Surgery in pleuro-pulmonary tuberculosis: On the comeback trail

Nasser Yusuf; CP Rauf; Nihal Yusuf

doi:10.4103/astrocyte.astrocyte_67_17

THE OPERATING ROOM - IN THE REALM OF SCALPEL

Year : 2017 | Volume : 4 | Issue : 2 | Page : 111-124

Surgery in pleuro-pulmonary tuberculosis: On the comeback trail

Nasser Yusuf¹, CP Rauf², Nihal Yusuf³
¹ Cardiothoracic Surgeon, Chest Hospital, Calicut and KIMS, Kochi, Kerela, India
² Pulmonologist, Chest Hospital, Calicut, Kerela, India
³ Surgeon, Jubilee Mission Hospital, Thrissur, Kerala, India

Date of Web Publication

30-Nov-2017

Correspondence Address:
Nasser Yusuf
Chest Hospital, Pavamani Road, Calicut - 673006, Kerala
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/astrocyte.astrocyte_67_17

Abstract

The birth of modern antitubercular chemotherapy in mid-1950s relegated the status of pleuro-pulmonary surgery to being on the backburner. However, since the time MDR-TB and XDR-TB strains have emerged, considerable interest stands rekindled in the realm of the scalpel. Pleuro-pulmonary surgeries have become an indisputable ally of the current molecular drug therapies in a bid to scale back the morbidity and mortality of the disease. While such complications as bronchiectasis – with its attendant risks of suppuration, superinfection, and hemoptysis, together with known destructive pulmonary sequelae such as destroyed lung, massive hemoptysis, bronchopleural fistula and empyema have become distinct grounds for surgical intervention, the presence of a pulmonary aspergilloma or a resectable neoplasm in a destroyed lung, makes the patient a fit case for corrective surgery. Mediastinal tuberculous lymphadenitis, associated with compressive symptoms and pulmonary complications, particularly in children, is another classic ground for surgical decompression of the bronchial tree. Making a compelling preference in such clinical landscapes which do not respond to medical treatment, are serious, and potentially fatal, pleuro-pulmonary surgery is currently well and truly on the comeback trail in the management of thoracopulmonary tuberculosis.

Keywords: Drug-resistant tuberculosis, indications, thoracic surgery, tuberculosis

How to cite this article:
Yusuf N, Rauf C P, Yusuf N. Surgery in pleuro-pulmonary tuberculosis: On the comeback trail. Astrocyte 2017;4:111-24

How to cite this URL:
Yusuf N, Rauf C P, Yusuf N. Surgery in pleuro-pulmonary tuberculosis: On the comeback trail. Astrocyte [serial online] 2017 [cited 2023 Jun 4];4:111-24. Available from: http://www.astrocyte.in/text.asp?2017/4/2/111/219476

Introduction

Since the middle of the 20th century, pulmonary tuberculosis (PTB) has largely been a malady treated by the physicians. Just as modern antitubercular chemotherapy came to the fore, surgery simply faded away. However, the emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug resistant tuberculosis (XDR-TB) has transformed the clinical landscape.^[1] With antitubercular drug regimens failing in up to 15% or more patients in geographical areas where MDR-TB strains are prevalent, thoracopulmonary surgeries are back in business. Surgical resections can eliminate the disease where modern antitubercular chemotherapy cannot decimate a resistant strain of tubercular bacillus. Buoyed by favorable results, whereby a pulmonary resection combined with anti-TB chemotherapy for MDR-TB has achieved treatment success rates in some settings of up to 88–92% of cases, surgical interventions are increasingly being carried out in PTB. Data accumulated over the last 20 years indicates that the quotient of surgical intervention may have increased from 5% to 15%.^[2]

Indications For Surgery

Often, a surgery referral in PTB is delayed much until later when the treatment has been failing, a large part of the lung parenchyma stands destroyed, and the patient is extremely symptomatic. The trick for the physician is to recognize such treatment failures early and call for early surgical evaluation before the disease has advanced too far. A timely surgical correction offers not just a relief of symptoms but also a possible cure. The current indications for surgical treatment of PTB, MDR-TB and XDR-TB are as follows.

Emergency indications

Emergency indications – that is, without surgery death is imminent and unavoidable – include:

Profuse lung hemorrhage
Tension spontaneous pneumothorax

Urgent indications

Urgent indications include:

Irreversible TB progression, despite adequate anti-TB chemotherapy
Recurrent hemoptysis that cannot be stopped by other treatment methods

Elective indications

Even though there is not enough evidence to define the characteristics of cavities and other irreversible changes in MDR/XDR-TB patients that can lead to a high probability of failure of TB chemotherapy and relapse, much of the data favors the following indications as being conducive for elective surgery.^[3],[4]

Localized forms of cavitary TB with continuous M. tuberculosis excretion confirmed by bacteriological examination and DST after 4 to 6 months of supervised anti-TB chemotherapy;
M/XDR-TB characterized by failure of anti-TB chemotherapy;
Complications and sequelae of the TB process (including MDR/XDR-TB):

Other miscellaneous indications

Major Criteria for Determining Ideal Candidates for Surgery

A suitable selection of patients and a correct timing of surgery are two critical determinants to avoid relapses and to provide a greater possibility of cure. A first-rate cooperation between the treating physician and thoracic surgeon, as well as patients' adherence to pre- and postoperative intervention chemotherapy, can increase the success rate of MDR-TB treatment.

