Removal of sublaminar wires after spinal fusion

Eighteen patients who had had spinal fusion using Harrington rods with sublaminar wires underwent removal of the implants because of tenderness over the implants. There were no important complications. At final follow-up, no patient had a change in neurological function as compared with the preoperative assessment, and all reported relief of the preoperative tenderness. We concluded that the removal of rods and sublaminar wires from patients who have had a spinal fusion is clinically safe and effective.     

Segmental spinal instrumentation without sublaminar wires

We have developed a method of segmental spinal instrumentation that precludes the passage of sublaminar wires, thus reducing the likelihood of neurological complications. The technique utilizes the base of the spinous process as the purchase site for segmental fixation and a newly developed button-wire implant. The technique and early experience with this method are described.     

Segmental spinal instrumentation without sublaminar wires

Summary We have developed a method of segmental spinal instrumentation that precludes the passage of sublaminar wires, thus reducing the likelihood of neurological complications. The technique utilizes the base of the spinous process as the purchase site for segmental fixation and a newly developed buttonwire implant. The technique and early experience with this method are described.

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Zusammenfassung Wir haben eine Methode der instrumentellen segmentalen Wirbelsäulenstabilisie-rung entwickelt, die die Verwendung wirbelbogenumgreifender Drähte vermeidet and dadurch die Wahrscheinlichkeit neurologischer Komplikationen herabsetzt. Diese Technik vermendet einen neuentwickelten Knopfdraht and wählt als Ort der Fixation die Basis des Dornfortsatzes. Die Technik dieser Methode and erste Erfahrungen werden mitgeteilt.

     

Does sublaminar wiring produce spinal stenosis?

Sublaminar wiring provides strong and effective fixation of the scoliotic or unstable spine, but its long-term effects on the spinal canal remain unknown. An animal model was developed to observe these effects on the growth and development of the immature spine over a two-year period. Laminar overgrowth occurred both longitudinally to produce a kyphoscoliosis and in the transverse plane to cause significant laminar thickening and growth into the spinal canal. However, the cross-sectional area of the spinal canal was not significantly compromised.     

Depth of intraspinal wire penetration during passage of sublaminar wires

A major concern with the use of sublaminar wires for segmental spinal instrumentation is the risk of neurologic compromise associated with repeated passage of wires through the epidural space. Because of the inability to visualize the wire tip during its sublaminar passage, the surgeon is unable to appreciate the depth of wire penetration (DOWP). The purpose of this investigation was to determine, through direct measurement, the depth of intraspinal penetration during the passage of sublaminar wires. Using their model, the authors have been able to define the optimal parameters for safe wire passage. Careful attention to maintaining contact between the wire tip and the under-surface of the lamina, using a wire of optimal configuration, will result in minimal DOWP and reduce the possibility of neurologic compromise.     

Delayed paraplegia complicating sublaminar segmental spinal instrumentation

The cases of two patients with delayed paraplegia after segmental spinal instrumentation with sublaminar wiring are reported. Both patients had complex spinal deformities and had transient neural deficits after the first-stage procedure of anterior release and spine fusion. They had uneventful spinal-cord monitoring during the second-stage procedure of posterior instrumentation and fusion, and function of the lower extremities was present immediately after that operation. Paraplegia then ensued, and was recognized thirty hours later in one patient and six days later in the other. Considering our reproducible and reliable experience (no false-negative results) with spinal cord monitoring in 307 operations, we propose that the delayed onset of paraplegia resulted from a progression of ischemic and edema-producing events that had not developed sufficiently intraoperatively to be reflected by the monitoring. The paraplegia became evident only when the subarachnoid space was obstructed because of progressive postoperative neural edema. The presence of sublaminar implants in narrow, kyphotic segments of the spinal canal probably exacerbated the neural irritation by dural impingement, which was seen myelographically.     

Nylon sublaminar straps in segmental instrumentation for spinal disorders

A new modification of segmental spinal instrumentation is in an early stage of research and development. Preliminary evidence is most encouraging with respect to the advantages of the relative safety of insertion of the nylon strap around the neural arch. The facility with which the insertion and tightening of the strap can be employed reduces the operation time significantly.     

Experimental study of removal of sublaminar wires after spinal fixation

The result of experimental study of removal of sublaminar wires was reported. The experimental shows that sublaminar wires when with drawn at 45-degrees is safer than that at 90-degrees. Because of bony fusion, clinically could be drawn out only vertically either by rolling it up ward or down ward confirmed that there is no difference between this two methods. The cut end of wire should be short and straight. All the fixing wires became useless because of their loosening. Impressions were found on the inner face of lamina, fibrous sheaths. There is no different reactions between twisted and parallel double wires, but we recommend double parallel wires.     

