Loss Of Disc Height Research Articles

Radiographic and clinical evaluation of cage subsidence after stand-alone lateral interbody fusion

Indirect decompression of the neural structures through interbody distraction and fusion in the lumbar spine is feasible, but cage subsidence may limit maintenance of the initial decompression. The influence of interbody cage size on subsidence and symptoms in minimally invasive lateral interbody fusion is heretofore unreported. The authors report the rate of cage subsidence after lateral interbody fusion, examine the clinical effects, and present a subsidence classification scale. The study was performed as an institutional review board-approved prospective, nonrandomized, comparative, single-center radiographic and clinical evaluation. Stand-alone short-segment (1- or 2-level) lateral lumbar interbody fusion was investigated with 12 months of postoperative follow-up. Two groups were compared. Forty-six patients underwent treatment at 61 lumbar levels with standard interbody cages (18 mm anterior/posterior dimension), and 28 patients underwent treatment at 37 lumbar levels with wide cages (22 mm). Standing lateral radiographs were used to measure segmental lumbar lordosis, disc height, and rate of subsidence. Subsidence was classified using the following scale: Grade 0, 0%-24% loss of postoperative disc height; Grade I, 25%-49%; Grade II, 50%-74%; and Grade III, 75%-100%. Fusion status was assessed on CT scanning, and pain and disability were assessed using the visual analog scale and Oswestry Disability Index. Complications and reoperations were recorded. Pain and disability improved similarly in both groups. While significant gains in segmental lumbar lordosis and disc height were observed overall, the standard group experienced less improvement due to the higher rate of interbody graft subsidence. A difference in the rate of subsidence between the groups was evident at 6 weeks (p = 0.027), 3 months (p = 0.042), and 12 months (p = 0.047). At 12 months, 70% in the standard group and 89% in the wide group had Grade 0 or I subsidence, and 30% in the standard group and 11% in wide group had Grade II or III subsidence. Subsidence was detected early (6 weeks), at which point it was correlated with transient clinical worsening, although progression of subsidence was not observed after the 6-week time point. Moreover, subsidence occurred predominantly (68%) in the inferior endplate. Fusion rate was not affected by cage dimension (p > 0.999) or by incidence of subsidence (p = 0.383). Wider cages avoid subsidence and better restore segmental lordosis in stand-alone lateral interbody fusion. Cage subsidence is identified early in follow-up and can be accessed using the proposed classification scale.

Not just simple degenerative disc disease (alkaptonuria)

A 54-year-old man presented with a 15-year history of progressive back pain. On physical examination, a grayish pigmentation of the sclera and to his ear cartliage was noted. Spinal movements were restricted. Radiography of the lumbar spine revealed calcification of the intervertebral discs and severe degenerative change (Fig. 1). Magnetic resonance imaging of the lumbar spine revealed loss of intervertebral disc height and low signal within the intervertebral discs on T1- and T2-weighted sequences (Fig. 2).

Injection of human umbilical tissue–derived cells into the nucleus pulposus alters the course of intervertebral disc degeneration in vivo

Background contextPatients often present to spine clinic with evidence of intervertebral disc degeneration (IDD). If conservative management fails, a safe and effective injection directly into the disc might be preferable to the risks and morbidity of surgery. PurposeTo determine whether injecting human umbilical tissue–derived cells (hUTC) into the nucleus pulposus (NP) might improve the course of IDD. DesignProspective, randomized, blinded placebo–controlled in vivo study. Patient sampleSkeletally mature New Zealand white rabbits. Outcome measuresDegree of IDD based on magnetic resonance imaging (MRI), biomechanics, and histology. MethodsThirty skeletally mature New Zealand white rabbits were used in a previously validated rabbit annulotomy model for IDD. Discs L2–L3, L3–L4, and L4–L5 were surgically exposed and punctured to induce degeneration and then 3 weeks later the same discs were injected with hUTC with or without a hydrogel carrier. Serial MRIs obtained at 0, 3, 6, and 12 weeks were analyzed for evidence of degeneration qualitatively and quantitatively via NP area and MRI Index. The rabbits were sacrificed at 12 weeks and discs L4–L5 were analyzed histologically. The L3–L4 discs were fixed to a robotic arm and subjected to uniaxial compression, and viscoelastic displacement curves were generated. ResultsQualitatively, the MRIs demonstrated no evidence of degeneration in the control group over the course of 12 weeks. The punctured group yielded MRIs with the evidence of disc height loss and darkening, suggestive of degeneration. The three treatment groups (cells alone, carrier alone, or cells+carrier) generated MRIs with less qualitative evidence of degeneration than the punctured group. MRI Index and area for the cell and the cell+carrier groups were significantly distinct from the punctured group at 12 weeks. The carrier group generated MRI data that fell between control and punctured values but failed to reach a statistically significant difference from the punctured values. There were no statistically significant MRI differences among the three treatment groups. The treated groups also demonstrated viscoelastic properties that were distinct from the control and punctured values, with the cell curve more similar to the punctured curve and the carrier curve and carrier+cells curve more similar to the control curve (although no creep differences achieved statistical significance). There was some histological evidence of improved cellularity and disc architecture in the treated discs compared with the punctured discs. ConclusionsTreatment of degenerating rabbit intervertebral discs with hUTC in a hydrogel carrier solution might help restore the MRI, histological, and biomechanical properties toward those of nondegenerated controls. Treatment with cells in saline or a hydrogel carrier devoid of cells also might help restore some imaging, architectural, and physical properties to the degenerating disc. These data support the potential use of therapeutic cells in the treatment of disc degeneration.

