Sublaminar Wires Research Articles

Rigid Versus Nonrigid Occipitocervical Fusion

Retrospective data review. To report clinical outcomes of both rigid and nonrigid occipitocervical (OC) fusion constructs of a multicenter cervical spine study group. The OC junction is susceptible to a wide variety of pathologic conditions that predispose it to instability. The need for arthodesis in symptomatic or neurologically unstable cases has led to the development of a variety of fusion techniques that can be classified as either nonrigid fixation techniques, such as sublaminar wiring or onlay bone grafting, or rigid internal fixation constructs, such as screws with plate or rods. Rigid fixation provides immediate stability and eliminates the need for external fixators, that is, halo-vest. Although a rigid construct would seem to confer several advantages over a nonrigid construct with external inmobilization supplementation, comparative clinical data are is lacking. A clinical comparison of the rigid and the nonrigid forms of OC fusion was done retrospectively from the data of a multicenter cervical spine study group. A total of 71 occipitocervical fusion patients were identified: 25 with a nonrigid technique and 46 with a rigid construct. Average follow-up time was 6.3 months with a range of 1.5 to 36 for the rigid construct cohort and 15.7 months with a range of 1 to 36 months for the nonrigid cohort. Complications were recorded and correlated to the type of fixation and the type of external immobilization used. A χ analysis was done to evaluate the significant differences between complication rates of both the groups, that is, rigid and nonrigid constructs. Twenty-five nonrigidly fused patients had a complication rate of 48%, whereas 46 rigidly fused patients had a complication rate of 10% (P<0.01). Rigid forms of internal fixation for OC fusion has a significantly lower complication rate in short term. In addition to the many advantages of a rigid occipitocervical construct, the clinical complication rates are statistically significantly lower versus a nonrigidly fixed construct.

Hooks and Wires—Tried and True Plus How To

Fixation of the scoliotic spine can be achieved through the use of hooks and wires. These "tried and true" forms of fixation are discussed less commonly in the current era of focus on pedicle screw fixation. Sublaminar wires are still commonly used for neuromuscular scoliosis, in unusual curves, and at the apices of moderate curves. With careful attention to the technique, sublaminar wires can be safe and versatile. Hook fixation is generally expedient and safe. Both types of fixation are considerably less expensive than pedicle screws. Technical pearls and pitfalls are reviewed.

Pitfalls in pedicle subtraction osteotomy using sublaminar wire system for kyphosis associated with osteoporosis

Pitfalls in pedicle subtraction osteotomy using sublaminar wire system for kyphosis associated with osteoporosis

History of Spinal Deformity Surgery Part II: The Modern Era

Spinal deformity is one of the oldest known diseases that date back thousands of years in human history. It appears in fairy tales and mythologies in association with evil as its dramatic appearance in patients suffering from the disease easily lent itself to be thought of as a form of divine retribution. The history of spinal deformity dates back to prehistoric times. The early attempts to treat patients suffering from this disease started from Hippocrates age. Side traction or axial traction and cast immobilization were the only possible option prior to the discovery of anesthesia. The first surgical attempts to correct scoliosis occurred in the mid 19 th century with percutaneous myotomies of the vertebral musculature followed by postoperative bracing, which outcomes were very quite horrifying. Hibbs’ fusion operation had become a realistic treatment option to halt the progression of deformity in the early 20th century. Harrington’s introduction of the internal fixation device to treat paralytic scoliosis in 1960’s started revolution on deformity correction surgery. Luque developed a segmental spinal using sublaminar wiring technique in 1976 and Cotrel developed Cotrel-Dubousset (CD) instrumentation, which was a posterior segmental instrumentation system that used pedicle and laminar hooks on either thoracic or lumbar spine and pedicle screws on the lumbar spine.

