Management of severe spinal deformity: scoliosis and kyphosis

MRI Screening in Operative Scheuermann Kyphosis: Is it Necessary?

STUDY DESIGN

Patients with preoperative spine magnetic resonance imaging (MRI) studies from a prospective multicenter study of operative adolescent Scheuermann kyphosis (SK).

OBJECTIVES

To investigate the usefulness of MRI screening in operative planning for SK surgeries.

SUMMARY OF BACKGROUND DATA

Neural axis abnormalities in operative SK have not been previously studied with MRI screening, despite its use.

METHODS

One orthopedic surgeon and two radiologists evaluated all images retrospectively. Radiographs were evaluated for kyphosis apex and magnitude. MRIs were evaluated for spinal cord abnormalities, epidural lipomatosis, location and number of vertebral wedging, Schmorl nodes and posterior disc herniations, frequency of spondylolysis, etc. The relationship of these pathologies to the kyphosis apex was explored. This group was compared to a surgical SK group without preoperative MRIs.

RESULTS

Eighty-six patients with MRIs, mean age 16.3 years, 64% male, and a mean preoperative kyphosis of 75.9° were evaluated. There were 17 spinal cord abnormalities. Low-lying conus was found in 2 patients, and syrinx in 15 (no Chiari malformations). Epidural lipomatosis was found in 49 patients, average of 5.7 levels. Anterior vertebral wedging occurred in all (mean 4.7 levels). Posterior disc herniations averaged 5.2 levels/patient and 1.8 levels caudad to the apex. Spondylolysis was reported in 8.1%. Four cases (4.7%) had the operative plan changed as a result of the preoperative MRI: two due to neural compression, one due to disc herniation and one due to a spinal cord draped over the apex. Thirty-one patients did not receive an MRI; there were no significant differences between the two groups. The rate of postoperative neurologic change was 3.5% in the MRI group and 3.2% in the no-MRI group.

CONCLUSIONS

Based on 4.7% of cases requiring a change in the operative plan as a result of preoperative MRI, the authors recommend considering performing screening MRI in operative SK patients.

Canadian Consensus for the Prevention of Blood Loss in Spine Surgery

STUDY DESIGN

Cross-sectional, modified Delphi approach.

OBJECTIVE

The primary objective of this study was to identify patients at risk of increased perioperative blood loss according to the opinion of expert spine surgeons across Canada. The secondary objective was to obtain information about the experts' approach on how to minimize significant blood loss perioperatively.

SUMMARY OF BACKGROUND DATA

Significant blood loss in major spinal surgeries has been associated with increased intra- and perioperative complications and costs. The current available evidence regarding risk factors and preventive measures for increased blood loss remains incomplete.

METHODS

A modified Delphi approach was employed to generate consensus opinion on the risk factors and preventive measures for significant blood loss in major spinal surgeries. Twenty-five spine surgeons in Canada participated in this study.

RESULTS

Among various factors, surgery for the treatment of spine tumors and prolonged operative time of greater than 5 hours were found to be the most important predictive factors for blood loss in spine surgery. On the other hand, appropriate surgical hemostasis was considered the most effective measure for the prevention of blood loss in these surgeries.

CONCLUSION

We recommend the reduction of blood loss by means of meticulous hemostasis and shorter operative time when it is safe and possible. This might result in better treatment outcomes. It would also lead to a reduction in costs associated with major spine surgeries and would ultimately lead to greater value-based spine care.

LEVEL OF EVIDENCE

4.

Halo-gravity traction in the treatment of severe spinal deformity: a systematic review and meta-analysis

PURPOSE

Halo-gravity traction has been reported to successfully assist in managing severe spinal deformity. This is a systematic review of all studies on halo-gravity traction in the treatment of spinal deformity to provide information for clinical practice.

METHODS

A comprehensive search was conducted for articles on halo-gravity traction in the treatment of spinal deformity according to the PRISMA guidelines. Appropriate studies would be included and analyzed. Preoperative correction rate of spinal deformity, change of pulmonary function and prevalence of complications were the main measurements.

