Efficacy and safety of the pterional keyhole approach for the treatment of anterior circulation aneurysms

The Pterional Keyhole Craniotomy Approach: A Historical Perspective

The pterional craniotomy is a workhorse of cranial surgery that provides access to the anterior and middle fossae. However, newer "keyhole" approaches, such as the micropterional or pterional keyhole craniotomy (PKC) can offer similar exposure for many pathologies while reducing surgical morbidity. The PKC is associated with shorter hospitalizations, reduced operative time, and superior cosmetic outcomes. Furthermore, it represents an ongoing trend toward smaller craniotomy size for elective cranial procedures. In this historical vignette, we trace the history of the PKC from its origins to its current role in the neurosurgeon's armamentarium.

Morphological types and localization patterns of pterion in the skulls of adults from southeastern China

PURPOSE

To study the morphological types and relative location of the pterion and its precise relationship with the middle meningeal artery (MMA) in the skulls of adults from southeastern China.

METHODS

Dry skulls (n = 250) of adults were obtained from a university specimen bank and analyzed. The morphological types of the pterions were observed. The distances from the center of the external pterion (Pec) to the relevant intracranial and extracranial marker points were measured using a digital vernier caliper. The anterior, middle, and posterior end points of the external pterion were drilled perpendicular to the bone surface. The precise relationships of the external pterion with the internal pterion and the groove of the frontal branch of the MMA were observed and measured after sawing the skull.

RESULTS

The morphological types of the pterion in the skulls of adults from southeastern China were sphenoparietal suture (SP) (85%), epipteric (12.4%), frontotemporal suture (1.4%), and stellate (1.2%) types. The mean widths of the external and internal pterions were R, 10.68 ± 4.22 mm; L, 11.13 ± 4.40 mm and R, 14.66 ± 4.04 mm; L, 14.14 ± 4.29 mm, respectively, and the width of the internal pterion was slightly longer than that of the external (P < 0.05). No significant difference in pterion width was found between the genders or sides of the skull (both P > 0.05). The distances from the Pec to the posterolateral aspect of the frontozygomatic suture, zygomatic process of the frontal bone, midpoint of the zygomatic arch, and external acoustic meatus were 29.95 ± 3.75 mm, 34.88 ± 4.08 mm, 40.86 ± 3.59 mm, and 53.79 ± 3.82 mm, respectively. These distances were slightly longer on the right side of the skull than on the left side (P < 0.01) and longer in men than in women (P < 0.01). The distances from the Pec to the frontal crest, optic canal, and anterior clinoid process were 62.79 ± 1.15 mm, 45.39 ± 2.48 mm, and 45.47 ± 2.05 mm, respectively. The external and internal pterions were not on the same level, and all the internal pterions were located below the external ones. In the vast majority of the skulls, the groove of the frontal branch of the MMA passed through the posterior end of the external pterion (Pep) or the area between the Pec and Pep.

CONCLUSION

The morphology of the pterion in the skulls of adults from southeastern China is predominantly of the SP type, mostly symmetrically distributed. The distance from the pterion to the extracranially relevant marker points differs among the ethnic groups, between the genders, and between the sides of the skull. All the internal pterions are located below the external ones. Most of the frontal branch of the MMA is located below the mid-posterior segment of the lateral pterion. The characterization of the morphology, the relative position of the pterion and the precise relationship of this structure with the MMA in the skulls of adults from southeastern China may provide an anatomical basis for teaching and clinical practices.

Reconstruction clipping of ruptured anterior circulation aneurysms via supraorbital lateral keyhole approach

Background

Intracranial aneurysm (IA) is a serious disease. Analyze and review the cases of anterior circulation ruptured IA by supraorbital lateral keyhole approach, and summarize the experiences of this approach.

Methods

Retrospective analysis of 16 cases of ruptured anterior circulation IA in our department from January 2019 to June 2020, CT angiography (CTA) was performed before operation. Analyzing the IA’s parameters by 3D-CT reconstruction. The IA was clipped by supraorbital lateral keyhole approach combined with the 3D-skull reconstruction. Extraventricular drainage was performed before craniotomy. Intraoperative neurophysiological monitoring was performed during the operation. After operation, fluorescein angiography and vascular ultrasound were performed to check the clipping effect. Intracranial pressure monitor was performed postoperatively. CTA was reexamined one week after operation. The modified Rankin Scale (MRS) was performed 6 months after operation.

