Hee-Jin Yang

Analysis of the factors influencing bone graft infection after cranioplasty.

BACKGROUND Delayed cranioplasty after decompressive craniectomy was performed using various reconstruction materials and methods. Bone graft infection is a major concern with cranioplasty. This study identified factors that are related to bone graft infection after cranioplasty. METHODS A total of 140 patients underwent reconstructive cranioplasty after decompressive craniectomy between 2000 and 2009. The sample population included 102 male patients and 39 female patients aged 6 years to 76 years, with a mean age of 47.5 years. Autografts were used for cranioplasty when available. Polymethylmethacrylate or customized linear high-density polyethylene was considered when autografts were unavailable. Bone graft infection was defined as the removal of the infected bone graft, and the related factors were evaluated retrospectively. RESULTS Bone graft infection occurred in 11 patients (7.86%). Bone graft infection after cranioplasty was significantly related to the number of operations (p = 0.002), operation time (p = 0.031), and diabetes (p = 0.004). An increased number of operations increased the infection rate from 4.3% to 33%. Infection rates increased rapidly after three times. The infection rate was less than 10% when cranioplasty was completed within 199 minutes. An infection rate greater than 20% was observed when cranioplasty required more than 200 minutes. Other factors, such as graft material, fixation devices, age, sex, the cause of the operation, the interval between craniectomy and cranioplasty, and underlying nondiabetic diseases, did not significantly alter the infection rate. CONCLUSION Short surgical times (<200 minutes) and a lower number of previous operations (less than three times) may decrease the risk of bone flap infection. Careful attention is required when performing cranioplasty, particularly in patients with diabetes. LEVEL OF EVIDENCE Prognostic/therapeutic study, level IV.

Analysis of Complications Following Decompressive Craniectomy for Traumatic Brain Injury

OBJECTIVE Adequate management of increased intracranial pressure (ICP) is critical in patients with traumatic brain injury (TBI), and decompressive craniectomy is widely used to treat refractory increased ICP. The authors reviewed and analyzed complications following decompressive craniectomy for the management of TBI. METHODS A total of 89 consecutive patients who underwent decompressive craniectomy for TBI between February 2004 and February 2009 were reviewed retrospectively. Incidence rates of complications secondary to decompressive craniectomy were determined, and analyses were performed to identify clinical factors associated with the development of complications and the poor outcome. RESULTS Complications secondary to decompressive craniectomy occurred in 48 of the 89 (53.9%) patients. Furthermore, these complications occurred in a sequential fashion at specific times after surgical intervention; cerebral contusion expansion (2.2 ± 1.2 days), newly appearing subdural or epidural hematoma contralateral to the craniectomy defect (1.5 ± 0.9 days), epilepsy (2.7 ± 1.5 days), cerebrospinal fluid leakage through the scalp incision (7.0 ± 4.2 days), and external cerebral herniation (5.5 ± 3.3 days). Subdural effusion (10.8 ± 5.2 days) and postoperative infection (9.8 ± 3.1 days) developed between one and four weeks postoperatively. Trephined and post-traumatic hydrocephalus syndromes developed after one month postoperatively (at 79.5 ± 23.6 and 49.2 ± 14.1 days, respectively). CONCLUSION A poor GCS score (≤ 8) and an age of ≥ 65 were found to be related to the occurrence of one of the above-mentioned complications. These results should help neurosurgeons anticipate these complications, to adopt management strategies that reduce the risks of complications, and to improve clinical outcomes.

Surgical outcome of percutaneous endoscopic interlaminar lumbar diskectomy for recurrent disk herniation after open diskectomy.