RESULTS

Sixteen studies, a total of 351 patients, were included in this review. Generally, the initial Cobb angle was 101.1° in the coronal plane and 80.5° in the sagittal plane, and it was corrected to 49.4° and 56.0° after final spinal fusion. The preoperative correction due to traction alone was 24.1 and 19.3%, respectively. With traction, the flexibility improved 6.1% but postoperatively the patients did not have better correction. Less aggressive procedures and improved pulmonary function were observed in patients with traction. The prevalence of traction-related complications was 22% and three cases of neurologic complication related to traction were noted. The prevalence of total complications related to surgery was 32% and that of neurologic complications was 1%.

CONCLUSION

Partial correction could be achieved preoperatively with halo-gravity traction, and it may help decrease aggressive procedures, improve preoperative pulmonary function, and reduce neurologic complications. However, traction could not increase preoperative flexibility or final correction. Traction-related complications, although usually not severe, were not rare.

Staged Anterior Release and Posterior Instrumentation in Correction of Severe Rigid Scoliosis (Cobb Angle >100 Degrees)

PURPOSE

Severe rigid curves present a big challenge to the treating spine surgeon. We evaluated the outcome of staged anterior release and posterior instrumentation for rigid scoliosis.

METHODS

Twenty-one patients with an average age of 14.4 years (range 11-17) having a rounded severe rigid scoliosis (Cobb angle >100 degrees) underwent surgical correction. Six patients had congenital scoliosis, 13 idiopathic scoliosis, and 2 syndromic. All patients underwent anterior release in Stage I with one or more Ponte osteotomies and in Stage II with all pedicle screw instrumentation, and 13 of the patients underwent an asymmetric pedicle subtraction osteotomy at the apex. Patients were assessed for deformity correction, operative time, blood loss, and any complications.

RESULTS

The preoperative Cobb angle of 116.6 degrees (range 101-124 degrees) improved to 74.0 degrees (range 54-86 degrees) after anterior release: 29.4% correction and the final postoperation Cobb angle after posterior instrumentation was 26.5 degrees (range 22-32 degrees), with final 76% correction. The average blood loss in anterior release was 585.95 mL (range 400-980 mL; % estimated blood volume = 19.5%), whereas the mean operative time was 223 minutes (165-315 minutes). One patient had prolonged chest drain and two, basal atelectasis following anterior release. The mean operative time for the posterior procedure was 340 minutes (range 280-420 minutes) and average blood loss was 2,066 mL (range 1,200-3,200 mL). The mean apical axial rotation of 56 degrees (range 26-79 degrees) improved to 28 degrees (range 9-42 degrees) (p < .05). There was loss of motor evoked potential signal in one and hook pullout, superficial infection, and local skin necrosis one case each.

CONCLUSION

The staged approach to the management of severe, rigid scoliosis helps get an excellent correction. Anterior release loosens up the rigid apex and provides with nearly 30% correction so that the extent of the osteotomies in the second stage from the back is substantially reduced, allowing for a final good correction.

Shilla Growth Guidance for Early-Onset Scoliosis: Results After a Minimum of Five Years of Follow-up

BACKGROUND

The Shilla growth guidance technique was developed to allow growth during treatment of a child's spinal deformity without requiring repeated surgery for lengthening procedures. Dual stainless-steel rods are fixed posteriorly to the corrected apex via pedicle screws with a limited fusion at the apex and are combined with sliding pedicle screws to allow vertebral growth in a cephalad and caudad direction.

METHODS

A retrospective study of the original forty patients treated with the Shilla method for a severe deformity of a growing spine was performed to determine the efficacy of the procedure.

RESULTS

The etiology of the spinal deformity in the forty patients was idiopathic in nine, congenital in one, neuromuscular in sixteen, and syndromic in fourteen. The average age at the index surgery was six years and eleven months, and the average duration of follow-up for the thirty-three eligible patients was seven years (range, four years and nine months to ten years and nine months). The curves averaged 69° (range, 40° to 115°) preoperatively and 38.4° (range, 16° to 74°) at the time of the most recent follow-up or prior to definitive spinal instrumentation and fusion. Complications included secondary infections (six patients), alignment issues (eight patients), and implant-related problems (twenty-four patients), with some patients experiencing more than one complication.

