Sublaminar Wires Research Articles

Safety and efficacy of spinal loop rectangle and sublaminar wires for osteoporotic vertebral compression fracture fixation.

Background:Natural history of osteoporotic vertebral compression fractures (OVCFs), that is, collapse, loads the rigid pedicle screw rod construct in the absence of anterior column reconstruction, often leading to implant back outs. Semi rigid spinal loop rectangle and sublaminar wire construct allows controlled axial collapse and does not require anterior column reconstruction.Materials and Methods:This is a retrospective study of 50 consecutive patients of OVCFs. The immediate and final follow-up safety (neurologic deficit, implant failure/back out, revision surgeries, and infection) and efficacy (visual analog scale [VAS] score, axial collapse of the fracture, fracture union and retaining, and the attempted segmental deformity correction) parameters were compared to describe the utility of spinal loop rectangle and sublaminar wiring as a novel, low cost modality of spinal instrumentation for treating OVCFs.Results:All the twelve patients with Frankel grade D neurologic deficit improved to Frankel grade E and six patients (out of 8) with Frankel grade C improved to Frankel grade E (and remaining two patients improved to Frankel grade D), following surgery. The average preoperative VAS score of 8.98 (ranging from 5 to 10) improved to 2.76 (ranging from 1 to 10) at final follow-up. Controlled collapse of anterior column, union of OVCF nonunion, and retaining of attempted deformity correction by sublaminar wire anchors cephalad and caudal to the transpedicular decompression was seen in each patient at the final follow-up.Conclusion:Spinal loop rectangle and sublaminar wiring construct are viable alternative options for stabilizing OVCFs.

The Versatile Approach: A Novel Single Incision Combined with Anterior and Posterior Approaches for Decompression and Instrumented Fusion to Treat Tuberculosis of the Thoracic Spine.

Study DesignRetrospective case series.PurposeTo describe a novel single incision that combines anterior and posterior approaches for decompression and instrumented fusion to treat tuberculosis of the thoracic spine and study the neurological and radiological outcomes.Overview of LiteratureTuberculosis of the spine remains a major health issue in many developing countries. The options for treating tuberculosis of the thoracic spine include the anterior, posterior, and combined approaches, each with its advantages and disadvantages.MethodsTotally, 143 patients with tuberculosis of the thoracic spine were surgically treated using the “Versatile approach”. Posterior fixation was performed using sublaminar wires and a Hartshill rectangle in all patients. Anterior reconstruction was accomplished using bone graft harvested from autologous rib, iliac crest, or fibula.ResultsThe study included 45 males and 98 females, with a mean age of 33.18±18.65 years (range, 3–82 years) and a mean follow-up of 60.23±24.56 months (range, 18–156 months). Kyphosis improved from a mean value of 24.02 preoperatively to 10.25 postoperatively. A preoperative neurological deficit was observed in 131 patients, with 130 patients regaining ambulatory power. No patient had deterioration of neurological status following surgery. Fusion was achieved in all cases. The visual analogscale score improved from an average score of 7.02 preoperatively to 1.51 at final follow-up. Eight patients had superficial macerations, which healed spontaneously. One patient had buckling of the anterior graft, and one patient had implant breakage following road traffic accident.ConclusionsThe “Versatile approach” is an effective, single-stage, single-incision method that combines anterior and posterior approaches for the surgically treating tuberculosis of the thoracic spine. It offers the advantage of direct visualization for decompression and reconstruction of the anterior and posterior vertebral columns, thus providing an excellent, long-lasting clinical outcome.

