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Ann Thorac Surg 2003;76:2071-2074
© 2003 The Society of Thoracic Surgeons
a Division of Cardiothoracic Surgery, Veterans Affairs Puget Sound Healthcare System, Seattle, Washington, Spiration, Inc., USA
Accepted for publication May 14, 2003.
* Address reprint requests to Dr Vallières, Division of Cardiothoracic Surgery, Box 356310, University of Washington, Seattle, WA 98195, USA
e-mail: evallier{at}u.washington.edu
Abstract
PURPOSE: This study assessed the feasibility of using the VALR surgical system (Spiration Inc, Redmond, WA), limited by federal law to investigational use, for capturing and reducing a selected portion of affected lobes in patients undergoing lobectomy.
DESCRIPTION: The tested system consists of a hand-held vacuum-regulated introducer loaded with a flexible, silicone sleeve. Targeted tissue is drawn into the introducer and the silicone sleeve is deployed and sutured in place. The end of the proximal sleeve includes a compression band for applying uniform radial pressure, suture ports, and silicone lugs lining the inner lumen for reinforcing sleeve position.
EVALUATION: The system was effective in capturing 25% to 30% tissue of each lobe tested. Mean intraoperative test time was 8.5 minutes. The compression sleeve did not slip or dislodge after suturing, and no tissue damage or leaks were observed.
CONCLUSIONS: It was feasible using vacuum to draw and isolate a portion of pulmonary tissue within a silicone sleeve. The system was intuitive to apply, easy to use, and produced effective reduction and sealing of tissue.
Thoracic surgical procedures for resecting or repairing diseased lung tissue are often complicated by air leaks, necessitating intraoperative repairs and frequently lead to prolonged hospitalization and increased patient morbidity [1, 2]. Evolving methods and materials for managing air leaks are reported to have decreased the incidence and duration of air leaks, which led to trends in earlier hospital discharge and reduced the frequency of reoperation, particularly in patients with emphysema [2–4]. Despite reported progress, air leaks remain a common postoperative complication and persist for more than 5 days in 15% to 48% of patients [2, 5, 6].
Researchers emphasize that reduction of air leaks lies in their prevention through careful surgical dissection and tissue closing techniques [2, 4]. As standard methods for sealing lung parenchyma, sutured and buttressed staple lines may compound trauma to lung tissue and yield inconsistent results [2, 7]. Furthermore, intraoperative air leaks can occur distant to the operative site and may be attributed to surgical manipulation or trauma and to pressure or tension referred to adjacent tissues [8].
Recently, a novel approach has been described for arresting air leaks and bleeding and for selectively capturing and reducing emphysematous tissue (VALR surgical system; Spiration, Inc., Redmond, WA). Preclinical studies report the ability to use controlled vacuum to easily capture lung tissue within a silicone sleeve. Once deployed, the device applies radial compression sufficient to occlude air and blood flow to the encapsulated tissue [9, 10]. This clinical study was designed to assess the feasibility of using the VALR surgical system to effectively capture lung tissue and to deploy silicone sleeves onto a targeted portion of lobes of patients undergoing anatomical lung resection. Observations were made regarding device fixation and attachment, ease of use, length of time required, and the presence of air leaks following deployment of the compression sleeve.
Description
The study protocol was approved November 21, 2001 by the Human Subjects and Review Committee (University of Washington, Seattle, WA) and the Research and Development Committee, Department of Veteran Affairs (Puget Sound Healthcare System, Seattle, WA). Adult patients scheduled to undergo lobectomy, or pneumonectomy were consecutively screened and enrolled into the study from March through May 2002. Informed consent was obtained from each of 9 patients entering the study. All patients enrolled were male, ranging in age from 55 to 79 years old with a preliminary diagnosis of resectable nonsmall cell carcinoma.
Eight patients advanced to surgery and were prepped according to established operating procedures. All were intubated using a standard double-lumen endotracheal tube. Diagnostic fiberoptic bronchoscopy and cervical mediastinoscopy were performed sequentially and in the usual manner. One patient was excluded at bronchoscopy from further study due to biopsies indicative of small cell carcinoma. Seven enrolled patients proceeded to posterolateral thoracotomy by a single surgeon for clinically indicated resection of nonsmall cell carcinoma. One patient was excluded at thoracotomy for central tumor involvement and whole lung atelectasis. In the remaining 6 patients, diseased lobes were dissected from adjacent tissues using conventional techniques. After ligation of the pulmonary vessels and prior to division of the involved bronchi, testing of the VALR system was conducted.
For each lobe application, a flexible, smooth, thin silicone sleeve (resting inner diameter 17.5 mm, nominal length 22.5 cm) was loaded onto a polycarbonate hand-held vacuum regulated introducer (expanded inner diameter 35mm; Fig 1). The opening of the loaded introducer was positioned against the targeted tissue, remote to the tumor and within the lobe otherwise planned for resection. Targeted tissue was gently drawn into the translucent introducer as a vacuum pressure, was manually adjusted to a maximum of 20 cm Hg. This allowed the surgeon to control the rate and volume of tissue positioned within the instrument (Fig 2). The silicone sleeve was then deployed from the introducer onto the captured tissue and sutured in place using two U-stitch sutures (straight blunt safety needle, polyester suture, size 0) laced perpendicular to one another through molded suture ports.
