An analysis of radiating pain at lumbar discography

This study aimed to identify the morphological abnormalities of the intervertebral disc, as demonstrated by lumbar discography, that are associated with pain radiation to the hip, groin, buttock or lower limb. We carried out a retrospective review of 99 consecutive lumbar discogram reports. The association of disc degeneration, annular tears (partial or full thickness) and the level of disc injected was determined with respect to the presence and pattern of radiating pain. A total of 260 discs were injected, of which 179 were considered abnormal. Posterior annular tears were demonstrated in 84 discs, anterior annular tears in 15 discs and 45 discs had both anterior and posterior tears. A significant association was identified between isolated posterior tears and the production of concordant radiating pain (P = 0.0041). No difference was identified between partial thickness posterior tears and full thickness posterior tears associated with leak of contrast medium, with regard to radiating pain. Similarly, there was no significant association between disc level injected and the pattern of pain radiation. The results indicate that pain experienced in the buttock, hip, groin or lower limb can arise from the posterior annulus of the intervertebral disc without direct involvement of the nerve root. Received: 29 November 1997 Revised: 20 March 1998 Accepted: 6 April 1998     

Intervertebral disc degeneration

Summary Disc degeneration in the human spine is a complex phenomenon characterised by biochemical change in the nucleus pulposus and inner annulus and the formation of clefts and fissures radiating from the central area of the disc towards the periphery. In addition, and probably independent of these phenomena, discrete defects in the outer annular attachement are seen which are likely to be due to mechanical stress and failure. The presence of stress tears in disc tissue and their failure to heal can initiate or accelerate the degeneration of the central component of the intervertebral disc. We postulate that discogenic pain may be linked to damage to the outer portion of the annulus fibrosus. Although it would seem logical to assume that discs with sustained high intradiscal pressure would be more prone to pain referred in the outer annular layers because of higher tensile strain, analysis of prospective studies has failed to confirm a relationship between typical pain reproduction at discography and high pressure values. It is concluded that, at present, the only consistent morphological changes present in patients with pain reproduction at discography are the presence of various annular defects involving the outer layers. Whether nerve ingrowth during attempts at repair of these defects is a consistent feature remains to be established.     

腰椎间盘MRI高信号区的组织病理学特点和临床意义

目的研究椎间盘源性下腰痛患者腰椎间盘纤维环后方MRI高信号区的组织病理学特征及其临床意义。方法对52例经保守治疗无效、CT片显示无腰椎间盘突出的下腰痛患者行腰椎MR检查及腰椎间盘造影术。男39例,女13例;平均年龄38.8岁。选择纤维环后方出现高信号区的部分病例行腰椎后路椎间盘切除、椎体间融合、椎弓根螺钉内固定术,术中收集包括高信号区部位的椎间盘。对标本行矢状面连续组织学切片,光镜下观察高信号区椎间盘组织的组织病理学结构,并分析其临床意义。结果在行腰椎间盘造影的52例142个椎间盘中,17例17个椎间盘显示高信号区,且在椎间盘造影过程中全部呈现2或3级的纤维环破裂和疼痛复制反应。敏感性和特异性均为100%。高信号区与纤维环破裂程度分级呈正相关,说明纤维环破裂程度分级越高,越易出现高信号区(R=0.462,P<0.01)。共收集11例患者11个椎间盘,组织学研究发现对应高信号区的椎间盘组织表现为沿纤维环裂隙形成的不同程度的血管化肉芽组织,有成熟的瘢痕化胶原组织。结论症状性下腰痛患者的腰椎MRI上有椎间盘高信号区,可以作为椎间盘源性下腰痛诊断的重要征象。     

Histological development of intervertebral disc herniation

Sagittal and horizontal sections of 257 intervertebral discs obtained at autopsy and material obtained from 441 operations for herniation of a disc were examined histologically. In the material that was taken at autopsy, myxomatous degeneration of the annulus fibrosus increased in proportion to the age of the subject. The bundles in the internal layer of the annulus fibrosus reversed their usual direction and showed myxomatous degeneration, sometimes resulting in posterior and anterior convex bulging in the internal layer of the anterior and posterior parts of the annulus fibrosus, respectively. When material from a disc was surgically removed as a single free fragment (as in a complete extrusion or a sequestration type of herniation), annulus fibrosus with myxomatous degeneration was found in most material, while the nucleus pulposus rarely was. These results suggest that, from the standpoint of pathomechanism, a protrusion type of herniation of the annulus fibrosus exists in which only the annulus fibrosus is protruded due to reversal of the bundles of the annulus fibrosus, without involvement of the nucleus pulposus. This type of herniation would be a separate entity from the protrusion type of herniation of the nucleus pulposus that occurs when the nucleus pulposus is protruded through a fissure in the annulus fibrosus.     

