Relationship between number of prior lumbar spine surgeries and outcomes following spinal cord stimulator implantation: A multisite, retrospective pooled analysis.

OBJECTIVES: Lumbar spine surgery is a common procedure for treating disabling spine-related pain. In recent decades, both the number and cost of spine surgeries have increased despite technological advances and modification in surgical technique. For those patients that have continued uncontrolled back and/or lower extremity pain following lumbar spine surgery, spinal cord stimulation (SCS) has emerged as a viable treatment option. However, the impact of lumbar spine surgical history remains largely unstudied. Specifically, the current study considers the impact of number of prior lumbar spine surgeries on pain relief outcomes following SCS implantation. MATERIALS AND METHODS: We queried the electronic medical record of five separate pain practices for all patients who have undergone a SCS implant between January 1, 2017, and March 1, 2020. Inclusion criteria consisted of any patients with an SCS implant who underwent a prior lumbar spine surgery. The primary outcome was the mean calculated percentage pain relief in patients based on number of prior lumbar spine surgeries. RESULTS: There was a total of 1974 total SCS implant cases identified across five separate pain clinics. There was no difference in mean calculated pain relief in patients with one prior spine surgery versus those with two or more prior spine surgeries (28.2% vs. 25.8%, adjusted ß-coefficient -3.1, 95% CI -8.9 to 2.7, p = 0.290). Similarly, when analyzing number of spine surgeries as a continuous variable, there was no association between number of spine surgeries and calculated pain relief (adjusted ß-coefficient -1.5, 95% CI -4.0 to 1.1, p = 0.257). Additionally, after patients were stratified based on waveform, there was no association between number of prior lumbar spine surgeries (analyzed both as a categorical and continuous variable) and calculated percentage pain relief. CONCLUSIONS: This multicentered retrospective study found that there was no significant difference in pain scores in individuals who received SCS following one or more lumbar spine surgeries. Additionally, the waveform of the SCS device had no statistically significant impact on post-operative pain scores following one or more lumbar spine surgeries.

Preoperative hemoglobin A1c and perioperative blood glucose in patients with diabetes mellitus undergoing spinal cord stimulation surgery: A literature review of surgical site infection risk.

AIMS: The aim of our study was to review the surgical literature regarding the relationship between hemoglobin A1c (HbA1c), diagnosis of diabetes mellitus (DM), and risk of postoperative surgical site infection (SSI). METHODS: A librarian-assisted literature search was performed with two goals: (1) identify surgical publications related to SSI and HbA1c values, and (2) identify publications reporting infection risk with DM in spinal cord stimulation (SCS), intrathecal drug delivery systems (IDDS), and cardiovascular implantable electronic device (CIED) implantation surgeries. Published guidelines on perioperative management of DM are reviewed. RESULTS: We identified 30 studies reporting SSI and HbA1c values. The literature review indicated that for many surgical procedures, elevated HbA1c is not correlated to rate of SSI. We identified 16 studies reporting infection rates within DM cohorts following SCS, IDDS, and CIED implantation surgeries. The data reviewed did not indicate DM as an independent risk factor for SSI. CONCLUSION: Preoperative HbA1c levels in patients with a history of DM is not a singularly sufficient tool to estimate risk of perioperative infection in SCS implantation surgery. Published guidelines on perioperative management of DM do not suggest a specific HbA1c above which surgery should be delayed; intentional perioperative glycemic control is recommended.

Indirect Comparison of 10 kHz Spinal Cord Stimulation (SCS) versus Traditional Low-Frequency SCS for the Treatment of Painful Diabetic Neuropathy: A Systematic Review of Randomized Controlled Trials.

