IntroductionThe pathogenetic mechanism of low back pain and nerve root damage in lumbar disc herniation is the subject of ongoing debate. In particular, given that the mechanicalischaemic hypothesis alone cannot explain the cause-effect relationship between disc degeneration and neurological impairment, a biochemical mechanism is likely to be involved. It has recently been demonstrated that the autologous nucleus pulposus can induce histological and functional changes in spinal nerve roots when applied epidurally [17]. Cells of the nucleus pulposus can produce prostaglandin E2, interleukin-1 and interleukin-6 (IL-6) [31], phospholipase A2 [26], and growth factors like fibroblast-like growth factor (FGF) [32] and insulin-like growth factor-1 (IGF-1) [18]. These factors are known to control cell metabolism and to promote inflammatory processes. Moreover, recent studies suggest a critical role for IL-6 and its receptor in the modulation of pain [8]. The mechanisms of action underlying the possible effect of these factors on spinal nerve root structure and function are, however, still unknown. In addition, the fact that nerve roots differ from peripheral nerves in their anatomical, biomechanical, and physiological properties prevents extrapolation from the extensive literature and the numerous experimental models of peripheral nerve compression to the pathophysiology of root injury [5,23,25]. The working hypothesis of the present study is that transforming growth factor-β1 (TGF-β1), IGF-1, IL-6 and IL-6-receptor (IL-6R) can be produced at the site of herniation. This hypothesis was immunohistochemically explored by analysing normal and protruded intervertebral disc tissue for these factors.Abstract Nerve root irritation induced by factors produced by the intervertebral disc may play a crucial role in the pathophysiology of sciatic pain production. In this study we used immunohistochemistry to investigate the presence of transforming growth factor-β1 (TGF-β1), insulinlike growth factor-1 (IGF-1), interleukin-6 (IL-6), IL-6-receptor (IL-6R) and fibronectin in lumbar disc bioptic specimens from 30 patients with disc herniation (protrusion type). Chondrocytes of herniated discs stained positive for TGF-β1, IGF-1, IL-6 and fibronectin. We demonstrated for the first time the presence of IL-6-R in the chondrocytes of herniated tissue. Specimens from autoptic healthy tissue were used as controls. In these sections no immunoreaction for TGF-β1, IL-6, or IL-6R was found, while they expressed IGF-1 and fibronectin, but in lower quantities than herniated discs. These results demonstrated the production of factors such as TGF-β1, IGF-1, IL-6, IL-6R and fibronectin at the site of lumbar disc herniation.

The classification system of spondylolisthesis proposed by Marchetti and Bartolozzi is the most practical regarding prognosis and treatment and includes the description of both low-and high-dysplastic developmental spondylolisthesis (HDDS). Unfortunately, it does not provide strict criteria on how to differentiate between these two subtypes. The accepted treatment for HDDS is surgical. However, there is no consensus on how to surgically stabilize this subtype of spondylolisthesis, and although the concept of reducing spinal deformity before fusion is attractive, the issue of surgical reduction versus in situ fusion remains controversial, especially for HDDS (Meyerding Grades III and IV). The purpose of this study was (1) to describe the severity index (SI) as a simple method that can be used in the identification of low-dysplastic developmental spondylolisthesis from HDDS allowing earlier surgical stabilization to prevent slip progression, (2) to provide guidelines for using the unstable zone for the inclusion of L4 in stabilization, and (3) to describe a surgical technique in the reduction and stabilization of this challenging surgical entity in an attempt to decrease the risk of iatrogenic L5 neurologic injury. The concepts of SI and unstable zone in the evaluation and treatment of HDDS are relatively new. In our study, patients with an SI value [20% were classified as having HDDS and surgical stabilization was offered. In addition, all vertebrae that were contained in the defined unstable zone were surgically instrumented and fused with attempts at anatomic reduction. This case series involved the retrospective radiological review of 25 consecutive patients surgically treated for HDDS between April 2000 and September 2004 by two senior surgeons. All 25 patients had a minimum 3-year follow-up. Reduction of slip, lumbosacral kyphosis, sacral inclination, fusion rate, maintenance of reduction, and iatrogenic L5 neurologic injury were evaluated. Twentytwo patients underwent a single-level L5-S1 fusion. Three patients had extension of the L5-S1 fusion to include L4 because it fell into the unstable zone. Slip improved from 67.2 to 13.6%, focal L5-S1 kyphosis improved from ?17.5°to -6.4°. There were no pseudoarthroses and all patients had radiographic evidence of solid bony fusion at latest follow-up. To date, there have been no re-operations secondary to progression of deformity or loss of fixation. Two re-operations were performed, one for a superficial wound infection, the other for further laparoscopic decompression for continued L5 nerve root symptoms after the index surgery. One patient developed an iatrogenic L5 radiculopathy with dysaesthesiae 3 days postoperatively which completely resolved over 6 weeks. HDDS is best treated surgically. Early identification and stabilization of this challenging surgical entity could prevent the progression of slip and deformity making the index surgery less technically demanding. Vertebrae that are contained in the unstable zone can be instrumented and stabilized ...

