Unanticipated revision surgery in adolescent idiopathic scoliosis

Revision Surgery After Spinal Fusion in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective Aanalysis of a Large Cohort of Cases.

OBJECTIVES

To explore the rate and cause of revision surgery after spinal fusion in adolescent idiopathic scoliosis(AIS).

METHODS

The patients diagnosed with AIS who underwent spinal fusion surgery in a single center from 2002 to 2018 were retrospectively analyzed. All the patients were followed up at least 2 years. The causes of revision surgery were analyzed and the incidence of revision surgery was counted.

RESULTS

A total of 1816 AIS patients were included in the study. After an average of 8.5 years (range 3-18 years) follow-up, a total of 51 patients underwent 54 revision operations. The overall revision rate is 2.8%. The revision rate of combined approach (anterior and posterior) and anterior approach was 6.6% (8/122), and the revision rate of posterior approach was 2.5% (43/1694). The most common causes of revision were malposition of implants/implants failure (37%), followed by poor wound healing/ infection (23%). Spinal decompensation, adding on and proximal junctional kyphosis (PJK) accounted for 20%. The compensatory curve continued to worsen after selective fusion accounted for 14% and finally the discomfort with the implants accounted for 6%.

CONCLUSIONS

The overall revision rate of spinal fusion for AIS is 2.8%. The implants and incision problems were the most common causes of revision surgeries.

Navigation-Assisted One-Staged Posterior Spinal Fusion Using Pedicle Screw Instrumentation in Adolescent Idiopathic Scoliosis-A Case Series

Background and Objectives: Adolescent idiopathic scoliosis (AIS) is a prevalent three-dimensional spinal disorder, with a multifactorial pathogenesis, including genetics and environmental aspects. Treatment options include non-surgical and surgical treatment. Surgical interventions demonstrate positive outcomes in terms of deformity correction, pain relief, and improvements of the cardiac and pulmonary function. Surgical complications, including excessive blood loss and neurologic deficits, are reported in 2.27-12% of cases. Navigation-assisted techniques, such as the O-arm system, have been a recent focus with enhanced precision. This study aims to evaluate the results and complications of one-stage posterior instrumentation fusion in AIS patients assisted by O-arm navigation. Materials and Methods: This retrospective study assesses 55 patients with AIS (12-28 years) who underwent one-stage posterior instrumentation correction supported by O-arm navigation from June 2016 to August 2023. We examined radiological surgical outcomes (initial correction rate, loss of correction rate, last follow-up correction rate) and complications as major outcomes. The characteristics of the patients, intraoperative blood loss, operation time, number of fusion levels, and screw density were documented. Results: Of 73 patients, 55 met the inclusion criteria. The average age was 16.67 years, with a predominance of females (78.2%). The surgical outcomes demonstrated substantial initial correction (58.88%) and sustained positive radiological impact at the last follow-up (56.56%). Perioperative complications, including major and minor, occurred in 18.18% of the cases. Two patients experienced a major complication. Blood loss (509.46 mL) and operation time (402.13 min) were comparable to the literature ranges. Trend analysis indicated improvements in operation time and blood loss over the study period. Conclusions: O-arm navigation-assisted one-stage posterior instrumentation proves reliable for AIS corrective surgery, achieving significant and sustained positive radiological outcomes, lower correction loss, reduced intraoperative blood loss, and absence of implant-related complications. Despite the challenges, our study demonstrates the efficacy and maturation of this surgical approach.

Investigating the Differential Circulating microRNA Expression in Adolescent Females with Severe Idiopathic Scoliosis: A Proof-of-Concept Observational Clinical Study

Adolescent Idiopathic Scoliosis (AIS) is the most common form of three-dimensional spinal disorder in adolescents between the ages of 10 and 18 years of age, most commonly diagnosed in young women when severe disease occurs. Patients with AIS are characterized by abnormal skeletal growth and reduced bone mineral density. The etiology of AIS is thought to be multifactorial, involving both environmental and genetic factors, but to date, it is still unknown. Therefore, it is crucial to further investigate the molecular pathogenesis of AIS and to identify biomarkers useful for predicting curve progression. In this perspective, the relative abundance of a panel of microRNAs (miRNAs) was analyzed in the plasma of 20 AIS patients and 10 healthy controls (HC). The data revealed a significant group of circulating miRNAs dysregulated in AIS patients compared to HC. Further bioinformatic analyses evidenced a more restricted expression of some miRNAs exclusively in severe AIS females. These include some members of the miR-30 family, which are considered promising regulators for treating bone diseases. We demonstrated circulating extracellular vesicles (EVs) from severe AIS females contained miR-30 family members and decreased the osteogenic differentiation of mesenchymal stem cells. Proteomic analysis of EVs highlighted the expression of proteins associated with orthopedic disease. This study provides preliminary evidence of a miRNAs signature potentially associated with severe female AIS and suggests the corresponding vesicular component may affect cellular mechanisms crucial in AIS, opening the scenario for in-depth studies on prognostic differences related to gender and grade.

Repeat surgical interventions following "definitive" instrumentation and fusion for idiopathic scoliosis: a 30-year update

PURPOSE

Although spinal fusion (SF) is considered "definitive" treatment in juvenile/adolescent idiopathic scoliosis (JIS/AIS), complications requiring reoperation continue to occur. The purpose of this study was to characterize the evolving rates of reoperation following SF in JIS/AIS.

METHODS

Single-center retrospective review of patients who underwent SF for JIS/AIS as their index surgical treatment between 2013 and 2019. Patient data were collected to identify complications requiring reoperation and factors associated with reoperation. Complication rates from 2013 to 2019 were compared to patients from 1988 to 2012 at the same institution.