Stabilization of the Atlantoaxial Joint With C1-C3 Lateral Mass Screw Constructs: Biomechanical Comparison With Standard Technique

Anatomically and biomechanically, the atlantoaxial joint is unique compared with the remainder of the cervical spine. To assess the in vitro stability provided by 2 C2 screw sparing techniques in a destabilized model of the atlantoaxial joint and compare with the gold standard system. The 3-dimensional intervertebral motion of 7 human cadaveric cervical spine specimens was recorded stereophotogrammetrically while applying nonconstraining, nondestructive pure moments during flexion-extension, left and right axial rotation, and left and right lateral bending. Each specimen was tested in the intact state, followed by destabilization (odontoidectomy) and fixation as follows: (1) C1 and C3 lateral mass screws rods with sublaminar wiring of C2 (LC1-C3 + SW), (2) C1 and C3 lateral mass screws rods with a cross-link in the C1-2 interlaminar space (LC1-C3 + CL), (3) C1 and C3 lateral mass screw rods alone (negative control), and (4) C1 lateral mass and C2 pedicle screws rods augmented with C1-2 interspinous wire and graft (LC1-PC2, control group). Compared with the intact spine, each instrumented state significantly stabilized range of motion and lax zone at C1-2 (P < .001, 1-way repeated-measures analysis of variance). LC1-C3 + SW was equivalent to LC1-PC2 during flexion and lateral bending and superior to LC1-C3 + CL during lateral bending, while LC1-C3 + CL was equivalent to LC1-PC2 only during flexion. In all other comparisons, LC1-PC2 was superior to both techniques. From a biomechanical perspective, both C2 screw sparing techniques provided sufficient stability to be regarded as an alternative for C1-2 fixation. However, because normal motion across C2-3 is sacrificed, these constructs should be used in patients with unfavorable anatomy for standard fixations.

Transarticular screw fixation for atlantoaxial instability - modified Magerl's technique in 38 patients.

BackgroundSymptomatic atlantoaxial instability needs stabilization of the atlantoaxial joint. Among the various techniques described in literature for the fixation of atlantoaxial joint, Magerl's technique of transarticular screw fixation remains the gold standard. Traditionally this technique combines placement of transarticular screws and posterior wiring construct. The aim of this study is to evaluate clinical and radiological outcomes in subjects of atlantoaxial instability who were operated using transarticular screws and iliac crest bone graft, without the use of sublaminar wiring (a modification of Magerl's technique).MethodsWe evaluated retrospectively 38 subjects with atlantoaxial instability who were operated at our institute using transarticular screw fixation. The subjects were followed up for pain, fusion rates, neurological status and radiographic outcomes. Final outcome was graded both subjectively and objectively, using the scoring system given by Grob et al.ResultsInstability in 34 subjects was secondary to trauma, in 3 due to rheumatoid arthritis and 1 had tuberculosis. Neurological deficit was present in 17 subjects. Most common presenting symptom was neck pain, present in 35 of the 38 subjects.Postoperatively residual neck and occipital pain was present in 8 subjects. Neurological deficit persisted in only 7 subjects. Vertebral artery injury was seen in 3 subjects. None of these subjects had any sign of neurological deficit or vertebral insufficiency. Three cases had nonunion. At the latest follow up, subjectively, 24 subjects had good result, 6 had fair and 8 had bad result. On objective grading, 24 had good result, 11 had fair and 3 had bad result. The mean follow up duration was 41 months.ConclusionsTransarticular screw fixation is an excellent technique for fusion of the atlantoaxial complex. It provides highest fusion rates, and is particularly important in subjects at risk for nonunion. Omitting the posterior wiring construct that has been used along with the bone graft in the traditional Magerl' s technique achieves equally good fusion rates and is an important modification, thereby avoiding the complications of sublaminar wire passage.

