Comparison of segmental pedicle screw instrumentation versus anterior instrumentation in adolescent idiopathic thoracolumbar and lumbar scoliosis

Proximal junctional kyphosis in Lenke 5C adolescent idiopathic scoliosis after selective posterior thoracolumbar/lumbar fusion: risk factors and predictive index

BACKGROUND

Although several studies have reported that selective posterior thoracolumbar/lumbar (TL/L) fusion can yield satisfactory results in Lenke 5C adolescent idiopathic scoliosis (AIS), the proximal junctional kyphosis (PJK) is still a common complication that occurs after surgery. The purpose of this study is to analyse the risk factors for postoperative proximal junctional kyphosis in Lenke 5C patients who underwent selective posterior TL/L fusion and explore whether PJK can be predicted.

METHODS

A total of 83 AIS patients with Lenke 5C curves who met the inclusion criteria were analysed. All patients were divided into two groups based on the occurrence of postoperative PJK. Univariate and multivariate analyses were used to identify independent factors significantly associated with PJK, and an PJK index was proposed and verified.

RESULTS

PJK was observed in 27 of 83 (32.5%) patients in the study. Preoperative thoracic kyphosis (TK) and the immediate postoperative proximal junctional angle (PJA) were the primary factors identified by the binary logistic regression analysis. The PJK index was defined as 1.1× preoperative TK + 2.3× immediate postoperative PJA. The receiver operating characteristics curve indicated that the occurrence rate of PJK was 85% and non-occurrence rate was 82% when the PJK index was greater than 42.

CONCLUSION

Large preoperative TK and a large immediate postoperative PJA play important roles in the development of PJK in Lenke 5C patients treated with selective posterior thoracolumbar/lumbar fusion. The PJK index can be used to predict the occurrence of PJK with high accuracy. To prevent the occurrence of PJK, we should pay attention to the TLK, and preserving more posterior proximal intervertebral elements at the upper instrumented vertebral level would be an important part of corrective surgery; however, moderate correction of the lumbar curve is recommended.

Cement Augmentation of Pedicle Screw Instrumentation: A Literature Review

This literature review aimed to review the current understanding, indications, and limitations of pedicle screw instrumentation cement augmentation. Since they were first reported in the 1980s, pedicle screw cement augmentation rates have been increasing. Several studies have been published to date that describe various surgical techniques and the biomechanical changes that occur when cement is introduced through the screw-bone interface. This article provides a concise review of the uses, biomechanical properties, cost analysis, complications, and surgical techniques used for pedicle screw cement augmentation to help guide physician practices. A comprehensive review of the current literature was conducted, with key studies, and contributions from throughout history being highlighted. Patients with low bone mineral density are the most well-studied indication for pedicle screw cement augmentation. Many studies show that cement augmentation can improve pullout strength in patients with low bone mineral density; however, the benefit varies inversely with pathology severity and directly with technique. The various screw types are discussed, with each having its own mechanical advantages. Cement distribution is largely dependent on the filling method and volume of cement used. Cement composition and timing of cement use after mixing are critical considerations in practice because they can significantly alter the bone-cement and screw-cement interfaces. Overall, studies have shown that pedicle screw cement augmentation has a low complication rate and increased pullout strength, justifying its universal use in patients with a suboptimal bone-implant interface.

Proximal junctional kyphosis in pediatric spinal deformity surgery: a systematic review and critical analysis

PURPOSE

Proximal junctional kyphosis (PJK) is a commonly encountered clinical and radiographic phenomenon after pediatric and adolescent spinal deformity surgery that may lead to post-operative deformity, pain, and dissatisfaction. Understanding the risk factors of PJK can be useful for pre-operative informed consent as well as to identify any potential preventative strategies.

METHODS

We performed a systematic review and critical analysis following the PRISMA statement in July 2019 by searching the PubMed, Scopus, and Embase databases, including all prior published studies. We included articles with data on PJK in patients with operative pediatric and adolescent scoliosis and those that detailed risk factors and/or preventative strategies for PJK. Levels of evidence were determined based on consensus. Findings were summarized and grades of recommendation were assigned by consensus. This study was registered in the PROSPERO database; 202,457.

RESULTS

Six hundred and thirty five studies were identified. Thirty-seven studies met criteria for inclusion into the analysis. No studies including neuromuscular scoliosis met inclusion criteria. No findings had Grade A evidence. There were 4 findings found to contribute to PJK with Grade B evidence in EOS: higher number of distractions, disruption of posterior elements, greater sagittal plane correction. There was no difference in incidence noted between etiology of the curvature. Five findings with Grade B evidence were found to contribute to PJK in AIS populations: higher pre-operative thoracic kyphosis, higher pre-operative lumbar lordosis, longer fusion constructs, greater sagittal plane correction, and posterior versus anterior fusion constructs.

CONCLUSION

Greater sagittal plane correction has Grade B evidence as a risk factor for PJK in both EOS and AIS populations. In EOS patients, an increased number of distractions and posterior element disruption are Grade B risk factors. In AIS patients, longer fusion constructs, higher pre-operative thoracic kyphosis and lumbar lordosis, and posterior (as opposed to anterior) constructs also contributed to PJK with Grade B evidence. These findings can guide informed consent and surgical management, and provide the foundation for future studies.

The Biomechanical Properties of Cement-Augmented Pedicle Screws for Osteoporotic Spines

STUDY DESIGN

This is a broad, narrative review of the literature.

OBJECTIVE

In this review, we describe recent biomechanics studies on cement-augmented pedicle screws for osteoporotic spines to determine which factors influence the effect of cement augmentation.

METHODS

A search of Medline was performed, combining the search terms "pedicle screw" and ("augmentation" OR "cement"). Articles published in the past 5 years dealing with biomechanical testing were included.

RESULTS

Several factors have been identified to impact the effect of cement augmentation in osteoporotic spines. These include the type of augmentation material, the volume of injected cement, the timing of augmentation, the severity of osteoporosis, the design of the pedicle screw, and the specific augmenting technique, among others.

CONCLUSIONS

This review elaborates the biomechanics of cement-augmented pedicle screws, determines which factors influence the augmentation effect, and identifies the risk factors of cement leakage in osteoporotic bone, which might offer some guidance when using this technique in clinical practice. Further, we provide information about newly designed screws and recently developed augmentation materials that provide higher screw stability as well as fewer cement-related complications.

Anterior versus posterior spinal fusion for Lenke type 5 adolescent idiopathic scoliosis: a systematic review and meta-analysis of comparative studies

PURPOSE

To review and compare clinical and radiologic outcomes between anterior spinal fusion (ASF) and posterior spinal fusion (PSF) for the treatment of Lenke type 5 adolescent idiopathic scoliosis (AIS).

METHODS

A systematic review was performed according to Preferred reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. All level I-III evidence studies investigating the clinical and radiologic outcomes of ASF and PSF for the treatment of Lenke type 5 AIS were included.

RESULTS

Nine studies (285 ASF patients, 298 PSF patients) were included. ASF was associated with a significantly lower number of levels fused compared with PSF (p < 0.01) with similar immediate and long-term coronal deformity correction (p = 0.16; p = 0.12, respectively). PSF achieved a better correction of thoracic hypokyphosis in one study and lumbar hypolordosis in three studies. PSF was associated with a significant shorter length of stay (LOS) compared with ASF (p < 0.01). One long-term study demonstrated a significantly higher rate of proximal junctional kyphosis (PJK) with PSF compared with ASF. There were no significant differences in major complication or re-operation rates.

CONCLUSION

For the treatment of Lenke type 5 AIS, there is moderate evidence to suggest that ASF requires a lower number of instrumented levels to achieve similar immediate and long-term coronal deformity correction compared with PSF. There is some evidence to suggest that PSF may achieve better thoracic and lumbar sagittal deformity correction compared with ASF. There is some evidence to suggest a higher incidence of PJK at long-term follow-up with PSF compared with ASF. ASF is associated with a longer post-operative LOS compared with PSF.

Anterior Selective Lumbar Fusion Saving More Distal Fusion Segments Compared with Posterior Approach in the Treatment of Adolescent Idiopathic Scoliosis with Lenke Type 5: A Cohort Study with More Than 8-Year Follow-up

Objective

To investigate whether anterior selective fusion (ASF) could save more distal fusion segments compared with posterior approach in the treatment of Lenke type 5 adolescent idiopathic scoliosis with long term follow‐up.

Methods

A retrospective cohort study. From 2008 to 2011, 22 AIS girls with Lenke type 5 who underwent ASF or posterior selective fusion (PSF) with more than 8‐year follow‐up, were extracted from the database. 13 girls in the ASF group had an average age of 14.3 ± 1.3 years and Risser sign of 3.3 ± 1.1; 9 PSF girls had an average age of 16.2 ± 3.6 years and Risser sign of 3.8 ± 1.5. The radiographic outcome was compared between groups preoperatively, 6‐month postoperatively, 8‐year postoperatively and at last follow‐up (>8 years).

Results

The average follow‐up duration was 8.7 ± 0.4 (ASF) and 8.8 ± 0.5 (PSF) years, respectively. There was no significant difference at baseline in age, Risser sign and preoperative curve pattern in the coronal and sagittal plane between the groups (P > 0.05). The ASF group had significantly shorter fusion segments (5.1 ± 0.6 vs. 7.0 ± 1.3) and decreased upper instrumented vertebra (UIV) (T₁₁ ± 0.8 vs. T₁₀ ± 0.8) than the PSF (P < 0.05); while no significant difference was found in the lower instrumented vertebra (LIV) and distal reserved segments (P > 0.05), which suggested that ASF could shorten the fusion segments by lowering UIV. The distal compensatory curve in the ASF group (9.0° ± 3.9°) was significantly larger than in the PSF group (3.3° ± 2.4°, P = 0.003), despite of no significant difference in the incidence of coronal imbalance (P > 0.05), indicating that both two approaches could obtain satisfactory correction in the coronal plane. In the sagittal plane, PSF patients had significantly larger lumbar lordosis (LL, 59.1° ± 10.5°), thoracic kyphosis (TK, 37.2° ± 13.3°) and proximal junctional angle (PJA, 13.3° ± 6.1°) at the last follow‐up than the ASF (LL: 43.4° ± 9.4°; TK: 20.7° ± 8.4°; PJA: 4.7° ± 3.4°; P < 0.05), but without significant difference in proximal junctional kyphosis (PJK) and sagittal vertical axis (SVA) (P > 0.05). After controlling for age, Risser sign, and radiographic parameters related to the primary curve pattern, shorter fusion segments and more distal reserved segments still remained significant in the ASF group with greater Risser sign (P < 0.05). No major intra‐ or post‐operative complications occurred.

