Electrical (Pain) Thresholds and Conditioned Pain Modulation in Patients with Low Back-Related Leg Pain and Patients with Failed Back Surgery Syndrome: A Cross-Sectional Pilot Study.

OBJECTIVE: When evaluating sensory dysfunctions and pain mechanisms in patients with low back pain (LBP), a specific subgroup of patients with radicular symptoms is often excluded. Comparative studies that evaluate sensory sensitivity in patients with a dominant nociceptive and neuropathic pain component are rarely performed. Therefore, the goal of this study was to examine differences in electrical thresholds and conditioned pain modulation (CPM) between patients with low back-related leg pain (LBRLP) and patients with failed back surgery syndrome (FBSS). DESIGN: Cross-sectional study. SETTING: University Hospital Brussels. SUBJECTS: Twenty-one patients with LBRLP and 21 patients with FBSS were included. METHODS: Electrical detection thresholds (EDTs), electrical pain thresholds (EPTs), and CPM were evaluated on the symptomatic and nonsymptomatic sides. Within- and between-group differences were evaluated for all parameters. RESULTS: No between-group differences were found for EDT and EPT at both sides. On the nonsymptomatic side, a significantly lower CPM effect was found in the FBSS group (P = 0.04). The only significant within-group difference was an increased EDT at the symptomatic side in patients with FBSS (P = 0.01). CONCLUSIONS: LBP patients with a primary neuropathic pain component revealed altered detection sensitivity at the symptomatic side, without severe indications for altered nociceptive processing, compared with LBP patients without a dominant neuropathic pain component. Endogenous modulation is functioning in LBP patients, although it is possible that it might only be functioning partially in patients with a dominant neuropathic pain component.

Cortical Mapping in Conventional and High Dose Spinal Cord Stimulation: An Exploratory Power Spectrum and Functional Connectivity Analysis With Electroencephalography.

OBJECTIVES: Spinal cord stimulation (SCS) is considered an effective pain-relieving treatment for patients with Failed Back Surgery Syndrome (FBSS). Despite the clinical effectiveness, it is unknown whether the altered functional connectivity in such patients, as compared to healthy persons, can be influenced by SCS. Therefore, the goal of this study is to evaluate whether brain connectivity assessed by EEG differs between baseline and SCS in patients with FBSS. MATERIALS AND METHODS: Eight patients with FBSS underwent a resting-state EEG protocol before SCS, 1.5 months and 2.5 months after receiving SCS. At each frequency band, power spectrums were compared for no SCS, conventional (CON) SCS and High Dose (HD) SCS. Functional connectivity, with the aid of eConnectome was also calculated. RESULTS: Significant differences in the average power density spectrum over the whole scalp were observed between no SCS, CON SCS and HD SCS in delta, theta and beta frequency bands (p < 0.01). The average power spectrum for CON SCS was significantly lower than the average power spectrum for HD SCS. Marked increases in strength of the information flow between electrode pair FC3-TP9 in the beta frequency band (p = 0.006) were found in favor of HD SCS. CONCLUSIONS: The differences in power spectrum and connectivity between the three conditions lead to the hypothesis that HD SCS differs from CON SCS on average power spectrum, suggesting that HD SCS may have a higher contribution on the excitatory bottom-up pathway.

Decreased tibial nerve movement in patients with failed back surgery syndrome and persistent leg pain.

