Article Figures & Data
Figures
- Figure 1
Intraoperative photo demonstrating proximal junctional tether technique as described by Iyer et al.30 Image shows dual surgical nylon tape augmentation extending from a hole through the base of the spinous process at the upper-most instrumented vertebra (UIV) and tied to the rods and from a hole through the base of the spinous process at the UIV+1 and tied to the rods. Source: Iyer et al. Global Spine J. 2020;10[6]:692–699. Copyright 2019. Reprinted with permission of SAGE Publications.
- Figure 2
Demonstration of proximal junctional tether technique as described by Rabinovich et al34 and Buell et al.42 A high-speed drill is used to create holes through the base of the spinous processes at the upper-most instrumented vertebra (UIV) and UIV+2 (A). The tether is passed through the interspinous ligament between the UIV and UIV-1, then through the spinous processes of UIV+1 (B), UIV+2, back through UIV+1, and then back through the interspinous ligament between the UIV and UIV-1. The tether is then tensioned and attached to the rods with a connector using the tower tensioning system (C). The general weave technique and a final intraoperative photo are shown in panel D.
- Figure 3
Intraoperative photos demonstrating proximal junctional tether technique as described by Rodnoi et al.35 (A) Polyethylene tape is passed through the base of the spinous process of the upper-most instrumented vertebra (UIV)+1. (B) The tape is tied around a crosslink, and excess tether is trimmed. (C) Compression between the crosslink and subjacent pedicle screw is performed to tension the tether. (D) The crosslink is final-tightened. Source: Rodnoi et al. Neurospine. 2021;18[3]:580–586. Copyright 2021. Reprinted with permission.
- Figure 4
Illustrations demonstrating proximal junctional tether technique as described by Safaee et al.37 A matchstick burr is used to create holes through the spinous processes of the upper-most instrumented vertebra (UIV), UIV+1, and UIV-1. A sublaminar cable is passed through each level (A) and then pulled to the side (B). The same process is repeated using a second cable on the opposite side (C). The cables are pulled distally to create desired tension (D). The cables are secured to the rods on each side using connectors. Source: Copyright Kenneth X. Probst. Reprinted with permission of XavierStudio.
- Figure 5
Illustrations and intraoperative photos demonstrating the sublaminar tether technique as described by Yagi et al.40 Ligamentum flavum proximal and distal to the upper-most instrumented vertebra (UIV)+1 is partially removed using a high-speed burr (A). Two sublaminar bands are passed under the UIV+1 (B). The tethers are tied to the bilateral rods at a level distal to the UIV pedicle screws with a torque of 200 Nm with a tape tightener (C). Arrows show the tape passing under the UIV+1 lamina. Source: Yagi et al. Clin Spine Surg 2022;35(5):E496-E503. Copyright 2022. Reprinted with permission of Wolters Kluwer Health, Inc.
Tables
Study Study Design Level of Evidence Patients, n Patient Population Mean Age, y Mean Follow-Up, mo Tether Clinical Outcome Alluriu et al27 Retrospective cohort III 83 ASD patients 64 20.3 Semitendinous allograft PJK present in 33% (16/49) of patients in tether group and 32% (11/34) of patients in control group (P = 0.31); PJF occurred in 18% (6/34) in control group but did not occur in tether group (P = 0.01) Buell et al28 Retrospective cohort III 120 ASD patients with instrumentation at >6 motion segments without transitional rods or hooks at UIV; all had lower-thoracic UIV (T9-T11) 67 28 Mersilene polyethylene tape Tethers significantly reduced PJK in ASD patients with lower-thoracic UIV (OR = 0.063, 95% CI = 0.016–0.247, P < 0.001); risk factors for PJK in patients with tether were greater postoperative lordosis of upper lumbar spine and greater UIV angle Buell et al29 Retrospective cohort III 184 ASD patients with instrumentation at >6 motion segments without transitional rods, hooks at UIV, or vertebral augmentation 66 20 Mersilene polyethylene tape PJK rates: 45.3% (29/64) in no-tether group; 34.4% (22/64) in tether-only group; and 17.9% (10/56) in tether with crosslink group; PJK rate was lower for all tethered (26.7%) vs no-tether groups (P = 0.011) Iyer et al30 Retrospective cohort III 108 ASD patients with >5-level fusion to the pelvis 55 17.6 Mersilene polyethylene