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The navigation of transcranial magnetic stimulation.

Transcranial magnetic stimulation (TMS) is a new method for investigating cortical information processing and for investigating therapeutic applications in psychiatry and neurology. A common problem of most studies in this field regards the localization of the magnetic coil with respect to the cortex. This article reviews the currently used methods and proposes a neuronavigational approach. The method of neuronavigated TMS is described and discussed in detail. It is used to guide the magnetic coil on an individual basis to a structurally or functionally predetermined cortical area while monitoring the location of the coil in relation to the subject's head in real time. Possible applications of TMS in combination with functional neuroimaging in clinical research within a cognitive neuroscience framework are discussed. Future applications of TMS should take individual anatomy into account, and neuronavigation provides the means to do so.

Brain Mapping↗

Incorrect vector after calibration of surgical instruments for image guidance. The problem and the solution: technical note.

Recently, the use of intra-operative image guidance has gained an increasing role in neurosurgery for both spinal and cerebral interventions. Some modern neuronavigation systems are able to register any surgical instrument and create a virtual pointer. A virtual elongation of the digitized instrument is frequently used for neuroendoscopic procedures and spinal instrumentation. The instrument is equipped with a universal instrument adapter clamp and digitized by touching the tip of the instrument into a calibration cone. An algorithm calculates the vector of the instrument using two points: the tip of the instrument, and the geometrical center of the instrument adapter geometry. If a virtual elongation of the calibrated instrument is performed, the neuronavigation software may calculate an incorrect virtual target point. We developed an instrument calibration matrix (ICM) that automatically calibrates the correct vector, tip, and diameter of the instrument used for image-guided surgery. The ICM is easy to handle and does not cause a time delay during surgery. Virtual elongation of the surgical instruments shows correct anatomic data, which are fundamental for planning ventricular tapping and spinal screw placement in particular. The instrument calibration matrix is essential if surgical instruments are digitized and used for neuronavigation. It helps to avoid mis-planning of surgical vectors and mis-placement of the used instruments.

Calibration↗

Neuroendoscopy based on computer assisted adjustment of the endoscope holder in the laboratory.

OBJECTIVE: We present our initial clinical experience with a novel technique of frameless stereotactic neuroendoscopy using a neuronavigation system, a specially designed aiming device (endoscope holder/targeting device) combined with a vacuum-mouthpiece based head holder. Due to the reproducibility of patient immobilization in the fixation system, the endoscope holder can be adjusted in the laboratory in the absence of the patient. METHODS: An individual vacuum-mouthpiece was fabricated. The patients were scanned with an external reference frame attached to this mouthpiece and the images were transferred to the neuronavigation system. Determination of the path, mouthpiece-based registration and adjustment of the targeting device were performed the day before surgery in the absence of the patient. In the OR the patient was repositioned and the endoscope was introduced through the preadjusted aiming device to the precalculated depth. RESULTS: The novel technique was successfully used for frameless endoscopic navigation in five patients. Three endoscopic third ventriculostomies in adults, one endoscopic septostomy due to unilateral hydrocephalus in an adult female patient and one endoscopic ventriculo-cysto cisternostomy in a 20-month-old girl with a suprasellar arachnoid cyst, were performed with excellent clinical results and without technical complications. CONCLUSION: Our initial experience indicates that frameless stereotaxy, in combination with a relocatable head holder and a special targeting device, allows for precise and preplanned advancement of the neuroendoscope, reducing or even eliminating intraoperative registration and endoscope trajectory adjustments, thus substantially reducing OR time. Due to the non-invasive but rigid immobilization method, neuronavigation can also be performed in children under 2 years of age.

Adult↗

Intraoperative Image-Guided Surgery of the Lateral and Anterior Skull Base in Patients with Tumors or Trauma.

The aim of this investigation was to evaluate the suitability and usefulness of the Stealth Stationtrade mark intraoperative guiding system (Medtronic Sofamor Danek, Memphis, TN) in a variety of indications. Eleven intraoperative image-guided procedures were performed for anterior or lateral skull base lesions. The most common neurosurgical approaches included frontal, coronal, and parietotemporal access. Neuronavigation reliably allowed the extent of tumor configuration and risk zones (e.g., blood vessels) to be visualized. Thus, gross tumor resection was achieved in 6 of 7 patients and facilitated reconstruction by the maxillofacial surgeon, resulting in radiologically symmetrical and clinically satisfying results. Postoperatively, one patient was blind from a continuity defect of the optic nerve caused by a bone fragment. Despite destruction of anatomical landmarks related to tumor invasion or intraoperative bone removal, neuronavigation proved helpful in the reconstruction of bony structures. Overall, the use of neuronavigation in interdisciplinary surgery for complicated tumors or trauma of the anterior or lateral skull base allows more radical resection associated with less morbidity.

