The keyhole concept in aneurysm surgery: results of the past 20 years

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.

Transpalpebral approach for microsurgical clipping of an unruptured basilar apex aneurysm: case report and literature review

BACKGROUND AND IMPORTANCE

The supraorbital "keyhole" approach has been described for the treatment of basilar artery aneurysms. Transpalpebral approach (TPA) is an alternative minimally invasive route to aneurysms of the Circle of Willis with excellent functional and cosmetic outcomes.

CLINICAL PRESENTATION

53-years-old female who presented with an incidentally found 6.3 mm BA aneurysm with 3.1 mm neck diameter, admitted to our department of neurovascular surgery. Clipping was performed through TPA, with endoscope assistance and intraoperative ICG angiography. The patient's postoperative course was uneventful and was discharged home on postoperative day 5 without any complications.

CONCLUSION

First time in the literature described keyhole TPA with eyelid incision to BA aneurysm. TPA is technically difficult and requires some experience to work through deep and limited surgical corridor. This technique can be good alternative to traditional fronto-lateral, supraorbital keyhole craniotomies.

Supraorbital eyebrow approach and pterional approach in surgical treatment of ruptured and unruptured aneurysms: a propensity score-matched analysis

The aim of this study is to reveal efficacy and efficiency of the supraorbital eyebrow approach (SEA) in clipping ruptured and unruptured aneurysms where both SEA and pterional approach (PA) are considered feasible by comparing SEA and PA using propensity score matching. A total of 229 patients who underwent surgical clipping of an aneurysm from 2013 to 2022 and met inclusion criteria were recruited in the study. A study group of 67 patients treated via the SEA and a comparison group of 162 patients treated via the PA were formed. Then, the subgroups of 66 patients each, with balanced incoming factors, were analyzed using the propensity score technique. The safety and efficacy endpoints were compared. Successful clipping was achieved in all cases of both groups. There were no patients in the SEA group who required conversion to the standard craniotomy. There were no procedure-related deaths in this series. No patient experienced early or late rebleeding in either group. Mean blood loss volume in the SEA group was lower than in the PA group by approximately 77.5 ml (p < 0.001). There were favorable differences in the SEA group regarding postoperative neurological deficit (p = 0.016), postoperative epileptic seizure rate (p = 0.013), ischemic and hemorrhagic complications (p = 0.028 and 0.0009, respectively), and outcomes (p < 0.001). Patients' satisfaction with cosmetic results measured by the visual analog scale was rated highly in both groups (p = 0.081). For patients where SEA provides adequate exposure, it results in safety and cosmetic outcomes not inferior to the PA.

Minimally invasive craniotomies for lesions of the anterior and middle fossa

Minimally invasive craniotomies are the subject of increasing attention over the last two decades in neurosurgery, following the current trend of attempting to increase patient safety by providing surgeries with less tissue disruption, blood loss, and decreased operative time. However, a significant information overlap exists among the various keyhole approaches regarding their indications and differences with more invasive techniques. Therefore, the present study aims to comprehensively review, illustrate, and describe the potential benefits and disadvantages of minimally invasive techniques to access the anterior and middle fossa, including the mini-pterional, mini orbito-zygomatic, supraorbital, lateral supraorbital, and extended lateral supraorbital approaches while comparing them to classic, more invasive approaches.

Mini-craniotomy for intra-axial brain tumors: a comparison with conventional craniotomy in 306 patients harboring non-dural based lesions

The use of a mini-craniotomy approach involving linear skin incision and a bone flap of about 3 cm has been reported for several neurosurgical diseases, such as aneurysms or cranial base tumors. More superficial lesions, including intra-axial tumors, may occasionally raise concerns due to insufficient control of the tumor boundaries. The convenience of a minimally invasive approach to intrinsic brain tumors was evaluated by comparing 161 patients who underwent mini-craniotomy (MC) for intra-axial brain tumors with a group of 145 patients operated on by the same surgical team through a conventional craniotomy (CC). Groups were propensity-matched for age, preoperative condition, size and location of the tumor, and pathological diagnosis. Results were analyzed focusing on operative time, the extent of resection, clinical outcome, hospitalization time, and time to start adjuvant therapy. Mini-craniotomy was equally effective in terms of extent of resection (GTR: 70.9% in the MC group vs 70.5% in the CC group) but had shorter operative time (average: 165 min in the MC group vs 205 min in the CC group p < 0.001) and lower rate of postoperative complications both superficial (1.03% vs 6.5% in the CC group p = 0.009) and deep (4% in the MC group vs 5.5% in the CC group p = 0,47). No relationship was found between the size or location of the tumor and resection rate. The MC group had reduced hospitalization time (average: 5.8 days vs 7.6 in CC group p < 0.001) and faster access to adjuvant therapies. 92.5% of the MC patients, which were scheduled for treatment, started radiotherapy within 8 weeks after surgery as opposed to 84.1% in the CC group (p = 0.04). These findings support the increasing use of mini-craniotomy for intra-axial brain tumors.

Supraorbital Keyhole Craniotomy in Pediatric Neurosurgery: A Systematic Review of Clinical Outcomes and Cosmetic Outcomes

BACKGROUND

Supraorbital keyhole craniotomy is a minimally invasive approach used to access the parasellar region with advantages of decreased cortical exposure, simple closure, and decreased risk of postoperative cerebrospinal fluid leak. The incision of this approach, however, has raised cosmetic concerns, especially for pediatric patients. The aim of this study is to assess postoperative complications and cosmeses of the supraorbital keyhole approach for resection of intracranial lesions in pediatric patients.

METHODS

A literature search of PubMed, Scopus, and Web of Science databases was performed on June 1, 2021, searching for all studies of pediatric patients undergoing supraorbital keyhole craniotomy for surgical resection of lesions in the anterior fossa/sellar region.

RESULTS

Of 729 unique hits, 15 supraorbital keyhole studies reporting on 177 pediatric cases were included in the final review. Quality of all included studies was moderate. Overall, the surgery was well tolerated with a low number of severe adverse events. A wide variety of pathologies were treated with this approach. Complications of surgery included changes in vision, epidural hematoma, subdural hematoma, cerebrospinal fluid leak, and wound infection. At 6 weeks of follow-up, surgical scars in most patients were noted to be minimally detectable. At 3-6 months of follow-up, scars were no longer visible. Cosmetic complications included 5 bone defects, 1 split eyebrow, and 1 case of ptosis.

