Safety and efficacy of Isola instrumentation and arthrodesis for adolescent idiopathic scoliosis: two- to 12-year follow-up

Socioeconomic differences in access to scoliosis care in the pediatric population

PURPOSE

Adolescent idiopathic scoliosis (AIS) is a common spinal deformity affecting pediatric patients, with up to 10% requiring surgical intervention. Studies have shown disparities in these patients associated with race, ethnicity, and insurance type, but there is limited information on disparities that exist based on geographical parameters. In this study, we aim to explore the disparities in the care for AIS by looking at differences in the rates of readmission, infection, and revision between patients residing in rural and urban environments.

METHODS

This is a retrospective cohort study utilizing the Pediatric Health Information System. Pediatric patients that underwent posterior spinal fusion (PSF) for AIS from October 2015 to July 2022 were included. Diagnoses and procedures were identified based on ICD-10 codes and internal tools built into the database. Descriptive statistics were used to summarize the data, including demographics, infection rates, readmission rates, and revision rates. T tests, Chi-squared tests, and logistic regression were used to assess differences between the rural and urban populations. We utilized STATA/SE 15.1 for all data analysis.

RESULTS

15,318 patients were included in the final cohort. Demographics and baseline characteristics were similar between the rural and urban patients, although more rural patients used Medicaid over commercial insurance (41.5% vs. 32.7%, p < 0.01), median household income was lower in rural patients (p < 0.01), and there was a higher proportion of Hispanic patients in the urban patient cohort (13.9% vs. 6.4%, p < 0.01). Complication rates were not significantly different between the urban and rural patient cohorts, although rural patients did have a significantly higher 90-day readmission rate (7.3% vs. 6.1%, p = 0.03) and higher rates of instrumentation removal (7.7% vs. 4.9%, p = 0.01).

CONCLUSIONS

The surgical outcomes between rural and urban pediatric AIS patients undergoing PSF are comparable, although 90-day readmission rates and rates of instrumentation removal were higher in rural patients. Insurance status is likely a significant driver for the differences observed in this study. Future research is needed to better understand the reasons for these differences and to develop strategies to improve outcomes.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Clinical role of crosslink augmentation during short-segment posterior lumbar interbody fusion with total facetectomy: A propensity score-matched analysis

We investigated the clinical role of crosslink augmentation during PLIF with total facetectomy. We retrospectively reviewed 376 patients who underwent one- or two-segment PLIF with unilateral or bilateral total facetectomy between January 2017 and March 2022. The patients were categorized into two groups based on whether a crosslink was instrumented or not. Radiological outcome measurements included fusion status and implant failure rates on 12-month postoperative computed tomography. Patient-reported outcome measures included the Numerical Rating Scale for lower back pain, Oswestry Disability Index, and Short Form-12 Physical Component Summary scores, which were assessed preoperatively and at 12 months postoperatively. Surgery-related complications included surgical site infection, symptomatic implant failure, and epidural hematoma. Propensity score matching was performed to compare both groups after adjusting for confounding factors, including baseline and surgical procedural characteristics. A total of 200 cases were included in the propensity score calculation, and one-to-one matching was performed, resulting in 56 pairs with and without a crosslink. The fusion status (88.7 % vs. 85.5 %), screw loosening (14.3 % vs. 14.3 %), cage subsidence (17.9 % vs. 16.1 %), and cage dislodgement (5.4 % vs. 0 %) showed no significant difference between those with and without a crosslink, respectively. No significant differences were observed in the patient-reported outcomes or surgery-related complication rates between the groups. Crosslink augmentation during PLIF with total facetectomy is not recommended because it does not provide any radiological or clinical benefit and is associated with avoidable expenses.

The machine-vision image guided surgery system reduces fluoroscopy time, ionizing radiation and intraoperative blood loss in posterior spinal fusion for scoliosis

PURPOSE

To determine if the novel 3D Machine-Vision Image Guided Surgery (MvIGS) (FLASH™) system can reduce intraoperative radiation exposure, while improving surgical outcomes when compared to 2D fluoroscopic navigation.

METHODS

Clinical and radiographic records of 128 patients (≤ 18 years of age) who underwent posterior spinal fusion (PSF), utilising either MvIGS or 2D fluoroscopy, for severe idiopathic scoliosis were retrospectively reviewed. Operative time was analysed using the cumulative sum (CUSUM) method to evaluate the learning curve for MvIGS.

RESULTS

Between 2017 and 2021, 64 patients underwent PSF using pedicle screws with 2D fluoroscopy and another 64 with the MvIGS. Age, gender, BMI, and scoliosis aetiology were comparable between the two groups. The CUSUM method estimated that the MvIGS learning curve with respect to operative time was 9 cases. This curve consisted of 2 phases: Phase 1 comprises the first 9 cases and Phase 2 the remaining 55 cases. Compared to 2D fluoroscopy, MvIGS reduced intraoperative fluoroscopy time, radiation exposure, estimated blood loss and length of stay by 53%, 62% 44%, and 21% respectively. Scoliosis curve correction was 4% higher in the MvIGS group, without any increase in operative time.

CONCLUSION

MvIGS for screw insertion in PSF contributed to a significant reduction in intraoperative radiation exposure and fluoroscopy time, as well as blood loss and length of stay. The real-time feedback and ability to visualize the pedicle in 3D with MvIGS enabled greater curve correction without increasing the operative time.

Is posteromedial translation with sublaminar bands effective in correcting axial rotation in adolescent idiopathic scoliosis surgery? A 3D reconstruction study

PURPOSE

Hybrid constructs with sublaminar bands have recently regained popularity as an alternative to all-screw construct for correction of adolescent idiopathic scoliosis (AIS). The aim of this study is to evaluate the ability of hybrid constructs with sublaminar bands to achieve a tridimensional correction of the scoliotic deformity. Our hypothesis is that hybrid construct with sublaminar bands are able to achieve a substantial derotation of the apical vertebrae, while preserving the thoracic kyphosis.

METHODS

A prospective evaluation of 50 consecutive cases (41 F, 9 M, mean age 14.7 ± 2 years) of AIS correction with hybrid construct was performed. In all cases, sublaminar bands were used at the apex of the main curve on concave side. All patients underwent pre and postoperative X-rays with EOS System, with full 3D reconstruction. Spinopelvic parameters and axial rotation of the vertebrae were measured pre and postoperatively.

RESULTS

2.7 ± 0.9 mean sublaminar bands were used per patient. Mean correction of deformity was 50 ± 9.5%. on the coronal plane. The mean axial rotation of the apical vertebra went from 18° ± 11.5° preoperatively to 9.4° ± 7.2° postoperatively (p < 0.001) with a mean derotation of 47.7%. Thoracic kyphosis went from 32.1° ± 18° preoperatively to 37.3° ± 13.1° postoperatively (p < 0.05). No intraoperative complications due to sublaminar bands were recorded.

CONCLUSIONS

Hybrid construct with sublaminar band have been showed to be safe and effective in deformity correction and in maintaining or restoring thoracic kyphosis. This study showed that with sublaminar bands applied at the curve apex a substantial derotation of the apical vertebrae can be achieved.

Very long-term clinical and radiographic outcomes after posterior spinal fusion with pedicular screws for thoracic adolescent idiopathic scoliosis

PURPOSE

To report radiographic and functional outcomes, with an average follow-up of 20 years, of adolescents treated surgically for thoracic idiopathic scoliosis by hybrid construct using only pedicular screws for the distal fixation.

METHODS

We retrospectively reviewed 109 patients. Radiographic data were evaluated on fullspine radiographs (Cobb angle, pelvic incidence, sacral slope, pelvic tilt, thoracic kyphosis, lumbar lordosis). Clinical data were evaluated with ODI, SF-12, SRS-30 and Analog Pain Scale. Disc height and listhesis below the arthrodesis were measured.

RESULTS

We analyzed 90 women and 19 men with a mean age of 16.9 y.o. at surgery. Radiographic data were assessed for 46 patients after 17.4 years. Mean preoperative Cobb angle was 58°, mean correction 40.1% with 5.3° of loss at final FU. Lumbar lordosis and thoracic kyphosis increased significantly at last FU. Degenerative changes below the arthrodesis were reported in 5 cases. Clinical data were assessed for 42 patients after 19.9 years: SRS-30 3.8; ODI 12.3%; SF-12 PCS 48.6 and MCS 46. Low back pain was reported in 69% of cases with low intensity (3.1). The lowest instrumented vertebrae did not influence significantly the functional outcome.

CONCLUSIONS

The correction of thoracic AIS with lumbar or thoracolumbar pedicle screw instrumentation provides good radiological and clinical outcomes at very long term. The reduction in the coronal plane is stable; the HRQoL is quite as good as the general population. The degenerative evolution below remain relatively rare, therefore global sagittal balance is not modified.

Effects of pre-contoured and in situ contoured rods on the mechanical strength and durability of posterior cervical instrumentation: a finite-element analysis and scanning electron microscopy investigation

STUDY DESIGN

Finite-element analysis.

OBJECTIVES

Intraoperative contouring of rods is a common procedure for spine surgeons to match the native curvature of the spine, but it may lead to premature weakening of the rod. This study investigated the effect of different bending methods on rod fatigue performance. Rod failure in the cervical spine is of clinical concern, particularly when spanning the cervicothoracic region and when considering corrective osteotomies for deformity correction and global spinal alignment.

METHODS

Finite-element models were developed to simulate rod bending (3.5 mm D, 40 mm L) to achieve a 23° angle with 3 different bending methods: French single, multiple bending, and in situ bending. Simulations were conducted in 4 steps: rod bending, rod spring back, residual stress relaxation, and F1717 mechanical test simulation.

RESULTS

French single bending resulted in the highest residual stress concentrations for both titanium (TiAlV) and cobalt chrome (CoCr) at 783 MPa and 507 MPa, respectively. During F1717 test simulation, the French single bent rod had its highest tensile stress in the middle, with 917 MPa and 623 MPa, respectively, for TiAlV and CoCr, compared to in situ (580 MPa and 586 MPa for TiAlV and CoCr) and the French multiple bent rod (765 MPa and 619 MPa for TiAlV and CoCr). The computational model found that CoCr rods made the construct least prone to deformation.

CONCLUSIONS

French single bend with TiAlV rods put the construct at highest risk of failure. CoCr rods led to minimal physical changes in microstructure while showing evidence of flattening.

Surgeon volume affects short- and long-term surgical outcomes in idiopathic scoliosis

STUDY DESIGN

Retrospective review of New York Statewide Planning and Research Cooperative System (SPARCS) Inpatient Database.