Conclusions

Both ASF and PSF could obtain satisfactory coronal and sagittal correction for Lenke 5 AIS; compared with PSF, ASF could shorten the fusion segments by lowering UIV, and save more distal fusion segments only in patients with greater skeletal maturity.

Performance of Forward Roll Maneuvers Following Corrective Spinal Fusion for Idiopathic Scoliosis Patients

BACKGROUND

Fusion surgeries for scoliosis patients are believed to deteriorate sports performance; in particular, forward roll should deteriorate, but no literature is available to substantiate this claim.

HYPOTHESIS

The extent of postoperative deterioration can vary according to surgery type or curve type.

PATIENTS AND METHODS

Idiopathic scoliosis patients between 10 and 29 years of age who underwent correction and fusion surgeries at our hospital were included in this study. Forward roll was recorded on video preoperatively and 1-year postoperatively. Performances were evaluated twice on a 10-point scale by two blinded examiners. Preoperative and 1-year postoperative upright spinal radiographs were analyzed for the Lenke classification, number of fused vertebrae, upper and lower instrumented vertebrae, major curve Cobb angle, thoracic kyphosis, lumbar lordosis, and surgical procedures.

RESULTS

The average age was 16 years. Curve types according to the Lenke classification were: 15, type 1; 5, type 2; 14, type 5; 2, type 6. The mean number of fused vertebrae was 6.9 (3.2 for anterior surgeries and 9.3 for posterior surgeries). The mean preoperative assessment of forward roll was 9.6 points, and the 1-year postoperative assessment was lower at 8.8 points. Cluster analysis classified patients into 3 groups: long fusion with marked performance deterioration (C1), long fusion with minimal deterioration (C2), and short fusion with minimal deterioration (C3). The upper and lower instrumented vertebrae in C1 were more distal than those in C2.

CONCLUSION

Patients with thoracic curves were classified into two groups, and patients who underwent surgeries with more distal upper and lower instrumented vertebra levels exhibited lower postoperative performance. However, patients with Lenke 5 curves who underwent anterior surgery showed better preoperative performance than other patients who underwent posterior surgery, showing minimal postoperative deterioration.

LEVEL OF EVIDENCE

III;Therapeutic Study.

Perioperative outcome and complications following single-staged Posterior Spinal Fusion (PSF) using pedicle screw instrumentation in Adolescent Idiopathic Scoliosis (AIS): a review of 1057 cases from a single centre

Background

There has been a growing interest in using all pedicle screw construct in posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) surgery in recent years. However, studies focusing on perioperative outcome and complications utilizing only pedicle screw system in AIS population are lacking. This study aims to evaluate perioperative outcomes and to determine the prevalence of major and minor complications following single-staged PSF for AIS.

Methods

In this retrospective study of prospectively collected data, 1057 AIS patients operated between 2012 and 2019 were included. Main outcome measures were operative time, intraoperative blood loss, allogeneic blood transfusion rate, length of hospital stay after surgery, complication rate, and mean drop of haemoglobin (Hb) level. We documented the number of fusion levels, screw density, and postoperative radiographic parameters.

Results

There were 917 females and 140 males. Majority were Lenke 1 curve type (46.9%). Mean age was 15.6 ± 3.7 years, with mean BMI of 18.6 ± 3.2 kg/m². Mean operative time was 146.8 ± 49.4 min. Average intraoperative blood loss was 952.9 ± 530.4 ml with allogeneic blood transfusion rate of 5%. Mean screw density was 1.27 ± 0.21 screws per fusion level. Average hospital stay after surgery was 3.5 ± 0.9 days. Twenty-four complications were documented: twelve superficial infections (1.14%), five transient neurological deficits (0.47%), two deep infections (0.19%), two superior mesenteric artery syndrome, and one case each (0.09%) for massive intraoperative blood loss, intraoperative seizure, and lung atelectasis.

Conclusion

AIS patients treated with single-staged PSF using pedicle screw construct had a 0.95% rate of major complications and 1.32% rate of minor complications. Rate of neurologic complication was 0.47% while non-neurologic postoperative complications was 1.80% with infection being the leading complication at 1.32%.

What determines immediate postoperative coronal balance and delayed global coronal balance after anterior spinal fusion for Lenke 5C curves?

PURPOSE

To determine the factors associated with 6-week postoperative global coronal balance and delayed global coronal balance at 2-year follow-up after anterior spinal fusion for Lenke 5C curves.

METHODS

A total of 124 consecutive Lenke 5C curves with minimum 2-year follow-up was studied. Radiographic parameters were studied preoperatively, 6 weeks postoperatively, and 2 years postoperatively. Coronal balance was measured by C7-CSVL and trunk shift < 20 mm. The study outcomes were patients with early coronal balance and those who had immediate imbalance but developed delayed balance. Multivariate regression analyses of associated factors were performed with cutoffs determined by receiver operating characteristic curve.

RESULTS

31.5% patients attained global coronal balance immediate postoperatively and 89.4% of the early imbalance cases showed spontaneous coronal balance at 2-year follow-up. Increased preoperative UIV tilt (OR 1.093; p = 0.026; 95% CI: 1.011-1.182) and reduced immediate postoperative RSH difference (OR 0.963; p = 0.015; 95% CI: 0.935-0.993) were associated with immediate postoperative balance. For those with immediate imbalance, larger preoperative major Cobb angle (OR 1.226; p = 0.047; 95% CI: 1.003-1.499), less preoperative C7-CSVL (OR 0.829; p = 0.016; 95% CI: 0.712-0.966), and less immediate postoperative LIV tilt (OR 0.728; p = 0.013; 95% CI: 0.567-0.934) were associated with 2-year coronal balance. There was significant improvement in function (p = 0.006), self-image (p = 0.039) and total score domains (p = 0.014) in immediate imbalance to 2-year balance and imbalance groups.

CONCLUSION

Successful balance is achieved with a parallel fusion mass when performing anterior spinal fusion for Lenke 5C curves. Patients should be reassured that most attain eventual coronal balance despite the early imbalance. Level of evidence Therapeutic III.

Effectiveness and safety of surgical interventions for treating adolescent idiopathic scoliosis: a Bayesian meta-analysis

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is the most common form of spinal deformity in children and adolescents which presents as complex three-dimensional (3D) deformity of the spine and rib cage. This study aimed to estimate the effectiveness and safety of surgical interventions for AIS using Bayesian meta-analysis.

METHODS

The PubMed, EMBASE, and Cochrane Controlled Register of Trials were searched through Oct 1, 2019, without language restrictions. Relevant studies evaluating combined effectiveness and safety of surgical interventions for AIS were included according to eligibility criteria. The primary outcome measures included pulmonary function (change of absolute forced vital capacity and forced expiratory volume in 1 second from pre-operation to post-operation) and incidence of complications. The secondary outcome measure was change of Cobb angle from pre-operation to post-operation. Data was pooled using a random effects model in pairwise meta-analysis. Bayesian meta-analysis combined direct and indirect evidence using a Bayesian framework.

RESULTS

Twenty-eight case-controlled studies with totally 1970 participants were included. This Bayesian meta-analysis combining direct and indirect evidences indicated that posterior fusion with instrumentation without thoracoplasty (PSF) had the highest probability to achieve better pulmonary function and lower complication rate; video assisted anterior fusion with instrumentation without thoracoplasty (VAT) had the highest probability to obtain better Cobb angle correction based on analysis of rank probability.

CONCLUSION

This Bayesian meta-analysis demonstrated that PSF had the highest probability to achieve better post-surgical pulmonary function and lower complication rate, which gives a practical recommendation of PSF as a primary surgical treatment for AIS. The results also support statistics that current surgeries adopted more PSF but less open anterior approach surgery and thoracoplasty. More research work is required to address the effectiveness and safety of VAT for treating AIS more convincingly.

Posterior Correction of Adolescent Idiopathic Scoliosis with High-Density Pedicle Screw-Only Constructs: 5 Years of Follow-Up

PURPOSE

This study aimed to analyze radiological outcomes in patients with adolescent idiopathic scoliosis (AIS) who underwent posterior correction with high-density pedicle screw-only constructs. We hypothesized that high-density pedicle screw-only constructs in AIS would provide a high correction rate and would facilitate the maintenance of the correction or obviate the loss thereof.

MATERIALS AND METHODS

We retrospectively analyzed radiological outcomes over a minimum follow-up period of 5 years in patients with AIS who underwent posterior correction with high-density pedicle screw-only constructs. A total of 124 consecutive patients were included. Demographic data, including age, sex, operated fusion level, numbers of screw, Lenke curve type, Risser stage, and follow-up period were retrospectively collected from electronic medical records and radiological measurements including serial follow-up.

RESULTS

The average number of pedicle screws was 1.96/vertebra. The average curve correction was 48.3% for the proximal thoracic (PT) curve, 83.1% for the main thoracic (MT) curve, and 80.2% for the thoracolumbar/lumbar (TL/L) curve at final follow-up. Use of high-density pedicle screw-only constructs helped achieve excellent correction rates, with no significant loss of correction at final follow-up.

CONCLUSION

We obtained excellent correction rates of 48.3% for PT, 83.1% for MT, and 80.2% for TL/L curves using high-density pedicle screw-only constructs in AIS, with no significant loss of correction at final follow-up.

The Adolescent Idiopathic Scoliosis International Disease Severity Study: Do Operative Curve Magnitude and Complications Vary by Country?