For patients to be considered as candidates for surgery, three major criteria must be met:

The patient must have localized disease amenable to resection and with an adequate respiratory reserve;
The patient must have extensive drug resistance, making the likelihood of treatment failure or relapse very high; and
A sufficient quantity of second-line drugs must be available to ensure healing after surgery. In the case of bilateral lesions, resection should be performed on the side with the greater lesions.

Surgery should be seriously considered when:

The disease is sufficiently localized to allow surgery;
The remaining lung tissue around the resection margins is estimated to be free of TB;
The patient's surgical risk level is acceptable, with sufficient pulmonary reserve to tolerate resection.

In any case, irreversible pathomorphological changes in the affected lung(s) are a significant additional indication for surgery. In all cases, surgery is only indicated if there is possible benefit (resection of lung or other below mentioned types of operations) without significant threat to life or damage to patient's lung function.

Types of Operations

The following are the types of operation currently performed:

Lung resections of different size:

Extrapleural thoracoplasty;
Extrapleural pneumolysis;
Thoracomyoplasty;
Pleurectomy and decortication of lung;
Operations on the bronchi:

Thoracocentesis and thoracostomy;
Artificial pneumothorax and pneumoperitoneum

Contraindications for Surgical Treatment

In the majority of cases, contraindications for the surgical treatment of TB patients depend on how extensive the operative process is to be, assessment of the patients' cardiopulmonary function and their general state of heath.

The following are taken as contraindications for lung resection:

Extensive cavitary lesion of both lungs;
Impaired pulmonary function test; that is forced expiratory volume in one second less than 1.5 L in cases of lobectomy and less than 2.0 L where pneumonectomy is planned. The minimum acceptable predicted post-operative FEV1 is 800 ml for pneumonectomy
Pulmonary-heart failure III–IV (functional classification of the New York Heart Association);
Body mass index up to 40–50% of the normal range;
Severe co-morbidity (decompensation in diabetes, exacerbation of stomach and duodenum ulcers, hepatic or renal impairment);

Methods to Predict Postoperative Lung Function

The four validated methods to predict postoperative lung function are:

Anatomic calculation
Split radionuclide perfusion scanning (V/Q scan)
Quantitative CT scanning
Dynamic perfusion magnetic resonance imaging (MRI)

Surgical Treatments in Diverse Clinical Settings

Massive hemoptysis

Definition

Severe or massive hemoptysis is defined as expectoration of 300-600 mL of blood in 24 hours or of at least 200 mL of blood on each occasion. 1–1.5% of hemoptysis fall under this category. Massive hemoptysis can be life threatening either as a result of compromised gas exchange or exsanguination.

Causes

Development of systemic bronchial circulation at the nidus of infection results in massive hemoptysis. Small dilation of vessels due to the involvement of pulmonary vasculature in the wall of cavities form Rasmussen's aneurysm. Rupture of bronchial arteries or Rasmussen's aneurysm causes bleeding. In bronchitis, chronic inflammation of bronchial wall and in bronchiectasis destruction of bronchial wall causes hemoptysis. Bleeding could be severe as pressure in the bronchial arteries are higher than the pressures in pulmonary arteries making it difficult to control.

A tuberculosis cavity can invade the parietal pleura and chest wall, erode intercostal or subclavian or internal mammary arteries and cause hemoptysis. The development of a fungal infection in an old TB cavity producing a mycetoma (aspergilloma) is another major cause for hemoptysis.

Broncholithiasis is known to cause severe hemoptysis due to erosion of bronchial wall and peribronchial arteries. The pathology is the deposition of calcium on peribronchial lymph nodes during healing of tuberculous granulomas.

Management

Bronchoscopy combined with imaging technology usually identifies the bleeding site in the lungs. However, in 15-20% of the cases, the cause of hemoptysis remains undetermined.^[5] Bronchial arteriography and bronchial artery embolization (BAE) provides a rapid diagnosis and treatment in massive hemoptysis. The hemostatic effects of BAE are unpredictable and relapses are possible. The only means to overcome this is by removal of underlying disease.^[6] Incomplete embolization, recanalization of embolized vessel, development of collateral vessels, or bleeding from a pulmonary artery branch are the many reasons for recurrence of hemoptysis. BAE is thus a temporary treatment to stop acute bleeding so that the patient can be prepared for possible surgery.

Operative intervention

In most cases, lobectomy is the standard operation, as it is rather difficult to define the bleeding segment. In some cases, pneumonectomy is mandatory due to a destroyed lung or when the bleeding site is lateralized but not localized [Figure 1]. The complication rate is reported to increase in emergency pneumonectomy when compared with emergency lobectomy.^[7] Surgery offers a definitive curative treatment for hemoptysis because it removes the source of bleeding.

Figure 1: Longitudinal section of left lung showing multiple cavities in upper lobe along with destroyed lower lobe.

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Results

The operative morbidity rate ranges from 20 to 31.5% and mortality from 2.2 to 8.3% as compared to 11.5 to 29.1% mortality rate in those treated conservatively.^[8] Bleeding during operation and aspiration to uninvolved lung and hypovolemia increases mortality in an emergency situation.

