Tetsuya Ohara

Adjacent Segment Disease After Posterior Lumbar Interbody Fusion: Based on Cases With a Minimum of 10 Years of Follow-up.

Study Design. Retrospective case-controlled study. Objective. To investigate the incidence of adjacent segment degeneration (ASD) and the associated risk factors during a period of at least 10 years after posterior lumbar interbody fusion (PLIF). Summary of Background Data. ASD is a problematic sequelae after spinal fusion surgery. Few long-term follow-up studies have investigated ASD after PLIF; thus, magnetic resonance imaging (MRI) data available for the evaluation of postoperative changes associated with ASD are limited. Method. One hundred one patients were retrospectively enrolled. The minimum follow-up was 10 years after surgery. Preoperative and postoperative (2, 5, and 10 yr after surgery) Radiographs and MRI images were evaluated. Disc height, vertebral slip, and intervertebral angle were examined on radiographical images. Disc degeneration and spinal stenosis on MRI images were evaluated. Risk factors for developing early-onset radiographical ASD were evaluated using a multivariate logistic regression analysis. Result. The degenerative changes in disc height, vertebral slip, and intervertebral angle on radiographs 10 years after surgery were found in 12, 36, and 17 cases, respectively, at the cranial-adjacent level and in 3, 6, and 11 cases, respectively, at the caudal-adjacent level. Increased disc degeneration and spinal stenosis worsening were observed in 62 and 68 cases, respectively, at the cranial-adjacent level and in 25 and 12 cases, respectively, at the caudal-adjacent level on MRI 10 years after surgery. Ten patients (9.9%) required reoperation, and 80% of revision surgeries were performed more than 5 years after the initial surgery. High pelvic incidence was a risk factor for developing early-onset radiographical ASD. Conclusion. The majority of the reoperations for ASD were performed more than 5 years after the initial lumbar fusion surgery, although the progression of radiographical ASD began in the early postoperative period. A high degree of pelvic incidence was a risk factor for developing early-onset radiographical ASD. Obtaining appropriate lumbar lordosis in PLIF is important for preventing ASD. Level of Evidence: 4

Comparison of vertebral rotation corrected by different techniques and anchors in surgical treatment of adolescent thoracic idiopathic scoliosis.

Study Design Evaluation of radiographs and computed tomography in patients undergoing different surgical interventions for adolescent idiopathic scoliosis (AIS). Objective To compare the correction of vertebral rotation by different surgical techniques and/or anchors in the treatment of AIS. Summary of Background Data The technique and the technology used in the surgical treatment of AIS continue to evolve; there is little information about the comparison of the vertebral rotation correction of thoracic scoliosis by different surgical techniques and/or anchors. Methods A retrospective study was performed on 106 consecutive patients with AIS, who underwent selective thoracic fusion with different surgical techniques and/or anchors, including hooks, wires, and pedicle screws on the periapical concave side from a posterior approach and an anterior approach using screws. The selection criteria were as follows: younger than 20 years of age, thoracic scoliosis (Lenke type 1, 2, and 3), selected thoracic fusion, and a minimum 2-year follow-up period, whereas thoracic hyperkyphosis was excluded. The patients were classified into group A (anterior approach, n=27), group H (hooks, n=39), group S (screws, n=25), and group W (wires, n=15). The Cobb angle and apical vertebral rotation were evaluated by plain radiography and computed tomography, respectively, before and after surgery and after 2 years of follow-up. Results All 4 groups were matched for age, sex, preoperative major curve, and curve flexibility. In all groups, the coronal Cobb angle was significantly improved after surgery, without any significant differences between the 4 groups. The Rotation Angle midline values in group A, group H, and group S were significantly improved after 2 years of follow-up (P<0.01), but not for group W. Rotation Angle sagittal was significantly improved after 2 years only in group A. Classification of each group into 2 subgroups according to the flexibility index (>0.5 and <0.5) provided Rotation Angle sagittal values that demonstrated significant improvement postoperatively (P<0.01) for group A and group S subgroups with a flexibility index >0.5. Conclusions Compared with the use of hooks and the wires, vertebral rotation in AIS is effectively corrected by either the anterior approach or posterior pedicle screw fixation, especially in patients with more flexible scoliosis (a flexibility index >0.5).

