Riluzole attenuates neuropathic pain and enhances functional recovery in a rodent model of cervical spondylotic myelopathy.

Cervical spondylotic myelopathy (CSM) is the commonest cause of spinal cord impairment worldwide and despite surgical treatment, it is commonly associated with chronic neuropathic pain and neurological impairment. Based on data suggesting a key role of sodium and glutamate mediated cellular injury in models of spinal cord compression, we examined whether riluzole, a sodium channel/glutamate blocker, could improve neurobehavioral outcomes in a rat model of CSM. To produce chronic progressive compression of the cervical spinal cord, we used an established model of graded mechanical cord compromise developed in our laboratory. The chronic (8weeks) mechanical compression of the cervical spinal cord resulted in persistent mechanical allodynia and thermal hyperalgesia at 8weeks. Moreover, we found increased expression of phosphorylated NR1 and NR2B in the dorsal horns as well as astrogliosis and increased microglia expression in the dorsal horns after mechanical compression. Following daily systemic administration for 7weeks after the induction of compression, riluzole (8mg/kg) significantly attenuated forelimb and hindlimb mechanical allodynia and alleviated thermal hyperalgesia in the tail. Importantly, riluzole led to a decrease in swing phase duration, an increase in hind leg swing speed and an increase paw intensity in gait analysis. Riluzole also decreased the number of phosphorylated NR1 and phosphorylated NR2B positive cells in the dorsal horns and the microglia activation in the dorsal horns. Together, our results indicate that systemic riluzole administration during chronic cervical spinal cord compression is effective at protecting spinal cord tissue, preserving neurobehavioral function and alleviating neuropathic pain, possibly by decreasing NMDA receptor phosphorylation in astrocytes and by eliminating microglia activation. As such, riluzole represents a promising clinical treatment for CSM.

A novel experimental model of cervical spondylotic myelopathy (CSM) to facilitate translational research.

Cervical spondylotic myelopathy (CSM) is the most common form of spinal cord impairment in adults. However critical gaps in our knowledge of the pathobiology of this disease have limited therapeutic advances. To facilitate progress in the field of regenerative medicine for CSM, we have developed a unique, clinically relevant model of CSM in rats. To model CSM, a piece of synthetic aromatic polyether, to promote local calcification, was implanted microsurgically under the C6 lamina in rats. We included a sham group in which the material was removed 30s after the implantation. MRI confirmed postero-anterior cervical spinal cord compression at the C6 level. Rats modeling CSM demonstrated insidious development of a broad-based, ataxic, spastic gait, forelimb weakness and sensory changes. No neurological deficits were noted in the sham group during the course of the study. Spasticity of the lower extremities was confirmed by a significantly greater H/M ratio in CSM rats in H reflex recordings compared to sham. Rats in the compression group experienced significant gray and white matter loss, astrogliosis, anterior horn cell loss and degeneration of the corticospinal tract. Moreover, chronic progressive posterior compression of the cervical spinal cord resulted in compromise of the spinal cord microvasculature, blood-spinal cord barrier disruption, inflammation and activation of apoptotic signaling pathways in neurons and oligodendrocytes. Finally, CSM rats were successfully subjected to decompressive surgery as confirmed by MRI. In summary, this novel rat CSM model reproduces the chronic and progressive nature of human CSM, produces neurological deficits and neuropathological features accurately mimicking the human condition, is MRI compatible and importantly, allows for surgical decompression.

Surgical outcome of lumbar fusion surgery in patients with Parkinson disease.

