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

Instrumentation failure following pediatric spine deformity growth-sparing surgery using traditional growing rods or vertical expandable prosthetic titanium ribs

BACKGROUND

Instrumentation failure (IF) is a major complication associated with growth-sparing surgery for pediatric spinal deformities; however, studies focusing on IF following each surgical procedure are lacking. We aimed to evaluate the incidence, timing, and rates of unplanned return to the operating room (UPROR) associated with IF following each surgical procedure in growth-sparing surgeries using traditional growing rods (TGRs) and vertical expandable prosthetic titanium ribs (VEPTRs).

METHODS

We reviewed 1,139 surgical procedures documented in a Japanese multicenter database from 2015 to 2017. Of these, 544 TGR and 455 VEPTR procedures were included for evaluation on a per-surgery basis. IF was defined as the occurrence of an implant-related complication requiring revision surgery.

RESULTS

The surgery-based incidences of IF requiring revision surgery in the TGR and VEPTR groups were 4.3% and 4.0%, respectively, with no significant intergroup difference. Remarkably, there was a negative correlation between IF incidence per surgical procedure and the number of lengthening surgeries in both groups. In addition, rod breakage in the TGR group and anchor-related complications in the VEPTR group tended to occur relatively early in the treatment course. The surgery-based rates of UPROR due to IF in the TGR and VEPTR groups were 2.0% and 1.5%, respectively, showing no statistically significant difference.

CONCLUSIONS

We found that IF, such as anchor related-complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries. This finding may help in patient counseling and highlights the importance of close postoperative follow-up to detect IF and improve outcomes.

Intraoperative Antibiotic Use in Patients With Early-onset Scoliosis: Current Practices and Trends

BACKGROUND

Best Practice Guidelines (BPGs) regarding antibiotic prophylaxis in early-onset scoliosis (EOS) patients were published in September 2019. Recommendations included using intravenous cefazolin and topical vancomycin for all index procedures, plus gram-negative coverage for neuromuscular patients. Guideline adherence is unknown. This study aimed to characterize antibiotic prophylaxis at the time of index growth-friendly procedures and assess changes in practice patterns over time.

MATERIALS AND METHODS

This retrospective review of data collected through a multicenter study group included EOS patients undergoing index growth-friendly procedures between January 2018 and March 2021, excluding revisions, lengthenings, and tetherings. Demographics, clinical measurements, intraoperative antibiotics, and 90-day complications were recorded. Descriptive and univariate statistics were utilized. Antibiotic prophylaxis from April 2018 through September 2019 and October 2019 through March 2021 were compared with evaluate change after BPG publication.

RESULTS

A total of 562 patients undergoing growth-friendly procedures were included. The most common scoliosis types included neuromuscular (167, 29.7%), syndromic (134, 23.8%), and congenital (97, 17.3%). Most index procedures involved magnetically controlled growing rods (417, 74%) followed by vertical expandable prosthetic titanium rib or traditional growing rods (105, 19%). Most patients received cefazolin alone at index procedure (310, 55.2%) or cefazolin with an aminoglycoside (113, 20.1%). Topical antibiotics were used in 327 patients (58.2%), with most receiving vancomycin powder. There was increased use of cefazolin with an aminoglycoside after BPG publication (16% vs. 25%) ( P =0.01). Surgical site infections occurred in 12 patients (2.1%) within 90 days of index procedure, 10 pre-BPGs (3%), and 2 post-BPGs (0.9%), with no significant difference in surgical site infection rate by type of antibiotic administered ( P >0.05).

CONCLUSIONS

Historical variability exists regarding antibiotic prophylaxis during index growth-friendly procedures for EOS. There continues to be variability following BPG publication; however, this study found a significant increase in antibiotic prophylaxis against gram-negative bacteria after BPG publication. Overall, greater emphasis is needed to decrease variability in practice, improve compliance with consensus guidelines, and evaluate BPG efficacy.

LEVEL OF EVIDENCE

Level III-retrospective.

Surgical Treatment of Spinal Deformities in Pediatric Orthopedic Patients

Scoliosis and Scheuermann's disease are common spinal deformities that affect a substantial population, particularly adolescents, often impacting their quality of life. This comprehensive review aims to present a detailed understanding of these conditions, their diagnosis, and various treatment strategies. Through an extensive exploration of current literature, the review discusses the etiology of these spinal deformities and the use of diagnostic tools such as X-rays and MRI. It further delves into the range of treatment options available, from conservative approaches such as physiotherapy and bracing to more invasive surgical interventions. The review underscores the necessity of an individualized treatment approach, taking into account factors such as the patient's age, the severity of the curvature, and overall health. This all-encompassing perspective on scoliosis and Scheuermann's disease will aid in evidence-based decision making in their management with the goal of improving patient outcomes.

Risk factors of early complications after thoracic and lumbar spinal deformity surgery: a systematic review and meta-analysis

PURPOSE

To determine risk factors increasing susceptibility to early complications (intraoperative and postoperative within 6 weeks) associated with surgery to correct thoracic and lumbar spinal deformity.

METHODS

We systematically searched the PubMed and EMBASE databases for studies published between January 1990 and September 2021. Observational studies evaluating predictors of early complications of thoracic and lumbar spinal deformity surgery were included. Pooled odds ratio (OR) or standardized mean difference (SMD) with 95% confidence intervals (CI) was calculated via the random effects model.

RESULTS

Fifty-two studies representing 102,432 patients met the inclusion criteria. Statistically significant patient-related risk factors for early complications included neurological comorbidity (OR = 3.45, 95% CI 1.83-6.50), non-ambulatory status (OR = 3.37, 95% CI 1.96-5.77), kidney disease (OR = 2.80, 95% CI 1.80-4.36), American Society of Anesthesiologists score > 2 (OR = 2.23, 95% CI 1.76-2.84), previous spine surgery (OR = 1.98, 95% CI 1.41-2.77), pulmonary comorbidity (OR = 1.94, 95% CI 1.21-3.09), osteoporosis (OR = 1.60, 95% CI 1.17-2.20), cardiovascular diseases (OR = 1.46, 95% CI 1.20-1.78), hypertension (OR = 1.37, 95% CI 1.23-1.52), diabetes mellitus (OR = 1.84, 95% CI 1.30-2.60), preoperative Cobb angle (SMD = 0.43, 95% CI 0.29, 0.57), number of comorbidities (SMD = 0.41, 95% CI 0.12, 0.70), and preoperative lumbar lordotic angle (SMD = - 0.20, 95% CI - 0.35, - 0.06). Statistically significant procedure-related factors were fusion extending to the sacrum or pelvis (OR = 2.53, 95% CI 1.53-4.16), use of osteotomy (OR = 1.60, 95% CI 1.12-2.29), longer operation duration (SMD = 0.72, 95% CI 0.05, 1.40), estimated blood loss (SMD = 0.46, 95% CI 0.07, 0.85), and number of levels fused (SMD = 0.37, 95% CI 0.03, 0.70).

CONCLUSION

These data may contribute to development of a systematic approach aimed at improving quality-of-life and reducing complications in high-risk patients.

Definitive fusions are better than growing rod procedures for juvenile patients with cerebral palsy and scoliosis: a prospective comparative cohort study

PURPOSE

This study compared the outcomes of juvenile patients with cerebral palsy (CP) and scoliosis who underwent spinal fusion (SF) versus growing rod (GR) surgery.

METHODS

Two prospective multicenter registries were queried for patients 8-10 years old with minimum 2-year follow-up who underwent SF or GR surgery (no MCGR). Demographics, radiographs, complications, and outcome scores were recorded.

RESULTS

There were 35 patients in the SF and 15 in the GR group. The mean age at surgery was 10 and 9.3 years in the SF and GR groups, respectively (p = 0.004). In the SF group preoperatively, the major curve measured 86° and 80° in the GR group (p = 0.40). "Definitive" surgery in the GR group consisted of SF in 10, implant retention in three, and implant removal in two. The SF group had 60.8% and the GR group had 45.0% correction following "definitive" surgery (p = 0.03). In the SF group, 8 patients and in the GR group, 9 patients (SF = 22.9%, GR = 60.0%) had a complication (p = 0.01). In the SF group, two patients (5.7%) had reoperations for infection; eight patients (53.3%) in the GR group had reoperations for infection and implant complications (p < 0.001). In the SF group, 23/30 parents (76.6%) noted that the child's life "improved a lot." In the GR group, 3/6 parents (50.0%) noted they were "neutral" about their child's ability to do things, 2/6 (33.3%) were "very dissatisfied."

CONCLUSIONS

SF treatment for juvenile patients with CP and scoliosis resulted in fewer complications and unplanned reoperations and better radiographic outcomes compared with GR. Quality of life improvements were also better in the SF group.

LEVEL OF EVIDENCE

Level III.

Surgical Site Infections after Spinal Surgery in a Tropical Area: A Prospective Monocentric Observational Study

To date, no study has described the microbiological profile of surgical site infections (SSIs) after spine surgery in a tropical environment. The main objective of this study is to describe the microbiology and the risk factors of SSI after spinal surgery in a tropical climate. Our hypothesis is that the microbiology of SSIs in tropical areas is different to what is mainly described in temperate countries. As a consequence, the recommendation for antibiotic prophylaxis administered in the operative room, which mainly relays on the literature, might not be adequate in such countries. We included 323 consecutive patients who underwent a spinal intervention between 2017 and 2019, with a 2-year minimum follow-up. Objective ISO criteria were established in accordance with the criteria accepted by the Center of Disease Control in Atlanta. The identification of risk factors for SSI was carried out by uni- and multivariate analysis with a significance threshold of P < 0.05. The incidence of SSI was 7.7%. A total of 54.8% were in favor of a predominantly digestive origin of germs with an average of 1.68 bacteria found by ISO. Inadequate antibiotic prophylaxis was found in 54.8%. Age and body mass index were found to be independent risk factors for SSI. We report here an unusual microbiological profile of SSI with a predominance of gram-negative bacteria and a low proportion of Staphylococcus aureus and Staphylococcus epidermidis.

Unmatched rod contouring at the proximal end predisposes to occurrence of junctional kyphosis in early-onset scoliosis patients undergoing traditional growing rods treatment

STUDY DESIGN

A retrospective case series.

