Effect of spinal cord stimulation on quality of life and opioid consumption in patients with failed back surgery syndrome.

BACKGROUND: Failed back surgery syndrome (FBSS) is a constellation of conditions occurring after spine surgeries, characterized by the presence of persistent or recurring low back pain that has a significant impact on patients' quality of life. Neuromodulation in the form of Spinal Cord Stimulation (SCS) is considered an indispensable treatment modality in the management of certain chronic pain conditions and it is showing good results for improvement in pain scores and functional capacity of the FBSS patients. OBJECTIVES: To assess the change in pain scores, quality of life, and opioid medication intake as an outcome of neuromodulation procedures performed on patients diagnosed with failed back surgery syndrome, and to detect the post-procedure complications. METHODS: A prospective observational study was conducted at two university hospitals in Egypt and the U.S.A. during the period from September 2019 to August 2021 for patients who underwent spinal cord stimulation procedures for FBSS with follow-up period of at least 1 year. Patients who are 18 years old or older diagnosed with FBSS for more than 6 months and treated with spinal cord stimulation with successful trials during this time frame were included in the study. RESULTS: Thirty-four patients were included in this study who had successful SCS trials and underwent permanent implantation of SCS devices with post-procedure follow-up period of 12 months. Patients showed a median pain numerical rating scale (NRS) of 7/10 at baseline with a median NRS of 4/10 through the follow-up period. Basic mobility and daily activity scores assessed by activity measure of post-acute care (AM-PAC) showed significant improvement from the mean of 16.87 ± 2.74 at baseline to a mean of 19.97 ± 2.93 through follow-up. In addition, there was a reduction in opioid medication usage. Post-procedure complications was of low percentage with the most detected were battery dysfunction in 7 patients and pocket pain in 6 patients. Reoperation was needed in 13 patients with 4 needed just revision and 9 patients required a complete removal of the device. CONCLUSION: Spinal cord stimulation is an effective modality of treatment for cases of failed back surgery syndrome with a statistically significant reduction in pain scores and a significant improvement in quality of life. Also, it achieves a recognizable reduction in opioid analgesic medications, with a reliable safety profile as detected with the recorded post-procedure complications. However, randomized controlled trials with more patients and long-term follow-up are highly recommended.

Neuromodulation for chronic pain.

Neuromodulation is an expanding area of pain medicine that incorporates an array of non-invasive, minimally invasive, and surgical electrical therapies. In this Series paper, we focus on spinal cord stimulation (SCS) therapies discussed within the framework of other invasive, minimally invasive, and non-invasive neuromodulation therapies. These therapies include deep brain and motor cortex stimulation, peripheral nerve stimulation, and the non-invasive treatments of repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and transcutaneous electrical nerve stimulation. SCS methods with electrical variables that differ from traditional SCS have been approved. Although methods devoid of paraesthesias (eg, high frequency) should theoretically allow for placebo-controlled trials, few have been done. There is low-to-moderate quality evidence that SCS is superior to reoperation or conventional medical management for failed back surgery syndrome, and conflicting evidence as to the superiority of traditional SCS over sham stimulation or between different SCS modalities. Peripheral nerve stimulation technologies have also undergone rapid development and become less invasive, including many that are placed percutaneously. There is low-to-moderate quality evidence that peripheral nerve stimulation is effective for neuropathic pain in an extremity, low quality evidence that it is effective for back pain with or without leg pain, and conflicting evidence that it can prevent migraines. In the USA and many areas in Europe, deep brain and motor cortex stimulation are not approved for chronic pain, but are used off-label for refractory cases. Overall, there is mixed evidence supporting brain stimulation, with most sham-controlled trials yielding negative findings. Regarding non-invasive modalities, there is moderate quality evidence that repetitive transcranial magnetic stimulation does not provide meaningful benefit for chronic pain in general, but conflicting evidence regarding pain relief for neuropathic pain and headaches. For transcranial direct current stimulation, there is low-quality evidence supporting its benefit for chronic pain, but conflicting evidence regarding a small treatment effect for neuropathic pain and headaches. For transcutaneous electrical nerve stimulation, there is low-quality evidence that it is superior to sham or no treatment for neuropathic pain, but conflicting evidence for non-neuropathic pain. Future research should focus on better evaluating the short-term and long-term effectiveness of all neuromodulation modalities and whether they decrease health-care use, and on refining selection criteria and treatment variables.