STUDY DESIGN: Retrospective study. OBJECTIVES: To investigate the overall surgical outcome of lumbar fusion surgery in patients with Parkinson disease (PD). SUMMARY OF BACK GROUND DATA: Poor bone quality and muscular dysfunction are important clinical manifestations connected with musculoskeletal diseases in PD patients. These secondary changes caused by PD often result in spinal pathology, indicating spine operations for some patients with scoliosis, kyphosis, osteoporotic fracture, or degenerative spondylosis. However, little is known about the surgical outcome or prognosis of spine surgery in PD patients. METHODS: Lumbar fusion surgery was performed on 20 patients who had PD and degenerative spinal diseases. At the time of lumbar fusion surgery, the mean duration of PD, age, sex, the preoperative visual analog pain scale (VAS, 0 to 100 mm) for low back pain, Hoehn and Yahr staging, and other comorbidities were evaluated. Patients' postoperative clinical outcome was measured using the criteria of Kim and Kim and VAS for back pain. Radiographic assessment was made using plain films and a dynamogram. RESULTS: At the time of the spine surgery, Hoehn and Yahr staging of PD was from 1 to 2 in all patients. Only 1 patient had a satisfactory outcome; a good result according to Kim and Kim's criteria. The average postoperative VAS (mm) was 55.2, whereas the mean preoperative VAS (mm) was 53.9. Radiological assessment showed fusion status in 15 patients and probably no solid fusion mass in 5 patients. CONCLUSIONS: A poor surgical outcome would be inevitable because of the worsening of symptoms owing to the natural history of PD. Therefore, our current study suggested surgical indication should be exercised cautiously in the patients with PD and spinal stenosis.

Scoliosis imaging: what radiologists should know.

Scoliosis is defined as a lateral spinal curvature with a Cobb angle of 10° or more. This abnormal curvature may be the result of an underlying congenital or developmental osseous or neurologic abnormality, but in most cases the cause is unknown. Imaging modalities such as radiography, computed tomography (CT), and magnetic resonance (MR) imaging play pivotal roles in the diagnosis, monitoring, and management of scoliosis, with radiography having the primary role and with MR imaging or CT indicated when the presence of an underlying osseous or neurologic cause is suspected. In interpreting the imaging features of scoliosis, it is essential to identify the significance of vertebrae in or near the curved segment (apex, end vertebra, neutral vertebra, stable vertebra), the curve type (primary or secondary, structural or nonstructural), the degree of angulation (measured with the Cobb method), the degree of vertebral rotation (measured with the Nash-Moe method), and the longitudinal extent of spinal involvement (according to the Lenke system). The treatment of idiopathic scoliosis is governed by the severity of the initial curvature and the probability of progression. When planning treatment or follow-up imaging, the biomechanics of curve progression must be considered: In idiopathic scoliosis, progression is most likely during periods of rapid growth, and the optimal follow-up interval in skeletally immature patients may be as short as 4 months. After skeletal maturity is attained, only curves of more than 30° must be monitored for progression.

Association between bone mineral density and metabolic syndrome in postmenopausal Korean women.

BACKGROUND/AIMS: We investigated the relationship between bone mineral density (BMD) of the femur neck or lumbar spine and metabolic syndrome or its parameters in postmenopausal Korean women. METHODS: This study included 399 postmenopausal women, for whom the BMD of their L2s-L4s and femur necks were examined in association with metabolic syndrome. RESULTS: Subjects with metabolic syndrome had a higher BMD of the femur neck than those without metabolic syndrome when adjusted for age (0.85 +/- 0.09 vs. 0.82 +/- 0.12 g/cm(2), p = 0.011), while there was no statistical difference at lumbar spine. When adjusted for age and BMI, high-density lipoprotein cholesterol (HDL-C) was weakly and negatively correlated with BMD of the lumbar and femur neck (r = -0.107, p = 0.033; r = -0.111, p = 0.028 respectively). CONCLUSION: Metabolic syndrome was partly associated with higher BMD in our postmenopausal Korean women. Our study also showed that HDL-C levels were negatively associated with BMD of the lumbar spine and femur neck which means that subjects with lower HDL-C levels could have higher BMD. The results of our retrospective study revealed that metabolic syndrome could be associated with higher BMD in our postmenopausal Korean women.

Vascular injury in thoracolumbar spinal surgeries and role of angiography in early diagnosis and management.

