From "mechanical" to "neuropathic" back pain concept in FBSS patients. A systematic review based on factors leading to the chronification of pain (part C)

Should we Oppose or Combine Waveforms for Spinal Cord Stimulation in PSPS-T2 Patients? A Prospective Randomized Crossover Trial (MULTIWAVE Study)

Refractory persistent spinal pain syndrome after surgery (PSPS-T2) can be successfully addressed by spinal cord stimulation (SCS). While conventional stimulation generates paresthesia, recent systems enable the delivery of paresthesia-free stimulation. Studies have claimed non-inferiority/superiority of selected paresthesia-free stimulation compared with paresthesia-based stimulation, but the comparative efficacy between different waveforms still needs to be determined in a given patient. We designed a randomized controlled 3-month crossover trial to compare pain relief of paresthesia-based stimulation versus high frequency versus burst in 28 PSPS-T2 patients implanted with multiwave SCS systems. Our secondary objectives were to determine the efficacy of these 3 waveforms on pain surface, quality of life, functional capacity, psychological distress, and validated composite multidimensional clinical response index to provide holistic comparisons at 3-, 6-, 9-, and 15-month post-randomization. The preferred stimulation modality was documented during the follow-up periods. No difference between the waveforms was observed in this study (P = .08). SCS led to significant pain relief, quality of life improvement, improvement of multidimensional clinical response index, and of all other clinical outcomes at all follow-up visits. Forty-four percent of the patients chose to keep the paresthesia-based stimulation modality after the 15-month follow-up period. By giving the possibility to switch and/or to combine several waveforms, the overall rate of SCS responders further increased with 25%. In this study, high frequency or burst do not appear superior to paresthesia-based stimulation, wherefore paresthesia-based stimulation should still be considered as a valid option. However, combining paresthesia-based stimulation with paresthesia-free stimulation, through personalized multiwave therapy, might significantly improve SCS responses. PERSPECTIVE: This article assesses clinical SCS efficacy on pain relief, by comparing paresthesia-based stimulation and paresthesia-free stimulation (including high frequency and burst) modalities in patient presenting with PSPS-T2. Switching and/or combining waveforms contribute to increasing the global SCS responders rate.

Does lumbar spinal decompression or fusion surgery influence outcome parameters in patients with intrathecal morphine treatment for persistent spinal pain syndrome type 2 (PSPS-T2)

OBJECTIVES

Intrathecal morphine pump (ITMP) infusion therapy is efficient in managing chronic pain refractory to standard treatment. This study evaluates pain relief and improvement of quality of life in chronic pain patients after intrathecal morphine pump implantation for treatment of persistent pain after lumbar spinal fusion surgery and lumbar spinal decompression alone.

METHODS

Forty three chronic pain patients that received an ITMP at our department between 2009 and 2019 were retrospectively analyzed divided into 2 cohorts (lumbar spinal fusion surgery and lumbar spinal decompression alone). Pain intensity was evaluated using the numeric rating scale (NRS), quality of life was assessed by EQ-5D-3L, mental health was assessed by Beck Depression Inventory (BDI-V), and Pain Catastrophizing Scale (PCS). Morphine dosage was assessed over time. Data was collected preoperatively, 6 and 24 months postoperatively. Statistical analysis was performed using Friedman's analysis of variance to evaluate the development of NRS, PCS, BDI and EQ-5D-3L over time and Mann-Whitney-U-test for the differences between these parameters in the different cohorts. A two-sided p-value <0.05 was considered statistically significant.

RESULTS

Median age was 64 years (IQR25-75 56-71 years). NRS, EQ-5D-3L, BDI-V, and PCS showed a significant overall improvement after 6 and 24 months compared to baseline data (p<0.001). No statistically significant differences between patients with lumbar spinal fusion surgery and lumbar spinal decompression alone were seen. Furthermore, no statistically significant differences for age and gender were seen. The initially administered median morphine dosage was significantly higher in the fusion group (3.0 mg/day; IQR25-75 1.5-4.2 mg/day) compared to the decompression-alone group (1.5 mg/day; IQR25-75 1.0-2.6 mg/day); (p=0.027).

