Deep Surgical Site Infection Following 2344 Growing-Rod Procedures for Early-Onset Scoliosis: Risk Factors and Clinical Consequences

Maximal Force Generated by Magnetically Controlled Growing Rods Decreases With Rod Lengthening

OBJECTIVES

To evaluate the maximal force generated by magnetically controlled growing rods (MCGRs) at three different lengthened positions.

SUMMARY OF BACKGROUND DATA

The introduction of MCGRs has been met with great enthusiasm by surgeons managing early-onset scoliosis. These devices offer the potential to decrease the cost and morbidity associated with repeated surgeries, compared to traditional growing rods. One potential negative consequences of growing rod treatments is the law of diminishing returns, where the spine length gained decrease with each subsequent lengthening. The cause of this phenomenon is unknown and probably multifactorial, yet it may be affected by the strength of the lengthening mechanism in the MCGRs.

METHODS

Twelve MCGRs (90-mm actuator length) were obtained and tested to evaluate the maximal force generated at different lengths. The maximal lengthening force measured in pounds-of-force generated by each rod was recorded at expansion lengths of 0, 25, and 40 mm. Longitudinal analysis was performed using mixed effects linear regression to account for repeated measures and variability between individual implants.

RESULTS

At 0 mm of actuator lengthening, the mean maximum force was 46.8 lb (standard deviation [SD] 2.06, range 43-50). At 25 mm of expansion, the mean maximum force was 44.9 lb (SD 2.48, range 39.4-49.5). At 40 mm of lengthening, the mean maximum force was 43.2 lb (SD 5.56, range 27.3-49.1). In the mixed effects linear model, there was a statistically significant decrease in the maximal force generated with progressive MCGR lengthening, at an average decrease of 0.089 lb of force (95% CI, 0.030-0.148; p = .003) per millimeter of lengthening.

CONCLUSION

There is a small but statistically significant decrease in the maximal force generated by MCGR as the rods are lengthened. The decrease in force generated may result in diminished spine length gained with each subsequent MCGR lengthening.

LEVEL OF EVIDENCE

Level IV.

Plastic Multilayered Closure in Pediatric Nonidiopathic Scoliosis Is Associated With a Lower Than Expected Incidence of Wound Complications and Surgical Site Infections

OBJECTIVE

To compare the incidence of surgical site infection (SSI) and wound complications between standard and plastic multilayered closure (PMC) in patients with pediatric nonidiopathic scoliosis undergoing primary or revision instrumentation or fusion.

STUDY DESIGN

Retrospective cohort study.

SUMMARY OF BACKGROUND DATA

Although PMC has been used for adult spine patients as well as infected spinal wound closure, it has not been reported as routine closure in the pediatric nonidiopathic scoliosis population.

METHODS

Patients with nonidiopathic scoliosis undergoing primary or revision instrumentation or fusion between 2013 and 2016 were enrolled. Clinical charts and operative reports were reviewed. Following September 2015, all patients with nonidiopathic scoliosis received PMC closure by plastic or orthopedic surgery. The SSI and wound complication incidence in patients undergoing PMC was compared to standard closure. The mean Risk Severity Score (RSS) for SSI, which uses patient characteristics to calculate the excepted SSI probability, was compared to the observed (actual) incidence. The CDC definition of SSI (infection ≤90 days of surgery) was used.

RESULTS

115 patients were identified, including 56 standard closure and 59 PMC (mean age of 10.6 years; 54.8% female; mean preoperative major curve = 57.5°). There was no significant difference in age, sex, race, preoperative major curve, BMI, hemoglobin, blood loss, mean RSS score, or etiology between both groups (p > .05). Following PMC implementation, the observed incidence of wound complications decreased significantly from 19.6% in standard closures to 5.1% in the PMC group (p = .02), and the SSI incidence decreased from 8.9% to 1.7% (p = .11). The overall change in the observed (actual) incidence versus expected (RSS score) incidence of SSI indicated a 7.1% reduction following PMC.

CONCLUSION

Utilizing PMC in patients undergoing spinal surgery for nonidiopathic scoliosis significantly decreases the incidence of wound complications. Surgeons should consider using PMC in patients with nonidiopathic scoliosis.

LEVEL OF EVIDENCE

Level II.

A comprehensive review of the diagnosis and management of congenital scoliosis

PURPOSE

To provide the reader with a comprehensive but concise understanding of congenital scoliosis METHODS: We have undertaken to summarize available literature on the pathophysiology, epidemiology, and management of congenital scoliosis.

RESULTS

Congenital scoliosis represents 10% of pediatric spine deformity and is a developmental error in segmentation, formation, or a combination of both leading to curvature of the spine. Treatment options are complicated by balancing growth potential with curve severity. Often associated abnormalities of cardiac, genitourinary, or intraspinal systems are concurrent and should be evaluated as part of the diagnostic work-up. Management balances the risk of progression, growth potential, lung development/function, and associated risks. Surgical treatment options involve growth-permitting systems or fusions.

CONCLUSION

Congenital scoliosis is a complex spinal problem associated with many other anomalous findings. Treatment options are diverse but enable optimization of management and care of these children.

A six-year observational study of 31 children with early-onset scoliosis treated using magnetically controlled growing rods with a minimum follow-up of two years

Aims

Magnetically controlled growing rod (MCGR) systems use non-invasive spinal lengthening for the surgical treatment of early-onset scoliosis (EOS). The primary aim of this study was to evaluate the performance of these devices in the prevention of progression of the deformity. A secondary aim was to record the rate of complications.

Patients and Methods

An observational study of 31 consecutive children with EOS, of whom 15 were male, who were treated between December 2011 and October 2017 was undertaken. Their mean age was 7.7 years (2 to 14). The mean follow-up was 47 months (24 to 69). Distractions were completed using the tailgating technique. The primary outcome measure was correction of the radiographic deformity. Secondary outcomes were growth, functional outcomes and complication rates.

