Disc Fusion Research Articles

P155. Preoperative Disc Height as a Predictor of Success in Lumbar Disc Replacement or Fusion Surgery

P155. Preoperative Disc Height as a Predictor of Success in Lumbar Disc Replacement or Fusion Surgery

4:51142. Is the Motion “Normal” after Multi-Level Lumbar Disc Replacement? – Analysis of Motion at Each Treated and Adjacent Levels after 1 To 3-Level Disc Replacement versus Fusion

4:51142. Is the Motion “Normal” after Multi-Level Lumbar Disc Replacement? – Analysis of Motion at Each Treated and Adjacent Levels after 1 To 3-Level Disc Replacement versus Fusion

Does Bioresorbable Cage Material Influence Segment Stability in Spinal Interbody Fusion?

To reduce long term complications associated with nonresorbable interbody fusion cages, bioresorbable cages are being developed. We investigated the influence of bioresorbable cage material on segment stability, intervertebral disc height and fusion in vivo using radiostereometric analysis comparing 70/30 poly(L-lactide-co-D,L-lactide) (PLDLLA) cages with titanium cages. Twenty-eight goats were randomized to receive PLDLLA (n = 21) or a titanium control (n = 7) cage at L3-L4. Range of motion for flexion and extension and change in intervertebral disc height were measured before and after surgery and at followup (3, 6, and 12 months). Fusion was graded with a validated radiographic score. Although the PLDLLA cage could not provide the optimal environment for a successful high fusion rate, the range of motion of the PLDLLA segments gradually decreased in time and was similar to the titanium control group at 12 months. In addition the decrease of intervertebral disc height was similar for both PLDLLA (1.4 +/- 0.8 mm) and titanium (1.3 +/- 1.0 mm) specimens. Both results showed a bioresorbable cage does not lead to less decrease of motion or more loss of intervertebral disc height in time compared to titanium. This study therefore supports further development of a bioresorbable cage concept.

Endoscopic Extruded Screw Removal after Anterior Cervical Disc Fusion: Technical Case Report

Symptomatic complications related to screw migration and extrusion after anterior cervical disc fusion are uncommon. We report a case of significant dysphagia owing to late screw migration. An endoscopic transpharyngeal removal was performed without pharyngeal closure and with relief of symptoms. A transpharyngeal endoscopic approach to remove loose anterior cervical hardware is feasible and warrants further evaluation.

Comparison of Cervical Disk Implants and Cervical Disk Fusion Treatments in Human Cadaveric Models

Articulating cervical disk implants have been proposed as an alternative to disk fusion in the treatment of cervical disk disease. To examine the mechanical effect of articulating cervical disk implants (ACDI) versus simulated cervical disk fusion, a mechanical test device was constructed and cadaveric tests were carried out. While results show little effect on the pressures above and below the treatment level, the percent hysteretic behavior of the specimens trended to be higher for the ACDI, indicating that these implants retain more of the natural energy absorption capability of the cervical spine.

Lumbar Disc Arthroplasty versus Fusion for Single-Level Degenerative Disc Disease: Two-Year Results from a Randomized Prospective Study

Arthrodesis of the lumbar spine is associated with lack of pain relief, loss of motion, pseudoarthrosis, sagittal balance malalignment, and adjacent segment disease. Recently, total disc replacement (TDR) has become an alternative to spinal fusion, which may prevent these complications while providing equivalent or improved outcomes. We report the single-surgeon, single-site results from a multicenter, randomized, prospective study comparing lumbar TDR with ProDisc-L with circumferential fusion. Thirty-seven patients met strict inclusion criteria. There were 5 patients in the fusion group (average age 38) and 32 patients in the ProDisc-L group (average age 41). Multiple linear regression analysis revealed that TDR significantly reduced operating times (87 versus 141 minutes, P = 0.01) and length of hospital stay (4.1 versus 5.4 days, P = 0.02). TDR subjects demonstrated equivocal overall patient satisfaction and Oswestry scores throughout 2-year follow-up. VAS scores were significantly higher in fusion patients at 18 months ( P = 0.02), while TDR patients had significant improvement in SF-36 at 6 weeks following surgery compared with fusion patients ( P = 0.04). TDR patients exhibited significantly increased range of motion at the operative level at 18 months following surgery ( P = 0.03), whereas fusion patients demonstrated a trend toward increasing range of motion at the proximal adjacent level over time ( P = 0.06). TDR patients had significantly increased anterior disc heights compared with fusion patients at 24 months ( P

