Spontaneous induced bone fusion in minimally invasive fusionless bipolar fixation in neuromuscular scoliosis: a computed tomography analysis

PURPOSE

Posterior spinal fusion (PSF) at skeletal maturity is still the gold standard in children with neuromuscular scoliosis (NMS) who underwent fusionless surgery. The aim of this computed tomography (CT) study was to quantify the spontaneous bone fusion at the end of a lengthening program by minimally invasive fusionless bipolar fixation (MIFBF), that could avoid PSF.

METHODS

NMS operated on with MIFBF from T1 to the pelvis and at final lengthening program were included. CT was performed at least five years postoperatively. The autofusion was classified as completely or not fused at the facets joint (on both coronal and sagittal plane, right and left side, from T1 to L5), and around the rods (axial plane, right and left side, from T5 to L5). Vertebral body heights were assessed.

RESULTS

Ten patients were included (10.7y ± 2 at initial surgery). Mean Cobb angle was 82 ± 20 preoperatively and 37 ± 13 at last follow-up. CT were performed on average 6.7y ± 1.7 after initial surgery. Mean preoperative and last follow-up thoracic vertebrae height were respectively 13.5 mm ± 1.7 and 17.4 mm ± 1.7 (p < 0.001). 93% facets joints were fused (out of 320 analyzed joints), corresponding to 15/16 vertebral levels. Ossification around the rods was observed in 6.5±2.4 levels out of 13 in the convex side, and 4.2 ± 2.2 in the concave side (p = 0.04).

CONCLUSIONS

This first computed quantitative study showed MIFBF in NMS preserved spinal growth, while it induced 93% of facet joints fusion. This could be is an additional argument when questionning the real need for PSF at skeletal maturity.

Intraoperative neuromonitoring in non-idiopathic pediatric scoliosis operated with minimally fusionless procedure: A series of 290 patients

BACKGROUND

One of the worst complications of surgery for spinal deformity is postoperative neurological deficit. Multimodal intraoperative neuromonitoring (IONM) can be used to detect impending neurological injuries. This study aimed to analyze IONM in non-idiopathic scoliosis using a minimally invasive fusionless surgical technique.

METHODS

This retrospective, single-center study was performed from 2014 to 2018. Patients with non-idiopathic scoliosis who underwent a minimally invasive fusionless procedure and had at least 2 years of follow-up were included. IONM was performed using a neurophysiological monitoring work station with somatosensory evoked potentials (SSEP) and neurogenic mixed evoked potentials (NMEP).

RESULTS

A total of 290 patients were enrolled. The mean age at surgery was 12.9±3 years. The main etiology was central nervous system (CNS) disorders (n=139, 48%). Overall, 35 alerts (11%) in the SSEP and 10 (7%) in the NMEP occurred. There were two neurological deficits with total recovery after 6 months. There were no false negatives in either SSEP or NMEP, although there was one false positive in SSEP and two false positives for NMEP in the group without signal recovery. There was no significant relationship between the incidence of SSEP or NMEP loss and age, body mass index (BMI), number of rods used, upper instrumented vertebrae (p=0.36), lower instrumented vertebrae, or type of surgery. A preoperative greater Cobb angle was associated with a significantly higher risk of NMEP loss (p=0.02). In CNS patients, a higher BMI was associated with a statistically significant risk of NMEP loss (p=0.004). The use of a traction table was associated with a higher risk of signal loss (p=0.0005).

CONCLUSION

A preoperative higher Cobb angle and degree of correction were associated with a significant risk of NMEP loss. In CNS scoliosis, a higher BMI was associated with a significant risk of NMEP loss. The use of a traction table was associated with a higher risk of signal loss.

Peripheral nerve injuries of the upper extremity in a pediatric population: outcomes and prognostic factors

Peripheral nerve injuries of the upper limb are rare in children and poorly documented. The aim of this retrospective study was to analyze long-term sensory and motor results, and to determine predictive factors for recovery after surgery. Eleven children, with a mean age at injury of 9.7 years (5-15), operated on between 2006 and 2018, were included. Sensory perception was measured on monofilament test and static 2-point discrimination test. Grip strength was measured with a dynamometer and motor strength was assessed on the Medical Research Council scale. Quality of life was assessed on QuickDASH. The injury involved the radial (n = 1), median (n = 9), or combined median and ulnar (n = 1) nerves and was repaired by primary direct suture (n = 11). The mechanism involved glass laceration (n = 10) or a road accident (n = 1). The dominant limb was involved in 7 cases. At a mean 7.7 years' follow-up, touch sensitivity was normal or slightly deficient on monofilament test. Discrimination test was normal or adequate. Strength was complete in 10 patients. Mean QuickDASH score was 5.99 (range, 0-18.18). There was no significant difference in sensory or motor recovery according to partial or complete lesion or to injury location. There was better sensory recovery in children <12 years (p < 0.05). Sensory prognosis was also better in the absence of associated lesions (p < 0.05). Sensory, motor and functional results after surgical treatment of peripheral nerve injuries of the upper limb in children were globally satisfactory. Sensory recovery was better at an early age and in the absence of associated lesions. LEVEL OF EVIDENCE: IV.