STUDY DESIGN: A retrospective outcomes study. OBJECTIVE: To stress on the importance of early diagnosis with the help of angiography and proper treatment of vascular injuries occurring during thoracolumbar surgeries and to report our results. SUMMARY OF BACKGROUND DATA: Vascular injury is a rare but dangerous complication that can develop during thoracolumbar surgeries and if not treated properly then it can lead to severe complications including the death of the patient. METHODS: The patients included in this study were the ones who were suspected to have a possible vascular injury after a thoracolumbar surgery. Contrast enhanced computed tomography was performed for patients having clinical signs suggesting vascular injury. Among these patients, who were suspected to have active bleeding and major vessel injury on computed tomography were further subjected to angiography. RESULTS: Of the 10 cases included in the study, vascular injury was identified to be arterial in origin in 8 cases and venous in 3 cases. Among the 8 cases of identified arterial injury, angiography was performed in 4 cases, of which 3 were found to have active bleeding and were subjected to immediate intervention. Of the 4 cases in which angiography was not performed, 3 of them expired at variable postoperative periods. Complications developed in total 5 cases including 3 cases of mortality, 1 case of infection, and 1 case of cauda equina syndrome. CONCLUSIONS: The vascular injuries during thoracolumbar spinal surgeries need immediate and aggressive treatment. In arterial injuries, we can prevent serious consequences by subjecting the patient to an angiography as early as possible followed by a therapeutic embolization. In contrast, for venous injuries if hemostasis has been confirmed, then an immediate intervention may not be always required.

Comparison of mechanical motion profiles following instrumented fusion and non-instrumented fusion at the L4-5 segment.

PURPOSE: To investigate the difference in motion profiles between instrumented and non-instrumented fusion of the lumbar spine. METHOD: In vivo retrospective radiological analysis of dynamic (flexion-extension) lateral plain films was performed in different lumbar spine fusion types. Twenty-eight patients underwent lumbar fusion surgery at the L4/5 level. Fourteen patients underwent anterior fusion surgery without implantation, and the others underwent posterior instrumented fusion. Segmental angular motion was measured at the fused and adjacent levels using dynamic plain lateral film 2 years after operation. RESULTS: The anterior uninstrumented fusion group showed mean 2.0 degrees of segmental angular motion at the fused level compared with mean of 0.8 degrees in the posterior instrumented fusion group (P < 0.05). In contrast, at the proximal adjacent level, decreased angular motion (mean 7.7 degrees ) was noted in the anterior uninstrumented fusion group compared with mean 11.6 degrees in the posterior instrumented fusion group (P < 0.05). CONCLUSION: This study suggests that differing stiffness of fusion segments could cause different mechanical motion profiles at adjacent segments.

The incidence of new vertebral compression fractures in women after kyphoplasty and factors involved.

PURPOSE: To identify the incidence of new vertebral compression fractures in women after kyphoplasty and to analyze influential factors in these patients. MATERIALS AND METHODS: One hundred and eleven consecutive female patients with osteoporotic vertebral compression fractures (VCFs) underwent kyphoplasty at 137 levels. These patients were followed for 15.2 months postoperatively. For the survey of new vertebral compression fractures, medical records and x-rays were reviewed, and telephone interviews were conducted with all patients. RESULTS: During that time 20 (18%) patients developed new VCFs. The rate of occurrence of new VCFs in one year was 15.5% using a Kaplan-Meier curve. Body mass index (BMI), symptom duration and kyphoplasty level were the statistically significant factors between the patient groups both with and without new VCFs after kyphoplasty. In the comparison between the adjacent and remote new VCF groups, the adjacent new VCF group showed a larger amount of polymethyl methacrylate (PMMA) use during kyphoplasty (p<0.05). Before kyphoplasty, 9.9% of the patients had been prescribed medication for osteoporosis, and 93.7% of the patients started or continued medication after kyphoplasty. The development of new VCFs was affected by the number of vertebrae involved in the kyphoplasty. However, the lower incidence rate (15.5%) of new compression fractures might be due to a greater percentage (93.7% in our study) of patients taking anti-osteoporotic medication before and/or after kyphoplasty. CONCLUSION: When kyphoplasty is planned for the management of patients with osteoporotic VCFs, the application of a small amount of PMMA can be considered in order to lower the risk of new fractures in adjacent vertebrae. The postoperative use of anti- osteoporotic medication is recommended for the prevention of new VCFs.

