Author: Ricardo Isoro
Enrique Tornú Hospital. Buenos Aires. Argentina
Summary
Objective
Establish the frequency of complications in the different pathologies, differentiate them according to the type of stent used and relate them to the time of permanence of the different prostheses. Determine the averages of permanence of the prostheses in the healing of the benign stenosis.
Method and Material
Retrospective analysis of 388 reports of interventional bronchoscopy performed to treat 300 patients with total or partial obstruction of the airway, due to benign or malignant lesions. The therapeutic success was evaluated according to its capacity to restore the tracheobronchial lumen.
Results
300 patients with partial or total obstruction of the airway, 115 women, mean age 52 ± 16.26, range 14-86 years. 388 therapeutic procedures were performed and airway patency was achieved in 96.33% of the cases. A total of 318 prostheses were used. With a high general tolerance to stents of 99.68% and 100% for all-metal silicone prostheses. In 126 patients with classical benign stenosis post-intubation, 107 prostheses were used in 122 tracheal stenosis and 4 bronchial stenosis. The cure rate was 44%. In those who used prostheses, these remained installed during a period of 21.2 ± 13.30 months for cases cured. The most common complication in the treatment of benign stenosis was stent migration: 13%, higher in straight silicone prostheses (85.7%) compared to stenotic prostheses (14.3%). The development of granulomas (9.24%) was more frequent with the use of straight models (60%).
The second group includes 174 patients with conditions “not benign stenosis”, which contains 110 cases of carcinoma, 10 endobronchial metastases of extra-pulmonary tumors identified and the remaining, correspond to various etiologies. 211 prostheses were used in this group, resulting in an average of 1.2 ± 0.46 stent per patient. The complication rate was 6.32%, with hemorrhage in the first place. Mortality due to the treatment, in the 388 procedures performed, was 0.25%.
Conclusions
Rigid bronchoscopy shows its ability to restore clearance in situations of airway obstruction, with a success rate of more than 96% and very low mortality. Silicone prostheses with designs of the “stenotic” type are decidedly more effective than straight models, for the treatment of benign tracheal stenosis. Although the residence time necessary for the healing of benign stenosis has not yet been defined, this period can be around 22 months when a stenotic model is used, but greater when a straight stent is applied.
Introduction
Endoscopic treatment of lesions that produce occlusion or sub-occlusion of different magnitude in the trachea, source bronchi or in some lobular, has achieved sufficient diffusion within the international medical community to the point where its realization is well established (1). The indication to apply a method that can recover the pulmonary ventilation suspended by the presence of an obstructive lesion appears immediately in the bronchoscopists. However, it has been limited to those cases in which an open-pit extirpation treatment is not possible. The use of silicone stent is another widely used resource in order to provide additional support to the airway after treatment and to prolong its effectiveness. Thus, the endo-surgical treatment has been simplified and interventional physicians have accumulated experience in its implementation, a task that has been shown to provide benefits that are proportionate to the magnitude of the difficulties overcome during its implementation (2-3).
Patients and method
The data were obtained from reports of interventional bronchoscopy corresponding to 388 procedures performed to treat 300 patients, with benign and malignant conditions that occluded partially or completely, the great airway.
The interventionism applied to patients was performed in one or several sessions. None of them was amenable to resection treatment by conventional surgery and all were subjected to a flexible bronchoscopy in order to evaluate the characteristics of the lesion. Thus, the indication of the procedure was maintained considering the possibility of lung re-expansion and the clinical presumption of improving dyspnea with treatment, in all cases of malignant disease and in benign stenosis that reduced the clearance by 50% or more. This subjective evaluation was established by comparing the diameter in the affected area with that existing in the healthy airway near the lesion; and with the reference of the known caliber of the bronchoscope in use.
The patients underwent treatment with rigid or flexible bronchoscope, under general anesthesia and muscle relaxation, in the operating room and under continuous control of cardiac and respiratory function. They received 2 grams of intravenous cephalothin in rapid injection minutes before the procedure.
The treatments were carried out by two experienced pulmonologists, dedicated exclusively to bronchoscopy.