Both expression of cytokines and posterior annulus fibrosus rupture are essential for pain behavior changes induced by degenerative intervertebral disc: An experimental study in rats

The aim of this study was to analyze the relationship between intervertebral disc degeneration and low back pain (LBP). Rat L4/5 disc degeneration model was established by annular puncture using a 0.4 mm needle anteriorly or posteriorly. In both anterior and posterior puncture models, magnetic resonance imaging (MRI) and histological analyses revealed marked disc degeneration 2 weeks after puncture. Cytokine expression was up‐regulated in different level in nucleus pulposus (NP) from 3 days after puncture. Pain behavioral tests indicated that the anterior disc puncture did not induce pain behavior changes, whereas the posterior disc puncture resulted in mechanical allodynia from 1 day to 21 days after injury. Besides, cytokine expression was significantly increased in dorsal root ganglion (DRG) at 1 and 2 weeks after posterior puncture, but not after the anterior puncture. These findings indicate the NP of the degenerative disc expresses different levels of inflammatory cytokines, and posterior disc puncture produced mechanical allodynia. The expression phase of cytokines in the NP was accordance with mechanical hyperalgesia in the posterior disc puncture model. Both expression of cytokines and posterior annulus fibrosus (AF) rupture in degenerative intervertebral disc are essential for pain behavior changes. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:262–272, 2014.     

MRI对腰椎纤维环后部破裂的诊断价值

目的明确腰椎MRI对诊断疼痛性纤维环破裂的敏感性。方法收集近 2年因腰椎间盘退变伴下肢放射痛而手术的患者47例,所有患者腰椎 MRI均有高信号区 (high-intensity zone, HIZ)表现。通过比较手术结果与 MRI影像学资料,对 MRI诊断纤维环后部破裂的敏感性作出评价。结果共研究 47例,手术探查 105个椎间盘。其中 HIZ椎间盘 56个,手术证实阳性率 85.7％,假阳性率 14.3％;无 HIZ椎间盘 49个,手术证实阴性率 87.8％,假阴性率 12.2％。结果表明 MRI诊断纤维环后部破裂的敏感性为 88.9％,特异性为 84.3％。结论 HIZ是诊断疼痛性腰椎纤维环后部破裂的特异性和敏感性较高的影像学标准。     

Bilateral PCL hypoplasia resulting in posterior, posterolateral rotatory instability and tears of the lateral meniscus anterior horn

This article describes a case of bilateral sagged knees presenting as posterior, posterolateral rotatory instability with tears of the anterior horn of the lateral meniscus. Each knee had identical tears of the lateral meniscus anterior horn. A 42-year-old woman reported bilateral anterior knee pain and painful instability during running or jarring exercises. She reported no major trauma to her knees. Arthroscopic findings of her right knee revealed a posterior cruciate ligament that looked hypoplastic but was without acute injury, and the anterior horn of the lateral meniscus showed chronic complex tears with some degeneration. Posterior cruciate ligament reconstruction, posterolateral corner sling, and meniscal repair of the lateral meniscus anterior horn was performed on her right knee. Three months later, a similar operation was performed on her left knee. However, menisectomy was performed because the lateral meniscus anterior horn tear was in the junction of the red-white and white zones. At 18 months postoperatively, the patient reported no symptoms and was satisfied with her results. Physical examination showed no joint line tenderness, and posterior stress radiographs on both knees showed grade I posterior instability. She showed no posterolateral subluxaion by supine dial test, and her prone dial test also improved approximately 15° on both knees. Lysholm score was 74 preoperatively and improved to 92 postoperatively.     

Surgical Treatment of Gluteus Medius Tears

The gluteus medius originates on the posterior face of the ilium between the posterior and anterior gluteal lines and inserts into the lateral and superoposterior facets of the greater trochanter. Because of the asymmetric nature of the muscle, tears are more likely to occur on the thinner anterolateral portion of the tendon footprint. Gluteus medius tears range from interstitial, partial thickness tears to retracted, full-thickness tears and may result from trauma, but they are more commonly the result of chronic degeneration. Patients commonly present with lateral hip pain aggravated by weight bearing and sleeping on the affected side, weakness in abduction, and the Trendelenburg sign observable on physical examination. Indications for surgery include failed conservative treatment and an ultrasound or magnetic resonance imaging study demonstrating a torn tendon. Surgical intervention aims to reapproximate and secure the torn tendon to the tendon footprint on the greater trochanter via suture anchors. Both open and endoscopic techniques have shown to be effective methods for treating gluteus medius tears at short- and long-term follow-up; however, endoscopic techniques have been shown to result in fewer postoperative complications, such as retear. A recent systematic review and meta-analysis found patients with more severe fatty infiltration (FI) may experience greater improvement after open repair, whereas patients with less severe FI may benefit more from endoscopic treatment. A double-row repair maximizes contact area between tendon and bone and has shown to be superior to single-row repair with an endoscopic technique.     

