According to a previous review, the literature was inconsistent in defining chronic pain after mastectomy 38. To improve comparability between studies in the future, Jung et al suggested a time frame definition of chronic neuropathic syndrome classification based on the etiology.
The authors suggested that neuropathic pain syndromes due to breast surgery are considered chronic after 3 months and that shorter time frames should raise a consideration of pain associated with tumour recurrence. In Jung et al’s review, there were approximatly 21 studies with follow-up periods from 1-96 months which revealed the following:
Phantom breast pain prevalence is (3-44) per cent;
Intercostobrachial neuralgia (ICN) 16-39 percent for all breast cancer surgery;
Neuroma pain prevalence is (23-49) percent. 38
There were many trials (randomized, doubled-blinded, placebo-controlled) done to investigate the best neuropathic pain treatment algorithm. Many trials were included studying a lot of neuropathic conditions. The most studied oral medications were; anti-depressants, anticonvulsants, opioids, NMDA antagonists, mexilitine, topical lidocaine, cannabinoids, topical capsaicin, and glycine antagonist.
We here mention the most effective methods for controlling PMPS that were published in last few years:
One prospective randomized controlled clinical study was done in South Egypt Cancer Institute, titled (Analgesic efficacy of pregabalin in acute postmastectomy pain: placebo controlled dose ranging study) that published in Journal of Clinical Anesthesia, 2016. The conclusions was a single preoperative oral dose of pregabalin 150 mg is an optimal dose for reducing postoperative pain and morphine consumption in patients undergoing MRM 40.
Another important method is paravertebral block, as proved by study by Brian M. et.al. That published in 2015 and concluded that "Adding a multiple-day, continuous Ropivacaine infusion to a single-injection ropivacaine paravertebral nerve block may result in a decreased incidence of pain and pain-related physical and emotional dysfunction for 1 year after mastectomy 41.
Also, Pecs block (pectoral nerves block) which is an easy and reliable block inspired by the infra clavicular block approach and the intercostal abdominis plane blocks. Its technique as following, the pectoralis muscles are located under the clavicle then the space between the two muscles is dissected to reach the lateral pectoral and the medial pectoral nerves. The main indications are breast expanders and subpectoral prosthesis because the distension of these muscles is very painful 42.
A second version of the Pecs block was described, called ‘‘modified Pecs block’’ or Pecs block type II. This novel approach aims to block at least the pectoral nerves, the intercostobrachial, intercostals III-IV-V-VI and the long thoracic nerve. These nerves must be blocked to provide complete analgesia during breast surgery (Figure 3) 43.
Figure 3. anatomy of pectoral muscle
In a study published 2012 in Elsevier Doyma ‘‘modified Pecs’s block’’ or Pecs block type II was described. Using Ultrasound images that was very conclusive as the contrast was taken up by the axilla and reaches the thoracodorsal nerve area, passing above the serratus muscle and hence, the long thoracic nerve, was anesthetized with the clinical usefulness. This approach aims to block the axilla that is vital for axillary evacuation and the intercostal nerves, necessary for wide local excisions of the tumor. Two needle approaches used to perform the Pecs II block or ‘‘modified Pecs’s block’’ instead of one 44.
We must know that, Thoracic epidural and paravertebralblocks became the gold standard techniques to achieve this goal, but not every anesthesiologist is comfortable performing these procedures (Figure 4) 45.
Figure 4. U/S guided Thoracic epidural and paravertebral blocks 43
Other interventional method "interscalene brachial plexus block" which was proved by Kaya M et al, 2013 who evaluated the effects of interscalene brachial plexus block on postoperative pain relief and morphine consumption after modified radical mastectomy (MRM). Sixty ASA I–III patients scheduled for elective unilateral MRM under general anesthesia were included. Pain intensity was assessed with the visual analogue scale (VAS). Other parameters as morphine consumption, side effects of opioid, antiemetic requirement, and complications associated with interscalene block were recorded.VAS scores were significantly lower in interventional group, except in the first postoperative 24 h (p < 0.007). The patients without block consumed more morphine (group 1, 5 (0–40) mg; group 2, 22 (6–48) mg; p = 0.001) 46.