Results

There were 7 males (43.8%) and 9 females (56.2%), and the average age is 52.31 ± 11.12 years old. Among them, 11 patients (68.8%) were anterior communicating artery aneurysms and 5 (31.2%) were middle cerebral artery aneurysms. All patients were out of hospital within 10 days without any death, without cerebral infarction, cerebrospinal fluid leakage and neurological impairments. About mRS score, after 6 months follow-up, 8 cases (50%) had 0 point, 4 cases (25%) had 1 point, and 4 cases (25%) had 2 points.

Conclusions

For ruptured anterior circulation IA, the supraorbital lateral keyhole approach combined with ventricular drainage, intraoperative electrophysiological monitoring, and intraoperative vascular ultrasound is a safe and minimally invasive treatment. The application of reconstruction clipping can reconstruct the diameter of parent vessel and reduce the recurrence rate of IA.

Eyebrow incision with a crescent-shaped orbital rim craniotomy for microscopic and endoscopic transorbital approach to the anterior and middle cranial fossa: A cadaveric study and case presentation

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The transorbital approach combining eyebrow incision and crescent-shaped craniotomy increases the surgical freedom to access the anterior and middle skull-base.

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The technic allows the use of both endoscope and microscope.

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The concept is at the crossroad between the supraorbital keyhole and endoscopic trans-orbital approach.

Keyhole Approach for Clipping Anterior Circulation Aneurysms: Clinical Outcomes and Technical Note

Purpose: Keyhole craniotomy is a minimally invasive approach for the treatment of anterior circulation aneurysm. In this study, we evaluated the benefits and value of the keyhole approach by analyzing the surgical results in 235 patients with anterior circulation aneurysm treated by the keyhole approach and identifying lessons learned from addressing various complications in this approach.

Patients and Methods: This was a retrospective study in a single institution of 235 surgical patients with 248 anterior circulation aneurysms who had the supraorbital keyhole approach (SKA) or pterional keyhole approach (PKA) between January 2016 and January 2021. The modified Rankin Scale (mRS) was used to measure long-term results during follow up.

Results: All 235 patients' aneurysms were fully clamped and have not recurred. Among them, 31 (13.2%) had intraoperative aneurysm rupture, 8 (3.4%) had cerebral vascular spasm, and 4 (1.7%) had intraoperative brain edema. There were seven (3.0%) cases of postoperative infection, eight (3.4%) cases of postoperative cerebral infarction, one (0.4%) case of postoperative hematoma, and two (0.8%) patients had some form of cognitive impairment after surgery. Follow up after surgery demonstrated that 189 out of the 235 patients (80.4%) had favorable outcomes (mRS score 0–2), and 43 (18.3%) had poor outcomes (mRS from 3–5). There were three deaths (1.28%).

Conclusions: The keyhole approach has a quick postoperative recovery, a mild postoperative response, and a good surgical outcome. Our findings indicate that the keyhole approach is a safe and effective surgical method for the treatment of anterior circulation aneurysm.

Minimally Invasive Subfrontal Approach: How to Make it Safe and Effective from the Olfactory Groove to the Mesial Temporal Lobe

BACKGROUND

 Different surgical approaches have been developed to manage lesions of the anterior and middle skull base areas. Frontal, pterional, bifrontal, and fronto-orbito-zygomatic approaches are traditionally used to reach these regions. With advancements in the neurosurgical field, skull opening should be simple and as minimally invasive as possible, tailored on the surgical corridor to the target. The supraorbital approach and the "keyhole" concept have been introduced and popularized by Axel Perneczky starting from 1998 and are now considered a part of everyday practice. The extended possibilities of this surgical route, considering the reachable targets and surgical limits, are described and systematically analyzed, including a description of the salient surgical anatomy, presenting different illustrative cases.

