Incidence and risk factors of chronic subdural hematoma after aneurysmal clipping

Efficacy of endovascular treatment for distal anterior cerebral artery aneurysms: A multicenter observational study

OBJECTIVES

Distal anterior cerebral artery (DACA) aneurysms account for 1%-9% of all intracranial aneurysms. Microsurgical treatment is generally preferred for DACA aneurysms; however, it presents challenges owing to the anatomical complexities. Advances in neuro-interventional techniques have yielded promising results. This study aims to compare the clinical outcomes of DACA aneurysms treated with microsurgery and endovascular treatment (EVT) to elucidate the efficacy of EVT.

MATERIALS AND METHODS

A multicenter observational registry comprising 16 stroke centers was utilized for this study. Data was retrospectively and prospectively analyzed from 166 patients with DACA aneurysms in our database, which included 4,552 consecutive patients with ruptured or unruptured intracranial aneurysms who underwent microsurgical or endovascular treatment between January 2013 and December 2021.

RESULTS

Surgical clipping was performed in 115 patients, and 51 underwent coil embolization. The median follow-up duration was 15.3 months. No significant differences were observed in patient characteristics between the two treatment modalities. There were no differences in complication-related morbidity between the microsurgical treatment and EVT groups in either unruptured (10.5% vs. 9.1%, p=1.00) or ruptured aneurysms (5.2% vs. 6.9%, p=0.66). Coil embolization resulted in higher recurrence and retreatment rates than surgical clipping did, especially for ruptured aneurysms (2.6% vs. 27.6%, p<0.01).

CONCLUSIONS

Endovascular treatment is an alternative to microsurgery for DACA aneurysms especially in unruptured cases or the patients who have difficulty undergoing craniotomy due to their general condition, albeit with considerations for higher recurrence and retreatment rates, particularly in ruptured cases. Close follow-up is crucial for the effective management of these challenges. Further studies are needed to refine the treatment strategies for DACA aneurysms.

Natural course of chronic subdural hematoma following surgical clipping of unruptured intracranial aneurysm by pterional approach

OBJECTIVE

Chronic subdural hematoma (CSDH) is a neurological complication following clipping surgery. However, the natural course and ideal approach for the treatment of clipping-related-CSDH (CR-CSDH) have not been clearly established. We aimed to investigate the course of CR-CSDH using chronological radiological findings.

METHODS

We performed a retrospective analysis of 28 (3.8%) patients who developed CSDH among 736 patients who underwent surgical clipping using pterional approach for unruptured aneurysms at our institution between December 2010 and December 2018. Patients underwent follow-up CT scan 6-8 weeks after clipping surgery and decision to pursue surgical intervention rests upon the patient's symptom based on the Markwalder's grading scale (MGS) and numeric rating scale (NRS).

RESULTS

Of the 28 patients, 3 patients (10.7%) underwent surgery, while 25 (89.2%) showed spontaneous resolution of CR-CSDH. Eighteen patients (64.2%) had mild headache with MGS of 0-1. The mean maximum hematoma volume was 41.9±30.9 ml (5.8-135 ml), and 26 patients (92.8%) had homogeneous hematoma. The mean time to hematoma resolution was 126.7±52.9 days (46-228 days). Comparing group of CR-CSDH volume ≥43 ml or a midline shift ≥5 mm, the difference in presence of linear low-density area (p=0.002) and age (p=0.026) between the conservative and operative groups were found to be statistically significant.

CONCLUSIONS

Most CR-CSDH cases spontaneously resolved within 4 months. Therefore, we suggest that close observation should be performed if patient's symptoms are mild and special radiologic findings are present, despite its relatively large volume and midline shifting.

Subdural Hygroma After Management of Ruptured Intracranial Aneurysms: Incidence, Associated Factors, Clinical Course, and Management Options

OBJECTIVE

To evaluate the incidence, associated factors, clinical course, and management options of subdural hygroma in patients treated for aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

From January 2013 until June 2022, 336 consecutive patients with aSAH underwent treatment in our center. No one patient was excluded from the study cohort. Computed tomography (CT) examinations were performed at admission, immediately after surgery and on the first postoperative day, and subsequently in case of any neurologic deterioration or, at least, once per week until discharge from the hospital. Thereafter, CT examinations were at the discretion of specialists in the rehabilitation facility, referring physicians, or neurosurgeons at the outpatient clinic.

