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Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep. Medicina (B Aires) 2022; 58:medicina58070899. [PMID: 35888618 PMCID: PMC9319051 DOI: 10.3390/medicina58070899] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/27/2022] [Accepted: 07/04/2022] [Indexed: 11/17/2022] Open
Abstract
Background and Objectives: Spinal fusion is an effective and widely accepted intervention. However, complications such as non-unions and hardware failures are frequently observed. Radiologic imaging and physical examination are still the gold standards in the assessment of spinal fusion, despite multiple limitations including radiation exposure and subjective image interpretation. Furthermore, current diagnostic methods only allow fusion assessment at certain time points and require the patient’s presence at the hospital or medical practice. A recently introduced implantable sensor system for continuous and wireless implant load monitoring in trauma applications carries the potential to overcome these drawbacks, but transferability of the principle to the spine has not been demonstrated yet. Materials and Methods: The existing trauma sensor was modified for attachment to a standard pedicle-screw-rod system. Two lumbar segments (L2 to L4) of one Swiss white alpine sheep were asymmetrically instrumented. After facetectomy, three sensors were attached to the rods between each screw pair and activated for measurement. The sheep was euthanized 16 weeks postoperatively. After radiological assessment the spine was explanted and loaded in flexion-extension to determine the range of motion of the spinal segments. Sensor data were compared with mechanical test results and radiologic findings. Results: The sensors measured physiological rod loading autonomously over the observation period and delivered the data daily to bonded smartphones. At euthanasia the relative rod load dropped to 67% of the respective maximum value for the L23 segment and to 30% for the L34 segment. In agreement, the total range of motion of both operated segments was lower compared to an intact reference segment (L23: 0.57°; L34: 0.49°; intact L45: 4.17°). Radiologic assessment revealed fusion mass in the facet joint gaps and bilateral bridging bone around the joints at both operated segments. Conclusions: Observations of this single-case study confirm the basic ability of continuous rod load measurement to resolve the spinal fusion process as indicated by a declining rod load with progressing bone fusion. A strong clinical potential of such technology is eminent, but further data must be collected for final proof of principle.
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An TY, Kim JY, Lee YS. Risk Factors and Radiologic Changes in Subsidence after Single-Level Anterior Cervical Corpectomy: A Minimum Follow-Up of 2 Years. Korean J Neurotrauma 2021; 17:126-135. [PMID: 34760823 PMCID: PMC8558015 DOI: 10.13004/kjnt.2021.17.e23] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/02/2021] [Accepted: 08/27/2021] [Indexed: 11/15/2022] Open
Abstract
Objective Anterior cervical corpectomy using a titanium mesh cage may result in delayed nonunion and thus a change in cervical alignment, and patients may require revision surgery. We investigated the radiologic and clinical outcomes of cervical corpectomy and the risk factors for subsidence. Methods We studied 74 patients who underwent single-level anterior cervical corpectomy for cervical spondylotic myelopathy with or without ossification of the posterior longitudinal ligament between 2007 and 2014. Graft subsidence was considered present when there was a reduction in the anterior and posterior heights by an average of 4 mm or more 2 years after the operation. We measured cervical parameters before surgery, immediately after surgery, and 6, 12, and 24 months after surgery. The clinical outcomes were the neck and arm visual analog scale scores and reoperation rate. Results In the subsidence group, these values gradually decreased over the 24 months. The radiologic parameters did not differ between the 2 groups for 24 months after the onset of subsidence. There were no differences in clinical outcome or reoperation rate. In the analysis of the risk factors, subsidence occurred with a large T1 slope and a large change in the C27 Cobb angle (p=0.020 and p=0.026, respectively). Conclusion Subsidence gradually occurred after single-level anterior cervical corpectomy for up to 24 months. However, the presence of subsidence did not affect the radiologic and clinical outcomes. When the T1 slope was large and the C27 Cobb angle change was severe, more subsidence occurred.
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Affiliation(s)
- Tae Yong An
- Department of Neurosurgery, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Ji-Yoon Kim
- Department of Anesthesiology, Pain and Critical Care Medicine, School of Medicine, Kyungpook National University, Daegu, Korea
- Department of Anesthesiology, Pain and Critical Care Medicine, Kyungpook National University Chilgok Hospital, Daegu, Korea
| | - Young-Seok Lee
- Department of Neurosurgery, School of Medicine, Kyungpook National University, Daegu, Korea
- Department of Neurosurgery, Kyungpook National University Chilgok Hospital, Daegu, Korea
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Kim BJ, Kim SH, Lee H, Lee SH, Kim WH, Jin SW. Demineralized Bone Matrix (DBM) as a Bone Void Filler in Lumbar Interbody Fusion: A Prospective Pilot Study of Simultaneous DBM and Autologous Bone Grafts. J Korean Neurosurg Soc 2017; 60:225-231. [PMID: 28264244 PMCID: PMC5365286 DOI: 10.3340/jkns.2017.0101.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 02/02/2017] [Indexed: 01/28/2023] Open
Abstract
Objective Solid bone fusion is an essential process in spinal stabilization surgery. Recently, as several minimally invasive spinal surgeries have developed, a need of artificial bone substitutes such as demineralized bone matrix (DBM), has arisen. We investigated the in vivo bone growth rate of DBM as a bone void filler compared to a local autologous bone grafts. Methods From April 2014 to August 2015, 20 patients with a one or two-level spinal stenosis were included. A posterior lumbar interbody fusion using two cages and pedicle screw fixation was performed for every patient, and each cage was packed with autologous local bone and DBM. Clinical outcomes were assessed using the Numeric Rating Scale (NRS) of leg pain and back pain and the Korean Oswestry Disability Index (K-ODI). Clinical outcome parameters and range of motion (ROM) of the operated level were collected preoperatively and at 3 months, 6 months, and 1 year postoperatively. Computed tomography was performed 1 year after fusion surgery and bone growth of the autologous bone grafts and DBM were analyzed by ImageJ software. Results Eighteen patients completed 1 year of follow-up, including 10 men and 8 women, and the mean age was 56.4 (32–71). The operated level ranged from L3/4 to L5/S1. Eleven patients had single level and 7 patients had two-level repairs. The mean back pain NRS improved from 4.61 to 2.78 (p=0.003) and the leg pain NRS improved from 6.89 to 2.39 (p<0.001). The mean K-ODI score also improved from 27.33 to 13.83 (p<0.001). The ROM decreased below 2.0 degrees at the 3-month assessment, and remained less than 2 degrees through the 1 year postoperative assessment. Every local autologous bone graft and DBM packed cage showed bone bridge formation. On the quantitative analysis of bone growth, the autologous bone grafts showed significantly higher bone growth compared to DBM on both coronal and sagittal images (p<0.001 and p=0.028, respectively). Osteoporotic patients showed less bone growth on sagittal images. Conclusion Though DBM alone can induce favorable bone bridging in lumbar interbody fusion, it is still inferior to autologous bone grafts. Therefore, DBM is recommended as a bone graft extender rather than bone void filler, particularly in patients with osteoporosis.