Efficacy of Minimally Invasive Trans-Sacral Canal Plasty between Patients with and without Failed Back Surgery Syndrome.

Background and Objectives: Clinicians are required to manage a growing number of elderly patients with several medical comorbidities, and invasive surgical treatments are sometimes not advisable for these patients. The aim of this study was to evaluate the efficacy of minimally invasive intraspinal canal treatment, trans-sacral canal plasty (TSCP), for patients with and without failed back surgery syndrome (FBSS). Materials and Methods: A multicenter analysis was conducted. TSCP was performed in patients with chronic low back pain and leg pain due to lumbar spinal disorders. An adhesiolysis by TSCP was carried out, then a mixture of steroid and local anesthesia was injected. Visual Analog Scales (VAS) for low back pain and leg pain, and complications were evaluated. Results: A total of 271 patients with a minimum 6-month follow-up were enrolled. There were 80 patients who had a history of previous lumbar spinal surgery (F group), and 191 patients without previous lumbar spinal surgery (N group). There were no significant differences in sex and age between the two groups. VAS scores for low back pain (N group/F group) preoperatively, immediately postoperatively, and 1 month, 3 months and 6 months postoperatively, were 51/52 mm, 24/26 mm, 33/34 mm, 30/36 mm, and 30/36 mm, respectively. VAS scores for leg pain were 69/67 mm, 28/27 mm, 39/41 mm, 36/43 mm, and 32/40 mm, respectively. Both VAS scores for low back pain and leg pain were significantly decreased from baseline to final follow-up in both groups (p < 0.01). However, VAS scores for leg pain at 3 months and 6 months postoperatively were significantly higher in F group (p < 0.05). There were three catheter breakages (2/3 in F group), and one dural tear in F group. Conclusions: TSCP significantly reduced both VAS scores for low back and leg pain in patients with and without FBSS. However, co-existence of intractable epidural adhesion might be associated with less improvement in FBSS.

Socioeconomic Disparities in the Utilization of Spinal Cord Stimulation Therapy in Patients with Chronic Pain.

OBJECTIVES: Spinal cord stimulation (SCS) therapies are used in the management of patients with complex regional pain syndrome I (CRPS I) and failed back surgery syndrome (FBSS). The purpose of this study was to investigate the racial and health insurance inequalities with SCS therapy in patients with chronic pain who had CRPS I and FBSS. METHODS: Patients with chronic pain who had a discharge diagnosis of FBSS and CRPS I were identified using the National Inpatient Sample database. Our primary outcome was defined as the history of SCS utilization by race/ethnicity, income quartile, and insurance status. Multivariable logistic regression was used to determine the variables associated with utilization of SCS therapy. RESULTS: Between 2011 and 2015, 40,858 patients who were hospitalized with a primary diagnosis of FBSS and/or CRPS I were identified. Of these patients, 1,082 (2.7%) had a history of SCS therapy. Multivariable regression analysis revealed that compared to White patients, Black and Hispanic patients had higher odds of having SCS therapy (Black patients: odds ratio [OR] = 1.41; 95% confidence interval [CI], 1.12 to 1.77; P = 0.003; Hispanic patients: OR = 1.41; 95% CI, 1.10 to 1.81; P = 0.007). Patients with private insurance had significantly higher odds of having SCS therapy compared with those with Medicare (OR = 1.24; 95% CI, 1.08 to 1.43; P = 0.003). Compared to patients with Medicare, Medicaid patients had lower odds of having SCS therapy (OR = 0.50; 95% CI, 0.36 to 0.70; P < 0.001). CONCLUSIONS: Our study suggests that socioeconomic disparities may exist in the utilization of SCS among hospitalized patients with CRPS I and FBSS the United States. However, confirming these data from other administrative databases, in the outpatient setting, may shed more insight.

A Regions of Interest Voxel-Based Morphometry Study of the Human Brain During High-Frequency Spinal Cord Stimulation in Patients With Failed Back Surgery Syndrome.

