Should instrumented spinal fusion in nonambulatory children with neuromuscular scoliosis be extended to L5 or the pelvis?

Can postoperative Cobb and pelvic obliquity corrections be predicted using supine traction X-rays in non-ambulatory patients with cerebral palsy fused to L5? A case series study

PURPOSE

This study aimed to determine whether Cobb and pelvic obliquity corrections can be predicted using supine traction radiographs in patients with cerebral palsy (CP) who underwent posterior spinal fusion (PSF) from T2/3 to L5.

METHODS

From January 2010 to January 2020, 167 non-ambulatory patients with CP scoliosis underwent PSF using pedicle screws in two quaternary centers with a minimum of 2 years follow-up (FU). Radiological measurements and chart reviews were performed.

RESULTS

A total of 106 patients aged 15.6 ± 0.4 years were included. All patients had significant correction of the Cobb angle (MC), pelvic obliquity (PO), thoracic kyphosis (TK), and lumbar lordosis (LL) without loss of correction at the last FU (LFU). Curve flexibility was significantly correlated with Cobb correction (δMC) immediately postoperatively (p < 0.0001, r = 0.8950), followed by the amount of correction in pelvic obliquity under traction (δPOT) (p = 0.0252, r = 0.2174). For correction in PO (δPO), the most significant variable was δPOT (p < 0.0001, r = 0.7553), followed by curve flexibility (p = 0.0059, r = 0.26) and the amount of correction in Cobb under traction (p = 0.0252, r = 0.2174).

CONCLUSIONS

Cobb and PO corrections can be predicted using supine traction films for non-ambulatory CP patients treated with PSF from T2/3 to L5. The variables evaluated were interconnected, reinforcing preoperative planning for these patients. Comparative large-scale studies on patient-related clinical outcomes are required to determine whether this predicted correction is associated with improved surgical outcomes and reduced complication rates.

LEVEL OF EVIDENCE

IV.

Distal level in scoliosis surgery for non-ambulatory patients with cerebral palsy: is L5 an option? A case series study

PURPOSE

This study aimed to determine the radiographic outcomes of patients with cerebral palsy (CP) who underwent posterior spinal fusion from T2/3 to L5 at two quaternary hospitals.

METHODS

From January 2010 to January 2020, 167 non-ambulatory patients with CP scoliosis underwent posterior spinal fusion using pedicle screws from T2/3 to L5 in both centers, with a minimum of 2 years follow-up (FU). Radiological measurements and chart reviews were performed.

RESULTS

A total of 106 patients aged 15.6 ± 0.4 years were included. None of the patients was lost to FU. All patients had significant correction of the Cobb angle (MC) and pelvic obliquity (PO), thoracic kyphosis (TK), and lumbar lordosis (LL), without loss of correction at the last FU (LFU). The mean values for preoperative, immediate postoperative, and LFU were MC 93.4°, 37.5°, and 42.8°; PO 25.8°, 9.9°, and 12.7°; TK 52.2°, 44.3°, and 45°; and LL - 40.9°, - 52.4°, and - 52.9°, respectively. Higher residual PO at LFU was associated with more severe MC and PO baselines, lower implant density, and an apex located at L3.

CONCLUSIONS

CP scoliosis and PO can be corrected, and this correction is maintained over time with posterior spinal fusion using pedicle screws, with L5 as the lowest instrumented vertebra. Larger preoperative MC and PO values associated with the apex at L3 appear to be related to residual PO. Comparative large-scale studies of patient-related clinical outcomes are required to determine whether this intervention is associated with improved surgical outcomes and reduced complication rates.

LEVEL OF EVIDENCE

IV.

Distal fusion level, complications, and reoperations in individuals with cerebral palsy undergoing surgery for scoliosis

PURPOSE

To compare radiological outcome, complications and reoperations in individuals with cerebral palsy and scoliosis fused to the fifth lumbar vertebra (L5), the sacrum, or the ilia.

METHODS

208 individuals were identified in the national quality registry Swespine. Lowest level of fusion was L5 in 58, the sacrum in 92, and the ilia in 58 individuals. A subanalysis on 58 matched pairs operated to L5 or the pelvis (sacrum = 42, ilia = 16) with similar pelvic obliquity (± 5°) was performed.

