Jae Hoon Sung

Analysis of anatomical variations of bone and vascular structures around the posterior atlantal arch using three- dimensional computed tomography angiography

OBJECT The current study evaluates the incidence of anatomical variations of the V(3) segment of the vertebral artery (VA) and the posterior arch of the atlas (C-1). Failure to appreciate these types of anatomical variations can cause catastrophic injury to the VA during posterior approaches to the upper cervical spine. METHODS In the present study, the authors analyzed the records of 1013 Korean patients who underwent computed tomography (CT) angiography to evaluate the incidence of anomalous variations in the third segment of the VA and to determine the incidence and morphometric characteristics of any detected posterior ponticuli. The authors also hoped to determine any specific imaging features that might indicate a VA anomaly around the craniovertebral junction. RESULTS The mean age of the patients was approximately 55.7 years and the prevalence of a posterior ponticulus was 15.6%. The incidence rate of a posterior ponticulus in the male population was 19.3%, whereas in the female population it was 12.8%. The incomplete type of posterior ponticulus was more common than the complete type. The mean age of the patients with an incomplete posterior ponticulus (55.7 years) was significantly younger (p = 0.018) than the mean age of patients with a complete posterior ponticulus (57.6 years). The incidence rate of a persistent first inter-segmental artery was 4.7% and the incidence rate of a fenestrated VA was 0.6%. The area of the C-1 transverse foramen on the abnormal side was significantly smaller than that of the contralateral normal side. CONCLUSIONS The shape of the C-1 posterior arch and the third segment of the VA are heterogeneous. Therefore, preoperative radiological studies should be performed to identify any anatomical variations. Using preoperative 3D CT angiography, we can precisely identify an anomalous VA and significantly reduce the risk of VA injury.

Significance of laminar screw fixation in the subaxial cervical spine.

Study Design. We retrospectively reviewed 11 patients who underwent laminar screw fixation in the subaxial cervical spine. In 4 patients, laminar screws were inserted for posterior cervical arthrodesis, and in 7 patients it was used for fixation of the open laminae during laminoplasty. Objective. In this study, the author describes the technique and surgical results of translaminar screw placement in the subaxial cervical spine. Summary of Background Data. The use of laminar screws for fixation of the second cervical vertebra and upper thoracic vertebrae has been introduced as an important technique in spinal surgery because they can avoid injury to adjacent neurovascular structures. However, there have been no reports of translaminar screw use in the subaxial spine including C7. In this study, we describe the use of translaminar screws for fixation of the subaxial cervical spine in cases of degenerative or traumatic spine disease. Methods. Between June 2006 and March 2007, 34 translaminar screws were placed in 11 patients to treat trauma or degenerative disease: 6 at C7, 6 at C6, 7 at C5, 7 at C4, 7 at C3, and 1 at T1. There were 6 women and 5 men. The ages ranged from 23 to 87 years with a mean age of 61.3 years. All patients were evaluated at 6 weeks, as well as at 3 and 6 months using flexion and extension lateral radiographs. Patients requiring fusion were also evaluated with computed tomography at 3 and 6 months to verify arthrodesis. Results. The mean follow-up period was 5.7 months, at which time there was no significant complications from laminar screw placement, except for 2 asymptomatic breaches of the dorsal lamina cortex. Sound bone fusion was identified in cases where arthrodesis was the goal. No screw pullout or avulsion was identified in the laminoplasty cases. Conclusion. The translaminar screw method avoided damaging vascular structures, especially when the vertebral artery courses in the C7 transverse foramen, and it maintains solid stabilization of the subaxial cervical spine. This technique has 2 important advantages to currently used techniques: it is simpler and is not limited by the position of vascular structures. Therefore, it may be applicable to a wider number of patients, especially as it may be used in the subaxial cervical spine.

