268 Korean J Pain Vol. 23, No. 4, 2010 delivery. She again received lumbar epidural analgesia [8]. The third case involved a 31-year-old woman with the cervical SCS of CRPS II. She developed severe pain at the side of her abdomen at the junction between the electrode and the lead extender. This is different from the previously reported cases in that the generator was implanted in the anterior abdominal wall. The electrode end was placed at the T6 level. She developed new severe pain at the side of the abdomen at the junction between the epidural lead and the lead extender. Therefore, the lead extender was surgically cut with the generator switched off during the 28th week of gestation under local anesthesia. She went on to deliver a normal healthy baby at full term [9]. The last case, a 35-year-old woman with lumbar SCS for lum- bosacral pain was admitted for an urgent caesarean section. She had a Mallampati score of III and poor denti- tion with loose teeth. The electrodes were inserted at L2-3 and located at T8 and the generator was implanted in the left upper buttock. A caesarean delivery was planned, and spinal anesthesia was therefore performed below the SCS leads at the L4-5 level. A healthy infant was delivered [10]. In our case, the patient received a lumbar SCS im- plantation with CRPS I. She experienced a missed abortion 6 weeks after the procedure. There were no significant changes in the symptoms of CRPS or in the pattern of pain during pregnancy or after the abortion. We suspected three different possible causes for the abortion. First, her medications for chronic pain at that time may have been the cause [11]. The patient was receiving propranolol, mir- tazapine, tramadol, solifenacin succinate, mefenamic acid (category C; excretion into breast milk unknown), buspir- one HCl (category B; is not excreted in breast milk), ethyl loflazepate, and sodium tianeptine (not available). For cat- egory C drugs, it is known that "animal studies show some fetal risk but or no animal/controlled studies have been done." Hence, there is a considerable possibility that these drugs may have been the cause of the abortion [12]. Secondly, a literature search on the use of SCS in humans during pregnancy retrieved only one study [13]. Signifi- cantly elevated human placental lactogen and estriol serum levels were found as having a correlation to the onset of therapy at a specific week of gestation. This, however, is rarely the cause of birth defects or miscarriages. Thirdly, the possibility of natural abortion must be taken into account. The overall miscarriage rate is reported as 15-20%, which implies that 15-20% of recognized preg- nancies result in miscarriage [14]. The number of cases of SCS implantation continues to grow, and it is important to realize that there is always the chance to encounter a pregnant patient. The possibility of missed abortion, as mentioned previously, and other considerable facts related to pregnancy and delivery must be realized and kept in mind. Concerning the implantation of SCS, special attention must be paid for child-bearing woman. The generator is implanted posterior in the flank area away from the belt line or in the buttock area to avoid abdomen pain. If the patient complains of severe pain at the junction between the electrode and the lead extender, simple division of the electrode distal to the junction will resolve the problem. There is little guidance available regarding the perioper- ative anesthetic management of patients with SCS, but experience with deep brain stimulators, which use a similar technology, may be relevant [15-17]. Artifacts on electro- cardiography have been noted during SCS, deep brain stimulation and transcutaneous nerve stimulation [18]. The current location of the electrode, lead extender and gen- erator is ascertained by previous radiographs to assess the need for any special measures if neuraxial anesthesia is indicated. However, the location of the electrodes can change significantly. Thus, real-time ultrasound examina- tions may be useful. Potential risks include damage to the electrodes due to the spinal or epidural needle, introducer or catheter. If neuraxial anesthesia is performed, a metic- ulous sterile technique is essential. Although regional techniques are currently widely accepted, if possible gen- eral anesthesia is considered to be a better method in pa- tients with SCS. Surgical diathermy or electrocautery can damage the lead insulation, cause temporary suppression of the neurostimulator output, and lead to reprogramming of the neurostimulator [8,15]. Monopolar diathermy should be avoided when possible in the presence of SCS, as pain- ful electrical shocks have been reported; such shocks have not been described with generator turned off or when bi- polar diathermy is used. Bipolar diathermy appears to be safe if all components are distant from the implanted equipment [16]. Above all, a good outcome requires a multidisciplinary team approach, including obstetrics, neonatology, pain medicine and anesthesia, as was used in an earlier preg- nancy in our case. This will allow sufficient time to proceed to the next steps before any potentially urgent situation.