CONCLUSIONS

This retrospective study showed that ITMP have a major long-term impact on pain relief, improve the quality of life, psychological distress, as well as pain catastrophizing in patients with chronic pain following lumbar spinal surgery independent of the previous surgical procedure. After ITMP implantation initial median morphine dosage seems to be significantly higher after spinal fusion compared to decompressive surgery alone.

"Neuro-Fiber Mapping": An Original Concept of Spinal Cord Neural Network Spatial Targeting Using Live Electrostimulation Mapping to (Re-)Explore the Conus Medullaris Anatomy

Spinal cord (SC) anatomy is often assimilated to a morphologically encapsulated neural entity, but its functional anatomy remains only partially understood. We hypothesized that it could be possible to re-explore SC neural networks by performing live electrostimulation mapping, based on "super-selective" spinal cord stimulation (SCS), originally designed as a therapeutical tool to address chronic refractory pain. As a starting point, we initiated a systematic SCS lead programming approach using live electrostimulation mapping on a chronic refractory perineal pain patient, previously implanted with multicolumn SCS at the level of the conus medullaris (T12-L1). It appeared possible to (re-)explore the classical anatomy of the conus medullaris using statistical correlations of paresthesia coverage mappings, resulting from 165 different electrical configurations tested. We highlighted that sacral dermatomes were not only located more medially but also deeper than lumbar dermatomes at the level of the conus medullaris, in contrast with classical anatomical descriptions of SC somatotopical organization. As we were finally able to find a morphofunctional description of "Philippe-Gombault's triangle" in 19th-century historical textbooks of neuroanatomy, remarkably matching these conclusions, the concept of "neuro-fiber mapping" was introduced.

Factors Determining Plasticity of Responses to Drugs

The plasticity of responses to drugs is an ever-present confounding factor for all aspects of pharmacology, influencing drug discovery and development, clinical use and the expectations of the patient. As an introduction to this Special Issue of the journal IJMS on pharmacological plasticity, we address the various levels at which plasticity appears and how such variability can be controlled, describing the ways in which drug responses can be affected with examples. The various levels include the molecular structures of drugs and their receptors, expression of genes for drug receptors and enzymes involved in metabolism, plasticity of cells targeted by drugs, tissues and clinical variables affected by whole body processes, changes in geography and the environment, and the influence of time and duration of changes. The article provides a rarely considered bird’s eye view of the problem and is intended to emphasize the need for increased awareness of pharmacological plasticity and to encourage further debate.

The Added Value of Subcutaneous Peripheral Nerve Field Stimulation Combined with SCS, as Salvage Therapy, for Refractory Low Back Pain Component in Persistent Spinal Pain Syndrome Implanted Patients: A Randomized Controlled Study (CUMPNS Study) Based on 3D-Mapping Composite Pain Assessment

While Spinal Cord Stimulation (SCS) provides satisfaction to almost 2/3 of Persistent Spinal Pain Syndrome-Type 2 (PSPS-T2) patients implanted for refractory chronic back and/or leg pain, when not adequately addressed the back pain component, leaves patients in a therapeutic cul-de-sac. Peripheral Nerve field Stimulation (PNfS) has shown interesting results addressing back pain in the same population. Far from placing these two techniques in opposition, we suggest that these approaches could be combined to better treat PSPS-T2 patients. We designed a RCT (CUMPNS), with a 12-month follow-up, to assess the potential added value of PNfS, as a salvage therapy, in PSPS-T2 patients experiencing a "Failed SCS Syndrome" in the back pain component. Fourteen patients were included in this study and randomized into 2 groups ("SCS + PNfS" group/n = 6 vs. "SCS only" group/n = 8). The primary objective of the study was to compare the percentage of back pain surface decrease after 3 months, using a computerized interface to obtain quantitative pain mappings, combined with multi-dimensional SCS outcomes. Back pain surface decreased significantly greater for the "SCS + PNfS" group (80.2% ± 21.3%) compared to the "SCS only" group (13.2% ± 94.8%) (p = 0.012), highlighting the clinical interest of SCS + PNfS, in cases where SCS fails to address back pain.

