Young Baeg Kim

Postoperative changes in paraspinal muscle volume: comparison between paramedian interfascial and midline approaches for lumbar fusion.

In this study, we compared the paramedian interfascial approach (PIA) and the traditional midline approach (MA) for lumbar fusion to determine which approach resulted in the least amount of postoperative back muscle atrophy. We performed unilateral transforaminal posterior lumbar interbody fusion via MA on the symptomatic side and pedicle screw fixation via PIA on the other side in the same patient. We evaluated the damage to the paraspinal muscle after MA and PIA by measuring the preoperative and postoperative paraspinal muscle volume in 26 patients. The preoperative and postoperative cross-sectional area, thickness, and width of the multifidus muscle were measured by computed tomography. The degree of postoperative paraspinal muscle atrophy was significantly greater on the MA side than on the contralateral PIA side (-20.7% and -4.8%, respectively, p<0.01). In conclusion, the PIA for lumbar fusion yielded successful outcomes for the preservation of paraspinal muscle in these 26 patients. We suggest that the success of PIA is due to less manipulation and retraction of the paraspinal muscle and further studies on this technique may help confirm whether less muscle injury has positive effects on the long-term clinical outcome.

Neuroprotective effect of ginseng total saponins in experimental traumatic brain injury.

In the present study, we investigated whether ginseng total saponins (GTSs) protect hippocampal neurons after experimental traumatic brain injury (TBI) in rats. A moderate-grade TBI was made with the aid of a controlled cortical impact (CCI) device set at a velocity of 3.0 m/sec, a deformation of 3.0 mm, and a compression time of 0.2 sec at the right parietal area for adult male Sprague-Dawley rats. Sham-operated rats that underwent craniectomy without impact served as controls. GTSs (100 and 200 mg/kg) or saline was injected intraperitoneally into the rats immediately post-injury. Twenty-four hours after the injury, the rats underwent neurological evaluation. Contusion volume and the number of hippocampal neurons were calculated with apoptosis evaluated by TUNEL staining. 24 hr post-injury, saline-injected rats showed a significant loss of neuronal cells in the CA2 region of the right hippocampus (53.4%, p<0.05) and CA3 (34.6%, p<0.05) compared with contralateral hippocampal region, a significant increase in contusion volume (34±8 µL), and significant increase in neurologic deficits compared with the GTSs groups. Treating rats with GTSs seemed to protect the CCI-induced neuronal loss in the hippocampus, decrease cortical contusion volume, and improve neurological deficits.

The fatty degeneration of lumbar paraspinal muscles on computed tomography scan according to age and disc level.

BACKGROUND CONTEXT Spinal degeneration can occur not only in the bone and disc but also in muscles. Fatty infiltration (FI) and decreased volume have been described as characteristic changes that occur in muscle degeneration. Many studies about the lumbar paraspinal muscles have been conducted on patients with spine problems. However, the natural changes of age-dependent degeneration in the paraspinal muscles have not been studied properly. PURPOSE The purpose of this study is to investigate age- and level-dependent changes of the lumbar paraspinal muscles in the population without lumbar spinal symptoms. STUDY DESIGN This study is a retrospective case-control study. PATIENT SAMPLE A total of 887 patients who underwent computed tomography scan for abdomen and pelvis (APCT) between January 2013 and December 2013 were enrolled. After excluding 237 patients with medical history of spine surgery, low back pain, myopathy, muscular dystrophy, infectious disease, vertebral fracture, and deformity, 650 patients were finally subjected to this study. OUTCOME MEASURE The patients were divided into three age groups: young (20-39 years old), middle (40-59 years old), and old (60-89 years old). The degree of FI was checked twice for multifidus muscle (MF), erector spinae muscle (ES), and psoas muscle (PS) at each disc level from L1 to S1 on APCT by two investigators. The FI was measured as the Hounsfield unit, a mean density (MD) on CT. METHODS The age differences were compared with the data of the young group, and the level differences were compared with the data of the L1-L2 level. Student t test and intraclass correlation coefficient were checked for statistical analysis. RESULTS The gender ratio was not significantly different among the groups. Comparing with the young group, the MD of MF significantly decreased at L5-S1 in the middle group (p<.05), and at L3-L4-L5-S1 in the old group (p<.05). The MD of ES was significantly decreased at all levels in the old group (p<.05) but not significant in the middle group. Comparing with the L1-L2 level, the MD of MF significantly decreased at L5-S1 in the middle group (p<.05) and at L4-L5-S1 in the old group (p<.05). The MD of ES was significantly decreased at L5-S1 in the young and middle groups (p<.05) and at L4-L5-S1 in the old group (p<.01) compared with those at L1-L2. According to the age- and level-dependent changes of MD in the MF and ES, there was a tendency of progressive increase of FI in the muscles with age, which seemed to start from L5-S1 and spread to the upper levels. The age-dependent fatty degeneration appeared wider in the ES than the MF. The level-dependent FI of the ES showed a similar pattern with the MF, but the change of the ES seemed to start earlier in age than the MF at the L5-S1. There was no significant MD change in the PS according to age and level. Intraobserver and interobserver reliabilities were both high across all of the muscles (0.86-0.94 and 0.83-0.92). CONCLUSIONS As a result, the degree of intramuscular fat infiltration seems to be affected by age, disc level, and muscle type. It seems to be more prominent in the extensor muscles, extending from lower to upper levels.