Stress in lumbar intervertebral discs during distraction: a cadaveric study

Background contextThe intervertebral disc is a common source of low back pain (LBP). Prospective studies suggest that treatments that intermittently distract the disc might be beneficial for chronic LBP. Although the potential exists for distraction therapies to affect the disc biomechanically, their effect on intradiscal stress is debated.PurposeTo determine if distraction alone, distraction combined with flexion, or distraction combined with extension can reduce nucleus pulposus pressure and posterior annulus compressive stress in cadaveric lumbar discs compared with simulated standing or lying.Study designLaboratory study using single cadaveric motion segments.Outcome measuresStrain gauge measures of nucleus pulposus pressure and compressive stress in the anterior and posterior annulus fibrosus.MethodsIntradiscal stress profilometry was performed on 15 motion segments during 5 simulated conditions: standing, lying, and 3 distracted conditions. Disc degeneration was graded by inspection from 1 (normal) to 4 (severe degeneration).ResultsAll distraction conditions markedly reduced nucleus pressure compared with either simulated standing or lying. There was no difference between distraction with flexion and distraction with extension in regard to posterior annulus compressive stress. Discs with little or no degeneration appeared to distribute compressive stress differently than those with moderate or severe degeneration.ConclusionsDistraction appears to predictably reduce nucleus pulposus pressure. The effect of distraction therapy on the distribution of compressive stress may be dependent in part on the health of the disc.     

高强度聚焦超声对离体兔腰椎间盘的生物学效应

目的观察不同剂量高强度聚焦超声对兔离体腰椎间盘的生物学效应。方法取6例剥离软组织的兔腰骶段脊柱标本（L1～S1）。将频率为9.6MHz、脉冲1 000Hz、剂量5W、焦距4mm的高强度聚焦超声从正前方聚焦于6例脊柱的L1S1椎间盘,各持续3、6、9、12、15、18min。此过程中,用热电偶针监测前方纤维环处与髓核交界处、HIFU焦点处、后方纤维环与髓核交界处、椎管内脊髓前表面的温度。结果 HIFU辐照过程中,监测点的温度逐渐升高,但升高的速度逐渐下降。HIFU在椎间盘前、后方纤维环处都能提供50℃以上的高温,并持续6min以上;焦点处能提供80℃以上的高温,并持续6min以上。结论高强度聚焦超声在椎间盘纤维环内可以提供足够高的温度,灭活纤维环内神经感受器可使髓核溶解、变性、萎缩,是治疗椎间盘源性腰痛的潜在方法。     

Tensile properties of the annulus fibrosus

Summary Part I of this study showed that collagen fibres do need not need to be continuous to reinforce the annulus fibrosus, and that 15-mm-wide samples of annulus retain about 44% of their in situ stiffness and strength when stretched vertically. Part II investigated the ultimate tensile strength (UTS) and fatigue life of such samples. Vertical slices, 5 mm thick and 30 mm wide, were cut from the anterior and posterior margins of the annulus and adjacent vertebral bodies. Each slice was divided sagittally to obtain a matched pair of specimens. The bony ends of each specimen were secured in a materials testing machine so that the annulus could be stretched vertically, as occurs during bending movements of the spine in life. One of each pair of specimens was stretched to failure to obtain its UTS; the other was cyclically loaded at some fraction of the UTS until failure occurred. Tensile failure started with the hyaline cartilage end-plate being stripped off the underlying bone and ended with the most peripheral annular fibres pulling out of the matrix. The estimated in situ strength in the vertical direction was 3.9 MPa for the anterior annulus and 8.6 MPa for the posterior annulus. Fatigue failure could occur in less than 10000 cycles if the tensile force exceeded 45% of the UTS. The results explain why radial fissures often fail to penetrate the peripheral annulus. When compared with in vivo measurements of spinal loading, they suggest that repetitive forward bending movements could cause fatigue failure of the posterior annulus.     