METHODS AND RESULTS

 Different illustrative cases are presented and discussed to underline the potentials and limits of the minimally invasive subfrontal approach (MISFA) and the possibilities to tailoring the craniotomy on the basis of the targets: extra-axial lesions with different localizations (anterior roof of the orbit, olfactory groove, tuberculum sellae, medial third of the sphenoid wing, anterior and posterior clinoid process), deeper intra-axial lesions (gyrus rectus, medial temporal lobe-uncus-amygdala-anterior hippocampus), and vascular lesions (anterior communicating aneurysm). Each case has been preoperatively planned considering the anatomical and radiologic features and using virtual simulation software to tailor the best possible corridor to reach the surgical target.

CONCLUSIONS

 The MISFA is a safe multicorridor approach that can be used efficiently to manage lesions of the anterior and middle skull base areas with extremely low approach-related morbidity.

How Safe and Effective Is Shifting from Pterional to Supraorbital Keyhole Approach for Clipping Ruptured Anterior Circulation Aneurysms? A Surgeon's Transition Phase Comparative Study

Background  Comparative studies between standard pterional and supraorbital keyhole approaches for aneurysms had potential biases with the heterogeneity of patient selection, differences among surgeons, or varying expertise across the surgeon’s learning curve. This is a study of a surgeon’s transition from pterional to keyhole approach for early clipping of selected consecutive ruptured anterior circulation aneurysms.

Methods  Patients more than 18 years, presenting within 72 hours of ictus, in good clinical grades 1 to 3, no midline shift, with saccular aneurysms less than 25 mm at either communicating segment of internal carotid artery, anterior communicating artery, or middle cerebral artery segment till bifurcation were studied between the last 25 cases of pterional and first 25 cases of the keyhole, for the intraoperative and postoperative surgical outcome parameters.

Results  There was no significant difference among baseline parameters, including the location of aneurysms across both groups. While only four cases of pterional had an intraoperative ventricular puncture, the lumbar drain was electively inserted in all keyhole patients. The intraoperative parameters, such as a dural tear, adequate parent vessel exposure, temporary clipping, and intraoperative rupture, did not show any significant difference. None had immediate postoperative deficits. While delayed cerebral ischemia and wound complaints were similar in both groups, temporal hollowing and chewing difficulty were significantly more in pterional patients( p = 0.01).

Conclusion  A surgeon experienced in pterional approach can comfortably and safely shift to the keyhole for early clipping of selected ruptured aneurysms less than 25 mm, with a comparable surgical outcome but better cosmesis and mastication.

The Keyhole Approach in Anterior Circulation Aneurysm - Current Indication and Limitation with Review of Literature

Introduction:

The keyhole approach has been an emerging technique for cerebral aneurysm surgery in the past two decades. The preoperative simulation and tailored-made approach for each patient make feasible to clip many cerebral aneurysms via keyhole approach. In our study, we reviewed the previous experiences of the keyhole approach, related specifically for anterior circulation aneurysm.

Material and Methods:

The comprehensive literature review was performed on PubMed, Google Scholar, ScienceDirect, and various neurosurgery and neurology journals. Then, each manuscript's reference list was reviewed for the potential relevant article. The data of total 17 articles, which met our inclusion criteria included for the final review.

Results:

It was found that the anterior communicating artery, middle cerebral artery, and internal carotid- posterior communicating aneurysms were the most common locations treated by keyhole approach. The size of an aneurysm was <10 mm in most of the studies. Many studies treated multiple aneurysms by single keyhole approach.

Conclusion:

The keyhole approach has shown benefit in term of satisfactory aneurysmal occlusion rate, short operative time, less blood loss, short hospital stay, and good overall surgical outcome.

Meta-Analysis of Pterional Versus Supraorbital Keyhole Approach for Clipping Intracranial Aneurysms: Direct Comparison of Approach-Related Complications

BACKGROUND

The supraorbital keyhole approach (SKA) and pterional approach (PA) have been recommended for clipping intracranial aneurysms (IAs). We conducted a meta-analysis to systematically and comprehensively compare the clinical outcomes between the 2 approaches.

METHODS

We retrieved potential academic studies that had compared the clinical outcomes of SKA and PA for clipping IAs from the Cochrane Library, Medline, PubMed, and EMBASE databases. The references of the identified studies were carefully reviewed to ensure that all available documents had been included in the present study. The meta-analysis was conducted in accordance with the acknowledged PRISMA (prioritized reported items for systematic review and meta-analysis) guidelines.

