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274 Resection of posterior mediastinal masses
https://t.me/med1917
POSTOPERATIVE CARE
The typical hospital stay is 1–2 days after a VATS resection
and 4 days after a thoracotomy, and the usual postoperative
course is smooth and uncomplicated. Following resection of
tumors in the costovertebral sulcus, patients undergo regular
neurological examinations of the lower extremities so that the
rare occurrence of a compressing spinal hematoma would be
rapidly identified and relieved. The chest tube in these
patients is removed on the first postoperative day if the volume of drainage is low.
High output of clear or serosanguinous fluid would raise
the suspicion of a CSF leak. This suspicion, if the diagnosis is
not clear, can be confirmed by documenting beta-2 transferrin in the fluid – this protein is present in CSF but not pleural
fluid. The presence of a CSF leak mandates reoperation by a
neurosurgeon; the leak is repaired and generally buttressed
with vascularized tissue.
Following resection of esophageal leiomyomata and duplication cysts, a contrast esophagogram is obtained on postoperative day 1. If this study shows no leak, the patient’s diet is
advanced, and the chest tube is removed.
leiomyoma near the gastroesophageal junction that proved to
be multilobulated and far more extensive than anticipated
from preoperative studies, wrapping itself around the esophagus in a horseshoe fashion. It must be emphasized, however,
that absolutely no hesitation should exist to convert a VATS
procedure to thoracotomy if required.
The principles described above have allowed these cases to
be performed without a complicating CSF leak, spinal
hematoma, or esophageal leak. One patient with a schwannoma did suffer persistent, painful dysesthesia postoperatively in the dermatome of the resected nerve. In no case
where a portion of a bronchogenic or esophageal duplication
cyst wall was left intact has there been a known recurrence.
Further, following resection of leiomyomata or duplication
cysts, we have not identified any diverticula at the surgical site
despite leaving the muscularis incision open. It must be
admitted, however, in presenting these results, that the
patients are followed only by history, physical examination,
and chest radiogram, not by chest CT. It should be mentioned, also, that isolated case reports of recurrences following incomplete cyst wall excision have been published, so
complete excision must remain the goal when possible, until
studies with longer follow-up are published.
OUTCOME
The author’s experience includes 23 posterior mediastinal
masses removed by the VATS approaches described herein.
Primary thoracotomy was employed for several larger or
invasive masses during the same time period, but in only one
case did a procedure begun thoracoscopically require conversion to a thoracotomy. This case involved an esophageal
FURTHER READING
Demmy TL, Krasna MJ, Detterbeck FC, Kline GG, Kohman LJ, DeCamp
MM Jr, Wain JC. Multicenter VATS experience with mediastinal
tumors. Annals of Thoracic Surgery 1998; 66: 187–92.
Vallieres E, Findlay JM, Fraser RE. Combined microneurosurgical and
thoracoscopic removal of neurogenic dumbbell tumors. Annals of
Thoracic Surgery 1995; 59: 469–72.
Lung transplantation
https://t.me/med1917
JOHN DARK
Professor, Regional Cardiothoracic Centre, Freeman Hospital, Newcastle upon Tyne, UK
26
HISTORY
Clinical success in isolated lung transplantation was first
achieved by Cooper and the Toronto group in 1983. They
built on three decades of laboratory work through which had
evolved most of the technical steps, for instance the need for
cuff for the venous anastomosis and various approaches to
bronchial healing.
PRINCIPLES AND JUSTIFICATION
Indications were clearly defined; initially restrictive or fibrotic
disease, expanding to include obstructive (principally
emphysematous) conditions after 1988. Emphysema is now
the commonest pretransplant diagnosis. In the early 1990s
the single lung option was not used, particularly in the USA,
for patients with pulmonary hypertension.
Recipients with septic lung disease require removal of all
the infected tissues – invariably both lungs. This goal was initially achieved with combined heart–lung transplantation,
but such patients received an unnecessary cardiac graft.
However, once safe techniques for bronchial anastomoses
had evolved, the advantage of the very reliable tracheal healing in the heart–lung operation evaporated.
