Jae Young Hong

Surgical correction and fusion using posterior-only pedicle screw construct for neuropathic scoliosis in patients with cerebral palsy: A three-year follow-up study

Study Design. It is a retrospective study of 52 neuromuscular scoliosis patients with cerebral palsy (CP). Objective. To determine the effectiveness and amount of correction using posterior-only pedicle screw construct. Summary of Background Data. Although there have been many reports in literature supporting the use of pedicle screw-only constructs for the correction of adolescent idiopathic scoliosis, similar studies have not been reported in patients with CP. Methods. We retrospectively evaluated outcomes of 52 neuropathic scoliosis patients (28 males and 24 females) with CP over minimum 2 years of follow-up. All patients underwent pedicle screw fixation without any anterior procedure for the correction. Pelvic fixation was done in 10 patients who had pelvis obliquity more than 15°. All coronal and sagittal parameters were noted after surgery and at final follow-up. Patient’s functional outcome was measured using modified Rancho Los Amigos Hospital system criteria. Complications were recorded from record sheets and any change in the ambulatory status was also recorded. Results. Mean age was 22 years at the time of operation and average follow-up was 36.1 month. Cobb’s angle was improved to 62.9% (P < 0.0001) from 76.8° to 30.1° after surgery and 31.5° at final follow-up. This correction of scoliosis (41%∼92%) was found to be statistically significant (P < 0.0001). Overall correction in pelvic obliquity was 56.2% from 9.2° before surgery to 4.0° after surgery which was 43.1% at final follow-up to 5.2°. Twenty-one patients (42%) improved their functional ability by grade 1 with 2 patients by grade 2. After the operation parent or caretakers of patients exhibited better sitting balance and nursing care. There were 32% complications in the series major being pulmonary. There were 2 perioperative deaths and 1 patient developed neurologic deficit due to screw impingement in canal, which was resolved after removal. Conclusion. We reported satisfactory coronal and sagittal correction with posterior-only pedicle screw fixation without higher complication rate in CP patients. Further long-term study is recommended to evaluate the success of pedicle screw in this population.

Surgical complications in neuromuscular scoliosis operated with posterior- only approach using pedicle screw fixation

BackgroundThere are no reports describing complications with posterior spinal fusion (PSF) with segmental spinal instrumentation (SSI) using pedicle screw fixation in patients with neuromuscular scoliosis.MethodsFifty neuromuscular patients (18 cerebral palsy, 18 Duchenne muscular dystrophy, 8 spinal muscular atrophy and 6 others) were divided in two groups according to severity of curves; group I (< 90°) and group II (> 90°). All underwent PSF and SSI with pedicle screw fixation. There were no anterior procedures. Perioperative (within three months of surgery) and postoperative (after three months of surgery) complications were retrospectively reviewed.ResultsThere were fifty (37 perioperative, 13 postoperative) complications. Hemo/pneumothorax, pleural effusion, pulmonary edema requiring ICU care, complete spinal cord injury, deep wound infection and death were major complications; while atelectesis, pneumonia, mild pleural effusion, UTI, ileus, vomiting, gastritis, tingling sensation or radiating pain in lower limb, superficial infection and wound dehiscence were minor complications. Regarding perioperative complications, 34(68%) patients had at least one major or one minor complication. There were 16 patients with pulmonary, 14 with abdominal, 3 with wound related, 2 with neurological and 1 cardiovascular complications, respectively. There were two deaths, one due to cardiac arrest and other due to hypovolemic shock. Regarding postoperative complications 7 patients had coccygodynia, 3 had screw head prominence, 2 had bed sore and 1 had implant loosening, respectively. There was a significant relationship between age and increased intraoperative blood loss (p = 0.024). However it did not increased complications or need for ICU care. Similarly intraoperative blood loss > 3500 ml, severity of curve or need of pelvic fixation did not increase the complication rate or need for ICU. DMD patients had higher chances of coccygodynia postoperatively.ConclusionAlthough posterior-only approach using pedicle screw fixation had good correction rate, complications were similar to previous reports. There were few unusual complications like coccygodynia.

