Primary Pain Generator Research Articles

BERTOLOTTI'S SYNDROME: DIAGNOSIS AND TREATMENT

IntroductionLumbosacral transitional vertebrae (LSTV) are increasingly recognized as a common anatomical variant and is the most common congenital anomaly of the lumbosacral spine. Patients can have symptomatic LSTV, known as Bertolotti's Syndrome, where transitional anatomy can cause back, L5 distribution leg, hip, and groin pain. We propose an outline for diagnosis and treatment of Bertolotti's Syndrome.MethodsWe retrospectively reviewed over 500 patients presenting to the primary author with low back, buttock, hip, groin and/or leg pain from April 2009 through April 2024. Patients with radiographic findings of an LSTV and clinical presentation underwent diagnostic injections to confirm diagnosis of Bertolotti's syndrome. Treatment was determined based on patient's LSTV classification. 157 patients with confirmed Bertolotti's syndrome underwent surgical treatment.ResultsOver 500 patients presented with an appropriate clinical presentation and radiographic findings of an LSTV. Diagnostic injections were targeted into the transitional anatomy confirming the LSTV as the primary pain generator to make the diagnosis of Bertolotti's syndrome. The decision in the type of surgical intervention, resection or fusion, was made based on patient's LSTV anatomy. 157 patients with confirmed Bertolotti's Syndrome underwent surgical treatment (121 fusions (77%), 36 resections (23%)). The classification system and surgical outcomes, in part, have been previously published in World Neurosurgery.ConclusionWe have outlined the best practice of diagnosis and treatment selection for Bertolotti's syndrome. We have shown significant improvement in outcomes based on this method. We hope to aid in both patient education and provide an outline on how clinicians can become knowledgeable on Bertolotti's syndrome.Conflicts of interestNo conflicts of interestSources of fundingNo funding obtained

Redefining the Classification for Bertolotti Syndrome: Anatomical Findings in Lumbosacral Transitional Vertebrae Guide Treatment Selection

We present the Jenkins classification for Bertolotti syndrome or symptomatic lumbosacral transitional vertebra (LSTV) and compare this with the existing Castellvi classification for patients presenting for treatment. We performed a retrospective cohort study of 150 new patients presenting for treatment of back, hip, groin, and/or leg pain from July 2012 through February 2022. Using magnetic resonance imaging, computed tomography, and radiography, the patients with a radiographic finding of LSTV, an appropriate clinical presentation, and identification of LSTV as the primary pain generator via diagnostic injections were diagnosed with Bertolotti syndrome. Patients for whom conservative treatment had failed and who underwent surgery to address their LSTV were included in the present study. The Castellvi classification excludes 2 types of anatomic variants: the prominent anatomic side and the potential transverse process and iliac crest contact. Of 150 patients with transitional anatomy, 103 (69%) were identified with Bertolotti syndrome using the Jenkins classification and received surgery (46 men [45%] and 57 women [55%]). Of the 103 patients, 90 (87%) underwent minimally invasive surgery. The patients presented with pain localized to the back (n= 101; 98%), leg (n= 79; 77%), hip (n= 51; 49%), and buttock (n= 52; 50%). Only 84 of the Jenkins classification patients (82%) met any of the Castellvi criteria. All 19 patients for whom the Castellvi classification failed had had type 1 anatomy using the Jenkins system and underwent surgery (decompression, n= 16 [84%]; fusion, n= 1 [5%]; fusion plus decompression, n= 2 [11%]). Of these 19 patients, 17 (89%) had improved pain scores. The 19 patients exclusively diagnosed via the Jenkins classification had no significant differences in improved pain compared with those diagnosed using the Castellvi classification. The Jenkins classification improves on the prior Castellvi classification to more comprehensively describe the functional anatomy, identify uncaptured anatomy, and better predict optimal surgical procedures to treat those with Bertolotti syndrome.