DYNAMIC RESPONSES OF INTERVERTEBRAL DISC DURING STATIC CREEP AND DYNAMIC CYCLIC LOADING: A PARAMETRIC POROELASTIC FINITE ELEMENT ANALYSIS

Low back pain is a common reason for activity limitation in people younger than 45 years old, and was proved to be associated with heavy physical works, repetitive lifting, impact, stationary work postures and vibrations. The study of load transferring and the loading condition encountered in spinal column can be simulated by finite element models. The intervertebral disc is a structure composed of a porous material. Many physical models were developed to simulate this phenomenon. The confounding effects of poroelastic properties and loading conditions on disc mechanical responses are, nevertheless, not cleared yet. The objective of this study was to develop an axisymmetric poroelastic finite element model of intervertebral disc and use it to investigate the confounding effect of material properties and loading conditions on the disc deformation and pore pressure. An axisymmetric poroelastic model of human lumbar L4–L5 motion segment was developed. The model was validated by comparing the height loss and intradiscal pressure of the L4–L5 intervertebral disc with in vitro cadaveric studies. The effect of permeability, void ratio, elastic modulus, and Poisson's ratio on disc height and pore pressure was investigated for the following three loading conditions: (1) 1334 N creep loading, (2) peak-to-peak, 1000-to-1600 N, 1 Hz cyclic loading, and (3) same loading magnitude, but at 5 Hz loading frequency. The disc height loss and pore pressure of the three loading conditions were analyzed. The predictions of the disc height loss and intradiscal pressure of the current FE model are well comparable with the results of in vitro cadaveric studies. After model validation, the parametric study of disc poroelastic properties on the disc mechanical responses shows that the increase of permeability and void ratio increases the disc height loss and decreases the pore pressure, and these effects are sensitive to external loading frequency. Higher elastic modulus reduces the disc deformation and the pore pressure, but this reduction is not sensitive to the loading frequency. The effect of Poisson's ratio on disc height loss and pore pressure is negligible. In conclusion, the hydraulic permeability describes the fluid flow capability within tissue matrix which has a higher sensitivity on the saturation time for disc deformation and pore pressure. Void ratio directly affects the amount of mobile water within disc and changes time-dependent response of disc. Increase in loading frequency reduces time for fluid inflow and outflow, which fades out the role of permeability and void ratio. Values of elastic modulus and Poisson's ratio, which demonstrates stiffness and bulging capacity, respectively, do not affect the overall dynamic response of disc.

Discogenic Axial Back Pain: Is There a Role for Nucleoplasty?

Study DesignA prospective observational study.PurposeTo evaluate the role of nucleoplasty in the management of discogenic axial back pain; to determine the influence of concordant pain during provocative discography, annular tear and loss of disc height on the outcome of nucleoplasty.Overview of LiteratureThe role of nucleoplasty in the management of radicular leg pain due to disc herniation is known. However, the data regarding its role in the management of discogenic axial back pain is scarce.MethodsA prospective evaluation of 30 patients with discogenic axial back pain undergoing nucleoplasty was performed. Pain, functional disability and quality of life were assessed using the 100 mm visual analogue scale (VAS), Oswestry Disability Index (ODI) and Short Form-36 (SF-36), respectively.ResultsThe mean reduction in VAS was 31.03 and 29.03; mean reduction in ODI was 24.53 and 20.60; and mean increment in SF-36 was 13.58 and 12.30, at 6 months and at 12 months, respectively. The differences were statistically significant (p <0.05). Concordant pain during provocative discography, annular tear and loss of disc height did not affect a clinically significant improvement in any of the three outcomes (p =0.882, 0.213, and 0.170; respectively).ConclusionsNucleoplasty produced statistically significant improvements in pain, functional disability and quality of life in patients with discogenic low back pain at 6 months and at 12 months. Concordant pain during provocative discography, annular tear and loss of disc height did not influence any of the outcomes after nucleoplasty in patients with discogenic axial back pain.

