Spinal Instrumentation Systems Research Articles

Role of growth modulation in the management of idiopathic scoliosis: A narrative review of literature

Scoliosis is a condition in which there is a lateral curve to the spine. The cause of scoliosis is unknown, but different aetiologies have been suggested, but mostly cause has been idiopathic in nature. Muscle spasms, cerebral palsy, Marfan syndrome, and tumours (neurofibromatosis) are some of the suggested aetiologies. Progressive adolescent idiopathic scoliosis (AIS) affects mainly girls and anterior spinal overgrowth during the second growth spurt appear to be a significant cause. The diagnosis of scoliosis is primarily a clinical suspicion followed by an AP and lateral X ray of spine in standing position. Measurement of the Cobb angle is the standard method of assessing the curvature in a quantitative manner. It is the angle between two lines, drawn perpendicular to the upper endplate of the first vertebra involved and the lower endplate of the last vertebra involved. Cobb angles are followed for both curves for those with two curves. Risser classification grades the skeletal maturity on X rays and is considered along with the Cobb angle to making a decision towards surgery. Indications for surgical correction of scoliosis is not clearly defined however, the treatment of scoliosis is based on the severity and progressive nature of the curve. Cobb angle above 40 degrees, rapidly progressing curve, major thoracic deformity affecting the function such as breathing and cosmetic reasons, are some of the indications for surgery. There are several modalities of surgical correction. Main method has been correction of the deformity and fixation with one or two rods and pedicle screws followed by bone grafting. Harrington rods were the primarily used system, but with time many spinal instrumentation systems and rods have been introduced to the market. Apart from using rods some have tried anterior vertebral body stapling and anterior vertebral body tethering for correction scoliosis using the principle of growth modulation.
 We conducted a systematic review to answer the question, 'What is the role of growth modulation in the management of idiopathic scoliosis?' All articles / publications published from 2010 May to 2019 October were used as research data. A health, related database (PubMed) was used for the search. Search criteria revealed 99 articles initially and 37 articles after filtered based on title reading. Then 18 articles were selected for the final analysis after being filtered manually by reading summary and abstracts of each article.

Spring distraction system for dynamic growth guidance of early onset scoliosis: two-year prospective follow-up of 24 patients

BackgroundCurrent surgical treatment options for early onset scoliosis (EOS), with distraction- or growth-guidance implants, show limited growth and high complication rates during follow-up. We developed a novel implant concept, which uses compressed helical springs positioned around the rods of a growth-guidance construct. This spring distraction system (SDS) provides continuous corrective force to stimulate spinal growth, can be easily contoured, and can be used with all standard spinal instrumentation systems. PurposeTo assess curve correction and -maintenance, spinal growth, complication rate, and health-related quality of life following SDS treatment. Study DesignProspective cohort study. Patient sampleAll skeletally immature EOS patients with an indication for growth-friendly surgery and without bone- or soft tissue weakness were eligible to receive SDS. For this study, all included patients with at least 2-year follow-up were analyzed. Outcome measuresCoronal Cobb angle, sagittal parameters, T1-T12, T1-S1, and instrumented (ie, bridged segment) spinal height and freehand length, complications and re-operations, and the 24-Item Early Onset Scoliosis Questionnaires (EOSQ-24) score. MethodsAll primary- and conversion patients (conversion from failed other systems) with SDS and ≥2 years follow-up were included. Radiographic parameters were compared preoperatively, postoperatively and at latest follow-up. Spinal length increase was expressed as mm/year. ResultsTwenty-four skeletally immature EOS patients (18 primary and 6 conversion cases) were included. There were five idiopathic, seven congenital, three syndromic, and nine neuromuscular EOS patients. Mean age at implantation was 9.1 years (primary: 8.4; conversion: 11.2). Major curve improved from 60.3° to 35.3°, and was maintained at 40.6° at latest follow-up. Mean spring length increase during follow-up was 10.4 mm/year. T1-S1 height increased 9.9mm/year and the instrumented segment height showed a mean increase of 0.7 mm/segment/year. EOSQ-24 scores dropped after surgery from 75.6 to 67.4 but recovered to 75.0 at latest follow-up. In total, 17 reoperations were performed. Ten reoperations were performed to treat 9 implant-related complications. In addition, 7 patients showed spinal growth that exceeded expected growth velocity; their springs were retensioned during a small reoperation. ConclusionThe 2-year follow-up results from this prospective cohort study indicate that the concept of spring distraction may be feasible as an alternative to current growing spine solutions. Curve correction and growth could be maintained satisfactory without the need for repetitive lengthening procedures. However, as in all growth-friendly implants, complications and reoperations could not be prevented, which emphasizes the need for further improvement.