Cavernoma (Cavity)

Cavities are usually located at apices of lung. This is due to local and limited parenchymal destruction [Figure 2] and [Figure 3]. Reactivation of the disease and formation of aspergillomas can occur. Persistent localized forms of cavitary TB with continuous M. tuberculosis excretion confirmed by bacteriological examination and DST after 4 to 6 months of supervised anti-TB chemotherapy is thus a major indication for surgery.

Figure 2: Chest radiograph PA view (A) of a patient who presented with massive hemoptysis owing to active cavitary TB in the right lower lob.

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Figure 3: CT scan (B) of a patient who presented with massive hemoptysis owing to active cavitary TB in the right lower lobe.

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For the weak and debilitated, collapse therapy in the form of thoracoplasty and plombage is helpful.

A viable alternative is cavernostomy, wherein the cavity is laid open, drug instilled to sterilize it and the bronchi closed. The cavity is then obliterated with stitches or muscle plombage (Perelman and Strelzov, 1997).^[9]

Resectable lung cancer

The evidence for association of lung cancer and TB is sufficiently strong to warrant close followup. A parenchymal scar that has shown no change for many years may transform into malignancy and could occur by way of two pathways.

Local erosion of the caseous granuloma or systemically due to debilitation by lung malignancy can reactivate TB. The other is Scar carcinoma which is healed TB where cancer may rear its ugly head. Poor clearance of carcinogens or the metaplasia associated with healing and the production of growth factorlike substances maybe the triggering factors for development of malignancy.

Dacosta and Kinare reported 29 cases of TB associated with 221 cases of mostly undifferentiated carcinomas, as well as adenocarcinomas of the lung.^[10] In another study of 124 patients with coexisting bronchogenic carcinoma and pulmonary TB, Snider and Placik found that TB preceded the discovery of carcinoma in 56% of the patients, and in 44% of the cases, the two conditions were synchronous and were documented within 6 months of each other.^[11]

The recovery of acidfast bacilli in suspected cases of bronchogenic carcinoma should never give a false impression and should be thoroughly investigated for cancer. Thus, patients with a past history of TB need checkups at regular intervals for early detection of recurrences and appearance of scar carcinomas.

Tracheoesophageal or bronchoesophageal fistula

Infrequently, fistulas are produced by the continuous pressure of infected mediastinal nodes which lie between the trachea and the esophagus. They may occur at any level of the tracheobronchial tree - trachea, both left and right main stem bronchi and occasionally right lower lobe bronchus.

A trial of medical therapy is always warranted, unless an emergent situation arises, because some of these fistulas respond well to medication. Surgery is elaborate which requires closure of the esophageal defect, resection of the affected trachea, and reinforcement with tissue.

Symptomatic and chronic post-TB bronchiectasis

Bronchiectasis is a well known sequel of PTB and is caused by fibrosis and destruction of the lung, resulting in retraction and dilation of the bronchi. It can also occur as secondary to bronchial obstruction causing bacterial colonization [Figure 4] and [Figure 5]. Fibrosis or extrinsic compression by cavities or enlarged lymph nodes causes bronchial stenosis leading to obstruction.

Figure 4: CT thorax of lower lobe of right lung with localized bronchiectasis.

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Figure 5: Cross section of resected lower lobe of right lung with localized bronchiectasis.

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Bronchiectasis associated with TB presents with recurrent and at times massive hemoptysis, the source usually being from apical and posterior segments of the upper lobes (dry bronchiectasis). It often presents as chronic or recurrent infection (wet bronchiectasis). If the hemoptysis and infection is recurring despite adequate medical management, surgical resection should be performed in localized lesions. Surgery in bilateral bronchiectasis as palliation if not curative is feasible if the lesions again are localized and enough lung parenchyma can be left behind.

Extrinsic airway obstruction by TB lymph nodes, broncholith, bronchonodal fistula

Nearly half of the patients with pulmonary TB harbor enlarged mediastinal lymph nodes, of which only 2% cause airway compromise. This requires surgical attention. Attempts to excise the entire lymph node may lead to lacerations of the airways.^[12]

These nodes when they become necrotic have the tendency to rupture and discharge caseum into the bronchial lumen causing bronchonodal fistula. This is seen especially in the elderly and is a potentially fatal condition as it causes severe respiratory compromise. The site of occurrence of the bronchonodal fistula on the right side is between the lobar bronchi and paratracheal or hilar lymph nodes and on the left side between the left main bronchus and subcarinal lymph nodes.

Calcified lymph nodes known as broncholiths may behave in a similar fashion causing bleeding and obstruction. Cartilages are soft and weak in children as they are ill-developed and hence are easily compressed by enlarged lymph nodes.

Endobronchial tuberculosis and bronchostenosis

Endobronchial tuberculosis (EBTB) is seen in 10–37% of patients with pulmonary TB and is associated with significant morbidity and potential mortality.^[13] Bronchoscopy is essential for early diagnosis. Aggressive treatment with antituberculous chemotherapy is necessary in the management of EBTB to prevent complications such as tracheobronchial stenosis [Figure 6].

Figure 6: CT scan of the thorax demonstrating left bronchial stenosis.