OBJECTIVE

To identify the differences in short- and long-term complications, following long-segment pediatric spinal fusion in idiopathic scoliosis surgery, between surgeons with low versus high annual surgical volume. Spinal deformity surgery is complex and requires significant training and repetition to master. Surgeon and hospital volume have been shown to correlate with outcomes following cervical and lumbar spine surgery. However, there is limited literature regarding the impact of surgeon volume on long-term outcomes following pediatric idiopathic spinal deformity correction.

METHODS

This is a retrospective review of the SPARCS inpatient database from 2004 to 2013 of pediatric patients who underwent idiopathic scoliosis surgery. Surgeons were stratified into high (> 15 cases/year)- and low (≤ 15 cases/year)-volume cohorts by aggregating all cases completed over the study period until 50% of the total cases were captured above and below an average case per-year threshold. This threshold occurred at 15 cases/year. Short-term and long-term readmission and medical/surgical complications were collected. Multivariate logistic regression models assessed the risk of short- and long-term complications between cohorts.

RESULTS

3910 pediatric patients underwent a primary arthrodesis from a total of 223 surgeons. More high-volume surgeons operated at academic teaching hospitals (p < 0.001), used a combined AP surgical approach (p < 0.001), and fewer utilized rhBMP (p < 0.001). High-volume surgeons had shorter lengths of stay (p < 0.001). Low-volume surgeons had increased odds of inpatient surgical complications (OR 1.55, 95% CI 1.00-2.45). Low-volume surgeons had increased odds of revision at 5 and 10 years (5 years. OR 1.56, 95% CI 1.05-2.31; 10 years. OR 1.59, 95% CI 1.09-2.31). Low-volume surgeons had increased odds of implant malfunction at 10 years (OR 1.81, 95% CI 1.15-2.86).

CONCLUSIONS

High-volume surgeons had decreased odds of short- and long-term complications compared to low volume when performing primary spinal arthrodesis in idiopathic scoliosis. Low-volume surgeons experienced significantly greater odds of inpatient surgical complications, as well as increased risk of revision during long-term follow-up with a significantly increased risk of implant malfunction at 10 years post-operatively.

LEVEL OF EVIDENCE

Level III.

Effects of transverse connector on reduction and fixation of atlantoaxial dislocation and basilar invagination using posterior C1-C2 screw-rod technique

BACKGROUND CONTEXT

The mechanical strength provided by internal fixation is crucial for maintaining reduction and facilitating bony fusion. Though satisfactory results with the C1-C2 technique have been acquired in most clinical reports, the related problems of fusion delay and pseudarthrosis still exist. To increase the chance of bony fusion, a transverse connector (TC) is frequently used to augment torsional stiffness of thoracolumbar screw/rod constructs. Nevertheless, the clinical implication of TC in the management of atlantoaxial dislocation (AAD) and basilar invagination (BI) remains largely unknown.

PURPOSE

To evaluate the effects of TC application on C1-C2 screw-rod constructs based on consecutive adult patients with AAD and BI in a single institution over a 10-year period.

STUDY DESIGN

A retrospective study.

PATIENT SAMPLE

Patients with AAD and BI, who were treated with posterior C1-C2 screw-rod technique with or without TC usage from June 2007 to June 2017 at a single institution.

OUTCOME MEASURES

The radiological measurements included the anterior atlantodental interval (AADI), posterior atlantodental interval (PADI), height of odontoid process above Chamberlain line, and cervicomedullary angle (CMA). Patients' neurologic status was evaluated with the Japanese Orthopaedic Association (JOA) score. Fusion status was evaluated at different follow-up periods.

METHODS

We compared the difference of clinical, radiological, and surgical outcomes between the TC and NTC groups postoperatively.

RESULTS

In total, there were 149 consecutive patients in the TC group and 168 patients in the NTC group. On average, 1.2 TCs per patient were used in the TC group. No significant differences were identified for operative time and blood loss between groups. There was also no statistical difference in the radiological measurements of AADI, PADI, Chamberlain line, and CMA between the TC and NTC groups preoperatively and postoperatively. A significantly higher JOA score was obtained in the TC group than that in the NTC group postoperatively. The fusion rates were higher in the TC group than those in the NCT group at the early stage postoperatively (3 and 6 months; p<.01).

CONCLUSIONS

Use of TCs seems to improve bony fusion and neurologic outcomes in the treatment of AAD and BI with C1-C2 screw-rod technique.

The Role of Cross-Links in Posterior Spinal Fusion for Cerebral Palsy-Related Scoliosis

STUDY DESIGN

Retrospective review of a multicenter, prospective database.

OBJECTIVE

Our aim was to compare complication rates and maintenance of radiographic correction at 2 years after posterior spinal fusion (PSF) with or without cross-links in patients with cerebral palsy (CP)-related scoliosis.

SUMMARY OF BACKGROUND DATA

Cross-links are frequently used in PSF to correct scoliosis in patients with CP because they are thought to increase the stiffness and torsional rigidity of the construct.

METHODS

We reviewed the records of patients with CP who underwent primary PSF with or without cross-links between August 2008 and April 2015. Inclusion criteria were minimum follow-up of 2 years, availability of complications data (implant failure, surgical site infection, revision), and pre- and postoperative measurements of the major curve (measured using the Cobb method). The 256 patients included in this analysis had a mean age of 14.1 ± 2.7 years. Ninety-four patients had cross-links (57% using one cross-link; 43% using two cross-links) and 162 patients did not have cross-links. P < 0.05 was considered statistically significant.

RESULTS

The two groups did not differ significantly with regard to sex, age at surgery, preoperative menarche status, Gross Motor Function Classification System level, major curve magnitude, pelvic obliquity, kyphosis, and lordosis angles. There were no significant differences between groups in the correction achieved or the maintenance of correction at 2 years for the major curve, pelvic obliquity, kyphosis, or lordosis (all P > 0.05). Complication rates were similar between the cross-link group (16%, N = 15) and the non-cross-link group (14%, N = 22).

CONCLUSION

At 2 years after PSF to treat CP-related scoliosis, patients had no significant differences in the degree of correction achieved, the maintenance of correction, or the rate of complications between those whose fusion constructs used cross-links and those whose constructs did not.

LEVEL OF EVIDENCE

3.

Correction of thoracic adolescent idiopathic scoliosis via a direct convex rod manoeuvre

The various techniques available for scoliosis surgery via the posterior approach involve positioning implants on either side of the curve and reducing the deformity by manoeuvres on the concave rod or simultaneously on both rods. Correction solely via a direct convex rod manoeuvre would eliminate the need for implants on the concave side. This technique was used to treat thoracic adolescent idiopathic scoliosis in 23 patients with a mean age of 14 years and 9 months. Low-dose biplanar EOS radiographs were obtained before surgery, on post-operative day 7, and at last follow-up (at least 2 years after surgery) to allow comparisons of Cobb's angle (72°, 33°, and 35°, respectively), thoracic kyphosis (21°, 29°, and 26°), lumbar lordosis (58°, 50°, and 55°), and apical vertebra rotation (-26°,-12°, and-11°). Although scoliosis requires corrections in all three dimensions, this technique seems to produce satisfactory outcomes while obviating the need for implants on the concave side, thereby decreasing the risk of iatrogenic adverse events. LEVEL OF EVIDENCE: IV.

Incidence of complete spinal instrumentation removal following surgery for spinal deformity: a 22-year single institution study

The aim of this study was to define the incidence of complete implant removal following surgical correction of spinal deformity in pediatric patients over a 22-year period and identify possible risk factors. A retrospective review of our Pediatric Orthopedic Spine Database between 1992 and 2016 was performed. We included patients undergoing complete implant removal following scoliosis correction surgery with a minimum of 2-year follow-up. Medical charts were reviewed to determine initial patient diagnosis and the indication for implant removal. Statistical analysis was carried out to determine the associations between sex and factors such as primary diagnosis and indication for removal. A review of 1117 procedures in 1114 patients identified complete instrument removal in 52 (4.7%) patients (34 females and 18 males). Mean time to removal following surgery was 2.3 years (range: 0-5.9 years). Removal occurred in 24 of 548 (4.4%) patients with adolescent idiopathic scoliosis, four of 117 (3.4%) patients with juvenile idiopathic scoliosis, 11 of 287 (3.8%) patients with neuromuscular scoliosis, and three of 79 (3.8%) patients with syndromic scoliosis. Infection was the most common indication for complete implant removal [24 (46%) patients], followed by persistent pain [8 (15%) patients], and metal intolerance [8 (15%) patients]. There were two cases of early infection (<1 year following surgery) and 22 late infections (≥1 year following surgery). The overall 22-year incidence of complete implant removal following spinal correction surgery for scoliosis was 4.7%. Infection continues to be the most common indication, followed by pain and metal intolerance.

Secondary Surgery Rates After Primary Fusion for Adolescent Idiopathic Scoliosis

Instrumented spinal fusion is the gold standard treatment for surgical magnitude adolescent idiopathic scoliosis (AIS), with the goal being stable fusion without the need for additional procedures. The purpose of this study was to define the surgical return rates of AIS at a single center with respect to various instrumentation constructs used during initial spinal fusion. A retrospective chart review was performed of all patients with AIS who underwent instrumented fusion with a minimum of 2-year follow-up. Demographic information, implant type, and surgical approach for the primary surgery and all subsequent secondary operations were recorded. Four hundred eleven patients who underwent instrumented fusion for AIS during the study period met inclusion criteria. Sixty-six secondary operations were performed in 50 patients (12.2%). Symptomatic hardware, pseudarthrosis, and infection were the most common indications for secondary surgery. Posterior pedicle screw constructs had a lower secondary surgery rate (5.8%) compared with hybrid and combined fusions (P<.05). The all hook, hybrid, anterior only, and combined fusions had secondary surgery rates of 13.0%, 18.5%, 10.0%, and 20.8%, respectively, which were not statistically different. When specifically comparing pedicle screw with hook constructs, there was a statistically lower pseudarthrosis rate (P=.03) favoring pedicle screw instrumentation. Patients undergoing instrumented fusion for AIS are at some risk for subsequent surgery. To lessen that risk, pedicle screw constructs should be considered, as they have shown an overall lower secondary surgery rate and in particular a lower rate of pseudarthrosis. [Orthopedics. 2019; 42(4):235-239.].

The Ecuador Pediatric Spine Deformity Surgery Program: An SRS-GOP Site, 2008-2016

STUDY DESIGN

Retrospective case series.