For recanalization of the airway, dilatation maneuvers were performed with spark plugs of increasing diameter, balloon and / or rigid bronchoscope. An electrocautery was also utilized to make cuts in some benign stenosis and thermocoagulation with tissue vaporization in the malignant lesions. The cases, for the most part, were treated using a rigid bronchoscope of interchangeable tubes of different calibers, set of optics, prosthesis introducers, and tweezers suitable for mobilization, probes and tapes for application of T tubes of the Montgomery type. In a few cases, the treatment was performed or completed with a flexible Olympus bronchoscope BF1T30.
The application of different models and dimensions of silicone stents for the airway was arranged, although dynamic and self-expanding stents were also used. It was accepted as “good tolerance” to the stent, to the absence of clinical manifestations that motivated its removal.
The result was considered by virtue of having achieved sufficient recovery of lumen in the airway.
In benign strictures, it was established to determine as satisfactory tracheal or bronchial recanalization, all those in which the clearance of the affected area had reached 75% or more of the normal caliber for that case, after finishing its treatment.
Complications were considered to all those that occurred during or after treatment when they were directly linked to it. Thus, hemorrhage, desaturation, with a decrease greater than 4%, rupture of the airway wall, restenosis, migration of the stent, development of granulomas and colonization of the prosthesis are recorded. Complications were considered to all those that occurred during or after treatment when they were directly linked to it. Thus, hemorrhage, desaturation, with a decrease greater than 4%, rupture of the airway wall, restenosis, migration of the stent, development of granulomas and colonization of the prosthesis are recorded.
The cases of death were recorded when this was due to the treatment instituted or as a direct consequence of it, during its application or subsequent to it.
It was established to consider “cured” all those patients treated for benign stenosis, and after removing the stent when one was implanted, they were free of recurrence and with a clearance in the airway, greater than they had before the treatment and that at the same time they did not present dyspnea or stridor when performing their usual daily tasks.
Results
388 procedures were performed in 300 patients (1.29 procedures per patient).
The procedures performed with rigid bronchoscope totaled 383 (98.7%), while in 5 cases the flexible bronchoscope (1.3%) was used. In 11 cases out of 300, recovery of the bronchial lumen was not possible and was considered as failure of the procedure. All of them corresponded to patients diagnosed with carcinoma, and the endobronchial tumor lesion was also intramural and infiltrating. The recanalization of the airway was possible in 289 patients (96.33%). Table A.
Of the total, 115 were women (38.33%) and 185 men (61.66%). The ages go from 14 to 86 years. The mean age was 52 ± 16.26 years and 311 silicone prostheses (97.8%), a polyflex® self-expanding stent and 6 dynamic Freitag prostheses were used for the treatment, thus totaling 318 devices. Thus, 126 benign stenosis were treated in the trachea and bronchi (42%), and 174 conditions were “non-benign stenosis” (58%), Tables B-C. This last group includes 110 cases of carcinomas that include 10 metastases of extra-pulmonary primary tumors.
Regarding the use of prostheses by pathology, the 126 benign stenosis required 107 stents for their treatment (0.84 stent per patient).
For the group of “no benign stenosis” lesions, of 174 cases, 211 devices were used. (1.2 ± 4.6 prostheses per patient). Table D.
In the 388 procedures, complications occurred in 44 of them (11.34%), which will be detailed below.
Benign stenosis group
Of the 126 cases with benign stenosis, 122 affected the trachea (96.82%) and 4, (3.18%) to the source bronchi. 100 of the total, (79.40%) were post-intubation stenosis. Of the remaining 26, 4 occurred at the site of a previous tracheostomy, 4 were recurrent at the end-to-end anastomosis site of open surgery performed previously for the resection of the tracheal stenosis, 4 after rupture of the trachea, one after severe trauma to the larynx and another due to aortic aneurysm. The cause could not be determined in 9 cases.
Four benign stenotic lesions were found in the bronchial sources, two were sequelae of pulmonary tuberculosis, one after traumatic bronchial lesion and the other with bronchial anesthetic intubation.
The tracheal stenosis were of complex conformation in 113 cases, (89.7%) simple in 11 (8.7%), and 2 were subglottic (1.6%). Table E.