Comparative analysis of clinical outcomes in patients with osteoporotic vertebral compression fractures (OVCFs): conservative treatment versus balloon kyphoplasty

BACKGROUND CONTEXT Most osteoporotic vertebral compression fractures (OVCFs) can be treated conservatively. Recently, kyphoplasty has become a common treatment for painful osteoporotic compression fractures and has shown numerous benefits, such as early pain control and height restoration of the collapsed vertebral body. In spite of being a simple procedure, numerous complications related to kyphoplasty have been reported. Moreover, there is limited evidence to support its superiority. PURPOSE To compare the clinical outcomes of patients with OVCF according to different treatment modalities and identify clinical risk factors related to failure of conservative treatment of OVCF. STUDY DESIGN A prospective study consisting of a review of case report forms. PATIENTS SAMPLE: We prospectively enrolled 259 patients who had one or two acute painful OVCFs confirmed by magnetic resonance imaging. All patients were treated conservatively in the initial 3 weeks. Kyphoplasty was performed in 91 patients who complained of sustained back pain and disability in spite of conservative treatment for the initial 3 weeks. OUTCOME MEASURES Pain score using visual analog scale (VAS) and the Oswestry Disability Index (ODI). METHODS Participants were stratified according to age, sex, level and number of fractures, bone mineral density, body mass index (BMI), collapse rates, and history of spine fractures. Pain scores using VASs were assessed at 1 week and at 1, 3, 6, and 12 months. RESULTS A total of 259 patients were enrolled, and 231 patients (82 of 91 patients in the kyphoplasty group [KP] and 149 of 168 patients in the conservative treatment group) completed the 1-year follow-up. About 65% of patients were treated successfully with conservative treatment. Risk factors for failure of 3 weeks of conservative treatment were older age (older than 78.5 years), severe osteoporosis (t score less than -2.95), overweight (BMI more than 25.5), and larger collapse rates (more than 28.5%). There were significant reductions in VAS and ODI scores in both groups at each follow-up assessment. At the first month, better clinical results were observed in KP. However, there were no significant differences in outcome measures between the two groups at 3, 6, or 12 months. Thirteen subsequent compression fractures (five in KP and eight in the conservative treatment group) occurred during the 1-year follow-up period. CONCLUSION Both treatments of OVCF showed successful clinical results at the end of the 1-year follow-up period. Kyphoplasty showed better outcomes in the first month only. Given these results, prompt kyphoplasty should not be indicated in the case of a patient with OVCF that has no risk factors for failure with conservative treatment. Rather, a trial of conservative, 3-week treatment would be beneficial.

Correlations of adolescent idiopathic scoliosis and pectus excavatum.

Study Design: Radiologic study of scoliosis in pectus excavatum patients. Objectives: To determine the relation between pectus excavatum deformity and adolescent idiopathic scoliosis (AIS). Summary of Background Data: AIS may be related to other whole body deformities, but few reports have addressed the relation between chest deformity and scoliosis. Methods: A total of 248 patients with a diagnosis of pectus excavatum were enrolled in this study. All study patients underwent whole spine anteroposterior radiographs and chest computed tomography. Severity and type of scoliosis and chest deformity were measured using radiographs, and relations between pectus deformity and AIS were analyzed. Results: Overall, 56 of the 248 study patients had scoliosis (Cobb angle >10 degrees)—a prevalence of 22.58%. The incidence of scoliosis was significantly higher in female patients (38.46%) (P=0.002), and Lenke type 1 predominated in pectus patients (48.2%, P<0.0001). Mean age was greater in the scoliosis group than in the nonscoliosis group (P<0.0001), and the asymmetry of pectus deformity was more prominent in the scoliosis group (P=0.007). However, pectus deformity severity was similar in the 2 groups (P=0.061). Furthermore, although the scoliosis group showed a higher proportion of female patients (P=0.002), the severities of chest and spinal deformities were similar in the 2 groups for both sexes (P=0.314, P=0.227). Conclusions: Pectus excavatum and AIS were found to have a high concomitant incidence. And, the age, sex, and type of disease were significantly different in the scoliosis and pectus excavatum groups. Surgeons should consider these relationships when deciding upon treatment in patients with chest and spinal deformities.