PURPOSE: To measure and compare the total and normalised tibial nerve movements during forward bending in patients with and without failed back surgery syndrome (FBSS) and persistent leg pain following anatomically successful lumbar decompression surgery and demonstrated no psychological stress. Nerve pathomechanics may contribute to FBSS with persistent leg pain following anatomically successful lumbar decompression surgery. METHODS: Tibial nerve movement during forward bending was measured in two groups of patients following anatomically successful lumbar decompression surgery. FBSS group (N = 37) consisted of patients with persistent leg pain following lumbar surgery, and non-FBSS (N = 37) were patients with no remaining leg pain following lumbar surgery. Total and normalised tibial nerve movement at the popliteal fossa was measured by a previously validated ultrasound imaging technique and compared between the two groups, and also between the painful and non-painful leg within the FBSS group. RESULTS: Both the mean total and normalised tibial nerve movement were significantly decreased in the FBSS group in both legs when compared to the non-FBSS group (P < 0.05). The total and normalised tibial nerve movements were also more restricted in the painful leg (P < 0.05) when compared to the non-painful side within the FBSS group. CONCLUSION: This was the first study to quantify the decreased total and normalised tibial nerve mobility in FBSS patients with persistent leg pain when compared with non-FBSS patients following anatomically successful lumbar decompression surgery. Further research could investigate the efficacy of intervention, such as nerve mobilisation in this particular group of patients with failed back surgery syndrome and limited nerve mobility. These slides can be retrieved under Electronic Supplementary Material.

Comparison of Tonic vs. Burst Spinal Cord Stimulation During Trial Period.

BACKGROUND: Spinal cord stimulation (SCS) is a well-known treatment in patients with failed back surgery syndrome (FBSS). Burst stimulation is a recently developed stimulation modality that seems to be superior to tonic stimulation. METHODS: This observational multicenter study compared tonic and burst stimulation during a trial period in patients with FBSS or radiculopathy. All the patients enrolled underwent two weeks of tonic stimulation followed by another two weeks of BurstDR stimulation, without randomization. The primary outcome was the reduction of pain in the legs and back. Health-related quality of life (EQ-5D) and the pain catastrophizing scale (PCS) were assessed before and after the trial. Patients were reevaluated after 12 months. RESULTS: We recruited 23 patients, 57% of whom had FBSS and 43% had radiculopathies. Five patients failed both the tonic and burst stimulation trials. While tonic stimulation reduced leg pain (p < 0.05), the burst mode added an extra pain reduction (ΔNRS 1.2 ± 1.5) (p < 0.01). No significant reduction in back pain was found (p 0.29). Pain on movement was reduced only by BurstDR (p < 0.01). Both stimulation modalities increased EQ-5D and reduced PCS from the baseline (p < 0.0001). At the end of the SCS trial phase, 26% patients chose tonic SCS, while 74% preferred burst. On 12-month follow-up examination, the benefits recorded at the end of the trial were maintained. CONCLUSIONS: Burst stimulation confers a greater reduction in leg pain intensity at rest and on movement. Reducing axial pain is still a challenge. Further studies are needed in order to provide each patient with the most appropriate stimulation paradigm.

Characterizing the Somatosensory Profile of Patients With Failed Back Surgery Syndrome With Unilateral Lumbar Radiculopathy Undergoing Spinal Cord Stimulation: A Single Center Prospective Pilot Study.

OBJECTIVES: Currently little objective evidence exists regarding the phenotype or somato-sensory profile of patients with Failed Back Surgery Syndrome (FBSS). The aim of this study is to characterize the somato-sensory profile of the patients with FBSS undergoing spinal cord stimulation (SCS). METHODS: A combined quantitative sensory test and questionnaire approach was used to characterize the somatosensory profiles of patients undergoing SCS. RESULTS: Baseline somatosensory profiles were obtained from 23 patients and full three-month data was obtained from 19 patients. At baseline, there was a high prevalence (>50% prevalence of moderate to severe sensation) of burning, tingling, electric shock, numbness, and pressure pain sensitivity. None of the sensory symptoms were present at significant levels at three months following SCS. At baseline, 65% of patients had an inefficient conditioned pain modulation (CPM). Three months post-SCS, 95% of patients had an efficient CPM. All the patients who had an inefficient CPM at baseline had a successful implant at three months and their CPM became efficient in all but one patient. Only 50% of the patients with an efficient CPM at baseline, had a successful implant at three months post-SCS. CONCLUSION: Although very low numbers, we could demonstrate the somatosensory profiles of patients with FBSS undergoing SCS. Early indication may associate an efficient CPM profile having a higher chance of an unsuccessful implant at three months.