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Corticosteroids may be useful in the early stages of EBTB when hypersensitivity is the predominant mechanism, especially in children. They may acutely reduce bronchial narrowing and the extent of post-stenotic lung damage. Verhaege et al. demonstrated resolution of EBTB with submucosal methylprednisolone injection.^[14]

There are various bronchoscopic interventions to relieve airway stenosis including balloon dilatation, stent insertion, laser, and cryosurgery. The incidence of restenosis is approximately 37.5% a month after balloon dilatation alone.^[15] Adjuvant submucosal methylprednisolone injection further decreases the incidence. Persistent symptomatic bronchial stenosis, which causes severe bronchiectasis, lung collapse, repeated pulmonary infection, or frequent hemoptysis may require pneumonectomy or lobectomy.

Middle lobe syndrome

Isolated atelectasis of the middle lobe is known as middle lobe syndrome. Atelectasis of lingula alone is now described as well. Extrinsic nodal compression of the bronchus of lingula or middle lobe results in postobstructive atelectasis, bronchiectasis, and pneumonitis. Resection of the affected parenchyma leads to a cure. Prior to this, screening for TB should be done and an endobronchial lesion ruled out.

Aspergilloma

The most common clinical presentation of aspergilloma is hemoptysis, which in some series occurs in up to 91% of the patients.^[16] Vascular erosion by the fungus or the production of endotoxins with hemolytic properties is the cause of hemoptysis and is associated with mortality rates varying from 25% to 100%.^[17] Aspergilloma exists in a tuberculous cavity and is a fungus ball made of hyphae tangled with necrotic debris, inflammatory cells, and red blood cells [Figure 7].

Figure 7: Longitudinal section of upper lobe of left lung with Aspergilloma.

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Medical therapy for aspergillomas is usually ineffective. Cavernoscopic evacuation followed by repeated intracavitary instillation of antifungal agents has been used successfully as an alternative method of palliation in patients for whom surgery would be a great risk.^[18] Bronchial artery embolization can be used as a bridge to surgery. Resection is the cure and operative mortality rates are in the range of 5–7%, with complications being low, especially in the absence of active TB.^[19]

Progressive disease and lung destruction

Lung destruction occurs in 1% of all patients with PTB. Late presentation, errors in diagnosis, poor compliance, or insufficient treatment accounted for the causes. The disease appears on radiography as very extensive characterized by fibrosis, cavitation with caseous lesions, and sublobar bronchiectasis [Figure 8]. The hilum is pulled upwards, mediastinum is shifted towards the affected side and the intercostal spaces are narrowed. The most common presentation is chronic bacterial superimposed infection, hemoptysis, and shortness of breath.

Figure 8: Coronal section of CT thorax showing cavities in a destroyed right lung.

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When compared to the right the left lung is more prone to destruction following PTB. This is probably because of the left main stem bronchus being longer and narrower than the right and compression by the aorta. This entity is known as the left bronchus syndrome. Pneumonectomy is the treatment for destroyed lung. In a series of 118 patients who underwent pneumonectomy for destroyed lung, Halezeroglu et al. (1996) reported that the combined morbidity and mortality rate of the operation was significantly higher in patients with TB, co-existing empyema or who had right pneumonectomy compared to the left.^[20]

Drug resistance

Once ATT has been initiated, sputum conversion occurs within 3 months provided the bugs are sensitive. Any period beyond that should raise the possibility of drug resistance. Administration of medical therapy alone will not suffice and is associated with a 50% mortality.^[21]

Drugresistance tuberculosis (DRT) is defined as TB caused by an isolate of Mycobacterium tuberculosis (MTB) that is resistant to one or more antituberculous drugs. The term Multidrug-resistant TB (MDR-TB) refers to TB that is resistant to both isoniazid and rifampicin and possibly additional agents. Management of these cases is extremely vexing because of the large number of drugs required, each with its own toxicity and high cost.

The presence of MDR-TB with HIV makes matters worse. In 1992, Busillo et al. reported a mortality rate of 62% in 24 patients with HIV who were infected with MDR-TB.^[22]

Cavitation on the chest radiographs and CT has been found to be common among persons afflicted with MDR-TB. Facing the challenge of MDR-TB, in selected patients with localized disease who do not respond to chemotherapy, the combination of pulmonary resection and secondline anti-TB agents achieve cure rates of up to 90%.^[23]

The clinical objective of lung resection in MDR-TB is culture conversion to cure patients, prevention of future relapses, and further M. tuberculosis transmission. Surgery removes a major focal burden of tubercle bacilli contained within necrotic and nonviable lung tissue. Studies advocate surgical resection in sputumpositive cases if the patient has a cavitary lesion or destroyed lung or lobe, as well as areas of nodularity as these may be harboring microabscesses.^[24] The reason for resection in patients with cavitary lesions is the difficulty of antibiotic penetration.

Indications for surgery in drug-resistant tuberculosis are:

Persistently positive AFB smear or sputum culture despite aggressive chemotherapy
High risk of relapse (based on drug resistance profile and radiological findings)
Localized lesion
Complications of TB including bronchiectasis, empyema, hemoptysis

A recent metaanalysis reported a treatment success of 84% for pulmonary resection in MDR/XDR-TB patients, with a 6% failure rate, 3% relapse, and 5% mortality.^[25] Excessive surgical delay, more than 3 months of medical therapy, may favor disease progression and development of further drug resistances, although some authors suggest that surgery can be performed after a period of 6 to 8 months with better success rates.^[26] A maximally parenchymalsparing surgery is recommended whenever possible since disease relapse may occur despite adequate surgical intervention and appropriate chemotherapy.

