Reoperations are common following VATS for spontaneous pneumothorax: study of risk factors
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《血管的通路杂志》
Department of Cardiothoracic Surgery, Lund University Hospital, S 222 85, Lund, Sweden
Abstract
Objectives: To identify risk factors for reoperation following surgery for spontaneous pneumothorax. Material and methods: This is a retrospective clinical study conducted on 240 consecutive patients operated on for spontaneous pneumothorax in Lund University Hospital between January 1996 and December 2003. Patient information was gained from medical charts and operation reports. Logistic regression analysis was used to evaluate risk factors. Median follow-up was 54 months. Results: Video-assisted thoracoscopic surgery (VATS) was used in 93% of the patients, where bullectomy with or without pleurodesis/pleurectomy was performed in most cases. Conversion to anterolateral thoracotomy was required in 6 cases (2.3%). Operative mortality (<30 days) was 0.8% (0% after VATS). Altogether 35 patients (13.7%) required a reoperation. Twenty patients were reoperated on within one month from surgery, most often due to prolonged air leakage (n=13, 5.1%) and bleeding (n=6, 2.3%). Fifteen patients (5.8%) were reoperated on because of recurrent pneumothorax, on average 17 months (range 1–39 months) after the primary operation. Significant independent risk factors for reoperation were; young age, operations performed for secondary pneumothorax due to emphysema and recurrent pneumothorax. The risk was also increased in patients where wedge resection was not performed. However, the type of pleurodesis or pleurectomy was not related to increased risk. Conclusions: A considerable number of patients require reoperation after VATS for pneumothorax. Most reoperations are due to prolonged air leakage or recurrent pneumothorax. The risk for reoperation is increased in younger patients, patients operated for recurrent or secondary pneumothorax, and in cases where pulmonary wedge resection is not performed.
Key Words: Pneumothorax; Recurrent pneumothorax; Surgical technique; Reoperations; Risk factors
1. Introduction
Spontaneous pneumothorax (SP) is a relatively common condition affecting mostly young and otherwise healthy individuals. It is most often caused by a rupture of apical subpleural blebs (primary SP) but can also occur in patients with underlying lung diseases, typically COPD or emphysema (secondary SP). Conservative management with needle aspiration or more commonly chest tube drainage remains the standard treatment for the first episode of SP. However, recurrences are frequent and in a long-term perspective 40% or more of the patients treated conservatively eventually require a more definite treatment [1]. This includes instillation of pleural irritants (e.g. talc, tetracyclin) or more frequently surgery, including excision of leaking blebs and pleurodesis. Until a decade ago operations for pneumothorax were performed through thoracotomy. Today most of these operations are performed with a minimal invasive technique using video-assisted thoracoscopic surgery (VATS). In contrast to conservative treatment, recurrence rates following surgery are low, most often in the 1–6% range [2–9]. On the other hand, complications are more serious following surgical procedures and some of the patients need a reoperation, with further risks of postoperative morbidity.
To improve the long-term results of pneumothorax surgery and prevent recurrences, it is important to identify risk factors for reoperation. Some of these risk factors are well defined (underlying pulmonary disease) when others are not (type of surgery, age of the patient) [5,10–12]. We therefore studied the results of surgery for SP in our institution during an 8-year period.
2. Material and methods
2.1. Patient characteristics
This is a retrospective clinical study conducted on 240 consecutive patients that underwent 256 first-time operations for spontaneous pneumothorax in Lund University Hospital between 1 January 1996 and 31 December 2003. Patient information was gained from medical charts and operation reports.
The demographic distribution of the patients is shown in Table 1. There were 171 males and 69 females (M/F ratio 2.5:1). More than fifty percent of the patients (n=129) were either former or current smokers whereas 27.9% (n=67) had a confirmed COPD or emphysema (secondary SP).
2.2. Surgical technique
The surgery was performed by four senior surgeons. All procedures were performed with general anaesthesia and selective double lumen intubation. For VATS the patient was placed in a 90° lateral position and single-lung ventilation started before deflation of the lung with CO2 through a Veress-needle. Then a 10 mm trocar for the camera was placed in the sixth intercostal space in the mid-axillary line and a 5 mm trocar under the fourth rib, just below the scapula tip, for graspers and diathermy. The lung was carefully inspected. If blebs or bullae were found they were removed with a linear stapler (ETS-Flex 45, Ethicon Endo-Surgery Inc.) introduced through a 12 mm hole in the anterior fourth intercostal space.
