Young-Je Son

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.

Clinical analysis of vertebrobasilar dissection

SummaryBackground. The natural history of vertebrobasilar artery dissection (VAD) is not fully known. The purpose of this study was to review the clinical outcome of the patients with VAD, then to propose an appropriate management strategy for VAD.Method. From 1992 to 2004, 35 VAD patients admitted to our institutes were retrospectively reviewed. There were 28 men and 7 women, whose age ranged from 4 to 67 years with a mean age of 44 years. Angiography was assessed to document the shape, and location of the dissecting aneurysm with respect to the posterior inferior cerebellar artery (PICA). A modified Rankin score was assigned for functional outcome. The functional outcome scores were analyzed according to the patient’s age, gender, hypertension history, the pattern of initial manifestation, angiographic shape of VAD, angiographic location of VAD, treatment modality.Findings. There was no statistically significant difference between the functional outcome with age, gender, trauma history and past medical history of hypertension. Of 35 patients, 22 presented with SAH, 11 with ischemic symptoms and 2 were incidentally detected. The patients without SAH had a better functional outcome than those with SAH (p = 0.029). There was statistical significance between Hunt–Hess (H–H) grade and clinical outcome (p = 0.032). The shape and location of VAD was not significantly related to the functional outcome (p = 0.294, 0.840). But all the cases of rebleeding and mortality (except one case with initially poor H–H grade) developed exclusively in patients with aneurysms. There was no statistically significant correlation between the treatment modality and the outcome (p = 0.691).Conclusion. The VAD patients with SAH would be recommended to be managed by either surgical or endovascular treatment, but those without SAH, could be managed conservatively with antiplatelet therapy and/or anticoagulation.

Intra-arterial nimodipine infusion for cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage.

This study evaluated the efficacy of intra-arterial nimodipine infusion for symptomatic vasospasm in patients with aneurysmal subarachnoid hemorrhage (aSAH). Clinical data collected from 42 consecutive patients with symptomatic vasospasm after aSAH were retrospectively reviewed. Forty-two patients underwent 101 sessions of intra-arterial nimodipine infusion. Angiographic response, immediate clinical response, and clinical outcome were evaluated at discharge and six months later. Angiographic improvement was achieved in 82.2% of patients. The immediate clinical improvement rate was 68.3%, while the deterioration rate was 5.0%. A favorable clinical outcome was achieved in 76.2% at discharge and 84.6% six months. Vasospasm-related infarction occurred in 21.4%. There was no drug-related complication. The nimodipine group showed satisfactory outcomes. Nimodipine can be recommended as an effective and safe intra-arterial agent for the treatment of symptomatic vasospasm after aSAH.

A retrospective analysis on the natural history of incidental small paraclinoid unruptured aneurysm

Objective The optimal consensus concerning treatment of incidental small paraclinoid unruptured intracranial aneurysms (UIAs) remains controversial. The aim of this retrospective study was to reveal the natural history of small paraclinoid UIAs with the goal of informing the treatment plan. Methods 524 patients harbouring 568 paraclinoid UIAs (≤5 mm) were retrospectively evaluated during the mean follow-up of 35.4 months. The aneurysms were divided into two groups with respect to arterial branch: related (ophthalmic and superior hypophyseal artery), and non-related. Medical records were reviewed concerning multiple variables, such as sex, age, hypertension (HTN), diabetes mellitus, smoking and aneurysmal factors (size, arterial relationship, multiplicity and the occurrence of rupture and growth). The cumulative risk and the risk factors of aneurysmal rupture and growth were analysed. Results Two aneurysmal (0.35%) ruptures and 17 growths (3.0%) were observed during the follow-up of 1675.5 aneurysm-years with an annual rupture of 0.12% and an annual growth of 1.01%. The cumulative survival without aneurysmal growth reached a significant difference in aneurysms ≥4 mm (p=0.001), HTN (p=0.002), and arterial branch-related location (p=0.001). Multivariate analysis disclosed that aneurysm ≥4 mm (HR, 4.41; p=0.003), HTN (HR, 5.74; p=0.003), arterial branch-related location (HR, 6.04; p=0.002), and multiplicity (HR, 0.27; p=0.042) were significant predictive factors for aneurysm growth. Conclusions Although incidental small paraclinoid UIAs have a relatively lower rupture and growth risk, patients with high-risk factors, including aneurysm ≥4 mm, HTN, arterial branch-related aneurysms, and multiple aneurysms must be monitored closely. The limitation of the retrospective nature of this study should be taken into consideration.

