Five or more proximal anchors and including upper end vertebra protects against reoperation in distraction-based growing rods

Proximal foundation anchor variations and their correlation with unplanned return to the operating room (UPROR) in children with EOS treated with magnetically controlled growing rods (MCGR)

INTRODUCTION

The evolution of MCGR technique has led to modifications in the configuration of the proximal construct to decrease the incidence of implant-related complications (IRC) and revision surgeries. However, there is no data characterizing the performance of the most used configurations reducing the risk of complications.

METHODS

487 patients were identified from an international multicenter EOS database.

INCLUSION CRITERIA

EOS patients, primary dual MCGR, complete radiographs, and minimum of 2-year follow-up. 76 patients had incomplete X-rays, 5 had apical fusions, and 18 had inconclusive complications, leaving 388 patients for review. A digital spine template was created to document UIV; number of levels; number, type, and location of anchors; as well as implant configuration. First available postoperative and latest follow-up radiographs were reviewed by two senior surgeons and two spine fellows. UPROR due to IRC was defined as any change in proximal anchors between the postoperative and final follow-up radiographs.

RESULTS

The most common proximal construct configuration: UIV at T2 (50.0%) with 17.5% UPROR, followed by T3 (34.0%) with 12.1% UPROR; number of levels was three (57.1%) with 16.8% UPROR and two (26.0%) with 17.0% UPROR; number of proximal anchors was six (49.9%) with 14.1% UPROR and four (27.0%) with 18.3% UPROR. The most common anchors were all screws (42.0%) with 9.9% UPROR, and all hooks (26.4%) with 31.4% UPROR (P < 0.001). The construct with the lowest rate of UPROR was a UIV at T2, with six anchors (all screws) across three levels (42 cases), with 0% UPROR. Other construct combinations that yielded 0% UPROR rates were UIV of T3, six anchors (all screws) across three levels (25 cases), and a UIV of T3 with six anchors (screws and hooks) across three3 levels (9 cases).

CONCLUSION

Proximal anchor configuration impacts the incidence of UPROR due to IRC in MCGR. UIV at T2 and T3 compared to T4, and the use of all screws or combination of screws and hooks compared to all hooks were associated with a lower UPROR rate. The most common construct configuration was T2 UIV, three levels, six anchors, and all screws. The use of a combination of six anchors (screws or screws and hooks) across three levels with a UIV at T2 or T3 was associated with a lower UPROR rate. Additional research is needed to further evaluate the variables contributing to configuration selection and their association with IRC.

Do Rib-Based Anchors Impair Chest Wall Motion in Early Onset Scoliosis (EOS)?

Purpose

There is a concern in pediatric surgery practice that rib-based fixation may limit chest wall motion in early onset scoliosis (EOS). The purpose of this study is to address the above concern by assessing the contribution of chest wall excursion to respiration before and after surgery.

Methods

Quantitative dynamic magnetic resonance imaging (QdMRI) is performed on EOS patients (before and after surgery) and normal children in this retrospective study. QdMRI is purely an image-based approach and allows free breathing image acquisition. Tidal volume parameters for chest walls (CWtv) and hemi-diaphragms (Dtv) were analyzed on concave and convex sides of the spinal curve. EOS patients (1-14 years) and normal children (5-18 years) were enrolled, with an average interval of two years for dMRI acquisition before and after surgery.

Results

CWtv significantly increased after surgery in the global comparison including all EOS patients (p < 0.05). For main thoracic curve (MTC) EOS patients, CWtv significantly improved by 50.24% (concave side) and 35.17% (convex side) after age correction (p < 0.05) after surgery. The average ratio of Dtv to CWtv on the convex side in MTC EOS patients was not significantly different from that in normal children (p=0.78), although the concave side showed the difference to be significant.

Conclusion

Chest wall component tidal volumes in EOS patients measured via QdMRI did not decrease after rib-based surgery, suggesting that rib-based fixation does not impair chest wall motion in pediatric patients with EOS.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Magnetically Controlled Growing Rods Graduation: Lessons From a Single-center Series of 48 Patients

BACKGROUND

Magnetically controlled growing rod (MCGR) treatment for early-onset scoliosis (EOS) has become a widely utilized method of deformity control, but long-term follow-up reports are sparse. We evaluated the outcomes of a large group of consecutive pediatric patients diagnosed with EOS who were treated by MCGR to the endpoint of definitive spinal fusion in a single center. We hypothesized that lessons learned from treating a large volume of MCGR patients would lower the complication rate in comparison to what was previously reported by other studies.

