**5.3 Postoperative factors**

394 Front Lines of Thoracic Surgery

Intercostal nerves are primarily involved in the rib cage pain transmission. The incision of the skin, soft tissue and muscles triggers an inflammatory response. The retraction of the intercostal space, and sometimes the resection of the ribs themselves, increases the damage to the costovertebral and costotrasversal ligaments with the subsequent involvement of the

The intercostal nerve can be compressed by retractors or damaged during rib resection and closure of chest wall or can be trapped by sutures and healing processes. Nociception from mediastinic and diaphragmatic pleura is transmitted by different nervous pathways (phrenic and vagus nerves). This type of pain is deep and poorly localized. Moreover, this painful sensation triggered by diaphragmatic injury is also referred to the homolateral shoulder pain. Pleural drainage also produces deep pain due to both skin incision and

In addition to surgical injury, the breathing cycle constantly involves the damaged

The diagnosis of nerve injury is often associated with allodynia and/ or hyperalgesia plus

The type of incision is strictly associated to post-thoracotomy pain and damage of intercostal nerves (54). The posterolateral thoracotomy, sparing serratus anterior and trapezius muscles, seems to minimize damaging in intercostal nerves compared to the standard posterolateral thoracotomy. Consequently, this technique is associated with a reduction of pain and improvement mobility of the ipsilateral shoulder in the first

However, several studies have questioned these results in terms of both acute and chronic pain after one year. An anterior axillary approach has been proposed to reduce the painful symptoms, but the benefit was not still confirmed by the literature. The technique

Nevertheless, all the different surgical approaches described above, may lead either to acute and chronic pain. This finding may be firstly explained by frequent anatomical variants in the intercostal nerves course so that their integrity is not ensured by any surgical choice. Moreover, the surgical retractor, used in all the techniques, may probably play an important

The video-assisted thoracic surgery (VATS) seems to reduce the incidence of PTPS, probably because of multiple small incisions that produce a smaller nerve injury than open thoracotomy. However VATS does not preserve intercostal nerve from damage because the scope may crush nervous fibers against adjacent rib. Moreover the use of retractors to take away the lung section may also damage intercostals nerve (63-27). In conclusion VATS technique does not prevent the PTPS development but seems to reduce the PTPS incidence

Several prospective studies show that the most important predictor for the development of PTPS is the persistent post surgical pain which is strictly related to the severity of acute postoperative pain. Acute postoperative pain, in fact, is related to the amount of intercostal nerves damaged (55, 56). However, some studies found no clear relationship between PTPS and intensity of acute postoperative pain (1, 4, 10). The literature is not exhaustive because no study evaluates overall preoperative, intraoperative and postoperative factors which can influence the incidence of PTPS. Undoubtely, the strict pain control is mandatory in this

used for closure of the chest wall may play a role in the intercostal nerve damage.

**5.2.2 The intensity and duration of pain during the first postoperative day** 

parietal pleura (53).

pleural irritation.

seven postoperative days.

structures, enhancing the trigger of thoracic pain.

role in the damage of the intercostal nerves.

compared to muscle sparing incision (28)

kind of surgery.

numbness distributed in the area served by affected nerves.

#### **5.3.1 Social consequences**

The social impact of PTPS as capability to influence daily activites and consequently quality of life were investigated by several studies (4, 10, 13, 15, 20). Commonly the effects of PTPS are registered in the following activities: standing, sitting, getting up, sleep. Even if the pain intensity is moderate, normal daily activities could be hampered up to 50 % of cases and sleep disorders could be present in the 25% of patients (10); finally severe pain could be present in 8% and it's not relieved in more than 40% of cases (50). However, because of lack of right evaluation of this kind of disabilities, the exact impact of PTPS on social field must be better investigated.

#### **5.3.2 Disease relapse – chemo and radio therapy**

Keller et all (57) suggest that relapse of disease can uncontrovertibly rise PTPS incidence. However, even if this data is obvious and well comprehensible, much more data are needed to support this evidence. Moreover, since no data are available about the effects of chemo and radio-therapy on PTPS incidence, several studies must be encouraged to understand their role on PTPS incidence.