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Affiliation(s)
- Bum-Joon Kim
- Department of Neurosurgery, Korea University Ansan Hospital, Ansan, Korea
| | - Se-Hoon Kim
- Department of Neurosurgery, Korea University Ansan Hospital, Ansan, Korea
| | - Haebin Lee
- Department of Neurosurgery, Korea University Ansan Hospital, Ansan, Korea
| | - Seung-Hwan Lee
- Department of Neurosurgery, Korea University Ansan Hospital, Ansan, Korea
| | - Won-Hyung Kim
- Department of Neurosurgery, Korea University Ansan Hospital, Ansan, Korea
| | - Sung-Won Jin
- Department of Neurosurgery, Korea University Ansan Hospital, Ansan, Korea
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Santoni B, Cabezas AF, Cook DJ, Yeager MS, Billys JB, Whiting B, Cheng BC. Comparison of Intervertebral ROM in Multi-Level Cadaveric Lumbar Spines Using Distinct Pure Moment Loading Approaches. Int J Spine Surg 2015; 9:32. [PMID: 26273550 DOI: 10.14444/2032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Pure-moment loading is the test method of choice for spinal implant evaluation. However, the apparatuses and boundary conditions employed by laboratories in performing spine flexibility testing vary. The purpose of this study was to quantify the differences, if they exist, in intervertebral range of motion (ROM) resulting from different pure-moment loading apparatuses used in two laboratories. METHODS Twenty-four (laboratory A) and forty-two (laboratory B) intact L1-S1 specimens were loaded using pure moments (±7.5 Nm) in flexion-extension (FE), lateral bending (LB) and axial torsion (AT). At laboratory A, pure moments were applied using a system of cables, pulleys and suspended weights in 1.5 Nm increments. At laboratory B, specimens were loaded in a pneumatic biaxial test frame mounted with counteracting stepper-motor-driven biaxial gimbals. ROM was obtained in both labs using identical optoelectronic systems and compared. RESULTS In FE, total L1-L5 ROM was similar, on average, between the two laboratories (lab A: 37.4° ± 9.1°; lab B: 35.0° ± 8.9°, p=0.289). Larger apparent differences, on average, were noted between labs in AT (lab A: 19.4° ± 7.3°; lab B: 15.7° ± 7.1°, p=0.074), and this finding was significant for combined right and left LB (lab A: 45.5° ± 11.4°; lab B: 35.3° ± 8.5°, p < 0.001). CONCLUSIONS To our knowledge, this is the first study comparing ROM of multi-segment lumbar spines between laboratories utilizing different apparatuses. The results of this study show that intervertebral ROM in multi-segment lumbar spine constructs are markedly similar in FE loading. Differences in boundary conditions are likely the source of small and sometimes statistically significant differences between the two techniques in LB and AT ROM. The relative merits of each testing strategy with regard to the physiologic conditions that are to be simulated should be considered in the design of a study including LB and AT modes of loading. An understanding of these differences also serves as important information when comparing study results across different laboratories.
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Affiliation(s)
| | | | - Daniel J Cook
- Allegheny Health Network, Department of Neurosurgery, Pittsburgh, PA
| | - Matthew S Yeager
- Allegheny Health Network, Department of Neurosurgery, Pittsburgh, PA
| | - James B Billys
- Allegheny Health Network, Department of Neurosurgery, Pittsburgh, PA
| | - Benjamin Whiting
- Allegheny Health Network, Department of Neurosurgery, Pittsburgh, PA
| | - Boyle C Cheng
- Allegheny Health Network, Department of Neurosurgery, Pittsburgh, PA
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Abstract
Background Laboratory spinal biomechanical tests using human cadaveric or animal spines have limitations in terms of disease transmission, high sample variability, decay and fatigue during extended testing protocols. Therefore, a synthetic biomimetic spine model may be an acceptable substitute. The goal of current study is to evaluate the properties of a synthetic biomimetic spine model; also to assess the mechanical performance of lateral plating following lateral interbody fusion. Methods Three L3/4 synthetic spinal motion segments were examined using a validated pure moment testing system. Moments (±7.5 Nm) were applied in flexion-extension (FE), lateral bending (LB) and axial rotation (AR) at 1Hz for total 10000 cycles in MTS Bionix. An additional test was performed 12 hours after 10000 cycles. A ±10 Nm cycle was also performed to allow provide comparison to the literature. For implantation evaluation, each model was tested in the 4 following conditions: 1) intact, 2) lateral cage alone, 3) lateral cage and plate 4) anterior cage and plate. Results were analysed using ANOVA with post-hoc Tukey’s HSD test. Results Range of motion (ROM) exhibited logarithmic growth with cycle number (increases of 16%, 37.5% and 24.3% in AR, FE and LB respectively). No signification difference (p > 0.1) was detected between 4 cycles, 10000 cycles and 12 hour rest stages. All measured parameters were comparable to that of reported cadaveric values. The ROM for a lateral cage and plate construct was not significantly different to the anterior lumbar interbody construct for FE (p = 1.00), LB (p = 0.995) and AR (p = 0.837). Conclusions Based on anatomical and biomechanical similarities, the synthetic spine tested here provides a reasonable model to represent the human lumbar spine. Repeated testing did not dramatically alter biomechanics which may allow non-destructive testing between many different procedures and devices without the worry of carry over effects. Small intra-specimen variability and lack of biohazard makes this an attractive alternative for in vitro spine biomechanical testing. It also proved an acceptable surrogate for biomechanical testing, confirming that a lateral lumbar interbody cage and plate construct reduces ROM to a similar degree as anterior lumbar interbody cage and plate constructs.
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Pelletier MH, Oliver RA, Christou C, Yu Y, Bertollo N, Irie H, Walsh WR. Lumbar spinal fusion with β-TCP granules and variable Escherichia coli-derived rhBMP-2 dose. Spine J 2014; 14:1758-68. [PMID: 24486479 DOI: 10.1016/j.spinee.2014.01.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 11/28/2013] [Accepted: 01/20/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT The ideal tissue-engineered solution for any bone graft substitute is to assist in the rapid formation of bone and facilitate fusion. PURPOSE The present study aims to evaluate this E-BMP-2 (Escherichia coli-derived human bone morphogenetic protein-2) in ovine posterolateral lumbar fusion (PLF) to examine the influence of dose and overall performance in a model with similar graft size and diffusive challenges to the human. STUDY DESIGN/SETTING In vivo large animal model study. METHODS An adult ovine PLF was performed in 30 animals with groups of E-BMP-2 with a beta-tricalcium phosphate (β-TCP) carrier at three different dosages, β-TCP alone, and autograft from the iliac crest. The fusions were assessed by radiography (X-ray and microcomputed tomography), mechanical testing, and hard-tissue histology with bone labels at 6, 8, and 10 weeks along with routine paraffin histology at 12 weeks. RESULTS Results showed increasing new bone and fusion rate with E-BMP-2 dose, whereas β-TCP alone was largely resorbed and did not achieve fusion in this model at 12 weeks. Autograft showed similar grading for the amount of bone between the transverse processes but a lower fusion rate than β-TCP/E-BMP-2 groups. Bone labels revealed new bone formation at all time points for the E-BMP2 groups, whereas the autograft group showed active bone formation at 10 weeks. Beta-tricalcium phosphate displayed reliable incorporation into the decorticated host bone, whereas limited new bone was found between the transverse processes. At the center of the fusion mass, increased E-BMP-2 dose led to increased incorporation of β-TCP by new bone. CONCLUSIONS These results suggest that E-BMP-2 was capable of producing posterolateral fusion in the ovine model that is equal to or superior to autologous graft in terms of fusion rate and mechanical strength. E-BMP-2 dose had considerable influence on β-TCP granule resorption.
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Affiliation(s)
- Matthew H Pelletier
- Surgical and Orthopaedic Research Laboratories, University of New South Wales, Prince of Wales Clinical School, Level 1 Clinical Sciences Building, Prince of Wales Hospital, Avoca St Randwick, New South Wales 2031, Australia
| | - Rema A Oliver
- Surgical and Orthopaedic Research Laboratories, University of New South Wales, Prince of Wales Clinical School, Level 1 Clinical Sciences Building, Prince of Wales Hospital, Avoca St Randwick, New South Wales 2031, Australia
| | - Chris Christou
- Surgical and Orthopaedic Research Laboratories, University of New South Wales, Prince of Wales Clinical School, Level 1 Clinical Sciences Building, Prince of Wales Hospital, Avoca St Randwick, New South Wales 2031, Australia
| | - Yan Yu
- Surgical and Orthopaedic Research Laboratories, University of New South Wales, Prince of Wales Clinical School, Level 1 Clinical Sciences Building, Prince of Wales Hospital, Avoca St Randwick, New South Wales 2031, Australia
| | - Nicky Bertollo
- Surgical and Orthopaedic Research Laboratories, University of New South Wales, Prince of Wales Clinical School, Level 1 Clinical Sciences Building, Prince of Wales Hospital, Avoca St Randwick, New South Wales 2031, Australia
| | - Hiroyuki Irie
- Osteopharma, Inc., Osteopharma YSK Building 2F, 1-2-5 Uchihommachi Cho-ku Osaka 540-0026, Japan
| | - William R Walsh
- Surgical and Orthopaedic Research Laboratories, University of New South Wales, Prince of Wales Clinical School, Level 1 Clinical Sciences Building, Prince of Wales Hospital, Avoca St Randwick, New South Wales 2031, Australia.