The balance of removing all affected lung and the desire to preserve pulmonary function is used to determine which type of resection is done – wedge resection, segmentectomy, lobectomy or pneumonectomy. In patients with bilateral cavitary lesions, the largest lesion is usually resected or in a minority of cases where sputum conversion does not occur, a staged resection of contralateral lesions is done.

Perioperative morbidity and mortality rates are between 0–39% (median 23%) and 0–5% (median 1.3%), respectively.^[27] It is observed that there is an increased incidence of complications in patients undergoing surgery with MDR-TB than with drug sensitive TB (23% vs. 10%). These complications include intrathoracic bleeding, empyema, bronchopleural fistula, prolonged air leak, respiratory failure requiring ventilation, arrhythmias, and rarely recurrent laryngeal nerve damage and chylothorax.

Preoperative hemoptysis and low baseline pulmonary function (FEV1 <1000 ml or vital capacity <50%) are significant risk factors for postoperative complications.

As per a cohort study done in South Africa, the results of medical treatment particularly for XDR-TB are dismal with cure rates of 7% at 2 years and 5% at 5 years and mortality of 46% at 2 years and 73% at 5 years.^[28] In these patients, surgical resection with localized disease may offer the only hope for cure given the limited available treatment options.

Cohort sizes measuring the effect of surgery on outcomes range from 205–1407 patients with between 4–63% undergoing surgical resection. The overall favorable outcome rate range from 18–75% (median 66%), with the poorest outcome (18%) seen among the XDR-TB only cohort.^{[29],[30],[31]}

Because of the significantly better rate of cure, presence of MDR-TB/XDR-TB in localized disease is an indication for surgery. Surgery decreases the bacterial burden, but rarely does it eliminate it. Therefore, drug therapy must be continued postoperatively for a period of 18–24 months.

No randomized, controlled trials of surgical resection are on record, and there are many and disparities in patient selection for surgery. Operating on “healthier” patients is a common bias. However, even with these limitations, it is reasonable to consider surgical resection early in the course of treatment for MDR-TB and XDR-TB based on the available data.

Undiagnosed pleural effusion

Involvement of the pleura is the second most common extrapulmonary manifestation and occurs in 5% of TB patients. The rupture of a primary caseous lesion in the lung into the pleural space leads to the dissemination of MTB in the fluid as well as in the pleura.

There is no specific time for pleural effusion to present and is found in both primary and reactivation phases of TB. Rarely, it may present as chest wall masses and pleurocutaneous sinus tracts.

Although tuberculous pleural effusions can regress spontaneously in 8 weeks, active PTB develops in 30–50% of such patients, indicating the importance of diagnosing and treating these effusions early.^[32]

The pleural fluid of tuberculous effusions is clear and is light yellow in color and the biochemistry favors an exudate. Interestingly with time, the concentration of cholesterol increases and in some cases the pleural fluid may take a milky appearance (pseudochylothorax). Cholesterol levels in the effusion may be well beyond 150 mg/dL, however bereft of chylomicrons.

Pleural fluid cultures are notorious for its sensitivity with a poor yield of MTB in 50% of cases.^[33] Pleural biopsy confirms the diagnosis in 75 to 80% of patients by demonstrating the presence of MTM or granulomas. Bedside pleural biopsy is the first and simple tool to obtain a diagnosis, should it fail, it should necessarily be followed up with diagnostic thoracoscopy.

Surgery is reserved for patients who have large or symptomatic effusions. The management of pleural TB is otherwise mainly medical. The concomitant administration of oral steroids may lead to a more rapid resolution of the symptoms.^[34]

Spontaneous pneumothorax and pyopneumothorax

Tuberculosis (TB) is a long-recognized and well-documented cause of secondary spontaneous pneumothorax with an incidence of approximately 5%. Rupture of a cavity into the pleural space is the commonest mechanism for spontaneous pneumothorax in TB. At other times, a pneumatocele may rupture into the pleural space. Spontaneous pneumothorax if left unattended to can lead to tension pneumothorax which is an acute and life-threatening state. Fortunately, response to pleural drainage combined with ATT is as high as 85%.

The pathology in pyopneumothorax is that pleural infection results from rupture of subpleural caseous lesions with concurrent formation of a bronchopleural fisutla. Tube thoracostomy is the indicated treatment, along with appropriate ATT and antibiotics for other infections. In spite of the measures taken, if the disease progresses, closure of BPF is undertaken.

Empyema thoracis

TB has been found to be the cause of empyema in approximately 65% of cases in studies reported from high prevalence regions of the world.^[35] TB empyema carries a worse prognosis when compared to nontubercular empyema. Chronicity of the disease, presence of fibrocavitary lesions, high bacterial load, bronchopleural fistula (BPF), and requirement for complicated surgeries in a lung with compromised function influence the outcome.

Conservative measures in the form of Anti-TB treatment (ATT) alone cannot achieve a cure in tuberculous empyema. External drainage of pleural pus has to be done [Figure 9]. Superimposed infection of this pus by other pyogenic infections may complicate the pathology further and prolong the treatment, as well as increase the cost, in the form of expensive high end antibiotics. Thus therapy for tubercular empyema is aimed at prompt drainage, appropriate antitubercular treatment regimen, and addressing secondary infection in the pleural space.