RESULTS

This study analyzed 934 patients (81.7% female, mean age at surgery 14.5 ± 2.1). Thirty-eight patients (4.1%) required a total of 47 reoperations, a > 50% decrease in overall complication rate from the 2008-2012 population (4.1% vs 9.6%, respectively, p < 0.001). The decrease stemmed mainly from decreases in rates of infection (1.1% vs 4.1%, p < 0.001) and symptomatic implants (0.4% vs 2.1%, p = 0.004). There were, however, non-significant increases in implant failures (0.6% vs 0.2%, p = 0.4367) and pseudoarthrosis (1.0% vs 0.4%, p = 0.5202). Both of these complications were associated with patients with a higher mean weight (implant failure: 70.4 kg ± 21.1 vs 56.1 kg ± 14.9, p = 0.002; pseudoarthrosis: 85.8 kg ± 27.9 vs 55.9 ± 14.5, p = 0.001).

CONCLUSIONS

Reoperation following SF for JIS/AIS has decreased over the past 7 years when compared to 25 years of historical controls. The changing landscape of reoperation demands further research into the risk factors for those reoperations that have become more common.

Benefits of Best Practice Guidelines in Spine Fusion: Comparable Correction in AIS with Higher Density and Fewer Complications

BACKGROUND

There is significant variability in surgeons' instrumentation patterns for adolescent idiopathic scoliosis surgery. Implant density and costs are difficult to correlate with deformity correction, safety, and quality of life measures.

MATERIALS AND METHODS

Two groups of postoperative adolescents were compared based on exposure to a best practice guidelines program (BPGP) introduced to decrease complications. Hybrid and stainless steel constructs were dropped, and posterior-based osteotomies, screws, and implant density were increased to 66.8 ± 12.03 vs. 57.5 ± 16.7% (p < 0.001). The evaluated outcomes were: initial and final correction, rate of correction loss, complications, OR returns, and SRS-22 scores (minimum two-year follow-up).

RESULTS

34 patients were operated on before BPGP and 48 after. The samples were comparable, with the exceptions of a higher density and longer operative times after BPGP. Initial and final corrections before BPGP were 67.9° ± 22.9 and 64.6° ± 23.7; after BPGP, the corrections were 70.6° ± 17.4 and 66.5° ± 14.9 (sd). A regression analysis did not show a relation between the number of implants and postoperative correction (beta = -0.116, p = 0.307), final correction (beta = -0.065, p = 0.578), or loss of correction (beta= -0.137, p = 0.246). Considering screw constructs only (n = 63), a regression model controlled for flexibility continued to show a slight negative effect of density on initial correction (b = -0.274; p = 0.019). Only with major curve concavity was density relevant in initial correction (b = 0.293; p = 0.038), with significance at 95% not being achieved for final correction despite a similar beta (b = 0.263; p = 0.069). Complications and OR returns dropped from 25.6% to 4.2%. Despite this, no difference was found in SRS-22 (4.30 ± 0.432 vs. 4.42 ± 0.39; sd) or subdomain scores pre- and post-program.

FINDINGS

Although it appears counterintuitive that higher density, osteotomies, and operative time may lead to fewer complications, the study shows the value of best practice guidelines in spinal fusions. It also shows that a 66% implant density leads to better safety and efficacy, avoiding higher costs.

Minimally invasive surgery using posterior-only Pedicle screw fixation in treatment of Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-Analysis

Minimally invasive surgery (MIS) techniques for posterior spine pedicle-screw fusion (PSF) may reduce the AIS surgery invasiveness, although they require a certain degree of patient selection based on the severity of the curve. The aim of this article is to systematically review the Literature to determine efficacy and safety of MIS-PSF in AIS correction, and to compare its outcomes with open-PSF. A systematic search of electronic databases from eligible articles was conducted. Only studies adopting MIS-PSF for AIS were included. Clinical and radiographic outcomes were extracted and summarized. Meta-analyses were performed. P-value < 0.05 was considered significant. Thirteen studies for a total of 635 patients ungergoing MIS-PSF were included in this review. Pre-operative Cobb's angle ranged from 48.3°±4.2° to 59.8°±6.6°, coronal correction from 58.1% to 79.1%, average operative time ranged from 252 to 526.8 min, average estimated blood loss from 138.8 ± 50 to 1250 mL. Sixty-seven complications were recorded (9.9%), with 19 revisions (3.8%), resulting similar to those described in Literature using open-PSF. At meta-analysis, MIS-PSF (321 patients) compared to open-PSF (429 patients) showed lower coronal correction (although no statistically significant difference was found), estimated blood loss and length of hospital stay, but higher operative time. No differences in SRS-22, complications and revision rate were found. In conclusion, open-PSF shows a trend towards higher correction in the coronal plane and requires a shorter operative time when compared to MIS-PSF. It remains the gold standard for AIS correction, although MIS-PSF seems to be a viable and promising technique for selected patients. - KEYWORDS: minimally invasive surgery, minimally invasive techniques, adolescent idiopathic scoliosis, posterior spinal fusion, pedicle-screws-only instrumentation.

The Impact of Unplanned Return to the Operating Room on Health-related Quality of Life at the End of Growth-friendly Surgical Treatment for Early-onset Scoliosis

BACKGROUND

Limiting complications, especially unplanned return to the operating room (UPROR), is a major focus in the surgical management of early-onset scoliosis (EOS). Although UPROR remains common in this population, its effect on long-term health-related quality of life (HRQoL) remains unclear. The purpose of this study was to investigate the association between UPROR and end-of-treatment HRQoL in EOS patients treated with growth-friendly instrumentation.