Intraoperative blood loss during different stages of scoliosis surgery: A prospective study

BackgroundThere are a number of reasons for intraoperative blood loss during scoliosis surgery based on the type of approach, type of disease, osteopenia, and patient blood profile. However, no studies have investigated bleeding patterns according to the stage of the operation. The objective of this prospective study was to identify intraoperative bleeding patterns in different stages of scoliosis surgery.MethodsWe prospectively analyzed the estimated blood loss (EBL) and operation time over four stages of scoliosis surgery in 44 patients. The patients were divided into three groups: adolescent idiopathic (group 1), spastic neuromuscular (group 2) and paralytic neuromuscular (group 3). The per-level EBL and operation times of the groups were compared on a stage-by-stage basis. The bone marrow density (BMD) of each patient was also obtained, and the relationship between per-level EBL and BMD was compared using regression analysis.ResultsPer-level operation time was similar across all groups during surgical stage (p > 0.05). Per-level EBL was also similar during the dissection and bone-grafting states (p > 0.05). However, during the screw insertion stage, the per-level EBL was significantly higher in groups 2 and 3 compared to group 1 (p < 0.05). In the correction stage, per-level EBL was highest in group 3 (followed in order by groups 2 and 1) (p < 0.05). Preoperative BMD indicated that group 3 had the lowest bone quality, followed by groups 2 and 1 (in order), but the preoperative blood indices were similar in all groups. The differences in bleeding patterns in the screw insertion and correction stages were attributed to the poor bone quality of groups 2 and 3. Group 3 had the lowest bone quality, which caused loosening of the bone-screw interface during the correction stage and led to more bleeding. Patients with a T-score less than -2.5 showed a risk for high per-level EBL that was nine times higher than those with scores greater than -2.5 (p = 0.003).ConclusionsWe investigated the blood loss patterns during different stages of scoliosis surgery. Patients with poor BMD showed a risk of blood loss nine times higher than those with good BMD.

Evaluation of the three-dimensional deformities in scoliosis surgery with computed tomography: efficacy and relationship with clinical outcomes.

Study Design. Prospective radiological and clinical study with scoliosis patients. Objective. To determine the pre- and postoperative differences in the three-dimensional (3D) parameters and relationships with the outcome in scoliosis surgery. Summary of Background Data. Despite a proven important role of the 3D deformities in scoliosis, it is warranted to confirm the efficacy of these measurements, which carry a cost burden and radiation hazard. Methods. Fifty adolescent idiopathic scoliosis patients who underwent correction surgery were enrolled in this study. Pre- and postoperative whole spine radiographs and computed tomography were performed. The vertebral rotation (VR), rib hump index (RH), sternal shift (SS) on computed tomography were measured at the level of the apex in each patient. In addition, the patients described the SRS 30 (scoliosis research society 30) and ODI (owestry disability index) score. And, the differences in the parameter and the relationships between the radiological and clinical outcomes were analyzed. Results. There was significant decrease in the coronal curvature, RH, and SS after surgery (P < 0.0001). In addition, the VR decreased postoperatively but that was not significant (P = 0.236). There were significant relationships between the parameters in the coronal curvature, VR, RH, and SS, pre- and postoperatively (P < 0.05). However, regarding the pre- and postoperative differences, only the changes in the SS were related to changes in the coronal curvature (P = 0.006). In addition, there were significant relationships between the parameters and outcomes. The changes in ODI were related to changes in the coronal curvature, VR, RH, and SS (P < 0.0001, P = 0.039, P < 0.0001, P = 0.019, respectively). However, the changes in the SRS was only related to the changes in SS (P < 0.0001). Conclusion. There were significant correlations between the VR, RH, and SS with the coronal curvature, pre- and postoperatively. In addition, there were significant correlations between the 3D deformities and outcomes. Computed tomography based measurements of 3D deformities can provide useful information in planning, and predicting the outcome of corrective surgery.