Combined Anterior-Posterior Versus Posterior-only Spinal Fusion in Treating Dystrophic Neurofibromatosis Scoliosis With Modern Instrumentation: A Systematic Review and Meta-analysis.

This is a systematic review and meta-analysis study. To compare the efficacy, long-term stability, and safety of combined anterior-posterior spinal fusion (APSF) with posterior-only spinal fusion (PSF) in treating dystrophic neurofibromatosis scoliosis with the use of modern instrumentation. When the Harrington or Luque technique was used, APSF had relatively reliable results and had been recommended by many authors. But with the development of instrumentation and techniques, many surgeons performed PSF with satisfactory results. No systematic review and meta-analysis have been conducted to compare the outcomes of the 2 approaches. Relevant studies on anterior-posterior or posterior fusion of dystrophic neurofibromatosis scoliosis were retrieved from the PubMed, Embase, Cochrane, Springer Link, and Google Scholar databases. Then studies were manually selected for inclusion based on predefined criteria. Data extraction and quality assessment were conducted, and a systematic review and meta-analysis were performed. Sixteen eligible studies were included. The angles of scoliosis curves and kyphosis curves were significantly and similarly corrected after surgery in both APSF and PSF group, respectively. At the last follow-up, the loss of correction was significant in the coronal plane but not in the sagittal plane with a similar progression of scoliosis in 2 groups. The overall complication rate was slightly higher in the APSF group, but the difference was not statistically significant. Meanwhile, there was no visible difference in the incidence of pseudarthrosis and instrumentation failures between the 2 groups. APSF and PSF by means of the third-generation spinal instrumentation system have similar efficacy, long-term stability, and safety for treating dystrophic scoliosis secondary to type-1 neurofibromatosis. Level III-systematic review and meta-analysis study.

Potential risk factors in development of the “halo sign” in patients performed transpedicular screw fixation through the posterior spinal approach.

It has been shown in literature that a fibrous tissue called "halo sign" in the radiological terminology can develop around the transpedicular screws implanted incompletely and/or incorrectly, which appears after movement of the screw in the cancellous bone. In this retrospective clinical study, 141 patients who underwent posterior spinal instrumentation for thoracic, lumbar or thoracolumbar vertebrae were evaluated using computed tomography (CT) and direct X-rays images for "halo sign" formation which refers in probable failure of spinal instrumentation. Hospital records included in the year 2014-2018 were examined and adult patients who were performed lumbar, thoracal, and thoracolumbar spinal instrumentation via posterior approach due to reasons such as "spine fracture", "spondylosis", "spondylolisthesis" and "intervertebral disc hernia" were included and evaluated in this study. The age and sex of the patients were recorded. Spinal X-ray and spinal CT images obtained during the postoperative follow-up period were examined. Halo sign was seen in 13 patients. Age (p=0.013), number of instrumented vertebrae (p=0.001) and number of transpedicular screws (p<0.001) values were different between the patients with halo sign and patients without halo sign. As a result, it was observed in this study that the formation of the halo sign in posterior spinal instrumentation system could develop in proportion to the number of transpedicular screw and patients' age. It was thought that the halo sign formation was not connected with the parameters called performed laminectomy, gender, inserted intervertebral cage, or vertebral region which were inserted transpedicular screws.