METHODS

Patients with EOS who underwent growth-friendly instrumentation at age less than 10 years from 1993 to 2018, and completed treatment, were identified in a multicenter EOS registry. UPROR events were recorded, and end-of-treatment (defined as skeletal maturity and/or definitive spinal fusion) HRQoL was assessed via the 24-item Early-Onset Scoliosis Questionnaire (EOSQ-24).

RESULTS

A total of 825 patients were identified, and 325 patients (age at surgery: 6.4 y, follow-up: 8.1 y) had end-of-treatment HRQoL data necessary for our investigation. Overall, 129/325 (39.7%) patients experienced 264 UPROR events; the majority (54.2%) were implant-related. Aside from age and etiology, no other variables were determined to be confounders or effect modifiers. Congenital patients with UPROR had worse pain/discomfort by 10.4 points (P=0.057) and worse pulmonary function by 7.8 points (P=0.102) compared with non-UPROR patients adjusting for age. Neuromuscular patients with UPROR had worse pulmonary function by 10.1 points compared with non-UPROR patients adjusting for age (P=0.037). Idiopathic and syndromic patients with UPROR reported consistently worse domain scores than their non-UPROR counterparts, but smaller (<5-point) differences were seen.

CONCLUSIONS

UPROR during growth-friendly surgical treatment for EOS is associated with worse HRQoL in all patients, but particularly in those with neuromuscular or congenital etiologies. Ongoing efforts to avoid UPROR are critical.

LEVEL OF EVIDENCE

Level II. This is a multicenter retrospective cohort study investigating the effect of UPROR on HRQoL (prognostic study).

Cost-utility Analysis Comparing Bracing Versus Observation for Skeletally Immature Patients with Thoracic Scoliosis

STUDY DESIGN

Cost-utility analysis.

OBJECTIVE

This study aimed to investigate the cost-utility of bracing versus observation in patients with thoracic scoliosis who would be indicated for bracing.

SUMMARY OF BACKGROUND DATA

There is high-quality evidence that bracing can prevent radiographic progression of spinal curvature in adolescent idiopathic scoliosis (AIS) patients with curves between 25° and 40° and Risser 0 to 2 skeletal maturity index. However, to our knowledge, the cost-utility of bracing in AIS has not been established.

METHODS

A decision-analysis model comparing bracing versus observation was developed for a hypothetical 10-year old girl (Risser 0, Sanders 3) with a 35° main thoracic curve. We estimated the probability, cost, and quality-adjusted life years (QALY) for each node based on comprehensive review of the literature. Costs were adjusted for inflation based on Consumer Price Index and reported in terms of 2020 real dollars. Incremental net monetary benefit (INMB) was calculated based on a probabilistic sensitivity analysis using Monte Carlo simulations of 1000 hypothetical patients. One-way sensitivity analyses were performed by varying cost, probability, and QALY estimates.

RESULTS

Our decision-analysis model revealed that bracing was the dominant treatment choice over observation at $50,000/QALY willingness to pay threshold. In simulation analysis of a hypothetical patient cohort, bracing was associated with lower net lifetime costs ($60,377 ± $5,340 with bracing vs. $85,279 ± $4543 with observation) and higher net lifetime QALYs (24.1 ± 2.0 with bracing vs. 23.9 ± 1.8 with observation). Bracing was associated with an INMB of $36,093 (95% confidence interval $18,894-$55,963) over observation over the patient's lifetime. The model was most sensitive to the impact of bracing versus observation on altering the probability of requiring surgery, either as an adolescent or an adult.

CONCLUSION

Cost-utility analysis supports scoliosis bracing as the preferred choice in management of appropriately indicated AIS patients with thoracic scoliosis.Level of Evidence: 5.

Preoperative Thoracic Curve Magnitude and L4 End Vertebra Were Risk Factors for Subjacent Disc Wedging After Selective Thoracolumbar/Lumbar Fusion with L3 as the Lowest Instrumented Vertebra in Lenke Type 5 Curve Patients

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVE

This study aimed to investigate the incidence and risk factors of subjacent disc wedging (SDW) in adolescent idiopathic scoliosis (AIS) patients with Lenke type 5 curve.

SUMMARY OF BACKGROUND DATA

SDW is frequently observed after surgery; however, data about its mechanism and relations with outcome are limited.

METHODS

Data of 59 patients with AIS with Lenke type 5 curves who underwent posterior spinal fusion to L3 as the lowest instrumented vertebra (LIV) were retrospectively analyzed. The subjacent disc angle (SDA) was defined as the angle between L3 (LIV) and L4. SDW was defined as the absolute value of SDA of 10° or higher 2 years postoperatively. The incidence of SDW was investigated between nonselective and selective thoracolumbar/lumbar (TL/L) fusion group. In the selective group, patients with and without SDW were compared.

RESULTS

Among 59 patients, 11 had nonselective and 48 had selective fusion. No patients in the nonselective group showed SDW versus 13 patients in the selective group (27%) showed SDW. In the selective group, patients with SDW showed significantly greater main thoracic curve, apical vertebral translation of the main thoracic curve, upper instrumented vertebra tilt, LIV tilt, and SDA 2 years postoperatively, whereas no differences were found in the coronal balance or clinical outcome. Multivariate analysis revealed preoperative T curve and SDA as predictors of SDW occurrence. T curve greater than 30° and SDA greater than 0° were calculated as cutoff values based on the receiver operating characteristic curve.

CONCLUSION

SDW is sometimes seen in Lenke type 5 patients with AIS who underwent selective TL/L fusion. SDW seemed to occur as a compensation mechanism for progressing deformity of unfused segments (thoracic curve and residual lumbar curve) to maintain coronal alignment. Preoperative T curve > 30° and SDA > 0° (lower-end vertebra as L4) were determined as risk factors for SDW occurrence.Level of Evidence: 3.

