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Ramos MRD, Mendoza CJP, Yumol JV, Joson RS, Ver MLP, Ver MR. Multilevel, Percutaneous Posterior Cervical Interfacet Distraction and Fusion for Cervical Spondylotic Radiculopathy: Clinical and Radiographic Outcomes. Spine (Phila Pa 1976) 2021; 46:E1146-E1154. [PMID: 34033597 DOI: 10.1097/brs.0000000000004129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Retrospective review of patients who underwent multilevel posterior cervical interfacet distraction and fusion (PCIDF) using cages for cervical spondylotic radiculopathy (CSR). OBJECTIVE To determine clinical and radiographic outcomes following multilevel PCIDF. SUMMARY OF BACKGROUND DATA Anterior cervical discectomy and fusion has long been the standard of treatment for CSR. Advancements in surgery have employed minimally invasive techniques such as endoscopic discectomy, foraminotomy, and PCIDF. Studies on single-level PCIDF have reported good clinical outcomes, short hospital stays, and rare complications, but its application in multilevel disease is still evolving. METHODS Patients with CSR and confirmed radiologic evidence of multilevel foraminal stenosis without central canal stenosis were reviewed. Two-year outcomes of multilevel PCIDF included Neck Disability Index, neck and arm Visual Analogue Scale (VAS), radiographic cervical alignment parameters, evidence of fusion, and incidence of adjacent segment degeneration were compared at different time points. RESULTS Thirty patients (mean age 54.6 ± 8.3) were included in the study with an average of 3.4 ± 0.8 levels treated. Mean surgical duration and intraoperative blood loss was 143.2 ± 69.7 minutes and 27.7 ± 28.7 mL, respectively, with an average length of stay at 1.8 ± 1.5 days. Neck Disability Index, VAS-neck, and VAS-arm all significantly improved at 2 weeks (P < 0.001) and was maintained until 2 years postoperatively. A significant decrease in segmental and C2-C7 lordosis, with a corresponding increase in sagittal vertical axis, was observed at 3 months postoperatively (P < 0.001) but did not deteriorate further on subsequent visits. Successful fusion was achieved in 90% of patients after 2 years. There was a 13.3% incidence of adjacent segment degeneration in the study cohort and one perioperative complication (3.3%). CONCLUSION Our study suggests that multilevel PCIDF is safe and effective for CSR caused by foraminal stenosis. However, its potential to cause kyphosis and clinical impact on global sagittal alignment requires further scrutiny and long-term evaluation.Level of Evidence: 4.
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Affiliation(s)
| | | | | | | | - Mikhail Lew Perez Ver
- Institute of Orthopaedics and Sports Medicine, St. Luke's Medical Center, Quezon City, Philippines
| | - Mario Ratio Ver
- Institute of Orthopaedics and Sports Medicine, St. Luke's Medical Center, Quezon City, Philippines
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Pereira BDA, Heller JE, Lehrman JN, Sawa AGU, Kelly BP. Biomechanics of Circumferential Cervical Fixation Using Posterior Facet Cages: A Cadaveric Study. Neurospine 2021; 18:188-196. [PMID: 33819945 PMCID: PMC8021845 DOI: 10.14245/ns.2040552.276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/28/2020] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE Anterior cervical discectomy and fusion (ACDF) is a common procedure for the treatment of cervical disease. Circumferential procedures are options for multilevel pathology. Potential complications of multilevel anterior procedures are dysphagia and pseudarthrosis, whereas potential complications of posterior surgery include development of cervical kyphosis and postoperative chronic neck pain. The addition of posterior cervical cages (PCCs) to multilevel ACDF is a minimally invasive option to perform circumferential fusion. This study evaluated the biomechanical performance of 3-level circumferential fusion with PCCs as supplemental fixation to anteriorly placed allografts, with and without anterior plate fixation. METHODS Nondestructive flexibility tests (1.5 Nm) performed on 6 cervical C2-7 cadaveric specimens intact and after discectomy (C3-6) in 3 instrumented conditions: allograft with anterior plate (G+P), PCC with allograft and plate (PCC+G+P), and PCC with allograft alone (PCC+G). Range of motion (ROM) data were analyzed using 1-way repeated-measures analysis of variance. RESULTS All instrumented conditions resulted in significantly reduced ROM at the 3 instrumented levels (C3-6) compared to intact spinal segments in flexion, extension, lateral bending, and axial rotation (p < 0.001). No significant difference in ROM was found between G+P and PCC+G+P conditions or between G+P and PCC+G conditions, indicating similar stability between these conditions in all directions of motion. CONCLUSION All instrumented conditions resulted in considerable reduction in ROM. The added reduction in ROM through the addition of PCCs did not reach statistical significance. Circumferential fusion with anterior allograft, without plate and with PCCs, has comparable stability to ACDF with allograft and plate.