The first alternative approach was the en bloc double lung
transplantation. Considerable morbidity, including the need
for cardiopulmonary bypass and cardioplegic arrest, the
extensive mediastinal dissection, and a 20% tracheal dehiscence rate prevented widespread popularity. Placing the
bronchial anastomoses close to the lung parenchyma, and
performing all of the vascular suture lines at the hilar rather
than the mediastinal level, was the approach originally
described by Pasque and colleagues from St Louis and is the
basis of our standard bilateral lung transplantation. In the
original description a bilateral anterior thoracotomy, linking
across the sternum (the clam shell incision), was an essential
part, giving excellent access to the pleural space often obliterated by dense vascular adhesions. Subsequently, access
through a sternotomy or limited bilateral anterior thoracotomies, keeping the sternum intact, have both been
described, particularly for patients with obstructive as
opposed to septic lung disease.
For the very earliest lung transplantations, the donor was
taken to an operating room adjacent to the recipient; distant
procurement was described in the late 1980s. A fairly standard approach has evolved; the lung and heart are simultaneously flushed in situ with a cold crystalloid preservation
solution. The heart and then the lungs may be extracted separately, or (the norm in Europe) as a single block and then
separated. The tissue can safely be preserved for 6–8 hours
using current techniques although a 10–20% primary organ
dysfunction rate remains.
PREOPERATIVE ASSESSMENT AND
PREPARATION
Donor lung procurement
Less than 20% of solid organ donors yield usable lungs. In
addition to damage from trauma, aspiration, and ventilatorrelated infection, brainstem death itself may precipitate lung
injury. A combination of hydrostatic stress and inflammatory
activation result in endothelial damage and increased alveolar
permeability. “Neurogenic pulmonary edema” is the most
extreme form, but a degree of injury, with some features of
early stages of adult respiratory distress syndrome (ARDS), is
probably present in every donor lung. The decision about
suitability for donation is based on assessment of the chest X-
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ray, the arterial blood gases, the findings at bronchoscopy,
and finally the texture and appearances of the lungs themselves. Areas of actelectasis that re-expand, patchy contusion,
and purulent endobronchial secretions (in the absence of an
inflamed mycosis) are not of themselves contraindications to
use of the lungs. The presence of extensive consolidated areas
that will not re-aerate or the appearance of airway inflammation that might be associated with established infection or significant aspiration, suggest that the lung is not useful. The
function of each lung can be assessed separately by measuring
blood gas samples taken directly from the pulmonary veins.
This technique may identify a perfectly usable single lung in
situations where one lung has poor function; and as a result,
arterial blood gases are misleadingly poor.
OPERATION
Donor lung procurement
If not already done by the team retrieving the intra-abdominal organs, the chest is opened via a median sternotomy. The
heart is exposed and examined, and then both pleurae are
incised just behind the sternum. The pleural spaces are
explored and all lobes of the lungs examined. Posterobasal
segments are often atelectatic and should be re-expanded by a
combination of bronchoscopy and vigorous hand-bagging
via the endotracheal tube.
After heparinization, a standard cardioplegia cannula is
placed in the ascending aorta, and a 14-mm bullet-tipped
cannula in the proximal main pulmonary artery. The brachiocephalic vein is ligated and divided, thus allowing access
through the posterior pericardial reflections to the lower trachea. This tissue should be separated off the esophagus and
encircled by a nylon tape.
To initiate organ retrieval, the superior vena
1
cava (SVC) is doubly ligated just below the
azygos vein and the inferior vena cava (IVC) clamped
intrapericardially. Cardioplegia delivery is begun,
and this step should satisfactorily drain out of the
divided IVC. Inflow of lung preservation solution is
begun while the main pulmonary artery is palpated
to ensure that high pressure is not generated. The tip
of the left atrial appendage should be removed so as
to allow a generous orifice for drainage of the pulmonary effluent. Ventilation of the lungs continues
during this phase, but both pleural cavities are
flooded with ice-cold saline. Care should be taken to
avoid overdistension of either side of the heart. This
problem can easily occur on the left if the drainage
via the left atrial appendage is impeded.