CONCLUSIONS

This study suggests that supraorbital keyhole craniotomy is a safe and effective approach to access the parasellar region in pediatric patients with excellent cosmetic outcomes reported across multiple institutions.

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.

Tailored Skull Base Approach to Management of Intracranial Aneurysms

Surgical management of intracranial aneurysms (IAs) remains one of the most challenging and dynamic tasks for neurosurgeons. The rivalry between modern time microsurgery and progress in endovascular intervention has provided a great arena for advancement and lead to redefine training concept and referral pattern. Both approaches has its own merits, risks and complications and the best outcome is achieved by case individualization and complimentary multidisciplinary approach.The recent innovation in microscopic and endoscopic tailored skull base approaches, intraoperative 3D and ICG video-angiography, design of high quality aneurysm clips, and refinement of cerebral bypass techniques enhance IAs neurosurgical management and their clinical outcome. The command of tailored skull base approaches should be part of the training curriculum of young generation of neurosurgeons to compliment the emerging treatment options of endovascular intervention.

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.

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.

Supraorbital eyebrow keyhole approach for microsurgical management of ruptured anterior communicating artery aneurysm

The mortality and disability rate of patients with ruptured anterior communicating artery (AComA) aneurysm after bleeding is high. Even with the most advanced treatment methods, the incidence of complications remains high. The purpose of the present study was to determine the efficacy of microsurgery via supraorbital eyebrow keyhole approach (SOEK) in clipping ruptured AComA aneurysms. Between September 2010 and October 2018, 543 patients with intracranial aneurysms were admitted to the Department of Neurosurgery of the Third Affiliated Hospital of Sun Yat-Sen University (Guangzhou, China). Among them, 85 patients with ruptured AComA aneurysm and subarachnoid hemorrhage (SAH) underwent microsurgical clipping via the SOEK approach. In those patients, the clipping rate, complications and clinical efficacy of treatment were evaluated. The average age of the patients was 52.69±9.94 years (range, 28-78 years). The proportions of small, medium and large aneurysms were 83.5, 15.3 and 1.2%, respectively. Procedural complications occurred in 9 cases (10.5%). The occlusion rate of the aneurysms was 98.8%. The average follow-up period was 37.9 (±24.5) months. A total of 81.2% of the patients with SAH had a good clinical prognosisat 1 year (modified Rankin scale score, ≤2). In conclusion, for a skilled and experienced surgeon, SOEK was indicated to be a safe procedure for the treatment of ruptured AComA aneurysms; it provided sufficient intra-operative exposure and a high clipping rate.

Minipterional craniotomy for surgical clipping of anterior circulation aneurysms: compatibility between the feasibility, safety and efficiency

Objective

The aim of this study was to assess the feasibility, safety and efficiency of minipterional craniotomy (MPT) for surgical clipping of anterior circulation aneurysms.

Methods

A retrospective study was conducted to compare the MPT from Jan 2015 to Dec 2018 and conventional pterional craniotomy (CPT) from Jan 2012 to Dec 2013 in unruptured intracranial aneurysms (UIA) and ruptured intracranial aneurysms (RIA). The feasibility and safety of MPT and CPT were assessed by analyzing medical records, radiologic imaging, and clinical outcomes. The efficiency of MPT and CPT were based on a survey research of temporomandibular dysfunction, facial nerve paralysis, and facial asymmetry.

Results

Total 628 patients who underwent 458 MPT (UIA:313, RIA:145) and 170 CPT (UIA: 106, RIA: 64) with anterior circulation aneurysms were included in this study. The baseline characteristics between MPT and CPT had no difference (p>0.05). There was no difference in the incidence of postoperative hemorrhage or ischemic lesions between MPT and CPT (p>0.05). The incidence of surgical wound infection was lower in MPT (0.4%) than CPT (3.5%) (p=0.002). More than 90% of postoperative pain disappeared faster in MPT (14.25±4.83 days) than CPT (27.59±10.35 days), and the feeling of facial asymmetry in surgical side was also lower for MPT (1.7%) than CPT (7.6%) (p<0.001). In the MPT, no patients presented with progress to chronic pain, masticatory disability, discomfort of maximal mouth opening or permanent facial palsy.

Conclusions

We suggest that MPT and CPT had similar clinical outcomes, and MPT showed better functional and cosmetic outcomes than CPT in terms of temporomandibular dysfunction, facial nerve paralysis, and facial asymmetry. Therefore, MPT for surgical clipping of anterior circulation aneurysms can be a compatible technique that satisfies the feasibility, safety and efficiency.

Adverse intraoperative events during surgical repair of ruptured cerebral aneurysms: a systematic review

Compared with endovascular techniques, clipping of ruptured cerebral aneurysms has been shown to associate with increased morbidity in several studies. Despite this, clipping remains the preferred option for many aneurysms. The objective of this study is to describe the reported adverse events of open repair of ruptured cerebral aneurysms and their impact on patient outcome. The PubMed, Embase and Cochrane databases were searched between June 1999 and June 2019 to identify original studies of at least 100 patients undergoing surgical repair of ruptured cerebral aneurysms and in which adverse event rates were reported. Thirty-six studies reporting adverse events in a total of 12,410 operations for repair of ruptured cerebral aneurysms were included. Surgical adverse events were common with 36 event types reported including intraoperative rupture (median rate of 16.6%), arterial injury (median rate of 3.8%) and brain swelling (median rate 5.6%). Only 6 surgical events were statistically shown to associate with poor outcomes by any author and for intraoperative rupture (the most frequently analysed), there was an even split between authors finding a statistical association with poor outcome and those finding no association. Even with modern surgical techniques, the technical demands of surgical aneurysm repair continue to lead to a high rate of intraoperative adverse events. Despite this, it is not known which of these intraoperative events are the most important contributors to the poor outcomes often seen in these patients. More research directed towards identifying the events that most drive operative morbidity has the potential to improve outcomes for these patients.

[microsurgery 'burr hole' for intracranial tumors and mesial temporal lobe epilepsy]

PURPOSE

In recent years, neurosurgery has been characterized by a clear tendency towards the development of minimally invasive and less traumatic surgical approaches. To minimize the degree of injury to the brain tissue, we have proposed burr hole-based microsurgical approaches.