Posterior Kyphectomy for Myelomeningocele With Anterior Placement of Fixation: A Retrospective Review

Kyphosis in myelomeningocele is a rare and difficult problem. Many strategies have been used with no single procedure universally agreed on. Techniques involving anterior and posterior fixation may provide better fusion. We describe a novel procedure for anteroposterior kyphectomy in patients with myelomeningocele. Apical posterior kyphectomy is followed by the insertion of two rods distally into the vertebral bodies and sacrum. Sublaminar wires are placed superiorly and the kyphosis is reduced by sequential tightening. We determined kyphosis correction and intraoperative blood loss for this new procedure. We retrospectively reviewed 22 patients (average age, 7.6 years [range, 2-17 years]) who underwent apical kyphectomy from 1982 to 2008. Charts were examined and radiographs measured preoperatively, immediately postoperatively, and at final followup. Followup averaged 6.4 years (range, 0-14 years) with 19 patients having at least 2 years of followup. Kyphosis decreased from a mean of 123° (range, 79°-163°) preoperatively to 40° (range, 13°-92°) immediately postoperatively and was a mean of 60° (range, 14°-126°) at final followup. Operating time was 248 minutes (range, 180-345 minutes), estimated blood loss was 765 mL (range, 140-2100 mL), and length of stay was 14 days (range, 1-57 days). Ten of the 22 patients had complications with eight requiring reoperation. This anteroposterior kyphectomy provided a high level of kyphosis correction, which was largely maintained over the study period. Blood loss, surgical time, and complication rates were acceptable as compared with other techniques reported in the literature.

Evaluation of pullout strength and failure mechanism of posterior instrumentation in normal and osteopenic thoracic vertebrae

There is limited data on the pullout strength of spinal fixation devices in the thoracic spine among individuals with different bone quality. An in vitro biomechanical study on the thoracic spine was performed to compare the pullout strength and the mechanism of failure of 4 posterior fixation thoracic constructs in relation to bone mineral density (BMD). A total of 80 vertebrae from 11 fresh-frozen thoracic spines (T2-12) were used. Based on the results from peripheral quantitative CT, specimens were divided into 2 groups (normal and osteopenic) according to their BMD. They were then randomly assigned to 1 of 4 different instrumentation systems (sublaminar wires, pedicle screws, lamina claw hooks, or pedicle screws with wires). The construct was completed with 2 titanium rods and 2 transverse connectors, creating a stable frame. The pullout force to failure perpendicular to the rods as well as the pattern of fixation failure was recorded. Mean pullout force in the osteopenic Group A (36 vertebrae) was 473.2 ± 179.2 N and in the normal BMD Group B (44 vertebrae) was 1414.5 ± 554.8 N. In Group A, no significant difference in pullout strength was encountered among the different implants (p = 0.96). In Group B, the hook system failed because of dislocation with significantly less force than the other 3 constructs (931.9 ± 345.1 N vs an average of 1538.6 ± 532.7 N; p = 0.02). In the osteopenic group, larger screws demonstrated greater resistance to pullout (p = 0.011). The most common failure mechanism in both groups was through pedicle base fracture. Bone quality is an important factor that influences stability of posterior thoracic implants. Fixation strength in the osteopenic group was one-fourth of the value measured in vertebrae with good bone quality, irrespective of the instrumentation used. However, in normal bone quality vertebrae, the lamina hook claw system dislocated with significantly less force when compared with other spinal implants. Further studies are needed to investigate the impact of different transpedicular screw designs on the pullout strength in normal and osteopenic thoracic spines.

Does Wide Posterior Multiple Level Release Improve the Correction of Adolescent Idiopathic Scoliosis Curves?

