We report on a 13-year-old boy who presented with multiple hereditary exostosis and had development of back pain, associated with neurological deficits, and was found to have exostoses in the spinal canal. Spine radiograph showed a cauliflower-like abnormality of multiple exostoses of the posterior arch (pedicle) of the thoracic vertebrae (T3–5). Reformatted CT scanning revealed the simultaneous development of intra- and extraspinal osteochondromatosis of T3–5. The spinal cord was compressed by the intraspinal exostosis. Our patient was surgically treated for intraspinal exostoses and showed cessation of neurological deficits. We report what might be a rare association of spinal cord compression in a patient with multiple hereditary exostoses.
Spinal cord compression and associate neurological impairment is rare in patients with scoliosis and neurofibromatosis. Common reasons are vertebral subluxation, dislocation, angulation and tumorous lesions around the spinal canal. Only twelve cases of intraspinal rib dislocation have been reported in the literature. The aim of this report is to present a case of rib penetration through neural foramen at the apex of a scoliotic curve in neurofibromatosis and to introduce a new clinical sign for its detection.
A 13-year-old girl was evaluated for progressive left thoracic kyphoscoliotic curve due to a type I neurofibromatosis. Clinical examination revealed multiple large thoracic and abdominal "cafe-au-lait" spots, neurological impairment of the lower limbs and the presence of a thoracic gibbous that was painful to pressure at the level of the left eighth rib (Painful Rib Hump). CT-scan showed detachment and translocation of the cephalic end of the left eighth rib into the adjacent enlarged neural foramen. The M.R.I. examination of the spine showed neither cord abnormality nor neurogenic tumor.
The patient underwent resection of the intraspinal mobile eighth rib head and posterior spinal instrumentation and was neurologically fully recovered six months postoperatively.
Spine surgeons should be aware of intraspinal rib displacement in scoliotic curves in neurofibromatosis. Painful rib hump is a valuable diagnostic tool for this rare clinical entity.
Multiple hereditary osteochondromatosis is a genetically transmitted disorder consisting of multiple projections of bone capped by cartilage, which are called exosloses. Spinal cord compression due to expansion of a laminar osteochondroma is rare but well recognized. Surgical decompression usually improves the patient's neurological status but, in cervical exostosis, postlaminectomy kyphosis and instability problems, especially in the high-risk adolescent group, form the most significant potential difficulties in the postoperative period. We report a case of cervical laminar exostosis that was treated by anterior stabilization and fusion and discuss the benefits of this technique.
Cervical exostosis; Osteochondroma; Postlaminectomy kyphosis; Stabilization
Cervical cord compression due to osteochondroma in hereditary multiple exostosis (HME) is a rare condition, especially in young children. In this report, we discuss a rare case of cervical osteochondroma presenting as Brown-Sequard syndrome (BSS) in a 7-year-old boy with HME. The child was admitted because of hemiparesis involving the right limbs and hypoesthesia on the left side following mild trauma. MR image revealed cord compression by osteochondroma of the C7 lamina. We removed the osteocondroma and the neurological deficit was improved.
Osteochondroma; Hereditary multiple exostosis; Brown-Sequard syndrome
The objective of the study was to report a rare occurrence of dislocation and intrusion of two rib heads into the spinal canal at the convex apex of a post-traumatic thoracic scoliosis in an adult in the absence of any neurological impairment. A 47-year-old male presented with a slowly progressive, post-traumatic thoracic scoliosis and a mild aching sensation over the posterior chest wall. The lower limb neurology and bowel and bladder function were normal. There was no clinical evidence of neurofibromatosis. CT scans showed that the 8th and 9th ribs on the convex apex of the scoliotic curve had intruded into the spinal canal and were lying adjacent to the dura and spinal cord. The MRI scan did not show any cord signal intensity changes. Although rib dislocation and intrusion into the spinal canal is uncommon, images should be carefully analysed to rule out this condition in sharp angular scoliotic curves.