Spinal cord stimulation (SCS) is increasingly used to treat painful diabetic neuropathy (PDN). At the time of a recent meta-analysis in this field, data were only available from randomized controlled trials (RCTs) of traditional low-frequency SCS (LF-SCS). However, outcomes from high-frequency 10 kHz SCS treatment are now available. Our study aimed to systematically review the contemporary evidence for SCS in patients with lower limb pain due to PDN and include an indirect comparison of the high- and low-frequency modalities. We searched the PubMed/CENTRAL databases up to 18 August 2022, for peer-reviewed RCTs of SCS that enrolled PDN patients with lower limb pain symptoms. The quality of the evidence was assessed with the Cochrane Risk of Bias tool. Using SCS treatment arm data from the RCTs, we indirectly compared the absolute treatment effect of 10 kHz SCS and LF-SCS. Results are presented in tables and forest plots. This systematic review was reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines. Three RCTs met our eligibility criteria, including the recent 10 kHz SCS RCT (N = 216, 90 implanted) and 2 others that examined LF-SCS (N = 36, 17 implanted; N = 60, 37 implanted). Our analysis of 6-month data found clinically meaningful pain relief with each SCS modality. However, significantly greater pain reduction was identified for 10 kHz SCS over LF-SCS: average pain reduction in the 10 kHz SCS cohort was 73.7% compared with 47.5% in the pooled LF-SCS group (p < 0.0001). In the permanent implant subset, the 50% pain reduction responder rate was 83.3% in the 10 kHz SCS cohort versus 63.0% in the pooled LF-SCS group (p = 0.0072). The overall risk of bias of each included RCT was deemed high, mainly due to the absence of patient blinding. Our analysis indicates that paresthesia-free 10 kHz SCS can provide superior pain relief and responder rate over LF-SCS for managing PDN patients refractory to conventional medical management.

Explantation of 10 kHz Spinal Cord Stimulation Devices: A Retrospective Review of 744 Patients Followed for at Least 12 Months.

OBJECTIVES: High-frequency 10 kHz spinal cord stimulation (10 kHz-SCS) has achieved analgesia superior to traditional SCS in a number of studies. However, there is concern regarding long-term outcomes of 10 kHz-SCS. Prior work has suggested that explant rates are higher with 10 kHz-SCS. Our primary objective was to determine the explant rate of 10 kHz-SCS in a large patient cohort from multiple centers followed for at least 12 months after implant surgery. MATERIALS AND METHODS: We performed a retrospective chart review of all patients who received a 10 kHz-SCS implant before July 1, 2019. We abstracted patient demographics, implant date, primary site of pain, implant indication, explant date, and reason for explant. A total of 744 patients were included in the study analysis. RESULTS: Average age of the overall cohort was 65.53 years and 407 (54.7%) were women. Average follow-up for all patients was 793 days. There were a total of 76 explants (10.2%). The most common reason for explant was loss of efficacy, which accounted for 39 explants (51.3% of total explants, 5.2% of overall cohort). Female sex and radiculopathy as the SCS indication were associated with statistically significant decreased risk of 10 kHz-SCS explant. CONCLUSIONS: We found 10 kHz-SCS explant rates to be similar to prior reported explant rates for traditional SCS devices. Patient-related factors including female sex and radiculopathy as the primary SCS indication may be protective factors against explantation.

Title: Quantifying the change of spasticity after intrathecal baclofen administration: A descriptive retrospective analysis.

OBJECTIVES: Exploratory research quantifying the change of spasticity among patients who underwent baclofen intrathecal drug delivery system (IDDS) implantation. PATIENTS AND METHODS: 88 patients with a baclofen IDDS were identified. Patient characteristics, spasticity scores pre/post intrathecal baclofen test dose, and IDDS perioperative implantation records were collected. The primary outcome was to quantify the extent to which there was a change in Modified Ashworth Scores (MAS) pre/post-intrathecal baclofen test dose administration. Secondary outcomes included the prevalence of perioperative IDDS implantation complications. RESULTS: The mean age at IDDS implant was 44.2 years (range, 19-71), and 62.5% were male. 45.5% had spasticity of spinal cord origin, 9% of cerebral origin, and 45.5% of other upper motor neuron dysfunction. Reduction of MAS in the spinal cord origin group was 2.6 (mean, 3.5 to 0.9), cerebral origin group was 2.9 (mean, 3.3 to 0.4), and other origin group was 2.5 (mean, 3.6 to 1.1). In all patients, post dural puncture headache was the most commonly reported complication at 22.7%. CONCLUSION: This report offers novel findings documenting a quantifiable change of at least two points on the MAS before and after intrathecal baclofen test dose as statistically significant and could prove to be useful information to enhance the decision making process to proceed with intrathecal baclofen beyond assessment of functional abilities.

Utilization of Leads After Permanent Implant in Spinal Cord Stimulator Systems.

