Deep wound infections after spinal fusion in children with cerebral palsy: a prospective cohort study

What is the role of plastic surgery for incisional closures in pediatric spine surgery? Results from a pediatric spine study group survey

Current best practice guidelines recommend a plastics-style multilayer wound closure for high-risk pediatric spine surgery. However, plastic surgery closure of spinal incisions remains controversial. This study investigates surgeon perceptions and practice patterns regarding plastic surgery multilayered closure (PMC) in pediatric spine surgery. All surgeons in an international pediatric spine study group received a 30-question survey assessing incisional closure practices, frequency of plastic surgery collaboration, and drain management. Relationship to practice size, setting, geographic region, and individual diagnoses were analyzed. 87/178 (49%) surgeons responded from 79% of participating sites. Plastics utilization rates differed by diagnosis: neuromuscular scoliosis 16.9%, early onset scoliosis 7.8%, adolescent idiopathic scoliosis 2.8% (P < 0.0001). Plastics were used more for early onset scoliosis [odds ratio (OR) 18.5, 95% confidence interval (CI): 8.5, 40.2; P < 0.001] and neuromuscular scoliosis [OR 29.2 (12.2, 69.9); P < 0.001] than adolescent idiopathic scoliosis. Plastics use was unrelated to practice size, setting, or geographic region (P ≥ 0.09). Respondents used plastics more often for spina bifida and underweight patients compared to all other indications (P < 0.001). Compared to orthopaedic management, drains were utilized more often by plastic surgery (85 vs. 21%, P = 0.06) and for longer durations (P = 0.001). Eighty-nine percent of surgeons felt plastics increased operative time (58 ± 37 min), and 34% felt it increased length of hospitalization. Surgeons who routinely utilize plastics were more likely to believe PMC decreases wound complications (P = 0.007). The perceived benefit of plastic surgery varies, highlighting equipoise among pediatric spine surgeons. An evidence-based guideline is needed to optimize utilization of plastics in pediatric spine surgery.

Modified frailty index independently predicts morbidity in patients undergoing 3-column osteotomy

PURPOSE

Adult Spinal Deformity (ASD) includes a spectrum of spinal conditions that can be associated with significant pain and loss of function. While 3-column osteotomies have been the procedures of choice for ASD patients, there is also a substantial risk for complications. The prognostic value of the modified 5-item frailty index (mFI-5) for these procedures has not yet been studied. The goal of this study is to evaluate the association of mFI-5 with 30-day morbidity, readmission, and reoperation following a 3-column osteotomy.

METHODS

The National Surgical Quality Improvement Program (NSQIP) database was queried to identify patients undergoing 3-Column Osteotomy procedures from 2011-2019. Multivariate modeling was utilized to assess mFI-5 and other demographic, comorbidity, laboratory, and perioperative variables as independent predictors of morbidity, readmission, and reoperation.

RESULTS

N = 971. Multivariate analysis revealed that mFI-5 = 1 (OR = 1.62, p = 0.015) and mFI-5 ≥ 2 (OR = 2.17, p = 0.004) were significant independent predictors of morbidity. mFI-5 ≥ 2 was a significant independent predictor of readmission (OR = 2.16, p = 0.022) while mFI-5 = 1 was not a significant predictor of readmission (p = 0.053). Frailty did not predict reoperation.

CONCLUSION

Frailty as defined by mFI-5 strongly and independently predicted increased odds of postoperative morbidity for patients undergoing 3-column osteotomy as surgical intervention for ASD. Only mFI-5 ≥ 2 was a significant independent predictor of readmission, while frailty did not predict reoperation. Other variables independently predicted increased and decreased odds of postoperative morbidity, readmission, and reoperation.

LEVEL OF EVIDENCE

III.

Does Routine Subspecialty Consultation Before High-Risk Pediatric Spine Surgery Decrease the Incidence of Complications?

BACKGROUND

Children with neuromuscular disorders and syndromic scoliosis who require operative treatment for scoliosis are at increased risk for postoperative complications. Complications may include surgical site infection and pulmonary system problems including respiratory failure, gastrointestinal system disorders, and others. The purpose of our study was to determine the effect of a standardized perioperative pathway specifically designed for management of high-risk pediatric patients undergoing surgery for scoliosis.

METHODS

The High-Risk Protocol (HRP) at our institution is a multidisciplinary process with subspecialty consultations before scoliosis surgery. This was a retrospective chart and radiographic review at a single institution. Inclusion criteria were high-risk subjects, age 8 to 18 years old, who underwent surgery between January, 2009 and April, 2009 with a minimum 2-year follow-up. Diagnoses included neuromuscular scoliosis or Syndromic scoliosis.

RESULTS

Seventy one subjects were analyzed. The mean age was 13 (±2 SD) years. Follow-up was 63 (±24 SD) months. The study group consisted of 35 subjects who had fully completed the HRP and the control group consisted of 36 subjects who did not. Nine of the 35 (26%) subjects in the HRP had surgery delayed while interventions were performed. Compared with controls, the study group had larger preoperative and postoperative curve magnitudes: 90 versus 73 degrees ( P =0.002) and 35 versus 22 degrees ( P =0.001). Pulmonary disease was more common in the HRP, 60 versus 31% ( P =0.013). The overall incidence of complications in the study group was 29% (10 of 35 subjects) and for controls 28% (10 of 36). There were no differences between groups for types of complications or Clavien-Dindo grades. Three subjects in the study group and 1 in the controls developed surgical site infection. Eleven subjects required unplanned reoperations during the study period.

