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Pfender N, Rosner J, Zipser CM, Friedl S, Schubert M, Sutter R, Klarhoefer M, Spirig JM, Betz M, Freund P, Farshad M, Curt A, Hupp M. Increased cranio-caudal spinal cord oscillations are the cardinal pathophysiological change in degenerative cervical myelopathy. Front Neurol 2023; 14:1217526. [PMID: 38020663 PMCID: PMC10663304 DOI: 10.3389/fneur.2023.1217526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Degenerative cervical myelopathy (DCM) is the most common cause of non-traumatic incomplete spinal cord injury, but its pathophysiology is poorly understood. As spinal cord compression observed in standard MRI often fails to explain a patient's status, new diagnostic techniques to assess DCM are one of the research priorities. Minor cardiac-related cranio-caudal oscillations of the cervical spinal cord are observed by phase-contrast MRI (PC-MRI) in healthy controls (HCs), while they become pathologically increased in patients suffering from degenerative cervical myelopathy. Whether transversal oscillations (i.e., anterior-posterior and right-left) also change in DCM patients is not known. Methods We assessed spinal cord motion simultaneously in all three spatial directions (i.e., cranio-caudal, anterior-posterior, and right-left) using sagittal PC-MRI and compared physiological oscillations in 18 HCs to pathological changes in 72 DCM patients with spinal canal stenosis. The parameter of interest was the amplitude of the velocity signal (i.e., maximum positive to maximum negative peak) during the cardiac cycle. Results Most patients suffered from mild DCM (mJOA score 16 (14-18) points), and the majority (68.1%) presented with multisegmental stenosis. The spinal canal was considerably constricted in DCM patients in all segments compared to HCs. Under physiological conditions in HCs, the cervical spinal cord oscillates in the cranio-caudal and anterior-posterior directions, while right-left motion was marginal [e.g., segment C5 amplitudes: cranio-caudal: 0.40 (0.27-0.48) cm/s; anterior-posterior: 0.18 (0.16-0.29) cm/s; right-left: 0.10 (0.08-0.13) cm/s]. Compared to HCs, DCM patients presented with considerably increased cranio-caudal oscillations due to the cardinal pathophysiologic change in non-stenotic [e.g., segment C5 amplitudes: 0.79 (0.49-1.32) cm/s] and stenotic segments [.g., segment C5 amplitudes: 0.99 (0.69-1.42) cm/s]). In contrast, right-left [e.g., segment C5 amplitudes: non-stenotic segment: 0.20 (0.13-0.32) cm/s; stenotic segment: 0.11 (0.09-0.18) cm/s] and anterior-posterior oscillations [e.g., segment C5 amplitudes: non-stenotic segment: 0.26 (0.15-0.45) cm/s; stenotic segment: 0.11 (0.09-0.18) cm/s] remained on low magnitudes comparable to HCs. Conclusion Increased cranio-caudal oscillations of the cervical cord are the cardinal pathophysiologic change and can be quantified using PC-MRI in DCM patients. This study addresses spinal cord oscillations as a relevant biomarker reflecting dynamic mechanical cord stress in DCM patients, potentially contributing to a loss of function.
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Affiliation(s)
- Nikolai Pfender
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, Bern, Switzerland
| | - Carl M. Zipser
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Susanne Friedl
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Schubert
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Reto Sutter
- Radiology, Balgrist University Hospital, Zurich, Switzerland
| | | | - José M. Spirig
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Michael Betz
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Patrick Freund
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Mazda Farshad
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Markus Hupp
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
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Meisterhans M, Hagel V, Spirig JM, Fasser MR, Farshad M, Widmer J. The Biomechanics of the Transpedicular Endoscopic Approach. Spine (Phila Pa 1976) 2023:00007632-990000000-00504. [PMID: 37942817 DOI: 10.1097/brs.0000000000004871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 10/31/2023] [Indexed: 11/10/2023]
Abstract
STUDY DESIGN Biomechanical cadaveric study. OBJECTIVE The goal of this study was to analyze the effects of an endoscopic transpedicular approach with different drill diameters (6 and 8 mm) to compare them with the intact native side. In addition, the influence of bone quality on the resistance of the pedicle was investigated. SUMMARY OF BACKGROUND DATA Clinical studies have repeatedly highlighted the benefits of endoscopic transpedicular decompression for down-migrated lumbar disc herniations. However, the biomechanical effects on pedicle stability have not been studied up to now. METHODS Twenty-four vertebras originating from four fresh-frozen cadavers were tested under uniaxial compression load in a ramp-to-failure test: (1) the tunneled pedicle on one side, and (2) the native pedicle on the other side. Twelve lumbar vertebrae were assigned to a drill diameter of 6 mm and the other 12 to a diameter of 8 mm. RESULTS The median ratio of sustained force for the operated side compared to the intact contralateral side is equal to 74% (63-88) for both drill diameters combined. An 8 mm transpedicular approach recorded an axial resistance of 77% (60-88) compared to the intact contralateral side ( P =0.002). A 6 mm approach resulted in an axial resistance of 72% (66-84) compared to the intact opposite side ( P =0.01). No significant difference between the two different drill diameters was recorded ( P =1). For all 3 subgroups (intact, 8 mm, 6 mm) the HU-values and the absolute resistance force showed significant correlations (intact: ρ=0.859; P <0.001; 8 mm: ρ=0.902; P <0.001; 6 mm: ρ=0.835; P <0.001). CONCLUSION Transpedicular approach significantly reduces the axial resistance force of the pedicle, which may lead to pedicle fracture. Bone quality correlated positively with the absolute resistance force of the pedicle, whereas the influence of the drill hole diameter plays only a limited role.