Far-Contralateral Oblique (FCO) Sacroiliac Joint Injection: Description of a Novel Technique

Sacroiliac (SI) joint arthropathy is the primary pain generator in approximately 15–25% of patients with axial low back pain and traditionally diagnosed with >50% pain reduction following an intra-articular injection localized to the inferior 1/3 of the SI joint. The conventional technique for accessing the SI joint encompasses a posterior approach with fluoroscopic guidance at 10–20⁰ contralateral oblique angulation, and minor adjustments to this approach have been implemented with varying degrees of success. The authors present a novel technique for SI joint injection, infiltrating the middle third of the joint through an alternative far-contralateral oblique (FCO) approach, angulation between 20–40⁰. This approach theoretically endows easier access to the SI joint and at the very least provides another option for interventionalists in the diagnosis and treatment of sacroiliac joint pain. It can also be utilized to determine if a patient is a candidate for posterior percutaneous SI joint fusion. The authors sought to document this approach to ensure that it was both reproducible and safe, while recognizing the need for future studies.

Piriformis Syndrome Masquerading as an Ischiofemoral Impingement

Hip pain can have a number of different etiologies. Ischiofemoral impingement (IFI), an etiology causing extra-articular hip pain, shares many of the same symptoms as other causes of gluteal or inguinal pain, making its diagnosis difficult. We present a case of a young female with persistent deep gluteal pain who was diagnosed with IFI based on radiographic findings; however, a diagnostic injection into the quadratus femoris did not confirm IFI as the primary pain generator. The patient subsequently failed several trials of physical therapy designed to address this diagnosis. The diagnosis was expanded to include piriformis syndrome and the modified treatment approach resulted in complete resolution of her pain. The similarities of these pathologies resulted in a delay of definitive treatment and would have potentially required unnecessary surgery. This case study highlights the diagnostic conundrum clinicians face in the evaluation of gluteal hip pain and provides an algorithm for considering alternate diagnoses when conservative management fails to achieve expected results.

Musculoskeletal ultrasonographic evaluation of perineural injection therapy versus therapeutic ultrasound in chronic lateral epicondylitis

BackgroundLateral epicondylitis (LE) is a common disorder causing pain and functional limitations especially in athletes and manual workers. There is a growing interest in regenerative injection therapies in chronic LE. One of those suggested is perineural injection (PNI) therapy. The present study aims to find out the efficacy of PNI therapy in the treatment of chronic LE as compared to therapeutic ultrasound (TUS) and to detect if any changes have happened after treatment to the common extensor tendon (CEO) as detected by diagnostic ultrasound (US) examination.ResultsStatistical analysis between the 2 groups at the start of the study as regards age, sex, and clinical parameters including visual analog scale (VAS), tenderness grading scale, and Patient-Rated Tennis Elbow Evaluation (PRTEE) Questionnaire revealed a non-significant difference between both groups (p > 0.05). After 12 weeks, within-group analysis showed significant improvement in all clinical outcome measures in both groups compared to the initial assessment.Between-group analysis after 12 weeks showed that the tenderness grading scale and PRTEE score had more significant improvement in the PNI therapy group. However, the two groups were comparable regarding VAS. Within-group US evaluation at the 12th week post-treatment showed a highly significant decrease in hypoechoic areas (p < 0.001) and a decrease in distributed fibrillar pattern in PNI group, while the TUS group demonstrated a significant decrease in hypoechoic areas and tendon thickness (p < 0.005). Between-group US evaluation after 12 weeks showed no significant difference in all assessed US parameters. No complications were observed in both groups.ConclusionsA short-term follow-up regimen of 1 session/week of PNI therapy is significantly more effective than 3 sessions/week of TUS regarding the improvement of pain and functional status. Yet both therapeutic modalities were able to produce significantly positive structural changes in the CEO. The current study highlights the neurogenic inflammation as the primary pain generator in chronic LE and the advantage of its treatment with PNI therapy in chronic and refractory cases.

Update on Evidence-Based Diagnosis and Treatment of Acetabular Labral Tears

This paper aims to assess the pathophysiology, diagnosis, and latest evidence-based treatment of acetabular labral tears. The acetabular labrum contributes to the stability of the hip. Labral tears may lead to significant pain and disability, although many are asymptomatic. Imaging and intra-articular injections are often required in addition to standard history and physical examination for accurate diagnosis. Most patients will benefit from initial conservative treatment, but those requiring surgical intervention may have better outcomes with labral repair over debridement. If the labral tear is irreparable, reconstruction is favored. There is still conflicting evidence regarding the efficacy of surgical versus non-surgical treatment likely due to heterogeneity of pathology, patient activity, and lack of long-term follow up. The approach to management of acetabular labral tears starts with confirming the labrum as the primary pain generator. Most patients benefit from initial conservative treatment. Ultimately, the decision for surgical treatment is dependent on correct patient selection. Those patients who are youger, with bony morphologic changes, a higher activity level, an isolated labral tear without significant cartilage degeneration, and good response to intra-articular diagnostic injection will likely have better outcomes with surgical treatment.

