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Chang-Hyun Lee, Jaebong Lee, James D. Kang, Seung-Jae Hyun, Ki-Jeong Kim, Tae-Ahn Jahng, and Hyun-Jib Kim

OBJECT

Posterior cervical surgery, expansive laminoplasty (EL) or laminectomy followed by fusion (LF), is usually performed in patients with multilevel (≥ 3) cervical spondylotic myelopathy (CSM). However, the superiority of either of these techniques is still open to debate. The aim of this study was to compare clinical outcomes and postoperative kyphosis in patients undergoing EL versus LF by performing a meta-analysis.

METHODS

Included in the meta-analysis were all studies of EL versus LF in adults with multilevel CSM in MEDLINE (PubMed), EMBASE, and the Cochrane library. A random-effects model was applied to pool data using the mean difference (MD) for continuous outcomes, such as the Japanese Orthopaedic Association (JOA) grade, the cervical curvature index (CCI), and the visual analog scale (VAS) score for neck pain.

RESULTS

Seven studies comprising 302 and 290 patients treated with EL and LF, respectively, were included in the final analyses. Both treatment groups showed slight cervical lordosis and moderate neck pain in the baseline state. Both groups were similarly improved in JOA grade (MD 0.09, 95% CI −0.37 to 0.54, p = 0.07) and neck pain VAS score (MD −0.33, 95% CI −1.50 to 0.84, p = 0.58). Both groups evenly lost cervical lordosis. In the LF group lordosis seemed to be preserved in long-term follow-up studies, although the difference between the 2 treatment groups was not statistically significant.

CONCLUSIONS

Both EL and LF lead to clinical improvement and loss of lordosis evenly. There is no evidence to support EL over LF in the treatment of multilevel CSM. Any superiority between EL and LF remains in question, although the LF group shows favorable long-term results.

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Samuel Tobias, Chang-Hyun Kim, Gregory Kosmorsky, and Joung H. Lee

Object

Clinoidal meningiomas remain a major neurosurgical challenge. Surgery-related outcome has been less than desirable in the past, and little attention has been directed toward improving visual deficits. The authors advocate a skull base technique for the removal of these difficult tumors and describe its advantages in terms of improving extent of resection and enhancing overall outcome, particularly visual function.

Methods

A retrospective analysis was performed on data obtained in 26 consecutive patients with clinoidal meningiomas (including one patient with hemangiopericytoma) who underwent resection between June 1995 and January 2003. In 24 cases the skull base procedure involved extradural anterior clinoidectomy, optic canal unroofing, and optic sheath opening; in two cases a standard pterional craniotomy was performed. Fourteen of the 26 patients suffered significant preoperative visual deficits. All patients underwent thorough pre- and postoperative ophthalmological evaluations. The follow-up period ranged from 3 to 91 months (mean 42.3 months). Total resection was achieved in 20 patients (77%), and the majority (76.9%) of patients with preoperative visual impairment experienced significant improvement.

Conclusions

With the use of the skull base technique, total resection and excellent visual outcome may be achieved with minimal morbidity in most patients with clinoidal meningiomas.

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Jae Hwan Cho, Chang Ju Hwang, Young Hyun Choi, Dong-Ho Lee, and Choon Sung Lee

OBJECTIVE

Cervical sagittal alignment (CSA) is related to function and quality of life, but it has not been frequently studied in patients with adolescent idiopathic scoliosis. This study aimed to reveal the change in CSA following corrective surgery, compare the cervical sagittal parameters according to curve types, and assess related factors for postoperative aggravation of CSA.

METHODS

The authors studied 318 consecutive patients with adolescent idiopathic scoliosis who underwent corrective surgery at a single center. Occiput–C2 and C2–7 lordosis, C2–7 sagittal vertical axis (SVA), T-1 slope, thoracic kyphosis, and lumbar sagittal profiles were measured preoperatively and postoperatively. Scoliosis Research Society Outcomes Questionnaire (SRS-22) scores were used as clinical outcomes. Each radiological parameter was compared preoperatively and postoperatively according to curve types (double major, single thoracic, and double thoracic curves). Patients were grouped based on preoperative CSA: the lordotic group (group L) and the kyphotic group (group K). Each radiological parameter was compared between the groups. Related factors for postoperative aggravation of CSA were assessed using multivariate logistic analysis.

