Dexmedetomedine and Ketamine in Erector Spinae Block for Postoperative Analgesia Following Mastectomy.

Persistent pain after breast cancer surgery is frequently observed in more than 60% of patients.The suboptimal management of perioperative pain can lead to the occurrence of persistent breast cancer pain syndrome and phantom breast pain. Dexmedetomidine, a novel α2-agonist with an eight-fold affinity for α2-adrenergic receptors (sedate and analgesic effects) as clonidine, while exerts much less α1-effects., has been found to significantly increase the duration of peripheral nerve blocks, with minimal systemic side effects.

Ketamine is a non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptors. It is used for sedation, premedication, induction, and maintenance of general anesthesia. Central, regional, and local anesthetic and analgesic properties have been reported for ketamine. Both can be used through Erector spinae plane block for postoperative pain control.

Persistent pain after breast cancer surgery is frequently observed in more than 60% of patients.The suboptimal management of perioperative pain can lead to the occurrence of persistent breast cancer pain syndrome and phantom breast pain.

A systematic review and meta-analysis of experimental studies showed that the provision of effective analgesia reduces both the number and incidence of metastases in experimental cancer models . Pain may influence body homeostasis and cancer progression by pain-related immune suppression.

General anesthesia is the conventional, most frequently used anesthetic technique in breast cancer surgical interventions. Various regional anesthetic techniques have also been used; these include local wound infiltration, thoracic epidural anesthesia, paravertebral block (PVB), thoracic spinal anesthesia, and more recently, ultrasound-guided interfacial plane blocks such as pectoral nerve (PECS) blocks type 1 and 2 and the serratus plane block (SPB). Recently introduced erector spinae plane block (ESPB) requires less technical expertise (easy), and may be a safe alternative to PVB. ESP block is described for treating thoracic neuropathic pain with encouraging results. ESP is a potential space deep to erector spinae muscle (ES), where the injected local anaesthetic (LA) spreads cranio-caudally up to several levels as the ES fascia extends from nuchal fascia cranially to the sacrum caudally (C7-T2 cranially and L2-L3 caudally), The block covers somatic and visceral pain during breast surgery blocks by blocking ventral rami, dorsal rami of spinal nerves, and rami communicans that transmit sympathetic fibers.

There is another potentially beneficial effects of regional anaesthesia and analgesia on perioperative outcomes, these include decreased opioids consumption , lower rate of post-operative pulmonary complications, decreased post-operative nausea vomiting (PONV) and decreased duration of post-anaesthesia care unit stay. Regional anaesthesia has long-term oncological outcomes as it is considered protective for cancer recurrence by its indirect and direct antiproliferative effects.

Over recent years, the addition of multiple types of additives to local anesthetics has been reported to improve analgesic effect of peripheral nerve block and regional blocks Dexmedetomidine, a novel α2-agonist with an eight-fold affinity for α2-adrenergic receptors (sedate and analgesic effects) as clonidine, while exerts much less α1-effects., has been found to significantly increase the duration of peripheral nerve blocks, with minimal systemic side effects.

Ketamine is a non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptors. It is used for sedation, premedication, induction, and maintenance of general anesthesia. Central, regional, and local anesthetic and analgesic properties have been reported for ketamine.

Eligibility Criteria:
Inclusion Criteria:

* ASA I or II .
* female aged between 18 to 65. Scheduled for elective modified radical mastectomy under general anesthesia.

Exclusion Criteria:

* Patient known to have allergy to any of the drugs used in the study.
* Infection at injection site.
* Coagulation disorders.
* severe heart ,liver or kidney disease.
* Unwillingness.