INTRODUCTION: The effectiveness of spinal cord stimulation (SCS) as pain-relieving treatment for failed back surgery syndrome (FBSS) has already been demonstrated. However, potential structural and functional brain alterations resulting from subsensory SCS are less clear. The aim of this study was to test structural volumetric changes in a priori chosen regions of interest related to chronic pain after 1 month and 3 months of high-frequency SCS in patients with FBSS. METHODS: Eleven patients with FBSS who were scheduled for SCS device implantation were included in this study. All patients underwent a magnetic resonance imaging protocol before SCS device implantation 1 and 3 months after high-frequency SCS. Pain intensity, pain catastrophizing, and sleep quality were also measured. Regions-of-interest voxel-based morphometry was used to explore grey matter volumetric changes over time. Additionally, volumetric changes were correlated with changes in pain intensity, catastrophizing, and sleep quality. RESULTS: Significant decreases were found in volume in the left and right hippocampus over time. More specifically, a significant difference was revealed between volumes before SCS implantation and after 3 months of SCS. Repeated-measures correlations revealed a significant positive correlation between volumetric changes in the left hippocampus and changes in back pain score over time and between volumetric changes in the right hippocampus and changes in back pain score over time. CONCLUSION: In patients with FBSS, high-frequency SCS influences structural brain regions over time. The volume of the hippocampus was decreased bilaterally after 3 months of high-frequency SCS with a positive correlation with back pain intensity.

Spinal cord stimulation in a patient with multiple sclerosis and failed back surgery syndrome.

In the present article, we described a case of treating intractable pain from failed back surgery syndrome (FBSS) and multiple sclerosis (MS) after implantation of spinal cord stimulation (SCS) in a patient. We are reporting a case where SCS has been used for treating a patient with both FBSS and MS.

[The effect of various multimodal analgesia regimens during surgical treatment of patients with spinal stenosis on the rate of failed back surgery syndrome]. / Vliianie razlichnykh mul'timodal'nykh skhem analgezii pri khirurgicheskom lechenii patsientov so stenozom pozvonochnogo kanala na chastotu sindroma neudachnoi operatsii na pozvonochnike.

OBJECTIVE: To determine the effect of various methods of perioperative analgesia on the rate of failed back surgery syndrome in patients operated on for spinal stenosis. MATERIAL AND METHODS: A total of 122 patients were operated on for spinal stenosis in 2010-2016. The patients were assigned to groups according to the type of received analgesia: Group K (n=19) underwent analgesia on-demand. Patients in the PMA group (n=21) received preventive multimodal analgesia (PMA) with ketoprofen, paracetamol and morphine. Patients in the PMA+PG (n=20) and PMA+N (n=20) groups additionally received pregabalin and nefopam, respectively. Patients in the PMA+E group (n=22) received continuous epidural analgesia with a combination of ropivacaine and morphine. In patients in the PMA+I group (n=20), the wound was infiltrated with ropivacaine and ketorolac. RESULTS AND CONCLUSION: In Group K, analgesia was not adequate during five postoperative days. Analgesia with PMA resulted in significant pain reduction during three postoperative days compared to Group K. Wound infiltration in addition to PMA was followed by more significant pain relief during six postoperative hours (compared to the PMA group). Administration of pregabalin or nefopam, as well as epidural analgesia, did not improve quality of postoperative analgesia. Five to seven months after the surgery, 66% (57; 75%) of patients had low back and/or leg pain; 41% (32; 50%) of patients had leg pain. Among patients suffering from pain, 32-41% patients had the severe chronic pain syndrome that resulted in sleep disorder, disability and significant deterioration of quality of life. The rate of failed back surgery syndrome did not depend on the perioperative analgesia regimen.

Clinical insomnia and associated factors in failed back surgery syndrome: a retrospective cross-sectional study.

