Neuromodulation: Technology at the Neural Interface Received: October 14, 2014
Revised: February 9, 2015
Accepted: February 18, 2015
(onlinelibrary.wiley.com) DOI: 10.1111/ner.12314
High-Frequency Spinal Cord Stimulation and Pregnancy: A Case Report Caro Edelbroek, MANP; Michel Terheggen, MD Introduction: High-frequency spinal cord stimulation (HF SCS) is a relatively new modality of SCS. The present general advice concerning pregnancy and SCS, in general, is to turn the device off because of insufficient knowledge concerning the impact on the developing fetus. As HF stimulation generates higher energies, potential adverse fetal effects could be theoretically stronger. Case: This case report describes a 36-year-old woman who had two pregnancies with an active HF SCS system. Her first pregnancy ended in a miscarriage. During her second pregnancy, she continued stimulation treatment during the whole pregnancy. She gave birth to a healthy baby. Conclusions: This case describes both a miscarriage and the birth of a healthy baby in a patient treated with HF SCS. It is not possible to rule out that the HF SCS could have caused the miscarriage. Also, the birth of the healthy baby after the second pregnancy in which HF SCS was used the whole period, is not a valid reason to declare HF SCS and SCS, in general, safe during pregnancy. As no sufficient data are available, we must remain cautious about any unknown possible adverse effects or delayed adverse events because of SCS and maybe especially HF stimulation. All outcome data on pregnancies during all types of SCS ideally should be collected and analyzed. Keywords: Chronic pain, failed back surgery syndrome, high-frequency, pregnancy, spinal cord stimulation Conflict of Interest: The authors report no conflicts of interest.
INTRODUCTION
retically stronger. As far as the authors know, this is the first described pregnancy case in which HF SCS was used.
www.neuromodulationjournal.com
CASE This case report describes a 36-year-old woman with failed back surgery syndrome. In 2003, she underwent intervertebral disc replacement surgery. Unfortunately, the chronic back and leg pain she had before surgery was still a major problem after her back surgery. Extensive conservative therapy did not reduce the pain. In September 2011 an SCS system was implanted. The system consisted of two 50-cm leads with eight 5-mm electrodes and two 35-cm extensions connecting to an external HF pulse generator (Nevro Corp., Menlo Park, CA, USA). The tips of the leads were located at the superior margin of the T8 vertebral body and at the mid of T9 vertebral body in the dorsal epidural space. After a two-week trial period, she reported a significant pain reduction measured with a 100 mm visual analog scale (VAS) for both back and leg pain. The trail period was considered positive. A
Address correspondence to: Caro Edelbroek, Pres Kennedylaan 100, 6883 AZ Velp, The Netherlands. Email: [email protected] Pain Clinic Velp, Rijnstate Hospital, Velp, The Netherlands For more information on author guidelines, an explanation of our peer-review process, and conflict of interest informed consent policies, please go to http:// www.wiley.com/bw/submit.asp?ref=1094-7159&site=1 Funding Statement: There was no source or financial support.
© 2015 International Neuromodulation Society
Neuromodulation 2015; 18: 757–758
757
Spinal cord stimulation (SCS) is an accepted treatment for several pain syndromes. The literature concerning the safety of SCS during pregnancy is very limited. Therefore, patients are advised to stop the stimulation treatment the moment pregnancy is diagnosed. All manufacturers declare that SCS has not been evaluated in this subpopulation. When we searched the existing literature, ten case reports on this subject were found. All of the cases involved pregnant women with conventional SCS. All case reports reported no serious complications, abnormal pregnancies, or problems with the children. In 2012, a literature review was published from ten cases (1). In nine of the ten cases, no serious complications to either mother or child were found. Eight pregnancies were carried to term. There was one case in which an early miscarriage occurred six weeks after the SCS was implanted. The overall chance of a miscarriage in pregnancy without SCS in the first trimester is 10% (2). Another case report concluded SCS seemed to be safe during pregnancy (3). In a literature search using Pubmed, The Cochrane Library, and Mendeley, no data regarding high-frequency (HF) SCS in combination with pregnancy were found. HF SCS is a relatively new treatment introduced in 2010. It stimulates the spinal cord with 10,000 Hz. The literature reporting favorable results on outcome and safety from HF SCS is growing (4,5). The long-term effect from HF SCS on the nerve system is still unknown. HF SCS uses 10,000 Hz to stimulate the dorsal collum of the spinal cord while conventional SCS uses between 30 and 300 Hz. HF SCS therefore utilizes higher energies compared with conventional SCS. As a result, potential fetal adverse effects could be theo-
EDELBROEK & TERHEGGEN care for children. The data collection and follow up on the patient and the child is ongoing.