Post-traumatic scoliosis; Thoracic scoliosis; Rib dislocation; Rib intrusion
Scoliosis is a complex three-dimensional deformity of the spine and rib cage frequently treated by brace. Although bracing produces significant correction in the frontal plane, it generally reduces the normal sagittal plane curvatures and has limited effect in the transverse plane. The goal of this study is to develop a new optimization approach using a finite element model of the spine and rib cage in order to find optimal correction patterns. The objective function to be minimized took account of coronal and sagittal offsets from a normal spine at the thoracic and lumbar apices as well as the rib hump. Two different optimization studies were performed using the finite element model, which was personalized to the geometry of 20 different scoliotic patients. The first study took into account only the thoracic deformity, while the second considered both the thoracic and lumbar deformities. The optimization produced an average of 56% and 51% reduction of the objective function respectively in the two studies. Optimal forces were mostly located on the convex side of the curve. This study demonstrates the feasibility of using an optimization approach with a finite element model of the trunk to analyze the biomechanics of bracing, and may be useful in the design of new and more effective braces.
Key words Scoliosis; Optimization; Biomechanical; model; Brace; 3D correction
Numerous studies have attempted to quantify the correlation between the surface deformity and the Cobb angle without considering growth as an important factor that may influence this correlation. In our series, we noticed that in some younger referred children from the school-screening program there is a discrepancy between the thoracic scoliometer readings and the morphology of their spine. Namely there is a rib hump but no spinal curve and consequently no Cobb angle reading in radiographs, discrepancy which fades away in older children. Based on this observation, we hypothesized that in scoliotics the correlation between the rib cage deformity and this of the spine is weak in younger children and vice versa.
Eighty three girls referred on the basis of their hump reading on the scoliometer, with a mean age of 13.4 years old (range 7–18), were included in the study. The spinal deformity was assessed by measuring the thoracic Cobb angle from the postero-anterior spinal radiographs. The rib cage deformity was quantified by measuring the rib-index at the apex of the thoracic curve from the lateral spinal radiographs. The rib-index is defined as the ratio between the distance of the posterior margin of the vertebral body and the most extended point of the most projecting rib contour, divided by the distance between the posterior margin of the same vertebral body and the most protruding point of the least projecting rib contour. Statistical analysis included linear regression models with and without the effect of the variable age. We divided our sample in two subgroups, namely the younger (7–13 years old) and the older (14–18 years old) than the mean age participants. A univariate linear regression analysis was performed for each age group in order to assess the effect of age on Cobb angle and rib index correlation.
Twenty five per cent of patients with an ATI more than or equal 7 degrees had a spinal curve under 10 degrees or had a straight spine. Linear regressions between the dependent variable "Thoracic Cobb angle" with the independent variable "rib-index" without the effect of the variable "age" is not statistical significant. After sample split, the linear relationship is statistically significant in the age group 14–18 years old (p < 0.03).
Growth has a significant effect in the correlation between the thoracic and the spinal deformity in girls with idiopathic scoliosis. Therefore it should be taken into consideration when trying to assess the spinal deformity from surface measurements. The findings of the present study implicate the role of the thorax, as it shows that the rib cage deformity precedes the spinal deformity in the pathogenesis of idiopathic scoliosis.
The goal of this study was to observe scoliotic subjects during level walking to identify asymmetries—which may be related to a neurological dysfunction or the spinal deformity itself—and to correlate these to the severity of the scoliotic curve.
We assessed the gait pattern of ten females (median age 14.4) with idiopathic scoliosis characterised by a left-lumbar and a right-thoracic curve component. Gait analysis consisted of 3D kinematic (VICON) and kinetic (Kistler force plates) measurements. The 3D-segment positions of the head, trunk and pelvis, as well as the individual joint angles of the upper and lower extremities, were computed during walking and static standing. Calculation of pertinent kinetic and kinematic parameters allowed statistical comparison.