The effect of brain atrophy on outcome after a large cerebral infarction

Purpose We retrospectively evaluated the effect of brain atrophy on the outcome of patients after a large cerebral infarct. Methods Between June 2003 and Oct 2008, 134 of 2975 patients with stroke were diagnosed as having a large cerebral infarct. The mean age of the patients was 70 (21–95) y. The mean infarct volume was 223.6±95.2 cm3 (46.0–491.0). The inter-caudate distance (ICD) was calculated as an indicator of brain atrophy by measuring the hemi-ICD of the intact side and then multiplying by two to account for brain swelling at the infarct site. The mean ICD was 18.0±4.8 mm (9.6–37.6). Results Forty-nine (36.6%) patients experienced a malignant clinical outcome (MCO) during management in the hospital. Thirty-one (23.1%) patients had a favourable functional outcome (FO) (modified Rankin scale (mRS) ≤3) and 49 (36.6%) had an acceptable functional outcome (AO) (mRS≤4) at 6 months after stroke onset. In the multivariate analysis, brain atrophy (ICD≥20 mm) had a significant and independent protective effect on MCO (p=0.003; OR=0.137; 95% CI 0.037 to 0.503). With respect to FO, the age and infarct volume reached statistical significance (p<0.001, OR=0.844, 95% CI 0.781 to 0.913; p=0.006, OR=0.987, 95% CI 0.977 to 0.996, respectively). Brain atrophy (ICD≥20 mm) was negatively associated only with AO (p=0.022; OR=0.164; 95% CI 0.035 to 0.767). Conclusions Brain atrophy may have an association with clinical outcome after a large stroke by a trend of saving patients from an MCO but also by interfering with their functional recovery.

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.

Intracranial Pial Arteriovenous Fistulas

Intracranial pial arteriovenous fistula (AVF) is a rare cerebrovascular lesion that has only recently been recognized as a distinct pathological entity. A 41-year-old woman (Patient 1) presented with the sudden development of an altered mental state. Brain CT showed an acute subdural hematoma. A red sylvian vein was found intraoperatively. A pial AVF was revealed on postoperative angiography, and surgical disconnection of the AVF was performed. A 10-year-old boy (Patient 2) presented with a 10-day history of paraparesis and urinary incontinence. Brain, spinal MRI and angiography revealed an intracranial pial AVF and a spinal perimedullary AVF. Endovascular embolization was performed for both lesions. The AVFs were completely obliterated in both patients. On follow-up, patient 1 reported having no difficulty in performing activities of daily living. Patient 2 is currently able to walk without assistance and voids into a diaper. Intracranial pial AVF is a rare disease entity that can be treated with surgical disconnection or endovascular embolization. It is important for the appropriate treatment strategy to be selected on the basis of patientspecific and lesion-specific factors in order to achieve good outcomes.

Image-Guided Surgery for Treatment of Unruptured Middle Cerebral Artery Aneurysms

OBJECTIVE Direct surgical clipping appears to be an efficient means for managing unruptured middle cerebral artery (MCA) aneurysms, owing to several angioanatomic features. Here, we present a minimally invasive technique that uses navigation guidance for the treatment of unruptured MCA aneurysms. METHODS Between July of 2003 and June of 2005, we used image-guidance navigation to operate on 24 patients who were diagnosed with unruptured MCA aneurysm. Five men and 19 women were included in the study, and their ages ranged from 43 to 70 years (mean, 58 yr). We predetermined the transsylvian trajectory toward the aneurysm and planned a tailored craniotomy for each patient. RESULTS All aneurysms were readily identified and successfully clipped via craniotomies of less than 3 cm in diameter. We experienced no surgical complications, and each patient had an uneventful postoperative course. CONCLUSION With the aid of navigation, we were able to easily locate MCA aneurysms and perform minimally invasive surgeries such as mini-craniotomies, tailored sylvian dissections, and successful clippings of unruptured MCA aneurysms. In addition, we obtained satisfactory cosmetic results.

Comparison of localizing values of various diagnostic tests in non-lesional medial temporal lobe epilepsy

Though the surgical treatment for medial temporal lobe epilepsy yields a high success rate, more studies are needed in order to determine the most efficacious pre-operative algorithm. The authors studied the relationship between surgical outcome and the localization results of various pre-operative diagnostic tests to assess the predictive value. Seventy-one consecutive patients who had undergone anterior temporal lobectomy with amygdalohippocampectomy with the diagnosis of non-lesional medial temporal lobe epilepsy, who had been followed up more than 24 months, were analyzed retrospectively. Electroencephalogy (EEG), magnetic resonance imaging (MRI), proton emission tomography (PET), single photon emission computed tomography (SPECT), the Wada test, and neuropsychological testing were analyzed. There was no diagnostic test that was found to have a statistically significant relationship between Engel Class I outcome and localization results (P & 0.05). SPECT, neuropsychological testing, and the Wada test all had less predictive values (P < 0.01). EEG and PET had comparable predictive values for Engel Class I with MRI (P & 0.05). No single diagnostic test alone is sufficient to make a diagnosis of non-lesional medial temporal lobe epilepsy. MRI, EEG and PET had comparable predictive values for Engel Class I. SPECT, neuropsychological testing, and the Wada test had less predictive values.