RESULTS

The median (interquartile range) follow-up for the last radiograph was 1.7 (1.7) years and for reoperations 6.0 (5.9) years. Preoperatively, median Cobb angle of the major curve was 65° (23°) in the L5 group, 68° (28°) in the sacrum group, and 78° (25°) in the ilia group (p = 0.006). Preoperative median pelvic obliquity according to Maloney was 16° (19°), 21° (13°), and 27° (28°), respectively (p = 0.004). Immediate postoperative Cobb angles were 28° (18°), 28° (16°), and 32° (25°), respectively (p = 0.11). Immediate postoperative pelvic obliquity was 7° (10°), 7° (8°), and 8° (10°), respectively (p = 0.28). The median change in pelvic obliquity from the first to the last postoperative radiograph was - 5° (7°), - 3° (6°), - 3° (6°), respectively (p = 0.55). 7 (12%), 11 (12%), and 7 (12%) patients required at least one reoperation (p = 1.0), respectively. In the matched analysis, no significant differences in the radiological outcomes were found (all p ≥  0.38).

CONCLUSIONS

Maintained curve and pelvic obliquity correction with no significant difference in complication and reoperation rates were found irrespective of distal fusion level.

Distal fusion in Duchenne scoliosis: the relevance of preoperative pelvic obliquity. A case series study

PURPOSE

The aim of this study was to determine clinical and radiographic outcomes for Duchenne Muscular Dystrophy (DMD) patients who underwent posterior spinal fusion from T2/3 to L5 (without pelvic fixation), at this single centre.

METHODS

From January 2012 to January 2020, 29 consecutive DMD scoliosis patients underwent posterior spinal fusion using pedicle screws from T2/3 to L5 in a single center with a minimum of 3 years follow-up (FU). Radiologic measurements and chart review were performed.

RESULTS

Twenty nine patients aged 14 ± 1.5 years were included. No patient was lost to FU. All patients had significant correction in Cobb angle, pelvic obliquity (PO) and lumbar lordosis (LL), without loss of correction at last FU. The mean values for preoperative, immediate postoperative and last FU were CA 62o, 15o and 17o, PO: 21o, 8o and 9o; and LL 10o, -41o and -41o respectively. Correction in CA was independent of any variable analysed including implant density, rod diameter, traction, or bone density. Regarding PO, it was inversely related to age and independent of all other variables. Factors associated with postoperative complications were age and respiratory function.

CONCLUSIONS

It appears from our results that pelvic fixation might not always be required in DMD scoliosis surgery, when using pedicle screws with lowest instrumented vertebra at L5. However, larger preoperative PO values can be related with residual PO. It seems that probably related to the underlying condition, early surgery may decrease incidence of complications.

LEVEL OF EVIDENCE

IV.

The Collateral Effect of Enhanced Recovery After Surgery Protocols on Spine Patients With Neuromuscular Scoliosis

INTRODUCTION

Enhanced recovery after surgery (ERAS) protocols are often specific to a specific type of surgery without assessing the overall effect on the ward. Previous studies have demonstrated reduced length of stay (LOS) with ERAS protocols in patients with adolescent idiopathic scoliosis (AIS), although the patients are often healthy and with few or no comorbidities. In 2018, we used ERAS principles for patients undergoing AIS surgery with a subsequent 40% reduced LOS. The current study aims to assess the potential collateral effect of LOS in patients surgically treated for neuromuscular scoliosis admitted to the same ward and treated by the same staff but without a standardized ERAS protocol.

METHODS

All patients undergoing neuromuscular surgery 2 years before and after ERAS introduction (AIS patients) with a gross motor function classification score of 4 to 5 were included. LOS, intensive care stay, and postoperative complications were recorded. After discharge, all complications leading to readmission and mortality were noted with a minimum of 2 years of follow-up using a nationwide registry.

RESULTS

Forty-six patients were included; 20 pre-ERAS and 26 post-ERAS. Cross groups, there were no differences in diagnosis, preoperative curve size, pulmonary or cardiac comorbidities, weight, sex, or age. Postoperative care in the intensive care unit was unchanged between the two groups (1.2 vs 1.1; P = 0.298). When comparing LOS, we found a 41% reduction in the post-ERAS group (11 vs 6.5; P < 0.001) whereas the 90-day readmission rates were without any significant difference (45% vs 34% P = 0.22) We found no difference in the 2-year mortality in either group.

CONCLUSION

The employment of ERAS principles in a relatively uncomplicated patient group had a positive, collateral effect on more complex patients treated in the same ward. We believe that training involving the caregiving staff is equally important as pharmacological protocols.