All subjects walked at a normal velocity (median: 1.22 m/s; range:1.08–1.30 m/s; height-adjusted velocity: 0.75 m/s; range: 0.62–0.88 m/s). The timing of the individual gait phases was normal and symmetrical for the whole group. Sagittal plane hip, knee and ankle motion followed a physiological pattern. Significant asymmetry was observed in the trunk’s rotational behaviour in the transverse plane. During gait, the pelvis and the head rotated symmetrically to the line of progression, whereas trunk rotation was asymmetric, with increased relative forward rotation of the right upper body in relation to the pelvis. This produced a torsional offset to the line of progression. Minimal torsion (at right heel strike) measured: median 1.0° (range: 5.1°–8.3°), and maximal torsion (at left heel strike) measured 11.4° (range 6.9°–17.9°). The magnitude of the torsional offset during gait correlated to the severity of the thoracic deformity and to the standing posture, whereas the range of the rotational movement was not affected by the severity of the deformity. The ground reaction forces revealed a significant asymmetry of [Msz], the free rotational moment around the vertical axis going through the point of equivalent force application. On the right side, the initial endo-rotational moment was lower, followed by a higher exo-rotational moment than on the left. All the other force parameters (vertical, medio–lateral, anterior–posterior), did not show a significant side difference for the whole group. The use of a brace stiffened torsional motion. However the torsional offset and the asymmetry of the free rotational moment remained unchanged.
The most significant and marked asymmetry was seen in the transverse plane, denoted as a torsional offset of the upper trunk in relation to the symmetrically rotating pelvis. This motion pattern was reflected by a ground-reaction-force asymmetry of the free rotational moment. Further studies are needed to investigate whether this behaviour is solely an expression of the structural deformity or whether it could enhance the progression of the torsional deformity.
Idiopathic scoliosis; Gait analysis; Biomechanics; Asymmetry
Rib displacement into the spinal canal is a rare cause of paraplegia or paraparesis in patients affected by neurofibromatous scoliosis. We describe a case of paraparesis in a 14-year-old child affected by neurofibromatous dystrophic kyphoscoliosis, treated with combined posterior and anterior spinal arthrodesis. Seventeen days after the surgical treatment the patient developed clinical signs and symptoms of paraparesis. A CT scan showed the head of the fifth rib protruding into the spinal canal with cord compression. Rib resection and posterior cord decompression were carried out following complete neurological recovery.
Kyphosis; Neurofibromatosis; Paraparesis; Rib displacement; Scoliosis
The role of rib cage in the development of progressive infantile idiopathic scoliosis (IIS) has not been studied previously. No report was found for rib growth in children with IIS. These findings caused us to undertake a segmental radiological study of the spine and rib-cage in children with progressive IIS. The aim of the present study is to present a new method for assessing the thoracic shape in scoliotics and in control subjects and to compare the findings between the two groups.
Materials and methods
In the posteroanterior (PA) spinal radiographs of 24 patients with progressive IIS, with a mean age of 4.1 years old, the Thoracic Ratios (TRs) (segmental convex and concave TRs), the Cobb angle, the segmental vertebral rotation and vertebral tilt were measured. In 233 subjects, with a mean age of 5.1 years old, who were used as a control group, the segmental left and right TRs and the total width of the chest (left plus right TRs) were measured in PA chest radiographs. Statistical analysis included Mann-Whitney, Spearman correlation coefficient, multiple linear regression analysis and ANOVA.
The comparison shows that the scoliotic thorax is significantly narrower than that of the controls at all spinal levels. The upper chest in IIS is funnel-shaped and the vertebral rotation at T4 early in management correlates significantly with the apical vertebral rotation at follow up.
The IIS thorax is narrower than that of the controls, the upper chest is funnel-shaped and there is a predictive value of vertebral rotation at the upper limit of the thoracic curve of IIS, which reflects, impaired rib control of spinal rotation possibly due to neuromuscular factors, which contribute also to the funnel-shaped chest.