Table 1. VAS Pain Scores, Average Four-Day VAS Score.
VAS before SCS VAS in trial period SCS Pain reduction (%) VAS after one month VAS after 12 months VAS after 24 months
Leg
Back
83 14 83 1 38 40
58 4 93 6 33 35
SCS, spinal cord stimulation; VAS, visual analog scale.
rechargeable pulse generator (Nevro Corp.) was connected to the electrodes and implanted in her left buttock. The program used since implanting the system was 6–7 + 10,000 Hz/300 PW. This program was replaced during pregnancy by 6–7 + 10,000 Hz/ 300 PW cyclic two minutes off, 20 s on to reduce power use. The VAS pain scores after implanting the HF SCS system can be seen in Table 1. The patient’s first pregnancy occurred in June 2012. She turned off the SCS device immediately after she found out she was pregnant. This was at six weeks. Unfortunately, she had a miscarriage after eight weeks pregnancy. During these two weeks of pregnancy without active SCS treatment, she experienced a severe increase of back and leg pain. There was no further research or information about the reason this miscarriage occurred. In January 2013, she found out she was pregnant again. She now decided not to turn the device off, despite medical advice, because she did not think the HF SCS was the cause of her earlier miscarriage. The distributors of NEVRO (Joymed, JS Beuningen (gld), The Netherlands) also advised against active HF SCS treatment. There was a minor increase in back and leg pain reported in week 26 of the pregnancy. No reports of any additional pain in the gluteal area near the implantable pulse generator or other complications because of the SCS system were made. A gynecologist monitored the pregnancy. There were regular checkups every four weeks. No abnormalities were found with an ultrasound investigation at 20 weeks. Additional tests were not indicated. On October 10, 2013, at 38 weeks and one day, the patient gave birth to a baby girl with a C-section under spinal anesthesia. The SCS system was turned off before surgery. No complications were reported. The birth weight was 3930 g. The baby was checked by a pediatrician and was declared healthy. The development of the child was monitored until the moment this case report was published, and was normal according to the mother and the indicators from the Dutch general public health
CONCLUSIONS This article describes the case of a woman with two pregnancies and one childbirth during treatment with HF SCS. The first pregnancy ended with a miscarriage at eight weeks. During her second pregnancy, there were no adverse events, complications, or other problems. A healthy child was born and child development was normal as for now. It is impossible to rule out HF SCS as a cause for the miscarriage. Also, the birth of the healthy baby after the second pregnancy in which HF SCS was used the whole period is not a valid reason to declare HF SCS and SCS in general safe during pregnancy. As no sufficient data are available, we must remain cautious about any unknown possible triggers or delayed adverse events because of SCS and possibly especially HF SCS. All outcome data on pregnancies during all types of SCS ideally should be collected and analyzed. Perhaps, only after analyzing a substantial number of reported data would it be possible to give a more thorough advice on this precarious matter. Until then, the advice remains not to use this treatment during pregnancy. As far as the authors know, this is the first described pregnancy case in which HF SCS was used.
Authorship Statement Caro Edelbroek initiated and conducted the case report, prepared the draft for this article with important intellectual input and critical review from Dr. Terheggen.
How to Cite this Article: Edelbroek C., Terheggen M. High Frequency Spinal Cord Stimulation and Pregnancy. A Case Report. Neuromodulation 2015; 18: 757–758
REFERENCES 1. Fedoroff IC, Blackwell E, Malysh L, McDonald WN, Boyd M. Spinal cord stimulation in pregnancy: a literature review. Neuromodulation 2012;15:537–541. 2. Flikweert S, Wieringa-de Waard M, Meijer LJ, De Jonge A, Van Balen JAM. NHGstandard miscarriage. General Pract 2004;47:147–155. 3. Saxena A, Eljamal MS. Spinal cord stimulation in the first two trimesters of pregnancy: a case report and review of the literature. Neuromodulation 2009;12:281–283. 4. Van Buyten JP, Al Kaisy A, Smet J, Palmisanis S, Smith T. High frequency spinal cord stimulation for the treatment of chronic back pain patients: results of a prospective multicenter European clinical study. Neuromodulation 2013;16:59–65. 5. Kapural L. SENZA clinical trial results. Presented at the 18th Annual Meeting NANS 12 December 2014.