RESULTS

Of the total number of patients studied, 67.0% (213 of 318) and 54.4% (173 of 318) showed cervical kyphotic alignment preoperatively and postoperatively, respectively. C2–7 lordosis increased (from −5.8° to −1.1°; p < 0.001) and C2–7 SVA decreased (from 24.2 to 20.0 mm; p < 0.001) postoperatively regardless of curve types. Although group K showed improvement in C2–7 lordosis (from −12.7° to −4.8°; p < 0.001), group L showed no difference (from 9.0° to 6.9°; p = 0.115) postoperatively. Clinical outcomes were not related to the degree of cervical kyphosis in this cohort. C2–7 lordosis (p < 0.001) and pelvic tilt (p = 0.019) were related to postoperative aggravation of CSA.

CONCLUSIONS

Regardless of the trend of improvement in CSA, many patients (54.4%) still showed cervical kyphotic alignment postoperatively. C2–7 lordosis and C2–7 SVA improved postoperatively in all curve types. However, postoperative changes in C2–7 lordosis showed different results based on preoperative CSA, which could be related to T-1 slope and thoracic kyphosis. However, clinical outcomes showed no difference based on CSA in this study cohort. Greater C2–7 lordosis and proximal thoracic curve preoperatively were risk factors for postoperative aggravation of CSA (p < 0.001 and p = 0.019, respectively).

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Chang-Hyun Lee, Young Eun Kim, Hak Joong Lee, Dong Gyu Kim, and Chi Heon Kim

OBJECTIVE

Pedicle screw-rod–based hybrid stabilization (PH) and interspinous device–based hybrid stabilization (IH) have been proposed to prevent adjacent-segment degeneration (ASD) and their effectiveness has been reported. However, a comparative study based on sound biomechanical proof has not yet been reported. The aim of this study was to compare the biomechanical effects of IH and PH on the transition and adjacent segments.

METHODS

A validated finite element model of the normal lumbosacral spine was used. Based on the normal model, a rigid fusion model was immobilized at the L4–5 level by a rigid fixator. The DIAM or NFlex model was added on the L3–4 segment of the fusion model to construct the IH and PH models, respectively. The developed models simulated 4 different loading directions using the hybrid loading protocol.

RESULTS

Compared with the intact case, fusion on L4–5 produced 18.8%, 9.3%, 11.7%, and 13.7% increments in motion at L3–4 under flexion, extension, lateral bending, and axial rotation, respectively. Additional instrumentation at L3–4 (transition segment) in hybrid models reduced motion changes at this level. The IH model showed 8.4%, −33.9%, 6.9%, and 2.0% change in motion at the segment, whereas the PH model showed −30.4%, −26.7%, −23.0%, and 12.9%. At L2–3 (adjacent segment), the PH model showed 14.3%, 3.4%, 15.0%, and 0.8% of motion increment compared with the motion in the IH model. Both hybrid models showed decreased intradiscal pressure (IDP) at the transition segment compared with the fusion model, but the pressure at L2–3 (adjacent segment) increased in all loading directions except under extension.

CONCLUSIONS

Both IH and PH models limited excessive motion and IDP at the transition segment compared with the fusion model. At the segment adjacent to the transition level, PH induced higher stress than IH model. Such differences may eventually influence the likelihood of ASD.

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Chang-Hyun Lee, Tae-Ahn Jahng, Seung-Jae Hyun, Chi Heon Kim, Sung-Bae Park, Ki-Jeong Kim, Chun Kee Chung, Hyun-Jib Kim, and Soo-Eon Lee

OBJECTIVE

The Dynesys, a pedicle-based dynamic stabilization (PDS) system, was introduced to overcome the drawbacks of fusion procedures. Nevertheless, the theoretical advantages of PDS over fusion have not been clearly confirmed. The aim of this study was to compare clinical and radiological outcomes of patients who underwent PDS using the Dynesys system with those who underwent posterior lumbar interbody fusion (PLIF).

METHODS

The authors searched PubMed, Embase, Web of Science, and the Cochrane Database. Studies that reported outcomes of patients who underwent PDS or PLIF for the treatment of degenerative lumbar spinal disease were included. The primary efficacy end points were perioperative outcomes. The secondary efficacy end points were changes in the Oswestry Disability Index (ODI) and back and leg pain visual analog scale (VAS) scores and in range of motion (ROM) at the treated and adjacent segments. A meta-analysis was performed to calculate weighted mean differences (WMDs), 95% confidence intervals, Q statistics, and I2 values. Forest plots were constructed for each analysis group.