Background Insomnia frequently occurs to patients with persistent back pain. By worsening pain, mood, and physical functioning, insomnia could lead to the negative clinical consequences of patients with failed back surgery syndrome (FBSS). This retrospective and cross-sectional study aims to identify the risk factors associated with clinical insomnia in FBSS patients. Methods A total of 194 patients with FBSS, who met the study inclusion criteria, were included in this analysis. The Insomnia Severity Index (ISI) was utilized to ascertain the presence of clinical insomnia (ISI score ≥ 15). Logistic regression analysis evaluates patient demographic factors, clinical factors including prior surgical factors, and psychological factors to identify the risk factors of clinical insomnia in FBSS patients. Results After the persistent pain following lumbar spine surgery worsened, 63.4% of patients reported a change from mild to severe insomnia. In addition, 26.2% of patients met the criteria for clinically significant insomnia. In a multivariate logistic regression analysis, high pain intensity (odds ratio (OR) =2.742, 95% confidence interval (CI): 1.022 - 7.353, P=0.045), high pain catastrophizing (OR=4.185, 95% CI: 1.697 - 10.324, P=0.002), greater level of depression (OR =3.330, 95% CI: 1.127 - 9.837, P=0.030) were significantly associated with clinical insomnia. However, patient demographic factors and clinical factors including prior surgical factors were not significantly associated with clinical insomnia. Conclusions Insomnia should be addressed as a critical part of pain management in FBSS patients with these risk factors, especially in patients with high pain catastrophizing.

Preventive Analgesia with Pregabalin in Neuropathic Pain from "Failed Back Surgery Syndrome": Assessment of Sleep Quality and Disability.

OBJECTIVE: Pregabalin group (PGB) is an antiepileptic used to treat neuropathic pain. We evaluated analgesic efficacy and safety for postoperative/chronic pain, disability, and sleep quality in patients who underwent spine surgery administered with PGB, or not, during the presurgical and postsurgical periods. DESIGN: Retrospective cohort study of 60 patients (two groups with 30 patients) with full information on 50 (29 with PGB and 21 without PGB). Ten patients were dismissed as information was lacking. The PGB group (P) (29 patients) received 75 mg/12 hours before surgery, 150 mg 10 hours after surgery, and 150 mg/12 hours 3 days after surgery. The control group (C; 21 patients) took no PGB. METHODS: Neuropathic pain was assessed before surgery, and 2 and 6 months later using visual analog scales (VAS), DN4, disability (Oswestry), and sleep quality. No serious adverse events occurred with PGB. RESULTS: The median VAS pain score at rest was lower in the PGB group at 2 months postsurgery (1 vs 2, P = 0.032), as was the median DN4 score (0 vs 3, P = 0.032) and the median Oswestry disability index (ODI: 12 vs 18, P = 0.001). At 6 months postsurgery, pain scores were also lower in the PGB group for VAS (0 vs 4, P = 0.001), DN4 score (0 vs 4, P = 0.001) and the ODI (10 vs 24, P = 0.001). Improvement in the functionality and sleep quality of the PGB group was noteworthy (P = 0.018). CONCLUSIONS: PGB has analgesic/antihyperalgesic effects on postoperative neuropathic pain after surgery for lumbar disc hernia. Our findings show that this benefit increases with time.

High Frequency (10 kHz) or Burst Spinal Cord Stimulation in Failed Back Surgery Syndrome Patients With Predominant Back Pain: Preliminary Data From a Prospective Observational Study.

BACKGROUND: Conventional spinal cord stimulation (SCS) exhibits pain relief and improved quality of life in refractory failed back surgery syndrome. However, patients suffering from predominant back pain failed to achieve a favorable neuromodulation outcome. Currently, two new stimulation concepts, the burst and the HF10 stimulation paradigms successfully suppress intractable back pain levels in this difficult-to-treat subgroup. To date, literature data comparing both stimulation patterns is lacking. METHODS: A prospective, observational study was conducted including 16 refractory Failed-back surgery syndrome (FBSS) patients with previous spine surgery and predominant back pain (70% of overall pain) with or without leg pain eligible for burst or high-frequency SCS. At baseline and at a three-month follow-up the pain intensity (back pain (VASB )/leg pain (VASL ), sleep quality (Pittsburgh Sleep Quality Index [PSQI]), changes in severity of depressive symptoms (Beck Depression Inventory [BDI]) and any adverse event related to the implantation and the stimulation were recorded. RESULTS: Overall baseline VASB was significantly suppressed in 14 FBSS patients (eight burst/six patients with 10 HF10) from baseline 7.9 ± 0.7 to 2.3 ± 1 (p < 0.001), while the overall VASL declined significantly from 3.1 ± 1.5 to 1.9 ± 0.83 (p < 0.01). The burst patients experienced significant VASL reduction (burst 1.8 ± 0.7 (p < 0.009) compared to HF10 patients 2.2 ± 1). Two patients failed 10 HF10-trial. The BDI [23.3 ± 2.1 to 13.5 ± 4.5 (p < 0.001)] and the PSQI [7.6 ± 3.7 to 4.2 ± 1.4 (p < 0.003)] dropped down significantly for both modalities. No implantation/stimulation-related complications were observed. CONCLUSIONS: Burst and HF10 SCS performed efficiently and safely in intractable FBSS patients with predominant back pain and deserve more refined, specific investigations to determine their efficacy.

