Unexpected Extrusion of the Implantable Pulse Generator of the Spinal Cord Stimulator

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Research Institute for Institute for Research 2 Case Report , Hye-Jin Kim 1

1,2 , Hyeonsoo Park ]. Pacemakers, which have a structure similar to that that to similar a structure have which ]. Pacemakers, 1,2 3 [ We report a case that unexpected extrusion of the IPG that a case of report We port, we received priorport, written we informed received for publi consent the patient. from cation rare rare have (IPG) component, pulse generator of the implantable [ of the chest extrudebeen to out reported removed and successfully identified SCS promptly was Prior re this to further withoutany complications. adverse 103 ------, Hyun-Su Ri , and Gyeong-Jo Byeon , and Gyeong-Jo eISSN 2383-7977 1,2 • 1,2 Despite significant technological advances in the implantable pulse generator generator pulse implantable in the advances technological significant Despite To prevent unexpected extrusion of IPG, it is necessary to consider in advance in advance it is necessary consider IPG, of to extrusion unexpected prevent To Complex regional pain syndrome; Devices; Necrosis; Neuropathic pain; Spinal Spinal pain; Neuropathic Necrosis; Devices; pain syndrome; regional Complex : After a car accident 4 years ago, a 55-year-old male who was diagnosed with complex with complex diagnosed was who male a 55-year-old 4 years ago, a car accident : After Department of Anesthesia and Pain Medicine, Pusan National University Yangsan National University Yangsan Pusan Medicine, and Pain Department of Anesthesia Ji-Uk Yoon 1 Medicine, National University School of Hospital, Pusan sure necrosis caused by continued compression of pocket site where a belt was frequently frequently was a belt where site pocket of compression by continued caused necrosis sure occurring. infection without successfully removed were leads the and IPG The tied. Conclusions: belt. the is pressed against site pocket the whether Keywords: stimulation. cord Yangsan Hospital, Yangsan, Korea Hospital, Yangsan, Yangsan Background: of IPG the of extrusion unexpected a case that report We can still occur. complications (IPG), any without successfully and removed identified promptly was (SCS) stimulation cord spinal complications. Case being IPG with the inserted with 2 leads, was SCS The leg. in his right pain syndrome local the of extrusion developed he years later, Four region. abdomen lower right in the implanted pres to related been have may extrusion unexpected This region. abdominal his from IPG Unexpected extrusion of the implantable pulse implantable of the extrusion Unexpected the spinal cord stimulator generator of - - A case report Eun-Ji Choi National University Pusan Science and Technology, Convergence of Biomedical Anesth Pain Med 2021;16:103-107 Med Pain Anesth https://doi.org/10.17085/apm.20054 pISSN 1975-5171 ]. Catastrophic complications, includ complications, ]. Catastrophic 2 [ June 23, 2020 June November 26, 2020 November ]. SCS has been reported to be a relatively safe and safe ]. SCS be been to a relatively reported has October 4, 2020 October 1 [ Spinal cord stimulation (SCS) var stimulation been used has treat to cord Spinal This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits which (http://creativecommons.org/licenses/by-nc/4.0) License Non-Commercial Attribution Commons Creative the of terms the under Access article is an Open This distributed cited. is properly work original the provided in any medium, reproduction and distribution, use, non-commercial unrestricted 2021 Anesthesiologists, Society of Korean © the Copyright tion, and infection sociated with SCS connection fail migration, lead include forma seroma site, the implant at pain breakage, lead ure, cades cades due to with complications several procedure reversible as complications Common properties. invasive minimally ious chronic neuropathic pain conditions for many de conditions for many pain neuropathic chronic ious E-mail: [email protected] [email protected] E-mail: 50612, Korea Korea 50612, 82-55-360-2758 Tel: 82-55-360-2149 Fax: Yangsan Hospital, Pusan National National Pusan Yangsan Hospital, Medicine, of School University Yangsan 20, Mulgeumeup, Geumoro Corresponding author author Corresponding M.D., Ph.D. Byeon, Gyeong-Jo Pain and Anesthesia of Department University National Pusan Medicine, Received Received Revised Accepted ing breakdown of the tissue overlaying implant site and ex site implant overlaying of the tissue breakdown ing very but possible, are the skin trusion of the device through Anesth Pain Med Vol. 16 No.1

