The term VATS is often used and stands for video-as- sisted thoracoscopic surgery. This technique pro- vides excellent view of the internal thoracic anatomy.

INTRODUCTION

Pediatric surgeons have been involved in thoracosco- py for a long time. Until the late 1980s most thoracos- copies were purely diagnostic. The explosion of en- doscopic surgical techniques came shortly after the introduction of the chip camera and video technolo- gy into surgery. Since that time most of the opera- tions that have been classically performed through a formal thoracotomy can now be performed in a vid- eo-assisted way using a number of small access holes.

The term VATS is often used and stands for video-as- sisted thoracoscopic surgery. This technique pro- vides excellent view of the internal thoracic anatomy.

Additionally, it avoids trauma to the thoracic wall not only as a result of the transection of the various tis- sues but also because of the spreading of the ribs.

The following are indications for VATS:

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Diagnostic procedures

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Interstitial lung disease

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Metastatic lung disease

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Mediastinal lesions

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Therapeutic procedures

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Chest wall

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Empyema

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Pectus excavatum correction according to the Nuss method

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Trachea and lungs

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Tracheomalacia

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Pneumothorax

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Bronchogenic cysts

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Sequestration

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Lobectomy

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Metastases

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Mediastinum

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Thymus – Thymectomy

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Heart and great vessels

– Closure of the ductus arteriosus – Pericardial cysts

– Vascular access

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Esophagus – Atresia – Achalasia – Duplication

– Esophagectomy for caustic burn

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Sympathetic chain – Neurogenic tumours

– Sympathectomy for hyperhydrosis

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Thoracic duct – Ligation

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Spine

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Anterior spinal fusion

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Diaphragm

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Diaphragmatic hernia, eventration, relaxation

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Diaphragmatic pacing

Thoracoscopy has also gained a definitive position in

the treatment of childhood and adolescent cancer.

Klaas Bax

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A good working space is of paramount importance for good quality VATS. In children the working space is very limited, a greater reason to make all available space available. The organ that limits the working space during VATS is most usually the lung. Tech- niques have been developed to keep the lung out of the way.

By allowing air to enter the pleural cavity, the lung will collapse. However, VATS is usually done under general anaesthesia and positive pressure ventila- tion. As a result, the lungs expand during each insuf- flation. One-lung ventilation by selective intubation of the main bronchus with a cuffed tube (Fig. 1) or by the use of a double lumen tube is a good alternative but only applicable in larger children, e.g., children over 10 years of age. In children below 10 years of age, one lung ventilation is theoretically possible by ven- tilating the child endotracheally while the ipsilateral main bronchus is blocked with a Fogarty catheter.

Such a technique, however, is not simple and de- mands a high level of expertise as well as time.

Instead of one-lung ventilation, the lung can be pushed out of the way by inflating the ipsilateral tho- rax with CO

. Pressures of up to 5 mmHg at a flow of 2 l/min are well tolerated, even in the neonate. After a short while, the ipsilateral lung collapses, and once that stage is reached an even lower inflation pressure usually suffices. In order to maintain the CO

pneu- mothorax, valved cannulae have to be used. The res- piratory pressure will be increased by the same amount as the CO

inflation pressure and hypercap- nia will occur as a result of CO

absorption. Both can be managed by adjustment of the ventilator settings, e.g., by increased rate and minute volume. Close col- laboration between surgeon and anaesthesiologist is mandatory. It is very important that the surgeon is patient enough to allow the body to seek a new equi- librium.

Figure 10.1

Figure 10.2

The surgeon, the operative target area and the screen should be inline. This means that the surgeon stands behind the back of the patient for anterior mediasti- nal surgery and in front of the patient for posterior

mediastinal surgery. The cameraman, when right-

handed, usually stays to the left of the surgeon. The

scrub nurse usually stands on the opposite side.

Anesthesiologist

Scrub nurse

Assistant Surgeon

Figure 10.2

Klaas Bax

Figure 10.3, 10.4

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Gravitational forces should also be used to get the lung out of the way. This means that the position of the child on the table has to be adjusted to take max- imal advantage of these forces.

For anterior mediastinal surgery a three-quarters posterolateral decubitus position should be chosen;

for posterior mediastinal surgery rather a three- quarters anterolateral decubitus position should be used. Moreover, for VATS in the upper part of the chest, the table should be put in a reversed Trenden- burg position, whereas for VATS in the lower part of the chest the table should be put in a Trendelenburg position. When all above measures are taken, usually no retractors are needed. If they are needed, they should be used with care as they can easily damage the organ that has to be retracted.

