Sublaminar Wires Research Articles

Isola spinal instrumentation system for idiopathic scoliosis.

Since the definition of three-dimensional components of the scoliotic deformity, there have been important improvements in the surgical treatment of the problem. A derotation maneuver was proposed as a treatment option with CD instrumentation, but the reports of imbalance and decompensation with this system repopularized sublaminar wiring and translation as a corrective maneuver. Isola spinal instrumentation is one of the modern systems that utilizes vertebral translation instead of rod rotation. This study analyzes the results of 24 patients with idiopathic scoliosis who had been followed up for at least 2 years, and were surgically treated with titanium Isola Spinal Instrumentation in the Department of Orthopaedics and Traumatology, Ankara Social Security Hospital. Patients were grouped according to the King-Moe classification. Patients with type III, IV or V curves received only posterior instrumentation while this procedure followed anterior release and discectomy in the same session in patients with type I or II curves. A translation maneuver was utilized in the correction of scoliotic curves using the cantilever technique, either alone or supplemented by sublaminar wiring with Songer multifilament titanium cables. This study aimed to elucidate the effects of this technique in the frontal and sagittal plane curves and the trunk balance. The balance was analyzed clinically and radiologically by measurement of the lateral trunk shift (LT), shift of stable vertebra (SS), and shift of head (SH) in vertebral units (VU). The postoperative correction was significant in the frontal plane for all types of curves (p < 0.05). The postoperative correction was 80.9% +/- 9.5% in type III curves. Overall, the mean Cobb angle of the major curve value in the frontal plane was 66.9 degrees +/- 18.8 degrees, and it was corrected by 62.8% +/- 20.1%. The correction loss of Cobb angles in the frontal plane was 5.4 degrees +/- 5.5 degrees at the last follow-up visit. A normal physiologic thoracic contour (30 degrees - 50 degrees) was achieved in 83.3% of the patients and normal lumbar contour (40 degrees - 60 degrees) in 66.7% of the patients in the sagittal plane. The correction was found to be significant in all balance values (p < 0.05). The postoperative correction in LT values correlated with the correction of the Cobb angle values in the frontal plane. All patients had complete balance (SH: 0 VU and SS: 0 VU) or balanced curves (0 VU < SH, SS < 0.5 VU).Finally, the study concluded that the translation maneuver, especially when used with the cantilever technique, resulted in high correction rates in the frontal plane. Additionally, the technique was also successful in obtaining normal sagittal contours and correcting balance values.

Spinal Cord Monitoring in Neuromuscular Scoliosis

This article reviews the use of spinal cord monitoring in neuromuscular scoliosis, a condition having a higher incidence of true positive results than idiopathic scoliosis. While somatosensory cortical evoked potentials (SCEP) are unreliable, somatosensory spinal evoked potentials (SSEP) are possible to obtain in most cases and a method using an epidural electrode is described. The '50% rule' is satisfactory having good specificity and sensitivity with it rare for post-operative paralysis to have occurred undetected. The spinal cord in these cases appears to have increased susceptibility particularly during the passage of sublaminar wires with the incidence of complications reduced using modern instrumentation.

Translaminar screws in the atlas.

This was a retrospective review of a new surgical technique. To describe a new method of fixation augmentation in posterior C1-C2 spondylodesis. Posterior atlantoaxial spondylodesis using transarticular screws is often supplemented with sublaminar wires to enhance stability. This technique is not possible if the arch of C1 is deficient. A method of stabilizing the segment and the graft was developed, and the early results were reviewed. Five patients with a deficient posterior arch of the atlas, who also needed atlantoaxial spondylodesis, were reviewed. In each patient, fixation was augmented with translaminar screws that attached the graft to the arch of C1. In all five patients, solid arthrodesis was achieved, and all had substantial relief of pain. There were no neurologic complications or failures of fixation. The method of fixation of graft to the atlas using translaminar screws is a safe and reasonable alternative to external halo immobilization or more extensive surgery, such as occiput to C2 fusion.

Torsional rigidity of scoliosis constructs.

