Journal of Global Pharma Technology Available Online at

Size: px

Start display at page:

Download "Journal of Global Pharma Technology Available Online at"

Thomasine Bradley
5 years ago
Views:

Journal of Global Pharma Technology Available Online at www.jgpt.co.

1 Journal of Global Pharma Technology Available Online at ISSN: RESEARCH ARTICLE Comparison of Three Different Configuration Posterior Instrumentation of Synbone Bone Model of Adolescent Idiopathic Scoliosis Lenke 1: In-Vitro Test of Biomechanical S. Dohar a. L. Tobing 1, Hendar Nugrahaedi Priambodo 2* 1. Department of Orthopaedics and Traumatology, Faculty of Medicine Universitas Indonesia Cipto Mangunkusumo Hospital. 2. Department of Orthopaedics and Traumatology, Faculty of Medicine Universitas Indonesia Cipto Mangunkusumo Hospital. *Corresponding Author: Hendar Nugrahaedi Priambodo Abstract Introduction Biomechanical construction test of posterior instrumentation for scoliosis correction is needed to evaluate reliability and instrumentation performance. Latest biomechanical testing have validated bone model as a suitable substitute. Low pedicle screw density can correct without significant complication. This study compared biomechanics of three posterior instrumentations: Bilateral Pedicle Screw (BPS), pedicle screw on proximal end, apex, distal end concave side (PAD), and PAD with sub laminar wire the concave side (PAD+SW). Method Three groups of vertebral model of Scoliosis Lenke I Synbone is equipped with configurations of 15 samples posterior instrumentations divided into three groups of BPS, PAD, PAD+SW. Each of the static tests is given axial force gradually from 50N, 100N, 150N, and 200N using Tensilon AMD RTF-1310 from Japan, with dial indicator Mitutoyo, Japan. Total displacement was measured for each group. Stiffness was also analyzed using load-displacement ratio. Results.BPS as the current gold standard showed minimal displacement, followed by BPS, PAD and PAD+SAW for 50N (p<0.001), 100N (p<0.001), and 200N (p<0.001) force, and was not significant for 150N (p=0.086). There was also significant difference between the stiffness of BPS, PAD and PAD+SW for 50N (p=0.002), 100N (p<0.001), 150N (p<0.001) and 200N (p<0.001) Conclusion. For biomechanical testing with static test, type of posterior instrumentations showed significance relationship with displacement and stiffness. BPS groups were more rigid compared to PAD+SW and PAD. Low density of pedicle screw resulted in the decrease of stiffness and posterior instrumentation sub laminar wire addition significantly added the strength. Keywords: Posterior instrumentation, adolescent idiopathic scoliosis, Lenke I, In Vitro. Introduction Sscoliosis is a 3 dimension deformity of spine, where curvature is more than 10 degree that could be seen from Antero-posterior projection by cobb technique [1]. The deformity caused several health problems in pulmonary and cardiac system. Correction of scoliosis is aimed to fix the deformity, keep the sagittal balance and increase the cardio pulmonary function, decrease morbidity and pain, and prevent further injury of the spine. The operation approach it self-consisted of anterior, posterior and booth. The ideal fixation that is used should be safe and reliable with minimum failure rates and could bear the weight without external support. The instrument that is used must not cause another deformity, easy in setting and minimum time of operation [2].Spine instrumentation is aimed to keep the spine stableuntil the fusion is done. The fusion itself involving more than 10 segments of the vertebra.[3]the instrumentation consist of vertebral anchor (screw, wire), longitudinal component (rod) and transversal component ( connector).[4]pediclescrew is useful in increasing rigidity, lesser bleeding and shorter operation period. However the unit cost of Pedikel Screw is relatively high. Although the journal about instrumentation is quit abundance yet there is still no consensus of operation in each curvature. There is inconsistency in numbers and type of instrument insertion among surgeons. [5] This research is testing biomechanics , JGPT. All Rights Reserved 53