OBJECTIVES

The purpose of this study is to (1) describe the development of our Spinal Deformity Program; (2) assess the surgical outcomes, including health-related quality of life (HRQOL), radiographic measures, and complications; and (3) explore predictors for HRQOL outcomes.

SUMMARY OF BACKGROUND DATA

The Scoliosis Research Society (SRS) is very interested in international program site development to provide safe surgical care for children in low- and middle-income countries (LMICs). There is a need for reporting program development and outcomes from these sites. After several years of building local relations and infrastructure, our program started performing spine surgery in 2008.

METHODS

All operations were performed at Roberto Gilbert Elizalde Children's Hospital in Guayaquil, Ecuador. At a minimum of two years and average of four years postoperatively, patients received a clinical evaluation, radiographs, and the Spanish SRS-22r questionnaire.

RESULTS

Twenty-eight (74%) of the 38 children who received spine surgery between May 2008 and 2015 are included in this study. Twenty-three (82%) were female with an average age of 14 years at the time of surgery and 18 years at follow-up. The mean total SRS-22r score was 4.3 and mean percentage major curve correction was 57%. Curve location was found to be a significant predictor of postoperative SRS-22r scores with double curves having poorer scores (p = .004). Two complications were pseudarthrosis and postoperative delayed paraplegia, both of which resolved after revision surgery. No infections or other long-term complications have occurred.

CONCLUSIONS

The development of equitable surgical care for all children is a primary goal of the SRS. Undertaking the task to perform surgery in LMIC comes with the responsibility to monitor and maintain the highest quality. Our program was safely developed to address the surgical needs of children with good midterm HRQOL outcomes, adequate radiographic curve correction, and no permanent complications.

LEVEL OF EVIDENCE

Level IV.

How to Optimize Axial Correction Without Altering Thoracic Sagittal Alignment in Hybrid Constructs With Sublaminar Bands: Description of the "Frame" Technique

STUDY DESIGN

Retrospective monocentric database study.

OBJECTIVES

To describe the "frame" reduction technique and report the 3D quantitative analysis of postoperative corrections in a consecutive series of thoracic adolescent idiopathic scoliosis (AIS) patients.

SUMMARY OF BACKGROUND DATA

Posteromedial translation technique using sublaminar bands have been proved to be efficient and safe for 3D correction of the deformity and overall cosmetic aspect of the trunk. However, the ability to correct the axial plane may tend to rotate the vertebra clockwise instead of counterclockwise, thus increasing apical vertebra axial rotation (AVR) and the rib hump. A technical improvement was developed to emphasize axial correction.

METHODS

60 thoracic AIS patients consecutively operated by posteromedial translation using the "frame" reduction technique were included with a minimum 2-year follow-up. Precontoured rods were connected with fixed transverse connectors according to a personalized preoperative planning. Rods were first inserted distally in the pedicle screws to achieve lumbar correction, and then in the upper anchors, and finally sublaminar bands were connected to their corresponding rods to progressively bring the concave lamina to the concave rod to correct the thoracic deformity. Sagittal and coronal 3D measures were performed preoperatively and at the latest follow-up using SterEOS (EOS Imaging, Paris, France) to assess the efficiency of the technique.

RESULTS

The distance from the center of the apical vertebra to the reference axis in the frontal plane was reduced from 4.7 to 1.1 cm, traducing the efficient medial translation of the spine during correction. T1-T12 kyphosis significantly increased after surgery (28°-35°). 3D location of the upper instrumented vertebra (UIV) was not affected. The apical rotation was significantly reduced after surgery (19°-11°), and the AVR correction rate averaged 42.2%.

CONCLUSION

The "frame" technique is an innovative way of using polyester bands, optimizing axial correction while respecting sagittal alignment.

LEVEL OF EVIDENCE

Level IV.

Spinal instrumentation in infants, children, and adolescents: a review

OBJECTIVEThe evolution of pediatric spinal instrumentation has progressed in the last 70 years since the popularization of the Harrington rod showing the feasibility of placing spinal instrumentation into the pediatric spine. Although lacking in pediatric-specific spinal instrumentation, when possible, adult instrumentation techniques and tools have been adapted for the pediatric spine. A new generation of pediatric neurosurgeons with interest in complex spine disorder has pushed the field forward, while keeping the special nuances of the growing immature spine in mind. The authors sought to review their own experience with various types of spinal instrumentation in the pediatric spine and document the state of the art for pediatric spine surgery.METHODSThe authors retrospectively reviewed patients in their practice who underwent complex spine surgery. Patient demographics, operative data, and perioperative complications were recorded. At the same time, the authors surveyed the literature for spinal instrumentation techniques that have been utilized in the pediatric spine. The authors chronicle the past and present of pediatric spinal instrumentation, and speculate about its future.RESULTSThe medical records of the first 361 patients who underwent 384 procedures involving spinal instrumentation from July 1, 2007, to May 31, 2018, were analyzed. The mean age at surgery was 12 years and 6 months (range 3 months to 21 years and 4 months). The types of spinal instrumentation utilized included occipital screws (94 cases); C1 lateral mass screws (115 cases); C2 pars/translaminar screws (143 cases); subaxial cervical lateral mass screws (95 cases); thoracic and lumbar spine traditional-trajectory and cortical-trajectory pedicle screws (234 cases); thoracic and lumbar sublaminar, subtransverse, and subcostal polyester bands (65 cases); S1 pedicle screws (103 cases); and S2 alar-iliac/iliac screws (56 cases). Complications related to spinal instrumentation included hardware-related skin breakdown (1.8%), infection (1.8%), proximal junctional kyphosis (1.0%), pseudarthroses (1.0%), screw malpositioning (0.5%), CSF leak (0.5%), hardware failure (0.5%), graft migration (0.3%), nerve root injury (0.3%), and vertebral artery injury (0.3%).CONCLUSIONSPediatric neurosurgeons with an interest in complex spine disorders in children should develop a comprehensive armamentarium of safe techniques for placing rigid and nonrigid spinal instrumentation even in the smallest of children, with low complication rates. The authors' review provides some benchmarks and outcomes for comparison, and furnishes a historical perspective of the past and future of pediatric spine surgery.

Cobalt-chrome and titanium alloy rods provide similar coronal and sagittal correction in adolescent idiopathic scoliosis

BACKGROUND

Cobalt-chrome (CoCr) and the titanium alloy TA6V (Ti) are the materials most widely used for spinal instrumentations in patients with adolescent idiopathic scoliosis (AIS). The objective of this work was to compare the effectiveness of CoCr and Ti rods in terms of coronal and sagittal correction by pedicle screw constructs in patients with AIS.

HYPOTHESIS

Correction is similar with CoCr and Ti rods in patients with AIS.

MATERIAL AND METHOD

A retrospective single surgeon study was conducted in patients with AIS managed using pedicle screw posterior spinal fusion with high implant density and reduction by postero-medial translation. Follow-up was more than 2 years in all patients. Patients were divided into two groups based on whether the rods used were made of CoCr (n=30) or Ti (n=33). The groups were identical for age, Risser classification, follow-up duration, type of curve, and implant density. Coronal and sagittal parameters on standing full-spine radiographs were analysed using graphics software before surgery then 1 month after surgery and at last follow-up. Quantitative data were compared by applying Student's t test.

RESULTS

The percentage of main curve correction at last follow-up was the same in the two groups (76%/75%) (p=0.7). Gains in thoracic kyphosis (12°/13°) and lumbar lordosis (8°/10°) were not significantly different between groups. At last follow-up, 3 patients had proximal junctional kyphosis, 1 in the CoCr group and 2 in the Ti group (p=0.6).

CONCLUSION

For posterior spinal fusion to treat AIS, with a high density of pedicle screws, correction by translation, and 6 mm rods, CoCr rods and Ti rods produce the same amount of coronal and sagittal correction.

LEVEL OF EVIDENCE

IV, comparative retrospective study with no control group.

Pseudarthrosis in adult and pediatric spinal deformity surgery: a systematic review of the literature and meta-analysis of incidence, characteristics, and risk factors

We conducted a systematic review with meta-analysis and qualitative synthesis. This study aims to characterize pseudarthrosis after long-segment fusion in spinal deformity by identifying incidence rates by etiology, risk factors for its development, and common features. Pseudarthrosis can be a painful and debilitating complication of spinal fusion that may require reoperation. It is poorly characterized in the setting of spinal deformity. The MEDLINE, EMBASE, and Cochrane databases were searched for clinical research including spinal deformity patients treated with long-segment fusions reporting pseudarthrosis as a complication. Meta-analysis was performed on etiologic subsets of the studies to calculate incidence rates for pseudarthrosis. Qualitative synthesis was performed to identify characteristics of and risk factors for pseudarthrosis. The review found 162 articles reporting outcomes for 16,938 patients which met inclusion criteria. In general, the included studies were of medium to low quality according to recommended reporting standards and study design. Meta-analysis calculated an incidence of 1.4% (95% CI 0.9-1.8%) for pseudarthrosis in adolescent idiopathic scoliosis, 2.2% (95% CI 1.3-3.2%) in neuromuscular scoliosis, and 6.3% (95% CI 4.3-8.2%) in adult spinal deformity. Risk factors for pseudarthrosis include age over 55, construct length greater than 12 segments, smoking, thoracolumbar kyphosis greater than 20°, and fusion to the sacrum. Choice of graft material, pre-operative coronal alignment, post-operative analgesics, and sex have no significant impact on fusion rates. Older patients with greater deformity requiring more extensive instrumentation are at higher risk for pseudarthrosis. Overall incidence of pseudarthrosis requiring reoperation is low in adult populations and very low in adolescent populations.

Preventing Distal Junctional Kyphosis by Applying the Stable Sagittal Vertebra Concept to Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Multicenter retrospective review.

OBJECTIVE

To assess the effectiveness of using the stable sagittal vertebra (SSV) for selecting the lowest instrumented vertebrae (LIV) to prevent distal junctional kyphosis (DJK) in selective thoracic fusions.

SUMMARY OF BACKGROUND DATA

Cho et al. reported that including the SSV in a fusion decreased the rate of DJK in thoracic hyperkyphosis.