A biomechanical study of the rigidity of various scoliosis constructs instrumented with and without caudal pedicle screw anchors and with none, one, or two cross-link devices. To determine whether the increased torsional rigidity provided by distal pedicle screw fixation might make cross-linking unnecessary. Pedicle screws and cross-linking devices have been shown to increase the structural rigidity of spinal constructs. Their relative contributions to scoliosis construct rigidity has not been determined. "Short" (T2-T11) and "long" (T2-L3) scoliosis constructs were mounted on an industrially fabricated spine model and tested in a hydraulic testing machine. Four different short and four different long constructs were tested: hooks only, hooks with concave side thoracic sublaminar wires, hooks with distal pedicle screw anchors, and hooks, distal pedicle screw anchors, and concave thoracic sublaminar wires. There were four iterations for each construct tested: no cross-links, one superior cross-link at T4-T5, one inferior cross-link at T9-T10, and two cross-links. Torsional rigidity was tested by applying a rotational torque at T2. Vertebral body motion was recorded with a three-dimensional video analysis system. Constructs with distal pedicle screws were statistically more rigid in torsion than those with hooks as distal anchors. The additional torsional rigidity from one or more cross-links was negligible compared with that provided by pedicle screws. With pedicle screws as distal anchors in scoliosis constructs, cross-linking with one or two devices adds very little additional rotational stiffness and may be unnecessary in many cases.

Safety of sublaminar wires with Isola instrumentation for the treatment of idiopathic scoliosis.

To investigate the incidence of acute neurologic complications of use of sublaminar wires with third-generation spine instrumentation for the treatment of idiopathic scoliosis. To assess the safety of sublaminar wires in the surgical treatment of idiopathic scoliosis. The use of sublaminar wires in spine deformity for neuromuscular scoliosis and the Luque system has been reported. Use of sublaminar wires is an integral part of the technique in the surgical treatment of spine deformity with Isola instrumentation (AcroMed, Cleveland, OH). To date, the safety of this technique has not been documented. The average age of the patients was 37 years (range, 11-74 years). Preoperative diagnosis was adolescent idiopathic scoliosis in 75 patients and adult idiopathic scoliosis in 66. One hundred nine were primary surgeries, and 32 were revision. Detailed evaluation of the curve type, curve magnitude, number of vertebrae instrumented, level of vertebrae wired, postoperative neurologic deficit, and the findings of intraoperative spinal cord monitoring was performed. Wires were always passed just before corrective maneuvers were performed. A total of 1366 wires were placed, 65% (n = 888) in the thoracic region, 22% (n = 300) in the thoracolumbar, and 13% (n = 178) in the lumbar. No permanent change in intraoperative spinal cord monitoring was detected. Stagnara wake-up test was performed in all patients. No patient with adolescent idiopathic scoliosis had neurologic complication. Two adults underwent revision surgery and had transient dysesthesia in the leg, which completely resolved with observation. Despite the increasing complexity of spinal instrumentation systems, sublaminar wire placement is a safe and useful adjunct in the surgical treatment of neurologically intact patients with idiopathic scoliosis.

Occipitocervical stabilization for myelopathy in patients with rheumatoid arthritis. Implications of not bone-grafting.