CASE REPORT implantable pulse generator (IPG) was implanted. Before the operation, the implantation and incision sites were ex- A 55-year-old male with a height of 169.2 cm and a weight amined and marked in a sitting or standing position, the of 71.5 kg, who was diagnosed with complex regional pain subcutaneous pocket site for the IPG (Proclame™, St. Jude syndrome in the right leg, was visited our pain clinic to eval- Medical Neuromodulation Division) was made at the right uate SCS. He was in a car accident four years ago. There were lower abdominal wall. The IPG was implanted 2 cm deep no particular fractures at the time of the accident, and 3 in the right abdominal subcutaneous pocket site. The SCS months later, despite proper treatment, he suffered from was functioning well and showed no immediate post-sur- refractory, persistent pain, edema, temperature and color gical complications. changes, and hyperhidrosis of his right leg and foot. He was Two months later, he was generally satisfied with the taking various oral medications (acetaminophen, trama- pain relief; however, he reported that the stimulation did dol, gabapentin, duloxetine, baclofen, and oxycodone) and not come to the medial and sole of the foot, and hoped to had undergone several interventions (lumbar transforam- reduce the pain in the region using another cylindrical lead inal epidural steroid injection, lumbar sympathetic gangli- (Octrode, St. Jude Medical Neuromodulation Division) for on block, and lumbar sympathetic alcohol neurolysis), but spinal cord stimulation. Therefore, we performed an addi- there was no significant pain relief. He complained that his tional operation to insert the lead, and the lead tip was lo- baseline leg pain was 10 out of 10 in severity. The findings cated at the L1-L2 level (Fig. 1). He reported that electrical of magnetic resonance imaging, electromyography with stimulation was smooth on all parts of his right leg and nerve conduction study, bone densitometry, and 3-phase foot, and he experienced marked pain relief. The patient bone scan were non-specific. Digital infrared thermo- visited the clinic for follow-up evaluations every 1–2 graphic imaging of the lower extremities showed a body months after the procedure. He was very satisfied with the temperature 1–2.5°C lower in the right leg compared to the pain relief on his right leg. In daily life, he paid special at- left leg. tention not to press the IPG insertion site when sleeping or Prior to the trial implantation of the SCS device, he con- ducted a structural interview and the Minnesota Multipha- sic Personality Inventory by a psychologist. He was also trained about the system, its use, and the trial and implant procedures using printed materials and videos. After he was admitted to our hospital and had agreed to the operation, he was offered an SCS trial using a lead de- livery system device (Epiducer™, St. Jude Medical Neuro- modulation Division, USA). After the skin was anesthe- tized, a 14-gauge needle, a steerable guide wire was insert- ed into the L4/L5 epidural space using fluoroscopy. The needle was then removed, and the Epiducer™ was thread- ed over the guidewire and into the epidural space. After finding no regurgitation of cerebrospinal fluid or blood, the inner dilator and guide wire are removed. The S-Series paddle lead (St. Jude Medical Neuromodulation Division) was inserted via the Epiducer™, and the lead tip was locat- ed at the T10 to T12 level. The test simulation was per- formed in a range of 2 to 1,200 Hz, with typical pulse fre- quencies of 40 to 60 Hz. Stimulation covered the patient’s right leg and the dorsum of his foot. The lead was buried in the subcutaneous tissue. During the SCS trial, the pain de- creased to 4 out of 10. He reported greater than 50% relief Fig. 1. The lead tips were located at the T10-T12 (paddle lead) and L1-L2 (cylindrical lead) level on simple X-ray L-spine anterior-posterior of pain in his right leg. After 1 week of trial stimulation, the view.