CONCLUSIONS

The Shilla growth guidance technique is a method of scoliosis treatment that allows spinal growth while controlling the deformity without scheduled repeated surgical procedures. The complication rate is high (73%) but acceptable, and children with a wide variety of diagnoses can be safely treated with the Shilla procedure.

Perioperative Major Non-neurological Complications in 105 Patients Undergoing Posterior Vertebral Column Resection Procedures for Severe Rigid Deformities

STUDY DESIGN

Retrospective study.

OBJECTIVE

To analyze the perioperative major non-neurological complications (MNNCs) in posterior vertebral column resection (PVCR) procedures for severe rigid deformities and to identify the factors that may increase the risk.

SUMMARY OF BACKGROUND DATA

Although surgeons constantly attempted to increase the corrective efficacy and neurological safety after PVCR, there are still significant risks of major and potentially life-threatening complications.

METHODS

A total of 105 consecutive patients with severe rigid deformity who underwent 1-stage PVCR at a single center from 2004 to 2013 were reviewed. The demographic data, medical and surgical histories, perioperative and final follow-up radiographical measurements, and prevalence of perioperative MNNCs were reviewed.

RESULTS

The mean age of patients at the time of surgery was 18.9 years (range: 10-45 yr). The major curve of scoliosis was 108.9 ± 25.5 preoperatively and 37.2 ± 16.8 at the final follow-up, and segmental kyphosis was from 89.8 ± 31.1 to 30.4 ± 15.3. There were 31 MNNCs in 24 patients: 16 respiratory complications in 13 patients, 9 cardiovascular adverse events in 7 cases, 1 malignant hyperthermia, and 1 optic deficit. There were 3 patients with wound infection, and 1 of them had to undergo partial removal of the implant for infection control. One patient with neurofibromatosis died 1 day after operation. Factors that showed no relationships with an increased prevalence of MNNCs were age, sex, presence of cardiac disease or neural axis malformation, and both sagittal and coronal correction rate. Patients with T6 and upper resected level, undergoing PVCR at the early period, showed a trend toward more MNNCs encountered. Moreover, nonidiopathic deformity, large scoliotic curve greater than 150°, percent predicated forced vital capacity and forced expiratory volume in 1 second (FEV1.0) less than 40%, and estimated blood loss volume more than 5000 mL were identified as risk factors associated with MNNCs.

CONCLUSION

Patients who had undergone PVCR experienced expected higher rate of MNNCs, with an overall prevalence of 22.9%. When considering PVCR, it is important to recognize the significantly higher inherent risks and provide appropriate preoperative counseling on the risks and benefits of surgery.

LEVEL OF EVIDENCE

3.

Intraoperative blood loss, postoperative drainage, and recovery in patients undergoing lumbar spinal surgery

Background

Spine surgery is widely accepted as an effective management for patients with lumbar disc herniation; however, the factors influencing intraoperative procedure and prognosis are not fully understood. The present study was aimed to identify the factors influencing intraoperative blood loss, postoperative drainage volume, and recovery in patients undergoing spinal surgery.

Methods

We retrospectively analyzed the clinical data of 183 consecutive patients with lumbar disc herniation who underwent spine surgery. The clinical characteristics, operation procedure, and outcome were documented and the correlations were analyzed.

Results

There were significant differences between one-level and two-level operations in the bleeding volumes of male (P = 0.005) and female (P = 0.002) patients, and in final drainage of male (P = 0.043) and female (P = 0.003) patients. The blood loss was correlated with the operation duration. There were differences in intraoperative bleeding and final drainage between groups with one-level and two-level operations. Additionally, there were differences in intraoperative autologous blood transfusion among various groups. There were significant differences in intraoperative bleeding between autologous blood transfusion and non-transfusion groups.

Conclusions

The key factors affecting the intraoperative blood loss and postoperative drainage volume include operation methods, operation duration, blood-transfusion modes, and usage of anticoagulants. These results should be taken into consideration in the attempt to optimize operation procedure and improve post-operative recovery.

Complications in operative Scheuermann kyphosis: do the pitfalls differ from operative adolescent idiopathic scoliosis?