Results

The mean Cobb angle was 54° (14° to 91°) preoperatively and 37° (11° to 69°) at the latest follow-up (p < 0.001). The mean thoracic kyphosis (TK) was 45° (10° to 89°) preoperatively and 42° (9° to 84°) at the latest follow-up. The mean T1-S1 height increased from 287 mm (209 to 378) to 338 mm (240 to 427) (p < 0.001) and the mean sagittal balance reduced from 68 mm (-76 to 1470) preoperatively to 18 mm (-32 to 166) at the latest follow-up. The mean coronal balance was 3 mm (-336 to 64) preoperatively and 8 mm (-144 to 64) at the latest follow-up. The mean increase in weight and sitting and standing height at the latest follow-up was 45%, 10% and 15%, respectively. The mean Activity Scale for Kids (ASKp) scores increased in all domains, with only personal care and standing skills being significant at the latest follow-up (p = 0.02, p = 0.03). The improvements in Cobb angle, TK and T1-S1 heights were not related to gender, the aetiology of the EOS, or whether the procedure was primary or conversion from a conventional growing rod system. A total of 21 children developed 23 complications at a rate of 0.23 per patient per year. Seven developed MCGR-specific complications. Complications developed at a mean of 38 months (3 to 67) after the initial surgery and required 22 further procedures. Children who developed a complication were more likely to be younger, have syndromic EOS, and have a single-rod construct (6.9 versus 9.3 years, p = 0.034).

Conclusion

The progression of EOS can be controlled using MCGRs allowing growth and improved function. Younger and syndromic children are more likely to develop complications following surgery. Cite this article: Bone Joint J 2018;100-B:1187-1200.

Early-onset Scoliosis: Contemporary Decision-making and Treatment Options

Early-onset scoliosis (EOS) describes a wide array of diagnoses and deformities exposed to growth. This potentially life-threatening condition is still 1 of the biggest challenges in pediatric orthopaedics. The enlightenment of Bob Campbell's thoracic insufficiency syndrome concept and the negative impact of the earlier short and straight spine fusion approach on respiratory function and survival have fueled the evolution of EOS care. Despite all the progress made, growth-friendly spine surgery remains to be a burden to patients and caregivers. Even down-sized implants and remote-controlled noninvasive rod expansions do not omit unexpected returns to the operating room: failures of foundations, rod breakage, difficulties to keep the sagittal balance, progressive transverse plane deformities, stiffening, and the need for final instrumented fusion are still common. However, past experience and the current multitude of surgical strategies and implants have sharpened the decision-making process, patients with thoracic insufficiency syndrome require earliest possible vertical expandable prosthetic titanium ribs application. Flexible deformities below 60 degrees, with normal spinal anatomy and without thoracic involvement, benefit from serial Mehta casting which revived as a long available but not-used strategy. In case of progression, standard double growing rods or-if available, affordable, and applicable-magnetically controlled motorized rods provide deformity control and growth promotion. Shilla growth-guiding technique is a less costly alternative. Its lack of stiff lengthening boxes or actuators may be beneficial in difficult deformities. Anterior convex flexible tethering promises benefits of sparing the trunk muscles and keeping mobility. However, this step towards a true nonfusion concept has yet to stand the test of broad clinical application.

Outcomes of growing rod surgery for severe compared with moderate early-onset scoliosis: a matched comparative study

Aims

The aim of this study was to compare the outcomes of surgery using growing rods in patients with severe versus moderate early-onset scoliosis (EOS).

Patients and Methods

A review of a multicentre EOS database identified 107 children with severe EOS (major curve ≥ 90°) treated with growing rods before the age of ten years with a minimum follow-up of two years and three or more lengthening procedures. From the same database, 107 matched controls with moderate EOS were identified.

Results

The mean preoperative major curve was 101° (90 to 139) in the severe group and 67° (33° to 88°) in the moderate group (p < 0.001), which was corrected at final follow-up to 57° (10° to 96°) in the severe group and 40° (3° to 85°) in the moderate group (p < 0.001). T1-S1 height increased by a mean of 54 mm (-8 to 131) in the severe group and 27 mm (-4 to 131) in the moderate group at the initial surgery (p < 0.001), and by 50 mm (-17 to 200) and 54 mm (-11 to 212), respectively, during distraction (p = 0.84). The mean number of complications per patient was 2.6 (0 to 14) in the severe group and 1.9 (0 to 10) in the moderate group (p = 0.040). Five patients (4.7%) in the severe group and three (2.8%) in the moderate group developed a neurological deficit postoperatively (p = 0.47).

Conclusion

Severe EOS can be treated effectively using growing rods, but the risk of complications is high. Cite this article: Bone Joint J 2018;100-B:772-9.

Treatment strategies for early-onset scoliosis

Early-onset scoliosis (EOS) is defined as a spinal deformity occurring before the age of ten years.

Untreated EOS or early spinal fusion resulting in a short spine is associated with increased mortality and cardiopulmonary compromise.

EOS may progress rapidly, and therefore prompt clinical diagnosis and referral to a paediatric orthopaedic or spine unit is necessary.

Casting under general anaesthesia can be effective and may prevent or delay the need for surgery in curves of less than 60°.

‘Growing’ rods (traditional or magnetically-controlled) represent the standard surgical treatment in progressive curves of 45° or greater.

Children with congenital scoliosis associated with fused ribs benefit from surgery with a vertical titanium prosthetic rib.

Surgery with growth-friendly instrumentation is associated with a high risk of complications.

Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170051

An NIHR-approved two-year observational study on magnetically controlled growth rods in the treatment of early onset scoliosis

Aims

The primary aim of this study was to evaluate the performance and safety of magnetically controlled growth rods in the treatment of early onset scoliosis. Secondary aims were to evaluate the clinical outcome, the rate of further surgery, the rate of complications, and the durability of correction.

Patients and Methods

We undertook an observational prospective cohort study of children with early onset scoliosis, who were recruited over a one-year period and followed up for a minimum of two years. Magnetically controlled rods were introduced in a standardized manner with distractions performed three-monthly thereafter. Adverse events which were both related and unrelated to the device were recorded. Ten children, for whom relevant key data points (such as demographic information, growth parameters, Cobb angles, and functional outcomes) were available, were recruited and followed up over the period of the study. There were five boys and five girls. Their mean age was 6.2 years (2.5 to 10).

Results

The mean coronal Cobb angle improved from 57.6° (40° to 81°) preoperatively, 32.8° (28° to 46°) postoperatively, and 41° (19° to 57°) at two years. Five children had an adverse event, with four requiring return to theatre, but none were related to the device. There were no neurological complications or infections. No devices failed. One child developed a proximal junctional kyphosis. The mean gain in spinal column height from T1 to S1 was 45.4 mm (24 to 81) over the period of the study.

Conclusion

Magnetically controlled growth rods provide an alternative solution to traditional growing rods in the surgical management of children with early onset scoliosis, supporting growth of the spine while controlling curve progression. Their use has clear psychosocial and economic benefits, with the reduction of the need for repeat surgery as required with traditional growing rods. Cite this article: Bone Joint J 2018;100-B:507-15.