The Thoracic Lordosis Correction Improves Sacral Slope and Walking Ability in Neuromuscular Scoliosis.

STUDY DESIGN: Retrospective study. OBJECTIVE: To report on neuromuscular patients with preserved walking ability, but forward bending of the body due to thoracic lordosis, and to suggest thoracic lordosis correction as the surgical treatment. SUMMARY OF BACKGROUND DATA: It is an established fact that lumbar lordosis or pelvic parameter is directly related to thoracic sagittal balance. However, the reverse relationship has not been fully defined yet. Loss of thoracic kyphosis results in positive sagittal balance, which causes walking difficulty. Neuromuscular patients with thoracic lordosis have not been reported yet, and there have been no reports on their surgical treatments. METHODS: This study analyzed 8 patients treated with thoracic lordosis correction surgery. Every patient was diagnosed with muscular dystrophy. In thoracic lordosis correction surgery, anterior release was performed in the first stage and posterior segmental instrumentation was performed in the second stage. Radiographic parameters were compared and walking ability was evaluated with gait analysis. All patients were classified according to the modified Rancho Los Amigos Hospital system preoperatively and 2 years postoperatively to evaluate functional ability. The average follow-up period was 2.9 years. RESULTS: Before surgery, the mean thoracic sagittal alignment was -2.1-degree lordosis, the mean Cobb angle and sacral slope increased to 36.3 and 56.6 degrees, respectively. The anterior pelvic tilt in gait analysis was 29.3 degrees. At last follow-up after surgery, the mean thoracic sagittal alignment changed to 12.6-degree kyphosis, and the Cobb angle and sacral slope decreased to 18.9 and 39.5 degrees, respectively. Lumbar lordosis and the sacral slope showed significant positive correlation (P<0.001). The improvement in thoracic lordosis showed a significant correlation to the preoperative flexibility of the major curve (P=0.028). The anterior pelvic tilt in gait analysis improved to 15.4 degrees. The functional ability improved in 2 (50%) of 4 patients in class 2 and maintained in remaining 6 patients 2 years after surgery. CONCLUSIONS: Thoracic lordosis correction surgery in neuromuscular scoliosis patients with thoracic lordosis improved the sacral slope in the standing position and the anterior pelvic tilt in gait. Sagittal imbalance was compensated by the spinopelvic mechanism, and back and hip extensor muscles seem to play a major role in this compensation.

Comparison of the predictive value of myelography, computed tomography and MRI on the treadmill test in lumbar spinal stenosis.

To date, there have been no prospective, objective studies comparing the accuracy of the MRI, myelo-CT and myelography. The purpose of this study is to compare the diagnostic and predictive values of MRIs, myelo-CTs, and myelographies. Myelographies with dynamic motion views, myelo-CTs, MRIs and exercise treadmill tests were performed in 35 cases. The narrowest AP diameter of the dural sac was measured by myelography. At the pathologic level, dural cross-sectional area (D-CSA) was calculated in the MRI and Myelo-CT. The time to the first symptoms (TAF) and the total ambulation time (TAT) were measured during the exercise treadmill test and used as the standard in the comparison of correlation between radiographic parameters and walking capacity. The mean D-CSA by CT was 58.3 mm(2) and 47.6 mm(2) by MRI. All radiographic parameters such as AP diameters and D-CSA have no correlation to TAF or TAT (p > 0.05). Our data showed no statistically significant differences in the correlation of the patients' walking capacity to the severity of stenosis as assessed by myelography, myelo-CT and MRI.

