- Author: Rohit Shahani, MD, MS, MCh; Chief Editor: Zab Mosenifar, MD, FACP, FCCP more...
The evolution of the surgical incision has been closely correlated to the major developments in the field of surgery, medicine, and technology. In the early days, prior to the development of general anesthesia and positive pressure ventilation, the incisions were mostly small and were used predominantly to drain localized infectious complications, or they were ingeniously designed to be used via an extra pleural approach especially to lower thoracic structures.
With the use of general anesthesia, incisions got bolder and larger and the posterolateral thoracotomy was the most widely used approach. The ability to isolate the ipsilateral lung for surgery and the introduction of new stapling devices allowed the use of smaller more focused incisions with muscle-sparing techniques and minimal rib-spreading. Currently, videoscopic thoracic surgery has introduced a whole new array of minimally invasive options. Thus, we have come full circle back, using the same small incisions in the chest, but with the ability to do much more complex resections than what was done many decades ago.
The continued evolution of cardiac surgery has made the median sternotomy and its many variations one of the most widely used incisions in for cardiac surgery, which are occasionally used for thoracic surgery.
A thoracic incision can be seen in the image below.
The appropriate incision is the one that will provide the best exposure to the region of the thorax, and, to make that judgment, a thorough understanding of the anatomy of the thorax is an absolute prerequisite. For example, in most major lung resections it is the hilum of the lung that should be well exposed.
Emphasis is often placed on the muscle groups that need to be divided during the procedure. The latissimus dorsi and the serratus anterior are the main muscles of the lateral chest wall. The pectoralis muscle and the rectus abdominis require attention during anterior incisions. The most important muscles of the posterior chest wall include the trapezius, the rhomboids, and the paraspinous muscles (see image below). Special incisions that include partial sternotomies and first rib resections require a thorough knowledge of the anatomy of the base of the thoracic cage.
Principles of surgery
The goal of the surgery, like everything we do in medicine, is to optimize the likelihood of a successful outcome from the planned procedure.
The first principle is that the incision should provide adequate exposure, especially during the most technically challenging part of the operation. This is aided by a thorough understanding of the surface anatomy and a comprehensive review of the radiographic images that are obtained preoperatively.
The next principle is to preserve chest wall function and appearance as best as possible. These include nonspreading VATS procedures, muscle-sparing techniques, avoiding excessive rib retraction, and rib preservation when possible.
Strict layered closure is the rule in thoracic surgical incisions. Care should be taken in approximating the individual divided chest wall muscles in appropriate layers, otherwise a significant delay in their recovery or range of motion results. Being careful never to overapproximate the ribs and prevent an override is important because this contributes significantly to postoperative pain.
Similarly, divided bony tissue, especially the sternum as in a median sternotomy, should be rigidly approximated. Excess rib or sternal motion decrease the efficiency of chest wall movements and increase the work of breathing, especially in the setting of postoperative pain.
Historically, 2 chest tubes are used to drain the thoracic cavity postoperatively. The anterior tube is directed apically, expected to drain air leaking (A-tube), while the posterior (back) tube is placed basally expected to drain fluids (blood; B-tube). However, with the tendency toward minimally invasive approaches, often one chest tube is used. Tubes less than 20 French in size tend to kink and are not recommended. Tubes are usually removed when the drainage is less than 400 mL/24 hrs and no air leaks and their function is no longer required.
Most thoracic operations are facilitated by the placement of a double-lumen endotracheal tube or a bronchial blocker by the anesthesiologist. This allows isolation of the ipsilateral lung and greatly facilitates the conduct of the operation. Isolating the lung during minimally invasive or videoscopic thoracic surgery is almost mandatory. Often, the patient's poor pulmonary reserve does not permit single lung ventilation and lung isolation.
Postoperative pain is best controlled with an epidural analgesic. This catheter is placed by the anesthesiologist usually prior to the induction of general anesthesia and is also used effectively intraoperatively to complement the general anesthesia. Pain control can also be achieved with an extrapleural, paravertebral catheter with a continuous infusion of fentanyl and/or bupivacaine (0.1%). In the event these options are unavailable, an intercostal nerve block with long-acting local anesthetic, such as 0.5% bupivacaine with epinephrine, at the time of chest closure aids with postoperative pain.
Preoperative, prophylactic antibiotics, usually within the hour preceding the skin incision, have been found to produce a significant reduction in wound infection rates and infectious complications. Usually a first-generation or a second-generation cephalosporin is chosen as the drug of choice, especially targeting Staphylococcus aureus, which is the most common pathogen.
During positioning the pressure points should be well padded. Foam pads for the elbows, an axillary roll for the dependent axilla to avoid injury to the brachial plexus, and pillows placed beneath pressure points on the legs are standard precautions that are taken.
An assessment of the risk of possible venous thromboembolism should be individualized for each patient. Measures to reduce this risk include tight elastic hose stockings, use of sequential compression devices, and perioperative use of heparin or Lovenox should be considered in all patients.