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Affiliation(s)
- Michel Meisterhans
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Vincent Hagel
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Spine Center, Asklepios Klinik Lindau, Lindau, Germany
| | - José M Spirig
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Institute of Biomechanics, Balgrist Campus, ETH Zurich, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jonas Widmer
- Institute of Biomechanics, Balgrist Campus, ETH Zurich, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Dudli S, Heggli I, Laux CJ, Spirig JM, Wanivenhaus F, Betz M, Germann C, Farshad-Amacker NA, Herger N, Mengis T, Brunner F, Farshad M, Distler O. Role of C-reactive protein in the bone marrow of Modic type 1 changes. J Orthop Res 2023; 41:1115-1122. [PMID: 36062874 PMCID: PMC9985669 DOI: 10.1002/jor.25437] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/19/2022] [Accepted: 08/29/2022] [Indexed: 02/04/2023]
Abstract
Modic type 1 changes (MC1) are vertebral bone marrow lesions and associate with low back pain. Increased serum C-reactive protein (CRP) has inconsistently been associated with MC1. We aimed to provide evidence for the role of CRP in the tissue pathophysiology of MC1 bone marrow. From 13 MC1 patients undergoing spinal fusion at MC1 levels, vertebral bone marrow aspirates from MC1 and intrapatient control bone marrow were taken. Bone marrow CRP, interleukin (IL)-1, and IL-6 were measured with enzyme-linked immunosorbent assays; lactate dehydrogenase (LDH) was measured with a colorimetric assay. CRP, IL-1, and IL-6 were compared between MC1 and control bone marrow. Bone marrow CRP was correlated with blood CRP and with bone marrow IL-1, IL-6, and LDH. CRP expression by marrow cells was measured with a polymerase chain reaction. Increased CRP in MC1 bone marrow (mean difference: +0.22 mg CRP/g, 95% confidence interval [CI] [-0.04, 0.47], p = 0.088) correlated with blood CRP (r = 0.69, p = 0.018), with bone marrow IL-1β (ρ = 0.52, p = 0.029) and IL-6 (ρ = 0.51, p = 0.031). Marrow cells did not express CRP. Increased LDH in MC1 bone marrow (143.1%, 95% CI [110.7%, 175.4%], p = 0.014) indicated necrosis. A blood CRP threshold of 3.2 mg/L detected with 100% accuracy increased CRP in MC1 bone marrow. In conclusion, the association of CRP with inflammatory and necrotic changes in MC1 bone marrow provides evidence for a pathophysiological role of CRP in MC1 bone marrow.