Soft tissue impingement syndrome of the ankle: diagnostic efficacy of MRI and clinical results after arthroscopic treatment.

BACKGROUND: Soft-tissue impingement syndrome is now increasingly being recognized as a significant cause of chronic ankle pain. The aim of this study was to investigate the diagnostic accuracy of contrast-enhanced, fat-suppressed, three-dimensional (3D), fast-gradient-recalled acquisition in the steady state with radio-frequency-spoiling (CE 3D-FSPGR) magnetic resonance imaging (MRI), and to evaluate the clinical outcome of arthroscopic treatment of soft-tissue impingement associated with the ankle trauma. METHODS: This study reviewed 38 patients who had preoperative MRI and arthroscopic treatment of chronic ankle pain after trauma. The CE 3D-FSPGR MRI was used to evaluate the chronic ankle pain, and the American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score was used to evaluate the clinical results after arthroscopic treatment. RESULTS: The CE 3D-FSPGR MRI showed a sensitivity of 91.9%, a specificity of 84.4%, and an accuracy of 87.5% in diagnosing synovitis and soft tissue impingement. All patients had excellent or good outcomes after arthroscopic debridement. CONCLUSION: The results of this study suggest that a preoperative fat-suppressed CE 3D-FSPGR MRI is highly beneficial in diagnosing synovitis and soft-tissue impingement and that arthroscopic debridement of the synovitis or soft-tissue impingement has a good clinical outcome.

Analysis of single nucleotide polymorphism in adolescent idiopathic scoliosis in Korea: for personalized treatment.

PURPOSE: The incidence of adolescent idiopathic scoliosis (AIS) has rapidly increased, and with it, physician consultations and expenditures (about one and a half times) in the last 5 years. Recent etiological studies reveal that AIS is a complex genetic disorder that results from the interaction of multiple gene loci and the environment. For personalized treatment of AIS, a tool that can accurately measure the progression of Cobb's angle would be of great use. Gene analysis utilizing single nucleotide polymorphism (SNP) has been developed as a diagnostic tool for use in Caucasians but not Koreans. Therefore, we attempted to reveal AIS-related genes and their relevance in Koreans, exploring the potential use of gene analysis as a diagnostic tool for personalized treatment of AIS therein. MATERIALS AND METHODS: A total of 68 Korean AIS and 35 age- and sex-matched, healthy adolescents were enrolled in this study and were examined for 10 candidate scoliosis gene SNPs. RESULTS: This study revealed that the SNPs of rs2449539 in lysosomal-associated transmembrane protein 4 beta (LAPTM4B) and rs5742612 in upstream and insulin-like growth factor 1 (IGF1) were associated with both susceptibility to and curve severity in AIS. The results suggested that both LAPTM4B and IGF1 genes were important in AIS predisposition and progression. CONCLUSION: Thus, on the basis of this study, if more SNPs or candidate genes are studied in a larger population in Korea, personalized treatment of Korean AIS patients might become a possibility.

The biomechanical effect of pedicle screws' insertion angle and position on the superior adjacent segment in 1 segment lumbar fusion.