Complications of spinal fusion with sublaminar wire

Complications of spinal fusion with sublaminar wire

Usefulness of Sacral Sublaminar Wire for Low Transverse Sacral Fractures: Two Cases’ Report

Low transverse sacral fractures are rare, with only two published reports regarding their surgery. The complication associated with surgery for sacral fractures is the prominence of implants. In addition, screw fixation below S3 is impractical. We performed posterior sacral fixation using S2 alar iliac (S2AI) screws and sacral sublaminar wires for low transverse sacral fractures. Case 1 was 65-year-old male with an S2-3 transverse sacral fracture. We performed laminectomy (S2-3) and passed ultrahigh molecular weight polyethylene (UHMWPE) cables from laminectomy area to the third posterior sacral foramina. We inserted S2AI screws and connected rods. We also tightened the UHMWPE cables. The implants did not protrude into skin. One year after surgery, the sacral fracture healed without any displacement. Case 2 was a 42-year-old female with an S2 transverse sacral fracture. We performed laminectomy (S1–3) and passed UHMWPE cables from laminectomy area to the third and fourth posterior sacral foramina. We inserted S1 pedicular screws and S2AI screws and connected rods. We also tightened UHMWPE cables. The implants did not protrude into skin. One year after surgery, the sacral fracture healed without any displacement. We consider sacral sublaminar wires to be useful bone anchors in lower sacrum.

Interventions for osteoporosis in patients with degenerative scoliosis

Osteoporosis is a disorder of bone metabolism primarily affecting elderly individuals in the United States. Structurally, there is a decrease in the quantity of bone which can lead to fracture and degenerative changes in the spine. These changes lead to altered mechanics, deformity, and diminished quality of life. According to estimates, the aging population will further intensify the burden of disease in the upcoming decades and rates of spine surgery are increasing in this population. Osteoporosis presents a unique set of challenges for instrumentation and correction of spinal deformity. Several medical therapies are available to improve bone quality. These include calcium and vitamin D supplementation to increase the raw materials for bone formation in deficient individuals. Additionally, medications like bisphosphonates, denosumab, and recombinant PTH (teriparatide) directly alter the biochemical process regulating resorportion and bone formation. While initial studies have generally shown positive effects of these therapies on bone quantity, their effectiveness in spine surgery and in improving fusion rates is inconsistent. As a result, there is no consensus on preoperative and postoperative protocols. Intraoperative interventions aim at improving the durability of fixation in osteoporotic bone and preventing catastrophic complications. Prime methods of attaining durable fixation are by increasing the amount of points of fixation often by creating longer constructs and extending to the pelvis. Additionally, augmenting pedicle screw fixation with sublaminar wires and hooks has shown improved fixation. Regarding individual pedicle screws, techniques like cementing pedicle screws, increasing insertional torque, and attaining bicortical fixation have significantly improved the pullout strength. Methods of preventing proximal junctional kyphosis include adding hooks at the most proximal level and limiting construct stiffness proximally. Osteoporotic bone presents many challenges when trying to manage deformity. Adequate preoperative planning includes assessing risk factors, taking measures to improve BMD with or without the addition of medical therapies. Intraoperatively, technical considerations aim to improve bone/implant interface as well as increase the number of fixation points.

UHMWPE Sublaminar Wires in Posterior Spinal Instrumentation: Stability and Biocompatibility Assessment in an Ovine Pilot Study.

An animal study. To explore ultra-high molecular weight polyethylene (UHMWPE) sublaminar wires in spinal surgery and to assess stability and biocompatibility of the UHMWPE instrumentation in an ovine model. Sublaminar wiring is a well-established technique in segmental scoliosis surgery. However, during introduction and/or removal of the metal sublaminar wires, neurological problems can occur. Abrasion after cutting metal wires for removal can lead to damage to the dural sac. Sublaminar wires have to withhold large forces and breakage of the wires can occur. Different types of sublaminar wires have been developed to address these problems. UHMWPE sublaminar wires can potentially substitute currently used metal sublaminar metal wires. In vivo testing and biocompatibility analysis of UHMWPE wires are recommended before clinical use in spinal surgery. In 6 immature sheep, pedicle screws were instrumented at lumbar level L4 and attached with titanium rods to 4 thoracolumbar vertebrae using 3- and 5-mm-wide UHMWPE sublaminar wiring constructions in 5 animals. Titanium sublaminar wires were applied in 1 animal to function as a control subject. After a follow-up period of 16 weeks, the animals were sacrificed and the spines were isolated. Radiographs and computed tomography (CT) scans were made to assess stability of the instrumentation. The vertebrae were dissected for macroscopic and histologic evaluation. None of the wires had loosened and the instrumentation remained stable. CT scans and radiographs showed no signs of failure of the instrumentation and no neurological complications occurred. Although several bony bridges were seen on CT, growth was observed at the operated levels. Biocompatibility was assessed by macroscopical and histologic analysis, showing no signs of dural or epidural inflammation. This pilot animal study shows that UHMWPE sublaminar wiring is a safe technique. The UHMWPE wires are biocompatible and provide sufficient stability in spinal instrumentation. Heterotopic ossification because of periost reactions in the ovine spine led to some restrictions in this study.