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Affiliation(s)
- Stefan Dudli
- Department of Rheumatology, Center of Experimental Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland
- Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Irina Heggli
- Department of Rheumatology, Center of Experimental Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Christoph J. Laux
- Department of Orthopeadics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - José M. Spirig
- Department of Orthopeadics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Florian Wanivenhaus
- Department of Orthopeadics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Michael Betz
- Department of Orthopeadics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Christoph Germann
- Department of Radiology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Nadja A. Farshad-Amacker
- Department of Radiology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Nick Herger
- Department of Rheumatology, Center of Experimental Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Tamara Mengis
- Department of Rheumatology, Center of Experimental Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Florian Brunner
- Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopeadics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Oliver Distler
- Department of Rheumatology, Center of Experimental Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Burkhard MD, Spirig JM, Wanivenhaus F, Cornaz F, Fasser MR, Widmer J, Farshad M. Residual motion of different posterior instrumentation and interbody fusion constructs. Eur Spine J 2023; 32:1411-1420. [PMID: 36820922 DOI: 10.1007/s00586-023-07597-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/24/2023]
Abstract
PURPOSE To elucidate residual motion of cortical screw (CS) and pedicle screw (PS) constructs with unilateral posterior lumbar interbody fusion (ul-PLIF), bilateral PLIF (bl-PLIF), facet-sparing transforaminal lumbar interbody fusion (fs-TLIF), and facet-resecting TLIF (fr-TLIF). METHODS A total of 35 human cadaver lumbar segments were instrumented with PS (n = 18) and CS (n = 17). Range of motion (ROM) and relative ROM changes were recorded in flexion/extension (FE), lateral bending (LB), axial rotation (AR), lateral shear (LS), anterior shear (AS), and axial compression (AC) in five instrumentational states: without interbody fusion (wo-IF), ul-PLIF, bl-PLIF, fs-TLIF, and fr-TLIF. RESULTS Whereas FE, LB, AR, and AC noticeably differed between the instrumentational states, AS and LS were less prominently affected. Compared to wo-IF, ul-PLIF caused a significant increase in ROM with PS (FE + 42%, LB + 24%, AR + 34%, and AC + 77%), however, such changes were non-significant with CS. ROM was similar between wo-IF and all other interbody fusion techniques. Insertion of a second PLIF (bl-PLIF) significantly decreased ROM with CS (FE -17%, LB -26%, AR -20%, AC -51%) and PS (FE - 23%, LB - 14%, AR - 20%, AC - 45%,). Facet removal in TLIF significantly increased ROM with CS (FE + 6%, LB + 9%, AR + 17%, AC of + 23%) and PS (FE + 7%, AR + 12%, AC + 13%). CONCLUSION bl-PLIF and TLIF show similarly low residual motion in both PS and CS constructs, but ul-PLIF results in increased motion. The fs-TLIF technique is able to further decrease motion compared to fr-TLIF in both the CS and PS constructs.
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Affiliation(s)
- Marco D Burkhard
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
| | - José M Spirig
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Florian Wanivenhaus
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Frédéric Cornaz
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Institute for Biomechanics, Balgrist Campus, ETH Zurich, Lengghalde 5, CH-8008, Zurich, Switzerland.,Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jonas Widmer
- Institute for Biomechanics, Balgrist Campus, ETH Zurich, Lengghalde 5, CH-8008, Zurich, Switzerland.,Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
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Farshad M, Hagel V, Spirig JM, Fasser MR, Widmer J, Burkhard MD, Calek AK. Biomechanics of Transforaminal Endoscopic Approaches. Spine (Phila Pa 1976) 2022; 47:1753-1760. [PMID: 36083835 PMCID: PMC10010693 DOI: 10.1097/brs.0000000000004471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/20/2022] [Accepted: 08/16/2022] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Biomechanical cadaveric study. OBJECTIVE The aim of this study was to compare the effect of transforaminal endoscopic approaches with open decompression procedures. SUMMARY OF BACKGROUND DATA Clinical studies have repeatedly highlighted the benefits of endoscopic decompression, however, the biomechanical effects of endoscopic approaches (with and without injury to the disk) have not been studied up to now. MATERIALS AND METHODS Twelve spinal segments originating from four fresh-frozen cadavers were biomechanically tested in a load-controlled endoscopic transforaminal approach study. Segmental range of motion (ROM) after endoscopic approach was compared with segmental ROM after (1) microsurgical decompression with unilateral laminotomy and (2) midline decompression with bilateral laminotomy. In the intact state and after decompression, the segments were loaded in flexion-extension (FE), lateral shear (LS), lateral bending (LB), anterior shear (AS), and axial rotation (AR). RESULTS Vertebral segment ROM was comparable between the two endoscopic transforaminal approaches. However, there was a-statistically nonsignificant-trend for a larger ROM after accessing via the inside-out technique: FE: +3% versus +7%, P =0.484; LS: +1% versus +12%, P =0.18; LB: +0.6% versus +9%, P =0.18; AS: +2% versus +11%, P =0.31; AR: -4% versus +5%, P =0.18. No significant difference in vertebral segment ROM was seen between the transforaminal endoscopic approaches and open unilateral decompression. Vertebral segment ROM was significantly smaller with the transforaminal endoscopic approaches compared with midline decompression for almost all loading scenarios: FE: +4% versus +17%, P =0.005; AS: +6% versus 21%, P =0.007; AR: 0% versus +24%, P =0.002. CONCLUSION The transforaminal endoscopic intracanal technique preserves the native ROM of lumbar vertebral segments and shows a trend toward relative biomechanical superiority over the inside-out technique and open decompression procedures.