Complications of Lumbar Artificial Disc Replacement versus Fusion: Results from the Randomized, Multicenter Food and Drug Administration Investigational Device Exemption Study of the CHARITÉ Artificial Disc

Complications of Lumbar Artificial Disc Replacement versus Fusion: Results from the Randomized, Multicenter Food and Drug Administration Investigational Device Exemption Study of the CHARITÉ Artificial Disc

P85. An economic analysis of lumbar total disc replacement vs. fusion

P85. An economic analysis of lumbar total disc replacement vs. fusion

Vocal fold mobility following anterior cervical disk surgery: A randomized prospective study

Problem: The true incidence of vocal fold dysfunction following anterior cervical disk fusion (ACDF) is unknown, with few studies documenting laryngeal examination before and after surgery. Consequently, the effect of potential interventions such as limiting endotracheal tube cuff pressure and its effect on this incidence cannot be properly assessed. Methods: This study was a randomized, prospective clinical trial performed at an academic institution. Over a 4-year time period, patients undergoing primary ACDF surgery volunteered to participate. Preoperative and postoperative laryngeal endoscopy was performed. Recorded examinations were reviewed by independent laryngologists for determination of vocal fold mobility. Patients were randomized intraoperatively into 2 groups: a control group and an intervention group. Patients in the intervention group had endotracheal tube cuff pressures maintained below 20 mmHg throughout the surgical procedure. Results: One hundred patients were studied and randomized into 2 groups of 50 patients each. In the acute postoperative period, vocal cord paresis was seen in 8% and paralysis in 4% of studied patients. There was no significant difference in paresis or paralysis rates of the vocal fold on the side of surgery between the control and intervention groups. Conclusion: Vocal cord dysfunction is a common complication of ACDF surgery that can result in significant patient morbidity. Manipulating endotracheal tube cuff pressures did not decrease the risk of intraoperative recurrent laryngeal nerve injuries. Significance: This study demonstrates the true incidence of vocal fold dysfunction after ACDF surgery and that this incidence is unaltered by intraoperative interventions such as reducing endotracheal tube cuff pressures. Support: None reported.

Plate fixation adds stability to two-level anterior fusion in the cervical spine: a randomized study using radiostereometry

This study evaluated whether addition of a cervical spine locking plate (CSLP) in two-level disc fusions improved the postoperative stability and reduced the time to healing. Radiostereometric analysis was used to obtain precise recordings of the three-dimensional motion between the fused vertebrae. Eighteen consecutive patients were operated on with excision of two adjacent cervical discs and anterior horseshoe grafting with autologous bone (Smith Robinson technique). Nine patients were randomized to stabilization with autologous bone grafting and CSLP plate fixation and nine patients to grafting without fixation. Clinical symptoms in terms of pain in the neck and the arm were analysed preoperatively and after 1 year using a visual analogue scale (VAS). The patients operated without a plate displayed increased rotations around the transverse axis, corresponding to the development of a kyphosis [mean value no plate/plate 14.4 degrees/0.8 degrees (repeated measure ANOVA: P < 0.01)]. The mean compression was 3.2 mm larger in patients operated without a plate (repeated measure ANOVA: P < 0.01). Patients operated without a plate had more arm pain at the 1-year follow up (P < 0.05, Mann-Whitney U test). The VAS score for neck pain did not differ significantly between the two groups. Plate fixation could not be demonstrated to increase the healing rate, promote more rapid fusion or influence the frequency of graft complications.

Atlas of Spinal Surgery

The lumbar disc and related problems lumbar fusion the cervical disc and related problems cervical spondylosis and fracture thoracic disc congenital anomalies arteriovenous malformations spinal cord tumours missile wounds procedures for pain.