Staged insertion of growing rods in severe scoliosis

PURPOSE

The objective of this retrospective chart and radiographic review was to present the clinical outcomes and complication rate of a staged approach to modern dual growing-rod (GR) surgery when treating children with severe early onset scoliosis.

METHODS

Fifteen patients received a 6-mm dual GR system. During Stage 1, pairs of end vertebra were exposed in a subperiosteal fashion, instrumented, grafted, and fused. Stage 2 was performed, on average, 5 months later (range 8-35 weeks) and the fused foundations were connected with two growing rods under skull-femoral traction. Clinical and operative notes were reviewed and all complications were recorded. Radiographic measurements were assessed at pre-index, with intraoperative traction during Stage 1, post-Stage 2 and at most recent follow-up. Statistical analyses were performed to evaluate change in scoliosis and kyphosis.

RESULTS

At initial surgery, the average age was 8.17 ± 1.5 years. The mean Cobb angle was 88.1° ± 14.0°, corrected to 60.3° ± 8.7° (p < 0.001) with intraoperative traction in Stage 1, preserved after Stage 2 instrumentation (59.5° ± 9.6°, p = 0.69), and maintained with subsequent lengthenings (60.6° ± 12.8°, p = 0.73). Hyperkyphosis (11/15 patients) improved from 70.8° ± 15.7° to 46.6° ± 9.7° (p < 0.001). At minimum 2-year follow-up (range 24-80 months, mean 49.5), the complication rate was 14 (0.93 complications/patient), including 6 rod breakages, 6 superficial infections, and 2 deep infections. No anchor migration or pull-out was noted. Seven patients have undergone definitive posterior spinal fusion.

CONCLUSIONS

Staged insertion of dual GR systems permits strong distraction, with acceptable correction of severe deformities and minimal complications. These slides can be retrieved under Electronic Supplementary Material.

Does Vancomycin Powder Decrease Surgical Site Infections in Growing Spine Surgery?: A Preliminary Study

BACKGROUND

Vancomycin powder has been demonstrated to be safe in children, and yet there are no data on its use to reduce surgical site infections (SSIs) in surgery for early-onset scoliosis.

METHODS

We performed a retrospective study of our patients treated for early-onset scoliosis in the period of 2010 to 2016. In 2010, we updated our standardized perioperative growing spine care path. The only later change was the gradual introduction of intrawound vancomycin powder. Procedures were categorized into either the control group (without vancomycin powder) or the experimental group (with vancomycin powder), with otherwise identical perioperative management. Initial insertion, revision, and lengthening procedures and final fusions were included. We compared the rate of postoperative SSIs per procedure between the groups.

RESULTS

Thirty-six patients who underwent 191 procedures met the inclusion criteria. The clinical and radiographic data were essentially the same between the groups. During the study period, 14 (39%) of the 36 patients developed ≥1 deep SSI. Only 2 patients had multiple acute infections. There were 87 procedures with 12 infections in the control group (SSI rate of 13.8% per procedure), while there were 104 procedures with 5 infections in the vancomycin group (4.8% per procedure). The difference in the SSI rate per procedure was significant (p = 0.038). The number of individual procedures needed to be performed using vancomycin to prevent an SSI was 10.9.

CONCLUSIONS

The use of vancomycin powder in growing spine surgery for early-onset scoliosis is associated with a significant decreased risk of SSI. It appears to be effective even when previous surgeries have been performed without its use.

LEVEL OF EVIDENCE

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

Cost analysis of a growth guidance system compared with traditional and magnetically controlled growing rods for early-onset scoliosis: a US-based integrated health care delivery system perspective

Purpose

Treating early-onset scoliosis (EOS) with traditional growing rods (TGR) is effective but requires periodic surgical lengthening, risking complications. Alternatives include magnetically controlled growing rods (MCGR) that lengthen noninvasively and the growth guidance system (GGS), which obviate the need for active, distractive lengthenings. Previous studies have reported promising clinical effectiveness for GGS; however the direct medical costs of GGS compared to TGR and MCGR have not yet been explored.

Methods

To estimate the cost of GGS compared with MCGR and TGR for EOS an economic model was developed from the perspective of a US integrated health care delivery system. Using dual-rod constructs, the model estimated the cumulative costs associated with initial implantation, rod lengthenings (TGR, MCGR), revisions due to device failure, surgical-site infections, device exchange, and final spinal fusion over a 6-year episode of care. Model parameters were from peer-reviewed, published literature. Medicare payments were used as a proxy for provider costs. Costs (2016 US$) were discounted 3% annually.

Results

Over a 6-year episode of care, GGS was associated with fewer invasive surgeries per patient than TGR (GGS: 3.4; TGR: 14.4) and lower cumulative costs than MCGR and TGR, saving $25,226 vs TGR. Sensitivity analyses showed that results were sensitive to changes in construct costs, rod breakage rates, months between lengthenings, and TGR lengthening setting of care.

Conclusion

Within the model, GGS resulted in fewer invasive surgeries and deep surgical site infections than TGR, and lower cumulative costs per patient than both MCGR and TGR, over a 6-year episode of care. The analysis did not account for family disruption, pain, psychological distress, or compromised health-related quality of life associated with invasive TGR lengthenings, nor for potential patient anxiety surrounding the frequent MCGR lengthenings. Further analyses focusing strictly on current generation technologies should be considered for future research.

Sagittal plane parameters in growing rod patients following final fusion

Almost half of growing rod (GR) patients that undergo final fusion (FF) have an extension of instrumented levels. The purpose of this study was to review sagittal plane radiographic parameters of patients with distal extension of instrumented levels at FF to those whose levels remained the same. Radiographs were assessed preoperatively, after GR insertion/first lengthening, following GR treatment before FFs, and after FF. Measurements included sagittal balance, lumbar lordosis, thoracic kyphosis, and distal junction angle (DJA). Twenty-one patients were included. There was no change in sagittal balance. There was a significant decrease in lordosis and kyphosis following initial GR implantation. Kyphosis and lordosis increased during the GR period, but remained unchanged at time of FF. DJA increased 8° on average. Seven patients had distal extension of instrumented levels at time of FF (average 2 levels, range: 1-4). Indication for distal extension was sagittal plane decompensation in four cases. When comparing patients who had distal extension at the time of FF to those whose levels remained the same, there was no difference in the change in sagittal balance, lordosis, or kyphosis. Final DJA was significantly smaller in those patients with distal extension. Most GR patients that undergo FF demonstrate acceptable correction of sagittal plane radiographic parameters. A small cohort of patients requires distal extension at FF due to sagittal plane decompensation.