In most cases the procedure was combined with pleurodesis and/or pleurectomy (see results), the mode of treatment being decided by the individual surgeon. Two kinds of pleurodesis were performed; the parietal pleura was either rubbed with a pledget of sandpaper or wide-mesh polypropylene gauze to achieve inflammation (mechanical pleurodesis), or chemical pleuritis was induced with talc powder (dry asbestos free talcum). Partial pleurectomy was performed apically from the fifth intercostal space both anteriorly and posteriorly. At the end of the procedure one chest tube was placed and connected to an underwater seal suction with a negative pressure of 20 cm H2O.
The thoracotomies were performed through an anterolateral incision through the 4th or 5th intercostal space with the patient in a 45° lateral position. Wedge resection, pleurectomy or pleurodesis was then performed in a similar fashion as described for the thoracoscopic procedure.
2.3. Postoperative care
Patients were extubated in the operating room and observed for 4–6 h in a postoperative care unit. Daily chest X-rays were obtained for each patient. Chest tubes were usually removed after 2–3 days postoperatively. At that time the lungs were fully expanded, no air leakage was present and pleural drainage was less than 100 ml per 24 h. Active physiotherapy was started on the first postoperative day and patients usually got patient-controlled analgesia or epidural analgesia if the procedure was performed through a thoracotomy. A control chest X-ray was done before discharge and 2–3 weeks postoperatively. A further follow-up was not conducted except in special circumstances where the patients had excessive postoperative pain or residual air.
2.4. Follow-up
On follow-up only recurrent pneumothorax requiring redo surgery was registered. Median follow-up was 54 months (range 9–99 months), with end of follow-up on 31 March 2004. Prolonged air leakage was defined as chest tube air drainage for more than 7 days postoperatively. Most of these patients were reoperated on within 10 days from the primary operation, after conservative treatment had failed.
2.5. Statistics
Patient information and intra- and postoperative data were collected on all patients. Continuous variables were checked using Student's t-test and categorial variables with Chi-square test. Logistic regression analysis was used to identify significant prognostic factors for reoperation, where odds ratio (OR) was used as a measure of risk of reoperation. Univariate analysis was performed for different clinical factors, including age and gender. Each factor that was statistically significant by univariate analysis adjusted by age was included in the multivariate logistic regression model. Statistical significance was set at P<0.05 and 95% confidence intervals were used for odds ratios.
3. Results
Altogether 256 operations were performed on 240 patients for spontaneous pneumothorax during the 8 years of the study. The indications for surgery are shown in Table 2. Most of the patients (58.6%) were operated on after experiencing one or more recurrences of pneumothorax. The remaining patients were operated on during their first episode of pneumothorax, usually due to persistent air leak or failure of re-expansion of the lung.
VATS was the most common type of surgery (93.0%) (Table 3). Six of the VATS cases (2.3%) had to be converted to a thoracotomy, most often due to inadequate exposure or extensive pleuropulmonary adhesions. Eighteen patients (7.0%) were primarily operated on with anterolateral thoracotomy, all of them being elderly with advanced COPD.
Wedge resection of blebs or bullae was performed in 226 (88.3%) of the cases (Table 3). In the remaining patients (11.7%) no bullae were found and only pleurodesis and/or pleurectomy were performed. Altogether pleurodesis was performed in 191 cases (74.6%) and apical pleurectomy in 100 cases (39.1%). A combination of wedge resection and pleurodesis was done in 162 cases (63.3%) and wedge resection, pleurodesis and pleurectomy in 43 cases (16.8%). Talc (35.1%) or sandpaper (28.9%) were the most common mode of pleurodesis.