Perioperative Risk Factors for Bleeding in Adolescents Undergoing Pedicle Screw Instrumentation for Scoliosis

Progressive scoliosis eventually leads to extensive spinal fusion surgery, which carries a risk for significant bleeding. Neuromuscular scoliosis (NMS) patients have an additional inherent risk of major perioperative bleeding. The purpose of our research was to investigate the risk factors for measured (intraoperative, drain output) and hidden blood loss related to pedicle screw instrumentation in adolescents, divided into adolescent idiopathic scoliosis (AIS) and NMS patient groups. A retrospective cohort study with prospectively collected data of consecutive AIS and NMS patients undergoing segmental pedicle screw instrumentation at a tertiary level hospital between 2009 and 2021 was conducted. In total, 199 AIS (mean age 15.8 years, 143 females) and 81 NMS patients (mean age 15.2 years, 37 females) were included in the analysis. In both groups, levels fused, increased operative time, and smaller or larger size of erythrocytes were associated with perioperative blood loss (p < 0.05 for all correlations). In AIS, male sex (p < 0.001) and the number of osteotomies correlated with more drain output. In NMS, levels fused correlated with drain output, p = 0.00180. In AIS, patients' lower preoperative MCV levels (p = 0.0391) and longer operation times, p = 0.0038, resulted into more hidden blood loss, but we did not find any significant risk factors for hidden blood loss in NMS patients.

A retrospective cohort study of bleeding characteristics and hidden blood loss after segmental pedicle screw instrumentation in neuromuscular scoliosis as compared with adolescent idiopathic scoliosis

Background

Progressive scoliosis in neuromuscular patients often requires a long instrumented spinal fusion. Previous studies have shown larger intraoperative blood loss in these patients than those with adolescent idiopathic scoliosis (AIS), but the total blood loss composed of visible and hidden blood loss has not been described in this patient population. The aim of our study was to investigate the bleeding characteristics and hidden blood loss related to spinal fusion in neuromuscular scoliosis (NMS) as compared to AIS patients.

Methods

A retrospective cohort study with prospective data collection of NMS patients undergoing segmental pedicle screw instrumentation at a university hospital between 2009 and 2021. A comprehensive statistical analysis was performed regarding intra- and postoperative blood loss compared to patient characteristics such as age and diagnosis. Hidden blood loss was estimated and compared to the total blood loss. We standardized amount of bleeding with patient weight and fusion level for further analysis. Consecutive AIS patients served as a control population. Eighty-one consecutive patients with NMS (mean age 15.2 years, 37 females) were included and their bleeding characters were compared with 199 AIS patients (mean age 15.8 years, 143 females). The primary outcome was total blood loss including intraoperative, 24-hour drain output and hidden blood loss. Secondary outcome measures included requirement for blood transfusion.

Results

Neuromuscular patients had a significantly larger total blood loss with mean values of 1914 mL in the NMS and 1357 mL in the AIS groups, respectively (p<0.001). The hidden blood loss was also significantly larger in NMS than in AIS group (566 ± 533 mL vs. 398 ±411 mL, p=0.0332). Neuromuscular scoliosis was also associated with significantly greater weight and levels of fused adjusted intraoperative bleeding (1.79 ml/kg/fused level in NMS vs. 0.87 ml/kg/fused level in AIS vs. p< 0.0001) and hidden blood loss (1.00 ml/kg/levels fused vs. 0.65 ml/kg/fused levels, p=0.053). NMS diagnosis was also a risk factor for greater hidden blood loss in multivariable analysis (p=0.0011). 24-hour drain output was similar in the NMS and AIS groups. Male gender was a risk factor for greater hidden blood loss in the NMS group (p=0.0429). Fifty-nine (73%) NMS and 27 (14%) AIS patients received allogenic red blood cell infusions perioperatively (p<0.001).

Conclusions

Hidden blood loss constitutes one-third of total blood loss in children undergoing segmental pedicle screw instrumentation for neuromuscular scoliosis. Hidden blood loss is significantly greater in the neuromuscular as compared with idiopathic scoliosis. Hidden blood loss should be considered in the perioperative management of NMS.

Pelvic fixation is not always necessary in children with cerebral palsy scoliosis treated with growth-friendly instrumentation

PURPOSE

A previous study showed that patients with neuromuscular scoliosis who underwent fusion to L5 had excellent coronal curve correction and improvement in pelvic obliquity (PO) when preoperative L5 tilt was < 15°. Our purpose was to identify indications to exclude the pelvis in children with cerebral palsy (CP) scoliosis treated with growing-friendly instrumentation.

METHODS

In a retrospective cohort study, children with CP scoliosis treated with TGR, MCGR, or VEPTR with minimum 2-year follow-up were identified from a multicenter database.

RESULTS

27 patients with distal spine anchors (DSA) and 71 patients with distal pelvic anchors (DPA) placed at the index surgery were analyzed. The DSA group had a lower pre-index PO (9° vs 16°, P = 0.0001). Most recent radiographic data were similar except the DSA patients had a smaller major curve (47° vs 58°, P = 0.038). 6 (22%) DSA patients underwent extension of the instrumentation to the pelvis (DSA-EXT), most commonly at final fusion (5 patients). DSA-EXT patients had a higher pre-index L5 tilt than patients who did not require extension (DSA-NO EXT) (19° vs 10°, P = 0.009). Sub-analysis showed a lower major curve at most recent follow-up in the DSA-EXT group compared to the DPA group (33° vs 58°, P = 0.021). The DSA-EXT group had a higher number of complications per patient compared to the DSA-NO EXT group (2.3 vs 1.1, P = 0.029).