Persistent Spinal Pain Syndrome Type 2 (PSPS-T2), a Social Pain? Advocacy for a Social Gradient of Health Approach to Chronic Pain

The Social Gradient of Health (SGH), or position in the social hierarchy, is one of the major determinants of health. It influences the development and evolution of many chronic diseases. Chronic pain dramatically affects individual and social condition. Its medico-economic impact is significant and worldwide. Failed Back Surgery Syndrome or Persistent Spinal Pain Syndrome type 2 (PSPS-T2) represents one of its most fascinating and disabling conditions. However, the influence of SGH on PSPS-T2 has been poorly explored. We designed a prospective multicentric study (PREDIBACK study) to assess the SGH prevalence, and to examine its association with medical and psychological variables, in PSPS-T2 patients. This study included 200 patients to determine the SGH association with pain (NPRS), Quality of life (EQ-5D-5L), kinesiophobia (FABQ-Work), catastrophism (CSQ), and functional capacity (ODI). Around 85.3% of PSPS-T2 patients in our study had low SGH. Low SGH patients had a higher FABQ-Work and CSQ-Catastrophizing score than high SGH patients (p < 0.05). High SGH patients have a higher ODI score than low SGH patients (p < 0.10). Our results suggest that SGH is a relevant factor to guide prevention, research, and ultimately intervention in PSPS-T2 patients and could be more widely transposed to chronic pain.

Intraoperative anti-inflammatory drugs combined with no drainage after MIS-TLIF in the treatment of recurrent lumbar disc herniation: an RCT

Background

Minimally invasive-transforaminal lumbar interbody fusions (MIS-TLIF), in which the nerve root pain is caused by early postoperative edema reaction, is a common clinical complication. However, there is no effective method to solve this problem. We aimed to use gelatin sponge impregnated with mixed anti-inflammatory drugs combined with no drainage after MIS-TLIF to optimize postoperative effect in the treatment of recurrent lumbar disc herniation (LDH).

Methods

From June 2018, the middle-aged patients (45–60 years old) with recurrent LDH were recruited. Included patients were treated with MIS-TLIF surgery, and no drainage tube was placed after surgery. All patients were randomly divided into intervention group (gelatin sponge impregnated with mixed anti-inflammatory drugs) and control group (saline was immersed in gelatin sponge as a control).

Results

The intervention group included 63 cases, and the control group included 65 cases. The length of hospital stays and bedridden period in the intervention group were significantly lower than those in the control group (P < 0.05). The VAS score of low back pain in the intervention group was significantly lower than that of the control group at postoperative days 1–6 (P < 0.05, for all). The VAS scores of leg pain in the intervention group at postoperative days 1–9 were statistically lower than the control group (P < 0.05, for all).

Conclusions

Application of gelatin sponge impregnated with mixed anti-inflammatory drugs combined with no drainage after MIS-TLIF can significantly further optimize the surgical effect of recurrent LDH and shorten the bedridden period and hospital stays, to achieve the purpose of early rehabilitation.

Trial registration

China Clinical Trial Registration Center, ChiCTR1800016236. Registered on May 21, 2018, http://www.chictr.org.cn/listbycreater.aspx

How Should we Use Multicolumn Spinal Cord Stimulation to Optimize Back Pain Spatial Neural Targeting? A Prospective, Multicenter, Randomized, Double-Blind, Controlled Trial (ESTIMET Study)

BACKGROUND

Recent studies have highlighted multicolumn spinal cord stimulation (SCS) efficacy, hypothesizing that optimized spatial neural targeting provided by new-generation SCS lead design or its multicolumn programming abilities could represent an opportunity to better address chronic back pain (BP).

OBJECTIVE

To compare multicolumn vs. monocolumn programming on clinical outcomes of refractory postoperative chronic BP patients implanted with SCS using multicolumn surgical lead.

MATERIALS AND METHODS

Twelve centers included 115 patients in a multicenter, randomized, double-blind, controlled trial. After randomization, leads were programmed using only one or several columns. The primary outcome was change in BP visual analogic scale (VAS) at six months. All patients were then programmed using the full potential of the lead up until 12-months follow-up.