Misdirection- What The Eyes See and The Ears Hear, The Mind Believes- A Retrospective Study of Misdirected Pedicle Screw Fixations in Thoracolumbar Spine

Transpedicular stabilization has become an established method for instrumentation of the thoracic and lumbar spine because of its immediate rigidity, better coronal and sagittal correction and shorter fusion length when compared to the other instrumentation techniques. Pedicle screw insertion resulting in neurologic deficit is rare, but may be due to faulty placement of the screw, with perforation of the cortex and impingement on adjacent neural structures. Despite improvements in the design of the instruments and attention to insertion techniques, cortical perforation does occur. Because many transgressions are asymptomatic, the true incidence is not known. Roy-Camille et al report in their experience 10% of screws were not completely in the pedicle. A retrospective study was done to determine the incidence of screw misplacement and complications in 120 transpedicular screws (30 patients) in the thoracolumbar spine with conventional open technique and intraoperative fluoroscopy. Outcome measures were: Accuracy of screw placement was evaluated by postoperative CT scan. Screw position was classified as 1.correct when the screw was completely surrounded by the pedicle cortex, 2. cortical breach and as 3. frank penetration when the screw was outside the pedicular boundaries. Frank penetration was further subdivided as grade A (up to 2.0 mm), grade B(2.1-4 mm), and grade C(> 4 mm).Results- In our study we found out that only 56 screws were in the category of correct, while a total of 40 pedicle screws had Frank penetration, mostly medially(followed by laterally and anteriorly) with a grade B penetration (followed by grade A and grade C) with 8 complications attributable to this misdirections, of which, 4 each had medial and lateral breech, all of which thankfully completely resolved with time at subsequent follow up. The use of pedicle screw instrumentation was described by Boucher in 1950s and was popularized by Roy-Camille et al in 1960s. The initial use of pedicle screws began in the lumbar spine and as surgeons became more comfortable with the complex anatomy required for accurate screw placement, they evolved the use of pedicle instrumentation in thoracolumbar and thoracic spine.Transpedicular screw fixation has many advantages over other spinal instrumentations such as Harrington rod fixation, Luque's instrumentation, etc., in various pathologies. Pedicle screws also prevent the need to place instrumentation within the spinal canal like sublaminar wiring, which creates the risk of neurological injury. Transpedicular stabilization has become an established method for instrumentation of the thoracic and lumbar spine because of its immediate rigidity, better coronal and sagittal correction and shorter fusion length when compared to the other instrumentation techniques. Comparing pedicle screws, wires, and hooks, the highest incidence of symptomatic impingement occurs with pedicle screws, with nerve root injury or irritation occurring in a reported 3.2% of cases. Pedicle screw insertion resulting in neurologic deficit is rare, but may be due to faulty placement of the screw, with perforation of the cortex and impingement on adjacent neural structures. Despite improvements in the design of the instruments and attention to insertion techniques, cortical perforation does occur. Because many transgressions are asymptomatic, the true incidence is not known. Roy- Camille et al report in their experience 10% of screws were not completely in the pedicle. Ideally, the pedicle screw is completely contained within the pedicle, and the spinal canal is not violated. Pedicle screws that violate the pedicle cortex increase the risk of neurologic injury; however, minor violations of the cortex are not uncommon and may be asymptomatic. In these cases, the screw position may be acceptable. Ultimately, patient symptomatology is probably the most important factor in determining acceptable positioning of the screw.