Journal Article↗

The insular lobe: physiopathological and surgical considerations.

OBJECTIVE: Surgery of the insula represents a technical challenge, because of the proximity of the internal capsule to the lenticulostriate arteries and the lack of certainty concerning its functionality. Using intraoperative direct cerebral stimulation, combined with neuronavigation, the authors operated on 12 insular gliomas. On the basis of this experience, the physiopathological and surgical implications are discussed. METHODS: A low-grade insular glioma, revealed by seizures, was diagnosed in 12 right-handed patients with a normal neurological status. Preoperative magnetic resonance imaging showed that, according to Yasargil's classification system, three patients harbored Type 3 lesions and nine patients had Type 5 lesions (10 tumors on the right side and 2 on the left dominant side). All patients underwent surgery using direct cerebral stimulation, under general anesthesia in nine patients (motor mapping) and under local anesthesia in three patients (sensorimotor and language mapping). Ultrasonography and/or neuronavigation was used in all cases. Preoperative angio-computed tomographic scanning showed the lenticulostriate arteries in two patients. RESULTS: The internal capsule was systematically detected, and the language areas were identified within the left insula in the awake patients. The lenticulostriate arteries were seen in two patients. Seven patients presented an immediate postoperative deficit; six of them recovered completely within 3 months. Four resections were total, six were subtotal, and two were partial (left insula). CONCLUSION: The use of intraoperative direct cerebral stimulation and neuronavigation allows surgery of the insula with minimization of the risk of sequelae, but its use is still limited with regard to the dominant hemisphere, owing to the essential role of this structure in language.

Adult↗

Surgical management of single and multiple brain metastases: results of a retrospective study.

BACKGROUND: Advancement in diagnosis and treatment of various cancer entities led to an increasing incidence of brain metastases in the last decades. Surgical excision of single and multiple brain metastases is one of the central treatment options beside radiotherapy, radiosurgery and chemotherapy. To evaluate the benefit of surgery with/without whole-brain radiation therapy (WBRT) in single brain metastases and the influence of image guidance for brain metastases resection, 104 patients were retrospectively evaluated for post-operative outcome. PATIENTS AND METHODS: Between January 1994 and December 1999 150 patients were surgically treated for brain metastases at the Department of Neurosurgery at the Technical University of Dresden. Outcome could be evaluated in 104 patients with respect to special treatment strategies and survival time (69 patients with single and 35 patients with multiple lesions). RESULTS: Most metastases originated from primary lung and breast tumours. Karnofsky performance score improved on average by 10 after surgery. The extent of the extracerebral tumour burden was the main influence on survival time. Patients' age below 70 years was combined with prolonged survival time (median survival time, MST: 4.5 months vs. 7 months). Patients with solitary cerebral metastasis had a MST of 16 months, whereas patients with singular lesions had a MST of 7 and 4 months, depending on the extent of the extracerebral tumour growth. Additional post-operative WBRT with 30 Gy was combined with an increase in MST in patients with single brain metastasis (surgery + WBRT: MST 13 months; surgery only: MST 8 months). In addition, the rate of recurrent cerebral tumour growth was distinctly higher in the non-WBRT group. Neuronavigation did not significantly improve post-operative survival time. In 80% of patients extracerebral tumour growth limited patients' survival. CONCLUSION: Surgery is an initial treatment option in patients with single and multiple brain metastases especially with large tumours (> 3 cm). Post-operative WBRT seems to prolong survival time in patients with single brain metastasis by decreasing local and distant tumour recurrence. Neuronavigational devices permit a targeted approach. Multiple processes can be extirpated in one session without prolonging the hospitalisation time for the patient. However, neuronavigational devices cannot assure complete tumour resection.

Aged↗

Image-guided frameless stereotactic biopsy sampling of parasellar lesions. Technical note.