RESULTS

At six months, there was no significant difference in clinical outcomes whether the SCS was programmed using a mono or a multicolumn program. At 12 months, in all patients having been receiving multicolumn SCS for at least six months (n = 97), VAS decreases were significant for global pain (45.1%), leg pain (55.8%), and BP (41.5%) compared with baseline (p < 0.0001).

CONCLUSION

The ESTIMET study confirms the significant benefit experienced on chronic BP by patients implanted with multicolumn SCS, independently from multicolumn lead programming. These good clinical outcomes might result from the specific architecture of the multicolumn lead, giving the opportunity to select initially the best column on a multicolumn grid and to optimize neural targeting with low-energy requirements. However, involving more columns than one does not appear necessary, once initial spatial targeting of the "sweet spot" has been achieved. Our findings suggest that this spatial concept could also be transposed to cylindrical leads, which have drastically improved their capability to shape the electrical field, and might be combined with temporal resolution using SCS new modalities.

Optimizing the Management and Outcomes of Failed Back Surgery Syndrome: A Proposal of a Standardized Multidisciplinary Team Care Pathway

Failed back surgery syndrome (FBSS) is a major, worldwide health problem that generates considerable expense for healthcare systems. A number of controversial issues concerning the management of FBSS are regularly debated, but no clear consensus has been reached. This pitfall is the result of lack of a standardized care pathway due to insufficient characterization of underlying pathophysiological mechanisms, which are essential to identify in order to offer appropriate treatment, and the paucity of evidence of treatment outcomes. In an attempt to address the challenges and barriers in the clinical management of FBSS, an international panel of physicians with a special interest in FBSS established the Chronic Back and Leg Pain (CBLP) Network with the primary intention to provide recommendations through consensus on how to optimize outcomes. In the first of a series of two papers, a definition of FBSS was delineated with specification of criteria for patient assessment and identification of appropriate evaluation tools in order to choose the right treatment options. In this second paper, we present a proposal of a standardized care pathway aiming to guide clinicians in their decision-making on how to optimize their management of FBSS patients. The utilization of a multidisciplinary approach is emphasized to ensure that care is provided in a uniform manner to reduce variation in practice and improve patient outcomes.

Optimizing the Management and Outcomes of Failed Back Surgery Syndrome: A Consensus Statement on Definition and Outlines for Patient Assessment

Failed back surgery syndrome (FBSS) is a controversial term for identifying patients affected by new, recurrent, or persistent pain in the low back and/or legs following spinal surgery. The lack of a comprehensive standardized care pathway compromises the appropriate management of FBSS patients, which is associated with a heavy financial burden. An international panel of spine surgeons, neurosurgeons, and pain specialists with a particular interest in FBSS established the chronic back and leg pain (CBLP) network with the aim of addressing the challenges and barriers in the clinical management of FBSS patients by building a common transdisciplinary vision. Based on literature reviews, additional input from clinical expertise of multiple professional disciplines, and consensus among its members, the network attempted to provide recommendations on the management of patients with FBSS utilizing a multidisciplinary team (MDT) approach. The presentation of this work has been divided in two separate parts to enhance its clarity. This first paper, in favour of selecting appropriate validated tools to improve the FBSS patient assessment, focuses on FBSS taxonomy and its clinical implications for evaluation. Concise recommendations for assessment, treatment, and outcome evaluation using a MDT approach would be an important resource for specialists and nonspecialist clinicians who manage patients with FBSS, to improve decision-making, reduce variation in practice, and optimize treatment outcomes in this difficult-to-treat population.

The appropriate management of persisting pain after spine surgery: a European panel study with recommendations based on the RAND/UCLA method

PURPOSE

Management of patients with persisting pain after spine surgery (PPSS) shows significant variability, and there is limited evidence from clinical studies to support treatment choice in daily practice. This study aimed to develop patient-specific recommendations on the management of PPSS.

