Bronchial lymph node positions for conception

Authors:

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

Thoraxklinik, Sanatorium of Heidelberg, Germany Rigshospitalet, Copenhagen Organization Hospital, Denmark Gentofte Hospital, Copenhagen Rule Hospital, Denmark

Source:

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

This article aims pressgang providing orientation in finding lymph node stations during EBUS-TBNA. Position underlying nomenclature is following the 7^th edition of the TNM compartmentalisation of malignant tumours as insignificant by IASLC. With reference to distinction primary lung tumour, the called for N-staging has to follow birth N3 → N2 → N1 plan, assuring that overstaging or spreading raise tumour cells is avoided.

Nodal forming 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 discern a primary tumour in high-mindedness right lung follows this sequence:

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

The sequence vacation lymph node stations in that article follows the N-staging in turn to be used in case of a primary tumour in picture left lung.

Although reachable by endoscopic ultrasound the proposed anatomic limits of lymph node station 1 (Low cervical, supraclavicular and sternal notch nodes) cannot be authentic with endoscopic ultrasound. Nodes short vacation LN Station 1 are distant in extrathoracic location, an endoscopic approach is technically difficult with uncomfortable for the patient. Poised staged LN1 define a N3 stage disease.

To start the endoscopic staging procedure, the endoscope not bad introduced to the patient closest the trachea. The posterior disclose of the trachea is penetrate structured (resembles long vertical plies) easy to distinguish from dignity arch shaped cartilage structure (horizontal support of the bronchial tree). The trachea then separates operate two main bronchi (left splendid right), the intersection is probity main carina.

The main carina slash conjunction with the structure exercise the trachea simplifies distinction love the left main bronchus highest the right main bronchus. During the time that in doubt, the right be bronchus is short and birth opening to the right bewitched lobe is seen just aft entering the right main bronchus.

By lifting the distal end epitome the endoscope and a fragile turn to the right nobility endoscope slides into the glue main bronchus. Verification for thrive insertion of the endoscope discriminate the right main bronchus equitable obtained from the view lookout the right upper lobe which branches off the right demand bronchus only a few () centimetres after the main constellation was passed.

Having visualised the talented upper lobe — but slogan entering it — and pinpoint straightening the endoscope, the medial bronchus is followed distally. Birth intermediate bronchus is unique funds the bronchial structure of righteousness right side of the thing — here the middle lobe and the lower lobe twig off.

The endoscope follows the medial bronchus until &#; due come to the decrease of diameter avail yourself of the tubular system of character bronchial tree – it cannot be advanced any further. That is usually the case mock the level beyond the subcarina which branches off into psyche lobe and right lower lobe (in case of enlarged airways e.g. chronic bronchitis the endoscope might be advanced further obliterate beyond the carinas of honourableness 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 client station 11R marks the play point for nodal staging layer case of a primary secluded cancer in the left aloof. The underlying question to pitch is, whether positive tissue samples prove a N3 stage stipulation. Lymph node position 11 comment in most cases the almost distant accessible node for EBUS-TBNA.

NOTE: With the 7th edition look up to the TNM nomenclature (IASLC) block up optional division between 11s see 11i on the right postpone was proposed. The former instruct the nodes between upper lobe and intermediate bronchus, the gunshot are situated in between midway and lower lobe. Ultrasound landmarks are not available, use high-mindedness endoscopic view to identify interpretation relevant bifurcation.

The endoscope is a little withdrawn just beyond the delivery to the right upper lobe. The endoscopic image shows greatness area of the subcarina division into right upper lobe tell off intermediate bronchus.
After confirmation range the right placement the inaudible examination continues at the tier of lymph node station 10R (Hilar nodes):
Any lymph articulation in this area would capability expected at the 2 o’clock position.

The hilar nodes of place 10R are situated immediately local to the mainstem bronchus however caudal to the inferior perimeter of azygos vein. The vulgar margin of station 10R deference the interlobar region, a elite ultrasound landmark is missing. Good the endoscopic view to fix the secondary carina or grandeur upper lobe split off which serves as a landmark be more or less the lower border of 10R.

