Rigid Instrumentation for Neuromuscular Scoliosis Improves Deformity Correction Without Increasing Complications

Pedicle screw accuracy placed with assistance of machine vision technology in patients with neuromuscular scoliosis

INTRODUCTION

Pedicle screws are the primary method of vertebral fixation in scoliosis surgery, but there are lingering concerns over potential malposition. The rates of pedicle screw malposition in pediatric spine surgery vary from 10% to 21%. Malpositioned screws can lead to potentially catastrophic neurological, vascular, and visceral complications. Pedicle screw positioning in patients with neuromuscular scoliosis is challenging due to a combination of large curves, complex pelvic anatomy, and osteopenia. This study aimed to determine the rate of pedicle screw malposition, associated complications, and subsequent revision from screws placed with the assistance of machine vision navigation technology in patients with neuromuscular scoliosis undergoing posterior instrumentation and fusion.

METHOD

A retrospective analysis of the records of patients with neuromuscular scoliosis who underwent thoracolumbar pedicle screw insertion with the assistance of machine-vision image guidance navigation was performed. Screws were inserted by either a staff surgeon, orthopaedic fellow, or orthopaedic resident. Post-operative ultra-low dose CT scans were used to assess pedicle screw accuracy. The Gertzbein classification was used to grade any pedicle breaches (grade 0, no breach; grade 1, <2 mm; grade 2, 2-4 mm; grade 3, >4 mm). A screw was deemed accurate if no breach was identified (grade 0).

RESULTS

25 patients were included in the analysis, with a mean age of 13.6 years (range 11 to 18 years; 13/25 (52.0%) were female. The average pre-operative supine Cobb angle was 90.0 degrees (48-120 degrees). A total of 687 screws from 25 patients were analyzed (402 thoracic, 241 lumbosacral, 44 S2 alar-iliac (S2AI) screws). Surgical trainees (fellows and orthopaedic residents) inserted 46.6% (320/687) of screws with 98.8% (4/320) accuracy. The overall accuracy of pedicle screw insertion was 98.0% (Grade 0, no breach). All 13 breaches that occurred in the thoracic and lumbar screws were Grade 1. Of the 44 S2AI screws placed, one screw had a Grade 3 breach (2.3%) noted on intra-operative radiographs following rod placement and correction. This screw was subsequently revised. None of the breaches resulted in neuromonitoring changes, vessel, or visceral injuries.

CONCLUSION

Machine vision navigation technology combined with careful free-hand pedicle screw insertion techniques demonstrated high levels of pedicle screw insertion accuracy, even in patients with challenging anatomy.

Modification to the placement of the navigation reference frame in posterior corrective fusion of spinal deformity with myelomeningocele: a series of 6 cases

To show a modified placement of the navigation reference frame in posterior corrective fusion of spinal deformity with myelomeningocele. This was a retrospective, single-surgeon case series, and IRB-approved study. Six consecutive patients (one male and five females) who were diagnosed with spinal deformity with myelomeningocele underwent posterior corrective fusion surgery from the upper thoracic spine to the pelvis with preoperative computed tomography navigation (pCTN). At the level of the spina bifida, where posterior elements such as the spinous process were missing, the reference frame of the pCTN was placed on the flipped lamina or pedicles, and a pedicle screw (PS) or iliac screw (IS) was inserted. Screw deviation was investigated by using postoperative CT. A total of 55 screws were placed at the spina bifida level and pelvis. Of these, 12 ISs were placed on each side in each case. The screws placed using the pCTN were not reinserted or removed intraoperatively or postoperatively. However, only one PS was found to have perforated the spinal canal on postoperative CT but was left in place because it caused no neurological problem. By modifying the placement of the reference frame, such as placing it on the flipped lamina or pedicles, pCTN could be used even at the levels of the spina bifida, where the posterior elements are missing, to accurately place PSs and various types of ISs.

Growing rods in meningomyelocele lead to increased risk for complications in comparison with fusion; a retrospective study of 30 patients treated for at the University Hospital of Uppsala

PURPOSE

To compare the complication rates of two different types of posterior instrumentation in patients with MMC, namely, definitive fusion and fusionless surgery (growing rods).

METHODS

Single-center retrospective study of 30 MMC patients that underwent posterior instrumentation for deformity (scoliosis and/or kyphosis) treatment from 2008 until 2020. The patients were grouped based on whether they received definitive fusion or a growth-accommodating system, whether they had a complication that led to early surgery, osteotomy or non-osteotomy. Number of major operations, Cobb angle correction and perioperative blood loss were the outcomes.

RESULTS

18 patients received a growing system and 12 were fused at index surgery. The growing system group underwent a mean of 2.38 (± 1.03) surgeries versus 1.91 (± 2.27) in the fusion group, p = 0.01. If an early revision was necessitated due to a complication, then the number of major surgeries per patient was 3.37 (± 2.44) versus 1.77 (± 0.97) in the group that did not undergo an early revision, p = 0.01. Four patients developed a superficial and six a deep wound infection, while loosening/breakage occurred in 10 patients. The Cobb angle was improved from a mean of 69 to 22 degrees postoperatively. Osteotomy did not lead to an increase in perioperative blood loss or number of major operations.