The effect of sublaminar wires on the rib hump deformity during scoliosis correction manoeuvres.

During thoracic curve correction, the tightening of the sublaminar wires through concavity creates a medial and a dorsal translation of the spine. However, little is known about the effect of the sublaminar wires on the axial plane. This is prospective case series analysis of 30 consecutive surgical patients with main thoracic adolescent idiopathic scoliosis. All of the patients were fused with hybrid instrumentation (apical concavity-sublaminar wires) and differential rod contouring (over-kyphosis concavity/under-kyphosis convexity). The degrees of the rib hump were measured with a scoliometer placed at the apex of the deformity at five different times: (1) preoperatively through the Adam's test, and during surgery (sterilised scoliometer), (2) with the patient lying prone, (3) after the Ponte osteotomies, (4) after the apical sublaminar tightening, and (5) after convexity apical derotation and compression manoeuvres. (1) Preoperatively, the Adam's test was 16.3°±4.6. (2) Lying prone and under general anaesthesia, it decreased to 11.4°±3.9. (3) After exposure and Ponte osteotomies, it was 7.1°±4. (4) After the wire tightening, it was 10.8°±4.7. (5) After the convexity manoeuvres, it was 4.8°±3.7. The degrees of the rib hump final correction were 11.6°±4 (70% correction). The tightening of the sublaminar wires increased the rib hump by 3.5°. The sublaminar wire tightening towards the concave rod seemed to create an effect opposite of the desired effect, increasing the apical rotation and the thoracic rib hump deformity. Convexity manoeuvres (apical screw derotation and compression) are necessary and must be coupled with an under-bending of the convex rod to neutralise this effect.

RADIOLOGICAL ASSESSMENT OF BONY UNION AFTER OCCIPITOCERVICAL FUSION

Study design: Assessment of posterior occipitocervical fusions, based on the post-operative (postop) follow-up radiographic findings. Objectives: To investigate an objective radiological evaluation method of the occipitocervical stabilization and fusion. Summary of Background data: For evaluation of the union of the non-instrumented or instrumented stabilization and bony fusion of the occipitocervical segments, only a few studies have been performed by some previous authors. Material and Methods: Occipitocervical fusions were performed in 20 patients from 1995 to 2007. The patients underwent occipitocervical fusions with 4 different surgical methods; autogenous iliac bone grafts and wire fixation (seven cases), loop and sublaminar wire fixation (five cases), Cotrel–Dubousse (CD) occipitocervical rod (two cases), and contoured reconstruction plate and screw systems (six cases). The stability and established union of the fused segment and the instrument failure or loosening were evaluated with flexion/extension lateral radiograms. The stability was evaluated by alignment change in degrees and distances between a point of the occiput and cervical vertebrae on the sagittal plane radiograms, taken at postop three months ago. Angular motion over 2[Formula: see text] and 2[Formula: see text]mm of displacement on radiograms were defined to be unstable and/or ununited. When there was no such motion of the fused segment and the instrument breakage or loosening, the fused segment was judged stable and fused. Results: Diagnosis of nonunion was made in three out of seven patients who have undergone fusion with autogenous bone grafts with wire fixation. In the other patients, we were unable to determine the presence of a solid fusion mass at the fusion site, because of overlapping of the instrument and graft bones. In all rigidly instrumented cases, stability was obtained. Conclusion: The occipitocervical fusion segments were judged clinically to be stabilized rather than fused, if the flexion/extension radiographs, taken at postop three and six months, did not demonstrate motion at the fusion site.