The mean operative time was 63 min and the median length of stay was 4 days (range 1–54 days). Operative mortality (<30 days) was 0.8%, involving two patients operated with thoractomy. Both patients had advanced COPD and died of postoperative respiratory failure. There were no operative deaths after VATS (operative mortality 0%). Chest tubes could be withdrawn in 3 days (median). However, 29 patients (11.3%) had prolonged air leak that resulted in 13 early (<1 month) reoperations (5.1%), where missed blebs and staple leaks were found in 6 and 2 patients, respectively. Other early postoperative complications are summarized in Table 4. Postoperative, bleeding resulted in six reoperations (2.3%), the most common bleeding site being from the thoracic wall. Other complications were rare and most often minor, except for empyema that was found in two patients (0.8%), one of whom underwent evacuation and decortication.
A total of 15 patients (5.8%) were reoperated because of recurrent pneumothorax, on average 17 months (range 1–39 months) after the primary operation. Table 5 illustrates patient demographics, time of recurrence and the type of primary operations for the patients that were reoperated. No missed blebs were found. The late recurrences were treated with wedge resection in 5 patients (33.3%) and in 8 (53.3%) with talc pleurodesis. One patient was operated on with a middle lobectomy and another patient underwent pulmonary decortication. Seven of the redo operations were thoracotomies. Patients in the reoperation group were younger (25.5 vs. 42.9 years, P<0.01) and less often operated on with pulmonary wedge resection, compared to patients that were not reoperated (73.3% vs. 89.9%, P<0.05).
Risk factors for reoperation were evaluated with linear regression. Young patients (OR of advanced age per year 0.95, CI-95% 0.92–0.98, P=0.001) and patients operated on for recurrent (OR 5.2, CI-95% 1.39–19.51, P=0.015) or secondary pneumothorax with emphysema (OR 3.62, CI-95% 1.01–12.98, P=0.048) had an increased risk of having redo surgery. The risk for reoperation was also increased for patients that were not operated on with a wedge resection during the primary surgical procedure (OR of wedge resection 0.23, CI-95% 0.07–0.74, P=0.014). Genders, weight, length, BMI, laterality, pleurectomy and pleurodesis, including type of pleurodesis, were not significant predictive factors of recurrence. Risk factors were comparable for patients reoperated on for prolonged air leakage (early failure) or recurrent pneumothorax (late failure).
4. Discussion
This study shows that a significant number of patients operated on for spontaneous pneumothorax require a reoperation because of early or late failure (10.9%). The late reoperation rate of 5.8% is in line with most recent reports, where it usually lies in the 3–6% range [3,5,8,10,13–18]. However, our 5.1% early reoperation rate is higher than that reported elsewere [3,5,8,10,17,18] and is of concern. In most instances it could be explained by technical failure, i.e. air leak from staple lines or missed blebs/bullae.
There are no obvious explanations for this high reoperation rate. Our patient material includes both elective and emergency cases, except that pneumothorax secondary to trauma (e.g. vehicle accidents) were excluded. Some of the previously mentioned studies only include patients with primary SP, and not patients with secondary SP (27.9% in the present study), where risks for recurrent pneumothorax and other complications are increased due to underlying lung disease [5,10–12].
Our surgical technique is similar to that described by others and the same is true for postoperative care, including indications for chest tube removal [3,5,8–10,12,17,18]. All cases were performed by a team of four attending surgeons with many years of experience with operations for pneumothorax and specifically VATS. Furthermore, during this period residents or fellows did not perform pneumothorax surgery in our institution and the learning curve is therefore not a likely explanation for our results being different from others.
The reoperation rate is affected by the surgeon's indications for taking the patients back to the operating room. This is especially true for the patients with early failures. There were no formal criteria for a reoperation, however, patients with a significant and continuing air leakage for a week (or more) after surgery were usually reoperated, regardless of age. Surgery was often preferred over conservative measures, such as the application of talc slurry or tetracycline through the chest tubes, which is often painful for the patient and ineffective [19,20].
Risk factors for reoperations were similar for patients with early or late failure. This was especially true for patients not operated on with a pulmonary wedge resection. Most of these patients did not have visible blebs at the time of surgery, neither at the apex nor other parts of the lung. Therefore, only pleurodesis and/or limited pleurectomy was performed. Bullae are most often located at the apex of the lungs but can be difficult to identify during thoracoscopic surgery. Horio et al. found that patients operated on with VATS had higher recurrences compared to patients operated on with thoracotomy. They suggested that these differences could be explained by overlooked bullae in the VATS-group [21]. Compared to open surgery, air leakage tests are more technically challenging and difficult to interpret during VATS, and in the present series they were only performed selectively. Our results indicate that it is not adequate to only performing pleurectomy or pleurodesis in cases where blebs or bullae are not found. Other authors have also recommended wedge resection of the apex in all cases [11,18], pointing out that the protective value of wedge resection does not only lie in the removal of blebs, but also in the creation of inflammation that leads to adhesions between the lungs and the thoracic wall.