OBJECTIVE

To investigate whether unmatched rod contouring at the proximal end predisposed to the occurrence of proximal junctional kyphosis (PJK) in early-onset scoliosis (EOS) patients after traditional growing rods (TGR) treatment. TGR treatment has become a mainstay of treatment for EOS patients. PJK is one of the most common alignment-related complications.

METHODS

A consecutive series of EOS patients who had undergone TGR treatment were retrospectively reviewed. They were divided into PJK and non-PJK groups according to the occurrence of PJK or not. Demographic data, surgical strategies, and radiographic parameters were recorded and compared between groups. Proximal junctional angle (PJA) was defined as the angle between the caudal endplate of the UIV and the cephalad endplate of the second supradjacent vertebra above the UIV, while proximal rod contouring angle (PRCA) was defined as the angle of proximal rod contouring, which was represented by the angle between the cephalad endplate of the UIV and the caudal endplate of the second vertebra caudal to the UIV. Unmatched proximal rod contouring was regarded if the postoperative PRCA-PJA difference was greater than 5°.

RESULTS

This study finally included 73 patients. The mean age at the index surgery was 6.5 ± 2.2 years (range, 2-10 years). Mean follow-up lasted 5.0 ± 1.7 years (range, 2-9 years). They received mean 4.6 ± 1.6 lengthening procedures. There were 13 patients who were observed with PJK (18%). In comparison with the non-PJK group, the PJK group showed a larger preoperative major curve (82 ± 21° vs 70 ± 17°, P = 0.041) and global kyphosis (57 ± 6° vs. 44 ± 15°, P = 0.044). In addition, the PJK group had significantly larger postoperative PJA (10 ± 3 vs. 5 ± 3, P<0.001) and greater postoperative PJA-PRCA (6 ± 3 vs. 3 ± 3, P = 0.031). The proportion of patients with unmatched proximal rod contouring in PJK group was significantly higher than that in the non-PJK group (69% vs. 25%). Multiple logistic regression showed that preoperative GK>50°, postoperative PJA>10 and postoperative unmatched proximal rod contouring were the risk factors in predicting PJK after TGR treatment.

CONCLUSION

Approximately 18% EOS patients experienced PJK after TGR treatment. Unmatched proximal rod contouring may be an independent risk factor of PJK occurrence, in addition to greater preoperative GK and larger postoperative PJA.

LEVEL OF EVIDENCE: 3

Wound-Related Complication in Growth-Friendly Spinal Surgeries for Early-Onset Scoliosis-Literature Review

Background: The treatment for early-onset scoliosis (EOS) is one of the most challenging for pediatric orthopedics. Surgical treatment is often necessary, and wound problems and surgical site infections (SSIs) are common, with potentially severe complications in these patients. The aim of the study was to review current literature according to this complication. Methods: PubMed, Cochrane Library, and Embase were systematically searched for relevant articles by two independent reviewers in January 2022. Every step of the review was done according to PRISMA guidelines. Results: A total of 3579 articles were found. Twenty four articles were included in this systematic review after applying our inclusion and exclusion criteria. EOS surgery has a varying but high rate of wound-related problems (on average, 15.5%). Conclusion: The literature concerning the definitions, collection, and interpretation of data regarding EOS wound-related complications is often difficult to interpret. This causes problems in the comparison and analysis. Additionally, this observation indicates that data on the incidence of SSI may be underestimated. Awareness of the high rate of SSI of EOS surgery is crucial, and an optimal strategy for prevention should become a priority.

Animal Models for Postoperative Implant‐Related Spinal Infection

Postoperative infections following implant‐related spinal surgery are severe and disastrous complications for both orthopaedic surgeons and patients worldwide. They can cause neurological damage, disability, and death. To better understand the mechanism of these destructive complications and intervene in the process, further research is needed. Therefore, there is an urgent need for efficient, accurate, and easily available animal models to study the pathogenesis of spinal infections and develop new and effective anti‐bacterial methods. In this paper, we provide a general review of the commonly used animal models of postoperative implant‐related spinal infections, describe their advantages and disadvantages, and highlight the significance of correctly choosing the model according to the infection aspect under investigation. These models are valuable tools contributing to the better understanding of postoperative spinal infections and will continue to facilitate the invention of novel preventative and treatment strategies for patients with postoperative spinal infections. However, although they are valid and reproducible in some respects, the current animal models present certain limitations. Future ideal spinal infection animal models may assess the bacterial load of the same animal in real‐time in vivo, and better mimic the human anatomy as well as surgical techniques. Strains other than Staphylococcus aureus account for a large proportion of postoperative spinal infections, and thus, the establishment of models to evaluate other types of microbial infections is expected in the future. Furthermore, novel transgenic models established on advancements in genome editing are also likely to be developed in the future.

Surgical site infections in early onset scoliosis: what are long-term outcomes in patients with traditional growing rods?

PURPOSE

Deep surgical site infections (SSIs) are a common and potentially severe complication in early onset scoliosis (EOS) patients. We sought to identify the long-term outcomes following SSI, specific risk factors associated with recurrent infections, and if instrument retention is a prudent SSI management strategy in EOS.

METHODS

We performed a retrospective review of all EOS patients who underwent traditional growing rod spine procedures from 2003 to 2017. Infections were categorized as single or multiple SSIs. All infections were treated with operative irrigation and debridement (I&D) as well as antibiotics. Univariate analysis was performed using chi-square and ANOVA tests to assess differing factors between patients with single versus multiple infections.

RESULTS

Eighty-one patients underwent 638 growth-friendly traditional growing rod procedures. There were 21 patients (26%) who developed a total of 27 SSIs (4.2% SSI per procedure). Fifteen patients had a single infection and six patients had multiple infections. Demographics were not significantly different between these two groups. Patients with multiple infections had a significant difference in the number of procedures after initial infection (p value = 0.025) and positive preoperative nasal Staphylococcus aureus screen (p value = 0.0021) when compared to those with a single SSI. Of note, these results were not available at the time of pre-operative antibiotic selection. All 21 patients had resolution of their SSIs. Twenty patients reached final instrumented fusion. Two patients, both of whom had multiple infections, underwent complete removal of instrumentation. Reasons included one each, parental request resulting in termination of treatment and infection > 7 years after final fusion.

CONCLUSION

Most patients who develop SSIs during growing spine treatment are able to remain instrumented. Risk factors associated with developing multiple SSIs include infection earlier in the course of growing spine surgery, a resultant higher number of procedures following the initial infection and having a positive preoperative nasal Staphylococcus aureus screen.

LEVEL OF EVIDENCE

IV.

A Clinical Risk Model for Surgical Site Infection Following Pediatric Spine Deformity Surgery

BACKGROUND

Despite tremendous efforts, the incidence of surgical site infection (SSI) following the surgical treatment of pediatric spinal deformity remains a concern. Although previous studies have reported some risk factors for SSI, these studies have been limited by not being able to investigate multiple risk factors at the same time. The aim of the present study was to evaluate a wide range of preoperative and intraoperative factors in predicting SSI and to develop and validate a prediction model that quantifies the risk of SSI for individual pediatric spinal deformity patients.

METHODS

Pediatric patients with spinal deformity who underwent primary, revision, or definitive spinal fusion at 1 of 7 institutions were included. Candidate predictors were known preoperatively and were not modifiable in most cases; these included 31 patient, 12 surgical, and 4 hospital factors. The Centers for Disease Control and Prevention definition of SSI within 90 days of surgery was utilized. Following multiple imputation and multicollinearity testing, predictor selection was conducted with use of logistic regression to develop multiple models. The data set was randomly split into training and testing sets, and fivefold cross-validation was performed to compare discrimination, calibration, and overfitting of each model and to determine the final model. A risk probability calculator and a mobile device application were developed from the model in order to calculate the probability of SSI in individual patients.

RESULTS

A total of 3,092 spinal deformity surgeries were included, in which there were 132 cases of SSI (4.3%). The final model achieved adequate discrimination (area under the receiver operating characteristic curve: 0.76), as well as calibration and no overfitting. Predictors included in the model were nonambulatory status, neuromuscular etiology, pelvic instrumentation, procedure time ≥7 hours, American Society of Anesthesiologists grade >2, revision procedure, hospital spine surgical cases <100/year, abnormal hemoglobin level, and overweight or obese body mass index.

CONCLUSIONS

The risk probability calculator encompassing patient, surgical, and hospital factors developed in the present study predicts the probability of 90-day SSI in pediatric spinal deformity surgery. This validated calculator can be utilized to improve informed consent and shared decision-making and may allow the deployment of additional resources and strategies selectively in high-risk patients.

LEVEL OF EVIDENCE

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

The Effect of Surgeon Experience on Outcomes Following Growth Friendly Instrumentation for Early Onset Scoliosis

BACKGROUND

The purpose of this study was to utilize a multicenter, multisurgeon cohort to assess the effect of surgeon experience on outcomes of growth friendly instrumentation (GFI) in early onset scoliosis (EOS). We hypothesized that unplanned return to the operating room (UPROR), estimated blood loss (EBL), and surgical time would be greater amongst early career surgeons (ECSs) when compared with advanced career surgeons (ACSs).

METHODS

An international pediatric spine database was queried for patients ages 2 to 10 years treated by posterior distraction-based GFI with at least of 2-year follow up. Two groups were created for analysis based on surgeon experience: ECSs (with ≤10 y of experience) and ACSs (with >10 y of experience). The primary outcome was UPROR. Additional outcomes included: operating room time, EBL, neurological deficits, infection rate, hardware failure, and the Early Onset Scoliosis Questionnaire (EOSQ-24). Subgroup analysis was performed for further assessment based on procedure type, superior anchor type, etiology, and curve severity.

RESULTS

A total of 960 patients met inclusion criteria including 243 (25.3%) treated by ECS. Etiology, sex, superior anchor, and EOSQ-24 scores were similar between groups (P>0.05). There were no clinically significant differences in patient age or preoperative major coronal curve. UPROR (35.8% vs. 32.7%, P=0.532), infection (17.0% vs. 15.6%, P=0.698), operating room time (235 vs. 231 min, P=0.755), and EBL (151 vs. 155 mL, P=0.833) were comparable between ECS and ACS groups. The frequency of having at least 1 complication was relatively high but comparable among groups (60.7% vs. 62.6%, P=0.709). EOSQ-24 subdomain scores were similar between groups at 2-year follow-up (P>0.05). Subgroup analysis revealed that ECS had increased surgical time compared with ACS in severe curves >90 degrees (270 vs. 229 min, P=0.05).