Although the structural changes occurring in the scoliotic spine have been reported as early as the 19th century, the descriptions and biomechanical explanations have not always been complete and consistent. In this study, three-dimensionally rendered CT images of two human skeletons with a scoliotic deformity and two patients with serious scoliosis were used to describe the intrinsic vertebral and rib deformities. The pattern of structural deformities was found to be consistent. Apart from the wedge deformation of the apical vertebrae, a rotation deformity was found in the transversal plane between the vertebral body and the posterior complex: the vertebral body was maximally rotated towards the convexity of the scoliotic curve, whereas the tip of the spinous process was pointed to posterior. The rib deformities at the convex side of the scoliotic curve showed an increased angulation of the rib at the posterior angle, whereas the rib curve on the concave side was flattened. The observed vertebral deformities suggest that these are caused by bone remodelling processes due to forces in the anterior spinal column, which drive the apical vertebral body out of the midline, whereas forces of the musculo-ligamentous structures at the posterior side of the spinal column attempt to minimize the deviations and rotations of the vertebrae. The demonstrated rib deformities suggest an adaptation to forces imposed by the scoliotic spine.
Key words Scoliosis; Scoliosis; deformity; Scoliosis; vertebra; Scoliosis; rib; Scoliosis; biomechanics
It is generally recognized that progressive adolescent idiopathic scoliosis (AIS) evolves within a self-sustaining biomechanical process involving asymmetrical growth modulation of vertebrae due to altered spinal load distribution. A biomechanical finite element model of normal thoracic and lumbar spine integrating vertebral growth was used to simulate the progression of spinal deformities over 24 months. Five pathogenesis hypotheses of AIS were represented, using an initial geometrical eccentricity (gravity line imbalance of 3 mm or 2° rotation) at the thoracic apex to trigger the self-sustaining deformation process. For each simulation, regional (thoracic Cobb angle, kyphosis) and local scoliotic descriptors (axial rotation and wedging of the thoracic apical vertebra) were evaluated at each growth cycle. The simulated AIS pathogeneses resulted in the development of different scoliotic deformities. Imbalance of 3 mm in the frontal plane, combined or not with the sagittal plane, resulted in the closest representation of typical scoliotic deformities, with the thoracic Cobb angle progressing up to 39° (26° when a sagittal offset was added). The apical vertebral rotation increased by 7° towards the convexity of the curve, while the apical wedging increased to 8.5° (7.3° with the sagittal eccentricity) and this deformity evolved towards the vertebral frontal plane. A sole eccentricity in the sagittal plane generated a non-significant frontal plane deformity. Simulations involving an initial rotational shift (2°) in the transverse plane globally produced relatively small and non-typical scoliotic deformations. Overall, the thoracic segment predominantly was sensitive to imbalances in the frontal plane, although unidirectional geometrical eccentricities in different planes produced three-dimensional deformities at the regional and vertebral levels, and their deformities did not cumulate when combined. These results support the hypothesis of a prime lesion involving the precarious balance in the frontal plane, which could concomitantly be associated with a hypokyphotic component. They also suggest that coupling mechanisms are involved in the deformation process.
Idiopathic scoliosis; Pathogenesis; Biomechanical modeling; Growth modulation; Spine; Vertebra
We report a case of a 21-year old male with an asymptomatic solitary costal exostosis incidentally detected on a chest X-ray. The exostosis originated from the costochondral junction of the left fourth rib and protruded into the thoracic cavity. Exploratory thoracoscopy showed that the exostosis had scratched the adjacent pericardium and visceral pleura. A 5.5-cm long rib segment including the exostosis was excised. This report describes that the thoracoscopic findings of an asymptomatic costal exostosis originate from the costochondral junction, demonstrating that this condition may cause more extensive thoracic organ injury than expected.
Costal exostosis; Intrathoracic organ injury; Surgery; Thoracoscopy
Study design: Case report.
Clinical question: To report successful surgical therapy for spinal cord compression in a patient with spinal metastases from a pancreatic gastrinoma.
Methods: A 43-year-old man presented three times within 4 years with cervical and upper thoracic spinal cord compression because of metastatic gastrinoma. He had two previous spine metastases to the lower thoracic and lumbar spine, a T11 compressive lesion which required a T9L1 fusion, and an L4 lesion that was treated with chemotherapy and stereotactic radiation. The compression was relieved each time by surgery.