LEVEL OF EVIDENCE

Level IV, Therapeutic.

What's New in Pediatric Spine Growth Modulation and Implant Technology for Early-Onset Scoliosis?

BACKGROUND

Early-onset scoliosis (EOS) affects roughly 1 to 2 out of 10,000 live births per year. Because this subset of patients has a yet to achieve a majority of their skeletal growth, a number of treatment challenges need to be addressed before surgical intervention. If left untreated, EOS can cause a number of problems throughout the patient's lifespan, particularly in regards to the growth of the thorax and pulmonary development. A wide variety of surgical systems and techniques are available to the treating surgeon.

METHODS

A review of the orthopaedic literature from 2010 to 2015 relating to pediatric spine growth modulation was performed. Ninety-eight papers were identified and, following exclusion criteria, a total of 31 papers were selected for further review.

RESULTS

This paper summarizes the recently published literature regarding growth-friendly spinal implants, the status of their Food and Drug Administration approval labeling as well as the indications, applications, and complications associated with their implementation.

CONCLUSIONS

There are a growing number of options at the surgeon's disposal when treating patients with EOS. As surgeons, we must continue to be vigilant in our demand for sound clinical evidence as we strive to provide optimal care for our patients. The rapidly advancing field of spinal growth modulation is exciting. More work must be done to further enhance our ability to predictably modulate growth in the pediatric spine.

How Does Hyperkyphotic Early-Onset Scoliosis Respond to Growing Rod Treatment?

BACKGROUND

Growing rods (GRs) pose a higher risk of kyphosis gain while improving coronal deformity with intermittent distractions in early-onset scoliosis (EOS), but in turn, increased kyphosis may also affect GR correction outcomes. However, there is a paucity of data regarding the effect of GRs on the sagittal spinal profiles in hyperkyphotic EOS. Thus, we aim to demonstrate how hyperkyphotic EOS responds to GRs treatment.

METHODS

Forty patients treated with GRs for EOS were included and categorized into a normal kyphosis (N) group [20 degrees≤thoracic kyphosis (TK)≤50 degrees] or hyperkyphosis group (K) group (TK≥50 degrees). Radiographic measurements were performed before and after the index surgery and at the last follow-up. The complications were identified and classified using the surgical complications grading system.

RESULTS

The N group included 13 patients with dual GRs and 6 patients with a single GR. The K group consisted of 17 patients with dual GRs and 4 patients with a single GR. The mean age at surgery in the N and K groups was 6.2±1.8 and 6.4±2.1 years, respectively. The N and K groups, respectively, had an average number of lengthenings of 4.2±2.0 and 4.3±2.3, with an average follow-up of 4.7±1.9 and 4.6±2.1 years, respectively. In the K group, TK was markedly reduced after the index surgery and slightly increased during follow-up, whereas changes in TK in the N group were not significant. The complication rate in the K group was significantly higher than in the N group (81.0% vs. 47.4%, P=0.046). The most common implant-related and alignment-related complication in both groups was rod fracture (17.5%) and proximal junctional kyphosis (22.5%), respectively. The complication events in the N group were 5 with grade I and 5 with grade IIA, whereas in the K group there were 8 with grade I and 11 with grade IIA.

CONCLUSIONS

GRs can effectively correct hyperkyphotic EOS, with the sagittal profile being successfully restored to normal range. However, hyperkyphotic EOS tends to experience more complications such as rod fracture and PJK.

LEVEL OF EVIDENCE

Level III.

Surgical Site Infections following Spine Surgery for Non-idiopathic Scoliosis

BACKGROUND

Surgical site infections (SSIs) following spine surgery in children and adolescents with nonidiopathic scoliosis are associated with increased morbidity and health care costs. Potentially modifiable risk factors for SSIs merit additional study in this population.

METHODS

A single-center, retrospective cohort study was performed from August 2008 through December 2013 in children and adolescents undergoing surgery for nonidiopathic scoliosis to determine the trends in SSI rate and causative microorganisms. A standardized perioperative antimicrobial prophylaxis regimen was developed from September-October 2008. Potential risk factors for SSIs were assessed by multivariable analysis using Poisson regression models. Fusion procedures and growing construct procedures were analyzed separately.

RESULTS

In all, 268 patients underwent 536 surgical procedures of whom 192 underwent 228 fusion procedures, 89 underwent 308 growing construct procedures, and 13 underwent both procedures during the study period. Twenty-one SSIs (3.9% of surgical procedures and 7.8% of patients) occurred within 90 days of surgery, 17 SSIs occurred after fusion procedures (4.5% of procedures and 8.9% of patients), and 4 SSIs occurred after growing construct procedures (1.3% of procedures and 4.5% of patients). There were 9 polymicrobial SSIs (42.9%). Of the 31 bacterial pathogens isolated, 48% were Gram-negative organisms. Among patients undergoing fusion procedures, SSIs were associated with underdosing of preoperative cefazolin [relative risk (RR)=4.99; 95% confidence interval (CI), 1.89-17.43; P=0.012] and tobramycin (RR=5.86; 95% CI, 1.90-18.06; P=0.002), underdosing of intraoperative (RR=5.65; 95% CI, 2.13-14.97; P=0.001) and postoperative (RR=3.86; 95% CI, 1.20-12.40; P=0.023) tobramycin, and any preoperative or intraoperative underdosing (RR=4.89; 95% CI, 1.70-14.12; P=0.003), after adjustment for duration of surgery. No factors were associated with SSIs in those undergoing growing construct procedures. During the study period, the SSIs rate declined (P<0.0001).

CONCLUSIONS

Underdosing of tobramycin and preoperative cefazolin were associated with an increased SSI risk among patients undergoing fusion procedures. Future multicenter studies should further investigate the generalizability of these findings.

LEVEL OF EVIDENCE

Level II-retrospective study.

Implant Complications After Magnetically Controlled Growing Rods for Early Onset Scoliosis: A Multicenter Retrospective Review

BACKGROUND

Traditional growing rods have a reported wound and implant complication rate as high as 58%. It is unclear whether the use of magnetically controlled growing rods (MCGR) will affect this rate. This study was performed to characterize surgical complications following MCGR in early onset scoliosis.