CONCLUSIONS

The findings of our study suggest a structured pathway requiring routine evaluations by pediatric subspecialists may not reduce complications for all high-risk pediatric spine patients. Selective use of consultants may be more appropriate.

LEVEL OF EVIDENCE

Level III, Retrospective Cohort study.

Hospital Burdens of Patients With Cerebral Palsy Undergoing Posterior Spinal Fusion for Scoliosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Many patients undergoing posterior spinal fusion (PSF) for scoliosis have concurrent cerebral palsy (CP), which is associated with many medical comorbidities and inherent operative risk. We aimed to quantify the contribution of CP to increased cost, length of stay (LOS), and complication rates in patients with scoliosis undergoing PSF.

METHODS

Using the National Inpatient Sample database, we collected data regarding patient demographics, hospital characteristics, comorbidities, in-hospital complications, and mortality. Primary outcomes included complications, hospital LOS, and total hospital costs. Multivariate regression models assessed the contribution of CP to in-hospital complications, discharge status, and mortality. Linear regression identified the contribution of a diagnosis of CP on hospital LOS and inflation-adjusted cost.

RESULTS

Cerebral palsy was an independent predictor of several complications. The most striking differences were seen for mortality (odds ratio [OR]: 3.40, P < .001), a postoperative requirement for total parenteral nutrition (OR: 3.16, P < .001), urinary tract infection (OR: 2.75, P < .001), surgical site infection (OR: 2.67, P < .001), and pneumonia (2.21, P < .001). Patients with CP ultimately cost an additional $13 482 (P < .001) with a 2.07-day greater LOS (P < .001) than patients without CP.

CONCLUSION

Most complications were seen in higher rates in the CP cohort, with higher cost and LOS in patients with CP versus those with idiopathic scoliosis (IS). Our findings represent important areas of emphasis during preoperative consultations with patients with CP and their families. Extra care in patient selection and multifaceted treatment protocols should continue to be implemented with further investigation on how to mitigate common complications.

Risk factors for gastrointestinal complications after spinal fusion in children with cerebral palsy

DESIGN

Prospective cerebral palsy (CP) registry review.

OBJECTIVES

(1) Evaluate the incidence/risk factors of gastrointestinal (GI) complications in CP patients after spinal fusion (SF); and (2) investigate the validity of the modified Clavien-Dindo-Sink classification.

BACKGROUND

Perioperative GI complications result in increased length of stay (LOS) and patient morbidity/mortality. However, none have analyzed the outcomes of GI complications using an objective classification system.

METHODS

A prospective/multicenter CP database identified 425 children (mean, 14.4 ± 2.9 years; range, 7.9-21 years) who underwent SF. GI complications were categorized using the modified Clavien-Dindo-Sink classification. Grades I-II were minor complications and grades III-V major. Patients with and without GI complications were compared.

RESULTS

87 GI complications developed in 69 patients (16.2%): 39 minor (57%) and 30 major (43%). Most common were pancreatitis (n = 45) and ileus (n = 22). Patients with preoperative G-tubes had 2.2 × odds of developing a GI complication compared to oral-only feeders (OR 2.2; 95% CI 0.98-4.78; p = 0.006). Similarly, combined G-tube/oral feeders had 6.7 × odds compared to oral-only (OR 6.7; 95% CI 3.10-14.66; p < 0.001). The likelihood of developing a GI complication was 3.4 × with normalized estimated blood loss (nEBL) ≥ 3 ml/kg/level fused (OR 3.41; 95% CI 1.95-5.95; p < 0.001). Patients with GI complications had more fundoplications (29% vs. 17%; p = 0.03) and longer G-tube fasting periods (3 days vs. 2 days; p < 0.001), oral fasting periods (5 days vs. 2 days; p < 0.001), ICU admissions (6 days vs. 3 days; p = 0.002), and LOS (15 days vs. 8 days; p < 0.001). LOS correlated with the Clavien-Dino-Sink classification.

CONCLUSION

Gastrointestinal complications such as pancreatitis and ileus are not uncommon after SF in children with CP. This is the first study to investigate the validity of the modified Clavien-Dindo-Sink classification in GI complications after SF. Our results suggest a correlation between complication severity grade and LOS. The complexity of perioperative enteral nutritional supplementation requires prospective studies dedicated to enteral feeding protocols.

LEVEL OF EVIDENCE

Therapeutic-level III.

Antibiotic prophylaxis in high-risk pediatric spine surgery: Is cefazolin enough?

STUDY DESIGN

Retrospective study.

OBJECTIVE

To describe pathogens found in SSI during pediatric-instrumented spine surgery, and to assess the relationship between pathogens and the etiology of the spinal deformity. Surgical site infection (SSI) after pediatric spine fusion is a well-known complication with incidence rates between 0.5 and 42%, associated with the patient underlying disorder. Pathogens involved in SSI seem to be related to patient characteristics, such as the etiology of the spinal deformity. GNB (gram-negative bacilli) are more frequent in neuropathic, muscular, and syndromic conditions. High-risk pediatric patients with a spine deformity undergoing instrumented surgery might benefit from receiving perioperative intravenous prophylaxis for GNB.

