Video-assisted thoracoscopic surgery for the treatment of pneumothorax

作者群

摘要

The description of the video-assisted thoracoscopic surgery for the treatment of pneumothorax covers all aspects of the surgical procedure used for the management of pneumothorax.
Operating room set up, position of patient and equipment, instruments used are thoroughly described. The technical key steps of the surgical procedure are presented in a step by step way: examination, resection, pleurodesis, end of procedure, thoracotomy conversion.
Consequently, this operating technique is well standardized for the management of this condition.

媒體類型

刊物

2002-06

普通的

最愛

音訊

數位出版

WeBSurg.com, Jun 2002;2(06).
URL: http://www.websurg.com/doi-ot02en239a.htm

Video-assisted thoracoscopic surgery for the treatment of pneumothorax

1. Introduction

Etiology
Pneumothorax is caused by the entry of air into the pleural space, either via the airways and lungs or via the chest wall following an iatrogenic or traumatic injury. The negative intrapleural pressure changes to positive pressure, and the lung collapses.

Epidemiology
Idiopathic spontaneous pneumothorax is most often observed in teenagers or young adults up to 30 years of age. Secondary pneumothorax occurs mainly in the elderly and is often combined with bullous emphysema and/or chronic obstructive pulmonary disease (COPD).

Pathophysiology
A tension pneumothorax results from any lung parenchymal or bronchial injury that acts as a one-way valve, allowing air to move into but not out of an intact pleural space. The positive pressure used with mechanical ventilation therapy can also trap air. As pressure within the intrapleural space increases, the heart and the mediastinal structures are pushed to the contralateral side. The mediastinum impinges on and compresses the contralateral lung.

Pathogenesis
Ruptured bullae in the apices of the upper lobes are the most frequent cause of spontaneous pneumothorax. An adhesion from the parenchymal base of a ruptured bulla to the parietal pleura is often found during examination of the lung. In addition, smaller bullae may be lined up along the edges of the lobes. However, in at least half the cases of spontaneous pneumothorax occurring for the first time, thoracoscopic inspection finds no cause for the condition.

2. Diagnosis

• Symptoms

Most patients complain of chest pain, at rest or during exercise. The symptoms are usually the same for the second occurrence. In rare cases, a tension pneumothorax with life-threatening dyspnea makes emergency puncture necessary. In case of a spontaneous hemopneumothorax and pneumothorax caused by the rupture of a vessel inside an adhesion, circulatory symptoms may add to respiratory symptoms.

• Chest X-ray

A chest X-ray is the fastest and most reliable diagnostic tool. Large bullae may resemble a pneumothorax. However, the separation between lung tissue and air is usually convex in a bulla, and concave in a pneumothorax.

• CT scan

1. Bullae
CT scan should not be seen as a routine diagnostic step but as an optional tool to differentiate a bulla from a pneumothorax. It is especially useful to detect contralateral bullae.

3. Therapy

General aims
There are 3 aims:
1. Re-expansion of the lung: can be achieved by chest tube drainage only, followed by suction therapy over several days with a negative pressure of about -20 cm H2O.
2. Leakage repair: usually requires surgery that includes suturing, stapling or gluing of the parenchymal leak.
3. Prevention of recurrence: involves different techniques whose goal is to obliterate the pleural space by creating adhesions between the visceral pleura and the chest wall. This pleurodesis may be performed surgically (abrasion, pleurectomy), thermally (cautery, laser) or pharmaceutically (instillation of antibiotics, talc, blood into the pleural space).

Conditions for VATS
Primary spontaneous pneumothorax: whether or not video-assisted thoracoscopic surgery (VATS) is indicated for a first occurrence of primary spontaneous pneumothorax is still under debate. The observed reduction of recurrences following VATS is in favor of the procedure. The cost (anesthesia, procedure, hospital stay) and the fact that a simple drainage cures 50% of the patients are detrimental to VATS.
After 10 years of experience with VATS, we believe that the technique is safe with a skilled thoracoscopic team (Hurtgen et al., 1996). Intrathoracic procedures can be performed as extensively and usually faster than via thoracotomy. Adhesions, eg along the phrenic nerve or along the subclavian vessels, may require conversion to thoracotomy.