RESULTS

A total of 8 studies with 1016 participants were included in our study. Of these 1016 patients with IAs, 518 were assigned to the SKA group and 498 to the PA group. Our results showed that the SKA is preferable for clipping IAs compared with the PA because of its shorter operative time (weighted mean difference, -3.163; 95% confidence interval [CI], -5.577 to -0.749; P = 0.01) and length of stay, especially for the patients with unruptured IAs (weighted mean difference, -52.107; 95% CI, -81.597 to -22.618). However, a lower risk of postoperative infection was found in the SKA group (4.6% vs. 8.5%; odds ratio, 0.398; 95% CI, 0.186-0.850; P = 0.017), which seemed to derive from the ruptured IAs (OR, 0.330; 95% CI, 0.136-0.800; P = 0.014). However, no significant difference was found in the incidence of frontal sinus opening, completed occlusion, procedural complications, intraoperative rupture, postoperative hematoma, or cerebral vessel spasm.

CONCLUSIONS

The SKA was associated with a shorter length of stay and operation time and a lower risk of postoperative infection. Hence, the SKA seems to be equally effective and safe for clipping IAs compared with PA and should be recommended for surgeons who have acquired sufficient experience with this technique owing to its advantages compared with the PA.

Neuroendoscopic Surgery versus Craniotomy for Supratentorial Hypertensive Intracerebral Hemorrhage: A Systematic Review and Meta-Analysis

BACKGROUND

No consensus has been achieved on the superiority between neuroendoscopy (NE) and craniotomy (CT) for the treatment of supratentorial hypertensive intracerebral hemorrhage (HICH). The purpose of this study is to analyze the efficacy and safety of NE versus CT for supratentorial HICH.

METHODS

A systematic search of English databases (PubMed, Embase, the Cochrane Library, and Web of Science) was performed to identify related studies reported from September 1994 to June 2019. The Newcastle-Ottawa Scale and the Cochrane Reviewer's Handbook 5.0.0 were separately used to evaluate the quality of the included observational studies and randomized controlled trials. RevMan 5.3 software was adopted to conduct the meta-analysis. The outcome measures included the primary and secondary outcomes. Subgroup analysis was performed to explore the impact of year of publication, initial Glasgow Coma Scale (GCS) score, age, time to surgery, hematoma volume, and surgical methods on the outcome measures.

RESULTS

Fifteen studies (3 randomized controlled trials and 12 observational studies), comprising 1859 patients with supratentorial HICH, were included in this meta-analysis. The pooled results showed that NE could increase the good functional outcome (GFO) (P < 0.0003) and hematoma evacuation rate (P = 0.0007) and reduce the mortality (P < 0.00001), blood loss (P = 0.004), operation time (P < 0.00001), hospital stays (P = 0.006), and intensive care unit stays (P < 0.0001) compared with CT. In addition, NE could also have a positive effect on preventing postoperative infection (P < 0.00001) and total complications (P < 0.00001). However, in postoperative rebleeding incidence (P = 0.12), no obvious difference was found between the 2 groups. Publication bias was low regarding GFO, mortality, and hematoma evacuation rate. Subgroup analysis suggested that year of publication, initial GCS score, age, hematoma volume, and surgical methods did not affect the hematoma evacuation rate significantly. The difference in mortality was not statistically significant in the subgroup of hematoma volume <50 mL (P = 0.44) and initial GCS score >8 (P = 0.09). In addition, the data suggested that time to surgery and surgical methods might be the important factors affecting GFO and mortality.

CONCLUSIONS

NE might be a safer and more effective surgical method than CT in the treatment of patients with supratentorial HICH. However, because of the existence of some limitations, the safety and validity of NE were weakened. More high-quality trials should be included to verify our conclusion.