Approximately 0.9 percent of the white adult population of the United States and 1.1 percent of the adult population in Europe are affected by seropositive rheumatoid arthritis. As many as 10 percent of those patients may need an operation for atlantoaxial subluxation. Severe instability, especially when associated with vertical subluxation of the odontoid process, can result in progressive cervical myelopathy. Typically, occipitocervical fixation has been performed for these patients with use of autograft bone to achieve long-term stability through a solid fusion. Harvesting the bone graft increases the operative risk to the patient and may result in increased morbidity. In our experience, patients who have had no clear radiographic evidence of fusion following use of occipitocervical instrumentation seemed to have done as well as those who have had obvious fusion. One assumption is that the clinical improvement might be attributable simply to stabilization of the joint rather than to osseous fusion. A longitudinal study was performed on patients with rheumatoid arthritis who required an operation because of craniocervical or upper cervical instability. The results of clinical, radiographic, functional, and self-evaluations were studied to determine the efficacy of treatment and to compare the outcomes of bone-grafting with those of procedures done without bone-grafting in a group of 150 patients who underwent posterior occipitocervical stabilization with use of a contoured metal implant (a Ransford loop) that was affixed by sublaminar wires. Internal fixation was performed in 120 patients without bone-grafting and in thirty patients with use of autogenous bone-grafting. Preoperatively, 23 percent (thirty-five) of the 150 patients had mild neurological involvement (class II, according to the system of Ranawat et al.), 45 percent (sixty-eight) had objective findings of weakness and long-tract signs but were able to walk (class III-A), and 29 percent (forty-three) were quadriparetic and unable to walk (class III-B). The age of the patients at the time of the operation ranged from twelve to eighty-three years (mean, sixty-two years). There were significant improvements in postoperative Ranawat classes at all time-periods (range, p < 0.00005 to p = 0.0066) and in patient ratings of neck pain (range, p < 0.00005 to p = 0.0044) compared with preoperative scores. With the numbers available, there were no significant differences between the patients managed with a graft and those managed without grafting with respect to survival after the operation, Ranawat class, head or neck-pain rating, presence of subaxial abnormalities, radiographic craniovertebral motion, or vertical subluxation. Overall mortality at one month was 10 percent (fifteen of 150), although this value varied directly with the degree of preoperative disability. A second cervical spine operation was required in 11 percent (sixteen) of the 150 patients. While patients who have rheumatoid disease with anterior atlantoaxial subluxation should be treated with posterior atlantoaxial arthrodesis with use of bone-grafting and internal fixation, we believe that those who present with vertical instability and multi-level involvement can be treated with posterior occipitocervical stabilization with use of a contoured occipitocervical loop and sublaminar wire fixation without bone-grafting. Furthermore, we believe that the use of preoperative traction, bone cement, or a postoperative halo vest is unnecessary. Avoiding the harvesting of autogenous bone for grafting reduced the morbidity of this operation without compromising the outcome in these already sick patients.

Scoliosis correction maintenance in skeletally immature patients with idiopathic scoliosis. Is anterior fusion really necessary?

A retrospective evaluation of the occurrence of the crankshaft phenomenon in skeletally immature patients with idiopathic scoliosis. To determine what factors, if any, contribute to a decreased occurrence of crankshaft phenomenon in patients treated with posterior surgery only. Reports have described the progression of scoliotic deformity, termed the crankshaft phenomenon, in a region of solid posterior arthrodesis in skeletally immature patients. This has led some authors to advocate the use of concomitant anterior discectomy and fusion to prevent crankshaft. From 1989 through 1994, 18 Risser 0 patients with thoracic or thoracolumbar idiopathic scoliosis underwent Isola (De Puy-Acromed, Raynham, MA) posterior instrumentation and fusion. They were assessed for evidence of the crankshaft phenomenon, identified by coronal plane deformity progression of 10 degrees or more, or a rib vertebra angle difference of 10 degrees or more. The average age of the patients was 12.5 years (range, 10.5-15.5 years), and the average follow-up period was 39 months (range, 24-68 months). Eleven patients (10 girls and 1 boy) had closed triradiate cartilage at the time of surgery. Their average Cobb angle was 62 degrees before surgery, 21 degrees after surgery, and 22 degrees at follow-up assessment. No patients in this group met the criteria for crankshaft. Seven patients (6 girls and 1 boy) had open triradiate cartilage at the time of surgery. Their average Cobb angle was 62 degrees before surgery, 18 degrees after surgery, and 20 degrees at follow-up evaluation. No patient had a 10 degrees or more increase in rib vertebra angle difference. One patient had more than a 10 degrees increase in her Cobb angle (11 degrees) from postoperative to latest follow-up assessment. Her instrumentation construct, performed in 1989, used sublaminar wires as the caudal anchors. Hooks and pedicle screws are now used. Two of the seven patients with open triradiate cartilage underwent surgery during or before their peak height velocity and displayed no evidence of crankshaft. No deaths, neurologic complications, or infections occurred in either group. These findings suggest that scoliotic deformity progression can be prevented in skeletally immature patients with idiopathic scoliosis as young as 10 years of age with the use of stiff segmental posterior instrumentation, without the necessity of concomitant anterior arthrodesis.