Study Design: Technical report. Objective: To present a detailed surgical technique of percutaneous endoscopic interlaminar diskectomy (PEID) for recurrent lumbar disk herniation and present features of postoperative magnetic resonance images that were unavailable in previous studies. Summary of Background Data: Revision lumbar diskectomy is troublesome because of the difficulty in dissecting a surgical scar. Endoscopic diskectomy is regarded as an alternative method with comparable clinical outcome and less complication. Technically, a transforaminal approach is similar to a virgin operation, whereas an interlaminar approach is not, because of the scar tissue. There have been only 2 papers describing a PEID surgical procedure. Sharing details of the surgical technique is important in furthering the adoption of this technique, when it is indicated. Methods: We operated on 10 patients (M:F=6:4; mean age, 61.2±11.6 y) with PEID for recurrent lumbar disk herniation after open diskectomy. The level operated was L5–S1 in 5 cases, L4–5 in 4, and L2–3 in 1. During operation, we dissected the scar tissue from the medial facet joint with a working channel and removed the reherniated disk material after retraction of the scar tissue and the neural tissue together. Dissection of the scar tissue from the neural tissue was not attempted. The follow-up period was 14.4±9.9 months. Results: In all 10 patients, the reherniated disk materials were removed successfully. There was no incidence of dural tear. Postoperative magnetic resonance imaging showed good decompression with thecal sac reexpansion irrespective of the attached scar tissue, except in 1 patient. Excellent or good outcome by Macnab criteria was obtained in 6 of 10 patients, fair outcome in 2, and poor in 2 patients. Rerecurrence occurred in 1 patient 1 year after the surgery. Conclusions: PEID with dissection of the scar tissue from the medial facet joint rather than from the neural tissue may be an effective alternative surgical method for recurrent disk herniation.

An innovative method for detecting surgical errors using indocyanine green angiography during carotid endarterectomy: a preliminary investigation

BackgroundCarotid endarterectomy (CEA) is the most effective treatment method of carotid stenosis or occlusion. Surgeons typically check the blood flow in each vessel using Duplex Doppler ultrasonography or radiocontrast angiography in order to prevent postoperative complications. Embolic cerebral infarction on the ipsilateral side has been reported in 4–7% of patients undergoing CEA despite a tolerable blood flow reported by Duplex ultrasonography. This study was designed to evaluate a new intraoperative method for detecting technical errors during CEA using indocyanine green (ICG) angiography.MethodsSix consecutive patients with severe carotid stenosis or occlusion underwent CEA. Both ICG angiography and Doppler ultrasonography were performed before the carotid arterial incision and after the carotid arterial suture. After injecting ICG dye via an intravenous route, the internal surface, atheroma, and flow defect were visualized with a microscope.ResultsIn ICG angiography, stenotic lesions could be identified as regions of relatively dark signal intensity. Magnified real-time images could be created using a microscope with an infrared filter, including three-dimensional images and detailed images of the inner lumen. These images could then be compared with the results of Doppler ultrasonography. In the six cases assessed by both ICG angiography and Doppler ultrasonography, all Doppler results were acceptable. However, one patient underwent revision surgery because a fluttering atheroma was detected by ICG angiography. ICG angiography could assume the extent of severe stenotic area. ICG angiography could also detect mobile lesions such as a fluttering atheroma.ConclusionsIntraoperative ICG angiography before arteriotomy is useful to determine the precise stenotic area and the shape of the associated plaque. ICG angiography after an arteriotomy site is sutured is also useful for detecting residual stenosis or fluttering atheroma. ICG angiography could be an alternative method to Doppler ultrasonography for ensuring a complete and successful operation and preventing complications.

Medial Loop of V2 Segment of Vertebral Artery Causing Compression of Proximal Cervical Root

Objective It is rare that the medial loop in the V2 segment of the vertebral artery (VA) causes compression of the proximal cervical root of the spinal cord without leading to bony erosion and an enlarged foramen. We evaluated the clinical significance and incidence of the medial loop in the V2 segment of the VA. Methods We reviewed the records from 1000 consecutive patients who had undergone magnetic resonance imaging evaluation of the cervical spine between January 2005 and January 2008. The inclusion criteria were that over a third of the axial aspect of the VA located in the intervertebral foramen was inside the line between the most ventral points of the bilateral lateral mass, and that the ipsilateral proximal root deviated dorsally because of the medial loop of the VA. We excluded cases of bone erosion, a widened foramen at the medial loop of the VA, any bony abnormalities, tumors displacing VA, or vertebral fractures. The medical records were reviewed retrospectively to search for factors of clinical significance. Results In six patients (0.6%), the VA formed a medial loop that caused compression of the proximal cervical root. One of these patients had the cervical radiculopathy that developed after minor trauma but the others did not present with cervical radiculopathy related to the medial loop of the VA. Conclusion The medial loop of the VA might have a direct effect on cervical radiculopathy. Therefore, this feature should be of critical consideration in preoperative planning and during surgery.

