Interactive Cardiovascular and Thoracic Surgery 3:547-550(2004)
© 2004 European Association of Cardio-Thoracic Surgery
Institutional report - Thoracic general |
Cryosurgery for the treatment of benign tracheo-bronchial lesions
Narain Moorjani,
Julia E. Beeson,
Joanna M. Evans and
M. Omar Maiwand*
Department of Cryoresearch, Harefield Hospital, Middlesex, UB9 6JH, UK
* Corresponding author. Tel.: +44-1895-828-558; fax: +44-1895-828-528
cryotherapy{at}rbh.nthames.nhs.uk
Received January 28, 2004;
received in revised form May 11, 2004;
accepted May 28, 2004
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Abstract
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Although cryosurgery has been shown to be effective in managing advanced malignant bronchial tumours, there is very little in the literature describing its use with benign lesions. In this study, we retrospectively assessed the effectiveness of cryosurgery in the management of non-malignant endobronchial lesions. Between 1995 and 1999, 20 patients with benign tumours and non-neoplastic lesions of the tracheo-bronchial tree were treated with endobronchial cryosurgery. The procedures were performed under general anaesthesia, using specifically designed cryoprobes. The patients were assessed clinically, radiologically and by respiratory function tests before and after each cryotreatment. Over the 5-year period, each patient received a mean 2.6 (range 1–9) cryo-applications, with no peri-operative deaths. All patients described a subjective improvement in at least one of their symptoms (cough, haemoptysis, stridor, chest pain or dyspnoea) following cryosurgery and 75% of patients improved in all symptoms. Following surgery, both forced expiratory volume in 1 s (2.23±0.27 vs. 1.98±0.25 l,  ) and forced vital capacity (2.86±0.33 vs. 2.62±0.30 l,  ) improved significantly. In conclusion, cryosurgery can provide effective symptomatic control in patients with non-malignant endobronchial lesions, the majority of whom are discharged on the day of surgery. It affords an easy to perform, safe procedure, which should be considered for patients with benign endobronchial lesions.
Key Words: Endobronchial cryosurgery; Benign tracheobronchial lesions
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1. Introduction
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Although benign lesions of the tracheobronchial tree are relatively rare, they can cause distressing respiratory symptoms, including dyspnoea and stridor [1]. In managing these patients, it is important to rule out an underlying malignant cause and to remove the lesion before it causes distal pulmonary disease. The main principle of treatment is to eradicate the lesion whilst conserving lung parenchyma and the choice of therapy depends on the exact nature, site and extent of the lesion, propensity for recurrence and urgency of treatment required.
Surgical resection is usually undertaken when the lesion has extended beyond the bronchial lumen or if there is a high likelihood of recurrence. With purely endobronchial lesions, a number of endoscopic treatment modalities are also available, which avoid the morbidity and mortality associated with thoracotomy and pulmonary resection. These include bronchoscopic curettage, Nd-YAG laser, electrocautery and cryosurgery. The choice between these endobronchial therapies varies from centre to centre depending on the equipment available and the preferences and experience of the individual surgeon or pulmonologist.
Cryosurgery has been shown to be effective in treating advanced malignant lesions, resulting in improved symptom control, respiratory function and performance status [2]. Its use in the treatment of granulation tissue following lung and heart-lung transplantation has been reported previously [3] but there is very little other published literature describing the use of cryosurgery in the management of benign lesions of the respiratory tree. In this study, we have retrospectively looked at patients referred with non-malignant pathologies, including benign tumours and non-neoplastic lesions, in order to assess the effectiveness of cryosurgery in the management of benign endobronchial lesions.
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2. Patients and methods
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Between January 1995 and December 1999, 20 patients with non-malignant endotracheal lesions were treated with cryosurgery. The mean age of the patients was 63.7 years (range 26–80) with a male to female ratio 1.22:1. Fig. 1 shows the anatomical location of the lesions encountered. The patients were assessed clinically, radiologically, and by respiratory function tests before and after each cryotreatment. All patients had a pre-operative CT scan to assess for any extra-lumenal component of the lesion. Using validated symptom scores, evaluation was carried out for dyspnoea, haemoptysis, cough, stridor and chest pain. Respiratory function tests, including forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), were measured using a Microlab turbine spirometer.
Cryosurgery was performed under general anaesthesia using a rigid Storz bronchoscope and oxygenation maintained with Venturi positive-pressure ventilation via a Sanders injector. Prior to each cryotreatment, tissue samples were taken for histological examination. Biopsy results included tracheobroncheopathia-osteochondroplastica 4, sarcoidosis 4, polyps 3, papilloma 2, non-transplant granulation tissue 2, amyloidosis 1, lipoma 1, leiomyoma 1, post-intubation tracheal stenosis 1 and haemangioma 1. The distal tip of the bronchoscope was then placed about 0.5 cm above the lesion and the appropriate cryoprobe (straight, right-angled or flexible—Spembly, UK) inserted through the bronchoscope. The selection of probe diameter, 5 or 2.2 mm, was based on the size and position of the lesion. The 2.2 mm probe was used for peripheral smaller lesions, whereas the 5 mm probe was used for larger, central tumours. These probes employ the Joule–Thomson principle, whereby nitrous oxide is released at high pressure ( 5000kPa) and allowed to expand rapidly within the bulb of the probe, achieving temperatures of about –70 °C at the probe tip. The probe was applied to the lesion for 3 min and then allowed to thaw before removal. All areas of the lesion were treated to achieve adequate destruction. The use of a large rigid bronchoscope enabled a small suction catheter to be placed next to the site of treatment to remove blood and secretions throughout the procedure. Any necrotic material was removed with forceps before subsequent cryoapplications. In patients with large lesions, initial debulking was carried out using the biopsy forceps. If the lesion was particularly vascular, an initial freeze was induced to reduce bleeding. Further application of the cryoprobe to the pedicle or base ensured effective cryodestruction of the lesion. For patients with multiple lesions in both lungs, only one lung was treated at each session.