758 www.neuromodulationjournal.com
© 2015 International Neuromodulation Society
Neuromodulation 2015; 18: 757–758
Revised: February 9, 2015
Accepted: February 18, 2015
(onlinelibrary.wiley.com) DOI: 10.1111/ner.12314
High-Frequency Spinal Cord Stimulation and Pregnancy: A Case Report Caro Edelbroek, MANP; Michel Terheggen, MD Introduction: High-frequency spinal cord stimulation (HF SCS) is a relatively new modality of SCS. The present general advice concerning pregnancy and SCS, in general, is to turn the device off because of insufficient knowledge concerning the impact on the developing fetus. As HF stimulation generates higher energies, potential adverse fetal effects could be theoretically stronger. Case: This case report describes a 36-year-old woman who had two pregnancies with an active HF SCS system. Her first pregnancy ended in a miscarriage. During her second pregnancy, she continued stimulation treatment during the whole pregnancy. She gave birth to a healthy baby. Conclusions: This case describes both a miscarriage and the birth of a healthy baby in a patient treated with HF SCS. It is not possible to rule out that the HF SCS could have caused the miscarriage. Also, the birth of the healthy baby after the second pregnancy in which HF SCS was used the whole period, is not a valid reason to declare HF SCS and SCS, in general, safe during pregnancy. As no sufficient data are available, we must remain cautious about any unknown possible adverse effects or delayed adverse events because of SCS and maybe especially HF stimulation. All outcome data on pregnancies during all types of SCS ideally should be collected and analyzed. Keywords: Chronic pain, failed back surgery syndrome, high-frequency, pregnancy, spinal cord stimulation Conflict of Interest: The authors report no conflicts of interest.
INTRODUCTION
retically stronger. As far as the authors know, this is the first described pregnancy case in which HF SCS was used.
www.neuromodulationjournal.com
CASE This case report describes a 36-year-old woman with failed back surgery syndrome. In 2003, she underwent intervertebral disc replacement surgery. Unfortunately, the chronic back and leg pain she had before surgery was still a major problem after her back surgery. Extensive conservative therapy did not reduce the pain. In September 2011 an SCS system was implanted. The system consisted of two 50-cm leads with eight 5-mm electrodes and two 35-cm extensions connecting to an external HF pulse generator (Nevro Corp., Menlo Park, CA, USA). The tips of the leads were located at the superior margin of the T8 vertebral body and at the mid of T9 vertebral body in the dorsal epidural space. After a two-week trial period, she reported a significant pain reduction measured with a 100 mm visual analog scale (VAS) for both back and leg pain. The trail period was considered positive. A
Address correspondence to: Caro Edelbroek, Pres Kennedylaan 100, 6883 AZ Velp, The Netherlands. Email: [email protected] Pain Clinic Velp, Rijnstate Hospital, Velp, The Netherlands For more information on author guidelines, an explanation of our peer-review process, and conflict of interest informed consent policies, please go to http:// www.wiley.com/bw/submit.asp?ref=1094-7159&site=1 Funding Statement: There was no source or financial support.
© 2015 International Neuromodulation Society
Neuromodulation 2015; 18: 757–758
757
Spinal cord stimulation (SCS) is an accepted treatment for several pain syndromes. The literature concerning the safety of SCS during pregnancy is very limited. Therefore, patients are advised to stop the stimulation treatment the moment pregnancy is diagnosed. All manufacturers declare that SCS has not been evaluated in this subpopulation. When we searched the existing literature, ten case reports on this subject were found. All of the cases involved pregnant women with conventional SCS. All case reports reported no serious complications, abnormal pregnancies, or problems with the children. In 2012, a literature review was published from ten cases (1). In nine of the ten cases, no serious complications to either mother or child were found. Eight pregnancies were carried to term. There was one case in which an early miscarriage occurred six weeks after the SCS was implanted. The overall chance of a miscarriage in pregnancy without SCS in the first trimester is 10% (2). Another case report concluded SCS seemed to be safe during pregnancy (3). In a literature search using Pubmed, The Cochrane Library, and Mendeley, no data regarding high-frequency (HF) SCS in combination with pregnancy were found. HF SCS is a relatively new treatment introduced in 2010. It stimulates the spinal cord with 10,000 Hz. The literature reporting favorable results on outcome and safety from HF SCS is growing (4,5). The long-term effect from HF SCS on the nerve system is still unknown. HF SCS uses 10,000 Hz to stimulate the dorsal collum of the spinal cord while conventional SCS uses between 30 and 300 Hz. HF SCS therefore utilizes higher energies compared with conventional SCS. As a result, potential fetal adverse effects could be theo-
EDELBROEK & TERHEGGEN care for children. The data collection and follow up on the patient and the child is ongoing.