Development of a Rat Model of Graded Contusive Spinal Cord Injury Using a Pneumatic Impact Device

An animal model of spinal cord trauma is essential for understanding the injury mechanisms, cord regeneration, and to aid the development of new therapeutic modalities. This study focused on the development of a graded experimental contusion model for spinal cord injury (SCI) using a pneumatic impact device made in Korea. A contusive injury was made to the dorsal aspect of the cord. Three trauma groups were defined according to the impact velocity (IV). A control group (n=6), received laminectomy only. Group 1 (n=10), 2 (n=10), and 3 (n=10) had IVs of 1.5 m/sec, 2.0 m/sec, and 3.5 m/sec respectively. Functional assessments were made up to the 14th day after injury. The cord was removed at the 14th post-injury day and prepared for histopathologic examination. Significant behavioral and histopathological abnormalities were found in control and each trauma group. All trauma groups showed severe functional impairment immediately after injury but following different rates of functional recovery (Fig. 5). As the impact velocity and impulse increased, the depth of contusive lesion revealed to be profound the results show that the rat model reproduces spinal cord lesions consistently, has a distinctive value in assessing the effects of impact energy.

Direct Lateral Lumbar Interbody Fusion: Clinical and Radiological Outcomes

Objective According to the recent development of minimally invasive spinal surgery, direct lumbar interbody fusion (DLIF) was introduced as an effective option to treat lumbar degenerative diseases. However, comprehensive results of DLIF have not been reported in Korea yet. The object of this study is to summarize radiological and clinical outcomes of our DLIF experience. Methods We performed DLIF for 130 patients from May 2011 to June 2013. Among them, 90 patients, who could be followed up for more than 6 months, were analyzed retrospectively. Clinical outcomes were compared using visual analog scale (VAS) score and Oswestry Disability Index (ODI). Bilateral foramen areas, disc height, segmental coronal and sagittal angle, and regional sagittal angle were measured. Additionally, fusion rate was assessed. Results A total of 90 patients, 116 levels, were underwent DLIF. The VAS and ODI improved statistically significant after surgery. All the approaches for DLIF were done on the left side. The left and right side foramen area changed from 99.5 mm2 and 102.9 mm2 to 159.2 mm2 and 151.2 mm2 postoperatively (p<0.001). Pre- and postoperative segmental coronal and sagittal angles changed statistically significant from 4.1° and 9.9° to 1.1° and 11.1°. Fusion rates of 6 and 12 months were 60.9% and 87.8%. Complications occurred in 17 patients (18.9%). However, most of the complications were resolved within 2 months. Conclusion DLIF is not only effective for indirect decompression and deformity correction but also shows satisfactory mechanical stability and fusion rate.

Clinical and Radiological Outcomes of a New Cage for Direct Lateral Lumbar Interbody Fusion

Objective In Korea, direct lateral interbody fusion (DLIF) was started since 2011, using standard cage (6° lordotic angle, 18mm width). Recently, a new wider cage with higher lordotic angle (12°, 22mm) was introduced. The aim of our study is to compare the clinical and radiologic outcomes of the two cage types. Methods We selected patients underwent DLIF, 125 cases used standard cages (standard group) and 38 cases used new cages (wide group). We followed them up for more than 6 months, and their radiological and clinical outcomes were analyzed retrospectively. For radiologic outcomes, lumbar lordotic angle (LLA), segmental lordoic angle (SLA), disc angle (DA), foraminal height change (FH), subsidence and intraoperative endplate destruction (iED) were checked. Clinical outcomes were compared using visual analog scale (VAS) score, Oswestry disability index (ODI) score and complications. Results LLA and SLA showed no significant changes postoperatively in both groups. DA showed significant increase after surgery in the wide group (p<0.05), but not in the standard group. Subsidence was significantly lower in the wide group (p<0.05). There was no difference in clinical outcomes between the two groups. Additional posterior decompression was done more frequently in the wide group. Postoperative change of foraminal height was significantly lower in the wide group (p<0.05). The iED was observed more frequently in the wide group (p<0.05) especially at the anterior edge of cage. Conclusion The new type of cage seems to result in more DA and less subsidence. But indirect foraminal decompression seems to be less effective than standard cage. Intraoperative endplate destruction occurs more frequently due to a steeper lordotic angle of the new cage.

Comparison of transforaminal lumbar interbody fusion with direct lumbar interbody fusion: clinical and radiological results.