Mobile Computed Tomography : Three Year Clinical Experience in Korea

Objective Obtaining real-time image is essential for neurosurgeons to minimize invasion of normal brain tissue and to prompt diagnosis of intracranial event. The aim of this study was to report our three-year experience with a mobile computed tomography (mCT) for intraoperative and bedside scanning. Methods A total of 357 mCT (297 patients) scans from January 2009 to December 2011 in single institution were reviewed. After excluding post-operative routine follow-up, 202 mCT were included for analysis. Their medical records such as diagnosis, clinical application, impact on decision making, times, image quality and radiologic findings were assessed. Results Two-hundred-two mCT scans were performed in the operation room (n=192, 95%) or intensive care unit (ICU) (n=10, 5%). Regarding intraoperative images, extent of resection of tumor (n=55, 27.2%), degree of hematoma removal (n=42, 20.8%), confirmation of catheter placement (n=91, 45.0%) and monitoring unexpected complications (n=4, 2.0%) were evaluated. A total of 14 additional procedures were introduced after confirmation of residual tumor (n=7, 50%), hematoma (n=2, 14.3%), malpositioned catheter (n=3, 21.4%) and newly developed intracranial events (n=2, 14.3%). Every image was obtained within 15 minutes and image quality was sufficient for interpretation. Conclusion mCT is feasible for prompt intraoperative and ICU monitoring with enhanced diagnostic certainty, safety and efficiency.

Post-carotid endarterectomy cerebral hyperperfusion syndrome : is it preventable by strict blood pressure control?

Objective Cerebral hyperperfusion syndrome (CHS) is a serious complication after carotid endarterectomy (CEA). However, the prevalence of CHS has decreased as techniques have improved. This study evaluates the role of strict blood pressure (BP) control for the prevention of CHS. Methods All 18 patients who received CEA from February 2009 through November 2012 were retrospectively reviewed. All patients were routinely managed in an intensive care unit by a same protocol. The cerebral perfusion state was evaluated on the basis of the regional cerebral blood flow (rCBF) study by perfusion computed tomography (pCT) and mean velocity by transcranial doppler (TCD). BP was strictly controlled (<140/90 mm Hg) for 7 days. When either post-CEA hyperperfusion (>100% increase in the rCBF by pCT or in the mean velocity by TCD compared with preoperative values) or CHS was detected, BP was maintained below 120/80 mm Hg. Results TCD and pCT data on the patients were analyzed. Ipsilateral rCBF was significantly increased after CEA in the pCT (p=0.049). Post-CEA hyperperfusion was observed in 3 patients (18.7%) in the pCT and 2 patients (12.5%) in the TCD study. No patients developed clinical CHS for one month after CEA. Furthermore, no patients developed additional neurological deficits related to postoperative cerebrovascular complications. Conclusion Intensive care with strict BP control (<140/90 mm Hg) achieved a low prevalence of post-CEA hyperperfusion and prevented CHS. This study suggests that intensive care with strict BP control can prevent the prevalence of post-CEA CHS.