The pathogenesis and clinical significance of a high-intensity zone (HIZ) of lumbar intervertebral disc on MR imaging in the patient with discogenic low back pain

Recently, the presence of a high-intensity zone (HIZ) within the posterior annulus seen on T2-weighted MRI has aroused great interest and even controversy among many investigators, particularly on whether the HIZ was closely associated with a concordant pain response on awake discography. The study attempted to interpret the correlation between the presence of the HIZ on MRI and awake discography, as well as its characteristic pathology. Fifty two patients with low back pain without disc herniation underwent MRI and discography successively. Each disc with HIZ was correlated for an association between the presence of a HIZ and the grading of annular disruption and a concordant pain response. Eleven specimens of lumbar intervertebral discs which contain HIZ in the posterior annulus from 11 patients with discogenic low back pain were harvested for histologic examination to interpret the histologic basis of a nociceptive response during posterior lumbar interbody fusion (PLIF). The study found that in all of 142 discograms in 52 patients, 17 presented HIZ. All 17 discs with HIZ showed painful reproduction and abnormal morphology with annular tears extending either well into or through the outer third of the annulus fibrosus. The consecutive sagittal slices through the HIZ lesion showed that a notable histologic feature of the formation of vascularized granulation tissue in the outer region of the annulus fibrosus. The current study suggests that the HIZ of the lumbar disc on MRI in the patient with low back pain could be considered as a reliable marker of painful outer anular disruption.     

Mucoid Degeneration of Both ACL and PCL

Unlike meniscal tears and chondral defects, the mucoid degeneration of the anterior cruciate ligament (ACL) is a rare cause of knee pain and there have been no case reports of mucoid degeneration of both the ACL and the posterior cruciate ligament (PCL). A 48-year-old-male patient presented with knee pain and limitation of motion. The patient''s magnetic resonance imaging, arthroscopic findings, and pathologic diagnosis confirmed a clinical diagnosis of mucoid degeneration of both the ACL and the PCL. The symptoms disappeared after arthroscopic partial excision of the ACL and PCL.     

An observation of ruptured annulus fibrosus in lumbar discs.

To observe anatomical or pathological changes in lumbar intervertebral discs, discography and computed tomography-discography (CTD) were performed on fresh human cadavers. The results of discograms and CTD were compared with histological findings of cross sections of discs. Preoperative CTD of lumbar disc herniation was investigated based on these results. Ruptures of the annulus fibrosus were divided into two categories: circumferential rupture and radial rupture. In CTD images of fresh human cadavers, most images of rupture of the annulus fibrosus showed anterior to lateral circumferential rupture. As disc degeneration progressed, circumferential rupture tended to coexist with radial rupture in many cases. In CTD cases of lumbar disc herniation, most images of ruptures of the annulus fibrosus showed a posterior radial rupture, which was the route for herniated nucleus. The greater the degree of degeneration, the more the images tended to show radial ruptures coexisting with circumferential ruptures.     

Analysis of rabbit intervertebral disc physiology based on water metabolism. I. Factors influencing metabolism of the normal intervertebral discs

Basic factors influencing the metabolism of intervertebral discs of rabbits were quantitatively analyzed based on the water metabolism. The blood flow surrounding the intervertebral disc was calculated using pharmacokinetic concepts from the data obtained by time-related tritiated water distribution analyses. The blood flow was estimated as 0.056 (mg/min/mg tissue) in the anterior annulus, 0.106 in the posterior annulus, 0.120 in the lateral annulus, and 0.084 in the nucleus pulposus, respectively (Experiment 1). Water content and fixed charge density in the intervertebral disc fractions also were measured (Experiment 2). The cations and uncharged small solutes transported into the disc tissue ranged in descending order from nucleus pulposus, lateral annulus, posterior annulus, to anterior annulus. The authors also calculated theoretically the swelling pressure of the proteoglycan in the intervertebral disc fractions from the results of Experiment 2. It was concluded that swelling pressure was highest in the nucleus pulposus, and lowest in the anterior annulus. The water in the posterior annulus is less exchangeable than in the other disc tissue fractions.     

A clinicopathological study of cervical intervertebral discs--Part 1: On histopathological findings

In order to examine the aging process of the cervical intervertebral discs, a histopathological study was performed on 158 cervical discs obtained at autopsy from 37 individuals ranging in age from 3 months to 87 years. In the nucleus pulposus, degenerative changes consisting of myxomatous and slightly hyalinized degeneration were already seen in the specimens obtained from subjects in the third decade of life. Degenerative changes of the annulus fibrosus, however, tended to develop from the fourth decade of life, with myxomatous degeneration mainly in the anterior and hyalinized degeneration in the posterior annulus. The horizontal fissure of the annulus extending to its outer portion was seen more frequently in the posterior portion. In the cartilaginous plate of the vertebral body, fissure formation and degeneration became evident in the fifth decade of life. In contrast to the disc, repairing processes were observed in the cartilaginous plate. Spur formation at the corner of the vertebral body may be due to the degeneration of the outer layer of the disc leading to enchondral ossification.     