Clinical Outcomes of 1 kHz Subperception Spinal Cord Stimulation in Implanted Patients With Failed Paresthesia-Based Stimulation: Results of a Prospective Randomized Controlled Trial.

BACKGROUND: Pain relief via spinal cord stimulation (SCS) has historically revolved around producing paresthesia to replace pain, with success measured by the extent of paresthesia-pain overlap. In a recent murine study, by Shechter et al., showed the superior efficacy of high frequency SCS (1 kHz and 10 kHz) at inhibiting the effects of mechanical hypersensitivity compared to sham or 50 Hz stimulation. In the same study, authors report there were no differences in efficacy between 1 kHz and 10 kHz delivered at subperception stimulation strength (80% of motor threshold). Therefore, we designed a randomized, 2 × 2 crossover study of low frequency supra-perception SCS vs. subperception SCS at 1 kHz frequency in order to test whether subperception stimulation at 1 kHz was sufficient to provide effective pain relief in human subjects. METHODS: Twenty-two subjects with SCS, and inadequate pain relief based on numeric pain rating scale (NPRS) scores (>5) were enrolled, and observed for total of seven weeks (three weeks of treatment, one week wash off, and another three weeks of treatment). Subjects were asked to rate their pain on NPRS as a primary efficacy variable, and complete the Oswestry Disability Index (ODI) and Patient's Global Impression of Change (PGIC) as secondary outcome measures. RESULTS: Out of 22 subjects that completed the study, 21 subjects (95%) reported improvements in average, best, and worst pain NPRS scores. All NPRS scores were significantly lower with subperception stimulation compared to paresthesia-based stimulation (p < 0.01, p < 0.05, and p < 0.05, respectively). As with NPRS scores, the treatment effect of subperception stimulation was significantly greater than that of paresthesia based stimulation on ODI scores (p = 3.9737 × 10-5 ) and PGIC scores (p = 3.0396 × 10-5 ).

Subcutaneous Stimulation as an Additional Therapy to Spinal Cord Stimulation for the Treatment of Low Back Pain and Leg Pain in Failed Back Surgery Syndrome: Four-Year Follow-Up.