The controlled follow-up of the patients was extremely low. 88 cases (69.8%) did not attend the scheduled appointments. Although many cases of this group are still under treatment, a large number have lost contact with the endoscopy service totally; also including those who had had the stent removed because they considered that the enough implanted time had ended.
Of the remaining 38, 17 cases reached cure (44.7%) and 21 required a stent permanently, some additional treatment, such as definitive tracheotomy, or still under treatment. Table F.
The minimum permanence of the prosthesis was one month and the maximum known for 106 months, with an average general stay of 19.6 months. Table G.
In the group of 17 cured patients, 11 prostheses were used. Each patient received a stent and 6 did not require any. The shorter time of permanence recorded is 2 months, for a “T” tube, but in the case of classical silicone straight stents, the lower record indicates 10 months and the maximum 36, with an average permanence for healing of 21, 2 months. Table H.
The 11 prostheses used by the cured patients were all silicone devices, a classical model in one piece and without metal. Six of them are stenotic, 3 bronchial/tracheal and two tubes in “T”. Tables I-J. Finally, the average number of months that the stent units were installed according to the models was 22.6 months for the stenotic patients, a little more: 28.6 months for the ones using the bronchial/tracheal stent and 6 months for the “T” tubes. Table J.
Complications: complications occurred in 44 of the 388 procedures (11.34%), all performed with a rigid bronchoscope. The five treatments instituted with flexible bronchoscope did not have any complications. The greatest number of them occurred in the group of patients with benign stenosis, with a total of 33 in the 126 cases. The complications observed in the treatment of benign stenoses were mostly related to the 107 prostheses used. Fourteen (13%), were migrations, 6 colonizations (5.6%), development of granulomas in 10 cases (9.24%), mucosal hypersecretion in 2 (1.86%), and a rupture of the posterior wall of the trachea (0.79%). Table K.
The migration and colonization of the prostheses was more common in straight models of silicone and less frequent in designs of the “stenotic” type. Table L.
Regarding the development of granulomas by contact with the sent, occurred in 10 of the 107 prostheses used, have happened on six occasions in which a straight stent had been applied, two with a “T” tube, one with a subglottic stent and another with a stenotic. The general stay time for all these prostheses was 17 months; but individually, the complication was detected on a subglottic stent applied for 36 months, a stent for the same period, and in groups, 3 months for the “T” tubes and finally, the straight stents that generated granulomas had an average stay of 11-75 months. Table M-N.
“Non-benign stenosis” group
The group of patients not included with the benign stenosis is formed by all the cases that presented other invasive lesions of the tracheobronchial lumen or that developed their growth in it, and although it is composed in greater number of bronchial carcinomas, other etiologies were also found in this set, and none of them, as mentioned, can be included in any way with the benign strictures that affect the airway.
Thus, this group includes 174 patients, of whom 38, had the stenosis located in the trachea, 101 in the bronchi and 35 shared both locations. Table O.
In 11 (10%) of the 110 carcinoma cases, reconstruction of the tracheal or bronchial lumen was not possible. Table A.
Regarding the histological type of the lesions, 28 squamous cell carcinomas, 25 adenocarcinomas, 10 small cell carcinomas, 2 giant cell carcinomas and 8 carcinoid tumors were found. Endobronchial metastases totaled 10 cases. In another 13, the endoscopic biopsy identified the carcinoma, but it was not sufficient to establish its histology.
In addition, 1 chondroma, 1 neurofibroma, 11 carcinomas of the esophagus invading the bronchial lumen, tracheal, or both were found; 7 thyroid carcinomas involving the tracheal wall, 4 mediastinal tumors and 1 lymphoma. In one case, the diagnosis was papilloma, in another leiomiosarcoma, 1 granuloma and 2 bronchial amyloidosis. In 45 more cases the diagnosis could not be established by flexible bronchoscopy, being also subjected to endoscopic treatment of unclogging. Squamous cell carcinoma was the most frequent tumor with 25.45% of cases, followed by adenocarcinoma: 22.72% and oat cell (9.09%). Three bronchopleural fistula patients also underwent bronchoscopic treatment in which the fistula was blocked with a solid, cylindrical silicone device. (Table P.) In this group, 211 prostheses were used for 174 patients. (Table D).