Toward the end of pulmonary flushing, the effluent should run almost clear. It may be more convenient to remove the heart at this stage, and this
maneuver certainly shortens the overall ischemic
time for that organ. The aorta is divided just proximal to the clamp and dissected off the right pulmonary artery. The main pulmonary artery can then
be divided, opening up the transverse sinus. The SVC
is divided and again dissected off the right pulmonary artery. At this stage, only the left atrium connects the heart to the lungs.
1
An incision is made on the left-hand side, midway
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2
between the origin of the pulmonary veins and the atrioventricular groove and well posterior to the base of the left
atrial appendage. This incision is extended over the roof of
the left atrium (i.e. the floor of the transfer sinus), again skirting well to the posterior aspect of the left atrial appendage and
running around to behind the SVC. Inferiorly, the incision is
continued parallel with the coronary sinus until only a strip of
tissue running adjacent to the intra-atrial septum is left connecting the heart to the lungs. This strip is carefully divided,
taking care not to buttonhole the intra-atrial septum. In practice, a thin ribbon of tissue is left attached to the lungs, and
the heart can be removed intact.
Operation 277
Stopping ventilation at this stage is reasonable, but the
endotracheal tube should be left in place. The pericardium is
incised vertically on both sides parallel to and just above the
diaphragm, a dissection that leads backwards towards the
inferior pulmonary ligaments. These tissues can easily be
divided under direct vision, and then the two pericardial incisions are joined inferiorly. An obvious plane exists immediately in front of the esophagus and is revealed with division of
the inferior ligaments; dissection continues up this plane. The
2
scissors are used to divide the pleural reflexions on each side.
On the right, this dissection comes up behind the main
bronchus and is then brought in front of the azygos vein,
eventually linking up with the tape around the trachea. On
the left, dissection is taken up at the level of the aortic arch
which may often be included with the lung block, dividing the
arch branches superiorly and again linking up with the tape
around the trachea.
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At this stage the anesthetist should be instructed
3
to reinflate the lungs to approximately three
quarters of total lung capacity; a stapling instrument
is placed around the trachea which is now the only
structure holding the lung block into the chest. The
endotracheal tube is pulled back a little and the trachea stapled. The trachea is divided above the staple
line and the donor lung block removed from the
chest.
Splitting of the donor lung block
If bilateral lung transplantation is to be performed, the donor
lung block can be transported, inflated and wrapped in
appropriately sealed sterile bags containing lung preservation
fluid, to the recipient. If two separate single lung recipients in
different institutions are to be transplanted, the block must
be split at the donor hospital.
The wall of the left atrium is divided in the midline thus
generating two separate donor atrial cuffs. Prior to this step,
the pulmonary artery can be divided in the line of its bifurcation. An ample amount of pulmonary artery is always present. The posterior part of the pericardium is now divided
from below with an incision which leads up towards the tracheal bifurcation. Care is taken to stay away from the origin
of the right main bronchus, and the proximal left main
bronchus is isolated. Two stapling devices are then used to
divide the proximal left main bronchus such that the trachea
remains attached to the right main bronchus. With division
of the left bronchus, the two lungs can be completely separated, packaged, and dispatched to their recipients.
3
PREOPERATIVE ASSESSMENT AND
PREPARATION
Single lung transplantation
The majority of candidates will have end-stage respiratory
disease as a result of either emphysema (smoking induced or
subsequent alpha 1 antitrypsin deficiency) or pulmonary
fibrosis. The timing of referral for transplantation, as well as
the investigation of the individual condition, has been well set
out in the international consensus document.
Potential candidates must be thoroughly screened to
exclude other organ dysfunction, particularly cardiovascular
and renal. Patients with obstructive lung disease, who often
have a history of heavy cigarette consumption, should be
appropriately screened for cardiovascular disease. Left ventricular function must be normal, and any coronary disease
should be dealt with by appropriate angioplasty and stenting.