Table 1. VAS Pain Scores, Average Four-Day VAS Score.
VAS before SCS VAS in trial period SCS Pain reduction (%) VAS after one month VAS after 12 months VAS after 24 months
Leg
Back
83 14 83 1 38 40
58 4 93 6 33 35
SCS, spinal cord stimulation; VAS, visual analog scale.
rechargeable pulse generator (Nevro Corp.) was connected to the electrodes and implanted in her left buttock. The program used since implanting the system was 6–7 + 10,000 Hz/300 PW. This program was replaced during pregnancy by 6–7 + 10,000 Hz/ 300 PW cyclic two minutes off, 20 s on to reduce power use. The VAS pain scores after implanting the HF SCS system can be seen in Table 1. The patient’s first pregnancy occurred in June 2012. She turned off the SCS device immediately after she found out she was pregnant. This was at six weeks. Unfortunately, she had a miscarriage after eight weeks pregnancy. During these two weeks of pregnancy without active SCS treatment, she experienced a severe increase of back and leg pain. There was no further research or information about the reason this miscarriage occurred. In January 2013, she found out she was pregnant again. She now decided not to turn the device off, despite medical advice, because she did not think the HF SCS was the cause of her earlier miscarriage. The distributors of NEVRO (Joymed, JS Beuningen (gld), The Netherlands) also advised against active HF SCS treatment. There was a minor increase in back and leg pain reported in week 26 of the pregnancy. No reports of any additional pain in the gluteal area near the implantable pulse generator or other complications because of the SCS system were made. A gynecologist monitored the pregnancy. There were regular checkups every four weeks. No abnormalities were found with an ultrasound investigation at 20 weeks. Additional tests were not indicated. On October 10, 2013, at 38 weeks and one day, the patient gave birth to a baby girl with a C-section under spinal anesthesia. The SCS system was turned off before surgery. No complications were reported. The birth weight was 3930 g. The baby was checked by a pediatrician and was declared healthy. The development of the child was monitored until the moment this case report was published, and was normal according to the mother and the indicators from the Dutch general public health
CONCLUSIONS This article describes the case of a woman with two pregnancies and one childbirth during treatment with HF SCS. The first pregnancy ended with a miscarriage at eight weeks. During her second pregnancy, there were no adverse events, complications, or other problems. A healthy child was born and child development was normal as for now. It is impossible to rule out HF SCS as a cause for the miscarriage. Also, the birth of the healthy baby after the second pregnancy in which HF SCS was used the whole period is not a valid reason to declare HF SCS and SCS in general safe during pregnancy. As no sufficient data are available, we must remain cautious about any unknown possible triggers or delayed adverse events because of SCS and possibly especially HF SCS. All outcome data on pregnancies during all types of SCS ideally should be collected and analyzed. Perhaps, only after analyzing a substantial number of reported data would it be possible to give a more thorough advice on this precarious matter. Until then, the advice remains not to use this treatment during pregnancy. As far as the authors know, this is the first described pregnancy case in which HF SCS was used.
Authorship Statement Caro Edelbroek initiated and conducted the case report, prepared the draft for this article with important intellectual input and critical review from Dr. Terheggen.
How to Cite this Article: Edelbroek C., Terheggen M. High Frequency Spinal Cord Stimulation and Pregnancy. A Case Report. Neuromodulation 2015; 18: 757–758
REFERENCES 1. Fedoroff IC, Blackwell E, Malysh L, McDonald WN, Boyd M. Spinal cord stimulation in pregnancy: a literature review. Neuromodulation 2012;15:537–541. 2. Flikweert S, Wieringa-de Waard M, Meijer LJ, De Jonge A, Van Balen JAM. NHGstandard miscarriage. General Pract 2004;47:147–155. 3. Saxena A, Eljamal MS. Spinal cord stimulation in the first two trimesters of pregnancy: a case report and review of the literature. Neuromodulation 2009;12:281–283. 4. Van Buyten JP, Al Kaisy A, Smet J, Palmisanis S, Smith T. High frequency spinal cord stimulation for the treatment of chronic back pain patients: results of a prospective multicenter European clinical study. Neuromodulation 2013;16:59–65. 5. Kapural L. SENZA clinical trial results. Presented at the 18th Annual Meeting NANS 12 December 2014.
758 www.neuromodulationjournal.com
© 2015 International Neuromodulation Society
Neuromodulation 2015; 18: 757–758