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Lumbar transpedicular implant failure: a clinical and surgical challenge and its radiological assessment. Asian Spine J 2014; 8:281-97. [PMID: 24967042 PMCID: PMC4068848 DOI: 10.4184/asj.2014.8.3.281] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 06/29/2013] [Accepted: 07/04/2013] [Indexed: 11/08/2022] Open
Abstract
Study Design It is a multicenter, controlled case study review of a big scale of pedicle-screw procedures from January 2000 to June 2010. The outcomes were compared to those with no implant failure. Purpose The purpose of this study was to review retrospectively the outcome of 100 patients with implant failure in comparison to 100 control-patients, and to study the causes of failure and its prevention. Overview of Literature Transpedicular fixation is associated with risks of hardware failure, such as screw/rod breakage and/or loosening at the screw-rod interface and difficulties in the system assembly, which remain a significant clinical problem. Removal or revision of the spinal hardware is often required. Methods Two hundred patients (88 women, 112 men) were divided into 2 major groups, with 100 patients in group I (implant failure group G1) and 100 patients in group II (successful fusion, control group G2). We subdivided the study groups into two subgroups: subgroup a (single-level instrumented group) and subgroup b (multilevel instrumented group). The implant status was assessed based on intraoperative and follow-up radiographs. Results Implant failure in general was present in 36% in G1a, and in 64% in G1b, and types of implant failure included screw fracture (34%), rod fracture (24%), rod loosening (22%), screw loosening (16%), and failure of both rod and screw (4%). Most of the failures (90%) occurred within 6 months after surgery, with no reported cases 1 year postoperatively. Conclusions We tried to address the problem and study the causes of failure, and proposed solutions for its prevention.
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Kim TH, Lee BH, Moon SH, Lee SH, Lee HM. Comparison of adjacent segment degeneration after successful posterolateral fusion with unilateral or bilateral pedicle screw instrumentation: a minimum 10-year follow-up. Spine J 2013; 13:1208-16. [PMID: 24075027 DOI: 10.1016/j.spinee.2013.07.431] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 02/20/2013] [Accepted: 07/03/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT In the instrumented fusion, adjacent segment facet joint violation or impingement by pedicle screws is unavoidable especially in cephalad segment, despite taking specific intraoperative precautions in terms of surgical approach. In such circumstances, unlike its original purpose, unilateral pedicle screw instrumentation can contribute to reduce the degeneration of cephalad adjacent segment by preventing contralateral cephalad adjacent facet joint from the unavoidable injury by pedicle screw insertion. However, to our knowledge, no long-term follow-up study has compared adjacent segment degeneration (ASD) between unilateral and bilateral pedicle screw instrumented fusion. PURPOSE To compare ASD after successful posterolateral fusion using either unilateral or bilateral pedicle screw instrumentation for patients with lumbar spinal stenosis and/or Grade 1 spondylolisthesis. STUDY DESIGN Retrospective case-control study. PATIENT SAMPLE One hundred forty-seven patients who had undergone one- or two-level posterolateral fusion with unilateral or bilateral pedicle screw instrumentation for lumbar spinal stenosis with or without low-grade spondylolisthesis and achieved successful fusion, with a minimum 10-year follow-up. OUTCOME MEASURE The occurrence of radiologic ASD, Oswestry disability index (ODI) scores, and revision rates. METHODS A total of 194 consecutive patients were contacted and encouraged to visit our hospital and to participate in our study. Radiologic ASD was evaluated at three motion segments: cephalad adjacent segment (first cephalad adjacent segment), one cephalad to cephalad adjacent segment (second cephalad adjacent segment), and caudal adjacent segment. Clinical outcomes were compared by ODI scores and revision rates. RESULTS In total, 147 of 194 (75.8%) patients were available for at least 10 years of radiologic and clinical follow-up. Adjacent segment degeneration (in first cephalad or caudal adjacent segment) was noted in 55.9% (33 of 59 patients) of the unilateral group and 72.7% (64 of 88 patients) of the bilateral group (p=.035). The occurrence of ASD in each first cephalad and caudal adjacent segment was not significantly different between groups but that in second cephalad adjacent segment was significantly different between groups (p=.004). Clinical outcomes according to ODI showed significant difference between groups (p=.016), especially when ODI scores were compared in patients with ASD (p=.004). CONCLUSIONS In a minimum 10-year follow-up retrospective study of posterolateral fusion for lumbar spinal stenosis and/or Grade 1 spondylolisthesis, unilateral pedicle screw instrumentation showed a lower rate of radiologic ASD, especially in second cephalad adjacent segment, and a better clinical outcome by ODI.
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Affiliation(s)
- Tae-Hwan Kim
- Department of Orthopedic Surgery, Yonsei University College of Medicine, CPO Box 8044, 50 Yonsei-Ro, Seodaemun-gu, Seoul 120-752, Korea
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Anterior corpectomy and reconstruction with titanium mesh cage and dynamic cervical plate for cervical spondylotic myelopathy in elderly osteoporosis patients. Arch Orthop Trauma Surg 2011; 131:1369-74. [PMID: 21573884 DOI: 10.1007/s00402-011-1317-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVE This retrospective study was to evaluate the relationship between osteoporosis and dynamic cervical plates in screw-plate or screw-bone interface of elderly cervical spondylotic myelopathy (CSM) patients. METHODS Retrospective study was conducted on elderly CSM patients, treated by anterior corpectomy and reconstruction with titanium mesh cages (TMC) and dynamic cervical plate between July 2004 and June 2007. All patients underwent bone mineral density (BMD) assessment in preoperation, and according to the osteoporosis degree they have been divided into two groups: moderate osteoporosis degree group and severe osteoporosis degree group. The clinical outcome [Japanese Orthopaedic Association score (JOA) and Visual Analogue Scale (VAS)], bone fusion assessment (CT mielogram), the change of titanium mesh cages and plate of cephalic screw-plate-angle (SPA) and cephalic endplate-plate-angle (EPA) of plain X-ray films were measured. RESULTS The mean JOA score and recovery rate were not different between the two groups (P > 0.05). There was no loss of sagittal alignment after surgery in any patient, and no significant difference between both groups on lordosis measurements (P > 0.05). Although there was a significant difference of the cage subsidence rate between the two groups (P < 0.001), all patients had favorable bone union and none required additional treatment. The average changes of SPA were greater in A group patients than in B group patients, while the variation of EPA was higher in B group patients than in A group patients (P < 0.001). CONCLUSIONS Despite the fact that there is a significant difference of the cage subsidence rate between the two groups no clinical outcome, nor sagittal alignment or fusion rate differences among groups was observed in elderly CSM patients.
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Massimiliano V, Giulio M. Six Level Cervico-Thoracic Circumferential Reconstruction: Report of the Second Case of the Literature. ADVANCES IN MINIMALLY INVASIVE SURGERY AND THERAPY FOR SPINE AND NERVES 2011; 108:187-90. [DOI: 10.1007/978-3-211-99370-5_28] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Heineck J, Haupt C, Werner K, Rammelt S, Zwipp H, Wilke HJ. Fracture models in the lumbar sheep spine: a biomechanical investigation. J Orthop Res 2010; 28:773-7. [PMID: 20058270 DOI: 10.1002/jor.21057] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The purpose of this study was to find out if a limited resection of the cranial vertebral body leaving the posterior wall intact is a sufficient model for AO type 3 fractures, or if additional resection of the posterior wall is necessary. In six, fresh-frozen, lumbar sheep spine specimens, the segmental stability was tested in three motion planes in a spine tester. First, the intact specimens were tested. Then, partial resection of the intervertebral disc L3/4 and resection of the cranial vertebral body of L4 was performed, leaving the posterior wall intact. This defect was tested without instrumentation and with a ventral monosegmental interlocking plate mounted. Then, the defect was extended to a total cranial resection, including the posterior wall, and the tests were subsequently repeated. The stability of both types of defects under the different conditions was compared. Without instrumentation, the total cranial resection showed significantly more ROM in flexion/extension and axial rotation than partial cranial resection. With the ventral interlocking plate mounted, the instability in total cranial resection was significantly higher in flexion/extension, with the relative relation even being increased. In axial rotation and lateral bending, the differences were equalized by the mounted plate. From a biomechanical point of view, total cranial resection including the posterior wall should be preferred as a sheep spine fracture model for AO type 3 fractures.