METHODS

We conducted a retrospective study at our tertiary-care pediatric hospital from January 2010 to January 2017. We reviewed records of all episodes of SSI that occurred in the first 12 months postoperatively. All patients who underwent instrumented spine surgery were included in this study.

RESULTS

We assessed 1410 pediatric-instrumented spine surgeries; we identified 68 patients with deep SSIs, overall rate of 4.8%. Mean age at instrumented spine surgery was 12 years and 9 months. Time elapsed between instrumented surgery and debridement surgery was 28.8 days. Cultures were positive in 48 and negative in 20. Of the 48 positive culture results, 41 (72%) were GNB, 12 (21%) gram-positive cocci (GPC), three (5%) gram-positive anaerobic cocci (GPAC), and one (2%) coagulase-negative staphylococci (CoNS). Of the 68 patients with primary SSIs, 46 were considered to have a high risk of infection, which reported GNB in 81%, GPC in 15%, GPAC in 2%, and CoNS in 2%.

CONCLUSION

Cefazolin prophylaxis covers GPC and CoNS, but GNB with unreliable effectiveness. Gram-negative pathogens are increasingly reported in SSIs in high-risk patients. Adding prophylaxis for GNB in high-risk patients should be taken into account when considering spine surgery.

LEVEL OF EVIDENCE

IV.

Rabbit model of Staphylococcus aureus implant-associated spinal infection

Post-surgical implant-associated spinal infection is a devastating complication commonly caused by Staphylococcus aureus. Biofilm formation is thought to reduce penetration of antibiotics and immune cells, contributing to chronic and difficult-to-treat infections. A rabbit model of a posterior-approach spinal surgery was created, in which bilateral titanium pedicle screws were interconnected by a plate at the level of lumbar vertebra L6 and inoculated with a methicillin-resistant S.aureus (MRSA) bioluminescent strain. In vivo whole-animal bioluminescence imaging (BLI) and ex vivo bacterial cultures demonstrated a peak in bacterial burden by day 14, when wound dehiscence occurred. Structures suggestive of biofilm, visualized by scanning electron microscopy, were evident up to 56 days following infection. Infection-induced inflammation and bone remodeling were also monitored using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and computed tomography (CT). PET imaging signals were noted in the soft tissue and bone surrounding the implanted materials. CT imaging demonstrated marked bone remodeling and a decrease in dense bone at the infection sites. This rabbit model of implant-associated spinal infection provides a valuable preclinical in vivo approach to investigate the pathogenesis of implant-associated spinal infections and to evaluate novel therapeutics.

Summary: A model of post-surgical methicillin-resistant Staphylococcus aureus implant-associated spinal infection was created in rabbits, recapitulating acute infection as well as chronic low-burden infection, with structures suggestive of biofilm formation and bone remodeling.

Evaluating Trends and Outcomes of Spinal Deformity Surgery in Cerebral Palsy Patients

Background

There is a paucity of literature examining surgical trends and outcomes in both child and adult cerebral palsy (CP) patients. We aimed to evaluate surgical trends, complications, length of stay, and charges for spinal deformity surgery in CP patients.

Methods

Using the Nationwide Inpatient Sample (NIS) from 2001 to 2013, patients with CP scoliosis who underwent spinal fusion surgery were identified. Patient characteristics and comorbidities were recorded. Trends in spinal fusion approaches were grouped as anterior (ASF), posterior (PSF), or combined anterior-posterior (ASF/PSF). Complication rates, length of stay, and charges for each approach were analyzed. Bivariate analyses using adjusted Wald tests and multivariate analyses using linear (logarithmic transformation) and logistic regressions were performed.

Results

Of the 5191 adult CP patients who underwent spinal fusion the majority underwent PSF (86.5%), followed by the ASF/PSF approach (9.3%). The rate of PSF for cerebral palsy patients with spinal deformity increased significantly per 1 million people in the US population (0.90 to 1.30; P = .048). Complication rate, hospital length of stay, and charges were higher for patients undergoing ASF/PSF (P < .05). The overall complication rate for all surgical approaches was 25.7%. Patient comorbidities and combined ASF/PSF increased the odds of complication. Combined ASF/PSF was also associated with an increased length of stay and charges.

Conclusion

Combined ASF/PSF in patients with CP accounted for only 9.3% of surgical cases but was associated with the longest hospital stay, highest charges, and increased complications. Further scrutiny of the surgical indications and preoperative risk stratification should be undertaken to minimize complications, reduce length of stay, and decrease charges for CP patients undergoing spinal fusion.

Level of Evidence

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.