RESULTS

The length of radiologic follow-up starting from CT at admission ranged from 1 to 3286 days (mean, 673 ± 895 days; median, 150 days). Subdural hygromas developed in 84 patients (25%). An average interval until this imaging finding from the initial CT examination was 25 ± 55 days (median, 8 days; range, 0-362 days). Evaluation in the multivariate model showed that patient age ≥72 years (P < 0.0001), cerebrospinal fluid (CSF) shunting (P < 0.0001), and microsurgical clipping of ruptured intracranial aneurysm (RIA; P < 0.0001) are independently associated with the development of subdural hygroma. In 54 of 84 cases (64%), subdural hygromas required observation only. Increase of the lesion size with (5 cases) or without (10 cases) appearance of midline shift was associated with patient age <72 years (P = 0.0398), decompressive craniotomy (P = 0.0192), and CSF shunting (P = 0.0009), whereas evaluation of these factors in the multivariate model confirmed independent association of only CSF shunting (P = 0.0003). Active management of subdural hygromas included adjustment of the shunt programmable valve opening pressure, cranioplasty, external subdural drainage, or their combination. Overall, during follow-up (mean, 531 ± 824 days; median, 119 days; range, 2-3285 days) after the start of observation or applied treatment, subdural hygromas showed either decrease (50 cases) or stabilization (34 cases) of their sizes, and no one lesion showed progression again.

CONCLUSIONS

The clinical course of subdural hygromas in patients treated for aSAH is generally favorable, but occasionally these lesions show progressive enlargement with or without the appearance of midline shift, which requires active management.

Subdural hygroma and hemorrhagic conversion after microsurgical clipping for unruptured intracranial aneurysm

BACKGROUND

Chronic subdural hematoma (cSDH) is a unique hemorrhagic complication associated with microsurgical clipping. We aimed to investigate the risk factors of subdural hygroma (SDG) formation and its hemorrhagic conversion to cSDH.

METHODS

We reviewed the medical records of 229 patients who underwent microsurgical clipping for unruptured intracranial aneurysms (UIA) from 2016 to 2019. Risk factors for SDG and cSDH formation were analyzed.

RESULTS

Male sex, age ≥ 60 years, higher degree of arachnoid dissection, severe brain atrophy, and a large volume of subdural fluid collection (SFC) before discharge were independent risk factors for SDG formation. The risk factors for hemorrhagic conversion from SDG were continuous use or early resumption of antiplatelet drugs (odds ratio (OR): 15.367, 95% CI: 1.172-201.402) and a larger volume of SFC before discharge (OR: 0.932, 95% CI: 0.886-0.980). In the early resumption group, antiplatelet drug was resumed at a mean duration of 7.48 days postoperatively, and hemorrhagic conversion was detected earlier than that in the late resumption or no-use groups (4.09 vs. 7.18 weeks, P = 0.046). Following the receiver operating characteristic analysis, the SFC cutoff volume for hemorrhagic conversion was determined to be 23.55 mL.

CONCLUSION

These findings can assist clinicians in identifying patients at a high risk of SDG and cSDH formation. Antiplatelet resumption and its timing should be determined with consideration of the risk of cSDH formation as well as individual medical conditions.

Chronic Subdural Hematoma after Craniotomy with Preoperative Embolization of Middle Meningeal Artery: A Case Report

Endovascular embolization of the middle meningeal artery (MMA) has been reported as an effective method for treating chronic subdural hematoma (CSDH); however, its preventive effect on CSDH following craniotomy is unknown. We present a case in which MMA embolization was ineffective in preventing CSDH following craniotomy. A 56-year-old man who complained of diplopia was diagnosed with sphenoid ridge meningioma with a 3-cm diameter. MMA embolization prior to the operation and total surgical removal of the tumor were performed. Two months postoperatively, the patient complained of headache and hemiparesis of the left side. CSDH with a 15-mm thickness and a midline shift was observed. MMA embolization before inflammation may not play a role in preventing CSDH development because MMA embolization is considered effective in CSDH because it is associated with the blood supply of neovessels that are newly formed due to inflammation. Therefore, MMA embolization might not be effective in preventing the occurrence of CSDH following craniotomy.

Readmission Trends Related to Unruptured Intracranial Aneurysm Treatment

Background and Purpose: Aneurysmal subarachnoid hemorrhage (SAH) is associated with high mortality. Prophylactic treatment of the unruptured intracranial aneurysm (UIA) is considered in a select group of patients thought to be at high for aneurysmal rupture. Hospital readmission rates can serve as a surrogate marker for the safety and cost-effectiveness of treatment options for UIAs; we present an analysis of the 30-day rehospitalization rates and predictors of readmission following UIA treatment with surgical and endovascular approaches. Methods: We retrospectively analyzed data from the National Readmission Database (NRD) derived from the Healthcare Cost and Utilization Project for the year 2014. The cohort included patients with a primary discharge diagnosis of a treated unruptured aneurysm. The primary outcome variable was the 30-day readmission rate in open surgical vs. endovascularly treated groups. The secondary outcomes included predictors of readmissions, and causes of 30-day readmissions in these two groups. Results: The 30-day readmission rate for the surgical group was 8.37% compared to 4.87% for the endovascular group. The index hospitalization duration was longer in the surgical group. A larger proportion of the patients readmitted following surgical treatment were hypertensive (76.35, vs. 63.43%), but the prevalence of other medical comorbidities was comparable in the two treatment groups. Conclusions: There is a higher likelihood for 30-day readmission, longer duration of initial hospitalization and a lower likelihood of discharge home following surgical treatment of UIAs when compared to endovascular treatment. These findings, however, do not demonstrate long-term superiority of one specific treatment modality.