OBJECTIVE: The objective of this study is to investigate the efficacy of long-term follow-up of subcutaneous stimulation (SubQ) as an additional therapy for patients with failed back surgery syndrome (FBSS) with chronic refractory pain, for whom spinal cord stimulation (SCS) alone was unsuccessful in treating low back pain. STUDY DESIGN: Prospective case series. MATERIALS AND METHODS: FBSS patients with leg and/or low back pain whose conventional therapies had failed, received a combination of SCS (8-contact Octad lead, 3877-45 cm, Medtronic, Minneapolis, MN, USA) and/or SubQ (4-contact Quad Plus lead (s), 2888-28 cm, Medtronic). Initially, an Octad lead was placed in the epidural space for SCS for a trial stimulation to assess the suppression of leg and/or low back pain. Where SCS alone was insufficient in treating low back pain, lead(s) were placed superficially in the subcutaneous tissue of the lower back, exactly in the middle of the pain area. A pulse generator (Prime Advanced, 37702, Medtronic) was implanted if the patient reported more than 50% pain relief during the trial period. We investigated the long-term effect of neuromodulation on pain with the visual analog scale (VAS), and disability using the Quebec Pain Disability Scale. The results after 46 months are presented. RESULTS: Eleven patients, five men and six women (age 51 ± 8 years, mean ± SD) were included in the pilot study. In nine cases, SCS was used in combination with SubQ leads. Two patients received only SubQ leads. In one patient, the SCS + SubQ system was removed after nine months and these results were not taken into account for the analysis. Baseline scores for leg (N = 8) and low back pain (N = 10) were VASbl: 59 ± 15 and VASbl: 63 ± 14, respectively. The long-term follow-up period was 46 ± 4 months. SCS significantly reduced leg pain after 12 months (VAS12: 20 ± 11, p12 = 0.001) and 46 months (VAS46: 37 ± 17, p46 = 0.027). Similarly, SubQ significantly reduced back pain after 12 months(VAS12: 33 ± 16, p12 = 0.001) and 46 months (VAS46: 40 ± 21, p46 = 0.013). At 12 months, the Quebec Pain Disability Scale (QPDS) was 49 ± 12 and after 46 months, 53 ± 15. Both at 12 and 46 months, the QPDS values were statistically significantly better (p12 = 0.001, p46 = 0.04) compared with baseline values (QPDSbl: 61 ± 15). In one patient, the pain suppressive effect of SCS/SubQ had disappeared completely over time and the pain scores returned to prestimulation values. In four, patients back pain scores increased over time due to new issues (SI-joint problems, degenerative spine problems, disc problems, and hip pain) unrelated to FBSS and for which SCS/SubQ was not targeted or a reason for implantation at the start of the pilot study. DISCUSSION: This is the first prospective report on the combined use of SCS and SubQ with a follow-up period of four years. These data show that SCS and/or SubQ provide persistent long-term pain relief for leg and back pain in patients with FBSS. One should also take into account that new back/leg pain problems may evolve over time and increase the pain score which impact overall pain treatment. CONCLUSION: SCS combined with SubQ can be considered an effective long term treatment for low back pain in patients with FBSS for whom SCS alone is insufficient in alleviating their pain symptoms.

Acute rhabdomyolysis in a patient with long-term exposure to intrathecal ziconotide: a case report.

INTRODUCTION: Ziconotide is an intrathecally administered nonopioid analgesic for the treatment of severe chronic pain. Previous reports have noted rhabdomyolysis in patients receiving ziconotide during the initial single-shot trial or due to concurrent medical problems. We present a case of an acute rhabdomyolysis following an intrathecal bolus injection of ziconotide on a patient who had long-term exposure to the drug. CASE REPORT: The patient suffered from chronic neuropathic pain with diagnosis of failed back surgery syndrome and received intrathecal ziconotide for 2 years. Moderate side effects resulting from dose escalation led to a discontinuation of the drug. The pump medication was changed to morphine, which failed to provide adequate analgesia even with dose titration. A single intrathecal bolus of ziconotide, as an adjunctive therapy, resulted in good pain control. Two months later, the patient received a second ziconotide injection. Sixteen hours after the injection, she presented to local emergency center with nausea, vomiting, diarrhea, and myalgia. She had significantly increased CK levels and was admitted for intravenous hydration and close observation. Her serum CK level peaked at 4940 IU/L. The patient was discharged on hospital day 3 with a CK level of 808 IU/L. Her symptoms resolved without renal impairment. DISCUSSION: The clinical scenario described is a case of acute rhabdomyolysis from an intrathecal bolus injection of ziconotide in a patient with prior long-term exposure to the drug. The decrease in CK levels coincided well with the average half-life of ziconotide; however, the rhabdomyolysis may have been potentiated by hypokalemia.

Zygapophysial joint pain in post lumbar surgery syndrome. The efficacy of medial branch blocks and radiofrequency neurotomy.

OBJECTIVE: To investigate the prevalence of zygapophysial joint pain in patients after disc surgery, and to determine the effectiveness of radiofrequency neurotomy for its treatment. DESIGN: Retrospective practice audit. SETTING: Review of charts of all patients who underwent lumbar disc surgery during a time period of 2 years. INTERVENTIONS: Patients with persistent back pain after surgery were tested with repeated medial branch blocks. Those patients who consistently report at least 80% pain relief underwent radiofrequency neurotomy. A successful outcome was defined as at least 50% pain reduction enduring for 6 months. RESULTS: In a population of 479 patients who underwent microsurgical lumbar disc operations, persistent axial back pain occurred in 120, of whom 34 had positive responses to diagnostic blocks and were treated with radiofrequency neurotomy. Twenty patients (58.8%) achieved at least 50% reduction in pain for a minimum of 6 months. CONCLUSIONS: The prevalence of zygapophysial joint pain appears to be 7% in patients with failed back surgery syndrome. Patients with this condition can be treated with a radiofrequency neurotomy with a success rate of 58.8%.