RESULTS

Of the 274 retrieved articles, 7 (which involved 506 participants [Dynesys, 250; PLIF, 256]) met the inclusion criteria. The Dynesys group showed a competitive advantage in mean surgery duration (20.73 minutes, 95% CI 8.76–32.70 minutes), blood loss (81.87 ml, 95% CI 45.11–118.63 ml), and length of hospital stay (1.32 days, 95% CI 0.23–2.41 days). Both the Dynesys and PLIF groups experienced improved ODI and VAS scores after 2 years of follow-up. Regarding the ODI and VAS scores, no statistically significant difference was noted according to surgical procedure (ODI: WMD 0.12, 95% CI −3.48 to 3.72; back pain VAS score: WMD −0.15; 95% CI −0.56 to 0.26; leg pain VAS score: WMD −0.07; 95% CI −0.47 to 0.32). The mean ROM at the adjacent segment increased in both groups, and there was no substantial difference between them (WMD 1.13; 95% CI −0.33 to 2.59). Although the United States is the biggest market for Dynesys, no eligible study from the United States was found, and 4 of 8 enrolled studies were performed in China. The results must be interpreted with caution because of publication bias. During Dynesys implantation, surgeons have to decide the length of the spacer and cord pretension. These values are debatable and can vary according to the surgeon's experience and the patient's condition. Differences between the surgical procedures were not considered in this study.

CONCLUSIONS

Fusion still remains the method of choice for advanced degeneration and gross instability. However, spinal degenerative disease with or without Grade I spondylolisthesis, particularly in patients who require a quicker recovery, will likely constitute the main indication for PDS using the Dynesys system.

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Chang-Hyun Lee, Hae-Won Koo, Seong Rok Han, Chan-Young Choi, Moon-Jun Sohn, and Chae-Heuck Lee

OBJECTIVE

De novo seizure following craniotomy (DSC) for nontraumatic pathology may adversely affect medical and neurological outcomes in patients with no history of seizures who have undergone craniotomies. Antiepileptic drugs (AEDs) are commonly used prophylactically in patients undergoing craniotomy; however, evidence supporting this practice is limited and mixed. The authors aimed to collate the available evidence on the efficacy and tolerability of levetiracetam monotherapy and compare it with that of the classic AED, phenytoin, for DSC.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were searched for studies that compared levetiracetam with phenytoin for DSC prevention. Inclusion criteria were adult patients with no history of epilepsy who underwent craniotomy with prophylactic usage of phenytoin, a comparator group with levetiracetam treatment as the main treatment difference between the two groups, and availability of data on the numbers of patients and seizures for each group. Patients with brain injury and previous seizure history were excluded. DSC occurrence and adverse drug reaction (ADR) were evaluated. Seizure occurrence was calculated using the Peto odds ratio (POR), which is the relative effect estimation method of choice for binary data with rare events.

RESULTS

Data from 7 studies involving 803 patients were included. The DSC occurrence rate was 1.26% (4/318) in the levetiracetam cohort and 6.60% (32/485) in the phenytoin cohort. Meta-analysis showed that levetiracetam is significantly superior to phenytoin for DSC prevention (POR 0.233, 95% confidence interval [CI] 0.117–0.462, p < 0.001). Subgroup analysis demonstrated that levetiracetam is superior to phenytoin for DSC due to all brain diseases (POR 0.129, 95% CI 0.039–0.423, p = 0.001) and tumor (POR 0.282, 95% CI 0.117–0.678, p = 0.005). ADRs in the levetiracetam group were cognitive disturbance, thrombophlebitis, irritability, lethargy, tiredness, and asthenia, whereas rash, anaphylaxis, arrhythmia, and hyponatremia were more common in the phenytoin group. The overall occurrence of ADR in the phenytoin (34/466) and levetiracetam (26/432) groups (p = 0.44) demonstrated no statistically significant difference in ADR occurrence. However, the discontinuation rate of AEDs due to ADR was 53/297 in the phenytoin group and 6/196 in the levetiracetam group (POR 0.266, 95% CI 0.137–0.518, p < 0.001).

CONCLUSIONS

Levetiracetam is superior to phenytoin for DSC prevention for nontraumatic pathology and has fewer serious ADRs that lead to discontinuation. Further high-quality studies that compare levetiracetam with placebo are necessary to provide evidence for establishing AED guidelines.