METHODS

A retrospective review was performed of patients from two pediatric hospitals with adolescent idiopathic scoliosis who underwent selective posterior thoracic fusion with the LIV at L2 or above from 2000 to 2012. Patients with less than 2 years' follow-up were excluded. The primary outcome measure was DJK, defined radiographically as ≥10° between the superior end plate of the LIV and the inferior end plate of the vertebra below on a standing lateral radiograph. We investigated the SSV, which was defined as the vertebral level at which 50% of the vertebral body was in front of the posterior sacral vertical line (PSVL) on a standing lateral radiograph. This particular definition was referred to as SSV.

RESULTS

A total of 113 patients met the inclusion criteria. Mean age was 14.4 years. Mean Cobb angle was 58°. The overall rate of DJK was 7% (8/113). When the LIV was superior to SSV, the rate of DJK was 17% (8/46) versus 0% (0/67) when the LIV was at or inferior to SSV (p=.01). The rates of DJK for patients with the LIV one, two, and three levels above SSV were 17% (4/24), 7% (1/14), and 43% (3/7), respectively. There was no significant association between preoperative or postoperative maximum kyphosis, thoracic kyphosis, thoracolumbar kyphosis, pelvic incidence, sagittal balance or coronal balance, and development of DJK.

CONCLUSION

Although LIV selection is complex, choosing the LIV at or below the SSV is a simple rule that minimizes the risk of DJK.

LEVEL OF EVIDENCE

Level IV.

SRS-22r Scores in Nonoperated Adolescent Idiopathic Scoliosis Patients With Curves Greater Than Forty Degrees

STUDY DESIGN

Case control comparative series.

OBJECTIVE

Describe surgical range adolescent idiopathic scoliosis (AIS) patients electing to forgo surgery and compare health-related quality-of-life outcomes to a similar cohort of operated AIS patients by the same single surgeon.

SUMMARY OF BACKGROUND DATA

No data have been published either documenting SRS-22r scores of nonoperated patients with curves ≥40° or comparing these scores to a demographically similar operated cohort.

METHODS

Individuals with curves ≥40°, age ≥18 years, and electing to forgo surgery were identified. All patients completed an SRS-22r questionnaire. This nonoperated cohort's SRS-22r scores were compared to those of a large demographically similar cohort operated by the same surgeon. Group differences between the SRS-22r scores were evaluated by comparing these to published Minimal Clinically Important Differences (MCID) for the SRS-22r.

RESULTS

One hundred ninety subjects with nonoperated curves were compared to 166 individuals who underwent surgery. The nonoperated cohort averaged 23.5 years of age, averaged 7.7 years since curve reached 40°, and had an average 50° Cobb angle at last follow-up. No statistical significant differences were found between the groups on the Pain, Function, or Mental Health domains of the SRS-22r. Statistically significant differences in favor of the operative cohort were found for self-image, satisfaction, and total score. The observed group differences did not meet the established thresholds for minimal clinically important differences in any of the domain scores, the average total score, or raw scores.

CONCLUSION

There are no meaningful clinically significant differences in SRS-22r scores at average 8-year follow-up between AIS patients with curves ≥40° treated with or without surgery. These data in conjunction with an absence of long-term evidence of serious medical consequences with nonsurgical management of curves ≥40° should encourage surgeons to reevaluate the benefits of routine surgical care.

LEVEL OF EVIDENCE

3.

Perioperative and Delayed Major Complications Following Surgical Treatment of Adolescent Idiopathic Scoliosis

BACKGROUND

Reporting accurate surgical complication rates to patients and their families is important in the management of adolescent idiopathic scoliosis (AIS). In this study, we report the rate of major complications following the surgical treatment of AIS both in the perioperative period and among patients with a minimum of 2 years of follow-up.

METHODS

We reviewed the prospectively collected data of a multicenter registry of patients who underwent surgical treatment of AIS during the period of 1995 to 2014 in order to identify all complications. A complication was defined as "major" if it resulted in reoperation or in spinal cord or nerve root injury, or was life-threatening. A total of 3,582 patients with preoperative and early postoperative data (4 to 6 weeks of follow-up) were included. A subset of 2,220 patients with a minimum of 2 years of follow-up comprised the cohort for delayed complications. Overall complication rates were calculated, as was the percentage of complications according to the year of the index surgery and type of surgical approach.

RESULTS

The mean age of the 3,582 patients at the time of surgery was 14.8 ± 2.2 years. The average major curve magnitude was 56° ± 13° for thoracic curves and 51° ± 11° for lumbar. In 365 patients, anterior spinal fusion (ASF) with instrumentation was performed, and in 3,217 patients, posterior spinal fusion (PSF) with instrumentation was performed; 142 patients in the PSF group underwent concomitant anterior release. There were 192 major complications, with 93 (2.6%) occurring perioperatively. Perioperative complications included wound-related (1.0% of the patients), neurologic (0.5%), pulmonary (0.4%), instrumentation-related (0.4%), and gastrointestinal (0.2%) complications. One patient died. The mean annual perioperative major complication rate based on the year of surgery ranged from 0% to 10.5%. The complication rate by surgical approach was 3.0% for ASF and 2.6% for PSF (2.4% for PSF only and 5.6% for PSF with anterior release). The major complication rate for the 2,220 patients with at least 2 years of follow-up was 4.1%; all but 1 had a reoperation (4.1%). The majority of these major complications were wound and instrumentation-related (1.9% and 0.8%, respectively).

CONCLUSIONS

After surgery for AIS, a 2.6% rate of perioperative major complications and a 4.1% rate of major complications at 2 or more years after surgery can be anticipated. The complication rate decreased over the period of study.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

5-Year Reoperation Risk and Causes for Revision After Idiopathic Scoliosis Surgery

STUDY DESIGN

An actuarial "survivorship" analysis.

OBJECTIVE

The aim of this study was to define the incidence and cause of surgical revision 5 years after scoliosis surgery.

SUMMARY OF BACKGROUND DATA

Data on contemporary revision surgery rates after idiopathic scoliosis surgery beyond the 2 years postoperatively in the adolescent and young adult population are limited.

METHODS

Patients enrolled in a prospective, multicenter, idiopathic scoliosis surgical registry from 1995 to 2009 were reviewed. Any spine reoperation was defined as a "terminal event." An actuarial survivorship analysis that adjusts for patients lost to follow-up was performed to determine cumulative survival. Time intervals were defined as 0 to <3 months, 3 months to <1 year, 1 to <2 years, 2 to <5 years, and 5 to 10 years. Registry data and radiographs were reviewed and five categories for reoperation assigned: 1) implant failure and/or pseudarthrosis, 2) implant misplacement and/or prominence, 3) wound complication and/or infection, 4) residual deformity and/or progression, and 5) other.

RESULTS

One thousand four hundred thirty-five patients from 12 sites were included. The majority were female (80%), with major thoracic curves (76% Lenke 1-4), and average age of 15 ± 2 years (10-22) at surgery. Most had posterior spinal instrumentation and fusion (81%). At this time, 75 (5.2%) patients required reoperation. Twenty-two occurred within 3 months postop, 10 more before 1 year, 12 more before 2 years, another 20 by 5 years, and 10 more after 5 years. This corresponded to an actuarial cumulative survival of 98.3% at 3 months, 97.5% at 1 year, 96.6% at 2 years, 93.9% at 5 years, and 89.8% at the final interval (5-10 yrs).

CONCLUSION

Revisions for scoliosis continue to occur well after 2 years with a 5-year survivorship of 93.9%. Reasons for reoperation are not uniformly distributed over time, with implant-related issues and infection the leading cause for early revision, while late infection was the most common cause after 2 years. Long-term follow-up of these postoperative patients remains important.

LEVEL OF EVIDENCE

3.

Selective Anterior Thoracolumbar Fusion in Adolescent Idiopathic Scoliosis: Long-Term Results After 17-Year Follow-Up

STUDY DESIGN

Prospectively updated long-term data and retrospective case series analysis.

OBJECTIVE

To report the long-term results of selective anterior instrumented thoracolumbar (ThL) fusion in adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The results of anterior selective fusion in AIS have been reported up to 2 and 5 years follow-up. However, there is a lack of evidence of long-term results of this surgical approach.

METHODS

Forty-two consecutive patients with main thoracolumbar/lumbar AIS who had undergone surgery for a selective anterior ThL instrumented fusion with more than 12 years of follow-up met inclusion criteria. Preoperative, postoperative (1-yr), and final updated radiographic parameters were recorded. Final ODI and SRS-22 questionnaires were evaluated.

RESULTS

Thirty-five patients were finally recruited (5 were lost and 2 refused). The mean age at surgery was 16.6 years. The mean final follow-up was 17.3 years (12-24 yr).The ThL preoperative Cobb was 49.5° ± 9, obtaining a postoperative correction of 79%±13 and final correction of 72% ± 18. The preoperative thoracic curve (31.4° ± 14.2) obtained a spontaneous postoperative correction to 18.4° ± 11.9, maintained at final follow-up (17.8° ± 10.8). Apical vertebral rotation improved from 25.8° ± 7.8 to 9.2° ± 5.5 and finally to 8° ± 5.2 (P = 0.001). Sagittal parameters (T5-T12 = 27.2° and L1-S1=56.9°) did not change significantly postoperatively nor by final follow-up. Coronal balance improved from 2.4 cm to 1.6 cm postoperatively and 0.8 cm at final follow-up (P = 0.006). The disc angulation below the last instrumented vertebra improved with follow-up from 7.6° to 5.7° (P = 0.012).There were no revision surgeries or infections. One patient showed a symptomatic lower disc degeneration requiring lumbar pain surgery. Final SRS-22 global score was 4.3/5. The final ODI scored 6/100.

CONCLUSION

In the long term, selective anterior thoracolumbar instrumentation with a single solid rod in AIS maintained good corrections on the three planes with no major complications or infections, no revision surgeries, and with satisfactory final functional and clinical outcomes.

LEVEL OF EVIDENCE

4.

Multiple concave rib head resection improved correction rate of posterior spine fusion in treatment of adolescent idiopathic scoliosis

BACKGROUND

Hybrid constructs have been widely used to surgically correct thoracic adolescent idiopathic scoliosis (AIS). To enhance the correction obtained with hybrid constructs, we perform concave rib head resection and convex costovertebral release as posterior release procedures. The objective of the study was to evaluate coronal and sagittal curve correction in patients with adolescent idiopathic scoliosis (AIS) treated with hybrid constructs combined with concave rib head resection and convex transverse process resection as posterior release procedures.

METHODS

The records of 24 patients with Lenke type 1 or 2 AIS treated with hybrid constructs combined with posterior release procedures were retrospectively reviewed. The mean age at surgery was 14.3 years. The mean follow-up period was 33.0 months (range, 24-60 months). Radiographs were evaluated before surgery, immediately postoperatively, and at latest follow-up.