Rates of lumbosacral transforaminal injections interpreted as intravascular: fluoroscopy alone or with digital subtraction.

We investigated the rate of injections interpreted as intravascular during imaging of lumbosacral transforaminal epidural injections, using fluoroscopy alone or with digital subtraction. We evaluated 732 injections performed on 348 patients: 8.1% (59/732) and 10.5% (77/732) of injections were interpreted as intravascular during fluoroscopy and digital subtraction, respectively, p = 0.13. The odds ratio (95% CI) for interpreting injections as intravascular increased for both fluoroscopy and digital subtraction fluoroscopy, with: each year of age, 1.04 (1.01-1.07) and 1.03 (1.00-1.06), p = 0.011 and 0.024, respectively; sacral compared with lumbar injections, 10 (5-19) and 8 (5-15), p < 0.001 for both. The odds ratio for intravascular injection increased with three other variables during digital subtraction fluoroscopy: spinal stenosis, 5.1 (1.5-17.1), p = 0.009; failed back surgery syndrome, 4.3 (1.2-15.8), p = 0.025; compression fracture, 8.0 (1.6-39.4), p = 0.011.

Bolus intrathecal injection of ziconotide (Prialt®) to evaluate the option of continuous administration via an implanted intrathecal drug delivery (ITDD) system: a pilot study.

OBJECTIVES: This study evaluated efficacy and safety of bolus doses of ziconotide (Prialt®, Eisai Limited, Hertfordshire, UK) to assess the option of continuous administration of this drug via an implanted intrathecal drug delivery system. MATERIALS AND METHODS: Twenty adults with severe chronic pain who were under consideration for intrathecal (IT) therapy were enrolled in this open label, nonrandomized, pilot study. Informed consent was obtained. Demographics, medical/pain history, pain scores, and concomitant medications were recorded. A physical examination was performed. Creatine kinase was measured. Initial visual analog scale (VAS), blood pressure, heart rate, and respiratory rate were recorded. All patients received an initial bolus dose of 2.5 mcg ziconotide; the dose in the subsequent visits was modified according to response. Subsequent doses were 2.5 mcg, 1.2 mcg, or 3.75 mcg as per protocol. A good response (≥30% reduction in baseline pain VAS) with no side-effects on two occasions was considered a successful trial. Data were analyzed using a generalized estimating equations model, with pain VAS as the outcome and time (seven time points; preinjection and one to six hours postinjection) as the predictor. RESULTS: Generalized estimating equations analysis of summary measures showed a mean reduction of pain VAS of approximately 25% at the group level; of 11 responders, seven underwent pump implantation procedure, two withdrew because of adverse effects, one refused an implant, and one could not have an implant (lack of funding from the Primary Care Trust). CONCLUSIONS: Our data demonstrated that mean VAS was reduced by approximately 25% at the group level after IT ziconotide bolus. Treatment efficacy did not vary with sex, center, age, or pain etiology. Ziconotide bolus was generally well tolerated. Larger studies are needed to determine if bolus dosing with ziconotide is a good predictor of response to continuous IT ziconotide via an intrathecal drug delivery system.

Cerebrospinal fluid levels of vascular endothelial growth factor correlate with reported pain and are reduced by spinal cord stimulation in patients with failed back surgery syndrome.