Development of a Shared Decision-Making Tool for Adolescents With Scoliosis to Decide Between Observation Versus Fusion Surgery

BACKGROUND

Adolescent patients with moderate to severe idiopathic scoliosis who have completed their skeletal growth face a significant choice in their treatment path: watchful waiting or spinal fusion. Shared decision making (SDM) assists patients and clinicians to find treatments that make intellectual, practical and emotional sense. Our objective was to develop a tool that supports SDM for patients with scoliosis and their families.

METHODS

We used a user-centered design approach that included collaboration between patients, surgeons and SDM experts, observation of clinician encounters, and literature review. We focused on adolescent idiopathic scoliosis patients 13 or more years of age with less than 1 year of growth remaining (Risser stage 3 or greater) and curves between 40 and 65 degrees.

RESULTS

We included 22 patients, and collected 22 video recordings. From these videos, we identified salient patient priorities for decision making including treatment benefits, surgical complications, pain, scheduling and recovery, and cost. For each theme, we conducted a focused review to obtain the best estimate of effect. Then, an expert SDM designer developed an electronic prototype called Scoliosis Choice.

CONCLUSIONS

The initial prototype of the scoliosis SDM was finalized and is currently being field tested in clinic. Scoliosis Choice may help patients and surgeons better understand the potential risks and benefits of spinal fusion vs. observation for scoliosis treatment and improve validated measures of quality in patient-parent-surgeon communication.

Revision risk after pediatric spinal deformity surgery: a nationwide study with 2-year follow-up

BACKGROUND CONTEXT

Revision risk after pediatric spine surgery is not well established and varies between deformity etiologies.

PURPOSE

To report the 2-year revision risk following surgery for primary pediatric spinal deformity in a nationwide cohort and to evaluate potential risk factors and reasons for revision surgery.

DESIGN

Retrospective nationwide cohort study.

PATIENT SAMPLE

A national registry study of all pediatric spinal deformity patients undergoing surgery during 2006-2015 (n=1310).

OUTCOME MEASURES

Two-year revision risk.

METHODS

All patients ≤21 years of age undergoing spinal deformity surgery in Denmark during 2006-2015 were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). Data on revision surgery were retrieved from the DNPR. Patients were categorized in six groups according to etiology. Medical records were reviewed for reason for revision in all patients. Potential risk factors for revision were assessed with multiple logistic regression analyses and included age, etiology, sex, Charlson comorbidity index (CCI), and growth-preserving treatment.

RESULTS

Patients were categorized according to etiology: idiopathic deformity (53%), neuromuscular deformity (23%), congenital/structural deformity (9%), spondylolisthesis (7%), Scheuermann's kyphosis (5%), and syndromic deformity (3%). Of 1,310 included patients, 9.2% underwent revision surgery within 2 years and 1.5% was revised more than once. Median time to revision was 203 (interquartile range 35-485) days. The multivariable logistic regression found significantly higher odds ratio (OR) for revision in patients with growth-preserving treatment (OR=5.1, 95% confidence interval [CI] 2.6-10.1), congenital deformity (OR=2.7, 95% CI 1.3-5.3), spondylolisthesis (OR=3.5, 95% CI 1.9-6.7), Scheuermann kyphosis (OR=3.9, 95% CI 1.9-8.3), and CCI score ≥3 (OR=2.5 95% CI 1.1-5.6). The most common reason for revision was implant failure (32.5%) followed by residual deformity and/or curve progression (15.8%).

CONCLUSIONS

In this nationwide study, the 2-year revision risk after primary pediatric spinal deformity surgery is 9.2%. Risk factors for revision are etiology of congenital deformity, spondylolisthesis, Scheuermann kyphosis as well as patients with growth-preserving treatment and higher CCI. The most common reason for revision is implant failure.

Incidence and risk factors of reoperation in patients with adjacent segment disease: A meta-analysis

Study Design:

This was a systematic review of the literature and meta-analysis.

Objective:

The objective of this study was to evaluate the current literature regarding the risk factors contributing to reoperation due to adjacent segment disease (ASD).

Summary of Background Data:

ASD is a broad term referring to a variety of complications which might require reoperation. Revision spine surgery is known to be associated with poor clinical outcomes and high rate of complications. Unplanned reoperation has been suggested as a quality marker for the hospitals.

Materials and Methods:

An electronic search was conducted using PubMed. A total of 2467 articles were reviewed. Of these, 55 studies met our inclusion criteria and included an aggregate of 1940 patients. Data were collected pertaining to risk factors including age, sex, fusion length, lumbar lordosis, body mass index, pelvic incidence, sacral slope, pelvis tilt, initial pathology, type of fusion procedure, floating versus sacral or pelvic fusion, presence of preoperative facet or disc degeneration at the junctional segment, and sagittal orientation of the facets at the junctional segment. Analysis of the data was performed using Comprehensive Meta-Analysis software (Biostat, Inc.).

Results:

The overall pooled incidence rate of reoperation due to ASD from all included studies was 0.08 (confidence interval: 0.065–0.098). Meta-regression analysis demonstrated no significant interaction between age and reoperation rate (P = 0.48). A comparison of the event rates between males and females demonstrated no significant difference between male and female reoperation rates (P = 0.58). There was a significantly higher rate of ASD in patients with longer fusion constructs (P = 0.0001).

Conclusions:

We found that 8% of patients in our included studies required reoperation due to ASD. Our analysis also revealed that longer fusion constructs correlated with a higher rate of subsequent revision surgery. Therefore, the surgeon should limit the number of fusion levels if possible to reduce the risk of future reoperation due to ASD.