BACKGROUND

The prevalence of adolescent idiopathic scoliosis (AIS) in diverse regions of the world has been studied. Access to care varies widely, and differences in disease severity and operative treatment outcomes are not well understood. This study aimed to determine variation in disease presentation and operative complications for AIS patients from an international cohort.

METHODS

This is a retrospective study carried out at seven surgical centers in the United States (Manhattan and Miami), Ghana, Pakistan, Spain, Egypt, and China. A total of 541 consecutive patients with AIS were evaluated. Preoperative major curve magnitude, operative parameters, and complications were compared among sites using analysis of variance with post hoc tests and Pearson correlation coefficients. Univariate and multivariate forward stepwise binary logistic regressions determined the variables most predictive of complications.

RESULTS

Countries with lowest-access to care (Ghana, Egypt, and Pakistan) displayed larger curves, more levels fused, longer operative time (OT), and greater estimated blood loss (EBL) than the other countries (p ≤ .001). Increasing curve magnitude was correlated with greater levels fused, longer OT, and greater EBL in all groups (p = .01). In the univariate regression analysis, Cobb magnitude, levels fused, EBL, and OT were associated with complication occurrence. Only OT remained significantly associated with complication occurrence after adjusting for Cobb magnitude, levels fused, and site (odds ratio [OR] = 1.005, 95% confidence interval 1.001-1.007, p = .003). Complications were greatest in Pakistan and Ghana (21.7% and 13.5%, respectively) and lowest in Miami (6.5%).

CONCLUSIONS

Larger curve magnitudes in the least-access countries correlated with more levels fused, longer OT, and greater EBL, indicating that increased curve magnitude at surgery could explain the difference in operative morbidity between low- and high-access countries. With OT as the prevailing predictive factor of complications, we suggest that increased curve magnitude leads to longer OTs and more complications. A lack of access to orthopedic care may be the largest contributor to the postponement of treatment.

LEVEL OF EVIDENCE

Level II.

Patient-Reported SRS-24 Outcomes Scores After Surgery for Adolescent Idiopathic Scoliosis Have Improved Since the New Millennium

STUDY DESIGN

Observational.

OBJECTIVE

To examine changes in patient-reported two-year postoperative outcomes via the Scoliosis Research Society (SRS)-24 Outcomes Instrument from 2001 through 2015.

SUMMARY OF BACKGROUND DATA

Techniques for correction of adolescent idiopathic scoliosis (AIS) have evolved over the years, but it is unclear how these changes have impacted patient-reported outcomes.

METHODS

AIS patients with two-year postoperative follow-up from a prospective multicenter registry were divided into three-year groups based on trends in surgical approach and construct type (2010-2014: 52% anterior, 43% posterior hybrids; 2005-2011: 3% anterior, 5% posterior hybrids; 2012-2015: 0% anterior, 0.2% posterior hybrids). Because of the ordinal scale (1-5) and bipolar nature of the response sets for the SRS-24, domain/total scores were categorized as ≤3 (predominantly negative) or 4-5 (predominantly positive). Variables were compared across the three groups.

RESULTS

A total of 1,695 patients were analyzed; 172 (2010-2014), 926 (2005-2011), and 597 (2012-2015). Average age was 14.7 ± 2 years, the average primary curve was 55° ± 13°, and the group was primarily female (82%). There was a decline in the rate of positive scores for preoperative pain and self-image across the three groups (p < .05). There was an increase in the rate of positive scores for two-year postoperative self-image after surgery, function after surgery, and satisfaction (p < .05). Decreases in length of hospital stay, blood loss, surgical time, preoperative kyphosis, and postoperative trunk shift were observed (p < .05). Increases were observed in levels fused, preoperative major coronal curve, preoperative rib prominence, preoperative trunk shift, percentage correction of major curve, kyphosis restoration, and the rate of double/triple curves (p < .05).

CONCLUSION

The percentage of patients with positive postoperative SRS scores has increased in the modern era, providing evidence that newer surgical techniques are resulting in improved outcomes based on the patients' perspectives. Interestingly, recent patients were more afflicted with negative pain and self-image before surgery.

Long-Term Follow-Up of Anterior Spinal Fusion for Thoracolumbar/Lumbar Curves in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective patient series analysis with update of long-term data.

OBJECTIVE

To define the long-term prognosis of the thoracolumbar/lumbar correction after selective anterior spinal fusion (ASF) in adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The ASF is a well-described procedure for the treatment of AIS. The correction reliability over time, the consequences in adjacent spinal levels and patient's quality of life are fundamental for the characterization of AIS treatment.

METHODS

One hundred seven patients were submitted to single-rod ASF for thoracolumbar/lumbar (ThL/L) AIS between 1993 and 2016 in a single-surgeon experience. Seventy five were available for final follow-up evaluation 9 years ±4 (2-23) after surgery. A clinical and sequential radiographic evaluations were performed.

RESULTS

The mean age at surgery was 16 years ± 2.33 (14-20) and 94 (87%) were females. The mean final follow-up of the 75 patients available was 9 years ± 4 (2-23). Sixty-five patients had a Lenke type 5C curve and 10 had a type 6C curve. The mean values of the Scoliosis Research Society 22 (SRS-22) questionnaire in Lenke 5C was 92 ± 9 (71-109) and in Lenke 6C 90.3 ± 9 (75-107). In Lenke 5C group, the mean preoperative ThL Cobb angle was 38.4° ± 9.3 (21-60) and the postoperative was 5.9° ± 4.5 (0-18; P < 0.001) being similar at the final follow-up (P > 0.05). In Lenke 6C group, the mean preoperative ThL Cobb angle was 58.6° ± 13.9 (40-90) and the postoperative ThL Cobb was 22.6° ± 14.5 (5-48, P < 0.001) being similar at the final follow-up (P > 0.05). The mean preoperative Thoracic (Th) Cobb angle was 39° ± 7.6 (30-50), the postoperative was 30.6° ± 10.1 (14-49, P < 0.008) and in the final follow-up was 29.3° ± 10.7 (11-48, P < 0.011).

CONCLUSION

ASF is a safe procedure in the treatment of ThL/L with good long-term results and high rates of satisfaction among patients with AIS Lenke type 5C. The partial correction was frequent in Lenke type 6C despite the absence of progression in the non-instrumented curves.

LEVEL OF EVIDENCE

4.

Biomechanical Analysis of Wide Posterior Releases Compared With Inferior Facetectomy and Discectomy in the Thoracolumbar and Lumbar Spine

STUDY DESIGN

In vitro biomechanical analysis.

OBJECTIVES

Compare the destabilizing effects of anterior discectomy to posterior spinal releases.

SUMMARY OF BACKGROUND DATA

Posterior release and pedicle screw fixation has become the accepted form of treatment for lumbar and thoracolumbar pediatric scoliotic spinal deformity. A biomechanical evaluation of posterior releases with comparison to traditional anterior releases has not been reported in the lumbar spine.

METHODS

Eleven fresh-frozen human thoracolumbar specimens (T9-L5) were tested by a robotic manipulator (Staubli RX90; moment target of 5.0 Nm, force target of 50 N) in axial rotation (AR), plus lateral and anterior translation (LT and AT). Specimens underwent either sequential anterior release (partial and full discectomy) or posterior release (inferior facetectomy and wide posterior release) from T10 to L4. Partial discectomy retained the posterior 50% of disc and posterior longitudinal ligament, whereas full discectomy removed all of the disc and PLL. Wide posterior release included total facetectomy plus ligamentum flavum and spinous process resection.

RESULTS

Inferior facetectomy produced an average increase of 1.5° ± 1.0° (p = .0625), 1.0 ± 0.8 mm (p = .0313), and 0.2 ± 0.3 mm (p = .156) in AR, LT, and AT, respectively. Compared with partial facetectomy, wide posterior release produced an average additional increase of 8.1° ± 4.0° (p = .0312), 2.0 ± 2.2 mm (p = .4062), and 1.1 ± 1.0 mm (p = .0625) in AR, LT, and AT, respectively. Full discectomy produced 201%, 161%, and 153% of the motion relative to wide posterior release in AR, LT, and AT, respectively (p = .0043, .0087, and .0173). Partial discectomy and wide posterior release proved statistically equivalent.

CONCLUSIONS

Wide posterior release of the thoracolumbar spine allows significant correction and may be superior to inferior facetectomy in axial rotation. Although complete discectomy with PLL resection would likely allow greater correction, a more clinically realistic partial discectomy confers similar corrective potential in vitro compared with wide posterior release.

LEVEL OF EVIDENCE

Not applicable.

Anterior Spinal Fusion and Posterior Spinal Fusion Both Effectively Treat Lenke Type 5 Curves in Adolescent Idiopathic Scoliosis: A Multicenter Study

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Retrospective comparison of radiographic and clinical outcomes between anterior spinal fusion (ASF) and posterior spinal fusion (PSF) in surgical treatment of Lenke 5 curves.

SUMMARY OF BACKGROUND DATA

ASF and PSF are used for treatment of Lenke 5 curves in patients with adolescent idiopathic scoliosis (AIS). Currently, no consensus exists for optimal surgical treatment of Lenke 5 curves.

METHODS

Patients with Lenke 5 curves treated with either ASF or PSF were prospectively enrolled in a multicenter database and then retrospectively reviewed. Demographic data, perioperative measures, radiographic data, and SRS-22R scores were collected and compared for statistical significance.

RESULTS

A total of 149 patients were included in the study; 51 underwent PSF and 98 underwent ASF. There was no difference in demographics between groups. The PSF group was fused one level longer than the ASF group (5.9 levels PSF, 4.6 levels ASF, p < .0001). The PSF group had shorter operative times (223 minutes PSF, 297 minutes ASF; p < .0001) and a higher proportion of patients who received a postoperative blood transfusion (45% vs. 5%, p < .0001). PSF patients had longer hospital stays (6.1d PSF vs. 5d ASF, p = .031). The ASF group had larger preoperative major curve (48.2° ASF, 44.2° PSF; p < .01). Coronal balance, thoracolumbar/lumbar Cobb angle, shoulder height, trunk shift, and overall sagittal balance were not different between groups at two-year follow-up. Curve correction at two-year follow-up was similar between groups (66% ASF vs. 62% PSF). There were no significant differences in clinical outcomes or complication rates between groups.