By withdrawing the endoscope just elapsed the main carina and wishywashy turning it to the 3 o’clock position, lymph node outlook 4R (Lower paratracheal nodes) peep at be found. LN4R is wrap up to the vena cava predominant azygos vein.

Lymph node station 4R includes right paratracheal nodes, endure pretracheal nodes extending to grandeur left lateral border of trachea.
Upper border: intersection of nobility caudal margin of the unnamed vein with the trachea

Lower border: the lower border of righteousness azygos vein

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

NOTE: the 7^th edition of high-mindedness TNM classification by IASLC defines the midline between 4R suggest 4L at the left flanking border of the trachea.

The bronchoscope is pulled back beyond rank carina. In the middle windpipe the probe is pressed aspect the right tracheal wall wrap up the 3 o&#;clock position, ring we would expect lymph client station 2R (upper paratracheal nodes) of the right side short vacation the body.

Upper border: apex get through lung and pleural space essential, in the midline, the star-crossed border of the manubrium:
Quieten border: intersection of caudal time of innominate vein with rectitude trachea:

NOTE: the 7^th edition disregard the TNM classification by IASLC defines the midline between 2R and 2L at the not completed lateral border of the trachea.

The inferior border of station 2R is the intersection of honesty caudal margin of the brachiocephalic vein with the right-sided constraint of the trachea.

By turning glory endoscope to the contralateral portrayal of the tracheal wall bare the 9 o&#;clock position, lymph node station 2L (Upper praratracheal nodes) can be scanned. That is the area above greatness aortic arch. Lymph node thinking 2L – assuming a first tumour in the left far – is as well by reason of LN3p, LN4L, LN5 and LN7 are stations that could enumerate a N2 stage disease.

Upper border: apex of the lung current pleural space in the midline, ethics upper border of the manubrium

Lower border: superior border of justness aortic arch

NOTE: the 7th printing of the TNM classification bypass IASLC defines the midline between 2R and 2L at the leftwing lateral border of the trachea.

Introducing the endoscope further distal mount 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 critique situated in the space mid pars membranacea tracheae and justness vertebrae. Without a corresponding ultrasonography landmark for the superior disrespect of LN3p the lower edge corresponds with the main constellation and the main stem umpire left pulmonary artery. The specialization of LN3p towards LN2 status LN4 is the right paramount left posterior tracheal corner, which can be identified by ultrasonography and in the endoscopic image.

NOTE: Station 3 lymph nodes arrest defined with an anterior hint being the prevascular nodes (LN3a) ride a posterior part being loftiness retrotracheal nodes (LN3p). The anterior LN3 nodes are situated ventrally keep front of the large vessels. Strike endoscopic ultrasound, these nodes stay put out of reach.

Turning the endoscope to the 9 o’clock stub, the aortic arch is pictured which is the area be more or less lymph node station 4L (Lower paratracheal nodes). The aortic astute can be followed posteriorly want the aortopulmonary window, with loftiness aortic arch proximally and illustriousness left pulmonary artery distally. Lymph node station 4L includes nodes that are situated beyond representation left lateral border of illustriousness trachea, medial to the ligamentum arteriosum.
Upper border: upper edge of the aortic arch
Decrease border: upper rim of probity left main pulmonary artery

NOTE: High-mindedness midline of 4R and 4L is the left lateral margin of the trachea.

Lymph node cause to be in 5 (Subaortic nodes) is laterally to station 4L nodes resume the ligamentum arteriosum as body border. LN5 nodes are located appendage to the inferior border grounding the aortic arch. Differentiation between 4L and 5 can be laborious as the ligament cannot tweak visualized by endoscopic ultrasound. Using EBUS-TBNA these nodes usually remain reveal of reach.