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Affiliation(s)
- Mazda Farshad
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Vincent Hagel
- Spine Center, Asklepios Klinik Lindau, Lindau, Germany
| | - José M. Spirig
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Institute of Biomechanics, Balgrist Campus, ETH Zurich, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jonas Widmer
- Institute of Biomechanics, Balgrist Campus, ETH Zurich, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marco D. Burkhard
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Anna-Katharina Calek
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Carrillo F, Esfandiari H, Müller S, von Atzigen M, Massalimova A, Suter D, Laux CJ, Spirig JM, Farshad M, Fürnstahl P. Surgical Process Modeling for Open Spinal Surgeries. Front Surg 2022; 8:776945. [PMID: 35145990 PMCID: PMC8821818 DOI: 10.3389/fsurg.2021.776945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/30/2021] [Indexed: 11/13/2022] Open
Abstract
Modern operating rooms are becoming increasingly advanced thanks to the emerging medical technologies and cutting-edge surgical techniques. Current surgeries are transitioning into complex processes that involve information and actions from multiple resources. When designing context-aware medical technologies for a given intervention, it is of utmost importance to have a deep understanding of the underlying surgical process. This is essential to develop technologies that can correctly address the clinical needs and can adapt to the existing workflow. Surgical Process Modeling (SPM) is a relatively recent discipline that focuses on achieving a profound understanding of the surgical workflow and providing a model that explains the elements of a given surgery as well as their sequence and hierarchy, both in quantitative and qualitative manner. To date, a significant body of work has been dedicated to the development of comprehensive SPMs for minimally invasive baroscopic and endoscopic surgeries, while such models are missing for open spinal surgeries. In this paper, we provide SPMs common open spinal interventions in orthopedics. Direct video observations of surgeries conducted in our institution were used to derive temporal and transitional information about the surgical activities. This information was later used to develop detailed SPMs that modeled different primary surgical steps and highlighted the frequency of transitions between the surgical activities made within each step. Given the recent emersion of advanced techniques that are tailored to open spinal surgeries (e.g., artificial intelligence methods for intraoperative guidance and navigation), we believe that the SPMs provided in this study can serve as the basis for further advancement of next-generation algorithms dedicated to open spinal interventions that require a profound understanding of the surgical workflow (e.g., automatic surgical activity recognition and surgical skill evaluation). Furthermore, the models provided in this study can potentially benefit the clinical community through standardization of the surgery, which is essential for surgical training.
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Affiliation(s)
- Fabio Carrillo
- Research in Orthopedic Computer Science, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Hooman Esfandiari
- Research in Orthopedic Computer Science, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- *Correspondence: Hooman Esfandiari ;
| | - Sandro Müller
- Research in Orthopedic Computer Science, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marco von Atzigen
- Research in Orthopedic Computer Science, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Laboratory for Orthopaedic Biomechanics, Institute for Biomechanics, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Aidana Massalimova
- Research in Orthopedic Computer Science, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Daniel Suter
- Research in Orthopedic Computer Science, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Christoph J. Laux
- Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - José M. Spirig
- Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Philipp Fürnstahl
- Research in Orthopedic Computer Science, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Altorfer FCS, Sutter R, Farshad M, Spirig JM, Farshad-Amacker NA. MRI appearance of adjunct surgical material used in spine surgery. Spine J 2022; 22:75-83. [PMID: 34284130 DOI: 10.1016/j.spinee.2021.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/04/2021] [Accepted: 07/08/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Early postoperative MR images are frequently necessary after spine surgery. The appearance of commonly used adjunct hemostatic agents and dural sealants in MR images has not been systematically evaluated. PURPOSE The purpose of this experimental study was to systematically analyze and describe the characteristics of the most commonly applied hemostatic agents and dural sealants in spine surgery on early postoperative MR images. STUDY DESIGN Cadaver Study METHODS: Four commonly applied dural sealants (Duraseal, Bioglue, Tachosil, Tisseel) and five commonly used hemostatic agents (Surgiflo, Bonewax, , Spongostan, Gelfoam, Avitene) were investigated. The experimental setting involved a human cadaver where a standard left-sided laminotomy was performed on nine levels of the thoracolumbar spine, and the materials were separately applied and mixed with fresh blood or water for hemostatic and dural sealants, respectively. The cadaver model was scanned at a 3 Tesla MRI and the imaging findings for all materials were compared to the surrounding tissue and systematically reported. RESULTS All investigated dural sealants and hemostatic agents were distinguishable from the surrounding tissue on MR images with different appearances on the MR sequences. A detailed atlas for the identification of the materials in postoperative spine MRI was established. CONCLUSION Commonly used hemostatic agents and dural sealants can be successfully identified on early postoperative spine MRI. CLINICAL SIGNIFICANCE Knowledge about MRI appearances of commonly used adjunct surgical materials helps in interpretation of postoperative imaging and supports clinical decision making.