Normalized intervertebral disc MRI signal as a biomarker of pain

The drop in the MRI signal intensity, analysed without any normalisation, was found related to the intervertebral disc degeneration, but its association with low back pain remains controversial. The authors developed the analysis of MR signal intensity distribution (AMRSID) method that analyzes the 3D distribution of the normalized T2-weighted MR signal intensity within the intervertebral disc using descriptive statistics of histograms and weighted centers. In this study, we hypothesized that the distribution of the normalized MRI signal intensity within T2- weighted images of the intervertebral disc is a bio-marker of low back pain (LBP) independently of age and disc degenerescence. The aims were to: 1) characterize intervertebral disc degeneration in vertebral fracture from MR T1-weighted and T2-weighted images; 2) evaluate the sensitivity of the normalized MRI signal distribution to the presence of LBP, discs height loss and aging. We prospectively studied 22 patients who underwent an MRI acquisition within 48h after an accidental lumbar vertebral fracture. The presence of prefracture low back pain, spinal stenosis, annular disruption, intervertebral disc height loss was noted from each patient’s medical record. The presence of Modic changes, High-Intensity Zones (HIZs) and vertebral endplate perforations was recorded from MRI. The descriptive statistics of the normalized T2-weighted signal were compared using one-way ANOVAs and a principal component analysis was proposed. MRI, associated to normalisation of the signal intensity and principal component analysis, offers a remarkable potential for in-vivo imaging and analysis of vertebral fractures and adjacent tissues for the patient’s follow-up. The mean normalized MRI signal intensity of the adjacent intervertebral disc to the vertebral fracture was found to be a bio-marker of pain, independently of age and disc degeneration. However, the parameters describing the distribution of the normalized signal intensity were found to be not sensitive to the presence of low back pain, discs height loss and aging. Further studies need to be performed to detect small abnormalities that may explain the presence of LBP.

Diagnosis and Treatment of Fusobacterium Nucleatum Discitis and Vertebral Osteomyelitis

Case report. We present a case of vertebral osteomyelitis and discitis caused by Fusobacterium nucleatum in a 42-year-old female. Infection of the vertebral bodies or disc space with this organism is rare. A review of the English literature disclosed 13 cases of vertebral osteomyelitis caused by Fusobacterium spp. Because of the negative impact of this condition on the affected patients' activities of daily living, it is important to understand the clinical character and effective management of the disease to improve quality of life. Fusobacterium is an anaerobic and gram-negative microbe that is part of the normal flora of the mouth, gastrointestinal tract, and female genital tract. It is the main cause of Lemierre syndrome and has also been seen in septicemia. The patient presented to our institution with a 3-month history of severe lower back pain. Her back pain was diagnosed as vertebral osteomyelitis. Magnetic resonance images of the lumbar spine revealed decreased T2 signal in the L3 and L4 vertebral bodies. Computed tomographic scan demonstrated asymmetrical disc height loss between vertebral bodies L3 and L4 and associated periosteal reaction. Computed tomography-guided biopsy of vertebral bodies L3 and L4 revealed microorganism Fusobacterium nucleatum with the following in vitro susceptibilities: clindamycin ≤0.5 S, metronidazole ≤0.5 S, penicillin ≤0.5 S, ertapenem ≤4 S. Parenteral ertapenem, at a dose of 1 g every 24 hours for 8 weeks in combination with oral amoxicillin and clavulanate as oral suppression was used as medical management. At 1-month follow-up after medical treatment, the patient's inflammatory markers returned to normal values, and the infection resolved with L3-L4 autofusion. We report a rare case of Fusobacterium vertebral osteomyelitis. This condition is associated with several comorbid and concomitant conditions including gastrointestinal complications. Effective treatment includes thoracolumbar orthosis bracing and intravenous antibiotic therapy.

Intervertebral disc as a source of pain

Back pain, although not usually life threatening, is a major public health problem both here in the UK and in Western societies in general. It affects a large number of people each year and is a cause of considerable economic loss and personal suffering. Point prevalence rates indicate that it affects between 12% and 35% of the population, of whom 20% will seek medical attention. One study in the UK estimated that in 1998, direct health-care costs associated with back pain were approximately £1.6 billion, but the total costs related to lost productivity closer to £11 billion. 2 A number of anatomical structures within the back may be responsible for back pain; intervertebral discs, facet joints, muscles, ligaments, and nerve root sheaths are all possible ‘pain generators’. Of these, the intervertebral discs, facet joints, and sacroiliac joints are implicated in up to 45, 40, and 13% of the cases, respectively. Furthermore, more than one structure may be contributing to the pain at any one time. The intervertebral disc may produce pain either as a result of intrinsic degeneration (discogenic pain) or by extrinsic compression of neural structures in the spinal canal, producing radicular pain. Disc degeneration also results in loss of disc height which, in turn, may alter the mechanics of the axial skeleton. These changes may produce pain in other structures including the zygapophyseal (facet) joints and may ultimately result in spinal stenosis. Discogenic pain is defined as axial pain originating in a degenerative disc. Radicular pain is the pain radiating in the distribution of a spinal nerve caused by the irritation of the sensory root or dorsal root ganglion (DRG) of that spinal nerve.Although degenerative disc disease (DDD) is the most common cause of such compression, there are other pathologies which may produce radicular pain.