CONCLUSION

There is no difference in radiographic or clinical outcomes in patients treated with ASF or PSF for Lenke 5 curves. ASF may save a fusion level, but has longer operative time than PSF. Ultimately, the risks and benefits of each approach merit consideration by surgeon and patient.

LEVEL OF EVIDENCE

Level II.

Comparison of Extending Fusion to Thoracic Curve Versus Thoracolumbar/Lumbar Fusion in Posterior Fusion of Patients with Lenke 5C: Variation in Upper End Vertebrae Tilt Affected Coronal Balance

BACKGROUND

Extended fusion can be performed in patients with Lenke 5C adolescent idiopathic scoliosis (AIS) with a large and relatively rigid thoracic curve. Progression of the thoracic curve is related to coronal imbalance. We aimed to determine the correlation between the upper instrumented vertebra choice and coronal balance in patients with Lenke 5C AIS.

METHODS

A total of 61 patients with Lenke 5C AIS underwent posterior fusion from 2009 to 2015 in a single institution with ≥2 years of follow-up data available. The extended fusion group (n = 32) and thoracolumbar/lumbar (TL/L) fusion group (n = 29) were compared for the correction rates for the main TL/L and thoracic curves, coronal balance, upper end vertebra (UEV) tilt, and Scoliosis Research Society-22 questionnaire score.

RESULTS

Both groups had excellent correction of the main TL/L curve, and the extended fusion group had a significantly greater correction rate of the thoracic curve than the TL/L fusion group (70.2% vs. 57.3%). The incidence of coronal imbalance was similar in both groups. The spontaneous change in UEV tilt was associated with the change in coronal balance from the first to the final follow-up examination. In the TL/L fusion group, the increase in UEV tilt from the first to final follow-up visit resulted in improved coronal balance at the final follow-up examination. Both groups had similar Scoliosis Research Society-22 questionnaire scores at 2 years postoperatively.

CONCLUSIONS

In patients with Lenke 5C AIS, thoracic curve fusion results in better correction of the thoracic curve but no improvement in coronal balance. With TL/L fusion, a postoperative UEV tilt >5° leads to better coronal balance.

A Detailed Comparative Analysis of Anterior Versus Posterior Approach to Lenke 5C Curves

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To prospectively compare radiographic, perioperative, and functional outcomes between anterior spinal instrumentation and fusion (ASIF) and posterior spinal instrumentation and fusion (PSIF) in Lenke 5C curves.

SUMMARY OF BACKGROUND DATA

Historically, ASIF has been the treatment of choice for treatment of thoracolumbar adolescent idiopathic scoliosis. More recently, PSIF has gained popularity for its ease, versatility, and amount of correction achieved. Current literature lacks a prospective comparative analysis between these two approaches to better aid treating surgeons in decision making when treating Lenke 5C curves.

METHODS

A prospective, longitudinal multicenter adolescent idiopathic scoliosis database was used to identify 161 consecutive patients with Lenke 5C curves treated by ASIF with a dual rod system, or PSIF with a pedicle screw-rod construct. Pre- and 2-year postoperative radiographic data, Scoliosis Research Society outcome scores, and perioperative comparisons were made between the two approaches.

RESULTS

A total of 69 patients were treated with ASIF and 92 patients with PSIF. Curve extent, magnitude, stable, and end vertebrae distribution before surgery were similar between the two groups. At 2-year follow-up, there were no significant differences in percentage correction of the main curve (ASIF: 59.1%, PSIF: 59.6%), C7 decompensation (ASIF: -0.6 ± 1.2, PSIF: -0.3 ± 1.4 cm), length of hospital stay (ASIF: 5.6 days, PSIF: 5.7 days), postoperative day conversion to oral pain medication (ASIF: 3.2 days, PSIF: 3.2 days), and SRS outcome scores (P = 0.560) between the two groups. The number of levels fused was significantly lower in ASIF group (ASIF: 4.7, PSIF: 6.3; P < 0.001), but PSIF resulted in significantly less disc angulation below lowest instrumented vertebrae (ASIF: 3.4°, PSIF: 1.7°; P = 0.011), greater lumbar lordosis (P < 0.001), and greater % correction of lumbar prominence (P = 0.017).

CONCLUSION

The amount of correction achieved was similar between ASIF and PSIF. ASIF resulted in shorter fusions (average 1.6 levels) compared with PSIF. This was at the expense of increased disc angulation below the lowest instrumented vertebrae, less lumbar lordosis, and a lower % correction of the lumbar prominence than PSIF.

LEVEL OF EVIDENCE

2.

Radiological factors affecting post-operative global coronal balance in Lenke 5 C scoliosis

Background

Lenke 5 C curves are frequently associated with clinically and radiological coronal imbalance. Appropriate selection of proximal and distal levels of fusion is essential to ensure good coronal balance (CB). We aimed to evaluate radiological factors associated with (I) global CB in the early post-operative period; (II) late decompensation of CB; and (III) favourable spontaneous correction of CB on long term follow up.

Methods

Twenty-three Lenke type 5C scoliosis cases treated with selective posterior lumbar instrumentation were retrospectively evaluated. Pre-operative, early post-operative and late post-operative (>2 years) whole length radiographs were analysed. Cobb's angle, lumbar lordosis, coronal imbalance, lower instrumented vertebra (LIV) tilt and translation and upper instrumented vertebra (UIV) tilt and translation were measured. The proximal and distal fusion levels were noted and correlated with post-operative CB.

Results

There were 21 females and 2 males with a mean follow up of 36 months. The mean pre-operative cobb angle was 55°±13.26°, which corrected to 14.7°±8.84° and was maintained on follow up. Eight patients had early post-operative coronal imbalance with spontaneous resolution seen in six cases on long term follow-up. At final follow-up, four cases had coronal imbalance (persistent imbalance since early post-operative period =2; late decompensation =2). In cases with early imbalance 5/8 cases had a pre-operative LIV tilt of ≥25°. All four patients with coronal imbalance at final follow-up had pre-operative LIV tilt ≥25°. Radiographic parameters which correlated with post-operative coronal imbalance were pre-operative LIV tilt (r=0.64, P=0.001), pre-operative LIV translation (r=0.696, P<0.001), pre-operative UIV translation (r=0.44, P=0.030), post-operative LIV tilt (r=0.804, P<0.001), and post-operative UIV tilt (r=0.62, P=0.001).

Conclusions

In Lenke 5C scoliosis, a pre-operative LIV tilt ≥25° significantly correlates with post-operative global coronal imbalance. Increasing UIV tilt may be a factor that accounts for improvement of CB in late follow-up period.

Minimally invasive scoliosis surgery assisted by O-arm navigation for Lenke Type 5C adolescent idiopathic scoliosis: a comparison with standard open approach spinal instrumentation

OBJECTIVE Recently, minimally invasive scoliosis surgery (MISS) was introduced for the correction of adult scoliosis. Multiple benefits including a good deformity correction rate and fewer complications have been demonstrated. However, few studies have reported on the use of MISS for the management of adolescent idiopathic scoliosis (AIS). The purpose of this study was to investigate the outcome of posterior MISS assisted by O-arm navigation for the correction of Lenke Type 5C AIS. METHODS The authors searched a database for all patients with AIS who had been treated with either MISS or PSF between November 2012 and January 2014. Levels of fusion, density of implants, operation time, and estimated blood loss (EBL) were recorded. Coronal and sagittal parameters were evaluated before surgery, immediately after surgery, and at the last follow-up. The accuracy of pedicle screw placement was assessed according to postoperative axial CT images in both groups. The 22-item Scoliosis Research Society questionnaire (SRS-22) results and complications were collected during follow-up. RESULTS The authors retrospectively reviewed the records of 45 patients with Lenke Type 5C AIS, 15 who underwent posterior MISS under O-arm navigation and 30 who underwent posterior spinal fusion (PSF). The 2 treatment groups were matched in terms of baseline characteristics. Comparison of radiographic parameters revealed no obvious difference between the 2 groups immediately after surgery or at the final follow-up; however, the MISS patients had significantly less EBL (p < 0.001) and longer operation times (p = 0.002). The evaluation of pain and self-image using the SRS-22 showed significantly higher scores in the MISS group (p = 0.013 and 0.046, respectively) than in the PSF group. Postoperative CT showed high accuracy in pedicle placement in both groups. No deep wound infection, pseudarthrosis, additional surgery, implant failure, or neurological complications were recorded in either group. CONCLUSIONS Minimally invasive scoliosis surgery is an effective and safe alternative to open surgery for patients with Lenke Type 5C AIS. Compared with results of the open approach, the outcomes of MISS are promising, with reduced morbidity. Before the routine use of MISS, however, long-term data are needed.

Radiographic evaluation of posterior selective thoracolumbar or lumbar fusion for moderate Lenke 5C curves

INTRODUCTION

Posterior selective thoracolumbar or lumbar (TL/L) fusion with pedicle screw constructs for adolescent idiopathic scoliosis (AIS) has been studied in a few researches. However, few studies have discussed the indication for selective TL/L fusion and the behaviors of its adjacent disc angle. The present study aims to discuss the indication for posterior selective TL/L fusion and the behavior of the adjacent disc angle.

METHODS

45 consecutive cases of AIS undergoing posterior selective TL/L fusion were retrospectively evaluated, with an average follow-up of 36 months. Radiographs were reviewed to determine the coronal curve magnitude and the sagittal alignment preoperatively, postoperatively and at final follow-up. Thoracic curves in groups A had a correction loss of more than 5°, while thoracic curves in group B had a correction loss of not more than 5°.

RESULTS

The coronal curve magnitude of the TL/L curve averaged 44° preoperatively and it was corrected to 6° immediately with a correction rate of 84.8 %. At final follow-up it was 9° with a correction loss of 3°. The minor thoracic curve was 26° preoperatively, and the convex side bending curve magnitude averaged 8° with a flexibility of 72.7 %. It was corrected to 13° immediately with a spontaneous correction of 48.5 %. At final follow-up it was 14° with a correction loss of 1°. UIVA decreased from 4° to 2° after surgery, and it was 2° at final follow-up. LIVA decreased from 7° to 4° after surgery, and it was 5° at final follow-up. Maximal correction of TL/L curves in group A is significantly less than that in group B. 1 patient received revision surgery to fuse the progressive thoracic curve.

