Segmental thoracic spinal anesthesia have introduced for cardiac surgery in adults and children in the early 1990's. Kowalewski et al., performed over 10000 cases of spinal injections without a single case of spinal/epidural hematoma or any neurological complications, also segmental thoracic spinal anesthesia has been used successfully for laparoscopic cholecystectomy and abdominal surgeries. It has some advantages when compared with general anesthesia and can be a sole anesthetic in breast cancer surgery with axillary lymph node clearance especially in critical cases. Among its advantages are the quality of postoperative analgesia, lower incidence of nausea and vomiting, and shorter recovery time, with the consequent early hospital discharge. The dose of the anesthetic is exceedingly low, compared with lumbar spinal anesthesia, given the highly specific block to only certain nerve functions along a section of the cord, there is no blockade of the lower extremities. This means that a significantly larger portion of the body experiences no venal dilation, and may offer a compensatory buffer to adverse changes in blood pressure intra-operatively. there was no recorded of neurological complications.The incidence of parasthesia in a study with 300 patients subjected to thoracic spinal puncture at T10-11 was 4.67% in the cut needle group and 8.67% in the pencil point needle group, similar to that reported in lumbar spinal anesthesia.The aim of the present study is the comparison between two sole regional anesthetic techniques, thoracic para-vertebral block and segmental thoracic spinal anesthesia in breast cancer surgery especially for critically ill patients.