Level of evidence:

IV

Secondary Surgery Rates After Primary Fusion for Adolescent Idiopathic Scoliosis

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

Minimum 20-Year Health-Related Quality of Life and Surgical Rates After the Treatment of Adolescent Idiopathic Scoliosis

STUDY DESIGN

Longitudinal cohort.

OBJECTIVES

To determine the patient-reported functional outcomes and need for related surgical procedures in a US cohort of adolescent idiopathic scoliosis (AIS) patients with minimum 20-year follow-up.

SUMMARY OF BACKGROUND DATA

There is limited information regarding the long-term outcomes of scoliosis treatment in the US population.

METHODS

A novel population of patients who underwent pediatric treatment for AIS with minimum 20-year follow-up was identified. Search of a single-center diagnostic registry generated 337 patients who fulfilled the inclusion criteria (AIS, curve magnitude >35°, and childhood treatment with bracing, surgery, or observation from 1975 to 1992). Any additional spine surgery as well as EQ5D, ODI, SRS 22, SAQ were determined. A total of 180 patients were included (mean of 30-year follow-up, range 20-37). Childhood treatment entailed bracing (41 patients), surgery (103 patients), and observation (36 patients).

RESULTS

During the study period, only 1 of the 41 bracing patients underwent additional scoliosis-related spine surgery, whereas 5 of the 36 patients in the observation cohort underwent scoliosis surgery as adults. Seven of 103 childhood surgical patients required additional revision surgery as adults. Fifteen patients (4 braced, 7 fusion, and 4 observed) underwent chest wall surgery as adults. SRS scores were around 10% worse compared to population-based controls, with the exception of SRS mental health scores, which were similar to controls. Overall, 5.6% of patients were on disability, with no difference between operative and nonoperative groups.

CONCLUSION

We found a low rate of adult scoliosis surgery in the braced population, and a low rate of revision surgery at the 30-year follow-up in patients undergoing spine fusion for AIS between 1975 and 1992. No detected differences in patient-reported outcomes were found between the braced, surgical, and observed populations at a mean of 30 years' follow-up.

LEVEL OF EVIDENCE

Level III, therapeutic.

Cost-Utility Analysis of Operative Versus Nonoperative Treatment of Thoracic Adolescent Idiopathic Scoliosis

STUDY DESIGN

Cost-utility analysis OBJECTIVE.: To compare the cost utility of operative versus nonoperative treatment of adolescent idiopathic scoliosis (AIS) and identity factors that influence cost-utility estimates.

SUMMARY OF BACKGROUND DATA

AIS affects 1% to 3% of children aged 10 to 16 years. When the major coronal curve reaches 50°, operative treatment may be considered. The cost utility of operative treatment of AIS is unknown.

METHODS

A decision-analysis model comparing operative versus nonoperative treatment was developed for a hypothetical 15-year-old skeletally mature girl with a 55° right thoracic (Lenke 1) curve. The AIS literature was reviewed to estimate the probability, health utility, and quality-adjusted life years (QALYs) for each event. For the conservative model, we assumed that operative treatment did not result directly in any QALYs gained, and the health utility in AIS patients was the same as the age-matched US population mean. Costs were inflation-adjusted at 3.22% per year to 2015 US dollars. Costs and benefits were discounted at 3%. Probabilistic sensitivity analysis was performed using mixed first-order and second-order Monte Carlo simulations. Incremental cost utility ratio (ICUR) and incremental net monetary benefit were calculated. One-way sensitivity analyses were performed by varying cost, probability, and QALY estimates.

RESULTS

Operative treatment was favored in 98.5% of simulations, with a median ICUR of $20,600/QALY (95% confidence interval, $20,500-$21,900) below the societal willingness-to-pay threshold (WTPT) of $50,000/QALY. The median incremental net monetary benefit associated with operative treatment was $15,100 (95% confidence interval, $14,800-$15,700). Operative treatment produced net monetary benefit across various WTPTs. Factors that most affected the ICUR were net costs associated with uncomplicated operative treatment, undergoing surgery during adulthood, and development of pulmonary complications.

CONCLUSION

Cost-utility analysis suggests that operative treatment of AIS is favored over nonoperative treatment and falls below the $50,000/QALY WTPT for patients with Lenke 1 curves.

LEVEL OF EVIDENCE

2.

Gait in patients with adolescent idiopathic scoliosis. Effect of surgery at 10 years of follow-up

PURPOSE

To assess radiological and gait biomechanical changes before, at one and 10 years after surgery in AIS patients.

METHODS

This clinical prospective study included fifteen adult women (mean[SD] age: 26 [1] years) diagnosed with thoraco-lumbar/lumbar AIS and operated 10 years ago. Clinical, radiological and gait variables, including kinematics, electromyography (EMG), mechanics and energetics were compared between presurgery (S0), 1 year (S1) and 10 years (S2) postsurgery period using a one way repeated measure ANOVA.

RESULTS

The Cobb angle of the scoliosis curve was reduced by 55% at 1 year postsugery but only by 37% at 10 years postsurgery suggesting a loss of 32% over time. Frontal plumb line C7-S1 distance was significantly improved by surgery (-44%) and remained stable at 10 years postsurgery. Lower limb kinematics was not affected by the surgery at long term. Excessive bilateral activation of lombo-pelvic muscles, observed before surgery, decreased significantly at S1 and S2 period. Mechanical energy increased significantly between S0, S1 and S2 session, without any change for the energetic variables.

CONCLUSIONS

Between 1 and 10 years post-surgery, thoraco-lumbar/lumbar AIS women showed a few decompensation of the curve without any change of the improved frontal body balance. Lower limbs and pelvic motion, during gait, was not affected by the surgery. But presurgical excessive EMG activity of the lumbo-pelvic muscle and reduced mechanical energy produced to walk get similar to normal patterns. Only the oxygen consumption remained excessive probably due to physical deconditioning or postural instability.