Three-dimensional analysis of formation failure in congenital scoliosis.

Study Design. Morphologic analysis was performed by 3-dimensional (3D) CT in 75 patients with congenital scoliosis exhibiting formation failure. Objectives. The objectives of this study were to conduct 3D analysis of the morphology of spinal malformation and to elucidate the association between malformed vertebrae and adjacent vertebrae. Summary of Background Data. The morphology of spinal malformation has conventionally been evaluated by plain radiograph radiography. Although the usefulness of 3D CT has recently been reported, these reports have only demonstrated that this technique allows more detailed evaluation than plain radiography. Methods. We examined the morphology of the posterior components in spinal malformation of formation failure and evaluated the association between the anterior and posterior components by 3D CT. We clarified the morphologic variations of the posterior components in spinal malformation by dividing 75 cases of formation failure into solitary and multiple numbers of malformed vertebrae and into simple and complex modes of malformation between anterior and posterior components. Results. Thirty-three patients exhibited a single malformed vertebra in the entire spine (solitary malformation group), while the other 42 had multiple malformed vertebrae (total, 102 malformed vertebrae: multiple malformation group). The multiple malformation group consisted of 26 patients (57 malformed vertebrae) in whom the cause of scoliosis could be explained separately for each of the malformed vertebrae and 16 patients (45 malformed vertebrae) in whom the structure was complicated and the cause of scoliosis could not be explained for each of the malformed vertebra. Conclusion. There were morphologic variations of the posterior components of malformed vertebrae. A completely new complex malformation in which the mechanism of formation failure may differ from the conventionally proposed mechanisms was also found.

Preventive effect of artificial ligamentous stabilization on the upper adjacent segment impairment following posterior lumbar interbody fusion.

Study Design. A retrospective, comparative study. Objective. To assess the effects of soft stabilization with artificial ligamentous bands placed on the upper segment adjacent to posterior lumbar interbody fusion (PLIF) for prevention of transition syndrome compared with patients who underwent PLIF without soft stabilization. Summary of Background Data. Spine fusion increases mechanical stress and can cause other spinal problems adjacent to the fusion level. Soft stabilization using artificial ligamentous bands has been reported to decrease the flexion instability and this iatrogenic problems. There is no report concerning the effect of soft stabilization to transition syndrome following PLIF. Methods. In 225 patients undergoing L4/5 PLIF, 70 consecutive patients who were treated concomitantly with decompression of L3/4 with minimum 2-year follow-up were included. Thirty-five patients underwent soft stabilization of L3/4 (soft stabilization [S] group) with natural neutral concept rods, and 35 patients did not (decompression [D] group). Radiographic changes in the disc height, vertebral slip, intervertebral angle, range of motion, lumbar lordosis, and L3 tilt angle were measured. On magnetic resonance imaging (MRI), postoperative progression of the disc degeneration and spinal canal stenosis were evaluated. Results. In the S group, significant posterior intervertebral expansion on radiograph was less advanced at the final follow-up (P < 0.005). MRI images demonstrated less significant aggravation of disc degeneration (P < 0.001) and progression of adjacent stenosis (P < 0.01), at L3/4 in the S group. Adjacent intervertebral changes on MRI occurred relatively early after surgery, suggesting that changes were due to transition syndrome, but not age-related changes. Conclusion. These results demonstrated an effect of soft stabilization for the prevention of transition syndrome in lumbar spine fusion. Although the postoperative follow-up periods in this study were not sufficiently long to reach a definitive conclusion, intervertebral breakdown adjacent to the rigid spine fusion could be diminished by the application of soft stabilization.