METHODS

A multicenter retrospective review of MCGR cases was performed. Inclusion criteria were: (1) diagnosis of early onset scoliosis of any etiology; (2) 10 years and younger at time of index surgery; (3) preoperative major curve size >30 degrees; (4) preoperative thoracic spine height <22 cm. Complications were categorized as wound related and instrumentation related. Complications were also classified as early (<6 mo from index surgery) versus late (>6 mo). Distraction technique and interval of distraction was surgeon preference without standardization across sites.

RESULTS

Fifty-four MCGR patients met inclusion criteria. There were 30 primary and 24 conversion procedures. Mean age at initial surgery was 7.3 years (range, 2.4 to 11 y), and mean duration of follow-up 19.4 months. Twenty-one (38.8%) of 54 patients had at least 1 complication. Fifteen (27.8%) had at least 1 revision surgery. Six (11.1%) had broken rods (2 to 4.5 and 4 to 5.5 mm rods); two 5.5 mm rods failed early (4 mo) and 4 late (mean=14.5 mo). Six (11.1%) patients experienced 1 episode of lack or loss of lengthening, of which 4 patients subsequently lengthened. Seven patients (13.0%) had either proximal or distal fixation-related complication at average of 8.4 months. Two patients (3.7%) had infections requiring incision and drainage; 1 early (2 wk) with wound drainage and 1 late (8 mo). The late case required removal of one of the dual rods.

CONCLUSIONS

This study shows that compared with traditional growing rods, MCGR has a lower infection rate (3.7% vs. 11.1%). MCGR does not appear to prevent common implant-related complications such as rod or foundation failure. The long-term implication remains to be determined.

LEVEL OF EVIDENCE

Level IV.

Performing a Definitive Fusion in Juvenile CP Patients is a Good Surgical Option

BACKGROUND

In juveniles with progressive curves, there is debate regarding the use of growth friendly implants versus definitive fusion. This study presents outcomes of juvenile cerebral palsy (CP) scoliosis patients who underwent definitive fusion before age 11.

METHODS

A review of a prospective, multicenter registry identified patients 10 years and younger who had a definitive posterior fusion for their CP scoliosis. Preoperative and postoperative demographic and radiographic changes were evaluated with descriptive statistics. Repeated measures analysis of variance were utilized to compare outcome scores.

RESULTS

Fourteen children with a mean age of 9.7 years (8.3 to 10.8 y) and a minimum of 2 years follow-up (range 2 to 3 y) were identified. The mean preoperative curve magnitude and pelvic obliquity was 84±25 degrees (range 63 to 144 degrees) and 25±14 degrees, respectively. All patients were skeletally immature with open triradiate cartilage. Three patients had unit rods with wires while the rest incorporated pedicle screws. Immediately postoperation, the average major curve was 25±17 degrees (P≤0.001, 71% correction rate). At most recent follow-up, the average major curve increased to 30±18 degrees (P≤0.001) for a 65% correction rate. Pelvic obliquity improved to 4±4 degrees (84% correction, P≤0.001) immediately postoperation and to 6±5 degrees (P=0.002) at latest follow-up for a 76% correction rate. None of the patients required revision surgery for progression. From pre to most recent follow-up, the CPchild Health outcome scores improved from 47 to 58 (P=0.019). One patient had a deep infection, and 1 patient had a broken rod that did not require any further treatment.

CONCLUSIONS

Progressive scoliosis in juvenile CP patients requires the surgeon to balance the need for further growth with the risks of progression or repeated surgical procedures. Our study demonstrates that definitive fusion once the curves approach 90 degrees results in significant radiographic and quality of life improvements, but further follow-up is needed to determine whether those results remain after skeletal maturity.

LEVEL OF EVIDENCE

Level IV-therapeutic.

Serial Casting for Infantile Idiopathic Scoliosis: Radiographic Outcomes and Factors Associated With Response to Treatment

BACKGROUND

Serial casting for early-onset scoliosis has been shown to improve curve deformity. Our goal was to define clinical and radiographic features that determine response to treatment.

METHODS

We retrospectively reviewed patients with idiopathic infantile scoliosis with a minimum of 2-year follow-up. Inclusion criteria were: progressive idiopathic infantile scoliosis and initial casting before 6 years of age. Two groups were analyzed and compared: group 1 (≥10-degree improvement in Cobb angle from baseline) and group 2 (no improvement).

RESULTS

Twenty-one patients with an average Cobb angle of 48 degrees (range, 24 to 72 degrees) underwent initial casting at an average age of 2.1 years (range, 0.7 to 5.4 y). Average follow-up was 3.5 years (range, 2 to 6.9 y). Sex, age at initial casting, magnitude of spinal deformity, and curve flexibility (defined as change in Cobb angle from pretreatment to first in-cast radiograph) were not significantly different between groups (P>0.05). Group 1 had a significantly higher body mass index (BMI) than group 2 at the onset of treatment (17.6 vs. 14.8, P<0.05). Univariate analysis of demographic, radiographic, and treatment factors revealed that only BMI was predictive of Cobb improvement (P=0.04; odds ratio=2.38). Group 1 (n=15) had a significantly lower Cobb angle (21 vs. 56 degrees) and rib vertebral angle difference (13 vs. 25 degrees) compared with group 2 at latest follow-up (P<0.05). A significantly larger proportion of children who were casted at less than 1.8 years of age had a Cobb angle <20 degrees at latest follow-up (P=0.03). Group 2 maintained stable clinical and radiograph parameters from pretreatment to most recent follow-up.

CONCLUSIONS

To maintain a homogeneous cohort, we excluded patients with syndromes and developmental delays. We believe that analyzing a homogeneous group provides more meaningful results than if we studied a heterogeneous sample. BMI was significantly associated with outcome such that for each unit increase in BMI, there is a 2.38× increase in the chance of improvement. Curve flexibility was similar between groups, which suggest that the amount of correction obtained at initial casting does not confirm treatment success. Key aspects of treatment that may determine success include age of less than 1.8 years at initiation of casting and derotation of the spine to correct rib vertebral angle difference of <20 degrees.

LEVEL OF EVIDENCE

Level IV-Therapeutic.

Risk factors for postoperative deep infection in bone tumors

BACKGROUND

Postoperative deep infection after bone tumor surgery remains a serious complication. Although there are numerous reports about risk factors for postoperative deep infection in general surgery, there is only a small number of reports about those for bone tumor surgery. This retrospective study aimed to identify risk factors for postoperative deep infection after bone tumor resection.

METHODS

We reviewed data of 681 patients (844 bone tumors) who underwent surgery. Associations between variables, including age, recurrent tumor, pathological fracture, surgical site (pelvis/other), chemotherapy, biological reconstruction, augmentation of artificial bone or bone cement, the use of an implant, intraoperative blood loss, operative time, additional surgery for complications, and postoperative deep infection were evaluated.