The median sternotomy is the incision of choice for most cardiac surgical operations. It offers excellent exposure to the heart, pericardium, great vessels, thymus, anterior mediastinal structures, lower trachea, and carina and is well suited for bilateral pulmonary procedures like resection of bilateral pulmonary metastasis. Left lower lobe pulmonary resection is quite challenging from this approach, and access to posterior mediastinal structures like the esophagus and the distal descending thoracic aorta is not possible. The advantages of this incision are that it is quick to perform, especially in hemodynamic emergencies, and it produces less pain than a traditional thoracotomy. The main drawback is cosmetic, and a risk of sternal malunion exists, which is usually associated with a postoperative infection.
The patient is placed supine with both arms padded and draped at the patient’s side. A vertical midline incision is made from below the sternal notch up to the tip of the xiphoid process. The pectoral fascia (and muscles if present) is divided and the periosteum is scored with a cautery. Palpating the lateral margins of the sternum facilitates identification of the midline. The sternum is divided in the midline with a power saw. Periosteal bleeding needs to be meticulously controlled, and, occasionally, the marrow bleeding requires bone wax or one of the newer commercially available water-soluble, absorbable agents to tamponade marrow oozing.
The retractor should be placed lower in the incision and should be spread slowly to avoid tearing of tissue with particular attention to the innominate vein. Minimal spreading minimizes traction on the upper ribs and reduces occult fractures and neurologic insult on the brachial plexus.
Simple sternal wire closure or a figure-of-8 wire closure is the common method of closing the sternum. No. 6 and No. 7 stainless steel wires are commonly used in adults. Mersilene ribbon and occasionally non-absorbable sutures are used, commonly in children. Robicsek et al described a lateral sternal wire weave that reinforces the lateral sternal edges for a more secure closure. At least 2 wires in the manubrium and 4 or more wires in the body of the sternum are required for a tight secure closure. Alternatively, newer techniques that use plates and screws can also be used to close the sternum.
If bleeding from an internal thoracic vessel occurs, it is controlled with a figure-of-8 stitch. It is also very important to ensure that the mediastinal drain is not entrapped in the wound closure. The pectoralis fascia is then closed so that the wires are not visible and the rest of the incision is closed in layers in the standard fashion.
Reoperative sternotomy and each additional reparative entry (second, third, fourth) carries an increased mortality over the initial sternotomy. This is directly related to the increased operative mortality during the performance of a repeat sternotomy. Exposing the femoral artery and vein prior to opening the sternum for urgent access to institute cardio-pulmonary bypass is prudent.
If excessive difficulty is anticipated during repeat sternotomy, based on the preoperative evaluation of the patient including their previous operative reports and preoperative chest radiograph (especially the lateral view), instituting femoral-femoral cardio-pulmonary bypass prior to the performance of the repeat sternotomy is safe.
The use of an oscillating saw facilitates sternal reopening. Appreciating the depth of penetration with the oscillating saw is the key to a successful sternal reopening. Elevating the previous sternal wires to provide upward retraction of the sternum is well described and is a useful technique to know.
Mediastinitis is the most serious complication following median sternotomy. The reported incidence is 0.6%–5% with an associated mortality of 0-36%. COPD, prolonged ICU stay, respiratory failure, connective tissue disease, male sex, morbid obesity, uncontrolled diabetes mellitus, and possibly the use of bilateral mammary arteries as conduits were all associated with a higher incidence of sternal wound complications. Principles of treatment include IV antibiotics, operative debridement and either delayed primary closure or closure after transposition of muscle flaps or omentum.
A common variation of the median sternotomy is the partial sternal split, and it provides adequate access to the anterior superior mediastinum. It is often combined with a transverse collar neck incision to provide wide cervico-mediastinal exposure. The sternotomy can be extended supra-clavicularly, usually on the right side for exposure of the innominate, subclavian and carotid vessels. The partial sternotomy is also an integral part of the trap-door incision, which includes a supraclavicular incision as well as a transverse anterior thoracotomy, most commonly on the right-side with excellent exposure of the superior mediastinum and the superior sulcus region and large anterior mediastinal masses.
The patient is positioned supine and the sternal saw is used to divide the manubrium. Depending upon the extent of exposure required the sternal split ends at the level of the manubrial-sternal junction or below it. Often, a J-type incision in the sternum is extended into the third or fourth interspace as a controlled cut (see the image below). Rarely, a T-junction is created at the end of the partial sternotomy. If excessive spreading is performed of the sternal edges, it results in a fracture of the lower end of the sternal incision.
The most popular incision that most thoracic surgeons are familiar with is the thoracotomy (see the image below).[5, 6] A standard posterolateral thoracotomy incisions transects the latissimus dorsi muscle. An anterolateral thoracotomy transects the serratus anterior muscle. No specific written definitions for each type of thoracotomy incision exist, but defining the standard thoracotomy incisions according to their relationship to the latissimus dorsi muscle, which is arbitrarily considered lateral, is probably useful. If incisions are completely anterior or posterior to the latissimus dorsi muscle, they are called anterior and posterior thoracotomies, respectively.