Kyphectomy in Children With Severe Myelomeningocele-Related Kyphosis

Study DesignRetrospective review of prospectively maintained database. ObjectivesTo review myelomeningocele patients with severe kyphosis undergoing kyphectomy surgery in terms of complications and clinical and radiographic outcomes. Summary of Background DataBecause of posterior element abnormality in myelomeningocele, the extensor muscles act as perverted flexors, driving progressive kyphosis that resulted in sitting, respiratory, and skin breakdown problems. MethodsClinical case notes and x-rays of seven myelomeningocele patients undergoing kyphectomy surgery were reviewed with a minimum follow-up of 24 months. They consisted of four males and three females with an average age of 9.5 years at surgery. Surgery was performed in three despite open pressure ulcers that failed to heal. These wounds were all closed primarily at initial operation, and no flaps were required. Pedicle screw and sublaminar wire constructs were utilized with iliac screws for distal control. ResultsThe median surgical time was 245 minutes (165–285), with an estimated blood loss of 700 mL (500–2,550). The preoperative kyphosis of 142 degrees (90–180) was corrected to 15 degrees (5–45) representing a 92% correction. All experienced improved sitting. There were no early complications but 2 patients with preoperative pressure ulcers returned at 13 months with recurrent sepsis and wound breakdown. Their osteotomy had fused, and the infection settled after instrumentation removal and antibiotic administration. ConclusionAlthough an infrequent presentation today, severe kyphosis in myelomeningocele patients causes not only a major functional impairment but threat to their life with apical pressure sores. Kyphectomy and posterior instrumented spinal fusion can be performed safely, even in the face of an open sore with excellent kyphotic correction and resultant improved functionality and ability to sit. These open sores can be closed primarily without the requirement of plastic surgery as a result of the shortening and extension of the spine.

Focusing on the delayed complications of fusing occipital squama to cervical spine for stabilization of congenital atlantoaxial dislocation and basilar invagination

ObjectivesOccipito-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. Patients and methodsTwenty 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 (>12months) and delayed complications in these patients were analyzed. ResultsFive 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. ConclusionProgressive 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.

Three Dimensional Correction of Severe Rigid Neurofibromatosis Scoliosis

Introduction 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 curves and the delicate nature of the dural sac. The aim of this work is to review the clinical and radiographic outcome of three-dimensional correction of severe rigid neurofibromatosis curves analyzing its efficacy, safety and possible complications. Materials and Methods The results of 32 patients with severe rigid neurofibromatosis deformities were retrospectively reviewed. Patients were followed-up for a minimum of 3 years; an average of 6.5y (range 3 – 9y). The average age was 14 years (range 11 – 19y). All patients had typical dystrophic curves and the apex of the deformity was dorsal (13 patients); dorsolumbar (14 patients) and lumbar (5 patients). All patients had a two staged procedure; an anterior release followed by posterior instrumentation augmented by sublaminar wires. The wires were placed immediately below the proximal anchor and several sublaminar wires 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). Results The mean Cobb angle of the main curve was 102° before surgery corrected to an average of 39° and the loss of correction had an average of 4°. Sagittal alignment improved from an average of 12° to an average of 47° and rotation was corrected by an average of 34%. There were no dural tears during passage of the sublaminar wires and no neurological or implant related complications. Conclusions The use of extensive and vigorous anterior release with posterior hybrid instrumentation has proved useful and effective in the treatment of these difficult cases; sublaminar wires allow safe gradual correction and even distribution of forces over multiple anchor points improving the correction achieved and decreasing implant related complications.

All Pedicle Screw Instrumentation for Scheuermann's Kyphosis Correction

Introduction Scheuermann's kyphosis has long been treated by a two staged fusion and instrumentation with a hybrid construct using hooks, pedicle screws and sublaminar wires. Interest in all pedicle screws constructs led to its use in the treatment of Scheuermann's kyphosis. Materials and Methods The study included 18 patients who underwent a single stage correction by segmental all pedicle screw constructs (Group 1) and 17 who underwent a two staged fusion and instrumentation with a hybrid construct (Group 2). The average age was 16y+3m and 16y+8m respectively. The average preoperative dorsal kyphosis was 88 degrees (Group 1) and 80 degrees (Group 2). Results Both groups were followed for a minimum of 2 years. The deformity correction of Group 1 had an average of 57% postoperatively with 2.2% loss at final follow-up in comparison to Group 2 where the correction was 48% postoperatively with 3% loss at final follow-up. The operative time was considerably less in Group 1 with an average of 3.5 hour than Group 2 with an average of 5.15 hour. The average blood loss was 550 cc in Group 1 and 910 cc in Group 2. Conclusions The use of multiple levels all pedicle screws technique allowed a rigid anchor for posterior correction of the deformity with less operative time, blood loss, hospital stay without the need for anterior release.