METHODS

Using the RAND/UCLA appropriateness method (RUAM), an international panel of 6 neurosurgeons, 6 pain specialists, and 6 orthopaedic surgeons assessed the appropriateness of 4 treatment options (conservative, minimally invasive, neurostimulation, and re-operation) for 210 clinical scenarios. These scenarios were unique combinations of patient characteristics considered relevant to treatment choice. Appropriateness had to be expressed on a 9-point scale (1 = extremely inappropriate, 9 = extremely appropriate). A treatment was considered appropriate if the median score was ≥ 7 in the absence of disagreement (≥ 1/3 of ratings in each of the opposite sections 1-3 and 7-9).

RESULTS

Appropriateness outcomes showed clear and specific patterns. In 48% of the scenarios, exclusively one of the 4 treatments was appropriate. Conservative treatment was usually considered appropriate for patients without clear anatomic abnormalities and for those with new pain differing from the original symptoms. Neurostimulation was considered appropriate in the case of (predominant) neuropathic leg pain in the absence of conditions that may require surgical intervention. Re-operation could be considered for patients with recurrent disc, spinal/foraminal stenosis, or spinal instability.

CONCLUSIONS

Using the RUAM, an international multidisciplinary panel established criteria for appropriate treatment choice in patients with PPSS. These may be helpful to educate physicians and to improve consistency and quality of care. These slides can be retrieved under Electronic Supplementary Material.

Evaluation of pulsed electromagnetic field therapy for the treatment of chronic postoperative pain following lumbar surgery: a pilot, double-blind, randomized, sham-controlled clinical trial

Background

The incidence of chronic postoperative pain following lumbar spinal surgery has increased with the overall increase in the prevalence of lumbar surgery. This study was conducted to evaluate the analgesic effectiveness of pulsed electromagnetic field (PEMF) therapy in subjects with persistent pain following lumbar surgery.

Patients and methods

A randomized, double-blind, sham-controlled, multicenter study in 36 subjects with persistent low-back and/or radiating leg pain after lumbar surgery was conducted. Eligible subjects were randomized (1:1:1) to receive one of two doses of therapy (42-μs or 38-μs pulse width) or treatment with a sham device. Subjects self-treated twice daily for 60 days. The primary end point was change in pain intensity (∆PI) using the Numerical Pain Rating Scale between average baseline (Days −5 to −1) and end of treatment (Days 56–60) for lumbar and radiating leg pain. Secondary outcome measures included the Oswestry Disability Index, Beck Depression Inventory-II, Patient Global Impression of Change, and consumption of analgesics.

Results

Low-back pain scores for the 42-μs group decreased by 40.2% (p = 0.028), compared to 18.6% for the 38-μs pulse width group (p = 0.037) and 25.6% for the sham group (p = 0.013 per protocol population). Average leg pain scores decreased by 45.0% (42 μs, p = 0.009), 17.0% (38 μs, p = 0.293), and 24.5% (sham, p = 0.065). The proportion of subjects responding to therapy, time to 30% reduction in pain scores, and Patient Global Impression of Change were improved with the PEMF 42-μs device over the sham control, although results were associated with p-values >0.05.

Conclusion

PEMF therapy (42-μs pulse width) was associated with trends for a reduction in pain, compared to sham treatment. Secondary endpoints were consistent with an overall beneficial effect of the PEMF 42-μs pulse width device.

Application of Gelatin Sponge Impregnated with a Mixture of 3 Drugs to Intraoperative Nerve Root Block to Promote Early Postoperative Recovery of Lumbar Disc Herniation

OBJECTIVE

To observe effect of application of gelatin sponge impregnated with a mixture of 3 drugs to intraoperative nerve root block to promote early postoperative recovery of lumbar disc herniation.

METHODS

Retrospective analysis was performed of 265 patients with single-level lumbar disc herniation from January 2013 to October 2017. Patients were divided into intervention and control groups based on intraoperative application of gelatin sponge impregnated with a mixture of 3 drugs. All patients underwent unilateral minimally invasive surgical transforaminal lumbar interbody fusion. Clinical data, including bedridden period, postoperative hospital stay, visual analog scale scores for low back pain and leg pain, Japanese Orthopaedic Association score, postoperative satisfaction questionnaire results, and therapeutic effect, were collected.

