The expectoration of surgical staples during a fit of coughing after thoracic surgery is an unusual occurrence. We present the case of a postoperative metalloptysis episode after a procedure for recurring pneumothorax, in which a linear endostapler was used, with no staple-line reinforcement.
The patient is a 29-year-old woman who had undergone surgery for right pneumothorax. She came to our consultation reporting fever of 38°C for several days. Chest radiograph revealed a lung consolidation in the apical region of the right hemithorax, and empirical antibiotic therapy was initiated.
30 days after the procedure, computed tomography was ordered due to the persistence of the apical opacity on follow-up radiographs. CT showed evidence of a consolidation in the upper right lobe that coincided with the area of the surgical staple line. Possible diagnoses were pneumonia in the post-surgical area or reaction to a foreign body. After tomography and during a coughing fit, the patient expectorated a chain of surgical staples that was approximately 3cm long. After this episode, the patient's condition progressed favorably, and her infectious symptoms disappeared spontaneously.
After discharge, the patient was followed-up in the outpatient setting and presented improved symptoms and radiology results.
Metalloptysis is defined as the expectoration of metal materials that were previously used for treatment in either the bronchi or lung parenchyma.
In 1999, Aggarwal reported an episode of expulsion of metal fragments from endobronchial prostheses1 used for the treatment of tracheobronchomalacia.
The first cases of metalloptysis originating from the parenchyma were published approximately 10 years ago. In 2001, Waller2 published a series of 3 cases of surgical staple expectoration after lung volume reduction surgery. Furthermore, it was Waller who coined the term metalloptysis to describe the expectoration of metallic materials. Simultaneously, Ahmed3 published a case report involving the expectoration of surgical staples one year after lung volume reduction surgery in a patient who presented recurring lung infection.
Later, Shamji et al.4 presented a new case of metalloptysis and hypothesized that it may have been caused by an inflammatory reaction to the bovine pericardium reinforcement of the staples used in volume reduction surgery and in pulmonary bullectomy. Like Waller and Ahmed, Shamji used an endostapler with bovine pericardium reinforcement; the pathology study of the surgical specimen reported an important inflammatory component. In all the published cases until that time, endostaple-line reinforcement with bovine pericardium was used. This material is widely used as an animal graft in other procedures and had been used as a means to try to reduce postoperative air leak in emphysema patients,5 which prolonged hospitalization and increased morbidity and mortality. It was argued that the presence of bovine pericardium in the lung parenchyma induced an in vivo immunological response that was consistent with a graft-versus-host reaction. In addition to other complications published in the literature,6,7 there is a case of hemoptysis due to pulmonary hematoma surrounding the surgical staple line in a patient with a history of surgery for spontaneous pneumothorax 3 months before, which required resection of the lobe involved.8
Although the reports published to date have been isolated cases of expectoration of a foreign body, Hadley and Rees9 reported a case of metalloptysis with expectoration of a total of 12 surgical staples on several different occasions and at regular intervals. As in previous cases, lung resection was performed with endostaplers reinforced with bovine pericardium. Therefore, they concluded that metalloptysis can be self-limiting or can persist over time.
It is also important to analyze the indications for lung resection surgery in the published cases. The most frequent indication was severe emphysema, involving lung volume reduction surgery. Nonetheless, there were also infectious causes (hemoptysis due to pulmonary aspergilloma9) and mixed causes10 (chronic necrotizing aspergillosis and sarcoidosis).
In spite of everything, certain questions remain unanswered. First of all, only 10 cases have been published worldwide, including our own, and there is no registry for these cases. This suggests that the incidence may be low due to underreporting, especially since it is not uncommon to hear of personal experiences with this sort of cases in surgical groups. Secondly, the immunological process that is responsible for metalloptysis has not been determined. Even though most cases are secondary to severe emphysema, there are also infectious cases and those secondary to collagen diseases. Last of all, and unlike previous reports, staple-line reinforcement with bovine pericardium was not used in our patient, and the time between surgery and metalloptysis was shorter (1month, compared with 4–20 months in the cases reported to date). This raises doubt about the previously hypothesized causes and opens the possibility for other origins or causes, until new theories are developed.2,10
Please cite this article as: Isea Viña J, Simón Adiego C, González Casaurrán G, Peñalver Pascual R, González Aragoneses F. Metaloptisis: ¿un nuevo caso con otra causa? Cir Esp. 2015;93:412–413.
