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MMCTS
(August 10, 2006). doi:10.1510/mmcts.2005.001453 Copyright © 2006 European Association for Cardio-thoracic Surgery Procedure Posterolateral thoracotomyHôpitaux Universitaires de Strasbourg, Département de Chirurgie Thoracique, Hôpital Civil, 1 Place de l'Hôpital, 67000 Strasbourg, France * Corresponding author: * Tel.: +33-38-811 6202; fax: +33-38-811 6077. E-mail: gilbert.massard{at}chru-strasbourg.fr
Lateral thoracotomies include many different variants with a common final pathway, consisting of an intercostal incision. They are the most frequent incisions in daily thoracic procedures. We will describe first the standard posterolateral thoracotomy, which has been the classic reference and then the muscle-sparing posterolateral thoracotomy. Surgical techniques, indications, pitfalls and tips are described. Discussion and an overview of the literature are developed.
Key Words: Muscle-sparing technique • Posterolateral thoracotomy
Indication Posterolateral thoracotomy is the historic gold standard of thoracic incisions, promoting an excellent exposure for most general thoracic procedures. However, it requires transection of large muscles with all inherent disadvantages; muscle-sparing variants should, therefore, be considered. This approach is also used for spinal operations [1].
Position
Local traditions explain the large variety of techniques to secure the patient's position: use of sandbags, rolled sheets front and back or bean bags supporting the back and the abdomen (Photo 2).
Legs are separated by a pillow or a padding. The lower leg is flexed at the knee and hip while the upper leg lies straight on the top of the pillow (Photo 3).
The lower arm either can be placed on an arm board at a right angle to the table or can be flexed at the elbow and placed beside the head (Photo 4).
The upper arm may be rotated forward and allowed to hang over the operating table supported by adequate padding. This serves to rotate the scapula forward. Straps secure the position.
It is helpful to outline the proposed incision with a felt-tipped marking pen. The inferior angle of the scapula, its spinal and axillary borders are palpated and outlined. The position of the vertebral spines and the nipple is notified. The standard incision follows the course of the underlying ribs, and extends from a point located at 3 inches from the mid-spinal line to the anterior axillary line, thus passing below the tip of the scapula. In an adequate positioning, the tip of the scapula should face the 6th rib (Video 1). The incision is deepened through the subcutaneous tissue and superficial fascia until the fasciae overlying the latissimus dorsi and trapezius muscle are exposed (Video 2). A total transection of the latissimus dorsi is performed using the electrocautery unit. The division of the trapezius muscle must be avoided. If extensive exposure is required, it will be divided in its anterior portion only (Videos 3 and 4). The anterior serratus and the rhomboid muscles are exposed; the inferior border of the rhomboideus and the posterior border of the serratus are facing a fatty triangle. The latter is separated from the muscles to get access to the ribcage. It may be helpful to insert a stay suture at the tip of this triangle, to serve as a landmark during closure. When this dissection is properly performed, the serratus can be elevated and retracted anteriorly, thus avoiding its transection.
Selection of the appropriate intercostal space can be guided by counting the ribs. The surgeon's hand is slipped below the scapula and gently pushed upwards to the apex. Palpation of the first rib is always possible, provided the hand is advanced along the posterior wing of the ribs; more laterally, the insertions of the scalenus posticus onto the second rib impede palpation of the first rib. Typically, the first rib is more or less circumscribed by the second, and a clear step can be palpated (Video 5).
The desired intercostal space is located and the pleural space is entered after dividing of the intercostal muscles with the electrocautery. As mentioned above, the intercostal muscle incision is made carefully, staying close to the lower rib of the interspace to avoid injury to the neurovascular bundle. The incision is pushed as far as possible anteriorly to allow for easy retraction of the ribs (Video 6). A large rib spreader is inserted, placing the larger blade in front of the scapula. The rib spreader is always opened slowly and progressively, to minimize the risk of rib fracture. Incision of the posterior part of the intercostal muscles, below the spinal muscles, may be completed from inside to completely free the ribs. Some authors advocate posterior transection of the rib to avoid fracture (Video 7). Closure of the incision starts by inserting pericostal sutures. We use several heavy absorbable sutures (polyglactine No 2 – MMCTSLink 99) which are placed 2 cm from each other. Each of the two musculofascial layers is closed with an absorbable running suture. The circulating nurse is asked to push the patient's shoulder back towards the incision to release tension during closure. Closure of the subcutaneous tissues and skin remains at the surgeon's preference.