Editorial Commentary: Superior Labral Reconstruction for Superior Humeral Migration With Large or Massive Rotator Cuff Tears: Not a Paradigm Shift…Yet!

Large or massive rotator cuff tears are vexing clinical problems. Current treatment algorithms, while effective for many patients, are associated with failure of repair, persistent pain, and weakness including the inability to use the hand above shoulder level for some. Superior humeral migration associated with large or massive rotator cuff tears may lead to arthrosis or shoulder weakness. The biceps tendon has been reported for superior capsular reconstruction, but not often for reconstruction of the superior labrum. However, it is widely recognized the glenoid labrum plays a primary role in anterior and posterior shoulder instability. Therefore, degeneration of the superior labrum leading to superior humeral migration is plausible. Superior labral reconstruction merits exploration as a complementary procedure in addition to other procedures to center the humeral head in the glenoid.     

Mechanism of disc rupture. A preliminary report

Lumbar intervertebral disc herniation is thought to be related to senescent changes in the nucleus pulposus except in rare instances of trauma. This investigation provides the first in vitro model of disc prolapse that reliably ruptures discs under physiologically reasonable stress. Fourteen vertebral motion segments with intact posterior elements were loaded repetitively at 1.5 Hz in a combination of flexion (7 degrees), rotation (less than 3 degrees), and compression (1,334 N) for an average of 6.9 hours (range, 3.0-13.0 hours) in a materials testing machine. Loading was terminated when reaction force leveled off for more than 1 hour. Ten discs failed through annular protrusions, and four failed by nuclear extrusion through annular tears, supporting the hypothesis that intervertebral disc prolapse is peripheral in origin. The annulus fibrosus is the site of primary pathologic change.     

The pathogenesis of discogenic low back pain

Discogenic low back pain is a common cause of disability, but its pathogenesis is poorly understood. We collected 19 specimens of lumbar intervertebral discs from 17 patients with discogenic low back pain during posterior lumbar interbody fusion, 12 from physiologically ageing discs and ten from normal control discs. We investigated the histological features and assessed the immunoreactive activity of neurofilament (NF200) and neuropeptides such as substance P (SP) and vasoactive-intestinal peptide (VIP) in the nerve fibres. The distinct histological characteristic of the painful disc was the formation of a zone of vascularised granulation tissue from the nucleus pulposus to the outer part of the annulus fibrosus along the edges of the fissures. SP-, NF- and VIP-immunoreactive nerve fibres in the painful discs were more extensive than in the control discs. Growth of nerves deep into the annulus fibrosus and nucleus pulposus was observed mainly along the zone of granulation tissue in the painful discs. This suggests that the zone of granulation tissue with extensive innervation along the tears in the posterior part of the painful disc may be responsible for causing the pain of discography and of discogenic low back pain.     

Percutaneous endoscopic laser annuloplasty for discogenic low back pain

BackgroundLaser-assisted spinal endoscopy (LASE) kit has been used for percutaneous intradiscal decompression to evaporate and shrink the posterior and central nucleus for improvement of leg and radicular pain due to contained disc herniation. Percutaneous endoscopic laser annuloplasty (PELA), a new minimally invasive technique, uses LASE to directly coagulate the inflamed disc granulation tissue associated with annular tears. The small diameter of the endoscope including Ho:YAG laser, irrigation, and light, plus the extreme posterolateral approach into the posterior annulus, enables one to minimize damage to normal nuclear tissue. The authors sought to demonstrate the safety and efficacy of PELA for controlling discogenic low back pain (DLBP) due to abnormal disc tissues, new vessels, and nerves in the central torn posterior annulus.MethodsClinical outcomes of PELA were investigated in patients having DLBP with an annulus-torn degenerative disc or contained disc herniation. Thirty patients treated at a single level and achieving a mean follow-up of 9.7 months were analyzed. Outcomes were assessed using the visual analog scale (VAS) for back pain, the Korean Oswestry Disability Index (KODI), and the modified Macnab's criteria.ResultsThe mean back pain VAS score improved from 8.0 to 2.4, and the mean KODI score improved from 79.0 to 22.4 (P < .001). Results by the modified Macnab's criteria also showed a good outcome, with a success rate of 90.0%. There were no serious complications observed during follow-up.ConclusionsPercutaneous endoscopic laser annuloplasty using the Ho:YAG laser provides favorable outcomes for carefully selected groups of patients with DLBP.