Gross Motor Function Classification System Specific Growth Charts-Utility as a Risk Stratification Tool for Surgical Site Infection Following Spine Surgery

BACKGROUND

There is currently minimal evidence that preoperative malnutrition increases surgical site infection (SSI) risk in children with cerebral palsy (CP) undergoing spinal deformity surgery. Growth charts specifically for patients with CP have been created to aid in the clinical interpretation of body mass index (BMI) as a marker of nutritional status, but to our knowledge these charts have never been used to risk stratify patients before orthopaedic surgery. We hypothesize that patients with CP who have BMI-for-age below the 10th percentile (BMI≤10) on CP-specific growth charts are at increased risk of surgical site infection following spinal deformity surgery compared with patients with BMI-for-age above the 10th percentile (BMI>10).

METHODS

Single-center, retrospective review comparing the rate of SSI in patients with CP stratified by BMI-for-age percentiles on CP-specific growth charts who underwent spinal deformity surgery. Odds ratios with 95% confidence intervals and Pearson χ tests were used to analyze the association of the measured nutritional indicators with SSI.

RESULTS

In total, 65 patients, who underwent 74 procedures, had complete follow-up data and were included in this analysis. Ten patients (15.4%) were GMFCS I-III and 55 (84.6%) were GMFCS IV-V; 39 (60%) were orally fed and 26 (40%) were tube-fed. The rate of SSI in this patient population was 13.5% with 10 SSIs reported within 90 days of surgery. There was a significant association between patients with a BMI below the 10th percentile on GMFCS-stratified growth charts and the development of SSI (OR, 13.6; 95% CI, 2.4-75.4; P=0.005). All SSIs occurred in patients that were GMFCS IV-V. There was no association between height, weight, feeding method, or pelvic instrumentation and development of SSI.

CONCLUSIONS

CP-specific growth charts are useful tools for identifying patients at increased risk for SSI following spinal instrumentation procedures, whereas standard CDC growth charts are much less sensitive. There is a strong association between preoperative BMI percentile on GMFCS-stratified growth charts and SSI following spinal deformity surgery.

LEVEL OF EVIDENCE

Level III-Retrospective Study.

Anatomic Trajectory for Iliac Screw Placement in Pediatric Scoliosis and Spondylolisthesis: An Alternative to S2-Alar Iliac Portal

STUDY DESIGN

Single-center retrospective study.

OBJECTIVE

To analyze two-year postoperative outcomes following spinopelvic fixation in pediatric patients using the anatomic trajectory (AT) portal for iliac screws.

SUMMARY

Iliac fixation is crucial in situations requiring fusion to sacrum. Challenges include complex anatomy, pelvic deformation, severe deformity, and previous surgery. The PSIS portal requires significant dissection, rod connectors, and complex bends. The SAI portal requires navigating the screw across the SI joint to the ilium. The anatomic trajectory (AT), first reported in 2009, is between the PSIS and SAI portal, without prominence, connectors, or complex bends.

METHODS

Fifty-four patients aged ≤18 years requiring instrumentation to the Ilium with minimum follow-up of two years (mean 44 months) were clinically and radiographically evaluated. Changes in coronal curve magnitude and pelvic obliquity were assessed using paired t test for patients with cerebral palsy. Spondylolisthesis reduction was assessed in patients with moderate- to high-grade spondylolisthesis (Meyerding grade 3 and 4).

RESULTS

A total of 108 iliac screws were inserted using AT portal in 54 patients. Twenty-eight neuromuscular and syndromic patients had an initial mean coronal curve of 85° corrected to 23° at two years (p < .001) and a pelvic obliquity of 22° corrected to 4° (p < .001). Twenty patients with moderate- to high-grade spondylolisthesis treated with reduction and interbody fixation improved significantly with respect to their slip angles (7° ± 14.7° to -7.9° ± 6.1°, p = .003). In the neuromuscular group, two surgical site infections occurred, two had implant fractures, and 12 had asymptomatic iliac screw loosening, none requiring revision. In the spondylolisthesis group, there were no neurologic complications and one had prominent screw requiring removal. Of 108 iliac screws, 2 rod connectors were employed.

CONCLUSION

Iliac screw insertion using the AT portal is a safe and effective method of pelvic fixation in pediatric patients with satisfactory radiographic correction and minimal complications.

LEVEL OF EVIDENCE

Level 4.

Caregiver Perceptions and Health-Related Quality-of-Life Changes in Cerebral Palsy Patients After Spinal Arthrodesis

STUDY DESIGN

A retrospective analysis of a prospective registry.

OBJECTIVE

Our objective was to prospectively assess caregivers' perceptions regarding changes in the health-related quality of life (HRQL) of patients with cerebral palsy (CP) after spinal arthrodesis. We assessed caregiver perceptions from three perspectives: 1) qualitative assessment of changes in global quality of life, comfort, and health; 2) relative valuation of spine surgery versus other common interventions in CP patients; and 3) quantitative changes in HRQL scores.

SUMMARY OF BACKGROUND DATA

Studies of children with CP who undergo surgical treatment of spinal deformity have focused largely on radiographic changes.

METHODS

We queried a multicenter prospective registry of CP patients with level IV or V motor function according to the Gross Motor Function Classification System who were treated with spinal arthrodesis, and whose caregivers completed preoperative and 2-year postoperative qualitative and quantitative HRQL surveys. A total of 212 caregivers and their patients were included in the study.