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Affiliation(s)
- Bernardo de Andrada Pereira
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | | | - Jennifer N Lehrman
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Anna G U Sawa
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Brian P Kelly
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
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Effectiveness of cervical zero profile integrated cage with and without supplemental posterior Interfacet stabilization. Clin Biomech (Bristol, Avon) 2020; 78:105078. [PMID: 32585556 PMCID: PMC7430527 DOI: 10.1016/j.clinbiomech.2020.105078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 04/28/2020] [Accepted: 06/05/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Conditions requiring cervical decompression and stabilization are commonly treated using anterior cervical discectomy and fusion using an anterior cage-plate construct. Anterior zero profile integrated cages are an alternative to a cage-plate construct, but literature suggests they may result in less motion reduction. Interfacet cages may improve integrated cage stability. This study evaluated the motion reduction of integrated cages with and without supplemental interfacet fixation. Motion reduction of integrated cages were also compared to published cage-plate results. METHODS Seven cadaveric (C2-T1) spines were tested in flexion-extension, lateral bending, and rotation. Specimens were tested: 1) intact, 2) C6-C7 integrated cage, 3) C6-C7 integrated cage + interfacet cages, 4) additional integrated cages at C3-C4 and C4-C5, 5) C3-C4, C4-C5 and C6-C7 integrated cages + interfacet cages. Motion, lordosis, disc and neuroforaminal height were assessed. FINDINGS Integrated cage at C6-C7 decreased flexion-extension by 37% (P = .06) and C3-C5 by 54% (P < .01). Integrated + interfacet cages decreased motion by 89% and 86% compared to intact (P < .05). Integrated cages increased lordosis at C4-C5 and C6-C7 (P < .01). Integrated + interfacet cages returned C3-C5 lordosis to intact values, while C6-C7 remained more lordotic (P = .02). Compared to intact, neuroforaminal height increased after integrated cages at C3-C5 (P ≤ .01) and at all levels after interfacet cages (P < .01). INTERPRETATION Anterior integrated cages provides less stability than traditional cage-plate constructs while supplemental interfacet cages improve stabilization. Integrated cages provide more lordosis at caudal levels and increase neuroforaminal height more at cranial levels. After interfacet cages, posterior disc height and neuroforaminal height increased more at the caudal segments.
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Cofano F, Sciarrone GJ, Pecoraro MF, Marengo N, Ajello M, Penner F, Petrone S, Ducati A, Zenga F, Musso C, Garbossa D. Cervical Interfacet Spacers to Promote Indirect Decompression and Enhance Fusion in Degenerative Spine: A Review. World Neurosurg 2019; 126:447-452. [PMID: 30904796 DOI: 10.1016/j.wneu.2019.03.114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/09/2019] [Accepted: 03/11/2019] [Indexed: 11/26/2022]
Abstract
BACKGROUND Among the posterior techniques, the use of cervical interfacet spacers (CISs) represents a promising technology whose potentialities are still being studied. The purpose of the present review was to assess the available data on CISs. METHODS A search on PubMed was performed. The search terms were "cervical interfacet spacers," "facet spacers," "DTRAX facet system," "Goel facet spacer," "pseudarthrosis," "cervical lordosis," "iatrogenic kyphosis," "cervical foraminal decompression," "cervical biomechanics," "atlantoaxial instability," and "subaxial instability." RESULTS Mechanical studies have shown that stand-alone CISs promoted stiffness in all directions, except for extension. Foraminal distraction was recorded in 86% of the cases. Clinical studies have shown that the use of CISs could promote successful arthrodesis, given the large surface area affected by fusion and decreasing the need for autografts. The effectiveness for the treatment of radiculopathy has been confirmed by several clinical studies. In a series of 154 levels of implanted CISs, no evidence of significant loss of cervical lordosis was identified. CISs could help in enhancing fusion in C1-C2 fixation. CONCLUSIONS Biomechanical studies on specimens showed a positive trend in increasing stiffness of the cervical spine, despite some controversial results. In clinical studies, facet distraction was shown to be a safe and valid option for clinical indirect decompression, although longer follow-up is required for confirmation. No evidence of the loss of cervical lordosis has been recorded. The long-term effects and CIS use in revision procedures as adjuvant implants to treat pseudarthrosis or atlantoaxial instability are currently under investigation, and further studies are needed.