Arachnoid Plasty to Prevent and Reduce Chronic Subdural Hematoma after Clipping Surgery for Unruptured Intracranial Aneurysm : A Meta-Analysis

Objective

Recent studies have reported that arachnoid plasty (ARP) using gelatin sponges with fibrin glue reduced the occurrence of chronic subdural hematoma (CSDH) following clipping surgery for unruptured intracranial aneurysm (UIA). This meta-analysis was conducted to collate further evidence for the efficacy of ARP in preventing postoperative CSDH.

Methods

Data of patients who underwent clipping surgery were extracted from PubMed, EMBASE, and Cochrane Central Register of Controlled Trials by two independent reviewers. A random effects model was used to investigate the efficacy of ARP by using odd ratios (ORs) and 95% confidence intervals (CIs). A meta-regression analysis for male sex was additionally preformed.

Results

Data from six studies with 1715 patients were consecutively included. Meta-analysis revealed that ARP was significantly associated with lower rates of CSDH development after surgical clipping for UIA (ARP group vs. control group : 3.2% vs. 7.2%; OR, 0.40; 95% CI, 0.18–0.93; I² =44.3%; p=0.110). Meta-regression analysis did not highlight any modifying effect of the male sex on postoperative CSDH development (p=0.951).

Conclusion

This meta-analysis indicated that ARP reduced the incidence rates of CSDH following clipping surgery for UIA. If feasible, ARP would be implemented as an additional surgical technique to prevent postoperative CSDH development during surgical clipping of UIA.

Extensive postoperative subdural fluid volume affects the onset of chronic subdural hematoma after unruptured aneurysmal clipping surgery

OBJECTIVE

To evaluate risk factors associated with chronic subdural hematoma (CSDH) onset after clipping surgery for unruptured intracranial aneurysm, and determine whether intraoperative conventional arachnoid-plasty (ARP) can suppress the CSDH onset by reducing subdural fluid volume.

PATIENTS AND METHODS

We retrospectively evaluated 217 patients who underwent surgical clipping at our institution from 2012 to 2018. Risk and predictive factors for symptomatic CSDH development including clinical characteristics, postoperative subdural fluid volume, Hounsfield unit (HU) value of subdural fluid density evaluated by CT and the effect of conventional ARP were compared between CSDH and non-CSDH groups.

RESULTS

Of 217 patients who underwent surgical clipping for anterior circulation aneurysm, 209 were included in this study. Among whom, postoperative CSDH, required burr irrigation, occurred in 12 (5.7%). Mean age was significantly higher in the CSDH group (70 ± 8 years) than in the non-CSDH group (64 ± 11 years, p = 0.03). Subdural fluid volumes on postoperative day (POD)1, POD8 and POD30 were significantly larger in the CSDH group than in the non-CSDH group (38.4 ± 33.5 cm³, 54.8 ± 36.3 cm³, 77.2 ± 36.1 cm³ vs 10.0 ± 7.7 cm³, 16.1 ± 12.8 cm³, 14.0 ± 17.5 cm³, p < 0.001, respectively). However, intraoperative conventional ARP did not reduce postoperative subdural fluid volume nor suppress onset of CSDH. Multivariate logistic regression analysis revealed extensive subdural fluid volume as the only risk factor independently associated with CSDH development.

CONCLUSIONS

In this study, postoperative large subdural fluid volume represented an independent risk factor associated with the incidence of CSDH after unruptured aneurysmal clipping. Reducing subdural fluid volume strategy could suppress the onset of CSDH after surgery.

Potential Risks and Limited Indications of the Supraorbital Keyhole Approach for Clipping Internal Carotid Artery Aneurysms

Background

Internal carotid artery (ICA) aneurysm may be a good target for supraorbital keyhole clipping. We discuss the surgical indications and risks of keyhole clipping for ICA aneurysms based on long-term clinical and radiologic results.

Methods

This was a retrospective analysis of 51 patients (aged 35–75 years, mean 62 years) with ICA aneurysms (mean 5.8 ± 1.8 mm) who underwent clipping via the supraorbital keyhole approach between 2005 and 2017. Neurologic and cognitive functions were examined by several methods, including the modified Rankin Scale and Mini-Mental Status Examination. The state of clipping was assessed 1 year and then every few years after the operation.