Before acceptance, suitable recipients should have shown at
least the potential for rehabilitation. Bed-bound or moribund
patients are no longer accepted for lung transplantation.
Operation 279
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Lung perfusion scanning is used to identify the “worse”
lung, and this lung will usually be the side selected for transplantation. On the other hand, a site of any extensive previous
surgery, for instance pleurodesis, should be avoided. Many
patients with fibrotic disease may have had an open or videoassisted thoracoscopy (VAT) lung biopsy. This procedure is
of little or no consequence and can be ignored when selecting
the site for surgery.
ANESTHESIA
Single lung transplantations, other than those done for pulmonary hypertension, do not usually require cardiopulmonary bypass. The first essential is reliable one-lung
ventilation with a double-lumen endotracheal tube placed to
the contralateral side. Standard monitoring includes a radial
artery line for blood pressure and blood gas estimation
together with central venous access. Continuous monitoring
of end-tidal CO2should be regarded as essential. Additional
measurements, in the form of a pulmonary artery catheter or
transesophageal echo for the observation of right ventricular
function, may be helpful in borderline patients. We have
found that simple measures, in particular blood gases, safely
predict patients who will require cardiopulmonary bypass.
No advantage is obtained in struggling with an acidotic,
hypoxic, or hypotensive patient merely for the sake of avoiding bypass. We, and others, have shown that the use of bypass
does not disadvantage the patient.
The hemodynamic behavior during one-lung ventilation is
determined by the underlying pathology. In restrictive disease, oxygenation can usually be maintained, but very high
inflation pressures are required for adequate minute ventilation, and an inexorable rise in arterial or end-tidal P
occur. This problem, or hypotension during trial pulmonary
artery (PA) clamping (see below), indicates right ventricle
(RV) embarrassment and the need for bypass. On the other
hand, those patients with restrictive disease can almost always
be managed conservatively as long as the effects of air trapping or the occasional occult contralateral pneumothorax are
detected and dealt with appropriately.
The problems, and solutions, are similar for the patient
undergoing bilateral lung transplantation. Monitoring of the
patient is as for a single lung transplantation. A left-sided
double-lumen tube is placed – only rarely does it interfere
with the left bronchial anastomosis. If the situation is such
that bypass would inevitably be required, i.e. in a pulmonary
CO
2
may
hypertensive patient, or where it is local habit, only a singlelumen tube is required.
Bronchial toilet is essential for the patient with septic lung
disease; loss of function of a segment or lobe because of failure to clear secretions and maintain ventilation may precipitate major problems in borderline patients. The most difficult
periods are: (i) after the completion of the removal of the first
lung; (ii) then during the second pneumonectomy; and (iii)
when the patient is entirely dependent upon the newly
implanted and recently reperfused transplant lung. Function
of this first lung is often precarious as it is literally squeezed
between the vigorous right ventricle often found in these
patients and intermittent elevations of left atrial pressure as
access to the posterior part of the hilum is sought. In this situation and analogous to the patient undergoing single lung
transplantation, avoiding cardiopulmonary bypass at the cost
of a compromised recipient circulation is not wise.
Primary lung dysfunction occurs in up to 20% of recipients
and is manifest by a noncardiogenic pulmonary edema,
often with proteinaceous fluid appearing in the airway.
Management is supportive although inhaled nitric oxide
(20–30 parts/million) appears to have had a considerable
impact on the management of these patients.
OPERATION
Single lung transplantation
After induction of anesthesia, and in particular the demonstration of reliable one-lung ventilation, the patient is placed
in the fully lateral position. The chest is opened through a
standard thoracotomy along the upper border of the sixth rib.
Patients with fibrotic disease have a shrunken chest, and the
surgeon should be aware of entering the pleura an interspace
too low. This problem greatly increases the difficulties of
what is already an awkward operation.