The advantage of a thoracotomy incision is that it is extremely versatile and flexible and gives excellent exposure to the entire ipsilateral hemithorax, including the lung, esophagus, mediastinum, and cardiac structures. The major disadvantages of the incisions are related to the division of main muscle groups with their attendant postoperative pain and detrimental effect on pulmonary function. Also, a significant potential exists for poor exposure if the wrong interspace is chosen to enter the thorax and if single-lung anesthesia is not possible.
Historically the posterolateral thoracotomy has been the standard thoracotomy incision for most procedures, but, recently, smaller incisions with decreased functional disability and postoperative pain are more frequently used.
The patient is placed in a full lateral decubitus position with appropriate pressure point padding. Soft rolls, bean bags, and straps of 2-inch adhesive tape are used to secure the patient to the table. The lower leg is flexed at the hip and at the knee, while the upper leg is straight with pillows in between the legs. The dependent arm is flexed as is the superior arm to assume the so called "praying position." Safely preventing the upper arm from overhanging onto the chest is important because this can limit the surgeon’s space to maneuver instruments within the bony thorax. Widely preparing and drape the patient and marking the incision and significant anatomic landmarks with a felt tip pen prior to skin incision is also important.
The skin incision is designed to allow upward retraction of the scapula. The incision starts in front of the anterior axillary line at the anterior border of the latissimus dorsi muscle and passes 3-6 cm below the scapula tip and extends posteriorly and cephalad midway between the posterior midline over the vertebral bodies and the medial border of the scapula. The latissimus dorsi is identified and divided in line with the incision using electrocautery with some muscular vessels requiring individual ligation.
The serratus anterior muscle is in a deeper plane, and it is divided as low down as possible close to the muscular attachment to minimize the amount of distal denervated muscle. In this same plane, posteriorly, a small portion of the trapezius muscle or higher up the rhomboid muscles may need to be divided if required for additional exposure.
The desired interspace to be entered is located by positioning the hand up along the paraspinal muscles and by lifting the scapula with a large broad retractor. Sometimes the first rib is difficult to palpate, but the attachment of the serratus posterior superior muscle to the second rib is almost always discernable. Also the second intercostal space is usually the widest intercostal space that is palpable and serves as an added guide to correctly counting the ribs.
More than one way of entering the pleural space exists. The intercostal approach is the commonest and easiest method to enter along the superior border of the rib to avoid injury to the underlying intercostal neurovascular bundle. Alternatively, an approach through the periosteal bed is also commonly used. The periosteum is raised off the superior border of the rib after scoring it with an electrocautery. The pleural cavity is then entered through the periosteal bed, preferably having the anesthesiologist hold ventilation at the time of entry into the pleural cavity.
Before extending the pleural incision, ensuring that the lung is not directly adherent to the chest wall is important. Many surgeons advocate a short-segment rib resection in elderly patients and those with brittle bones to decrease the incidence of rib fractures and improve exposure. This method of "shingling" involves excising a 1-2 cm segment of rib at the costo-vertebral angle posteriorly. For repeat thoracotomies, resecting a long segment of rib subperiosteally and entering the pleural space through the resected rib bed is often prudent, because extensive adhesions at the reoperation may exist, and this wider entry facilitates safe pleural entry.
A large Finochietto-type rib retractor is used to open the incision inserting the large blade superiorly to ensure that the scapula is retracted. Sometimes a smaller, Tuffier-type rib spreader can also be used anteriorly to widen the exposure. Opening the rib spreader slowly and gradually to avoid rib fractures is important.
At least 4 pericostal sutures using heavy absorbable material like No. 2 polyglycolic acid are placed. If a rib is resected, wider sutures are placed around the remaining ribs. Sometimes a rib reapproximator (Bailey type) or towel clips are required to support the ribs while the sutures are tied, taking care not to overapproximate the space. The muscular layers are approximated with running suture with the latissimus dorsi muscle ideally closed in 2 layers, separately reapproximating the anterior and posterior fascial layers and minimizing muscular bunching (see image below).
Anterior (anterolateral) thoracotomy
The anterior thoracotomy has seen a resurgence with the recent trends towards minimally invasive cardiac and thoracic surgical techniques. In the emergency setting, it allows rapid access to the left chest, pericardium and also the aorta. It is the incision of choice for open lung biopsy, especially in sick patients who would not be able to tolerate single-lung anesthesia.
The patient is positioned supine with the arm padded and tucked to the side or placed over the patient on an arm rest. The skin incision begins just lateral to the sternal edge and follows the inframammary crease up to the anterior axillary line. The angle of Louis and hence the second rib is used as a reference point to count the ribs. The dissection is carried down to the chest wall dividing the pectoralis major and minor, and the medial edge of the serratus anterior muscles. Entry into the higher intercostal space requires control of the anterior perforating arterial branches to the pectoralis muscles.