METHODS

The records of 48 EOS patients with varied etiologies who were treated by MCGR between 2012 and 2022 and reached the end of treatment were analyzed retrospectively for baseline and final radiographic measurements and surgery-related complications.

RESULTS

The mean percent of improvement in the major coronal deformity was 51.7±25.0% and the mean T1 to T12 total growth was 52.9±21.9 mm. The total complication rate was 22.9% of which 12.5% required a single unplanned surgery, 6.3% required multiple unplanned surgeries, and 4% did not require any unplanned surgery.

CONCLUSION

MCGR treatment provides adequate control of EOS, enabling satisfactory growth of the thoracic spine. The complication rate in a single large volume center is moderate.

LEVEL OF EVIDENCE

IV.

Do Pedicle Screws That Terminate in the Costovertebral Joint Compromise Proximal Anchor Fixation in a Dual Growing Rod Construct?

INTRODUCTION

Growing rods (GRs) are used to treat early-onset scoliosis (EOS) recalcitrant to bracing and casting. Proximal anchor pullout, a known complication of GR constructs, can result in spinal cord injury if pedicle screw anchors are placed with a lateral-to-medial trajectory. To mitigate this risk, a more straightforward and potentially safer trajectory may result in screws that terminate within the costovertebral joint (CVJ). We asked, how often does CVJ placement occur and does this technique increase the rate of failure in GR constructs?

METHODS

We retrospectively reviewed 35 patients with EOS treated with dual GR with >2-year follow-up excluding patients with skeletal dysplasia or history of previous posterior instrumentation. Patient demographics, radiographic parameters, and implant constructs were assessed.

RESULTS

Of patients meeting the inclusion criteria, 18/35 (51%) were females with an average age of 7.96 (range: 4.0 to 15.2) years at surgery with a follow-up of 3.7 (range: 2.0 to 7.7) years. Five (14%) patients had idiopathic EOS, 5 (14%) had congenital EOS, 12 (34%) had neuromuscular EOS, 10 (29%) had syndromic scoliosis, and 3 (9%) had another etiology for EOS. Among 195 proximal pedicle screws placed, 19 (10%) terminated within the CVJ, and 13 patients (37%) had at least 1 CVJ screw. Two patients (6%) experienced unilateral proximal pullout. In both patients, the anchors on the affected side included 1 of 2 screws within the CVJ. Both patients had constructs that included 2 screws on the side that pulled out and 3 screws on the side that did not. None of the remaining 17 CVJ screws led to implant failure.

CONCLUSION

Pedicle screw placement within the CVJ is common and does not appear to significantly contribute to proximal screw pullout; however, it may contribute to unilateral implant failure in constructs employing only 2 proximal screws, where 1 of those 2 screws terminates within the CVJ. Construct modifications should be considered in this scenario.

LEVEL OF EVIDENCE

Level III.

Preoperative left shoulder elevation > 1 cm is predictive of severe postoperative shoulder imbalance in early onset idiopathic scoliosis patients treated with growth-friendly instrumentation

PURPOSE

Prior research has demonstrated the influence of preoperative shoulder elevation (SE), proximal thoracic curve magnitude, and upper instrumented vertebra (UIV) on shoulder balance after PSF for AIS. Our purpose was to evaluate the impact of these factors on shoulder balance in early onset idiopathic scoliosis (EOIS) patients treated with growth-friendly instrumentation.

METHODS

This was a multicenter retrospective review. Children with EOIS treated with dual TGR, MCGR, or VEPTR and minimum 2-year follow-up were identified. Demographics and radiographic/surgical data were collected.

RESULTS

145 patients met inclusion criteria: 74 had right SE (RSE), 49 left SE (LSE), and 22 even shoulders (EVEN) preoperatively. Mean follow-up was 5.3 years (range, 2.0-13.1 years). The LSE group had a larger pre-index mean main thoracic curve (p = 0.021) but no difference was observed between groups at the post-index or most recent timepoints. RSE patients with UIV of T2 were more likely to have balanced shoulders post-index than patients with UIV of T3 or T4 (p = 0.011). Pre-index radiographic shoulder height (RSH) was predictive of post-index shoulder imbalance ≥ 2 cm in the LSE group (p = 0.007). A ROC curve showed a cut-off of 1.0 cm for RSH. 0/16 LSE patients with pre-index RSH < 1.0 cm had post-index shoulder imbalance ≥ 2 cm compared to 8/28 (29%) patients with pre-index RSH > 1.0 cm (p = 0.006).