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Affiliation(s)
- Fabio Cofano
- Division of Neurosurgery, Department of Neuroscience, University of Turin, Turin, Italy.
| | | | | | - Nicola Marengo
- Division of Neurosurgery, Department of Neuroscience, University of Turin, Turin, Italy
| | - Marco Ajello
- Division of Neurosurgery, Department of Neuroscience, University of Turin, Turin, Italy
| | - Federica Penner
- Division of Neurosurgery, Department of Neuroscience, University of Turin, Turin, Italy
| | - Salvatore Petrone
- Division of Neurosurgery, Department of Neuroscience, University of Turin, Turin, Italy
| | - Alessandro Ducati
- Division of Neurosurgery, Department of Neuroscience, University of Turin, Turin, Italy
| | - Francesco Zenga
- Division of Neurosurgery, Department of Neuroscience, University of Turin, Turin, Italy
| | - Corrado Musso
- Spinal Surgery, Humanitas Research Center, Bergamo, Italy
| | - Diego Garbossa
- Division of Neurosurgery, Department of Neuroscience, University of Turin, Turin, Italy
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Siemionow K, Smith W, Gillespy M, McCormack BM, Gundanna MI, Block JE. Length of stay associated with posterior cervical fusion with intervertebral cages: experience from a device registry. JOURNAL OF SPINE SURGERY 2018; 4:281-286. [PMID: 30069519 DOI: 10.21037/jss.2018.05.27] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Using a multi-center medical device registry, we prospectively collected a set of perioperative and clinical outcomes among patients treated with tissue-sparing, posteriorly-placed intervertebral cage fusion used in the management of symptomatic, degenerative neural compressive disorders of the cervical spine. Methods Cervical fusion utilizing posteriorly-placed intervertebral cages offers a tissue-sparing alternative to traditional instrumentation for the treatment of symptomatic cervical radiculopathy. A registry was established to prospectively collect perioperative and clinical data in a real-world clinical practice setting for patients treated via this approach. This study evaluated length of stay as well as estimated blood loss and procedural time in 271 registry patients. Results The median length of stay was 1.1, 1.1 and 1.2 days for patients having a stand-alone arthrodesis, revision of a pseudoarthrosis, and circumferential fusion (360°), respectively, and was not related to number of levels treated. Historical comparison to published literature demonstrated that average lengths of stay associated with open, posterior lateral mass fixation were consistently ≥4 days. Average blood loss (range, 32-75 mL) and procedural time (range, 51-88 min) were also diminished in patients having tissue-sparing, cervical intervertebral cage fusion compared to open posterior lateral mass fixation. Conclusions Adoption of this tissue-sparing procedure may offer substantial cost-constraining benefits by reducing the length of post-operative hospitalization by, at least, 3 days compared to traditional lateral mass fixation.