Secondary pneumothorax: The same preconditions as for open thoracic surgery are required. VATS may be carried out by surgeons skilled in the technique. Those with less experience in VATS prefer thoracotomy for the treatment of secondary pneumothorax especially when emphysema is present and the lung tissue is fragile. In these patients, it is essential to treat the underlying obstructive pulmonary disease first. In all cases, conversion to thoracotomy can never be excluded.

4. Indications

Indications
- all cases of the first recurrence of primary pneumothorax;
- all cases of the first recurrence of secondary pneumothorax provided that the surgeon has enough experience in VATS and that the patient can tolerate split ventilation.

Relative contraindications
- recurrent primary pneumothorax after surgical treatment,
- previous history of ipsilateral pleural disease.

5. Anesthesia and ventilation

All elective thoracoscopic operations are performed under general anesthesia with a double-lumen tube for separate ventilation of the lung lobes.
With correct positioning of the tracheal tube, the preexisting pneumothorax is completed through passive pressure compensation between the external air and the pleural cavity at the beginning of the operation, thereby leaving the operative site free. If the lung is not completely deflated, endobronchial suction or bronchodilator drugs may be administered. Intrapleural gas insufflation is not necessary. Alternatively to double lumen intubation, a separate bronchus blocker positioned bronchoscopically may be used for single lung ventilation.
It is important to partially inflate the lung during the intervention for the detection of all bullous disorders on the surface of the collapsed lung.

6. Operating room set-up

• Patient

- general anesthesia;
- double-lumen endobronchial intubation;
- lateral position (as for a standard posterior lateral thoracotomy);
- the ipsilateral arm is positioned horizontally to keep the extrathoracic working space free for the instruments.

• Team

1. The surgeon stands in front of the patient.
2. The assistant is placed next to the surgeon.
3. The scrub nurse is placed next to the surgeon.
4. The anesthesiologist is placed at the patient’s head.

• Equipment

1. Videoscopic unit
2. Anesthetic unit
3. Operating table
4. Instrument table

7. Trocar placement

Three trocars are usually required:
- optical trocar: paravertebral, at a maximum distance from the anterior trocars;
- instrument trocars: third and ninth intercostal spaces on the anterior axillary line.
Trocar sizes should be adapted to the diameters of the thoracoscope (10 mm or 7 mm) and of the instruments used. We recommend that a 7 mm thoracoscope be used if available, as a 7 mm trocar is less traumatic for the paravertebral space.
Some surgeons prefer only 2 incisions, whereby 2 instruments are inserted through a single, larger trocar. This technique may be sufficient for simple intrathoracic maneuvers such as wedge resections. It is not suitable for difficult intrathoracic maneuvers, because of the disadvantage of having 2 instruments that may hinder one another in the same trocar.

8. Instruments

• Mechanical instruments

The rigid thoracic wall considerably limits the maneuverability of instruments in the pleural space. As a result, greater demands are made on thoracic instruments than on instruments used for standard laparoscopic operations. At angles greater than 45°, the strong friction within the trocar impedes the movement of the instruments. More freedom of movement inside the thorax can be achieved with angled or curved instruments and by extending the intrathoracic working space into the thoracic dome and to the diaphragm.
Flexible trocars without valves are necessary.

• Other instruments

• HF-cautery

Monopolar and bipolar cutting and coagulation tips or endoscopic scissors are well suited to thoracoscopic pneumothorax surgery. Water irrigation during cauterization of bullae can prevent their carbonization, thus avoiding iatrogenic air leaks.

• Nd:YAG laser

In thoracoscopic surgery, a thermal Nd:YAG laser, as opposed to a CO2 laser, offers the advantage of multi-purpose applications including the coagulation of cysts, hemostasis or bulla resection.

• Argon beam

1. High frequency electrode
2. Argon flow
3. Tissue
The argon beam is especially suitable for hemostasis of wide areas of effusion following pleurectomy. It is uneasy to tell whether a pleurodesis effect occurs as a result of the application of the beam on the parietal pleura. However, if HF-argon pleurodesis is carried out, a large coagulation area on the pleura does not seem to be advantageous (the interruption of vessels may reduce the fibrin supply). It is therefore recommended only to coagulate stripes of parietal pleura, as this ensures expression of the fibrin into the pleural space.
Application of the argon beam inside the pleural cavity is only safe if the pressure compensation between the pleural space and the external air is guaranteed via open trocars.