MATERIAL AND METHODS

In the period between February 2016 and February 2019, more than 500 microsurgical interventions were performed through a 14 mm burr hole using a technique that we called burr-hole microneurosurgery; to date, 200 of these have been analyzed. The age of patients varied from 16 to 79 years (median, 38 years). Female patients predominated - 1.6:1. Surgery for intracranial lesions with various locations was performed in 176 cases; in the remaining 24 cases, patients with hippocampal sclerosis underwent selective amygdalohippocampectomy.

RESULTS

Various surgical approaches were used: transcortical approach in 81 (40.5%) cases; retro-sigmoid approach in 38 (19%); sub-temporal approach in 32 (16%); infratentorial supracerebellar approach in 25 (12.5%); interhemispheric approach in 17 (8.5%); telovelar approach in 5 (2.5%); trans-eyebrow approach in 2 cases. The resection degree was evaluated in 167 patients with planned maximum tumor resection. Resection was total and almost total in 145 (87%) patients, subtotal in 15 (9%), and partial in 7 (4%). The surgery duration varied from 35 to 300 min (mean, 80 min). The extubation time after surgery ranged from 5 min to 5 days (mean, 70 min). In 195 (97.5%) cases, patients were verticalized within the first 3 days after surgery.

CONCLUSION

The proposed burr hole technique enables successful surgery in patients with various intracranial pathologies, using a smaller trepanation window compared to that in keyhole surgery. The proposed burr hole technique minimizes injury to the brain substance, significantly reduces patient's exposure to anesthesia, and decreases the entire duration of surgery.

Transpalpebral Approach for Microsurgical Removal of Tuberculum Sellae Meningiomas

BACKGROUND

The evolution of skull base approaches associated with individualization of surgical corridor and minimizing the collateral damage. Achieving the radical removal of tumor and preserving the neurological status of the patient is possible, both with the traditional approaches and keyhole approaches. Our work presents experience using the transpalpebral approach (TPA) for microsurgical removal of tuberculum sellae meningioma (TSM).

MATERIALS AND METHODS

A total of 15 patients with meningiomas underwent microsurgical removal of TSM through TPA. Ten patients were women and five were men. The standard preoperative diagnostic protocol includes magnetic resonance imaging with contrast enhancement, brain computed tomography for neuronavigation. We assess surgical complications, functional and cosmetic outcomes, and surgical parameters, including the time of surgery and intraoperative blood loss.

RESULTS

Visual impairment was finding in 100% patients, including slight decrease of vision (46,7%, seven patients), partial vision field loss (six patients, 40%), and serious visual impairment (two patients 13.3%). Visual improvement was noted in ten cases (66.7%), there was no improvement in four cases (26.7%), and one case (6.6%) had transient visual worsening for 4 days and slow improvement in 1 month. Headache disappeared in three patients (50%). There were no cases of cerebrospinal fluid leak. Transient frontal hypoesthesia was noted in all patients (100%) without permanent deficit. Transient palsy of the frontal muscle was noted in four patients for 4-6 months. Histological examination revealed WHO Grade I meningioma in 14 cases and in 1 case WHO Grade II meningioma. No deaths were identified in follow-up at 12 months. The average value of the Modified Rankin Scale was 1.4. The mean length of stay in hospital was 5.

CONCLUSION

TPA is technically difficult and requires some experience to work in deep structures in a small surgical corridor. This technique can be good alternative to traditional fronto-lateral, supraorbital keyhole craniotomies, and endoscopic endonasal approaches.

Facial Nerve Preservation for Supraorbital Approaches: Anatomical Mapping Based on Consistent Landmarks

BACKGROUND

The supraorbital keyhole approach (SOKA) provides a safe and advantageous access to the anterior cranial fossa. The implemented skin incision varies depending on surgeon's preferences and requirements. Facial nerve (FN) injury might appear in up to 5.6% of patients. There is a lack of validated tenets for avoiding FN injury.

OBJECTIVE

To define a safety area for FN preservation during a SOKA.

METHODS

Ten dried skulls and 5 injected cadaveric heads (10 sides) were used. A Cartesian frame was created with its horizontal axis at the level of the supraorbital notch and the vertical axis just lateral to the frontozygomatic junction (FZj). FNs were dissected and points along their course were registered and transferred to the Cartesian frame.

RESULTS

Ten microscopic dissections of the FN were performed preserving all branches. A safety area could be defined 8 mm superior and 10 mm inferior to the FZj extending medially to the supraorbital notch and beyond. A 20 mm2 area superior and lateral to the FZj provided low probability (≤10%) of injuring the FN. Similarly, starting 4 mm inferior to the FZj, a lateral safety area was also found. A probabilistic colored heat map was built to represent the results.

CONCLUSION

We provide a "safety zone" for a SOKA incision in which the probability to encounter the FN is low. Clinical studies following our method may validate our findings and add evidence to the tenets for minimizing morbidity related to the SOKA incision.

[Operative skull base approaches]

CLINICAL ISSUE

Knowledge of skull base anatomy is essential for recognizing the pathological conditions affecting the skull base structures (including cranial nerves and cerebral vasculature), for correct interpretation of their presentation on imaging studies, and finally for proper planning of surgical skull base approaches.

PURPOSE OF THE ARTICLE

The main goal of the following work is to present a brief recapitulation of the regular skull base anatomy (with a focus on the bony structures) and based on this, to provide an overview of the most commonly used neurosurgical skull base approaches (illustrated using radiological case presentations).

DIAGNOSTIC WORK-UP

Already at the step of the preoperative workup, the suitable radiological technique and proper choice of technical parameters for image acquisition lays the foundation for a successful surgical procedure and for the reliable assessment of operative results.

CONCLUSION

Each radiologist should be familiar with basic principles of neurosurgical approaches and operative techniques used in skull base surgery and with their appearance in postoperative images.

Supraorbital keyhole approach: Pure endoscopic and endoscope-assisted perspective

OBJECTIVE

To assess the assumed advantages of pure endoscopic and endoscope-assisted methods for the supraorbital keyhole approach. The aim is to demonstrate visibility and accessibility of the pure endoscope approach as a possible standard approach for the supraorbital keyhole approach.