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.

Analgesic therapy for major spine surgery.

Pain following spine surgery is often difficult to control and can persist. Reduction of this pain requires a multidisciplinary approach that depends on contributions of both surgeons and anesthesiologists. The spine surgeon's role involves limiting manipulation of structures contributing to pain sensation in the spine, which requires an in-depth understanding of the specific anatomic etiologies of pain originating along the spinal axis. Anesthesiologists, on the other hand, must focus on preemptive, multimodal analgesic treatment regimens. In this review, we first discuss anatomic sources of pain within the spine, before delving into a specific literature-supported pain management protocol intended for use with spinal surgery.

What is the evidence that neuropathic pain is present in chronic low back pain and soft tissue syndromes? An evidence-based structured review.

OBJECTIVES: The objectives of this evidence-based review were to review the evidence for whether neuropathic pain (NP) is associated with chronic low back pain (CLBP) and soft tissue syndromes (STS), and review the reported prevalence percentages for NP within these syndromes. METHODS: Of 816 reports, 11 addressed the diagnosis of NP in CLBP and five of NP in STS. Studies were grouped by the method of arrival at an NP diagnosis, e.g., physical examination, type of NP inventory utilized, etc. The reported prevalence of NP was determined by aggregating all the patients in all the studies in each grouping. Similarly, the reported prevalence of NP within CLBP and STS was determined by aggregating all the patients with NP from all the studies in those groups. Each study was independently rated by two raters according to 11 quality criteria generating a quality score. The strength and consistency (SAC) of the evidence represented by each grouping was rated according to Agency for Health Care Policy and Research guidelines. RESULTS: In each grouping, 100% of the studies reported some prevalence of NP (none reported zero prevalence). Aggregated NP prevalence for CLBP was 36.6% (SAC level A [consistent multiple studies]) and for STS 41.1% (SAC level A). There was significant variation in prevalence according to the method utilized to diagnose NP. CONCLUSION: There is consistent evidence by all methods that NP is present in CLBP and STS. Reported prevalence percentages by all methods are substantial. This has significant implications for the treatment of CLBP and STS.

Rehabilitation perspectives of neuromodulation.

Chronic pain is one of the most prevalent and costly health care problems in the United States today. Two conditions, failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS), in particular have been difficult to manage, resulting in increased disability and poorer quality of life measures for patients as well as increased treatments cost for payers. Given the cost of chronic pain management and overall subjectivity of analog pain scores, many payers are emphasizing the importance of functional outcomes as a means of assessing efficacy of treatment. Neuromodulation devices such as spinal cord stimulators are shown to be cost effective and able to improve functional outcomes and quality of life. Specific rehabilitation therapies also demonstrate improved functional outcomes. This article aims to discuss the role of rehabilitation in the patient with a neuromodulatory device. From the available data and our clinical experience, we recommend incorporating rehabilitation after placement of a neuromodulation device in order to optimize functional outcomes.

Predictors of pain relief following spinal cord stimulation in chronic back and leg pain and failed back surgery syndrome: a systematic review and meta-regression analysis.

We sought to assess the extent to which pain relief in chronic back and leg pain (CBLP) following spinal cord stimulation (SCS) is influenced by patient-related factors, including pain location, and technology factors. A number of electronic databases were searched with citation searching of included papers and recent systematic reviews. All study designs were included. The primary outcome was pain relief following SCS, we also sought pain score (pre- and post-SCS). Multiple predictive factors were examined: location of pain, history of back surgery, initial level of pain, litigation/worker's compensation, age, gender, duration of pain, duration of follow-up, publication year, continent of data collection, study design, quality score, method of SCS lead implant, and type of SCS lead. Between-study association in predictive factors and pain relief were assessed by meta-regression. Seventy-four studies (N = 3,025 patients with CBLP) met the inclusion criteria; 63 reported data to allow inclusion in a quantitative analysis. Evidence of substantial statistical heterogeneity (P < 0.0001) in level of pain relief following SCS was noted. The mean level of pain relief across studies was 58% (95% CI: 53% to 64%, random effects) at an average follow-up of 24 months. Multivariable meta-regression analysis showed no predictive patient or technology factors. SCS was effective in reducing pain irrespective of the location of CBLP. This review supports SCS as an effective pain relieving treatment for CBLP with predominant leg pain with or without a prior history of back surgery. Randomized controlled trials need to confirm the effectiveness and cost-effectiveness of SCS in the CLBP population with predominant low back pain.