STUDY DESIGN

A prospective multicenter database of operative patients with Scheuermann kyphosis (SK) with minimum 1-year follow-up was studied for major complications compared with contemporaneous operative patients with adolescent idiopathic scoliosis (AIS) from the database.

OBJECTIVE

To evaluate complications associated with current surgical techniques in SK and AIS.

SUMMARY OF BACKGROUND DATA

There is a paucity of literature regarding complications associated with SK surgical treatment, but prior data suggest an elevated neurological risk.

METHODS

Complication rates were compared using analysis of variance and Fisher exact test analyses. Major complications were those that were life-threatening, caused spinal cord, nerve root, or ocular injury or required reoperation including surgical site infections. A binary logistic regression determined the likelihood of complications based on diagnosis, levels fused, blood loss, operative time, and length of stay.

RESULTS

Ninety-seven patients with SK (57 males; mean age, 16.5 yr; 75.3° mean kyphosis) and 800 patients with AIS (622 females; mean age, 14.9 yr; 55.6° mean curvature) met inclusion criteria. Patients with SK had significantly more major complications than those with AIS (16.3% vs. 2.3%; P < 0.001). The SK group had more infections (10.3% vs. 0.75%) and reoperations (14.4% vs. 1.4%) (P < 0.001). Operative time was longer and more levels were fused in the SK group (P < 0.001). Surgical site infection was the most common complication. There were no significant differences in length of stay or blood loss. Patients with SK were 3.9× more likely to have a major complication than those with AIS (odds ratio: 0.26, P = 0.003). The number of levels fused was an independent predictor of major complications: each additional level fused increased the odds of a complication by 36% in both groups (odds ratio: 1.36, P = 0.034).

CONCLUSION

Major complications are 3.9× more likely to occur in operative SK than in AIS. The number of levels fused is an independent risk factor for major complications. Patients with SK are at higher risk for infections and reoperation than those with AIS.

LEVEL OF EVIDENCE

2.

Preoperative short-term traction prior to posterior vertebral column resection: procedure and role

PURPOSE

Severe rigid spine deformity with sharp curve can be effectively corrected by posterior vertebral column resection (PVCR). Meanwhile, high risk of this procedure also has been recognized generally. The aim of this study is to review and evaluate the role of preoperative skull-femoral traction prior to PVCR for extremely severe rigid spinal deformity with sharp angular curve >150°.

METHODS

Twelve cases with extremely severe rigid deformities and sharp curves were treated by skull-femoral traction before operation. For them, the mean preoperative major scoliotic curve and kyphosis were 153° (110°-168°) and 109° (61°-180°). Continuous skull-femoral traction in supine position was started 4 weeks before operation. In the process of traction, tolerance, neurologic status, deformity changes, etc., were reviewed and documented for analysis. PVCR were performed in all these patients for final and main correction.

RESULTS

The final traction force in the 12 cases was 63% of body weight. After 4-week traction, the main scoliotic curve and kyphosis were decreased by 34 and 31%. In 1 week, main scoliotic curve and kyphosis were decreased by 19 and 15%. In 2 weeks, the major scoliosis curve was decreased by 11%, but kyphosis was unexpectedly increased by 4%. Deformity in the last 2 weeks was less significant than the first 2 weeks. After PVCR, the main scoliotic curve and kyphosis were improved 69 and 66%. No permanent neurological damage occurred.

CONCLUSION

Preoperative skull-femoral traction effectively mitigates the neurological risks of PVCR for extremely severe rigid spinal deformity with sharp curve. During traction, scoliosis can be improved more significantly and easily than kyphosis.