Radiographic Adjacent Segment Degeneration at Five Years After L4/5 Posterior Lumbar Interbody Fusion With Pedicle Screw Instrumentation: Evaluation by Computed Tomography and Annual Screening With Magnetic Resonance Imaging.

Study Design:Retrospective clinical study. Objective:To investigate adjacent segment degeneration (ASD) at 5 years after L4/5 posterior lumbar interbody fusion with pedicle screw instrumentation and L4/5 decompression surgery using plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI), with the evaluation of annual changes on MRI. Summary of Background Data:Methods of evaluation have been inconsistent among studies of ASD. There is no report that ASD in the lumbar spine after posterior lumbar interbody fusion at the same level is thoroughly evaluated on radiographs, CT, annual MRI changes, and the impact of decompression procedures. Methods:ASD was evaluated in 52 patients. Disk height, vertebral slip, intervertebral angle, and intervertebral range of motion were examined on plain radiographs. Facet joint degeneration on CT and disk degradation and spinal stenosis on MRI were classified into categories, and facet sagittalization and tropism were measured on CT. The incidence of ASD was compared between the decompression procedures. Results:The radiographic changes observed in the study were defined as radiographic ASD (R-ASD) without reoperation, as no patient required reoperation. R-ASD was rarely detected by radiography. The incidences of facet joint degeneration, MRI-detected disk degeneration, and spinal stenosis at the L3/4 and L5/S1 levels were 21% and 23%, 27% and 17%, and 35% and 4%, respectively. Progressive disk degeneration at L3/4 was found significantly more frequently in patients with aggravation of facet degeneration (P<0.01); however, the severities of preoperative facet degeneration, facet sagittalization, and tropism were not associated with progressive disk degeneration or spinal stenosis. In annual MRI, most R-ASD cases were detected within 3 years after surgery. Patients who underwent L4 total laminectomy had significantly more frequent R-ASD compared with those who received bilateral fenestration at L4/5 (P<0.01). Conclusions:R-ASD was detected more frequently by CT and MRI compared with radiography. Preoperative facet joint degeneration and morphology were not always related to progressive disk degeneration or spinal stenosis. Annual MRI suggested that accelerated degeneration was due to lumbar spine fusion, rather than aging degeneration. Decompression with preservation of posterior connective components is recommended to prevent R-ASD.

Comparison of Surgical Outcomes Between Anterior Fusion and Posterior Fusion in Patients With AIS Lenke Type 1 or 2 that Underwent Selective Thoracic Fusion -Long-term Follow-up Study Longer Than 10 Postoperative Years.

Study Design. A retrospective comparative study. Objective. We compared the outcomes between patients treated either by selective thoracic anterior (ASF) or posterior spinal fusion (PSF), with a minimum 10-year follow-up. Summary of Background Data. A retrospective long-term follow-up study was conducted to compare PSF (P group) and ASF (A group) with Lenke type 1 or 2. There were no significant differences in the correction rate and incidence of degenerative discs (DDs) on the lumbar area. Loss of correction was greater in the A group. Methods. The inclusion criteria were female, AIS Lenke type 1 or 2, minimum 10-year follow-up, MRI check-up at 5 years and 10 years postop. The number of patients, age, and curve types at the time of surgery were matched in both groups. Complications, pulmonary function, and SRS-30 were also evaluated. Results. P group: adding-on (AO) occurred in 14 patients. Two patients demonstrated progression of scoliosis >5° during follow-up. Degenerative discs occurred in 43% of patients at 10 years postop. There were significant differences in the %VC and FVC before surgery and at the final visit (P < 0.05). A group: AO occurred in 16 patients. Eleven showed progression of scoliosis >5°. Degenerative disc was recognized in 53% of the patients. There was no significant difference in the pulmonary function. There was a significant difference in selfimage score in the SRS-30 between the two groups (P < 0.05). Conclusion. Correction of scoliosis was significantly better ASF than PSF immediately postop. Greater loss of correction occurred with ASF at postop 10 years. Although shorter segments could be fused by ASF, there was no significant difference in the incidence of DDs. Pulmonary function test results improved in the P group and were restored in the A group during the perioperative period.