Retrospective matched cohort study. To compare results of posterior correction and fusion with a hybrid construct using a standard posterior release (SPR) versus adding a wide posterior release (WPR), in adolescent idiopathic scoliosis (AIS) treated at a single institution, with a minimum 2-year follow-up. Although the importance of posterior release has been enhanced for the correction of AIS, there have been no reports comparing correction results when posterior wide release (excision of all posterior ligaments and bilateral extended facetectomy at multiple levels) is used. A retrospective study of 46 patients with AIS was performed. Posterior-only hybrid instrumentation with sublaminar wires was included. SPR group consisted of 25 patients and WPR group consisted of 21 patients. There was no difference in sex, age, type of curve, number of instrumented levels, length of surgery, and preoperative main curve Cobb (SPR: 60±10 degrees WPR: 59±8 degrees). In the WPR group, the amount of main curve correction obtained was significantly greater (SPR: 57% vs. WPR: 68.6%) P<0.001, and maintained at final follow-up (SPR: 51.6% vs. WPR: 61.8%) P<0.05. Preoperative and postoperative proximal thoracic and lumbar secondary curves were similar in both the groups. T5-T12 preoperative kyphosis were (SPR: 22.2±11 degrees vs. WPR: 19±11 degrees) the degrees corrected in postoperation (SPR: +1.2±6 degrees vs. WPR: -0.9±9 degrees) and at final follow-up (SPR: +1.6±8 degrees vs. WPR: -0.8±11 degrees), and were not statistically different P>0.05. Minor complications were similar in both groups and no major complications were found. Posterior wide release at multiple levels improves coronal main curve correction in patients with AIS, without an increase in the incidence of complications. Furthermore, it improves fusion surface and makes insertion of sublaminar wires easier.

Management of Acute Cervical Compression Fractures in Two Patients With Osteogenesis Imperfecta

We report 2 cases of acute cervical compression fracture in patients with osteogenesis imperfecta (OI). In case 1, a 15-year-old girl with an acute C6 compression fracture and additional fractures of the posterior elements underwent a C6 corpectomy and instrumented posterior fusion. In case 2, a 46-year-old man with a C7 compression fracture was managed nonoperatively. To illustrate a subset of possible acute subaxial cervical fractures in OI patients and to describe the feasibility of performing a combined anterior/posterior cervical decompression and fusion in an OI patient. OI is a rare genetic collagen disorder that is characterized by bone fragility and ligamentous laxity. Spinal complications associated with this disease included scoliosis, thoracolumbar compression fractures, and other spinal fractures, cervical spondyloptosis, and basilar invagination. There is limited literature that addresses the management of acute cervical spine fractures in OI patients. In case 1, the patient was initially treated with a Minerva brace. Nonoperative management was abandoned when a progressive kyphotic deformity developed. A C6 corpectomy and placement of a fibular strut allograft was followed by a C4-C7 posterior fusion with sublaminar wiring and rods. In case 2, the patient was managed nonoperatively with a rigid cervical collar alone. In case 1, the patient made a prompt recovery, and on 12-month follow-up has maintained alignment. In case 2, the patient maintained normal alignment without need for surgical intervention. A combined anterior/posterior decompression and fusion of the subaxial cervical spine is feasible in the fragile OI population. Moreover, certain isolated compression fractures of the subaxial cervical spine in this same patient population may be managed nonoperatively.

Treatment of scoliosis in patients affected with Prader-Willi syndrome using various techniques

BackgroundThe incidence of spinal deformity in children with Prader-Willi syndrome (PWS) is high, with 86% of these patients found to have a significant structural scoliosis; however, there are very few case reports describing surgical treatment for this deformity.MethodsThe authors reviewed a case series consisting of 6 patients who underwent spine surgery for scoliosis. Children's mean age at index surgery was 12 years and 10 months (range, 10 to 15 yrs). Clinical evaluation revealed the typical phenotypic features of the PWS in all of the patients; 4 subjects had a karyotype confirmation of PWS. Major structural curves showed preoperative mean Cobb angles of 80.8° (range, 65° to 96°). Hybrid instrumentation with sublaminar wires, hooks and screws was used in the first 2 patients, while the remaining 4 were treated with titanium pedicle screw constructs.ResultsThe mean clinical and radiological follow-up was 3 years and 10 months (range, 2 years to 9 years). Major complication rate was 50%. One patient who developed a major intraoperative complication (paraparesis) prevented spinal fusion to be obtained: the neurologic deficit resolved completely after instrumentation removal. Solid arthrodesis and deformity correction in both coronal and sagittal plane was, however, achieved in the other 5 cases and no significant curve progression was observed at follow-up. Another major short-term complication was encountered 3 months after surgery in a patient who experienced the detachment of a distally located rod and required correction through revision surgery and caudal extension by one level. Cervico-thoracic kyphosis was seen in 1 patient who did not require revision surgery.ConclusionsSpine reconstructive surgery in patients with PWS is rare and highly demanding.The best method of reconstruction is posterior multilevel pedicle screw fixation. Moreover, even with modern techniques, the risk of complications is still high. These new techniques, however, have shown to improve the postoperative course by allowing for immediate mobilization without any brace or cast. The use of the growing rod techniques, requiring repeated surgeries, should be carefully evaluated in each single case.