OBJECTIVES: Spinal cord stimulation (SCS) is an efficacious therapy for chronic neuropathic pain whose precise mechanism of action is unclear. Mediators produced by glial and immune cells are now believed to modulate neuronal transmission and promote chronic neuropathic pain. We postulated a relationship between cerebrospinal fluid (CSF) concentrations of neuroimmune mediators and SCS. MATERIALS AND METHODS: We measured CSF concentrations of the chemokine, monocyte chemotactic protein-1 (MCP-1), and the growth factors, brain-derived neurotrophic factor (BDNF), and vascular endothelial growth factor (VEGF) and tested for relationships with stimulation parameters and clinical response in nine patients with failed back surgery syndrome (FBSS). RESULTS: Patients with FBSS had higher CSF concentrations of BDNF (p = 0.01) and MCP-1 (p = 0.0001) than matched controls. CSF concentrations of BDNF and VEGF correlated with reported pain (p = 0.04). Five minutes of SCS resulted in a reduction in median VEGF concentrations (p = 0.01). CONCLUSIONS: Patients with FBSS have altered CSF levels of BDNF and MCP-1. CSF VEGF correlates with pain and is reduced by SCS. This may offer novel insights into both the mechanism of action of SCS in FBSS and the variation in clinical response that may be encountered.

Spinal Cord Stimulation for Failed Back Surgery Syndrome: to Trial or Not to Trial?

Spinal cord stimulation (SCS) is a recommended therapy to treat failed back surgery syndrome (FBSS). A trial period is practiced to enhance patient selection. However, its fundamental evidence is limited, especially concerning long-term benefit and therapy safety. We compared the long-term (5.3 ± 4.0 years) clinical outcome and therapy safety of a trialed and nontrialed implantation strategy, including multidimensional variables and pain intensity fluctuations over time. A multicenter cohort analysis was performed in 2 comparable groups of FBSS patients. Regarding eligibility, patients had to be treated with SCS for at least 3 months. While the Trial group comprised patients who underwent an SCS implantation after a successful trial, the No-Trial group encompassed patients who underwent complete implantation within 1 session. The primary outcome measures were pain intensity scores and complications. The Trial and No-Trial groups consisted of 194 and 376 patients (N = 570), respectively. A statistically but not clinically significant difference in pain intensity (P = .003; effect = 0.506 (.172-.839)) was found in favor of the Trial group. No interaction between a time dependency effect and pain intensity was noted. Whereas trialed SCS patients were more likely to cease opioid usage (P = .003; OR = .509 (.326-.792)), patients in the No-Trial group endured fewer infections (P = .006; proportion difference = .43 (.007-.083)). Although the clinical relevance of our findings should be proven in future studies, this long-term real-world data study indicates that patient-centered assessments on whether an SCS trial should be performed have to be investigated. According to the current ambiguous evidence, SCS trials should be considered on a case-by-case basis. PERSPECTIVE: The currently available comparative evidence, together with our results, remains ambiguous on which SCS implantation strategy might be deemed superior. An SCS trial should be considered on a case-by-case basis, for which further investigation of its clinical utility in certain patient populations or character traits is warranted.

Assessment of efficacy of percutaneous epidural neuroplasty for lumbar stenosis and failed back surgery syndrome: effective and safe?

OBJECTIVE: Chronic, refractory low back and lower extremity pain is a common problem. There are many causes for persistent low back pain, including spinal stenosis (SS), disc herniation, facet disease, sacroiliac disease, adjacent segment disease, ligamentous disease, and failed back surgery syndrome (FBSS). FBSS and SS are common and often result in chronic, persistent pain and disability. After the failure of conservative treatments, percutaneous epidural neuroplasty (PEN) is often used in managing low back pain. PATIENTS AND METHODS: We retrospectively analyzed 117 patients who received PEN for FBSS and SS between January 2018 and January 2019. Clinical outcomes were assessed with the visual analogue scale (VAS) score and the Oswestry disability index (ODI). The follow-up period was 6 months. We aimed to evaluate the effectiveness of percutaneous epidural neuroplasty in managing chronic refractory low back and lower extremity pain secondary to FBSS and SS and to compare the differences between outcomes of SS and FBSS groups, before and after PEN. RESULTS: Mean VAS scores were 6.15 ± 1.25 preoperatively, 2.97 ± 1.5 after 1 month, 3.18 ± 1.65 after 3 months, and 3.83 ± 1.64 after 6 months of follow-up. Mean ODI scores were 49.91 ± 13.87 preoperatively, 30.19 ± 12.01 after 1 month, 31.61 ± 12.46 after 3 months, 34.58 ± 12.52 after 6 months of follow-up. CONCLUSIONS: Percutaneous epidural neuroplasty was shown to be a safe and effective treatment in managing refractory back/leg pain following FBSS and SS.