Posterior dynamic stabilization in the treatment of degenerative lumbar stenosis: validity of its rationale

The authors undertook this study to investigate the validity of the rationale for posterior dynamic stabilization using the Device for Intervertebral Assisted Motion (DIAM) in the treatment of degenerative lumbar stenosis. A cohort of 31 patients who underwent single-level decompression and DIAM placement for degenerative lumbar stenosis were followed up for at least 2 years and data pertaining to their cases were analyzed prospectively. Of these patients, 7 had retrolisthesis. Preoperative and postoperative plain lumbar radiographs obtained in all patients and CT images obtained in 14 patients were analyzed. Posterior disc heights; range of motion (ROM) of proximal, distal, and implant segments; lordotic angles of implant segments; percentage of retrolisthesis; and cross-sectional area and heights of intervertebral foramina on CT sagittal images were analyzed. Clinical outcomes were evaluated using visual analog scale scores and Oswestry Disability Index scores. The mean values for posterior disc height before surgery, at 1 week after surgery, and at the final follow-up visits were 6.4 ± 2.0 mm, 9.7 ± 2.8 mm, and 6.8 ± 2.5 mm, respectively. The mean lordotic angles at the implant levels before surgery, at 1 week after surgery, and at the final follow-up visits were 7.1° ± 3.3°, 4.1° ± 2.7°, and 7.0° ± 3.7°, respectively. No statistically significant difference was found between the preoperative values and values from final follow-up visits for posterior disc height and lordotic angles at implant levels (p = 0.17 and p = 0.10, respectively). There was no statistically significant difference between the preoperative and final follow-up visit values for intervertebral foramen cross-sectional area and heights on CT images. The ROMs of proximal and distal segments also showed no significant decrease (p = 0.98 and p = 0.92, respectively). However, the ROMs of implant segments decreased significantly (p = 0.02). The average 31.4-month improvement for all clinical outcome measures was significant (p < 0.001). Based on radiological findings, the DIAM failed to show validity in terms of the rationale of indirect decompression, but it did restrict motion at the instrumented level without significant change in adjacent-segment ROM. The clinical condition of the patients, however, was improved, and improvement was maintained despite progressive loss of posterior disc height after surgery.

Five-year adjacent-level degenerative changes in patients with single-level disease treated using lumbar total disc replacement with ProDisc-L versus circumferential fusion

The authors report the 5-year results for radiographically demonstrated adjacent-level degenerative changes from a prospective multicenter study in which patients were randomized to either total disc replacement (TDR) or circumferential fusion for single-level lumbar degenerative disc disease (DDD). Two hundred thirty-six patients with single-level lumbar DDD were enrolled and randomly assigned to 2 treatment groups: 161 patients in the TDR group were treated using the ProDisc-L (Synthes Spine, Inc.), and 75 patients were treated with circumferential fusion. Radiographic follow-up data 5 years after treatment were available for 123 TDR patients and 43 fusion patients. To characterize adjacent-level degeneration (ALD), radiologists at an independent facility read the radiographic films. Adjacent-level degeneration was characterized by a composite score including disc height loss, endplate sclerosis, osteophytes, and spondylolisthesis. At 5 years, changes in ALD (ΔALDs) compared with the preoperative assessment were reported. Changes in ALD at 5 years were observed in 9.2% of TDR patients and 28.6% of fusion patients (p = 0.004). Among the patients without adjacent-level disease preoperatively, new findings of ALD at 5 years posttreatment were apparent in only 6.7% of TDR patients and 23.8% of fusion patients (p = 0.008). Adjacent-level surgery leading to secondary surgery was reported for 1.9% of TDR patients and 4.0% of fusion patients (p = 0.6819). The TDR patients had a mean preoperative index-level range of motion ([ROM] of 7.3°) that decreased slightly (to 6.0°) at 5 years after treatment (p = 0.0198). Neither treatment group had significant changes in either ROM or translation at the superior adjacent level at 5 years posttreatment compared with baseline. At 5 years after the index surgery, ProDisc-L maintained ROM and was associated with a significantly lower rate of ΔALDs than in the patients treated with circumferential fusion. In fact, the fusion patients were greater than 3 times more likely to experience ΔALDs than were the TDR patients. Clinical trial registration no.: NCT00295009.

MR-based outcome predictors of lumbar transforaminal epidural steroid injection for lumbar radiculopathy caused by herniated intervertebral disc

To evaluate the MR-based outcome predictors of lumbar transforaminal epidural steroid injection (ESI) for lumbar radiculopathy caused by herniated intervertebral disc (HIVD). A total of 149 patients (male/female 75:74; mean age 51.5 years) with the very worst (87 patients) or the very best outcome (62 patients) after ESI were enrolled in this study. They were selected from 1,881 patients who underwent lumbar transforaminal ESI for lumbar radiculopathy caused by HIVD from January 2007 to December 2008. Two radiologists reviewed MR in consensus. Chi-square test and Fisher's exact test were used to evaluate the difference between the two groups. HIVD in the foraminal-extraforaminal zone were significantly more common in the very best outcome group (16/24, 66.6 %) than HIVD in the central-subarticular zone (46/125, 36.8 %) (P = 0.012). Other factors such as HIVD zone, T2-high signal, relation to nerve root, corner change, Modic change, disc height loss, grade of disc degeneration, and osteophyte were not statistically significant. HIVD in the foraminal or extraforaminal zone is the only good MR-based outcome predictor of lumbar transforamial ESI for lumbar radiculopathy.