Younger patients had an increased risk of reoperation compared to older individuals. The reason for this is not known, and to our knowledge this has not been reported in other studies. Treatment strategies were similar for this subgroup of patients, except that talc pleurodesis was less seldom used in patients under 40 years of age.
Today VATS has replaced open pneumothorax surgery in most centres. VATS is considered to be a cost-effective procedure compared to conventional open surgery. It is also safe as demonstrated in the present study with zero mortality after 238 VATS procedures. Two patients died from respiratory failure after open surgery. This does not mean that open surgery is more dangerous than VATS, as the patients that underwent open surgery were older and had more often severe pulmonary disease. As for open surgery, complications after VATS are most often minor, and except for prolonged air leakage, postoperative bleedings are the most common early complications (2.3%). Only a handful of patients sustained serious complications, including two patients that had empyema. According to a number of studies, four of them randomised, postoperative pain and hospital stay after VATS is significantly reduced compared to open surgery while recurrence rates are only slightly higher [3,5,8,10,12–17,22]. However, other studies have reported much higher (up to 6–8 times) recurrence rates for VATS than for open surgery [19,23]. This is of concern and must be regarded as a shortcoming of the VATS approach. In general the rate of reoperation should be kept as low as possible as they are more technically challenging with a greater risk for thoracotomy and, therefore, added morbidity to the patient. The recurrence rates after VATS might also have to be taken into consideration, when the operation is performed on patients where recurrences must be avoided by all means, such as when the operation is performed on pilots and divers. Perhaps these patients should instead be offered conventional thoracotomy that only carries a 0.5–2% recurrence risk [24,25].
How can reoperations be prevented Data from previous studies are often difficult to interpret, most of the studies being non-randomised with a limited number of patients. Furthermore, the differences in procedures and treatment strategies make direct comparison difficult. Our surgical approach must be regarded as relatively radical regarding the parietal pleura. Wedge resection and pleurectomy were performed on 35.9% of the patients, 63.3% underwent pleurodesis and 16.8% of the patients had both pleurectomy and pleurodesis in addition to the wedge resection. However, neither pleurectomy and/or pleurodesis (nor type of pleurodesis) in addition to wedge resection, affected the rate of recurrent pneumothorax in the logistic regression model. Our data, therefore, do not support this treatment strategy, at least not in all cases. This is important since the risk for postoperative complications can theoretically be increased by adding a potentially traumatic procedure, like pleurectomy, to the parietal pleura. Wheras previous studies have shown a slight advantage of pleurectomy over pleurodesis [25], no such difference could be detected in the present series.
A shortcoming of this study is the fact that it is not randomised. A certain selection bias regarding different treatment strategies and surgeons is therefore possible. Still, we do not think that the non-randomised design of the present study significantly affects our results and/or conclusions. Cases were referred unselectively to each of the four operating surgeons, who thereafter decided treatment on an individual basis. Importantly, all of the four surgeons used a similar surgical technique and no differences in recurrence rates were found between the four surgeons (P<0.1).
To detect minor differences in treatment, e.g. differences between different types of pleurodesis, a larger number of patients would have been of value. However, 240 patients must be regarded as a significant number of patients, and we think that if there are differences between treatments, these differences are most likely small. A prospective randomised multi-centre study is the only way to address these questions properly.
5. Conclusions
Videothoracoscopic operations for pneumothorax are safe procedures and can be used for patients with both primary and secondary SP. However, there is a considerable risk of reoperations with more than one in ten patients needing further surgery due to recurrent pneumothorax or prolonged air leakage. This risk is increased in younger patients and patients operated on for secondary pneumothorax. Furthermore, pulmonary wedge resection seems to protect against recurrence, while pleurodesis and/or pleurectomy in addition to wedge resection, do not.