OBJECTIVE: The goal of this study was to determine the frequency and clinical indications associated with implantation of single vs. dual percutaneous lead spinal cord stimulator (SCS) systems and to look further into how these leads are utilized for treatment. MATERIALS AND METHODS: A retrospective cohort analysis of all patients undergoing SCS implantation between January 2001 and December 2013 with a minimum of 2 years of clinical follow-up was performed. Number of trial leads and implanted leads was recorded. For patients with dual-lead systems, it was noted if and when the second lead was used, along with the clinical indication for lead activation. RESULTS: In the 259-patient cohort, 15.8% (n = 41) patients underwent placement of a single-lead system, 83.0% (n = 215) underwent placement of a dual-lead system, and 1.2% (n = 3) underwent placement of 3-lead systems. Placement of dual-lead systems was similar among all indication groups. Of those patients with a dual-lead system in place, 88.1% utilized both leads and average time to programming of the second lead was 2.3 months. The most common reason to activate the second lead was inadequate stimulation coverage. Five of the 41 patients with single-lead systems underwent an additional surgery to implant a second lead due to inadequate stimulation with 1 lead. CONCLUSIONS: To our knowledge this is the first descriptive analysis of the frequency of single- and dual-lead SCS systems. This report indicates that dual-lead systems are most often placed and both leads are required for optimal patient therapy.

Outcomes of C1-2 joint injections.

OBJECTIVE: Intra-articular injections of the C1-2 joint are an effective therapeutic option for pain generated from degenerative and inflammatory conditions affecting the joint. Limited information exists about the adverse events (AEs) associated with these injections. The primary aim of this study is to describe the frequency and type of AEs associated with C1-2 joint injections. The secondary aim is to identify clinical factors associated with the occurrence of AEs of C1-2 joint injections. DESIGN/METHODS: A retrospective chart review was conducted on all C1-2 joint injections performed at the Mayo Pain Medicine Clinic in Rochester, MN, from January 1, 2005 through July 31, 2015. AE data were extracted from procedural and post-procedural clinical notes. Analysis was conducted to determine correlations between any AE and demographic and clinical characteristics. Using univariate and multivariate logistic regression analyses, associations were determined. RESULTS: From January 1, 2005 to July 31, 2015, 135 C1-2 injections were performed on 72 patients. Overall, at least 1 AE was reported in 18.5% of the injections. The most common AEs were post-procedural increase in pain and procedural vascular contrast uptake. There was a significant association between AE occurrence and greater pre-procedural maximum pain score. CONCLUSIONS: AEs from C1-2 joint injections occurred commonly, but there were no persistent or serious AEs associated with these injections. The data also demonstrate that patients with higher pre-procedural maximum pain scores are more likely to experience an AE.

Bleeding and Neurologic Complications in 58,000 Interventional Pain Procedures.

BACKGROUND AND OBJECTIVES: Interventional pain procedures are commonly performed on patients receiving antiplatelet therapy. However, there is limited evidence to support or refute the safety of this practice. The goal of this investigation was to assess the rate of bleeding complications in a large cohort of patients undergoing intermediate- and low-risk pain procedures, with a specific focus on antiplatelet and anticoagulant medication use and baseline coagulation abnormalities. METHODS: This is a retrospective cohort study of adult patients undergoing low- and intermediate-risk pain procedures from 2005 through 2014 by the division of pain medicine at a single academic tertiary care center. Baseline characteristics, antiplatelet and anticoagulant medication use, coagulation parameters, and procedural details were extracted from the electronic medical record. The primary outcome was a bleeding-related complication requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days. The secondary outcome was the presence or absence of a periprocedural red blood cell transfusion occurring within 72 hours of needle placement. RESULTS: A total of 58,066 procedures were performed on 24,590 unique patients. Preprocedural aspirin or nonsteroidal anti-inflammatory drug therapy was present for 17,825 procedures (30.7%). Sixteen procedures were associated with perioperative red blood cell transfusion (0.03%), with no difference based on preprocedural nonsteroidal anti-inflammatory drug, including aspirin, or other anticoagulation use (P = 0.107). Five patients (0.009%) had a neurologic complication requiring further evaluation, of which 2 were likely related to procedural bleeding. CONCLUSIONS: Bleeding complications are rare in patients undergoing low- or intermediate-risk pain procedures even in the presence of antiplatelet medications. This is consistent with recently released guidelines.

Spinal Cord Stimulator Related Infections: Findings From a Multicenter Retrospective Analysis of 2737 Implants.