Extended medial exposure can be achieved by controlling and dividing the internal thoracic vessels and extending the incision trans-sternally. One or both costal cartilages may be divided with an angled rib cutter to gain wider exposure.
During closure it is difficult to achieve rib re-approximation anteriorly; therefore it is important to perform a multi-layered closure of the muscle and soft tissue to prevent local wound dehiscence.
The original axillary thoracotomy was developed for operations on the thoracic sympathetic nervous system. It is a useful incision for first rib resection, apical bullous lung disease, management of spontaneous pneumothorax with apical pleurectomy, and wedge resections, but now most of these procedures are routinely performed thoracoscopically. The main advantage of this incision is the minimal muscle transection, the ease of performing this incision, and a scar that is largely hidden under the arm. The main drawback of this incision is that the exposure is primarily limited to the upper half of the chest and the potential of nerve injury to the intercostobrachial nerve and the long thoracic nerve.
The patient is placed in the lateral decubitus position with the ipsilateral arm flexed at the elbow and rotated superiorly, where it is suspended vertically and secured to a strand so as to open up the axilla, taking care not to over extend the arm. A 6-cm curvilinear incision is made at the base of the axillary hairline from the anterior margin of the latissimus dorsi to the posterior margin of the pectoralis major muscle. These muscles are retracted, and the third intercostal space is identified.
Care is taken to preserve the long thoracic neurovascular bundle that courses in the posterior aspect of the incision over the ribs. If the incision is used for first rib resection, blunt dissection is carried upwards to develop the plane taking care of the intercosto- brachial nerve that exits the second intercostal space.
During closure, the retracted muscles are allowed to fall back in place after the pericostal sutures are placed. In certain situations, when no significant thoracic drainage is expected, no pleural drain is placed and the inevitable small pneumothorax post operatively is usually well tolerated.
Muscle sparing variants of standard thoracotomy incisions are now the standard thoracotomy incision that most thoracic surgeons use. The advantage of reduced postoperative pain, reduced narcotic usage, and improved shoulder girdle muscle strength have been well documented. Postoperative seroma formation and the potential for compromised exposure during surgery are the minor drawbacks of this approach. Also, varied terms are used to describe the muscle-sparing techniques (eg, limited lateral, muscle-sparing posterolateral, extensive lateral, the vertical axillary) among the types of thoracotomies that have been described. Most variations are in the specifics of the skin incision used and the extent of muscle sparing involved with or without the development of extensive flaps.
The modified muscle-sparing posterolateral thoracotomy raises extensive skin flaps over the latissimus dorsi and trapezius muscles, which are then separated, and the latissimus is detached posteriorly by an incision in the thoracolumbar fascia. The serratus anterior muscle is detached from its rib insertion inferiorly and retracted anteriorly along with the latissimus. Most commonly, however, the latissimus is divided as in a standard thoracotomy, and the serratus anterior muscle is preserved after mobilizing it and retracting it anteriorly.
A useful option is to make an incision from the tip of the scapula posteriorly and inferiorly extending it forward for about 10 cm as in a standard lateral thoracotomy. Flaps are raised and the anterior edge of the latissimus is incised vertically and the plane between the latissimus and the serratus anterior is developed. Similarly, the posterolateral edge of the serratus is incised and the muscle is elevated and the plane developed. The latissimus is retracted posteriorly, and the serratus retracted anteriorly to expose the intercostal space.
Often the ribs need to be counted from below upwards in this modified low thoracotomy and the highest interspace that can be entered is the fifth interspace because not enough space exists to insert a hand to count the ribs from above.
The vertical axillary thoracotomy described by Baeza and Foster and popularized by Ginsberg gives adequate muscle sparing exposure for middle and lower lobe lung resection, but access to the upper chest can be problematic.[7, 8] The incision begins high in the axilla along the anterior border of the latissimus dorsi muscle and extends vertically down the posterior axillary line. The latissimus is retracted posteriorly, and the serratus muscle is retracted anteriorly after the appropriate planes are developed. This approach is probably not recommended if difficult hilar dissection is anticipated.
In 1966, Chamberlain and McNeill introduced anterior parasternal mediastinoscopy to stage and diagnose advanced upper lobe lung cancers. Access to level 5 (aorto-pulmonary window) and level 6 (preaortic) lymph nodes on the left and to level 3 (prevascular), level 4 (lower right paratracheal), and level 10 (tracheobronchial) lymph nodes on the right, as well as biopsy of mediastinal masses, makes this approach a useful diagnostic procedure in the armamentarium of the thoracic surgeon.
The patient is positioned supine with a small shoulder roll, the bed is in reverse Trendelenburg position to reduce central venous pressure, and the parts are widely prepped and draped in case an extended thoracotomy or sternotomy is required in the event of catastrophic bleeding. A 6-cm transverse incision is positioned over the second or third costal cartilage parasternally.