Adipose Tissue as Pain Generator in the Lower Back and Lower Extremity: Application in Musculoskeletal Medicine.

Description Adipose tissue (AT) has diverse and important functions in body insulation, mechanical protection, energy metabolism and the endocrine system. Despite its relative abundance in the human body, the clinical significance of AT in musculoskeletal (MSK) medicine, particularly its role in painful MSK conditions, is under-recognized. Pain associated with AT can be divided into intrinsic (AT as a primary pain generator), extrinsic (AT as a secondary pain generator) or mixed origin. Understanding AT as an MSK pain generator, both by mechanism and its specific role in pain generation by body region, enhances the clinical decision-making process and guides therapeutic strategies in patients with AT-related MSK disorders. This article reviews the existing literature of AT in the context of pain generation in the lower back and lower extremity to increase clinician awareness and stimulate further investigation into AT in MSK medicine.

179. Propensity-matched analysis of 1,062 patients following minimally invasive versus open sacroiliac joint fusion

BACKGROUND CONTEXT The sacroiliac joint (SIJ) has been identified as a primary pain generator in a considerate proportion of low back pain (LBP) patients. Many patients turn to SIJ fusion after failure of conservative care to relieve SIJ pain. There are two surgical options for fusing the SIJ; an open or minimally invasive (MIS) approach. The open approach typically results in higher rates of postoperative complications and less improvement in patient reported pain and disability scores. PURPOSE The purpose of this study was to analyze the associated costs and postoperative complications of MIS and open approaches to SIJ fusion. STUDY DESIGN/SETTING Propensity-matched retrospective cohort study using the 2016-2017 National Readmission Database. PATIENT SAMPLE After excluding for all patients who had a prior SIJ fusion, those diagnosed with prior neoplasms or trauma of the pelvis and/or sacrum, and individuals whose primary SIJ fusion was nonelective, we identified 2,521 patients who received a SIJ fusion with an open (n=1,990) or MIS approach (n=531) for diagnosed sacrum pain, sacroiliitis, sacral instability or spondylosis. We then one-to-one propensity-matched the open (n=531) to the MIS approach (n=531) for age, sex and Charlson Comorbidity Index (CCI). OUTCOME MEASURES Costs, surgical outcomes, non-elective readmission rate, 30-, 90- and 180-day postoperative complications. METHODS We collected all of the individuals that had a non-elective readmission, separated them by surgical approach, and analyzed associated costs, surgical outcomes, non-elective readmission rate, 30-, 90- and 180-day postoperative complications. Statistical analysis was conducted in RStudio, with Welch two sample t-tests to compare complications and costs by surgical approach. RESULTS The mean cost of open SIJ fusion and was significantly higher compared to the MIS group (open $101,061.90 ±$81,136.67; MIS $83,594.78 ± $49,086.00, p CONCLUSIONS The current study found that MIS SIJ fusion was significantly less expensive than open SIJ fusion and was associated with less costly readmissions. Although no significant differences in postoperative outcomes were found, there were several notable trends specific to each surgical approach. Further investigation is required to fully characterize the potential advantages and disadvantages of the two surgical approaches. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Primary pain generator identification by CT-SPECT in patients with degenerative spinal disease.