Evaluation of temporal muscle trophism in relation to the manipulation time and infiltration of 0.5% isobaric bupivacaine through a pterional approach

INTRODUCTION

There are different techniques for the reconstruction of the temporal muscle (TM) in the pterional approach (PA) in order to avoid and reduce atrophy, it has not been able to avoid it in its entirety. The administration of bupivacaine generates regeneration of muscle fibres. There are no studies in the medical literature that evaluate the time of TM manipulation and the use of bupivacaine for the treatment of atrophy after pterional approach, the present investigation aim is to describe the effects of these variables.

PATIENT AND METHODS

Longitudinal study, including patients from 18-80 years old with pterional approach at 2016-2017. We evaluated the effects of the TM manipulation times and the administration of 0.5% bupivacaine on the trophism and function of TM.

RESULTS

Twenty-nine patients underwent a PA; 16(55.17%) count with criteria for 0.5% bupivacain infiltration. We found a negative correlation between manipulation times and trophism, with no statistically significance (p>.05). We evaluated presurgical and postsurgical index of Helkimo and Fonseca's index, finding an increase of disfunction with statistically significance (p<.05). In patients who were infiltrated with 0.5% bupivacaine we observed a mean difference in the TM's trophism of 0.275±1.18mm, in contrast with no infiltrated which was 2.39±1.30mm (t[27] = -5.118, p=.0001).

CONCLUSIONS

The manipulation of the TM during a pterional approach conditioned an impact on the quality of life according to the disfunction indexes, due to atrophy. This investigation exhibits that de administration of 0.5% bupivacaine during surgery offers a decrease in the TM atrophy.

Keyhole strategy aiming at minimizing hospital stay for surgical clipping of unruptured middle cerebral artery aneurysms

OBJECTIVE

Aneurysms of the middle cerebral artery (MCA) are still most often treated by clipping through standard craniotomy, but a longer hospital stay is one of the main drawbacks of this treatment. The authors developed a pterional keyhole clipping strategy for unruptured MCA aneurysms with the intention of minimizing hospital stay. In this paper, they report on their experience with this approach and analyze the long-term neurological and radiological outcomes.

METHODS

A total of 160 relatively small unruptured MCA aneurysms (mean 6.4 mm) were clipped through the pterional keyhole approach (19–30 mm, mean 24.6 mm) in 149 patients (aged 34–79 years, mean 62 years). Neurological and cognitive function were examined by several scales, including the modified Rankin Scale (mRS) and Mini–Mental State Examination (MMSE). Patients’ level of depression was assessed using the Beck Depression Inventory and Hamilton Depression Scale. The state of clipping was assessed at 1 year and then every few years after the operation.

RESULTS

The mean duration of postoperative hospitalization was 2.3 ± 3.4 days; in 31.3% of the cases, the patients were discharged on the day after the operation (overnight hospital stay) and in 93.2% within 3 days. Of the patients younger than 60 years, 40.4% required only an overnight stay. Complete aneurysm neck clipping was confirmed in 157 cases (98.1%). None of the completely clipped aneurysms showed any recurrence during the mean follow-up period of 5.0 years. The mean length of clinical follow-up was 5.4 years. After 2 (1.3%) of the surgical procedures, the patients showed persistent neurological deficits, defined as mRS score 1, but the overall operative morbidity based on the International Study of Unruptured Intracranial Aneurysms (ISUIA) definition (mRS score ≥ 2 or MMSE score < 24) was 0% at the last examination. Depression scores were significantly improved after surgery, and in 85.6% of the cases the patients were satisfied with their cosmetic results.

CONCLUSIONS

Pterional keyhole clipping is less invasive than clipping via standard craniotomy, minimizes hospital stay, and achieves durable treatment for relatively small unruptured MCA aneurysms.

Comparison of Supraorbital and Pterional Keyhole Approach for Clipping Middle Cerebral Artery Aneurysm: A Chinese Population-Based Study

OBJECTIVE

Keyhole craniotomy is a minimally invasive approach for the treatment of middle cerebral artery (MCA) aneurysms. The aim of this study was to compare the clinical outcome between supraorbital keyhole approach and pterional keyhole approach (PKA) in Chinese patients with MCA aneurysm.

METHODS

Consecutive patients with MCA aneurysms were reviewed between January 2013 and December 2017. Efficacy and safety between PKA and supraorbital keyhole approach were compared. Poor outcome was defined as modified Rankin Scale score of 3-6 at discharge.