Early-Onset Spinal Deformity in Skeletal Dysplasias: A Multicenter Study of Growth-Friendly Systems

PurposeSevere, early-onset spinal deformity is common in patients with skeletal dysplasia. These deformities often present at young ages and are associated with significant pulmonary dysfunction. The objective of this study is to verify the effectiveness of growth-friendly spinal instrumentation systems in promoting growth in patients with skeletal dysplasia and early-onset kyphoscoliosis. MethodsA retrospective, multicenter comparative cohort study was performed. Twenty-three patients identified to have a skeletal dysplasia (SKD) were evaluated for diagnosis, age at treatment, gender, and type of growing rod construct (spine vs. rib constructs). Patients were matched by age and construct type with similarly treated patients with early-onset scoliosis (CON) without skeletal dysplasia. Radiographic parameters including maximum coronal and sagittal Cobb angle with levels, T1–S1 height, and T1–T12 height were measured. ResultsT1–T12 (12.8 vs. 15.2 cm, p = .01) and T1–S1 (21.2 vs. 24.5 cm, p = .05) heights were significantly shorter for the SKD group at implantation, and kyphosis tended to be more severe in children with SKD (p = .80 and .07, respectively). Kyphosis did not improve with treatment. Scoliosis improved (p < .01), and ΔT1–T12 and ΔT1–S1 significantly increased in both groups (p < .01). Complication rates were similar between the two groups; however, patients with SKD had more intraoperative monitoring changes and hardware failures (p < .005). ConclusionAlthough patients with SKD start with shorter spine lengths, gains in spine length appear to be comparable to other forms of EOS. Neuromonitoring changes and implant failures are more common in the SKD group. SignificanceThe effectiveness of growth-friendly techniques in promoting growth in early-onset spinal deformities in patients with skeletal dysplasia has not been previously studied. We report the first comprehensive review of this topic. Growth-friendly techniques are an appropriate treatment option in this patient population.

Biomechanical analysis of different cross-link configurations spinal instrumentation systems: a preliminary study

Percutaneous techniques were initially developed in the management of thoraco-lumbar fractures. Initially transmucular systems have been developed, which generally provide less muscle trauma, blood...

Results of Single-Staged Posterior Decompression and Circumferential Fusion Using a Transpedicular Approach to Correct a Kyphotic Deformity due to Thoracolumbar Spinal Tuberculosis.

Study DesignThis is a prospective study.PurposeThe aim of this study was to investigate the results of single-staged posterior decompression and circumferential fusion using a transpedicular approach to correct a kyphotic deformity due to thoracolumbar spinal tuberculosis.Overview of LiteratureSurgical management is frequently an imperative choice to achieve spinal decompression and deformity correction due to tuberculosis to relieve pain, improve neurology, and reconstruct the spine stability. Since the time anterior radical debridement and noninstrumented fusion was described, it has become apparent that even anterior debridement and bone grafting was often unsatisfactory in correcting or preventing the progression of kyphosis deformity. With the advent of modern segmental spinal instrumentation systems, isolated posterior instrumentation; combined anterior and posterior fusion; and single-staged posterior decompression and circumferential fusion have been described by many authors for correcting angular deformity and stabilizing the spine; however, there is a lack of consensus regarding the most effective means of correcting the deformity due to thoracolumbar spinal tuberculosis.MethodsThis is a prospective study of 20 patients with thoracolumbar spinal tuberculosis who underwent surgery at our institute.ResultsTwenty patients who were started on antituberculosis treatment underwent surgery using a single-staged posterior approach involving fixation, decompression, and kyphosis correction. Preoperatively, all patients had varying degrees of neurological deficit and a 27.45° average kyphotic angle, which improved. At the 1-year follow-up, correction was maintained at 6.9°, and 55% of patients showed neurological improvement. None of the patients experienced neurological deterioration. Two patients with lumbar spine tuberculosis underwent revision surgery because of nonunion.ConclusionsThe procedure of posterior decompression, fixation, and circumferential fusion using a transpedicular approach performed for thoracolumbar spinal tuberculosis is effective, safe, and excellent in correcting and maintaining kyphosis.