RESULTS

The rate of postoperative deep infection was 3.2% (27/844 tumors). A pelvic tumor (odds ratio [OR]: 3.4, 95% confidence interval [CI]: 1.0-11.3) and use of an implant (OR: 9.3, 95% CI: 1.9-45.5) were associated with an increased risk of deep infection.

CONCLUSIONS

This retrospective study showed that pelvic tumor and use of an implant were independent risk factors for deep infection. This information will help surgeons prepare an adequate surgical plan for patients with bone tumors.

Which Pediatric Orthopaedic Procedures Have the Greatest Risk of Adverse Outcomes?

BACKGROUND

Quality improvement in orthopaedic surgery has received increasing attention; however, there is insufficient information available about the perioperative safety of many common pediatric orthopaedic procedures. This study aimed to characterize the incidence of adverse events in a national pediatric patient sample to understand the risk profiles of common pediatric orthopaedic procedures, and to identify patients and operations that are associated with increased rates of adverse outcomes.

METHODS

A retrospective cohort study was conducted using the prospectively collected American College of Surgeons National Surgical Quality Improvement Program (NSQIP) Pediatric database. Pediatric patients who underwent 29 different orthopaedic procedures were identified in the 2012 NSQIP Pediatric database. The occurrence of any adverse event, infection, return to the operating room, and readmission within 30 days, were reported for each procedure. Multivariate regression was then used to identify the association of patient and operative characteristics with the occurrence of each adverse outcome.

RESULTS

A total of 8975 pediatric patients were identified. Supracondylar humerus fracture fixation was the most common procedure performed in this sample (2274 patients or 25.57% of all procedures), followed by posterior spinal fusion (1894 patients or 21.10% of all procedures). Adverse events occurred in 352 patients (3.92% of all patients). Four deaths were noted (0.04% of all patients), which only occurred in patients with nonidiopathic scoliosis undergoing spinal fusion. Infections occurred in 143 patients (1.59%), and 197 patients (2.19%) were readmitted within 30 days. Multiple patient characteristics and procedures were found to be associated with each adverse outcome studied.

CONCLUSIONS

Spinal fusion, multiaxial external fixation, and fasciotomy were procedures associated with increased rates of adverse outcomes within 30 days. Patients with obesity, ASA class ≥3, and impaired cognitive status also had increased rates of adverse outcomes. The results from this study of a large, national sample of pediatric orthopaedic patients are important for benchmarking and highlight areas for quality improvement.

LEVEL OF EVIDENCE

Level III-Prognostic.

Epidemiology of Deep Surgical Site Infections After Pediatric Spinal Fusion Surgery

STUDY DESIGN

Single-institution, retrospective case series.

OBJECTIVE

To determine whether the microbiology of deep surgical site infections (SSIs) after spinal fusion surgery for deformity has changed over the last decade at our institution.

SUMMARY OF BACKGROUND DATA

SSI after pediatric spinal deformity surgery results in significantly increased patient morbidity and health care costs. Although risk factors are multifactorial, prophylactic and treatment antibiotic coverage is based in part on historical epidemiologic data, which may evolve over time.

METHODS

This study represents a retrospective review of clinical and microbiology records of patients less than 21 years old who underwent spinal deformity surgery at a single institution between 2000 and 2012. Patients were included who underwent index surgery at our institution and developed a deep SSI. Patients with growth-preserving spine constructs were excluded.

RESULTS

The overall incidence of deep SSI was 3.6% (39/1094). The incidence of deep SSI following primary surgery was 3.3% (34/1034) and 8.3% (5/60) following revision surgery. The incidence of deep SSI varied by primary diagnosis: idiopathic (1.0%), neuromuscular (14.3%), syndromic (5.3%), congenital (5.7%), and kyphosis (0.0%). The most common inciting pathogens were Staphylococcus epidermidis (26%), methicillin-sensitive Staphylococcus aureus (MSSA, 18%), Propionibacterium acnes (P. acnes; 18%), and Escherichia coli (18%). Sixteen of the 18 (89%) gram-negative infections occurred in neuromuscular patients (P = 0.006). Between 2000 and 2006 and between 2007 and 2012, MSSA occurred in 2/18 (11%) and 5/21 (24%) of cases (P = 0.41), methicillin-resistant S. aureus occurred in 1/18 (6%) and 3/21 (14%) (P = 0.61), and P. acnes occurred in 3/18 (17%) and 4/21 (19%) (P = 1.0).

CONCLUSION

The epidemiology of deep SSI following spinal fusion for deformity in pediatric patients at our institution has not changed significantly during 13 years. Prophylactic antibiotic coverage for both gram-positive and gram-negative organisms may be indicated for patients with primary neuromuscular diagnoses.

LEVEL OF EVIDENCE

4.

Burden of Surgical Site Infections Associated with Select Spine Operations and Involvement of Staphylococcus aureus

BACKGROUND

Spine operations may be indicated for treatment of diseases including vertebral injuries, degenerative spinal conditions, disk disease, spinal misalignments, or malformations. Surgical site infection (SSI) is a clinically important complication of spine surgery. Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA), is a leading cause of post-spinal SSIs.

METHODS

PubMed and applicable infectious disease conference proceedings were searched to identify relevant published studies. Overall, 343 full-text publications were screened for epidemiologic, mortality, health care resource utilization, and cost data on SSIs associated with specified spine operations.

RESULTS

Surgical site infection rates were identified in 161 studies from North America, Europe, and Asia. Pooled average SSI and S. aureus SSI rates for spine surgery were 1.9% (median, 3.3%; range, 0.1%-22.6%) and 1.0% (median, 2.0%; range, 0.02%-10.0%). Pooled average contribution of S. aureus infections to spinal SSIs was 49.3% (median, 50.0%; range, 16.7%-100%). Pooled average proportion of S. aureus SSIs attributable to MRSA was 37.9% (median, 42.5%; range, 0%-100%). Instrumented spinal fusion had the highest pooled average SSI rate (3.8%), followed by spinal decompression (1.8%) and spinal fusion (1.6%). The SSI-related mortality rate among spine surgical patients ranged from 1.1%-2.3% (three studies). All studies comparing SSI and control cohorts reported longer hospital stays for patients with SSIs. Pooled average SSI-associated re-admission rate occurring within 30 d from discharge ranged from 20% to 100% (four studies). Pooled average SSI-related re-operation rate was 67.1% (median, 100%; range, 33.5%-100%). According to two studies reporting direct costs, spine surgical patients incur approximately double the health care costs when they develop an SSI.