Intrapleural adhesions are unusual and can be easily dealt
with. The anesthetist is instructed to deflate the nonoperated
lung whilst the hilar structures are identified. A tape should
be passed around the pulmonary artery at an early stage. Even
in the most stable patient, the PA should be clamped for a
trial period of 10–15 minutes to ensure that ventilation and
perfusion of the dependent lung only can be tolerated. This
situation will be the case for almost all patients with obstructive disease and for the majority with restrictive physiology,
although maintaining their stability is always a challenge to
the anesthetist.
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A straightforward pneumonectomy is then
4a,b
monary artery branches first to avoid at this stage having a
clamp in the operative field. Similarly the pulmonary veins
are ligated and divided outside the pericardial cavity, and the
inferior pulmonary ligament is divided with cautery, staying
clear of the vagus nerve. On the right, the phrenic nerve runs
close to the hilar structures, and damage must be avoided at
all costs. The bronchus is simply divided at the level of this
first branch and any bleeding bronchial artery controlled
with metal clips. By dividing the bronchus so far distally, the
vagus nerve can be protected.
performed. Our habit is to ligate and divide pul-
4a
4b
Operation 281
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PREPARATION OF THE HILUM
The pulmonary artery is mobilized off adjacent structures,
particularly the bronchus, in order to produce a length suitable for subsequent clamping. On the right, the dissection is
carried under the SVC. On the left, it is rarely necessary to
divide the ligamentum; and indeed, the area around the
recurrent laryngeal nerve can be avoided.
The pericardium is opened in front of the pulmonary veins
which are then mobilized completely off the pericardial
reflexions. This maneuver may be awkward posteriorly, but it
is important to stay within the pericardium and not to
develop the plane between the bronchus and the pericardium
which may threaten the blood supply to the recipient’s
bronchial stump. The complete mobilization of the pulmonary veins is important to allow comfortable placement of
a side-biting clamp. Finally, the bronchus is trimmed back so
that it is flush with the mediastinal tissues and in particular is
not devascularized. 4/0 polypropylene sutures are placed at
each junction of the membranous and cartilaginous portions
of the bronchus.
In the donor lung, the vascular structures are prepared,
and the bronchus is trimmed with a knife as close as possible
to the origin of the first (upper lobe) branch. Peribronchial
tissues are preserved, so as not to disturb the blood supply
from pulmonary to bronchial collaterals. The lung is placed
in the posterior part of the chest (i.e. the costo-vertebral
angle). The emphysematous patient with very large total lung
capacity has a great deal of room, and the access is straightforward. In the small chest cavity of the patient with restricted
disease, access may be exceedingly difficult. Problems with
vascular anastomoses are much commoner in recipients,
particularly females, with fibrotic disease.
Implantation is begun along the posterior part
5
of the bronchus joining the two membranous
portions with a continuous suture. The anterior part
is performed with intra-figure-of-eight sutures. The
completed suture line is then buried by the peribronchial tissues tacked in place with a handful of
interrupted sutures.
The most important steps in the bronchial anastomosis are to ensure that there is a short donor
bronchus so that the suture line is placed as close as
possible to the lung parenchyma. End-to-end apposition of the donor lung, and the separate components should be achieved, particularly avoiding
telescoping or overlapping. Suture material
(absorbable or nonabsorbable) or technique (interrupted, figure-of-eight or continuous suture) are
probably unimportant compared with the principles
of short donor bronchus and accurate tissue apposition. This approach can easily result in a complication rate of less than 2%. Once the bronchial
anastomosis has been completed, the chest cavity
can be flooded with ice-cold saline to ensure the
continued cooling of the still-ischemic lung.
5
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A side-biting clamp is placed on the recipient atrial
6
cuff, and the two ligated pulmonary veins are joined
together into a single orifice. This vessel is then anastomosed easily to the donor atrial cuff using continuous
4/0 polypropylene. It is important to ensure that this
anastomosis is widely patent. The two ends of the stitch
are left untied so as to allow for subsequent de-airing of
the lung.
6
The transplantation is completed by simply trimming
7
and then anastomosing two ends of the pulmonary
artery using 5/0 polypropylene sutures. Orientation is relatively straightforward. The position of the ligamentum relative to the side-biting clamp on the pulmonary artery can be
reconciled with the position of the ligamentum on the donor.