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Kyung Hyun Kim, Ji Yeoun Lee, Ji Hoon Phi, Seung-Ki Kim, Byung-Kyu Cho, and Kyu-Chang Wang

OBJECTIVE

The surgical indications for some arachnoid cysts (ACs) are controversial. While surgical procedures can be effective when an AC is a definite cause of hydrocephalus or papilledema, most ACs do not cause any symptoms or signs. Some surgeons perform several procedures to treat ACs because of their large size. The purpose of this study was to compare the long-term outcomes of Galassi type III ACs between surgery and nonsurgery groups.

METHODS

The medical records of 60 patients diagnosed with sylvian ACs (Galassi type III) who visited Seoul National University Children’s Hospital from July 1990 to March 2018 were analyzed. The authors compared the outcomes between those treated with surgery and those not treated with surgery.

RESULTS

Of the 60 patients, 27 patients had no symptoms, 19 patients had vague symptoms and signs associated with ACs, and the remaining 14 patients had definite AC-related symptoms and signs. Thirty-eight patients underwent surgery, and 22 patients underwent observation. Some operations were accompanied by complications. Among the 33 patients in the surgery group, excluding 5 with hydrocephalus or papilledema, 8 patients needed 18 additional operations. However, there were no patients in the nonsurgery group who needed surgical intervention during the follow-up period (mean 67.5 months), although the size of the AC increased in 2 patients. Changes in AC size were not correlated with symptom relief.

CONCLUSIONS

When patients with hydrocephalus or papilledema were excluded, there was no difference in the outcomes between the surgery and nonsurgery groups regardless of the size of the sylvian AC. Surgeons should be cautious when deciding whether to operate.

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Chang Kyu Lee, Dong Ah Shin, Seong Yi, Keung Nyun Kim, Hyun Chul Shin, Do Heum Yoon, and Yoon Ha

OBJECT

The goal of this study was to determine the relationship between cervical spine sagittal alignment and clinical outcomes after cervical laminoplasty in patients with ossification of the posterior longitudinal ligament (OPLL).

METHODS

Fifty consecutive patients who underwent a cervical laminoplasty for OPLL between January 2012 and January 2013 and who were followed up for at least 1 year were analyzed in this study. Standing plain radiographs of the cervical spine, CT (midsagittal view), and MRI (T2-weighted sagittal view) were obtained (anteroposterior, lateral, flexion, and extension) pre- and postoperatively. Cervical spine alignment was assessed with the following 3 parameters: the C2–7 Cobb angle, C2–7 sagittal vertical axis (SVA), and T-1 slope minus C2–7 Cobb angle. The change in cervical sagittal alignment was defined as the difference between the post- and preoperative C2–7 Cobb angles, C2–7 SVAs, and T-1 slope minus C2–7 Cobb angles. Outcome assessments (visual analog scale [VAS], Oswestry Neck Disability Index [NDI], 36-Item Short-Form Health Survey [SF-36], and Japanese Orthopaedic Association [JOA] scores) were obtained in all patients pre- and postoperatively.

RESULTS

The average patient age was 56.3 years (range 38–72 years). There were 34 male patients and 16 female patients. Cervical laminoplasty for OPLL helped alleviate radiculomyelopathy. Compared with the preoperative scores, improvement was seen in postoperative VAS and JOA scores. After laminoplasty, 35 patients had kyphotic changes, and 15 had lordotic changes. However, cervical sagittal alignment after laminoplasty was not significantly associated with clinical outcomes in terms of postoperative improvement of the JOA score (C2–7 Cobb angle: p = 0.633; C2–7 SVA: p = 0.817; T-1 slope minus C2–7 lordosis: p = 0.554), the SF-36 score (C2–7 Cobb angle: p = 0.554; C2–7 SVA: p = 0.793; T-1 slope minus C2–7 lordosis: p = 0.829), the VAS neck score (C2–7 Cobb angle: p = 0.263; C2–7 SVA: p = 0.716; T-1 slope minus C2–7 lordosis: p = 0.497), or the NDI score (C2–7 Cobb angle: p = 0.568; C2–7 SVA: p = 0.279; T-1 slope minus C2–7 lordosis: p = 0.966). Similarly, the change in cervical sagittal alignment was not related to the JOA (p = 0.604), SF-36 (p = 0.308), VAS neck (p = 0.832), or NDI (p = 0.608) scores.

CONCLUSIONS

Cervical laminoplasty for OPLL improved radiculomyelopathy. Cervical laminoplasty increased the probability of cervical kyphotic alignment. However, cervical sagittal alignment and clinical outcomes were not clearly related.

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Mijin Kim and Chang-Hyun Lee