Results

Complete clipping was confirmed in 45 patients (88.2%), dog-ear remnants behind the clip persisted in 4 patients, and wrapping was performed in 2 patients. Mean duration of postoperative hospitalization was 3.4 ± 6.9 days. The mean clinical follow-up period was 6.6 ± 3.2 years. The overall mortality was 0, and overall morbidity (modified Rankin Scale score ≥2 or Mini-Mental Status Examination <24) was 3.9%. Completely clipped aneurysms did not show any recurrence during the mean follow-up period of 6.3 ± 3.1 years, but the 2 (3.9%) aneurysms with neck remnants showed regrowth.

Conclusions

The risk of neck remnant behind the clip blade is a drawback of supraorbital keyhole clipping. The surgical indication requires preoperative simulation and careful checking of the clip blade state is essential.

Intraoperative Mannitol Administration Increases the Risk of Postoperative Chronic Subdural Hemorrhage After Unruptured Aneurysm Surgery

OBJECTIVE

Although mannitol is used widely to facilitate brain retraction in cases of ruptured aneurysms, there is no consensus about the intraoperative administration of mannitol in the case of unruptured aneurysms. Accordingly, this study was conducted to identify an intraoperative mannitol administration strategy.

METHODS

Mannitol was administered routinely to patients (n = 90) from January 2015 to April 2016 and not administered to patients (n = 97) from May 2016 to June 2017. The patient groups with and without mannitol administration were then compared based on the patient medical records, radiologic data, and digital recordings from an intraoperative microscope.

RESULTS

The patient groups with and without mannitol administration were comparable regarding patient age, number of elderly patients, sex, and aneurysm locations. No between-group difference was identified in terms of the intradural procedural time, retraction-induced cortical injury, postoperative electrolyte imbalance, symptomatic infarction, and postoperative epidural hematomas. However, the patient group without mannitol administration showed a significantly lower incidence of chronic subdural hematomas (CSDHs) >50 mL (13.3% vs. 3.1%, P = 0.010). Moreover, a multivariate analysis revealed that an advanced age (P = 0.019), male sex (P <0.001), and mannitol administration (P = 0.040) were all statistically significant risk factors for a postoperative CSDH >50 mL following unruptured aneurysm surgery.

CONCLUSIONS

Withholding the administration of mannitol during a pterional or modified procedure for unruptured aneurysms was found to reduce the postoperative occurrence of a CSDH without increasing the operative difficulties or other postoperative complications.

Procedural Clinical Complications, Case-Fatality Risks, and Risk Factors in Endovascular and Neurosurgical Treatment of Unruptured Intracranial Aneurysms: A Systematic Review and Meta-analysis

Importance

The risk of procedural clinical complications and the case-fatality rate (CFR) from preventive treatment of unruptured intracranial aneurysms varies between studies and may depend on treatment modality and risk factors.

Objective

To assess current procedural clinical 30-day complications and the CFR from endovascular treatment (EVT) and neurosurgical treatment (NST) of unruptured intracranial aneurysms and risk factors of clinical complications.

Data Sources

We searched PubMed, Excerpta Medica Database, and the Cochrane Database for studies published between January 1, 2011, and January 1, 2017.

Study Selection

Studies reporting on clinical complications, the CFR, and risk factors, including 50 patients or more undergoing EVT or NST for saccular unruptured intracranial aneurysms after January 1, 2000, were eligible.

Data Extraction and Synthesis

Per treatment modality, we analyzed clinical complication risk and the CFR with mixed-effects logistic regression models for dichotomous data. For studies reporting data on complication risk factors, we obtained risk ratios (RRs) or odds ratios (ORs) with 95% CIs and pooled risk estimates with weighted random-effects models.

Main Outcomes and Measures

Clinical complications within 30 days and the CFR.

Results

We included 114 studies (106 433 patients with 108 263 aneurysms). For EVT (74 studies), the pooled clinical complication risk was 4.96% (95% CI, 4.00%-6.12%), and the CFR was 0.30% (95% CI, 0.20%-0.40%). Factors associated with complications from EVT were female sex (pooled OR, 1.06 [95% CI, 1.01-1.11]), diabetes (OR, 1.81 [95% CI, 1.05-3.13]), hyperlipidemia (OR, 1.76 [95% CI, 1.3-2.37]), cardiac comorbidity (OR, 2.27 [95% CI, 1.53-3.37]), wide aneurysm neck (>4 mm or dome-to-neck ratio >1.5; OR, 1.71 [95% CI, 1.38-2.11]), posterior circulation aneurysm (OR, 1.42 [95% CI, 1.15-1.74]), stent-assisted coiling (OR, 1.82 [95% CI, 1.16-2.85]), and stenting (OR, 3.43 [95% CI, 1.45-8.09]). For NST (54 studies), the pooled complication risk was 8.34% (95% CI, 6.25%-11.10%) and the CFR was 0.10% (95% CI, 0.00%-0.20%). Factors associated with complications from NST were age (OR per year increase, 1.02 [95% CI, 1.01-1.02]), female sex (OR, 0.43 [95% CI, 0.32-0.85]), coagulopathy (OR, 2.14 [95% CI, 1.13-4.06]), use of anticoagulation (OR, 6.36 [95% CI, 2.55-15.85]), smoking (OR, 1.95 [95% CI, 1.36-2.79]), hypertension (OR, 1.45 [95% CI, 1.03-2.03]), diabetes (OR, 2.38 [95% CI, 1.54-3.67]), congestive heart failure (OR, 2.71 [95% CI, 1.57-4.69]), posterior aneurysm location (OR, 7.25 [95% CI, 3.70-14.20]), and aneurysm calcification (OR, 2.89 [95% CI, 1.35-6.18]).