2 strength in synbone scoliosis lenke 1 where curvature is at T4-T12. Synbone is used to make the observation of level fusion easy. This research is aimed to test biomechanical difference in several methods of posterior instrumentation in Synbone scoliosis type I. The instrumentation that are used in this research are Bilateral Pedicle screw (BPS) as the golden standard, Pedicle Screw at proximal end, apex, distal end curvature with sublaminar wire(pad + SW) and Pedicle Screw at proximal end apex and distal curvature ( PAD ). These three configurationsare hoped to be the base of choosing the fixation type in achieving fusion. Material and Methods This research is an experimental study with posttest only controls group design during February 2016 until March The biomechanics test data was recorded at physics and mechanical engineering lab Institute Technologyi Bandung, West Java, Indonesia. The number of sample for each group is 5. Subjects are spine model from Synbone Scoliosis Lenke type I with thoracic curvature T4-T12. The implant that are used are Pedicle Screwmonoaxial Patriot diameter 4,5mm lenght 35mm, monoaxial Patriot diameter 5,5mm length 35 mm, rod patriot diameter 6mm length 400mm, crosslink Patriot, cerclage wire synthesis 1,25. Posterior wire insertion is done simultaneously with scoliosis correction. This was done to all samples, the area were Th5 to L 1. (Figure1.) Figure 1: The impacts that were used in the research. (A) Pedicle Screwmonoaxial Patriot diameter 4,5mm lenght 35mm (B) monoaxial Patriot diameter 5,5mm length 35 mm, rod patriot diameter 6mm length 400mm, crosslink (C), crosslink Patriot, cerclage wire synthesis 1,25 Group A: Pedicle screw in all pedicle area from proximal end to distal end/ Bilateral Pedicle Screw Group B: Two Pedicle Screws at proximal end and distal end; two sekruppedikel in apex at concave side and at the distal it is combined with sub laminar wire at the concave side ( PAD SW) and pedicle screw at all pedicle in convex side. Group C: Two pedicle screws at proximal end and distal end; two pedicle screwat apex at the concave side and pedicle screw in all along the convex side (PAD) A mounting are made in spine model which previously been inserted with instrumentation at proximal and distal side with screw. To detect angular and whole movement at segment T5-L1 we put a sensor (Dial Indicator Mitutoyo) at these three points, T5, T10 and L1. Mechanical strength test then applied to the spine model, by giving weight that increase gradually. Start from 0 N, 50 N, 100 N, 150 N, 200 N. This mechanical strength test is done by using Tensilon AMD RTF 1310 (Made in Japan) with sensor recorder (Dial Indicator Mitutoyo ) at three point that had been given base to the rod that lies parallel to the vertebrae T5, T10 and L1. The amount of axial sole force that gradually given is 200 N. Dial Indicator Mitutoyo will display numbers that presents the translation that happened. Evaluation , JGPT. All Rights Reserved 54

Evaluation is done by calculating the data obtained from Tensilon AMD RTF-1310 (Made in Japan) and Dial Indicator Mitutoyo that is inserted in T5, T10, L1 in Synbone spine Model.

Samples then are grouped into three different methods of instrumentation insertion.

3 Evaluation is done by calculating the data obtained from Tensilon AMD RTF-1310 (Made in Japan) and Dial Indicator Mitutoyo that is inserted in T5, T10, L1 in Synbone spine Model. Figure 2: Tensilon AMD TRF-1310 Result This research use 15 scoliosis Lenke 1 spine models (made by Synbone) which weight, wide and height are similar. Samples then are grouped into three different methods of instrumentation insertion. The axial and torsional force are the cause of scoliosis, each sample is inserted with posterior instrumentation with different configuration. Posterior instrumentation consists of pedicle screw, rod, sub laminary wire, andcross link. At BPS configuration pedicle screw is used from proximal end to distal end. PAD configuration consists of pedicle screw, two pieces at proximal end, apex, distal end concave side and all pedicle screw at convex side. PAD+SW configuration consist of PAD configuration plus sub laminar wire in every laminar at concave side. Each group then given axial force gradually start from 50 N, 100 N, 150 N, and 200 N. This force will cause the construction of back instrumentation bend, followed by shifting of spine segment. Table 4.1 shows that the biggest displacement is at PAD Group while SPB has the smallest displacement. Compared to the other group, displacement in PAD group is the biggest regardless the applied force. Figure 4.2 shows SPB is superior than PAD and PAD+SW in every level of force. The biggest displacement happened in T10 segment. Table 1: Mean displacement of each group with all forces given Mean Displacement (mm ±SD) 50N 100N 150N 200N BPS 0.72± ± ± ±0.11 PAD+SW 0.85± ± ± ±0.21 PAD 0.92± ± ± ±0.16 Significant test * <0.001 < <0.001 Figure 4.2: Relationship graphic between force and displacement from every group , JGPT. All Rights Reserved 55