Interactive image-guided neuronavigation was used to obtain biopsy specimens of cavernous sinus (CS) tumors via the foramen ovale. In this study the authors demonstrated a minimally invasive approach in the management of these lesions. In four patients, whose ages ranged from 29 to 89 years (mean 61.2 years) and who harbored undefined lesions invading the CS, neuronavigation was used to perform frameless stereotactic fine-needle biopsy sampling through the foramen ovale. The biopsy site was confirmed on postoperative computerized tomography scanning. The frameless technique was accurate in displaying a real-time trajectory of the biopsy needle throughout the procedure. The lesions within the CS were approached precisely and safely. Diagnostic tissue was obtained in all cases and treatment was administered with the aid of stereotactic radiosurgery or fractionated stereotactic radiotherapy. The patients were discharged after an overnight stay with no complications. Neuronavigation is a precise and useful tool for image-guided biopsy sampling of CS tumors via the foramen ovale.

Adult↗

CT-guided neurosurgery: preliminary experience.

BACKGROUND: With the possibility of CT systems becoming more handy and sophisticated, intraoperative CT was introduced in a few neurosurgical Centres with better results in lesion removal and surgical outcome. METHOD: At our Institution a mobile CT scanner was recently used for intraoperative evaluation (Philips Tomoscan M). For 27 tumour resections performed with a neuronavigation system, and 23 deep brain electrode positioning examinations, an intraoperative CT was employed. In addition the CT scanner was used in the recovery room for a postoperative control in 198 patients. FINDINGS: Our preliminary experience used for a real time evaluation of the treated patients, permitted to verify an incomplete removal in 23/27 cases. Evaluation of stereotactic electrode position in relation to the planned target was also possible and demonstrated a correct position in 21 cases. INTERPRETATION: Intraoperative CT scan is a useful system that permits to modify neuronavigation planning and is able to give information to the surgeon for better tumour removal, rule out possible hemorrhagic complications, and suitable deep brain electrode positioning.

Adolescent↗

Glioma surgery evaluated by intraoperative low-field magnetic resonance imaging.

OBJECTIVE: To give an overview on intraoperative magnetic resonance (MR) imaging in glioma surgery. MATERIAL AND METHODS: MR imaging was performed using a 0.2T scanner, located in a radiofrequency-shielded operating theatre. Two setups were used: surgery either in a neighbouring operating theatre, or directly at the 5G line. Additionally, in gliomas adjacent to eloquent brain areas microscope- or pointer-based neuronavigation with integrated functional data was applied. 106 gliomas were among the 330 patients investigated in the last 5 years. RESULTS: We did not observe complications attributable to intraoperative MR imaging. Image quality was sufficient to evaluate the extent of the tumour resection in the majority of cases. Intraoperative imaging revealed remaining tumour in 63%. In a total of 26% patients further tumour could be removed due to the results of intraoperative imaging, increasing the rate of complete tumour removal especially in the low-grade tumours. The additional use of functional neuronavigation prevented an increased morbidity. CONCLUSION: Intraoperative MR imaging offers the possibility of further tumour removal during the same surgical procedure in case of tumour remnants, increasing the rate of complete tumour removal. The effects of brain shift can be compensated for using intraoperative image data for updating.

Adolescent↗

Intraoperative MRI for interventional neurosurgical procedures and tumor resection control in children.

INTRODUCTION: Despite the introduction of neuronavigational systems, radical tumor removal is still problematic in many neurosurgical procedures. Thus, direct intraoperative imaging for tumor resection control was implemented with an intraoperative magnetic resonance imaging (ioMRI) scanner installed in the operating room. Whereas most procedures with ioMRI were carried out in adults, we summarize 7 years of experience using ioMRI in children for interventional neurosurgical procedures or for tumor resection control. METHOD: An open magnetic resonance scanner (Magnetom Open 0.2 T) was installed in the neurosurgical operating room. For tumor resection control, ioMRI was performed in 35 procedures. After the ioMRI scans were analyzed with respect to quality, the identification of residual tumor was considered by the attending neuroradiologist and neurosurgeon. If residual tumor tissue was present, a new three-dimensional (3D) dataset was acquired to update the neuronavigation; subsequently, the tumor resection was extended. In all these procedures, the results of the ioMRI were checked by an early postoperative high-field magnetic resonance imaging (MRI) study. In addition, ioMRI was carried out in ten other children to monitor interventional neurosurgical procedures. RESULTS: In all children, ioMRI was adequate both for tumor resection control and monitoring of interventional procedures. Primary radical removal of tumor was reached in 40% as confirmed by ioMRI, but in 60% of the patients, the tumor resection procedure was extended after residual tumor was detected using the new 3D dataset for navigational update. By using ioMRI, radical tumor removal improved up to 83% as confirmed by early postoperative MRI. Procedure-related complications were not seen in our series. For all MR-guided biopsies, histology findings could be confirmed, and aspiration of intracranial cysts or abscesses could be monitored online. CONCLUSION: IoMRI using the open magnetom is suitable for detecting residual tumor tissue, can compensate for the phenomenon of brain shift using a new intraopertive 3D dataset for extended tumor resection, and is capable of monitoring interventional neurosurgical procedures. By using ioMRI for tumor resection control, the degree of tumor resection could be significantly improved.