CONCLUSIONS

Available published studies demonstrate a clinically important burden of SSIs related to spine operations and the substantial contribution of S. aureus (including MRSA). Preventive strategies aimed specifically at S. aureus SSIs could reduce health care costs and improve patient outcomes for spine operations.

Offset layered closure reduces deep wound infection in early-onset scoliosis surgery

Deep wound infection is a common complication in early-onset scoliosis (EOS) surgery. Soft tissue technique has received less attention as a means to reduce infection. A retrospective review of 1170 EOS surgeries (single surgeon, institution) investigated the impact of offset layered closure (OLC) and soft tissue awareness. The introduction of OLC reduced deep infection from 3.0% in 99 surgeries to 0.37% in 1071. Logistic regression confirmed that OLC led to significantly lower odds of infection (P=0.007). This deep infection rate (0.37%) is more typical of elective surgery, providing a more optimistic view of infection in EOS surgery than generally reported.

Preliminary comparison of primary and conversion surgery with magnetically controlled growing rods in children with early onset scoliosis

PURPOSE

Non-invasive distraction of magnetically controlled growing rods (MCGR) avoids repeated surgical lengthening in patients with early onset scoliosis, but it is not known how effective this technique is in previously operated children.

METHODS

In a retrospective, multicentre study, the data were obtained for 27 primary (P) patients [mean age 7.0 (2.4-10.7) years at surgery] and 23 conversion (C) patients [mean age 7.7 (3.6-11.0) years at conversion from standard growing rods] with 1-year follow-up.

RESULTS

The mean major curve was 63.9° in the P group and 46.5° in the C group at baseline (preoperatively, p = 0.0009) and 39.5° and 39.6°, respectively, at 1-year follow-up (p = 0.99). The mean percentage change of spinal growth from baseline to 1-year follow-up was 18.3 % in the P group and 6.5 % in the C group (p = 0.007). Comparing the spinal growth from postoperative to 1-year follow-up no statistical difference was observed between the study groups (1.8 % P vs -2.2 % C, p = 0.09).

CONCLUSIONS

Scoliosis can be equally controlled after conversion from traditional growing rods into MCGR, but spinal growth from baseline is less in the conversion patients as compared with the primary group.

LEVEL OF EVIDENCE

III.

Variability of Surgical Site Infection With VEPTR at Eight Centers: A Retrospective Cohort Analysis

STUDY DESIGN

Retrospective review.

OBJECTIVES

To describe clinical characteristics and infection rates in modern vertical expandable prosthetic titanium rib (VEPTR) surgery.

SUMMARY OF BACKGROUND DATA

Prior studies have demonstrated infection rates from 10% to 30% with VEPTR surgery.

METHODS

A retrospective query was done on an institutional review board-approved, multicenter prospectively collected database for patients implanted with VEPTR from 2007 to 2013 at eight sites. This identified 213 patients with appropriate data for analysis. Average follow-up was 4.1 years (range 1.7-6.3). Data collected included a Classification of Early-Onset Scoliosis (C-EOS) diagnosis, American Society of Anesthesiologists Physical Status (ASA-PS), major Cobb angle, construct type, clinical symptoms, and microbiology. The distribution of infection rates across all the study sites was compared. The exact p value was estimated by Monte Carlo simulation.

RESULTS

Overall, 18% (38/213) of patients implanted with VEPTR developed infection requiring operative debridement. There were significantly different infection rates among the sites, ranging from 2.9% to 42.9% (p = .029). The average time to infection was 70 days (range 8-236) after the infecting procedure. The majority of infections were due to gram-positive bacteria (80%, 44/55), the most prevalent being methicillin-sensitive Staphylococcus aureus (45%, 25/55). There were 20 patients (53%, 20/38) with either partial or complete implant removal to resolve infection; however, only 3 of 38 (8%) of these resulted in abandonment of VEPTR treatment. There was no difference in infection rate across the primary C-EOS diagnosis categories (p = .21) or based on ASA score (p = .53). After controlling for study site, the odds ratio of an infection following an implant procedure versus an expansion was 2.8 (p = .002). There was no difference in the odds ratio of an infection between the other procedure types (implant, expansion, exchange/revision).

CONCLUSIONS

There were significant differences in infection rates between sites. The variability in infection rate indicates a need for guided efforts to standardize best practices for infection control in VEPTR surgery.

LEVEL OF EVIDENCE

III, therapeutic study.

Early-Onset Scoliosis: A Review of History, Current Treatment, and Future Directions

Early-onset scoliosis (EOS) is defined as curvature of the spine in children >10° with onset before age 10 years. Young children with EOS are at risk for impaired pulmonary function because of the high risk of progressive spinal deformity and thoracic constraints during a critical time of lung development. The treatment of EOS is very challenging because the population is inhomogeneous, often medically complex, and often needs multiple surgeries. In the past, early spinal fusion was performed in children with severe progressive EOS, which corrected scoliosis but limited spine and thoracic growth and resulted in poor pulmonary outcomes. The current goal in treatment of EOS is to maximize growth of the spine and thorax by controlling the spinal deformity, with the aim of promoting normal lung development and pulmonary function. Bracing and casting may improve on the natural history of progression of spinal deformity and are often used to delay surgical intervention or in some cases obviate surgery. Recent advances in surgical implants and techniques have led to the development of growth-friendly implants, which have replaced early spine fusion as the surgical treatment of choice. Treatment with growth-friendly implants usually requires multiple surgeries and is associated with frequent complications. However, growth-friendly spine surgery has been shown to correct spinal deformity while allowing growth of the spine and subsequently lung growth.

Special article: Update on the magnetically controlled growing rod: tips and pitfalls

Magnetically controlled growing rods (MCGR) have become an important treatment option in young patients with spinal deformities. This device allows for gradual lengthening on an outpatient setting with continuous neurological monitoring in an awake patient. With its growing popularity and interest, this study reports the tips, pitfalls, and complications of the MCGR for management of scoliosis. On 3 June 2015 at the University of Hong Kong, 32 participants from 16 regions shared their experience with MCGR. Current indications for surgery include early-onset scoliosis patients. Adolescent idiopathic scoliosis and congenital scoliosis patients have less favourable outcomes. The number of instrumented levels should be minimised, as all instrumented levels must be included in the definitive fusion surgery. Rod contouring is important and owing to the straight portion of the rod housing the magnet, there is limited proximal rod portion for proper contouring, which may predispose to proximal junctional kyphosis. There is currently no consensus on the rod configuration, timing, frequency, technique, and amount of distraction. Risk factors for distraction failure include larger patients, internal magnets too close to each other, and magnets too close to the apex of the major curve. Future studies should resolve the issues regarding the technique of distraction, optimal frequency and amount of distraction per session. More comprehensive cost analyses should be performed.