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Affiliation(s)
- Kris Siemionow
- Department of Orthopaedic Surgery, University of Illinois, Chicago, IL, USA
| | - William Smith
- Western Regional Center for Brain & Spine Surgery, Las Vegas, NV, USA
| | - Mark Gillespy
- Orthopaedic Clinic of Daytona Beach, Daytona Beach, FL, USA
| | - Bruce M McCormack
- Department of Neurosurgery, University of California, San Francisco, CA, USA
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Lenzi J, Nardone A, Passacantilli E, Caporlingua A, Lapadula G, Caporlingua F. Posterior Cervical Transfacet Fusion with Facetal Spacer for the Treatment of Single-Level Cervical Radiculopathy: A Randomized, Controlled Prospective Study. World Neurosurg 2017; 100:7-14. [PMID: 28065872 DOI: 10.1016/j.wneu.2016.12.125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/24/2016] [Accepted: 12/27/2016] [Indexed: 11/16/2022]
Abstract
BACKGROUND Single-level cervical radiculopathy may be treated conservatively with cervical tractions. Posterior cervical transfacet fusion with a facetal spacer is a viable option. The aim of the present study is to compare posterior cervical transfacet fusion with conservative physical treatment in single-level cervical radiculopathy. METHODS A total of 80 patients were randomized in 2 groups, a surgical group in which patients were given posterior cervical transfacet fusion and a traction group in which patients were treated conservatively with mechanical cervical tractions. Visual analog scale for arm and neck, Neck Disability Index, and Short Form-36 (SF-36) questionnaires were administered preoperatively and after treatment up to 12 months. RESULTS After treatment, visual analog scale arm scores were greater in traction group (4.7 vs. 1.5 the day after treatment) and at follow-up controls (traction group vs. surgical group: 5.3 vs. 0.6 at 1 month, 3.6 vs. 0.3 at 6 months, 1.8 vs. 0.2 at 12 months). Neck Disability Index scores were lower in the surgical group (surgical group vs. traction group: 4.4 vs. 20.3 at 1 month, 1.3 vs. 10.5 at 6 months). SF-36 scores were greater in the surgical group (surgical group vs. traction group: 96 vs. 70 at 1 month, 96.5 vs. 82.6 at 6 months). Neck disability index and SF-36 scores were superimposable between the groups at 12-month follow-up. No adjacent-segment arthrosis or late complications were reported at 1-year follow-up in the surgical group. CONCLUSIONS posterior cervical transfacet fusion is a safe and effective procedure to treat single-level cervical radiculopathy.
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Affiliation(s)
- Jacopo Lenzi
- Neurological Center of Latium, Neurosurgery, Rome, Italy
| | | | | | - Alessandro Caporlingua
- Department of Neurology and Psychiatry, Neurosurgery, "Sapienza" University of Rome, Rome, Italy
| | - Gennaro Lapadula
- Department of Neurology and Psychiatry, Neurosurgery, "Sapienza" University of Rome, Rome, Italy
| | - Federico Caporlingua
- Department of Neurology and Psychiatry, Neurosurgery, "Sapienza" University of Rome, Rome, Italy.
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Voronov LI, Siemionow KB, Havey RM, Carandang G, Patwardhan AG. Biomechanical evaluation of DTRAX(®) posterior cervical cage stabilization with and without lateral mass fixation. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2016; 9:285-90. [PMID: 27601934 PMCID: PMC5003555 DOI: 10.2147/mder.s111031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Introduction Lateral mass screw (LMS) fixation with plates or rods is the current standard procedure for posterior cervical fusion. Recently, implants placed between the facet joints have become available as an alternative to LMS or transfacet screws for patients with cervical spondylotic radiculopathy. The purpose of this study was to evaluate the biomechanical stability of the DTRAX® cervical cage for single- and two-level fusion and compare this to the stability achieved with LMS fixation with rods in a two-level construct. Methods Six cadaveric cervical spine (C3–C7) specimens were tested in flexion–extension, lateral bending, and axial rotation to ±1.5 Nm moment without preload (0 N) in the following conditions: 1) intact (C3–C7), 2) LMS and rods at C4–C5 and C5–C6, 3) removal of all rods (LMS retained) and placement of bilateral posterior cages at C5–C6, 4) bilateral posterior cages at C4–C5 and C5–C6 (without LMS and rods), and 5) C4–C5 and C5–C6 bilateral posterior cages at C4–C5 and C5–C6 with rods reinserted. Results Bilateral posterior cervical cages significantly reduced range of motion in all tested directions in both single- and multilevel constructs (P<0.05). Similar stability was achieved with bilateral posterior cages and LMS in a two-level construct: 0.6°±0.3° vs 1.2°±0.4° in flexion–extension (P=0.001), (5.0°±2.6° vs 3.1°±1.3°) in lateral bending (P=0.053), (1.3°±1.0° vs 2.2°±0.9°) in axial rotation (P=0.091) for posterior cages and LMS, respectively. Posterior cages, when placed as an adjunct to LMS, further reduced range of motion in a multilevel construct (P<0.05). Conclusion Bilateral posterior cages provide similar cervical segmental stability compared with a LMS and rod construct and may be an alternative surgical option for select patients. Furthermore, supplementation of a lateral mass construct with posterior cages increases cervical spine stability in single- and multilevel conditions.