4 Normality test is done to all groups. The data is normally distributed in 50N group ( Saphiro Wilk p = 0.079). The difference on the three group is significant (ANOVA p=0.001). Significant difference is also found at BPS and PAD+SW (post hoc Bonferroni, p=0.000), BPS and PAD (post hoc Bonferroni, p=0.000) and between PAD and PAD+SW (post Hoc Bonferroni p=0.001). The data is normally distributed in 100N Group. We found that difference is the three group is significant (ANOVA p<0.001). Post hoc Bonferroni significance is also found in BPS and PAD+SW (p=0.006) SPB and PAD (p=0.000) and PAD and PAD+SW (p=0.000),on 150N data is normally distributed with Shapiro-Wilk normality test (p=0.396). Proceed to ANOVA with significantly difference between three group (p<0.001). Post Hoc Banferroni test, there was no difference between BPS and PAD+SW (p=0.457), BPS with PAD (p=0.094), and PAD+SW with PAD (p=1.00).data is normally distributed in 200N group, and significant difference is found in the three group. Significant difference is also found in BPS with PAD+SW (p<0.000), SPB with PAD (p<0.001), PAD and PAD+SW (p=0.002). Table 2: Stiffness on every group based on force Kekakuan (N/mm) SPB1 SPB2 SPB3 SPB4 SPB5 50N N N N SW1 SW2 SW3 SW4 SW5 50N N N N PAD1 PAD2 PAD3 PAD4 PAD5 50N N N N Table 4.3 shows that the biggest stiffness happened in BPS group while the smallest stiffness is in PAD group. Regardless the applied force, stiffness that happened in BPS group is bigger than any other group. On the contrary, stiffness that happened in PAD is the smallest compared to other group. PAD+SW group has more stiffness than PAD group and this might explain that the additional of sub laminar wire increase the stiffness of posterior instrumentation. Normality test was done before head. 50N group is not normally distributed (saphirowilk p=0.04) and the difference between three group is not significant ( kruscall wall is p=0.002). 100N group is normally distributed and the difference between three groups is significant (ANOVA p<0.001). Post hoc Bonferroni test yield significant difference in BPS with PAD+SW (p=0.001), BPS with PAD (p=0.000), PAD and SW (p=0.000). 150N group is normally distributed with Shapiro wilk (p=0.191) all the three group differs significantly (ANOVA p<0.001). post hoc Bonferroni Significant test showed different also found in BPS with PAD + SW (p=0.000) and BPS with PAD (=0.000) and PAD+PAD SW (p=0.000). 200N group is normally distributed with Shapiro wilk (p=0.104) all the three group differs significantly (ANOVA p<0.001). post hoc Bonferroni Significant test showed different also found in BPS with PAD + SW (p=0.000) , JGPT. All Rights Reserved 56

5 and BPS with PAD (=0.000) and PAD+PAD SW (p=0.004) Discussion This study used model to simulate artificial spinal scoliosis Lenke made by special polyurethane material. The use of this Synbone aims to minimize the variability of test results between the test sample so that the bone density, bone size, simulation of scoliosis can be made homogeneous between samples. Moreover it eases to make observation on the existing deformity and the treatment group. Consideration division of the group is the density of pedicle screws. A previous study investigated the effect of density on the resulting corrections and its implications for the cost of surgery, duration of surgery and the addition of the use of wire sub laminar which aimed to gain the stability of posterior instrumentation with affordable cost. In practice, the selection of the density of pedicle screws depends on cobb angle, maturity and type of curvature but the cost of the operation should be in consideration. From a previous study, reducing the density of pedicle screws provide correction results that are not much different in terms of correction without causing complication. BPS group as the gold standard use18 pedicle screws, while PAD group use15 pedicle screws, andpad + SW group addsub laminar on each lamina on the concave side either it has pedicle screws or not. For PAD, pedicle screws configuration are 2 pieces mounted on the proximal end and 2 pieces at the apical and 2 pieces at the distal end on the concave side. There are no results that prove evidence implant high density gives good results radiographic and cosmetics in the case of AIS cobb angles <70 degrees, therefore we use PAD configuration by reducing the pedicle screws 3 pieces on the concave side [6, 7]. Application of gradual axial force start from 50 N, 100 N, 150 N, and 200 N is based on the research conducted by Gadgill et al. On the basis of these studies we conducted this study, but the constraints of our study is not yet able to make a simulation of torsional force and the same practice does not force to 300 N due to limitations of equipment and censor. for addition, in vitro assays cannot assess the effects of muscle who worked on the spinal area, therefore applied compressive preload relevant to the effects of spinal muscular work. Each group was given axial force is gradually starting with 50 N, 100N, 150 N, 200 N which resulted in the construction of the instrument behind the curve followed by a shift in the spinal segment. Stiffness was calculated from the gradient function loaddisplacement curve of the vector translation is generated when the load applied. In this study three sensors in pairs by grounding the high posterior instrumentation Th5, Th10 and L1, each sensor provide results different figures - different, this shows a shift change between the artificial spinal segment. Axial force that is given to each treatment group resulted in the shifitng of of spinal posterior instrumentation between back bone segments. It is characterized by a gradual curved rod in the sagittal plane as the provision of the axial force continues to increase. The results showed that the biggest shift is in the PAD group to a force of 50 N, 100 N, 150 N and 200 N at the sensor parallel to T10. PAD group with a lower density of the implant affects biomechanical posterior instrumentation, in this case where the load displacement axial force given intervertebral resulted in a shift in the segment. In this group, there is a vertebra that is not in the fixation with pedicle screws, consequently more displacement in the area around the apex of the arch scoliosis when given axial force. But in the case of scoliosis deformity correction, as long as Cobb angle of degrees, the reduction in density of the implant provides corrections they do not differ significantly, a lower cost. Given axial force on each sample group showed a shift in the entire field sagittal segment posterior instrumentation installed.. The result shows that the configuration of the SPB as the gold standard is the most rigid than the other two models (PAD, PAD + SW). This study uses three groups of posterior instrumentation configuration. Posterior instrumentation stiffness depends on the type of posterior instrumentation components andthe density of pedicle screws..in this case the stiffness of each group posterior instrumentation will be measured based on the load-displacement in the (N / mm). This study compares the rigidity of the various types of posterior instrumentation configurations on Synbone Lenke 1 which givencraniocaudal axial force on it. All types of posterior instrumentation , JGPT. All Rights Reserved 57