RESULTS

At 2-year follow-up, most caregivers reported that patients' global quality of life, comfort, and health were "a lot better" after spinal arthrodesis. Spinal arthrodesis was ranked as the most beneficial intervention in the patients' lives by 74% of caregivers, ahead of hip, knee, and foot surgeries and baclofen pump insertion. Gastrostomy tube insertion was the only intervention ranked superior to spinal arthrodesis in terms of impact. Quantitative HRQL scores improved significantly during 2-year follow-up across various domains.

CONCLUSION

In qualitative and quantitative HRQL assessments, caregivers reported overall improvement in patients' lives after spinal arthrodesis. Caregivers ranked spine surgery as the most beneficial intervention in the patients' lives, secondary only to gastrostomy tube insertion.

LEVEL OF EVIDENCE

2.

Perioperative complications and risk factors in neuromuscular scoliosis surgery

OBJECTIVE High rates of perioperative complications are associated with deformity correction in neuromuscular scoliosis. The current study aimed to evaluate complications associated with surgical correction of neuromuscular scoliosis and to characterize potential risk factors. METHODS Data were retrospectively collected from a single-center cohort of 102 consecutive patients who underwent spinal fusions for neuromuscular scoliosis between January 2008 and December 2016 and who had a minimum of 6 months of follow-up. A subgroup analysis was performed on data from patients who had at least 2 years of follow-up. Univariate and multivariate regression analyses, as well as binary correlational models and Student t-tests, were employed for further statistical analysis. RESULTS The present cohort had 53 boys and 49 girls with a mean age at surgery of 14.0 years (± 2.7 SD, range 7.5-19.5 years). The most prevalent diagnoses were cerebral palsy (26.5%), spinal cord injury (24.5%), and neurofibromatosis (10.8%). Analysis reflected an overall perioperative complication rate of 27% (37 complications in 27 patients), 81.1% of which constituted major complications (n = 30) compared to a rate of 18.9% for minor complications (n = 7). Complications were predicted by nonambulatory status (p = 0.037), increased intraoperative blood loss (p = 0.012), increased intraoperative time (p = 0.046), greater pelvic obliquity at follow-up (p = 0.028), and greater magnitude of sagittal profile at follow-up (p = 0.048). Pulmonary comorbidity (p = 0.001), previous operations (p = 0.013), history of seizures (p = 0.046), diagnosis of myelomeningocele (p = 0.046), increase in weight postoperatively (p < 0.005), and increased lumbar lordosis at follow-up (p = 0.015) were identified as risk factors for perioperative infection. CONCLUSIONS These results suggest that in neuromuscular scoliosis, patients with preexisting pulmonary compromise and greater intraoperative blood loss have the greatest risk of experiencing a major perioperative complication following surgical deformity correction.

Multivariate Analysis and Machine Learning in Cerebral Palsy Research

Cerebral palsy (CP), a common pediatric movement disorder, causes the most severe physical disability in children. Early diagnosis in high-risk infants is critical for early intervention and possible early recovery. In recent years, multivariate analytic and machine learning (ML) approaches have been increasingly used in CP research. This paper aims to identify such multivariate studies and provide an overview of this relatively young field. Studies reviewed in this paper have demonstrated that multivariate analytic methods are useful in identification of risk factors, detection of CP, movement assessment for CP prediction, and outcome assessment, and ML approaches have made it possible to automatically identify movement impairments in high-risk infants. In addition, outcome predictors for surgical treatments have been identified by multivariate outcome studies. To make the multivariate and ML approaches useful in clinical settings, further research with large samples is needed to verify and improve these multivariate methods in risk factor identification, CP detection, movement assessment, and outcome evaluation or prediction. As multivariate analysis, ML and data processing technologies advance in the era of Big Data of this century, it is expected that multivariate analysis and ML will play a bigger role in improving the diagnosis and treatment of CP to reduce mortality and morbidity rates, and enhance patient care for children with CP.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

Level IV-therapeutic.

Sacral-Alar-Iliac Fixation in Children with Neuromuscular Scoliosis: Minimum 5-Year Follow-Up

OBJECTIVE

To investigate the 5-year outcomes of children with neuromuscular scoliosis treated with sacral-alar-iliac screws.

METHODS

We reviewed clinical and radiographic records of patients aged ≤18 years treated by 1 pediatric orthopedic surgeon for neuromuscular scoliosis with spinal fusion using sacral-alar-iliac pelvic anchors. Thirty-eight patients with a minimum 5-year radiographic follow-up (mean, 6.0 ± 1.2 years) were studied. The mean patient age was 13 ± 2.0 years, and 47% were female. The mean number of levels fused was 18 ± 0.7. Two-thirds (66%) of the patients were diagnosed with cerebral palsy.

RESULTS

Between the preoperative period and final follow-up, the patients exhibited a mean correction of the major coronal curve of 79% (preoperative, 85° to final, 18°) and a mean 57% correction of the pelvic obliquity (preoperative, 16° to final, 7°). Patients maintained the correction of mean pelvic obliquity from the early postoperative period (6°) to final follow-up (7°). Preoperatively, 76% of the patients had a pelvic obliquity of >10°, compared with 26% of patients postoperatively. There were no cases of neurologic or vascular complications or pseudarthrosis. Radiographs revealed bilateral sacral-alar-iliac screw lucency in 8 patients; 4 of these patients had deep wound infections, and the other 4 were asymptomatic. Unilateral screw fracture was found in 1 patient with an 8-mm-diameter screw (1.3%; 1 of 76 screws); the patient was observed and remained asymptomatic. There were no cases of set screw displacement, screw back-out, or rod dislodgement.

