Rib osteotomy and fixation: Enabling technique for better minithoracotomy exposure in cardiac and thoracic procedures

Abstract

Chronic postthoracotomy pain is a common complication of thoracotomy, occurring in approximately 50% of patients.1Rogers M. Duffy J.P. Surgical aspects of chronic post-thoracotomy pain.Eur J Cardiothorac Surg. 2000; 18: 711-716Crossref PubMed Scopus (199) Google Scholar Severe and disabling pain affects 5% of patients after thoracotomy. Chronic postthoracotomy pain persists for greater than 2 months after the surgical procedure and is characterized by allodynic responses to mechanical and cold stimulation. To date, there is no objective evidence that postthoracotomy pain diminishes over time, despite popular opinion.2Buvanendran A. Kroin J.S. Kerns J.M. Nagalla S.N. Tuman K.J. Characterization of a new animal model for evaluation of persistent postthoracotomy pain.Anesth Analg. 2004; 99: 1453-1460Crossref PubMed Scopus (86) Google Scholar Chronic postthoracotomy pain is thought to result from intercostal nerve damage sustained during rib retraction or reduction.2Buvanendran A. Kroin J.S. Kerns J.M. Nagalla S.N. Tuman K.J. Characterization of a new animal model for evaluation of persistent postthoracotomy pain.Anesth Analg. 2004; 99: 1453-1460Crossref PubMed Scopus (86) Google Scholar A variety of surgical modifications have been developed to overcome this painful complication, ranging from local rib resection to muscle-sparing thoracotomies and mobilization of the intercostal nerve. Here we describe a thoracotomy technique that minimizes intraoperative trauma to the intercostal neurovascular bundle, preserves chest wall integrity, and permits adequate exposure of the surgical field. The patient is draped and positioned for a standard thoracotomy. Before incision, the ribs and intercostal spaces are carefully marked. The surface of the rib superior to the desired level of the incision is identified and an incision through the epidermis is made along the inferior margin of this rib. Electrocautery is used to clean the entire anterior surface of the superior rib over a length of 6 to 10 cm. Access to the neurovascular bundle is then achieved by dissection through external and internal intercostal muscle. At the posterior extent of the thoracotomy, the neurovascular bundle is locally dissected off the rib over about 3 cm. If present at the thoracotomy site, the innermost intercostal muscle is dissected free from the rib. An oblique osteotomy is made using a ring cutter, care being taken to avoid the mobilized neurovascular bundle (Figure 1, A). A soft tissue retractor is then used to reduce the direct contact with the neurovascular bundle. The rib retractor is then placed within the confines of the soft tissue retractor, minimizing direct contact with the rib bone superiorly and inferiorly while keeping the neurovascular bundle out of the way (Figure 1, B). When the surgical procedure is complete and the chest needs to be closed, the rib fragments are reduced and apposed in anatomic alignment. A modified SternaLock straight titanium plate (Biomet Microfixation Inc, Jacksonville, Fla) is secured in place with screws on either side of the osteotomy (Figure 1, C). We used this plate with 10-mm self-tapping screws to secure the plate early in our experience. Over the past 18 months, we have changed to using modified mid-face plates (Biomet Microfixation), using a thin 4-holed plate that is fixed with 7-mm self-tapping screws. Pericostal sutures are often not required to realign the intercostal spaces. The muscles, superficial fascia, and skin are closed in the standard fashion. Figure 2 is an operative photograph of the rib with the oblique osteotomy and Figure 3 shows the rib aligned and plated at the end.Figure 3The rib is aligned and plated at the end.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The standard thoracotomy incision is made along the superior border of the rib to avoid trauma to the neurovascular bundle during the incision. This approach leaves the neurovascular bundle vulnerable to intraoperative trauma from compression and tension during rib retraction. The resulting nerve damage subsequently causes chronic postthoractomy pain. The procedure we describe herein enables the surgeon to place the neurovascular bundle out of harm's way during intraoperative rib retraction. In addition, the osteotomy of the rib provides better access and visualization through a small incision. This is true for both cardiac and thoracic surgical procedures. These factors reduce the intraoperative nerve trauma and the resultant chronic postthoracotomy pain. We have used this technique in anterolateral thoracotomies for cardiac procedures in over 140 patients and 10 thoracic procedures between January 2005 and April 2009. None of these patients has had long-standing postthoracotomy pain. There have been no instances of delayed wound healing. The most remarkable finding is that these patients are able to cough early in the postoperative period without the dramatic and severe pain seen in most standard thoracotomies. As a result, physical therapy and mobilization in the postoperative period are much easier.