Results: The patient underwent three surgeries in 4 years: (1) debulking and removal of the rib head on the left at T3, and debulking of the tumor at T3 with hemilaminectomy and spinal cord decompression with internal fixation from T1–T5 using posterolateral instrumented fusion and allograft; (2) anterior C7 corpectomy with placement of a cage from C7–T1 with both anterior and posterior fusion of C2C7; and (3) T1–T3 laminectomy, T1–T3 exploration of wound, revision of hardware, T1–T3 removal of spinal tumor, and T3 bilateral transpedicular circumferential decompression. The patient is alive and regained the ability to walk 8 years after initial diagnosis, despite the appearance of spinal metastases 1 year after the diagnosis of liver metastases.
Conclusion: Surgery for spinal cord compression in patients with metastatic neuroendocrine tumors can be effective in relieving radicular pain, weakness and numbness, and while not curative can greatly improve quality of life.
Rib cage deformity is an important component of scoliosis, but few authors have reported the three-dimensional (3-D) effect of surgical procedures with posterior instrumentation systems on the shape of the rib cage. The objective of this prospective clinical study was to measure the short-term 3-D changes in the shape of the rib cage at the apex of the curve after corrective surgery of adolescent idiopathic scoliosis by a posterior approach using a multi rod, hook and screw system. The 3-D shape of the spine and rib cage was modelled pre- and postoperatively using a 3-D reconstruction technique based on multi-planar radiography in a group of 29 adolescents with idiopathic scoliosis. Geometrical indices describing the scoliotic deformity of the rib cage were computed from these models and were compared pre- and postoperatively using Student's t-tests. The frontal spinal curve correction averaged 53% in the frontal plane, while no significant change was noted in the sagittal plane. Significant changes were noted in the shape of the rib cage: rib hump at the apex and at the adjacent lower level were improved (36% and 38%), and small but significant differences were detected in rib frontal orientation in the concavity of the curves at the apex and adjacent lower rib levels. Multi rod, hook and screw instrumentation systems, such as Cotrel-Dubousset instrumentation, are effective in producing significant improvements in the 3-D shape of the rib cage, but these changes are less important than those observed at the spine level.
Idiopathic scoliosis Surgery Three-dimensional instrumentation Three-dimensional reconstruction Rib cage
The Vertical Expandable Prosthetic Titanium Rib (VEPTR™; Synthes North America, West Chester, PA) reportedly controls spinal deformity associated with constrictive chest wall conditions.
We asked whether spine-to-spine constructs using VEPTR™ instrumentation in combination with standard spinal instrumentation could be deployed to salvage failed rib-to-spine constructs used originally in patients with constricted chest walls and to primarily treat progressive spinal deformity without chest wall abnormalities.
Patients and Methods
Fifty patients were treated with VEPTR™ constructs for thoracic insufficiency syndrome at our center between 2001 and 2007. Fourteen of these 50 patients had placement of a spine-to-spine construct using a VEPTR™ implant in combination with standard spinal implants and are the subject of this retrospective review. Five had prior rib-based VEPTR™ or growing implants with an average of two failures before this surgery. Radiographic variables, preceding treatment, complications, and changes in ambulatory status, were recorded. The minimum followup was 2 years (mean, 35 months; range, 2–4 years).
After an average of five expansions in these 14 patients, positive changes were recorded for Cobb angle, T1–S1 height, sagittal balance, and space available for the lung. Complications included two rod fractures, two superficial infections, and one deep infection with rod removal.
VEPTR™ instrumentation as a spine-to-spine growing-rod construct demonstrated ease of implantation and expansion, with complication rates similar to other reported devices. This study suggests growing constructs using VEPTR™ can be used with relatively few complications and extends the potential uses of this instrumentation system.
Level of Evidence
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
Hereditary multiple exostosis (HME) is characterised by multiple osteochondromas that are distributed throughout the skeleton, invariably involving the shoulder girdle. Tumours within the subacromial space can cause secondary irritation of the rotator cuff and result in subacromial impingement syndrome.
