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Gharagozloo. Mini-invasive Surg 2020;4:8 I http://dx.doi.org/10.20517/2574-1225.2019.62 Page 7 of 13

Figure 1. View of the right pleural space. Cryoanalgesia probe being used to freeze the intercostals nerve

period. In addition, ibuprofen, 400-600 mg every 6-8 h, and indomethacin, 25 mg every 8 h, are used. COX-2
inhibitors are less available due to recent studies showing a potential increased rate of cardiovascular
thromboembolic events.

Local pain control
Several strategies have been used for local pain control in thoracic surgical patients.

Epidural analgesia
Epidural analgesia is a generally accepted form of analgesia in patients undergoing a thoracotomy. The
catheter is normally left in place for three or four days. Epidural catheters require constant attention. A
percentage of the catheters malfunction and require removal versus replacement. Patients are generally
not allowed to bathe or shower until the catheter is removed. Complications include neurologic injury and
[17]
bleeding around the spinal cord. Hypotension and urinary retention are common side effects . Although
epidural catheters can provide excellent pain relief, they are not commonly used with VATS because of the
time required for insertion, frequent side effects, and the relatively short period of effective use [18,19] . Earlier
ambulation and shorter hospital stay with VATS and robotic thoracic surgery preclude the use of epidural
catheter.

Cryoanalgesia
[19]
In 1999, Detterbeck et al. showed a decrease in perceived pain in patients undergoing VATS surgery with
cryotherapy of the intercostal nerves when compared to those undergoing VATS and pain management by
epidural catheters and analgesics. In a subsequent study, cryoanalgesia of the intercostal nerves was shown
to be effective in preventing post thoracotomy pain syndrome in patients who had undergone VATS
[20]
[Figures 1 and 2]. However, several studies have shown that cryoanalgesia is associated with long-term
complications. Most notably, cryoanalgesia has been associated with long-term neuralgia in the distribution
of the treated nerves in up to 12% of patients [20,21] . Although cryoanalgesia was associated with excellent
short- and long-term pain control following VATS, it was associated with irreversible hyperesthesia in 8%
of patients. It has been hypothesized that this was due to the inability to control the degree and depth of
the cold injury to the nerve, which resulted in irreversible damage and neuralgia [22,23] . As a result of this
experience, intercostal cryoanalgesia is no longer used in thoracic surgical patients.

Paravertebral blocks
Intraoperative paraverterbral (subpleural and intercostal) administration of long-acting local anesthetic
agents have been used. This technique uses individual intercostal blocks or placement of an indwelling