CONCLUSION

Preoperative LSE > 1.0 cm is predictive of shoulder imbalance ≥ 2 cm after insertion of TGR, MCGR, or VEPTR in children with EOIS. In patients with preoperative RSE, UIV of T2 resulted in a higher likelihood of balanced shoulders postoperatively.

Benefits of fixing 3 proximal vertebral bodies vs. 2 in the treatment of early-onset scoliosis with growing rods

Additional proximal fixation for growing rods in early-onset scoliosis (EOS) may offer a more effective and safer option for severe scoliosis patients with hyper-kyphosis. Here, we compared the outcomes of EOS patients treated with growing rods in which 6 proximal anchor points on 3 vertebrae were used vs. 4 proximal anchor points on 2 vertebrae. The records of patients with EOS treated surgically from January 2016 to December 2017 were retrospectively reviewed. In the Proximal 4 group, 2 vertebral bodies were anchored proximally with 4 anchor points; in the Proximal 6 group, 3 vertebral bodies were anchored proximally with 6 anchor points. Forty-two patients (mean age 5.11 ± 1.93 years) were included; 22 Proximal 4 group, 20 Proximal 6 group. Mean follow-up was 40.86 ± 13.49 months. The decrease in main curve Cobb angle postoperatively was significantly greater in the Proximal 6 group (33.22° vs. 19.08°) ( P < 0.05). Cobb thoracic kyphosis (TK) was significantly decreased postoperatively in the Proximal 6 group (mean 20.70°); no significant decrease occurred in the Proximal 4 group. The main curve Cobb angle decrease at last follow-up was significantly greater in the Proximal 6 group (37.84° vs. 24.23°) ( P < 0.05). Cobb TK was significantly decreased at last follow-up in the Proximal 6 group (mean 25.17°, P < 0.05); no significant decrease occurred in the Proximal 4 group. Instrument complications were lower in the Proximal 6 group (15.00% vs. 45.45%) ( P < 0.05). No proximal junctional kyphosis was noted. Fixing 3 proximal vertebral bodies with 6 anchors improves radiographic outcomes of EOS treated with growing rods, and has a lower rate of screw pull-out.

Early outcomes of growth friendly instrumentation in children with Williams syndrome

PURPOSE

Although scoliosis and kyphosis have been associated with Williams Syndrome (WS), no previous literature has reported on surgical treatment for early onset scoliosis (EOS) in WS. The aim of this case series is to report on the outcomes of spine deformity surgery in patients with EOS and WS and any perioperative anesthetic or cardiovascular complications.

METHODS

One multicenter database was queried for all patients with WS who underwent growth-friendly (GF) treatment before age 12 between 2000 and 2017. Demographics, surgical, and growth-friendly data were queried. Radiographs were measured for curve magnitude, T1-T12 length, and T1-S1 length.

RESULTS

Seven patients were analyzed (3 males, 4 females). Patients were at a median age of 2.8 years at initial surgery with median follow-up 3.6 years (range 2.0-12 years) after index surgery. The initial surgical treatments were as follows: 2 traditional growing rods (TGR), 2 magnetically controlled growing rods (MCGR), and 3 vertical expandable prosthetic titanium ribs (VEPTR). The median duration of growth-friendly treatment was 5.0 years (range, 2.6-10.4 years) with a median number of 9 device lengthenings. The median improvement in coronal curve magnitude from preoperative to most recent follow-up was 19° (range, 54°-9°). Three patients have completed GF treatment: one underwent definitive fusion, and two are under observation with apparent spontaneous fusion and retain the original GF implants. No peri-operative anesthetic or cardiovascular complications occurred.

CONCLUSIONS

Few studies have reported on surgical outcomes in WS patients with EOS. In this case series, 6/7 patients experienced curve improvement with growth-friendly spine instrumentation. This study suggests that growth-friendly instrumentation for severe EOS in WS can be used for control of spinal deformity while allowing for further growth. Associated complications were typical of distraction-based EOS surgical treatment. There were 62 total procedures with general anesthesia, but no perioperative cardiac complications occurred.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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