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Affiliation(s)
- Franziska C S Altorfer
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Switzerland.
| | - Reto Sutter
- Department of Radiology, Balgrist University Hospital, University of Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Switzerland
| | - José M Spirig
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Switzerland
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Farshad M, Burkhard MD, Spirig JM. Occipitopexy as a Fusionless Solution for Dropped Head Syndrome: A Case Report. JBJS Case Connect 2021; 11:01709767-202109000-00080. [PMID: 34398850 DOI: 10.2106/jbjs.cc.21.00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CASE A 68-year-old woman suffered from an irradiation-induced dropped head syndrome (DHS). Fusion surgery was vehemently rejected by the patient. A new surgical method, avoiding fusion, was invented and performed to treat her DHS. This novel surgical technique of "occipitopexy"-a ligamentous fixation of the occiput to the upper thoracic spine-is described in detail. One year postoperatively, the patient was very satisfied, able to maintain a horizontal gaze, and rotate her head 20° to each side. CONCLUSION This is the first report describing "occipitopexy" as an alternative to cervicothoracic fusion for patients with flexible DHS.
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Affiliation(s)
- Mazda Farshad
- Department of Orthopaedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Heggli I, Epprecht S, Juengel A, Schuepbach R, Farshad-Amacker N, German C, Mengis T, Herger N, Straumann L, Baumgartner S, Betz M, Spirig JM, Wanivenhaus F, Ulrich N, Bellut D, Brunner F, Farshad M, Distler O, Dudli S. Pro-fibrotic phenotype of bone marrow stromal cells in Modic type 1 changes. Eur Cell Mater 2021; 41:648-667. [PMID: 34101158 DOI: 10.22203/ecm.v041a42] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Modic type 1 changes (MC1) are painful vertebral bone marrow lesions frequently found in patients suffering from chronic low-back pain. Marrow fibrosis is a hallmark of MC1. Bone marrow stromal cells (BMSCs) are key players in other fibrotic bone marrow pathologies, yet their role in MC1 is unknown. The present study aimed to characterise MC1 BMSCs and hypothesised a pro-fibrotic role of BMSCs in MC1. BMSCs were isolated from patients undergoing lumbar spinal fusion from MC1 and adjacent control vertebrae. Frequency of colony-forming unit fibroblast (CFU-F), expression of stem cell surface markers, differentiation capacity, transcriptome, matrix adhesion, cell contractility as well as expression of pro-collagen type I alpha 1, α-smooth muscle actin, integrins and focal adhesion kinase (FAK) were compared. More CFU-F and increased expression of C-X-C-motif-chemokine 12 were found in MC1 BMSCs, possibly indicating overrepresentation of a perisinusoidal BMSC population. RNA sequencing analysis showed enrichment in extracellular matrix proteins and fibrosis-related signalling genes. Increases in pro-collagen type I alpha 1 expression, cell adhesion, cell contractility and phosphorylation of FAK provided further evidence for their pro-fibrotic phenotype. Moreover, a leptin receptor high expressing (LEPRhigh) BMSC population was identified that differentiated under transforming growth factor beta 1 stimulation into myofibroblasts in MC1 but not in control BMSCs. In conclusion, pro-fibrotic changes in MC1 BMSCs and a LEPRhigh MC1 BMSC subpopulation susceptible to myofibroblast differentiation were found. Fibrosis is a hallmark of MC1 and a potential therapeutic target. A causal link between the pro-fibrotic phenotype and clinical characteristics needs to be demonstrated.