Rubinstein-Taybi syndrome with scoliosis

Study DesignCase report.ObjectiveThe authors present the case of a 14-year-old boy with Rubinstein-Taybi syndrome (RSTS) presenting scoliosis.Summary of Background DataThere have been no reports on surgery for RSTS presenting scoliosis.MethodsThe patient was referred to our hospital for evaluation of a progressive spinal curvature. A standing anteroposterior spine radiograph at presentation to our hospital revealed an 84-degree right thoracic curve from T6 to T12, along with a 63-degree left lumbar compensatory curve from T12 to L4. We planned a two-staged surgery and decided to fuse from T4 to L4. The first operation was front-back surgery because of the rigidity of the right thoracic curve. The second operation of lumbar anterior discectomy and fusion was arranged 9 months after the first surgery to prevent the crankshaft phenomenon due to his natural course of adolescent growth. To avoid respiratory complications, the patient was put on a respirator in the ICU for several days after both surgeries.ResultsFull-length spine radiographs after the first surgery revealed no instrumentation failure and showed that the right thoracic curve was corrected to 31 degrees and the left lumbar curve was corrected to 34 degrees. No postoperative complications occurred after both surgeries.ConclusionsWe succeeded in treating the patient without complications. Full-length spine standing radiographs at one year after the second operation demonstrated a stable bony arthrodesis with no loss of initial correction.

Proximal Junctional Kyphosis Following Posterior Hemivertebra Resection and Short Fusion in Children Younger Than 10 Years.

Study Design: A retrospective study. Objective: To investigate whether proximal junctional kyphosis (PJK) or obvious proximal junctional angle (PJA) changes in the sagittal plane develops following short fusion in children younger than 10 years of age with congenital scoliosis, and to investigate the possible risk factors. Summary of Background Data: PJK following long spinal fusion in adolescents and adults is a serious postoperative complication. Although the same problem may occur in patients with early-onset scoliosis who have undergone spine fusion, few studies have been reported any relationship between PJK and spinal fusion in young children with congenital scoliosis. Materials and Methods: Thirty-seven children treated in a single institution between 1998 and 2010 were reviewed retrospectively. The inclusion criteria included (1) younger than 10 years of age at the time of operation; (2) simple congenital deformity; (3) hemivertebra treated by posterior hemivertebrectomy with short fusion at a maximum of 5 motion segments; and (4) minimum follow-up for 2 years. The PJA from the caudal endplate of the upper instrumented vertebra (UIV) to the cephalad endplate of the vertebra adjacent to the UIV, thoracic kyphosis (T5–T12), lumbar lordosis (T12–S1), global sagittal balance, and magnitude of scoliosis of the major curves and upper compensated curves were measured on lateral radiographs. PJK was defined by a PJA>10 degrees during the follow-up and at least 10 degrees greater than the preoperative or early postoperative measurement. Wilcoxon tests were performed for statistical analysis. Results: PJK occurred in 7 of 37 patients (18.9%), during an average of 4.5±3.2 years of follow-up (2–12 y). The UIV level of children with PJK was on T9 in 4 patients, and T11, T12, and L1 in 1. Screw malposition at UIV was confirmed by postoperative computed tomography images in 6 patients. Only 1 patient with a screw deviation did not develop PJK during the follow-up period. None of the patients with PJK was symptomatic, and no patients required revision surgery because of PJK. PJK occurred and progressed during the first 6 months after surgery followed by almost no progression or slight improvement in patients that could be followed up beyond 6 months postoperatively; in association with an increase of the lumbar lordosis. Conclusions: PJK occurred in pediatric patients with simple congenital deformities following hemivertebrectomy and short fusion. PJK was more common in patients with (1) greater immediately postoperative segmental kyphosis and PJA; (2) screw malposition on the UIV; and (3) hemivertebra located on the lower thoracic or the thoracolumbar region.