The pectoralis muscle fibers are retracted after division, and the costal cartilage is excised from its bed. The mediastinal space is entered through the perichondrial bed and care is taken to control bleeding from the internal thoracic vessels. An alternate technique uses an intercostal incision preserving the costal cartilage and usually requires the pleura to be opened. In the original description, the pleura is swept laterally to access the mediastinal structures. Use of a lighted mediastinoscope and deep narrow retractors can greatly aid the exposure during the operation. Closure usually does not entail pleural drainage, and the incision is closed in multiple layers.
The limited exposure afforded by this incision, the inability to visualize the posterior hilar structures, and the frequent sacrifice of the internal thoracic vessels are significant disadvantages of this incision. The incision can be extended as an anterior thoracotomy if needed or the above can be done thoracoscopically.
The transverse thoracosternotomy is probably the most morbid of all the thoracic incisions described. It has seen a resurgence in carefully selected indications, including resection of large mediastinal masses, double lung transplantation, bilateral pulmonary metastasectomy, and as an extension of the emergency anterior thoracotomy performed by a trauma surgeon to resuscitate a patient in extremis. It provides excellent wide exposure to both lungs, the mediastinum, and great vessels but causes increased postoperative pain, frequently requires the patient to be on postoperative ventilatory support, and carries a serious risk of sternal malunion and chest wall dysfunction.
The patient is placed supine with both arms extended over the face with the elbows flexed and secured to a stand. Bilateral anterior thoracotomies are performed along the inframammary crease, coursing upwards in the midline to the appropriate fourth or fifth intercostal space, where the transverse sternal incision is to be performed (see the image below). After the pleurae are opened, the internal thoracic vessels are divided bilaterally, the sternum is divided transversely with a power saw, a Gigli saw, or a Lebsche sternal knife. Rib spreaders are usually placed on both sides, taking care not to open the chest too widely to prevent traction injury of the phrenic nerves.
Closure requires interrupted or figure-of-8 heavy gauge wire sutures to close the sternum, and the thoracotomies are closed in the standard layered fashion as previously described. Multiple parallel, vertical Kirschner wires in the reapproximated sternum reduce override and shift of the sternal ends.
The hemi-clamshell combines an anterior thoracotomy with a partial upper sternal split. It is a rarely used approach but gives excellent exposure to large central pulmonary lesions and other special situations, large invasive mediastinal tumors, and excellent access to the brachiocephalic vessels and the intrapericardial pulmonary vessels.
The patient is placed supine, and an anterior thoracotomy incision in the inframammary crease is first performed up to the sternal midline. Exploration to confirm resectability should always be completed prior to committing to the sternal incision. The skin incision is then extended vertically upwards to the sternal notch and then for a short distance along the ipsilateral sternocleidomastoid muscle in the neck. The fourth intercostal space is entered at the top of the fifth rib, and the internal thoracic vessels are controlled prior to sternal opening. The upper partial sternotomy is performed from above downwards in the midline of the sternum and curved out to the fourth interspace in a J-type cut.
While placing the retractor, care should be taken to avoid undue traction on the brachial plexus. Meticulous closure involves perfect sternal reapproximation with wires and the use of pericostal sutures for the intercostal space incision, all of which are closed in multiple layers.
The thoraco-abdominal incision provides wide exposure of the lower thorax, upper abdomen and the retroperitoneal space. It offers excellent exposure for thoraco-abdominal aneurysms and cancer of the gastro-esophageal junction and for pathology of the lower thoracic and upper lumbar spine. The left side is preferred because retraction and mobilization of the liver and inferior vena cava on the right are more problematic than the spleen or aorta on the left.
The patient is placed in the right lateral decubitus position with the hips rotated back at least 45 degrees to increase abdominal exposure.
Alternatively, the patient is placed supine with the left side elevated and rotated with a support extending from the hip to the chest on the ipsilateral side. If the supine position is used, the ipsilateral arm is padded and supported by the patient’s side, extended out 90 º or suspended across the chest. The skin incision is made from the anterior axillary line diagonally forward at the appropriate rib level to a point in the abdomen midway between the umbilicus and the xiphoid process. Depending on the structures to be approached, the incision can be extended both towards the tip of the scapula or downwards below the umbilicus. Also, the vertical abdominal portion of the incision can be placed in the midline or a paramedian abdominal incisional approach can be chosen.
The latissimus dorsi and serratus muscles are divided and the scapula is elevated. The chest wall opening is determined by the specific operative procedure, but, most commonly, the seventh intercostal space approach is used. A short segment of costal cartilage at the transition to the abdominal incision is often removed to facilitate later rib and costal reapproximation during closure. The abdomen is opened in layers with the electrocautery. The left hemi diaphragm can be opened radially to the esophageal hiatus or can be opened circumferentially leaving a 2-3 cm rim of diaphragm on the chest wall for later reapproximation. Care is taken to avoid injury to the main phrenic nerve and its large branches.