Axial spinal pain generators are difficult to identify using current diagnostic modalities. Merging CT with SPECT (CT-SPECT) scans allows for accurate identification of areas with increased osteoblastic activity, which may reflect pain generators. In this study, the authors aimed to evaluate the degree of pain improvement in patients who underwent surgery, addressing primary pain generators identified by CT-SPECT. The authors retrospectively reviewed all patients with chronic axial spine pain who underwent diagnostic CT-SPECT at their institution and analyzed pain improvement in those who underwent surgical treatment in order to determine whether CT-SPECT correctly identified the primary pain generator. A total of 315 patients underwent diagnostic CT-SPECT between January 2014 and August 2018. Forty-eight patients underwent either cervical or lumbar fusion; there were 26 women (16 cervical, 10 lumbar) and 22 men (9 cervical, 13 lumbar). The overall axial spinal pain, as assessed through self-reporting of visual analog scale scores at 6 months postoperatively, improved from 9.04 ± 1.4 to 4.34 ± 2.3 (p = 0.026), with cervical fusion patients improving from 8.8 ± 1.8 to 3.92 ± 2.2 (p = 0.019) and lumbar fusion patients improving from 9.35 ± 0.7 to 4.87 ± 2.3 (p = 0.008). CT-SPECT may offer a diagnostic advantage over current imaging modalities in identifying the primary pain generator in patients with axial spinal pain.

A Review of Hip-Spine Syndrome

This review is aimed at summarizing our current understanding of hip-spine syndrome. In particular, the review discusses the clinical assessment and diagnosis of commonly implicated conditions to help a practitioner realize an efficient and organized approach to the evaluation and management of pain in the setting of hip-spine syndrome. While initially described as the concurrent presence of hip osteoarthritis and lumbar spinal stenosis, the catalog of diagnoses associated with hip-spine syndrome has expanded and includes femoroacetabular impingement, acetabular dysplasia, hip osteoarthritis, sacroiliac joint-mediated pain, facet arthropathy, and lumbar spinal stenosis. There is a limited body of evidence describing clinical findings and treatment recommendations when these diagnoses present concurrently. From the available literature, it seems that patients may be successfully managed with a multimodal approach, although absolute resolution of symptoms is not always plausible. In the context of hip-spine syndrome, identification of a primary pain generator or etiology, when present, is important to guide successful management. Lingering symptoms may persist and can suggest the presence of a more co-dependent relationship between the hip and the spine (so-called complex hip-spine syndrome). Further research is needed to clarify the influences that underlie hip-spine syndrome, particularly in these more complex cases, and in turn better define diagnostic and treatment algorithms.

Intravaginal Diazepam for the Treatment of Pelvic Floor Hypertonic Disorder: A Double-blind, Randomized, Placebo-Controlled Trial

(Abstracted from Female Pelvic Med Reconstr Surg 2019;25:76–81) Pelvic floor hypertonic disorder is a neuromuscular condition that causes involuntary spasms of the levator ani muscles, resulting in reproducible pelvic pain during vaginal intercourse or internal pelvic examination. It may act as a primary pain generator, a singular component of pelvic pain, or cause bladder or bowel dysfunction.

Treatment of Type Two Slap Lesion With Anatomic Suture Anchor Repair Without Biceps Tenotomy Or Tenodesis.

Background:Poor results after repair of type 2 SLAP tears are relatively common and some have reported better results after biceps tenodesis or tenotomy than repair. In addition, some believe that the long head of the biceps is expendable. Therefore, many now favor biceps tenotomy or tenodesis over biceps anchor repair either in all patients or in older patients, reserving SLAP lesion repair only for young athletes.Hypothesis:We hypothesized that repair of the biceps anchor of the labrum would be effective in all patients regardless of age provided that care was taken not to overtighten the labrum and that rotator cuff pain as the primary pain generator had been ruled out.Methods:All patients with type 2 SLAP lesion repair by the senior author since he began repairing them with suture anchors were prospectively evaluated. Patients with more than one other concomitant procedure, simultaneous rotator cuff repair or worker’s compensation status were excluded.Results:77% of patients were available for minimum two year followup. No patient had subsequent surgery or manipulation under anesthesis as a result of their SLAP repair. Standardized shoulder test score increased by 4 points. Mean SANE score decreased from 53 pre-op to 14 post-op. Results were the same in those over versus under 40 years of age.Conclusion:Anatomic repair of Type 2 SLAP lesions at the biceps anchor without biceps tenodesis or tenotomy can produce good results in patients of all ages.