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Affiliation(s)
- I Heggli
- Centre of Experimental Rheumatology, Balgrist Campus AG, Lengghalde 5, 8008 Zurich,
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10
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Spirig JM, Winkler E, Cornaz F, Fasser MR, Betz M, Snedeker JG, Widmer J, Farshad M. Biomechanical performance of bicortical versus pericortical bone trajectory (CBT) pedicle screws. Eur Spine J 2021; 30:2292-2300. [PMID: 34057540 DOI: 10.1007/s00586-021-06878-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 04/18/2021] [Accepted: 05/13/2021] [Indexed: 01/12/2023]
Abstract
PURPOSE The cortical bone trajectory (CBT) is an alternative to the traditional pedicle screw trajectory (TT) in posterior spinal instrumentation, enhancing screw contact with cortical bone and therefore increasing fixation strength. Additional to the trajectory, insertion depth (pericortical vs. bicortical placement) could be a relevant factor affecting the fixation strength. However, the potential biomechanical benefit of a bicortical placement of CBT screws is unknown. Therefore, the aim of this study was to quantify the fixation strength of pericortical- versus bicortical-CBT (pCBT versus bCBT) screws in a randomized cadaveric study. METHODS Pedicle screws were either placed pericortical or bicortical with a CBT in 20 lumbar vertebrae (2 × 20 instrumented pedicles) from four human spine cadavers by using patient-specific templates. Instrumented specimens underwent physiological cyclic loading testing (1'800'000 cycles, 10 Hz), including shear and tension loads as well as bending moments. Translational and angular displacements of the screws were quantified and compared between the two techniques. RESULTS There was a slight decrease in translational (0.2 mm ± 0.09 vs. 0.24 mm ± 0.11) and angular displacements (0.06° ± 0.05 vs. 0.13° ± 0.11) of bCBT screws when compared with pCBT screws after 1'800'000 cycles. However, the results were non-significant (p > 0.05). CONCLUSION The authors do not recommend placing CBT screws bicortically, as no relevant biomechanical advantage is gained while the potential risk for iatrogenic injury to structures anterior to the spine is increased.
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Affiliation(s)
- José M Spirig
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
| | - Elin Winkler
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Frédéric Cornaz
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Marie-Rosa Fasser
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.,Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | - Michael Betz
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Jess G Snedeker
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.,Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | - Jonas Widmer
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.,Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | - Mazda Farshad
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
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11
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Hupp M, Pfender N, Vallotton K, Rosner J, Friedl S, Zipser CM, Sutter R, Klarhöfer M, Spirig JM, Betz M, Schubert M, Freund P, Farshad M, Curt A. The Restless Spinal Cord in Degenerative Cervical Myelopathy. AJNR Am J Neuroradiol 2021; 42:597-609. [PMID: 33541903 DOI: 10.3174/ajnr.a6958] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 10/12/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The spinal cord is subject to a periodic, cardiac-related movement, which is increased at the level of a cervical stenosis. Increased oscillations may exert mechanical stress on spinal cord tissue causing intramedullary damage. Motion analysis thus holds promise as a biomarker related to disease progression in degenerative cervical myelopathy. Our aim was characterization of the cervical spinal cord motion in patients with degenerative cervical myelopathy. MATERIALS AND METHODS Phase-contrast MR imaging data were analyzed in 55 patients (37 men; mean age, 56.2 [SD,12.0] years; 36 multisegmental stenoses) and 18 controls (9 men, P = .368; mean age, 62.2 [SD, 6.5] years; P = .024). Parameters of interest included the displacement and motion pattern. Motion data were pooled on the segmental level for comparison between groups. RESULTS In patients, mean craniocaudal oscillations were increased manifold at any level of a cervical stenosis (eg, C5 displacement: controls [n = 18], 0.54 [SD, 0.16] mm; patients [n = 29], monosegmental stenosis [n = 10], 1.86 [SD, 0.92] mm; P < .001) and even in segments remote from the level of the stenosis (eg, C2 displacement: controls [n = 18], 0.36 [SD, 0.09] mm; patients [n = 52]; stenosis: C3, n = 21; C4, n = 11; C5, n = 18; C6, n = 2; 0.85 [SD, 0.46] mm; P < .001). Motion at C2 differed with the distance to the next stenotic segment and the number of stenotic segments. The motion pattern in most patients showed continuous spinal cord motion throughout the cardiac cycle. CONCLUSIONS Patients with degenerative cervical myelopathy show altered spinal cord motion with increased and ongoing oscillations at and also beyond the focal level of stenosis. Phase-contrast MR imaging has promise as a biomarker to reveal mechanical stress to the cord and may be applicable to predict disease progression and the impact of surgical interventions.