CONCLUSIONS

This study represents the first multicenter assessment of surgeon experience on outcomes in EOS. Overall, surgeon experience did not significantly influence UPROR, complication rates, EBL, or surgical time associated with GFI in this cohort of EOS patients.

LEVEL OF EVIDENCE

Level III.

A comparison of the post-fusion outcome of patients with early-onset scoliosis treated with traditional and magnetically controlled growing rods

AIMS

The aim of this study was to compare the clinical and radiological outcomes of patients with early-onset scoliosis (EOS), who had undergone spinal fusion after distraction-based spinal growth modulation using either traditional growing rods (TGRs) or magnetically controlled growing rods (MCGRs).

METHODS

We undertook a retrospective review of skeletally mature patients who had undergone fusion for an EOS, which had been previously treated using either TGRs or MCGRs. Measured outcomes included sequential coronal T1 to S1 height and major curve (Cobb) angle on plain radiographs and any complications requiring unplanned surgery before final fusion.

RESULTS

We reviewed 43 patients (63% female) with a mean age of 6.4 years (SD 2.6) at the index procedure, and 12.2 years (SD 2.2) at final fusion. Their mean follow-up was 8.1 years (SD 3.4). A total of 16 patients were treated with MCGRs and 27 with TGRs. The mean number of distractions was 7.5 in the MCGR group and ten in the TGR group (p = 0.471). The mean interval between distractions was 3.4 months in the MCGR group and 8.6 months in the TGR group (p < 0.001). The mean Cobb angle had improved by 25.1° in the MCGR group and 23.2° in TGR group (p = 0.664) at final follow-up. The mean coronal T1 to S1 height had increased by 16% in the MCGR group and 32.9% in TGR group (p = 0.001), although the mean T1 to S1 height achieved at final follow-up was similar in both. Unplanned operations were needed in 43.8% of the MCGR group and 51.2% of TGR group (p = 0.422).

CONCLUSION

In this retrospective, single-centre review, there were no significant differences in major curve correction or gain in spinal height at fusion. Although the number of planned procedures were fewer in patients with MCGRs, the rates of implant-related complications needing unplanned revision surgery were similar in the two groups. Cite this article: Bone Joint J 2022;104-B(2):257-264.

Baclofen Pump Use: Complications After Growth-friendly Instrumentation for Early-onset Scoliosis

BACKGROUND

Patients with early-onset scoliosis (EOS) and spasticity may receive treatment with an intrathecal baclofen pump. We assessed how baclofen pumps are associated with the odds of complications and secondary interventions after growth-friendly (GF) spine surgery for EOS and analyzed infectious complications within the pump cohort.

METHODS

Using a prospectively maintained, international multicenter database, we studied patients with neuromuscular EOS with baclofen pumps who underwent GF spine surgery from 2002 through 2019 (n=25). Baclofen pumps were implanted before GF instrumentation in 18 patients, during in 2 patients, and after in 5 patients. Patients with existing pumps at initial GF spine surgery were matched 1:3 with 54 patients (control group) without pumps according to treatment center, year of surgery, diagnosis, surgery type, and preoperative curve magnitude. Univariate analysis and multivariate logistic regression were performed to compare complications and secondary interventions between the 2 cohorts.

RESULTS

Patients with baclofen pumps had 4.8 times the odds [95% confidence interval (CI): 1.5-16] of experiencing any complication within 1 year after initial GF spine surgery compared with controls. During mean follow-up of 6.9±4.3 years, they had 4.7 times the odds (95% CI: 1.3-16) of deep surgical site infection and 5.6 times the odds (95% CI: 1.2-26) of spinal rod removal after any complication. Differences in rates of mechanical complication, such as rod migration and breakage, were nonsignificant between the 2 groups. For the 9 patients (50%) with pumps who experienced infections, the most common microorganisms were Staphylococcus aureus (4 patients) and Pseudomonas aeruginosa (2). The pump/catheter was revised or removed, in addition to antibiotic therapy or surgical irrigation and debridement, in 2 patients.

CONCLUSIONS

Among patients with neuromuscular EOS, those with baclofen pumps are much more likely to experience complications within 1 year after GF spine surgery. They are also more likely to have deep surgical site infections, with S. aureus and P. aeruginosa being the most common causative organisms, and to require spinal rod removal.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Matched Comparison of Magnetically Controlled Growing Rods with Traditional Growing Rods in Severe Early-Onset Scoliosis of ≥90°: An Interim Report on Outcomes 2 Years After Treatment

BACKGROUND

Severe early-onset scoliosis (EOS) is managed surgically but represents a challenge due to limited implant fixation points, large curve size, and fragile patients with comorbidities. Magnetically controlled growing rods (MCGRs) have the advantage of avoiding surgical intervention for routine lengthening, but their ability to address severe EOS has not been studied, to our knowledge.

METHODS

A retrospective review of a prospectively collected international database identified 44 children with severe (≥90°) EOS treated with MCGRs who met our study criteria. Etiology, age, and sex-matched patients treated with traditional growing rods (TGRs) were identified from the same database. Patients were evaluated at a 2-year follow-up. No patients with vertically expandable prosthetic titanium ribs (VEPTRs) were included. The health-related quality of life was evaluated with the 24-Item Early Onset Scoliosis Questionnaire (EOSQ-24).

RESULTS

The mean preoperative major coronal curve was 104° in the MCGR group and 104° in the TGR group. At the 2-year follow-up, the mean major coronal curves were 52° and 66° (p = 0.001), respectively. The mean T1-T12 heights were 155 mm and 152 mm preoperatively and 202 mm and 192 mm at the 2-year follow-up (p = 0.088). According to Kaplan-Meier analysis, the 2-year unplanned-revision-free survival was 91% in the MCGR group and 71% in the TGR group (p < 0.005). The 2-year score in the EOSQ-24 pulmonary function domain was better in the MCGR group. There were no other significant differences in the EOSQ-24 scores between the groups.

CONCLUSIONS

MCGRs for severe EOS provided significantly better major curve correction with significantly fewer unplanned revisions than TGRs at a 2-year follow-up.

LEVEL OF EVIDENCE

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

How much does depth matter? Magnetically controlled growing rod distraction directly influenced by rod tissue depth

PURPOSE

Magnetically controlled growing rod (MCGR) for the treatment of early-onset scoliosis (EOS) is a relatively innovative technique. MCGR benefits over traditional growing rods are known but limitations and complications are being revealed. The purpose of this study was to examine the importance of tissue depth on rod lengthening.

METHODS

A single-institution retrospective review of 72 MCGR patients was performed. Ultrasound measured rod distraction. Differences in programmed and actual distraction, and complications were recorded. Tissue depths and achieved length were averaged and used to construct a regression to account for variability.

RESULTS

Percentage of std and offset orientation rod lengthening relative to the programmed distraction was inversely proportional to rod depth (std R = 0.50, p = 0.002) (offset R = 0.60, p < 0.001). Expected std rod lengthening achieved decreased by 1.46%/mm depth. Expected offset rod lengthening achieved decreased by 1.68%/mm depth. 28 pts (38.9%) sustained complications. Age, sex, BMI, standard tissue depth, and/or offset tissue depth had no predictive ability with respect to complications sustained (overall model R = 0.31, p = 0.36).

CONCLUSION

In a series of EOS surgical patients treated with MCGRs, the relationship between percentage of programmed lengthening achieved as well as total lengthening was inversely proportional to tissue depth of the rod. There was a trend towards increasing frequency of complications recorded with decreasing tissue depth though this was not significant. These data can help with surgical planning during MCGR placement.

When Is a Growth-friendly Strategy Warranted? A Matched Comparison of Growing Rods Versus Primary Posterior Spinal Fusion in Juveniles With Early-onset Scoliosis

BACKGROUND

In 7 to 11-year-old juveniles with severe early-onset scoliosis (EOS) the optimal surgical option remains uncertain. This study compares growing rods (GRs) followed by definitive posterior spinal fusion (PSF) versus primary PSF in this population. We hypothesized that the thoracic height afforded by GRs would be offset by increased rigidity, more complications, and more operations.

METHODS

This retrospective comparative study included EOS patients aged 7.0 to 11.9 years at index surgery treated with GR→PSF or primary PSF during 2013 to 2020. Primary outcomes were thoracic height gain (ΔT1-12H), major curve, complications, and total operations. Primary PSFs were matched with replacement 1-to-n to GR→PSFs by age at index, etiology, and major curve.

RESULTS

Twenty-eight GR→PSFs met criteria: 19 magnetically controlled GRs and 9 traditional GRs. Three magnetically controlled GRs were definitively explanted without PSF due to complications. The remaining 25 GR→PSFs were matched to 17 primary PSFs with 100% etiology match, mean Δ major curve 1 degree, and mean Δ age at index 0.5 years (PSFs older). Median ΔT1-12H pre-GR to post-PSF was 4.7 cm with median deformity correction of 37%. Median ΔT1-12H among primary PSFs was 1.9 cm with median deformity correction of 62%. GR→PSFs had mean 1.8 complications and 3.4 operations. Primary PSFs had mean 0.5 complications and 1.3 operations. Matched analysis showed adjusted mean differences of 2.3 cm greater ΔT1-12H among GR→PSFs than their matched primary PSFs, with 25% less overall coronal deformity correction, 1.2 additional complications, and 2.2 additional operations per patient.

CONCLUSIONS

In juveniles aged 7 to 11 with EOS, on average GRs afford 2 cm of thoracic height over primary PSF at the cost of poorer deformity correction and additional complications and operations. Primary PSF affords an average of 2 cm of thoracic height gain; if an additional 2 cm will be impactful then GRs should be considered. However, in most juveniles the height gained may not warrant the iatrogenic stiffness, complications, and additional operations. Surgeons and families should weigh these benefits and harms when choosing a treatment plan.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Postoperative Management Strategy of Surgical Site Infection following Lumbar Dynesys Dynamic Internal Fixation

Aim

To research the incidence of surgical site infection (SSI) following lumbar Dynesys dynamic internal fixation and its management strategy.