RESULTS

This study enrolled 260 patients; 222 (85.4%) had ruptured aneurysm, and 183 (70.4%) received PKA. The distribution of PKA in unruptured and ruptured aneurysms showed no significant difference (P > 0.05). In subgroup analyses, PKA was more likely associated with poor outcome at discharge in patients with unruptured aneurysms (odds ratio = 5.500, 95% confidence interval = 1.013-29.850, P = 0.048), whereas approach selection was not an independent factor predicting poor outcome in patients with ruptured aneurysms (P > 0.05).

CONCLUSIONS

In a Chinese population, supraorbital keyhole approach was superior to PKA in improving outcome in patients with unruptured MCA aneurysms, but the 2 approaches showed comparable outcomes at discharge in patients with ruptured aneurysms.

Experience Using the Pterional Keyhole Approach for the Treatment of Ruptured Intracranial Aneurysms of the Anterior Circulation

BACKGROUND

The pterional keyhole approach is a more recently introduced minimally invasive version of the traditional pterional approach for treating aneurysms of the anterior circulation.

METHODS

In this study, we compared operative parameters and clinical outcomes in patients treated with the pterional keyhole approach and historical controls in whom the traditional pterional approach was used. We reviewer records of 356 patients treated with the pterional keyhole approach between 2009 and 2016, along with those of 301 patients treated via the traditional pterional approach at the same period who served as a control group. The clinical manifestations, surgical details, postoperative complications, and modified Rankin Scale scores in the 2 groups were retrospectively compared.

RESULTS

There were 408 aneurysms in the study group and 362 aneurysms in the control group. In the pterional keyhole group, the total clipping ratio was 93.6%, leaving a remnant/wrapping rate of 6.37%, compared with 93.9% and 6.08%, respectively, in the standard pterional group. In the patients treated via the keyhole approach, the mean bone flap diameter was 4 × 3 cm, mean blood loss was 204 ± 100 mL, mean operation time was 160 ± 57 minutes, and mean length of stay was 8.32 ± 2.72 days, compared with control group parameters of 5 × 6 cm, 284 ± 150 mL, 180 ± 49 minutes, and 11.32 ± 2.48 days, respectively. At a 6-month follow-up, 71.1% had a favorable outcome, 25.8% had a poor outcome, and the mortality was 3.09%, compared with 68.1%, 29.9% and 1.99%, respectively, in the control group.

CONCLUSIONS

The pterional keyhole approach offers shorter operative times, less blood loss, shorter length of stay, and improved cosmesis without sacrificing outcomes compared with traditional pterional craniotomy.

Comparison between frontolateral approach and pterional approach in the surgical treatment of paraclinoid aneurysms

OBJECTIVE

To compare the pterional and frontolateral approach to determine the most effective route for paraclinoid aneurysm surgery.

METHODS

Between June 2010 and December 2015, a total of 176 patients with paraclinoid aneurysm underwent surgical clipping, 96 through the pterional and 80 through the frontolateral approach. We analyzed the two groups and compared demographic, radiologic, and clinical variables including age, sex, aneurysm type,intraoperative rupture rates, operative time,anatomical obstacles,outcome and postoperative complications.

RESULTS

The 2 groups were comparable with respect to baseline characteristics. The mean operation time was also signifcantly shorter in frontolateral group than in the pterion group (204.3 min vs. 264.1 min, p < 0.05). Furthermore, the mean craniotomy area was much smaller in the frontolateral group (1255.4 mm² vs. 2758.5 mm², p < 0.05). No patient experienced rebleeding in either group. In the frontolateral group, the exploration allows enough room for intracranial manipulation with maximal protection of the brain and other intracranial structures.

CONCLUSION

The frontolateral approach is a simple, reliable, and efficient procedure. The frontolateral approach could be a good alternative to the classic pterional approach for the treatment of paraclinoid aneurysms.

Validation of effectiveness of keyhole clipping in nonfrail elderly patients with unruptured intracranial aneurysms

OBJECTIVE

Advanced age is known to be associated with a poor prognosis after surgical clipping of unruptured intracranial aneurysms (UIAs). Keyhole clipping techniques have been introduced for less invasive treatment of UIAs. In this study, the authors compared the complications and clinical and radiological outcomes after keyhole clipping between nonfrail elderly patients (≥ 70 years) and nonelderly patients.