Spinal cord stimulation modulates cerebral function: an fMRI study.

INTRODUCTION: Although spinal cord stimulation (SCS) is widely used for chronic neuropathic pain after failed spinal surgery, little is known about the underlying physiological mechanisms. This study aims to investigate the neural substrate underlying short-term (30 s) SCS by means of functional magnetic resonance imaging in 20 patients with failed back surgery syndrome (FBSS). METHODS: Twenty patients with FBSS, treated with externalized SCS, participated in a blocked functional magnetic resonance imaging design with stimulation and rest phases of 30 s each, repeated eight times in a row. During scanning, patients rated pain intensity over time using an 11-point numerical rating scale with verbal anchors (0 = no pain at all to 10 = worst pain imaginable) by pushing buttons (left hand, lesser pain; right hand, more pain). This scale was back projected to the patients on a flat screen allowing them to manually direct the pain indicator. To increase the signal-to-noise ratio, the 8-min block measurements were repeated three times. RESULTS: Marked deactivation of the bilateral medial thalamus and its connections to the rostral and caudal cingulate cortex and the insula was found; the study also showed immediate pain relief obtained by short-term SCS correlated negatively with activity in the inferior olivary nucleus, the cerebellum, and the rostral anterior cingulate cortex. CONCLUSIONS: Results indicate the key role of the medial thalamus as a mediator and the involvement of a corticocerebellar network implicating the modulation and regulation of averse and negative affect related to pain. The observation of a deactivation of the ipsilateral antero-medial thalamus might be used as a region of interest for further response SCS studies.

Predictors of surgical, general and follow-up complications in lumbar spinal stenosis relative to patient age as emerged from the Spine Tango Registry.

INTRODUCTION: Published opinions regarding the outcomes and complications in older patients have a broad spectrum and there is a disagreement whether surgery in older patients entails a higher risk. Therefore this study examines the risk of surgery for lumbar spinal stenosis relative to age in the pooled data set of the Spine Tango registry. MATERIALS AND METHODS: Between May 2005 and February 2010 the database query resulted in 1,764 patients. The patients were subdivided into three socio-economically relevant age groups: <65 years, 65-74 years, ≥75 years. Frequencies for occurred surgical, general and follow-up complications were assessed. Multivariate and univariate logistic regressions were performed to reveal predictors for respective complication types. RESULTS AND DISCUSSION: Our study found that age, ASA status and blood loss were significant co-varieties for the occurrence of general complications. The risk of general complications is increased in older versus younger patients. Fusion or rigid stabilization does not lead to more complications. Surgical complications as well as complication rates at follow-up showed no significant age-related variation. Physician-based outcome was good or excellent in over 80% of patients in all age groups.

The Fernstrom ball revisited.

INTRODUCTION: In 1959, Harmon was the first to implant a vitallium sphere into the intervertebral disc space in order to preserve mobility and maintain disc height in patients with back pain secondary to degenerative disc disease. Fernstrom reported good results after implantation of stainless steel spheres. However, a reduction in disc height frequently occurred secondary to sphere subsidence into the endplates. This often led to revision surgery, and the concept was abandoned. MATERIALS AND METHODS: We report on four patients who underwent cobalt-chrome sphere implantation, and later presented to us with symptoms that were a direct result of sphere subsidence. All four patients presented with low back pain and/or lower extremity pain, and some with weakness. Imaging demonstrated that all patients had a loss of disc space height with sphere subsidence. Three patients underwent sphere removal, anterior interbody fusion using femoral ring allograft and posterior pedicle or facet screw fixation. In the fourth patient, the sphere was subsided into both the L5 and S1 endplates prohibiting removal. The patient underwent a posterior L5-S1 posterolateral fusion and facet screw fixation. The length of time from sphere implantation to the revision surgery ranges from 8 to 41 months. RESULTS: Ten months to 3 years after the revision surgery, all four patients reported an improvement in outcome. CONCLUSION: To the best of our knowledge, this is the first report describing the complications resulting from cobalt chrome sphere implantation and revision strategies for managing the recently resurrected cobalt chrome sphere.

