Paediatric syndromic scoliosis: proceedings of the half-day course at the 57th annual meeting of the Scoliosis Research Society.

There are some syndromes that present with unique manifestations pertaining to the spinal column. A good working understanding of these common syndromes is useful for the spinal deformity surgeons and related healthcare providers. This review attempts to encompass these unique features and discuss them in three broad groups: hypermobility syndromes, muscle pathology-related syndromes, and syndromes related to poor bone quality. This review explores the features of these syndromes underpinning the aspects of surgical and medical management. This review represents the proceedings of the Paediatric Half-Day Course at the 57th Annual Meeting of the Scoliosis Research Society.

Growing rods in Early Onset Scoliosis: The current scenario.

Background and aims: The treatment of early onset scoliosis is a challenge. Some curves resolve spontaneously, while the more aggressive ones require surgical intervention. Several surgical strategies have been explored in this unique group of patients, though the distraction based growing rods are the mainstay of treatment. The aim of this paper is to consider the current scenario with the surgical treatment for early onset scoliosis with growing rods. Methods: This is a narrative review that explores the various types of growing rod options that are currently available. The results, as reported in literature, are discussed. The complications and problems with the commonly used growing rods are explored, based on the reported literature and on retrieval analysis that we have published. We discuss some of the newer modifications of growing rods. Results: There is no real consensus on the ideal timing for the surgery or ways to assess the outcomes of the treatment. The Cobb angle measurement and measures of thoracic growth are surrogate markers. The main indication for surgery is to an increase in the thoracic dimensions and allowing for lung growth. Measures that are linked to lung function are more useful. We report some newer MRI scanning technology. Distraction-based growing rods have been reported to produce consistent and good results. Frequent return to theatre with the Traditional Growing Rods (TGR) and the metallosis related problems with the MCGR are reported. Conclusions: We have learned a lot from the TGR and MCGR experiences. There is a scope for ongoing research to improve the design of the implant systems and better assess the outcomes on lung function. This review outlines these and helps identify the future trends.

A Comparison of Magnetic Resonance Imaging and SPECT-CT Imaging in Complex Spine Pathology: Does SPECT-CT Provide Additional Diagnostic Information Over Magnetic Resonance Imaging?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Magnetic Resonance Imaging (MRI) is often regarded as the gold standard for spinal pathology, as it provides good structural visualisation. SPECT-CT, however, provides combined structural and functional information. There is a paucity of literature comparing SPECT-CT with MRI in the spine. Our aim was to determine whether SPECT-CT provides additional information to MRI in individuals with complex spinal pathology, including deformity, which altered management. METHODS: We conducted a retrospective review of all individuals seen at our tertiary spinal unit that were investigated with both MRI and SPECT-CT of the spine between 2007-2020. We reviewed imaging reports, and collated diagnoses, surgical treatment and the relative contributions of MRI and SPECT-CT to management decisions. RESULTS: 104 individuals identified, with a mean age of 30 years (89 females and 15 males). Diagnostic categories were adolescent, adult, and congenital deformity, degenerative pathology, and miscellaneous pathology. MRI returned positive findings in 58 (55.8%), and SPECT-CT in 41 (39.4%) cases. SPECT-CT identified 10 cases of facet joint degeneration, 5 of increased uptake around metalwork suggestive of loosening, 1 pseudoarthrosis, 1 partial failure of fusion and 1 osteoid osteoma which were not reported on MRI, all in individuals who had previously undergone spinal instrumentation. Despite this, SPECT-CT only altered management for 6 individuals (5.8%). CONCLUSIONS: MRI is less useful in the setting of previous instrumentation due to metal artefact. Where MRI is inconclusive, particularly in individuals with previous spinal instrumentation, SPECT-CT may provide a diagnosis, but is not recommended as primary imaging.

A comparison of the post-fusion outcome of patients with early-onset scoliosis treated with traditional and magnetically controlled growing rods.

