Hybrid fixation with sublaminar polyester bands in the treatment of neuromuscular scoliosis: a comparative analysis

Autonomous lumbar spine pedicle screw planning using machine learning: A validation study

Introduction:

Several techniques for pedicle screw placement have been described including freehand techniques, fluoroscopy assisted, computed tomography (CT) guidance, and robotics. Image-guided surgery offers the potential to combine the benefits of CT guidance without the added radiation. This study investigated the ability of a neural network to place lumbar pedicle screws with the correct length, diameter, and angulation autonomously within radiographs without the need for human involvement.

Materials and Methods:

The neural network was trained using a machine learning process. The method combines the previously reported autonomous spine segmentation solution with a landmark localization solution. The pedicle screw placement was evaluated using the Zdichavsky, Ravi, and Gertzbein grading systems.

Results:

In total, the program placed 208 pedicle screws between the L1 and S1 spinal levels. Of the 208 placed pedicle screws, 208 (100%) had a Zdichavsky Score 1A, 206 (99.0%) of all screws were Ravi Grade 1, and Gertzbein Grade A indicating no breech. The final two screws (1.0%) had a Ravi score of 2 (<2 mm breech) and a Gertzbein grade of B (<2 mm breech).

Conclusion:

The results of this experiment can be combined with an image-guided platform to provide an efficient and highly effective method of placing pedicle screws during spinal stabilization surgery.

Hybrid versus total sublaminar wires in patients with spinal muscular atrophy undergoing scoliosis surgery

Background

Early versions of spinal muscular atrophy (SMA) scoliosis correction surgery often involved sublaminar devices. Recently, the utilization of pedicle screws has gained much popularity. Pedicle screws are generally believed to provide additional deformity correction, but pedicle size and rotational deformity limit their application in the thoracic spine, resulting in a hybrid construct involving pedicle screws and sublaminar wire. Studies of the efficacy of hybrid instrumentation in SMA scoliosis are often limited by the scarcity of the disease itself. In this study, we aimed to compare the surgical outcomes between hybrid constructs involving pedicle screws and sublaminar wire and sublaminar wire alone in patients with SMA scoliosis.

Methods

We retrospectively reviewed the clinical records and radiographic assessments of patients with SMA scoliosis who underwent corrective surgery between 1993 and 2017. The radiographic assessments included deformity correction and progressive changes in the major curve angle, pelvic tilt (PT) and coronal balance (CB). The correction of deformities was observed postoperatively and at the patient’s 2-year follow-up to test the efficacy of each type of construct.

Results

Thirty-three patients were included in this study. There were 14 and 19 patients in the wiring and hybrid construct groups, respectively. The hybrid construct group demonstrated a higher major curve angle correction (50.5° ± 11.2° vs. 36.4° ± 8.4°, p < 0.001), a higher apical vertebral rotation correction (10.6° ± 3.9° vs. 4.8° ± 2.6°, p < 0.001), and a reduced progression of the major curve angle at the 2-year follow-up (5.1° ± 2.9° vs. 8.7° ± 4.8°, p < 0.001). A moderate correlation was observed between the magnitude of correction of the apical vertebral rotation angle and the major curve (r = 0.528, p = 0.002).

Conclusion

This study demonstrated that hybrid instrumentation can provide a greater magnitude of correction in major curve and apical rotation as well as less major curve progression than sublaminar wire instrumentation alone in patients with SMA scoliosis. Level of evidence III

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04737-0.

Comparison of Pedicle Screws Versus Hybrid Fixation With Sublaminar Polyester Bands in the Treatment of Neuromuscular Scoliosis

BACKGROUND

The choice of implants in neuromuscular scoliosis (NMS) surgery remains controversial. Sublaminar polyester bands (SPBs) seem to be a promising alternative implant. The purpose of current study was to compare clinical and radiologic results of posterior instrumentation and fusion using hybrid constructs versus only pedicle screws for NMS treatment.

METHODS

In 24 patients, pedicle screws were used in all segments, and 18 patients underwent hybrid fixation. Cobb angle, thoracic kyphosis, lumbar lordosis angles, and pelvic obliquity were compared before and immediately after surgery, at the last follow-up radiographs. Demographic, clinical information, duration of surgery, estimated blood loss (EBL), blood transfusion, and complications were compared between groups. Additionally, patients were assessed for pain with visual analog scale (VAS) and quality of life with Short Form 36 (SF-36) and the Oswestry scale.