[Epidural spinal cord stimulation for therapy of chronic pain. Summary of the S3 guidelines]. / Epidurale Rückenmarkstimulation zur Therapie chronischer Schmerzen. Zusammenfassung der S3-Leitlinie.

Epidural spinal cord stimulation (SCS) is a reversible but invasive procedure which should be used for neuropathic pain, e.g. complex regional pain syndrome I (CRPS) and for mostly chronic radiculopathy in connection with failed back surgery syndrome following unsuccessful conservative therapy. Epidural SCS can also successfully be used after exclusion of curative procedures and conservative therapy attempts for vascular-linked pain, such as in peripheral arterial occlusive disease stages II and III according to Fontaine and refractory angina pectoris. Clinical practice has shown which clinical symptoms cannot be successfully treated by epidural SCS, e.g. pain in complete paraplegia syndrome or atrophy/injury of the sensory pathways of the spinal cord or cancer pain. A decisive factor is a critical patient selection as well as the diagnosis. Epidural SCS should always be used within an interdisciplinary multimodal therapy concept. Implementation should only be carried out in experienced therapy centers which are in a position to deal with potential complications.

Relationship between health-related quality of life, pain, and functional disability in neuropathic pain patients with failed back surgery syndrome.

OBJECTIVES: Patients with failed back surgery syndrome (FBSS) and chronic neuropathic pain experience levels of health-related quality of life (HRQoL) that are considerably lower than those reported in other areas of chronic pain. The aim of this article was to quantify the extent to which reductions in (leg and back) pain and disability over time translate into improvements in generic HRQoL as measured by the EuroQoL-5D and SF-36 instruments. METHODS: Using data from the multinational Prospective, Randomized, Controlled, Multicenter Study of Patients with Failed Back Surgery Syndrome trial, we explore the relationship between generic HRQoL--assessed using two instruments often used in clinical trials (i.e., the SF-36 and EuroQol-5D)--and disease-specific outcome measures (i.e., Oswestry disability index [ODI], leg and back pain visual analog scale [VAS]) in neuropathic patients with FBSS. RESULTS: In our sample of 100 FBSS patients, generic HRQoL was moderately associated with ODI (correlation coefficient: -0.462 to -0.638) and mildly associated with leg pain VAS (correlation coefficient: -0.165 to -0.436). The multilevel regression analysis results indicate that functional ability (as measured by the ODI) is significantly associated with HRQoL, regardless of the generic HRQoL instrument used. On the other hand, changes over time in leg pain were significantly associated with changes in the EuroQoL-5D and physical component summary scores, but not with the mental component summary score. CONCLUSIONS: Reduction in leg pain and functional disability is statistically significantly associated with improvements in generic HRQoL. This is the first study to investigate the longitudinal relationship between generic and disease-specific HRQoL of neuropathic pain patients with FBSS, using multinational data.

Incidence and severity of epidural fibrosis after back surgery: an endoscopic study.

