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Computer-Mediated Power Stapling for Anatomical Lung Resection: Experience in 100 Consecutive Cases

Vigneswaran, Wickii T.*; Gruner, Charles†

Innovations: Technology & Techniques in Cardiothoracic & Vascular Surgery: Winter 2006 - Volume 1 - Issue 6 - pp 328-331
doi: 10.1097/01.IMI.0000229891.91345.6e
How-To-Do-It Article

Objectives: Mechanical stapling is widely used for lung resection. Complications related to the stapling are few but not infrequent. This varies from complete disruption of the staples to incomplete sealing of vascular structures. A stapling platform that has a strong clamping force with precise and consistent staple formation suitable for thickness of tissue is likely to be an advance in existing devices and may reduce the complication rate. A new, computer-mediated power stapling is currently available for lung resections, with three types of digital loading units (DLU). Clinical data on its use are limited. We report our experience with this stapling platform (SurgASSIST) in our first 100 patients undergoing anatomic lung resection.

Methods: Fifty-four men and forty-six women (mean age, 64 ± 7 years) underwent anatomic lung resections, using a lateral, muscle-sparing mini-thoracotomy, during 2004 to 2005, with the SurgASSIST platform. Three types of DLUs were used for lung resection: a linear cutter, a right-angled vascular cutter, and a right-angled bronchial cutter. Observational data were collected prospectively on the operative procedure, type of staples used, duration of operation, chest tube drainage, and hospital length of stay.

Results: There were 83 lobectomies, 5 bilobectomies, 5 segmental resections, and 7 pneumonectomies. A total of 502 DLUs (mean, 5 per patient; 102 vascular, 91 bronchial, and 309 linear cutters) were used in this series. There were no major operative complications. The mean operating time was 136 ± 41 minutes. One bronchial dehiscence and one incomplete sealing of the pulmonary vein in the staple line were observed. In one patient, the linear cutter could not be opened in the automatic setting. There were 15% misreads by the computer on the DLU or their inserts. There was one hospital death unrelated to the stapling. Twenty additional complications included prolonged chest tube drainage (n = 8), reoperations (n = 2), atrial fibrillation (n = 5), hemothorax (n = 1), chylothorax (n = 1), C-dif colitis (n = 1), myocardial ischemia (n = 1), and incarcerated ventral hernia (n = 1). The median hospital length of stay was 5 days (range, 3 to 26 days) and the median length of chest tube drainage was 3 days (1 to 22 days).

Conclusions: Our experience shows that the computer-mediated power stapling of lung parenchyma and hilar structures during anatomic resection is safe and reproducible.

From the *Department of Surgery, University of Chicago, Chicago, Illinois; and the †Department of Surgery, Loyola University Medical Center, Maywood, Illinois.

Presented at the annual meeting of the International Society for Minimally Invasive Cardiothoracic Surgery, San Francisco, CA, June 2006.

Address correspondence and reprint requests to Wickii T. Vigneswaran, MD, FACS, University of Chicago, 5841 South Maryland Avenue, MC 5040, Chicago, IL 60637. E-mail:

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The advantage of preserving large chest wall muscle during thoracotomy has motivated surgeons and patients to pursue a minimally invasive approach for major lung resection.1–4 It becomes necessary to use stapling devices to facilitate the lung resections, particularly to complete fissures and control the vascular and bronchial structures in the hilum during minimal access lung resections. Despite wide use of these staples, it is not unusual to encounter partial or complete disruption of the staple line, resulting in air leaks, bleeding, and bronchial stump dehiscence.5–8 In addition, the lack of right-angled articulation limits optimal application of the currently available devices on vascular or bronchial structures. A new computer-mediated power stapling platform (SurgASSIST, Power Medical Interventions, Langhorne, PA) has become available for lung resection.9–11 In this stapling platform, a computer-controlled console transfers the mechanical forces through a maneuverable flexible shaft that attaches to a detachable stapling digital loading unit (DLU). It has three types of DLUs, one of which can be applied straight and the other two at a right angle, for vascular and bronchial structures. There are only a few case reports of the use of this platform during major lung resections.11 We review our use of the SurgASSIST platform in lung resection during muscle-sparing mini-thoracotomy and report our observational experience with the first 100 anatomic lung resections.

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Between February 2004 and December 2005, 152 major pulmonary resections were performed in 148 patients, using the SurgASSIST stapling device. Approval from the Loyola University Medical Center Institutional Review Board for Protection of Human Subjects was obtained for reviewing patient charts and the thoracic surgery database. This report is based on the first 100 patients undergoing anatomic lung resection, using the SurgASSIST stapling platform. Patients who had undergone wedge excisions or video-assisted thoracoscopic procedures with the use of the SurgASSIST platform are not included in this report. Prospective data were collected on all patients for the number and type of DLU used, complications associated with the stapling, type of surgical procedure, operating time, length of chest tube drainage, and hospital length of stay. Operative and postoperative complications were recorded. A prolonged chest tube drainage was defined as chest tube requirement beyond 7 days after the operation.

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SurgASSIST Platform

The SurgASSIST is composed of a console that houses a microprocessor, a remote control unit, a flexible shaft with option for rigid extender, and a DLU (Fig. 1). The DLU houses the staple cartridge with a knife blade. The remote control unit assists in accurate placement and closure of the DLU and firing of the staple and the knife mechanism.