7
Operation 283
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Prior to reventilation, the anesthetist should suction all the
secretions out of the newly implanted lung, ideally under
direct vision with a bronchoscope. The lung now needs to be
de-aired and then reperfused in a controlled fashion.
The pulmonary artery clamp is eased open in a very gradual fashion so as to gently fill the pulmonary artery and its
branches. The previously pale lung will be seen to gradually
turn pink, and blood and a few bubbles of air appear at the
still untied atrial suture line. These should be allowed to exit
from the atrial cuff in an obstructed fashion. The anesthetist
should inflate the lung gently just a couple of times at this
stage. When a flow of blood with no residual bubbles is seen
coming from the atrial suture line, two ends of the suture can
be tied and the atrial clamp removed.
A monitoring cannula, usually tipped with a fine needle, is
introduced into the pulmonary artery beyond the clamp.
Avoidance of high pressure reperfusion is important; and
indeed, events during the first 10 or 15 minutes are vital. The
clamp is gradually removed so as to produce a very damp pulmonary artery flow pattern with a mean pressure no higher
than 20 mmHg and a peak pressure no higher than
25 mmHg. So-called controlled pressure reperfusion is continued for a period of 10 minutes. Abrupt release of the clamp
can expose the ischemic endothelium to a hydrostatic stress
injury. The lung is gently inflated during this reperfusion
phase and then regularly ventilated. At the end of 10 or 15
minutes the pulmonary artery clamp can be completely
removed. Lung function is good; pulmonary artery pressure
hardly rises any further upon fully removing the clamp.
The suture line should be checked for hemostasis. A little
bit of bleeding is always present on the cut edges of the donor
lung collecting flow from pulmonary artery to bronchial
artery collaterals. This bleeding can usually be ignored. Apical
and basal chest drains are placed, and the chest is closed in
routine fashion. Suture lines should again be examined via
bronchoscopy at the completion of the procedure to ensure
that no secretions or in particular blood clots are within the
major airways.
are classically those patients with bronchiectasis, predominantly as a result of cystic fibrosis. These patients are the
prime group for whom the procedure was developed. Its hallmark features such as access through a clam shell incision and
minimal mediastinal dissection have particular advantages in
the setting of inflammatory lung disease. Pleural adhesions
are often dense and vascular in these patients and can easily
be taken out under direct access through the trans-sternal
bilateral anterior thoracotomy incision. The very vascular
and enlarged lymph glands found at the hilum can easily be
dissected and any hemorrhage controlled while at the same
time minimizing the risk of damage to vital structures such as
the phrenic and the vagus nerve.
A large number of bilateral lung transplantations are also
performed for patients with obstructive, emphysematous
disease. Such patients gain an improved exercise tolerance
and probably have an advantage in terms of long-term quality
of life and survival for having two rather than one units of
lung tissue transplanted. The risks of occult sepsis in a
residual native lung together with the problem of overexpansion are also avoided. Suboptimal donor lungs may possibly
be used in the bilateral lung transplantation with a lower risk
than would be the case if a single transplantation was
performed.
The procedure is also attractive for pulmonary hypertensive conditions where the heart is either anatomically normal
or easily repaired. The transplantation of a very large area of
pulmonary vascular bed in the two lungs results in greater
offloading of the right ventricle and less risk of persistent pulmonary hypertension in the postoperative period. In children, this approach has been linked with repair of
intracardiac malformations up to and including pulmonary
atresia, to avoid the need for a combined heart and lung
transplantation.
OPERATION
PREOPERATIVE PREPARATION AND
ASSESSMENT
Bilateral lung transplantation
Patients with septic lung disease require removal of all the
infected material, to all intents and purposes both lungs. They
Bilateral lung transplantation
POSITION
The patient is supine with the arms abducted slightly from the
side. In the original description the arms are elevated over the
face, but we no longer find this necessary. The chest should be
draped as far as the posterior axillary line.
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