During closure, the diaphragm is closed with large, nonabsorbable sutures. The chest drains are routine, and a standard thoracotomy closure is achieved. The retroperitoneum is not usually drained. The costal margin is closed with 1 or 2 figure-of-8 heavy sutures that incorporate the upper edge of the diaphragm to prevent post-operative hernia formation.
Of special interest is the open thoracoabdominal approach for lower thoracic and upper lumbar spine pathology. Once again, a left-sided approach is preferred. The spinal levels to be exposed should be well marked and imaged with fluoroscopy prior to prepping and draping. Usually a posterolateral thoracotomy is required and the 10th or 11th rib is resected subperiosteally. The diaphragm is divided circumferentially, taking care to leave a rim on the chest wall for later re-approximation. The peritoneum is left intact and is swept forward from lateral to medial taking care not to injure the spleen. Special care is taken to avoid injury to the aorta at the diaphragmatic hiatus. The segmental intercostal vessels over the involved vertebral bodies are controlled, ligated, and divided.
Respiratory complications are worrisome after these thoracoabdominal approaches, and atelectasis of the left lower lobe of the lung is frequently reported.
Extrathoracic approach to the thorax
Special incisions that are sometimes used to expose intrathoracic structures without the need of a thoracotomy constitute the extrathoracic incisional approaches to the thorax. The 3 approaches that are discussed here include the transcervical (collar) approach, the subxiphoid approach, and the transdiaphragmatic approach. The main disadvantage worrisome to all these approaches is the limited intrathoracic exposure that they offer for the surgery.
The transcervical approach is a standard transverse suprasternal (collar) neck incision that can be used to access anterior superior mediastinal pathology like the thymus, mediastinal parathyroids, substernal goiters, and anterior mediastinal cysts and tumors. The substernal space is bluntly dissected, and special self retaining retractors, preferably with built-in lighting, are used to expose the anterior, superior mediastinum. This incision can be extended in a T-incision with a vertical midline skin incision and either a partial or complete sternotomy can be added to achieve wider mediastinal and cardiac exposure.
The subxiphoid approach is frequently used to drain a pericardial effusion. It is a vertical midline incision centered over the xiphoid process. The retro xiphoid space is developed and the xiphoid can either be excised or split in the midline up to its junction with the lower end of the sternum. The retrosternal space can then be developed and the sternum elevated to allow access to the pericardium. The incision can easily be extended into a sternotomy either partial or complete with a vertical midline superior extension.
When Thirlby et al described the transdiaphragmatic approach to the lower esophagus it was an alternative approach that provided excellent limited access via a laparotomy. It allows access to the posterior mediastinum upon the level of the T8 vertebra. It was originally described as a semi-circular incision in the central tendon of the diaphragm that gives excellent exposure to the lower esophagus. After mobilizing the left lobe of the liver up to the left hepatic vein and opening the greater or hepatic omentum, the crus of the diaphragm are identified.
More commonly, an incision is made into the right crus of the diaphragm. This can be extended anteriorly for increased exposure. In cases of unexpected extension of the pathology at surgery the laparotomy can be extended upwards into a sternotomy either partial or complete. Alternatively a separate thoracotomy can be added either left or right depending on the individual pathology.
Thoracic surgeons with a special interest in foregut procedures, specifically those involving the esophagus and proximal stomach, should be versatile and comfortable using laparoscopic techniques to perform operations like myotomy for esophageal mobility disorders and fundoplication for gastro-esophageal reflux disease, etc.
Port placement as in thoracoscopy is the key to a smooth laparoscopic procedure. A thorough knowledge of the abdominal wall musculature and the surface anatomy aids the thoracic surgeon in choosing the optimal location for the ports. The access port is usually located in the left upper quadrant of the abdomen about 2 inches from the umbilicus. The liver retractor port is placed in either the right subcostal or in the subxiphoid position, depending on the specific type of retractor that is used. Working ports are typically placed in the midline epigastrium and in the right subcostal region, especially if the surgeon stands between the patient’s legs for the operative procedure. Additional ports for retraction depend upon the procedure and the intra-abdominal findings at laparoscopy.
Unlike videothoracoscopy, laparoscopy requires the establishment of a pneumoperitoneum to prevent the abdominal wall from collapsing on the intra-abdominal contents during the conduct of the procedure. Carbon dioxide is insufflated to a maximum pressure of 15 mm of Hg. The flow rate on the CO 2 insufflation is also important to monitor as low flow rates, especially during the initial port placement indicate obstruction to the Veress needle, a problem that should be promptly addressed.
The technique for initial port placement is usually dependent on the surgeon’s preference and where the (intra-abdominal) adhesions are anticipated.
The safest and most common open technique is that of Hasson. The skin incision is deepened and the anterior fascia is grasped with clamps and incised. A heavy suture is passed on each side to elevate the abdominal wall and a hemostat is used to bluntly dissect the remaining layers of the abdominal wall down to the peritoneum. The surgeon usually passes a finger to sweep the inside of the peritoneal cavity to ensure a free peritoneal space and only then is the blunt tip trocar inserted and a pneumoperitoneum established.