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

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

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

STUDY DESIGN

Multicenter retrospective review.

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Level IV.

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

STUDY DESIGN

An actuarial "survivorship" analysis.

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

3.

Primary Versus Revision Spinal Fusion in Children: An Analysis of 74,525 Cases From the Nationwide Inpatient Sample

STUDY DESIGN

Retrospective cohort study of a nationwide database.

OBJECTIVE

To compare in-hospital outcomes for pediatric patients who underwent primary versus revision spinal fusion.

SUMMARY OF BACKGROUND DATA

There is limited data on outcomes after primary versus revision spinal fusion in children.

METHODS

Data from the Nationwide Inpatient Sample from 2002 to 2011 were analyzed. Pediatric patients (age <18 yr) who underwent ≥3 level spinal fusion were identified. Demographics, in-hospital complications, length of stay, and hospital charges were compared between primary and revision (refusion) procedures. All analyses were performed after application of discharge weights.

RESULTS

Data from 72,483 primary fusion and 2042 revision fusion procedures (2.7%) were analyzed. Average length of stay was 7.9 days for the revision group and 6.6 for the primary group (P = 0.022). Average total charges were $135,644 and $142,029 for the revision and primary fusion groups, respectively (P = 0.252). The percentage of patients who developed at least one in-hospital complication was 16.7% in the revision group and 8.6% in the primary fusion group (P < 0.001). Specific complications that were more common in the revision group were reintubation (4.3% vs. 2.3%, P = 0.008), hemorrhage/hematoma (5.0% vs. 2.5%, P = 0.001), wound complications (4.0% vs. 1.1%, P < 0.001), accidental vessel/nerve puncture (2.6% vs. 0.8%, P < 0.001), implant-related complications (5.3% vs. 0.4%, P < 0.001), and incidental durotomy (2.1% vs. 0.3%, P < 0.001). On multivariate analysis, revision procedures (odds ratio [OR] 2.64; 95% confidence interval [CI] 1.93-3.59; P < 0.001), male sex (OR 1.73; 95% CI 1.52-1.98; P < 0.001), and fusion of eight or more spinal levels (OR 1.27; 95% CI 1.09-1.47; P = 0.001) were risk factors for complication development.

CONCLUSION

In the present study, pediatric patients who underwent spinal refusion had significantly higher complication rates compared to patients who underwent primary fusion, consistent with previous investigations. Male patients and patients who underwent fusion of eight or more spinal levels also had higher complication rates.

LEVEL OF EVIDENCE

3.

Risk of revision surgery for adult idiopathic scoliosis: a survival analysis of 517 cases over 25 years

PURPOSE

Little is known about the long-term status of patients operated for spine deformities. The aim of this study was to determine the survival of primary fusion in adult idiopathic scoliosis and identify the risk factors of revision surgery.

METHODS

Adult patients who underwent primary fusion for idiopathic scoliosis between 1983 and 2011 were included in a continuous monocentric retrospective series. Any additional surgery was registered for survival analysis. Survival and follow-up were estimated by the Kaplan-Meier method and an analysis was performed to identify the risk factors of revision surgery.

RESULTS

This series included 447 women (86.5 %) and 70 men (13.5 %) reviewed after a mean follow-up of 7 years (range 0-26.4). Mean age was 44.4 years. Fusion was performed on a median 11 levels (range 3-15); revision rate was 13 % (CI 10-17), 18 % (CI 14-23) and 20 % (CI 16-26) at 5, 10 and 15 years, respectively. Revision surgery was associated with age, anterior release, length of fusion, the inferior limit of fusion, post-operative sagittal balance and junctional kyphosis. The length of fusion (HR 1.13 per vertebrae fused, p = 0.007) and the lower limit of fusion (HR 5.9, p < 0.001) remained independent predictors of revision surgery on multivariate analysis.

CONCLUSION

This series evaluated the risk of revision surgery following spinal fusion for idiopathic scoliosis. Our results show that the risk seemed to increase linearly with a rate of nearly 20 % after 10 years. The length and lower limit of fusion are the main risk factors for revision surgery. Level IV (e.g. case series).

Role of Intraoperative Radiographs in the Surgical Treatment of Adolescent Idiopathic Scoliosis

BACKGROUND

One of the main goals of scoliosis surgery is to obtain a balanced fused spine. Although preoperative planning remains essential, intraoperative posteroanterior radiographs are the only available tool during the procedure to verify shoulder and coronal spinal balance and, if necessary, adjust the construct. The aim of this study was to quantify the direct influence of intraoperative radiographs on the surgical procedure itself during correction of adolescent idiopathic scoliosis.

METHODS

Retrospective analysis of prospectively collected data on a monocentric cohort of adolescent idiopathic scoliosis patients undergoing corrective surgery. A total 148 consecutive patients operated in the same department following the same validated preoperative planning method were included in this prospective radiologic study. The mean follow-up averaged 33 months. Frontal Cobb angles, T1 tilt, shoulder tilt, iliolumbar angle, and frontal balance were measured and compared on intraoperative, early postoperative, and latest follow-up radiographs. Any intraoperative modification of the correction performed after analysis of the intraoperative radiograph were recorded.

RESULTS

The analysis of all radiologic parameters was possible in 90.5% of the cases. In 9.5% of the cases, shoulders could not be properly distinguished. Significant modifications on the upper thoracic curve to correct T1 tilt or shoulder balance were performed in 29% of the patients, and changes at the distal levels were recorded in 19%, underlining planification imperfections. On postoperative standing radiographs, the average coronal parameters were neutral, without loss of correction at follow-up.

CONCLUSIONS

Intraoperative radiographs remain necessary to ensure compensation of the shortcomings of the modern preoperative planification method.