STUDY DESIGN: A finite element analysis. OBJECTIVE: To investigate the association between the position of an inserted pedicle screw and the corresponding facet contact force or intradiscal pressure. SUMMARY OF BACKGROUND DATA: Although superior facet joint violation by pedicle screws is not an uncommon occurrence in instrumented lumbar fusion surgery, its actual biomechanical significance is not well understood. Furthermore, the association between the position of the pedicle screw and the stress on the corresponding disc/facet joint has yet to be investigated. METHODS: According to the positions of pedicle screws in L4 of the L4-L5 lumbar fusion, 4 L4-L5 fusion models were simulated. These models included the violation of both L3-L4 superior facet joints by pedicle screws (facet joint violation [FV] model), the nonencroachment of both L3-L4 superior facet joints by pedicle screws (facet joint preservation [FP] model), and the removal state of pedicle screws in the FV model (removal of violated pedicle screws [rFV] model). The facet joint contact [FC] model represented the scenario in which the pedicle screws did not encroach upon either facet joint but were inserted close to the L3-L4 facet joint surface. Moreover, the uninstrumented fusion [UF] model represented the uninstrumented L4-L5 fusion. In each scenario, the intradiscal pressures and facet contact forces at the L2-L3 and L3-L4 segments were analyzed under extension and torsion moments. RESULTS: The FV model yielded the greatest increases in facet contact force and intradiscal pressure at the L3-L4 segment under extension and torsion moments. Following the FV model, the increases in intradiscal pressure and facet contact force were the second highest in the FC model followed by the FP model. Furthermore, the rFV model represented prominent reductions of previously increased facet contact force and intradiscal pressure at the L3-L4 segment. CONCLUSION: In models of 1-segment lumbar fusion surgery, the positions of pedicle screws were closely linked with corresponding disc stresses and facet contact forces. However, even in cases of facet violation by pedicle screws, removal of the pedicle screw after fusion completion can reduce facet contract forces and disc stresses under both extension and torsional moments.

Changes in vitamin D status after surgery in female patients with lumbar spinal stenosis and its clinical significance.

STUDY DESIGN: A prospective cohort study. OBJECTIVE: To demonstrate the changes in vitamin D status after surgery in female patients with lumbar spinal stenosis (LSS), and its correlation with surgical outcomes. SUMMARY OF BACKGROUND DATA: In patients with LSS, general health including walking ability and nutritional status can be markedly improved by decompressive surgery. It can be hypothesized that such improvement may have a positive effect on their vitamin D status. METHODS: In total, 31 female patients who underwent decompression and instrumented posterolateral fusion for LSS were enrolled. Serum 25-hydroxyvitamin D (25-OHD) level was measured before the surgery and at 1 year postoperative visit. According to serum 25-OHD level, patients were classified into 3 groups: (1) deficient group, when 25-OHD level was less than 20 ng/mL (< 50 nmol/L); (2) insufficient group, when 25-OHD level was between 20 to 30 ng/mL (50 nmol/L ≤ 25-OHD < 75 nmol/L); (3) and normal group, when 25-OHD level was 30 ng/mL or more (≥ 75 nmol/L). The Oswestry Disability Index (ODI) score and health-related quality of life (EQ-5D) were compared according to the level of 25-OHD at 1 year postoperatively. RESULTS: Preoperatively, there were 20 patients in the deficient group, 11 patients in the insufficient group and no patient in the normal group. There were no differences in age, body mass index, preoperative ODI scores, preoperative EQ-5D index scores, and EQ-5D visual analogue scale scores between the 2 groups. Mean preoperative 25-OHD level was 15.8 ng/mL (range, 5.2-29.4 ng/mL) and increased to 19.5 ng/mL (range, 6.3-47.7 ng/mL) 1 year after surgery (P = 0.075). Significant increase of 25-OHD was noted only in the deficient group (P = 0.017). Postoperatively, there were 18 patients in the deficient group, 8 patients in the insufficient group, and 5 patients in the normal group. In the postoperative deficient group, postoperative ODI scores and EQ-5D index scores showed significantly worse outcomes than those in the other groups. The changes in serum 25-OHD level were significantly correlated with the changes in ODI scores (r = -0.580; P = 0.001) and with the changes in EQ-5D index scores (r = 0.379; P = 0.035). In all the groups, postoperative ODI scores (r = -0.665; P < 0.001) and EQ-5D index scores (r = 0.601; P < 0.001) were significantly correlated with postoperative 25-OHD level. CONCLUSION: Vitamin D deficiency was common in patients with LSS. However, vitamin D status was improved after decompressive surgery, and postoperative 25-OHD level was significantly correlated with surgical outcomes.

A spinal cord astrocytoma and its concurrent osteoblastic metastases at the time of the initial diagnosis: a case report and literature review.