Spine fusion in cerebral palsy with L-rod segmental spinal instrumentation. A comparison of single and two-stage combined approach with Zielke instrumentation

The benefits of achieving rigid internal fixation and eliminating the need for postoperative external orthotic support with L-rod spinal instrumentation made it desirable for use in the surgical treatment of neuromuscular scoliosis. From May 1981 to May 1985, 31 severely involved cerebral palsy patients with progressive spinal deformity underwent posterior fusion and L-rod instrumentation. All patients except one were nonambulatory. Surgical indications included prevention of curve progression, correction of pelvic obliquity, and achievement of balanced spinal alignment in order to improve sitting balance and tolerance without external spinal orthotic support. Ten patients (Group I), with an average age of 15.2 years, with double major or flexible paralytic C-curves or scoliosis measuring less than 70 degrees, underwent posterior fusion and L-rod instrumentation only. Twenty-one patients (Group II), with an average age of 22.1 years, with thoracolumbar, lumbar, or rigid paralytic C-curves or scoliosis measuring greater than 70 degrees, underwent initial anterior release, bone grafting, and Zielke instrumentation followed by second-stage L-rod instrumentation. In Group I, scoliosis averaged 57 degrees and postoperatively 27 degrees (53% correction). In Group II, scoliosis averaged 88 degrees and postoperatively 36 degrees (63% correction). Fifteen Group II patients had posterior fusion extend into the sacrum using the Galveston technique. Six Group II patients were not fused into the sacrum. Scoliosis and pelvic obliquity were corrected in both groups. Torso decompensation improved to 2.7 cm in the Galveston group, but increased to 5.6 cm at follow-up in the patients not fused into the sacrum.(ABSTRACT TRUNCATED AT 250 WORDS)     

Segmental spinal instrumentation with sublaminar wires. A critical appraisal

Fifty-eight patients who had scoliosis or kyphosis of varying etiologies were followed for a minimum of two years (average, forty-four months) after segmental spinal instrumentation using sublaminar wires. In eight (19 per cent) of the patients who had been operated on for scoliosis one or both rods broke. The average time that had elapsed before the breakage was discovered was twenty-three months. None of the patients in whom a rod had broken had had postoperative immobilization or a first-stage anterior fusion, and only one had had supplementary grafting with banked bone. Instrumentation to the pelvis was also associated with a greater incidence of broken rods. The use of supplementary grafting with banked bone or the use of postoperative immobilization significantly decreased the loss of postoperative correction. Preliminary anterior spinal fusion helped prevent breakage of rods but not loss of correction. It was concluded that postoperative immobilization and use of large amounts of supplementary bone graft lead to better results when using this implant system.     

Idiopathic scoliosis posterior spine fusion with Harrington rod and sublaminar wiring

The Harrington-sublaminar wiring technique has been used to treat idiopathic scoliosis for over 6 years. In all cases, satisfactory correction was obtained. The advantages of this technique include biomechanically stable fixation, elimination of a postoperative support or simple immobilization in removable underarm orthoses, and the ability to correct a two-plane deformity (i.e., lordoscoliosis). The potential disadvantages include increased operating time over Harrington rod alone, possible neural injury, and failure of instrumentation.     

Spinal arthrodesis for spinal deformity using posterior instrumentation and sublaminar wiring

Summary One hundred consecutive patients with spinal deformity due to various diagnoses were treated by posterior spinal arthrodesis with instrumentation and multiple sublaminar wires. Both the Harrington and Luque rodding systems were used. A total of 1128 wire loops were passed. No patient developed paraparesis or paraplegia, but three had transient sensory disturbance. There were no cases of broken rods or wires. Forty-five of the patients had no postoperative support. This worked well for neuromuscular scolioses, but for idiopathic scoliosis there was a disturbing loss of correction in many cases. Fusion to the sacrum was best accomplished with the Galveston technique, other methods having a high rate of pseudarthrosis. The main benefits appeared to be the ability to stabilize neuromuscular patients without the use of external immbolization, and the correction of thoracic lordosis.Supported in part by the Medical Education and Research Association of Gillette Children's Hospital Read in part at: Scoliosis Research Society, Orlando, Florida, September, 1984. S.I.C.O.T., London, England, October, 1984     

Craniocervical fusion for rheumatoid arthritis: comparison of sublaminar wires and the lateral mass screw craniocervical fusion