Surgical correction of severe dystrophic neurofibromatosis scoliosis: an experience of 32 cases

The surgical management of severe rigid dystrophic neurofibromatosis curves is a demanding procedure with uncertain results. Several difficulties are present in such patients including a poor bone stock, sharp angulation of these dystrophic curves and dural thinning or ectasia. The aim of this work was to review the clinical and radiographic outcomes of three-dimensional correction of severe rigid neurofibromatosis curves analyzing its efficacy, safety and possible complications. Thirty-two patients were followed up for an average of 6.5 years (range 3-9 years). The average age at surgery was 14 years (range 11-19 years). All patients had typical dystrophic curves, and the apex of the deformity was thoracic (n = 13), thoracolumbar (n = 14) and lumbar (n = 5). All patients had a two-staged procedure; an anterior release followed latter by posterior hybrid instrumentation augmented by sublaminar wires. Two wires were usually placed immediately below the proximal anchor, and several sublaminar wires were always passed at the apex of the deformity. There were a total of 142 wires with an average of 6.5 wires/patient (range 5-8 wires). The mean preoperative Cobb angle of the scoliotic curve was 102.2 degrees (range 71 degrees-114 degrees) corrected to an average of 39 degrees (range 16 degrees-49 degrees), and the loss of correction had an average of 4 degrees. The mean preoperative sagittal plane deformity was 49 degrees corrected by an average of 61%, and rotation was corrected by an average of 34%. There were no dural tears during passage of the sublaminar wires, no implant-related complications and no permanent neurologic deficits. The use of extensive and vigorous anterior release with posterior hybrid instrumentation has proved useful and effective in the treatment of these severe deformities; sublaminar wires allow safe gradual correction and even distribution of forces over multiple anchor points improving the correction achieved and decreasing implant-related complications.

Isolated osteoradionecrosis of the dens mimicking metastasis of nasopharyngeal carcinoma after radiotherapy

Nasopharyngeal carcinoma (NPC) is common in southern China, and radiotherapy remains the mainstay of treatment. A rare late complication of this treatment is the development of osteoradionecrosis (ORN), which seldom involves the cervical spine. We describe a 47-year-old female with undifferentiated carcinoma of the nasopharynx, stage II (T2N0M0), who had undergone radiotherapy 51 months prior, and complained of a twitching headache on neck flexion/extension. Imaging studies, including MRI and 18-fluoro-2-deoxyglucose positron emission tomography scan, suggested the diagnosis of cervical spinal metastasis. However, plasma Epstein-Barr virus DNA was undetectable, favoring absence of tumor recurrence. The patient underwent atlantoaxial sublaminar wiring for an unstable spine and a subsequent transoral biopsy, the histopathologic diagnosis of ORN. The postoperative clinical course was uneventful and follow-up MRI, 2 years later, revealed gradual resolution of the lesion. To our knowledge this is the first report of an isolated ORN lesion of the dens confirmed surgically in a patient with a history of previously treated NPC, a lesion at the cervical spine, and inconclusive imaging and biological marker results. We recommend that ORN be suspected until proven otherwise in a previously irradiated patient.