104 www.anesth-pain-med.org KSPS ------105 ]. Its complications complications ]. Its 6 , 5 [ ]. Programming or therapy-re ]. Programming 9 , 8 DISCUSSION DISCUSSION The lower abdominal pocket site was thoroughly cleaned and and cleaned thoroughly was site pocket abdominal lower The ]. Biological complications include pain at the implant the implant at pain include complications ]. Biological 7 SCS has been an effective surgical procedure for improv SCS procedure been an effective surgical has an in have been to of SCS reported Complications have , 1 Fig. 3. Fig. wound the and removal, generator pulse implantable after debrided sutured. was site, allergic reaction, IPG seroma, infection, epidural fi epidural infection, IPG seroma, reaction, allergic site, head puncture-related dura hematoma, epidural brosis, spinal serious including nerve and more aches damage, injury [ cord and paralysis painful and of paresthesia loss include complications lated perform re-implantation of the SCS device later. the SCS of perform device later. re-implantation neuropathic with chronic patients suffering among ing occur despite can complications several However, pain. with signifi in the IPG, advances technological significant and rechargeable and weight, in both size decreases cant capabilities. studies several cidence of 30–40% in categories: main three divided into hardware-related, are Hard therapy-related. or programming and biological, or dis fracture lead include complications ware-related re migration of 5–9%, lead incidence connection reported 1.7% around portedin IPGand 27%, 0– of incidence failure [ ------Extrusion of implantable pulse generator pulse implantable Extrusion of ). After surgery, re ). After the patient ). The pocket did not show any any did not show pocket ). The Fig. 3 Fig. Fig. 2 ( ( The implantable pulse generator was extruded at the lower lower the at extruded was generator pulse implantable The At a routine follow-up, he complained of wound site ero of wound site he complained follow-up, a routine At www.anesth-pain-med.org Fig. 2. Fig. site. pocket abdominal medication and several conservative interventions. With With conservative and several interventions. medication we decided to and stable, all the risk of infection removed days. After removal of IPG, his right leg pain was 8-9 out of 8-9 out leg was pain his right of IPG, removal After days. with oral only 10 in severity, managed was as the pain moved during surgery were sent for aerobic and anaerobic and anaerobic during surgery for aerobic sent moved were was patient The negative. back returned which culture, for 14 antibiotic as postoperative prescribed cefazoline cleaned and debrided after the IPG removal, and the and the cleaned and debridedIPG the after removal, sutured wound was and the IPG leads re stimulator The uneventfully. covered consent, the patient had the stimulator leads and the IPG leads the stimulator had the patient consent, thoroughly was site pocket abdominal lower The removed. signs of active inflammation or infection. The IPG or infection. The re test inflammation of active signs completely were values functional the device’s that vealed written informed obtaining After within ranges. normal charge from the extrusion site from the eroded areas, and and areas, the eroded from the extrusion site from charge points several from taken were cultures microbiological region that around truding from his right lower abdominal wall. There was was There wall. abdominal lower right his truding from the entry with and exit of the IPG, around points erosion no dis was There beneath. of the tissue healing apparent On examination, the IPG had moved approximately 3cm 3cm approximately the IPG moved On had examination, part of metal ex was a 0.5 cm area and the pocket, below sion, and a metal piece was exposed from his lower ab his lower exposed piece and a metal sion, was from chills. and fevers denied having He for 2 days. wall dominal sation in the IPG pocket site when wearing a belt. Some when wearing in the IPG site a belt. pocket sation the that he complained his belt, when he tightened times, of the IPGskin felt under pressure. site during activities, however, he was engaged in agriculture in agriculture engaged he was however, during activities, with work a in his body bent hard doing always and was body sen noted a foreign occasionally position.He sitting Anesth Pain Med Vol. 16 No.1 or unpleasant paresthesia. These are less threatening and selection can minimize the incidence