Primary pain generator identification by CT\u2013SPECT in a patient with low back pain: a case report

BackgroundChronic low back pain is one of the most common conditions encountered in the middle-age population. Identifying the primary pain generator is notoriously difficult. The computed tomography–single-photon emission computed tomography (CT–SPECT) is emerging as a new diagnostic modality for this purpose.Case presentationThis 68-year-old Caucasian male presented with intractable low back pain refractory to maximal conservative treatment, including medication and extensive physical therapy. The lumbar computed tomography, magnetic resonance imaging, and flexion–extension X-rays showed advanced degenerative changes throughout the lumbar spine, but no single level significantly worse than the others. The CT–SPECT showed markedly increased uptake at the L1–2 disc level and only minimal uptake at the other levels. The patient underwent a minimally invasive lateral L1–2 fusion with near-complete resolution of his low back pain.ConclusionsThe CT–SPECT may provide a unique tool in establishing the primary pain generator in patients with degenerative spine disease.

Minimally invasive facet restoration implant for chronic lumbar zygapophysial pain: 1-year outcomes.

BackgroundThe zygapophysial (facet) joint is the primary pain generator in one third of chronic low back pain cases. Current treatment options include temporarily palliative nonsurgical approaches, facet injections, radiofrequency denervation, and, rarely, lumbar arthrodesis. The purpose of this study was to assess the safety and effectiveness of a minimally invasive implant intended to restore facet joint function in patients with chronic lumbar facetogenic pain.MethodsThis prospective, multi-center feasibility study enrolled patients with confirmed lumbar facetogenic joint pain at 1 or 2 levels who underwent at least 6 months of unsuccessful nonoperative care. Patients received a minimally invasive implant (Glyder® Facet Restoration Device, Zyga Technology, Inc., Minnetonka, MN) intended to restore facet joint function while preserving the native anatomy. Main outcomes included back pain severity using a visual analogue scale, back-specific disability using the Oswestry Disability Index (ODI), and adverse events adjudicated by an independent Clinical Events Committee.ResultsOf 40 enrolled patients, 37 patients received the facet restoration implant and 34 patients had complete 1-year follow-up data available. Over the 1-year follow-up period, back pain severity decreased 41% and ODI decreased 34%, on average. Freedom from a device- or procedure-related serious adverse event through 1 year was 84%. Implant migration was observed in 3 patients and implant expulsion from the facet joint occurred in 3 patients. In total, 2 (5.4%) patients underwent implant removal through 1 year post-treatment.ConclusionsA minimally invasive facet restoration implant is a promising treatment option in select patients with chronic lumbar zygapophysial pain who have exhausted nonsurgical treatments, with therapeutic benefit persisting at 1 year follow-up.

The biceps tendon: from proximal to distal: AAOS exhibit selection.

Ding, David Y. MD1; Garofolo, Garret BS1; Lowe, Dylan MD1; Strauss, Eric J. MD1; Jazrawi, Laith M. MD1 Author Information

A Practice Audit of CT-Guided Injections of Pars Interarticularis Defects in Patients with Axial Low Back Pain: A Primer for Further Investigation

To assess whether computed tomography (CT)-guided injections of local anesthetic and corticosteroid into chronic lumbar pars interarticularis defects may identify and provide benefit to a cohort of patients where the pars defects act as a primary axial pain generator. Retrospective practice audit. Single academic radiology pain management practice. 59 consecutive patients undergoing CT-guided injections of lumbar pars defects. Patients were assessed with a pain numerical rating scale (NRS, 0-10) and Roland-Morris disability questionnaire (R-M) prior to injection and at 2 weeks and 2 months follow-up. For categorical outcomes, successful pain relief response was defined as either ≥50% reduction in NRS or pain 0/10; functional response was defined as ≥40% reduction in R-M score. Continuous outcomes (mean NRS, R-M scores) were assessed for significant change following injection. For categorical outcomes, 37.9% of patients were responders at 2 months' follow-up; 20.7 % had complete relief of index pain. For functional recovery, 34.5% were responders at 2 months. Using continuous outcomes, mean NRS was 5.4 ± 2.1 prior to injection and 3.6 ± 2.6 at 2 months (P < 0.0001). Mean R-M score was 11.7 ± 6.0 prior to injection and 9.0 ± 5.4 at 2 months (P = 0.001). There were no complications. This practice audit suggests that in patients with axial low back pain and chronic pars defects, the pars defects may be implicated as the primary axial pain generator in a small subgroup of patients. Local deposition of corticosteroids into the pars defect may provide significant pain relief in one out of three patients, and complete relief in one out of five patients. This data suggest there may be benefit to pursuing randomized controlled trials of pars injections comparing steroid injection with placebo.