Until now paravertebral blocks and thoracic epidurals are the most effective and the gold standard pain treatment for breast cancer surgery. However, we questioned the effectiveness based on the fact that the brachial plexus nerves are the main component of this painful surgery and we described for the first time the use of pectoral nerve blocks with this indication 47.
We cannot ignore role of non-pharmacological methods of pain relief as preoperative explanation, education and Physical therapy techniques. As one of the best review that illustrated in detail effectiveness of postoperative physical therapy for upper-limb impairments after breast cancer treatment published in 2015 with the following recommendations 48:
1) First week post-op: low-intensity program involving elbow/wrist
2) 7-10 days post-op: gradually increase intensity passive mobilization (manual stretching, active exercises and increase muscle strength)
3) No recommendations can be made on length of time, content, intensity
4) Multifactorial therapy consisting of manual stretching and active exercises effectively treated impaired shoulder ROM 48.
4-Cold or heat
5-Splinting of wounds
6-Transcutaneous electrical nerve stimulation (TENS).
And sure the pharmacological methods of pain relief according to the ‘analgesic ladder’ introduced for treatment of cancer pain by the World Health Organization (WHO). It is formed of three steps according to intensity of pain. The first step involves the use of non-opioid +/- adjuncts (e.g. paracetamol, aspirin or non-steroidal anti-inflammatory drugs (NSAIDs). If pain is still uncontrolled, in addition to step 1 medication weak opioids (e.g. codeine, tramadol) can be added 49.
In moderate to severe pain or pain increasing in spite of step 2 treatment, stronger opioids are considered in addition. All these involve the concept known as multimodal analgesia. It is important to include the analgesic ladder in individual patient analgesic plan along with the adjunctive therapies. The analgesics act at different sites. Drugs that act at the site of injury and decrease pain associated with inflammatory reaction (e.g. NSAIDs), other drugs may alter nerve conduction (e.g. local anesthetics), some may modify transmission in the dorsal horn (e.g. opioids and antidepressants) while group of drugs may affect the central component and the emotional aspects of pain (e.g. opioids and antidepressants) 49.
Fourth step was added to WHO analgesic ladder which was interventional pain management such as stellate ganglion block (radiofrequency thermal neuro modulation) or local anesthetic injection of stellate ganglion block). Intervention pain management was advised to be done early before tumor spread or patient became deteriorated 51.
Opioid use could be associated with an increased incidence of opioid-related adverse drug events, including over sedation and respiratory depression 50. Further study are needed because opioid-related adverse drug events have been associated with an increase in overall cost, length of stay, and even decreased survival during in-hospital resuscitation 51.
It is frequently not possible to administer sufficient opioids alone, due to coexisting medical conditions, patient tolerance, allergies, or efforts to reduce total opioid use. In such cases, a multimodal approach to intravenous pain management must be employed. This may include the use of opioids, NSAIDS, and other adjuvant as needed to optimize patient pain control in the immediate postoperative period as a bridge until the patient can be transitioned to less potent oral medications 52.
And finally Minimizing damage to nerves during surgery Improved screening methods detect breast cancer at earlier stages. Earlier detection means smaller tumour sizes, which has made breast-conserving surgical treatments possible and widely used. These currently account for up to 40 per cent of breast cancer surgery 53.
Breast conserving techniques include lumpectomy, conservative breast surgery, wide local excision, partial mastectomy, segmentectomy, or tylectomy. Such approaches include reducing the number of axillary dissections required. Combining reduced surgical trauma with nerve preservation techniques may reduce the risk of sensory deficits and the occurrence of ICN 54, 55.
In this regard, the increased use of less invasive staging techniques such as sentinel lymph node biopsy has helped to reduce the number of patients undergoing axillary dissection and the resulting trauma to intercostobrachial nerves 56.