後方インストゥルメント使用により手術を行った脊椎カリエスの検討

Eleven patients with thoracic and lumbar tuberculosis were treated by anterior debridement and fusion combined posterior instrumentation. A one-stage surgery was done on seven patients and a two-stage surgery on four patients. Posterior instruments included seven ISOLA, three Luque rods with sublaminar wiring, and one Spine system. The average range of anterior fusion was 2.4 segments and that of the posterior fixation was 3.8 segments. Seven patients presented paraparesis before surgery and all improved after surgery. None showed persistent or recurrent tuberoculosis. Sagittal alignment, corrected after surgery, was not lost by more than 10 degrees in 10 patients but by 30 degrees in one patient treated with Luque rods. Solid bone union was obtained in all patients. Our study showed that anterior debridement and fusion combined with posterior instrumentation are useful for spinal tuberculosis.

Biomechanical evaluation of five different occipito-atlanto-axial fixation techniques.

The stabilizing effects of five different occipitocervical fixations were compared. To evaluate the construct stability provided by five different occipito-atlanto-axial fixation techniques. Few studies have addressed occipitocervical reconstruction stability and no studies to data have investigated anterior-posterior translational stiffness. A total of 21 human cadaveric spines were used. After testing intact spines (CO-C2), a type II dens fracture was created and five different reconstructions were performed: 1) occipital and sublaminar wiring/rectangular rod, 2) occipital screws and C2 lamina claw hooks/rod, 3) occipital screws, foramen magnum screws, and C1-C2 transarticular screws/rod, 4) occipital screws and C1-C2 transarticular screws/Y-plate, and 5) occipital screws and C2 pedicle screws/rod. Biomechanical testing parameters included axial rotation, flexion/extension, lateral bending, and anterior-posterior translation. Pedicle screw fixation demonstrated the highest stiffness among the five reconstructions (P < 0.05). The two types of transarticular screw methods provided greater stability than hook or wiring reconstructions (P < 0.05). The C2 claw hook technique resulted in greater stability than sublaminar wiring fixation in anterior-posterior translation (P < 0.05). However, the wiring procedure did not significantly increase the stiffness levels beyond the intact condition under anterior-posterior translation and lateral bending (P > 0.05). C2 transpedicular and C1-C2 transarticular screws significantly increased the stabilizing effect compared to sublaminar wiring and lamina hooks. The improved stability afforded by C2 pedicular and C1-C2 transarticular screws offer many potential advantages including a high rate of bony union, early ambulation, and easy nursing care. Occipitocervical reconstruction techniques using C1-C2 transarticular screws or C2 pedicle screws offer biomechanical advantages compared to sublaminar wiring or lamina hooks. Pedicle screw fixation exhibited the highest construct stiffness among the five reconstructions.

A new approach to scoliosis.

Despite the advantages that new derotation-based systems have brought to the treatment of scoliosis, the debate continues, especially regarding adolescent idiopathic scoliosis. Problems like decompensation, junctional kyphosis, and insufficient sagittal plane alignment are met with new proposals. We now are using a technique and system, the Ibn-I Sina Spinal System (IBS), that we think is able to overcome these problems. It makes use of sublaminar wires, hooks, screws, and rods for correction. The main innovation is that the major corrective force is a controlled translation force acting simultaneously on all segments of the curve. A retrospective assessment of 25 patients treated with this system showed that besides dealing well with decompensation and junctional kyphosis problems, the technique was superior in sagittal plane adjustments, mainly in that it carried the normal kyphosis to its physiologic location. IBS has proved easy and successful in scoliosis treatment, especially with lordotic rigid curves. We encountered no neurologic injury or instrument failure. In addition to these advantages, ease of preoperative planning and application, decreased operation time, easy removal or revision, and versatility and safety of the system has made the Ibn-I Sina Spinal System (IBS) a treatment of choice, especially for adolescent idiopathic scoliosis cases, in some centers in Turkey.

Trauma in congenital atlanto-axial dislocation.