Glass disk fusion method for the X‐ray fluorescence analysis of rocks and silicates

AbstractA study of the physical and practical aspects needed for a successful solid solution method for XRF analysis is presented in the light of the theory and practice of the glass‐making industry. An inexpensive manual glass disk sample preparation method is proposed that gives a well annealed disk that can be ground and polished without any losses due to breakage.

Results of L4-L5 Disc Excision Alone Versus Disc Excision and Fusion

We evaluated the results of 85 patients having L4-L5 disc excision (52 having disc excision alone, and 33 having disc excision and fusion) using the Smiley-Webster scale at an average follow-up of 7.3 years. Both groups (fusion and nonfusion) were comparable except that the nonfusion group had a significantly higher percentage of patients with a history of chronic back pain and degenerative changes on their initial radiographs. The fusion group had significantly better results compared with the nonfusion group (85% satisfactory results versus 39% satisfactory results). The most common cause of unsatisfactory results in the fusion group was pseudarthrosis (two) while progressive degenerative disc disease (18) and recurrent disc prolapse (eight) were the most common cause of unsatisfactory results in the nonfusion group. The overall reoperation rate was 9.4% (13.5% in the nonfusion group, and 3% in the fusion group.

Treatment of kyphosis and lumbar stenosis in achondroplasia.

In summary, neurological symptoms in the achondroplast are related to the anatomical spinal canal with degenerative changes and aging altering the delicate biomechanical and microvascular balance. An accurate and detailed history is necessary for diagnosis. Decompression is via a posterior approach with a multi-level wide laminectomy with undercutting of the facets and usually multi-level foraminotomies. Kyphosis when present at the time of decompression, or if angular or progressive, requires treatment. A combined two-stage approach with an anterior disc excision and fusion combined with a posterior and posterolateral fusion is the treatment of choice. In angular deformities anterior strut grafting is indicated. The use of instrumentation posteriorly is contraindicated with the possible exception of transpedicular fixation. The instrumentation stabilizes the spine and does to correct the deformity. Using this approach the kyphosis in the achondroplast and the symptomatic spinal stenosis are adequately treated.

Formation of Chloroplast Membranes in Chlamydomonas reinhardi y-1: Effects of Inhibitors of Protein Synthesis

Abstract During normal greening of the y-1 mutant of Chlamydomonas reinhardi, photoreductive activities with 2,6-dichloroindophenol (DCI), an assay for Photosystem II, and with methyl red (ascorbate and DCI as electron donors), an assay for Photosystem I, increased in parallel with chlorophyll. Disc membranes formed approximately in parallel with chlorophyll synthesis and fused to form grana. In the presence of 20 µg of chloramphenicol (CAP) per ml, the cells produced chlorophyll and membranes at 90% of the rate of control cells, but photoreductive activities were drastically reduced. Photoreduction of DCI and of methyl red in CAP-treated cells increased at rates only 35% and 50%, respectively, of those in control cells. Also, in CAP-treated cells the discs rarely fused to form grana. Inhibition of these activities was reversible upon removal of CAP. Chlorophyll synthesis and disc formation in cells in the presence of cycloheximide (CHI) at 1 µg per ml occurred at about one-half of the rate of control cells, but photoreductive activity with DCI and disc fusion into grana was the same as in controls on a chlorophyll basis. At concentrations of CHI above 5 µg per ml, chlorophyll synthesis was completely inhibited. The incorporation of 14C-leucine into total protein by whole cells was inhibited maximally 30 to 50% by CAP and maximally 40 to 50% by CHI; the effects of the drugs were additive. The membranes formed in the presence of CAP could be repaired by transferring the cells to a medium containing CHI (10 µg per ml). During 2 hours of subsequent incubation in light, the existing membranes gained activity until, on a chlorophyll basis, they were at least as active as the membranes formed in control cells. These results indicate that products of both the cytoplasmic and the chloroplastic protein-synthesizing systems are required for disc membrane production in the chloroplast of this alga.