CONCLUSION

Posterior selective TL/L fusion with pedicle screw constructs allows for spontaneous thoracic correction and maintains coronal and sagittal balance during the follow-up. Maximal correction instead of undercorrection was recommended for moderate Lenke 5C curves. Disc wedging could be improved after surgery and well maintained during the follow-up.

Higher Flexibility and Better Immediate Spontaneous Correction May Not Gain Better Results for Nonstructural Thoracic Curve in Lenke 5C AIS Patients: Risk Factors for Its Correction Loss

STUDY DESIGN

Retrospective study.

OBJECTIVE

To study the behavior of the unfused thoracic curve in Lenke type 5C during the follow-up and to identify risk factors for its correction loss.

SUMMARY OF BACKGROUND DATA

Few studies have focused on the spontaneous behaviors of the unfused thoracic curve after selective thoracolumbar or lumbar fusion during the follow-up and the risk factors for spontaneous correction loss.

METHODS

We retrospectively reviewed 45 patients (41 females and 4 males) with AIS who underwent selective TL/L fusion from 2006 to 2012 in a single institution. The follow-up averaged 36 months (range, 24-105 months). Patients were divided into two groups. Thoracic curves in group A improved or maintained their curve magnitude after spontaneous correction, with a negative or no correction loss during the follow-up. Thoracic curves in group B deteriorated after spontaneous correction with a positive correction loss. Univariate analysis and multivariate analysis were built to identify the risk factors for correction loss of the unfused thoracic curves.

RESULTS

The minor thoracic curve was 26° preoperatively. It was corrected to 13° immediately with a spontaneous correction of 48.5%. At final follow-up it was 14° with a correction loss of 1°. Thoracic curves did not deteriorate after spontaneous correction in 23 cases in group A, while 22 cases were identified with thoracic curve progressing in group B. In multivariate analysis, two risk factors were independently associated with thoracic correction loss: higher flexibility and better immediate spontaneous correction rate of thoracic curve.

CONCLUSION

Posterior selective TL/L fusion with pedicle screw constructs is an effective treatment for Lenke 5C AIS patients. Nonstructural thoracic curves with higher flexibility or better immediate correction are more likely to progress during the follow-up and close attentions must be paid to these patients in case of decompensation.

LEVEL OF EVIDENCE

4.

Lenke 5C Curves in Adolescent Idiopathic Scoliosis: Anterior vs Posterior Selective Fusion

BACKGROUND

The optimal treatment of Lenke 5C curves in adolescent idiopathic scoliosis is still unclear.

OBJECTIVE

To compare the outcomes and the spontaneous correction behavior between anterior and posterior selective fusion techniques in a large case series.

METHODS

Demographic and surgical data for patients with Lenke 5C curves treated with anterior or posterior fusion were collected from July 2002 to September 2011. Clinical assessment and radiographic parameters were compared preoperatively and postoperatively and at a minimum of 2 years of follow-up.

RESULTS

Fifty-three Lenke 5C adolescent idiopathic scoliosis cases with an average follow-up of 4 years (range, 2-9.6 years) were included. The clinical scores were similar between the 2 groups. Postoperative major thoracic curvature changes were similar. The minor thoracic curve demonstrated a higher spontaneous correction rate in the posterior group. At follow-up, the minor thoracic curve showed a greater loss of correction in the posterior group, and finally both groups were comparable. Surgical time, intraoperative blood loss, and complications were comparable. A total of 5 patients had a final thoracic curve larger than the preoperative degrees.

CONCLUSION

Selective fusion of the major thoracolumbar/lumbar curve in Lenke 5C adolescent idiopathic scoliosis can be achieved by anterior and posterior techniques. The spontaneous correction of the unfused thoracic curve was comparable after an average of 4 years follow-up.

Biomechanical Comparison of Expansive Pedicle Screw and Polymethylmethacrylate-augmented Pedicle Screw in Osteoporotic Synthetic Bone in Primary Implantation: An Experimental Study

STUDY DESIGN

Expansive pedicle screws (EPS) and polymethylmethacrylate-augmented pedicle screws (PMMA-PS) were inserted into osteoporotic synthetic bones, which were then tested by radiographic and biomechanical examinations.

OBJECTIVE

To compare the stability of EPS and PMMA-PS with that of a conventional pedicle screw (CPS) in an osteoporotic synthetic bone.

SUMMARY OF BACKGROUND DATA

It is a significant challenge for orthopedic surgeons performing transpedicular fixation in the osteoporotic spine. Prior studies have suggested that both EPS and PMMA-PS can increase the screw stability effectively. However, there are no biomechanical comparisons of EPS and PMMA-PS, especially in primary spinal surgery in osteoporosis.

METHODS

Thirty osteoporotic synthetic bone blocks were divided into 3 groups randomly. A pilot hole was prepared in advance in all samples by the same method. Then, the CPS was inserted directly into the pilot hole in the CPS group; the hole in the PMMA-PS group was first filled with polymethylmethacrylate (PMMA; 2.5 mL) and then inserted with CPS, and the EPS was inserted directly into the blocks in the EPS group. Twenty-four hours later, x-ray and computed tomography examination and axial pullout tests were performed on all samples; the block destructions were then recorded, and the hole diameters were measured.

RESULTS

In the CPS group, the screw was surrounded directly by the synthetic bone without any other materials, whereas in the PMMA-PS group, the screw was totally wrapped up by PMMA, and the PMMA was evenly distributed in the synthetic bone around the screw, indicating obvious improvement of the local density around the track. In the EPS group, the anterior part of the EPS presented an obvious expansion in synthetic bone and formed an unguiform structure pressing the surrounding synthetic bone. Screw stabilities in both the PMMA-PS and the EPS groups were significantly enhanced compared with those in the CPS group, and the screw stability in the PMMA-PS group was significantly higher than that in the EPS group. After the pullout tests, the block destructions were the most severe in the PMMA-PS group and the lightest in the CPS group. Hole diameters in the PMMA-PS and the EPS groups were significantly larger than that in the CPS group, whereas the diameter of the hole in the PMMA-PS group was significantly greater than that in the EPS group.

CONCLUSIONS

EPS can significantly increase the strength of screw fixation compared with CPS in osteoporotic synthetic bone. Although EPS shows a weaker fixation strength compared with PMMA-PS in the osteoporotic synthetic bone, it may still provide an alternative option to prevent screw loosening in the clinical treatment of osteoporosis.

Anterior versus posterior approach in Lenke 5C adolescent idiopathic scoliosis: a meta-analysis of fusion segments and radiological outcomes

Background

Radiological outcomes between anterior and posterior approach in Lenke 5C curves were still controversial. Meta-analysis on published articles to compare fusion segments and radiological outcomes between the two surgical approaches was performed.

Methods

Electronic database was conducted for searching studies concerning the anterior versus posterior approach in Lenke 5C curves. After quality assessment, data of means, standard deviations, and sample sizes were extracted. RevMan 5.3 was adopted for data analysis.

Results

Seven case-control studies involving 308 Lenke 5C AIS patients were identified in the meta-analysis. No significant differences were noted in correction rate of thoracolumbar/lumbar curve (95 % CI −6.02 to 4.32, P = 0.75) and incidence of proximal junctional kyphosis (95 % CI 0.12 to 7.19, P = 0.94) of final follow-up, in change values of thoracolumbar/lumbar curve (95 % CI −3.28 to 7.19, P = 0.46) and thoracic kyphosis (95 % CI −4.10 to 0.13, P = 0.07). The anterior approach represented a significant shorter fusion segments compared to posterior approach (95 % CI −1.72 to −0.71, P < 0.00001). The posterior approach obtained a larger increasing Cobb angle of lumbar lordosis than the anterior approach (95 % CI −6.06 to −0.61, P = 0.02).

Conclusions

The anterior and posterior approach can obtain comparable coronal correction, change values of thoracic kyphosis, and incidence of proximal junctional kyphosis. The anterior approach saves approximate one more fusion segment, and the posterior approach can obtain a larger increasing Cobb angle of lumbar lordosis, from preoperation to final follow-up.

Trial registration

The article type of this study is meta-analysis and prospective registration is not required.

Prevalence and Consequences of the Proximal Junctional Kyphosis After Spinal Deformity Surgery: A Meta-Analysis

The aim of this study was to estimate the prevalence and patient outcomes of proximal junctional kyphosis (PJK) in pediatric patients and adolescents who received surgical interventions for the treatment of a spinal deformity.Literature was searched in electronic databases, and studies were selected by following précised eligibility criteria. Percent prevalence values of the PJK in individual studies were pooled to achieve a weighted effect size under the random effects model. Subgroup and meta-regression analyses were performed to appraise the factors affecting PJK prevalence.Twenty-six studies (2024 patients) were included in this meta-analysis. Average age of the patients was 13.8 ± 2.75 years of which 32 ± 20 % were males. Average follow-up was 51.6 ± 38.8 (range 17 ± 13 to 218 ± 60) months. Overall, the percent prevalence of PJK (95% confidence interval) was 11.02 (10.5, 11.5) %; P < 0.00001 which was inversely associated with age (meta-regression coefficient: -1.607 [-2.86, -0.36]; 0.014). Revision surgery rate in the patients with PJK was 10%. The prevalence of PJK was positively associated with the proximal junctional angle at last follow-up (coefficient: 2.248; P = 0.012) and the change in the proximal junctional angle from surgery to last follow-up (coefficient: 2.139; P = 0.014) but not with preoperative proximal junctional angle.The prevalence of PJK in the children and adolescent patients is 11%. About 10% of those affected require revision surgery.