Motor cortex stimulation for central pain following a traumatic brain injury

Abstract Central pain can occur in any lesions along the central nervous system affecting the spinothalamocortical pathway. Although diverse etiologies have been reported to cause central pain, there are few reports on the occurrence and surgical treatment of central pain following a traumatic brain injury (TBI). This paper describes the occurrence of central pain following a severe TBI, in which the diagnosis of central pain was typically delayed due to the patient’s decreased ability to express his pain for severe aphasia as a neurological sequela. The severe burning pain, deep pressure‐like pain, and deep mechanical allodynia, which presented over the contralateral side to the TBI, were successfully relieved with motor cortex stimulation (MCS). The analgesic effect of stimulation was found to be long lasting and was still present at the 12‐month follow up. As shown in this patient, the occurrence of central pain syndrome should be considered by physicians caring for TBI patients, and a comprehensive, systematic study will be needed to determine the prevalence of central pain after a TBI.

E-cadherin as a predictive marker of brain metastasis in non-small-cell lung cancer, and its regulation by pioglitazone in a preclinical model

It remains unclear whether patients with non-small-cell lung cancer (NSCLC) develop brain metastasis during or after standard therapy. We attempted to identify biological markers that predict brain metastasis, and investigated how to modulate expression of such markers. A case–control study of patients who were newly diagnosed with NSCLC and who had developed brain metastasis during follow-up was conducted between 2004 and 2009. These patients were compared with a control group of patients who had NSCLC but no evidence of brain metastasis. Immunohistochemical analysis of expression of Ki-67, p53, Bcl-2, Bax, vascular endothelial growth factor, epidermal growth factor receptor, caspase-3, and E-cadherin was conducted. The methylation status of the genes for O6-methylguanine-DNA-methyltransferase, tissue inhibitor of matrix metalloproteinase (TIMP)-2, TIMP-3, and death-associated protein-kinase was also determined, by use of a methylation-specific polymerase chain reaction. A significantly increased risk of developing brain metastasis was associated with the presence of primary tumors with low E-cadherin expression in patients with NSCLC. We also investigated the effects of pioglitazone, a peroxisome proliferator-activated receptor γ-activating drug, in tumor-bearing mouse models. We found that E-cadherin expression was proportional to pioglitazone exposure time. Interestingly, pioglitazone pretreatment before cancer cell inoculation prevented loss of E-cadherin expression and reduced expression of MMP9 and fibronectin, compared with the control group. E-cadherin expression could be a predictor of brain metastasis in patients with NSCLC. Preventive treatment with pioglitazone may be useful for modulating E-cadherin expression.

Clinical and Angiographic Features and Stroke Types in Adult Moyamoya Disease

DSA was used to study patients with Moyamoya disease with acute stroke. Advanced Suzuki angiographic stages, aneurysms, arterial occlusions, and collateral flow including transdural anastomoses were present more often in patients with hemorrhage than in those with only ischemia. These findings are the main contributors to the development of hemorrhagic strokes in patients with Moyamoya disease. BACKGROUND AND PURPOSE: This study was conducted to elucidate the association between clinical and angiographic characteristics and stroke types in adult Moyamoya disease that has been rarely evaluated. MATERIALS AND METHODS: We analyzed the clinical and radiologic data obtained from a retrospective adult Moyamoya disease cohort with acute strokes, which were classified into 7 categories: large-artery infarct, hemodynamic infarct, perforator infarct, deep intracerebral hemorrhage, lobar intracerebral hemorrhage, intraventricular hemorrhage, and SAH. With conventional angiography, which was performed in the hemispheres with acute strokes, the Suzuki angiographic stage, intracranial aneurysm, major artery occlusion, and collateral vessel development were confirmed within 1 month of stroke onset. RESULTS: This study included 79 patients with acute ischemic stroke and 96 patients with acute hemorrhagic stroke. The angiographic stage had a strong tendency to be more advanced in the hemorrhagic than the ischemic patients (P = .061). Intracranial aneurysms were more frequently found in the hemorrhagic than ischemic or control hemispheres (P = .002). Occlusions of the anterior cerebral artery and development of fetal-type posterior cerebral artery were more frequently observed in the hemorrhagic than the ischemic (P = .001 and .01, respectively) or control hemispheres (P = .011 and .013, respectively). MCA occlusion (P = .039) and collateral flow development, including the ethmoidal Moyamoya vessels (P = .036) and transdural anastomosis of the external carotid artery (P = .022), occurred more often in the hemorrhagic than the ischemic hemispheres. Anterior cerebral artery occlusion occurred more frequently in patients with deep intracerebral hemorrhage or intraventricular hemorrhage than with lobar intracerebral hemorrhage (P = .009). CONCLUSIONS: In adult Moyamoya disease, major artery occlusion and collateral compensation occurred more often in the hemorrhagic than in the ischemic hemispheres. Thus, anterior cerebral artery occlusion with or without MCA occlusion and intracranial aneurysms may be the main contributing factors to hemorrhagic stroke in adult patients with Moyamoya disease.