Figure 9: X-ray Chest (PA view) of a patient with empyema thoracis of left pleural cavity.

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Patients having volumes of pus less than 200 ml and without any evidence of bronchopleural fistula maybe managed by therapeutic pus aspiration. Massive pleural collections and presence of bronchopleural fistula mandates tube thoracostomy. This is covered with appropriate anti-TB treatment for a minimum period of 6 months. The intercostal tube maybe retained insitu for 8 to 16 weeks with nearly half of the patients having complete resolution and achieving AFB conversion.

Rarely, an intrathoracic empyema bursts through the parietal pleura and collects in the extrathoracic soft tissues [Figure 10] and [Figure 11]. This clinical entity is called empyema necessitatis. As long as there is no air fluid level, tube thoracostomy with negative suction suffices.

Figure 10: Chest X-ray (PA view) of both intra and extrathoracic collections.

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Figure 11: CT Thorax – arrow indicates possible communication path between intrathoracic and extrathoracic collections as well as a trapped lung.

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Despite ATT, steroids and drainage, in nearly half of the patients with empyema, fibrothorax sets in due to extraprenchymal restriction resulting in thickening of visceral pleura, trapping of lung, and failure of lung to expand [Figure 11]. Such situations call for surgical intervention.

Decortication (stripping of visceral pleura) or empyemectomy reduces morbidity and mortality when the pleural peel has been present for more than 4-6 weeks, symptoms are disabling and radiologically the lung is trapped. After decortication, rarely residual pleural space requires muscle plombage or thoracoplasty.

Many studies now recommend performing thoracic surgeries early in cases of empyema. Results are found to be similar to those operated at a later stage, thereby decreasing both morbidity and cost.^{[36],[37],[38]} The mortality from empyema ranges 8–11%.^[39],[40]

Bronchopleural fistula

Bronchopleural fistula (BPF) is not infrequently found in TB. Rupture of a tuberculous pulmonary cavity into the pleural space or erosion into the lung by tuberculous empyema results in BPF [Figure 12].

Figure 12: Rupture of a cavity in the upper lobe of left lung leading to bronchopleural fistula.

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If left untreated, BPF gradually emaciates the patient and ultimately leads to death. It may also present as an emergency in the form of tension pneumothorax.

The first line of management of BPF is tube drainage and antibiotic therapy. Susequently, when the patient has been stabilised, infection is under control, adequate ATT has been received, a permanent solution can be offered as in repair of the fistula.

In patients with persistent empyema, open drainage by way of a thoracic window is an alternative. Formation of adhesions with thickened pleura prevents the lung from expanding and the patient can be discharged with little or no further compromise in lung function [Figure 13].

Figure 13: A patient in whom a thoracic window has been created in the right chest wall.

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In elderly patients with chronic sepsis and in patients with AIDS, where surgery is not an option, thoracic window is a convenient method to conservatively manage these patients. This permits patients to be free of cumbersome tubes and bottles and return to rehabilitation and possible productive life.

Solitary pulmonary nodule

Pulmonary TB lesions manifests in various forms depending on the host's reaction to the disease. It ranges from a simple granuloma, known as tuberculoma to a cavity with parenchymal involvement [Figure 14].

Figure 14: Chest X-ray (PA view) depicting tuberculoma at the apex of lung.

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Tuberculoma appears as a pulmonary nodule at the periphery of the lung on a chest roentgenogram. They represent 15% of all solitary pulmonary nodules.

Tuberculomas accumulate F18 fluorodeoxyglucose (FDG) during positron emission tomography (PET) because of granulomatous inflammation causing increased glucose metabolism. This is often confused with pulmonary tumors.

Lai et al. found that transbronchial needle aspirations and brushings were diagnostic in 55% of patients with tuberculomas and in 70% of patients with malignancies.^[41] A specific diagnosis of benign disease is definitely helpful but an inconclusive report should without any hesitation lead to an excisional biopsy. In these specimens, M. tuberculosis can be isolated in approximately 85% of the cases.

The diagnostic value of transbronchial lung biopsy in patients with a miliary TB pattern ranges between 30% and 58% or 64% and 90% depending on inclusion criteria.^[42] Percutaneous biopsy of parenchymal lung lesions shows a poorer performance, with 20–55% of diagnostic yield.^[43] Surgical lung biopsy is therefore required for diagnosis in a set of patients suspected of having TB.

Chronic airway obstruction caused by broncholithiasis, strictures, or tuberculomas can result in the formation of Pulmonary Mucoceles. They mimic malignancy on Chest X-Ray as they are seen as solitary masses. CT Scan is a valuable tool in defining the cystic element of the mucocele. Surgical resection removes the lesion in its entirety and confirms the diagnosis.

Mediastinal adenopathy of unknown etiology

Of the many presentations of extrapulmonary tuberculosis, involvement of mediastinal lymph nodes is one of them [Figure 15]. Although the incidence of tuberculous lymphadenopathy in the mediastinum is lower than that of the cervical region, it is not uncommon. Sayar et al. reported a series of 19 patients with no parenchymal abnormalities who underwent mediastinoscopy and TB was confirmed in 16 of them.^[44]

Figure 15: CT scan demonstrating mediastinal lymph nodes with characteristic central breakdown.