For more routine procedures in which adhesions are unlikely to be encountered, a closed technique is used. The skin incision is made and the entire abdominal wall is lifted up and a Veress needle is passed bluntly into the abdomen, appreciating the three separate clicks of the anterior and posterior rectus fascia and then the transverse abdominis/peritoneum layer along the way. The pneumoperitoneum is established as previously described, maintaining the CO 2 flow and pressure.
Once the pneumoperitoneum is established, the spring-loaded retractable, trocar type port is quickly inserted with a twisting motion into the peritoneal cavity. Some surgeons use the clear plastic tipped retractors that allow a 0 º telescope to view the fascial layers as they are encountered while entering the peritoneum, and this appears to be a safe compromise alternative to the Hasson technique.
Closure of the laparoscopic port sites is usually straightforward, although various innovative fascial closure techniques exist to reduce the risk of hernias which is 1-5%, more common if large ports are used. Ports should be removed under vision to ensure hemostasis.
Video-assisted thoracic surgery
The technique of thoracoscopy was first described by Jacobeus, a Swedish physician, who used a cystoscope to examine the pleural space in 1910. In 1991, the application of video technology to thoracoscopy revolutionized the procedure as it allowed the entire operation team to see the operative field as in an open procedure. Improvements in optics, lighting systems, and endoscopic instruments, including staplers, has had a profound impact on the evolution of VATS techniques. Patient demand is now the main force that drives the thoracic surgeon to perform VATS procedures.
A rigid bony thorax and collapsible lungs provide an excellent closed space to use video surgery without requiring positive pressure insufflation. Benefits of thoracoscopy include less pain in the early post operation period, an enhanced ability to view some operative regions, better cosmetics, and improved shoulder girdle function. It has yet to be proved beneficial in the long term in regards to pulmonary function.
Most VATS procedures on the lungs, pleura, esophagus, and posterior or middle mediastinum the patient is placed in the lateral decubitus position, and it permits easy conversion to the thoracotomy, if necessary (see image below). Flexing the distal half of the table is important in permitting adequate range of motion for instruments within the rigid thoracic cavity. Few procedures, like bilateral procedures for metastasectomy, sympathectomy, bleb resection, and anterior mediastinal procedures like thymectomy require the patient to be in the supine position with the arms extended.
The procedures are performed under general anesthesia with single lung ventilation. In approximately 20% of patients undergoing VATS, intraoperative conversion to the thoracotomy is required for various reasons, including extensive adhesions, intraoperative complications, inability to locate small lesions, requirement of a more extensive procedure, etc. Instruments for an open thoracotomy should always be readily available, possibly opened and ready on the back table, should an emergency thoracotomy be required.
The basic strategy in VATS techniques is the triangulation concept with the camera and the operating ports at the base of the triangle and the area of interest at the apex of the triangle so that they are all oriented in the same direction, facing the target disease within a 180 º area. The camera port is usually located between the working port tiles. The smallest ports that will permit safe performance of an operation are selected.
For most procedures, the scope is inserted through a port placed between the mid-axillary line and the posterior axillary line at the seventh or eighth intercostal space, choosing to be more posterior on the left side because the heart prevents epidemic visualization from the more anterior location. The 2 additional working ports are placed in the fifth intercostal space in the anterior mid axillary line and the other one is placed at the fifth space, parallel to and about 2-3 cm away from the posterior border of the scapula. In some tall individuals with hyperinflated lungs and for apical lesions, the port sites are all moved superiorly by one or two intercostal spaces.
Accessory incisions are frequently required, especially when lesions need to be directly visualized or palpated, and when complex assisted procedures are performed to manipulate regions of interest and use standard instruments for dissection and vessel width.
The accessory or utility thoracotomy incision is positioned just posterior to the pectoralis muscle, usually in the mid-axillary line and is 4-8 cm in length. The delineation between a VATS procedure and a small thoracotomy is theoretically breached if rib spreading is required. For lower lobe lung lesions, the access incision is the fifth space, and the fourth space is used for upper or middle lobectomies, using the appropriate pulmonary vein as the guide. These basic concepts of port placement and incisions are modified as recently to accommodate the procedures being performed and the location of the lesion being removed.
A small 1-2 cm incision is made at the appropriate site, and a hemostat is used to dissect the subcutaneous tissue and intercostal muscles at the upper border of the rib. Electrocautery under vision or blunt dissection is used to dissect through the muscles and the pleura. Care should be taken to ascertain a free pleural space and only then should a port be inserted. If any doubt exists, the incision is enlarged to permit digital exploration of the pleural space and sweep away flimsy adhesions, enough to permit the placement of the videothoracoscope.
A few surgeons use initial carbon dioxide insufflation to hasten the lung collapse but it is important to monitor the cardiovascular status during this maneuver.