• Endoscopic stapler

The endoscopic staplers used are especially designed for thoracoscopic resection of lung parenchyma. They ensure safe closure of the tissue along the resection. Four sizes of endostaplers are available (30/35/45/60 mm). The 60 mm stapler, because of its large size, does not always offer free movement inside the thoracic cavity, especially in the thoracic dome. The new flexible staplers do not compensate for this disadvantage.

9. Examination

The first indispensable operative step is a thorough adhesiolysis. Only then is a complete inspection, including the dorsal, mediastinal and phrenic parts of the lung, guaranteed. During inspection, gentle insufflation of air helps make collapsed bullae at the lung surface visible. A concealed bulla on the parenchymal base of an adhesion, for example, can often be clearly identified as the cause of a pneumothorax and must be resected. Synechiae are often found as the consequence of previous pleurodesis or thoracic drainage. They are less vascular and, in terms of recurrence, less significant than the abovementioned adhesions. They must be dissected to allow for a thorough inspection and to avoid pockets of effusion.

10. Resection

• Small bullae

A single bulla with a small parenchymal base is resected using 2 endoloops combined with an additional suture to prevent them from slipping during re-expansion of the lung. The ligation is visually controlled during re-inflation of the lung at the end of the operation.

• Large bullae

Larger bullae with wide parenchymal bases or bullous areas are resected with the endoscopic stapler.
The lung tissue can easily be guided into the stapler with an endoparenchymal clamp, which must be inserted opposite the stapler. To guide the stapler both medially and laterally, the trocar receiving the stapler must be located very low and as posteriorly as possible. When only 2 trocars are used, the stapler and clamp are working parallel to each other, making the insertion of the parenchyma between the jaws of the stapler more difficult.

• Wedge resection

If no bulla or air leak can be found, the procedure of choice is apical wedge resection combined with a partial pleurectomy.

• Alternative technique

As alternatives to bulla resection, laser coagulation or bipolar cauterization have proven to be particularly effective, especially in cases of multiple subpleural bullae. Water irrigation during cauterization of the bulla wall helps prevent a postoperative air leak that could be concealed by charring.

11. Pleurodesis

• Principles

Additional pleurodesis following the repair of the actual air leak can reduce the risk of recurrence by fixing the lung to the chest wall. This prevents the penetration of air from the lung into the pleural space if weakness of the lung parenchyma occurs later.
The pathophysiological principle for creating an adhesion between the lung and chest wall is the secretion of autologous fibrin from the chest wall into the pleural space. Different technical solutions have been devised to this end (Hurtgen et al., 1996; Van den Brande and Staelens, 1989; Wakabayashi, 1989; Inderbitzi et al., 1993).

• Pleurectomy

Partial or total pleurectomy is considered the safest technique for pleurodesis. The parietal pleura can be detached very delicately from the endothoracic fascia in the avascular layer with the videoscopic approach. To begin the pleurectomy, digital detachment of the pleura can be performed before inserting the instrument trocars into the extrapleural space. Blunt dissection with different instruments can be continued extrapleurally under control of the intrapleural thoracoscope. Pleurectomy is performed between the first and fifth ribs, paramediastinally along the internal thoracic arteries and paravertebrally along the sympathetic nerve.

• Pleurodesis

• Mechanical pleurodesis

For mechanical pleurodesis (pleural abrasion), we use a dissecting swab to roughen the pleura until petechiae appear.

• Thermal pleurodesis

For thermal pleurodesis, electrocautery as well as the argon beam technique or laser can be used. The aim is induce a thermal injury of the parietal pleura followed by fibrin secretion.

• Talc pleurodesis

Talc has been used for chemical pleurodesis for decades with high efficacy. It causes tight adhesions between the parietal and visceral pleura, making reoperations difficult. Therefore its application in young patients is controversial. When talc is applied (about 5 g), it should be distributed as a thin layer on the lung or parietal pleura with a sprayer.

12. End of procedure

- re-inflation under visual control;
- chest tubes: usually 2 chest tubes (Ch 28) are inserted through the axillary and inferior incisions and placed under visual control. At least one of the chest tubes should end in the thoracic dome to achieve complete re-expansion under suction of -20 cm H2O;
- closure of trocar wounds.

13. Thoracotomy conversion

Conversion to thoracotomy is not a complication in itself. It may be necessary for intraoperative complications and when the endoscopic technique cannot obtain the same results as open surgery, for instance when wide dissection or extensive suturing is necessary, or when it is feared that certain lesions may be overlooked or when palpation is required.