Selection of Fusion Levels Using the Fulcrum Bending Radiograph for the Management of Adolescent Idiopathic Scoliosis Patients with Alternate Level Pedicle Screw Strategy: Clinical Decision-making and Outcomes

Objective

Selecting fusion levels based on the Luk et al criteria for operative management of thoracic adolescent idiopathic scoliosis (AIS) with hook and hybrid systems yields acceptable curve correction and balance parameters; however, it is unknown whether utilizing a purely pedicle screw strategy is effective. Utilizing the fulcrum bending radiographic (FBR) to assess curve flexibility to select fusion levels, the following study assessed the efficacy of pedicle screw fixation with alternate level screw strategy (ALSS) for thoracic AIS.

Methods

A retrospective study with prospective radiographic data collection/analyses (preoperative, postoperative 1-week and minimum 2-year follow-up) of 28 operative thoracic AIS patients undergoing ALSS was performed. Standing coronal/sagittal and FBR Cobb angles, FBR flexibility, fulcrum bending correction index (FBCI), trunkal shift, radiographic shoulder height (RSH), and list were assessed on x-rays. Fusion level selection was based on the Luk et al criteria and compared to conventional techniques.

Results

In the primary curve, the mean preoperative and postoperative 1 week and last follow-up standing coronal Cobb angles were 59.9, 17.2 and 20.0 degrees, respectively. Eighteen patients (64.3%) had distal levels saved (mean: 1.6 levels) in comparison to conventional techniques. Mean immediate and last follow-up FBCIs were 122.6% and 115.0%, respectively. Sagittal alignment did not statistically differ between any assessment intervals (p>0.05). A decrease in trunkal shift was noted from preoperative to last follow-up (p = 0.003). No statistically significant difference from preoperative to last follow-up was noted in RSH and list (p>0.05). No "add-on" of other vertebra or decompensation was noted and all patients achieved fusion.

Conclusions

This is the first report to note that using the FBR for decision-making in selecting fusion levels in thoracic AIS patients undergoing management with pedicle screw constructs (e.g. ALSS) is a cost-effective strategy that can achieve clinically-relevant deformity correction that is maintained and without compromising fusion levels.

Spontaneous Thoracic Curve Correction After Selective Posterior Fusion of Thoracolumbar/Lumbar Curves in Lenke 5C Adolescent Idiopathic Scoliosis

Selective fusion of the thoracolumbar/lumbar (TL/L) curve is an effective method for the treatment of Lenke type 5C curves. Several studies have demonstrated that spontaneous correction of the thoracic curve does indeed occur. However, how this correction occurs after isolated posterior segmental instrumentation of the structural lumbar curve has not been well described. The aim of this study was to evaluate the response of the thoracic curve to selective TL/L curve fusion in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS) and assess the correlative clinical outcomes. Thirty-four consecutive patients with Lenke type 5C AIS were included in this study. All patients underwent selective TL/L curve instrumentation and fusion via the posterior approach. Coronal and sagittal radiographs were analyzed before surgery, at 1 week after surgery and at least 2 years after surgery. The preoperative coronal Cobb angle of the major TL/L curve was 45.4° ± 7.0°, and that of the minor thoracic curve was 25.4° ± 8.8°. The major TL/L and minor thoracic curves were corrected to postoperative angles of 9.5° ± 5.0° and 11.2° ± 5.2°, respectively, and measured 10.5° ± 6.0° and 13.4° ± 7.5° at the follow-up, respectively. The supine side-bending average Cobb angle of the thoracic curve was 9.9°. These results demonstrate satisfactory improvements because of coronal and sagittal restoration. Significant correlations were found between the preoperative and early postoperative conditions and the Cobb angle changes of the minor thoracic curve and the major TL/L curves (r = 0.42, P = 0.01). Significant correlations were also observed between the early and final follow-up postoperative conditions and the Cobb angle changes of the minor thoracic curve and the major TL/L curves (r = 0.57, P < 0.001). Significant correlations were observed between increased thoracic kyphosis (TK) and increased lumbar lordosis (LL) in the preoperative and early postoperative conditions (r = 0.36, P = 0.035) and between increased TK and increased LL in the preoperative and final follow-up postoperative conditions (r = 0.51, P = 0.002). Spontaneous correction of the thoracic curve is a reflection of the TL/L curve correction in Lenke 5C AIS patients. Supine side-bending radiographs are an effective method of predicting the spontaneous correction of thoracic curves. The correction of LL is important for maintaining spinal sagittal alignment.

Evaluation of idiopathic scoliosis by anterior and posterior arthrodesis

<sec><title>OBJECTIVE:</title><p> To evaluate comparatively surgical treatment of adolescent idiopathic scoliosis type 5CN by anterior and posterior approach.</p></sec><sec><title>METHODS:</title><p> The study consists of a comparative retrospective study of two groups of patients with the thoracolumbar spine arthrodesis technique by anterior and posterior approach. Twenty and two patients were sequentially selected, 11 operated by anterior approach - called Group I - and 11 by posterior approach - Group II. Anamnesis and physical examination were performed, as well as length of hospital stay and ICU stay, degree of correction, comorbidities and pre and postoperative radiographic images data were gathered.</p></sec><sec><title>RESULTS:</title><p> The mean age was 13.7 years in Group I and 14 years in Group II. The average hospital stay was 5.81 days for Group I and 5 for Group II. The average ICU stay was 2.81 and 2 days, respectively. Considering the operated levels, Group I presented an average of 4.81 vertebrae (4-6 levels), and Group II presented an average of 6.36 vertebrae (5-11 levels). Complications did not show statistically significant difference.</p></sec><sec><title>CONCLUSION:</title><p> Despite the limited number of patients in groups, it was demonstrated that the posterior approach reduces the number of days of hospitalization and ICU stay. However, it was found increased levels included in the arthrodesis.</p></sec>

Posterior spinal fusion for adolescent idiopathic thoracolumbar/lumbar scoliosis

Clinical, radiological, and Scoliosis Research Society-22 questionnaire data were reviewed pre-operatively and two years post-operatively for patients with thoracolumbar/lumbar adolescent idiopathic scoliosis treated by posterior spinal fusion using a unilateral convex segmental pedicle screw technique. A total of 72 patients were included (67 female, 5 male; mean age at surgery 16.7 years (13 to 23)) and divided into groups: group 1 included 53 patients who underwent fusion between the vertebrae at the limit of the curve (proximal and distal end vertebrae); group 2 included 19 patients who underwent extension of the fusion distally beyond the caudal end vertebra.

A mean scoliosis correction of 80% (45% to 100%) was achieved. The mean post-operative lowest instrumented vertebra angle, apical vertebra translation and trunk shift were less than in previous studies. A total of five pre-operative radiological parameters differed significantly between the groups and correlated with the extension of the fusion distally: the size of the thoracolumbar/lumbar curve, the lowest instrumented vertebra angle, apical vertebra translation, the Cobb angle on lumbar convex bending and the size of the compensatory thoracic curve. Regression analysis allowed an equation incorporating these parameters to be developed which had a positive predictive value of 81% in determining whether the lowest instrumented vertebra should be at the caudal end vertebra or one or two levels more distal. There were no differences in the Scoliosis Research Society-22 outcome scores between the two groups (p = 0.17).

In conclusion, thoracolumbar/lumbar curves in patients with adolescent idiopathic scoliosis may be effectively treated by posterior spinal fusion using a unilateral segmental pedicle screw technique. Five radiological parameters correlate with the need for distal extension of the fusion, and an equation incorporating these parameters reliably informs selection of the lowest instrumented vertebra.

Cite this article: Bone Joint J 2014;96-B:1082–9.

Fusionless instrumentation in growing spine and adjacent segment problems: an experimental study in immature pigs

STUDY DESIGN

Experimental study.

OBJECTIVE

To compare the effects of fusionless instrumentation (FI) and instrumented fusion (IF) on the adjacent segment in an immature pig model.

SUMMARY OF BACKGROUND DATA

Observations reveal proximal junctional kyphosis after FI. Possible reasons are stress concentration, repeated distractive forces, and/or soft tissue damage done in the index surgery. It was speculated that FI can decrease stressors to the junctional area by preserving the spinal mobility in some manner; however, this has not been proven to date.

METHODS

Thirteen piglets of 10- to 14-week age were used. FI and IF were performed on 7 and 3 piglets, respectively, and 3 piglets formed the control group. Control piglets did not undergo any surgical procedures. T11-L4 instrumentation, decortication, and grafting were applied to IF piglets. In FI groups, however, L1-L2 was left uninstrumented and unfused using T11-T12 and L3-L4 levels as anchors to the growing construct. A total of 4 lengthening procedures were performed: 1 in the index operation and 3 more, once in each lengthening procedure monthly, for 3 months. Four months after the index operations, all piglets were killed and the adjacent segment motion capabilities, disc, and facets were evaluated with radiographical, magnetic resonance imaging, biomechanical, and histological analyses.

RESULTS

Comparison of proximal junctional Cobb angles of the postindex (mean: 21, range: 17-27) and presacrification (mean: 21, range: 11-31) radiographs in the FI group revealed no difference (P> 0.05). In magnetic resonance imaging, both surgical group proximal adjacent discs showed degeneration to some degree that was statistically indifferent (P = 0.903). Biomechanical evaluation revealed restriction of adjacent segment motion in all directions for both groups; however, this negative effect was significantly less in FI group (P < 0.01). Degeneration observed in histological evaluation in adjacent discs and facets of FI group was significantly lower (P = 0.00).

CONCLUSION

In this quadruped straight spine model, in comparison with IF applications, FI is closer to normal physiology even after several lengthening procedures regarding the adjacent segment discs, facet joints, and motion, when interpreting the radiological, biomechanical, and histological results altogether.

Should Shoulder Balance Determine Proximal Fusion Levels in Patients With Lenke 5 Curves?

STUDY DESIGN

Multicenter review of prospectively collected data.

OBJECTIVES

To identify the frequency of an opposite high shoulder in Lenke 5 patients and evaluate factors that influence preoperative and postoperative shoulder balance.

SUMMARY OF BACKGROUND DATA

A high left shoulder is an indication to extend the fusion proximally in a right thoracic curve. Some apply a similar rule to high right shoulders in patients with left thoracolumbar/lumbar curves.