Causes of the failure and the revision methods for congenital scoliosis due to hemivertebra

The purpose of this study was to retrospectively investigate the causes of failure in the first operation and the revision procedure for patients with congenital scoliosis due to hemivertebra. Nineteen patients who underwent the revision operations because of failure in the first operation were included in this study. All the malformations were identified as fully segmented hemivertebra, including 16 cases in thoracolumbar vertebra (T10: three patients; T12: seven patients; L1: six patients), and three cases in thoracic vertebra (T8). The causes of failure in the first operation and the outcome of revision procedure for patients were retrospectively analyzed. All patients were successfully performed the personalized revision surgeries. The failure reasons of the first operation included limitations of the first operation procedure, no or incomplete resection of the malformed hemivertebra, improper operation during surgery, improper internal fixation material, and improper internal fixation scope. The average postoperative scoliosis Cobb's angle and kyphosis Cobb's angle were corrected from 54.1° preoperatively to 23.1° postoperatively, and 59.3° preoperatively to 25.8° postoperatively, respectively. The average postoperative distance between the C7 plumb line and the center sacral vertical line was decreased from 2.5 cm preoperatively to 1.5 cm postoperatively. The average follow-up period was 2.2 years. No serious complication was observed. The cause of the failure of the first operations for the congenital scoliosis due to hemivertebra is verified. Our study may provide a basis for the treatment of congenital scoliosis due to hemivertebra.

Revision surgery for pediatric spine deformity: corrective osteotomies

BACKGROUND

Revision spinal deformity surgery is a considerable undertaking and should never be taken lightly. The complication rates are typically higher than index surgery and technical difficulties are of greater magnitude.

METHODS

A review of the literature on revision surgery on pediatric spine deformities is provided with technical details of vertebral column resection.

CONCLUSIONS

Careful planning and preparation as well as previous experience with such deformities are of utmost importance to achieve satisfactory results.

Unanticipated revision surgery in adult spinal deformity: an experience with 815 cases at one institution

STUDY DESIGN

Retrospective case series.

OBJECTIVE

This study reviewed the overall prevalence and indications of revision surgical procedures for adult scoliosis in a single institution. In this largest single-institution series, revision surgery in adult scoliosis was required for a relatively low proportion of cases (7.61%). The main indications were implant breakage, deformity progression, and infection.

SUMMARY OF BACKGROUND DATA

Spine fusion is considered as the final therapeutic intervention in the management of adult scoliosis. However, reports on the repeat surgical intervention of adult scoliosis predate the use of advanced instrumentation systems.

METHODS

The scoliosis database of our center was searched, and all cases with index spinal fusion surgical procedures performed for adult scoliosis from 1998 to 2011 with the follow-up period of more than 2 years were identified. The clinical data and radiographs of patients were reviewed to provide information on the indication of initial operation and any subsequent revision surgery. A total of 815 patients were identified, with a mean age of 30.49 years (range, 20-76 yr). The mean follow-up periods were 6.4 years (range, 2-15 yr) for the entire cohort and 7.6 years (range, 2.5-12 yr) for the subset of the cohort requiring revision.

RESULTS

The patients exhibiting multiple reasons for revision were classified under primary reason and subjected to subsequent analysis. Among the 815 patients, 62 (7.61%) underwent at least 1 revision surgery. The most common reasons for revision were implant breakage (23/62; 37.1%), deformity progression (10/62; 16.1%), and infection (9/62; 14.5%). The other indications were pseudarthrosis (n = 8), implant dislodgement (n = 6), junctional kyphosis (n = 5), and neurological deficit (n = 1). Revision rate was significantly higher in patients older than 40 years (15.23% vs. 5.87%), in patients with degenerative or congenital scoliosis (15.12% vs. 12.82%), or in patients with hybrid constructs (12.12% vs. 5.82%).

CONCLUSION

In this largest single-institution series, revision surgery after index spinal fusion in patients with adult scoliosis was required for a relatively low proportion of surgical cases (7.61%). The main indications for revision were implant breakage, deformity progression, and infection.

Utility of Postoperative Radiographs for Pediatric Scoliosis: Association Between History and Physical Examination Findings and Radiographic Findings

BACKGROUND

Postoperative radiographs are routinely obtained following surgery for the correction of scoliosis in pediatric patients. The purpose of this study was to comprehensively evaluate the utility of obtaining routine postoperative radiographs in the management of these patients.

METHODS

A total of 1969 clinic notes and corresponding radiographs regarding 451 consecutive patients with scoliosis (age range, ten to eighteen years) who had surgical correction over a ten-year period at a single institution were retrospectively reviewed. Curve etiology, preoperative curve characteristics, and surgical procedures performed were recorded. All postoperative clinic notes and radiographs were reviewed for abnormalities and changes in treatment course. It was then determined whether clinical signs and symptoms and/or abnormal radiographic findings led to a change in treatment course, which was defined as a therapeutic intervention or further diagnostic testing.

RESULTS

Of the 451 patients in this study (average age [and standard deviation], 14.7 ± 2.4 years), 72.5% had adolescent idiopathic scoliosis, 23.3% had neuromuscular scoliosis, and 4.2% had other underlying causes of scoliosis. A change in treatment course occurred in the cases of forty-two patients, all of whom had symptomatic findings on postoperative history and physical examination and only fifteen of whom had supportive abnormal findings on postoperative radiographs. Curve etiology and surgical procedures performed had no impact on radiographic utility. A significant increase in utility was seen for radiographs obtained at visits one year or more following surgery compared with those obtained at visits less than one year following surgery (1.7% compared with 0.3%, p = 0.001). The overall sensitivity, specificity, positive predictive value, and negative predictive value of routine postoperative radiographs in guiding treatment course were 35.7%, 98.1%, 28.8%, and 98.6%, respectively.