Neuromuscular scoliosis

The purpose of this focused review is to provide an overview of neuromuscular scoliosis from the perspective of the rehabilitation physician. Scoliosis is a common consequence of neuromuscular diseases, including central nervous system disorders such as cerebral palsy and spinal cord injury; motor neuron disorders, for example, spinal muscular atrophy; muscle fiber disorders, for example, Duchenne muscular dystrophy; multifactorial disorders, for example, spina bifida; and many other neuropathic and myopathic conditions. Unlike adolescent idiopathic scoliosis, which is the most common form of spinal deformity, neuromuscular scoliosis is more severe and more progressive, and is associated with more morbidity. Factors that contribute to this spinal deformity include asymmetric paraplegia, imbalance of mechanical forces, intraspinal and congenital anomalies of the spine, altered sensory feedback, and abnormal posture via central pathways. Spinal deformity combined with limitations due to an underlying neuromuscular condition lead to significant physiologic impairments that affect limb movement, cardiopulmonary function, gait, standing, sitting, balance, trunk stability, bimanual activities, activities of daily living, and pain, as well as concerns with self-image and social interactions. Evaluation and management of this population requires understanding of disease progression, pulmonary status, functional limitations, indications for conservative and surgical interventions, and social considerations.

Failure of Monoaxial Pedicle Screws at the Distal End of Scoliosis Constructs: A Case Series

BACKGROUND

The goals of instrumented fusion for scoliosis are to correct deformities, stabilize the spine, and achieve arthrodesis. Monoaxial pedicle screws are often used in scoliosis constructs and have shown superiority over other types of pedicle screws in their ability to correct vertebral rotation and lumbar lordosis. However, because of the fixed-angle nature of the monoaxial pedicle screw head, any malalignment at the rod-screw interface could result in less than optimum stability.

RESULTS

This series exhibits 3 cases of set screw loosening with the use of monoaxial pedicle screws at the distal end of long spinal fusion constructs for the management of patients with scoliosis; these complications all occurred within 6 months of the index procedures. The results of a detailed microscopic analysis of the failed components from 1 of the cases are also presented.

CONCLUSIONS

From this evidence, the authors of the current study recommend that surgeons exercise caution when using monoaxial pedicle screws at the distal end of long spinal fusion constructs, especially after compression has been achieved on the convex portion of the curve.

Posterior instrumentation and fusion

The purpose of surgery for adolescent idiopathic scoliosis, which characteristically includes thoracic hypokyphosis and all three columns of the spine, is the achievement of a balanced spine while preserving as many motion segments as possible and avoiding neurologic damage. Many approaches have been defined in the treatment of this common disease. Posterior-only surgery, instrumentation and fusion have become the preferred technique in many centers throughout the world due to simplicity of approach, decreased risk of certain complications and the correction power of pedicle screws. This review attempts to summarize the advantages and disadvantages related to posterior instrumentation and fusion in adolescent idiopathic scoliosis.

The incidence and outcomes of vertebral column resection in paediatric patients: a population-based, multicentre, follow-up study

We report the results of vertebral column resection (VCR) for paediatric patients with spinal deformity. A total of 49 VCRs in paediatric patients from four university hospitals between 2005 and 2009 with a minimum two-year follow-up were retrospectively identified. After excluding single hemivertebral resections (n = 25) and VCRs performed for patients with myelomeningocele (n = 6), as well as spondylectomies performed for tumour (n = 4), there were 14 patients who had undergone full VCR at a mean age of 12.3 years (6.5 to 17.9). The aetiology was congenital scoliosis in five, neuromuscular scoliosis in three, congenital kyphosis in two, global kyphosis in two, adolescent idiopathic scoliosis in one and secondary scoliosis in one. A total of seven anteroposterior and seven posterolateral approaches were used. The mean major curve deformity was 86° (67° to 120°) pre-operatively and 37° (17° to 80°) at the two-year follow-up; correction was a mean of 54% (18% to 86%) in the anteroposterior and 60% (41% to 70%) in the posterolateral group at the two-year follow-up (p = 0.53). The mean Scoliosis Research Society-24 total scores were 100 (92 to 108) for the anteroposterior and 102 (95 to 105) for the posterolateral group. There was one paraparesis in the anteroposterior group necessitating urgent re-decompression, with a full recovery. Patients undergoing VCR are highly satisfied after a successful procedure.

What is the best way to optimize thoracic kyphosis correction? A micro-CT and biomechanical analysis of pedicle morphology and screw failure

STUDY DESIGN

A human cadaveric biomechanical analysis.

OBJECTIVE

The purpose of this study was to evaluate the bone density/trabecular width of the thoracic pedicle and correlate that with its resistance against compressive loading used during correction maneuvers in the thoracic spine (i.e., cantilever bending).