Infections of the spinal column – Spondylodiscitis

Infectious spondylodiscitis is an infection of the intervertebral disc and the adjacent vertebral bodies due to the introduction of a pyogen, usually by the haematogenous route. Plain film radiography (which is usually normal in the early stages) shows blurring of the vertebral endplates and a loss of disc height that progresses quickly. MRI is the examination of choice, as it detects oedema within the trabecular bone very early, before the onset of destruction. Injection of a contrast medium with fat signal saturation improves detection and visualisation of the spread of infection in the soft tissue and epidural space. Imaging can also be used to guide a needle aspiration to investigate the infective agent.

“Dynamic Fusion” in Degenerative Lumbar Spine Disorders

Introduction Dynamic stabilization in lumbar degenerative disorders has become very popular in the last few years. The basic concept of pedicle-screw-based systems is to reduce stiffness of the implants to allow load sharing between instrumentation system and functional spine (movement) unit to prevent adjacent segment syndrome. Basic biomechanical requirements for this philosophy are as follows: (a) a predicable load distribution to the intervertebral disk, (b) the limitation (control) of range of motion, and (c) to maintain and/or to restore the sagittal (sacral) balance. Disk degeneration results in loss of disk height and increase of axial compression loading in the posterior spine elements, probably accompanied with accelerated facet degeneration (arthrosis). Challenged by G. Perrinás reports in the late 1990s we started in 2002 with dynamic (semirigid) transpedicular stabilization systems in degenerative lumbar spine disorders using Isolock device, later using Isobar and AladynR device also. Materials and Methods This paper presents an inhomogene case presentation of 26 patients with different perception of degenerative lumbar disorders. Patients underwent a so called “Dynamic Fusion” between 2003 and 2007 using PLIF or TLIF added by posterior transpedicular dynamic (semirigid) stabilization. The case presentation presents preoperative, postoperative radiographs, and maximally follow-up radiographs to show a perfect bony healing in anterior elements. Definition of Dynamic Fusion Semirigid pedicle screw systems allow an increased anterior column load-sharing leading to favor osteogenesis with enhanced interbody fusion. This physical phenomenon is related to Wolffás Law. Lavaste and Perrin validated in 1993 in a finite element model of the lumbar spine that semirigid posterior instrumentation increases compared to rigid instrumentation of the load transmission through the anterior column. This observation and the publication by Goel et al confirmed that dynamic stabilization systems enable more load through the anterior column and the interbody graft compared to rigid systems without compromising stability, led to changing philosophy. We started to combine PLIF/TLIF with posterior transpedicular semirigid stabilization over the instrumented segment. Results No loosening signs of the PLIF/TLIF implants have been followed-up in this patient cohort. The evaluated pain relief is depended on many factors but all patients had a pain level degree in the VAS (25%). Conclusion The PLIF/TLIF in degenerative lumbar spine disorders showed in combination with posterior semirigid stabilization good clinical and radiographical results. No implant loosening has been followed up. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared Perrin G: Treatment of lumbar spondylolisthesis and related unstable spinal lesions: the usefulness of PLIF with cages and dynamic interpedicular posterior fixation for circumferential arthrodesis and prevention of adjacent level degeneration. presented at the 3rd World Spine Meeting, Rio de Janeiro, 2005 Goel VK, Lim Th, Gwon J, et al. Effects of rigidity of an internal fixation device. A comprehensive biomechanical investigation. Spine 1991;16:155–161

A Non-Fusion Technique for Removal of Cervical Disk Prolapse using Minimally Invasive Anterior Cervical Transoseous Approach

