Adjacent Segment Instability after Posterior Lumbar Fusion: Comparison Between Subtotal Laminectomy and Total Laminectomy

OBJECTIVE: Whereas fusion with pedicle screw fixation has shown satisfactory clinical results, solid fusion has been reported to accelerate degenerative changes in adjacent unfused levels. The purpose of this study was to evaluate the effect of bone/ligament/bone integrity after subtotal or total laminectomies on the development of adjacent segment instability (ASI). The hypothesis that total laminectomy would increase ASI more than would subtotal laminectomy was analyzed. Material and METHODS: This is a retrospective study of 316 patients who were treated with posterior fusion and pedicle screw fixation between 1996 and 2001. After attempts to review all 316 patients and radiologic files, 36 patients who were diagnosed with ASI were carefully reviewed, including follow-up periods of 2-8 years. The medical records were carefully reviewed for recurrence of low back pain or neurologic symptoms after a period of postoperative relief, and the radiologic files were evaluated to determine instability. All patients had undergone single-level or multilevel instrumented posterior lumbar interbody fusion for intractable pain related to degenerative conditions of the spine. RESULTS: Patients over the age of 60 were at a higher risk of developing clinical ASI however,fusion length, level and gender were not associated with ASI. The ASI was noted to occur most commonly in the cranial segment prior to fusion. CONCLUSIONS: This study revealed more frequent ASI after total laminectomy than after subtotal laminectomy, especially in elderly patients. The ideal procedure will be one combining maximal canal and foraminal decompressions with minimal resection of bony structures and supporting ligaments.

Ultrastructural Differences between Inner and Outer Layers of Human Lumbar Ligamentum Flavum

No abstract available.

Outcome Comparison of Instrumented Posterolateral Fusion and Posterior Lumbar Interbody Fusion with Cages for Surgical Management of Lumbar Spondylolisthesis in Adults

For the primary fusion of adult's lumbar spondylolisthesis the authors performed either posterolateral fusion(PLF) with transpedicular screw fixation, or posterior lumbar interbody fusion(PLIF) with cages and transpedicular screw fixation, on 75 patients during five years between Jan. 1993 and Dec. 1997. The outcomes were retrospectively reviewed with emphasis on comparison of the results of these two surgical methods. Between patients treated with PLF(PLF group) and PLIF(PLIF group) there were no differences in distribution of preoperative variables such as patients' age and gender, type, level, grade of spondylolisthesis, and symptom durations. Mean follow-up period was 22.3 months in PLF group(n=44) and 17.4 months in PLIF group(n=31) (p<0.001). The rate of fusion was 85% in PLF group, and 94% in PLIF group(p=0.292). The postoperative outcome, expressed as mean follow-up score of Prolo scale, was 6.86 in PLF group and 7.42 in PLIF group(p=0.007). The variables that were associated with the outcomes were the level of spondylolisthesis(p=0.001) and the type of fusion (p=0.023). Variables such as age, gender, type and grade of spondylolisthesis, preoperative symptom duration, radiological findings of fusion status, change in disc height, and change in sagittal angle were not associated with the outcomes. The complication rate was 11% in PLF group and 19% in PLIF group. Overall successful results, defined by 7 or more in follow-up score of Prolo scale, were seen in 68% of PLF group and 87% of PLIF group(p=0.098). It is concluded that better surgical outcomes were obtained by PLIF methods in adults with lumbar spondylolisthesis, but with regards to the incidence of complications, although mostly minor and reversible, was more frequent in PLIF group.