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Affiliation(s)
- Jan Heineck
- Klinik für Unfall-u. Wiederherstellungschirurgie, Universitätsklinik Carl Gustav Carus der Technischen Universität Dresden, Dresden, Germany.
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Cunningham BW, Atkinson BL, Hu N, Kikkawa J, Jenis L, Bryant J, Zamora PO, McAfee PC. Ceramic granules enhanced with B2A peptide for lumbar interbody spine fusion: an experimental study using an instrumented model in sheep. J Neurosurg Spine 2009; 10:300-7. [PMID: 19441986 DOI: 10.3171/2009.1.spine08565] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECT New generations of devices for spinal interbody fusion are expected to arise from the combined use of bioactive peptides and porous implants. The purpose of this dose-ranging study was to evaluate the fusion characteristics of porous ceramic granules (CGs) coated with the bioactive peptide B2A2-K-NS (B2A) by using a model of instrumented lumbar interbody spinal fusion in sheep. METHODS Instrumented spinal arthrodesis was performed in 40 operative sites in 20 adult sheep. In each animal, posterior instrumentation (pedicle screw and rod) and a polyetheretherketone cage were placed in 2 single-level procedures (L2-3 and L4-5). All cages were packed with graft material prior to implantation. The graft materials were prepared by mixing (1:1 vol/vol) CGs with or without a B2A coating and morselized autograft. Ceramic granules were coated with B2A at 50, 100, 300, and 600 microg/ml granules (50-B2A/CG, 100-B2A/CG, 300-B2A/CG, and 600-B2A/CG, respectively), resulting in 4 B2A-coated groups plus a control group (uncoated CGs). Graft material from each of these groups was implanted in 8 operative sites. Four months after arthrodesis, interbody fusion status was assessed with CT, and the interbody site was further evaluated with quantitative histomorphometry. RESULTS All B2A/CG groups had higher CT-confirmed interbody fusion rates compared with those in controls (CGs only). Seven of 8 sites were fused in the 50-B2A/CG, 100-B2A/CG, and 300-B2A/CG groups, whereas 5 of 8 sites were fused in the group that had received uncoated CGs. New woven and lamellar bone spanned the fusion sites with excellent osseointegration. There was no heterotopic ossification or other untoward events attributed to the use of B2A/CG in any group. Each B2A/CG treatment produced more new bone than that in the CG group. CONCLUSIONS Bioactive treatment with B2A effectively enhanced the fusion capacity of porous CGs. These findings suggest that B2A/CG may well represent a new generation of biomaterials for lumbar interbody fusion and indicate that additional studies are warranted.
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Affiliation(s)
- Bryan W Cunningham
- Orthopaedic Spinal Research Laboratory, St. Joseph Medical Center, Towson, MD, USA
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Long-term Biomechanical Stability and Clinical Improvement After Extended Multilevel Corpectomy and Circumferential Reconstruction of the Cervical Spine Using Titanium Mesh Cages. ACTA ACUST UNITED AC 2008; 21:165-74. [DOI: 10.1097/bsd.0b013e3180654205] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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The Effect of Arthrodesis, Implant Stiffness, and Time on the Canine Lumbar Spine. ACTA ACUST UNITED AC 2007; 20:549-59. [DOI: 10.1097/bsd.0b013e31804c98e5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lu J, Wu X, Li Y, Kong X. Surgical results of anterior corpectomy in the aged patients with cervical myelopathy. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2007; 17:129-35. [PMID: 17972117 DOI: 10.1007/s00586-007-0518-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 08/02/2007] [Accepted: 09/25/2007] [Indexed: 11/30/2022]
Abstract
Retrospective study on the results of anterior corpectomy for the treatment of cervical myelopathy in patients over 70 years old. To evaluate the surgical results of anterior corpectomy in aged patients with multilevel cervical myelopathy and to investigate the probable pathomechanism by radiographic study. There are few data focused on the surgical results and post-operative complications of anterior corpectomy in aged patients with cervical myelopathy. Twenty patients 70 years of age or older who underwent anterior corpectomy, titanium mesh cage (TMC) reconstruction and anterior plate fixation for the treatment of compressive cervical myelopathy were reviewed. The average age at the time of operation was 75 years. Neurologic deficits before and after surgery were assessed using a scoring system proposed by the Japanese Orthopedic Association (JOA Score). Clinical results and post-operative complications were compared with those of patients 69 years old or younger as a control. Pre-operative Radiologic evaluation of every patient consisted of anterior-posterior, lateral, bilateral oblique, flextion, and extension radiographs, computed tomography and magnetic resonance imaging of the cervical spine. Any factor causing spinal cord compression and the sign of cervical instability were recorded. Surgical-related complications occurred in seven patients in the aged group. The incidence of complications was 35% in the aged patient group and 9.7% in the control group respectively. Although the difference was striking, no statistical significance was found between the two groups. One patient died of respiratory failure resulting from pulmonary infection. The mortality rate was 5%. The pre-operative mean JOA score was 9.3 (from 3 to 14) in the aged patient group. Nineteen patients were followed at least 2 years and the mean JOA score was 13.4 (from 8 to 17). 68.4% of the aged patients achieved a good or excellent result. There was no statistical difference in the recovery rate of JOA score between the aged group (58.1%) and control group (67.0%). In the pre-operative radiographs, the incidence of cervical instability was much higher in the control group (32%) than in the aged group (5%) and multilevel cord compression caused by posterior disc space osteophytes was more common in the aged group. Anterior corpectomy combined with TMC fusion and plate fixation provides favorable neurologic recovery even in the patients over 70 years old. However, the incidence of surgical related complications shows a conspicuous increasing in the aged patients. Overcompensation mechanism for cervical instability is the probable cause of degenerative cervical spondylotic myelopathy in aged patients.
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Affiliation(s)
- Jun Lu
- Department of Orthopaedics, Medical School of Southeast University, ZhongDa Hospital, 87 DingJiaQiao, Nanjing 210009, China
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17
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Retrospective patient outcome evaluation after semi-rigid stabilization without fusion for degenerative lumbar instability. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY AND TRAUMATOLOGY 2007. [DOI: 10.1007/s00590-006-0186-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Goldhahn J, Neuhoff D, Schaeren S, Steiner B, Linke B, Aebi M, Schneider E. Osseointegration of hollow cylinder based spinal implants in normal and osteoporotic vertebrae: a sheep study. Arch Orthop Trauma Surg 2006; 126:554-61. [PMID: 16865404 DOI: 10.1007/s00402-006-0185-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Osteoporosis is not only responsible for an increased number of metaphyseal and spinal fractures but it also complicates their treatment. To prevent the initial loosening, we developed a new implant with an enlarged implant/bone interface based on the concept of perforated, hollow cylinders. We evaluated whether osseointegration of a hollow cylinder based implant takes place in normal or osteoporotic bone of sheep under functional loading conditions during anterior stabilization of the lumbar spine. MATERIALS AND METHODS Osseointegration of the cylinders and status of the fused segments (ventral corpectomy, replacement with iliac strut, and fixation with testing implant) were investigated in six osteoporotic (age 6.9 +/- 0.8 years, mean body weight 61.1 +/- 5.2 kg) and seven control sheep (age 6.1 +/- 0.2 years, mean body weight 64.9 +/- 5.7 kg). Osteoporosis was introduced using a combination protocol of ovariectomy, high-dose prednisone, calcium and phosphor reduced diet and movement restriction. Osseointegration was quantified using fluorescence and conventional histology; fusion status was determined using biomechanical testing of the stabilized segment in a six-degree-of-freedom loading device as well as with radiological and histological staging. RESULTS Intact bone trabeculae were found in 70% of all perforations without differences between the two groups (P = 0.26). Inside the cylinders, bone volume/total volume was significantly higher than in the control vertebra (50 +/- 16 vs. 28 +/- 13%) of the same animal (P<0.01), but significantly less (P<0.01) than in the near surrounding (60 +/- 21%). After biomechanical testing as described in Sect. "Materials and methods", seven spines (three healthy and four osteoporotic) were classified as completely fused and six (four healthy and two osteoporotic) as not fused after a 4-month observation time. All endplates were bridged with intact trabeculae in the histological slices. CONCLUSIONS The high number of perforations, filled with intact trabeculae, indicates an adequate fixation; bridging trabeculae between adjacent endplates and tricortical iliac struts in all vertebrae indicates that the anchorage is adequate to promote fusion in this animal model, even in the osteoporotic sheep.