Anatomy of Neurovascular Structures Around the Carpal Tunnel During Dynamic Wrist Motion for Endoscopic Carpal Tunnel Release

OBJECTIVE: The purpose of this study is to investigate the anatomic relationship between neurovascular structures and the transverse carpal ligament (TCL) so as to avoid complications during an endoscopic carpal tunnel release procedure. METHODS: Fresh cadaver hands from seven men and 12 women (age range, 48–74 yr) were used. The neurovascular structures just over and under the TCL were meticulously dissected under loupe magnification. Several anatomic landmarks were calculated (average length of the TCL; average distance between the TCL distal margin and the neurovascular structures; and average lengths of the superficial palmar arch, ramus communicantes, recurrent motor branch, and palmar cutaneous branch of the median nerve). The ulnar neurovascular structure was studied with the wrist positioned in neutral, ulnar flexion, and radial flexion. RESULTS: The anatomic relationships between the TCL and vascular and neural structures were measured. The ulnar neurovascular structures usually passed just over ulnar to the superior portion of the hook of the hamate. However, in 11 hands, a looped ulnar artery coursed 1 to 4 mm radial to the hook of the hamate and continued to the superficial palmar arch. The looped ulnar artery migrates on the ulnar side of Guyons canal (-2–2 mm radial to the hook of the hamate) with the wrist in radial flexion (of the wrist). During ulnar flexion of the wrist, the ulnar artery shifts more radially beyond the hook of the hamate (2–7 mm). CONCLUSION: It is appropriate to transect the ligament over 4 mm apart from the lateral margin of the hook of the hamate without placing the edge of the scalpel toward the ulnar side. We would also recommend not transecting the TCL in the ulnar flexed wrist position to protect the ulnar neurovascular structure. The proximal portal could be made just ulnar to the palmaris longus tendon to spare the neurovascular structures in the proximal portion of the TCL.

The Efficacy of Endovascular Treatment of Ruptured Blood Blister-Like Aneurysms Using Stent-Assisted Coil Embolization

We report our experience with endovascular treatment and follow-up results of a ruptured blood blister-like aneurysm (BBA) in the supraclinoid internal carotid artery. We performed a retrospective review of ruptured blood blister-like aneurysm patients over a 30-month period. Seven patients (men/women, 2/5; mean age, 45.6 years) with ruptured BBAs were included from two different institutions. The angiographic findings, treatment strategies, and the clinical (modified Rankin Scale) and angiographic outcomes were retrospectively analyzed. All seven BBAs were located in the supraclinoid internal carotid artery. Four of them were ≥ 3 mm in largest diameter. Primary stent-assisted coiling was performed in six out of seven patients, and double stenting was done in one patient. In four patients, the coiling was augmented by overlapping stent insertion. Two patients experienced early re-hemorrhage, including one major fatal SAH. Complementary treatment was required in two patients, including coil embolization and covered-stent placement, respectively. Six of the seven BBAs showed complete or progressive occlusion at the time of late angiographic follow-up. The clinical midterm outcome was good (mRS scores, 0–1) in five patients. Stent-assisted coiling of a ruptured BBA is technically challenging but can be done with good midterm results. However, as early regrowth/re-rupture remains a problem, repeated, short-term angiographic follow-up is required so that additional treatment can be performed as needed.