RESULTS

There were 136 cases in the intervention group and 129 cases in the control group. The intervention group had significantly shorter bedridden period and postoperative hospital stay than control group (P < 0.05). Visual analog scale scores for low back pain and leg pain at postoperative days 1-10 were significantly lower in the intervention group compared with control group (P < 0.05). The Japanese Orthopaedic Association score at postoperative day 6 and satisfaction at 72 hours postoperatively were significantly higher in the intervention group than in control group (P < 0.05). Clinical effect at postoperative day 6 was significantly better in the intervention group than control group (P < 0.05).

CONCLUSIONS

Application of gelatin sponge impregnated with a mixture of 3 drugs to intraoperative nerve root block can significantly promote early postoperative recovery of lumbar disc herniation and has great short-term clinical efficacy.

Rehabilitation management of low back pain - it's time to pull it all together!

In the past, rehabilitation research initiatives for low back pain (LBP) have targeted outcome enhancement through personalized treatment approaches, namely through classification systems (CS). Although the use of CS has enhanced outcomes, common management practices have not changed, the prevalence of LBP is still high, and only selected patients meet the CS profile, namely those with a nociceptive context. Similarly, although practice guidelines propose some level of organization and occasionally a timeline of care provision, each mainly provides best practice for isolated treatment approaches. Moreover, there is no theoretical framework that has been proposed that guides the rehabilitation management process of mechanical LBP. In this commentary, we propose a model constituted of five domains (nociceptive drivers, nervous system dysfunction drivers, comorbidities drivers, cognitive–emotional drivers, and contextual drivers) grounded as mechanisms driving pain and/or disability in LBP. Each domain is linked to the International Classification of Functioning, Disability and Health, where once a patient is deemed suitable for rehabilitation, the clinician assesses elements of each domain in order to identify where the relative treatment efforts should be focused. This theoretical model is designed to provide a more comprehensive management overview, by appreciating the relative contribution of each domain driving pain and disability. Considering that the multiple domains driving pain and disability, and their interaction, requires a model that is comprehensive enough to identify and address each related issue, we consider that the proposed model has several positive implications for rehabilitation of this painful and highly prevalent musculoskeletal disorder.

Chiropractic Distraction Spinal Manipulation on Postsurgical Continued Low Back and Radicular Pain Patients: A Retrospective Case Series

PURPOSE

The purpose of this case series is to report on changes in pain levels experienced by 69 postsurgical continued pain patients who received Cox Technic Flexion Distraction (CTFD).

METHODS

Fifteen doctors of chiropractic collected retrospective data from the records of the postsurgical continued pain patients seen in their clinic from February to July 2012 who were treated with CTFD, which is a type of chiropractic distraction spinal manipulation. Informed consent was obtained from all patients who met the inclusion criteria for this study. Data recorded included subjective patient pain levels at the end of the treatments provided and at 24 months following the last treatment.

RESULTS

Fifty-four (81%) of the patients showed greater than 50% reduction in pain levels at the end of the last treatment, and 13 (19%) showed less than 50% improvement of pain levels at the end of active care (mean, 49 days and 11 treatments). At 24-month follow-up, of 56 patients available, 44 (78.6%) had continued pain relief of greater than 50% and 10 (18%) reported 50% or less relief. The mean percentage of relief at the end of active care was 71.6 (SD, 23.2) and at 24 months was 70 (SD, 25). At 24 months after active care, 24 patients (43%) had not sought further care, and 32 required further treatment consisting of chiropractic manipulation for 17 (53%), physical therapy, exercise, injections, and medication for 9 (28%), and further surgery for 5 (16%).

CONCLUSION

Greater than 50% pain relief following CTFD chiropractic distraction spinal manipulation was seen in 81% of postsurgical patients receiving a mean of 11 visits over a 49-day period of active care.

Failed back surgery syndrome: review and new hypotheses

Failed back surgery syndrome (FBSS) is a term used to define an unsatisfactory outcome of a patient who underwent spinal surgery, irrespective of type or intervention area, with persistent pain in the lumbosacral region with or without it radiating to the leg. The possible reasons and risk factors that would lead to FBSS can be found in distinct phases: in problems already present in the patient before a surgical approach, such as spinal instability, during surgery (for example, from a mistake by the surgeon), or in the postintervention phase in relation to infections or biomechanical alterations. This article reviews the current literature on FBSS and tries to give a new hypothesis to understand the reasons for this clinical problem. The dysfunction of the diaphragm muscle is a component that is not taken into account when trying to understand the reasons for this syndrome, as there is no existing literature on the subject. The diaphragm is involved in chronic lower back and sacroiliac pain and plays an important role in the management of pain perception.