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Affiliation(s)
- Leonard I Voronov
- Department of Orthopaedic Surgery and Rehabilitation, Loyola University Chicago, Maywood; Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines
| | - Krzysztof B Siemionow
- Department of Orthopaedics, University of Illinois College of Medicine at Chicago, Chicago, IL, USA
| | - Robert M Havey
- Department of Orthopaedic Surgery and Rehabilitation, Loyola University Chicago, Maywood; Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines
| | - Gerard Carandang
- Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines
| | - Avinash G Patwardhan
- Department of Orthopaedic Surgery and Rehabilitation, Loyola University Chicago, Maywood; Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines
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Voronov LI, Siemionow KB, Havey RM, Carandang G, Phillips FM, Patwardhan AG. Bilateral posterior cervical cages provide biomechanical stability: assessment of stand-alone and supplemental fixation for anterior cervical discectomy and fusion. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2016; 9:223-30. [PMID: 27471414 PMCID: PMC4948702 DOI: 10.2147/mder.s109588] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Introduction Supplemental posterior instrumentation has been widely used to enhance stability and improve fusion rates in higher risk patients undergoing anterior cervical discectomy and fusion (ACDF). These typically involve posterior lateral mass or pedicle screw fixation with significant inherent risks and morbidities. More recently, cervical cages placed bilaterally between the facet joints (posterior cervical cages) have been used as a less disruptive alternative for posterior fixation. The purpose of this study was to compare the stability achieved by both posterior cages and ACDF at a single motion segment and determine the stability achieved with posterior cervical cages used as an adjunct to single- and multilevel ACDF. Methods Seven cadaveric cervical spine (C2–T1) specimens were tested in the following sequence: intact, C5–C6 bilateral posterior cages, C6–C7 plated ACDF with and without posterior cages, and C3–C5 plated ACDF with and without posterior cages. Range of motion in flexion–extension, lateral bending, and axial rotation was measured for each condition under moment loading up to ±1.5 Nm. Results All fusion constructs significantly reduced the range of motion compared to intact in flexion–extension, lateral bending, and axial rotation (P<0.05). Similar stability was achieved with bilateral posterior cages and plated ACDF at a single level. Posterior cages, when placed as an adjunct to ACDF, further reduced range of motion in both single- and multilevel constructs (P<0.05). Conclusion The biomechanical effectiveness of bilateral posterior cages in limiting cervical segmental motion is comparable to single-level plated ACDF. Furthermore, supplementation of single- and multilevel ACDF with posterior cervical cages provided a significant increase in stability and therefore may be a potential, minimally disruptive option for supplemental fixation for improving ACDF fusion rates.
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Affiliation(s)
- Leonard I Voronov
- Musculoskeletal Biomechanics Laboratory, Department of Research, Edward Hines Jr VA Hospital, Hines, IL, USA; Department of Orthopaedic Surgery and Rehabilitation, Loyola University Chicago, Maywood, IL, USA
| | | | - Robert M Havey
- Musculoskeletal Biomechanics Laboratory, Department of Research, Edward Hines Jr VA Hospital, Hines, IL, USA; Department of Orthopaedic Surgery and Rehabilitation, Loyola University Chicago, Maywood, IL, USA
| | - Gerard Carandang
- Musculoskeletal Biomechanics Laboratory, Department of Research, Edward Hines Jr VA Hospital, Hines, IL, USA; Department of Orthopaedic Surgery and Rehabilitation, Loyola University Chicago, Maywood, IL, USA
| | - Frank M Phillips
- Midwest Orthopedics at Rush, Rush University Medical Center, Chicago, IL, USA
| | - Avinash G Patwardhan
- Musculoskeletal Biomechanics Laboratory, Department of Research, Edward Hines Jr VA Hospital, Hines, IL, USA; Department of Orthopaedic Surgery and Rehabilitation, Loyola University Chicago, Maywood, IL, USA
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Cervical cages placed bilaterally in the facet joints from a posterior approach significantly increase foraminal area. 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 2016; 25:2279-85. [PMID: 26869077 DOI: 10.1007/s00586-016-4430-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 01/09/2016] [Accepted: 01/28/2016] [Indexed: 10/22/2022]
Abstract
