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Keun-Ho Lee, Ki-Tack Kim, Yong-Chan Kim, Joong-Won Lee and Kee-Yong Ha

OBJECTIVE

The purpose of this study was to investigate the rate of and the risk factors for surgery-related complications demonstrated on radiography after pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis in patients with ankylosing spondylitis (AS).

METHODS

The authors retrospectively reviewed the medical records of 230 consecutive patients with thoracolumbar kyphosis due to AS who had undergone 1-level PSO at a single institution in the period from 2010 to 2017. The causes of surgery-related complications were divided into two types: surgical/technical failure and mechanical failure.

RESULTS

The patients consisted of 20 women and 210 men, with an average age of 43.4 years. The average follow-up period was 39.0 months. The preoperative sagittal vertical axis was 18.5 ± 69.3 cm, which improved to 4.9 ± 4.6 cm after PSO. Of the 77 patients (33.5%) who experienced minor or major surgery-related complications, 56 had complications related to surgical/technical failure (overall incidence 24.3%) and 21 had complications related to mechanical failure (overall incidence 9.1%). Fourteen patients (6.1%) underwent reoperation. However, among the 77 patients with complications, the rate of revision surgery was 18.2%. The most common radiological complications were as follows: sagittal translation in 24 patients, coronal imbalance in 20, under-correction in 8, delayed union in 8, and distal junctional failure and kyphosis in 8. The most common causes of reoperation were coronal imbalance in 4 patients, symptomatic malposition of pedicle screws in 3, and distal junctional failure in 3. Delayed union was statistically correlated with posterior sagittal translation (p = 0.007).

CONCLUSIONS

PSO can provide acceptable radiographic outcomes for the correction of thoracolumbar kyphosis in patients with AS. However, a high incidence of surgery-related complications related to mechanical failure and surgical technique can develop. Thorough radiographic investigation before and during surgery is needed to determine whether complete ossification occurs along the anterior and posterior longitudinal ligaments of the spine.

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Yong-Chan Kim, Ji Hao Cui, Ki-Tack Kim, Gyu-Taek Park, Keun-Ho Lee, Sung-Min Kim and Lawrence G. Lenke

OBJECTIVE

In this study, the authors’ goal was to develop and validate novel radiographic parameters that better describe total body sagittal alignment (TBSA).

METHODS

One hundred sixty-six consecutive operative spinal deformity patients were evaluated using full-body stereoradiographic imaging. Seven TBSA parameters were measured and then correlated to 6 commonly used spinopelvic measurements. TBSA measures consisted of 4 distance measures relating the cranial center of mass (CCOM) to the sacrum, hips, knees, and ankles, and 3 angular measures relating the CCOM to the hips, knees, and ankles. Furthermore, each TBSA parameter was correlated to patient-reported outcome (PRO) scores using the Oswestry Disability Index (ODI) and Scoliosis Research Society–22 (SRS-22) instruments. Thirty patients were randomly selected for inter- and intraobserver reliability testing of the TBSA parameters using intraclass correlation coefficients (ICCs).

RESULTS

All TBSA radiographic parameters demonstrated strong linear correlation with the currently accepted primary measure of sagittal balance, the C7 sagittal vertical axis (r = 0.55–0.96, p < 0.001). Moreover, 5 of 7 TBSA measures correlated strongly with ODI and SRS-22 total scores (r = 0.42–0.51, p < 0.001). Inter- and intraobserver reliability for all TBSA measures was good to excellent (interrater ICC = 0.70–0.98, intrarater ICC = 0.77–1.0).

CONCLUSIONS

In spine deformity patients, novel TBSA radiographic parameters correlated well with PROs and with currently utilized spinal sagittal measurements. Inter- and intrarater reliability was high for these novel parameters. This is the first study to propose a reliable method for measuring head-to-toe global spinal alignment.

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Young Mi Yoo, Yong Jung Kim, Uhn Lee, Doo Jin Paik, Hyun Tae Yoo, Cheol Wan Park, Young Bo Kim, Sang Goo Lee, Woo Kyung Kim and Chan Jong Yoo

Object

Parkinson disease (PD) is a well-known degenerative disease resulting in the depletion of dopamine-producing neurons in the pars compacta of the substantia nigra. Adenoviral vector delivery of neurotrophic factors may provide a potential therapy for PD. The authors examined whether glial cell line–derived neurotrophic factor (GDNF) delivered via adenoviral vector (Ad-GDNF) could promote functional recovery in a rat model of PD. Additionally, they examined whether neural precursor cells (NPCs) provide the therapeutic potential of cultured neural cells for cell regeneration and replacement in PD.