Intraoperative Monitoring of Motor-Evoked Potentials for Supratentorial Tumor Surgery

Objective The purpose of this study was to assess the feasibility and clinical efficacy of motor evoked potential (MEP) monitoring for supratentorial tumor surgery. Methods Between 2010 and 2012, to prevent postoperative motor deterioration, MEP recording after transcranial stimulation was performed in 84 patients with supratentorial brain tumors (45 males, 39 females; age range, 24-80 years; median age, 58 years). MEP monitoring results were correlated with postoperative motor outcome compared to preoperative motor status. Results MEP recordings were stable in amplitude (<50% reduction in amplitude) during surgery in 77 patients (91.7%). No postoperative motor deficit was found in 66 out of 77 patients with stable MEP amplitudes. However, postoperative paresis developed in 11 patients. False negative findings were associated with edema in peri-resectional regions and postoperative bleeding in the tumor bed. MEP decrease in amplitude (>50%) occurred in seven patients (8.3%). However, no deficit occurred postoperatively in four patients following preventive management during the operation. Three patients had permanent paresis, which could have been associated with vascular injury during tumor resection. Conclusions MEP monitoring during supratentorial tumor surgery is feasible and safe. However, false negative MEP results associated with postoperative events may occur in some patients. To achieve successful monitoring, collaboration between surgeon, anesthesiologist and an experienced technician is mandatory.

Analysis of accuracy of kyphotic angle measurement for vertebral osteoporotic compression fractures

A reliable and reproducible measurement technique for the sagittal contour in vertebral fractures is paramount to clinical decision-making. This study was designed to determine the most reliable measurement technique in osteoporotic vertebral compression fracture. Fifteen lateral radiographs of thoracic and lumbar fractures were selected and measured on two separate occasions by three spine surgeons using six different measurement techniques (centroid, Harrison posterior tangent method and 4 different types of modified Cobb method). The radiograph quality was assessed and the center beam location was determined. The inter- and intraobserver variance of the Cobb method 4 and the Harrison posterior tangent method were significantly lower than for the other four methods. The intraobserver correlation coefficients were the most consistent using the Cobb method 4 (0.982), followed by the Harrison posterior tangent method (0.953) and Cobb method 1 (0.874). The intraobserver agreement (% of repeated measures within 5 degrees of the original measurement) ranged from 42% to 98% for each technique for all three observers, with the Cobb method 4 showing the best agreement (97.8%) followed by the Harrison posterior tangent method (93.7%). The Cobb method 4 and Harrison posterior tangent method, when applied to measuring the kyphosis, were reliable and had a similar small error range. The Cobb method 4 showed the best overall reliability. The centroid method and the other Cobb methods using a fractured endplate did not produce an accurate result due to inter- and intraobserver differences in determining the baseline.

Significance of Intracranial Pressure Monitoring after Early Decompressive Craniectomy in Patients with Severe Traumatic Brain Injury

Objective Early decompressive craniectomy (DC) has been used as the first stage treatment to prevent secondary injuries in cases of severe traumatic brain injury (TBI). Postoperative management is the major factor that influences outcome. The aim of this study is to investigate the effect of postoperative management, using intracranial pressure (ICP) monitoring and including consecutive DC on the other side, on the two-week mortality in severe TBI patients treated with early DC. Methods Seventy-eight patients with severe TBI [Glasgow Coma Scale (GCS) score <9] underwent early DC were retrospectively investigated. Among 78 patients with early DC, 53 patients were managed by conventional medical treatments and the other, 25 patients were treated under the guidance of ICP monitoring, placed during early DC. In the ICP monitoring group, consecutive DC on the other side were performed on 11 patients due to a high ICP of greater than 30 mm Hg and failure to respond to any other medical treatments. Results The two-week mortality rate was significantly different between two groups [50.9% (27 patients) and 24% (6 patients), respectively, p=0.025]. After adjusting for confounding factors, including sex, low GCS score, and pupillary abnormalities, ICP monitoring was associated with a 78% lower likelihood of 2-week mortality (p=0.021). Conclusion ICP monitoring in conjunction with postoperative treatment, after early DC, is associated with a significantly reduced risk of death.