tape Rates of PJK in tether group (27.3%) and no-tether group (28.6%) were similar (P = 0.827); tether was not protective against PJK Line et al31 Prospective cohort II 625 ASD patients with >5 levels fused posteriorly 58.6 31 Polyethylene tether assessed in the context of other PJK preventive approaches (cement, hook, and avoidance of overcorrection) If no PJF prophylaxis used and sagittal plane overcorrected, PJF rate was 24.2%; if PJF prophylaxis used, PJF rate was significantly lower (10.6%, P < 0.05) and further reduced to 9.9% if also not overcorrected; PJF rate similar (P > 0.05) for cement (12.1%), hooks (7.0%), and tether (16.1%) Pham et al32 Retrospective case series IV 4 ASD patients with long-segment spinal fusion to the upper-thoracic spine 60 5.5 Semitendinous allograft None of the 4 patients developed PJK at 5.5 mo follow-up; mean PJA increased by 3° Rabinovich et al33 Retrospective cohort III 184 ASD patients with >5 level fusions to the pelvis 67 45.4 Mersilene polyethylene tape PJK rates: 60.7% (37/61) in no-tether group; 35.7% (15/42) in tether-only group; and 23.3% (10/43) in tether with crosslink group; rate of PJK in no-tether group was significantly higher than in tether group (60.7% vs 29.4%, P < 0.001); PJK rate was lower in tether with crosslink vs no-tether group (P = 0.016); Rabinovich et al34 Retrospective case series IV 71 ASD patients with long-segment spinal fusion 66 14 Polyethylene-terephthalate tape PJK occurred in 15%; PJA increased by mean of 4°; rates of symptomatic PJK and revision for PJK were 8.8% and 2.9%, respectively Rodnoi et al35 Retrospective cohort III 43 ASD patients with fusion from throacolumbar junction (T9–L1) to the pelvis 69 24 Mersilene polyethylene tape Rate of PJK was significantly higher in no-tether group (17/20; 85%) vs tether group (10/23; 43.5%; P = 0.01); rate of PJF was significantly lower in tether group (0/23, 0%) vs no-tether group (7/20, 35%; P = 0.003) Rodriguez-Fontan et al36 Retrospective cohort III 80 ASD patients with >3 levels fused posteriorly 62.3 24 Mersilene polyethylene tape PJK rate at 2-y follow-up was 15% in tether group and 38% in no-tether group (OR = 0.28, P = 0.04); higher latent period to PJK for tether vs no-tether group (20 vs 7.5 mo, P = 0.018); tether reduced PJK risk after adjusting for confounders (age >55 y, 7–15 levels fused, thoracic UIV, BMI >27, osteoporosis) Safaee et al37 Retrospective cohort III 200 ASD patients undergoing instrumented fusion 64 Minimum 6 Soft sublaminar cable Mean change in PJA was 6° in tether group vs 14° in no-tether group (P < 0.001); PJF rate in tether group was 4% (4/100) vs 18% (18/100) in no-tether group (P = 0.002) Safaee et al38 Retrospective cohort III 319 ASD patients undergoing instrumented fusion 65 Minimum 12 Soft sublaminar cable Rate of reoperation for PJF significantly lower in tether group (8/242, 3.3%) vs no-tether group (12/77, 15.6%; P < 0.001); for patients with upper-throacic UIV, rate of PJF was 0% in tether group vs 6.7% in no-tether group (P = 0.014); for patients with lower-thoracic UIV, rate decreased from 21.3% to 5.3% (P = 0.001); on multivariate analysis, only use of tether and greater number of fused levels were associated with reductions in the rate of reoperation for PJF Viswanathan et al39 Prospective cohort II 40 ASD patients undergoing thoracic to ilium instrumentation 64 12 (median) Braided sublaminar band PJK developed in 3 of 40 (7.5%) patients; no instances of PJF; 3 procedure-related complications (2 CSF leaks and 1 transient neurological deficit) Yagi et al40 Retrospective cohort III 64 ASD patients undergoing instrumented fusion from lower throacic spine to sacrum 67 Minimum 24 Sublaminar polyethylene band PJA was significantly greater in the no-tether group (17° vs 8°, P < 0.001); incidence of PJF was lower in the tether group (3% vs 25%, P = 0.03), with an OR of 0.1 (95% CI: 0.0–0.8, P = 0.03) Zaghloul et al41 Retrospective case series IV 23 ASD patients treated with long-segment posterior instrumented fusion 63 11.9 Mersilene polyethylene tape None of the patients had developed PJK (0%) as of last follow-up Abbreviations: ASD, adult spinal deformity; BMI, body mass index; CI, confidence interval; CSF, cerebrospinal fluid; OR, odds ratio; PJA, proximal junctional angle; PJF, proximal junctional failure; PJK, proximal junctional kyphosis; UIV, upper-most instrumented vertebra.