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Affiliation(s)
- M Hupp
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.)
| | - N Pfender
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.)
| | - K Vallotton
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.)
| | - J Rosner
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.).,Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
| | - S Friedl
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.)
| | - C M Zipser
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.)
| | | | - M Klarhöfer
- Siemens Healthcare AG (M.K.), Zurich, Switzerland
| | - J M Spirig
- University Spine Center Zurich (J.M.S., M.B., M.F., A.C.), Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - M Betz
- University Spine Center Zurich (J.M.S., M.B., M.F., A.C.), Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - M Schubert
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.)
| | - P Freund
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.)
| | - M Farshad
- University Spine Center Zurich (J.M.S., M.B., M.F., A.C.), Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - A Curt
- From the Spinal Cord Injury Center (M.H., N.P., K.V., J.R., S.F., C.M.Z., M.S., P.F., A.C.).,University Spine Center Zurich (J.M.S., M.B., M.F., A.C.), Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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12
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Müller F, Roner S, Liebmann F, Spirig JM, Fürnstahl P, Farshad M. Augmented reality navigation for spinal pedicle screw instrumentation using intraoperative 3D imaging. Spine J 2020; 20:621-628. [PMID: 31669611 DOI: 10.1016/j.spinee.2019.10.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 10/19/2019] [Accepted: 10/21/2019] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Due to recent developments in augmented reality with head-mounted devices, holograms of a surgical plan can be displayed directly in the surgeon's field of view. To the best of our knowledge, three dimensional (3D) intraoperative fluoroscopy has not been explored for the use with holographic navigation by head-mounted devices in spine surgery. PURPOSE To evaluate the surgical accuracy of holographic pedicle screw navigation by head-mounted device using 3D intraoperative fluoroscopy. STUDY DESIGN In this experimental cadaver study, the accuracy of surgical navigation using a head-mounted device was compared with navigation with a state-of-the-art pose-tracking system. METHODS Three lumbar cadaver spines were embedded in nontransparent agar gel, leaving only commonly visible anatomy in sight. Intraoperative registration of preoperative planning was achieved by 3D fluoroscopy and fiducial markers attached to lumbar vertebrae. Trackable custom-made drill sleeve guides enabled real-time navigation. In total, 20 K-wires were navigated into lumbar pedicles using AR-navigation, 10 K-wires by the state-of-the-art pose-tracking system. 3D models obtained from postexperimental CT scans were used to measure surgical accuracy. MF is the founder and shareholder of Incremed AG, a Balgrist University Hospital start-up focusing on the development of innovative techniques for surgical executions. The other authors declare no conflict of interest concerning the contents of this study. No external funding was received for this study. RESULTS No significant difference in accuracy was measured between AR-navigated drillings and the gold standard with pose-tracking system with mean translational errors between entry points (3D vector distance; p=.85) of 3.4±1.6 mm compared with 3.2±2.0 mm, and mean angular errors between trajectories (3D angle; p=.30) of 4.3°±2.3° compared with 3.5°±1.4°. CONCLUSIONS In conclusion, holographic navigation by use of a head-mounted device achieve accuracy comparable to the gold standard of high-end pose-tracking systems. CLINICAL SIGNIFICANCE These promising results could result in a new way of surgical navigation with minimal infrastructural requirements but now have to be confirmed in clinical studies.
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Affiliation(s)
- Fabio Müller
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008 Zurich, Switzerland.
| | - Simon Roner
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008 Zurich, Switzerland
| | - Florentin Liebmann
- Computer Assisted Research and Development Group, Balgrist University Hospital, University of Zurich, Lengghalde 5, 8008 Zurich, Switzerland; Laboratory for Orthopedic Biomechanics, ETH Zurich, Forchstrasse 328, 8008 Zurich, Switzerland
| | - José M Spirig
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008 Zurich, Switzerland
| | - Philipp Fürnstahl
- Computer Assisted Research and Development Group, Balgrist University Hospital, University of Zurich, Lengghalde 5, 8008 Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008 Zurich, Switzerland
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Farshad-Amacker NA, Bay T, Rosskopf AB, Spirig JM, Wanivenhaus F, Pfirrmann CWA, Farshad M. Ultrasound-guided interventions with augmented reality in situ visualisation: a proof-of-mechanism phantom study. Eur Radiol Exp 2020; 4:7. [PMID: 32020366 PMCID: PMC7000569 DOI: 10.1186/s41747-019-0129-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/29/2019] [Indexed: 02/07/2023] Open
Abstract
Background Ultrasound (US) images are currently displayed on monitors, and their understanding needs good orientation skills. Direct overlay of US images onto the according anatomy is possible with augmented reality (AR) technologies. Our purpose was to explore the performance of US-guided needle placement with and without AR in situ US viewing. Methods Three untrained operators and two experienced radiologists performed 200 US-guided punctures: 100 with and 100 without AR in situ US. The punctures were performed in two different phantoms, a leg phantom with soft tissue lesions and a vessel phantom. Time to puncture and number of needle passes were recorded for each puncture. Data are reported as median [range] according to their non-normal distribution. Results AR in situ US resulted in reduced time (median [range], 13 s [3–101] versus 14 s [3–220]) and number of needle passes (median [range], 1 [1–4] versus 1 [1–8]) compared to the conventional technique. The initial gap in performance of untrained versus experienced operators with the conventional US (time, 21.5 s [3–220] versus 10.5 s [3–94] and needle passes 1 [1–8] versus 1 [1, 2]) was reduced to 12.5 s [3–101] versus 13 s [3–100] and 1 [1–4] versus 1 [1–4] when using AR in situ US, respectively. Conclusion AR in situ US could be a potential breakthrough in US applications by simplifying operator’s spatial orientation and reducing experience-based differences in performance of US-guided interventions. Further studies are needed to confirm these preliminary phantom results.