Adolescent↗

The role of magnetoencephalography in pediatric epilepsy surgery.

INTRODUCTION: Magnetoencephalography (MEG) is a new diagnostic imaging and brain mapping device that has been recently used in the context of pediatric epilepsy, epilepsy surgery, and neuronavigation. PRINCIPLES OF MAGNETOENCEPHALOGRAPHY: MEG allows for the placement of magnetic spike sources on a conventional magnetic resonance imaging scan, the so-called magnetic source imaging, so that the localization of epileptiform activity in a child can be determined. Considerable effort is placed on analyzing the configuration and number of spike waves by MEG that relate to a primary epileptiform discharge. Such MEG spike clusters are corroborated now by intraoperative invasive subdural grid monitoring that show good correlation in the majority of cases. Another important role of MEG relates to the mapping of critical regions of brain function using known paradigms for speech, motor, sensory, visual, and auditory brain cortex. FUTURE APPLICATIONS: When linked to standard neuronavigation devices, MEG brain mapping can be extremely helpful to the neurosurgeon approaching nonlesional epilepsy cases or lesional cases where the safest and most direct route to the surgical disease can be selected. As paradigms for brain mapping improve and as MEG software upgrades become more sensitive to analyzing all types of spike sources, MEG will play an increasingly important role in pediatric neurosurgery, especially for the child with intractable epilepsy.

Brain Mapping↗

Multimodal protocol for awake craniotomy in language cortex tumour surgery.

BACKGROUND: Intra-operative neurophysiological language mapping has become an established procedure in patients operated on for tumours in the area of the language cortex. Awake cranial surgery has specific risks and patients are exposed to an increased physical and mental stress. The aim of the study was to establish an algorithm that enables tailoring the neurosurgical and anaesthetic techniques to the individual patient. METHOD: A total of 25 patients underwent awake craniotomy for intra-operative language mapping between 1999 and 2004. Following craniotomy under analgesia and sedation without rigid pin fixation of the head, cortical language mapping was performed in the fully co-operative patient. The results of functional magnetic resonance imaging and of cortical language mapping were incorporated into the 3D dataset for neuronavigation. Depending on the functional data and the individual operative risk tumour resection then proceeded either under conscious sedation with the option of subcortical language monitoring or under general anaesthesia. FINDINGS: After cortical language mapping patients are assigned to one of four groups: BACC (Berlin awake craniotomy criteria) I-IV. BACC I (9 patients): adequate functional data+operative risk not increased-->tumour resection in the awake patient; BACC II (4 patients): limited functional data+operative risk not increased-->tumour resection in the awake patient with the option of language monitoring as needed; BACC III (9 patients): adequate functional data+increased operative risk-->tumour resection under general anaesthesia using functional navigation; BACC IV (3 patients): limited functional data+increased operative risk-->tumour resection in the awake patient with the option of language monitoring as needed. We observed less adverse events in group BACC III. No permanent deterioration of language function occurred in this series. CONCLUSIONS: The multimodal protocol for awake craniotomy provides for tumour resection under general anaesthesia in selected patients using functional neuronavigation. Our experience with the algorithm suggests that it is a useful tool for preserving function in patients undergoing surgery of the language cortex while reducing the operative risk on an individual basis.

Adult↗

Image-guided ultrasonography for recurrent cystic gliomas.