CONCLUSION

Growing systems had more major operations in comparison with fusion surgery and early revision surgery led to higher numbers of major operations per patient; these differences were statistically significant. Definitive fusion at index surgery might be the better option in some MMC patients with a high-risk profile.

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.

Ilio-sacral screw pelvic fixation when correcting spinal deformities with or without pelvic obliquity: our experience over 40 years

Ilio-sacral screw fixation for treatment of spinal deformities with pelvic obliquity was used from more than 40 years in our department of pediatric orthopedics. Despite trying all the other systems published in the literature, the authors came back to iliosacral screw to address the pelvic fixation. Keeping the same anatomical and biomechanical principles, with no damage of the SI joint, they improve the technology over time, to allow an easy use. The fear about the precise insertion necessary to prevent any root irritation is now greatly reduced thanks to the modern navigation. The history of the establishment and the advantages of this technique are explained based on more than 250 cumulative cases with an excellent correction of the pelvic obliquity, without any case of complete pull out of the ilio-sacral screw. A very low rate of nonunion thanks to the 3D adaptation of the balance in erect standing or sitting posture of the patient, thanks to the motion of the intact SI joint, and the small sagittal motion existing in the linkage screw/connector. All this comparing favorably to the other techniques published in the current literature.

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

STUDY DESIGN

A retrospective analysis of a prospective registry.

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

2.

Pedicle Subtraction Osteotomy Versus Multiple Posterior Column Osteotomies in Severe and Rigid Neuromuscular Scoliosis

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

The aim of this study is to compare the safety and efficacy of the apical pedicle subtraction osteotomy (PSO) technique with multiple posterior column osteotomies (PCOs) in nonambulatory patients with severe, rigid neuromuscular scoliosis.

SUMMARY OF BACKGROUND DATA

Neuromuscular scoliosis frequently causes intolerance to sitting due to pelvic obliquity, trunk decompensation, and associated back and rib impingement pain which diminish the patient's functional capacity. In the case of rigid curves, spinal osteotomy techniques are occasionally required for effective correction.

METHODS

We retrospectively reviewed our patients with severe and rigid neuromuscular scoliosis with associated pelvic obliquity who were treated with posterior instrumented fusion extending to pelvis with more than 1-year postoperative follow-up. We compared radiological and clinical results of PSO and multiple PCO techniques in severe rigid neuromuscular scoliosis with pelvic obliquity of more than 15° in traction radiograph under general anesthesia. Hospital records were also reviewed for operative time, intraoperative blood loss, amount of blood transfusion, duration of hospital stay, and complications.

RESULTS

There were 12 patients in the PSO group and 10 patients in the PCO group. There was no significant difference between groups in terms of major curve magnitude, sagittal parameters or pelvic obliquity. Although not statistically significant, PSO technique did trend toward better scoliosis correction (post-op Cobb angle 56.1° vs. 66.7° [P = 0.415]). PSO technique provided a significantly better correction in pelvic obliquity (59% vs. 84%) (P = 0.001). There was no significant difference in average intraoperative blood loss, transfusion, and operative times including anesthesia time, hospital stay, or complications.

CONCLUSION

PSO may be an option in correction of severe and rigid neuromuscular scoliosis. It provides better correction of pelvic obliquity without increasing operative time, need for transfusion, or duration of hospitalization as compared to multiple apical PCO technique. Traction radiograph under general anesthesia is a valuable tool in surgical decision making.

LEVEL OF EVIDENCE

4.

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

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

Outcomes and complications of S2 alar iliac fixation technique in patients with neuromuscular scoliosis: experience in a third level pediatric hospital

BACKGROUND

Multiple techniques are utilized for distal fixation in patients with neuromuscular scoliosis. Although there is evidence of benefit with S2 alar iliac (S2AI) fixation, this remains controversial. The objective of this study is to evaluate the radiological outcomes and complications associated with this surgical technique in a pediatric population.

METHODS

An observational retrospective case series study was performed. All pediatric patients between January 2011 and February 2014 diagnosed with neuromuscular scoliosis associated with pelvic obliquity, which required surgery with fixation unto S2AI, were included. Clinical, radiological findings, and adverse events were presented with measures of central tendency. Comparison of deformity correction was carried out using a non-parametric analysis for related samples (Wilcoxon signed-rank test). Significance was set at P<0.05.

RESULTS

A total of 31 patients diagnosed with neuromuscular scoliosis that met inclusion criteria were analyzed. The leading cause of neuromuscular scoliosis in 23 (74.2%) patients was spastic cerebral palsy (CP). The correction of pelvic obliquity in the immediate postoperative period was of 76%, which is statistically significant. The extent of correction that patients maintained at the end of the follow-up was analyzed, and it was found that there were no significant differences in this magnitude, compared with the immediate postoperative pelvic obliquity. The mean follow-up time was 9±7 months. Regarding postoperative adverse events, occurred in 64.5% of patients, the most common outcome was pneumonia (14.8%). The overall rate of complications related to instrumentation was low (1.9%), which corresponds to one patient with an intra-articular screw in the left hip that required repositioning.

CONCLUSIONS

S2AI fixation for the treatment of neuromuscular scoliosis is a safe alternative, in which the onset of adverse events is related to the comorbidities of patients instead of the surgical procedure itself. An approximate correction of 76% of pelvic obliquity is maintained during the follow-up.

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

AIM

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

METHOD

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

RESULTS

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

INTERPRETATION

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