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Needle techniques, including EBUS (endobronchial ultrasound) have a sensitivity of about 80% and a very good specificity. On CTguided transthoracic core biopsy, the diagnosis of TB can be established to a considerable degree with bacteriological confirmation.

However, with the alarming increase in the incidence of MDR-TB, mediastinoscopy, and thoracoscopic biopsies are alternative methods that can be used to obtain sufficient tissue not only for diagnosis but also for culture and sensitivity tests. Surgical removal of entire nodes is indicated only when complications arise.

Pachypleuritis or pericarditis with respiratory and vascular insufficiency

Pachypleuritis is the term for inflammation of the pleura with gross thickening of the membrane which may become as thick as 10 to 15 mms especially in patients with protracted illness. Thickness of normal pleura is 1 to 2 mm. Pachypleuritis is a sequela of PTB and leads to severe fibrothorax and deformity of the chest on the affected side causing severe pulmonary restriction. Treatment lies in total pleurectomy.

In 1-2% of cases of PTB, constriction of the heart secondary to pericardial inflammation occurs. Impaired left sided diastolic filling occurs because the pressure gradient between the pulmonary veins and the left atrium is decreased. Because of severe restriction, function of the left ventricle is affected leading to diminished cardiac output.

Corticosteroids maybe useful in addition to ATT in the management of constrictive pericarditis. If the desired response is not obtained, pericardiectomy is considered.

Cold abscess and osteomyelitis of the chest wall

Tuberculous abscesses are located on the sternum and along the ribs. Except for their external appearance, they are asymptomatic and the skin overlying exhibits normal temperature, giving it the name – cold abscess [Figure 16]. The underlying bone or cartilage show signs of destruction. MTB reaches the chest wall directly from the neighboring lung which harbors the bacilli or via the lymphatic supply.

Figure 16: CT thorax showing lesion in the anterior chest wall in a patient with pulmonary TB.

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Surgical debridement including resection of the necrotic ribs, cartilages, and visible adenopathies becomes necessary when there is no adequate response to ATT. This helps in not only confirming the diagnosis but also in procuring representative tissue for drug sensitivity. Post operative chemotherapy is continued for a minimum of 6 to 9 months. Thereafter recurrence is rare.

Previous incomplete surgery

The cardinal principles in surgery for TB are to remove all gross disease and undertake lung resection only in patients who are sputum negative for AFB. MTB can remain active despite appropriate sensitivity and compliance with drug regimes. Although, having taken all measures, complications such as BPF and tuberculous effusions are encountered. This has been linked to persistent or reactivated disease due to leaving of enough tissue for adequate pulmonary function.

Other sites of postoperative recurrence that may require surgical re-intervention include the pericardium and lymph nodes.

Sinus tracts in the neck are seen in tuberculous adenitis when resection has not been complete. In toto excision is advised for biopsy of these nodes followed by adequate long-term medical therapy.

Thoracoplasty

This involves the resection of one or more ribs to obliterate the pleural cavity and to collapse the diseased lung. Following thoracoplasty, some patients present with rapidly expanding chest wall. This is usually a chronic expanding hematoma and is blood engulfed by dense fibrous tissue.

Delayed complications of plombage

In the early part of the 20th century, thoracoplasty and plombage was the standard treatment of TB. Lucite balls were the most preferred for plombage. These spheres were made of translucent methyl methacrylate. They could be placed in the thoracic cage in a single sitting, could be done on sick patients, and was associated with less physical deformity than thoracoplasty [Figure 17].

Figure 17: Patient with thoracoplasty on the right chest and plombage with Lucite balls on the left chest.

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Lucite balls tend to migrate, either into the mediastinum and compress mediastinal structures, erode into the lung or under the skin. Malignant changes, bleeding and superinfection are known complications.

Another entity is oleothorax where the material used for plombage was made of paraffin, bismuth, and mineral oil. Pleurocutaneous fistula or bronchopleural fistula were known to occur following their use.

Management of this complication requires removal of the foreign bodies and rest of the treatment is similar to that of empyema.

Lung resection in HIV co-infected patients

In patients with TB in Durban, 69.8% were found to have HIV ^[45]. The CD4 count and serum albumin levels in this group require assessment. Patients who have a CD4 count <400/mm ³ are treated with ARVs for at least 3 months prior to surgery. The viral load should be undetectable at the time of surgery. If their albumin levels are <30 g/dl, they are advised nutritional supplementation and surgery is considered only after these levels are attained.

Postoperative Management

The short and longterm outcomes of surgery largely depend on the meticulous postoperative management of TB patients, beginning in the intensive care unit immediately after the operation.