SUMMARY OF BACKGROUND DATA

As surgeons perform cantilever correction maneuvers in the spine, it is common to have pedicle screws pullout or displace while placing corrective forces on the construct. Currently, surgeons either compress against the cephalad aspect of the pedicle or vice versa. We set out to establish which aspect of the pedicle was the most dense and to determine the optimal direction for screw compression during kyphosis/deformity correction.

METHODS

Fifteen fresh-frozen cadaveric vertebrae (n = 15) were examined by micro-computed tomography to determine percent bone volume/total volume (%BV/TV) within the cephalad and caudad aspects of the pedicle. Specimens were sectioned in the sagittal plane. Pedicles were instrumented according to the straightforward trajectory on both sides. Specimens were then mounted and loading to failure was performed perpendicular to the screw axis (either the cephalad or the caudad aspect of the pedicle).

RESULTS

Mean failure when loading against the caudad aspect of the pedicle was statistically, significantly greater (454.5 ± 241.3 N vs. 334.79 1 ± 158.435 N) than for the cephalad pedicle (P < 0.001). In concordance with failure data, more trabecular and cortical bones were observed within the caudad half of the pedicle compared with the cephalad half (P < 0.001).

CONCLUSION

Our results suggest that the caudad half of the pedicle is denser and withstands higher forces compared with the cephalad aspect. In turn, the incidence of intraoperative screw loosening and/or pedicle fracture may be reduced if the compressive forces (cantilever bending during deformity correction) placed upon the construct are applied against the caudad portion of the pedicle.

Biomechanical analysis of 4 types of pedicle screws for scoliotic spine instrumentation

STUDY DESIGN

Numerical modeling and simulations of scoliotic spine instrumentation using monoaxial, uniaxial, polyaxial, and multiple-degrees-of-freedom (6DOF) postloading pedicle screws.

OBJECTIVE

To biomechanically analyze the general curve reduction effects and bone-screw force levels of monoaxial, uniaxial, polyaxial, and 6DOF pedicle screws for scoliotic spine instrumentation.

SUMMARY OF BACKGROUND DATA

The ideal spinal fusion construct for treating scoliosis is still debatable. Studies on the effects of different types of implants were mainly based on postoperative radiograph measurements. Systematic studies are yet to be done on how bone-screw forces are correlated with screw types.

METHODS

Computer biomechanical models were built using 3-dimensional geometry and spine stiffness of 10 patients with adolescent idiopathic scoliosis having undergone spinal instrumentation. The surgical instrumentations were simulated each time, using a different type of screw. For each case and screw type, 15 screw placement variations were simulated to investigate their effects on bone-screw forces.

RESULTS

The maximum differences between different screw types were 6.4°, 1.1°, and 4.7°, respectively, for main thoracic Cobb angles, main thoracic apical vertebral rotation, and thoracic kyphosis (1.2°, 0.3°, and 0.3° on average). The average bone-screw forces were higher for monoaxial (229 N ± 140 N) than uniaxial (206 N ± 122 N), polyaxial (141 N ± 99 N), and 6DOF screws (103 N ± 42 N). Bone-screw forces with monoaxial screws were, respectively, 1.1, 2.5, and 25 times more sensitive to screw placement variation than uniaxial, polyaxial, and 6DOF screws.

CONCLUSION

The bone-screw loads of different screws were significantly different. The descending order of bone-screw loads was monoaxial, uniaxial, polyaxial, and 6DOF screws. For patients with large and stiff spinal deformities or for patients with compromised bone quality, screws with more degrees of freedom offer better perspective to reduce bone-screw connection failure.

Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels

OBJECTIVES

To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels.

METHODS

Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level.

RESULTS

Inter-reader agreements of quantitative and qualitative parameters were high (ICC = 0.81-1.00, κ = 0.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P < 0.001), spine levels (P < 0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P < 0.01). Image quality was significantly (P < 0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V = 0.58, P < 0.001). Artefacts decreased significantly (V = 0.51, P < 0.001) at higher monoenergies. OPTkeV values ranged from 123-141 keV. OPTkeV according to vendor and spine level are presented herein.

CONCLUSIONS

Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended.