Complications of the Luque–Galveston scoliosis correction technique in paediatric cerebral palsy

Severe scoliosis is a very frequent condition in cerebral palsy children (CP). It is surgically managed, with unit rod instrumentation being the gold standard in English-speaking countries. The purpose of this work was to report on a small, homogeneous series of non-ambulatory, quadriplegic, spastic patients treated by the Luque-Galveston technique in Strasbourg, France. We present the radiographic outcome of the technique along with a full description of any post-operative complications encountered. Twenty-eight children were operated on according to the Luque-Galveston technique between January 1997 and January 2006. This instrumentation, with fusion, included the whole spine from the sacrum to level T2. All procedures were performed as a one-stage posterior arthrodesis. The spinal deformities were single thoraco-lumbar curvatures, except in one patient. Both curve magnitude and pelvic obliquity were measured by X-ray pre-operatively, post-operatively and after longest follow-up (over 24 months). Our study focused on the rate of complications of this treatment. Only 16 patients out of 28 were tracked since the remaining 12 were lost to follow-up. Mean curve magnitude was corrected from 80 degrees to 34.8 degrees (mean correction, 56.5%), and pelvic obliquity, from 20.9 degrees to 4.2 degrees (mean correction, 79.6%). Loss of correction at average 3.46-year follow-up was 3.9 degrees of curve magnitude and 2.7 degrees of pelvic obliquity. Mean operating time was 301.5 minutes, and average blood loss was 861.9 ml. Patients were discharged from hospital after an average 19.5-day stay, including mean 8.4-day intensive care unit stay. A single major complication, monocular blindness, occurred during the procedure, probably resulting from air embolism. Post-operative complications (totaling 57.1% of our 28 patients) were: one death, three pneumothoraxes, six segmental atelectasias, seven pneumonias and one superficial wound infection. Late-onset complications (totaling 56.2% of our 16 patients at latest follow-up) were: seven broken sublaminar wires, one iliac perforation by the rod, one skin irritation from extreme malnutrition needing hardware removal, and three superficial sacral decubitus ulcers. Our correction rate in children affected by CP and manifesting severe scoliosis is similar to that reported in the literature by different surgical teams. Moreover, we did not observe any deep wound infection, haematoma, septicaemia, neurological and digestive complications. Late-onset complications mainly involved asymptomatic sublaminar wire breakage at the two uppermost levels, but no major complication was due to hardware failure, and vertebral fracture did not occur. There was no need for re-intervention because of the hardware, except for one case in which extreme malnutrition provoked skin conflict with the rod. We encountered 10 "windshield wiper" effects in the iliac bone, but we believe they cannot be considered as complications since they seemed to disappear after fusion was fully obtained. Last but not least, unit rod instrumentation is not very expensive compared to more modern techniques. Correction of scoliosis and pelvic obliquity, attributed to CP in non-ambulatory children, by the Luque-Galveston technique is both an effective and safe choice in such an indication. Moreover, it is far less expensive than most other techniques, an aspect which should be taken into consideration. Level IV retrospective therapeutic study.

Instable cervical spine injury in a toddler: technical note

Instable upper cervical spine injuries (CSI) in very young children are rare and consecutively only few data on the treatment and operative approaches exist in the literature. Hence, we suggest an operative strategy in the case of a 15-month-old infant treated for an instable CSI at the level of C2/3 at our department. Detailed steps of the operation with special consideration to the challenging anatomy of the immature spine are presented. A toddler suffered a CSI without neurological deficits after a stair fall. Computer tomography (CT) and magnetic resonance imaging (MRI) of the cervical spine revealed an instable luxation fracture of C2/3. As repositioning in the halo vest immobilization failed, surgical fusion was indicated. Via a posterior midline approach, the lamina of C2 and C3 was conflated in a modified sublaminar wiring technique using non-resorbable sutures, sparing the ossification zones of the vertebral arches. Postoperative immobilization in a halo vest facilitated bony fusion of the laminae at C2/3 without lordotic displacement of the cervical spine. We consider the instable CSI of the immature cervical in the very young a challenging situation for every treating physician. The particular features of the growing spine require special attention to avoid damage to the growth centers of the vertebrae. To our knowledge, this is the first technical report giving detailed information of an operative approach to the severely injured immature cervical spine and postoperative management.