BACKGROUND: Epidural fibrosis has been implicated in the etiology of persistent pain after back surgery (Failed Back Surgery Syndrome [FBSS]). Using spinal endoscopy to view the lumbosacral epidural cavity, the incidence, severity, and appearance of epidural fibrosis was evaluated in patients with FBSS. METHODS: A prospective cohort observational study using epidural endoscopy was done involving 78 patients with persistent pain after back surgery. Patients were evaluated prospectively for the presence of epidural fibrosis and fibrosis was rated using a 4-level grading system based on appearance and resistance to epiduroscope advancement. The incidence of fibrosis detected by epiduroscopy vs. the incidence as reported in magnetic resonance imaging (MRI) studies for the same patients were compared. RESULTS: As diagnosed with epiduroscopy, 83.3% of all patients with persistent pain after back surgery had severe (grade 3 or 4) epidural fibrosis, while 91.0% had significant (grade 2, 3, or 4) fibrosis. In patients who had undergone more extensive surgery, severe fibrosis was present in 91.1% and significant fibrosis in 95.6%. Using MRI, epidural fibrosis was diagnosed only in 16.1% of these patients. All patients with severe epidural fibrosis had a filling defect on epidurography. Concordant pain was present in 84.3% of patients and depended on the severity of fibrosis. Results were statistically evaluated using analysis of frequencies and t-test. P < 0.05 was considered statistically significant. CONCLUSIONS: Epiduroscopy demonstrates that the prevalence of severe epidural fibrosis after FBSS is substantially higher than is generally reported in MRI evaluations. Severe epidural fibrosis is an underlying pathology in most patients with FBSS.

Views of patients suffering from Failed Back Surgery Syndrome on their health and their ability to adapt to daily life and self-management: A qualitative exploration.

BACKGROUND: The clinical outcomes of Spinal Cord Stimulation (SCS) therapy in patients with a Failed Back Surgery Syndrome (FBSS) is mostly done by standardized pain and quality of life measurements instruments and hardly account for personal feelings and needs as a basis for a patient-centred approach and shared decision making. OBJECTIVES: The objective of this study is to explore perspectives on personal health and quality of life (QoL) in FBSS patients concerning their physical-, psychological and spiritual well-being prior to receiving an SCS system. METHODS: We performed face-to-face, semi-structured, in-depth interviews to obtain descriptive and detailed data on personal health, guided by the Web diagram of Positive Health (Huber et al.) and a topic list. The following main topics were assessed qualitatively: 1) Bodily functioning, 2) Mental function and perception 3) Spiritual dimension, 4) Quality of life, 5) Social and societal participation and 6) Daily functioning. RESULTS: Seventeen FBSS patients (eight male, nine female) were included from April-November 2019 at the department of pain medicine in the Albert Schweitzer Hospital in the Netherlands. Median age 49 years; range 28 to 67 years, and patients underwent between one and five lumbar surgical operations. The duration of their chronic pain was between four and 22 years. After analyzing the interviews, three themes emerged: 1) dealing with chronic pain, 2) the current situation regarding aspects of positive health, and 3) future perspectives on health and quality of life. These themes arose from eleven categories and a hundred ninety codes. CONCLUSION: This qualitative study explored FBSS patients 'views on their health and the ability to adapt to daily life having complex chronic pain, and showed that patients experienced shortcomings in daily life within the six dimensions of the Web diagram of Positive Health before the SCS implant.

Long-Term Multicolumn-Lead Spinal Cord Stimulation Efficacy in Patients with Failed Back Surgery Syndrome: A Six-Year Prospective Follow-up Study.

OBJECTIVE: The use of multicolumn-lead spinal cord stimulation (SCS) to control back pain (BP) and leg pain (LP) in patients with failed back surgery syndrome (FBSS) in the short term and mid-term has been well documented. Our study investigated whether SCS remained efficient after 72 months. METHODS: In an observational, single-center study, we assessed SCS efficacy in 62 patients with FBSS patients. BP, LP, and magnitude of daily activity limitation (DAL) were graded using a 0-10 visual analog scale (VAS) preoperatively and at 2, 6, 12, 24, 36, and 72 months after SCS implantation. Sleep quality, use of medications, and complications were also recorded. RESULTS: Of the 62 patients, 15 with complete follow-up data available were still using their SCS device at 72 months (SCS+). For these patients, the VAS scores for BP, LP, and DAL had changed from a median of 9 (interquartile range [IQR], 8.5-10), 7 (IQR, 6-8), and 8 (IQR, 8-9) preoperatively to a median of 4 (IQR, 3-4.5), 3 (IQR, 1.5-3.5), and 3 (IQR, 2-4) at 72 months. Their quality of sleep and analgesic medication consumption had also improved. In a subset of patients no longer using the SCS device after 72 months (SCS-), the VAS scores for BP, LP, and DAL, quality of sleep, and medication consumption were comparable to those for the SCS+ group. The SCS- group was less satisfied with the technique and were less professionally active than were the SCS+ group. CONCLUSIONS: The SCS device provides sustained beneficial effects on BP, LP, DAL, sleep, and medication consumption in patients with FBSS still using it at 72 months postoperatively. Further studies are needed to identify the factors of adherence to the technique and the chances of success compared with the natural evolution of FBSS.