METHODS

Keyhole clipping (either supraorbital or pterional) was performed to treat 260 cases of relatively small (≤ 10 mm) anterior circulation UIAs. There were 62 cases in the nonfrail elderly group (mean age 72.9 ± 2.6 years [± SD]) and 198 cases in the nonelderly group (mean age 59.5 ± 7.6 years). The authors evaluated mortality and morbidity (modified Rankin Scale score > 2 or Mini–Mental State Examination [MMSE] score < 24) at 3 months and 1 year after the operation, the general cognitive function by MMSE at 3 months and 1 year, anxiety and depression by the Beck Depression Inventory (BDI) and Hamilton Rating Scale for Depression (HAM-D) at 3 months, and radiological abnormalities and recurrence at 1 year.

RESULTS

Basic characteristics including comorbidities, frailty, and BDI and HAM-D scores were not significantly different between the 2 groups, whereas the MMSE score was slightly but significantly lower in the elderly group. Aneurysm location, largest diameter, type of keyhole surgery, neck clipping rate, and hospitalization period were not significantly different between the 2 groups. The incidence of chronic subdural hematoma was not significantly higher in the elderly group than in the nonelderly group (8.1% vs 4.5%, p = 0.332); rates of other complications including stroke and epilepsy were not significantly different. Lacunar infarction occurred in 3.2% of the elderly group and 3.0% of the nonelderly group. No patient in the elderly group required re-treatment or demonstrated recurrence of clipped aneurysms. The MMSE score at 3 months significantly improved in the nonelderly group but did not change in the elderly group. The BDI and HAM-D scores at 3 months were significantly improved in both groups. No patient died in either group. The morbidity at 3 months and 1 year in the elderly group (1.6% and 4.8%, respectively) was not significantly different from that in the nonelderly group (2.0% and 1.5%, respectively).

CONCLUSIONS

Keyhole clipping for nonfrail elderly patients with relatively small anterior circulation UIAs did not significantly increase the complication, mortality, or morbidity rate; hospitalization period; or aneurysm recurrence compared with nonelderly patients, and it was associated with improvement in anxiety and depression. Keyhole clipping to treat UIAs in the nonfrail elderly is an effective and long-lasting treatment.

Use of Three-Dimensional Curved-Multiplanar Reconstruction Images for Sylvian Dissection in Microsurgery of Middle Cerebral Artery Aneurysms

PURPOSE

The purpose of this study was to introduce a method of using three-dimensional (3D) curved-multiplanar reconstruction (MPR) images for sylvian dissection during microsurgical treatment of middle cerebral artery (MCA) aneurysms.

MATERIALS AND METHODS

Forty-nine patients who had undergone surgery for MCA aneurysms were enrolled. We obtained the 3D curved-MPR images along the sphenoid ridge using OsiriX MD™ imaging software, compared sylvian dissection time according to several 3D MPR image factors, and investigated the correlations between these images and intraoperative findings.

RESULTS

Utilizing preoperative information of the sylvian fissure (SF) and peri-aneurysmal space on 3D curved-MPR images, we could predict the feasibility of sylvian dissection for a safe surgery. 3D curved-MPR images showed several features: first, perpendicular images to the sylvian surface in the same orientation as the surgeon's view; second, simultaneous visualization of the brain cortex, vessels, and cisternal space; and third, more accurate measurement of various parameters, such as depth of the MCA from the sylvian surface and the location and width of the SFs.

CONCLUSION

In addition to conventional image studies, 3D curved-MPR images seem to provide useful information for Sylvian dissection in the microsurgical treatment of MCA aneurysms.

Superficial Temporal Artery-Sparing Mini-Pterional Approach for Cerebral Aneurysm Surgery

OBJECTIVE

The purposes of this study were to introduce a superficial temporal artery (STA)-sparing mini-pterional approach for the treatment of cerebral aneurysms and review the surgical results of this approach.