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The involved lobe was re-inflated and tested under warm 0.9% saline solution for air leaks (peak ventilator pressure 20 cm to 40 cm water). Observations were made regarding intraoperative use and local impact of the investigational device. Elapsed time for device loading, capture and deployment, suturing, and air leak testing were recorded.
The lung resection then proceeded in the routine manner. A pathologist conducted gross examination of the freshly resected lobes and sleeve-compressed tissue. The pathologist resected the distal portion of the sleeve and compressed tissue leaving only a short (2.5 cm) section of silicone material attached to the lobe. Lobes were then re-inflated and formalin tested for leaks and device stability. Tissue captured by the compression sleeve was then excised and examined.
Evaluation
Five of 6 patients underwent right posterolateral thoracotomy. The right upper lobe was targeted for clinical resection in each of 3 patients, the right lower lobe in 1 patient, and right upper and middle lobes in 1 patient. Moderate pleural adhesions were reported in 2 of 5 right-sided patients. Only 1 patient underwent left posterolateral thoracotomy for resection of the left lower lobe and extensive adhesions were noted in this patient. Intraoperative evidence of emphysema was observed in 4 of 6 patients—subjectively graded as minimal to mild in 3 patients, and moderate (visible bullae < 2-cm diameter) in 1 patient.
The VALR surgical system was effective in capturing an estimated 25% to 30% of lobar tissue in all patients. With every application, the surgeon was able to control and visualize the rate and volume of lung tissue filling the silicone sleeve and transparent introducer. The silicone sleeves were readily deployed onto the captured tissues without incident. There was no associated pulling or tearing of tissues adjacent to the sleeves during deployment and suture fixation. No migration or dislodgement of the compression sleeves was observed when tested intraoperatively under positive airway pressure inflation.
No air leaks were observed within the sleeve-captured tissue or in tissues adjacent to the proximal compression band. In 4 of 6 patients air leaks were detected outside the experimental field and were attributed to surgical dissection, unrelated to the system evaluation.
A cumulative mean time of 8.5 minutes (range 6–13 minutes) was recorded for performing the described test procedure in the 6 patients. Time required for device loading, sleeve deployment, suturing, and in vivo air leak testing for patients 4, 5, and 6 used a mean time of 7.0 minutes, or 30% less than the mean time of 10 minutes in the first 3 patients. One silicone sleeve was torn during loading and was attributed to operator error, and a second sleeve was immediately reloaded.
Pathology examination revealed atraumatic radial compression in all patients. The compression sleeve was positioned appropriately distal to the hilum to avoid cartilaginous airways. Bronchioles measuring 1 to 3 mm diameter were captured within the sleeve. Appendant tissue within the cylindrical sleeve implant measured 7 to 10 cm in length (reported only for specimens four through six). No device related abrasions or lacerations were observed in adjacent tissues. The pathologist resected the distal portion of the sleeve and reduced lung tissue. The proximal silicone sleeve containing the compression band, suture ports, and compression lugs remained securely attached. No air leaks or sleeve migration was observed when pressure formalin tested.
Comment
Over the past decade there have been great improvements in surgical instrumentation and techniques allowing safe and effective lung resections for a variety of conditions. The VALR surgical system evaluated in this study provided a very innovative tool and promising new technique for lung surgery. The described instrumentation has been carefully designed to capture delicate tissues using controlled vacuum. The hand-held system is intuitive, easy to use, and allows the operator full control of the targeted lung tissue. In this clinical protocol, the surgical system was tested after ligation of the pulmonary vessels to minimize interference with scheduled anatomical cancer resection. Based on preclinical studies of VALR sleeve deployments and tissue resection in non-devascularized lungs [9, 10] we believe the application of silicone compression sleeves in patients without ligation of the pulmonary vasculature will prove similarly favorable.
Further design modification may be justified to minimize demand on intraoperative time and to optimize system assembly. Although the size of compression sleeves tested in this patient series appeared to be appropriate for capturing targeted tissues with one application, further studies may be required to determine if a range of sizes is needed or if multiple sleeve deployments are needed in different conditions. Though the described suturing procedure was satisfactory, improved techniques may be necessary for surgical approaches other than posterolateral thoracotomy. In this study, repeated operator use of the VALR surgical system appeared to substantially reduce the procedural time required (mostly assembly), even over this series of just 6 patients.
Additional studies are warranted to identify patient variables that may influence application of this promising surgical technique and the effects of tissue compression over time. Future studies should be conducted to evaluate the system's potential role in improving upon current tools and techniques for excising lung tissue and for managing air leaks. Potential indicated uses for the VALR system in its present configuration may include: lung volume reduction, major bullectomy, blebectomy, and management of peripheral air leak in routine lung resection. Smaller caliber systems could lead to the application of this technique in video-assisted thoracoscopic surgery (VATS).
In conclusion, this clinical study in patients scheduled for anatomic resection of lung tissue demonstrated the feasibility to effectively capture and isolate pulmonary tissue using controlled vacuum, and to successfully deploy a single silicone compression sleeve onto large portions of targeted lobes. The VALR surgical system tested in this study was intuitive and easy to use producing no trauma or air leaks in the lung tissue where applied.
Footnotes
This study was supported by a grant from Spiration, Inc, Redmond, Washington. The authors have performed an independent assessment and were instrumental in developing study design, methods, data analysis, and writing of this report. Spiration Inc (Redmond, WA) sponsored this study providing VALR surgical systems for testing and reimbursement of expenses associated with conducting the study.
References
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