Axial neck pain: a surgeon’s perspective

Neck pain is a common and difficult patient complaint. In the majority of cases, conservative treatment, including the use of pain medication, anti-inflammatories, rest, physical therapy and select injections provide the best relief of chronic pain. By elucidating the primary pain generator clinicians may be guided towards the best treatment options. Surgical treatment of axial neck pain is controversial and reported outcomes are not encouraging, with the exception of a select group of patients. This article is intended to provide the general clinician with an understanding of neck pain from a surgeon’s standpoint so that the treating physician can guide their patient’s expectations in advance of a surgical consultation. We have performed an extensive review of the English language literature discussing axial neck pain with a special focus on surgical treatment options. In addition, we give our opinion regarding both the conservative and surgical treatment of these challenging patients based on our own experience.

The usefulness of somato sensory evoked potentials in the diagnosis of persistent thoracic pain and extrinsic myelopathy

Persistent mid back pain presents a special challenge to the diagnostician, as both intrinsic- and extrinsic medullary etiologies must be considered. Upper and lower extremity Somato Sensory Evoked Potentials studies (SSEP), in their functional assessment of the relevant spinal segmental levels C4-5/N9-N13 Latency (N9-N13), T11-12/T12 Latency (T12) and L3-4/L3-P37 (L3-P37) would assist in resolving the primary pain generator, especially when correlated with EMG and neuroimaging findings. The goal of this study is to assess the value of SSEP in the diagnosis of patients with persistent mid back pain, particularly in the presence of potential extrinsic, medullary pain generators. A 30-month retrospective chart review was performed; 13 patients underwent SSEP, excluding those with intrinsic spinal cord lesions at the site of mid back pain; Results were correlated with clinical findings, paraspinal thoracic EMG and CT, MRI lesions between T1 and T12 (cord contact or impingement, calcific nodules posterior to cord, disc bulge-degeneration-herniation-protrusion, vertebral anterior wedging). Positive study criteria were: mid back pain, prolonged L3-P37 latency (NL<=20.5 ms), normal N9-N13 latency (NL<=5.77 ms), normal T12 latency (NL<=26.2 ms). Results revealed the following - Positive SSEP: 11/13 (84.6%); Positive SSEP, with correlating neuroimaging: 9/11 (81.8%); Positive SSEP, without correlating neuroimaging: 2/11 (18.2%); Positive SSEP, with correlating neuroimaging and EMG: 7/11 (63.6%); Negative SSEP: 2/13 (15.4%); EMG findings: 7/7 chronic polyphasia-reinnervation; 2/7 acute fibrillation potentials. We conclude that SSEP is a valuable diagnostic tool in the assessment of persistent mid back pain. We recommend its routine use in the evaluation of thoracic pain, particularly in patients with known thoracic spinal segmental lesions. Persistent mid back pain presents a special challenge to the diagnostician, as both intrinsic- and extrinsic medullary etiologies must be considered. Upper and lower extremity Somato Sensory Evoked Potentials studies (SSEP), in their functional assessment of the relevant spinal segmental levels C4-5/N9-N13 Latency (N9-N13), T11-12/T12 Latency (T12) and L3-4/L3-P37 (L3-P37) would assist in resolving the primary pain generator, especially when correlated with EMG and neuroimaging findings. The goal of this study is to assess the value of SSEP in the diagnosis of patients with persistent mid back pain, particularly in the presence of potential extrinsic, medullary pain generators. A 30-month retrospective chart review was performed; 13 patients underwent SSEP, excluding those with intrinsic spinal cord lesions at the site of mid back pain; Results were correlated with clinical findings, paraspinal thoracic EMG and CT, MRI lesions between T1 and T12 (cord contact or impingement, calcific nodules posterior to cord, disc bulge-degeneration-herniation-protrusion, vertebral anterior wedging). Positive study criteria were: mid back pain, prolonged L3-P37 latency (NL<=20.5 ms), normal N9-N13 latency (NL<=5.77 ms), normal T12 latency (NL<=26.2 ms). Results revealed the following - Positive SSEP: 11/13 (84.6%); Positive SSEP, with correlating neuroimaging: 9/11 (81.8%); Positive SSEP, without correlating neuroimaging: 2/11 (18.2%); Positive SSEP, with correlating neuroimaging and EMG: 7/11 (63.6%); Negative SSEP: 2/13 (15.4%); EMG findings: 7/7 chronic polyphasia-reinnervation; 2/7 acute fibrillation potentials. We conclude that SSEP is a valuable diagnostic tool in the assessment of persistent mid back pain. We recommend its routine use in the evaluation of thoracic pain, particularly in patients with known thoracic spinal segmental lesions.