RESULTS

The average preoperative Cobb angle of the main thoracic (MT) curve was 58.1 ± 12.6° (range, 45-88°). The MT curve was corrected to 12.8 ± 9.0° (range, 0-38°) immediately after surgery. At the latest follow-up, the average Cobb angle was 13.6 ± 9.9° (range, 0-44°; correction, 77.5 ± 14.0%). The average loss of coronal correction was 0.8°. The average preoperative flexibility of the MT curve was 54.6 ± 17.4%. The average Cincinnati correction index was 1.53 ± 0.48 at the latest follow-up. The average preoperative thoracic kyphosis (TK) was 13.7 ± 12.0° (range, -12-34°). Immediately after surgery, TK was corrected to 18.6 ± 5.9° (range, 10-29°). At the latest follow-up, TK measured 18.1 ± 6.5° (range, 6-32°).

CONCLUSIONS

Hybrid instrumentation combined with concave rib head resection and convex transverse process resection as posterior release procedures achieved satisfactory coronal and sagittal curve correction with little loss of correction at 2-year follow-up.

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

INTRODUCTION

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.

METHODS

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.

RESULTS

(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°.

CONCLUSIONS

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.

Posterior Vertebral Column Resection for Severe and Rigid Spinal Deformity Associated With Neurological Deficit After Implant Removal Following Posterior Instrumented Fusion: A Case Report and Literature Review

STUDY DESIGN

Case report.

OBJECTIVE

To investigate the safety and efficacy of posterior vertebral column resection for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion.

SUMMARY OF BACKGROUND DATA

Loss of correction after implant removal in patients with posterior instrumented fusion has been previously reported. However, to our knowledge, posterior vertebral column resection (PVCR) for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion has not been reported.

METHODS

An 18-year-old female with severe and rigid spinal deformity associated with neurological deficit was classified as Frankel C, according to the Frankel grading system. She underwent posterior spinal fusion with pedicle screw fixation at 16 years, and her implants were removed after 1 year due to back pain. Seven months after removal of the implants, she began to experience weakness in her lower limbs but did not seek any treatment. She was unable to stand and had to use a wheelchair. The patient successfully underwent PVCR and posterior reinstrumentation. Within 3 months, her neurological status improved to Frankel E.

RESULTS

The patient had no neurological deterioration and infections. There was no instrumentation failure and loosening correction at the 32 months follow-up.

CONCLUSION

Our results suggest that PVCR and pedicle screw fixation is a safe and efficacious option for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion.

LEVEL OF EVIDENCE

N/A.

Cross-Links Do Not Improve Clinical or Radiographic Outcomes of Posterior Spinal Fusion With Pedicle Screws in Adolescent Idiopathic Scoliosis: A Multicenter Cohort Study

STUDY DESIGN

Retrospective, comparative analysis.

OBJECTIVES

Comparative analysis was performed to determine the differences, if any, between adolescent idiopathic scoliosis (AIS) patients who underwent posterior spinal fusion (PSF) with and without cross-links.

SUMMARY OF BACKGROUND DATA

Cross-links are frequently used during PSF for AIS. It is unclear whether they provide any advantage for patients with all-pedicle screw constructs.

METHODS

A prospectively collected multicenter database of patients with AIS undergoing spinal fusion was retrospectively queried. Study inclusion criteria were primary PSF with all-pedicle screw fixation (greater than 90% fixation points) and minimum 2 years' follow-up. Collected data included demographics, radiographic measures, complications, Scoliosis Research Society-22r and Spinal Appearance Questionnaire (SAQ) scores.

RESULTS

A total of 500 patients were included (377 cross-link and 123 non-cross-link). Age, body mass index, gender, and preoperative major Cobb angle were not different between groups. Except for a slightly decreased lumbar Cobb angle (2.7°) in the cross-link group, no other radiographic measures were different at follow-up. Complications were not significantly different between groups: 21 of 377 (6%) crosslink and 9 of 123 (7%) non-cross-link. Infection occurred in 1 patient in the cross-link group and none in the non-cross link group. Reoperation occurred in 4 patients, all with cross-links (3 for implant removal and 1 for distal adding-on). Scoliosis Research Society-22r scores, total and individual domains, improved by a similar amount in both groups. At follow-up, parent and patient SAQ appearance scores were not significantly different. The SAQ expectations domain scores were similar for all visits and improved for both patients and parents.

CONCLUSIONS

There do not appear to be significant clinical or radiographic outcome differences in patients with AIS undergoing PSF based on the use of cross-links at 2-year follow-up. Surgeons should consider eliminating cross-links in patients with AIS who have PSF with all-pedicle screw constructs. This may have substantial cost savings without affecting patient outcome.

Congenital scoliosis SRS-22 outcomes in children treated with observation, surgery, and VEPTR

STUDY DESIGN

Prospective, nonrandomized study of children with congenital scoliosis.

OBJECTIVE

To determine the outcomes of children with congenital scoliosis using SRS-22.

SUMMARY OF BACKGROUND DATA

Outcome measures in children with congenital scoliosis are unreported. Novel treatments such as VEPTR (vertical expandable prosthetic titanium rib) must show positive patient-reported outcomes during treatment because improvement in pulmonary function has not been demonstrated.

METHODS

Patients with congenital scoliosis were prospectively enrolled and divided into 3 groups: children under observation (OBSERVATION), children who had surgery (SURGICAL), and children treated with VEPTR (VEPTR). The SRS-22 questionnaire reports 6 domains: Total, Function, Mental Health, Image, Satisfaction, and Pain. SRS-22 questionnaires were prospectively collected from 184 OBSERVATION patients, 27 SURGICAL patients, and 22 VEPTR patients. Because of repeated measurement on each patient, the observations cannot be assumed to be independent. To account for this dependence, linear mixed models were used.

RESULTS

OBSERVATION scores were near normal in all domains. Initial postoperative scores for Function and Pain decreased for the SURGICAL group and subsequently Total, Function, Image, and Satisfaction scores increased. Initial postoperative VEPTR scores in Mental Health and Pain decreased and Total, Function, and Image scores increased during subsequent visits.

CONCLUSION

Children with congenital scoliosis had SRS-22 scores that compare favorably with scores reported in the literature for adolescent idiopathic scoliosis. For SURGICAL and VEPTR patients with congenital scoliosis, SRS-22 Total, Function, and Image scores increased over time. Function, Image, and Pain require focus in children with congenital scoliosis. This is the first study that documents improvement in outcomes of VEPTR patients while in treatment.

LEVEL OF EVIDENCE

2.

Outcomes following removal of instrumentation after posterior spinal fusion

BACKGROUND

Although there is good evidence to support the removal of instrumentation for infection following posterior spine fusion, there are few studies that report outcomes following removal for late operative site pain. The purpose of this study was 3-fold: (1) to determine whether removal of instrumentation following posterior spinal fusion resolves preoperative pain, (2) to determine whether indolent infection not detected before removal of instrumentation is related to late operative site pain, and (3) to determine whether curve progression differs when spinal hardware is removed for infection versus late operative site pain.

METHODS

A retrospective study of consecutive patients aged 10 to 21 years, who underwent removal of instrumentation after posterior spinal fusion over a 10-year-period was conducted. Patient demographics, preoperative and postoperative imaging results, laboratory studies, and operative findings were reviewed. All patients had a minimum 2-year follow-up. Statistical analysis was performed using 2-sample t test, bivariate analysis, and multivariate logistic regression models.

RESULTS

Seventy-five patients were included. Indications for removal of spinal instrumentation were pain (57%), infection (28%), hardware failure (8%), and prominent hardware (7%). The mean time from index procedure to hardware removal was 2.8 years. The average loss of curve correction following complete hardware removal was 23.1 degrees. Patients who underwent removal of hardware because of infection had bigger changes in their curves than those without infection (mean, 33.8 degrees vs. 18.8 degrees). Of the 43 patients with pain, only 40% reported relief of their symptoms following removal of hardware. Sixteen of the 43 patients were found to have indolent infection confirmed by positive intraoperative culture results.

CONCLUSIONS

Patients should be cautioned that hardware removal after posterior spinal fusion may not provide complete pain relief. Furthermore, there is risk for curve progression following removal of instrumentation, particularly in the setting of infection. Back pain may be an indicator of infection, and intraoperative cultures should be taken at the time of implant removal.

LEVEL OF EVIDENCE

Level IV; retrospective case series.

Does the size of the rod affect the surgical results in adolescent idiopathic scoliosis? 5.5-mm versus 6.35-mm rod

BACKGROUND CONTEXT

Favorable clinical outcomes of surgical treatment with Cotrel-Dubousset instrumentation (CDI) or instrumentations that follow the principles of CDI, for adolescent idiopathic scoliosis (AIS) have been reported. However, there are few studies concerning the results with rods of different sizes.

PURPOSE

To find out whether the rod size affects the surgical results for AIS.

STUDY DESIGN

A retrospective cohort study based on the same spinal system with different sizes of rod.

PATIENT SAMPLE

A consecutive series of 93 patients, who underwent posterior correction with posterior instrumentation and fusion for AIS, were included and retrospectively analyzed.

OUTCOME MEASURES

Postoperative radiologic outcomes were evaluated using coronal curves, percentage of curve correction, and coronal global balance.

METHODS

Ninety-three patients treated during the period January 2000 to December 2008 were included in this study; 48 patients were treated with the Cotrel-Dubousset Horizon (CDH) M10 system with a 6.35-mm rod from January 2000 through December 2004, and a CDH M8 was used with a 5.5-mm rod in another 45 patients from January 2005 through December 2008. The Cobb angle, Risser grade, coronal curves, flexibility of curve, percentage of curve correction, coronal global balance, operative time, and estimated blood loss were measured and analyzed. The same parameters were used when the patient was followed at the OPD. All of the patients underwent regular follow-up for at least 2 years.

RESULTS

No statistical significance was observed in the demographic data, including age, sex, BMI, and Risser grade, between these 2 groups. The overall average percentage of correction was 60.0%±12.7%: 60.7%±12.5% for the CDH M10 group, and 59%±13.1% for the CDH M8 group. At the final follow-up, the overall average loss of correction was 4.8±3.9° for the CDH M10 group, and 4.3±4.0° for the CDH M8 group. The average percentage of correction at the final follow-up was 50.9%±15.1% for the CDH M10 group, and 51.1%±16.1% for the M8 group. No statistical significance could be observed in the radiologic parameters between these 2 groups.