Objective The use of direct lumbar interbody fusion (DLIF) has gradually increased; however, no studies have directly compared DLIF and transforaminal lumbar interbody fusion (TLIF). We compared DLIF and TLIF on the basis of clinical and radiological outcomes. Methods A retrospective review was performed on the medical records and radiographs of 98 and 81 patients who underwent TLIF and DLIF between January 2011 and December 2012. Clinical outcomes were compared with a visual analog scale (VAS) and the Oswestry disability index (ODI). The preoperative and postoperative disc heights, segmental sagittal/coronal angles, and lumbar lordosis were measured on radiographs. Fusion rates, operative time, estimated blood loss (EBL), length of hospital stay, and complications were assessed. Results DLIF was superior to TLIF regarding its ability to restore disc height, foraminal height, and coronal balance (p<0.001). As the extent of surgical level increased, DLIF displayed significant advantages over TLIF considering the operative time and EBL. However, fusion rates at 12 months post-operation were lower for DLIF (87.8%) than for TLIF (98.1%) (p=0.007). The changes of VAS and ODI between the TLIF and DLIF were not significantly different (p>0.05). Conclusion Both DLIF and TLIF are less invasive and thus good surgical options for treating degenerative lumber diseases. DLIF has higher potential in increasing neural foramina and correcting coronal balance, and involves a shorter operative time and reduced EBL, in comparison with TLIF. However, DLIF displayed a lower fusion rate than TLIF, and caused complications related to the transpsoas approach.

Clinical Applications of the Tubular Retractor on Spinal Disorders

Tubular retractor system as a minimally invasive surgery (MIS) technique has many advantages over other conventional MIS techniques. It offers direct visualization of the operative field, anatomical familiarity to spine surgeons, and minimizing tissue trauma. With technical advancement, many spinal pathologies are being treated using this system. Namely, herniated discs, lumbar and cervical stenosis, synovial cysts, lumbar instability, trauma, and even some intraspinal tumors have all been treated through tubular retractor system. Flexible arm and easy change of the tube direction are particularly useful in contralateral spinal decompression from an ipsilateral approach. Careful attention to surgical technique through narrow space will ensure that complications are minimized and will provide improved outcomes. However, understanding detailed anatomies and keeping precise surgical orientation are essential for this technique. Authors present the technical feasibility and initial results of use a tubular retractor system as a minimally invasive technique for variaties of spinal disorders with a review of literature.

A Case of Myelopathy after Intrathecal Injection of Fluorescein

We present a case with seizure, confusion, hypesthesia and paraplegia after intrathecal injection of fluorescein. A 41-year-old man was admitted to our institution for the management of the CSF leakage. Intrathecal injection of fluorescein was performed and he complained of severe pain and numbness in the lower extremities at the end of the injection. Four hours later, he exhibited confusion, paraparesis and two episodes of generalized seizures. Two days later, he showed paraplegia and all sensory modalities below the T12 level were absent. Spine magnetic resonance imaging revealed myelopathic change in the lower thoracic spinal cord. There was no improvement of weakness and sensory deficits in lower extremity even 14 days after fluorescein injection. We speculated that thoracic myelopathy was associated with the intrathecal injection of fluorescein. In spite of its rarity, the complication after intrathecal injection of fluorescein could be serious. Thus, obtaining an informed consent with discussion with patient before the procedure is mandatory.

Long Term Effect on Adjacent Segment Motion after Posterior Cervical Foraminotomy

Objective Posterior cervical foraminotomy (PCF) is a motion-preserving surgical technique. The objective was to determine whether PCF alter cervical motion as a long-term influence. Methods Thirty one patients who followed up more than 36 months after PCF for cervical radiculopathy from January 2004 to September 2008 were enrolled in this study. The range of motion (ROM) of whole cervical spine, the operated segment, the cranial and the caudal adjacent segment were obtained. The clinical result and the change of ROMs were compared with those in the patients performed anterior cervical discectomy and fusion (ACDF) during the same period. Results In PCF group, the ROM of whole cervical spine had no significant difference in statistically at preoperative and last follow up. The operated segment ROM was significantly decreased from 11.02±5.72 to 8.82±6.65 (p<0.05). The ROM of cranial adjacent segment was slightly increased from 10.42±5.13 to 11.02±5.41 and the ROM of caudal adjacent segment was decreased from 9.44±6.26 to 8.73±5.92, however these data were not meaningful statistically. In ACDF group, the operated ROM was decreased and unlike in PCF group, especially the ROM of caudal adjacent segment was increased from 9.39±4.21 to 11.33±5.07 (p<0.01). Conclusion As part of the long-term effects of PCF on cervical motion, the operated segment motions decreased but were preserved after PCF. However, unlikely after ACDF, the ROMs of the adjacent segment did not increase after PCF. PCF, by maintaining the motion of the operated segment, imposes less stress on the adjacent segments. This may be one of its advantages.