AIMS: The aim of this study was to compare the clinical and radiological outcomes of patients with early-onset scoliosis (EOS), who had undergone spinal fusion after distraction-based spinal growth modulation using either traditional growing rods (TGRs) or magnetically controlled growing rods (MCGRs). METHODS: We undertook a retrospective review of skeletally mature patients who had undergone fusion for an EOS, which had been previously treated using either TGRs or MCGRs. Measured outcomes included sequential coronal T1 to S1 height and major curve (Cobb) angle on plain radiographs and any complications requiring unplanned surgery before final fusion. RESULTS: We reviewed 43 patients (63% female) with a mean age of 6.4 years (SD 2.6) at the index procedure, and 12.2 years (SD 2.2) at final fusion. Their mean follow-up was 8.1 years (SD 3.4). A total of 16 patients were treated with MCGRs and 27 with TGRs. The mean number of distractions was 7.5 in the MCGR group and ten in the TGR group (p = 0.471). The mean interval between distractions was 3.4 months in the MCGR group and 8.6 months in the TGR group (p < 0.001). The mean Cobb angle had improved by 25.1° in the MCGR group and 23.2° in TGR group (p = 0.664) at final follow-up. The mean coronal T1 to S1 height had increased by 16% in the MCGR group and 32.9% in TGR group (p = 0.001), although the mean T1 to S1 height achieved at final follow-up was similar in both. Unplanned operations were needed in 43.8% of the MCGR group and 51.2% of TGR group (p = 0.422). CONCLUSION: In this retrospective, single-centre review, there were no significant differences in major curve correction or gain in spinal height at fusion. Although the number of planned procedures were fewer in patients with MCGRs, the rates of implant-related complications needing unplanned revision surgery were similar in the two groups. Cite this article: Bone Joint J 2022;104-B(2):257-264.

Radiation exposure during the treatment of spinal deformities.

AIMS: To benchmark the radiation dose to patients during the course of treatment for a spinal deformity. METHODS: Our radiation dose database identified 25,745 exposures of 6,017 children (under 18 years of age) and adults treated for a spinal deformity between 1 January 2008 and 31 December 2016. Patients were divided into surgical (974 patients) and non-surgical (5,043 patients) cohorts. We documented the number and doses of ionizing radiation imaging events (radiographs, CT scans, or intraoperative fluoroscopy) for each patient. All the doses for plain radiographs, CT scans, and intraoperative fluoroscopy were combined into a single effective dose by a medical physicist (milliSivert (mSv)). RESULTS: There were more ionizing radiation-based imaging events and higher radiation dose exposures in the surgical group than in the non-surgical group (p < 0.001). The difference in effective dose for children between the surgical and non-surgical groups was statistically significant, the surgical group being significantly higher (p < 0.001). This led to a higher estimated risk of cancer induction for the surgical group (1:222 surgical vs 1:1,418 non-surgical). However, the dose difference for adults was not statistically different between the surgical and non-surgical groups. In all cases the effective dose received by all cohorts was significantly higher than that from exposure to natural background radiation. CONCLUSION: The treatment of spinal deformity is radiation-heavy. The dose exposure is several times higher when surgical treatment is undertaken. Clinicians should be aware of this and review their practices in order to reduce the radiation dose where possible. Cite this article: Bone Joint J 2021;103-B(4):1-7.

Prediction of Scoliosis Curve Correction Using Pedicle Screw Constructs in AIS: A Comparison of Fulcrum Bend Radiographs and Traction Radiographs Under General Anesthesia.

STUDY DESIGN: Retrospective radiographic review. OBJECTIVES: Our objectives were to (1) compare the ability of fulcrum bend radiographs and traction radiographs under general anesthesia to predict correction of adolescent idiopathic scoliosis (AIS) using pedicle screw only constructs and (2) compare the fulcrum bend correction index (FBCI) with a new measurement: the traction correction index (TCI). METHODS: This is a retrospective radiographic review of 80 AIS patients (62 female and 18 male), who underwent scoliosis correction with pedicle screw only constructs. The mean age at surgery was 14 years (range 9-20 years). Radiographic analysis was carried out on the preoperative and immediate postoperative posteroanterior standing radiographs and the preoperative fulcrum bend radiographs and traction radiographs under general anesthesia. FBCI is calculated by dividing the correction rate by the fulcrum flexibility and TCI is calculated by dividing the correction rate by the traction flexibility. RESULTS: Preoperative mean Cobb angle of 63.9° was corrected to 25.8° postoperatively. The mean fulcrum bending Cobb angle was 37.6° and traction Cobb angle was 26.6°. The mean fulcrum flexibility was 41.1%, traction flexibility 58.4%, and correction rate 59.6%. The median FBCI was 137% and TCI was 104.3%. CONCLUSIONS: When comparing fulcrum bend and traction radiographs, we found the traction radiographs to be more predictive of curve correction in AIS using pedicle screw constructs. TCI takes into account the curve flexibility better than FBCI.

Magnetically Controlled Growing Rods: The Experience of Mechanical Failure from a Single Center Consecutive Series of 28 Children with a Minimum Follow-up of 2 Years.