CONCLUSION

Pre-index L5 tilt ≤ 10° and PO < 10° may be indications to exclude the pelvis in children with CP scoliosis treated with growth-friendly instrumentation. DSA may provide better long-term control of the major curve than DPA.

Is it necessary to fuse to the pelvis when correcting scoliosis in cerebral palsy?

BACKGROUND

Neuromuscular scoliosis is commonly associated with a large pelvic obliquity. Scoliosis in children with cerebral palsy is most commonly managed with posterior spinal instrumentation and fusion. While consensus is reached regarding the proximal starting point of fusion, controversy exists as to whether the distal level of spinal fusion should include the pelvis to correct the pelvic obliquity.

AIM

To assess the role of pelvic fusion in posterior spinal instrumentation and fusion, particularly it impact on pelvic obliquity correction, and to assess if the rate of complications differed as a function of pelvic fusion.

METHODS

This was a retrospective, cohort study in which we reviewed the medical records of children with cerebral palsy scoliosis treated with posterior instrumentation and fusion at a single institution. Minimum follow-up was six months. Patients were stratified into two groups: Those who were fused to the pelvis and those fused to L4/L5. The major outcomes were complications and radiographic parameters. The former were stratified into major and minor complications, and the latter consisted of preoperative and final Cobb angles, L5-S1 tilt and pelvic obliquity.

RESULTS

The study included 47 patients. The correction of the L5 tilt was 60% in patients fused to the pelvis and 67% in patients fused to L4/L5 (P = 0.22). The pelvic obliquity was corrected by 43% and 36% in each group, respectively (P = 0.12). Regarding complications, patients fused to the pelvis had more total complications as compared to the other group (63.0% vs 30%, respectively, P = 0.025). After adjusting for differences in radiographic parameters (lumbar curve, L5 tilt, and pelvic obliquity), these patients had a 79% increased chance of developing complications (Relative risk = 1.79; 95%CI: 1.011-3.41).

CONCLUSION

Including the pelvis in the distal level of fusion for cerebral palsy scoliosis places patients at an increased risk of postoperative complications. The added value that pelvic fusion offers in terms of correcting pelvic obliquity is not clear, as these patients had similar percent correction of their pelvic obliquity and L5 tilt compared to children whose fusion was stopped at L4/L5. Therefore, in a select patient population, spinal fusion can be stopped at the distal lumbar levels without adversely affecting the surgical outcomes.

[Surgical strategies in the treatment of neuromuscular scoliosis]

As part of the underlying condition, neuromuscular scoliosis occurs in early childhood. Compared to idiopathic scoliosis, neuromuscular scoliosis shows a more rapid progress of deformity, which continues even after the end of growth. This progress and the associated complications can only be prevented by surgical treatment. Depending on the patient's age and the extent of the deformity, different strategies have been established: in early childhood, so-called "growing implants" are used, while between the ages of 10 to 12, definitive treatment by reposition and fusion of the deformity is the treatment of choice. In this review, we present different surgical strategies as well as indications for surgery and discuss challenges in the treatment of these complex deformities.

When Should Instrumentation to the Pelvis be Considered in Minimally Ambulatory Adolescents With Neuromuscular Scoliosis?

INTRODUCTION

The goal of neuromuscular scoliosis (NMS) surgery is to improve sitting balance, facilitate daily care, and alleviate pain. In nonambulatory patients, where sitting balance is key, fusion to the pelvis is usually required. However, in minimally ambulatory patients, fusion to the pelvis remains controversial, and there is considerable practice variability in this patient population. The purpose of this study is to evaluate and summarize the available evidence regarding fusion constructs in minimally ambulatory patients with NMS and to provide expert opinion regarding when fusion to the pelvis should be considered.

METHODS

A search of the English literature was performed using PubMed to identify papers pertaining to patients with NMS treated with instrumented posterior spinal fusion. Papers published before 2000, case reports, and level V evidence were excluded.

RESULTS

The authors identified 8 studies for review. The majority included both nonambulatory and minimally ambulatory patients. Structured review of the literature demonstrated fusion to the pelvis may allow for greater curve and pelvic obliquity correction, but it is also associated with increased blood loss and operative time. There is no evidence that fusing to the pelvis decreases ambulatory status in minimally ambulatory patients.

CONCLUSIONS

In minimally ambulatory patients with NMS, fusion short of the pelvis may be considered in patients with adequate head control without the presence of hip subluxation or dislocation and when pelvic obliquity is <15 degrees. Fusion to the pelvis is recommended in patients who do not meet these criteria.