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Operative Technique

A 7- to 9-cm lateral incision was performed below the scapula in the line of standard lateral thoracotomy, preserving latissimus dorsi and the serratus anterior muscles (Fig. 2). Tissues between the lobes were divided by using the power linear cutter (SLC, Fig. 3) to complete the fissure. The SLC was also used to wedge out nodules of unknown origin for frozen-section diagnosis before anatomic resection. Smaller pulmonary arterial branches were ligated and divided. The vascular right-angled linear cutter (RALCV – Fig. 4) was used to divide the pulmonary veins and large pulmonary artery branches. A right-angled linear cutter (RALC) was used to divide the bronchus. After systematic mediastinal lymph node dissection, the chest was closed, leaving a single chest tube.

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The data were prospectively collected and entered onto data sheets. The results are reported as median and range or mean and standard deviation.

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One hundred consecutive anatomic lung resections were performed between February 2004 and December 2005, using the SurgASSIST computer-assisted stapling platform in 54 men and 46 women with a mean age of 64 ± 7 years (range, 26 to 84 years). Of these 100 resections, 83 patients underwent a single lobectomy, 5 bilobectomies, 7 pneumonectomies, and 5 segmentectomies; 55 patients underwent a right-sided and 45 a left-sided lateral muscle-sparing mini-thoracotomy. In this group, there were 9 complex resections (Table 1). These were 2 sleeve resections, 6 en bloc chest wall resections, and 1 extrapleural completion pneumonectomy. Five hundred two SurgASSIST staple cartridges were used to perform the 100 anatomic lung resections; 309 of them were SLC, 102 were RALCV (vascular), and 91 were RALC (bronchial). The bronchus was stapled by using an RALC 30 for lobectomy (lobar bronchus) and an RALC 45 for pneumonectomy (main bronchus). The mean operating time was 136 ± 41 minutes. Intraoperative or immediate postoperative complications encountered with the SurgASSIST stapling device were very few. There was one incomplete firing of the vascular staple on a vein and one bronchial dehiscence that presented in the early postoperative period, both in patients who had undergone neoadjuvant chemoradiation. There was one instance in which the SLC would not open after firing in the automatic mode. These complications occurred during the early part of the experience and none since. There were a few (15%) computer misreads of the cartridge placement or the insert placement, more of a nuisance than a safety issue. There was one hospital death (1% mortality) as a result of sepsis secondary to aspiration pneumonia. There were 20 additional postoperative complications; prolonged chest tube in eight, reoperations in two, one for a bronchial stump dehiscence (described above) and the other for a pleural space problem, postoperative atrial fibrillation in five, hemothorax in one, chylothorax in one, C-dif colitis in one, myocardial ischemia in one, and incarcerated ventral hernia in one. The median hospital length of stay was 5 days for all patients (range, 3 to 26 days), and the median duration before chest tube removal was 3 days (range, 1 to 22 days, Table 2).

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Anatomic resection remains the standard of care for early-stage lung cancer and certain types of benign conditions. Minimally invasive approaches are increasingly applied for lung resections because of the advantages of preserving the chest wall muscles. Staples are widely used for division of lung parenchyma, hilar vessels, and bronchus and have been shown as safe or safer than suturing.5,12 In addition, mechanical stapling helps to reduce the overall cost of care for the patient by reducing operating time and hospital length of stay.7,13 The use of instrumentation for video-assisted surgical procedures, particularly the endo-stapling instruments, has facilitated wider adaptation of minimally invasive approaches.7,14,15 The technology of endo-stapling had been available now for more than 3 decades, but only small measurable advances have been made in the hand-actuated staple devices. The shortcomings have largely remained mostly unchanged. The main issues have been disruption of staples leading to staple line bleeding or dehiscence of tissue with resultant leak of fluid or air. The primary concerns have been malalignment of staples, nonuniform and excessive tissue clamping, and improper staple closure. A “smart” stapling device that can ensure proper alignment of staples, control of the clamping force, and appropriate staple formation for the required thickness of the tissue would be an advantage over the existing staple devices. The SurgASSIST platform computer microprocessor has been designed to communicate with the DLU for the staple alignment, strong and consistent clamping force of the tissues, and precise staple formation suitable for the thickness of the tissue. However, studies must be done to compare and confirm these features. The computer-mediated stapling reduces the torque and tension that can occur with hand-actuated devices, but it is unclear if this feature reduces the poststapling complication rate. Our initial observational data are encouraging.

The flexshaft was thought be an advantage for placing the staple cartridges, in view of the fact that it is flexible. We found the flexibility more of a hindrance for precise placement of the cartridge. The power extender in the SurgASSIST platform is an optional feature. In our opinion, the power extender gives the necessary stability to the cartridge and assists in the precise placement of the DLU. The first-generation right-angled stapling cartridges are bulky and cannot be used in video-assisted thoracoscopic approach. However, the RALC and RALCV provide stapling at right angles and division of tissues with a preinstalled knife, a feature not available with other angled stapling instruments. The remote control allows the assistant to operate the controls, including firing the instrument, freeing the surgeon’s hands. This provides the opportunity to the surgeon to manipulate or position structures away from the stapling area. We found this to be an advantage in the mini-thoracotomy approach for lung resection.

Like any new technology, there is a learning period. The operator needs to become comfortable with the SurgASSIST stapling platform. Once this period has elapsed, the technology is very surgeon-friendly and easily adoptable. Despite the minor shortcomings, the first-generation SurgASSIST stapling platform is safe, and the results are reproducible.

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Lung; Thoracotomy; Lung cancer surgery; Minimally invasive surgery; Surgical instruments

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