Efficacy and Risk Factors, for Complications Associated with Growing Rods, in the Management of Progressive Early-Onset Scoliosis

Introduction Growing-rod spinal instrumentation systems are a valuable option for managing progressive early-onset scoliosis. However, some studies had suggested that its efficacy may be lost over a period time and could be counterbalanced by a high rate of complications. The objective of this study was to determine the efficacy and safety of growing rods for the treatment of progressive early-onset scoliosis. Materials and Methods An Institutional Review Board approved cross-sectional study was performed, including patients with early-onset scoliosis treated with growing rods between 1997 and 2012. A retrospective review of the chart and radiographic data were performed. Risk factors for complications were explored using univariate and multivariate analyses. Results Records of 35 patients were included. The mean age at implantation of the rods was 5.8 ± 2.3 years. Overall, 18 patients had a diagnosis of idiopathic scoliosis, 11 with congenital scoliosis, and 6 with neuromuscular scoliosis. The mean Cobb measurement for the preoperative major curves was 66.7 ± 14.4 (range, 42–98) degrees. After a mean of 4 ± 1.4 lengthening procedures, there was a statistically significant improvement in the coronal plane deformity to a mean of 34.9 ± 11.2 degrees ( p &lt; 0.001), resulting in an average decrease of 31.8 ± 14.6 degrees. Following complications have occurred in 11 patients (31.4%): implant failure/fracture (22.9%), surgical site infection (5.7%), and transient brachial plexus injury (2.8%). The only risk factor associated with the presentation of postoperative complications was the total number of lengthening procedures (OR = 2.79). Conclusion Growing rods are effective for reduction of the magnitude of the spinal deformities in patients with progressive early-onset scoliosis before the definite fusion. However, this treatment is related with a relatively high rate of postoperative complications. Those complications appear to be associated with the total number of lengthening procedures previous to the definitive fusion. Therefore, it is advisable to reduce the frequency of lengthening as much as needed for maintaining the correction and allow the longitudinal growing of the spine.

Chemical and Heat Treatments for Inducing Bone-Bonding Ability of Ti-6Al-4V Pedicle Screw

Pedicle screw (PS) system using Ti-6Al-4V PSs became popular in spinal instrumentation system. However, they sometimes case loosening and back-out from bone because of their poor bone-bonding ability. In the present study, Ti-6Al-4V alloy was subjected to the acid-heat or calcium-heat treatments that are effective for inducing high capacities of apatite formation and bone bonding on pure Ti. When the alloy was subjected to the acid-heat treatment, a surface layer composed of rutile and anatase TiO2 enriched with Al and V was produced. Thus the treated alloy was neutrally charged and did not form apatite in a simulated body fluid (SBF) even after 3 day. In contrast, when the alloy was subjected to the Ca-heat treatment, a surface layer composed of calcium titanate, anatase and rutile free from Al and V was produced. The treated alloy formed apatite in SBF within 3 days. When the Ti-6Al-4V PSs subjected to the Ca-heat treatment was implanted into vertebra of beagle dogs, they showed higher bone-bonding ability as well as bone contact area than those without the treatment. This kind of bioactive Ti-6Al-4V PSs might be useful for spinal instrumentation since they could prevent loosening and back-out from bone.

Biomechanical analysis of spinal instrumentation systems dedicated to stabilise thoracolumbar fractures: comparison between standard open surgical instrumentation and percutaneous techniques

Thoracolumbar burst fractures represent an important part of spine injuries. Burst fractures are usually caused by dynamic axial compression of spine segments. This leads to an inherent instability and then a spinal cord compression. A surgical treatment is needed for most of the cases to restore bone stability, prevent neurological deterioration and provide pain relief. Classically, posterior instrumentations using rods and pedicle screws are performed under open surgical approaches and eventually associated with corpectomy and/or anterior fixation, in case of anterior column threatening instability. However, the choice of the type of surgery might progressively change in favour of minimally invasive techniques. Indeed, burst fracture stabilization using a short posterior instrumentation and/or vertebral balloon expansion followed by an injection of cement (kyphoplasty), with a pure percutaneous approach, can help to reduce morbidity for these patients. However some keypoints need to be clarified about these techniques with a focus on their biomechanical effectiveness. The purpose of this study was to compare mechanical behaviour under physiological loadings of four types of stabilizations devices, including 2 open instrumentations and 2 percutaneous techniques: classical Posterior Fixation standalone (PF); Posterior Fixation associated with anterior screwed Cage-Plate, following a corpectomy of the fractured vertebra (PF-CP); percutaneous Kyphoplasty standalone (K); percutaneous Kyphoplasty and Posterior Fixation (K-PF).