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Affiliation(s)
- J Goldhahn
- AO Research Institute Davos, Davos, Switzerland.
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19
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Acosta FL, Aryan HE, Ames CP. Successful outcome of six-level cervicothoracic corpectomy and circumferential reconstruction: case report and review of literature on multilevel cervicothoracic corpectomy. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2006; 15 Suppl 5:670-4. [PMID: 16924551 PMCID: PMC1602202 DOI: 10.1007/s00586-006-0203-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 05/16/2006] [Accepted: 07/07/2006] [Indexed: 11/29/2022]
Abstract
The authors report the successful outcome of a six-level corpectomy across the cervico-thoracic spine with circumferential reconstruction in a patient with extensive osteomyelitis of the cervical and upper thoracic spine. To the authors’ knowledge, this is the first report of a corpectomy extending across six levels of the cervico-thoracic spine. Clinical relevance: the authors recommend anterior cage and plate-assisted reconstruction and additional posterior instrumentation using modern spinal surgical techniques and implants.
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Affiliation(s)
- Frank L Acosta
- Department of Neurological Surgery, University of California, 505 Parnassus Avenue, Moffitt Hospital M779, Box 0112, San Francisco, CA 94143, USA.
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20
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Abstract
STUDY DESIGN The mechanical stability of cross-linked and control spinal motion segments was evaluated using neutral zone, range of motion (ROM), and instability score metrics. OBJECTIVE To determine if exogenous cross-linking could increase the stability of spinal motion segments. SUMMARY OF BACKGROUND DATA The microstructure of the anulus fibrosus extracellular matrix can affect the stability of the intervertebral joint. Parallel testing in our laboratory has shown that exogenous cross-linking can improve the fatigue resistance of anulus fibrosus. METHODS There were 3 separate experimental protocols conducted. The first study used calf lumbar intervertebral joints randomly divided into a genipin cross-linked group and phosphate buffered saline-soaked controls. After 2 days of soaking, flexion-extension ramp cycles were applied to the specimens. The second study repeated the test protocol using 22 moderately and severely degenerated human lumbar intervertebral joints. The third experiment compared the effect of cross-linking treatment on human discs with known degrees of preexisting mechanical instability. Each data set was used to assess joint instability by 3 calculations: ROM, neutral zone, and an instability score. Joint instability for each data set was evaluated using 3 calculations: ROM, neutral zone, and a novel instability score. RESULTS These results show that cross-link augmentation can effectively reduce instability of intervertebral discs. The stabilizing effect was observed to be higher in the more mechanically unstable discs. However, cross-linking did not appear to affect the total range of sagittal motion. CONCLUSIONS By reducing the neutral zone, exogenous cross-linking may help combat the progression of instability in degenerative disc disease.
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Affiliation(s)
- Thomas P Hedman
- Institute for Spinal Disorders, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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21
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Abstract
Animal models for spinal fusion are essential for preclinical testing of new fusion methods and adjuncts. They allow for control of individual variables and quantification of outcome measures. Model characteristics are considered. Preclinical experiments to evaluate proof of concept, feasibility, and efficacy are generally studied in an orderly progression from smaller to larger animal models with an evolving cascade of evidence which has become known as the "burden of proof". Methods of fusion analysis include manual palpation, radiographs, computed tomography, histology, biomechanical testing, and molecular analysis. Models which have been developed in specific species are reviewed. This sets the stage for the interpretation of studies evaluating bone graft materials such as allograft, demineralized bone matrices, bone morphogenetic proteins, ceramics, and others with consideration of the variables affecting their success. As evidence accumulates, clinical trials and applications are defined.
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Affiliation(s)
- Inneke H Drespe
- Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, PO Box 208071, New Haven, CT 06520-8071, USA
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Freiherr von Salis-Soglio G, Scholz R, Seller K. Interkorporelle Metallimplantate („Cages“) bei lumbalen Spondylodesen. DER ORTHOPADE 2005; 34:1033-9. [PMID: 16075251 DOI: 10.1007/s00132-005-0840-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Over the last 15 years, interbody metal implants have become commonly used worldwide for lumbar interbody fusion. The so called "cages" are made of metal or absorbable materials. By using different surgical techniques, they can be implanted either regularly or via endoscopy. The published results on surgical techniques using cages for the lumbar spine show, in most cases and with or without additional instrumentation, rates of fusion of more than 90%. It seems that the use of osteoinductive substances (especially BMP) leads to even better results. Dorsoventral fusion with internal fixation and bone show the same rate of consolidation, but the advantages of cages are primarily in the maintenance of the distraction and the possibility of a single surgical procedure without additional instrumentation (including endoscopy), and in a lower donor side morbidity.
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Abstract
Fins incorporated into the design of a dynamic cervical spine implant have been employed to enhance axial load- bearing ability, yet their true biomechanical advantages, if any, have not been defined. Therefore, the goal of this study was to assess the biomechanical and axial load-bearing contributions of the fin components of the DOC ventral cervical stabilization system. Eighteen fresh cadaveric thoracic vertebrae (T1-T3) were obtained. Three test conditions were devised and studied: Condition A (DOC implants with fins were placed against the superior endplate and bone screws were not inserted); Condition B (DOC implant without fins was placed and bone screws were inserted); and Condition C (DOC implant with fins were placed against the superior endplate and bone screws were inserted). Specimens were tested by applying a pure axial compressive load to the superior platform of the DOC construct, and load-displacement data were collected. Condition C specimens had the greatest stiffness (459 +/- 80 N/mm) and yield load (526 +/- 168 N). Condition A specimens were the least stiff (266 +/- 53 N/mm), and had the smallest yield loads (180 +/- 54 N). The yield load of condition A plus condition B was approximately equal to that of condition C, with condition A contributing about one-third and condition B contributing two-thirds of the overall load-bearing capacity. Although the screws alone contributed to a substantial portion of axial load-bearing ability, the addition of the fins further increased load-bearing capabilities.
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Affiliation(s)
- Byung Ho Jin
- Department of Neurosurgery, Yongdong Severance Hospital, Yonsei University College of Medicine, 146-92 Dogok-dong, Kangnam-gu, Seoul 135- 720, Korea.
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Schmidt R, Richter M, Claes L, Puhl W, Wilke HJ. Limitations of the cervical porcine spine in evaluating spinal implants in comparison with human cervical spinal segments: a biomechanical in vitro comparison of porcine and human cervical spine specimens with different instrumentation techniques. Spine (Phila Pa 1976) 2005; 30:1275-82. [PMID: 15928552 DOI: 10.1097/01.brs.0000164096.71261.c2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Porcine and human cervical spine specimens were in vitro biomechanically compared with different instrumentation techniques. OBJECTIVES To evaluate whether subaxial porcine cervical spines are a valid model for implant testing in a single level corpectomy. SUMMARY OF BACKGROUND DATA Biomechanical in vitro tests are widely used for implant tests, mainly with human spine specimens. The availability of human cadavers is limited and the properties of the specimen regarding age, bone mineral density, and grade of degenerative changes is inhomogeneous. METHODS Six porcine and six human cervical specimens were loaded nondestructively with pure moments: 1) in an intact state; 2) after a corpectomy of C5 and substitution by a cage with integrated force sensor; 3) after additional instrumentation with a posterior screw and rod system with: a) lateral mass and b) pedicle screws; 4) after instrumentation with an anterior plate; and 5) with a circumferential instrumentation. The unconstrained motion and the axial loads occurring in the corpectomy gap were measured, as well as the bone mineral density of the specimen before testing. RESULTS The range of motion in the intact state, as well as for the different instrumentations, was comparable for flexion-extension. In lateral bending and axial rotation, marked differences in the intact state as well as for pedicle screw instrumentations occurred. CONCLUSIONS The subaxial porcine cervical spine is a potential model in flexion-extension because of its biomechanical similarity. For lateral bending and axial rotation, the marked differences severly restrict the comparability.