A Novel Technique to Reconstruct Anterior Cervical Spine after Total Removal of C2 and C3 Vertebrae

Introduction Reconstruction of C2 body in cases who need removal of C2 body and Axis is a challenging issue, due to difficult approach and small area for instrumentation and grafting, especially in pediatric age group. Material and Methods Our patient underwent a two-stage surgery. During the first operation via a posterior approach, a subtotal resection of a C2 bony mass was performed. C3 was also subtotally resected due to tumor extension. Posterior fixation of C1–C5 was performed by C1 sublaminar hooks and C4 and C5 lateral mass screws. Ten days later, a total resection of the residual bony mass was performed through an anterior approach (between the sternocleidomastoid muscle and carotid sheath). Reconstruction of C1–C3 was performed with C1 anterior sublaminar wiring and an expandable titanium cage. Results Successful reconstruction of C2–C3 vertebral bodies was achieved. At 2-year follow-up, the child was symptom-free. Imaging studies revealed no recurrence of tumor or instability. Conclusion A novel technique for reconstruction of C2–C3 vertebral bodies is demonstrated for the youngest case (a 6-year-old boy) of osteoblastoma in the literature. We recommend this approach for cervical spine reconstruction in patients who have an intact C1 arc and resected lower bodies.

Surgical outcome of scoliosis correction in Duchenne muscular dystrophy (DMD) using different instrumentation constructs

BACKGROUND CONTEXT: With the advent of newer instrumentation systems, ie, pedicle screw (PS), there has been a recent trend towards its use in neuromuscular scoliosis and DMD. However sublaminar wire (SW) is still widely used; we therefore compared our results with these two techniques.

Comparison of segmental pedicle screws versus hybrid constructs using sublaminar wires for deformity correction in cerebral palsy (CP)

Comparison of segmental pedicle screws versus hybrid constructs using sublaminar wires for deformity correction in cerebral palsy (CP)

Short to Mid-Term Term Surgical Outcome Study with Posterior Only Approach on Tuberculous Spondylodiscitis in an Elderly Population.

Study DesignRetrospective study.PurposeTo study short to mid-term outcome of surgically managed elderly patients of tuberculous spondylodiscitis with posterior only approach in terms of decision making and challenges in treatment, choice of implants and outcomes.Overview of LiteratureTuberculous spondylodiscitis in the elderly is increasing due to longer survival rates. It presents with varied clinical manifestations needing surgical management. Management in tuberculous spondylodiscitis has been scarcely reported in the elderly, with a paucity of data on the choice of implants and approach.MethodsSixteen patients (five males, 11 females) older than 70-years-of-age culture and/or histopathology proven tuberculous spondylodiscitis were included in the study. All patients were operated using a single posterior approach. Pedicle screw with rods (PS/rods) or spinal loop with sublaminar wires (SL/SLW) were used for fixation. Clinical and surgical details were recorded. Sagittal correction achieved postoperatively and loss of correction at follow-up were noted.ResultsThe mean age was 73.6 years (range, 70 to 80 years). The mean follow up was 44.5 months (range, 24 to 84 months). The mean immediate postoperative correction of sagittal deformity was 11.3 degrees; this correction was lost by a mean of 3.1 degrees at last follow-up. All 10 patients with deficit showed neurological recovery and all but one of the seven non-walkers were capable of independent ambulation at follow-up. Patients with SL/SLW and PS/rods had similar radiological outcome at final follow up.ConclusionsOperative management gives satisfactory results in elderly patients with tuberculous spondylodiscitis. The posterior approach provides adequate exposure for decompression and rigid fixation, providing satisfactory clinical and radiological outcomes. SSL/SLW and pedicle screw rod construct both give similar radiological results if used appropriately in patients.