PEEK rod systems for the spine

Traditional materials for the spine such as titanium and stainless steel have produced satisfying long-term fusion rates, mainly due to their strength and stiffness. However, although fixation with titanium rods leads to high fusion rates, increased stiffness of titanium constructs may also contribute to stress shielding and adjacent segment degeneration. Dynamic and flexible materials such as the Dynesys system allow better stress distribution to all of the spinal columns, but increase the rate of complications including screw loosening, infection, back and leg pain, and endplate vertebral fracture. Semi-rigid instrumentation systems using rods made from synthetic polymers such as the polyetheretherketone (PEEK) have been recently introduced as an alternative biomaterial for the spine. PEEK is a fully biocompatible and inert semi-crystalline thermoplastic polymer with minimal toxicity; it has a modulus of elasticity between that of cortical and cancellous bone, and significantly lower than titanium. However, there are very few clinical studies with small sample size and short-term follow-up using PEEK rod-pedicle screw spinal instrumentation systems. Additionally, their results are conflicting. To enhance the literature, this review discusses the effect of this medical for the spine and summarizes the results of the most important related series.

Growing-Rod Graduates: Lessons Learned from Ninety-nine Patients Who Completed Lengthening

Growing-rod spinal instrumentation systems are a valuable tool for managing severe early-onset scoliosis. There is little information about the end point of treatment. A multicenter early-onset-scoliosis database was searched to identify patients who had undergone treatment with growing rods and either had had a final operative procedure or were still being treated with the growing rods after reaching skeletal maturity (defined as fourteen years of age or older). Clinical, radiographic, and operative data were analyzed. Ninety-nine patients met the inclusion criteria, and ninety-two (93%) of them had had a final operative procedure. The remaining seven patients (7%) were older than fourteen years but had not undergone a final procedure. Of the ninety-two patients who had a final procedure, seventy-nine (86%) had an instrumented fusion, nine (10%) had growing-rod exchanges and fusion in situ, three (3%) had the growing rods left in place and fusion in situ, and one (1%) had only growing-rod removal. The mean age (and standard deviation) at the final fusion was 12.4 ± 1.9 years. In forty-four (55%) of eighty patients for whom the information was available, the number of vertebral levels fused was the same as the number of vertebral levels spanned by the growing rods. The percent correction of the curve after final fusion was none or minimal (≤ 20 %) in eleven (18%) of the sixty-two patients for whom sufficient-quality radiographs were available, moderate (21% to 50%) in thirty (48%), and substantial (≥ 51 %) in nine (15%); the curve had worsened in twelve patients (19%). The mean duration of growing-rod treatment was 5.0 ± 2.6 years. Of fifty-eight operative reports made at final fusion that contained comments on spinal flexibility, eleven (19%) described the spine as being mobile, eleven (19%) described decreased flexibility, and thirty-six (62%) described the spine as being completely stiff. At final fusion, twenty-two patients (24%) had osteotomies and seven patients (8%) had a thoracoplasty. Most patients underwent growing-rod removal and final instrumented fusion. The final fusion often included the same levels spanned by the growing rods and usually achieved <50% additional correction of the deformity remaining at the end of the growing-rod management. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Posterior Spinal Fusion Using Pedicle Screws