PATIENTS AND METHODS

We performed eight dissections on four cadaver heads using an operating microscope, an endoscope, and neuronavigation. The visibility and accessibility of the anterior and middle cranial fossae regions were compared for each. Special structures were defined to assess their preservation in both approaches. We used pure endoscopy on the eight sides and with a microscope on those same eight sides. Accessibility was quantified for key structures using linear measurements taken with the navigation system. In addition, we present clinical cases in which an endoscope-assisted supraorbital approach was employed.

RESULTS

Our measurements have been reported for each side in the formalin-fixed heads as the mean ± SD (in mm) from the bone margin to selected regions. Moreover, image analysis was performed using ImageJ software to compare selected surface area measurements between the endoscope and microscope images on each side for all cadaveric available specimens. There were no significant statistical differences between visualization of the selected areas. This means that by visual analysis both endoscopic and microscopic images can provide the surgeon nearly the same visibility and accessibility of a selected region.

CONCLUSION

A pure endoscopic method can be used to conduct the supraorbital keyhole approach when the endoscope is used as a primary tool. Our recommendation is to use the measurements described in this study for preoperative planning of the keyhole approach. We believe that with advances in neuro-endoscope technology, and instrumentations, the endoscopic approach may replace the microscopic approach in the near future.

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.

[A comparative study of the efficacy and safety of the eyebrow supraorbital approach in cerebral aneurysm surgery]

OBJECTIVE

The study objective was to compare the efficacy and safety of supraorbital eyebrow (SEA) and pterional (PA) approaches in surgery of anterior circle of Willis (ACW) aneurysms and to determine the advantages and disadvantages of SEA in aneurysm clipping.

MATERIAL AND METHODS

The analysis included 166 patients with ACW aneurysms aged 18 to 70 years who were treated in the Neurosurgery Department of the Interregional Clinical Diagnostic Center (Kazan) in the period from 2013 to 2016. At the first stage of the study, factors affecting surgical outcomes were compared (by using the Glasgow outcome scale (GOS)) in subpopulations of patients operated on using SEA (n=49) and PA (n=117). At the second stage, we compared the efficacy and safety of approaches using a case-control subanalysis in appropriate subgroups of the SEA (n=37) and PA (n=37) groups. The subgroups were comparable in the following factors: gender, age, severity of subarachnoid hemorrhage (SAH) on (Fisher scale), severity of the patient's condition (Hunt-Hess scale), size and location of the aneurysm, surgery duration, intraoperative aneurysm rupture (IOAR), amount of blood loss, rate of frontal sinus surgery, rate of nasal CSF leak, rate of intraoperative and postoperative complications, hemorrhagic and ischemic complications according to postoperative CT, patient's satisfaction with the cosmetic result of surgery (visual analogue scale - VAS), and treatment outcomes (GOS). Treatment outcomes (GOS) and patient's satisfaction with the cosmetic result of surgery (VAS) were considered as the efficacy parameters. The safety parameters included the amount of blood loss, rate of frontal sinus surgery, rate of nasal CSF leak, and rate of intraoperative and postoperative (hemorrhagic and ischemic) complications.

RESULTS

At the first stage of the study, we found that the amount of intraoperative blood loss in the subpopulation of patients with ACW aneurysms who were operated on using SEA was statistically significantly less than that in the PA group (p=0.0000002). In the postoperative period, patients who underwent surgery using SEA less frequently experienced neurological deficit (p=0.003), less frequently developed first epileptic seizures (p=0.035), and had a lower rate of hemorrhagic complications (p=0.003) and better treatment outcomes (GOS) (p=0.01). Comparison of appropriate subgroups in the SEA and PA groups, which were selected according to the case-control methodology and were comparable in the main factors affecting treatment outcomes, confirmed statistically significantly lower blood loss for SEA (p=0.0000002) than for PA. Compared to the SEA group, the PA group was characterized by more frequent, but not statistically significantly different, IOAR (p=1), postoperative worsening of neurological deficit (p=0.115), newly developed epileptic seizures (p=0.493), and hemorrhagic complications (p=0.0557). There were no deaths in both groups. In the SEA group, the treatment outcome was scored 4 and 5 (GOS, favorable outcome); in the PA group, the treatment outcome was scored 3 (GOS) in 2 (5.4%) patients and 4 or 5 in 35 (94.6%) patients (p=0.063). The mean subjective score of satisfaction with the treatment result (VAS) in the SEA group was significantly higher (9.4±1) than in the PA group (8.8±1; p=0.01).

CONCLUSION

SEA is an adequate approach for clipping ACW aneurysms, in particular ACA-AComA and MCA aneurysms, which is as effective and safe as the pterional approach.

Extended Lateral Orbital Craniotomy: Anatomic Study and Initial Clinical Series of a Novel Minimally Invasive Pterional Approach

Background  Of the minimally invasive "keyhole" alternatives to the pterional region, the supraorbital eyebrow approach is the most widely adopted. Yet it can prove disadvantageous when a more direct lateral microsurgical trajectory of attack to the Sylvian fissure and anterior middle fossa are needed. Objective  The extended lateral orbital (XLO) approach was designed to be direct and minimally invasive, with the sphenoid ridge at the center of exposure. Methods  Five injected cadaver heads were used for anatomic study of the XLO approach. The anatomic course of the frontalis branch of facial nerve was studied in relation to the XLO incision. Following XLO incision, the bone exposure was measured. The intracranial microsurgical exposure was assessed subjectively. Application of the technique in representative clinical operative cases is provided. Results  The frontalis nerve was protected in the subgaleal fat pad, with an average minimum distance of 2.3 cm from the XLO incision. The mean calvarial area exposure was 4.95 cm ² and consistently centered on the sphenoid ridge. Excellent access to ipsilateral Sylvian's fissure, perisylvian regions, and supra-/parasellar structures was possible. The main limitations related to exposure of the posterior Sylvian fissure and the expected limitations of microsurgical instrument manipulation from a smaller craniotomy. Conclusions  The XLO approach is a minimally invasive keyhole approach to the pterional region that affords a unique lateral trajectory via a craniotomy centered on the sphenoid ridge. Excellent exposure to properly selected lesions is possible. The incision is at a safe distance from the frontalis branch and shows excellent cosmetic healing.