METHODS

A prospective multicenter adolescent idiopathic scoliosis database was queried for patients with Lenke 5 curves and minimum 2-year follow-up. Preoperative and postoperative shoulder height differences were recorded and categorized by the opposite shoulder (right shoulder in a left thoracolumbar curve) as high (greater than 1 cm), level (0-1 cm), and low (less than 1 cm). Preoperative and postoperative radiographic variables and Scoliosis Research Society questionnaire scores were evaluated.

RESULTS

Of the 104 patients identified, 37% had level shoulders and 53% had a high opposite shoulder. A high shoulder was associated with a greater mean thoracic Cobb (31°) than a level (24°) or low shoulder (26°) (p = .008). Postoperatively, 64% of patients had level shoulders (less than 1 cm); 93% had a shoulder difference less than 2 cm. Preoperative lumbar Cobb was a significant predictor of postoperative shoulder height (p = .051). A slightly greater proportion of preoperative high shoulders (36%) had a nonselective fusion than those with level (27%) or low (9%) shoulders. Among the 29 patients with a preoperative moderate or significant high shoulder (greater than 2 cm), 3 continued to have a high shoulder greater than 2 cm that was not influenced by fusing the thoracic spine. There were no significant differences in preoperative or postoperative Scoliosis Research Society scores based on shoulder height (p > .05).

CONCLUSIONS

Half of all Lenke 5 curves have a high opposite shoulder that is influenced by the size of the compensatory thoracic curve. Postoperatively, most patients had level shoulders. Inclusion of the thoracic spine did not influence postoperative shoulder balance.

The posterior pedicle screw construct: 5-year results for thoracolumbar and lumbar curves

OBJECT

Several studies of the outcomes of patients with adolescent idiopathic scoliosis (AIS) with thoracolumbar and lumbar curves after treatment with posterior pedicle screws have been reported, but most of these studies reported only 2-year follow-up. The authors analyzed the radiographic and clinical outcomes of patients with thoracolumbar and lumbar curves treated with posterior pedicle screws after 5 years of follow-up.

METHODS

A multicenter database was retrospectively queried to identify patients with AIS who underwent spinal fusion for Lenke 3C, 5C, and 6C curves. Radiographs from the following times were compared: preoperative, first follow-up visit, 1-year follow-up visit, 2-year follow-up visit, and 5-year follow-up visit. Chart review included scoliometer measurements, Scoliosis Research Society (SRS)-22 questionnaires, and complications requiring return to the operating room.

RESULTS

Among 26 patients with Lenke 3C, 5C, and 6C curves, the mean (± SD) age was 14.6 ± 2.1 years. From the time of the preoperative radiographs to the 5-year follow-up radiographs, there was a statistically significant improvement in the mean coronal lumbar Cobb angles (p < 0.0001), and from the time of the first postoperative radiographs to the 5-year follow-up radiographs, the lumbar curve remained stable (p = 0.14). From the time of the preoperative radiographs to the 5-year follow-up radiographs, there was a statistically significant improvement in the mean coronal thoracic Cobb angles (p < 0.0001), and from the time of the first postoperative radiographs to the 5-year follow-up radiographs, the thoracic curve remained stable (p = 0.10). From the first postoperative visit to the 5-year follow-up visit, the thoracic kyphosis (T5-12) remained stable (p = 0.10), and from the time of the preoperative radiographs to the 5-year follow-up radiographs, the lumbar lordosis (T-12 to top of sacrum) remained stable (p = 0.44). From the preoperative visit to the 5-year follow-up visit, the coronal balance improved significantly (p < 0.05) and remained stable from the first postoperative visit to the 5-year follow-up visit (p = 0.20). The SRS-22 total scores improved significantly from before surgery to 5 years after surgery (p < 0.0001). No patients required reoperation because of complications.

CONCLUSIONS

Correction of the coronal, sagittal, and axial planes in this cohort of patients was maintained from the first follow-up measurements to 5 years after surgery. In addition, at 5 years after surgery total SRS-22 scores and inclinometer readings were improved from preoperative scores and measurements.

Comparison of expansive pedicle screw and polymethylmethacrylate-augmented pedicle screw in osteoporotic sheep lumbar vertebrae: biomechanical and interfacial evaluations

Background

It was reported that expansive pedicle screw (EPS) and polymethylmethacrylate-augmented pedicle screw (PMMA-PS) could be used to increase screw stability in osteoporosis. However, there are no studies comparing the two kinds of screws in vivo. Thus, we aimed to compare biomechanical and interfacial performances of EPS and PMMA-PS in osteoporotic sheep spine.

Methodology/Principal Findings

After successful induction of osteoporotic sheep, lumbar vertebrae in each sheep were randomly divided into three groups. The conventional pedicle screw (CPS) was inserted directly into vertebrae in CPS group; PMMA was injected prior to insertion of CPS in PMMA-PS group; and the EPS was inserted in EPS group. Sheep were killed and biomechanical tests, micro-CT analysis and histological observation were performed at both 6 and 12 weeks post-operation. At 6-week and 12-week, screw stabilities in EPS and PMMA-PS groups were significantly higher than that in CPS group, but there were no significant differences between EPS and PMMA-PS groups at two study periods. The screw stability in EPS group at 12-week was significantly higher than that at 6-week. The bone trabeculae around the expanding anterior part of EPS were more and denser than that in CPS group at 6-week and 12-week. PMMA was found without any degradation and absorption forming non-biological “screw-PMMA-bone” interface in PMMA-PS group, however, more and more bone trabeculae surrounded anterior part of EPS improving local bone quality and formed biological “screw-bone” interface.

Conclusions/Significance

EPS can markedly enhance screw stability with a similar effect to the traditional method of screw augmentation with PMMA in initial surgery in osteoporosis. EPS can form better biological interface between screw and bone than PMMA-PS. In addition, EPS have no risk of thermal injury, leakage and compression caused by PMMA. We propose EPS has a great application potential in augmentation of screw stability in osteoporosis in clinic.

Adolescent scoliosis classification and treatment

Adolescent idiopathic scoliosis (AIS) affects up to 3% of the population. It can be stratified by curve type according to the Lenke classification. This classification system incorporates curve magnitude, flexibility, the lumbar modifier, and the sagittal plane. The Lenke classification serves as a guide for selection of levels for surgical treatment of AIS. Surgical treatment of AIS includes anterior and posterior approaches; most AIS is treated through a posterior approach. Surgical goals include maximizing correction in the coronal, sagittal, and axial planes.

A comparison of anterior and posterior instrumentation for restoring and retaining sagittal balance in patients with idiopathic adolescent scoliosis

STUDY DESIGN

Retrospective, comparative study.

OBJECTIVE

To compare the effects of anterior rod-screw instrumentation and posterior pedicle screw instrumentation on sagittal balance in patients with Lenke type 5 adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Lenke type 5 AIS is treated by anterior or posterior spinal fusion surgery. Most studies comparing anterior and posterior fusion surgery have focused on assessing improvement in coronal balance. Studies comparing the effects of anterior and posterior surgery on sagittal balance are lacking.

METHODS

The records of 49 patients diagnosed with Lenke type 5 AIS were examined. A total of 21 patients underwent anterior surgery between 2000 and 2003, while 26 underwent posterior surgery between 2004 and 2006. Preoperative, postoperative, and follow-up thoracic kyphosis (T5-T12 and T2-T12), lumbar lordosis, thoracolumbar junction kyphosis, and spinal vertical axis measurements were made by examining radiographs. Quality of life was assessed using the Scoliosis Research Society-22 questionnaire. All patients were followed up for at least 2 years.

RESULTS

There were no significant between group differences in coronal alignment, thoracic kyphosis, or T11-L2 alignment after surgery. Sagittal alignment improvement was significantly more pronounced in the anterior surgery group compared with the posterior surgery group. The fusion segment was also significantly shorter in the anterior surgery compared with the posterior surgery group. Quality of life scores were significantly higher in the anterior surgery group compared with the posterior surgery group.

CONCLUSION

Anterior solid rod-screw instrumentation results in shorter fusion segments, and better sagittal alignment and quality of life than posterior pedicle screw instrumentation in patients with Lenke type 5 AIS.

Anterior versus posterior approach in the treatment of chronic thoracolumbar fractures

The purpose of this study was to compare the results of anterior approach vs posterior approach in the treatment of chronic thoracolumbar fractures. A total of 36 patients with chronic thoracolumbar fractures were divided into 2 groups. Group A was treated by an anterior approach and group B was treated by a posterior approach. During the minimum 24-month follow-up period (range, 24-62 months), all patients were prospectively evaluated for clinical and radiologic outcomes. Intraoperative blood loss, operative time, operative complications, pulmonary function, Frankel scale, and American Spinal Injury Association (ASIA) motor score were used for clinical evaluation, and Cobb angle was examined for radiologic outcome. All patients in this study achieved solid fusion, with significant neurologic improvement. Operative time, perioperative blood loss, ASIA score on admission and at final follow-up, and complications of respiratory tract infection and intercostal nerve pain were not significantly different between the 2 groups (P>.05), but complications of hemopneumothorax, abdominal distension, and constipation were fewer in group B (P<.05). Postoperative pulmonary function (P<.05) and correction of posttraumatic kyphosis were better in group B (P<.05).

Fixation points within the main thoracic curve: does more instrumentation produce greater curve correction and improved results?

STUDY DESIGN

Prospective consecutive multicenter case series.

OBJECTIVE

To compare fixation type and amount to curve correction controlled for curve flexibility.

SUMMARY OF BACKGROUND DATA

The enhanced spinal purchase from segmental fixation should increase the force implants can exert without failure. This study evaluates whether this translates into correction beyond that expected from preoperative bending radiographs in thoracic curves where maximum correction was feasible (1A, 1B, and nonselective 1C fusions).

METHODS

One hundred seventy-one Lenke type 1 curves (118 1A, 36 1B, 23 1C) with 2-year follow-up were evaluated for the number and type of fixation points within the main curves compared to the correction obtained on preoperative bend films. SRS scores were compared to the amount of correction.