Few clinical studies have reported polyetheretherketone (PEEK) rod pedicle screw spinal instrumentation systems (CD-Horizon Legacy PEEK rods; Medtronic, Minneapolis, Minnesota). This article describes a clinical series of 52 patients who underwent posterior spinal fusion using the PEEK Rod System between 2007 and 2010. Of the 52 patients, 25 had degenerative disk disease, 10 had lateral recess stenosis, 6 had degenerative spondylolisthesis, 6 had lumbar spine vertebral fracture, 4 had combined lateral recess stenosis and degenerative spondylolisthesis, and 1 had an L5 giant cell tumor. Ten patients had 1-segment fusion, 29 had 2-segment fusion, and 13 had 3-segment fusion. Mean follow-up was 3 years (range, 1.5-4 years); no patient was lost to follow-up. Clinical evaluation was performed using the Oswestry Disability Index and a low back and leg visual analog pain scale. Imaging evaluation of fusion was performed with standard and dynamic radiographs. Complications were recorded. Mean Oswestry Disability Index scores improved from 76% preoperatively (range, 52%-90%) to 48% at 6 weeks postoperatively, and to 34%, 28%, and 30% at 3, 6, and 12 months postoperatively, respectively. Mean low back and leg pain improved from 8 and 9 points preoperatively, respectively, to 6 and 5 points immediately postoperatively, respectively, and to 2 points each thereafter. Imaging union of the arthrodesis was observed in 50 (96%) patients by 1-year follow-up. Two patients sustained screw breakage: 1 had painful loss of sagittal alignment of the lumbar spine and underwent revision spinal surgery with pedicle screws and titanium rods and the other had superficial wound infection and was treated with wound dressing changes and antibiotics for 6 weeks. No adjacent segment degeneration was observed in any patient until the time of this writing.

SURGICAL CORRECTION OF SCHEUERMANN’S KYPHOSIS IN CHILDREN

Objective. To present specific surgical technique for juvenile kyphosis correction and analyze results of surgical treatment for spinal deformity in children with Scheuermann’s disease using transpedicular spinal instrumentation systems. Material and Methods. The study included ten patients aged 14 to 17 years with kyphotic spinal deformity associated with Scheuermann’s disease. The mean deformity magnitude was 73.1° (range, 60° to 90°). Kyphosis apex was located at the T7 (n = 5), T8 (n = 1), T9 (n = 3), or T10 (n = 1) level. Surgical intervention was performed through combined approach using disc-apophysis-ectomy and fusion at the apex of kyphosis, and placement of multiple anchor spinal instrumentation. Results. Five patients received the hybrid instrumentation, and other five – transpedicular one. Surgical treatment resulted in reduction of kyphosis to 32.1° with average deformity correction of 41°. Average number of fixed vertebrae in patients with hybrid instrumentation was 14, and in those with total transpedicular fixation – 13. The loss of correction in the long-term follow-up was observed in patients with hybrid multiple anchor instrumentation. Conclusion. The use of pedicle screws as anchors in surgical treatment of juvenile kyphosis in children with Scheuermann’s disease allows for effective deformity correction, restoration of physiological profiles of the spine, elimination of postoperative curve progression, shortening of instrumentation length, prevention of junctional kyphosis development, and maintaining of the achieved results.

Biomechanical Study Comparing a New Combined Rod-plate System With Conventional Dual-rod and Plate Systems

Most anterior spinal instrumentation systems are designed as either a plate or dual-rod system and have corresponding limitations. Dual-rod designs may offer greater adjustability; however, this system also maintains a high profile and lacks a locking design. Plate systems are designed to be stiffer, but the fixed configuration is not adaptable to the variety of vertebral body shapes. The authors designed a new combined rod-plate system (D-rod) to overcome these limitations and compared its biomechanical performance with the conventional dual-rod and plate system. Eighteen pig spinal specimens were divided into 3 groups (6 per group). An L1 corpectomy was performed and fixed with the D-rod (group A; n=6), Z-plate (Sofamor Danek, Memphis, Tennessee) (group B; n=6), or Ventrofix (Synthes, Paoli, Pennsylvania) (group C; n=6) system. T13-L2 range of motion was measured with a 6 degrees of freedom (ie, flexion-extension, lateral bending, and axial rotation) spine simulator under pure moments of 6.0 Nm. The D-rod and Ventrofix specimens were significantly stiffer than the Z-plate specimens (P<.05) based on results obtained from lateral bending and flexion-extension tests. The D-rod and Z-plate specimens were significantly stiffer than the Ventrofix specimens (P<.05) in axial rotation. The D-rod combines the advantages of the plate and dual-rod systems, where the anterior rod exhibits the design of a low-profile locking plate, enhanced stability, and decreased interference of the surrounding vasculature. The posterior rods function in compression and distraction, and the dual-rod system offers greater adjustability and control over screw placement. The results indicate that it may provide adequate stability for anterior thoracolumbar reconstruction.