The cannulae can be inserted in a closed or open way. When the closed way is chosen, a radially ex- pandable cannula is usually used. A Veress needle with radially expandable sheet is punctured through the intercostal space at the desired place. Air is al- lowed to enter the chest through the needle so that the pleurae detach. The Veress needle is then re- moved and the sheath left behind for dilatation with the cannula and blunt trocar.

In the open way, a small incision is made through the skin. Next, the wound is deepened just over the upper border of the rib until the pleural cavity is

opened and air is sucked into the chest. Next a cannu- la with blunt trocar is inserted. The hole in the thorax wall for the cannula should be as small as possible so that the tissues fit snugly around the cannula in order to avoid CO

leakage. All secondary cannulae are in- serted in the same way but under concomitant tele- scopic control.

Especially in small children, who have a rather thin body wall, cannulae have a tendency to glide fur- ther into the body cavity, thereby further limiting the working space, or to glide out. Using radially expand- able cannulae may lessen this. Cannulae with a screw on the outer side should not be used, as these will be pulled out resulting in a rather large hole. The best way to prevent this gliding in and out is to put a snug- ly fitting sleeve of silastic tubing around the cannula.

The sleeve can then be sutured to the skin. Alterna- tively the stopcock of the cannula is sutured to the skin and circular tape is applied around the cannula and tied at the base.

The most ergonomic position of the cannulae is

triangular or V-shaped. The tip of the V is directed

towards the surgeon and the open side of the V to-

wards the patient. The telescope cannula is inserted

at the tip of the V while the cannulae for the working

instruments are positioned at the top of the limbs of

the V. Ideally the angle of the V should be around 60°.

Klaas Bax

Figure 10.5

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The smaller the diameter of the telescope, the less good the quality of the picture is and the less light that can be transmitted. Telescopes with a diameter of 5 mm are of sufficient quality to be used for all en- doscopic operations in children. The optical axis can vary with the axis of the physical axis of the telescope from 0° to 75°. The most commonly used scopes have an angle of 30°. In contrast to 0° scopes, angled scopes allow one to look around structures, which has great advantages. Most telescopes have a length of 33 cm. For use in small children, the 24-cm length is advantageous.

For most endoscopic surgical operations in chil- dren, instruments with a diameter of 3.5 mm, to be used in conjunction with cannulae with a diameter of 3.8 mm, are appropriate. In neonates and infants, 20- cm long instruments instead of 30-cm long ones should be used. These 3.5 mm instruments can be used with monopolar high-frequency electrocautery (HFE), which suffices for most operations in smaller children.

Ligating loops can be used to seal leaking lung or the take a lung biopsy.

For the application of bipolar HFE or of ultrason- ic energy, the minimal diameter of the instrument is 5 mm. This also applies for the endoscopic Ligasure instrument, which is a sophisticated bipolar HFE in- strument allowing one to seal vessels with a diameter up to 7 mm in diameter. These 5-mm instruments are rather long to be used in small children.

Clipping devices also have a minimal diameter of 5 mm and are quite long.

Stapling devices require an 11-mm diameter can- nula, which is enormous for small children. Such a cannula will damage the intercostal space in small children and should therefore be avoided. Moreover, these staplers need a deep working space to allow the stapling beak to be opened and closed.

Tying and especially suturing of structures are con- sidered to be the most difficult endoscopic surgical tasks and are the Achilles heel of endoscopic surgery.

Tying of blood vessels structures has been largely eliminated by the availability of new energy-applying systems, which allow even large blood vessels to be well sealed. Pre-tied loops can be used for, for exam- ple, tying-off leaking lung tissue. There are also dis- posable suturing devices on the market but these have a diameter of 10 mm.

The problem of suturing is certainly not solved at the present. A major problem in endoscopic suturing is the introduction of the needle. Most needles just don’t fit 3.8 mm cannulae. In small children, the nee- dle can be put directly through the body wall. Once the suturing has been finished, the needle has to be directed back through the wall. This process is time consuming especially when many sutures have to be applied as, for example, in oesophageal anastomosis.

Another possibility is to straighten the curved needle

so that it will fit together with the needle holder

through the cannula. The tying of the knot can be

done extracorporeally or intracorporeally.

Klaas Bax

CONCLUSION

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VATS has revolutionized surgery not only in adults but also in infants and children. Almost all opera- tions were classically performed through a thoracot-

omy can now be performed using VATS. VATS gives a perfect view of the anatomy and dissection is not particularly difficult. The difficulty is suturing.

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