CONCLUSION

The radiologic results for the 5.5-mm rod and the 6.35-mm rod were comparable in terms of correction, loss of correction, and coronal global balance.

The incidence and risk factors for short-term morbidity and mortality in pediatric deformity spinal surgery: an analysis of the NSQIP pediatric database

STUDY DESIGN

Retrospective review of a prospective cohort.

OBJECTIVE

To determine the incidence and risk factors for 30-day morbidity and mortality after pediatric deformity spinal surgery.

SUMMARY OF BACKGROUND DATA

Pediatric deformity spinal surgery is generally considered a safe and effective treatment option. The rising costs associated with spinal surgery and related perioperative complications have received national attention. Few studies with standardized definitions and data collection methods exist.

METHODS

A large, multicenter clinical registry specifically designed to collect pediatric surgical outcomes was queried for all patients undergoing spinal deformity surgery in 2012. Current Procedural Terminology codes were used to select patients undergoing anterior, posterior, and combined fusions. Detailed patient and case characteristics were analyzed. Thirty-day morbidity and mortality rates were calculated. Univariate and multivariate logistic regression analyses were used to identify patient characteristics, comorbidities, and operative variables predictive of complication.

RESULTS

In total, 2005 pediatric patients undergoing deformity spinal fusion were included. The rate of 30-day complications was 10.0%; with a mortality rate of 0.15% (3 patients), a morbidity rate of 8.4%, reoperation rate of 3.74%, and readmission rate of 3.94%. The morbidity rate was highest in the neuromuscular group (13.09%) and lowest in the idiopathic cohort (5.69%), P < 0.01). Compared with posterior fusions, anterior fusions and those extending to the pelvis were associated with higher complication rates (P < 0.01). Risk factors for complication included hepatobiliary disease (P = 0.03), cognitive impairment (P = 0.02), elevated American Society of Anesthesiologists class (P < 0.01), and prolonged operative time (P < 0.01).

CONCLUSION

The overall rate of 30-day morbidity after pediatric spinal deformity surgery was 10%. Multiple patient comorbidities and surgical duration and invasiveness were associated with an increased complication risk. These data may aid in the informed consent process, facilitate patient risk assessment, and allow quality comparisons between surgeons and institutions.

LEVEL OF EVIDENCE

2.

Restoration of thoracic kyphosis by simultaneous translation on two rods for adolescent idiopathic scoliosis

INTRODUCTION

Sagittal and axial corrections of the three-dimensional deformity characteristic of scoliosis remain challenging.

MATERIALS AND METHOD

The author developed a new technique for scoliosis correction consisting of the translation of vertebrae simultaneously towards two rods, which are pre-bent to the correct sagittal profile. Using two rods ensures both reduction and stabilization of the curve. The system includes stable anchorages with polyaxial-threaded extensions that connect to the rods. Deformity reduction is done by tightening nuts simultaneously and progressively on the two rods. Results demonstrate the efficiency of this technique to achieve normal thoracic kyphosis (>20°) in all 99 patients, with a mean gain of 19° of thoracic kyphosis in hypokyphotic cases. Coronal correction was 70-80% with a vertebral rotation gain of 40% where derotation connectors were used.

CONCLUSIONS

In a large consecutive series of patients, this new technique allows to achieve a good 3D correction of the scoliosis.

Do anchor density or pedicle screw density correlate with short-term outcome measures in adolescent idiopathic scoliosis surgery?

STUDY DESIGN

Retrospective review.

OBJECTIVE

Determine if factors under surgeon control (anchor density or pedicle screw density) or those not under surgeon control (curve magnitude, levels requiring fusion, and curve flexibility) correlate with standard, short-term quality and outcome measures for adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Pedicle screw fixation has revolutionized posterior spinal instrumentation and fusion for adolescent idiopathic scoliosis and seems to provide greater radiographical coronal plane curve correction than less expensive constructs. Other clinically relevant improvements in outcome have been difficult to demonstrate.

METHODS

Retrospective review of 119 posterior spinal instrumentation and fusion cases for adolescent idiopathic scoliosis by 4 surgeons at 1 institution. Average follow-up was 586.7 days. Outcome measures were main thoracic curve correction, complications, reoperations, infection, intensive care unit days, length of stay, estimated blood loss, transfusion, procedure time, implant charges, and total hospital charges. "Surgeon-dependent" variables were implant density (fixation/instrumented level) and pedicle coefficient (implant density × percentage of anchors that are pedicle screws). "Surgeon-independent" variables were main thoracic curve magnitude, main thoracic curve flexibility, and levels fused. Correlations were estimated using Pearson correlation coefficients. One-way analysis of variance was used to estimate the effect of "type of surgeon" or "surgeon" on surgeon-dependent variables.

RESULTS

Complications, reoperations, and infections did not correlate with surgeon-dependent or surgeon-independent variables. Main thoracic curve correction correlated strongly with curve flexibility (correlation coefficient [cc] = 0.4089, P < 0.0001). Surgeon-independent variables were levels fused correlated significantly with procedure time (cc = 0.610, P < 0.001), hospital charges (cc = 0.309, P < 0.001), hospital length of stay (cc = 0.366 [P < 0.001]), implant charges (cc = 0.199, P < 0.047), and estimated blood loss (cc = 0.243, P < 0.013). Surgeon-dependent variables were implant density significantly correlated with implant charges (cc = 0.243, P < 0.015) and inversely with length of stay (cc = -0.236, P < 0.015). Pedicle coefficient was not significantly correlated with any outcome measure.

CONCLUSION

Levels fused, a surgeon-independent variable, had the most consistently strong correlations with standard short-term quality indicators. With physician grading by payers largely dependent on easily measured outcomes from medical records, hospital and billing records, physicians need to be aware of the surgeon-dependent and surgeon-independent variables that may affect their outcomes and cost-effectiveness profile.

LEVEL OF EVIDENCE

3.

Effectiveness of cross-linking posterior segmental instrumentation in adolescent idiopathic scoliosis: a 2-year follow-up comparative study

BACKGROUND CONTEXT

Surgeons continue to debate the need for a cross-link (CL) in posterior spinal instrumentation constructs with segmental pedicle screws in adolescent idiopathic scoliosis (AIS). Advantage of CLs is increased stiffness of the construct, and disadvantages include added expense and risk of late operative-site pain and pseudarthrosis.

PURPOSE

To compare the effectiveness of using CLs versus using no cross-links (NCLs) in posterior segmental instrumentation in AIS.

STUDY DESIGN

Retrospective comparative study, level of evidence 3.

PATIENT SAMPLE

Seventy-five AIS patients less than 21 years of age, who underwent posterior spinal instrumentation with segmental pedicle screws (25 with CLs and 50 with NCLs) at a single institution with 2-year follow-up, are described.

OUTCOME MEASURES

Physiologic measures include imaging: thoracic and lumbar Cobb angles, correction rate, apical vertebral translation (AVT), and apical vertebral rotation (AVR); self-report measures include Scoliosis Research Society (SRS) domain outcome scores.

METHODS

Preoperative (pre-op) and postoperative first erect, 1-year, and 2-year follow-up radiographs were measured. Instrumentation-related complications and normalized SRS scores were recorded. Independent sample t test, χ(2) test, and repeated-measures analysis of variance were used for analyses.

RESULTS

The average age at surgery was 14 years, the mean pre-op Cobb angle was 57°, and the mean number of levels fused was 10.9. The groups were similar preoperatively with respect to age, sex, Lenke curve, Cobb angle, AVT, and Risser grade and were similar intraoperatively for levels fused and anchor density. There was no difference in AVR, Cobb angle, correction rate, or AVT between the groups (p>.05). Complications included one wound infection in the CL group and one painful scar in the NCL group. There were no differences in SRS domain scores.

CONCLUSION

We observed no differences in maintenance of correction, SRS scores, and complications with or without cross-linking posterior segmental instrumentation in AIS patients over 2-year follow-up. Further follow-up is necessary.

Reinstrumentation for rapid curve progression after implant removal following posterior instrumented fusion in adolescent idiopathic scoliosis: a case report

BACKGROUND CONTEXT

Spinal implants are occasionally removed due to infection or soft tissue irritation secondary to prominence. Several studies have reported loss of scoliotic curve correction after implant removal. However, further review of the literature reveals no similar cases of rapid curve progression following implant removal in patients with adolescent idiopathic scoliosis (AIS) necessitating repeat posterior instrumented fusion.

PURPOSE

To describe a 15-year-old female AIS patient treated by posterior instrumented fusion, who developed unusual rapid coronal and sagittal curve progression after implant removal.

STUDY DESIGN

Case report.

METHODS

Retrospective case report.

RESULTS

A 15-year-old female with Lenke type 1A AIS underwent a successful posterior spinal fusion with instrumentation. She initially had no complications after surgery, but three years after instrumentation, her implants were removed due to pain secondary to implant prominence. Fifteen months after removal, the main thoracic curve increased, compared with radiographs taken before removal, from 29° to 57°. This development required the patient to undergo additional surgery, which involved multiple osteotomies and posterior reinstrumentation.

CONCLUSIONS

We must acknowledge that a remarkable amount of progression can occur rapidly following implant removal in scoliotic patients. Taking this into consideration,we need to carefully explain to patients that removal of their implants entails a risk of progressive deformity and that they need to follow-up with their physician after implant removal.

Complications of surgical treatment of pediatric spinal deformities

Surgery in a child with spinal deformity is challenging. Although current orthopedic practice ensures good long-term surgical results, complications occur. Idiopathic scoliosis represents the most extensively investigated deformity of the pediatric spine. Nonidiopathic deformities of the spine are at higher risk for perioperative and long-term complications, mainly because of underlying comorbidities. A multidisciplinary treatment strategy is helpful to assure optimization of medical conditions before surgery. Awareness of complications that occur during or after spine surgery is essential to avoid a poor outcome and for future surgical decision making. This article summarizes the complications of surgical treatment of the growing spine.

Radiographic and patient-based outcome analysis of different bone-grafting techniques in the surgical treatment of idiopathic scoliosis with a minimum 4-year follow-up: allograft versus autograft/allograft combination

BACKGROUND CONTEXT

Autograft and allograft have been equally successful in achieving arthrodesis, but whether there is any difference in their effect on patient outcome, especially early, has not been determined.

PURPOSE

To determine if autograft in addition to allograft is associated with decreased healing period pain, increased early function, or both.

STUDY DESIGN

This is a retrospective comparative case series.