Methods

All animals underwent stereotactic injection of 6-hydroxydopamine into the right substantia nigra. Eight weeks later, the rats were tested for apomorphine-induced rotational asymmetry and evaluation of explanted grafts infected with the complementary DNA for GDNF containing NPCs and NPCs alone. In the NPC cultures of embryonic rat striata, the authors found that basic fibroblast growth factor induced the proliferation of stem cells, which give rise to spheres of undifferentiated cells that generate neurons and glia.

Conclusions

In this study the authors found that the reduction of apomorphine-induced rotation was more prominent in parkinsonian rats that received Ad-GDNF-treated grafts containing NPCs (61%) than in those that received grafts of NPCs alone (16%).

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Jung Hee Kim, Yun-Sik Dho, Yong Hwy Kim, Jung Hyun Lee, Ji Hyun Lee, A. Ram Hong and Chan Soo Shin

OBJECTIVE

The natural history and proper algorithm for follow-up testing of nonfunctioning pituitary adenomas (PAs) are not well known, despite their relatively high prevalence. The aim of this study was to suggest the optimal follow-up algorithm for nonfunctioning PAs based on their natural history.

METHODS

The authors followed up 197 patients with nonfunctioning PAs that had not been treated (including surgery and radiation therapy) at the time of detection, in a single center, between March 2000 and February 2017. They conducted a hormone test, visual field test, and MRI at the time of diagnosis and yearly thereafter.

RESULTS

The overall median follow-up duration was 37 months. Microadenomas (n = 38) did not cause visual disturbance, pituitary apoplexy, or endocrine dysfunction. The incidence of patients with tumor volume growth ≥ 20% was higher for macroadenomas than microadenomas (13.8 vs 5.0 per 100 person-years [PYs], p = 0.002). The median time to any tumor growth was 4.8 years (95% CI 3.4–4.8 years) for microadenomas and 4 years (95% CI 3.3–4.2 years) for macroadenomas. The overall incidence of worsening visual function was 0.69 per 100 PYs. Patients with a tumor volume growth rate ≥ 0.88 cm3/year (n = 20) had a higher incidence of worsening visual function (4.69 vs 0.30 per 100 PYs, p < 0.001). The tumor growth rate of all microadenomas was < 0.88 cm3/year. The median time to tumor growth ≥ 20% was 3.3 years (95% CI 1.8–3.9 years) in patients with a tumor growth rate ≥ 0.88 cm3/year and 4.9 years (95% CI 4.6–7.2 years) in patients with a tumor growth rate < 0.88 cm3/year.

CONCLUSIONS

The authors have devised a follow-up strategy based on the tumor volume growth rate as well as initial tumor volume. In patients with microadenomas, the next MRI study can be performed at 3 years. In patients with macroadenomas, the second MRI study should be performed between 6 months and 1 year to assess the tumor growth rate. In patients with a tumor growth rate ≥ 0.88 cm3/year, the MRI study should be performed within 2 years. In patients with a tumor growth rate < 0.88 cm3/year, the MRI study can be delayed until 4 years.

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Zang-Hee Cho, Hoon-Ki Min, Se-Hong Oh, Jae-Yong Han, Chan-Woong Park, Je-Geun Chi, Young-Bo Kim, Sun Ha Paek, Andres M. Lozano and Kendall H. Lee

Object

A challenge associated with deep brain stimulation (DBS) in treating advanced Parkinson disease (PD) is the direct visualization of brain nuclei, which often involves indirect approximations of stereotactic targets. In the present study, the authors compared T2*-weighted images obtained using 7-T MR imaging with those obtained using 1.5- and 3-T MR imaging to ascertain whether 7-T imaging enables better visualization of targets for DBS in PD.

Methods

The authors compared 1.5-, 3-, and 7-T MR images obtained in 11 healthy volunteers and 1 patient with PD.

Results

With 7-T imaging, distinct images of the brain were obtained, including the subthalamic nucleus (STN) and internal globus pallidus (GPi). Compared with the 1.5- and 3-T MR images of the STN and GPi, the 7-T MR images showed marked improvements in spatial resolution, tissue contrast, and signal-to-noise ratio.

Conclusions

Data in this study reveal the superiority of 7-T MR imaging for visualizing structures targeted for DBS in the management of PD. This finding suggests that by enabling the direct visualization of neural structures of interest, 7-T MR imaging could be a valuable aid in neurosurgical procedures.