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Affiliation(s)
- René Schmidt
- Department of Orthopedics and SCI, University of Ulm, Ulm, Germany.
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25
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Jea A, Vanni S. Anterior correction of cervical spine lordosis using an adjustable depth tap: technical note. ACTA ACUST UNITED AC 2005; 18:178-81. [PMID: 15800437 DOI: 10.1097/01.bsd.0000154451.36450.df] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE In cases of multilevel anterior cervical spine decompression where intervening vertebral bodies need to be incorporated into the anterior plate construct, it may be difficult to apply the plate flush against the entire anterior cortical surface of the spine segment. Some have suggested using the levering property of bicortical screws to "pull" the body against the plate. Others have recommended contouring the anterior cervical plate with a plate bender. The objective of this work was to describe a novel technique using the adjustable depth tap provided in the Atlantis plating system for achieving cervical spine alignment against the lordotic plate after multilevel anterior decompression. METHODS We describe an illustrative case of a 14-year-old girl with complex cervical spine fractures after trauma. We used the 4.0-mm adjustable depth tap in the Atlantis plating system to lever the C4 body against the premachined lordotic plate. RESULTS Cervical lordosis and anterior cervical plate placement were accomplished after multilevel anterior cervical decompression with the use of an adjustable depth tap. CONCLUSIONS Bicortical screw placement and plate bending have drawbacks in trying to apply the anterior cervical plate firmly to the anterior surface of the cervical spine. We describe a new and safe technique of using an adjustable depth tap for achieving that same goal without any obvious drawbacks.
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Affiliation(s)
- Andrew Jea
- Department of Neurological Surgery, University of Miami School of Medicine, Miami, FL 33136, USA
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26
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Vaccaro AR, Patel T, Fischgrund J, Anderson DG, Truumees E, Herkowitz H, Phillips F, Hilibrand A, Albert TJ. A 2-year follow-up pilot study evaluating the safety and efficacy of op-1 putty (rhbmp-7) as an adjunct to iliac crest autograft in posterolateral lumbar fusions. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2005; 14:623-9. [PMID: 15672240 PMCID: PMC3489216 DOI: 10.1007/s00586-004-0845-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2004] [Accepted: 10/15/2004] [Indexed: 10/25/2022]
Abstract
The ability of bone morphogenetic proteins (BMPs) to induce bone formation has led to a multitude of investigations into their use as bone graft substitutes in spinal surgery. The purpose of this multi-center clinical pilot study was to evaluate the safety and efficacy of BMP-7 (osteogenic protein 1, OP-1), in the form of a putty, combined with autograft for intertransverse process fusion of the lumbar spine in patients with symptomatic spinal stenosis and degenerative spondylolisthesis following spinal decompression. Twelve patients with spinal stenosis and degenerative lumbar spondylolisthesis underwent a laminectomy and partial or complete medial facetectomy as required for decompression of the neural elements, followed by an intertransverse process fusion by placing iliac crest autograft and OP-1 putty between the decorticated transverse processes. No instrumentation was used. Patients were followed clinically using the Oswestry scale and SF-36 outcome forms, and radiographically using static and dynamic radiographs to assess their fusion status over a 2-year period. Independent and blinded radiologists assessed the films for the presence of bridging bone between the transverse processes and measured translation and angulation on dynamic films using digital calipers. Radiographic outcome was compared to a historical control (autograft alone fusion without instrumentation for the treatment of degenerative spondylolisthesis). All adverse events were recorded prospectively. The results showed eight of the nine evaluable patients (89%) obtained at least a 20% improvement in their preoperative Oswestry score, while five of ten patients (50%) with radiographic follow-up achieved a solid fusion by the criteria used in this study. Bridging bone on the anteroposterior film was observed in seven of the ten patients (70%). No systemic toxicity, ectopic bone formation, recurrent stenosis or other adverse events related to the OP-1 putty implant were observed. A successful fusion was observed in slightly over half the patients in this study, using stringent criteria without adjunctive spinal instrumentation. This study did not demonstrate the statistical superiority of OP-1 combined with autograft over an autograft alone historical control, in which the fusion rate was 45%. There were no adverse events related to the OP-1 putty implant in this study, which supports findings in other studies suggesting the safety of bone morphogenetic proteins in spinal surgery.
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Affiliation(s)
- Alexander R Vaccaro
- Orthopaedic Surgery, Thomas Jefferson University and the Rothman Institute, Philadelphia, PA, USA.
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27
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Sevki K, Mehmet T, Ufuk T, Azmi H, Mercan S, Erkal B. Results of surgical treatment for degenerative cervical myelopathy: anterior cervical corpectomy and stabilization. Spine (Phila Pa 1976) 2004; 29:2493-500. [PMID: 15543060 DOI: 10.1097/01.brs.0000145412.93407.c3] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN This retrospective study involves 26 patients with degenerative cervical myelopathy who were surgically treated by anterior corpectomy, titanium mesh cage (TMC) filled with autogenous bone, and anterior plate +/- posterolateral plate and fusion. OBJECTIVES This study was conducted to determine the indications, efficacy, and complication rate associated with performing corpectomy to achieve anterior decompression of neural elements or for removing anterior lesions. SUMMARY OF BACKGROUND DATA This retrospective study involves patients with degenerative cervical myelopathy who were surgically treated by > or =2-level anterior corpectomy, TMC filled with autogenous bone, and anterior plate +/- posterolateral plate and fusion. The purpose was to evaluate and compare the results in terms of neurologic recovery and function and effectivity of TMC as a structural support. METHODS Twenty-six patients with degenerative cervical myelopathy who had surgical treatment and average 30 months (range, 24-52 months) follow up were included. The mean age was 64.9 years (range, 55-74 years) and average period between myelopathic symptoms and surgery was 2.8 years (range, 6 months-5 years). Preoperative evaluation of every patient consisted of anterior-posterior, lateral, bilateral oblique, flexion, and extension radiographs, computed tomography reconstructions and magnetic resonance imaging of the cervical spine, Doppler ultrasound of the carotid arteries, vertebral artery magnetic resonance angiography, neurologic examination, and electromyography. Degree of pre- and postoperative myelopathy was determined according to the scoring systems developed by Nurick and Japanese Orthopedic Association (JOA). Twelve patients had a mild balance problem and difficulty while walking but were able to perform their daily activities. Fourteen patients had spastic quadriparesis ambulating on either crutches or with wheelchairs. Of these, 11 experienced bladder disturbance as well. Surgical treatment in 18 patients consisted of anterior decompressive corpectomy, structural TMC, and anterior plate stabilization in 14 patients who had 2-level corpectomy. Posterior plate stabilization without laminectomy was added to this procedure in another 4 patients who had 3- or more level corpectomy. The remaining 8 patients had first laminectomy and posterolateral plate, then anterior corpectomy, TMC, and anterior plate on the same stage. Corpectomy levels were between C3 and T1, and anterior corpectomy, structural TMC, and anterior plating was the procedure that all patients had in common. RESULTS Mean sagittal Cobb angle (C2-C7) was 9 degrees (range, 0-23 degrees) before surgery, 17.1 degrees (range, 11-22 degrees) on the third postoperative month, and 16.9 degrees (range, 10-22 degrees) at last follow-up. The difference in sagittal alignment on the third month and last follow up was not statistically significant (P > 0.05). Average preoperative Nurick score was 3.5 (range, 2-5) and JOA score was 7 (range, 1-14). Major and statistically significant neurologic recovery was within the first 3 months, and average Nurick and JOA scores at 3 months were 2 (range, 0-3) and 11 (range, 8-17) (P < 0.001), respectively. All patients had improved neurologic status at final follow up. As confirmed by plain radiographs and computed tomography reconstructions, solid fusion was achieved across the TMC with no settling or migration, and we had no implant-related complication or failure. As major complications, 1 (3.8%) early deep posterior infection developed but responded to early debridement and antibiotics. Also, 3 patients (11.5%) had transient C5 nerve root injury. At final follow up, all patients were able to ambulate without support and maintain their daily activities. CONCLUSIONS Anterior decompression provides good neurologic recovery in patients with degenerative cervical myelopathy. TMC provides good structural support, and solid fusion can be achieved with TMC and anterior plate (for < or =2-level corpectomy) and/or posterior plate (> or =3-level corpectomy). There is increased risk of C5 nerve root injury when first laminectomy and posterolateral plate stabilization are performed.