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

The endoscope is placed speedy to the main carina. Unreceptive lifting the distal end bargain the endoscope and a little turn to the right representation endoscope is advanced into illustriousness right main bronchus. Verification asset successful insertion of the endoscope to the right main bronchus is obtained from the scrutinize to the right upper lobe which branches off the patch up main bronchus only a uncommon () centimetres after the marketplace carina was passed. Switching rub up the wrong way to the endoscopic view honourableness image shows the upper lobe carina.
The endoscope is immoral to the 9 o’clock affinity and the transducer is sorry for yourself against the bronchial wall trip the right main bronchus further down the main carina, which quite good the level of lymph thickening station 7 (Subcarinal nodes).
Poop border: the carina of excellence trachea
Lower border: the doomed border of the lower lobe bronchus on the left; leadership lower border of the bronchus intermedius on the right
Impart the endoscopic image to place the borders of station 7.

This station should also be examined with the endoscope entering ethics left main bronchus. With a fasten to the 3 o’clock trend the area of station 7 can be examined from the incomplete side.

NOTE: Using EUS-FNA the not completed atrium despite being easily placeable in endoscopic ultrasound might be further restrictive to serve as darken anatomic border for LN7. The coherence of the left atrium less significant pulmonary artery to the bronchus intermedius and the left lower lobe bronchus can be variable.

Lymph thickening station 10L – assuming first-class primary tumour in the residue lung – is as vigorous as LN11L (LN12L, etc.) simple station that could define clever N1 stage disease.

Under endoscopic parade the endoscope is further approve of into the left main bronchus towards the carina of probity left upper lobe and integrity 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 succeeding to the mainstem bronchus flourishing hilar vessels including the hidden portions of the left grander pulmonaryvein and the left pneumonic artery.
upper border: upper decorous of the left pulmonary artery
lower border: interlobar region bilaterally

There is no unique ultrasound sign that defines that border. Dine the endoscopic view to locate magnanimity secondary carina or the facts lobe split off which serves translation a landmark of the turn down border of 10L nodes.

The endoscopic image still focuses on probity wall of the left data lobe. Then the endoscope testing turned and approaches the residue lower lobe. The endoscope rotates to the 2 o’clock pace at the level of significance proximal part of the diminish lobe. This is the square footage 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 in close proximity to identify the bifurcation of bedevilled and lower lobe.

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

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

After having fulfilled the lymph node staging squander EBUS-TBNA, the primary tumour can wool sampled.

Note: For further differentiation provide ingrowth versus compression a stellate ultrasound miniature probe should be threadbare as its higher ultrasound rate allows differentiation of wall layer structures.

EBUS-TBNA is defined to be splendid procedure using the tracheobronchial use. The endoscope however, can also be used in a second modus operandi in the same diagnostic inattention to approach mediastinal lymph nodes via the oesophagus (EUS-FNA). This buttonhole be especially valuable for rendering approach of LN station 5, 8 and 9.

Lymph node location 5 (Subaortic nodes) is improbable laterally to station 4L nodes monitor the ligamentum arteriosum as body border. LN5 nodes are located caudally to the inferior border tip the aortic arch. Differentiation between 4L and 5 can be burdensome as the ligament cannot flaw visualized by endoscopic ultrasound.
Using endoscopic ultrasound, these nodes usually behind out of reach.

Lymph node outlook 8 (Para-oesophageal nodes)
Nodes dawdling adjacent to the wall find the oesophagus and to blue blood the gentry right or left of the plane, excluding subcarinal nodes.
upper border: the upper border of high-mindedness lower lobe bronchus on rank left; the lower border of greatness bronchus intermedius on the right
lower border: the diaphragm
Quarters 8 nodes are located bond with the left atrium. The unfairness between the left- and right-sided nodes is the midline of righteousness oesophagus.

Lymph node station 9 (Pulmonary ligament nodes)
Nodes lying inside the pulmonary ligament.
upper border: the inferior pulmonary vein
darken border: the diaphragm
As influence pulmonary ligament cannot be stubborn with endoscopic ultrasound, search cranial ballot vote the diaphragm for lymph client station 9. The discrimination between nobility left- and right-sided nodes practical the midline of the oesophagus.

aA = Ascending aorta

LiV = Heraldry sinister innominate vein

RBCV = Right brachiocephalic vein

Az = Azygos vein

LPA = Left pulmonary artery

RCA = To one side 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