The standard posterolateral thoracotomy requires a complete transection of the entire latissimus dorsi. However, muscle-sparing variants have been described since the latissimus can be a helpful muscle flap in an immediate or delayed timing. Complete sparing is possible by a careful and generous subcutaneous dissection. The posterior border of the muscle is then freed from the underlying rhomboideus in the upper part of the incision, and from the fatty triangle below. Anterior retraction is facilitated by transection of the thoracolumbar fascia giving the posterior insertion to the muscle. However, the exposure is still limited when compared to a lateral muscle-sparing thoracotomy. Further, the fatty triangle is most often severed and adequate repair of the underlying layer is impaired. Partial sparing is the more reasonable option. It refers to muscular anatomy. In the classification of Mathes and Nahai, the latissimus dorsi is a mixed-type of muscle: the anterior part has a well-identified pedicle origination from the thoracodorsal artery, while the posterior part is vascularized by several segmental pedicles. Further, the anterior part is usually much thicker. Hence it makes sense to preserve the most functional, i.e. anterior part. This variant requires development of a skin flap on the lower verge of the skin incision only. The posterior part of the latissimus is then severed from back to front, until the posterior border of the serratus is reached. This point is located in the vicinity of the tip of the scapula. After an insertion of a stay suture, the incision of the latissimus is curved downwards by separating the anterior part from the posterior between the fibers of the muscle. The anterior muscle flap may then be easily lifted from the underlying serratus. The fatty triangle is now exposed, and the incision is completed as above (Videos 8,9,10,11,12,13) [2,3,4,5].
During the division of the rhomboid major and minor muscles, care should be taken to cut at least 3 to 4 cm medial to the vertebral border of the scapula to avoid the deep branch of the transverse cervical artery and the dorsal scapular nerve. It is not necessary to divide the thoracolumbar fascia or paravertebral muscles which can be elevated by blunt dissection and retracted to expose the underlying rib posteriorly. During the count of ribs, confusion may arise regarding which rib is palpated in the apex: the first or second? As stated above, if the surgeon's hand follows the posterior, paraspinal wing of the ribs, the first rib can always be reached. During incision of the intercostal space, the surgeon should be concerned about possible adhesions. The pleura should be opened bluntly to check if the surface of the lung is free. When the surgeon inserts the rib spreader, he should take care not to block a portion of pulmonary parenchyma between the rib and the spreader. Rib fracture is frequent with this incision. The rib spreader must be progressively opened, slowly. As mentioned, transection of the rib at the costovertebral angle may improve retraction. It is recommended to excise subperiostally a small portion of the lower rib, to override the cut edges during the postoperative period. Economic longitudinal posterolateral thoracotomies have been reported. This approach allows for a smaller skin incision without preparing of skin flaps [6,7]. In the case of diffuse adhesions, there are two variants. Either the adhesions are loose or consist of fibrous bands, which can be freed in the intrapleural space by alternation of blunt dissection or cautery; or there are dense and firm adhesions, which immediately require development of the extrapleural plane. In the case of a redo thoracotomy, we prefer to use the same intercostal space. We always extend the skin incision anteriorly, and start opening the intercostal space in the most anterior area. There are two reasons: first, the intercostal space is larger, and the softness of the cartilages allows for easier retraction; second, the adhesions are softer in the anterior part of the pleural cavity. As soon as there is sufficient space, a small Tuffier retractor (MMCTSLink 102) is inserted. The dissection is carried preferably in the intrapleural space. The intercostal space is progressively opened from front to back and the surrounding lung is gently freed. The retractor is opened progressively, to avoid tearing of the lung. A larger Finochietto retractor (MMCTSLink 109) is inserted when adequate space has been developed. Sequellae of posterolateral thoracotomy have been reported in pediatric surgery [8]: deformity of the chest (18%), asymmetry of the nipples (63%), scoliosis ranging from 25 to 31%; winged scapula (77%), 14% of asymmetry of the chest wall due to an atrophy of the serratus anterior muscle, dysfunction of the shoulder (61%). More than 94% of this population presented with musculoskeletal deformities after posterolateral thoracotomies. Cherup reported that 60% of children subsequently complained with underdevelopment of the breast or pectoralis muscle [9]. Other authors have stressed the risk of scoliosis [10]. A special mention must be kept in mind about the use of oxidized cellulose to achieve hemostasis in posterolateral thoracotomies: several cases of paraplegia by compression of the spinal canal have been reported [11]. A limited access to the contralateral pleural space is possible; this may seem anecdotal but may avoid the need for a subsequent contralateral thoracotomy during surgery for metastases. The contralateral upper lobe may be approached by anterior mediastinal dissection, in the retrosternal space: the mediastinal pleura is severed, the thymic pad is swept of the sternum and reflected towards the pericardium. This exposes the contralateral mediastinal pleura, which is now ready for incision. It is of paramount importance to stay anteriorly to the thymus to avoid injury to the contralateral phrenic nerve. The contralateral basal segments can be reached in the retropericardial space. After division of the pulmonary ligament, the groove between esophagus and pericardium is exposed, and the overlying mediastinal pleura is entered. The esophagus is dissected off the pericardium, giving access to the contralateral mediastinal pleura. Incision in this area will be anterior to the contralateral pulmonary ligament. Exposure is maintained by reflecting the esophagus with a malleable retractor. At this point, the pulmonary ligament can be hooked with the finger or a dissector and be safely divided with bipolar scissors. Now, the lower lobe is freed and can be gently pulled up through the mediastinum. Two particular mentions must be underlined about the muscle-sparing technique. The first is that the key of the success of this procedure is an extensive but controlled division of the subcutaneous tissue to allow a good mobilization of the latissimus dorsi muscle. The second is that because of this extensive dissection, Redon drains must be placed at the closure to avoid a postoperative seroma.
This approach is classically credited to offer optimal exposure of all important structures. It has been the standard incision for pulmonary procedures for the past 90 years. This incision allows penetration of the thorax at any level between the third to the tenth rib. However, disadvantages of this approach include the division of major muscles of the chest, resulting in increased potential for blood loss and moderate time requirement for opening and closing the incision, prolonged ipsilateral shoulder and arm dysfunctions, compromised pulmonary function and chronic post thoracotomy pain syndromes. About 40% of the patients had troublesome chronic chest pain up to several years after undergoing a posterolateral thoracotomy and more than 60% of them required analgesia for pain one month after surgery. Postoperative scolioses have been described in children [12]. With advances in thoracic anesthesia, particularly unilateral endobronchial ventilation, the trend in thoracic surgery has been reduced to the size of incisions and to develop muscle-sparing thoracotomies. With adequate deflation of the underlying lung, most thoracic procedures can be performed safely through a limited incision. Many satisfactory muscle-sparing incisions have been described [13,14,15,16]. Its principal disadvantages would be to limit significantly the exposure and the surgical field, requiring longer real surgery time to dissect the mediastinum and to perform lymphadenectomy. Therefore, many authors preferred not to use this approach when chest wall resection or difficult hilar dissection is anticipated [17,18]. In addition, the time required to create the muscle-sparing incision was significantly longer than needed for the standard approach: the subcutaneous flaps must be mobilized from the latissimus dorsi and anterior serratus muscles. For these reasons, some authors advocate to use this one only for minor resections (segmentectomies, wedge resections) or ‘simple’ lobectomies [17,18].
"To be well exposed, it's the half of the success of a surgical procedure"
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Summary
Introduction