Acknowledgements
Helgi Sigvaldason PhD for statistical help, professor Jonas Magnusson MD, PhD for comments and Birgitta Sjgren for secretarial help.
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Abstract
Objectives: To identify risk factors for reoperation following surgery for spontaneous pneumothorax. Material and methods: This is a retrospective clinical study conducted on 240 consecutive patients operated on for spontaneous pneumothorax in Lund University Hospital between January 1996 and December 2003. Patient information was gained from medical charts and operation reports. Logistic regression analysis was used to evaluate risk factors. Median follow-up was 54 months. Results: Video-assisted thoracoscopic surgery (VATS) was used in 93% of the patients, where bullectomy with or without pleurodesis/pleurectomy was performed in most cases. Conversion to anterolateral thoracotomy was required in 6 cases (2.3%). Operative mortality (<30 days) was 0.8% (0% after VATS). Altogether 35 patients (13.7%) required a reoperation. Twenty patients were reoperated on within one month from surgery, most often due to prolonged air leakage (n=13, 5.1%) and bleeding (n=6, 2.3%). Fifteen patients (5.8%) were reoperated on because of recurrent pneumothorax, on average 17 months (range 1–39 months) after the primary operation. Significant independent risk factors for reoperation were; young age, operations performed for secondary pneumothorax due to emphysema and recurrent pneumothorax. The risk was also increased in patients where wedge resection was not performed. However, the type of pleurodesis or pleurectomy was not related to increased risk. Conclusions: A considerable number of patients require reoperation after VATS for pneumothorax. Most reoperations are due to prolonged air leakage or recurrent pneumothorax. The risk for reoperation is increased in younger patients, patients operated for recurrent or secondary pneumothorax, and in cases where pulmonary wedge resection is not performed.
Key Words: Pneumothorax; Recurrent pneumothorax; Surgical technique; Reoperations; Risk factors
1. Introduction
Spontaneous pneumothorax (SP) is a relatively common condition affecting mostly young and otherwise healthy individuals. It is most often caused by a rupture of apical subpleural blebs (primary SP) but can also occur in patients with underlying lung diseases, typically COPD or emphysema (secondary SP). Conservative management with needle aspiration or more commonly chest tube drainage remains the standard treatment for the first episode of SP. However, recurrences are frequent and in a long-term perspective 40% or more of the patients treated conservatively eventually require a more definite treatment [1]. This includes instillation of pleural irritants (e.g. talc, tetracyclin) or more frequently surgery, including excision of leaking blebs and pleurodesis. Until a decade ago operations for pneumothorax were performed through thoracotomy. Today most of these operations are performed with a minimal invasive technique using video-assisted thoracoscopic surgery (VATS). In contrast to conservative treatment, recurrence rates following surgery are low, most often in the 1–6% range [2–9]. On the other hand, complications are more serious following surgical procedures and some of the patients need a reoperation, with further risks of postoperative morbidity.
To improve the long-term results of pneumothorax surgery and prevent recurrences, it is important to identify risk factors for reoperation. Some of these risk factors are well defined (underlying pulmonary disease) when others are not (type of surgery, age of the patient) [5,10–12]. We therefore studied the results of surgery for SP in our institution during an 8-year period.
2. Material and methods
2.1. Patient characteristics
This is a retrospective clinical study conducted on 240 consecutive patients that underwent 256 first-time operations for spontaneous pneumothorax in Lund University Hospital between 1 January 1996 and 31 December 2003. Patient information was gained from medical charts and operation reports.
The demographic distribution of the patients is shown in Table 1. There were 171 males and 69 females (M/F ratio 2.5:1). More than fifty percent of the patients (n=129) were either former or current smokers whereas 27.9% (n=67) had a confirmed COPD or emphysema (secondary SP).
2.2. Surgical technique
The surgery was performed by four senior surgeons. All procedures were performed with general anaesthesia and selective double lumen intubation. For VATS the patient was placed in a 90° lateral position and single-lung ventilation started before deflation of the lung with CO2 through a Veress-needle. Then a 10 mm trocar for the camera was placed in the sixth intercostal space in the mid-axillary line and a 5 mm trocar under the fourth rib, just below the scapula tip, for graspers and diathermy. The lung was carefully inspected. If blebs or bullae were found they were removed with a linear stapler (ETS-Flex 45, Ethicon Endo-Surgery Inc.) introduced through a 12 mm hole in the anterior fourth intercostal space.
