The Efficacy of Proximal Lumbar Curve Flexibility in Patients with Main Thoracic Adolescent Idiopathic Scoliosis Treated by Selective Thoracic Fusion Surgery

STUDY DESIGN: Retrospective radiographic study. PURPOSE: To evaluate the efficacy of the proximal lumbar curve flexibility compared with the traditional whole lumbar curve flexibility in patients with main thoracic adolescent idiopathic scoliosis (MT-AIS). OVERVIEW OF LITERATURE: Traditionally the flexibility of the whole lumbar curve was measured, and the flexibility of the proximal lumbar curve was not analyzed in any study. METHODS: Twenty-eight MT-AIS patients treated by anterior selective thoracic fusion (STF) were evaluated after mean follow-up of 50.1 months (range, 25 to 116 months). The male : female ratio was in 5 : 23. The man age at surgery was 14 years and 8 months (range, 11.4 to 18.4 years). The lumbar curve was divided into the proximal and distal curves by the lumbar apex. RESULTS: The mean final correction rates (CR)/(flexibilities) of the MT, lumbar, proximal lumbar, and distal lumbar curves were 65.2%/(50.5%), 61.9%/(92.8%), 65.3%/(90.9%), and 36.4%/(134%), respectively. With the final lumbar CR, the lumbar flexibility (r = 0.267, p > 0.05) and the proximal lumbar flexibility (r = 0.327, p > 0.05) was similarly correlated. The mean lumbar CR was similar to the proximal lumbar CR (61.9% vs. 65.3%, p = 0.305). And the correlation between the flexibility and the CR was significant only in the proximal lumbar curve (r = 0.457, p 0.05) or the distal lumbar curve (r = 0.175, p > 0.05). CONCLUSIONS: The proximal lumbar curve flexibility may be an alternative method of measuring the lumbar flexibility in MT-AIS patients treated by STF.

Kyphotic Angle Progression of Thoracic and Thoracolumbar Tuberculous Spondylitis after Surgical Treatment: Comparison with Predicted Kyphosis Outcome after Conservative Treatment

STUDY DESIGN: Retrospective comparative study. PURPOSE: To compare the progression of the kyphotic angle (KA) in a surgically treated group with the predicted outcome of a conservatively treated group. OVERVIEW OF LITERATURE: Late onset kyphosis is a complication of tuberculous spondylitis making its prevention a major goal of surgery. METHODS: Twenty six consecutive patients underwent an anterior reconstruction and posterior instrumented fusion in conjunction with antituberculous chemotherapy. The mean follow up was 56 months (range, 28 to 112 months). The patients were divided into subgroups based on the involved region of the thoracic and the thoracolumbar spine, initial KA, and the initial vertebral body loss (VBL(x)). The predicted KA (KA(Pd)) was calculated using the formula, KA(Pd)=5.5+30.5 VBL(x), to predict the final gibbus deformity. Kyphotic angle progression (DeltaKA) based on the radiographic measurements after surgery (DeltaKA(R)), and the predicted outcome of conservative treatment (DeltaKA(P)) with chemotherapy were compared. RESULTS: Among the subgroups of the regions involved and initial KA, the DeltaKA was radiographically superior with a reduced amount of kyphogenesis in the surgery group than the predicted outcome of the conservatively treated patients (p0.05) with VBL(x)< or =0.5 in the VBL(x) subgroup. CONCLUSIONS: These results showed that in the VBL(x) subgroup, an initial VBL(x)< or =0.5 is an indication of conservative antituberculous chemotherapy without surgery.

Axial Plane Lumbar Responses after Anterior Selective Thoracic Fusion for Main Thoracic Adolescent Idiopathic Scoliosis