RESULTS

Baseline characteristics of patients were similar except for EBL (P = 0.002) and follow-up duration (P = 0.004). The mean curve correction was 58.1% in the hybrid group, and 67.6% in the screw group (P = 0.07), and loss of correction was significantly lower in hybrid group (2.72° ± 1.48° vs. 3.66° ± 1.52°, P = 0.049). Functional scores at final follow-up were equal in both groups (VAS P = 0.865, Oswestry P = 0.097, SF-36 Physical P = 0.358, SF-36 Mental P = 0.145).

CONCLUSIONS

SPBs might be a better fixation alternative at the apex of rigid spinal deformity in NMS. The deformity can be corrected with less blood loss and at a similar rate of correction, with similar rate complications compared with pedicle screws.

Novel Use of Subcostal Polyethylene Bands to Manage Tumor-Related Scoliosis Requiring Serial Imaging: A Case Report

CASE

A 16-year-old male patient with severe kyphoscoliosis, paraplegia, and neurogenic bowel/bladder caused by a juvenile pilocytic astrocytoma was treated surgically using a hybrid fusion construct with polyethylene bands after neoplasm resection. Owing to the necessity of serial postoperative magnetic resonance imaging studies to evaluate the recurrence of pathology and known effect of metal artifact from spinal instrumentation, preservation of radiographic resolution was critical.

CONCLUSION

We describe the novel utility of polyethylene bands placed around the ribs as a safe and effective form of hybrid construct for reducing radiographic metal artifact in spinal deformity cases requiring serial imaging.

Sublaminar polyester bands for the correction of idiopathic and neuromuscular scoliosis

Recent literature suggests that sublaminar bands (SB) can provide good coronal plane correction, comparable to pedicle screw constructs, as well as good correction in the sagittal plane, even in patients with preoperative hypokyphosis; comparable results have been reported in patients with adolescent idiopathic scoliosis (AIS) and in patients with neuromuscular scoliosis (NMS). Two types of SB constructs can be performed: the band-only construct, indicated for non-ambulatory patients with NMS, and the hybrid construct indicted for ambulatory patients with NMS and for patients with AIS. SB are made of polyester or acrylic material and do provide a safe alternative to sublaminar Luque-type wires (stainless steel) as well as an increased contact area between SB and bone allowing higher corrective forces and reduced laminar fracture risk; the use of SB is not associated with increased risk of neurological injury nor with an increased risk of deep postoperative infection. SB used in a hybrid or in a band-only construct in patients with AIS and NMS, appear to be safe in a trained surgeon hands and can achieve well-balanced spine in both coronal and sagittal planes. This article aimed to provide a review of how SB can restore normal frontal and sagittal spine alignment in patients with AIS and NMS.

Sublaminar polyester band fixation construct in the treatment of neuromuscular scoliosis

PURPOSE

Multiple fixation techniques exist for treating progressive neuromuscular scoliosis including pedicle screws, sublaminar bands/wires, hooks or a combination of instruments. Most sublaminar band constructs are supplemented with pedicle screws, hooks and/or sublaminar wires particularly at the top of the construct. There are no studies to date that describe an all/predominant sublaminar band construct. The purpose of this study was to investigate the outcomes of a sublaminar polyester band construct to treat neuromuscular scoliosis.

METHODS

A retrospective review was conducted of 32 cases of neuromuscular scoliosis treated with posterior spinal fusion using a sublaminar band construct between 2013 and 2016 by a single surgeon at a single centre. Preoperative, immediate postoperative and two-year follow-up radiographs and clinical records were reviewed. Sagittal, coronal and pelvic obliquity correction was measured. Blood loss, length of surgery and complications were recorded.

RESULTS

In all, 29 patients were included. Mean postoperative coronal plane correction was 57% (0% to 92%) and maintained at two-year follow-up. Mean sagittal balance was 2.3 cm (-2.5 to 6.4). Mean lumbar lordosis angle decreased by 7° (44° to 37°). Mean thoracic kyphosis angle increased by 9° (23° to 32°). Mean pelvic obliquity decreased by 50% (from 15° to 7°). There were four major complications (14%) and eight minor complications (21%). Mean blood loss was 1304 cc (250 cc to 2450 cc).