In most cases the procedure was combined with pleurodesis and/or pleurectomy (see results), the mode of treatment being decided by the individual surgeon. Two kinds of pleurodesis were performed; the parietal pleura was either rubbed with a pledget of sandpaper or wide-mesh polypropylene gauze to achieve inflammation (mechanical pleurodesis), or chemical pleuritis was induced with talc powder (dry asbestos free talcum). Partial pleurectomy was performed apically from the fifth intercostal space both anteriorly and posteriorly. At the end of the procedure one chest tube was placed and connected to an underwater seal suction with a negative pressure of 20 cm H2O.
The thoracotomies were performed through an anterolateral incision through the 4th or 5th intercostal space with the patient in a 45° lateral position. Wedge resection, pleurectomy or pleurodesis was then performed in a similar fashion as described for the thoracoscopic procedure.
2.3. Postoperative care
Patients were extubated in the operating room and observed for 4–6 h in a postoperative care unit. Daily chest X-rays were obtained for each patient. Chest tubes were usually removed after 2–3 days postoperatively. At that time the lungs were fully expanded, no air leakage was present and pleural drainage was less than 100 ml per 24 h. Active physiotherapy was started on the first postoperative day and patients usually got patient-controlled analgesia or epidural analgesia if the procedure was performed through a thoracotomy. A control chest X-ray was done before discharge and 2–3 weeks postoperatively. A further follow-up was not conducted except in special circumstances where the patients had excessive postoperative pain or residual air.
2.4. Follow-up
On follow-up only recurrent pneumothorax requiring redo surgery was registered. Median follow-up was 54 months (range 9–99 months), with end of follow-up on 31 March 2004. Prolonged air leakage was defined as chest tube air drainage for more than 7 days postoperatively. Most of these patients were reoperated on within 10 days from the primary operation, after conservative treatment had failed.
2.5. Statistics
Patient information and intra- and postoperative data were collected on all patients. Continuous variables were checked using Student's t-test and categorial variables with Chi-square test. Logistic regression analysis was used to identify significant prognostic factors for reoperation, where odds ratio (OR) was used as a measure of risk of reoperation. Univariate analysis was performed for different clinical factors, including age and gender. Each factor that was statistically significant by univariate analysis adjusted by age was included in the multivariate logistic regression model. Statistical significance was set at P<0.05 and 95% confidence intervals were used for odds ratios.
3. Results
Altogether 256 operations were performed on 240 patients for spontaneous pneumothorax during the 8 years of the study. The indications for surgery are shown in Table 2. Most of the patients (58.6%) were operated on after experiencing one or more recurrences of pneumothorax. The remaining patients were operated on during their first episode of pneumothorax, usually due to persistent air leak or failure of re-expansion of the lung.
VATS was the most common type of surgery (93.0%) (Table 3). Six of the VATS cases (2.3%) had to be converted to a thoracotomy, most often due to inadequate exposure or extensive pleuropulmonary adhesions. Eighteen patients (7.0%) were primarily operated on with anterolateral thoracotomy, all of them being elderly with advanced COPD.
Wedge resection of blebs or bullae was performed in 226 (88.3%) of the cases (Table 3). In the remaining patients (11.7%) no bullae were found and only pleurodesis and/or pleurectomy were performed. Altogether pleurodesis was performed in 191 cases (74.6%) and apical pleurectomy in 100 cases (39.1%). A combination of wedge resection and pleurodesis was done in 162 cases (63.3%) and wedge resection, pleurodesis and pleurectomy in 43 cases (16.8%). Talc (35.1%) or sandpaper (28.9%) were the most common mode of pleurodesis.
The mean operative time was 63 min and the median length of stay was 4 days (range 1–54 days). Operative mortality (<30 days) was 0.8%, involving two patients operated with thoractomy. Both patients had advanced COPD and died of postoperative respiratory failure. There were no operative deaths after VATS (operative mortality 0%). Chest tubes could be withdrawn in 3 days (median). However, 29 patients (11.3%) had prolonged air leak that resulted in 13 early (<1 month) reoperations (5.1%), where missed blebs and staple leaks were found in 6 and 2 patients, respectively. Other early postoperative complications are summarized in Table 4. Postoperative, bleeding resulted in six reoperations (2.3%), the most common bleeding site being from the thoracic wall. Other complications were rare and most often minor, except for empyema that was found in two patients (0.8%), one of whom underwent evacuation and decortication.