In relation to the 10 metastases, 8 of them were from clear cell renal carcinoma, breast tumor and the other colon tumor. Table Q.
Complications occurred in 11 cases (6.32%); headed by hemorrhages that equaled the suction capacity of the aspiration system, 3 in total (1.71%) and that resulted from the treatment of a non-typified carcinoma, an adenocarcinoma and a carcinoid tumor.
Migration of the prosthesis in two cases (1.49%): tracheal adenocarcinoma with stenotic stent in the first and straight stent in a carcinoid tumor, the second. Device colonization (0.54%) implanted in a case of amyloidosis. The list of complications of the present group of lesions “no benign stenosis” continues with a case with intense edema of the mucosa at the end of a dynamic stent (0.54%), reversible cardiac arrest, during the treatment of a tracheal rupture ( 0.54%), a superior vena cava syndrome (0.54%), followed by death at 48 hours, in a patient with adenocarcinoma invading the trachea and both source bronchi (0.54%), atrial fibrillation in a case with adenocarcinoma (0.54%) and a partial pneumothorax in a patient who lacks histopathological diagnosis. Table R. Thus, the mortality determined for this group of 300 patients is 0.33%, and considering the mortality linked to the procedure, it is reduced somewhat more: 0.25%. Table S.
Intolerance to the prosthesis was extremely rare. Only one case was observed in the whole series, which represents 0.33% in relation to the treated patients and somewhat lower, 0.31% if it is considered according to the stents used. Table T-U.
It is a dynamic “Y” prosthesis implanted in a patient with intra-bronchial metastasis of a clear primary renal cell tumor. The intolerance manifested by incoercible cough was attributed to the intimate pressure contact of the proximal end of the prosthesis with the tracheal mucosa adjacent to one of its rings. The stent was shortened and reinstalled without symptomatic relief and had to be removed and replaced.
Discussion
The usefulness of the method is well established and the selection of patients has been widely discussed and published. Thus exposed, the debate on these points would be, depending on its lack of novelty and the even lower contribution of knowledge, monotonous and unnecessary. Observing the frequencies of appearance of inconveniences or the lack of them, considerations arise that are the beginning of this discussion. The series of 300 cases contains a numerous and exclusive group of benign stenosis, mostly tracheal. All of them recovered the caliber of the airway with endoscopic interventionism. Then, the procedure in general was clearly satisfactory, with a success in reaching its purpose of 96.33%.
Having announced electrocautery as the only cutting, vaporization and thermocoagulation device used in this series, its resolutive possibilities are bound to 96.33% of solved cases (4-6). The 3.66% of failures corresponds to 11 cases with carcinoma diagnoses. In this, the procedure fails to find distal clearance to the obstruction of the airway (5) as it happens when the lesions turn out to be intramural and very infiltrating, that is, when this sought-after clearance does not exist.
The overwhelmingly superior use of classic silicone prostheses is due to their simple availability in our environment and, safeguarding their well-known behavioral virtues, their preference is not sustained in the detriment of other types and designs, also efficient (7-9- 10).
The desertion of operated patients is strikingly high. When the cases that are in control or in treatment are added, at the time of making this paper, reach 69.85% of the total of benign stenosis. Thus, better general conclusions could not be obtained about all the points examined here. Likewise, the time in which the stent has remained implanted in the patients has been observed. Few are the reports about the time of permanence of the prosthesis. In the literature reviewed, the devices were removed due to healing, remission of the lesions treated or simply removed after a period considered sufficient for stabilization or cure (11-12), without being known in all, the results of the long therapeutic process. In many cases the device remained implanted throughout the patient’s survival (8). They usually stay in the airway for variable periods, from a few weeks to 24 months or more, depending on the survival of the patient in malignant diseases or the control of their condition. This varies according to the therapeutic preferences of the working groups. There are reports of very long stays, which in some cases have exceeded 4 and 5 years, with good tolerance (13). The removal of the device for other reasons such as its deterioration, modification, decrease or loss of its mechanical qualities or rejection of its components was not observed.