CONCLUSIONS

Sacral-alar-iliac screws are safe and effective pelvic anchors for use in children with neuromuscular scoliosis.

Outcomes after scoliosis surgery for children with cerebral palsy: a systematic review

AIM

This study aims (1) to evaluate and synthesize the evidence for the postoperative outcomes after scoliosis surgery for children with cerebral palsy (CP), and (2) to identify preoperative risk factors for adverse outcomes after surgery.

METHOD

Medline, EMBASE, CINAHL, and PubMed were searched for relevant literature. Included studies were assessed for risk of bias using the Cochrane Effective Practice and Organisation of Care tool. Quality of evidence for overall function, quality of life (QoL), gross motor function, caregiver outcomes, deformity correction, and postoperative complications were assessed using GRADE (Grades of Recommendation, Assessment, Development and Evaluation).

RESULTS

Fifty-one studies met inclusion criteria, including 35 case series designs. Risk of bias was high across all studies. On average good deformity correction was achieved, the trend appears positive for caregiver and QoL outcomes, but there was minimal to no change for gross motor or overall function. Inconsistent measurement limited synthesis. A mean overall complication rate of 38.1% (95% confidence interval 27.3-53.3) was found. The quality of evidence was very low across all functional outcomes.

INTERPRETATION

Limited high-quality evidence exists for outcomes after scoliosis surgery in children with CP, a procedure associated with a moderately high complication rate. The intervention appears indicated for deformity correction, but currently there is insufficient evidence to make recommendations for this surgery as a way to also improve functional outcomes, caregiver outcomes, and quality of life.

Recurrence of Deep Surgical Site Infection in Cerebral Palsy After Spinal Fusion Is Rare

STUDY DESIGN

Retrospective review of prospective registry.

OBJECTIVES

To assess the following in children with cerebral palsy (CP) who develop deep surgical site infection (DSSI) after spinal fusion: (1) rate of infection recurrence after treatment; (2) treatments used; (3) radiographic outcomes; and (4) differences in Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) scores versus those of children with no infection (NI).

SUMMARY OF BACKGROUND DATA

Studies show high rates of surgical site infection in patients with CP but do not address late recurrence or quality-of-life effects.

METHODS

One hundred fifty-one children with CP underwent spinal fusion surgery from 2008 through 2011 and had ≥2-year follow-up. Patients who developed DSSI were compared with patients with NI. Student t tests were used to analyze deformity; analysis of variance was used to analyze CPCHILD scores in both groups preoperatively and at final follow-up.

RESULTS

Eleven patients developed DSSI. Causative organisms were polymicrobial infection (5 cases), Escherichia coli (2 cases), and Proteus mirabilis, Staphylococcus aureus, Enterococcus faecalis, and Peptostreptococcus (1 case each). All patients underwent irrigation and debridement and received at least 6 weeks of antibiotics. Six had negative-pressure-dressing-assisted wound closure; 5 had primary closure. At mean 4-year follow-up (range, 3-5 years) no patient had recurrent infection. From immediate postoperative to final follow-up, no patient had significant loss of coronal curve (p = .77) or pelvic obliquity (p = .71) correction. However, at final follow-up, comfort and emotions, overall quality-of-life, and total CPCHILD scores in the DSSI group were significantly lower compared with the NI group (p = .005, .022, and .026, respectively).

CONCLUSIONS

In children with CP who developed DSSI after spinal fusion, there was no recurrence of infection or deformity after infection treatment. CPCHILD scores in patients with DSSI were lower compared with the NI group.

Epidemiology of Deep Surgical Site Infections After Pediatric Spinal Fusion Surgery

STUDY DESIGN

Single-institution, retrospective case series.

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

4.

Management of spinal infections in children with cerebral palsy

Cerebral palsy patients who undergo posterior spinal instrumentation for scoliosis are at a greater risk of surgical site infection compared to adolescents with idiopathic scoliosis. Many infecting organisms are reported. Risk factors include patients' specific factors, nutritional status as well as surgery related factors. Although surgical management is still controversial, it is always based on irrigation and debridement followed or not by implant removal. The purpose of this paper is to review the pathophysiology of surgical site infection in this patient population and to propose a treatment algorithm, based on a thorough review of the current literature and personal experience.

What's New in the Management of Neuromuscular Scoliosis

BACKGROUND

Patients with neuromuscular scoliosis (NMS) can pose treatment challenges related to medical comorbidities and altered spinopelvic anatomy. We reviewed the recent literature regarding evaluation and management of NMS patients and explored areas where further research is needed.

METHODS

We searched the PubMed database for all papers related to the treatment of NMS published from January 1, 2011 through July 31, 2014, yielding 70 papers.