Methods

We retrospectively analyzed all cases of lumbar Dynesys dynamic internal fixation performed from January 2010 to December 2019, and the data from patients with SSI were collected. The observational indicators included the incidence of SSI, general information of the patients, surgical details, inflammatory indicators, pathogenic bacteria, and treatment. SSI was defined as both early infection and delayed infection, and the cases were divided into Groups A and B, respectively. The relevant indicators and treatment were compared between the two groups.

Results

A total of 1125 cases of lumbar Dynesys dynamic internal fixation were followed up. Twenty-five cases of SSI occurred, and the incidence of SSI was 2.22% (25/1125). There were 14 cases of early infection (1.24%) and 11 cases of delayed infection (0.98%). Fourteen cases of early infection occurred 12.3 ± 8.3 days postoperatively (3–30), and 11 cases of delayed infection occurred 33.3 ± 18.9 months postoperatively (3–62). The inflammatory indicators of Group A were significantly higher than those of Group B (all P < 0.05), except for procalcitonin. The main infection site in Group A was located on the skin and subcutaneous tissue and around the internal instrument, while the main infection site in Group B was around the internal instrument. The main treatment for Group A was debridement and implant replacement, and the main treatment for Group B was implant removal. Summary. The incidence of SSI following lumbar Dynesys dynamic internal fixation was 2.22%, the incidence of early SSI was 1.24%, and the incidence of delayed SSI was 0.98%. If the main infection site of early infection is in the incision, debridement should be the main treatment method; if the infection site is around the internal fixation, implant replacement is recommended on the basis of debridement. Once delayed infection is diagnosed, implant removal is suggested.

Pulmonary function and health-related quality of life in patients with early onset scoliosis after repeated traditional growing rod procedures

PURPOSE

The purpose of this study was to investigate pulmonary function and health-related quality of life after traditional growing rod (TGR) procedures.

METHODS

Between January 2006 and December 2017, a retrospective observational study of 17 early onset scoliosis (EOS) patients with a mean follow-up of 6.2 years (2.3 to 10.4) was conducted. The forced expiratory volume in one second (FEV₁), expiratory forced vital capacity (FVC) and 24-Item Early Onset Scoliosis Questionnaire (EOSQ-24) score before the index surgery and at last follow-up were investigated.

RESULTS

The mean percentage of predicted FEV₁ improved from 50% (20% to 86%) to 53% (15% to 80%; p = 0.08); and the mean percentage of predicted FVC improved from 51% (24% to 81%) to 55% (25% to 89%; p = 0.06). The mean EOSQ-24 score was 78.2 (58 to 90) preoperatively and 77.2 (55 to 88) at last follow-up, there was no statistical difference (p = 0.70). The subdomain scores of pulmonary function (p < 0.01) and daily living (p < 0.01) significantly improved, whereas the subdomain scores of pain (p < 0.01), emotion (p < 0.01) and satisfaction (p = 0.02) significantly declined at last follow-up.

CONCLUSION

The TGR procedure was associated with stable pulmonary function and decline in EOSQ-24 pain, emotion and satisfaction scores.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Use of Vancomycin Powder in the Surgical Treatment of Early Onset Scoliosis Is Associated With Different Microbiology Cultures After Surgical Site Infection

BACKGROUND

The use of vancomycin powder has been shown to decrease risk of surgical site infection (SSI) in early onset scoliosis (EOS). While there is potential benefit in SSI reduction, there is also theoretical risk in creating increased bacterial resistance to standard treatment regimens. However, the effects of topical vancomycin powder on microbiology in these patients has not been studied.

METHODS

A multicenter database for EOS patients was retrospectively analyzed. All patients that underwent surgical treatment with traditional growing rods, magnetically controlled growing rods, vertical expandable prosthetic titanium rib, and Shilla for EOS performed after 2010 were identified (n=1115). Patients that sustained at least 1 SSI after guided growth surgery were assessed (n=104, 9.3%). Patients with culture and antibiotic details were included (n=55). Patients that received vancomycin powder at index surgery were compared with patients that did not. A multivariate regression model was used to control for potential confounders.

RESULTS

There were 55 patients included in this study, including 26 males (47%) and 29 females (53%). Mean age at index surgery was 7.2±6.9 years. Vancomycin powder was utilized in 18 cases (33%). Mean time from index surgery to SSI was 2.0±1.3 years. There were 2 cases of wound dehiscence (4%), 7 cases of superficial infection (13%), and 46 cases of deep infection (84%).There were significant differences in overall microbiology results between vancomycin and no vancomycin cohorts (P=0.047). On univariate analysis, the vancomycin powder cohort had a significantly high incidence of cultures without growth (n=7, 39% vs. n=4, 11%, relative risk: 2.063, 95% confidence interval: 0.927-4.591, P=0.028). This association remained significant on multivariate analysis (adjusted odds ratio: 9.656, 95% confidence interval: 1.743-53.494, P=0.009).

CONCLUSIONS

In EOS patients undergoing procedures complicated by SSI, the use of vancomycin powder was independently associated with increased risk of no culture growth. Surgeons and infectious disease physicians should be aware and adjust diagnostic and treatment strategies appropriately.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Outcomes and Complications in Management of Congenital Myopathy Early-Onset Scoliosis

BACKGROUND

Congenital myopathies (CMs) are complex conditions often associated with early-onset scoliosis (EOS). The purpose of this study was to investigate radiographic outcomes in CM patients undergoing EOS instrumentation as well as complications. Secondarily, we sought to compare these patients to a population with higher prevalence, cerebral palsy (CP) EOS patients.

METHODS

This is a retrospective study of a prospectively collected multicenter registry. The registry was queried for EOS patients with growth-sparing instrumentation (vertical expandable prosthetic titanium ribs, magnetically controlled growing rods, traditional growing rod, or Shilla) and a CM or CP diagnosis with minimum 2 years follow-up. Outcomes included major curve magnitude, T1-S1 height, kyphosis, and complications.

RESULTS

Sixteen patients with CM were included. Six (37.5%) children with CM experienced 11 complications by 2 years. Mean major curve magnitude for CM patients was improved postoperatively and maintained at 2 years (P<0.01), with no significant increase in T1-S1 height or maximum kyphosis(P>0.05). Ninety-seven patients with CP EOS were included as a comparative cohort. Fewer CP patients required baseline respiratory support compared with CM patients (20.0% vs. 92.9%, P<0.01). Fifty-four (55.7%) CP patients experienced a total of 105 complications at 2 years. There was no evidence that the risk of complication or radiographic outcomes differs between cohorts at 2 years, though CP EOS patients experienced significant improvement in all measurements at 2 years.

CONCLUSIONS

EOS CM children face a high risk of complication after growing instrumentation, with similar curve correction and risk of complication to CP patients.

LEVEL OF EVIDENCE

Level III.

Complications in growth-friendly spinal surgeries for early-onset scoliosis: Literature review

BACKGROUND

The treatments for early-onset scoliosis (EOS), defined as curvature of the spine with onset before 10 years of age, continue to pose a great challenge for pediatric orthopedics. The treatment goals for EOS include minimizing spinal deformity while maximizing thoracic volume and pulmonary function. Different surgical techniques have different advantages and drawbacks; however, the two major concerns in the management of EOS are repeated surgeries and complications.

AIM

To review the current literature to assess the safety of EOS surgical treatment in terms of the rate of complications and unplanned surgeries.

METHODS

In January 2021 two independent reviewers systematically searched three electronic medical databases (PubMed, the Cochrane Library, and Embase) for relevant articles. Every step of the review was done according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Due to the heterogeneity of articles and topics after data analysis, a descriptive (synthetic) analysis was performed.

RESULTS

A total of 2136 articles were found. Forty articles were included in this systematic review, after applying our inclusion and exclusion criteria. EOS surgery has a varying but high rate of complications. The most frequent complications were categorized as implant (54%), general (17%), wound (15%) and alignment (12%). The rate of complications might have been even higher than reported, as some authors do not report all types of complications. About 54% of patients required unplanned surgeries due to complications, which comprised 15% of all surgeries.

CONCLUSION

The literature concerning the definitions, collection, and interpretation of data regarding EOS surgery complications is often difficult to interpret. This creates problems in the comparison, analysis, and improvement of spine surgery practice. Additionally, this observation indicates that data on the incidence of complications can be underestimated, and should be interpreted with caution. Awareness of the high rate of complications of EOS surgery is crucial, and an optimal strategy for prevention should become a priority.

Removal of instrumentation for postoperative spine infection: systematic review

OBJECTIVE

Currently, no consensus exists as to whether patients who develop infection of the surgical site after undergoing instrumented fusion should have their implants removed at the time of wound debridement. Instrumentation removal may eliminate a potential infection nidus, but removal may also destabilize the patient's spine. The authors sought to summarize the existing evidence by systematically reviewing published studies that compare outcomes between patients undergoing wound washout and instrumentation removal with outcomes of patients undergoing wound washout alone. The primary objectives were to determine 1) whether instrumentation removal from an infected wound facilitates infection clearance and lowers morbidity, and 2) whether the chronicity of the underlying infection affects the decision to remove instrumentation.

METHODS

PRISMA guidelines were used to review the PubMed/MEDLINE, Embase, Cochrane Library, Scopus, Web of Science, and ClinicalTrials.gov databases to identify studies that compared patients with implants removed and patients with implants retained. Outcomes of interest included mortality, rate of repeat wound washout, and loss of correction.

RESULTS

Fifteen articles were included. Of 878 patients examined in these studies, 292 (33%) had instrumentation removed. Patient populations were highly heterogeneous, and outcome data were limited. Available data suggested that rates of reoperation, pseudarthrosis, and death were higher in patients who underwent instrumentation removal at the time of initial washout. Three studies recommended that instrumentation be uniformly removed at the time of wound washout. Five studies favored retaining the original instrumentation. Six studies favored retention in early infections but removal in late infections.

CONCLUSIONS

The data on this topic remain heterogeneous and low in quality. Retention may be preferred in the setting of early infection, when the risk of underlying spine instability is still high and the risk of mature biofilm formation on the implants is low. However, late infections likely favor instrumentation removal. Higher-quality evidence from large, multicenter, prospective studies is needed to reach generalizable conclusions capable of guiding clinical practice.