Magnetic Expansion Control System Achieves Cost Savings Compared to Traditional Growth Rods: An Economic Analysis Model

STUDY DESIGN

Medical economic model with multi-way sensitivity analysis.

OBJECTIVE

To compare the direct costs of growing rod (GR) versus Magnetic Expansion Control System (MG) from a payer's perspective. We hypothesized that over time the MG will become more cost-effective.

SUMMARY OF BACKGROUND DATA

Traditional GRs provide effective treatment, but require periodic lengthening surgery. MG allows rod lengthening in clinic, but the implant is expensive. The cumulative cost savings are not well understood.

METHODS

Index surgery, implant cost, lengthening procedure, and revision surgery due to implant failure or infection were identified as major parameters contributing to the cumulative cost. The "base," "low," and "high" values for the cost and the incidence of each parameter were determined by literature reports, health care database search, or expert consultation. The cumulative cost was compared annually during 5 years of follow-up. Marginal cost was defined as the cost of (GR-MG) for each cumulative year. Final cumulative cost and extreme case scenario at year 5 were assessed by deterministic sensitivity analysis.

RESULTS

MG resulted in higher cumulative cost at years 1 and 2, and became lower cost at years 3 through 5. The marginal cost at year 1 was a negative value of $16K, and trended toward positive values of $12K at year 3 and $40K by year 5. Sensitivity analysis revealed that in extreme case, MG could cost more, shown by a marginal cost of $26K by implementing the extreme values of the 3 parameters carrying highest variance: MG-infection management, GR-revision surgery, and GR-lengthening procedure.

CONCLUSION

MG achieved cost neutrality to GR at 3 years after index surgery. This is the first medical economic study in the United States comparing the cost of GR versus MG and demonstrates potential cost-effectiveness of MG from payer's perspective if in place for more than 3 years.

LEVEL OF EVIDENCE

2.

Risk factors for surgical site infection after posterior fixation surgery and intraoperative radiotherapy for spinal metastases

PURPOSE

Posterior surgery with intraoperative radiotherapy for spinal metastases offers effective therapy, as we have reported previously. However, the procedure involves transfer from the operating room to the radiotherapy room, and as these patients are somewhat immunocompromised, the risk of postoperative surgical site infection (SSI) may be increased. The aim of our study was to identify risk factors and patient characteristics associated with postoperative SSI following posterior fixation surgery and intraoperative radiotherapy for spinal metastases.

METHODS

Participants comprised 279 patients who underwent IORT for the treatment of spinal metastases between August 2004 and June 2013. Patients who suffered SSI within 1 month after surgery were categorized as infected, and all others were categorized as non-infected. We compared factors of age, sex, use of pre-operative corticosteroid, medical history of diabetes, prognosis scores (Tomita, Tokuhashi, and Katagiri), pre- and postoperative Frankel scale scores, site of tumor origin, administration of pre-operative radiotherapy, operation time, intraoperative blood loss, intraoperative irradiation dose, and pre- and postoperative performance status between groups.

RESULTS

SSI occurred in 41 patients (14.7%). Katagiri's and Tokuhashi's prognostic scores (P < 0.05 each), postoperative Frankel scale score (P < 0.01), administration of pre-operative radiotherapy (P < 0.05), and postoperative performance status (P < 0.05) all correlated significantly with occurrence of SSI. Multivariate analysis using those factors revealed administration of pre-operative radiotherapy as a factor independently associated with SSI (P < 0.05).

CONCLUSIONS

Patient prognosis, postoperative ambulatory function, and pre-operative radiotherapy were risk factors for SSI in patients with spinal metastases. Duration of surgery and intraoperative blood loss were not associated with occurrence of SSI.

Current Animal Models of Postoperative Spine Infection and Potential Future Advances

Implant related infection following spine surgery is a devastating complication for patients and can potentially lead to significant neurological compromise, disability, morbidity, and even mortality. This paper provides an overview of the existing animal models of postoperative spine infection and highlights the strengths and weaknesses of each model. In addition, there is discussion regarding potential modifications to these animal models to better evaluate preventative and treatment strategies for this challenging complication. Current models are effective in simulating surgical procedures but fail to evaluate infection longitudinally using multiple techniques. Potential future modifications to these models include using advanced imaging technologies to evaluate infection, use of bioluminescent bacterial species, and testing of novel treatment strategies against multiple bacterial strains. There is potential to establish a postoperative spine infection model using smaller animals, such as mice, as these would be a more cost-effective screening tool for potential therapeutic interventions.

Risk factors for surgical site infection following pediatric spinal deformity surgery: a systematic review and meta-analysis

PURPOSE

This study was conducted to identify risk factors for postoperative infection after pediatric spinal deformity surgery.

METHODS

A systematic electronic literature search from inception to November 2014 was performed in the following databases: Pubmed, Embase, and Cochrane library databases. Pooled odds ratios (ORs) or standardized mean differences (SMDs) with 95 % confidence intervals (CIs) were calculated using random or fixed effects model. Newcastle-Ottawa scale was used to evaluate the methodological quality, and Stata 11.0 was used to analyze data.

RESULTS

The main factors associated with infection after spinal surgery were idiopathic scoliosis (OR, 0.303; 95 % CI, 0.202-0.453), neuromuscular scoliosis (OR, 2.269; 95 % CI, 1.576-3.267), ambulatory status (OR, 0.241; 95 % CI, 0.078-0.747), previous spinal surgery (OR, 4.564; 95 % CI, 1.892-11.009), sacral vertebrae fused (OR, 2.717; 95 % CI, 1.836-4.020), and allograft (OR, 8.498; 95 % CI, 4.030-17.917). There was no sufficient evidence to reveal that male gender, age, body mass index, preoperative curve, preoperative urinary tract infection, combined anterior-posterior approach, estimated blood loss, and operating room time could lead to infection after spinal surgery.

CONCLUSIONS

We identified some risk factors which could be used to prevent the onset of surgical site infection in pediatric spinal deformity surgery. However, the results of this meta-analysis should be interpreted with caution because of the heterogeneity among the studies.