Surgical Intervention for Instability of the Craniovertebral Junction.

Surgical approaches for stabilizing the craniovertebral junction (CVJ) are classified as either anterior or posterior approaches. Among the anterior approaches, the established method is anterior odontoid screw fixation. Posterior approaches are classified as either atlanto-axial fixation or occipito-cervical (O-C) fixation. Spinal instrumentation using anchor screws and rods has become a popular method for posterior cervical fixation. Because this method achieves greater stability and higher success rates for fusion without the risk of sublaminar wiring, it has become a substitute for previous methods that used bone grafting and wiring. Several types of anchor screws are available, including C1/2 transarticular, C1 lateral mass, C2 pedicle, and translaminar screws. Appropriate anchor screws should be selected according to characteristics such as technical feasibility, safety, and strength. With these stronger anchor screws, shorter fixation has become possible. The present review discusses the current status of surgical interventions for stabilizing the CVJ.

Rigid Instrumentation for Neuromuscular Scoliosis Improves Deformity Correction Without Increasing Complications.

Retrospective chart and radiographic review. To evaluate spinopelvic fixation technical advancements for the treatment of neuromuscular scoliosis. Implants for vertebral and pelvic fixation have evolved without data demonstrating the benefit for neuromuscular scoliosis. The aim of this study was to evaluate this evolution in terms of deformity correction, complications, and implant cost. Patients treated with posterior spinal fusion to the pelvis for neuromuscular scoliosis with minimum 1-year follow-up from 1998 to 2012 were reviewed. Constructs were defined as nonrigid (>50% sublaminar wire fixation with Galveston or iliac screw pelvic fixation) and rigid (≥50% pedicle screw fixation with iliac or sacral alar iliac screw pelvic fixation). Eighty patients were identified: cerebral palsy (55%), myelomeningocele (16%), syndrome (8%), muscular dystrophy (15%), or other neuromuscular disorders (6%). A total of 95% were nonambulatory. Mean follow-up was 3.9 years (range 1-12 years). Construct types were 23 nonrigid and 57 rigid. Estimated construct cost was greater in the rigid group at $15,488 as compared with $3128 in the nonrigid group despite the lower anchor density in the rigid construct group (1.38 vs. 1.80, P < 0.001). Open anterior releases were more frequently performed in the nonrigid group (13/23 vs. 5/57, P < 0.001). Deformity correction at final follow-up was significantly greater for both Cobb angle and pelvic obliquity in the rigid group. The rates of wound infection, wound dehiscence, implant prominence, and mechanical failure of the fixation were not significantly different. The pseudarthrosis rate requiring revision surgery was 22% in nonrigid group and 5% in the rigid group (P = 0.026). Advances in spinopelvic fixation have resulted in improved deformity correction with lower rates of pseudarthrosis and a decreased need for anterior release. This study demonstrates the benefits of modern spinopelvic fixation techniques.

A Cost-Effective Technique for Spinal Instrumentation in the Treatment of Adolescent Idiopathic Scoliosis.

Surgical treatment for adolescent idiopathic scoliosis (AIS) has evolved over the past decades to the point where instrumented arthrodesis with all pedicle screw and rod constructs is commonplace. Although these constructs provide superb correction and fixation, their financial burden is substantial. Here, we present a more cost-effective technique using a combination of pedicle screws (serving as the construct base), a sagittal precontoured unit rod, and sublaminar wires to provide segmental correction for the surgical treatment of AIS. Retrospective analyses of 42 patients treated with this construct were reviewed with a minimum 2-year follow-up. Correction in both coronal and sagittal planes was assessed radiographically and blood loss, operative time, complications, and cost were reviewed from hospital records. We conclude that this technique provides comparable correction to all pedicle screw constructs with similar blood loss and operative time, but with substantially decreased implant cost. The mean implant cost was $8910.83 ± $184.26.