Efficacy of distal pedicle screw fixation as a caudal foundation in VEPTR growing rod constructs for early onset scoliosis

PURPOSE

Surgical treatment of Early Onset Scoliosis (EOS) is challenging. Stable and robust foundations are vital. We have assessed a small cohort of patients with a rib-based proximal fixation and a pedicle screw-based distal foundation for a distraction based growing rod system.

METHOD

This is a single center study in a tertiary spinal deformity unit with a catchment population of over 6 million. We performed a retrospective radiographic evaluation of 15 patients with EOS treated with Vertical Expandable Titanium Prosthetic Rib (VEPTR) implant between 2007 and 2017. The review of medical records and imaging data was performed to identify growth of the spine and complications with pedicle screws.

RESULTS

There were ten male and five female patients with an average age at index surgery of 4yrs 11 months. Mean length of follow-up was 6 yrs 9 months. Serial radiographs revealed improvements in mean Cobb angle of 12 degrees, T1-T12 height of 29 mm and T1-S1 height of 48 mm with no deterioration in distal LIV tilt angle. We report that none of these patients had any complications related to their pedicle screws including cut-out.

CONCLUSION

We report a technique which is efficacious and provides a mechanically robust distal fixation for VEPTR lengthening in early onset scoliosis.

Coronal imbalance after growing rod treatment in early-onset scoliosis: a minimum of 5 years' follow-up

OBJECTIVE

The objective of this study was to investigate the incidence and risk factors of coronal imbalance (CI) in patients with early-onset scoliosis (EOS) who underwent growing rod (GR) treatment.

METHODS

A consecutive series of 61 patients with EOS (25 boys and 36 girls, mean age 5.8 ± 1.7 years) who underwent GR treatment was retrospectively reviewed. Postoperative CI was defined as postoperative C7 translation on either side ≥ 20 mm. Patients were divided into an imbalanced and a balanced group. Coronal patterns were classified into three types: type A (C7 translation < 20 mm), type B (C7 translation ≥ 20 mm with C7 plumb line [C7PL] shifted to the concave side of the curve), and type C (C7 translation ≥ 20 mm and a C7PL shifted to the convex side of the curve).

RESULTS

Each patient had an average of 5.3 ± 1.0 lengthening procedures and was followed for an average of 6.2 ± 1.3 years. Eleven patients (18%) were diagnosed with CI at the latest distraction, 5 of whom graduated from GRs and underwent definitive fusion. However, these patients continued to present with CI at the last follow-up evaluation. The proportion of preoperative type C pattern (54.5% vs 16.0%, p = 0.018), immediate postoperative apical vertebral translation (30.4 ± 13.5 mm vs 21.2 ± 11.7 mm, p = 0.025), lowest instrumented vertebra tilt (11.4° ± 8.2° vs 7.3° ± 3.3°, p = 0.008), and spanned obliquity angle (SOA) (9.7° ± 10.5° vs 4.1° ± 4.5°, p = 0.006) values in the imbalanced group were significantly higher than in the balanced group. Multiple logistic regression demonstrated that a preoperative type C pattern and immediate postoperative SOA > 11° were independent risk factors for postoperative CI.

CONCLUSIONS

The incidence of CI in patients with EOS who underwent GR treatment was 18%. This complication could only be slightly improved after definitive spinal fusion because of the autofusion phenomenon. A preoperative type C pattern and immediate postoperative SOA > 11° were found to be the risk factors for CI occurrence at the latest follow-up.

[Nonfusion procedures in pediatric scoliosis]

The treatment of early onset scoliosis (EOS) in children is a complex and demanding challenge in the treatment of spinal deformities. Conservative treatment with physiotherapy is indicated in mild forms with a Cobb angle from 10° and additionally a corset treatment with a Cobb angle of more than 20°. After exhaustion of the conservative measures or a progression of spinal scoliosis of 10° or deformities of more than 35°, a surgical approach should be considered in order to prevent respiratory insufficiency as well as severe postural and thoracic deformities. In situations where growth is still ongoing fusion operations can lead to stunted growth, a crankshaft phenomenon or degeneration of alignment. Meaningful alternatives to a fusion are so-called growing rods as a distraction-based nonfusion technique, e.g. traditional growing rods (TGR) and magnetically controlled growing rods (MCGR) or as a further method a vertical expandable prosthetic titanium rib (VEPTR) device. The advantages and disadvantages of each operative procedure must be considered with respect to the risk profile of each patient and the experience of the surgeon in order to guarantee the best possible treatment.

Analysis of 280 Magnetically Controlled Growing Rod Lengthenings Comparing External Remote Control Readouts and Radiographic Measurements: Impact of Patient and Deformity Factors

BACKGROUND

This study aimed to assess the accuracy of the external remote control (ERC) digital readout to the radiographic measurement of magnetically controlled growing rod (MCGR) actuators undergoing lengthenings/expansions and to analyze the impact of patient and spinal deformity factors on the accuracy of the ERC digital readout.

METHODS

Single-surgeon database at 2 tertiary-care pediatric hospitals identified early-onset scoliosis patients with MCGR constructs. There were 14 males and 16 females with a minimum of 2 lengthenings included in the analysis. ERC readouts at each lengthening were recorded.

RESULTS

Sixty-six MCGR actuators were assessed in 30 patients which underwent 280 lengthenings (mean of 5.7 lengthenings). At individual lengthening sessions the ERC and radiographic measurements were correlated (r = 0.69, P<0.001). The summed radiographic measurements averaged 15% less than the summed ERC readouts (SD = 19%). The difference between the sum of radiographic measurements and ERCs was positively correlated with subsequent lengthenings (r = 0.94, P = 0.015). The accuracy of the ERC did not improve with increased grouped sessions (r = -0.54, P = 0.388) with no difference between the group with 2 and the group with ≥5 lengthenings (P = 0.670). In patients with dual rods, the difference was correlated between rods (r = 0.66, P<0.001) and the distraction of each rod was not significantly different from the other (P = 0.124). Patient weight correlated with the difference between the radiographs and ERC readouts (r = 0.27, P = 0.032). In patients with multiple grouped lengthenings, increased weight was positively correlated with an increase in measurement difference (mean r = 0.972).

CONCLUSIONS

Summed radiographic measurements during lengthening sessions averaged 15% less than the summed ERC readouts. The accuracy of radiographic measurements did not increase when sessions were grouped together (2 vs. ≥5). There was no difference in the ERC accuracy over lengthening sessions early versus late. Patient weight, but not body mass index, was positively correlated with the discrepancy between the ERC and radiographic measures.

LEVEL OF EVIDENCE

Level III.

Shilla Growth Guidance Compared With Magnetically Controlled Growing Rods in the Treatment of Neuromuscular and Syndromic Early-onset Scoliosis

STUDY DESIGN

Retrospective review of consecutive series of patients treated at two institutions.

OBJECTIVE

The aim of this study was to compare the health-related quality of life (HRQoL) and surgical outcomes of Shilla growth guidance and magnetically controlled growing rod (MCGR) treatment in patients with syndromic and neuromuscular early-onset scoliosis (EOS).

SUMMARY OF BACKGROUND DATA

Knowledge of the outcomes of Shilla instrumentation is limited.

METHODS

We identified 13 children treated with Shilla and 18 children treated with MCGR with syndromic or neuromuscular EOS (major curve ≥45 degree) before the age of 10 years with minimum 2-year follow-up. Outcome parameters included clinical data, radiographic as well as HRQoL outcomes (EOSQ-24 questionnaire).

RESULTS

Mean preoperative major curves were 64 degree (range, 45-108 degree) in the Shilla group and 58 degree (range, 45-85 degree) in the MCGR group (P = 0.151). At final follow-up, mean major curves were 31 degree (range, 9.4-54 degree ) and 30 degree (range, 16-53 degree), respectively (P = 0.392). The mean major curve correction was 45% in the Shilla group and 48% in the MCGR group during the follow-up (P = 0.383). Spinal (T1-S1) and T1-T12 growth were significantly better (P = 0.006 and 0.042) in the MCGR than in the Shilla group during the distraction period. At final follow-up, 11 (85%) children in the Shilla group and 17 (94%) in the MCGR group had achieved T1-T12 length of ≥18 cm (P = 0.202). There were significantly more surgical procedures in the MCGR group (mean 2.6 vs. 1.4, P = 0.034) with no difference in the number of complications (P = 0.768). EOSQ24 domains were similar at final follow-up.

CONCLUSION

Shilla growth guidance provided similar correction of spinal deformity, equal number of complications, but with significantly less surgical procedures in patients treated for EOS when compared with MCGR instrumentation. MCGR provided with slightly better spinal growth during the distraction period. There were no significant differences between the quality of life assessments.

LEVEL OF EVIDENCE

3.

Is rod diameter associated with the rate of rod fracture in patients treated with magnetically controlled growing rods?

INTRODUCTION

Few risk factors for fracture in magnetically controlled growing rods (MCGR) have been identified. We hypothesize an increased rate of rod fracture in small diameter rods compared to large diameter rods in patients with early-onset scoliosis (EOS). The purpose of this study was to determine the association between the diameter of MCGR constructs and the rate of rod fracture.

METHODS

Patients with EOS who underwent MCGR implantation-primary or conversion-from 2013 to 2018 were identified from two registries including 40 centers. Rod diameter sizes greater than 5.0 mm or less than or equal to 5.0 mm were defined as "Large" and "Small" rods, respectively. Only dual-rod constructs were included. The primary outcome measure collected was rod fracture at any point in treatment up to the most recent follow-up. Cox regression was utilized for unequal follow-up to compare rate of breakage at the last follow-up between cohorts.

RESULTS

527 patients with 1,054 rods were included. 552 (52.4%) rods had a diameter of less than or equal to 5.0 mm and 461 (43.7%) rods had a diameter of greater than 5.0 mm. 41 (3.9%) rods were missing a recorded rod diameter and were not included in the analysis to determine the association between the rate of fracture and rod diameter. 20 (1.9%) total rod fractures occurred: 9 (1.6%) rods with diameters of ≤ 5.0 mm, 10 (2.2%) rods with diameters of > 5.0 mm, and 1 uncategorized rod (p = 0.529). No difference in the rate of rod fracture or survival distribution was found between rod diameters of > 5.0 mm and ≤ 5.0 mm even after stratification by ambulatory status, major coronal curve, weight, or location of anchors.