Bone metastasis from a spinal cord astrocytoma has been reported only twice in the English medical literature. It is generally known that bone metastasis is found after the initial diagnosis with/without intervening surgery rather than being found at the time of the diagnosis of astrocytoma. The purpose of this article is to report for the first time a case of concurrent bone metastasis from a spinal cord astrocytoma at the time of diagnosing the spinal cord astrocytoma.

Pelvic obliquity in neuromuscular scoliosis: radiologic comparative results of single-stage posterior versus two-stage anterior and posterior approach.

STUDY DESIGN: retrospective comparative study (Level III). OBJECTIVE: to compare the operative results of posterior fusion and a 2-stage anterior L5-S1 fusion followed by posterior fusion in neuromuscular scoliosis patients with significant pelvic obliquity (PO). SUMMARY OF BACKGROUND DATA: PO in neuromuscular scoliosis is common and a challenging problem that affects proper sitting balance, necessarily addressing the deformity and proper maintenance of the correction. METHODS: a total of 54 patients with neuromuscular scoliosis and significant PO (>10°) were divided into 2 groups. Group 1 (n = 24) was operated on for posterior fusion and pelvic fixation. Group 2 (n = 30) included patients who were subjected to a first-stage procedure consisting of a lumbosacral junction release and fusion through a midline retroperitoneal approach and then a second-stage procedure of posterior fusion and pelvic fixation. Parameters measured included length of the follow-up, number of fusion levels, age at operation, forced vital capacity, operative time, estimated blood loss, and postoperative complications. Radiologic parameters measured before surgery, after surgery at the time of discharge, and at a final follow-up included Cobb angle, T1 translation, sitting pelvic obliquity (PO) in the frontal plane, C7 plumb line, thoracic kyphosis, lumbar lordosis, and sacral inclination angle in the sagittal plane. RESULTS: the correction of scoliosis was similar in both groups. The preoperative PO averaged 19.5° in Group I and 22.9° in Group II (P = 0.22), which corrected after surgery to 9.7° versus 7.4° (P = 0.23), respectively. Group II correction progressively improved significantly compared to Group I (7.0° vs. 11.6° at P = 0.046) at the latest follow-up. A 40.6% correction (mean correction = 7.9) in sitting PO in Group I compared to 70.7% correction (mean correction = 5.9°) in Group II was observed (P = 0.004). The average loss of correction of PO at the final follow-up was lesser in group II, but not statistically significant (P = 0.07). CONCLUSION: anterior fusion of the lumbosacral junction followed by posterior fusion provides superior correction and maintenance of PO in patients with neuromuscular scoliosis.

Value of preoperative pulmonary function test in flaccid neuromuscular scoliosis surgery.

STUDY DESIGN: Retrospective study. OBJECTIVE: To evaluate the prognostic value of preoperative pulmonary function test (PFT) for postoperative pulmonary complications and to identify the operability associated with severely decreased forced vital capacity (FVC) (<30%) status in flaccid neuromuscular scoliosis. SUMMARY OF BACKGROUND DATA: The preoperative PFT, especially more than 30% FVC, is known as a critical factor for the operability of flaccid neuromuscular scoliosis. But only one study reported that patients with pre-existing respiratory failure on nocturnal noninvasive ventilation can undergo an operation for deformity correction without mortality and severe complications. METHODS: A total of 74 patients (45 male and 29 female) presented with flaccid neuromuscular scoliosis. For all patients, preoperative PFTs were evaluated and subdivided into three groups (<30% FVC, 30%-50% FVC, and >50% FVC). Then postoperative pulmonary complications, pneumothorax, pneumonia, atelectasis, prolonged ventilator care in the intensive care unit (more than 72 hours), and postoperative tracheostomy were evaluated. RESULTS: Among these patients, 59 had muscular dystrophy; 5, spinal muscular atrophy; 2, cerebral palsy; and 8, others. The mean age at surgery was 16.8 years (range, 5-32 years). The mean preoperative Cobb angle was 54.6° (16°-135°). The overall postoperative pulmonary complication rate was 31% (23 complications in 74 patients). The less than 30% FVC group had 6 complications among 18 patients; the 30% to 50% FVC group had 7 complications among 18 patients; and the more than 50% FVC group had 10 complications among 38 patients. There were no deaths during the perioperative period. There is no statistical difference between the three groups (P = 0.6195). CONCLUSION: Patients with flaccid neuromuscular scoliosis can undergo an operation for deformity correction regardless of the severely decreased pulmonary function.