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Affiliation(s)
| | - Till Bay
- Incremed AG, Lenghalde 5, 8008, Zurich, Switzerland
| | - Andrea B Rosskopf
- Radiology, Balgrist University Hospital, Forchstrasse, 340, 8008, Zurich, Switzerland
| | - José M Spirig
- Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Florian Wanivenhaus
- Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | | | - Mazda Farshad
- Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
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Wanivenhaus F, Neuhaus C, Liebmann F, Roner S, Spirig JM, Farshad M. Augmented reality-assisted rod bending in spinal surgery. Spine J 2019; 19:1687-1689. [PMID: 31563336 DOI: 10.1016/j.spinee.2019.06.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 02/03/2023]
Affiliation(s)
- Florian Wanivenhaus
- Department of Orthopaedics, University of Zurich, Balgrist University Hospital, Forchstrasse 340, 8008 Zürich, Switzerland.
| | - Caroline Neuhaus
- Department of Orthopaedics, University of Zurich, Balgrist University Hospital, Forchstrasse 340, 8008 Zürich, Switzerland
| | - Florentin Liebmann
- Computer Assisted Research& Development, Balgrist CAMPUS, Lengghalde 5, 8008 Zürich, Switzerland
| | - Simon Roner
- Department of Orthopaedics, University of Zurich, Balgrist University Hospital, Forchstrasse 340, 8008 Zürich, Switzerland
| | - José M Spirig
- Department of Orthopaedics, University of Zurich, Balgrist University Hospital, Forchstrasse 340, 8008 Zürich, Switzerland
| | - Mazda Farshad
- Department of Orthopaedics, University of Zurich, Balgrist University Hospital, Forchstrasse 340, 8008 Zürich, Switzerland
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Spirig JM, Frank MN, Regli L, Stieglitz LH. Shunt age-related complications in adult patients with suspected shunt dysfunction. A recommended diagnostic workup. Acta Neurochir (Wien) 2017; 159:1421-1428. [PMID: 28616668 DOI: 10.1007/s00701-017-3237-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 05/31/2017] [Indexed: 12/01/2022]
Abstract
BACKGROUND Patients admitted for suspicion of shunt dysfunction (SD) often show unspecific symptoms and require time-consuming, expensive and even invasive diagnostics involving significant radiation exposure. The purpose of this retrospective study was to analyse the current diagnostic procedures and to propose a process optimisation. METHOD As all patients admitted for suspicion of SD receive imaging studies, we searched for adult patients receiving neuroimaging in the period from January 2010 to July 2013, analysing referring diagnosis, clinical signs, products, diagnostic process and final diagnosis. Recursive partitioning was used to define time intervals for differentiating types of SD. RESULTS A total of 148 patients, aged 18-89 (mean, 54) years, were studied. Forty-two percent were referred by a hospital or rehabilitation centre, 30% by general practitioners and 24% were self-referrals. The admission diagnosis was in the majority "shunt dysfunction" only. Further differentiations were rarely made. An SD was confirmed in 46% of the patients. In 17%, the symptoms were based on another cause and in 37% they could not be clearly attributed to any specific disorder. Abdominal dislocations (2%) and shunt infections (5%) were found within the first 6 months. Over- (3%) and under-drainage (14%) were the most frequent complications during the first 4 years. Disconnections (13%) occurred generally 4 years or more after implantation. Only shunt obstruction (9%) showed no temporal pattern. CONCLUSIONS Symptoms of SD remain mostly unspecific. This study showed that the type of SD depends on the time interval from implantation. We propose a workup strategy for patients with SD based on the temporal profile.
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Affiliation(s)
- José M Spirig
- Department of Neurosurgery, University of Zurich and University Hospital Zurich, 8091, Zurich, Switzerland
| | - Melanie N Frank
- Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Luca Regli
- Department of Neurosurgery, University of Zurich and University Hospital Zurich, 8091, Zurich, Switzerland
| | - Lennart H Stieglitz
- Department of Neurosurgery, University of Zurich and University Hospital Zurich, 8091, Zurich, Switzerland.
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