14. Postoperative period

Chest tubes
When there are no longer any air leaks, suction is stopped and in a postoperative course without complications, the chest tubes can be removed after 2 to 4 days, when the chest X-ray shows a complete re-expansion of the lung and no pleural effusion. The methods for handling chest tube drainage vary from one hospital to another and depending on the experience of the surgeon.
The medium postoperative drainage time for idiopathic pneumothorax is 4 days after a VATS procedure compared to 6.5 days after thoracotomy. For secondary pneumothorax, however, the difference between thoracotomy and the thoracoscopic approach is not significant. In these cases, longer drainage periods are related not to access but to prolonged air leaks caused by emphysematous lung parenchyma.

Analgesics
Reduction of postoperative pain and shorter drainage periods are the major quality criteria of the minimally invasive approach. In our protocol, patients receive analgesics regularly during the drainage period. Oral analgesics during the initial postoperative period may be sufficient. However, IV therapy or a peridural pain catheter may be better. It is important to eliminate pain in order to mobilize the patient immediately after surgery. In some patients, analgesics may be required for several weeks postoperatively.

Postoperative course
In more than 80% of patients, lung function returns to normal values 6 weeks postoperatively for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). In the remaining patients, a moderate restrictive lung function with values for FEV1 of about 75% of the normal value can be found.
In our own experience, the overall recurrence rate ranges from 3% to 8% following VATS pneumothorax treatment and is similar to the figures found in the literature (Mouroux et al.,1996).

15. Complications

Mortality
The mortality rate for VATS pneumothorax therapy should be zero for patients with primary spontaneous pneumothorax. Patients with secondary pneumothorax are usually elderly patients with severe emphysema and chronic obstructive pulmonary disease. Therefore, postoperative mortality may occur, depending on the severity of the underlying disease.

Bleeding
Severe bleeding from the internal thoracic and intercostal arteries is rare but possible. It can be controlled either by VATS or through conversion, depending on the experience of the surgeon. Diffuse postoperative bleeding should be expected more frequently following pleurectomy than in patients on whom pleurodesis was not performed (Naunheim et al., 1995).

Trocar injuries
Trocar injuries can be avoided by dissecting the trocar channels with scissors under digital control and by only using blunt trocars.
The overall rate of complications can be estimated at 5% to 8% and is no higher than that for thoracotomy.

16. Conclusion

Recurrence rates following VATS are comparable to those for conventional thoracic surgery. Important advantages of VATS include an accelerated recovery and decreased operative trauma.
Experience has shown that thoracoscopy provides a better view of the thoracic cavity, especially in the upper and lower parts of the thorax when compared with open surgery. The magnification effect of the thoracoscope allows for a much more precise separation of the pleura from the endothoracic fascia (Naunheim et al., 1995).

However, substantial experience is necessary to keep the rate of complications below that of thoracotomy. For example, postoperative bleeding is usually caused by a videoscopic miscalculation of the hemostasis of the chest wall after pleurectomy. The inspection of the total lung surface is more difficult by video-thoracoscopy as compared to open surgery, especially under intraoperative ventilation when checking for air leaks or bullae.

17. Reference

Hurtgen M, Linder A, Friedel G, Toomes H. Video-assisted thoracoscopic pleurodesis. A survey
conducted by the German Society for Thoracic Surgery. Thorac Cardiovasc Surg 1996;44:199-203.
Inderbitzi RG, Furrer M, Striffeler H, Althaus U. Thoracoscopic pleurectomy for treatment of
complicated spontaneous pneumothorax. J Thorac Cardiovasc Surg 1993;105:84-8.
Naunheim KS, Mack MJ, Hazelrigg SR, Ferguson MK, Ferson PF, Boley TM et al. Safety and efficacy
of video-assisted thoracic surgical techniques for the treatment of spontaneous pneumothorax. J
Thorac Cardiovasc Surg 1995;109:1198-203; discussion 1203-4.
van den Brande P, Staelens I. Chemical pleurodesis in primary spontaneous pneumothorax. Thorac
Cardiovasc Surg 1989;37:180-2.
Wakabayashi A. Thoracoscopic ablation of blebs in the treatment of recurrent or persistent
spontaneous pneumothorax. Ann Thorac Surg 1989;48:651-3.

使用者名稱
密碼
	記得我 (必須啟動Cookies設定)