We describe a 19 year old female patient with HME who presented with subacromial impingement syndrome secondary to a benign exostosis originating from the spine of the scapular and projecting into the subacromial space.
The unique aspects of this report was that the origin of the exostosis, which was not observed on early standard radiographs of the shoulder, and the use of arthroscopic excision of the exostosis. Hence we believe a low threshold for additional imaging, such as a magnetic resonance imaging, should be considered for patients with HME with subacromial impingement syndrome to ensure a symptomatic exostosis is not neglected. Arthroscopic excision of a benign subacromial exostosis is effective, offering a minimally invasive approach with relief of the patient’s symptoms.
Exostosis; Shoulder; Impingement; Arthroscopy
Although conversion of an osteochondroma to chondrosarcoma is a well-described rare occurrence, it is usually associated with syndromes such as multiple hereditary exostoses and is much more common after maturity. We present here a rare case of secondary pelvic chondrosarcoma arising from a solitary exostosis in a pediatric patient. An 11-year-old, otherwise healthy, female was referred to our clinic for evaluation of a pelvic mass detected on a radiograph. The radiographs obtained by the referring physician demonstrated a large lesion arising from the right superior pubic ramus, which was visible but not identified on an abdominal radiograph several years prior. Histopathologic analysis showed chondrosarcoma which was supported by an additional opinion to rule out chondroblastic osteosarcoma. The patient was treated with wide resection without adjuvant therapy and is doing well with no evidence of recurrence five years post-operatively. There have been only a few small case series describing chondrosarcoma in the pediatric patient. Even rarer are descriptions of secondary chondrosarcoma with only occasional cases reported as part of larger case series. Chondrosarcoma is a rare and difficult diagnosis in the pediatric patient. There is often considerable debate between chondrosarcoma and chondroblastic osteosarcoma, and the treatment implications of differentiating these diagnoses are of paramount importance.
We describe a patient in which an osteochondroma, which resulted from hereditary multiple exostoses, limited flexion of the proximal interphalangeal (PIP) joint at birth. The tumor grew over the original distal head of the proximal phalanx, and the early appearance of a second ossification center on the base of the middle phalanx was observed. The mass was removed surgically when the patient was 17 months old. There was an improvement in the range of motion at a follow-up evaluation 3 years later. The tumor shape and the growth of the affected PIP joint are examined in detail.
Hereditary multiple exostosis; Osteochondroma; Growth of tumor
Thoracoplasty in combination with spine fusion is an established method to address the rib cage deformity in idiopathic scoliosis. Most reports about thoracoplasty and scoliosis correction focused on Harrington or CD instrumentation. We report a retrospective analysis of 21 consecutive patients, who were treated with pedicle screw instrumentation for idiopathic thoracic scoliosis and concomitant thoracoplasty. Minimal follow up was 24 (24–75) months. Indication for thoracoplasty was clinical rib prominence of more than 15°. In average there was a 44% correction of clinical rib hump, from 18 (15–25°) to 10° (0–18°) (p<0.0001) and a 40% correction of radiological rib hump, from 15 (5–20°) to 9°(2–15°) (p<0.0001). The preoperative pulmonary function, accessed by forced vital capacity (FVC) and one-second forced expiratory volume (FEV1), remained unchanged at the last follow up. The distal end of fusion was the end vertebra of the curve in 83.3% and the end vertebra plus one in 16.7% of the patients. There was a 68% correction of instrumented primary thoracic curves, from 60 (45–85°) to 19°(5–36°) (p<0.0001), and a 45% correction of non-instrumented secondary lumbar curves, from 40 (28–60°) to 22°(8–38°) (p<0.0001). Apical vertebral rotation (AVR) of the thoracic curves improved 54%, from 24 (10–35°) to 11° (5–20°) (p<0.0001). The tilt of lowest instrumented vertebra (LIV) improved 68%, from 28 (20–42°) to 9°(3–20°) (p<0.0001). There was no significant change in sagittal profile of the spine. Analysis with SRS-24 questionnaire showed that the majority of the patients were very satisfied with the outcome. A matched control group (n=21) operated by the same surgeon with the same operation technique but without concomitant thoracoplasty was chosen for comparison. The scoliosis correction in the two groups was comparable. The patients without thoracoplasty had 37% spontaneous improvement of the clinical rib hump.