Congenital atlanto-axial dislocation (AAD) usually presents with chronically progressive compression of the cervico-medullary junction. However, even a minor trauma can cause acute compression with development of quadruplegia and respiratory impairment. At times these may be transient, or trauma may aggravate the compression and lead to progressive quadriplegia. Of 60 children seen with congenital AAD, in 15 it had been associated with trauma. Nine of these 15 AADs were of the mobile variety, and 6 of the fixed variety with odontoid invagination. In 6 children with mobile and 2 with fixed AAD, trauma led to an acute manifestation with quadriplegia. Three of the children also experienced respiratory distress and needed ventilatory support. All 15 were initially treated with skull traction. Once the condition was stabilised, those with the mobile variety underwent fixation in a reduced position and grafting. One of the children with respiratory distress died within 2 days of admission. In 4 of them, sublaminar wiring between C1 and C2 was carried out, and in 3 others wiring between occiput and base of spinous process of C2 was performed. In 1 case a Hartshill loop was used. Among the children with fixed AAD, reduction of the odontoid invagination was obtained in 2, and they underwent fusion. In 4 cases with unsatisfactory reduction, posterior decompression of the foramen magnum and the fused posterior arch of the atlas was performed. The results depended on the degree of neurological deficit in each child.

Techniques of posterior subaxial cervical fusion

Techniques of posterior cervical fixation have been augmented and refined over the past century to treat more effectively cervical instability arising from trauma, neoplasia, inflammatory conditions, and degenerative disease. Although adequate for many indications, posterior subluxation stabilization constructs perform best when used primarily to address flexion-type injuries. The integrity of the dorsal tension band is thereby reestablished. Posterior cervical fixation techniques may be subdivided into three general categories: (1) wire or cable constructs (including various interspinous wiring, facet wiring, sublaminar wiring, and wire/polymethylmethacrylate techniques; (2) interlaminar clamps; and (3) articular mass platescrew devices. This article details these techniques and their variations and presents a rationale for choosing a construct.

Technique of occipitocervical fusion with a threaded steinmann pin

The threaded Steinmann pin technique of occipitocervical fusion represents an excellent method for treating occipitocervical instability, failed C1–C2 fusion, or atlantoaxial instability in situations in which the posterior arches of C1 or C2 are deficient, fractured, or absent. Immediate rigid internal fixation is achieved by securing a wide diameter, contoured, threaded Steinmann pin or grooved titanium rod to the occipitocervical region by means of suboccipital and sublaminar wires. Fusion is facilitated with autologous bone graft and a cervical orthosis.

Stability of different wiring techniques in segmental spinal instrumentation. An experimental study.

The pullout force of sublaminar and transspinous wires for segmental instrumentation which had been inserted into different segments of human cadaver spines were compared. Four different types of wiring were tested: single and double sublaminar wires, button-wires according to Drummond's technique and button-wires with the additional use of two crimps for each spinous process. A total of 50 tests were performed. In all attempts the bone proved to be the limiting factor. None of the 300 fixed wires failed. Typical types of fractures appeared with different wiring techniques. There was no statistically significant difference between the sublaminar wiring techniques tested. However, there were significant differences between sublaminar and transspinous wiring. The transspinous techniques achieved between 30% and 45% of the pull-out strength of sublaminar techniques. The forces decreased with increasing cranialisation. In all techniques the values in the upper segment (D5-D3) were almost half those of the lower segment (L5-L3). The differences of the transspinous techniques increased cranially, in favour of the technique with additional crimps. Thus, the crimps have the strongest effect on weak spinous processes. This study demonstrates that in non-dynamic testing, the stability of the bone and not the type of wiring is the limiting parameter in segmental spinal stabilisation. As the wires are inserted in different areas, the transspinous technique shows significantly lower tension forces in comparison with sublaminar wiring.

Point of View: Mechanical Stability of the AO Internal Spinal Fixation System Compared With That of the Hartshill Rectangle and Sublaminar Wiring in the Management of Unstable Burst Fractures of the Thoracic and Lumbar Spine

Point of View: Mechanical Stability of the AO Internal Spinal Fixation System Compared With That of the Hartshill Rectangle and Sublaminar Wiring in the Management of Unstable Burst Fractures of the Thoracic and Lumbar Spine