Intrathecal Hydromorphone and Bupivacaine Combination Therapy for Post-Laminectomy Syndrome Optimized with Patient-Activated Bolus Device

BACKGROUND

Intrathecal (IT) pumps have become a valuable tool in managing intractable non-cancer pain. The purpose of this study was to evaluate the efficacy of using a rigorous treatment algorithm for trialing and implanting IT pumps with hydromorphone and bupivacaine in managing a more homogeneous population of post-laminectomy syndrome or failed back surgery syndrome (FBSS) patients.

METHODS

This is a retrospective analysis of FBSS patients with chronic intractable back pain implanted with IT pumps delivering hydromorphone and bupivacaine.

RESULTS

A cohort of 57 (26 males, 31 females) consecutively implanted FBSS patients was analyzed. The average age at implant was 65.4 years. Average pain scores were 8.4 ± 0.2 (pre-implant), 4.9 ± 0.4 (6 months), 5.2 ± 0.5 (12 months), and 4.3 ± 0.5 (24 months). Average oral opioid doses in morphine equivalents were 56 ± 10 mg/day (pre-implant), 12.0 ± 3.5 mg/day (12 months), 15 ± 6 mg/day (24 months). Average IT hydromorphone doses were 79 ± 6.8 mcg/day (at implant), 184 ± 22 mcg/day (6 months), 329 ± 48 mcg/day (12 months), and 487 ± 80 mcg (24 months). IT hydromorphone dose escalation from baseline was 133% (6 months vs baseline), 78% (12 months vs 6 months), and 48% from 12 months to 24 months. Average IT bupivacaine doses were 5.8 ± 0.3 mg/day (implant), 9.5 ± 0.6 mg/day (6 months), 12.2 ± 0.7 mg/day (12 months), and 12.6 ± 0.9 mg/day (24 months).

CONCLUSION

IT hydromorphone and bupivacaine are effective in treating chronic pain of FBSS, as demonstrated by the reduction of pain intensity and oral opioid consumption. However, an IT dose escalation phenomenon was observed, although at a reduced rate compared with what had been previously reported in the literature. It is possible that the local anesthetic combination delivered via a patient-activaed bolus device is an important factor. Despite demonstrating effectiveness, the clinical utility of myPTM-optimized IT therapy remains limited by a lack of prospective, placebo-controlled trials and comparative effectiveness research.

The Effects of Local Anesthesia Administration on Pain Experience During Interventional Spine Procedures: A Prospective Controlled Trial

OBJECTIVE

It has been postulated that local anesthetic administration may be the most painful part of interventional spine procedures. Despite this, there is a lack of evidence supporting the commonly used traditional technique of anesthetic delivery as part of these procedures. This study tested three hypotheses: 1) alternative method of local anesthesia injection is superior to the traditional method; 2) using the traditional method of injection is not superior to using no local anesthetic; and 3) treatment needle size, anesthetic injection technique, and sedation are associated with pain experienced during procedures.

DESIGN

Prospective, multicenter clinical trial of 127 participants who underwent elective bilateral symmetric interventional spine procedures in outpatient spine clinics.

METHODS

Primary outcomes were pain scores during and after procedures to examine the influence of anesthetic injection method and treatment needle gauge on pain experience using linear mixed model regression analysis. A post-hoc comparison of estimated marginal mean pain scores was completed on both anesthetic injection method and treatment needle gauge.

CONCLUSIONS

The alternative method was superior (P < 0.05) to the traditional method on post procedural pain scores. Injecting local anesthetic with the traditional or alternative method was not superior to using no local anesthetic. Treatment needle size, pain at one inch of treatment needle insertion, and baseline pain were all significantly (P < 0.05) associated with overall procedural pain. Further studies are needed optimize and justify local anesthetic injections for these procedures.