DISCUSSION

Rod fracture appears to be a rare event in dual MCGR constructs and rod diameter does not seem to be associated with the incidence or rate of rod fracture. Surgeons may consider other criteria for selecting rod diameter in their patients such as patient size, amount of surgical correction, single vs. dual constructs, and risk of hardware prominence.

Magnetically controlled growing rods in the treatment of early onset scoliosis: a single centre experience of 44 patients with mean follow-up of 4.1 years

Aims

Magnetically controlled growing rods (MCGR) have been gaining popularity in the management of early-onset scoliosis (EOS) over the past decade. We present our experience with the first 44 MCGR consecutive cases treated at our institution.

Methods

This is a retrospective review of consecutive cases of MCGR performed in our institution between 2012 and 2018. This cohort consisted of 44 children (25 females and 19 males), with a mean age of 7.9 years (3.7 to 13.6). There were 41 primary cases and three revisions from other rod systems. The majority (38 children) had dual rods. The group represents a mixed aetiology including idiopathic (20), neuromuscular (13), syndromic (9), and congenital (2). The mean follow-up was 4.1 years, with a minimum of two years. Nine children graduated to definitive fusion. We evaluated radiological parameters of deformity correction (Cobb angle), and spinal growth (T1-T12 and T1-S1 heights), as well as complications during the course of treatment.

Results

The mean Cobb angles pre-operatively, postoperatively, and at last follow-up were 70° (53 to 103), 35° (15 to 71) and 39° (15 to 65) respectively (p < 0.001). Further, there was a mean of 14° (-6 to 27) of additional Cobb angle correction upon graduation from MCGR to definitive fusion. Both T1-T12 and T1-S1 showed significant increase in heights of 27 mm and 45 mm respectively at last follow-up (p < 0.001). Ten children (23%) developed 18 complications requiring 21 unplanned operations. Independent risk factors for developing a complication were single rod constructs and previous revision surgery.

Conclusion

MCGR has the benefit of avoiding multiple surgeries, and is an effective tool in treatment of early-onset scoliosis. It also maintains the flexibility of the spine, allowing further correction at the time of definitive fusion.

Cite this article: Bone Joint Open 2020;1-7:405–414.

Early-Onset Scoliosis Treated With Magnetically Controlled Growing Rods

The recently developed magnetically controlled growing rod (MCGR) system has gained popularity because it limits additional surgical lengthening procedures and promises reduction of the complication rate previously reported for the traditional growing rods. A retrospective single-center study was performed. Demographic and complications data were recorded. A statistical analysis was conducted to quantify the effect of MCGR placement and of subsequent lengthening on the Cobb angle, T1-T12 kyphosis, and the distances from T1-T12 and T1-S1. Twenty-four patients met the inclusion criteria. Six had idiopathic scoliosis and 18 patients had nonidiopathic scoliosis (neuromuscular and syndromic scoliosis). Nine patients underwent primary MCGR placement, and 15 had the traditional growing rods removed and replaced with MCGRs. The mean age at surgery and at last follow-up was 6.3 years and 8.8 years, respectively. The mean follow-up was 29.2 months. The MCGR placement significantly reduced the Cobb angle and kyphosis by an average of 21.33° and 10.79°, respectively. The T1-T12 and the T1-S1 distances increased an average of 1.19 and 1.89 cm/year, respectively, during the follow-up period. The average percentage of achieved-to-intended distraction was 65% on the concave side and 68% on the convex side at last follow-up. There were 9 postoperative complications in 8 (33%) patients, 6 of whom had nonidiopathic scoliosis. The MCGR system is reliable and effective in the treatment of patients affected by early-onset scoliosis. [Orthopedics. 2020;43(6):e601-e608.].

Is Growth-friendly Surgical Treatment Superior to One-stage Posterior Spinal Fusion in 9- to 11-year-old Children with Congenital Scoliosis?

BACKGROUND

The distraction-based growth-friendly technique has become a mainstay of treatment for young children with long-spanned congenital scoliosis. However, in patients who are 9 years to 11 years old, the choice is much less clear, and posterior spinal fusion is also a potential option.

QUESTIONS/PURPOSES

Comparing growth-friendly scoliosis surgery and posterior spinal fusion, which technique (1) provides greater correction of spinal deformity, (2) is associated with more surgical complications, and (3) results in greater improvement in pulmonary function tests, health-related quality of life scores, other patient-reported outcomes?

METHODS

Between 2009 and 2017, one spinal center performed 212 spinal interventions for scoliosis in patients aged between 9 years and 11 years old and who had open triradiate cartilage, including 40 patients with growth-friendly approaches (34 with growing-rod technique and six with a vertical expandable prosthetic titanium rib) and 172 with one-stage posterior spinal fusion, respectively. During this period, our general indications for using growth-friendly surgery were patients with open triradiate cartilage, major curve higher than 40°, and upper and lower end vertebrae involving at least eight segments. Twelve patients with a median (range) age of 9.3 years (9 to 11) treated with growth-friendly surgery met the following inclusion criteria: (1) had at least two lengthening procedures before definitive spinal fusion along with 2 years of follow-up after definitive spinal fusion; (2) had been followed until skeletal maturity (Risser grade ≥ 4); and (3) with complete radiographic and clinical data (health-related quality of life (HRQoL) and pulmonary function test results) preoperatively and at the latest follow-up. A group of patients between 9 years and 11 years old and underwent one-stage posterior spinal fusion was selected from our database of patients with congenital scoliosis. Our general indications for using one-stage posterior spinal fusion were patients with a major curve greater than 40°, and with thoracic height higher than 18 cm. Sixty-two patients who had open triradiate cartilage and had been followed until skeletal maturity (Risser grade ≥ 4) were accounted for. In this retrospective, controlled study, we matched patients in the posterior spinal fusion group to those 12 patients who had growth-friendly surgery by age, sex, pathologic findings, major curve size, and location of the apex of the major curve (2:1 matching provided 24 patients in the control group). The median (range) age was 9.8 years (9 to 11). We then compared the groups in terms of magnitude of correction and postoperative complications. Surgical complications, including infection, implant-related complications, and alignment-related complications were evaluated and classified using the surgical complications grading system. Pulmonary function tests and HRQoL were also compared between groups. Pulmonary function tests were performed at the same center with a spirometer. HRQoL were assessed by questionnaire, including the 24-item Early-onset Scoliosis questionnaire for parent-reported outcomes and the Scoliosis Research Society-22 questionnaire for patient-reported outcomes. All patients involved in this study gave their informed consent.

RESULTS

The posterior spinal fusion group achieved a greater correction magnitude at the latest follow-up (median [range] 46% [28 to 70] versus median 34% [9 to 58], difference of medians = 11%; p < 0.001) than the growth-friendly group. A higher proportion of patients in the growth-friendly group had complications than in the posterior spinal fusion group (7 of 12 versus 4 of 24; p = 0.03). There were no between-group differences in terms of pulmonary function tests. Few differences were found between the groups in terms of 24-item Early-onset Scoliosis parental impact (median [range] 60 [44 to 83] for the growth-friendly group versus median 71 [55 to 87] for the posterior spinal fusion group, difference of medians = 13; p = 0.001), financial burden (median 44 [30 to 55] for the growth-friendly group versus median 62 [53 to 75] for the posterior spinal fusion group, difference of medians = 16; p < 0.001) and the Scoliosis Research Society-22 self-image scores (median 3.8 [3.2 to 4.3] for the growth-friendly group versus median 4.4 [4.1 to 4.6] for the posterior spinal fusion group, difference of medians = 0.5; p = 0.006) at the latest follow-up, and those differences that were observed all favored the posterior spinal fusion group.

CONCLUSIONS

In light of the superior deformity correction and fewer observed complications with posterior spinal fusion, and the absence of important differences in validated outcomes scores or pulmonary function tests, posterior spinal fusion might be a better choice for 9- to 11-year-old children with long-spanned congenital scoliosis and limited growth potential in the intended instrumentation area.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Implant Retention or Removal for Management of Surgical Site Infection After Spinal Surgery

STUDY DESIGN

A literature review.

OBJECTIVE

To summarize the implant removal rate, common bacterial organisms found, time of onset, ratio of superficial to deep infection, and regurgitating the prevalence among all the retrospective and prospective studies on management and characterization of surgical site infections (SSIs).

METHODS

PubMed was searched for articles published between 2000 and 2018 on the management or characterization of SSIs after spinal surgery. Only prospective and retrospective studies were included.

RESULTS

A total of 49 articles were found relevant to the objective. These studies highlighted the importance of implant removal to avoid recurrence of SSI. The common organisms detected were methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermis, Staphylococcus epidermis, Staphylococcus aureus, and Propionibacterium acnes, with prevalence of 1% to 15%. A major proportion of all were deep SSI, with minority reporting on late-onset SSI.

CONCLUSION

Long-term antibiotics administration, and continuous irrigation and debridement were common suggestion among the authors; however, the key measure undertaken or implied by most authors to avoid risk of recurrence was removal or replacement of implants for late-onset SSI.

Unplanned return to operation room (OR) following growing spinal constructs (GSCs) in early onset scoliosis (EOS)-a multi-centric study

PURPOSE

To evaluate the incidence and risk factors associated with the unplanned return to OR in EOS.

METHODS

Medical records of 51 patients of EOS operated at three different centres using various types of GSCs were evaluated for complications requiring unplanned surgeries. Data were analysed to find out rate of unplanned surgeries in relation to the aetiology, age and Cobb angle at index surgery, type of implant, cause of unplanned surgery, and management required.