Study Tether Technique Pham et al32
Alluriu et al27A No. 2 Ethibond double filament suture was used to create a modified locking Krackow weave at both ends of a cadaveric semitendinous tendon graft. This graft was then passed between the spinous processes from 1 level above the UIV to 1 to 2 levels below the UIV. The ends of the Ethibond suture were then tied together alone or tied together over a crosslink. Buell et al28
Buell et al29
Line et al31
Rabinovich et al33Two different techniques were used. (1) A high-speed drill was used to create holes through the base of the spinous processes at the UIV+1 and UIV-1. A polyetheylene Mersilene tape on a blunt needle was passed through the holes created in the UIV+1 and UIV-1 spinous processes and tied securely. (2) A high-speed drill was used to create a hole through the base of the spinous processes at the UIV+1. A polyetheylene Mersilene tape on a blunt needle was passed through the hole created in the UIV+1 spinous process. The tether was tied to a crosslink placed spanning the rods between UIV-1 and UIV-2. The crosslink was distracted caudally to tension the tether and secured to the rods. Iyer et al30 A 5-mm Mersilene tape on a curved needle was passed through the spinous process of the UIV+1 (Figure 1). A drill was used to create a hole through the spinous process if the needle could not be readily passed. The tether ends were then passed around the spinal rods below the pedicle screws at the UIV in a loop fashion, tensioned manually using a slip knot, and tied. This process was repeated, placing the tape through the spinous process of the UIV and securing the tape below the pedicle screws at the UIV-1. Rabinovich et al34 The VersaTie tether system (NuVasive) was used (Figure 2). A high-speed drill was used to create a hole through the base of the spinous process at the UIV+1 (and in some cases also at the UIV+2). A polyetheylene-terephthalate tape on a blunt needle was passed through the interspinous ligament between the UIV and UIV-1, then either passed through the spinous process at the UIV+1 alone or woven through UIV+1 and UIV+2, then passed back through the interspinous ligament between the UIV and UIV-1. The tether ends were then each passed through supplied tether rod connectors, which were then attached to the rods between the UIV and UIV-1 or between the UIV-1 and UIV-2. The VersaTie tower was then used to tension the tethers before final fixation of the tether to the connector device. Rodnoi et al35 A towel clamp was used to create a hole through the base of the spinous process at the UIV+1 (Figure 3). A polyethylene suture tape was passed through the spinous process at the UIV+1, and the ends of the tape were then tied over a crosslink placed spanning the rods between the UIV and UIV-1. A compressor was then used to distract the crosslink in order to tension the tape before the connector was final tightened. Zaghloul et al41
Rodriguez-Fontan et al36A 5-mm-wide Mersilene tape was passed through or looped around the supra-adjacent level spinous process (UIV+1), then looped in a figure-of-8 around the infra-adjacent spinous process (UIV), then tied to the rods below the screws at the UIV or tied to a crosslink attached to the rods between the UIV and UIV-1. Safaee et al37
Safaee et al38The Medicrea tether system was used (Figure 4). A high-speed drill was used to create holes through the base of spinous processes at UIV, UIV+1, and UIV-1. A soft sublaminar cable was passed through these holes in a mirrored weave pattern. Two cables were used (one on each side) and were pulled tightly to achieve the desired tension. The cables were then locked onto the rods using the supplied connectors. Viswanathan et al39 The Jazz system (Implanet America) was used. Bilateral hemilaminotomies were performed to widen the intralaminar spaces proximal and distal to the UIV+1 laminas with a power burr and Kerrison rongeur. The underlying ligamentum flavum was removed using Kerrison rongeurs until the underlying dura was exposed. The 2 braided polyester sublaminar bands were then carefully passed under the lamina from inferior to superior. Neuromonitoring was utilized. The sublaminar bands were connected to the rods at the UIV level and hand-tensioned using a tensioner device. Yagi et al40 Ligamentum flavum proximal and distal to the UIV lamina was partially removed using a Kerrison rongeur or high-speed drill (Figure 5). A 5-mm polethylene sublaminar band was then passed under the lamina of the UIV+1. The tether was attached to the rods bilaterally at a level distal to the upper-most pedicle screws with a torque of 200 Nm using a tape tighetener. Abbreviation: UIV, upper-most instrumented vertebra.
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