Introduction In Acute cervical disk prolapse, root compression is the source of pain. In all established techniques, the removal of cervical disk prolapse is performed either through the disk space or through the foramen or joint (microforaminotomy, Frykholm's procedure). So as a result of these techniques, either bradytrophic tissue with little healing potential is disturbed, or bone structures involved in weight bearing or movement are partiallly resected. Consequently, most of these decompression procedures have to be combined with fusion or disk replacement. Materials and Methods This prospective study included P114 patients (54 females and 46 males) with a mean age of 46.4 years and was operated from 2005 to 2010. Indications were cervical soft disk herniations causing symptomatic root compression. Contraindications included instability of the affected segment, central spine compression, fractures or advanced degeneration. A modified version of Oswestry index and the neck disability index (NDI) for neck and arm pain was recorded preoperatively as well as, 3 m and 1 year postoperatively. Also the visual analog scale (VAS) was recorded before and after the procedure. The approach via a 15 mm skin incision is performed by removing a bone cylinder of 6 mm in diameter from the cranial vertebra temporarily. The sequester is removed under direct visual control of the operating microscope. After decompression the bone cylinder is repositioned. Results The mean operation time per 1 segment was 64.4 minutes and mean blood loss was 82.04 mL. Hospitalization period ranged from 2 to 3 days and patients were mobilized in the same day of operation. Total 98 (98%) patients showed complete recovery of neurological deficits postoperatively. The postoperative mean NDI was improved from 34 (preoperative) to 4.6 (postoperative). Also the mean Oswestry score was improved from 16.4 to 1.6. Corresponding improvement of the VAS for neck and arm pain was also recorded and was improved from 6 to 1.3. All 3 scores were statistically significant ( p = 0.05). The 1-year postoperative functional radiographic assessment showed that there was no significant impairment of the stability of the operated segment according to the criteria of White and Panjabi. Complications: one patient (2%) suffered from recurrence after 4 weeks, that was resolved after reoperation with the same method. There was no dural or root sleeve injury. There was no neurological dificit. Neither an approach related postoperative problem nor an infection did occur. Conclusion Removal of a lateral or foraminal disk prolapse through a bony channel proved to be possible and safe. Since the bone cylinder is put back in situ and proved to be incorporated in the vertebral body there is no permanent lesion of the approach. Short-term reduction of the corpus mechanical strength did not lead to any adverse side effect. Since no significant loss of disk height, kyphosis, or segmental instability did occur, this minimal invasive procedure may be a valuable additional option in the operative treatment of the cervical disk prolapse. I confirm having declared any potential conflict of interest for all authors listed on this abstract No Disclosure of Interest None declared Böhm H, Greiner-Perth R, et al. A new minimally invasive posterior approach for the treatment of cervical radiculopathy and myelopathy. Surgical technique and preliminary results. European Spine Journal 2003;12:268–273 Brunaeu M, Cornelius Jf, George B., et al. Microsurgical cervical nerve root decompression by anterolateral approach. Operative Neurosurgery 2006;2:108–113 Cloward RB: The anterior approach for removal of ruptured cervical discs. Journal of Neurosurgery 1958;15:602–617 Fontanella A. Endoscopy microsurgery in herniated cervical discs. Int Intradiscal Therapy Soc Inc Tenth Ann Meet, Naples, Florida, 1997 (Neurological Research 01 (1999) 21:31–38) Fontanella A. Minimally invasive neurosurgery. A convincing alternative to open surgery. Rivista di Neuroradiologia 1997; 10:541 Fritsch EW, Pitzen T. Zervikale Bandscheibenprothesen. Der Orthopäde 3 2006;35:347–361 Heidecke V., Vogel S., Beurkert W. et al. Ergebnisse nach ventraler Fusion mittels Carbon-bzw. Titancage bei zervikalen Bandscheibenvorfällen. Dissertation zur Erlangung des akademischen Grades Doktor der Medizin. (2004) Hilton L. Minimally invasive tubular access for posterior cervical foraminotomy with three dimensional microscopic visualizationand localization with anterior/posterior imaging. The Spine Journal 2007;7:154–158

Intervertebral Disk Degeneration in the Growing Spine in Patients with Tuberculosis Kyphosis Exceeding 50 Treated by Reconstruction with a Long-Length Posterior Instrumentation

Introduction The rigid angular kyphoses in the young patients with spinal TB are not only a cosmetic problem, they also lead to cardiovascular, respiratory, and neurological disorders. The correction of the deformity could be reached by combination of the debridement, anterior column reconstruction, the shortening of posterior spine, and extended posterior instrumentation. The zone of instrumentation needs to be longer than the anterior fusion for significant correction and spinal stability. Materials and Methods Total 13 children from 2.5 to 12 years with TB spondylitis of the thoracic and lumbar spine complicated by severe angular kyphosis underwent 1-day combined surgery included anterior debridement followed by cortical bone allografting and posterior osteotomy with correction and instrumentation by laminar or hybrid devises. The anterior reconstruction exceeded three segments in all cases (maximum-replacement of 10 vertebral bodies). For real deformity correction the posterior instrumented zone exceeded the length of anterior reconstruction up to 1 or 3 segments cephalad and caudad. The operations were performed under the SSEP monitoring and additionally with wake-up test-in older cases. Neither neurological nor inflammatory complications were in these patients. The normal or closed to the normal sagittal profile was reached in all cases. Follow-up period ranged from 2 till 13 years. Complete follow-up: 13 cases. All patients have annual X-ray control. There wasn't any signs of anterior pseudo-arthrosis revealed. The condition of subchondral vertebral plates and the height of intact intervertebral disks within the zone of instrumentation and disks adjacent to the instrumented spine were compared. Results Total 11 of 13 operated patients (85%) demonstrated degeneration of initially intact disks within the instrumented spine 2 years after the surgery. The signs included loss of disk height, sclerosis, and deformation of subchondral vertebral plates. Despite nobody had back pain, the main parents' complaint was the limitation of spine range of motion. We've decided to count the early symptoms of disk degeneration, the indication to remove spinal hardware having solid anterior fusion documented. There was no increase of kyphosis, excluding one case of conjunctive deformity above the instrumented spine. Conclusion The intervertebral disks degeneration within the instrumented zone is a typical side effect of prolonged posterior rigid instrumentation in growing spine. After 2 years of surgery, it occurred in a majority of pediatric patients who had been operated due to the thoracic and lumbar spinal TB complicated by kyphosis exceeded 50ø. This degeneration was not accompanied by the pain during the childhood, but it may become symptomatic in adulthood. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared

Vertebral Bone Remodeling after Disk Degeneration-Quantitative Microanalysis in a Porcine Nucleotomy Model