PATIENT SAMPLE

A sample of 47 patients, 20 years or younger with adolescent idiopathic scoliosis treated by the same surgeon at the same institution using third-generation segmental spinal instrumentation and arthrodesis.

OUTCOME MEASURE

Function and pain were quantified at periodic intervals using the Scoliosis Research Society (SRS) health-related quality of life (HRQoL) questionnaire. Clinical and radiographic follow-ups were completed.

METHODS

Freeze-dried corticocancellous allograft (AL) was used in 26 patients and allograft plus iliac crest autograft (AL-AU) in 21 patients. Radiographs and outcome measures, including SRS-24 or SRS-22 HRQoL questionnaires, were obtained preoperatively and at intervals with a 4-year follow-up available for 92% (25/26) of AL patients and 90% (19/21) of AL-AU patients.

RESULTS

There were no differences between the AL and AL-AU groups' ages, curve patterns, and complications. Neither group had a major complication or pseudoarthrosis. There were no main curve size differences at any interval. Pain scores were similar at all intervals: AL/AL-AU preoperative, 4.1/4.0; early follow-up (<1 year), 3.7/4.1; midterm follow-up (1-2 years), 4.4/4.6; and late follow-up (>3 years), 4.1/4.0. Function scores were also similar at all intervals: AL/AL-AU preoperative, 4.7/4.6; early follow-up, 4.2/4.3; midterm follow-up, 4.9/4.9; and late follow-up, 4.5/4.4.

CONCLUSIONS

The addition of autograft to allograft did not result in decreased pain or increased function at any time interval up to 4 years. We conclude that the addition of iliac crest autograft does not result in any advantage over freeze-dried allograft alone in the treatment of adolescent idiopathic scoliosis.

Biomechanical evaluation of a novel posterior integrated clamp that attaches to an existing posterior instrumentation for use in thoracolumbar revision

STUDY DESIGN

An in vitro biomechanical study.

PURPOSE

To evaluate the biomechanics of a novel posterior integrated clamp (IC) that extends on an already implanted construct in comparison to single long continuous bilateral pedicle screw (BPS) and rod stabilization system.

OVERVIEW OF LITERATURE

Revision surgery in the thoracolumbar spine often necessitates further instrumentation following a failed previous back surgery. Stability of these reconstructed constructs is not known.

METHODS

Six osteoligamentous T12-L5 calf spines were tested on a spine motion simulator in the following configurations: intact, four level constructs (T13-L4), three level constructs (L1-L4), and two level constructs (L2-L4), by varying the ratio between BPS and IC. A load control protocol of 8 Nm moments was applied at a rate of 1°/sec to establish the range of motion value for each construct in flexion-extension, lateral bending, and axial rotation. Statistical analysis was performed on raw data using repeated measures analysis of variance and significance was set at p<0.05.

RESULTS

On an average, the reduction in motion for the four level continuous pedicle screw and rod construct (67%) was similar to those extended with integrated clamps (64%). Furthermore, for three level and two level constructs, no significant difference was observed between continuous pedicle screw constructs and those revised with the integrated clamps (regardless of the ratio between BPS and IC).

CONCLUSIONS

The novel posterior IC showed equivalent biomechanical rigidity to continuous pedicle screw rod constructs in revision scenarios. Clinical studies on posterior rod adjunct systems are necessary to confirm these results.

Current concepts and controversies on adolescent idiopathic scoliosis: Part I

Adolescent idiopathic scoliosis is the most common spinal deformity encountered by General Orthopaedic Surgeons. Etiology remains unclear and current research focuses on genetic factors that may influence scoliosis development and risk of progression. Delayed diagnosis can result in severe deformities which affect the coronal and sagittal planes, as well as the rib cage, waistline symmetry, and shoulder balance. Patient's dissatisfaction in terms of physical appearance and mechanical back pain, as well as the risk for curve deterioration are usually the reasons for treatment. Conservative management involves mainly bracing with the aim to stop or slow down scoliosis progression during growth and if possible prevent the need for surgical treatment. This is mainly indicated in young compliant patients with a large amount of remaining growth and progressive curvatures. Scoliosis correction is indicated for severe or progressive curves which produce significant cosmetic deformity, muscular pain, and patient discontent. Posterior spinal arthrodesis with Harrington instrumentation and bone grafting was the first attempt to correct the coronal deformity and replace in situ fusion. This was associated with high pseudarthrosis rates, need for postoperative immobilization, and flattening of sagittal spinal contour. Segmental correction techniques were introduced along with the Luque rods, Harri-Luque, and Wisconsin systems. Correction in both coronal and sagittal planes was not satisfactory and high rates of nonunion persisted until Cotrel and Dubousset introduced the concept of global spinal derotation. Development of pedicle screws provided a powerful tool to correct three-dimensional vertebral deformity and opened a new era in the treatment of scoliosis.

Avaliação do posicionamento da aorta em pacientes com escoliose idiopática do adolescente

OBJETIVO: Avaliar o posicionamento da aorta em pacientes com escoliose. MÉTODOS: Foram realizados exames de imagem em pacientes ambulatoriais com escoliose idiopática do adolescente e em um grupo formado por pacientes hígidos, sendo analisados seis parâmetros: comprimento do corpo vertebral, largura, distância aorta-corpo, diâmetro da aorta, distância aorta-canal e ângulo corpo-aorta. RESULTADOS: As curvas variaram entre T3 e L2 com ângulos de Cobb de 46° e 114°. Pela classificação de Lenke os tipos 1AN e 1BN ocorreram em 20% dos casos, além de 1CN, 3BN, 3C+ com 13,3 % e 1B+, 3C- com 6,7 %. As vértebras próximas ao ápice da curva no grupo escoliose apresentam valores superiores às do grupo controle (em T8 com média de 86,93° no grupo escoliose e média 49,07 no grupo controle (p < 0,0001). CONCLUSÃO: Quanto mais próximo do ápice da deformidade, maior a póstero-lateralização da aorta.

Influence of screw type on initial coronal and sagittal radiological correction with hybrid constructs in adolescent idiopathic scoliosis. Correction priorities

BACKGROUND

Pedicle screw constructs for spinal instrumentation in patients with adolescent idiopathic scoliosis (AIS) are effective in providing coronal plane correction but can result in loss of kyphosis, which in turn can lead to loss of lordosis. Hybrid constructs have been found superior over pedicle screw constructs in terms of thoracic kyphosis restoration. In this study, our objective was to compare outcomes with monoaxial versus polyaxial screws in an AIS population treated with hybrid constructs.

HYPOTHESIS

Monoaxial screws provide better correction in the coronal plane but result in loss of thoracic kyphosis, whereas thoracic kyphosis is preserved when polyaxial screws are used.

MATERIAL AND METHODS

We retrospectively analysed data from 60 patients (mean age, 15years) with Lenke 1, 2, or 3 AIS treated using a hybrid construct with self-retaining bilaminar hook claws cranially, pedicle screws between the last instrumented vertebra and T11 caudally, and sublaminar universal clamps between the two extremities of the construct. Monoaxial screws were used in the first 30 patients (MS group) and polyaxial screws in the next 30 patients (PS group). Student's t test was performed to compare the two groups in terms of thoracic Cobb angle correction and T4-T12 kyphosis 3 months after surgery.

RESULTS

No significant preoperative differences were found between the two groups. At last follow-up, the residual Cobb angle was significantly greater in the PS group than in the MS group (20.3° versus 15°) with a percentage of correction of 72.1% in the MS group versus 64.8% in the PS group. In the sagittal plane, the thoracic kyphosis was significantly greater in the PS group than in the MS group (26.6° versus 23°).

DISCUSSION

This preliminary study shows that, even within a population managed using hybrid constructs, which are associated with less iatrogenic hypokyphosis, differences exist according to the technique used. The importance of sagittal spinal balance has been abundantly documented in the literature, and sagittal malalignment, particularly due to iatrogenic factors, is associated with poorer clinical outcomes in adults with spinal deformities. Therefore, there is a critical need to determine whether the treatment priority is optimal correction in the coronal plane or in the sagittal plane. We believe that the main focus should be sagittal plane correction, even at the expense of a slight decrease in coronal plane correction. Long-term studies are needed to confirm our preliminary findings.

Apical wiring technique in surgical treatment of adolescent idiopathic scoliosis: the intermediate outcomes between Lenke types

STUDY DESIGN

Retrospective cohort study of apical wiring technique for surgical treatment of adolescent idiopathic scoliosis patients.

OBJECTIVE

To evaluate the intermediate outcome of adolescent idiopathic scoliosis patients treated with apical wiring technique.

SUMMARY OF BACKGROUND DATA

Regarding surgical treatment for adolescent idiopathic scoliosis, there are reports of the superiority of coronal plane correction using all-screw constructs compared with all-hook or hybrid constructs. Major limitations of all-screw constructs are thoracic hypokyphosis and increased proximal junctional kyphosis. There are few reports about apical wiring technique outcomes and no reports of this surgical technique comparing Lenke types.

METHODS

Consecutive adolescent idiopathic scoliosis patients treated with apical wiring technique were analyzed. Inclusion criteria were patient 21 years old or younger, who underwent a posterior only surgical correction with a follow-up of at least 2 years. Radiographic data were analyzed according to the criteria given by Lenke and colleagues. The radiographic parameters included global balance, Cobb angle, curve flexibility, apical vertebral translation, tilt angle of lower instrumented vertebra, angle of caudal disk to the lower instrumented vertebra, thoracic kyphosis, lumbar lordosis, and proximal junctional angle preoperatively and postoperatively.

RESULTS

There was a significant improvement of Cobb angle in every Lenke type with an average correction of 74.6%. At latest follow-up, the average loss of correction was 3.5% (1.9 degrees). The greatest loss of correction for the minor curve of Lenke 2 was 14.1% (5.8 degrees). There was an improvement of thoracic kyphosis in hypokyphosis group (1.9-21.1 degrees; P<0.001) and hyperkyphosis group (49.8-33.2 degrees; P=0.001). Thoracic normokyphosis alignment was also preserved. No cases of abnormal proximal junctional kyphosis were noted in this cohort.

CONCLUSIONS

Apical wiring technique for surgical treatment of adolescent idiopathic scoliosis provides an average correction of 71.1% at 3.4 years of average follow-up with harmonious sagittal plane correction even with preexisting abnormal thoracic kyphosis.

Repeat surgical interventions following "definitive" instrumentation and fusion for idiopathic scoliosis: five-year update on a previously published cohort

STUDY DESIGN

A retrospective case series.