A total of 15 patients (5.8%) were reoperated because of recurrent pneumothorax, on average 17 months (range 1–39 months) after the primary operation. Table 5 illustrates patient demographics, time of recurrence and the type of primary operations for the patients that were reoperated. No missed blebs were found. The late recurrences were treated with wedge resection in 5 patients (33.3%) and in 8 (53.3%) with talc pleurodesis. One patient was operated on with a middle lobectomy and another patient underwent pulmonary decortication. Seven of the redo operations were thoracotomies. Patients in the reoperation group were younger (25.5 vs. 42.9 years, P<0.01) and less often operated on with pulmonary wedge resection, compared to patients that were not reoperated (73.3% vs. 89.9%, P<0.05).
Risk factors for reoperation were evaluated with linear regression. Young patients (OR of advanced age per year 0.95, CI-95% 0.92–0.98, P=0.001) and patients operated on for recurrent (OR 5.2, CI-95% 1.39–19.51, P=0.015) or secondary pneumothorax with emphysema (OR 3.62, CI-95% 1.01–12.98, P=0.048) had an increased risk of having redo surgery. The risk for reoperation was also increased for patients that were not operated on with a wedge resection during the primary surgical procedure (OR of wedge resection 0.23, CI-95% 0.07–0.74, P=0.014). Genders, weight, length, BMI, laterality, pleurectomy and pleurodesis, including type of pleurodesis, were not significant predictive factors of recurrence. Risk factors were comparable for patients reoperated on for prolonged air leakage (early failure) or recurrent pneumothorax (late failure).
4. Discussion
This study shows that a significant number of patients operated on for spontaneous pneumothorax require a reoperation because of early or late failure (10.9%). The late reoperation rate of 5.8% is in line with most recent reports, where it usually lies in the 3–6% range [3,5,8,10,13–18]. However, our 5.1% early reoperation rate is higher than that reported elsewere [3,5,8,10,17,18] and is of concern. In most instances it could be explained by technical failure, i.e. air leak from staple lines or missed blebs/bullae.
There are no obvious explanations for this high reoperation rate. Our patient material includes both elective and emergency cases, except that pneumothorax secondary to trauma (e.g. vehicle accidents) were excluded. Some of the previously mentioned studies only include patients with primary SP, and not patients with secondary SP (27.9% in the present study), where risks for recurrent pneumothorax and other complications are increased due to underlying lung disease [5,10–12].
Our surgical technique is similar to that described by others and the same is true for postoperative care, including indications for chest tube removal [3,5,8–10,12,17,18]. All cases were performed by a team of four attending surgeons with many years of experience with operations for pneumothorax and specifically VATS. Furthermore, during this period residents or fellows did not perform pneumothorax surgery in our institution and the learning curve is therefore not a likely explanation for our results being different from others.
The reoperation rate is affected by the surgeon's indications for taking the patients back to the operating room. This is especially true for the patients with early failures. There were no formal criteria for a reoperation, however, patients with a significant and continuing air leakage for a week (or more) after surgery were usually reoperated, regardless of age. Surgery was often preferred over conservative measures, such as the application of talc slurry or tetracycline through the chest tubes, which is often painful for the patient and ineffective [19,20].
Risk factors for reoperations were similar for patients with early or late failure. This was especially true for patients not operated on with a pulmonary wedge resection. Most of these patients did not have visible blebs at the time of surgery, neither at the apex nor other parts of the lung. Therefore, only pleurodesis and/or limited pleurectomy was performed. Bullae are most often located at the apex of the lungs but can be difficult to identify during thoracoscopic surgery. Horio et al. found that patients operated on with VATS had higher recurrences compared to patients operated on with thoracotomy. They suggested that these differences could be explained by overlooked bullae in the VATS-group [21]. Compared to open surgery, air leakage tests are more technically challenging and difficult to interpret during VATS, and in the present series they were only performed selectively. Our results indicate that it is not adequate to only performing pleurectomy or pleurodesis in cases where blebs or bullae are not found. Other authors have also recommended wedge resection of the apex in all cases [11,18], pointing out that the protective value of wedge resection does not only lie in the removal of blebs, but also in the creation of inflammation that leads to adhesions between the lungs and the thoracic wall.