Conclusions and Relevance

This study identifies risk factors for procedural complications. Large data sets with individual patient data are needed to develop and validate prediction scores for absolute complication risks and CFRs from EVT and NST modalities.

Study of Incidence and Factors: Risk and Preventive, of Chronic Subdural Hematoma/hygroma in Clipped Patients of Unruptured Intracranial Aneurysms - An Institutional Experience

Introduction

One of the underreported complications of clipping of unruptured aneurysm is chronic subdural hematoma/hygroma (CSDH). It can cause sudden deterioration and might need emergency evacuation. Recently, very few papers have studied its incidence and predisposing factors. We are reporting our institutional experience of it along with the study of its risk factors and possible pathogenesis.

Methodology

Totally 91 postoperative patients of unruptured aneurysms were retrospectively analyzed. Totally 21 patients had CSDH who were operated. In rest seventy patients, there was no CSDH.

Results

Male sex, old age, anticoagulant use, presence of pneumocephalus and dead space were significantly associated with occurrence of CSDH, whereas arachnoidoplasty significantly protected against it. There was no significant relation of CSDH with Gorei-san use.

Conclusions

We recommend arachnoidoplasty should be carried out in all patients of clipping of unruptured aneurysm. Male patients or/and patients with dead space with pneumocephalus must be given extra attention like avoiding any dead space in postoperative period, doing arachnoidoplasty and regular follow up till 1^st year.

Modified Arachnoid Plasty Reduces Chronic Subdural Hematoma after Unruptured Aneurysm Clipping : Technical Note

Objective

Chronic subdural hematoma (CSDH) is a rare complication of unruptured intracranial aneurysm (UIA) clipping surgery. To prevent postoperative CSDH by reducing subdural fluid collection, we applied the modified arachnoid plasty (MAP) during the UIA clipping surgery to seal the dissected arachnoid plane.

Methods

This retrospective study included 286 patients enrolled from July 2012 to May 2015. We performed arachnoid plasty in all patients, with MAP used after June 17, 2014. Patients were divided into two groups (non-MAP vs. MAP), and by using uni- and multivariate analyses, baseline characteristics, and relationships with postoperative CSDH between the two groups were analyzed. The degree of preoperative brain atrophy was estimated using the bicaudate ratio (BCR) index.

Results

Ten patients (3.5%) among 286 patients had postoperative CSDH after clipping. Nine (3.1%) were in the non-MAP group, and one (0.9%) was in the MAP group. The higher BCR index showed statistical significance with occurrence of postoperative CSDH in both uni- (p=0.018) and multivariate (p=0.012; odds ratio [OR], 8.547; 95% confidence interval [CI], 1.616–45.455) analyses. MAP was associated with a lower risk of postoperative CSDH (p=0.022; OR, 0.068; 95% CI, 0.007–0.683).

Conclusion

This study shows that the degree of preoperative brain atrophy is associated with an increased occurrence of CSDH after clipping and that MAP could help reduce the risk of postoperative CSDH after unruptured aneurysm clipping via a lateral supraorbital approach.

Postoperative Subdural Air Collection Is a Risk Factor for Chronic Subdural Hematoma after Surgical Clipping of Cerebral Aneurysms

The precise mechanism of the development of chronic subdural hematoma (CSDH) as a postoperative complication after aneurysmal clipping remains unclear. The purpose of this study was to identify the independent risk factors for CSDH after craniotomy for aneurysmal clipping and to elucidate the relationship between CSDH and subdural air (SDA) collection immediately after surgery. The medical records and radiologic data of 344 patients who underwent surgical clipping of unruptured aneurysms from July 2010 to July 2016 were retrospectively evaluated. Patient characteristics, aneurysm characteristics, and operation data were statistically analyzed to reveal their relationships with CSDH development. Among the 344 patients, 46 (13.4%) developed CSDH and 13 (3.8%) required subsequent burr-hole surgery for evacuation and irrigation. Multivariate analyses showed that advanced age (P < 0.0001), male sex (P = 0.035), and surgical clipping of multiple aneurysms (P = 0.037) were independent preoperative predictors of CSDH development. Advanced age (P = 0.0005) and postoperative SDA after clipping surgery (P < 0.0001) were independent postoperative predictors of CSDH development. Postoperative SDA and CSDH were not associated with the individual surgeon or operation time. Postoperative severe SDA was significantly associated with the ipsilateral development of CSDH, irrespective of the side of craniotomy. Postoperative SDA is an independent risk factor for CSDH after surgical clipping of unruptured aneurysms and is as important as advanced age, male sex, and surgical clipping of multiple aneurysms in predicting CSDH.