RESULTS

Out of 51 patients, three did not meet inclusion criteria. Forty-eight patients of EOS operated by GSCs with a mean age of 6.7 years (range 2-12 years) with an average follow-up of 67.3 months were studied. There were 30 congenital, 10 idiopathic, 4 syndromic, and 4 neuromuscular cases. Thirty-nine out of 48 patients had one or more unplanned surgeries on follow-up (81.25%). Out of total 248 surgeries following index procedure, 82 were unplanned surgeries (33.06%), including 53 implant revisions, 12 implant-removal, 14 debridement, and 2 flaps. The common complications were 24.14% rod/screw breakage, 42.53% anchor pull-out, 16.09% infections, 6.90% wound dehiscence, and 4.6% neuro deficits. Unplanned surgeries were significantly higher in syndromic (58.8%) and neuromuscular (52.9%) than congenital (27.2%) and idiopathic (37.8%) cases (p < 0.05). Age at index procedure < 5 years had higher unplanned surgeries than age > 5 years (2.5 and 1.23 per patient, respectively,  p < 0.05). Type of implant and initial Cobb angle did not significantly affect the rate of unplanned surgeries (p  > 0.05) CONCLUSION: GSCs in EOS require a frequent revisit to operation room which should be well understood by the surgeon and parents.

Usefulness of inflammatory markers and clinical manifestation for an earlier method to diagnosis surgical site infection after spinal surgery

PURPOSE

To put forward a method for earlier diagnosis of surgical site infection (SSI) after spinal surgery and identify the best cut-offs of the selective signs.

METHODS

Ninety cases were prospectively collected in consecutive patients who underwent spinal surgery. The patients were divided into the SSI group and the normal group. White blood cell (WBC) count, lymphocyte count, serum amyloid A (SAA), procalcitonin (PCT) and C-reactive protein (CRP) were collected pre-operatively and at three andsix days post-operatively. Erythrocyte sedimentation rates (ESR) were acquired pre-operatively and at six days post-operatively. Body temperature (BT) was measured every day during hospitalisation. The conditions of the surgical sites were recorded at three and six days post-operatively. Differences of BT, the conditions of the wound and the values of the inflammatory markers between the two groups were studied. Finally, we used the receiver operating characteristic curve (ROC curve) to determine the best cut-offs of the selected signs.

RESULTS

Of the 90 patients, SSI occurred in seven and five of them reached a definite diagnosis of SSI as their bacterial cultures were positive. Significant differences were found in CRP levels at three and six days post-operatively with a cut-off of > 59.4 mg/L and > 34.9 mg/L, respectively; ESR level at six days post-operatively with a cut-off of > 51.5 mm/h; PCT at three days post-operatively with a cut-off of > 0.11 ng/mL; and BT at three days post-operatively with a cut-off of > 37 °C. Also, examination of the wound is also an important sign of SSI.

CONCLUSION

CRP, ESR and PCT are considered useful markers for earlier diagnosis of SSI. Combining the above markers with BT and the wound condition yields more accurate results.

Idiopathic Early-onset Scoliosis: Growing Rods Versus Vertically Expandable Prosthetic Titanium Ribs at 5-year Follow-up

BACKGROUND

Distraction-based techniques allow spinal growth until skeletal maturity while preventing curve progression.

METHODS

Two multicenter early-onset scoliosis databases were used to identify patients with idiopathic spine abnormalities treated with traditional growing rods (TGR) or vertically expandable titanium ribs (VEPTR). Patients underwent at least 4 lengthenings and had at least 5-year follow-up. Significance was set at P<0.05.

RESULTS

In total, 50 patients treated with TGR and 22 treated with VEPTR were included. Mean (±SD) age at surgery was 5.5 (±2.0) years for the TGR group versus 4.3 (±1.9) years for the VEPTR group (P=0.044); other demographic parameters were similar. VEPTR patients had more procedures (mean 15±4.2) than TGR patients (mean 10±4.0) (P=0.001). Unilateral constructs were present in 18% (4 of 22) of VEPTR and 16% (8 of 50) of TGR patients. Bilateral constructs spanned a mean 2.1 additional surgical levels and exposed patients to 1.6 fewer procedures than unilateral constructs. Curve correction was similar between bilateral and unilateral constructs. TGR patients experienced greater curve correction (50%) than VEPTR patients (27%) (P<0.001) and achieved a greater percentage of thoracic height gain (24%) than VEPTR patients (12%) (P=0.024). At latest follow-up, TGR patients had better maintenance of curve correction, less kyphosis, and 15% greater absolute gain in thoracic height versus VEPTR patients. TGR patients had a lower rate of wound complications (14%) than VEPTR patients (41%) (P=0.011).

CONCLUSIONS

In patients with idiopathic early-onset scoliosis, TGRs produced greater initial curve correction, greater thoracic height gains, less kyphosis, and lower incidence of wound complications compared with VEPTR.

LEVEL OF EVIDENCE

Level III.

Standard and magnetically controlled growing rods for the treatment of early onset scoliosis

Distraction based spinal instrumentation represents the most common and standard surgical technique to correct early onset scoliosis (EOS), i.e., scoliosis which has been diagnosed before the age of 10 years. Surgical treatment of EOS aims at controlling spinal deformity while maintaining spinal growth which is mandatory for the development of normal lung capacity. To achieve these goals the spinal instrumentation needs to be distracted to facilitate spinal growth during treatment. Distraction can be obtained by repeated surgical lengthenings (traditional growing rods, TGRs) or using magnetically controlled growing rods (MCGRs), which can be lengthened using external remote controller on an outpatient basis. The outcomes of TGR instrumentation for EOS are well described with follow-up until skeletal maturity: normal spinal growth can be maintained, 40-50% of the scoliosis can be corrected, but there is an over 50% risk of complications including deep wound infection, rod failure, and instrumentation pull-out. MCGR instrumentation may reduce the risk of wound related complications, provides similar deformity correction, but may not provide as much spinal growth. Metallosis around the instrumentation necessitates MCGR removal and definitive final instrumented fusion at the end of growth friendly management. Even severe EOS can be treated using distraction based spinal instrumentation.

Comprehensive Wound Risk Stratification of Rib-Based Distraction Instrumentation Procedures

STUDY DESIGN

Single-center retrospective analysis of a prospectively collected registry.

OBJECTIVES

Identify factors predictive of rib-based distraction (RBD) instrumentation wound complication. Create a risk stratification model for RBD instrumentation wound complication.

SUMMARY OF BACKGROUND DATA

RBD instrumentation procedures have a high rate of wound complications, often requiring unplanned operative treatment. Currently, there is a relative lack of understanding of RBD complication risk factors compared with the comprehensive understanding of complication risk factors for other spine surgeries.

METHODS

Between January 2011 and September 2015, patients treated with RBD instrumentation at a single institution were analyzed for risk factors associated with surgical wound complications that resulted in unplanned operative treatment. Univariate logistic regression determined predictors of wound complication and multivariate regression determined independent predictive factors; α = 0.10.

RESULTS

A total of 122 patients aged 0-18 years underwent 140 implant surgeries in which 22 resulted in complications: 18 (82%) infectious and 4 (18%) noninfectious. Mean age at surgery was 5.2 years. Univariate analysis showed a correlation between wound complication rates and the following: male gender (p = .097), diapered patient with lower back incision (p = .004), bilateral procedure (p = .008), more than three incisions (p = .011), left iliac incision (p = .097), right iliac incision (p = .009), patient age ≤4 years (p = .10), and operative time >150 minutes (p = .079). Multivariate analysis identified the following independent predictors: age ≤ 4 years (p = .002), male gender (p = .04), number of skin incisions (p = .001), left iliac incision (p = .018), and nutritionally challenged (p = .044). The multivariate model predicted wound complications with an area under the receiver operating characteristic curve of 0.88.

CONCLUSIONS

Knowledge of risk factors for RBD instrumentation wound complications can be used to construct patient risk models. This can identify patients at higher risk for complications and influence clinical decision making.

LEVEL OF EVIDENCE

Level II.

Nasal Swab Screening for Staphylococcus aureus in Spinal Deformity Patients Treated With Growing Rods

BACKGROUND

Surgical-site infections are one of the most concerning complications in patients treated with growing rods (GR). The purpose of this study was to evaluate the use of preoperative screening for Staphylococcus aureus (SA) for all growing spine procedures, and if this would permit alteration of prophylactic antibiotics to cover the identified resistances.

METHODS

All patients were identified who had SA screening during the course of GR treatment. In otal, 34 patients [23 neuromuscular (NMS), 4 congenital, 4 idiopathic scoliosis (IS), and 3 syndromic] were identified who had 111 preoperative screenings [79 lengthenings, 23 insertions, 6 revisions, and 3 conversions to posterior spinal fusions (PSF)]. Mean age at GR insertion was 5.5 years (2 to 11 y).

RESULTS

There were 11 methicillin-resistant Staphylococcus aureus (MRSA) "+" screenings in 6 patients (5 NMS, 1 IS): 3 in 3 patients before GR insertion and 8 in 3 patients (all 3 were negative at GR insertion screening) at subsequent surgeries. There were 23 methicillin-sensitive Staphylococcus aureus (MSSA) "+" screenings in 12 patients (7 NMS, 2 congenital, 2 IS, 1 syndromic): 2 in 2 patients before GR insertion and 21 in 10 patients at subsequent surgeries (18 lengthenings, 3 revisions). Overall, 13 patients (3 MRSA+10 MSSA) were initially negative but screened positive for the first time at a subsequent surgery (12 lengthenings, 1 GR to PSF). All patients (n=5) with positive screenings before GR insertion were in patients with NMS (3 MRSA, 2 MSSA). On the basis of sensitivities, 9 patients demonstrated SA resistance to cefazolin (8 MRSA and 1 MSSA) and 6 to clindamycin (5 MRSA and 1 MSSA). Hence, if cefazolin was routinely used for all patients 26.5% of patients (9/34) would have been inadequately covered at some point during their GR treatment; clindamycin, 17.7% (6/34).

CONCLUSION

The use of SA nasal swab screening in GR patients identified 9 patients (26.5%) whose prophylactic antibiotics (cefazolin) could be altered to permit appropriate SA coverage.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

Best Practice Guidelines for Surgical Site Infection Prevention With Surgical Treatment of Early Onset Scoliosis

BACKGROUND

Postoperative surgical site infection (SSI) is unfortunately a commonly encountered complication in the surgical treatment of children with Early Onset Scoliosis (EOS). There is documented variation in the treatment of this patient population. Previous work building consensus for the approach to high risk patients (eg, neuromuscular etiology) has been promising. The goal of the current study is to apply similar principles to develop consensus-based guidelines for the treatment of patients with EOS.