The Changes of Cortical Spreading Depression During Hypothermia and Rewarming in Rat

The present study was carried out to evaluate the effect of hypothermia and rewarming on the pattern of Cortical Spreading Depression(CSD) and predict the resultant vulnerability of the brain. Thirty four Sprague-Dawley rats, either sex, weighing 250-350gm, were used. They were devided into 4 groups, according to the degree of hypothermia and speed of rewarming, Profound Hypothermia & Slow Rewarming(G I), Profound Hypothermia & Rapid Rewarming(G II), Moderate Hypothermia & Slow Rewarming(G III), Moderate Hypothermia & Rapid Rewarming(G IV). CSD was elicited by local application of KC1 and identified by Direct Current Potential(DCP). We estimated the Frequency of DCP, Recovery time of negative shift of DCP, Area of negative shift of DCP according to the change of body temperature. The frequencies of DCP increased after rewarming compared with the normothermic state in all groups, statistical significance(P<0.05) was specially evident in Group II(Profound Hypothermia & Rapid Rewarming group), 5.1+/-0.3/30min.(mean+/-standard error) in normothermic state, while 9.3+/-0.8/30min in rewarming state. Recovery time(width) of DCP was delayed with hypothermia but decreased with rewarming but delayed state compared with normothermic state in all groups, i.e. 34.7+/-1.0sec at normothermic state, 59.9+/-4.3sec at 27.5 degrees C, 40+/-1.4sec at rewarming state in Group II. We can predict that the vulnerability of the brain tissue may be increased during the rewarming state following hypothermia in all groups. Such evidence is more significant in Group II(Profound Hypothermia & Rapid Rewarming) during the period of certain time(30-60min) after rewarming.

Reduction of Postischemic Cerebral Infarction and Cerebral Edema by Superoxide Dismutase and Allopurinol

The authors have inverstigated the hypothesis that ischemic injury could be attenuated by xanthine oxidase inhibitor(Allopurinol) and superoxide dismutase(SOD). This study used rat MAC model. Each animal was assigned to four groups which was composed with control group, allopurinol pretreated group(50mg/kg. I.P single). SOD pretreated group(16,000 I.U/kg I.V q 15min for 4hours) and combined pretreatment group. Oxygen derived free radicals have been implicated in various pathological conditions including ischemia. Xanthine oxidase serve as a source of oxidizing agents such as superoxide radical and hydrogen peroxide. The superoxide flux in normal cells appears to have necessitated the development of SOD, which scavenges the superoxide by dismutation. Infarcted area was measured by computerized morphometric analysis after triphenyl tetrazolium chloride staining, infarcted area was reduced in SOD treated group(p=0.005) and SOD, allopurinol combined group(P=0.035). Brain edema was measured by gravimetric method. And it was reduced in Allopurinol treated group(P=0.001) and SOD allopurinol combined group (P<0.001). Thus it was revealed that ischemic injury might be reduced by either decrease of production or increase of scavenger and the combination of two should be more efficious.

A Clinical Analysis of Surgically Treated 286 Intracranial Aneurysms

We have studied 286 cases of intracranial aneurysm patients, who were admitted, surgically treated and registered at Korea University Medical Center between January, 1980 and February, 1989. This report resents an analysis of 286 cases of surgically treated intracranial aneurysms. The following results were obtained; 1) Intracranial aneurysm was the most common in the 6th decade(100 cases, 35.0%) and the next order was in the 5th decade(82 cases, 28.7%). 2) The male to female ratio was 1 : 1.53, but male predominant below 4th decade. 3) Aneurysmal size was the most common between 3mm and 10mm(264 cases, 85.2%). 4) The most frequent site was anterior communicating artery(102 cases, 32.9%) and the next order was posterior communicating artery(90 cases, 29.0%). 5) The incidence of multiple aneurysm was 6.6%(19 cases). 6) The incidence of single unruptured aneurysm was 7.6%(19 cases), its most common initial symptom was 3rd cranial nerve palsy. 7) The initial clinical status of patients seems to parallel the postoperative prognosis. 8) The degree of cerebral vasospasm on angiography seems to parallel the postoperative prognosis. 9) Postoperative mortality was 10.8%, but it was 3.8% in operation cases after January, 1986. 10) The most common cause of postoperative mortality was cerebral vasospasm(38.7%), and the next order was rebleeding(19.4%).