STUDY DESIGN: Retrospective observational study of a continuous series of 28 children. PURPOSE: To determine the mechanical failure rate in our cohort of children treated with magnetically controlled growth rods (MCGRs). OVERVIEW OF LITERATURE: Previous studies report a MCGR mechanical failure rate of 0%-75%. METHODS: All patients with MCGR implantation between 2012 and 2015 were examined and followed up for a minimum of 2 years. A retrospective evaluation of contemporaneously documented clinical findings was conducted, and radiographs were retrospectively examined for mechanical failure. The external remote controller (ERC)-specified length achieved in the clinic was compared to the length measured on subsequent radiographs. RESULTS: Fourteen mechanical failures were identified in 28 children (50%) across a total of 52 rods (24 pairs and four single constructs). Mechanical failures were due to: failure to lengthen under general anesthesia (seven children), actuator pin fracture (four), rod fracture (one), foundation screw failure (one), and ran out of rod length (one). Of the 14 mechanical failures, six were treated with final fusion operations (reflecting limited further growth potential), and eight patients were treated with the intention for further lengthening. We therefore consider these eight patients to represent the true incidence of mechanical failure in our cohort (29%). The difference between the ERC length and radiographic length was found to be identical in 11% cases; 35% were overestimates, and 54% were underestimates. The median underestimate was 2.45 mm whereas the median overestimate was 3.1 mm per distraction episode. In total, 95% of all ERC distractions were within ±10 mm of the radiographic length achieved over a median of nine distraction episodes. CONCLUSIONS: Our series is the most comprehensive MCGR series published to date, and we present a mechanical failure rate of 29%. Clinicians should be mindful of the discrepancies between ERC length and radiographic measurements of rod length; other modalities may be more helpful in this regard.

In vitro biomechanical study of pedicle screw pull-out strength based on different screw path preparation techniques.

BACKGROUND: Poor screw-to-bone fixation is a clinical problem that can lead to screw loosening. Under-tapping (UT) the pedicle screw has been evaluated biomechanically in the past. The objective of the study was to determine if pedicle preparation with a sequential tapping technique will alter the screw-to-bone fixation strength using a stress relaxation testing loading protocol. MATERIALS AND METHODS: Three thoracolumbar calf spines were instrumented with pedicle screws that were either probed, UT, standard-tapped (ST), or sequential tapped to prepare the pedicle screw track and a stress relaxation protocol was used to determine pull-out strength. The maximum torque required for pedicle screw insertion and pull-out strength was reported. A one-way ANOVA and Tukeys post-hoc test were used to determine statistical significance. RESULTS: The pedicle screw insertion torques for the probed, UT, ST and sequentially tapped (SQT) techniques were 5.09 (±1.08) Nm, 5.39 (±1.61) Nm, 2.93 (±0.43) Nm, and 3.54 (±0.67) Nm, respectively. There is a significant difference between probed compared to ST (P ≤ 0.05), as well as UT compared to both ST and SQT (P ≤ 0.05). The pull-out strength for pedicle screws for the probed, UT, ST and SQT techniques was 2443 (±782) N, 2353(±918) N, 2474 (±521) N, and 2146 (±582) N, respectively, with no significant difference (P ≥ 0.05) between techniques. CONCLUSIONS: The ST technique resulted in the highest pull-out strength while the SQT technique resulted in the lowest. However, there was no significant difference in the pull-out strength for the various preparation techniques and there was no correlation between insertion torque and pull-out strength. This suggests that other factors such as bone density may have a greater influence on pull-out strength.

A slip above a slip: retrolisthesis of the motion segment above a spondylolytic spondylolisthesis.