The lasting legacy of Paul Randall Harrington to pediatric spine surgery

Spinal arthrodesis was the first successful treatment for scoliosis, performed by Dr. Russell A. Hibbs in 1911 and later by Dr. Fred H. Albee for tuberculosis. In 1914, Dr. H.P.H. Galloway and Dr. Hibbs began using the method to treat neuromuscular scoliosis in patients with poliomyelitis. However, this treatment approach was plagued by loss of deformity correction over time and high pseudarthrosis rates. The turning point in the operative management of spinal deformities began in 1947 with Dr. Paul Randall Harrington when he started a decade-long process to revolutionize surgical treatment of spinal deformities culminating in the advent of the Harrington Rod, the first successful implantable spinal instrumentation system. During the epoch that he was in practice, Dr. Harrington's achievement influenced the technology and art of spine surgery for his contemporaries and the coming generations of spine surgeons. The purpose of this article is to review the life of Dr. Harrington, and how he has arguably come to be known as "Father of the Modern Treatment of Scoliosis."

Lumbopelvic fusion with a new fixation technique in lumbosacral agenesis: Three cases

Patients with lumbosacral agenesis characteristically sit on their iliac wings with their torsos bent forward, which yields an increase in intra-abdominal pressure and, subsequently, negative effects on their diaphragm. The sacrum is not available as an anchor point for instrumentation. Dunn-McCarthy rods or Galveston fixations cannot be performed due to these limited anatomic properties. On the other hand, the absence of necessary bone mass for fusion anteriorly limits the fusion interventions to the posterior. Therefore, a secure and rigid fixation is essential to preclude the need for an external support. There are limited publications discussing different techniques due to the relatively rare incidence of the disease. We report the clinical and radiological results of a new technique applied to three patients in which previously recommended methods are modified. Two 6-year-old female patients and one 5-year-old male patient with lumbosacral agenesis underwent posterior lumbopelvic instrumentation and fusion. Together with standard pedicle screw spinal instrumentation, pelvic fixation is obtained with a combination of supero-inferior directed rod and/or screw to overcome deforming forces created at the flexion-extension pivot points of the lumbopelvic junction. Autogenic anterior tibial cortical structural graft is used for laminopelvic bridging, and demineralized bone matrix is used for the augmentation of osteoinduction. A single leg hip spica is applied for 4months to protect the fixation. Total correction yielded an aligned spine with a posture that allows for sitting on the ischial spines for all three patients. Solid fusion was observed to maintain this correction at the final follow-up. The use of new-generation pediatric spinal instrumentation systems with a new technique without knee disarticulation provides a safe and effective fixation and fusion in lumbosacral agenesis.

Posterior scoliosis correction for adolescent idiopathic scoliosis using side-opening pedicle screw-rod system utilizing the axial translation technique