Spinal loop rectangle and sub laminar wiring as a technique for scoliosis correction

Background:Most literature popularizes the efficacy of third generation instrumentation in the surgical correction of spinal deformities. A cheap and effective scoliotic deformity correction method is reviewed in this article. The aim of this study is to evaluate the efficacy of spinal loop rectangle and sub laminar wires as a modality for spinal deformity correction and its co-relation with patients' satisfaction and clinical outcome.Material and Methods:Thirty six patients of scoliotic spinal deformities with various etiologies (congenital-4, idiopathic- 25, neurofibromatosis-3, neuromuscular-2 and ‘syndromic’-3) with ages ranging from 8 to 23 years underwent corrective posterior spinal arthrodesis with stainless steel Hartshill loop rectangle and sublaminar wires. Clinicoradiological evaluation was done at an average follow-up of 6 ½ years (min-2 ½, years). Along with clinicoradiological outcome, patient satisfaction (as per the SRS 24), was accounted.Results:Average preoperative Cobb's angle were 73.25° in the entire group and 66.48° in the idiopathic group. Average percentage correction was 64.34% in the entire group and the (average degree of correction was 47.13). In the idiopathic group, the respective values were 69.19% and 46°. Loss of correction in the whole group was 2.2° at two year follow up. Sagittal profiles, truncal balance were well corrected too; minimal complications were seen. Patient satisfaction results were encouraging in 36 patients as per – SRS24). About 80.2% patients were ready to undergo the same surgery if required. (SRS24).Conclusion:Segmental spinal fixation with locally made spinal loop rectangle and sublaminar wires is comparable as a modality to correct scoliotic spinal deformities.

Hybrid Constructs for Tridimensional Correction of the Thoracic Spine in Adolescent Idiopathic Scoliosis

Retrospective study of prospectively collected data. Compare Universal Clamps (UCs) and hooks for the thoracic correction of adolescent idiopathic scoliosis (AIS). In scoliosis surgery, sagittal correction is as important as frontal correction due to the risk of junctional kyphosis. Compared to all-screw constructs, hybrid constructs with lumbar pedicle screws and thoracic hooks or sublaminar wires have been shown to achieve similar coronal correction while providing superior postoperative thoracic kyphosis. The authors used a novel sublaminar thoracic implant, the UC with improvements over sublaminar wires. Hybrid constructs using thoracic UCs were compared to those with thoracic hooks. This series involved 150 patients treated for AIS with hybrid constructs. A total of 75 consecutive patients operated from 2001 to 2003, who had thoracic hooks with in situ contouring, distraction, and compression (Group 1), were compared to 75 consecutive patients operated from 2004 to 2006, who had thoracic UCs with posteromedial translation (Group 2). All had intraoperative somatosensory/motor-evoked potential monitoring and at least 2-years follow-up. Except for follow-up (longer in Group 1), the 2 groups were similar before surgery. The UCs achieved better thoracic coronal correction (P < 0.001), Cincinnati index (P < 0.001), kyphosis (P = 0.02), and apical rotation (P < 0.001). In normokyphotic or hypokyphotic patients, the UC corrected thoracic kyphosis by 11.2 degrees (55%) versus 0.4 degrees (2%) achieved by hooks (P < 0.0001). These differences were stable at last follow-up. There were no intraoperative complications or changes in somatosensory/motor-evoked potentials. UC reduced operative time by 20% (60 minutes; P < 0.001) and blood loss by 23% (250 mL; P < 0.001). Although both of these hybrid constructs efficaciously corrected the coronal and axial deformities in AIS, the results of the UC technique were superior to those achieved with hooks in all 3 planes, especially the sagittal plane. Moreover, the UC technique is straightforward and safe, reducing both operative duration and blood loss.