Notochordal Cells Influence Gene Expression of Inflammatory Mediators of Annulus Fibrosus Cells in Proinflammatory Cytokines Stimulation

Notochordal cells in the intervertebral disc interact with nucleus pulposus (NP) cells and support the maintenance of disc homeostasis by regulation of matrix production. However, the influence of notochordal cells has not been evaluated in the annulus fibrosus (AF), which is the primary pain generator in the disc. We hypothesized that the notochordal cell has the capacity to modulate inflammatory mediators secreted by AF cells secondary to stimulation. Notochordal and AF cells were isolated from adult New Zealand white rabbits. AF pellets were cultured with notochordal cell clusters or in notochordal cell-conditioned media (NCCM) for 24 or 48 hours with proinflammatory cytokines at varying concentrations. Gene expression in AF pellets were assayed for nitric oxide synthase (iNOS), cyclo-oxygenase (COX)-2, and interleukin (IL)-6 by real time reverse transcriptase polymerase chain reaction (RT-PCR). AF pellet in NCCM significantly decreased the iNOS and COX-2 messenger ribonucleic acid (mRNA) levels compared to AF pellets alone and AF pellets with notochordal cells (p < 0.05). AF pellet resulted in dose-dependent iNOS and COX-2 expression in response to IL-1beta, stimulation, demonstrating that 1 ng/ml for 24 hours yielded a maximal response. AF pellet in NCCM significantly decreased the expression of iNOS and COX-2 in response to 1ng/ml IL-1beta, stimulation at 24 hours (p < 0.05). There was no difference in IL-6 expression compared to AF pellets alone or AF pellets with notochordal cell clusters. We conclude that soluble factors from notochordal cells mitigate the gene expression of inflammatory mediators in stimulated AF, as expected after annular injury, suggesting that notochordal cells could serve as a novel therapeutic approach in symptomatic disc development.

How Often Is Low Back Pain Not Coming From the Back?

Consecutive case series cohort. To determine the relative frequencies of the spine, the sacroiliac (SI) joint, and the hip joint being the primary pain generator among patients presenting at a spine surgery clinic for low back pain (LBP). Identification of the primary pain generator in a patient with LBP is difficult. Possible pain sources include the lumbar spine, the SI joint, and the hip joint. Their relative frequencies among patients presenting at a spine surgeon's clinic have not been well established. Three hundred sixty-eight new patients were seen at a single spine surgeon's clinic during a 10-month period. Of these, 289 (78.5%) complained primarily of LBP with or without leg pain. Seventy-seven had previous surgery. The remaining 200 cases were reviewed for all diagnostic tests performed, as well as the final diagnosis. One hundred sixty-four (82%) had spine pathology, but only 130 (65%) had spine-only pathology, whereas 35 (17.5%) had a combination of spine plus hip and/or SI joint pathology. An additional 16 (8%) had hip and/or SI joint pathology without spine pathology. Twenty (10%) had an undefined pain source. Overall, 25 (12.5%) had hip pathology, and 29 (14.5%) had SI joint pathology. For patients presenting to a spine surgeon's clinic for LBP, up to 25% of patients may have significant pain contribution from the hip or SI joints, and an additional 10% will still have an undefined pain source even after diagnostic workup. This underscores the need for clinicians to be aware of nonspinal pain generators and to appropriately pursue alternative diagnoses.