Subdural Fluid Collection After the Clipping of Unruptured Intracranial Aneurysms: Its Clinical Course and Significance

OBJECTIVE

We evaluated the clinical course and significance of postoperative subdural fluid collection (SFC) and identified the patients who were at risk of developing postoperative chronic subdural hematoma (CSDH) after the clipping of unruptured intracranial aneurysms (UIAs).

METHODS

Between January 2012 and June 2014, we retrospectively reviewed 298 patients with UIAs treated by microsurgical clipping. Among them, 257 patients were enrolled in the present study. Subdural lesions (SDLs) were defined as SFC at 1-month follow-up computed tomography (CT) and a CSDH at any time within 1 month after the clipping of UIAs. We examined the volume changes, Hounsfield unit (HU) values, and the end results of SFC in serial CT scans.

RESULTS

The incidence of postoperative CSDH that needed burr hole surgery was 2.5%. Changes in SFC volume that occurred within 1 week of surgery were a risk factor for the occurrence of SDL at the 1-month follow-up CT (odds ratio 34.039; P < 0.001). The corrected average HU value of SCF (cut-off value: 11.9, with a sensitivity of 83.3% and specificity of 73.7%) on postoperative day 7 was an independent risk factor for development of a CSDH at the 1-month follow-up CT (odds ratio 19.261; P = 0.003).

CONCLUSIONS

SDLs seen during 1-month follow-up may be associated with the occurrence of increased SFC volume within a week after the clipping of UIAs. The corrected average HU value of the SFC on postoperative day 7 was the only risk factor for the development of CSDHs at 1-month follow-up CT.

Efficacy of Arachnoid-Plasty on Chronic Subdural Hematoma Following Surgical Clipping of Unruptured Intracranial Aneurysms

BACKGROUND

We aimed to elucidate the effects of arachnoid plasty (ARP) on chronic subdural hematoma (CSDH) occurrence following clipping surgery.

METHODS

In total 217 patients (ARP, n = 97; non-ARP, n = 120) who had undergone unruptured intracranial aneurysm (UIA) surgical clipping via the pterional approach were retrospectively assessed. Predisposing factors for CSDH development following the surgery were investigated. Thickness and volume of the subdural fluid collection (SDFC) were measured to determine whether ARP affects postoperative SDFC.

RESULTS

The occurrence of postoperative CSDH was higher in patients without ARP compared to those with ARP (12.5 vs. 3.1%; P = 0.01). In multivariate analyses, having an SDFC volume ≥15 mL on postoperative day (POD) 8, (odds ratio [OR] = 15.113; range = 3.159-72.290), and male sex (OR = 4.274; range = 1.291-14.148) were identified as independent predictive factors. Having had ARP (OR = 0.228; range = 0.056-0.927) was, as an independent variable, negatively correlated with the occurrence of CSDH (P < 0.05). Moreover, SDFC volume ≥15 ml on POD 8 was significantly less common in the ARP group compared with the non-ARP group (P = 0.03).

CONCLUSION

Patients who underwent ARPs developed fewer CSDHs following UIA clipping surgery. The factors that predicted the development of CSDH included male sex, SDFC volume on POD 8, and ARP. In addition, the ARP patients had lower SDFC volumes (<15 mL). These findings suggested that ARP reduced the incidence of CSDHs after surgical clippings in patients with unruptured aneurysms.

Incidence and risk factors of subdural hematoma after intraoperative cerebrospinal fluid leakage during the transsphenoidal approach

PURPOSE

The transsphenoidal approach (TSA) is regarded as the first line of treatment for sellar and suprasellar lesions. There are only few case reports of postoperative subdural hematoma after TSA and extended transsphenoidal approach (eTSA), and the detailed incidence and risk factors for this complication are still unknown. We reviewed the incidence and risk factors for subdural hematoma after TSA and eTSA.

METHODS

Between January 1, 2013 and December 31, 2014, 165 consecutive patients underwent TSA or eTSA at Nagoya University Hospital and Nagoya Daini Red Cross Hospital. Fifty-one patients experienced intraoperative CSF leakage. Postoperative subdural hematoma was observed in 10 patients, all of whom experienced intraoperative CSF leakage. We reviewed clinical data including CT and MR images and examined factors related to subdural hematoma among patients with intraoperative CSF leakage.