KEY POINTS

• Artefacts pose problems for CT following posterior spinal fusion implants. • CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT. • DECT extrapolation improves image quality and reduces metallic artefacts over SECT. • There were considerable differences in monoenergy values among vendors and spine levels. • Use of individualised monoenergy values is indicated for different metallic hardware devices.

The impact of halo-gravity traction on curve rigidity and pulmonary function in the treatment of severe and rigid scoliosis and kyphoscoliosis: a clinical study and narrative review of the literature

INTRODUCTION

The treatment of rigid and severe scoliosis and kyphoscoliosis is a surgical challenge. Presurgical halo-gravity traction (HGT) achieves an increase in curve flexibility, a reduction in neurologic risks through gradual traction on a chronically tethered cord and an improvement in preoperative pulmonary function. However, little is known with respect to the ideal indications for HGT, its appropriate duration, or its efficacy in the treatment of rigid deformities.

MATERIALS AND METHODS

To investigate the use of HGT in severe deformities, we performed a retrospective review of 45 patients who had severe and rigid scoliosis or kyphoscoliosis. The analysis focused on the impact of HGT on curve flexibility, pulmonary function tests (PFTs), complications and surgical outcomes in a single spine centre.

RESULTS

PFTs were used to assess the predicted forced vital capacity (FVC%). The mean age of the sample was 24±14 years. 39 patients had rigid kyphoscoliosis, and 6 had scoliosis. The mean apical rotation was 3.6°±1.4°, according to the Nash and Moe grading system. The curve apices were mainly in the thoracic spine. HGT was used preoperatively in all the patients. The mean preoperative scoliosis was 106.1°±34.5°, and the mean kyphosis was 90.7°±29.7°. The instrumentation used included hybrids and pedicle screw-based constructs. In 18 patients (40%), a posterior concave thoracoplasty was performed. Preoperative PFT data were obtained for all the patients, and 24 patients had ≥3 assessments during the HGT. The difference between the first and the final PFTs during the HGT averaged 7.0±8.2% (p<.001). Concerning the evolution of pulmonary function, 30 patients had complete data sets, with the final PFT performed, on average, 24 months after the index surgery. The mean preoperative FVC% in these patients was 47.2±18%, and the FVC% at follow-up was 44.5±17% (a difference that did not reach statistical significance). The preoperative FVC% was highly predictive of the follow-up FVC% and the response during HGT. The mean flexibility of the scoliosis curve during HGT was only 14.8±11.4%, which was not significantly different from the flexibility measures achieved on bending radiographs or Cotrel traction radiographs. In rigid curves, the Cobb angle difference between the first and final radiographs during HGT was only 8°±9° for scoliosis and 7°±12° for kyphosis. Concerning surgical outcomes, 13 patients (28.9%) experienced minor and 15 (33.3%) experienced major complications. No permanent neurologic deficits or deaths occurred. Additional surgery was indicated in 12 patients (26.7%), including 7 rib-hump resections. At the final evaluation, 69% of the patients had improved coronal balance, and at a mean follow-up of 33±23.3 months, 39 patients (86.7%) were either satisfied or very satisfied with the overall outcome.

CONCLUSION

The improvement of pulmonary function and the restoration of sagittal and coronal balance are the main goals in the treatment of severe and rigid scoliosis and kyphoscoliosis. A review of the literature showed that HGT is a useful tool for selected patients. Preoperative HGT is indicated in severe curves with moderate to severe pulmonary compromise. HGT should not be expected to significantly improve severe curves without a prior anterior and/or posterior release. The data presented in this study can be used in future studies to compare the surgical and pulmonary outcomes of severe and rigid deformities.

Two-stage posterior-only procedures for correction of severe spinal deformities

PURPOSE

To review the outcomes of surgical treatment for severe spinal deformities via a two-stage posterior-only approach.

METHODS

A total of 18 patients with large and rigid spinal deformities were studied based on clinical and radiographic data. All of them received a two-stage posterior-only approach: first on the concave side by internal distraction of pedicle screws and rods through intramuscular tunnels, followed by respiratory function exercise and improving nutritional status during the intervening period, and finally by posterior additional correction, ultimate instrumentation and spinal fusion in the second operation.