In the series presented, the devices remained installed for a range as wide as 1 to 106 months, depending of course on very different circumstances, such as the individual behavior of each case, its operability, evolution and, precisely, the selected prosthetic element. The “T” tubes are used for a short period, since they usually meet an intermediate “step” in the way of the patient’s therapy, while the stents remain a much longer term, since they try to offer the tracheal or bronchial wall a support during the time required for its consolidation, because it cannot be obtained in a shorter time what only comes with it.
We have examined the period of permanence, relating it to the etiology, and also the permanence of the prostheses in the benign stenosis healed that was, both on average, and considering each prosthesis individually, shorter for the stents of the stenotic model (22, 6 months) than for the straight ones (28.6 months). For this fact of full certainty to acquire true strength, it will be necessary to study a larger group of cases, but it could be pointing to a trend.
Stenotic prostheses also showed less migration. Although this situation is somewhat expected, since it has a profile that tries to mimic the contour of the stenosis, to hamper its displacement which is, moreover, the reason for its design; and with your choice we see our purpose fulfilled. The stenotic stents showed less colonization, without this time we can offer a thorough basis to explain it. The granulomas were present, as they always do. This time they did with a frequency of 9.4%. Granulomas should not appear if the stents were correctly applied, that is, with the middle portion of the prosthesis “fitted” in the stenosis and its ends “floating” in the tracheal lumen.
The “non-benign stenosis” group analysis revealed, in the first place, a greater number of prostheses used (211 units), a cause that is found in the need to use more than one stent per patient and also sometimes more than one procedure. This, in turn, shows, indirectly, that the probable extension of survival allows the malignant disease to progress and thereby resort to obstructing, in the same or different site, the airway, motivating a new intervention.
The majority correspond to bronchopulmonary carcinomas or neighboring organs. Among the latter, the thyroid, with locoregional extension and invasion of the tracheal lumen, circumstance and etiology that in no way modifies the attitude of the bronchoscopists. Eleven cases of carcinoma of the esophagus that, unlike the previous one, injures and bursts through the posterior wall of the trachea or, when its location is lower, involving the left main bronchus once more in its posterior wall, since it is there where the esophageal path intersects with this bronchus. Many times the damage is localized to the left side, passing the esophagus to inhabit the bronchial lumen. It has been very useful for endoscopically realigning the left source bronchus, expelling the esophagus and covering the fistulas that are a frequent companion in this table, using a silicone stent with a smooth wall, since anchors are not necessary now. One of its ends widens in a cone shape and coincides anatomically with the source of the source. The beveled distal end makes simple the entrance maneuver to the bronchus and the introduction of the stent.
Migration of the prosthesis, although less common (11) in malignant conditions, is also possible. We describe here only two migrations (1.49%), in which one of them corresponds to a carcinoid tumor in which an error in the early typing of the lesion, led to the treatment of the obstruction with stent implantation.
Few comments will be made about two fortunately infrequent events, such as stent intolerance, whose reasons were already clearly developed; and death, as a result of the procedure, which in our report was 0.25%. It corresponded to a patient with mediastinal disease due to an adenocarcinoma. Since the mediastinal syndrome makes the rigid bronchoscopy risky for diagnostic purposes, this risk will be reasonably increased when the procedure is also therapeutic. Since the same factors that operate in the first one, will be more influential in the second one, because the time necessary for the intervention will be much higher. Thus, the maneuvers that this entails and the displacement of tissues caused by the rigid bronchoscope, lead to an increase in local inflammation and aggravation of the already compromised venous return to the mediastinum.
This paper intended to be a recount of the results among what happened after the interventionist assistance of a very large group. Notwithstanding it acquired a turn in its sense when the figures are observed that tend to mark a trend that involves the possible relation between the prostheses use and its complications. This is linked to the permanence time and reveals that, at least in this series, it is around 23 months. The casuistry is not enough to grant the title of “good recommendation”. Nevertheless, a timid guiding utility is detailed. The lines of a direction to be followed towards a solution that possesses the magnitude of the effort until now determined to stop, this affection so simple and rebellious at the same time, are thus traced.
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