Scoliosis Associated With Airflow Obstruction Due to Endothoracic Vertebral Hump

Study Design. A retrospective clinical study of scoliosis-associated airflow obstruction due to endothoracic vertebral hump. Objective. The purpose of this study was to evaluate and present anatomical features of patients with scoliosis who showed airflow obstruction caused by endothoracic vertebral hump. Summary of Background Data. It is well known that severe scoliosis causes airflow restriction due to thoracic cage deformity. There have been few reports of clinical data and anatomical features on scoliosis associated with airflow obstruction due to endothoracic vertebral hump. Methods. The subjects were 6 patients. The diagnoses were idiopathic scoliosis in 3 patients, symptomatic scoliosis in 2 patients, and thoracogenic scoliosis in 1 patient. The radiological outcome, comorbidities, pre- and postoperative respiratory function, and surgical complication were analyzed. Results. Four patients had preoperative atelectasis on the convex side of the lower lobe and improved after the operations. All patients showed main thoracic curves and their apex was located at T7–T9. All patients had lordoscoliosis except 1, who demonstrated kyphosing scoliosis. The correction rate was 78% (62.8%–83.5%). Preoperative thoracic lordosis within the range of −5° to −47° was postoperatively corrected to a substantially normal kyphosis within the range of 9° to 24°. The average vital capacity, percent VC improved from 0.72 L (0.33–1.17 L) to 1.21 L (0.82–1.71 L) and 45.5% (37.3%– 50.8%) to 63.7% (41.0%–88.6%) relatively. Spine Penetration Index improved from 23% (18%–35%) to 16% (13%–19%). Endothoracic hump ratio improved from 1.34 (0.98–1.93) to 1.12 (0.86–1.28). Conclusion. Each patient with symptomatic scoliosis and thoracogenic scoliosis required relatively long periods of respiration management. Patients having lordoscoliosis with an apex located between T7 and T9 may develop airflow obstruction due to an endothoracic vertebral hump. Correction of lordoscoliosis through anterior and posterior approaches successfully improved endothoracic hump ratio and atelectasis in all patients.

The Effects of Spinal Fusion on Lumbar Disc Degeneration in Patients with Adolescent Idiopathic Scoliosis: A Minimum 10-Year Follow-Up

STUDY DESIGN Retrospective study. OBJECTIVES This study focused on patients with adolescent idiopathic scoliosis (AIS) who were followed up for more than 10 years, and assessed the influence of spinal balance on lumbar degenerative changes at distal unfused segments (DUS). SUMMARY OF BACKGROUND DATA Previous studies suggested that longer fusion segments may result in higher rates of occurrence of disc degeneration (DD) at unfused segments adjacent to the distal fused area. However, there are no existing studies that correlate the degree of DD to the location of lower instrumented vertebra (LIV) and the amount of the residual lumbar curve during the follow-up period. METHODS Radiologic measurements were recorded at the time of surgery, immediately after surgery, and 10 years after surgery. The Pfirrmann grading scale was used to rate the MR images of these patients. The presence of vertebral DD was also used to classify patients into DD+ and DD- groups. RESULTS 93 patients with AIS participated in this study. The average age at the time of surgery was 15.2 years; the average follow-up time was 154 months. DD was found in 45 patients (48%) and L5/S1 was the most common (40%) location in those patients. The L1 group experienced DD at a frequency of 34%, whereas the frequency increased with lower LIV placement. There was a significant difference between DD+ and DD- in age at the time of operation, the L4 tilt (pre Op. and post. 10 years), and the number of mobile segments. CONCLUSIONS Disc degeneration occurred in 48% of the patients at the time of postop. 10 years. Disc degeneration had a tendency to occur in patients with greater preoperative and postoperative 10 years L4 tilt angle and fewer mobile segments in the lower lumbar spine. LEVEL OF EVIDENCE Level III.