False negative and positive motor evoked potentials in one patient: is single motor evoked potential monitoring reliable method? A case report and literature review.

Study Design. A case report and literature review. Objective. To report a false negative and delayed positive motor-evoked potential (MEP) in 1 patient. Summary of Background Data. An unreliable MEP can result in fatal outcomes because surgeons have recently begun to depend on the MEP for intraoperative decision-making. Methods. We report a case of a false MEP during scoliosis surgery that showed false negative and positive MEPs during a series of operations. Results. A 23-year-old man with a history of spondyloepiphyseal dysplasia presented with severe kyphoscoliosis. The initial neurologic examination did not reveal any neurologic abnormalities. Surgical correction and fusion were performed with transcranial MEP monitoring. During the entire procedure, the MEP did not reveal any signs of cord injury. However, lower limb paralysis and paresthesia was observed when the patient awakened. After 2 additional surgical procedures to recover the neurologic deficit, the MEP did not show any signs of cord injury but the patients neurologic status had recovered slightly. At postoperative day 8, the neurologic status recovered, and a third operation was performed to fix the long rods. However, there were abnormal amplitudes in both lower limbs but the patients neurologic status was almost normal. Conclusion. From our experience of false negative and positive MEP in 1 patient, it is concluded that undesirable events can occur with use of MEP in scoliosis or other spinal surgery. Therefore, we warn the surgeons too heavily rely on the MEP monitoring, and propose a further prospective study as well as use of alternative method that can improve the reliability of single MEP.

The effects of spinal cord injury induced by shortening on motor evoked potentials and spinal cord blood flow: An experimental study in swine

BACKGROUND Spinal cord injury due to spinal shortening is disastrous, but the amount that the spine can be shortened without injury is unknown. We assessed spinal cord injury and changes in spinal cord blood flow after spinal shortening in swine. METHODS Ten pigs underwent pedicle screw instrumentation between T10 and T13 followed by a T11 and T12 vertebrectomy resulting in spinal shortening. Spinal cord function and spinal cord blood flow were monitored simultaneously with use of transcranial motor evoked potentials and laser Doppler flowmetry, respectively. A staged shortening procedure was performed: phase 1 resulted in no morphological change in the spinal cord, phase 2 resulted in buckling of the spinal cord, and phase 3 resulted in kinking of the spinal cord. After loss of motor evoked potential signals, which was considered to indicate spinal cord injury, the spinal instrumentation was tightened. The motor evoked potentials and spinal cord blood flow were monitored for an additional thirty minutes, and a wake-up test was then performed. Finally, a spinal cord specimen was obtained and evaluated histologically. RESULTS The motor evoked potential data demonstrated no evidence of spinal cord injury during phases 1 and 2. However, the signals were lost during phase 3, indicating spinal cord injury. The mean shortening was 35 ± 2.7 mm, which was similar to the mean vertebral body height at the thoracolumbar level (33.6 ± 1.9 mm), indicating that spinal cord injury resulted from shortening equivalent to the height of one vertebra. Spinal shortening did not cause injury if the amount of shortening was less than the mean segmental height of the entire spinal column (27.7 ± 1.6 mm for T1-L6). The spinal cord blood flow increased slightly (by 11.6% ± 20.6%) during phase 2, but decreased by 43.1% ± 11.4% during phase 3. The wake-up test performed after thirty minutes revealed no movement in the lower limbs. CONCLUSIONS Spinal shortening of =104.2% of one vertebral body height at the thoracolumbar level caused spinal cord injury, but shortening of =73.8% did not result in injury. swine.