METHODS

A focus group from 2 multicenter pediatric spine deformity study groups developed a list of statements to be distributed to a larger group of EOS experts. Using the Delphi process, participants were presented with a systematic review of the literature as well as a review of current practices in growth friendly surgery. The first round was conducted using an electronic survey. Results of this survey were then discussed face-to-face and the statements were further refined. A final round was conducted using the Audience Response System, allowing participants to vote for each statement (strongly agree or agree). Agreement >80% or disagreement <20% was considered consensus.

RESULTS

A total of 29 of 57 statements reached consensus. Negative statements (statements of disagreement) were excluded, so the final consensus guidelines included 22 statements. The number of statements from the previously published Best Practice Guidelines (BPG) approved for insertion and lengthening growth friendly procedures were 12 of 14 and 11 of 14, respectively. The high risk BPG therefore does not cover all of the issues specific to the EOS population, and explains why 22 statements reached consensus in the current guideline. Upon completion of the surveys, 100% of the participants agreed to support its publication.

CONCLUSIONS

Using the Delphi process several "best practices" were developed for growth friendly surgical treatment of EOS.

LEVEL OF EVIDENCE

Level V.

Comparison of the Effects of Magnetically Controlled Growing Rod and Tradiotinal Growing Rod Techniques on the Sagittal Plane in the Treatment of Early-Onset Scoliosis

Objective

Comparing the effects of magnetically controlled growing rod (MCGR) and traditional growing rod (TGR) techniques on the sagittal plane in the treatment of early-onset scoliosis (EOS).

Methods

Twelve patients were operated using dual MCGR technique in one center, while 15 patients were operated using dual TGR technique for EOS in another center. Patients’ demographic characteristics, complications and radiological measurements such as cobb angle, thoracic kyphosis, lumbar lordosis, T1–S1 range (mm), proximal junctional angle, distal junctional angle, sagittal balance, coronal balance, pelvic incidence, sacral slope and pelvic tilt were assessed and compared in preoperative, postoperative and last follow-up period.

Results

Age and sex distributions were similar in both groups. The mean number of lengthening in the MCGR group was 12 (8–15) and 4.8 (3–7) in the TGR group. Two techniques were shown to be effective in controlling the curvature and in the increase of T1–S1 distance. In TGR group, four patients had rod fractures, six patients had screw pull-out and four patients had an infection, whereas three patients had screw pull-out and one patient had infection complications in the MCGR group.

Conclusion

There was no significant difference between the two groups in terms of cobb angle, coronal and sagittal balance and sagittal pelvic parameters. MCGR can cause hypokyphosis and proximal junctional kyphosis in a minimum 2-year follow-up period. The implant-related complications were less in the MCGR group. However, larger case groups and longer follow-up periods are required for the better understanding of the superiority of one method on other in terms of complications.

A Multicenter Study of the Epidemiology of Deep Surgical Site Infections in Children With Nonidiopathic Early-Onset Scoliosis Including Associated Pathogens

STUDY DESIGN

Retrospective descriptive.

OBJECTIVES

Identify incidence and risk of deep surgical site infections (SSIs), associated pathogens, and antibiotic susceptibility in patients with nonidiopathic early-onset scoliosis (EOS) undergoing growth-friendly (GF) spine surgery.

BACKGROUND

SSIs following GF procedures for EOS are well described, but epidemiologic trends in associated pathogens have not been well characterized.

METHODS

The Children's Spine Study Group database was queried for children ≤18 years of age undergoing GF procedures for nonidiopathic EOS at 11 institutions from September 2001 to January 2016. Deep SSIs reported within 90 days of procedures were reviewed for associated pathogens and their susceptibility profiles. Data were analyzed to calculate incidence and risk.

RESULTS

593 patients (median age 5.7 years, IQR 3.3-8.0 years) with scoliosis due to congenital (45%), neuromuscular (39%), and syndromic (16%) disorders underwent 5,072 procedures. The incidence of deep SSIs per patient was 12.6%; 75 patients had one or more deep SSIs. The risk of deep SSIs per procedure was 1.95% as 99 SSIs occurred after the 5072 procedures. Overall, 48% of deep SSIs followed expansion procedures. Pathogen(s) were cultured from 92% of SSIs including gram-positive cocci (GPC, 90.1%) and/or gram-negative rods (GNR, 17.6%). Methicillin-susceptible Staphylococcus aureus (48.4% of SSIs), methicillin-resistant S. aureus (23.1%), and coagulase negative staphylococci (CoNS, 8.8%) were the most common GPCs. Escherichia coli (5.5% of SSIs), Enterobacter cloacae (4.4%), and Pseudomonas aeruginosa (4.4%) were the most common among GNRs. GNR susceptibility to cefazolin was 41% during the study period, whereas GPC susceptibility to cefazolin was 59%.

CONCLUSION

The risk of SSIs can potentially be reduced for this vulnerable population by routinely reviewing the local epidemiology of SSIs, including the associated pathogens and their susceptibility patterns. As GNR susceptibility to cefazolin was only 41%, expanding prophylaxis to include aminoglycosides for GNR is prudent.

LEVEL OF EVIDENCE

Level IV.

Risk Factors for Early Infection in Pediatric Spinal Deformity Surgery: A Multivariate Analysis

STUDY DESIGN

Retrospective case-control study.

OBJECTIVES

To identify risk factors for early deep surgical site infections (SSIs; within three months of index procedure) following pediatric spinal deformity surgery.

BACKGROUND

Deep surgical site infections (SSIs) following pediatric spinal deformity surgery are a source of significant morbidity. We sought to identify independent risk factors for early infection following primary, definitive single-stage pediatric posterior spinal fusion and instrumentation (PSFI).

METHODS

A total of 616 consecutive patients (2001-2016) from an institutional prospectively maintained Pediatric Orthopaedic Spine database were identified that met inclusion criteria of definitive single-stage PSFI. Early deep SSI was defined as infection within three months of index procedure requiring surgical intervention. A multivariate analysis of demographics, comorbidities, and perioperative factors was performed and independent risk factors were identified.

RESULTS

Eleven patients (1.6%) developed an early deep SSI. Independent risk factors for SSI identified were nonidiopathic (neuromuscular, syndromic, and congenital) etiologies of scoliosis (adjusted odds ratio [aOR]: 8.384, 95% confidence interval [CI]: 1.784-39.386, p = .007) and amount of intraoperative crystalloids (aOR: 1.547 per additional liter of fluid, 95% CI: 1.057-2.263, p = .025). Mean crystalloid administered in the SSI group was 3.3 ± 1.2 L versus 2.4 ± 1.0 L in the noninfected group (p = .019). On univariate analysis, there was no significant difference in weight of patients between cohorts (p = .869) or surgery time (p = .089). There was also no significant difference in infection rates from redosing of antibiotics intraoperatively after 3 hours of surgery (p = .231).

CONCLUSIONS

Nonidiopathic scoliosis and amount of intraoperative crystalloids were independently associated with early postoperative SSI. Further investigation into intraoperative fluid management may identify modifiable risk factors for early postoperative SSI in primary pediatric spinal deformity posterior spinal fusion patients.

LEVEL OF EVIDENCE

Level III, case-control study.

Treatment of early onset spinal deformities with magnetically controlled growing rods: a single centre experience of 30 cases

PURPOSE

The treatment of early onset scoliosis continues to be a major challenge, even when using motorized growth-sparing implants. We report on 30 cases operated on with magnetically controlled growing rods (MCGRs) at our institution, analyzing radiological parameters and complications, comparing our results with the literature and presenting a special implant fixation technique. A separate focus highlights the challenges of conversion from previous non-motorized implants.

METHODS

Consecutive case series. The nature and effects of complications were recorded for all patients. Radiographic evaluations were performed for patients with a minimum follow-up of two years. Separate analyses were carried out for patients who were previously treated with non-motorized growth-sparing implants.

RESULTS

There were 12 documented complications in 11/30 (37%) patients leading to 13 unplanned returns to the operating room. In all, 18/30 patients had a minimum follow-up of two years. Major curve and main kyphosis, as well as T1 to T12 and T1 to S1 distances significantly improved with MCGR implantation, however, less in patients converted from previous growth-sparing surgical treatment. While the achieved correction of the major curve was maintained, there was a loss of kyphosis correction with subsequent implant lengthening. Gain in implant length decreased with increasing number of extensions.

CONCLUSION

Despite improved patient's comfort, MCGR show a considerable complication rate. Coronal plane deformities can be well controlled, but diminished implant lengthening is already apparent within two years after MCGR implantation. Central databases should help to clarify unresolved aspects and optimize the treatment of these young patients.

LEVEL OF EVIDENCE

IV.

Early Onset Scoliosis: Is there an Improvement in Quality of Life With Conversion From Traditional Growing Rods to Magnetically Controlled Growing Rods?

BACKGROUND

Modern treatment of early onset scoliosis (EOS) includes implantation of traditional growing rods (TGR) or magnetically controlled growing rods (MCGR) for posterior-based distraction if nonoperative treatment plans failed. The recent MCGR innovation has largely been expected to improve patient and family burden by avoiding frequent return to the operating room. At least one study has shown no HRQoL difference between TGR and MCGR, but none have specifically investigated a cohort of conversion patients whose families have experienced both.

METHODS

An EOS database was queried for all patients treated with TGR, MCGR, and those converted from TGR to MCGR who had at least 1 pretreatment and 1 posttreatment HRQoL assessment (EOSQ-24). Data on demographics, diagnoses, and major curve size, as well as EOSQ-24 domain scores were studied.

RESULTS

There were 156 TGR, 114 MCGR, and 32 conversion patients, with an average of 2.0 years between first and final EOSQ-24 surveys. There was no significant difference in outcome in any EOSQ-24 domain between the converts and the other 2 treatment groups. There was a significant post-op improvement in MCGR versus TGR in transfers and energy level (P=0.01; P=0.01).

CONCLUSIONS

Although patient families and their surgeons may subjectively report improved HRQoL after conversion from TGR lengthenings to in-office MCGR lengthenings, these improvements were seen in transfer and fatigue domains, not burden or satisfaction. Although the EOSQ-24 is a well-validated EOS metric, it may not be sensitive enough to overcome the QoL floor-effect associated with the diagnosis itself, or perhaps the improvement in QoL must be assessed over a longer interval to assess meaningful change.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

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.