Purpose: To investigate the potential value of titanium anterior interbody cages compared to morselized rib graft for anterior interbody fusion in combination with posterior instrumentation, correction and fusion for Scheuermann’s kyphosis.

Methods and Materials: A Non-Randomised historic cohort study of two surgical techniques in matched subjects was carried out.15 patients with identical pre-operative radiographic and physical variables (age, gender, height, weight, BMI ) were managed with combined anterior release, interbody fusion, posterior instrumentation, correction and fusion . Group A (n=8) had morsilized rib graft inserted into each intervertebral disc space. Group B (n=7) had titanium interbody cages packed with bone graft inserted at each level. The posterior instrumentation extended from T2 to L2 in both groups. Pre- and post-operative curve morphometry was studied on plain radiographs by two independent observers. The indices studied included Cobb angle, Ferguson’s angle(FA) , Voutsinas index(VI), Sagittal Vertical Axis (SVA), Sacral Inclination (SI) and Lumbar Lordosis (LL). Interbody Fusion was assessed at final follow up. Each patient was reviewed at 3, 6, 12, 24, 48 and 60 months following surgery with standing radiographs. Wilcoxon-matched pairs test and Mann-Whit-ney test were used for statistical analysis.

Results: The average follow-up for groups A was 70 and Group B,66 months. For the whole group, the pre-operative : postoperative median Cobb angle, FA, VI, SVA and SI were 86: 42degrees, 50 : 28.4degrees, 28.7 :13, −3.5 : −4.0 centimetres and 40 : 34 degrees respectively. There were significant differences for all variables [p< 0.01] indicating good correction. At four-year follow-up, fusion criteria were satisfied in 12 / 15 cases (80%). Three patients had distal junctional kyphosis. There was no significant difference with respect to the variables between the two groups and both retained the post-operative correction achieved.

Conclusion: There was no significant advantage in the use of anterior titanium interbody cages over the use of morselized rib graft in the surgical management of Scheuermann’s Kyphosis.

Purpose: To study acute effects of Intradiscal Electrothermal Therapy(IDET) on biomechanical properties of human intervertebral discs using Scanning Acoustic Microscopy(SAM) and 11.6 Tesla Nuclear Magnetic Resonance(μNMR)Microscope.

Materials and Methods: Five SpineCATH® IDET catheters (Smith& Nephew) were sited in the lumbar discs of a fresh frozen human cadaver under image control. 6 regions of interest (ROI) – anterior middle (AM), right anterolateral (RAL), left anterolateral(LAL), posterior middle(PM), right posterolateral (RPL) and left postero-lateral (LPL) were marked. These ROI were then subjected to SAM (50MHz, Kremer GmbH).

SAM was performed in C-scan mode(gate width 50ns, depth 3500ns) and acoustical data collected along X–Y plane/depth Z. A B- mode scan acquired acoustic data along X–Z plane/ depth A. Time-of-Flight (TOF) scan used to create 3D-like images based on distance between the top of the disc and maximum penetration depth.

The IDET catheters were heated according to the 90⁰C 16.5-minute protocol. Discs were subjected to SAM using identical protocols as described. The ROIs were incised and analysed using μNMR. A custom made device was fabricated to prevent rotational effects of varying orientation of the specimen in the magnetic field.

Results: 30 ROI were studied using SAM and μNMR. Acoustic Impedance was significantly decreased (p< 0.01)on SAM and these changes were confined only to LPL and LAL.

Non-linear regression analysis of Signal Intensity Ratios of 30 different regions using SPSS showed a significant change in T1 weighting on μMRI by a median factor of 40 ( IQR + 16) for the LPL and 20(IQR + 8) for LAL regions. Significant relaxation difference (p< 0.001) caused by “magic angle”effects wer noted in LPL compared to RPL.

Conclusion: This is the first study depicting structure of human intervertebral discs using 11.6T μMRI and SAM and exploring its clinical potential. The study irrefutably proves that IDET decreases stiffness coefficient only in the treated area. The findings on SAm closely mimicked findings on μMRI.