Correlation of pelvic orientation with adult scoliosis.

Study Design Prospective analysis of elderly volunteers with adult scoliosis. Objectives To analyze the correlation between the sagittal pelvic parameters and adult scoliosis. Summary of Background Data There are little data on the relationship between the sagittal pelvic parameters and adult scoliosis. Methods The study group comprised 108 elderly volunteers (21 men and 87 women). All underwent anteroposterior and lateral radiographs of whole spine including hip joints. The participants were classified into 3 groups: normal (Cobb angle <10 degrees), low grade (Cobb angle 10 to 19 degrees), and high grade (Cobb angle ≥20 degrees). The radiographic parameters were magnitude, location and direction of curves, sacral slope, pelvic tilting, pelvic incidence, S1 overhang, thoracic kyphosis, lumbar lordosis, and C7 plumbline. Statistical analysis was performed to identify the significant differences between the groups. Analysis of variance and Pearson correlation coefficient were used to determine the significance. Results The mean age and Cobb angle of the participants was 73 years (range: 61 to 87 y), and 11.2 degrees (range: 0.3 to 36.3 degrees), respectively. There were no significant differences in the sacral slope, thoracic kyphosis, and lumbar lordosis between the 3 groups (P>0.05, analysis of variance). The mean pelvic tilting of the high-grade or low-grade groups was significantly higher than that of the normal group (P<0.0001, P=0.003, Tukey HSD post hoc test). The high-grade group had significantly higher pelvic incidence than either the low-grade or normal groups (P=0.016, P<0.0001), and the low-grade group had higher pelvic incidence than the normal group (P<0.0001). The high-grade or low-grade groups had a significantly higher S1 overhang than the normal groups (P<0.0001, P=0.002). Comparing the C7 plumbline, high-grade or low-grade groups had a significantly higher value than normal groups (P<0.0001, P=0.012). The pelvic incidence, pelvic tilting, and S1 overhang were significantly correlated with the magnitude of curvature (r=0.592, P=0.0001; r=0.434, P=0.0001; and r=0.461, P=0.0001, respectively). Conclusions There was a significant correlation between the sagittal pelvic parameters and adult scoliosis in elderly volunteers. There was a significant difference in the pelvic incidence between the normal, low-grade, high-grade adult scoliosis groups. The pelvic tilting and S1 overhang of the high-grade or low-grade groups were significantly higher than the normal group. These 3 parameters were also associated with the magnitude of curvature.

Epidural cement leakage through pedicle violation after balloon kyphoplasty causing paraparesis in osteoporotic vertebral compression fractures - a report of two cases

Kyphoplasty is advantageous over vertebroplasty in terms of better kyphosis correction and diminished risk of cement extravasations. Literature described cement leakage causing neurological injury mainly after vertebroplasty procedure; only a few case reports show cement leakage with kyphoplasty without neurological injury or proper cause of leakage. We present a report two cases of osteoporotic vertebral compression fracture treated with kyphoplasty and developed cement leakage causing significant neurological injury. In both cases CT scan was the diagnostic tool to identify cause of cement leakage. CT scan exhibited violation of medial pedicle wall causing cement leakage in the spinal canal. Both patients displayed clinical improvement after decompression surgery with or without instrumentation. Retrospectively looking at stored fluoroscopic images, we found that improper position of trocar in AP and lateral view simultaneously while taking entry caused pedicle wall violation. We suggest not to cross medial pedicle wall in AP image throughout the entire procedure and keeping the trocar in the center of pedicle in lateral image would be the most important precaution to prevent such complication. Our case reports adds the neurological complications with kyphoplasty procedure and suggested that along with other precautions described in the literature, entry with trocar along the entire procedure keeping the oval shape of pedicle in mind (under C-arm) will probably help to prevent such complications.