6 in this research have been used in clinical settings. This result alsoleads to the reduction of operation costs, time duration of operation.the use of sublaminar wire results are not much different in the case of a correction. Stiffness is defined as the ratio of the load-displacement models which has been installed with artificial spinal posterior instrumentation. A rigid posterior instrumentation is expected to keep the spine segment until fusion occurs. When axial force is applied to the model spine which has been installed with posterior instrumentation, flexion of the model of the spine in the sagittal field will be retained by posterior instrumentation circuits. Stabilization of posterior instrumentation is hoped to be achieved by changing the density of pedicle screws and adding sublaminar wire. The rigidity of PAD + SW group is increased with the addition of wire sub laminar on each lamina in the concave side.a although in general, significant difference is achieved with BPS group as the gold standard. A study on the effect of the density of pedicle screws to a correction of scoliosis References has been conducted by Rushton et al, this study showed that the density of pedicle screws do not have a significant impact on the correction of scoliosis, but it gives a direct influence on the rising operating costs. The ideal number for the density of pedicle screws is not complitely known but it should be able to gain satisfactory results and without complications with low density of pedicle screws.now, the use of pedicle screw have been increasingly popular among surgeons. In planning the operation for various types of scoliosis curvature, experience amongsurgeon regarding instrumentation system is very important. The use of kawat sub laminar which is installed through the lamina of the vertebrae, provide fixation from gravity force, especially at the apex. Using of sublaminar wire at some point enable the distribution of force as a result of scoliosis correction. In this study, the using of kawat sublaminar on each lamina in the concave side in PAD + SW group is aimed to add a fixation on posterior instrumentation. PAD + SW group showed an increase in stiffness when compared with the PAD group. 1. Ersberg A, Gerdhem P (2013) Pre- and postoperative quality of life in scoliosis. Acta Orthop. 84(6): Ameri E, Ghandari H, Hesarikia H, Rasouli H, Vahidtari H, Nabizadeh N(2013) Comparison of Harrington Rod and Cotrel-Dubousset devices in Surgical Correction of Adolescent Idiopathic Scoliosis. Trauma Mon. 18(3): Gadgil A, Ahmed E, Rahmatalla A, Dove J, Maffulli N (2002) A study of the mechanical stability of scoliosis constructs using variable numbers of kawat sublaminars. Eur Spine J. 11: Sud A, Tsirikos A (2013) Current Concepts and controversies on adolescent idiopathic scoliosis: Part I. Indian J Orthop. 47(2): Carl-Eric A, Hubert L, Oana C C(2007) Variability of spinal instrumentation configurations in adolescent idiopathic scoliosis. Eur Spine J. 16: Maruyama T, Takeshita K (2009) Surgery for Idiopathic Scoliosis: Currently Applied Techniques. Clin Med Pediatr. 3: Gotfryd AO, Avanzi O (2013) Randomized clinical study on surgical techniques with different sekrup pedikel densities in the treatment of adolescent idiopathic scoliosis types Lenke 1A and 1B. Spine Deform. 1(4): , JGPT. All Rights Reserved 58

Spinal Deformity Pathologies and Treatments

Spinal Deformity Pathologies and Treatments Scoliosis Spinal Deformity 3-dimensional deformity affecting all 3 planes Can be difficult to visualize with 2-dimensional radiographs Kyphosis Deformity affecting