Background:Though adequate literature is present depicting the results of pedicle screw-rod instrumentation using top loading systems for correction of adolescent idiopathic scoliosis (AIS), using the rod rotation technique, few published data is available regarding side loading systems used for a similar purpose. We report a retrospective study of a cohort of patients with strict inclusion criteria who underwent surgical correction of AIS with side-opening pedicle screw-rod posterior instrumentation using the axial translation technique of curve correction to assess the efficacy of side opening system for scoliosis correction with regards to patient satisfaction, Cobb's angle correction and spinal balance.Materials and Methods:Clinical and radiological outcomes were measured in 14 consecutive patients (3 males, 11 females) with an average age of 14.0 years (range 9 to 23 years). They were followed up for an average period of 13.0 months (range – 2.2 to 28.5). All patients underwent posterior instrumentation only with pedicle screws used as anchor points. Hybrid constructs using hooks/wires or curves requiring anterior release were excluded from the study. All levels were not instrumented – more screws were put on the concavity and in the peri-apical region. Radiological evaluation was done by whole spine standing AP, lateral radiograms preoperatively and 1, 3, 6 and12 months after surgery. Cobb's angles were measured and the spinal balance was noted. Clinical evaluation was done by SRS questionnaire. The complications were documented.Results:The mean preoperative Cobb's angle was 58.35° (range – 44 to 72°), which came down postoperatively to 23.45° (range – 10 to 38°) signifying a mean correction of 59.57% (range – 26.92 to 76.17%). Clinical outcomes were evaluated using the SRS – 30 questionnaires. The values of mean pre- and postoperative scores are 3.68 and 4.18, showing an improvement of 0.5 points. Other than one patient of superficial wound infection, which healed with antibiotics, there was no major complication. No patient had neurological deterioration.Conclusion:Side-opening spinal instrumentation systems, using the axial translation technique, achieved good clinical and radiological outcome for patients of AIS.

Analysis of instrumentation/fusion survivorship without reoperation after primary posterior multiple anchor instrumentation and arthrodesis for idiopathic scoliosis

Background During the past 25 years, spinal instrumentation systems and surgical techniques used to treat idiopathic scoliosis have evolved, achieving fewer patient restrictions during arthrodesis healing, shorter constructs, and better correction. The purposes of this retrospective comparative study were to determine the survivorship of the implant/fusion without reoperation and the risk factors influencing such survival. Methods From 1989 through 2002, 208 consecutive patients (index patient included, age 10–20 years) underwent primary posterior instrumentation and arthrodesis with the same multiple anchor implant system by one surgeon, a co-designer of the system. Two hundred seven were followed for more than 2 years; reoperation status was available for them at an average follow-up of 8.3 years. Twenty-one independent demographic, deformity, instrumentation, and process variables possibly influencing the need for reoperation were studied by comparing the reoperated group with the unreoperated group. Results Nineteen patients (9.2%) had reoperation; 16 (7.7%) were for indications related to posterior spine instrumentation. Survival of the implant/fusion without reoperation for spine instrumentation–related indications was 96% (95% confidence interval [CI], 93.2–98.7%) at 5 years, 91.6% (95% CI, 86.9–96.3%) at 10 years, 87.1% (95% CI, 79.5–94.6%) at 15 years, and 73.7% (95% CI, 48.6–98.6%) at 16 years, when the number at risk was nine. Reoperation need was significantly influenced by two implant variables: transverse connector design (p=.0012) and the lower instrumented vertebra anchors used (p=.0004). At 9 years, the longest interval allowing comparison, survival of the implant/fusion without reoperation for these two variables was 100% (six subjects at risk) compared to 82% (95% CI, 74.2–90.3%) with 59 patients still at risk for reoperation for those who did not have them, p=.0014. Conclusions The most stable lower instrumented vertebra anchor configuration, bilateral pedicle screws, and the stronger transverse connector design, closed drop entry, provided the best survival of the implant/fusion without reoperation with this system and the techniques used at 9-year follow-up. We hope that this post-market study using survivorship techniques will be a guide for studies of other spinal implants.

OUTSTANDING PAPER: SURGICAL SCIENCE Analysis of Instrumentation/Fusion Survivorship without Reoperation Following Primary Posterior Multiple Anchor Instrumentation and Arthrodesis for Idiopathic Scoliosis

BACKGROUND CONTEXT: During the past twenty-five years spinal instrumentation systems and surgical techniques used to treat idiopathic scoliosis have evolved, achieving fewer patient restrictions during arthrodesis healing, shorter constructs, and better correction.