INTRODUCTION: Surgical site infection is a potential complication of spinal cord stimulator (SCS) implantation. Current understanding of the epidemiology, diagnosis, and treatment of these infections is based largely on small clinical studies, many of which are outdated. Evidence-based guidelines for management of SCS-related infections thus rely instead on expert opinion, case reports, and case series. In this study, we aim to provide a large scale retrospective study of infection management techniques specifically for SCS implantation. METHODS: A multicenter retrospective study of SCS implants performed over a seven-year period at 11 unique academic and non-academic institutions in the United States. All infections and related complications in this cohort were analyzed. RESULTS: Within our study of 2737 SCS implant procedures, we identified all procedures complicated by infection (2.45%). Localized incisional pain and wound erythema were the most common presenting signs. Laboratory studies were performed in the majority of patients, but an imaging study was performed in less than half of these patients. The most common causative organism was Staphylococcus aureus and the IPG pocket was the most common site of an SCS-related infection. Explantation was ultimately performed in 52 of the 67 patients (77.6%). Non-explantation salvage therapy was attempted in 24 patients and was successful in resolving the infection in 15 patients without removal of SCS hardware components. DISCUSSION: This study provides current data regarding SCS related infections, including incidence, diagnosis, and treatment.

Spinal Cord Stimulator Implant Infection Rates and Risk Factors: A Multicenter Retrospective Study.

OBJECTIVES: Spinal cord stimulation is an evidence-based treatment for a number of chronic pain conditions. While this therapy offers improvement in pain and function it is not without potential complications. These complications include device failure, migration, loss of therapeutic paresthesia, and infection. This article looked to establish a modern infection rate for spinal cord stimulators, assess the impact of known risk factors for surgical site infections and to determine the impact of certain preventative measures on the rate of infection. METHODS: After institutional review board approval, a multisite, retrospective review was conducted on 2737 unique implants or revisions of SCS systems. Patient demographics, risk factors including diabetes, tobacco use, obesity, revision surgery, trial length, implant location, implant type, surgeon background, prophylactic antibiotic use, utilization of a occlusive dressing, and post-operative antibiotic use were recorded and analyzed. RESULTS: The overall infection rate was 2.45% (n = 67). Diabetes, tobacco use, and obesity did not independently increase the rate of infection. Revision surgeries had a trend toward higher infection rate; however, this did not meet statistical significance. There was no difference in the rate of infection between implants performed by physicians of different base specialties, cylinder leads vs. paddle leads, or between different prophylactic antibiotics. Implants performed at academic centers had a higher rate of infection when compared to implants performed in nonacademic settings. When patients received an occlusive dressing or post-operative antibiotics they had a lower rate of infection. CONCLUSIONS: The infection rate (2.45%) reported in this study is lower than the previously reported rates (3-6%) and are on par with other surgical specialties. This study did not show an increased rate of infection for patients that used tobacco, had diabetes or were obese. It's possible that given the low overall infection rate a larger study is needed to establish the true impact of these factors on infection. In addition, this study did not address the impact of poorly controlled diabetes mellitus (elevated hemoglobin A1c) vs. well-controlled diabetes. It can be concluded from this study that utilizing an occlusive dressing over the incision in the post-operative period decreases the rate of infection and should become the standard of care. This study also demonstrated the positive impact of post-operative antibiotics in decreasing the rate of infection. Studies in other surgical specialties have not shown this impact which would suggest that further research is needed.

Bleeding Complications in Patients Undergoing Intrathecal Drug Delivery System Implantation.

INTRODUCTION: Intrathecal drug delivery systems (IDDSs) have dramatically improved analgesia and the functional status of cancer patients and those with chronic pain states. However, given the close proximity to the neuraxis and frequent concomitant use of antiplatelet or anticoagulant medications, this intervention is not without risk. The goal of this investigation was to determine the incidence of bleeding complications following IDDS placement. METHODS: This is a retrospective review from 2005 through 2014 of adult patients undergoing IDDS implantation or revision at a tertiary care center. The primary outcome was a bleeding-related neurological complication requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days. RESULTS: A total of 247 procedures were performed on 216 unique patients. Patients received aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) within seven days of needle placement for 64 procedures (25.9%). A preprocedural platelet count or international normalized ratio (INR) was available within 30 days for 138 procedures (55.9%). Of these, two patients had a platelet count lower than 100 x 109/L and one patient had an INR of 1.5 or higher at the time of the procedure. One neurological complication was identified (0.4%) that was not related to procedural bleeding. Similarly, three patients (1.2%) received a periprocedural red blood cell transfusion, none of which were related to procedural bleeding. CONCLUSION: No cases of bleeding-related neurological complications were identified following IDDS placement or revision, including in those receiving aspirin or NSAIDs. Future investigations with larger numbers are needed to further explore the safety of antithrombotic therapy continuation or discontinuation periprocedurally.