Biomechanical Analysis Comparing Three C1–C2 Transarticular Screw Salvaging Fixation Techniques

This is an in vitro biomechanical study. To compare the biomechanical stability of the 3 C1-C2 transarticular screw salvaging fixation techniques. Stabilization of the atlantoaxial complex is a challenging procedure because of its complicated anatomy. Many posterior stabilization techniques of the atlantoaxial complex have been developed with C1-C2 transarticular screw fixation been the current gold standard. The drawback of using the transarticular screws is that it has a potential risk of vertebral artery injury due to a high riding transverse foramen of C2 vertebra, and screw malposition. In such cases, it is not recommended to proceed with inserting the contralateral transarticular screw and the surgeon should find an alternative to fix the contralateral side. Many studies are available comparing different atlantoaxial stabilization techniques, but none of them compared the techniques to fix the contralateral side while using the transarticular screw on one side. The current options are C1 lateral mass screw and short C2 pedicle screw or C1 lateral mass screw and C2 intralaminar screw, or C1-C2 sublaminar wire. Nine fresh human cervical spines with intact ligaments (C0-C4) were subjected to pure moments in the 6 loading directions. The resulting spatial orientations of the vertebrae were recorded using an Optotrak 3-dimensional Motion Measurement System. Measurements were made sequentially for the intact spine after creating type II odontoid fracture and after stabilization with unilateral transarticular screw placement across C1-C2 (TS) supplemented with 1 of the 3 transarticular salvaging techniques on the contralateral side; C1 lateral mass screw and C2 pedicle screw (TS+C1LMS+C2PS), C1 lateral mass and C2 intralaminar screw (TS+C1LMS+C2ILS), or sublaminar wire (TS + wire). The data indicated that all the 3 stabilization techniques significantly decreased motion when compared to intact in all the loading cases (left/right lateral bending, left/right axial rotation, flexion) except extension. All the 3 instrumented specimens were equally stable in extension/flexion and lateral bending modes. TS+C1LMS+C2PS was equivalent to TS+C1LMS+C2ILS (P > 0.05) and superior to TS + wire in axial rotation (P < 0.05). Also, TS+C1LMS+C2ILS was superior to TS + wire in axial rotation (P < 0.05). Fixation of atlantoaxial complex using unilateral transarticular screw supplemented with contralateral C1 lateral mass and C2 intralaminar screws is biomechanically equivalent to C1 lateral mass and C2 pedicle screws and both are biomechanically superior to C1-C2 sublaminar wire in axial rotation.

Use of the Universal Clamp for deformity correction and as an adjunct to fusion: Preliminary results in scoliosis

Evaluation of a novel instrumentation device for adolescent idiopathic scoliosis. A new osteosynthesis implant (Universal Clamp) primarily consisting of a sublaminar band and titanium clamp was prospectively studied in 32 patients (average age, 15years) with a major thoracic curve. The Universal Clamp was used without anterior release to reduce and maintain correction of the thoracic curve, which improved from 55.1° preoperatively to 14.5° at 3months without neurological complication or loss of kyphosis. This implant distributes stress over a larger area of the laminar cortex than sublaminar wires, patently reducing the risk of laminar fracture for equivalent reduction forces, and permits progressive reduction at several apical levels simultaneously.

Unilateral Atlantoaxial Transpedicular Screw and Rod/Plate Fixation With Sublaminar Polyethylene Cable Fixation

This report presents 2 of the cases of primary posterior unilateral atlantoaxial transpedicular screw and rod/plate fixation supplemented by a polyethylene cable as sublaminar wiring for the treatment of a patient with atlantoaxial subluxation. The patients had a unilateral high-riding vertebral artery at the axis, and a unilateral screw and rod/plate fixation with sublaminar fixation was performed to provide more rigid stabilization at the atlantoaxial junction. One patient with a delayed nonreducible odontoid fracture had a good outcome with a complete reduction and posterior fusion. The other elderly patient achieved a sufficient union at the fracture site of the odontoid process; however, resorption of the interlaminar grafting bone was observed. The stability of the unilateral transpedicular screw and rod/plate fixation with sublaminar polyethylene cable fixation might therefore be insufficient to obtain the fusion of the grafted bone in an osteoporotic elderly patient. Another procedure such as a laminar screw procedure should thus be considered for such a patient.