CONCLUSION

Sublaminar polyester band fixation constructs provide a viable option in correction of deformity in patients with neuromuscular scoliosis with comparable outcomes with what is reported with other constructs.

LEVEL OF EVIDENCE

V.

How to Optimize Axial Correction Without Altering Thoracic Sagittal Alignment in Hybrid Constructs With Sublaminar Bands: Description of the "Frame" Technique

STUDY DESIGN

Retrospective monocentric database study.

OBJECTIVES

To describe the "frame" reduction technique and report the 3D quantitative analysis of postoperative corrections in a consecutive series of thoracic adolescent idiopathic scoliosis (AIS) patients.

SUMMARY OF BACKGROUND DATA

Posteromedial translation technique using sublaminar bands have been proved to be efficient and safe for 3D correction of the deformity and overall cosmetic aspect of the trunk. However, the ability to correct the axial plane may tend to rotate the vertebra clockwise instead of counterclockwise, thus increasing apical vertebra axial rotation (AVR) and the rib hump. A technical improvement was developed to emphasize axial correction.

METHODS

60 thoracic AIS patients consecutively operated by posteromedial translation using the "frame" reduction technique were included with a minimum 2-year follow-up. Precontoured rods were connected with fixed transverse connectors according to a personalized preoperative planning. Rods were first inserted distally in the pedicle screws to achieve lumbar correction, and then in the upper anchors, and finally sublaminar bands were connected to their corresponding rods to progressively bring the concave lamina to the concave rod to correct the thoracic deformity. Sagittal and coronal 3D measures were performed preoperatively and at the latest follow-up using SterEOS (EOS Imaging, Paris, France) to assess the efficiency of the technique.

RESULTS

The distance from the center of the apical vertebra to the reference axis in the frontal plane was reduced from 4.7 to 1.1 cm, traducing the efficient medial translation of the spine during correction. T1-T12 kyphosis significantly increased after surgery (28°-35°). 3D location of the upper instrumented vertebra (UIV) was not affected. The apical rotation was significantly reduced after surgery (19°-11°), and the AVR correction rate averaged 42.2%.

CONCLUSION

The "frame" technique is an innovative way of using polyester bands, optimizing axial correction while respecting sagittal alignment.

LEVEL OF EVIDENCE

Level IV.

Sublaminar banding as an adjunct to pedicle screw-rod constructs: a review and technical note on novel hybrid constructs in spinal deformity surgery

Sublaminar implants that encircle cortical bone are well-established adjuncts to pedicle screw-rod constructs in pediatric deformity surgery. Sublaminar bands (SLBs) in particular carry the advantage of relatively greater bone contact surface area as compared to wires and pullout loads that are independent of bone mineral density, in contrast to pedicle screws. Whereas the relevant technical considerations have been reported for pediatric deformity correction, an understanding of the relative procedural specifics of these techniques is missing for adult spinal deformity (ASD), despite several case series that have used distinct posterior tethering techniques for proximal junctional kyphosis prevention. In this paper, the authors summarize the relevant literature and describe a novel technique wherein bilateral tensioned SLBs are introduced at the nonfused proximal junctional level of long-segment ASD constructs.

Safety and efficacy of sublaminar bands and Ponte osteotomies in rigid deformity: preliminary results in a prospective series of 20 neuromuscular scoliosis patients

This prospective cohort study investigated radiographic outcomes and complications over time in patients with rigid neuromuscular scoliosis treated with sublaminar bands and Ponte osteotomies. Twenty consecutive patients with neuromuscular scoliosis were treated with sublaminar bands in addition to Ponte osteotomies at and around the apex of the deformity and prospectively included. All curves were rigid, with less than 30% reduction on preoperative bending films. Cobb angle, pelvic obliquity, and shoulder obliquity were significantly corrected (P<0.01). Normal thoracic kyphosis was achieved for 85% of patients at the last follow-up. No intraoperative complications were observed. The association between Ponte osteotomies and sublaminar bands appears to be efficient for the management of rigid neuromuscular deformities in children and adolescents. No death and no permanent neurological impairment, as well as no sublaminar bands associated events were recorded.