Neurilemmoma in Olfactory Groove: Case Report

We report a rare case of neurilemmoma developed in olfactory groove. This 32-years old male had a history of progressing headache for 4 months. CT scan revealed well demarcated enhancing mass. Angiography revealed mass effect without tumor staining. At operation, the tumor was attached firmly at cribiform plate, well encapsulated and whitish yellow. Pathologic examination revealed a neurilemmoma.

A Case of Unusual Acoustic Neurinoma: Case Report

A case of cystic acoustic Neurinoma is reported. The Patient was 41 year old man with temporal lobe epilepsy. Computerized tomography disclosed a low density cystic mass at left cerebellopontine angle that extended to suprasellar cistern through tentorium. At operation, multiloculated cysts were found that looked like cysticercosis. Pathological examination revealed a typical neurilemmoma with Antoni A and B area that formed cyst wall.

Glroependymal Cyst;A Case Reoprt

An unusual case of glroependymal cyst involving the lateral ventricle, 3rd ventricle, cerebellopontine angle cistern and prepontine cistern, simultaneously, is reported. The glroependymal cyst is benign developmental cyst that mainly occurs in the cerebrospinal axis in relation to ventricle, but occasionally occurs in relation to extraventricular system, such as subarachnoid space, brain stem and cerebral parenchyme. The histological characteristics of ependymal cyst wall are ependyma-like epithelium and neuroglial tissue.

Experimential Brain Stem Compression

Patterns of brain-stem compression and secondary brain-stem evoked postentials were investigated to correlate with expanding mass volume and location in mass-induced supratentorial brain compression in cats in which the subjects were divided into four experimental group i.e., frontal, temporal, parietal, and occipital brain-compressed groups. Postmortem insepection of the brain-stem showed either unilateral or bilateral dorsal herniation of the brain in frontal and temporal brain-compressed groups and dorsolateral herniation in parietal and occipital brain-compressed groups, respectively. Microscopic examination revealed that the secondary brain-stem hemorrhages were mostly caused by venous bleeding secondary to venous congestion, the bleeding being more severe in occipital brain-compressed group. As the intracranial pressure was raised by expansion of a supratentorial balloon, the late components of the BSEP were suppressed first, followed by the suppression of the early components. In BSEP recording a significant change was observed in Vth wave with prolongation of latency and decrease in amplitude. This finding suggests that the midbrain is the most vulnerable to compression ischemia. In parietal group, the Vth wave started to be prolonged at 0.4ml of balloon expansion and totally disappeared at 1.8ml of expansion.

A Study of the Effect of Naloxone on the Lipid Peroxidation and the Fine Structure of the Myelin Sheath in the Injured Spinal Cord

Spinal Cord contusions in cats were produced experimentally by impact injuries to the surgically exposed cord at the second lumbar vertebral level. As a step in the investigation of the possible effect of spinal cord trauma on biochemical and ultrastructural changes in the injured cord, activities of lipid peroxidation were measured in the frozen-dried sample of the spinal cord and the fine structure of the myelinated nerve fiber in the white matter were observed before and after the cord injury. An increase of lipid peroxidation level was found as early as 30 minutes after the injury and the highest concentration was reached at 4 hours of injury. Fine structures of the myelinated nerve fibers were changed progressively with the lapse of time after the injury. By 1 hour after the contusion the myelinated nerve fibers showed moderately enlarged periaxonal space, attenuation and disarray of the myelin sheaths. By 4 hour after the contusion, there appeared disarray of the myelin sheaths, greatly enlarged periaxonal space and irregulary contoured axons. The effect of naloxone of the lipid peroxidation and fine ultrastructure of the myelinated nerve fibers were studied, and the results of this study suggested that naloxone have a beneficial effect on the change in lipid peroxidation and the preservation of the myelinated nerve fibers after injury.