Definition

Post-thoracotomy pain syndrome (PTPS) is pain that recurs or persists at the incision site or in the dermatomal distribution of the intercostal nerves for longer than 2 months after thoracotomy [1–3]. Thoracotomies are used to access intrathoracic contents, such as the lung, esophagus, and heart. The most common indication for a thoracotomy is tumor resection. The classic thoracotomy consists of a posterolateral incision of the thorax, bisection of the latissimus dorsi and serratus anterior, separation of the ribs, disruption of the intercostal nerves, and pleural incision. The thoracotomy is regarded as one of the most painful surgical procedures performed [1–10]. The incidence of PTPS has a wide range (2% to 90%), but on average, approximately 40% of patients will have chronic postoperative pain [2,4]. PTPS is mild to moderate in 92% of cases; 50% of patients will have disruption in the capacity to perform daily activities. Sleep disruption occurs in 25% to 30%. Fortunately, severe disabling pain occurs in only 3% to 5% of patients with PTPS [5,6]. Predictive factors for development of PTPS include increased pain 24 hours postoperatively, female gender, preoperative opiate use, and radiation therapy [4,8].

Intercostal neuralgia is the most commonly implicated cause of chronic PTPS [1]. Other factors contributing to pain are outlined in Table 110.1. Recognizing that local muscle disruption of the serratus anterior and latissimus dorsi results in abnormal scapulohumeral mechanics, shoulder abnormalities are one of the common causes of functional loss after thoracotomy [7].

Symptoms

PTPS generally is manifested with symptoms of allodynia, dysesthesias, and lancinating pain typically attributed to intercostal neuralgia [4]. In addition, patients will have symptoms of achiness, pleuritic pain, and focal tenderness over the incision site [1,4]. Shoulder movement, deep breathing, and lying directly on the affected side can aggravate these symptoms [4]. Pain is frequently encountered with shoulder maneuvers and direct contact with the incision site and can be manifested as shoulder dysfunction and sleep disruption.

Physical Examination

The examination of the patient with PTPS includes inspection of the incision site and chest wall movement with respiratory excursion. Deep breathing maneuvers to elicit pleuritic pain are another component of the examination. Palpation over the incision site to evaluate for scar adherence, hypersensitivity, or intercostal nerve pain is the next component of the examination. The rib cage is disrupted with surgery and must be assessed for persistent fractures, costochondral avulsions, and costochondritis. Assessment of regional musculature for postoperative disruption, atrophy, and myofascial pain is important. Adhesive capsulitis and shoulder girdle dysfunction are factors in PTPS; therefore active and passive range of motion of the shoulder and scapulohumeral mechanics should be evaluated. Neurologic examination includes motor testing of the affected extremity compared with the unaffected side, evaluation for scapular winging, and assessment of the dermatomal distribution of the transected intercostal nerves.

Functional Limitations

PTPS results in daily activity limitations in 50% of those affected [5]. Ochroch and associates [9] identified functional decrement using the 36-item short form health survey (SF-36) in most patients at 4 to 48 weeks postoperatively. Shoulder restriction secondary to chest wall pain, adhesive capsulitis, and disruption of the serratus anterior and latissimus dorsi has been identified in 15% to 33% of post-thoracotomy patients at 1 year [7]. Shoulder restriction leads to limitations in sleep function, lifting capacity, and full range of motion activities of the shoulder girdle. In addition, functional limitations can be attributed to respiratory compromise related to surgery or underlying pulmonary disease.

Diagnostic Studies

The relevant diagnostic studies include baseline radiographs of the rib cage to evaluate for bone disruption. In addition, chest radiographs and computed tomography scans can be used to screen for intrathoracic processes, such as pleura-based dysfunction, pneumonia, and recurrence of primary malignant disease. A diagnostic intercostal nerve block can be performed to identify intercostal neuralgia.

The initial treatment of PTPS includes early aggressive management of pain. Preemptive analgesia is the concept of diminishing postoperative pain by disrupting pain pathways preoperatively [1]. Aspects of preemptive analgesia include thoracic epidural anesthesia, intercostal nerve blockade, opiates, and nonsteroidal anti-inflammatory drugs (NSAIDs) [1]. Thoracic epidural anesthesia has been shown to diminish acute postoperative pain in thoracotomy [10]. Balanced anesthesia with preoperative regional anesthesia, opiates, and NSAIDs diminishes the incidence of PTPS from 50% to 9.9% [2,4]. The surgical approach does have a bearing on postoperative pain. Smaller surgical incisions and muscle-sparing thoracotomies diminish postoperative pain [1]. In addition, early removal of chest tubes has been associated with diminished pain and improved pulmonary function [11].

Acute postoperative pain management includes thoracic epidural administration of opiates in combination with regional anesthesia and NSAIDs. Opiates alone decrease the incidence of PTPS to 23.4% [12]. In addition, opiates plus regional anesthesia decrease the incidence of PTPS to 14.8%. The opiates, anesthesia, and NSAIDs combine to diminish PTPS rates to 9.9% [12]. Further, early scar management, once healing is complete, can diminish long-term pain by reducing adhesions to chest wall structures and diminishing hypersensitivity. The primary technique to do this is gentle massage and repetitive stimulation of the incision site. Transcutaneous electrical nerve stimulation units have also been found to be effective in reducing PTPS [13,14].