Bleeding from the site of biopsy or cryosurgery occurred occasionally and was managed by topical application of adrenaline (1:1000). The majority of the patients were discharged on the same day of the operation. Two weeks later, all patients underwent a biopsy and a second course of cryosurgery. Subsequent cryotreatments were carried out depending on clinical and bronchoscopic findings.
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3. Results
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Over the 5-year period, 20 patients received a mean of 2.6 (range 1–9) cryo-applications, during which time there were no peri-operative deaths. Complications were rare, with post-operative haemoptysis encountered in two patients. This resolved in both cases, within 24 h of the initial procedure. All patients described a subjective improvement in at least one of their symptoms (cough, haemoptysis, stridor, chest pain or dyspnoea, Table 1) post cryosurgery and 75% of patients improved in all symptoms.
Following cryosurgery, both FEV1 (mean 2.23±0.27 vs. 1.98±0.25 l, ) and FVC (mean 2.86±0.33 vs. 2.62±0.30 l, ) showed significant improvement (paired student  -test, Fig. 2). Anatomical results after cryosurgery were judged excellent (complete removal of lesion) in 15 patients and good (some residual tissue) in 5 patients (Fig. 3). There were no cases of bronchial perforation. At a mean follow-up of 6.5 years, 5 of the 20 patients died of causes not related to their cryosurgery or underlying benign endo-bronchial lesions. Six patients required further cryosurgery to their endobronchial lesions, including one patient, with amyloidosis, who required nine treatments in total for recurrent disease. The remaining patients maintained their improved symptom status over the follow-up period.
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Fig. 3 Bronchoscopic images illustrating benign endobronchial lesions (top panel) and restoration of luminal patency following cryodestruction of lesions (bottom panel). A=Lipoma, B=Benign endobronchial polyp and C=Bronchial amyloidosis.
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4. Discussion
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The analgesic and anti-inflammatory properties of low temperatures have been known for several centuries, but therapeutic applications of freezing to induce tissue destruction originate from work carried out by James Arnott in 1851 [4]. The use of cryosurgery in the tracheobronchial tree began in the 1980's, with the development of specially designed cryoprobes [5]. These probes have been used to good effect in treating advanced bronchial carcinoma [2], but there is very little in the published literature describing their use in the management of non-malignant endobronchial lesions.
Due to their location, benign endobronchial lesions can cause distressing symptoms and if left untreated may induce distal pulmonary obstruction. Cryosurgery effects tissue destruction to these lesions by inducing extracellular ice crystal formation, causing hypertonicity and withdrawal of intracellular water [6,7]. This increase in intracellular solute concentration and change in pH to 4 causes damage to the cellular proteins, lipoproteins and enzymes. The cryosensitivity of tissues is directly related to their free water content. This makes cryosurgery ideal for treating lesions originating from the mucosa of the bronchial tree, as the bronchial cartilage has a low free water content making it relatively cryoresistant and hence reducing the incidence of bronchial wall perforation. In response to freezing, the respiratory mucosa undergoes necrosis, followed by progressive epithelial regeneration, initially as cuboidal epithelium and then after 30 days as normal respiratory pseudo-stratified ciliated columnar epithelium [8,9]. The healing process occurs without inducing fibrosis or stricture formation. This was confirmed in our study, where there were no signs of pneumothorax or pneumomediastinum secondary to bronchial wall perforation or any bronchoscopic evidence of stricture formation. In the patients with tracheobroncheopathia-osteochondroplastica, only two obtained excellent anatiomical clearance of the lesion. This may be in part due to the fact that these lesions contain ossified or cartilaginous nodules in the submucosa, making them less cryosensitive. In view of this, these patients required more cryotreatments to obtain symptomatic improvement. As regards patients with sarcoidosis, endobronchial therapy was employed when the disease process extended into the bronchial tree, causing symptoms.
Freezing also has an effect on small blood vessels due to the formation ice crystals within the vessels. Below –20 °C, showers of micro-cryoemboli form and deposit on the vessel wall leading to obstruction of flow, ischaemia and eventually tissue necrosis [10]. Low temperature also induces arteriolar vasoconstriction and increased blood viscosity. All these factors have a beneficial effect in controlling surface bleeding during the procedure and reducing the incidence of post-operative haemorrhage. In this study, only two patients encountered post-operative haemoptysis, which in both cases resolved within 24 h. The main disadvantage of cryosurgery, however, is that often more than one treatment session is required for complete removal of the lesion. Also, it is not ideal in an emergency situation, as it has a relatively slow mechanism of action, where tissue necrosis and sloughing can take up to a week to occur [11]. In view of this, cryosurgery can be used as a therapeutic modality that compliments other endobronchial therapies in the management of benign bronchial lesions.
In this study, we have shown cryosurgery to be effective in the management of a wide range of both benign tumours and non-neoplastic lesions of the tracheo-bronchial tree. Overall, 100% of patients described a subjective improvement in one or more of their symptoms associated with a significant improvement in respiratory function. The majority of these patients were discharged on the day of surgery with minimal or no cryosurgery related complications. In conclusion, cryosurgery should be considered as a safe and easy to perform procedure in the management of benign endobronchial lesions.
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Footnotes
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Presented at 98th International Conference of the American Thoracic Society, Atlanta, USA, May 2002.
doi:10.1016/j.icvts.2004.05.008
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Abstract
1. Introduction