RESULTS

In univariate statistical analyses, risk factors for postoperative subdural hematoma were advanced age, high Evans' index, and preoperative hypopituitarism. These factors were also significant in the multivariate logistic regression analysis. There were no statistical differences in sex, tumor size, approach methods, preoperative diabetes insipidus, or degree of intraoperative CSF leakage.

CONCLUSIONS

The incidence of postoperative subdural hematoma after intraoperative CSF leakage during TSA and eTSA was higher than the incidence reported in patients after craniotomy. Intraoperative CSF leakage should be avoided as much as possible, especially in patients with brain atrophy and/or enlargement of the ventricular system, even if the intent of the reconstruction technique is authenticity. In addition, patients with hypopituitarism should be carefully followed up after surgery.

Predicting Factors of Chronic Subdural Hematoma Following Surgical Clipping in Unruptured and Ruptured Intracranial Aneurysm

Objective

The aim of this study is to analyze the differences in the incidence, predicting factors, and clinical course of chronic subdural hematoma (CSDH) following surgical clipping between unruptured (UIA) and ruptured intracranial aneurysm (RIA).

Methods

We conducted a retrospective analysis of 752 patients (UIA : 368 and RIA : 384) who underwent surgical clipping during 8 years. The incidence and predicting factors of CSDH development in the UIA and RIA were compared according to medical records and radiological data.

Results

The incidence of postoperative CSDH was higher in the UIA (10.9%) than in the RIA (3.1%) (p=0.000). In multivariate analysis, a high Hounsfield (HF) unit (blood clots) for subdural fluid collection (SFC), persistence of SFC ≥5 mm and male sex in the UIA and A high HF unit for SFC and SFC ≥5 mm without progression to hydrocephalus in the RIA were identified as the independent predicting factors for CSDH development (p<0.05).

Conclusion

There were differences in the incidence and predicting factors for CSDH following surgical clipping between UIA and RIA. Blood clots in the subdural space and persistence of SFC ≥5 mm were predicting factors in both UIA and RIA. However, progression to hydrocephalus may have in part contributed to low CSDH development in the RIA. We suggest that cleaning of blood clots in the subdural space and efforts to minimize SFC ≥5 mm at the end of surgery is helpful to prevent CSDH following aneurysmal clipping.

Chronic Subdural Hematoma in the Aged, Trauma or Degeneration?

Chronic subdural hematomas (CSHs) are generally regarded to be a traumatic lesion. It was regarded as a stroke in 17th century, an inflammatory disease in 19th century. From 20th century, it became a traumatic lesion. CSH frequently occur after a trauma, however, it cannot occur when there is no enough subdural space even after a severe head injury. CSH may occur without trauma, when there is sufficient subdural space. The author tried to investigate trends in the causation of CSH. By a review of literature, the author suggested a different view on the causation of CSH. CSH usually originated from either a subdural hygroma or an acute subdural hematoma. Development of CSH starts from the separation of the dural border cell (DBC) layer, which induces proliferation of DBCs with production of neomembrane. Capillaries will follow along the neomembrane. Hemorrhage would occur into the subdural fluid either by tearing of bridge veins or repeated microhemorrhage from the neomembrane. That is the mechanism of hematoma enlargement. Trauma or bleeding tendency may precipitate development of CSH, however, it cannot lead CSH, if there is no sufficient subdural space. The key determinant for development of CSH is a sufficient subdural space, in other words, brain atrophy. The most common and universal cause of brain atrophy is the aging. Modifying Virchow's description, CSH is sometimes traumatic, but most often caused by degeneration of the brain. Now, it is reasonable that degeneration of brain might play pivotal role in development of CSH in the aged persons.

Postoperative subdural hygroma and chronic subdural hematoma after unruptured aneurysm surgery: age, sex, and aneurysm location as independent risk factors

OBJECTIVE

This study investigated the incidence and risk factors for the postoperative occurrence of subdural complications, such as a subdural hygroma and resultant chronic subdural hematoma (CSDH), following surgical clipping of an unruptured aneurysm. The critical age affecting such occurrences and follow-up results were also examined.

METHODS

The case series included 364 consecutive patients who underwent aneurysm clipping via a pterional or superciliary keyhole approach for an unruptured saccular aneurysm in the anterior cerebral circulation between 2007 and 2013. The subdural hygromas were identified based on CT scans 6-9 weeks after surgery, and the volumes were measured using volumetry studies. Until their complete resolution, all the subdural hygromas were followed using CT scans every 1-2 months. Meanwhile, the CSDHs were classified as nonoperative or operative lesions that were treated by bur-hole drainage. The age and sex of the patients, aneurysm location, history of a subarachnoid hemorrhage (SAH), and surgical approach (pterional vs superciliary) were all analyzed regarding the postoperative occurrence of a subdural hygroma or CSDH. The follow-up results of the subdural complications were also investigated.

