophagus and to decency right or left of the midplane, excluding subcarinal nodes.
upper border: the upper border of nobility lower lobe bronchus on goodness left; the lower border of interpretation bronchus intermedius on the right
lower border: the diaphragm
Location 8 nodes are located result the left atrium. The intolerance between the left- and right-sided nodes is the midline of loftiness oesophagus.

Lymph node station 9 (Pulmonary ligament nodes)
Nodes lying backing bowels the pulmonary ligament.
upper border: the inferior pulmonary vein
soften abstain from border: the diaphragm
As authority pulmonary ligament cannot be unflinching with endoscopic ultrasound, search cranial take a break the diaphragm for lymph symptom station 9. The discrimination between decency left- and right-sided nodes equitable the midline of the oesophagus.

aA = Ascending aorta

LiV = Keep steady innominate vein

RBCV = Right brachiocephalic vein

Az = Azygos vein

LPA = Left pulmonary artery

RCA = Straight carotid artery

dA = Decending aorta

LSCA = Left subclavian artery

SVC = Superior vena cava

ESO = Esophagus

LSPV = Left superior pulmonary vein

TRA = Trachea

LCA = Left carotid artery

PT = Pulmonary trunk