Comparative Analysis of the Exposure and Surgical Freedom of the Endoscopic Extended Minipterional Craniotomy and the Transorbital Endoscopic Approach to the Anterior and Middle Cranial Fossae

BACKGROUND

Numerous minimally invasive approaches to the skull base have been successively developed. Knowledge of the surgical nuances of a specific approach may facilitate approach selection. This study sought to compare the nuances of an extended version of the minipterional craniotomy (EMPT) with those of the transorbital endoscopic approach (TOEA) to the anterior and middle cranial fossae (ACF and MCF, respectively).

OBJECTIVE

To quantitatively analyze and compare the area of exposure and surgical freedom between EMPT and TOEA to the ACF and MCF.

METHODS

EMPT and TOEA were carried out in 5 latex-injected cadaveric heads, bilaterally (10 sides). For each approach, the area of exposure, surgical freedom, and angle of attack were obtained with neuronavigation and statistically compared.

RESULTS

No significant difference was found between the mean area of exposure of EMPT and TOEA at the ACF and MCF (P = .709 and .317, respectively). The mean exposure area at the ACF was of 13.4 ± 2.6 cm2 (mean ± standard deviation) and 13.0 ± 1.9 cm2 for EMPT and TOEA, respectively. Except for the crista galli, EMPT afforded a larger area of surgical freedom at all targets. EMPT also achieved significantly greater attack angles in vertical axis except to the crista galli. The horizontal attack angles to all targets were similar between approaches.

CONCLUSION

EMPT and TOEA offer a comparable area of exposure at the ACF and MCF in the cadaver; however, the instrument maneuverability afforded by EMPT is superior. Further studies are necessary to better define their precise surgical application.

A literature review concerning contralateral approaches to paraclinoid internal carotid artery aneurysms

Ipsilateral approaches remain the standard technique for clipping paraclinoid aneurysms. Surgeons must however be prepared to deal with bony and neural structures restricting accessibility. The application of a contralateral approach has been proposed claiming that some structures in the region can be better exposed from this side. Yet, only few case series have been published evaluating this approach, and there is a lack of systematic reviews assessing its specific advantages and disadvantages. We performed a structured literature search and identified 19 relevant publications summarizing 138 paraclinoid aneurysms operated via a contralateral approach. Patient's age ranged from 19 to 79 years. Aneurysm size mainly varied between 2 and 10 mm and only three articles reported larger aneurysms. Most aneurysms were located at the origin of the ophthalmic artery, followed by the superior hypophyseal artery and carotid cave. All aneurysm protruded from the medial aspect of the carotid artery. Interestingly, minimal or even no optic nerve mobilization was required during exposure from the contralateral side. Strategies to achieve proximal control of the carotid artery were balloon occlusion and clinoid segment or cervical carotid exposure. Successful aneurysm occlusion was achieved in 135 cases, while 3 ophthalmic aneurysms had to be wrapped only. Complications including visual deterioration, CSF fistula, wound infection, vasospasm, artery dissection, infarction, and anosmia occurred in a low percentage of cases. We conclude that a contralateral approach can be effective and should be considered for clipping carefully selected cases of unruptured aneurysms arising from medial aspects of the above listed vessels.

Supraorbital keyhole versus pterional craniotomies for ruptured anterior communicating artery aneurysms: a propensity score-matched analysis

The safety and efficacy of the supraorbital keyhole approach for aneurysm surgery have not been well researched through a high-quality controlled study. The objective of the study was to compare the safety and efficacy of the supraorbital and pterional approaches for ruptured anterior communicating aneurysm (AComAn). A total of 140 patients, with 70 patients in each group, were enrolled after 1:1 propensity score matching. Clinical variables, postoperative complications, and long-term outcomes were retrospectively compared. Baseline characteristics were equivalent between the two groups. Significantly shorter operative time and less intraoperative blood loss were observed in the supraorbital group compared to the pterional group (141.9 min vs. 184.5 min, P < 0.001; 160.4 ml vs. 250.7 ml, P = 0.008). The incidence of intraoperative aneurysm rupture was similar between the groups (20% vs. 18.6%, P = 0.830). The rate of procedural complications involving subdural hematoma and intracranial infection was lower in patients treated through the supraorbital (10.0%) vs. the pterional approach (32.9%, P < 0.001), but no significant difference was observed for the incidence of ischemic events (15.7% vs. 18.6%, P = 0.654). Within a median 33.4-month (range, 11-67 months) follow-up, a similar proportion of patients achieved a favorable outcome (Glasgow Outcome Scale IV or V) across the two groups (83.6% vs. 80.0%, P = 0.285), while better cosmetic results were observed in the supraorbital group (94.0%) vs. the pterional group (86.2%, P = 0.129). According to our results, we recommend the keyhole approach for AComAn surgery for neurosurgeons who have gained sufficient experience with this technique due to its advantages over the pterional approach.

[The trans-eyebrow supraorbital approach for removal of anterior cranial fossa and suprasellar meningiomas]

Over the past two decades, improvements in surgical tools, navigation systems, and endoscopic techniques have resulted in the widespread use of keyhole surgery for a wide range of skull base tumors. Currently, the trans-eyebrow supraorbital approach is being increasingly used in surgery for anterior cranial fossa and parasellar tumors.

MATERIAL AND METHODS

The study included 7 patients who underwent surgery for meningioma using the trans-eyebrow supraorbital approach at the Burdenko Neurosurgical Institute in the period between 2013 and 2017. The age of patients ranged from 51 to 75 years (median, 60 years); there were 5 females and 2 males. The maximum diameter of resected tumors ranged from 20 to 60 mm (median 40 mm).

RESULTS

Total resection of the tumor was achieved in all 7 cases, which was confirmed by postoperative MRI control. All 7 patients had a good cosmetic result. In 1 case, there was postoperative cerebrospinal fluid rhinorrhea due to incomplete closure of the frontal sinus, which required the patient to be re-operated. None of 7 cases was associated with injury to the main vessels or cavernous sinus.

CONCLUSION

Supraorbital trans-eyebrow craniotomy provides a minimally invasive approach for removing most anterior cranial fossa base and suprasellar tumors. The advantages of keyhole surgery, in comparison with traditional craniotomies, are minimal complications associated with the approach.