Compared with the standard transoral technique, the EEA provides the same good exposure but with potentially less complications. The preservation of the anterior C1 arch can contribute to avoid cranial settling and posterior fusion with its related risk of subaxial instability.

Bone morphogenetic protein (BMP), associated with N,N-dicarboxymethyl chitosan, is used to induce or facilitate the repair of articular cartilage lesions. This association is intended for the synergistic potentiation of the respective biological effects. Data show that BMP-7 enhances the in vivo proliferation of cells with chondrocytes phenotype in the articular environment, leading to partial healing of the articular surface of the lesions. N,N-dicarboxymethyl chitosan is found to be useful as a molecular carrier or drug delivery agent.

No abstract

Purpose To assess if the evaluation of the spino-pelvic balance can be effective in the surgical decision making of the high-grade high dysplastic developmental spondylolisthesis (HDDS). Methods Sixteen patients affected with high-grade HDDS (6 treated with ''in situ'' fusion, and 10 with reduction and fusion) were retrospectively evaluated. A clinical and radiological assessment of the deformity correction was carried out, with a minimum follow-up of 2 years. The differences between the pre-and postoperative measures were statistically analyzed using a two-tailed, paired t test. Results The six patients treated with ''in situ'' fusion showed no statistically significant change at the last followup relative to pelvic tilt (PT), sacral slope (SS), and grade, while the 10 patients treated with reduction showed significant changes: PT significantly decreased following surgery, while SS and grade significantly increased. Conclusions The analysis of the spino-pelvic sagittal balance allows to identify two types of HDDS: the balanced deformities, which do not need reduction, and the unbalanced deformities, in which correction is needed.

The results demonstrate that OP-1 combined with locally obtained autograft is a safe and effective alternative for iliac crest autograft in instrumented single-level posterolateral fusions of the lumbar spine. The main advantage of OP-1 is that it avoids morbidity associated with the harvesting of autogenous bone grafts from the iliac crest.

An in vitro study assessing the kinetics of drug release from antibiotic-fibrin seal compounds and the antibacterial efficacy of the delivered drug has been performed. Antibiotic sensitivity and the amount of drug released was measured by means of agar diffusion test. Standard and experimental curves were established for each antibiotic and each bacterial test in order to evaluate the quantities of the drug released during each 24 h period. The reconstitution of lyophilized human fibrin with an aqueous solution containing an antibiotic resulted in only minor modification of the clotting process, with the exception of those solutions containing cefotaxim and mezlocillin which failed to clot altogether and were excluded from further study. The evaluation of the kinetics of elution of the antibiotics from the fibrin clots showed that all of the antibiotics had been almost completely released by 96 h. The delivered amount of each drug was enough to maintain the Minimal Inhibitory Concentration (MIC) until the 4th day of culture for the most of antibiotics, resulting in a prolonged release of the drug.