The majority of rheumatoid arthritis patients with C1/2 instability causing neck pain and neurological compromise can be treated with unisegmental fusion. However, a minority will require decompression and more extensive craniocervical fusion. Two cohorts of patients with rheumatoid arthritis requiring decompression and craniocervical fusion were included in a retrospective study comparing sublaminar wiring (Ransford Loop, n = 10, follow-up = 36 +/- 9.5 months) and lateral mass screws (Cervifix system, n = 11; follow-up = 39.7 +/- 7.9 months). Both cohorts of patients experienced significant improvements in high cervical pain scores [McGill 5-point score; preop = 4.5 +/- 0.75 for Cervifix and 4.5 +/- 0.75 for Ransford loop; postop = 1.17 +/- 0.9 (p = 0.003) for Cervifix (at 39.7 months +/-7.9) and 2.8 +/- 1.6 (p = 0.011) for Ransford loop (at 36 +/- 9.5 months)]. Lateral mass screws for craniocervical fusion (seven out of 11 pain free) appear to produce better early results for rheumatoid arthritis patients suffering high cervical neck pain than sublaminar wire techniques (three out of 10 pain free).     

Mechanisms of curve progression following sublaminar (Luque) spinal instrumentation.

Fifty-two patients with Luque instrumentation were reviewed for spinal deformities. Forty-two patients were reviewed during 1 year (longest 7.2 years) at follow-up. Two patients were included who lost correction within 1 year (both 8 months). Follow up averaged 2.9 years. Curve causes primarily were neuromuscular but included one was caused by idiopathic scoliosis, four by Scheuermann's disease, and 1 by post-laminectomy kyphosis. The Cobb angle progressed in 45% of patients postoperatively. Factors contributing to progression included progressive vertebral rotation or the crankshaft phenomenon (11), wire pull out (7), progressive pelvic obliquity (4), rod bending (3), pseudarthrosis (2), and rod migration (2). Factors correlating with progression were kyphosis, postoperative curve greater than 35 degrees, preoperative curve greater than 60 degrees, and not fusing to the pelvis in nonambulators. Crankshaft was common in patients Risser II or less but did not occur in more mature patients.     

Risks and cost-effectiveness of sublaminar wiring in posterior fusion of cervical spine trauma

A report on the use of sublaminar wiring in the fusions of 34 patients with cervical spine injuries is given. No neurologic deficits were incurred in the use of this technique. There were no wire failures nor clinically significant complications. When compared with other forms of instrumentation to achieve similar results, the use of sublaminar wire is the most cost-effective.     

Neuropathologic changes with experimental spinal instrumentation: transpedicular versus sublaminar fixation.

Fifty-six mature beagles underwent lumbar spine destabilization, followed by fusion using four techniques. Spinal cord neuropathologic analysis was carried out to determine the number of abnormalities within each group. Group I (n = 14) had posterolateral bone grafting without instrumentation. Group IIa (n = 14) had Cotrel-Dubousset (CD) pedicle screws and rods. Group IIb (n = 14) had Steffee pedicle screws and plates. Group III (n = 14) had sublaminar wires and rods. All of the animals remained clinically neurologically normal throughout the 6 months of the study. The incidence of moderate to severe neuropathologic changes was 21% in Group I, 18% in Group II, and 64% in Group III. Thus, a significantly higher percentage of neuropathologic abnormalities occurred with sublaminar instrumentation than with no instrumentation (p = 0.027), or with transpedicular instrumentation (p = 0.027). In this controlled animal study, the theoretical advantage of pedicle screws, which should not violate the spinal canal, over sublaminar devices, which must enter the canal, was confirmed.     

A biomechanical study of 3 different types of sublaminar wire used for constructs in the thoracic spine

A biomechanical study was carried out on 3 different types of sublaminar wire used in constructs to secure the thoracic spine: stainless steel monofilament wire (steel wire), titanium cable (cable), and ultra-high molecular weight polyethylene tape (tape). Two experiments were carried out. Experiment 1: Thirty-one fresh human thoracic vertebrae classified as osteoporotic (bone mineral density of <0.8 g/cm2) were used. The steel wire, cable, or tape was placed sublaminarly and a tensile force was applied until the steel wire, cable, or tape cut 5 mm through the lamina, and the force at this point was noted. Experiment 2: Seven fresh human thoracic spines (T7-T10) were biomechanically tested as follows: axial compression (250 N), flexion (7.5 Nm), extension (7.5 Nm), left lateral bending (7.5 Nm), right lateral bending (7.5 Nm), left axial torsion (10 Nm), and right axial torsion (10 Nm). This sequence was applied to the intact spine. The spine was then de-stabilized and then restabilized using one or other of the 3 different types of sublaminar wires. The biomechanical testing was then repeated on the restabilized spine and stiffness curves were generated. In the laminar cut-through test, the cut-through force for tape was higher than that for either steel wire or cable. In the biomechanical stiffness testing, there was no significant difference between the 3 different sublaminar wiring constructs in any of the loading modes tested. The results of both experiments suggest that tape is as good, if not better, than steel wire or cable as a sublaminar wiring construct material.