Postoperative Imaging Findings Associated with Transpalpebral Craniotomy Approach to Anterior Cranial Fossa

Background and Purpose  The transpalpebral "eyelid" approach is a novel alternative to the traditional ciliary or supraciliary incision for supraorbital frontal craniotomy and access to the anterior cranial fossa. Though a prior publication from our institution has described the surgical approach in detail along with cosmetic and clinical outcomes, postoperative imaging findings have not yet been described. As this surgical technique becomes more widely practiced, it is essential for neuroradiologists, oculoplastic surgeons, and skull base neurosurgeons to be familiar with the expected postoperative imaging findings, especially those that prompt subsequent intervention. Materials and Methods  A retrospective, institutional review board approved review was performed of 102 patients who underwent transpalpebral surgical approach at Allegheny General Hospital from June 2007 through May 2015. Operative reports, pathology reports, preoperative imaging, postoperative imaging, and postoperative clinical documentation were reviewed. Results  Forty-nine percent of patients had solely benign expected postoperative imaging findings, 37% had various atypical findings not requiring further intervention (most commonly asymmetric globe protrusion and bone cement in a paranasal sinus), 6% had findings prompting minimally invasive bedside procedures (most commonly pseudomeningocele), and 8% had findings requiring surgical intervention. Conclusion  The majority of imaging following the transpalpebral approach showed typical, benign findings, such as minimal pneumocephalus and asymmetric globe protrusion. Nonetheless, members of the clinical team should be aware of the small number of findings requiring intervention, especially pseudomeningocele.

Preservation of hormonal function by identifying pituitary gland at endoscopic surgery

OBJECTIVE

The endonasal endoscopic approach has been established for perisellar tumor surgery with a higher resection rate and reduced complications. We analyzed the potential to identify the pituitary gland under endoscopic view, at surgery and see its relation to postoperative hormonal insufficiency in endonasal endoscopic procedures.

METHODS

Between January 2011 and January 2014, 70 cases of pituitary adenomas with preoperative intact pituitary function underwent endoscopic endonasal transsphenoidal procedures for intrasellar pathologies. Endocrinologists and neurosurgeons followed these patients prospectively. Special attention was paid to intraoperative identification of gland tissue, surgical complications, degree of resection and postoperative hormonal insufficiency.

RESULTS

The pituitary gland was identified in 57 out of 70 procedures (81.4%). Eleven percent (8 of 70 patients) had persistent pituitary insufficiency. Two of these 8 patients belonged to the group with pituitary gland identification (2 out of 57); thus, when the pituitary gland was identified during the procedure postoperative hormonal insufficiency was seen in 3.5% of cases. Failure of pituitary gland identification presented with hormonal insufficiency of 46.2%. In analysis with Fisher's exact test, there was a high significant correlation between the identification of the pituitary gland intraoperatively and normal pituitary function postoperatively (p<0.005). On follow up radical tumor resection was seen in 88% (62 of 70 patients).

CONCLUSIONS

This study indicates that identification and preservation of pituitary gland tissue and function is possible in endoscopic transsphenoidal surgery. This preservation of gland tissue is a positive predictor of postoperative normal pituitary function.

Frontal Keyhole Craniotomy for Resection of Low- and High-Grade Gliomas

BACKGROUND

Minimally invasive techniques are increasingly being used to access intra-axial brain lesions.

OBJECTIVE

To describe a method of resecting frontal gliomas through a keyhole craniotomy and share the results with these techniques.

METHODS

We performed a retrospective review of data obtained on all patients undergoing resection of frontal gliomas by the senior author between 2012 and 2015. We describe our technique for resecting dominant and nondominant gliomas utilizing both awake and asleep keyhole craniotomy techniques.

RESULTS

After excluding 1 patient who received a biopsy only, 48 patients were included in the study. Twenty-nine patients (60%) had not received prior surgery. Twenty-six patients (54%) were diagnosed with WHO grade II/III tumors, and 22 patients (46%) were diagnosed with glioblastoma. Twenty-five cases (52%) were performed awake. At least 90% of the tumor was resected in 35 cases (73%). Three of 43 patients with clinical follow-up experienced permanent deficits.

CONCLUSION

We provide our experience in using keyhole craniotomies for resecting frontal gliomas. Our data demonstrate the feasibility of using minimally invasive techniques to safely and aggressively treat these tumors.

[Minipterional craniotomy in surgery for anterior circle of Willis aneurysms]

One of the significant events in aneurysm surgery was promotion of a microneurosurgical technique by G. Yasargil. Despite its versatility, pterional craniotomy is associated with extensive osteotomy and a significant incision of the skin and temporal muscle, which may lead to the adverse cosmetic effects, risk of temporomandibular joint dysfunction, injury to the frontal branch of the facial nerve, and facial and scalp numbness. We present our experience with minipterional craniotomy in surgery for anterior circle of Willis aneurysms in 40 patients. There were no serious complications or deaths. Also, there were no intraoperative aneurysm ruptures. All patients had expected transient hypesthesia in the temporal region, which was not considered as a complication. This region was significantly smaller compared to that in classical pterional craniotomy. Patients assessed the postoperative cosmetic outcome as excellent.

Cooling Activity is Associated with Neurological Outcome in Patients with Severe Cerebrovascular Disease Undergoing Endovascular Temperature Control

BACKGROUND

Neuroprotection through targeted temperature management is currently investigated in patients with severe brain injury in multiple trials. Feedback devices have been shown to precisely reach and maintain target temperature by constantly adjusting cooling activity. We analyzed the association between cooling activity expressed as cool bath temperatures and functional neurological outcome.

METHODS

Data were retrospectively analyzed from a prospective randomized trial on controlled prophylactic normothermia (i.e., 36.5 °C) in patients with severe cerebrovascular disease. Body core temperature of patients who had been randomized to the endovascular group, was controlled using an endovascular cooling device. Cool bath temperature was analyzed over a period of 168 h. Functional neurological outcome was evaluated at 180 days using the modified Rankin Scale.

RESULTS

51 of 102 patients included were randomized to the endovascular group. Cool bath temperature data were available from 47/51 patients. Patients with lower cool bath temperatures reflecting high cooling activity had a more favorable neurological outcome at 180 days (mRS 0-2) than patients with low cooling activity (p < 0.05). We did not find a significant correlation between cool bath temperature and inflammatory markers.