Pharmacologic management of PTPS includes early postoperative use of opiates and NSAIDs in combination [2]. Delivery of topical anesthetics by patches (lidocaine) also can be used for pain control [2]. Management of chronic PTPS is usually through use of neuropathic pain medications. The only study specifically for PTPS used gabapentin and found that this was well tolerated and decreased pain in 73% of those studied; 42% of those studied had more than 50% pain relief [15]. Neuropathic pain medications used in other conditions that have not been studied in PTPS include amitriptyline and nortriptyline. If oral routes of pain control fail, intrathecal administration of opiates is an option.

Rehabilitation

The preoperative management of PTPS begins with nutritional assessment and augmentation. Patients with intrathoracic disease can frequently encounter nutritional issues as a result of their primary disease; it can be beneficial for postoperative recovery to maximize nutritional status. The second factor in preoperative management is to maintain or to obtain normal shoulder range of motion. As mentioned, shoulder dysfunction and muscle dysfunction occur in up to 33% of thoracotomy patients. Maximization of range, function, and muscle strength before surgery can reduce functional loss secondary to postoperative restriction.

Pulmonary rehabilitation is important in thoracotomy patients primarily because many have underlying pulmonary disease. Pulmonary rehabilitation preoperatively includes breathing techniques, energy conservation, instruction in medication use, secretion management, and aerobic endurance training. The objective is to reduce frequently encountered postoperative complications secondary to decreased depth of breathing, retention of secretions, atelectasis, and pneumonia [10]. Pulmonary rehabilitation begins postoperatively with breathing techniques, secretion management, and assisted coughing with stabilization of the disrupted thorax.

Scar mobilization is an important aspect of early pain relief. Scars can increase pain secondary to adherence to chest wall structures, underlying nerve entrapment, and restriction of range of motion of the shoulder. Early scar mobilization consists of gentle massage to maintain mobility of the incision and the soft tissue structures adjacent to the incision. Soft tissue massage techniques are not initiated until adequate wound healing has occurred.

Shoulder dysfunction is a common sequela of PTPS. The shoulder dysfunction has multiple factors, including muscle disruption, chest wall pain with shoulder movement, and myofascial pain. Surgical disruption of the latissimus dorsi and serratus anterior can lead directly to shoulder dysfunction. The serratus anterior stabilizes the scapula against the chest wall and aids in protraction. Normal shoulder abduction is limited without serratus anterior function. The latissimus dorsi is a powerful adductor of the arm. Latissimus dorsi restriction can lead to lack of forward flexion and abduction at the glenohumeral joint. The disruption of these two muscle groups is less of an issue with muscle-sparing procedures. The rehabilitation process is delayed primarily because of time for muscle continuity to return after disruption. The initial management includes gentle massage of the affected muscle group and pendulum exercises. This is followed by gentle active range of motion exercises that progress to passive range of motion exercises once full muscle continuity has been regained. Strengthening is the next process and can take up to a full year. Weakness in the latissimus muscle group may persist and requires attention and appropriate restrictions. The primary issue with the serratus anterior is obtaining normal scapular mechanics and normalizing scapulohumeral rhythm. This may require dedicated physical therapy by a therapist who understands shoulder mechanics. Shoulder rehabilitation may be delayed by postoperative restrictions. The standard restrictions are active range of motion only and no lifting of more than 10 pounds. These restrictions as standard practice are in place for 6 weeks after surgery. Full lifting as tolerated is typically not recommended until 12 weeks after surgery.

The next step in rehabilitation is regaining and perhaps surpassing of presurgical function with endurance training. Endurance training can include low-impact lower extremity exercise, such as walking and stationary biking once pain allows. The patient can progress to high-load activities (e.g., running, swimming, climbing) after full healing of the chest wall, typically at 12 weeks. The final step is return to work and vocational rehabilitation. It is important to address goals of the rehabilitation process early in management; this helps both physiatrist and patient to set goals that will maximize quality of life.

Procedures

Management of PTPS with interventional procedures consists of perioperative and chronic pain management. As mentioned, the perioperative management involves preemptive analgesia with regional anesthesia preoperatively [2,4]. Thoracic epidural anesthesia is the primary means of early postoperative management, and this typically consists of infusion of an opiate and an anesthetic [1]. Chronic PTPS management usually starts with intercostal nerve blockade [2]. Thoracic nerve root block and radiofrequency ablation of intercostal nerves are other procedures used for PTPS [2]. Long-term maintenance pain management can be accomplished with intrathecal opiate delivery and spinal cord stimulators [2].

Surgery

There are no surgical treatments for post-thoracotomy pain.

Potential Disease Complications

The potential complications of PTPS include postoperative respiratory dysfunction secondary to decreased depth of breathing, retention of secretions, and atelectasis [10]. In addition, persistent chest wall pain can result in decreased shoulder movement and adhesive capsulitis. Shoulder function also may be affected by the disruption of the serratus anterior and the latissimus dorsi, resulting in scapular dysfunction and glenohumeral dysfunction, respectively. In addition, sleep disruption, depression, loss of employment, and diminished functional and vocational capacities can be seen in PTPS.

Potential Treatment Complications

Complications of PTPS treatment include local complications from interventional procedures, including hematomas, infections, and nerve disruption. In addition, the use of opiates and NSAIDs postoperatively can lead to gastrointestinal dysfunction. The most common side effects identified with the use of gabapentin in this population are sedation (24%) and dizziness (6%) [13].