Idiopathic scoliosis; Thoracoplasty; Pedicle screw instrumentation; Pulmonary function
Thoracoscopically-assisted anterior spinal instrumentation is being used widely to treat adolescent idiopathic scoliosis (AIS). Recent studies have showed that screws placed thoracoscopically could counter the aorta or entrance into the spinal canal. There are a few studies defining the anatomic landmarks to identify the relationship between the aorta and the thoracic vertebral body using quantitative measurement for the sake of safe placement of thoracoscopic vertebral screw in anterior correction for AIS. The CT scanning from T4 to T12 in 64 control subjects and 30 AIS patients from mainland China were analyzed manually. Parameters to be measured included the angle for safety screw placement (α), the angle of the aorta relative to the vertebral body (β), the distance from the line between the left and the right rib heads to the anterior wall of the vertebral canal (a), the distance from the left rib head to posterior wall of the aorta (b), the vertebral body transverse diameter (c) and vertebral rotation (γ). No significant differences were found between the groups with respect to age or sex. Compared with the control group, α angle from T7 to T10, β angle from T5 to T10 and b value at T9, T10 were significantly lower in the scoliotic group. The a value was significantly lower in the scoliotic group. The c value showed no significant difference between the two groups. In conclusion, to place the thoracoscopic vertebral screw safely, at the cephalad thoracic spine (T4–T6), the maximum ventral excursion angle should decrease gradually from 20° to 5°, the entry-point of the screw should be close to the rib head. For apical vertebrae (T7–T9), the maximum ventral excursion angle increased gradually from 5° to 12°. At the caudal thoracic spine (T10–T12), the maximum ventral excursion angle increased, the entry-point should shift 3∼5 mm ventrally.
Aorta; Thoracic vertebrae; Anatomy; Thoracoscopy; Scoliosis
The three-dimensional nature of the idiopathic spinal deformity has been investigated in cadaveric specimens and patients with both idiopathic scoliosis and idiopathic kyphosis (Scheuermann's disease). In both scoliotic and kyphotic deformities the essential lesion lies in the sagittal plane with apical vertebral wedging. In idiopathic scoliosis there is an apical lordosis which being biomechanically unstable rotates to the side to produce a scoliotic deformity as a secondary component. In contradistinction the kyphotic wedging process of Scheuermann's disease is mechanically stable and any associated idiopathic type scoliosis occurs above and below the region of kyphosis. When an asymmetric lordosis is created in the growing New Zealand white rabbit, a progressive lordoscoliosis is readily produced and when the thoracic kyphosis is restored the scoliotic deformity shows evidence of regression and this forms the basis of physiological treatment. In 25 patients with idiopathic thoracic scoliosis the thoracic kyphosis has been restored and this leads to enhanced correction of the deformity in all three planes.
Congenital spinal vertebral anomalies may present with deformity resulting in congenital scoliosis and kyphosis. This leads to abnormal spinal growth. The latter when combined with associated rib fusions may impair normal thoracic cage development and resultant pulmonary hypoplasia. Most congenital scoliosis can be detected in utero by ultrasound scan or recognized in the neonatal period, but a few spinal defects can remain undetected.
Materials and Methods
In this Grand Round, we present the case of a 7-year-old girl with a severe scoliosis and thoracic insufficiency syndrome (TIS). 3D CT reconstruction imaging demonstrated a mixed picture of fusion and segmentation abnormalities. A marked kyphoscoliosis was demonstrated at the thoraco-lumbar junction. Via a left thoracotomy, anterior excision of intervertebral discs was performed together with, interbody fusion, and in situ stabilisation of the kyphosis with double allograft (femur) strut grafts.