Quantitative Analysis of Intraoperative Indocyanine Green Video Angiography in Aneurysm Surgery

Objective Indocyanine green (ICG) videoangiography (VA) is being used in assessment of blood flow during cerebrovascular surgery. However, data collected during ICG angiography are usually interpreted qualitatively. In this study, quantitative analysis of ICG angiogram was attempted. Materials and Methods ICG VA, performed during aneurysm surgery was analyzed retrospectively. The angiogram was captured serially in regular time interval. The stacked images were then fed into an image analysis program, ImageJ. The selected areas of interest were as follows: parent and branch vessels, and dome of aneurysm. Changes of signals of measurement points were plotted. The time to peak, washout time, and the peak intensity between areas were compared. Results Among the 16 cases enrolled in this study, five cases were anterior communicating artery aneurysms, and 11 cases were middle cerebral artery bifurcation aneurysms. There was no signal intensity of aneurysm dome in our series. No difference in time to peak or maximum signal intensity was observed between vessels in each case. The average time to peak was 9.0 and washout time was 31.3 seconds. No significant difference in time profile was observed between anterior communicating artery aneurysms and middle cerebral artery bifurcation aneurysms. Conclusion Findings of this study demonstrate that quantitative analysis is possible using a personal computer and common video capture and analysis software. It can be a good adjunctive to evaluation of vascular status during aneurysm surgery. It displays time profiles of multiple points of interest over time, and is helpful in objective evaluation of changes of blood flow over time. It might be helpful in various fields of cerebrovascular surgery.

The Impact of Menopause on Bone Fusion after the Single-Level Anterior Cervical Discectomy and Fusion

Objective To evaluate the successful fusion rate in postmenopausal women with single-level anterior cervical discectomy and successful fusion (ACDF) and identify the significant factors related to bone successful fusion in pre- and postmenopausal women. Methods From July 2004 to December 2010, 108 consecutive patients who underwent single-level ACDF were prospectively selected as candidates. Among these, the charts and radiological data of 39 women were reviewed retrospectively. These 39 women were divided into two groups : a premenopausal group (n=11) and a postmenopausal group (n=28). To evaluate the significant factors affecting the successful fusion rate, the following were analyzed : the presence of successful fusion, successful fusion type, age, operated level, bone mineral density, graft materials, stand-alone cage or plating with autologous iliac bone, subsidence, adjacent segment degeneration, smoking, diabetes mellitus, and renal disease. Results The successful fusion rates of the pre- and postmenopausal groups were 90.9% and 89.2%, respectively. There was no significant difference in the successful fusion rate or successful fusion type between the two groups. In the postmenopausal group, three patients (10.8%) had successful fusion failure. In the postmenopausal group, age and subsidence significantly affected the successful fusion rate (p=0.016 and 0.011, respectively), and the incidence of subsidence in patients with a cage was higher than that in patients with a plate (p=0.030). Conclusion Menopausal status did not significantly affect bone successful fusion in patients with single-level ACDF. However, in older women with single-level ACDF, the combination of use of a cage and subsidence may unfavorably affect successful fusion.

Difference in Spinal Fusion Process in Osteopenic and Nonosteopenic Living Rat Models Using Serial Microcomputed Tomography

Objective To identify and investigate differences in spinal fusion between the normal and osteopenic spine in a rat model. Methods Female Sprague Dawley rats underwent either an ovariectomy (OVX) or sham operation and were randomized into two groups: non-OVX group and OVX group. Eight weeks after OVX, unilateral lumbar spinal fusion was performed using autologous iliac bone. Bone density (BD) was measured 2 days and 8 weeks after fusion surgery. Microcomputed tomography was used to evaluate the process of bone fusion every two weeks for 8 weeks after fusion surgery. The fusion rate, fusion process, and bone volume parameters of fusion bed were compared between the two groups. Results BD was significantly higher in the non-OVX group than in the OVX group 2 days and 8 weeks after fusion surgery. The fusion rate in the non-OVX group was higher than that in the OVX group 8 weeks after surgery (p=0.044). The bony connection of bone fragments with transverse processes and bone formation between transverse processes in non-OVX group were significantly superior to those of OVX group from 6 weeks after fusion surgery. The compactness and bone maturation of fusion bed in non-OVX were prominent compared with the non-OVX group. Conclusion The fusion rate in OVX group was inferior to non-OVX group at late stage after fusion surgery. Bone maturation of fusion bed in the OVX group was inferior compared with the non-OVX group. Fusion enhancement strategies at early stage may be needed to patients with osteoporosis who need spine fusion surgery.