CONCLUSION

High cooling activity of an endovascular feedback device is associated with favorable outcome in patients with severe cerebrovascular disease.

Intraoperative Combined Use of Somatosensory Evoked Potential, Microvascular Doppler Sonography, and Indocyanine Green Angiography in Clipping of Intracranial Aneurysm

Background

The aim of this study was to evaluate the effect of combining application of somatosensory evoked potential (SEP), microvascular Doppler sonography (MDS), and indocyanine green angiography (ICGA) in intracranial aneurysm clipping surgery.

Material/Methods

A total of 158 patients undergoing an intracranial aneurysm clipping operation were recruited. All patients were evaluated with intraoperative SEP and MDS monitoring, and 28 of them were evaluated with intraoperative combined monitoring of SEP, MDS, and ICGA.

Results

The SEP waves dropped during temporary occlusion of arteries in 19 cases (12.0%), and returned to normal after the clips were repositioned. After aneurysms were clipped, the vortex flow signals were detected by MDS in 6 cases. The aneurysm neck remnants were detected by ICGA in 2 cases of olfactory artery (OA) and in 1 case of middle cerebral artery (MCA), which disappeared after the clips were repositioned. Postoperative CTA or DSA showed that aneurysms were clipped completely and parent arteries and perforating vessels were patent. GOS at 1 month after the surgery was good in 111 cases (70.3%), mild disability in 22 cases (13.9%), severe disability in 14 cases (8.9%), vegetative state in 5 cases (3.2%), and death in 6 cases (3.8%).

Conclusions

Intraoperative combining application of SEP, MDS, and ICGA can reduce brain tissue ischemia and damage and disability and mortality rate after effective clipping of intracranial aneurysms, thereby improving surgical outcomes.

Safety, efficacy, and cost of surgery for patients with unruptured aneurysms deemed unsuitable for endovascular therapy

BACKGROUND

Open surgery is a frequent option given to patients with unruptured intracranial aneurysms (UIAs) unsuitable for endovascular repair. Since the risk of rupture of UIAs is generally low, we determined whether the risks and costs of surgery in this patient subset are warranted.

METHODS

The safety, efficacy, and costs of minimally invasive surgery by minicraniotomy were evaluated in 102 consecutive patients with anterior circulation UIAs deemed unsuitable for endovascular repair by an interdisciplinary conference of surgeons and neurointerventionalists. Data from 107 UIA patients treated by endovascular means in the same period were used as the standard.

RESULTS

Surgical patients comprised a different subset of aneurysms, with more MCA and fewer paraophthalmic aneurysms (54 vs. 6, p < 0.0001 and 4 vs. 60, p < 0.0001, for minicraniotomy and endovascular, respectively). However, surgery incurred shorter anesthesia time (197.7 vs. 149.3 min, p < 0.0001), higher rates of complete aneurysm obliteration (94.57 vs. 66.67 %, p < 0.0001), and lower overall hospital costs ($8,287 CAD vs. $17,732 CAD, p < 0.0001) than the endovascular cohort. There were no treatment-related surgical deaths, but one patient had an mRS of 3 after 6 months due to temporal lobe epilepsy and memory problems. This compared favorably with the endovascular cohort in which two patients died due to treatment (mRS = 6) and one suffered a severe stroke (mRS = 5 at 6 months).

CONCLUSIONS

For patients counseled to undergo treatment but have UIAs unsuitable for endovascular repair, surgery is safe, effective, and cost-efficient.

Microsurgical Treatment of Posterior Cerebral Circulation Aneurysms Via Keyhole Approaches

OBJECTIVE

To explore the techniques of microsurgical treatment for posterior cerebral circulation aneurysms via keyhole approaches and assess its feasibility.

METHODS

A total of 27 patients with 28 posterior cerebral circulation aneurysms were treated surgically by keyhole approaches; 24 patients presented with subarachnoid hemorrhage and 3 with headache. Of these 27 patients, 15 patients were treated via the supraorbital keyhole approach, 6 via the retrosigmoid keyhole approach, 3 via the subtemporal keyhole approach, 2 via median suboccipital approach, and 1 via the pterional keyhole approach.

RESULTS

Of the 28 posterior cerebral circulation aneurysms, 24 aneurysms were clipped and 4 trapped; 23 aneurysms clipped completely, and 1 had residual aneurysm. Glasgow Outcome Scores at discharge revealed 25 patients had a good recovery; 1 patient was slightly disabled, and 1 patient was severely disabled. Of 15 patients treated via the supraorbital keyhole approach, to make a wider operative space, drilling of anterior clinoid process (2 patients) and posterior clinoid process (3 patients) was performed; posterior communicating artery was cut off (1 patient). For 3 patients with multiple aneurysms, complete occlusion was achieved via the same approach at one-stage.

CONCLUSIONS

Individualized keyhole approaches for posterior cerebral circulation artery aneurysms are safe and effective. The anterior clinoid process or posterior clinoid process could be drilled to offer a wide operative space for clipping. The use of multiple working windows is very helpful for controlling the parent artery and clipping the aneurysm.

Mononostril endoscopic transsphenoidal approach to sellar and peri-sellar lesions: Personal experience and literature review

OBJECTIVE

The endonasal endoscopic approach to skull base is still under investigation. The main goal is the minimal invasive approach to pathologies with a better rate of resection without retraction of the brain tissue. Here, the authors report their technique of transnasal endoscopic neurosurgery using a mononostril approach and its development.

METHODS

The supplementary video demonstrates the different steps of the mononostril approach and resection of a pituitary adenoma. All video-recorded procedures that were carried out between 2000 and 2013 using this technique were analysed. The patients were followed prospectively.

RESULTS

Visualization and handling were good in 246/251 (98%). In three cases, we had to switch to microscopy because of severe bleeding of the cavernous sinus. On follow-up, magnetic resonance imaging revealed radical tumour resection in 92% of all cases when intended. There was no mortality, and the low complication rate was remarkable.

CONCLUSION

Our mononostril approach of transnasal transsphenoidal surgery shows better results compared with previously published reports in regards to radicality, low cerebrospinal fluid leaks and morbidity. The very low rate of nasal complains is particularly remarkable.