PURPOSE Foraminal stenosis is a common cause of cervical radiculopathy. Posterior cervical cages can indirectly increase foraminal area and decompress the nerve root. The aim of this study was to assess the influence of bilateral posterior cervical cages on the surface area and shape of the neural foramen. METHODS Radiographic analysis was performed on 43 subjects enrolled in a prospective, multi-center study. CT scans were obtained at baseline and 6- and 12-months after cervical fusion using bilateral posterior cervical cages. The following measurements were performed on CT scan: foraminal area (A), theoretical area (TA), height (H), superior diagonal (DSI), inferior diagonal (DIS), and inferior diagonal without implant (DISI). Comparisons were performed using R-ANOVA with a significance of α < 0.05. RESULTS Foraminal area, height, TA and DISI were significantly greater following placement of the implant. The mean (SD) A increased from 4.01 (1.09) mm(2) before surgery to 4.24 (1.00) mm(2) at 6 months, and 4.18 (1.05) mm(2) at 12 months after surgery (p < 0.0001). Foraminal height (H) increased from mean (SD) 9.20 (1.08) mm at baseline to 9.65 (1.06) mm and 9.55 (1.14) mm at 6- and 12-months post-operatively, respectively (p < 0.0001). The mean DIS did not change significantly. There was a significant decrease in DSI: 6.18 (1.59) mm pre-operatively, 5.95 (1.47) mm and 5.73 (1.46) mm at 6- and 12-months (p < 0.0001). CONCLUSIONS Implantation of bilateral posterior cervical cages can increase foraminal area and may indirectly decompress the nerve roots. Correlation between increase in foraminal area and clinical outcomes needs further investigation.
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Preliminary Analysis of Adjacent Segment Degeneration in Patients Treated with Posterior Cervical Cages: 2-Year Follow-Up. World Neurosurg 2016; 89:730.e1-7. [PMID: 26836696 DOI: 10.1016/j.wneu.2016.01.053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 01/16/2016] [Accepted: 01/19/2016] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Select patients with unremitting symptoms of cervical radiculopathy may be treated with indirect foraminal decompression and fusion via placement of a cervical cage placed bilaterally through a tissue sparing, posterior approach. Segmental fusion is known to affect adjacent segments. The aim of this study was to assess the affect of posterior fusion using bilateral cervical cages on adjacent segment degeneration (ASDegeneration) at 2 years postoperatively. METHODS Fifty-three patients enrolled in a prospective multicenter study who completed the imaging protocol were available for follow-up at 2 years. Lateral cervical radiographs were acquired preoperatively and at 1- and 2-years postoperatively. Imaging was evaluated for adjacent level degeneration using the following criteria: disk height ratio (DHR) defined as the ratio of the disk height and the lower vertebrae height measured at level above and below; proximal junctional kyphosis (PJK); Kellgren and Lawrence osteoarthritis severity grade (KLOSG); and heterotopic ossification (HO). The results were compared with a repeated analysis of variance test and Bonferroni correction; P < 0.05 was considered significant. RESULTS At 2 years postoperatively, there were no revision surgeries at the operated level or new surgeries at the adjacent levels. Of the 102 segments evaluated, ASDegeneration was identified at 21 levels cranial to and 21 levels caudal to the index level. At 2 years, new mild ASDegeneration signs developed at 3 levels: 1 in the level above and 2 in the level below the operated segment. In patients with pre-existing disk degeneration, mild progression of ASDegeneration signs developed in 6 upper and 2 lower segments. There were no significant changes in DHR and PJK in all patients; however, when patients with signs of ASDegeneration only were evaluated, a significant decrease of the DHR was found. The mean DHRs before surgery and 1 and 2 years after surgery in all patients were 44.0 ± 8.1, 44.0 ± 8.2, and 43.1 ± 8.4 (P = 0.1006) and in ASD patients were 43.8 ± 7.3, 41.9 ± 6.3, and 39.6 ± 8.3 (P = 0.0062), respectively. Overall, at 2 years postoperatively, ASDegeneration was identified in 9 patients (17.6% when compared with all evaluated patients before surgery). CONCLUSIONS In the current study, 5.9% of subjects treated with posterior cervical cages placed bilaterally between the facet joints developed adjacent segment degeneration at 2 years. Mild progression of existing degeneration was observed in 11.8% of subjects. Further evaluation to establish long-term incidence is needed.
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