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Affiliation(s)
- Kabak Sevki
- Erciyes University, Medical Faculty, Orthopaedics and Traumatology Department, Kayseri, Turkey.
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28
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Kruyt MC, van Gaalen SM, Oner FC, Verbout AJ, de Bruijn JD, Dhert WJA. Bone tissue engineering and spinal fusion: the potential of hybrid constructs by combining osteoprogenitor cells and scaffolds. Biomaterials 2004; 25:1463-73. [PMID: 14697849 DOI: 10.1016/s0142-9612(03)00490-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In this paper, we discuss the current knowledge and achievements on bone tissue engineering with regard to spinal fusion and highlight the technique that employs hybrid constructs of porous scaffolds with bone marrow stromal cells. These hybrid constructs potentially function in a way comparable to the present golden standard, the autologous bone graft, which comprises besides many other factors, a construct of an optimal biological scaffold with osteoprogenitor cells. However, little is known about the role of the cells in autologous grafts, and especially survival of these cells is questionable. Therefore, more research will be needed to establish a level of functioning of hybrid constructs to equal the autologous bone graft. Spinal fusion models are relevant because of the increasing demand for graft material related to this procedure. Furthermore, they offer a very challenging environment to further investigate the technique. Anterior and posterolateral animal models of spinal fusion are discussed together with recommendations on design and assessment of outcome parameters.
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Affiliation(s)
- M C Kruyt
- Department of Orthopaedics, University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, Netherlands.
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29
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Vaccaro AR, Patel T, Fischgrund J, Anderson DG, Truumees E, Herkowitz H, Phillips F, Hilibrand A, Albert TJ. A pilot safety and efficacy study of OP-1 putty (rhBMP-7) as an adjunct to iliac crest autograft in posterolateral lumbar fusions. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2003; 12:495-500. [PMID: 12908103 PMCID: PMC3468017 DOI: 10.1007/s00586-003-0561-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Revised: 03/14/2003] [Accepted: 03/26/2003] [Indexed: 10/26/2022]
Abstract
The ability of bone morphogenetic proteins (BMPs) to induce bone formation has led to an increasing interest in the potential for their use in fusion surgery. The purpose of this multi-center clinical pilot study was to evaluate the safety of one such BMP-osteogenic protein 1, in the form of OP-1 putty-combined with autograft for intertransverse process fusion of the lumbar spine in patients with symptomatic spinal stenosis and degenerative spondylolisthesis following spinal decompression. Twelve patients with spinal stenosis and degenerative lumbar spondylolisthesis underwent laminectomy and partial or complete medial facetectomy as required for decompression of the neural elements followed by intertransverse process fusion by placing iliac crest autograft and OP-1 putty between the decorticated transverse processes. No instrumentation was used. Patients were followed clinically using the Oswestry scale and radiographically using static and dynamic radiographs to assess their fusion status. Independent and blinded radiologists assessed the films for the presence of bridging bone between the transverse processes and measured translation and angulation on dynamic films using digital calipers. In addition to bridging bone, less than or equal to 5 degrees of angular motion and less than or equal to 2 mm of translation were required to classify the patients as successfully fused, as per the definition of successful fusion provided by the FDA for use in clinical trials involving investigational devices to attain spinal fusion. Radiographic outcome was compared to a historical control (autograft alone fusion without instrumentation for the treatment of degenerative spondylolisthesis). All adverse events were recorded prospectively. The results showed 9 of the 12 patients (75%) obtained at least a 20% improvement in their preoperative Oswestry score, while 6 of 11 patients (55%) with radiographic follow-up achieved a solid fusion by the criteria used in this study. Bridging bone on the anteroposterior film was observed in 10 of the 11 patients (91%). No systemic toxicity, ectopic bone formation, recurrent stenosis or other adverse events related to the OP-1 putty implant were observed. A successful fusion was observed in slightly over half the patients in this study, using stringent criteria without adjunctive spinal instrumentation. This study did not demonstrate the superiority of OP-1 combined with autograft over an autograft alone historical control, in which the fusion rate was approximately 45%. The lack of adverse events related to the OP-1 putty implant in this study is in agreement with other studies supporting the safety of bone morphogenetic proteins in spinal surgery.
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Affiliation(s)
- Alexander R Vaccaro
- Department of Orthopaedic Surgery, Thomas Jefferson University, The Rothman Institute, 925 Chestnut St, 5th Floor, Philadelphia, PA 19107, USA.
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30
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Schlenk RP, Stewart T, Benzel EC. The biomechanics of iatrogenic spinal destabilization and implant failure. Neurosurg Focus 2003; 15:E2. [PMID: 15347220 DOI: 10.3171/foc.2003.15.3.2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Revision spinal surgery is usually indicated in cases of persistent or recurrent symptoms related to neural compression, spinal deformity, or construct failure. An understanding of fundamental biomechanical principles of both spinal decompression and reconstructive strategies is essential to avoid unnecessary subsequent spinal operations.
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Affiliation(s)
- Richard P Schlenk
- Cleveland Clinic Spine Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
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31
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Chen CS, Cheng CK, Liu CL. A biomechanical comparison of posterolateral fusion and posterior fusion in the lumbar spine. JOURNAL OF SPINAL DISORDERS & TECHNIQUES 2002; 15:53-63. [PMID: 11891453 DOI: 10.1097/00024720-200202000-00010] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Late postoperative complications occurred after posterior fusion and posterolateral fusion as a result of biomechanical alterations. The stress change between the two fusion procedures has not been well reported. To differentiate the biomechanical alteration that occurs with posterior fusion and posterolateral fusion of the lumbar spine, the load sharing of the vertebrae, disc, facet joint, bone graft, and the range of motion were computed in a finite element model. Five finite element models, including the intact lumber spine, posterior fusion, posterior fusion with implant, posterolateral fusion, and posterolateral fusion with implant, were created for stress analysis. The finite element model estimated that the differences between these two fusion procedures were within 7% in stress of the adjacent disc, 3% in force of the facet joint above the fusion mass, and 5% in the range of motion. However, the stress of the pedicle in posterolateral fusion without an implant was at most two times greater than that in the intact lumbar spine under lateral bending. The stress of pars interarticularis in posterior fusion without an implant was also at most two times greater than that in the intact lumbar spine under lateral bending. After the implant was added, the discrepancy between the two fusion procedures decreased but still remained a relatively large difference. Therefore, the largest changes of posterior fusion and posterolateral fusion were in the pars interarticularis and pedicle, respectively.