RESULTS

Seventy patients (19.2%) developed a subdural hygroma or CSDH. The results of a multivariate analysis showed that advanced age (p = 0.003), male sex (p < 0.001), middle cerebral artery (MCA) aneurysm (p = 0.045), and multiple concomitant aneurysms at the MCA and anterior communicating artery (ACoA) (p < 0.001) were all significant risk factors of a subdural hygroma and CSDH. In addition, a receiver operating characteristic (ROC) curve analysis revealed a cut-off age of > 60 years, which achieved a 70% sensitivity and 69% specificity with regard to predicting such subdural complications. The female patients ≤ 60 years of age showed a negligible incidence of subdural complications for all aneurysm groups, whereas the male patients > 60 years of age showed the highest incidence of subdural complications at 50%-100%, according to the aneurysm location. The subdural hygromas detected 6-9 weeks postoperatively showed different follow-up results, according to the severity. The subdural hygromas that converted to a CSDH were larger in volume than the subdural hygromas that resolved spontaneously (28.4 ± 16.8 ml vs 59.6 ± 38.4 ml, p = 0.003). Conversion to a CSDH was observed in 31.3% (5 of 16), 64.3% (9 of 14), and 83.3% (5 of 6) of the patients with mild, moderate, and severe subdural hygromas, respectively.

CONCLUSIONS

Advanced age, male sex, and an aneurysm location requiring extensive arachnoid dissection (MCA aneurysms and multiple concomitant aneurysms at the MCA and ACoA) are all correlated with the occurrence of a subdural hygroma and CSDH after unruptured aneurysm surgery. The critical age affecting such an occurrence is 60 years.

Intraoperative Arachnoid Plasty Has Possibility to Prevent Chronic Subdural Hematoma after Surgery for Unruptured Cerebral Aneurysms

Some patients develop chronic subdural hematomas (CSDHs) after the clipping/coating of unruptured aneurysms. The risk factors are not well understood and while no preventive methods are currently available, arachnoid plasty (ARP) may intercept the development of postoperative CSDH. We investigated the risk factors for CSDH and the usefulness of ARP to prevent postoperative CSDH. Between January 2009 and June 2013, 393 patients underwent 416 aneurysm surgeries via the pterional approach at Kushiro Kojinkai Memorial Hospital. Of these, 394 aneurysms (371 patients) were included in this study. Using multivariate analysis we evaluated the relationship between the patient demographics and clinical characteristics, and the development of postoperative symptomatic CSDH. We also studied the effect of ARP performed during aneurysm surgery. We found that symptomatic CSDH developed after 20 (5.1%) of the 394 operations; it was addressed by burr hole surgery and evacuation/irrigation. Male gender, advanced age, and oral anticoagulant therapy were significant risk factors for CSDH. Additive ARP, performed in the course of 132 surgeries (33.5%) was found to be a significant negative risk factor. The incidence of CSDH was significantly lower in patients who had undergone ARP than in patients who had not undergone it (0.8% vs. 7.3%, p < 0.01). We first report that ARP is useful for the prevention of CSDH in patients treated by aneurysm surgery.

Incidence and risk factors of chronic subdural hematoma after surgical clipping for unruptured anterior circulation aneurysms

OBJECTIVE

Chronic subdural hematoma (CSDH) is a rare complication of unruptured aneurysm clipping surgery. The purpose of this study was to identify the incidence and risk factors of postoperative CSDH after surgical clipping for unruptured anterior circulation aneurysms.

METHODS

This retrospective study included 518 patients from a single tertiary institute from January 2008 to December 2013. CSDH was defined as subdural hemorrhage which needed surgical treatment. The degree of brain atrophy was estimated using the bicaudate ratio (BCR) index. We used uni- and multivariate analyses to identify risk factors correlated with CSDH.

RESULTS

Sixteen (3.1%) patients experienced postoperative CSDH that required burr hole drainage surgery. In univariate analyses, male gender (p<0.001), size of aneurysm (p=0.030), higher BCR index (p=0.004), and the use of antithrombotic medication (p=0.006) were associated with postoperative CSDH. In multivariate analyses using logistic regression test, male gender [odds ratio (OR) 4.037, range 1.287-12.688], high BCR index (OR 5.376, range 1.170-25.000), and the use of antithrombotic medication (OR 4.854, range 1.658-14.085) were associated with postoperative CSDH (p<0.05). Postoperative subdural fluid collection and arachnoid plasty were not showed statistically significant difference in this study.

CONCLUSION

The incidence of CSDH was 3.1% in unruptured anterior circulation aneurysm surgery. This study shows that male gender, degree of brain atrophy, and the use of antithrombotic medication were associated with postoperative CSDH.