OBJECTIVE

To identify the overall reoperation rate and factors contributing to reoperation in a recent 5-year cohort of patients (2003-2007) undergoing spinal deformity surgery. These patients were compared with a previously published 15-year cohort of consecutive patients (1988-2002) from the same institution to assess for any significant differences in reoperation rates.

SUMMARY OF BACKGROUND DATA

In a previously published report from this institution, the reoperation rate for patients with idiopathic scoliosis treated during a 15-year period (1988-2002) was 12.9%. That group was predominantly treated with first-generation TSRH (Medtronic, Memphis, TN) implants and CD implants. Lower profile, more rigid implant systems are now used along with refined techniques for correction of scoliosis deformity. We hypothesized that these factors would lead to lower rates of reoperation. METHODS.: The medical records of 452 consecutive patients (older than 9 yr) surgically treated for idiopathic scoliosis at one institution during 5 years (2003-2007) were reviewed to identify those who required reoperation.

RESULTS

The reoperation rate for this cohort was 7.5% (34 of 452 patients). Compared with the prior cohort, significant decreases were noted with regard to total reoperation rate as well as reoperation due to infection and pseudarthrosis. Trends were noted toward decreased rates of reoperation due to prominent implants, dislodged implants, and implant proximity to vital structures. Within the newer cohort, a trend toward decreased reoperation rate was also noted for lower profile implant systems compared with first-generation TSRH implants.

CONCLUSION

With the evolution of newer lower profile segmental implant systems that provide more rigid fixation and with the advancements in techniques for deformity correction, the repeat surgical intervention rate for idiopathic scoliosis has decreased.

Unanticipated revision surgery in adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective case series.

OBJECTIVE

The objective of this study was to share our experience in the surgical treatment of adolescent idiopathic scoliosis (AIS), specifically the rate of revision surgeries and their indications.

SUMMARY OF BACKGROUND DATA

Minimizing AIS surgical morbidity includes prevention of short- and long-term complications that could require an unanticipated revision. There have been an increasing number of reports about revision rates and their causes in AIS. This study summarizes the experience of a large patient population treated by a single surgeon in a single institution.

METHODS

All patients who underwent surgical treatment for AIS between 10 and 20 years of age during 1983 to 2005 were reviewed. All revision surgeries performed during the same period were searched. The indications for revision and type of procedure performed were recorded.

RESULTS

A total of 502 patients with AIS underwent spinal fusion with instrumentation at an average age of 14.3 years at initial surgery. In 485 patients, the surgery consisted of posterior-only spinal fusion. A total of 24 revision surgeries were performed for 23 patients (4.9%; cumulative probability of revision = 8%). The primary indications for revision were residual rib deformity (n = 8), instrumentation dislodgement (n = 4), compensatory curve progression (n = 3), junctional kyphosis (n = 3), and symptomatic implants (n = 3). One patient had a late infection. There was 1 case of pseudoarthrosis. One patient requested scar revision. There were no cases of neurological deficit.

CONCLUSION

In this single-surgeon series, revision after the index spinal fusion was required for a relatively low proportion of patients. The main indications for revision were residual rib deformity, hook dislodgment, and progression of the unfused compensatory curve.

Simultaneous translation on two rods to treat adolescent idiopathic scoliosis: radiographic results in coronal, sagittal, and transverse plane of a series of 62 patients with a minimum follow-up of two years

STUDY DESIGN

Retrospective analysis of a consecutive cohort of 62 adolescent patients treated by posterior spinal fusion (PSF) with a minimum follow-up of 2 years.

OBJECTIVE

To present sagittal and coronal results of a specific method of reduction: the simultaneous translation on 2 rods (ST2R).

SUMMARY OF BACKGROUND DATA

The long-term outcome of surgically treated scoliosis is dependent not only on the coronal correction but also on restoration of sagittal curves. Recent publications confirm the moderate correction of thoracic hypokyphosis by posterior instrumentation with hooks or pedicle screws.

METHODS

Radiographic parameters were measured preoperatively and at 6 weeks, 1 year, and last follow-up (between 2 and 7.4 years) in a consecutive cohort of 62 patients with adolescent idiopathic scoliosis (AIS) treated by PSF. All operative procedures were performed by the same surgeon using stable anchorages such as screws or self-stabilizing claws. The screws and claws included a polyaxial-threaded extension, which was fixed to the rod with connecting clamps. Reduction of the deformity was obtained by gradual and alternate tightening of the nuts on all threaded extensions on both rods, which allowed the vertebrae to gradually approach the rods while the translation maneuver was performed.

RESULTS

In the coronal plane, the average main curve was reduced from 51° to 16° and maintained 70% of correction at last follow-up. In the sagittal plane, for patients with hypokyphosis (27 cases < 20°), the average kyphosis angle was significantly improved from 9° to 29° and maintained during follow-up (32°) with a mean gain of 23° (P < 0.0001). Only 1 patient reported hypokyphosis (18°) at last follow-up. For patients with normal kyphosis, the average gain was 8°.

CONCLUSION

In a large consecutive cohort, reduction of scoliosis by ST2R is a simple method that allows 70% of correction in the coronal plane, equivalent to screw instrumentations, and a restoration of normal thoracic kyphosis.

Evaluation of spinal instrumentation rod bending characteristics for in-situ contouring

Bending characteristics were studied in rods used for spinal instrumentation at in-situ contouring conditions. Five groups of five 6 mm diameter rods made from: cobalt alloy (VITALLIUM), titanium-aluminum-vanadium alloy (SDI™), β-titanium alloy (TNTZ), cold worked stainless steel (STIFF), and annealed stainless steel (MALLEABLE) were studied. The bending procedure was similar to that typically applied for in-situ contouring in the operating room and included two bending cycles: first--bending to 21-24° under load with further release of loading for 10 min, and second--bending to 34-37° at the previously bent site and release of load for 10 min. Applied load, bending stiffness, and springback effect were studied. Statistical evaluation included ANOVA, correlation and regression analysis. TNTZ and SDI™ rods showed the highest (p < 0.05) springback at both bending cycles. VITALLIUM and STIFF rods showed mild springback (p < 0.05). The least (p < 0.05) springback was observed in the MALLEABLE rods. Springback significantly correlated with the bend angle under load (p < 0.001). To reach the necessary bend angle after unloading, over bending should be 37-40% of the required angle in TNTZ and SDI™ rods, 27-30% in VITALLIUM and STIFF rods, and around 20% in MALLEABLE rods.

Simultaneous translation on two rods is an effective method for correction of hypokyphosis in AIS: radiographic results of 24 hypokyphotic thoracic scoliosis with 2 years minimum follow-up

Recent publications confirm that moderate correction of thoracic hypokyphosis can be achieved by posterior instrumentation with hooks or pedicle screws. Twenty-four prospective and consecutive thoracic adolescent scoliosis patients with hypokyphosis (<20°) were operated on by posterior spinal fusion (PSF) with a specific method of reduction: Simultaneous translation on two rods (ST2R), performed by the same surgeon using stable anchorages such as screws or self-stabilizing claws. Radiographic parameters were measured preoperatively, at 1 month, 1 year and at 2 years minimum follow-up. In the coronal plane, the average main curve was significantly reduced from 51° to 17° and maintained at last follow-up, corresponding to an average correction of 67%. In the sagittal plane, the average kyphosis angle was significantly improved from 9° to 30° postoperatively and to 32° at last follow-up, corresponding to a mean gain of 23°. The 24 patients reported normal kyphosis at last follow-up (≥20°). Reduction of scoliosis by ST2R is an effective method that gives coronal correction equivalent to all screw constructs and allows restoration of normal thoracic kyphosis.

Thoracic pedicle subtraction osteotomy in the treatment of severe pediatric deformities

The traditional surgical treatment of severe spinal deformities, both in adult and pediatric patients, consisted of a 360° approach. Posterior-based spinal osteotomy has recently been reported as a useful and safe technique in maximizing kyphosis and/or kyphoscoliosis correction. It obviates the deleterious effects of an anterior approach and can increase the magnitude of correction both in the coronal and sagittal plane. There are few reports in the literature focusing on the surgical treatment of severe spinal deformities in large pediatric-only series (age <16 years old) by means of a posterior-based spinal osteotomy, with no consistent results on the use of a single posterior-based thoracic pedicle subtraction osteotomy in the treatment of such challenging group of patients. The purpose of the present study was to review our operative experience with pediatric patients undergoing a single level PSO for the correction of thoracic kyphosis/kyphoscoliosis in the region of the spinal cord (T12 and cephalad), and determine the safety and efficacy of posterior thoracic pedicle subtraction osteotomy (PSO) in the treatment of severe pediatric deformities. A retrospective review was performed on 12 consecutive pediatric patients (6 F, 6 M) treated by means of a posterior thoracic PSO between 2002 and 2006 in a single Institution. Average age at surgery was 12.6 years (range, 9-16), whereas the deformity was due to a severe juvenile idiopathic scoliosis in seven cases (average preoperative main thoracic 113°; 90-135); an infantile idiopathic scoliosis in two cases (preoperative main thoracic of 95° and 105°, respectively); a post-laminectomy kypho-scoliosis of 95° (for a intra-medullar ependimoma); an angular kypho-scoliosis due to a spondylo-epiphisary dysplasia (already operated on four times); and a sharp congenital kypho-scoliosis (already operated on by means of a anterior-posterior in situ fusion). In all patients a pedicle screws instrumentation was used, under continuous intra-operative neuromonitoring (SSEP, NMEP, EMG). At an average follow-up of 2.4 years (range, 2-6) the main thoracic curve showed a mean correction of 61°, or a 62.3% (range, 55-70%), with an average thoracic kyphosis of 38.5° (range, 30°-45°), for an overall correction of 65% (range, 60-72%). Mean estimated intra-operative blood loss accounted 19.3 cc/kg (range, 7.7-27.27). In a single case (a post-laminectomy kypho-scoliosis) a complete loss of NMEP occurred, promptly assessed by loosening of the initial correction, with a final negative wake-up test. No permanent neurologic damage, or instrumentation related complications, were observed. According to our experience, posterior-based thoracic pedicle subtraction osteotomies represent a valuable tool in the surgical treatment of severe pediatric spinal deformities, even in revision cases. A dramatic correction of both the coronal and sagittal profile may be achieved. Mandatory the use of a pedicle screws-only instrumentation and a continuous intra-operative neuromonitoring to obviate catastrophic neurologic complications.