METHODS

Between June 2010 and December 2015, we performed the STA-sparing mini-pterional approach for 117 patients with 141 unruptured intracranial aneurysms. We analyzed demographic, radiologic, and clinical variables including age, sex, craniotomy size, aneurysm location, height of STA bifurcation, and postoperative complications.

RESULTS

The mean age of patients was 58.4 years. The height of STA bifurcation from the superior border of the zygomatic arch was 20.5 mm±10.0 (standard deviation [SD]). The craniotomy size was 1051.6 mm²±206.5 (SD). Aneurysm neck clipping was possible in all cases. Intradural anterior clinoidectomy was performed in four cases. Contralateral approaches to aneurysms were adopted for four cases. Surgery-related complications occurred in two cases. Permanent morbidity occurred in one case.

CONCLUSION

Our STA-sparing mini-pterional approach for surgical treatment of cerebral aneurysms is easy to learn and has the advantages of small incision, STA sparing, and a relatively wide surgical field. It may be a good alternative to the conventional pterional approach for treating cerebral aneurysms.

Feasibility and Efficacy of Olfactory Protection Using Gelfoam and Fibrin Glue during Anterior Communicating Artery Aneurysm Surgery

Objective

Patients treated with surgical clipping for anterior communicating artery (A-com) aneurysm often complain of anosmia, which can markedly impede their quality of life. We introduce a simple and useful technique to reduce postoperative olfactory dysfunction in A-com aneurysm surgery.

Methods

We retrospectively reviewed the medical records of patients who underwent surgical clipping for unruptured aneurysm from 2011-2013 by the same senior attending physician. Since March 2012, olfactory protection using gelfoam and fibrin glue was applied in A-com aneurysm surgery. Therefore we categorized patients in two groups from this time-protected group and unprotected group.

Results

Of the 63 enrolled patients, 16 patients showed postoperative olfactory dysfunction-including 8 anosmia patients (protected group : unprotected group=1 : 7) and 8 hyposmia patients (protected group : unprotected group=2 : 6). Thirty five patients who received olfactory protection during surgery showed a lower rate of anosmia (p=0.037, OR 10.516, 95% CI 1.159-95.449) and olfactory dysfunction (p=0.003, OR 8.693, 95% CI 2.138-35.356). Superior direction of the aneurysm was also associated with a risk of olfactory dysfunction (p=0.015, OR 5.535, 95% CI 1.390-22.039).

Conclusion

Superior direction of aneurysm appears associated with postoperative olfactory dysfunction. Olfactory protection using gelfoam and fibrin glue could be a simple, safe, and useful method to preserve olfactory function during A-com aneurysm surgery.

Retractorless Surgery for Anterior Circulation Aneurysms via a Pterional Keyhole Approach

Brain retraction is required during many intracranial procedures to provide more working space. However, it is difficult to avoid brain retraction injury. Here, we report on retractorless surgery for anterior circulation aneurysms via a pterional keyhole approach. All patients undergoing a minimally invasive pterional keyhole approach within 3 days after hemorrhage by the same surgeon were included in the study. Patients were randomly assigned into group I (with the retractorless technique) and group II (with fixed retractors). Data on adequate clipping level, intraoperative ischemia induced by retraction, operation time, brain retraction injury, intraoperative blood loss, intraoperative aneurysm rupture, and modified Rankin Scale were collected for the 2 groups. A consecutive series of 47 patients (21 patients in group I, 26 patients in group II) successfully underwent a minimally invasive pterional keyhole approach. Statistical analysis revealed no significant between-group differences with regard to sex, age, Hunt-Hess grade, adequate clipping level, operation time, intraoperative blood loss, and aneurysm rupture (P > 0.05). However, no intraoperative ischemia was detected in group I, whereas 23.1% (6 of 26) of patients in group II had reversible ischemia. Furthermore, the proportion of brain retraction injuries in group I (5.3%) was lower than that in group II (34.6%). In addition, a better prognosis was obtained in patients who underwent retractorless surgery. With the careful and accurate use of a handheld suction device and operating instruments, the retractorless technique can replace fixed retraction, reduce brain retraction injury, and is applicable to surgeries on anterior circulation aneurysms via pterional keyhole approaches.