CONCLUSIONS

Routine radiographs provide low utility in guiding the course of treatment for asymptomatic pediatric patients following surgery for scoliosis. The results of this study suggest that patient or caregiver complaints, comorbidities, and clinical suspicion should be considered before obtaining radiographs at postoperative visits in order to minimize radiation exposure in pediatric patients and reduce medical costs without compromising care.

LEVEL OF EVIDENCE

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

Unplanned reoperation within 30 days of fusion surgery for spinal deformity

No recent studies have analyzed the rates of or reasons for unanticipated revision surgery within 30 days of primary surgery in spinal deformity patients. Our aim was to examine the incidence, characteristics, reasons, and risk factors for unplanned revision surgery in spinal deformity patients treated at one institution. All patients with a diagnosis of spinal deformity presenting for primary instrumented spinal fusion at a single institution from 1998 to 2012 were reviewed. All unplanned reoperations performed within 30 days after primary surgery were analyzed in terms of demographics, surgical data, and complications. Statistical analyses were performed to obtain correlations and risk factors for anticipated revision. Of 2758 patients [aged 16.07 years (range, 2–71), 69.8% female] who underwent spinal fusion surgery, 59 (2.1%) required reoperation within 30 days after primary surgery. The length of follow up for each patient was more than 30 days. Of those that required reoperation, 87.0% had posterior surgery only, 5.7% had anterior surgery, and 7.3% underwent an anteroposterior approach. The reasons for reoperation included implant failure (n = 20), wound infection (n = 12), neurologic deficit (n = 9), pulmonary complications (n = 17), and coronal plane imbalance (n = 1). The risk factors for reoperation were age, diagnosis, and surgical procedure with osteotomy.

Unplanned return to the operating room in patients with adolescent idiopathic scoliosis: are we doing better with pedicle screws?

STUDY DESIGN

Prospective, longitudinal cohort.

OBJECTIVE

To evaluate the incidence, timing, and risk factors for reoperation in patients with adolescent idiopathic scoliosis (AIS) treated with pedicle screws (PSs) compared with hybrid (Hb) constructs.

SUMMARY OF BACKGROUND DATA

Rates of return to the operating room (OR) after definitive fusion for AIS vary, with a paucity of data on PS constructs.

METHODS

A prospective multicenter database was retrospectively queried to identify consecutive patients with AIS who underwent posterior spinal fusion with either PS or Hb constructs with a minimum 2-year follow-up. All reoperations were stratified into an early group (<60 d) or a late group (>60 d). Univariate and multivariate logistical analyses were performed to identify potential risk factors related to reoperation.

RESULTS

A total of 627 patients met the inclusion criteria (PS = 540, Hb = 87). There was a statistically significant difference in the rate of reoperations between the PS (3.5%) and Hb groups (12.6%), P < 0.001. Early return to the OR occurred in 2.0% of the patients with PS compared with 3.4% in the Hb group, P = 0.43. Late returns to the OR occurred in 1.5% of PS group versus 9.2% of the Hb group, P < 0.001. Multivariate analysis revealed longer operating time as an independent risk factor for an unplanned return to the OR in patients treated with PSs (P < 0.05).

CONCLUSION

Our results suggest that patients with AIS treated with PS have decreased rates of unplanned return to the OR when compared with patients with Hb constructs. The majority of returns to the OR were early (<60 d) for the PS group compared with late (>60 d) for the Hb group. Longer operative times increased the risk of unplanned reoperation for the PS group.

LEVEL OF EVIDENCE

3.

Complications of surgical treatment of pediatric spinal deformities

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

Late Proximal Pedicle Hook Migration Into Spinal Canal After Posterior Correction Surgery of Scoliosis Causing Neurologic Deficit: "Proximal Junctional Scoliosis"? Case Series and a Review of the Literature

STUDY DESIGN

Case series.

OBJECTIVES

We describe 4 patients with proximal pedicle hook migration as a late complication (greater than 12 months postoperatively) of posterior correction surgery in adolescent idiopathic scoliosis. We studied failure mechanisms and propose strategies for revision surgery.

SUMMARY OF BACKGROUND DATA

Few published cases of hook migration into the spinal canal concern mainly intra-operative or early postoperative dislodgement. Re-operation rates for adolescent idiopathic scoliosis are 2% to 10%.

METHODS

We retrospectively reviewed medical records and radiographic images in 4 patients with symptomatic pedicle hook migration into the spinal canal. We studied our scoliosis revision surgery rates over the past 10 years and reviewed the literature for instrumentation failure after scoliosis surgery.

RESULTS

Our total re-operation rate between January 2002 and April 2012 was 7.0% (56 of 800 procedures), with a mean follow-up of 61 months (range, 6-129 months). Proximal hook migration presented in 1.0% (8 of 800 procedures), including 4 into the spinal canal. These 4 patients presented with pain symptoms 19-78 months after uneventful index posterior correction surgery. In all 4 patients, radiographic imaging showed proximal pedicle hook migration into the spinal canal without proximal sagittal alignment problems. In all patients, spinal fusion was observed on computed tomographic imaging and at revision surgery. Revision surgery consisted of at least hook removal. In all 4 patients, symptoms completely resolved over time.

CONCLUSIONS

Hooks can migrate and potentially cause neurologic impairment and pain long after index surgery, despite the presence of solid spinal fusion. We believe this is partly the result of the surgical technique we used and have since abandoned, and partly the proximal spine settling and fusion mass deformation over time, which we call "proximal junctional scoliosis." We recommend computed tomographic imaging in case of postoperative symptoms and removal of hooks in case of hook migration into the spinal canal.