STUDY DESIGN: A retrospective radiographic study. PURPOSE: To evaluate the axial plane lumbar responses after anterior selective thoracic fusion (STF) in patients with main thoracic adolescent idiopathic scoliosis (MT-AIS). OVERVIEW OF LITERATURE: Anterior scoliosis surgery induces more MT derotation through disc preparation than posterior surgery. METHODS: Twenty-eight MT-AIS patients treated with STF were evaluated after a minimum follow-up (FU) of 2 years. The MT and lumbar coronal angles, as well as the MT and lumbar rotational angles at the most rotated vertebrae were measured. RESULTS: At the last FU, the MT coronal correction and derotation rates were 65% and 41%, respectively. The lumbar coronal correction rate was 61% but there was minimal lumbar derotation (2%). Nine cases were decompensated (coronal balance >10 mm). After surgery, the compensated and decompensated groups showed similar MT coronal and axial correction rates. During the FU, the MT and lumbar apecies rotated in the same direction (r=0.443). In addition, significant MT derotation occurred in the decompensated group with increasing lumbar rotational correction loss. At the last FU, while the MT coronal correction was similar between the two groups, there was more MT derotation in the decompensated group. Furthermore, the MT rotational change was strongly associated with the coronal C7 plumb line position (r=0.728). CONCLUSIONS: After anterior STF in patients with MT-AIS, the final MT derotation is strongly associated with the coronal C7 plumb line position. During the FU, the excessive MT derotation in the decompensated group was attributed to excessive lumbar rotational correction loss.

Senescence of Nucleus Pulposus Chondrocytes in Human Intervertebral Discs

STUDY DESIGN: Senescence-related markers were assessed in surgically obtained human nucleus pulposus (NP) specimens. PURPOSE: To demonstrate the mechanism and signaling pathway involved in the senescence of NP chondrocytes. OVERVIEW OF LITERATURE: The population of senescent disc cells has been shown to be increased in degenerated or herniated discs. However, the mechanism and signaling pathway involved in the senescence of NP chondrocytes are unknown. METHODS: We examined cell senescence markers [senescence-associated beta-galactosidase (SA-beta-gal), telomere length, telomerase activity, p53, p21, pRB and p16] and the hydrogen peroxide (H2O2) content in human NP specimens. RESULTS: The percentage of SA-beta-gal-positive NP chondrocytes increased with age, while the telomere length and telomerase activity declined. However, there was no significant correlation between age and H2O2 content. The NP specimens with grade III or IV degeneration showed significantly higher percentages of SA-beta-gal-positive NP chondrocytes than those with grade II degeneration. Immunohistochemistry showed that senescent NP chondrocytes in all specimens expressed p53, p21, and pRB, while a few NP chondrocytes in only two specimens expressed p16. CONCLUSIONS: The present study demonstrates that, with increasing age and advancing disc degeneration, senescent NP chondrocytes increase or accumulate in the NP. Furthermore, the telomere-based p53, p21, pRB pathway, rather than the stress-based p16, pRB pathway, plays a more important role in the senescence of NP chondrocytes in in vivo conditions. Our results suggest that prevention or reversal of senescence of NP chondrocytes can be a novel mechanism by which to prevent human disc degeneration.

Sagittal Plane Lumbar Responses after Anterior Selective Thoracic Fusion for Main Thoracic Adolescent Idiopathic Scoliosis

STUDY DESIGN: A retrospective radiographic study. PURPOSE: To verify the correlation of sagittal and coronal plane changes after selective thoracic fusion in main thoracic (MT) adolescent idiopathic scoliosis (AIS). OVERVIEW OF LITERATURE: Sagittal plane deformity is known to be essential in the evolution of scoliosis. METHODS: Twenty-eight MT AIS patients treated by anterior selective thoracic fusion were evaluated after minimal follow-up of two years. The unfused lumbar area was divided into proximal and distal parts by the lumbar apex in the coronal plane, and into proximal and distal lumbar lordosis by L2 in the sagittal plane. Surgical motion (the difference between preoperative and postoperative values) and follow-up motion (the difference between postoperative and the last follow-up values) were compared. RESULTS: Immediately after surgery, as thoracic kyphosis increased, lumbar lordosis decreased (r=0.734); proximal lumbar lordosis increased, and distal lumbar lordosis decreased. The proximal lumbar area was mobilized in the sagittal plane, and was straightened in the coronal plane. However, the distal lumbar area was stabilized in the sagittal plane, and showed resistant motion against MT translation in the coronal plane. The surgical motion was correlated to the follow-up motion, i. e., was regulated during follow-up, and the regulatory motion was more precise in the distal than proximal lumbar area in both sagittal and coronal planes. CONCLUSIONS: Sagittal and coronal motions were co-related; optimal sagittal motions were necessary for optimal coronal motions after anterior selective thoracic fusion for MT AIS. Proximal and distal lumbar motions were different for different roles; the proximal lumbar area played a role as a bumper to absorb the MT translatory force, and the distal lumbar area played a role of resistance against MT translation.