Consensus Summary on the Diagnosis and Treatment of Osteoporosis

Consensus Summary on the Diagnosis and Treatment of Osteoporosis

NEUROLOGICAL DETERIORATION AFTER POSTERIOR WIRING OF THE CERVICAL SPINE

Posterior cervical wiring is commonly performed for patients with spinal instability, but has inherent risks. We report eight patients who had neurological deterioration after sublaminar or spinous process wiring of the cervical spine; four had complete injuries of the spinal cord, one had residual leg spasticity and three recovered after transient injuries. We found no relation between the degree of spinal canal encroachment and the severity of the spinal-cord injury, but in all cases neurological worsening appeared to have been caused by either sublaminar wiring or spinous process wiring which had been placed too far anteriorly. Sublaminar wiring has substantial risks and should be used only at atlantoaxial level, and then only after adequate reduction. Fluoroscopic guidance should be used when placing spinous process wires especially when the posterior spinal anatomy is abnormal.

Neurological deterioration after posterior wiring of the cervical spine

Posterior cervical wiring is commonly performed for patients with spinal instability, but has inherent risks. We report eight patients who had neurological deterioration after sublaminar or spinous process wiring of the cervical spine; four had complete injuries of the spinal cord, one had residual leg spasticity and three recovered after transient injuries. We found no relation between the degree of spinal canal encroachment and the severity of the spinal-cord injury, but in all cases neurological worsening appeared to have been caused by either sublaminar wiring or spinous process wiring which had been placed too far anteriorly. Sublaminar wiring has substantial risks and should be used only at atlantoaxial level, and then only after adequate reduction. Fluoroscopic guidance should be used when placing spinous process wires especially when the posterior spinal anatomy is abnormal.

P-4-466 - Multi-level anterior cervical arthrodesis and instrumentation: Outcome analysis

Occipito-cervical(OC) fusion is often practiced for congenital atlanto-axial dislocation (CAAD) and basilar invagination (BI) with claims of good long term outcome. Little has been discussed about the delayed complications following fusing occipital squama to cervical spine (OC fusion). We have described and analyzed delayed complications with OC fusion in our patients that helps us understand the underlying dynamics and biomechanics.Twenty seven patients of CAAD and BI underwent OC fusion (between 2008 and 11) after transoral odontoidectomy or direct posterior reduction with OC distraction. OC fusion was achieved using either sublaminar wiring or with precurved rods and screws or contoured loop. One patient was referred after OC fusion with contoured loop and wires with additional C1 laminectomy. The outcome (> 12 months) and delayed complications in these patients were analyzed.Five types of delayed complications were noticed in 6 of the 28 patients who underwent OC fusion. Five of 6 patients were adults. Vertical redislocation with posterior midline fusion (n = 2), adjacent level angular listhesis (n = 1) and swan neck deformity (n = 1) was seen in cases of OC fusion with sublaminar wires alone. Progressive C1 dislocation was seen in the lone patient who was referred after OC fusion with loop and wires. Vertical and angular dislocation was seen in 1 patient of OC fusion with precurved rod and screws.Progressive redislocation and adjacent level dislocation are delayed complications seen after OC2 fusion. These complications are more often seen in adults, especially with sublaminar wiring/semi rigid OC fixation.

Prevalence of segmental wire breakage using Cotrel-Dubousset instrumentation in the management of idiopathic scoliosis.

This is a retrospective radiographic and medical record analysis of 77 patients. To determine whether there is an increased prevalence of segmental sublaminar wire breakage associated with the knurled (diamond) pattern machined onto the Cotrel-Dubousset rod as opposed to a smooth rod. Segmental fixation of vertebral segments with sublaminar wires is a common surgical technique, and the use of sublaminar wires with a knurled Cotrel-Dubousset rod theoretically could cause premature wire breakage. Sixty-six patients with idiopathic scoliosis had the Cotrel-Dubousset (knurled rod) system and comprised the study group, and the Texas Scottish Rite Hospital system (smooth rod) was placed in 14 patients, who served as a control group. Serial radiographs after 3, 6, 12, and 24 months were reviewed. All patients had augmentation of their scoliosis constructs with 16-gauge sublaminar wires in the lumbar spine. Minimum follow-up period was 24 months. No wire breakage was noted in any patient. There is no increased likelihood that the knurled rod pattern will cause wire breakage, provided a solid fusion is obtained.