Younger patients had an increased risk of reoperation compared to older individuals. The reason for this is not known, and to our knowledge this has not been reported in other studies. Treatment strategies were similar for this subgroup of patients, except that talc pleurodesis was less seldom used in patients under 40 years of age.
Today VATS has replaced open pneumothorax surgery in most centres. VATS is considered to be a cost-effective procedure compared to conventional open surgery. It is also safe as demonstrated in the present study with zero mortality after 238 VATS procedures. Two patients died from respiratory failure after open surgery. This does not mean that open surgery is more dangerous than VATS, as the patients that underwent open surgery were older and had more often severe pulmonary disease. As for open surgery, complications after VATS are most often minor, and except for prolonged air leakage, postoperative bleedings are the most common early complications (2.3%). Only a handful of patients sustained serious complications, including two patients that had empyema. According to a number of studies, four of them randomised, postoperative pain and hospital stay after VATS is significantly reduced compared to open surgery while recurrence rates are only slightly higher [3,5,8,10,12–17,22]. However, other studies have reported much higher (up to 6–8 times) recurrence rates for VATS than for open surgery [19,23]. This is of concern and must be regarded as a shortcoming of the VATS approach. In general the rate of reoperation should be kept as low as possible as they are more technically challenging with a greater risk for thoracotomy and, therefore, added morbidity to the patient. The recurrence rates after VATS might also have to be taken into consideration, when the operation is performed on patients where recurrences must be avoided by all means, such as when the operation is performed on pilots and divers. Perhaps these patients should instead be offered conventional thoracotomy that only carries a 0.5–2% recurrence risk [24,25].
How can reoperations be prevented Data from previous studies are often difficult to interpret, most of the studies being non-randomised with a limited number of patients. Furthermore, the differences in procedures and treatment strategies make direct comparison difficult. Our surgical approach must be regarded as relatively radical regarding the parietal pleura. Wedge resection and pleurectomy were performed on 35.9% of the patients, 63.3% underwent pleurodesis and 16.8% of the patients had both pleurectomy and pleurodesis in addition to the wedge resection. However, neither pleurectomy and/or pleurodesis (nor type of pleurodesis) in addition to wedge resection, affected the rate of recurrent pneumothorax in the logistic regression model. Our data, therefore, do not support this treatment strategy, at least not in all cases. This is important since the risk for postoperative complications can theoretically be increased by adding a potentially traumatic procedure, like pleurectomy, to the parietal pleura. Wheras previous studies have shown a slight advantage of pleurectomy over pleurodesis [25], no such difference could be detected in the present series.
A shortcoming of this study is the fact that it is not randomised. A certain selection bias regarding different treatment strategies and surgeons is therefore possible. Still, we do not think that the non-randomised design of the present study significantly affects our results and/or conclusions. Cases were referred unselectively to each of the four operating surgeons, who thereafter decided treatment on an individual basis. Importantly, all of the four surgeons used a similar surgical technique and no differences in recurrence rates were found between the four surgeons (P<0.1).
To detect minor differences in treatment, e.g. differences between different types of pleurodesis, a larger number of patients would have been of value. However, 240 patients must be regarded as a significant number of patients, and we think that if there are differences between treatments, these differences are most likely small. A prospective randomised multi-centre study is the only way to address these questions properly.
5. Conclusions
Videothoracoscopic operations for pneumothorax are safe procedures and can be used for patients with both primary and secondary SP. However, there is a considerable risk of reoperations with more than one in ten patients needing further surgery due to recurrent pneumothorax or prolonged air leakage. This risk is increased in younger patients and patients operated on for secondary pneumothorax. Furthermore, pulmonary wedge resection seems to protect against recurrence, while pleurodesis and/or pleurectomy in addition to wedge resection, do not.
Acknowledgements
Helgi Sigvaldason PhD for statistical help, professor Jonas Magnusson MD, PhD for comments and Birgitta Sjgren for secretarial help.
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