The quantitative assessment of risk factors to overstress at adjacent segments after lumbar fusion: removal of posterior ligaments and pedicle screws.

STUDY DESIGN: Finite element method. OBJECTIVE: To investigate the changes in the disc stress and range of motion (ROM) at adjacent segments after lumbar fusion based on whether or not pedicle screws are removed and whether or not the continuity of the proximal posterior ligament complex (PLC) is preserved. SUMMARY OF BACKGROUND DATA: The ablation of proximal PLC continuity and the presence of pedicle screws have been reported to affect the biomechanics at adjacent segments after lumbar fusion. However, there have been few studies regarding the quantitative assessment of their contribution to overstress at adjacent segments after lumbar fusion. METHODS: In the validated intact lumbar finite element model (L2-L5), four types of L3-L4 fusion models were simulated. These models included the preservation of the PLC continuity with pedicle screws (Pp WiP), the preservation of PLC continuity without pedicle screws (Pp WoP), the sacrifice of PLC with pedicle screws (Sp WiP), and the sacrifice of PLC without pedicle screws (Sp WoP). In each scenario, the ROM, maximal von Mises stress of discs, and the facet joint contract force at adjacent segments were analyzed. RESULTS.: Among the four models, the Sp WiP yielded the greatest increase in the ROM and the maximal von Mises stress of the disc at adjacent segments under four moments. Following the SP WiP, the order of increase of the ROM and the disc stress was Pp WiP, Sp WoP, and Pp WoP. Furthermore, the increase of ROM and disc stress at the proximal adjacent segment was more than at the distal adjacent segment under all four moments in each model. The facet joint contact was also most increased in the Sp WiP under extension and torsion moment. CONCLUSION: The current study suggests that the preservation of the PLC continuity or the removal of pedicle screws after complete fusion could decrease the stress at adjacent segments, and their combination could act synergistically.

Video-assisted thoracoscopic surgery plus lumbar mini-open surgery for adolescent idiopathic scoliosis.

PURPOSE: The objectives of this study are to describe the outcome of adolescent idiopathic scoliosis (AIS) patients treated with Video Assisted Thoracoscopic Surgery (VATS) plus supplementary minimal incision in the lumbar region for thoracic and lumbar deformity correction and fusion. MATERIALS AND METHODS: This is a case series of 13 patients treated with VATS plus lumbar mini-open surgery for AIS. A total of 13 patients requiring fusions of both the thoracic and lumbar regions were included in this study: 5 of these patients were classified as Lenke type 1A and 8 as Lenke type 5C. Fusion was performed using VATS up to T12 or L1 vertebral level. Lower levels were accessed via a small mini-incision in the lumbar area to gain access to the lumbar spine via the retroperitoneal space. All patients had a minimum follow-up of 1 year. RESULTS: The average number of fused vertebrae was 7.1 levels. A significant correction in the Cobb angle was obtained at the final follow-up (p = 0.001). The instrumented segmental angle in the sagittal plane was relatively well-maintained following surgery, albeit with a slight increase. Scoliosis Research Society-22 (SRS-22) scores were noted have significantly improved at the final follow-up (p < 0.05). CONCLUSION: Indications for the use of VATS may be extended from patients with localized thoracic scoliosis to those with thoracolumbar scoliosis. By utilizing a supplementary minimal incision in the lumbar region, a satisfactory deformity correction may be accomplished with minimal post-operative scarring.