Keyhole concept in cerebral aneurysm clipping and tumor removal by the supraciliary lateral supraorbital approach

The keyhole concept in neurosurgery is designed to minimize the craniotomy needed for the access route to deep intracranial pathologies. Such keyhole surgeries cause less trauma and can be less invasive than conventional surgical techniques. Among the various types of keyhole mini-craniotomy, supraorbital or lateral supraorbital mini-craniotomy is the standard and basic keyhole approaches. The lateral supraorbital keyhole provides adequate working space in the suprasellar to parasellar areas and planum sphenoidale area including the anterior communicating artery complex. Despite the development of neuro-endoscopic techniques and intra-operative assistant methods, the limited working angle to manipulate and observe deeply situated pathologies is a major disadvantage of the keyhole approaches. Neurosurgeons should understand that keyhole mini-craniotomy surgeries aim at “minimally invasive neurosurgery” but still carry the risks of malpractice unless we understand the advantages and disadvantages of these keyhole concepts and strategies.

A safety, length of stay, and cost analysis of minimally invasive microsurgery for anterior circulation aneurysms

OBJECTIVES

The aim of our study was to evaluate minimally invasive techniques for the treatment of anterior circulation aneurysms versus standard surgery, and to calculate the impact of these techniques on health resources, length of stay, and treatment costs.

METHODS

A consecutive series of 24 patients with ruptured and 30 with unruptured anterior circulation aneurysms treated with minimally invasive microsurgery (MIM) by the same surgeon was compared with a matched series of standard microsurgeries (SM) conducted for 23 ruptured and 22 unruptured aneurysms. Complication rates, aneurysm obliteration, modified Rankin Scale (mRS) outcomes, length of stay, and treatment costs were assessed.

RESULTS

Surgical complications, aneurysm obliteration rates and mRS outcomes were comparable between MIM and SM groups in ruptured and unruptured aneurysm cohorts. MIM resulted in shorter operative times both in unruptured (102.7 ± 4.35 vs 194.7 ± 10.26 min, p < 0.0001) and ruptured aneurysms (124.3 ± 827 vs 209 ± 13.84 min, p < 0.0001). Length of stay was reduced in patients with MIM for unruptured aneurysms (1.55 ± 24 vs 4.28 ± 0.71 days, p < 0.000,1) but not in those with ruptured aneurysms. MIM reduced treatment costs of unruptured aneurysm patients, mainly through reduced utilization of inpatient resources (non-acute bed costs in CAD: 371.2 ± 80.99 vs 1440 ± 224.1, p < 0.0001), whereas costs were comparable in patients with ruptured aneurysms.

CONCLUSION

Minimally invasive surgery is a safe and effective approach for the treatment of ruptured and unruptured aneurysms of the anterior circulation. In patients with unruptured aneurysms, reduced invasiveness and shorter operative times decreased length of stay, which reflects improved patient postoperative recovery. Overall, this translated into bed resource economy and cost reduction.

The Supraorbital Keyhole Craniotomy through an Eyebrow Incision: Its Origins and Evolution

In the modern era of neurosurgery, the use of the operative microscope, rigid rod-lens endoscope, and neuronavigation has helped to overcome some of the previous limitations of surgery due to poor lighting and anatomic localization available to the surgeon. Over the last thirty years, the supraorbital craniotomy and subfrontal approach through an eyebrow incision have been developed and refined to play a legitimate role in the armamentarium of the modern skull base neurosurgeon. With careful patient selection, the supraorbital "keyhole" approach offers a less invasive but still efficacious approach to a number of lesions along the subfrontal corridor. Well over 1000 cases have been reported in the literature utilizing this approach establishing its safety and efficacy. This paper discusses the nuances of this approach, including the benefits and limitations of its use described through our technique, review of the literature, and case illustration.

Endoscopic endonasal transsphenoidal approach to sellar lesions: a detailed account of our mononostril technique

Objective The endonasal endoscopic approach is currently under investigation for perisellar tumor surgery. A higher resection rate is to be expected and nasal complications should be minimized. Here, the authors report their technique of transnasal endoscopic neurosurgery after 218 procedures. Methods Between October 2000 and September 2011, 210 patients received 218 endoscopic endonasal transsphenoidal procedures for perisellar lesions. Procedures were video recorded. The surgical technique was carefully analyzed. These cases were prospectively followed. Results Standard technique was mononostril approach with 0-degree optics. 30-degree and-after availability-45-degree optics were used for assessment of radicality. On follow-up, magnetic resonance imaging revealed radical tumor resection in 94 out of 104 cases (90.3%). Recurrent tumor growth was observed in five younger patients (2.2%). There was no mortality and a low complication rate. Three patients (1.4%) complained postoperatively of nasal congestion or reduced nasal air flow; however, no complaints were considered to be severe. Conclusion In comparison with other literature reports, the results are comparable or even better with respect to surgical radicality. The very low rate of nasal complaints is particularly remarkable. The technique has been shown to be safe and successful with a high radicality and only minor complications.

A cadaveric study of the endoscopic endonasal transclival approach to the basilar artery

The anterior transclival route to basilar artery aneurysms is not widely performed. The objective of this study was to carry out a feasibility assessment of the transclival approach to basilar aneurysms with advanced endonasal techniques on 11 cadaver heads. Clival dura was exposed from the sella to the foramen magnum between the paraclival segments of the internal carotid arteries (ICA) laterally. An inverted dural "U" flap was reflected inferiorly to expose the basilar artery. The maximal dimensions from operative measurements were recorded. Surgical manoeuvrability of multiple instruments and the proficiency to place proximal and distal vascular clips were evaluated. The mean operative depth (± standard deviation), measured from the anterior choanae to the basilar artery, was 110±6mm. The lateral corridors were limited distally by the medial pterygoids (mean width 21±2mm) and paraclival ICA (mean width 20±2mm). The mean transclival craniectomy dimensions were 19±2mm (width) and 23±4mm (height). Exposure of the basilar-anterior inferior cerebellar artery junction, superior cerebellar artery, and the basilar caput were possible in 100%, 91%, and 64% of instances, respectively. Placements of proximal and distal aneurysm clips were achieved in all instances. Based on our findings, the transclival endoscopic endonasal surgery approach provides excellent visualisation of the basilar artery. Clip application and manoeuvrability of instruments was considered adequate for basilar aneurysm surgery. Surgical skills and instrumentation to control significant haemorrhage can potentially limit the clinical applicability of this technique.