RESULTS

The mean major coronal curve was corrected by 46% after the first operation and by 60.4% after the second operation. The mean thoracic kyphosis was corrected by 50.9% after the first operation and by 64.8% after the second operation. The loss of correction mean was 3.3° for the major coronal curve and 2.6° for the thoracic kyphosis at a mean of 31.5 months follow-up. The mean operation time for the first and second operation was 186.2 and 300.6 min, and the mean intraoperative blood loss was 211.1 and 1,597.2 mL, respectively. No severe complication was noticed in this series.

CONCLUSIONS

The two-stage posterior-only procedures permitting stepwise correction for the treatment of severe spinal deformities provide safe and satisfactory outcomes in this patient population.

Evaluation of vertical traction radiography for predicting the outcome of moderate to severe rigid scoliosis correction

OBJECTIVE

To determine the efficacy of imaging patients in a state of traction ("traction imaging") for selection of upper and lower vertebrae to undergo instrumentation (UIV and LIV, respectively) to correct moderate to severe, rigid scoliosis.

METHODS

Twenty-seven patients aged 11-21 years (average, 15.5 years) who had been treated at our institution for scoliosis of the thoracic spine between 2004 and 2008 were retrospectively analyzed. All patients were treated with the third multiple hook-screw and rod instrumentation system. Standardized radiographic measurements (anteroposterior, sagittal, bending, fulcrum, traction) were taken and Cobb's angles, apical vertebra translation (AVT), and traction-stable vertebrae determined.

RESULTS

All patients were followed for 6-36 months (average, 14.7 months). The Cobb's angles under preoperative vertical traction correlated positively with those measured postoperatively in standing anteroposterior film (P < 0.01). Preoperative AVT under vertical traction was significantly different from that measured postoperatively in standing anteroposterior film (P < 0.01). The traction radiography-determined UIV slant angles were significantly different from those preoperatively without traction and the postoperative values, whereas traction radiography-determined LIV values were not significantly different from those found preoperatively without traction (P > 0.05).

CONCLUSIONS

Traction radiographic imaging is an effective, feasible preoperative assessment for determining which vertebrae are stable, designing the surgical strategy and choosing the UIV and LIV for correcting moderate to severe, rigid scoliosis.

2011 SOSORT guidelines: Orthopaedic and Rehabilitation treatment of idiopathic scoliosis during growth

BACKGROUND

The International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT), that produced its first Guidelines in 2005, felt the need to revise them and increase their scientific quality. The aim is to offer to all professionals and their patients an evidence-based updated review of the actual evidence on conservative treatment of idiopathic scoliosis (CTIS).

METHODS

All types of professionals (specialty physicians, and allied health professionals) engaged in CTIS have been involved together with a methodologist and a patient representative. A review of all the relevant literature and of the existing Guidelines have been performed. Documents, recommendations, and practical approach flow charts have been developed according to a Delphi procedure. A methodological and practical review has been made, and a final Consensus Session was held during the 2011 Barcelona SOSORT Meeting.

RESULTS

The contents of the document are: methodology; generalities on idiopathic scoliosis; approach to CTIS in different patients, with practical flow-charts; literature review and recommendations on assessment, bracing, physiotherapy, Physiotherapeutic Specific Exercises (PSE) and other CTIS. Sixty-five recommendations have been given, divided in the following topics: Bracing (20 recommendations), PSE to prevent scoliosis progression during growth (8), PSE during brace treatment and surgical therapy (5), Other conservative treatments (3), Respiratory function and exercises (3), Sports activities (6), Assessment (20). No recommendations reached a Strength of Evidence level I; 2 were level II; 7 level III; and 20 level IV; through the Consensus procedure 26 reached level V and 10 level VI. The Strength of Recommendations was Grade A for 13, B for 49 and C for 3; none had grade D.

CONCLUSION

These Guidelines have been a big effort of SOSORT to paint the actual situation of CTIS, starting from the evidence, and filling all the gray areas using a scientific method. According to results, it is possible to understand the lack of research in general on CTIS. SOSORT invites researchers to join, and clinicians to develop good research strategies to allow in the future to support or refute these recommendations according to new and stronger evidence.