The appropriate and sequential value of standard radiograph, computed tomography and magnetic resonance imaging to characterize a bone tumor

Radiographs (XR), computed tomography (CT) or magnetic resonance imaging (MRI) are regularly analyzed to determine whether a bone lesion is benign or malignant. An online quiz was created providing 15 cases with a clinical summary, MRI, CT, and XR. After each image, participants were asked to rate the probability (0–100%) the bone tumor was malignant. Order and difficulty of the images were randomly determined. Probability statements regarding the diagnosis were actualized along the sequence of exam, to quantify how the degree of belief changed to account for evidence from those exams. 64 physicians participated and provided 154 assessments from 1 (n = 18) to 3 (n = 44) different cases. After the first image, participants favored the correct malignancy status at 70%; 80% after the second and 80% after the third one. Participants were more likely to favor the correct malignancy status when the lesion was malignant and when first confronted with XR or CT, rather than MRI, though the most predictive factor of correct diagnosis was the difficulty of the case. In conclusion, the additional information provided by successive imaging studies was moderate. XR or CT seemed more appropriate than MRI as first imaging study. Bypassing XR should be discouraged.

One-Way Self-Expanding Rod in Neuromuscular Scoliosis: Preliminary Results of a Prospective Series of 21 Patients

Fusionless techniques for the treatment of neuromuscular early-onset scoliosis (EOS) are increasingly used to preserve spinal and thoracic growth and to postpone posterior spinal fusion (PSF). These techniques have greatly improved thanks to magnetically controlled growing rods, which allow the avoidance of repeated surgery. However, the surgery-related complication rate remains high. The objective of the current study was to report the preliminary outcomes of 21 patients with neuromuscular EOS who were treated with a 1-way self-expanding rod (OWSER). This device was designed to avoid repeated surgery and preserve spinal and thoracic growth thanks to its free rod sliding.

Is daily walking distance affected in adolescent idiopathic scoliosis? An original prospective study using the pedometer on smartphones

BACKGROUND DATA

Little is known about daily walking distance levels, which accounts for approximately 80% of overall physical activity per day, in adolescents with idiopathic scoliosis (AIS).

OBJECTIVE

The aim of this study was to assess the level of walking distance in AIS treated by bracing or not, comparing this activity with that of a control group. We used an original method based on smartphone pedometers for studying walking distance in everyday life.

METHODS

Nineteen AIS patients, aged 14.1 (13-17) years, and 25 asymptomatic patients, aged 12.9 (12-14) years were included prospectively. The 19 AIS cases comprised 9 untreated individuals and 10 with ongoing night brace treatment. The mean walking distance per day as estimated by the pedometer application on smartphones for 2 months was assessed. Weekly sports activities (hours per week) were also reported.

RESULTS

During the first month, the mean walking distance was 2.58±0.65 km/day for control patients, 2.31±1.38 km/day for untreated AIS, and 3.65±0.72 km/day for AIS patients treated with a night brace. During the second month, the mean walking distance was 2.60±0.73 km/day for control patients, 2.40±1.41 km/day for untreated AIS, and 3.70±0.72 km/day for AIS patients treated with a night brace. Statistical analysis between groups showed a statistically significant difference with a higher level of daily walking distance in adolescents treated with a night brace compared with other groups.

CONCLUSION

The pedometer on smartphones is a cost-effective and friendly tool to assess adolescents' level of walking distance. Our results indicate no restriction in terms of daily walking distance between adolescents without scoliosis and those with idiopathic scoliosis.

LEVEL OF EVIDENCE

Level II.

Biomechanical cadaver study of proximal fixation in a minimally invasive bipolar construct

STUDY DESIGN

Biomechanical human cadaver study.

OBJECTIVE

To determine the three-dimensional intervertebral ranges of motion (ROMs) of intact and hook-instrumented thoracic spine specimens subjected to physiological loads, using an in vitro experimental protocol with EOS biplane radiography. Pedicle screws are commonly used in thoracic instrumentation constructs, and their biomechanical properties have been widely studied. Promising clinical results have been reported using a T1-T5 thoracic hook-claw construct for proximal rod anchoring. Instrumentation stability is a crucial factor in minimizing mechanical complications rates but had not been assessed for this construct in a biomechanical study.

METHODS

Six fresh-frozen human cadaver C6-T7 thoracic spines were studied. The first thoracic vertebrae were instrumented using two claws of supra-laminar and pedicle hooks, each fixed on two adjacent vertebrae, on either side of a single free vertebra. Quasi-static pure-moment loads up to 5 Nm were applied to each specimen before and after instrumentation, in flexion-extension, right and left bending, and axial rotation. Five steel beads impacted in each vertebra allowed 3D tracking of vertebral movements on EOS biplanar radiographs acquired after each loading step. The relative ranges of motion (ROMs) of each pair of vertebras were computed.

RESULTS

Mean ROMs with the intact specimens were 17° in flexion-extension, 27.9° in lateral bending, and 29.5° in axial rotation. Corresponding values with the instrumented specimens were 0.9°, 2.6°, and 7.3°, respectively. Instrumentation significantly (P < 0.05) decreased flexion-extension (by 92-98%), lateral bending (by 87-96%), and axial rotation (by 68-84%).

CONCLUSION

This study establishes the biomechanical stability of a double claw-hook construct in the upper thoracic spine, which may well explain the low mechanical complication rate in previous clinical studies.

LEVEL OF EVIDENCE

Not applicable, experimental cadaver study.