This includes:

Using proper analgesia, including thoracic epidural wherever possible;
Carrying out physiotherapy and respiratory exercises, including incentive spirometry;
Carrying out diagnostic and/or curative bronchoscopies if needed;
Removal of chest drains when there is no air leak and drainage is preferably <100 ml/day. However, in postpneumonectomy patients the criteria are different. A clamp is placed on the chest drain and no suction applied. The clamp is released at intervals to watch for bleeding. If the drainage is >200 ml for 2–4 hours, the need for reexploration arises. The drain is removed if there is no concern of bleeding or air leak the following day
After lung resections, watching carefully for the early and late development of postoperative complications, such as air leaks, bronchopleural fistulas, residual pleural space and pleural empyema, and undertaking treatment procedures as necessary

Anti-Tb Chemotherapy Following Surgery

Patients are advised to continue their preoperative anti-TB chemotherapy regimen soon after surgery. Subsequent alterations in medication are made depending on the bacteriological results of the resected lung tissue. A full course of ATT should be strictly adhered to following surgical resection. Sputum conversion occurs in most patients soon after surgery. Thus the date of surgery may be considered the date of culture conversion. This continued medical therapy addresses scattered nodular lesions, and tiny cavities which may be left behind at the time of surgery.

The following durations of anti-TB chemotherapy are recommended, depending on whether patients are culturepositive or culturenegative at the time of surgery and the type of TB involved:

Culturepositive patients at the time of surgery:
With susceptible TB, 6 months after culture conversion
With MDR-TB, at least 18 months after culture conversion
With XDR-TB, at least 24 months after culture conversion;
Culturenegative patients at the time of surgery who have previously completed ATT:
With susceptible TB, at least six months after surgery
With MDR/XDR-TB, six to eight months after surgery

Video-Assisted Thoracoscopic Surgery

Videoassisted thoracoscopic surgery (VATS) was first reported in 1992. The advantages of thoracoscopy are the amplifying action and deep illumination effect of the camera. Further, in addition to the cosmetic appearance, pain is minimal as there is little injury to the ribs, muscles and subcutaneous tissues.

In expert hands, VATS therapeutic resection can be safely performed in selected patients with pulmonary TB with satisfactory results. Technical contraindications for thoracoscopy are incompleteness of interlobar fissures, solid pleural symphysis and dense fibrovascular adhesions.^[46] However, in an emergency setting of massive hemoptysis VATS has no role; instead, a thoracotomy is to be performed.

Measures to Improve Outcome

A proper preoperative evaluation and optimization of the patient's status is essential, unless there is an emergency, such as massive hemoptysis or tension pneumothorax. The nutritional status of the patient is of prime importance as many could be severely malnourished due to the chronicity of the disease. The feasibility of resection must be carefully evaluated with particular attention to co-morbidities.

Bronchoscopy is mandatory to account for EBTB as its presence could increase the risk of bronchial stump rupture leading to a disastrous bronchopleural fistula, especially following pneumonectomy.

In patients with chronic pulmonary TB, vascular pleural adhesions are common due to systemic-to-pulmonary neovascularization. Release of the lung is challenging and is accompanied with significant blood loss. Owing to the granulomatous process the lung is densely adherent to the vascular structures making dissection laborious.

Bronchopleural fistula is a serious complication of surgery for TB, and is treated first with tube thoracostomy. Attempts to close the fistula preferably should not be made until sputum and pleural cultures have tested negative. On occasion, thoracoplasty may be a useful adjunct to reduce the size of the pleural cavity occupied by a small lung or to treat a BPF.

Surgery is recommended for cases with major residual pleural thickenings.

Sputum positivity at the time of surgery plays a major role in relapse of disease, development of post operative BPF and empyema. Resected specimen harboring tubercle bacilli also carries similar risks. Needless to say, inadequate primary medical therapy too is a cause of relapse. Pneumonectomy offers the best conversion rate and scores over both lobectomy and segmentectomy, however it carries more morbidity. However a healthy balance needs to be struck as maximal disease free parenchyma needs to be preserved in MDR-TB due to the high possiblity of relapse.

The mortality rate following lobectomy is 2–3% and pneumonectomy is 7–8% and surgery for empyema too has its share of complications of about 8–11%^[47]. The postoperative complications of surgeries is 9–26%, the most common being persistent air leakage (40%).^[48]

Conclusions

Surgery has an unquestionable role in the treatment of pulmonary tuberculosis. It is a valuable adjunct to medical therapy. A diagnostic surgical approach is recommended when pleural effusion occurs without any radiologic signs or established cause. VATS or mediastinoscopy with ex tempore histological examination may be helpful to distinguish between malignant and TB lesions. In proper indications and combined with chemotherapy, surgery achieves sputum conversion rates of more than 90%. Wherever possible in proved cases of TB, it is wise to put the knife on the patient only after 3 months of ATT coverage. This is to be followed up with drug sensitive medications for the prescribed duration.

Surgery aims to eliminate or decrease the burden of bacilli in infected patients as well as to treat the sequelae of scarring caused by healing of the disease process. It is next to impossible to sterilize cavities or destroyed lung because the disease maybe too far advanced or medications fail to penetrate the wall of the lesions. Surgery would also benefit patients who have extreme patterns of drug resistance with similar pathology.

Other common indication for surgery is massive hemoptysis in a destroyed lung because of infection, cavity, aspergilloma or bronchiectasis.

Successful treatment of TB depends on prompt diagnosis and proper medical therapy. Sequelae of TB forms the major chunk of patients requiring surgery. The increase in the number of new TB cases and the number of patients with MDR-TB is the emerging challenge for medical providers. When patients fail medical therapy or are at high risk to do so, surgery is a very effective tool in the management of this complex problem. Relevant indications, appropriate timing of referrals and proper selection of patients are crucial to the outcome of surgery in TB.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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