This article highlights the features of congenital kypho-scoliosis and TIS. The difficulties of treating kyphosis when combined with TIS are discussed together with the limitations of current surgical techniques.
Thoracic insufficiency syndrome
Priority of neurological decompression was regarded as necessary for scoliosis patients associated with Chiari I malformation in order to decrease the risk of spinal cord injury from scoliosis surgery. We report a retrospective series of scoliosis associated with Chiari I malformation in 13 adolescent patients and explore the effectiveness and safety of posterior scoliosis correction without suboccipital decompression. One-stage posterior approach total vertebral column resection was performed in seven patients with scoliosis or kyphosis curve >90° (average 100.1° scoliotic and 97.1° kyphotic curves) or presented with apparent neurological deficits, whereas the other six patients underwent posterior pedicle screw instrumentation for correction of spinal deformity alone (average 77.3° scoliotic and 44.0° kyphotic curves). The apex of the scoliosis curve was located at T7–T12. Mean operating time and intraoperative hemorrhage was 463 min and 5,190 ml in patients undergoing total vertebral column resection, with average correction rate of scoliosis and kyphosis being 63.3 and 71.1%, respectively. Mean operating time and intraoperative hemorrhage in patients undergoing instrumentation alone was 246 min and 1,450 ml, with the average correction rate of scoliosis and kyphosis being 60.8 and 53.4%, respectively. The mean follow-up duration was 32.2 months. No iatrogenic neurological deterioration had been encountered during the operation procedure and follow-up. After vertebral column resection, neurological dysfunctions such as relaxation of anal sphincter or hypermyotonia that occurred in three patients preoperatively improved gradually. In summary, suboccipital decompression prior to correction of spine deformity may not always be necessary for adolescent patients with scoliosis associated with Chiari I malformation. Particularly in patients with a severe and rigid curve or with significant neurological deficits, posterior approach total vertebral column resection is likely a good option, which could not only result in satisfactory correction of deformity, but also decrease the risk of neurological injury secondary to surgical intervention by shortening spine and reducing the tension of spinal cord.
Scoliosis; Kyphosis; Chiari malformation; Adolescent; Corrective surgery
Understanding how to classify and quantify three-dimensional (3D) spinal deformities remains an open question in adolescent idiopathic scoliosis. The objective of this study was to perform a 3D manifold characterization of scoliotic spines demonstrating thoracic deformations using a novel geometric and intuitive statistical tool to determine patterns in pathological cases.
Personalized 3D reconstructions of thoracic (T)/lumbar (L) spines from a cohort of 170 Lenke Type-1 patients were analyzed with a non-linear manifold embedding algorithm in order to reduce the high-dimensionality of the data, using statistical properties of neighbouring spine models. We extracted sub-groups of the data from the underlying manifold structure using an unsupervised clustering algorithm to understand the inherent distribution and determine classes of pathologies which appear from the low-dimensional space.
For Lenke Type-1 patients, four clusters were detected from the low-dimensional manifold of 3D models: (1) normal kyphosis (T) with hyper-lordosis (L) and high Cobb angles (37 cases), (2) low kyphosis (T) and normal lordosis (L), with high rotation of plane of maximum curvature (55 cases), (3) hypo-kyphotic (T) and hyper-lordosis (L) (21 cases) and (4) hyper-kyphotic (T) with strong vertebral rotation (57 cases). Results show the manifold representation can potentially be useful for classification of 3D spinal pathologies such as idiopathic scoliosis and serve as a tool for understanding the progression of deformities in longitudinal studies.
Quantitative evaluation illustrates that the complex space of spine variability can be modeled by a low-dimensional manifold and shows the existence of an additional hyper-kyphotic subgroup from the cohort of 3D spine reconstructions of Lenke Type-1 patients when compared with previous findings on the 3D classification of spinal deformities.
Manifold embedding; Unsupervised clustering; 3D spine reconstruction; Adolescent idiopathic scoliosis; Classification