The entire thoracic cavity is explored systematically. Additional port sites are placed under direct vision using the telescope and camera. It is easier to insert larger ports through the anterior chest, where the intercostals spaces are wider.
At the conclusion of the operative procedure, one or more chest drains may be placed through the existing port sites. Port sites are removed under vision to ensure hemostasis and are closed in layers making sure to close the muscular-fascial layer separately.
Few issues are specific to the performance of a videothoracoscopic procedure. Intercostal neuralgia is usually caused by pressure on an adjacent intercostal nerve by a trocar. The incidence can be reduced by using smaller trocars and making an adequate incision. It is treated with nerve blocks and anti-inflammatory agents. Rarely, major vascular injuries occur, and, should this happen, the vessel should be tamponaded with a sponge stick and an urgent thoracotomy be performed to control the hemorrhage.
The data regarding tumor seeding in the chest wall at the trocar sites has been controversial. All lung nodules and potentially malignant tissue can be removed in a retrieval sack without intra-operative spillage, even if that means extending the incision at the end of a difficult procedure.
Chest wall resection and reconstruction
Chest wall reconstruction techniques have been used since the 1940’s, when Watson and James described the use of fascia lata grafts for closure of chest wall defects. The most common indications for chest wall resection include primary or metastatic chest wall neoplasms, contiguous tumors from the breast and lung, traumatic lesions, radiation necrosis, osteomyelitis, etc. These produce partial or full-thickness defects. The location and size of the defect are of utmost importance in planning the operation.
The 3 main principles in this surgery are removal of devitalized tissue, restoration of a rigid chest wall to prevent a physiological fail, and healthy soft tissue coverage to seal the pleural space, protect the underlying viscera and vessels and prevent infection.
For large chest wall defects (>5 cm) synthetic or alloplastic materials can be used. Synthetic mesh like Marlex [knitted polypropylene], or thick 2-mm PTFE (polytetrafluoroethylene) soft tissue patch or polymethyl-methacrylate sandwich can be used to achieve sternal or rib stability. If the wound is contaminated, prosthetic material is usually not advised.
Muscle is the tissue of choice for soft tissue coverage and also in contaminated wounds. The various muscle transposition flaps that are commonly used include the latissimus dorsi flap based on the thoracodorsal neurovascular pedicle, the pectoralis major muscle based on the thoracoacromial bundle, the rectus abdominis muscle based on the internal mammary neurovascular bundle etc. Omental transposition is usually reserved for partial-thickness reconstruction or as a back-up for muscle transposition that has failed.
Approaches to the Pancoast tumors
In 1932, Henry Pancoast, a radiologist from Philadelphia described what he termed a "superior pulmonary sulcus tumor" that was associated with Horner’s Syndrome, rib destruction and atrophy of the hand muscles. These tumors are now described as entering the apex of the lung, at or above the level of the second rib with involvement of extrathoracic structures of the apical chest wall like the ribs, vertebral bodies, brachial plexus roots, the sympathetic nerves, and subclavian vessels.
With the extension of the definition of respectability and the use of induction chemo-radiotherapy followed by resection, surgery has now become an integral part of the multi-modality approach to this complex tumor. In the SWOG 9416 (North American Southwest Oncology Group) trial, the 5-year survival was 41% for all patients and 53% for complete resection.
The posterior approach was the initial approach and remained the mainstay in exposing most Pancoast tumors with the patient in the lateral decubitus position. The posterolateral thoracotomy is extended superiorly parallel to the scapula up to the seventh cervical vertebra at the base of the neck. A safe interspace, the fourth or fifth is entered, and a thorough exploration is performed to confirm resectability before extending the incision and dividing the trapezius and rhomboids posteriorly to dislocate and elevate the scapula and expose the first rib.
The scalene muscle are divided and the subclavian vessels are assessed and dissected. (Resection of the subclavian vessels is very difficulty from the posterior approach). En bloc chest wall resection is begun with anterior division of the ribs. Posterior disarticulation of the ribs to be resected requires an estimated understanding of the neurovascular anatomy of the spine.
Attention is then turned to resecting the first rib end appropriately managing the T1 nerve root. The other structures that sometimes need to be addressed include the superior stellate ganglion of the sympathetic nervous system, the vertebral arteries and on the left side the thoracic duct and the esophagus.
Once all the above structures at the base of the neck have been addressed and dissected, a standard upper lobectomy is performed to complete the en-bloc resection of the tumor. As always a mediastinal lymph node dissection should be performed to complete the procedure.
The anterior approach, popularized by Dartevelle et al, is better suited to the Pancoast tumors that invade more anteriorly (than the classic Pancoast tumors that invade posteriorly), as it allows better control of the subclavian vessels (see the image below).
Dartevelle’s technique involved a transclavicular approach with the incision following the anterior border of the sternocleidomastoid muscle in the neck and then extending laterally along the clavicle. Masaoka et al used a hemi-clamshell type incision with a partial sternotomy into the fourth intercostal space and supraclavicular transverse extension.
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