RESULTS

A total of 39 papers contributed compelling new findings. Steroid treatment has been most promising in patients with Duchenne muscular dystrophy, leading to a significantly lower death rate, better pulmonary function, and longer independent ambulation. Growing rods in early-onset NMS were shown to result in significant improvements in major Cobb angles and pelvic obliquity, with low complication rates in patients with spinal muscular atrophy but high infection rates in those with cerebral palsy. Early reports of magnetic growing rods in NMS patients are favorable. Intraoperative neural monitoring is variable in this patient population; however, use of transcranial motor-evoked potentials in NMS patients seems to be safe. Blood loss is the highest in NMS patients when compared with all other diagnostic categories. However, tranexamic acid seems to significantly lower intraoperative blood loss. In a multicenter study, patients diagnosed with NMS had the highest surgical-site infection rate at 13.1%. Best-practice guidelines have been created regarding prevention of infection in NMS patients. Preoperative nutritional optimization and postoperative nutritional supplementation seem to help with lowering the infection rate in these patients.

CONCLUSIONS

There have been major advances in the management of NMS patients, but many challenges remain. Further multicenter studies and randomized clinical trials are needed, particularly in the areas of infection prophylaxis, nutritional optimization, improvement in intraoperative neural monitoring, and prevention of proximal junctional kyphosis.

LEVEL OF EVIDENCE

Level 4-literature review.

What Is the Impact of Center Variability in a Multicenter International Prospective Observational Study on Developmental Dysplasia of the Hip?

BACKGROUND

Little information exists concerning the variability of presentation and differences in treatment methods for developmental dysplasia of the hip (DDH) in children < 18 months. The inherent advantages of prospective multicenter studies are well documented, but data from different centers may differ in terms of important variables such as patient demographics, diagnoses, and treatment or management decisions. The purpose of this study was to determine whether there is a difference in baseline data among the nine centers in five countries affiliated with the International Hip Dysplasia Institute to establish the need to consider the center as a key variable in multicenter studies.

QUESTIONS/PURPOSES

(1) How do patient demographics differ across participating centers at presentation? (2) How do patient diagnoses (severity and laterality) differ across centers? (3) How do initial treatment approaches differ across participating centers?

METHODS

A multicenter prospective hip dysplasia study database was analyzed from 2010 to April 2015. Patients younger than 6 months of age at diagnosis were included if at least one hip was completely dislocated, whereas patients between 6 and 18 months of age at diagnosis were included with any form of DDH. Participating centers (academic, urban, tertiary care hospitals) span five countries across three continents. Baseline data (patient demographics, diagnosis, swaddling history, baseline International Hip Dysplasia Institute classification, and initial treatment) were compared among all nine centers. A total of 496 patients were enrolled with site enrolment ranging from 10 to 117. The proportion of eligible patients who were enrolled and followed at the nine participating centers was 98%. Patient enrollment rates were similar across all sites, and data collection/completeness for relevant variables at initial presentation was comparable.

RESULTS

In total, 83% of all patients were female (410 of 496), and the median age at presentation was 2.2 months (range, 0-18 months). Breech presentation occurred more often in younger (< 6 months) than in older (6-18 months at diagnosis) patients (30% [96 of 318] versus 9% [15 of 161]; odds ratio [OR], 4.2; 95% confidence interval [CI], 2.3-7.5; p < 0.001). The Australia site was underrepresented in breech presentation in comparison to the other centers (8% [five of 66] versus 23% [111 of 479]; OR, 0.3, 95% CI, 0.1-0.7; p = 0.034). The largest diagnostic category was < 6 months, dislocated reducible (51% [253 of 496 patients]); however, the Australia and Boston sites had more irreducible dislocations compared with the other sites (ORs, 2.1 and 1.9; 95% CIs, 1.2-3.6 and 1.1-3.4; p = 0.02 and 0.015, respectively). Bilaterality was seen less often in older compared with younger patients (8% [seven of 93] versus 26% [85 of 328]; p < 0.001). The most common diagnostic group was Grade 3 (by International Hip Dysplasia Institute classification), which included 58% (51 of 88) of all classified dislocated hips. Splintage was the primary initial treatment of choice at 80% (395 of 496), but was far more likely in younger compared with older patients (94% [309 of 328] versus 18% [17 of 93]; p < 0.001).

CONCLUSIONS

With the lack of strong prognostic indicators for DDH identified to date, the center is an important variable to include as a potential predictor of treatment success or failure.

Sacral-Alar-Iliac Fixation in Pediatric Deformity: Radiographic Outcomes and Complications

STUDY DESIGN

Retrospective case series.

OBJECTIVES

To assess the radiographic outcomes and complications of sacral-alar-iliac (SAI) fixation in children.

SUMMARY OF BACKGROUND DATA

Pelvic fixation in children undergoing spinal deformity surgery can be challenging because of complex anatomy, compound biomechanical forces at the lumbosacral junction, and poor bone quality.

METHODS

Radiographic and clinical records of 80 consecutive patients aged 18 years or younger who underwent posterior spinal fusion surgery with SAI fixation by one pediatric orthopedic surgeon and who had a minimum 2 years of follow-up (mean follow-up: 3.5 years, range, 2-7 years) were retrospectively reviewed. Changes in coronal curve magnitude and pelvic obliquity were assessed using Student t tests. Significance was set at a p value less than .05 for all analyses.