Introduction Changes in vertebral endplate sclerosis and permeability seem to be a crucial aspect in the course of disk degeneration. Detailed information on microstructural changes of the subchondral bone of the endplates and the trabecular vertebral bone is missing, especially when bony remodeling runs parallel with disk remodeling or not. Therefore, the goal of this study was to analyze this in an established disk degeneration model on minipigs. Materials and Methods Animals were divided into three groups. Group 1 and 2 received partial nucleotomy with a 16G-biopsy-cannula to induce moderate disk degeneration and were followed for 13 and 24 weeks, respectively. Group 3 did not receive surgery and served as controls. A total of 24 disks and 48 endplates with subchondral bone and trabecular vertebral bone were analyzed histologically and by quantitative micro-CT. Standardized elliptical volumes of interest were analyzed by Skyscan-micro-CT-software. Results Both group 1 and 2 showed disk degeneration with significant loss of disk height, higher disk- and endplate-degeneration-scores, fibrous scarring, and loss of notochordal cells ( p &lt; 0.05 compared to controls). Micro-CT revealed less sclerosis (BV/TV) and reduced trabecular thickness of subchondral bone underneath the endplates 13 weeks after nucleotomy compared to untreated controls ( p &lt; 0.05 group 1 vs. group 2 and 3); after 24 weeks, however, values turned back to those of controls again. The same correlation was found in more distant trabecular vertebral bone, though BV/TV values were lower. Separate analysis of changes above and below the operated disk did not show differences. Conclusion Contrary to the concept of simultaneous bony endplate sclerosis and disk degeneration, we found reduced BV/TV and trabecular thickness early after nucleotomy induced disk degeneration. At later stages of disk degeneration, sclerosis was not higher than in healthy controls, indicating that disk degeneration can proceed independently from endplate sclerosis. The vertebral bone is highly reactive to disk disturbances but does not automatically react with increased sclerosis. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared

A Non-Fusion Technique for Removal of Cervical Disk Prolapse using Minimally Invasive Anterior Cervical Transoseous Approach

IntroductionIn Acute cervical disk prolapse, root compression is the source of pain. In all established techniques, the removal of cervical disk prolapse is performed either through the disk space or through the foramen or joint (microforaminotomy, Frykholm's procedure). So as a result of these techniques, either bradytrophic tissue with little healing potential is disturbed, or bone structures involved in weight bearing or movement are partiallly resected. Consequently, most of these decompression procedures have to be combined with fusion or disk replacement.Materials and MethodsThis prospective study included P114 patients (54 females and 46 males) with a mean age of 46.4 years and was operated from 2005 to 2010. Indications were cervical soft disk herniations causing symptomatic root compression. Contraindications included instability of the affected segment, central spine compression, fractures or advanced degeneration. A modified version of Oswestry index and the neck disability index (NDI) for neck and arm pain was recorded preoperatively as well as, 3 m and 1 year postoperatively. Also the visual analog scale (VAS) was recorded before and after the procedure. The approach via a 15 mm skin incision is performed by removing a bone cylinder of 6 mm in diameter from the cranial vertebra temporarily. The sequester is removed under direct visual control of the operating microscope. After decompression the bone cylinder is repositioned.ResultsThe mean operation time per 1 segment was 64.4 minutes and mean blood loss was 82.04 mL. Hospitalization period ranged from 2 to 3 days and patients were mobilized in the same day of operation. Total 98 (98%) patients showed complete recovery of neurological deficits postoperatively. The postoperative mean NDI was improved from 34 (preoperative) to 4.6 (postoperative). Also the mean Oswestry score was improved from 16.4 to 1.6. Corresponding improvement of the VAS for neck and arm pain was also recorded and was improved from 6 to 1.3. All 3 scores were statistically significant (p = 0.05). The 1-year postoperative functional radiographic assessment showed that there was no significant impairment of the stability of the operated segment according to the criteria of White and Panjabi. Complications: one patient (2%) suffered from recurrence after 4 weeks, that was resolved after reoperation with the same method. There was no dural or root sleeve injury. There was no neurological dificit. Neither an approach related postoperative problem nor an infection did occur.ConclusionRemoval of a lateral or foraminal disk prolapse through a bony channel proved to be possible and safe. Since the bone cylinder is put back in situ and proved to be incorporated in the vertebral body there is no permanent lesion of the approach. Short-term reduction of the corpus mechanical strength did not lead to any adverse side effect. Since no significant loss of disk height, kyphosis, or segmental instability did occur, this minimal invasive procedure may be a valuable additional option in the operative treatment of the cervical disk prolapse.I confirm having declared any potential conflict of interest for all authors listed on this abstractNoDisclosure of InterestNone declaredBöhm H, Greiner-Perth R, et al. A new minimally invasive posterior approach for the treatment of cervical radiculopathy and myelopathy. Surgical technique and preliminary results. European Spine Journal 2003;12:268–273Brunaeu M, Cornelius Jf, George B., et al. Microsurgical cervical nerve root decompression by anterolateral approach. Operative Neurosurgery 2006;2:108–113Cloward RB: The anterior approach for removal of ruptured cervical discs. Journal of Neurosurgery 1958;15:602–617Fontanella A. Endoscopy microsurgery in herniated cervical discs. Int Intradiscal Therapy Soc Inc Tenth Ann Meet, Naples, Florida, 1997 (Neurological Research 01 (1999) 21:31–38)Fontanella A. Minimally invasive neurosurgery. A convincing alternative to open surgery. Rivista di Neuroradiologia 1997; 10:541Fritsch EW, Pitzen T. Zervikale Bandscheibenprothesen. Der Orthopäde 3 2006;35:347–361Heidecke V., Vogel S., Beurkert W. et al. Ergebnisse nach ventraler Fusion mittels Carbon-bzw. Titancage bei zervikalen Bandscheibenvorfällen. Dissertation zur Erlangung des akademischen Grades Doktor der Medizin. (2004)Hilton L. Minimally invasive tubular access for posterior cervical foraminotomy with three dimensional microscopic visualizationand localization with anterior/posterior imaging. The Spine Journal 2007;7:154–158