Surgical Site Infections in Cancer Patients with Intrathecal Drug Delivery Devices.

Objectives: Our purpose was to determine the incidence of surgical site infection (SSI) in cancer patients receiving an intrathecal drug delivery system (IDDS) and compare that rate with the incidence of SSI in the general population receiving an IDDS or spinal cord stimulator. We attempted to describe risk factors for SSIs in cancer patients treated with IDDS in terms of exposure to cancer treatments. Design: Retrospective review. Setting: Large tertiary care center. Patients: Cancer patients receiving an IDDS in 2006-2013. Methods: The incidence of SSI was determined according to the US Centers for Disease Control and Prevention definition. Medication regimens and current cancer treatment were investigated to identify immunocompromised patients during IDDS placement. Microbacteriology, treatment, and overall outcomes were investigated. Results: Sixty-four patients had an IDDS implanted in 2006-2013. SSI developed in four patients (6.2%). All four patients had received chemotherapy or radiotherapy within three months before implantation. Three of the three were receiving dexamethasone, and three of the four required explantation of the IDDS. Conclusion: The incidence of SSI was at the upper end of the published infection rates for IDDS. The risk of SSI may be increased in this population because of factors that alter the patient's immune status, including concomitant corticosteroid use, radiotherapy near the SSI, and presence of immunomodulators. The identification and mitigation of certain risk factors for this population may prevent infection in future patients.

High-Frequency Spinal Cord Stimulation in a Patient with an Implanted Cardiac Device.

BACKGROUND: New advances in spinal cord stimulation have led to improved treatment of patients suffering from chronic pain. While the overall safety of newer stimulation devices has been established, no published reports exist regarding safety considerations when these devices are implanted in patients with a preexisting cardiac device. CASE REPORT: An 83-year-old man with a history of out-of-hospital cardiac arrest secondary to an episode of ventricular fibrillation underwent automated implantable cardiac defibrillator placement. Concomitantly, he suffered from intractable chronic low axial back pain and was deemed a candidate for high-frequency (10 kHz) spinal cord stimulation (SCS). Cardiac monitoring during SCS trial and implantation was performed with no interference noted. Following high-frequency SCS implantation, the patient was observed to have significant pain relief with functional improvement. DISCUSSION: While others have reported safety during traditional SCS in patients with implanted cardiac devices, this is the first case report to describe safe and effective use of high-frequency SCS in a patient with an implanted cardiac device.

Treatment of Refractory Postdural Puncture Headache after Intrathecal Drug Delivery System Implantation with Epidural Blood Patch Procedures: A 20-Year Experience.

A recent publication reported the incidence of postdural puncture headache (PDPH) in conjunction with intrathecal drug delivery system (IDDS) implantation to be nearly 23 percent. Many patients responded to conservative measures but a percentage needed invasive treatment with an epidural blood patch (EBP). There is limited data to describe the technical details, success rates, and complications associated with EBP in this population. This study aims to provide a retrospective report of EBP for patients suffering from PDPH related to IDDS implantation. A chart review established a cohort of patients that required EBP in relation to a PDPH after IDDS implantation. This cohort was evaluated for demographic data as well as details of the EBP including technical procedural data, success rates, and complications. All patients received a trial of conservative therapy. Standard sterile technique and skin preparation were utilized with no infectious complications. The EBP was placed below the level of the IDDS catheter in 94% of procedures. Fluoroscopy was utilized in each case. The mean EBP volume was 18.6 cc and median time of EBP was day 7 after implant. There were no complications associated with EBP. EBP appears to be an effective intervention in this subset of PDPH patients.

Bleeding Complications in Patients Undergoing Percutaneous Spinal Cord Stimulator Trials and Implantations.