RESULTS

Pelvic obliquity correction averaged 77%, from 26 ± 13 degrees before surgery to 6 ± 4 degrees at final follow-up (p < .001); 91% of the patients were corrected to a pelvic obliquity of less than 10 degrees. Coronal curve correction averaged 72%, from 78 ± 27 degrees before surgery to 22 ± 15 degrees at final follow-up (p < .001). No patient had vascular or neurologic complications or died perioperatively. Twenty patients (25%) had radiographic evidence of implant-related problems, of which there were nine screw fractures (all in the neck of screws with ≤8-mm outer diameter). Six patients had symptomatic complications associated with SAI fixation (three patients with pseudarthrosis at the lumbosacral junction, all of whom required revision surgery, two patients with implant prominence, and one patient with pain related to implant). Other complications included seven instances of wound dehiscence, three deep wound infections, and one superficial wound infection.

CONCLUSIONS

SAI fixation provided a low-profile alternative to iliac screws for the correction of pelvic obliquity. The largest possible diameter screws are recommended, ideally >8 mm.

LEVEL OF EVIDENCE

Level 4.

Intraoperative Cardiopulmonary Arrest in Children Undergoing Spinal Deformity Correction: Causes and Associated Factors

STUDY DESIGN

Retrospective review.

OBJECTIVE

To report the incidence of and risk factors for intraoperative cardiopulmonary arrest (ICA) in children undergoing spinal deformity surgery.

SUMMARY OF BACKGROUND DATA

Spinal deformities in children are associated with comorbidities that can pose substantial risks during surgery.

METHODS

We reviewed records of patients who underwent surgery at two pediatric tertiary-care hospitals from 2004 through 2014. Fisher exact test and the Student t test were used to compare ICA and non-ICA groups by patient diagnosis, estimated blood loss, number of vertebral levels fused, and proportion of blood volume lost (significance, P < 0.05). We classified proximate causes of ICA based on hemoglobin, metabolic panel/electrolyte imbalance, electrocardiogram/echocardiography, and vital signs.

RESULTS

ICA occurred in 11 of 2524 (0.4%) patients. Patients with neuromuscular disorders had a 3-fold higher risk of ICA compared with those without neuromuscular disorders. At the time of ICA, hemoglobin levels were 5  g/dL or less in four patients, potassium was higher than 5.5  mEq/L in six patients, and ionized calcium was less than or equal to 1  mmol/L in two patients. There were significant differences between the ICA and non-ICA groups in mean number of vertebral levels fused (15 vs. 12), patient weight (34 vs. 49  kg), estimated blood loss (2623 vs. 959  mL), and proportion of blood volume lost (1.03 vs. 0.33) (all P < 0.01). Suspected causes of ICA were cardiovascular causes (eight patients) and anaphylaxis, primary rhythm disturbance, and respiratory/airway cause (one patient each). The incidence of ICA for patients with idiopathic scoliosis was 0.13%. Ten of the 11 patients were successfully resuscitated, and one patient died.

CONCLUSION

ICA occurs in approximately 0.4% of children undergoing spinal fusion surgery. Patients with neuromuscular disorders are at greater risk of ICA than those without these disorders.

LEVEL OF EVIDENCE

3.

Unplanned Hospital Readmissions and Reoperations After Pediatric Spinal Fusion Surgery

STUDY DESIGN

Retrospective review.

OBJECTIVE

To investigate the rates and reasons for unplanned readmissions and reoperation after pediatric spinal fusion surgery at our institution and to identify risk factors by analyzing patient and surgical characteristics. Unplanned readmission and reoperation were defined as unplanned events within 90 days of the index surgery.

SUMMARY OF BACKGROUND DATA

The rate of unplanned readmission and reoperation after pediatric spinal fusion surgery is not well established.

METHODS

Clinical records were reviewed for all children who underwent spinal fusion surgical procedures for spinal deformity correction performed by 1 surgeon from 2000 through 2013 at our institution. Inclusion criteria were age of 10 to 18 years at surgery, fusion spanning more than 5 vertebral levels, and 3 months of clinical or radiographical follow-up (1002 patients met these criteria). Univariate and multivariate logistic regression models were created. Statistical significance was set at a P value of less than 0.05 for all analyses.

RESULTS

The overall 90-day unplanned readmission and reoperation rates were 8.0% and 3.8%, respectively. The most common causes of readmission were wound dehiscence (1.8%), deep wound infection (1.5%), pulmonary complications (1%), and superficial wound infection (0.9%). Univariate analysis showed that readmission was significantly associated with a higher number of levels fused, greater estimated blood loss, longer length of stay, and certain diagnoses; reoperation was significantly associated with a higher number of levels fused and certain diagnoses. On multivariate analysis, only patient diagnosis was found to be significantly associated with readmission and reoperation; patients with congenital scoliosis, genetic or syndromic scoliosis, cerebral palsy, and other neuromuscular disorders had significantly higher rates.

CONCLUSION

Unplanned readmission rate after pediatric spinal fusion surgery was 8%, most commonly for wound dehiscence and deep and superficial infections. Increased intraoperative blood loss, higher number of levels fused, and certain diagnoses are risk factors for unplanned readmission.

LEVEL OF EVIDENCE

4.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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