Height and torsional stiffness are most sensitive to annular injury in large animal intervertebral discs

Acute annulus fibrosus injury has been identified as a contributing factor to intervertebral disc (IVD) degeneration. Injuries as small as those resulting from needle injection result in localized mechanical disruption via fiber breakage, but it is unknown whether these injuries initiate degeneration locally or through changes in the mechanical behavior of the entire disc. However, in vitro biomechanical studies of injury are limited to a single type of injury or measurements in only one or two degrees of freedom. The aim of this study is to provide a comprehensive assessment of the joint level mechanical response to IVD injuries of various sizes in a large animal model. We hypothesize that annular injuries will affect disc mechanics differently depending on size, location, and mode of loading. We further hypothesize that a large injury to one side of the disc will induce a bending moment reaction under axial compression, which may decrease spinal column stability. A comprehensive biomechanical study investigating effects of small and large injuries on IVD pressurization and six-degree-of-freedom stiffness behaviors using bovine motion segments. Bovine caudal motion segments were subjected to a series of annular injuries ranging from 21-gauge needle puncture to 10-mm scalpel incisions and evaluated before and after injury with both mechanical testing under multiple degrees of freedom (axial compression, flexion-extension, lateral bending, and torsion) and nucleus pulposus (NP) fluid pressurization tests. Mechanical tests showed that axial torsional stiffness and disc height under resting compressive load were the parameters most sensitive to large annular injury. Bending and compressive stiffnesses, as well as bending moments induced by axial compression, were not significantly changed by scalpel incisions. Additionally, large injuries resulted in altered relaxation behavior after NP pressurization indicative of increases in both radial bulge compliance and fluid flow rates. These findings suggest that loss of disc height, torsional stiffness, and NP fluid pressurization are the immediate results of acute annular injury and are therefore those properties that IVD repair strategies must strive to restore or maintain. The lack of change in bending stiffness and moment under compression suggests that acute annular tears alone are not sufficient to induce off-axis motion and instability.

Childhood discitis in a regional children’s hospital

Childhood discitis is rare, can be difficult to diagnose and it is unclear whether it is an infective or simply an inflammatory process. A departmental database search of 46 434 patients identified 12 cases from 1990-2008. The mean time to diagnosis from onset was 22 days. The children usually present with altered gait, a normal infection screen (temperature, white cell count, C-reactive protein, blood cultures) and radiographic loss of intervertebral disc height. Antibiotics were given in 11 cases and but no immobilization was used. Symptoms resolved by a mean of 6.5 weeks with no recurrence. This study highlights the unusual features of this rare condition which should be confirmed with MRI scanning.

Quantitative assessment of abdominal aortic calcification and associations with lumbar intervertebral disc height loss: the Framingham Study

Vascular disease has been proposed as a risk factor for disc height loss (DHL).To examine the relationship between quantitative measures of abdominal aortic calcifications (AACs) as a marker of vascular disease, and DHL, on computed tomography (CT).Cross-sectional study in a community-based population.Four hundred thirty-five participants from the Framingham Heart Study.Quantitative AAC scores assessed by CT were grouped as tertiles of "no" (reference), "low," and "high" calcification. Disc height loss was evaluated on CT reformations using a four-grade scale. For analytic purposes, DHL was dichotomized as moderate DHL of at least one level at L2-S1 versus less than moderate or no DHL.We examined the association of AAC and DHL using logistic regression before and after adjusting for cardiovascular risk factors and before and after adjusting for age, sex, and body mass index (BMI).In crude analyses, low AAC (odds ratio [OR], 2.05 [1.27-3.30]; p=.003) and high AAC (OR, 2.24 [1.38-3.62]; p=.001) were strongly associated with DHL, when compared with the reference group of no AAC. Diabetes, hypercholesterolemia, hypertension, and smoking were not associated with DHL and did not attenuate the observed relationship between AAC and DHL. Adjustment for age, sex, and BMI markedly attenuated the associations between DHL and low AAC (OR, 1.20 [0.69-2.09]; p=.51) and high AAC (OR, 0.74 [0.36-1.53]; p=.42).Abdominal aortic calcification was associated with DHL in this community-based population. This relationship was independent of cardiovascular risk factors. However, the association of AAC with DHL was explained by the effects of age, sex, and BMI.