INTRODUCTION: Spinal cord stimulators (SCS) are indicated for the management of multiple pain states with strong evidence. Recent guidelines recommend discontinuing aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) for the described procedures. The goal of this investigation is to assess the rate of bleeding and neurologic sequelae in patients undergoing SCS trials and implantation. METHODS: This is a retrospective review from 2005 through 2014 of all patients 18 years or older undergoing the following procedures: Percutaneous SCS implantations, SCS revisions, and SCS trials. Baseline characteristics, antiplatelet and anticoagulation medications, coagulation parameters, and procedural details were extracted. The primary outcome was the presence of a bleeding complication within 31 days of the procedure requiring emergency medicine, neurology, or neurosurgical evaluation. The neurological complication was independently categorized for its potential relationship to procedural bleeding, and periprocedural red blood cell transfusion requirements were analyzed as a secondary outcome. RESULTS: A total of 642 percutaneous SCS procedures were performed on 421 unique patients, including 346 SCS trials, 255 SCS implantations, and 41 revision surgeries. Patients had received aspirin or NSAIDs within 7 days of needle placement for 101 procedures (15.7%). There were no bleeding or neurological complications identified in this cohort. CONCLUSION: Although the incidence of epidural hematoma is low, the development of bleeding complications following SCS lead placement can be devastating. In the present investigation, we identified no cases of epidural hematoma following percutaneous SCS lead placement, including more than 100 patients receiving aspirin or NSAIDs. Future investigations with larger numbers are needed to better define the relationships between periprocedural aspirin and NSAID utilization and bleeding complications.

Bleeding Complications in Patients Undergoing Celiac Plexus Block.

BACKGROUND AND OBJECTIVES: Celiac plexus blockade has known risks including bleeding and neurologic injury because of the close proximity of vascular and neuraxial structures. The aim of this study was to determine the incidence of bleeding complications in patients undergoing celiac plexus block (CPB), with an emphasis on preprocedural antiplatelet medication use and coagulation status. METHODS: This is a retrospective study from 2005 to 2014 of adult patients undergoing CPB by the pain medicine division at a tertiary care center. The primary outcome was red blood cell (RBC) transfusion within 72 hours of needle placement, with a secondary outcome of bleeding complications requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days. RESULTS: A total of 402 procedures were performed on 298 unique patients, with 58 patients (14.4%) receiving aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) preoperatively. Five patients (1.2%) received RBC transfusion within 72 hours, of which one had received preprocedure NSAIDs. A platelet count measured within 30 days was available for 268 patients, with 7 patients (2.6%) having platelet counts of 100 × 10/L or less at the time of needle placement. A total of 187 patients had a valid preoperative international normalized ratio (INR), with 9 (4.8%) having an INR of 1.5 or higher (range, 1.5-2.6). One patient (11.1%) required RBC transfusion compared with an RBC transfusion rate of 2.3% (4 of 178) in those with normal INR (P = 0.221). We identified no bleeding complications requiring emergency medicine, neurology, or neurosurgical evaluation. CONCLUSIONS: This study suggests that CPBs may be safely performed in patients receiving aspirin and/or NSAID therapy.

Safety of Lumbar Spine Radiofrequency Procedures in Patients Who Have Posterior Spinal Hardware.

OBJECTIVE: The purpose of this study was to determine whether the energy generated by an active radiofrequency (RF) cannula adjacent to lumbar spine hardware could result in heating of the hardware. DESIGN: Prospective study. SETTING: Tertiary care medical center. SUBJECTS: Six patients with lumbar facet joint pain at the level adjacent to lumbar spine fusion hardware were studied. METHODS: A total of 10 lumbar medial branch nerve radiofrequency lesion procedures were performed on six patients. A temperature probe was placed on the fusion hardware to continuously monitor the temperature of the hardware throughout the RF procedure. RESULTS: The temperature of the fusion hardware increased in six of the 10 RF lesion procedures. During two of the procedures, the temperature rose rapidly to 42°C, at which time the procedure was ceased at that level. CONCLUSION: This study demonstrated that radiofrequency lesioning to treat symptomatic facet joint pain in patients who have adjacent posterior lumbar fusion hardware may result in heat energy being transferred to the adjacent hardware. This may increase the risk of injury to the patient. Monitoring for a temperature increase is easily accomplished by inserting a temperature probe onto the surface of the hardware.

Patient Outcomes and Spinal Cord Stimulation: A Retrospective Case Series Evaluating Patient Satisfaction, Pain Scores, and Opioid Requirements.