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Affiliation(s)
- Chen-Sheng Chen
- Institute of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
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Pape D, Fritsch E, Kelm J, Müller K, Georg T, Kohn D, Adam F. Lumbosacral stability of consolidated anteroposterior fusion after instrumentation removal determined by roentgen stereophotogrammetric analysis and direct surgical exploration. Spine (Phila Pa 1976) 2002; 27:269-74. [PMID: 11805690 DOI: 10.1097/00007632-200202010-00014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN The intervertebral stability of bony consolidated anteroposterior lumbosacral spondylodesis is evaluated by roentgen stereophotogrammetric analysis and direct surgical exploration before and after removal of the internal fixator. OBJECTIVES To determine the remaining in vivo stability of spinal arthrodesis solely retained by a bony integrated carbon fiber cage. SUMMARY OF BACKGROUND DATA Roentgen stereophotogrammetric analysis studies on posterolateral lumbar fusions demonstrate primary spinal stability after additional dorsal instrumentation, which is retained during bony fusion healing. Animal models show a persistent stabilizing effect of the fixator despite the presence of bony fusion. Although direct surgical inspection is the most reliable method to evaluate fused vertebrae, roentgen stereophotogrammetric analysis has also proven to be a highly accurate method to evaluate spinal stability. METHODS In 10 patients lumbosacral fusion was performed using carbon interbody implants and an internal fixator. Ten months after initial surgery (range 7-15 months) the internal fixation was removed to reduce local soft tissue impingement as soon as bony fusion was achieved. Fusion site exploration in the course of instrumentation removal was performed by applying distraction, compression, and torque to the grafted area under fluoroscopic control. Any motion indicated a pseudarthrosis. Lumbosacral stability was evaluated by serial roentgen stereophotogrammetric analysis after fusion and after instrumentation removal. RESULTS During instrumentation removal the mechanical stress test under fluoroscopic control did not indicate pseudarthrosis. After instrumentation removal, roentgen stereophotogrammetric analysis measurements revealed a nonsignificant increase in lumbosacral micromotions within the fused segment with 0.14, 0.31, and 0.44 mm in the transverse, vertical, and sagittal axes, respectively. CONCLUSIONS The internal fixator could be removed without endangering the stability of the fusion. Direct surgical exploration confirmed the adequacy of roentgen stereophotogrammetric analysis as a reliable in vivo method to evaluate lumbosacral stability after anteroposterior fusion.
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Affiliation(s)
- Dietrich Pape
- Institute for Medical Biometrics, Epidemiology and Medical Informatics, University of Saarland, Homburg/Saar, Germany.
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Wang JL, Panjabi MM, Isomi T. The role of bone graft force in stabilizing the multilevel anterior cervical spine plate system. Spine (Phila Pa 1976) 2000; 25:1649-54. [PMID: 10870140 DOI: 10.1097/00007632-200007010-00008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN The role of bone graft force in stabilizing an instrumented cervical spine was evaluated for one-level and three-level corpectomy models using in vitro experiments. OBJECTIVES To investigate the role of bone graft force in enhancing stability of anterior cervical plate, and to study effects of fatigue loading. SUMMARY OF BACKGROUND DATA The anterior cervical plate system is used widely in stabilizing the cervical spine after spinal corpectomy and grafting. Many factors such as applied screw torque, screw pullout force, plate strength, plate geometry, and type of bone graft have been studied. However, the role of bone graft in stabilizing the anterior plate system has not been explored. METHODS Two models (one-level and three-level) incorporating corpectomy, strut graft, and anterior plate were constructed from eight human spine specimens (C2-T1). The flexibility of an intact specimen and two constructs with graft forces of 0 N and 100 N was determined. A flexibility test, simulating physiologic loads, consisted of pure moments of flexion, extension, lateral bending, and axial torques up to 1 Nm. For each moment, range of motion and neutral zone were determined. The stability potential index was defined as the decrease in motion caused by instrumentation, as compared with intact motion. A larger stability potential index indicates a more stable spinal construct. Repeated measures analysis of variance was used to determine the significant changes. RESULTS In both models, bone graft force increased during extension, decreased during flexion, and showed minor changes during axial torsion and lateral bending. Higher bone graft force increased stability potential index-neutral zone and stability potential index-range of motion in the three-level model in all directions, but only in flexion-extension in the one-level model. Fatigue loading decreased bone graft force to a greater extent in the three-level model. CONCLUSIONS In the corpectomy-graft-anterior-plate model, graft force decreased in flexion and increased in extension. Higher graft force increased and fatigue decreased stability of the spinal construct in the three-level model.
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Affiliation(s)
- J L Wang
- Biomechanics Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut, USA
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Isomi T, Panjabi MM, Wang JL, Vaccaro AR, Garfin SR, Patel T. Stabilizing potential of anterior cervical plates in multilevel corpectomies. Spine (Phila Pa 1976) 1999; 24:2219-23. [PMID: 10562987 DOI: 10.1097/00007632-199911010-00008] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN An in vitro investigation of three-dimensional kinematics of cervical spine models of one- and three-level corpectomy with anterior plate fixation. OBJECTIVES To evaluate the capability of an anterior plate to stabilize the reconstructed cervical spine under simulated physiologic motions, and to study the effects of fatigue loading. SUMMARY OF BACKGROUND DATA Clinical studies have found high failure rates of multilevel anterior cervical plate fusions, indicating suboptimal stabilization. However, no biomechanical studies have been done to investigate the stabilizing capabilities of long-plate instrumentations in corpectomy models. METHODS Seven fresh human cadaveric cervical spine specimens (C2-T1) were used. Flexibility tests consisted of flexion, extension, and bilateral torsion, and lateral bending, each with a pure moment of 0.25, 0.5, 0.75, and 1.0 Nm. Stabilizing potential indices [(MotionIntact-MotionInstrumented)/MotionIntact] for ranges of motion and neutral zones obtained from the flexibility tests, were measured when the specimen was intact and after one-level (C5) and three-level (C4, C5, and C6) corpectomies and anterior plate stabilizations). The stabilizing potential indices were re-measured after a 1000-cycle fatigue loading (1 Nm flexion and extension moments at C5 vertebra at 0.14 Hz). RESULTS The differences in stabilizing potential indices of range of motion and neutral zone between one-level and three-level plates were not significant before fatigue. However, after fatigue, the stabilizing potential indices significantly decreased (P < 0.05) for the three-level model, but not for the one-level plate model. CONCLUSIONS The capability of an anterior cervical plate to stabilize the spine after three-level corpectomy was significantly reduced with fatigue loading.
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Affiliation(s)
- T Isomi
- Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut, USA
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Kanayama M, Ng JT, Cunningham BW, Abumi K, Kaneda K, McAfee PC. Biomechanical analysis of anterior versus circumferential spinal reconstruction for various anatomic stages of tumor lesions. Spine (Phila Pa 1976) 1999; 24:445-50. [PMID: 10084181 DOI: 10.1097/00007632-199903010-00007] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Spinal reconstruction procedures for metastasis evaluated biomechanically using human cadaver specimens. OBJECTIVE To investigate the stiffness of anterior versus circumferential spinal reconstructions for different anatomic stages of tumor lesions. SUMMARY OF BACKGROUND DATA Metastatic tumors predominantly involve the vertebral bodies. Although anterior instrumentation and strut grafts provide excellent stability, it remains unclear to what extent vertebral destruction requires anterior reconstructions alone versus combined anterior and posterior procedures. METHODS Ten human cadaveric thoracolumbar spines were used. The L1 vertebral body and posterior elements were resected sequentially based on Weinstein's anatomic zone classification for tumor lesions. Anterior reconstruction was performed between T12 and L2 using an iliac strut graft and the Kaneda SR system (AcroMed, Cleveland, OH). For circumferential reconstruction, the Cotrel-Dubousset hook and rod system was combined with the anterior reconstruction procedure. Experimental groups included the intact condition and five reconstruction stages: anterior reconstructions for corpectomy, subtotal and total spondylectomies, and circumferential reconstructions for subtotal and total spondylectomies. Nondestructive biomechanical testing was performed under four different loading modes. RESULTS All the reconstruction groups except anterior instrumentation alone for total spondylectomy returned stiffness to a level equivalent or higher to that of the intact spine. There were no statistical differences observed between anterior and circumferential reconstruction for subtotal spondylectomy. Anterior instrumentation alone for total spondylectomy did not restore stiffness to the intact level, and demonstrated significantly lower stiffness than that of circumferential reconstruction. CONCLUSIONS For corpectomy or subtotal spondylectomy, anterior reconstruction alone can provide stiffness equivalent to circumferential reconstruction. However, total spondylectomy significantly reduces the anterior reconstruction stiffness, suggesting the need for combined anterior and posterior procedures.
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Affiliation(s)
- M Kanayama
- Department of Orthopaedic Surgery, Hokkaido University School of Medicine, Sapporo, Japan.
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