OBJECTIVE: The purpose of this study is to assess the degenerative changes in the motion segments above a L5S1 spondylolytic spondylolisthesis and to view these in light of the retrolisthesis in the segment immediately above the slip. A spondylolytic spondylolisthesis causes an abnormal motion and predisposes to degenerative changes at the L5S1 disc. Degenerative changes in the adjacent segments would influence the symptomatology and natural history of the disease and the treatment options. The extent of degenerative changes in the levels immediately above a L5S1 spondylolytic spondylolisthesis is not well documented in the literature. We have noted retrolisthesis at this level, but this has not been previously reported or assessed. MATERIALS AND METHODS: Thirty-eight patients with a symptomatic L5S1 spondylolytic spondylolisthesis with a mean age of 52.8 years (95% CI 47.2-58.4); 55.3% (n = 21) females and 44.7% (n = 17) males. We assessed the lumbar lordosis, slip angle, sacral slope, grade of the slip, facet angles at L34 and L45 on both sides, facet degenerative score (cartilage and sclerosis values), disc degenerative score (Pfirrmann) at L34, L45 and L5S1 and the presence of retrolisthesis at L45. RESULTS: We noted that 29% (11) had a retrolisthesis at L45. The degenerative scores reduced significantly from L5S1 through L45 and L34. Slip angle and L45 disc degenerative score were the only factors that occurred consistently in patients with a retrolisthesis. CONCLUSIONS: There is a cascade of degenerative changes that involve both the disc and the facet joints at the levels above a spondylolytic spondylolisthesis. The degenerative changes at the L45 disc and a higher slip angle are consistent findings in patients with a retrolisthesis at the level above the slip.

Short segment bone-on-bone instrumentation for adolescent idiopathic scoliosis: a mean follow-up of six years.

STUDY DESIGN: Prospective case series. OBJECTIVE: To evaluate the clinical and radiologic outcomes of short segment anterior scoliosis surgery with bone-on-bone apposition using a dual screw, dual rod system. SUMMARY OF BACKGROUND DATA: Posterior segmental fixation for correction of AIS involves instrumentation of all the vertebrae included in the major curve. Our short segment anterior technique produces similar results by fusion of fewer levels. METHODS: Forty-five patients operated between 1996 and 2004. Twenty-eight thoracic (Lenke 1) and 17 thoracolumbar (Lenke 5). The mean age was 19 years, 87% were females, and the mean follow-up was 72 months (range 28-121 months). We operated on curves less than 85° with "total discectomy," bone-on-bone apposition, and dual-screw, dual-rod fixation. RESULTS: A mean of five vertebrae (four discs) were instrumented, with a mean operative time of 360 minutes, blood loss of 877 mL and a hospital stay of 9.1 day. Lenke 1. The main preop thoracic curve was 52.5°, final postop curve 27.9°, by fusing five vertebrae, four discs. A spontaneous improvement of 47.5% of the lumbar compensatory curve was seen. The lower tilt angle corrected from 20.9° to 11°. Lenke 5. The preoperative thoracolumbar major curve corrected from 50.5° to 18.3° (final) with fusion of four vertebrae, three discs. A spontaneous improvement of 37.4% occurred in the thoracic compensatory curve. The preop tilt angle improved from 27.7° to 8.3°.The sagittal and coronal balance was restored in all the patients. There were no neurologic, vascular, pulmonary, or implant-related complications. Union occurred within 3 months. All the patients returned to an unrestricted lifestyle within 4 months. CONCLUSION: We report good results after surgical correction using our short segment bone-on-bone technique. Improvements were noted and maintained, over a 6-year period.

Correction of neuromuscular scoliosis in patients with preexisting respiratory failure.

STUDY DESIGN: A prospective observational study in scoliosis patients who were on noninvasive night ventilation for respiratory failure. OBJECTIVE: To report the results of spinal deformity correction in a group of patients with progressive scoliosis and rare forms of muscular dystrophy/myopathy with respiratory failure who were on nocturnal ventilatory support at the time of surgery. SUMMARY OF BACKGROUND DATA: This is the first study on the results of deformity correction in a series of patients on ventilatory support. MATERIALS AND METHODS: Eight patients (6 males, 2 females) presented with progressive scoliosis and respiratory failure. The mean age at surgery was 12 years (range, 8-15 years). The mean follow-up was 48 months (range, 12-80 months). Outcome measures include lung function (spirometry), overnight pulse oximetry, Cobb angles, duration of stay in Intensive care (ICU), and the total hospital stay. RESULTS: The mean stay in the ICU was 2.7 days (range, 2-5 days). The mean hospital stay was 14.2 days (range, 10-21 days). The mean preoperative Cobb angle was 70.2 degrees (55 degrees -85 degrees ). This changed to 32 degrees (16 degrees -65 degrees ) after surgery (P = 0.0002). The mean vital capacity at the time of surgery was 20% (range, 13%-28%). The mean vital capacity of patients at last follow-up was 18% (range, 10%-31%). The desaturation noted on the preventilation overnight oximetry was reversed by nocturnal ventilation. All patients recovered well following surgery with no major cardiac or pulmonary complications. CONCLUSION: Patients with preexisting respiratory failure on nocturnal noninvasive ventilation can be safely operated for deformity correction. This can help to significantly improve their quality of life.