RESULTS

The number of fixation points both within the curve (P = 0.01) and for each vertebral body (P = 0.002) was larger for curves with greater correction compared to the bend films than those with less correction. Overall absolute correction was best for all screw and screw and wire constructs, followed by hook and screw, and least with hooks. However, compared to the bend films, these differences were not significant (P = 0.132). For all groups, the SRS scores significantly improved (P < 0.001), and was slightly more notable for the all screw constructs than other instrumentation patterns (P = 0.023). However, there were no significant difference in this improvement between those correcting more and those correcting less than the bend films (P = 0.578).

CONCLUSION

Absolute curve correction improved most with all pedicle screw and screw and wire constructs, but, when compared to bending films, the number of fixation points is more important than fixation type for curve correction. Although SRS scores improved the most in those with all screw constructs, the significance of this improvement is uncertain, and the SRS scores did not relate to whether curve correction was more or less than the bend films.

Biomechanical comparison of different techniques in primary spinal surgery in osteoporotic cadaveric lumbar vertebrae: expansive pedicle screw versus polymethylmethacrylate-augmented pedicle screw

INTRODUCTION

Transpedicular fixation can be challenging in the osteoporotic spine. Expansive pedicle screw (EPS) and polymethylmethacrylate-augmented pedicle screw (PMMA-PS) were both used to increase screw stability. However, there are a little or no biomechanical comparisons of EPS and PMMA-PS, especially in primary spinal surgery in osteoporotic vertebrae. The purpose of this study was to compare the stability of EPS and PMMA-PS in primary spinal surgery.

MATERIALS AND METHODS

Fifteen osteoporotic vertebrae were randomly divided into three groups. The conventional pedicle screw (CPS) was inserted in CPS group, the pilot hole was filled with PMMA followed by CPS insertion in PMMA-PS group, and EPS was inserted in EPS group. Twenty-four hours later, X-ray and CT examination and biomechanical tests were performed to all vertebrae.

RESULTS

In PMMA-PS group, PMMA existed in bone tissue around the CPS in both vertebral body and pedicle of vertebral arch, and PMMA surrounding the screw formed a spindle-shaped structure in vertebral body. In EPS group, anterior part of EPS presented an obvious expansion in vertebral body and formed a clawlike structure. Screw stabilities in PMMA-PS and EPS groups were significantly enhanced compared with those in CPS group (P < 0.05). However, there was no significant difference between PMMA-PS and EPS groups (P > 0.05).

CONCLUSION

Expansive pedicle screw can markedly enhance screw stability with a similar effect to the traditional method of screw augmentation with PMMA in primary surgery in osteoporotic vertebrae. In addition, EPS can overcome pedicle fracture, leakage and compression caused by lager screw and augmentation with PMMA. We propose that EPS is an effective, safe and easy method and has a great application potential in augmentation of screw stability in osteoporosis in clinic.

Video-assisted thoracoscopic surgery plus lumbar mini-open surgery for adolescent idiopathic scoliosis

PURPOSE

The objectives of this study are to describe the outcome of adolescent idiopathic scoliosis (AIS) patients treated with Video Assisted Thoracoscopic Surgery (VATS) plus supplementary minimal incision in the lumbar region for thoracic and lumbar deformity correction and fusion.

MATERIALS AND METHODS

This is a case series of 13 patients treated with VATS plus lumbar mini-open surgery for AIS. A total of 13 patients requiring fusions of both the thoracic and lumbar regions were included in this study: 5 of these patients were classified as Lenke type 1A and 8 as Lenke type 5C. Fusion was performed using VATS up to T12 or L1 vertebral level. Lower levels were accessed via a small mini-incision in the lumbar area to gain access to the lumbar spine via the retroperitoneal space. All patients had a minimum follow-up of 1 year.

RESULTS

The average number of fused vertebrae was 7.1 levels. A significant correction in the Cobb angle was obtained at the final follow-up (p = 0.001). The instrumented segmental angle in the sagittal plane was relatively well-maintained following surgery, albeit with a slight increase. Scoliosis Research Society-22 (SRS-22) scores were noted have significantly improved at the final follow-up (p < 0.05).

CONCLUSION

Indications for the use of VATS may be extended from patients with localized thoracic scoliosis to those with thoracolumbar scoliosis. By utilizing a supplementary minimal incision in the lumbar region, a satisfactory deformity correction may be accomplished with minimal post-operative scarring.

Comparação do desfecho radiográfico das escolioses idiopáticas do adolescente tratadas com instrumentação híbrida, parafusos pediculares ou ganchos

OBJETIVOS: comparar os resultados radiográficos dos pacientes portadores de escoliose idiopática do adolescente (EIA) tratados cirurgicamente, com instrumentação com ganchos, híbrida ou parafusos pediculares, com seguimento mínimo de um ano. MÉTODOS: avaliação radiográfica retrospectiva dos pacientes portadores de escoliose idiopática do adolescente tratados com diferentes instrumentações, nos períodos pré-operatório, pós-operatório imediato e pós-operatório de um ano utilizando o método de medição de Cobb. RESULTADOS: não houve diferença estatística no comportamento das curvas durante o primeiro ano de seguimento nas curvas torácica, lombar ou na cifose. Quando analisadas de forma quantitativa, não se encontrou diferença estatística nas curvas torácica (p=0,052) e lombar (p=0,332) no período pré-operatório entre os três grupos. Os três instrumentais apresentaram comportamento semelhante, não havendo diferença quantitativa na correção das curvas torácica (p=0,052) e lombar (p=0,267) nos períodos pós-operatório imediato e após um ano de seguimento. CONCLUSÕES: as três estratégias de instrumentação rendem resultados radiográficos similares em pacientes portadores de EIA flexíveis.

Risk factor analysis of proximal junctional kyphosis after posterior fusion in patients with idiopathic scoliosis

STUDY DESIGN

A retrospective analysis of 150 adolescents who underwent spinal fusion for idiopathic scoliosis.

OBJECTIVE

To analyse the incidence of the postoperative proximal junctional kyphosis after posterior fusion to the upper thoracic vertebra in adolescents with idiopathic scoliosis and to explore its risk factors.

SUMMARY OF BACKGROUND DATA

The reported incidence of the proximal junctional kyphosis after the posterior fusion in patients with idiopathic scoliosis varies depending on surgical methods and strategies adopted by the institution.

METHODS

The changes in the Cobb angle of the proximal junctional kyphosis on the lateral spine X-ray were measured and the presence of PJK was recorded. The risk factors were screened using statistical analysis.

RESULTS

PJK occurred in 35 out of 123 patients with an overall incidence of 28%. Among them, 28 patients (80%) experienced PJK within 1.5 years after surgery. The PJK-inducing factors included greater than 10 degrees intraoperative decrease in thoracic kyphosis, thoracoplasty, the use of a pedicle screw at the top vertebra, autogenous bone graft and fusion to the lower lumbar vertebra (below L2).

CONCLUSIONS

There is a high incidence of postoperative proximal junctional kyphosis after posterior fusion to the upper thoracic vertebra within 1.5 years after surgery in adolescents with idiopathic scoliosis. In order to reduce its incidence, the risk factors for PJK should be carefully evaluated before surgery.

[Selective fusion of idiopathic scoliosis with respect to the Lenke classification]

Indications for surgical treatment of idiopathic scoliosis are progressive curves greater than 40-50 degrees. In most cases, fusion of only the primary (structural) curve(s) is sufficient due to the flexibility and spontaneous correction of the secondary curves. Therefore, it is crucial to identify both primary and secondary curves. According to the Lenke classification, all curves with a residual curve of more than 25 degrees on the bending films and those with a pathological kyphosis are regarded as structural and should be fused, whereas the nonstructural curves can be left unfused. However, according to reports in the literature and to the author's experience, clinical parameters such as shoulder level and rib or lumbar hump as well as radiometric criteria such as rotation are relevant as well. In summary, the Lenke classification is an important and helpful tool for analysing idiopathic curves and determining fusion length, even though each scoliosis case needs to be evaluated individually, especially taking clinical parameters into account.

Comparison of selective anterior versus posterior screw instrumentation in Lenke5C adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective review of anterior and posterior fusions for treatment of Lenke5C adolescent idiopathic scoliosis (AIS).

OBJECTIVE

To compare the clinical and radiographic results of anterior versus posterior pedicle screw instrumentation in Lenke5C AIS.

SUMMARY OF BACKGROUND DATA

Anterior and posterior pedicle screw instrumentations are 2 established methods of correcting Lenke5C AIS. However, there are few reports that compare the 2 methods.

METHODS

Forty-six consecutive patients with Lenke5C AIS curves underwent selective lumbar or thoracolumbar fusion (1999-2005). Twenty-two patients had anterior surgery, and 24 patients had posterior surgery. Patients were evaluated at a minimum 2-year follow-up.

RESULTS

No complications occurred in either group. The number of levels involved in the major curve was similar for the anterior and posterior groups (5.5 vs. 5.7). Preoperative thoracic (24.13 degrees +/- 4.9 degrees vs. 22.88 degrees +/- 5.14 degrees) and lumbar/thoracolumbar (50.2 degrees +/- 7.52 degrees vs. 52.2 degrees +/- 6.40 degrees). Cobb values for the 2 groups were also similar. The percent correction of the lumbar curve was similar between the 2 groups at all stages of follow-up (56% vs. 57.7%), as was the percent of spontaneous correction of the unfused thoracic curve (25% vs. 27.2%). However, fusion levels were significantly shorter in the anterior group (mean, 5.09 vs. 6.13), and there were 8 patients (4 in the anterior group and 4 in the posterior group) whose thoracic curve became greater at the latest follow-up. The thoracolumbar/lumbar-thoracic Cobb ratio for these 8 patients was less than that for the other patients (1.34 vs. 2.43), and their curve flexibility was worse.

CONCLUSION

Selective anterior and posterior screw instrumentation both achieved good surgical lumbar and subsequent spontaneous thoracic correction. There was no statistically significant difference between the 2 groups in lumbar correction or thoracic correction, but fusion levels were shorter in the anterior group. Patients with late thoracic curve decompensation had smaller thoracolumbar/lumbar-thoracic Cobb ratios and less preoperative flexibility than those who did not decompensate.