of complications. It can usually be resolved through programming, although is important to identify early signs of erosion before the de- on rare occasions can be removed due to therapy failure vice damages the skin. If the skin is not damaged, surgical [10]. modification of the pocket is often necessary to prevent Among the several complications mentioned above, IPG contamination and infection of the device. However, if the extrusion is a hardware-related complication, and it is a hardware is exposed, it should be assumed that the device very rare complication of SCS. In two cases, IPG extrusion is contaminated, and treatments generally involve a much was reported after implantation in the gluteal area [3,11]. more complicated procedure to remove all devices, includ- In one of these cases, the patient was a truck driver who ing IPG and leads [15]. had been driving for a long time for three months, causing In conclusion, extrusion of the IPG from the pocket site skin erosion in the buttocks and extruding the IPG. In the is very rare. In order to prevent this rare complication, pri- other case, an extrusion of the IPG in a sacral stimulator or to permanent SCS insertion, the clinicians should fully was due to rapid weight loss after the patient underwent consider the patient's age, occupational hazards, and daily gastric bypass surgery. Our report is the first case of extru- life habits that could cause excessive pressure on the IPG. sion after implantation of the IPG of a spinal cord stimula- And the skin of abdominal wall should be inspected care- tor into the abdominal wall. In a case similar to our report, fully at the site of the intended pocket, and the belt-tight- there are multiple case reports of pulse generator extrusion ening area should be examined in advance to see if all the of a pacemaker [4,12]. They were caused by the skin erod- SCS components, such as the IPG, will not be pressed by ing around the IPG insertion. The incidence of skin erosion the belt. A deep pocket (about 2–3 cm depth), instead of due to the underlying pacemaker generator has been esti- just a pocket under the skin, should be considered. In ad- mated to be approximately 0.8%. Factors predisposing skin dition, it is necessary to educate the patient not to habitu- erosion are the presence of a thin subcutaneous fat layer, ally touch the IPG insertion site with a sense of foreign tissue fragility in old-age patients, abrasive action exerted body. on the skin from external agents, pressure exercised from the device on the subcutaneous tissue and possible infec- ACKNOWLEDGEMENTS tions of the site [13]. The patient had been doing well after the operation. Oc- This work was supported by clinical research grant from casionally the patient complained of the discomfort of the Pusan National University Yangsan Hospital in 2019. IPG insertion when wearing a belt. The IPG were sutured to the subcutaneous fat layer of the abdominal wall to fix at CONFLICTS OF INTEREST the initial insertion site, but it seems that a tear occurred at the suture site. As a result, the IPG migrated downward No potential conflict of interest relevant to this article from the initial insertion site, and it seems that the down- was reported. ward migration was a little worse due to the compression of the belt. Skin erosion occurred due to compression of AUTHOR CONTRIBUTIONS the belt, and the IPG was extruded through this area. Whenever the patient wore a belt, he complained of dis- Conceptualization: Eun-Ji Choi, Gyeong-Jo Byeon. Writ- comfort due to the constant pressure on the IPG pocket ing - original draft: Eun-Ji Choi, Gyeong-Jo Byeon. Writing site. We should have carefully observed skin erosion during - review & editing: Ji-Uk Yoon, Gyeong-Jo Byeon. Investiga- follow-up. The early stages of skin erosion can develop ex- tion: Hyun-Su Ri, Hyeonsoo Park, Hye-Jin Kim. Supervi- posure of the pocket site, and even IPG migration and ex- sion: Ji-Uk Yoon. trusion. If the IPG size and configuration are not appropri- ate, excessive pressure can be placed on the subcutaneous ORCID tissue, and improperly sized pockets may result in the de- velopment of infection and dysfunction of the IPG [14]. Eun-Ji Choi, https://orcid.org/0000-0003-3731-0785 With a careful follow-up as well as a clear understanding of Hyun-Su Ri, https://orcid.org/0000-0002-7305-4144 potential complications and a careful approach to device Hyeonsoo Park, https://orcid.org/0000-0002-3376-3691

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