Effects of spinal cord stimulation on voxel-based brain morphometry in patients with failed back surgery syndrome.

OBJECTIVE: Despite the clinical effectiveness of Spinal Cord Stimulation (SCS), potential structural brain modifications have not been explored. Our aim was to identify structural volumetric changes during subsensory SCS, in patients with Failed Back Surgery Syndrome (FBSS). METHODS: In this cohort study, twenty-two FBSS patients underwent a magnetic resonance imaging protocol before SCS and 3 months after SCS. Clinical parameters were correlated with volumetric changes, calculated with voxel-based morphometry. RESULTS: After 3 months, a significant volume decrease was found in the inferior frontal gyrus, precuneus, cerebellar posterior lobe and middle temporal gyrus. Significant increases were found in the inferior temporal gyrus, precentral gyrus and the middle frontal gyrus after SCS. Additionally, significant increases in volume of superior frontal and parietal white matter and a significant decrease in volume of white matter underlying the premotor/middle frontal gyrus were revealed after SCS. A significant correlation was highlighted between white matter volume underlying premotor/middle frontal gyrus and leg pain relief. CONCLUSIONS: This study revealed for the first time that SCS is able to induce volumetric changes in gray and white matter, suggesting the reversibility of brain alterations after chronic pain treatment. SIGNIFICANCE: Volumetric brain alterations are observable after 3 months of subsensory SCS in FBSS patients.

Does ultrasound-guided facet joint injection reduce pain and improve mobility in patients with failed back surgery syndrome?

OBJECTIVES: This study aims to evaluate whether ultrasound (US)-guided facet joint injection reduces pain and improves mobility in patients with failed back surgery syndrome (FBSS). PATIENTS AND METHODS: This retrospective study included 27 patients (8 males, 19 females; mean age 43.6±11.5 years; range, 31 to 54 years) who underwent US-guided facet injections for FBSS between January 2017 and January 2019. Patients' medial records were assessed. Pain rating scores were evaluated with the Numeric Rating Scale (NRS). Functional status was assessed with Oswestry Disability Index (ODI) version 2.0. Lumbar flexion degree was noted. After injection (lidocaine-betamethasone mixture), patients were reevaluated at first and sixth months. The study data were analyzed with Wilcoxon signed-rank test. RESULTS: Successful facet joint injections were achieved without any complications in all patients. The median duration of time after surgery was 7.8±1.3 months. Mean duration of pain was 6.7±5.7 months. There was a significant decrease in NRS values between baseline and sixth month comparison (7.0 at baseline and 6.0 at sixth month, p=0.006). Baseline-first month and first-sixth months comparisons were not significant (p=0.165 and p=0.106, respectively). For ODI, no significant change was observed between baseline-first month, first-sixth months, and baseline-sixth month comparisons (p=0.109, p=0.857, and p=0.095, respectively). For lumbar flexion, all comparisons resulted in significant increase (50.0° for baseline, 60.0° at first month, and 70.0° at sixth month; p<0.001 for baseline-first month comparison, p<0.001 for baseline-sixth month comparison, and p<0.001 for first-sixth months comparison). CONCLUSION: Our results show that pain is reduced and mobility is improved with US-guided facet joint injections in patients with FBSS.