INTRODUCTION: Spinal cord stimulators (SCS) are used to treat various chronic pain states. Establishing patient outcomes in terms of pain control, opioid medication use, and overall satisfaction is vital in maintaining SCS's role in clinical practice. METHODS: All patients who underwent SCS implantation between January 2001 and December 2011 at a tertiary academic pain medicine center were included if he or she underwent permanent cervical or thoracolumbar dorsal column SCS implantation and age was 18 or greater. For the 199 patients who met inclusion criteria, data were collected retrospectively. Preimplant information included indication for implantation, Numeric Rating Scale (NRS) score, and dose in oral morphine equivalents (OME). Postimplant NRS score was recorded at 6 months and 1 year. OME requirement and patient satisfaction were determined at 1 year postimplantation. RESULTS: This data set showed an overall decrease in OME requirements and NRS scores at both 6 months and 1 year. These differences were statistically significant (P < 0.01) compared to preimplantation values. Additionally, 84.27% of patients were satisfied with their implants at 1 year. Patient outcomes were analyzed further in respect to implant indication; groups included failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), angina, and other. For all groups, there were statistically significant (P < 0.01) decreases in NRS scores at 6 months and 1 year. In the FBSS and CRPS groups, statistically significant (P < 0.02) decreases in OME usage existed. CONCLUSION: Retrospective review of patients with spinal cord stimulators revealed OME reduction at 1 year for those patients in the FBSS and CRPS groups; patient satisfaction at 1 year and NRS score reduction at 6 months and 1 year were statistically significant for all groups.

Pain Catastrophizing and Anxiety are Associated With Heat Pain Perception in a Community Sample of Adults With Chronic Pain.

BACKGROUND: The principle aim of this study was to investigate the associations between heat pain (HP) perception, pain catastrophizing, and pain-related anxiety in a heterogenous cohort of community-dwelling adults with chronic pain admitted to a 3-week outpatient pain rehabilitation program. METHODS: All adults consecutively admitted to an outpatient pain rehabilitation program from July 2009 through January 2011 were eligible for study recruitment (n=574). Upon admission, patients completed the Pain Catastrophizing Scale (PCS), the short version of the Pain Anxiety Symptoms Scale (PASS-20), and HP perception was assessed using a standardized quantitative sensory testing (QST) method of levels. RESULTS: Greater PCS scores were significantly correlated with lower standardized values of HP threshold (HP 0.5) (P=0.006) and tolerance (HP 5) (P=0.003). In a multiple variable model adjusted for demographic and clinical factors known to influence HP perception, every 10-point increase in the PCS was associated with a -0.124 point change in HP 0.5 (P=0.014) and a -0.142 change in HP 5 (P=0.014) indicating that participants with higher PCS scores had lower HP thresholds and tolerances, respectively. Similarly, greater PASS-20 scores significantly correlated with lower standardized values of HP 0.5 and HP 5. In a multiple variable model, every 10-point increase in the PASS-20 was associated with a -0.084 point change in HP 0.5 (P=0.005) and a -0.116 point change in HP 5 (P=0.001) indicating that participants with higher PASS-20 scores had lower HP thresholds and tolerances, respectively. CONCLUSIONS: The findings of this study extend the use of a standardized method for assessing HP in a heterogenous sample of adults with chronic pain. Although pain catastrophizing shares significant variance with pain-related anxiety, our findings suggest that either measure would be appropriate for use in future studies that incorporate the QST method of levels.

Pain Management in Four-Limb Amputation: A Case Report.

Acute pain following amputation can be challenging to treat due to multiple underlying mechanisms and variable clinical responses to treatment. Furthermore, poorly controlled preoperative pain is a risk factor for developing chronic pain. Evidence suggests that epidural analgesia and peripheral nerve blockade may decrease the severity of residual limb pain and the prevalence of phantom pain after lower extremity amputation. We present the perioperative analgesic management of a patient with gangrene of the bilateral upper and lower extremities as a result of septic shock and prolonged vasopressor administration who underwent four-limb amputation in a single procedure. A multimodal analgesic regimen was utilized, including titration of preoperative opioid and neuropathic pain agents, perioperative intravenous, epidural and peripheral nerve catheter infusions, and postoperative oral medication titration. More than 8 months postoperatively, the patient has satisfactory pain control with no evidence for phantom limb pain. To our knowledge, there have been no publications to date concerning analgesic regimens in four-limb amputation.