BACKGROUND: Long-term survival of patients with recurrent gliomas depends on the extent of resection. Thus, the desirability of an intra-operative imaging modality that can augment the resection extension without affecting vital surrounding structures is more than obvious. It was the aim of the present study to evaluate a possible benefit of image-guided intra-operative ultrasonography for the surgery of recurrent gliomas. METHOD: The authors performed ultrasonography-assisted image-guided resection of recurrent gliomas in 16 patients. An ultrasound device (IGSonic) was integrated into the VectorVision2 navigation system (BrainLAB, Heimstetten, Germany). The IGSonic Probe 10V5 was connected to the VectorVision Navigation station via an IGSonic Device Box. Following patient registration, MRI based neuronavigation was used to determine the skin incision and the bone flap. Before opening the dura, the underlying structures were explored by ultrasound combined with the corresponding MR images. The navigated ultrasound displayed the sonographic image of the intracranial anatomy on the navigation screen in a composed overlay fashion. FINDINGS: The integration of intra-operative ultrasound into neuronavigation system offered quick and helpful intra-operative images in all 16 procedures. Due to the specific ultrasonic characteristics of the solid and the cystic parts, our technique created highly useful images in 10 patients with cystic recurrences. In these, user friendly images were obtained that were easy to understand even for neurosurgeons without major experience in intra-operative ultrasound. CONCLUSIONS: Neurosonography is a time- and cost-effective technology offering intra-operative imaging. The improved orientation and visualization of tumour remnants, adjacent ventricles, and the enhanced intra- and peri-tumoural vasculature is one of the main advantages of ultrasonography-assisted image-guided surgery, which is most obvious during surgery for cystic gliomas.

Brain Neoplasms↗

Transbasal approaches: surgical details, pitfalls and avoidances.

Lesions involving the anterior skull base and sphenoclival region are difficult surgical problems. This paper presents surgical details, pitfalls, avoidances and our experiences in the surgical treatment of lesions of the anterior skull base using neuronavigation. Between 1999 and 2003, 33 patients with pathology of the anterior skull base were operated on via the traditional transbasal and the extended transbasal approach. A passive-marker-based neuronavigation system has been used for intraoperative image guidance since April 2000. The patients consisted of 11 men and 22 women. Their ages ranged from 3 to 76 years, with a mean of 41 years. The lesions for which the approach was used included 9 cerebrospinal fluid (CSF) fistulae and 24 neoplastic lesions including meningioma (16 cases), metastasis (3 cases), chordoma (3 cases), plasmacytoma (1 case), and osteoma (1 case). Gross total removal of the tumors was accomplished in 22 out of 24 patients with tumor (91.6%). Postoperative complications include CSF leakage (2 cases), infection (2 cases) and transient impaired vision (1 case). One patient (3%) died postoperatively from hypothalamic dysfunction after removal of a benign tumor extending to the anterior third ventricle. Despite the incidence of postoperative infection and the high rate of CSF leakage and death, it is possible to obtain long-term survival for patients with tumors previously considered challenging and difficult surgical problems.

Adolescent↗

Microsurgery for cerebral arteriovenous malformation management: a Siberian experience.

Cerebral vascular malformations remain among the most difficult neurosurgical entities to treat. We report a retrospective study of the outcome in 95 consecutive patients with angiographically revealed arteriovenous malformations (AVMs). Fifty-four patients underwent microsurgical total AVM removal (group I). Forty-one patients who refused open surgery (group II) were managed either by endovascular embolisation (16 cases), radiosurgery (three) or followed up with medical treatment for their symptoms. In the first group pretreatment with the non-selective beta-blocker propranolol before surgery, the current neuronavigation techniques, intraoperative embolisation and AVM nidus colouring in high flow AVM were used for total microsurgical excision of the lesions. All AVM patients but one survived microsurgery. The mortality rate was 1.8% for group I. Six patients with grade IV-V AVM developed new temporal neurological symptoms following surgery. Four of them recovered completely in 3-6 weeks; two patients remained with mild persistent monoparesis and with homonymous hemianopsia postoperatively. In ten of 13 epileptic patients surgery produced a cure. No patient re-bled following surgery. No postoperative normal perfusion pressure breakthrough occurred. In the second group ten patients (24%) developed intracerebral haemorrhages, six of ten patients demonstrated progressive seizures. The mortality rate in group II totalled 17% over 6 years. Microsurgical management approaches must consider preoperative correction of impaired cerebral autoregulation, neuronavigation for preoperative planning and intraoperative orientation, intraoperative embolisation and dying of the nidus for large high-flow AVMs.

Adolescent↗

Navigated repetitive transcranial magnetic stimulation for post-stroke recovery: A systematic review and meta-analysis of randomized controlled trials.

Repetitive transcranial magnetic stimulation (rTMS) is a subcategory of non-invasive brain stimulation (NIBS), used to modulate brain plasticity and improve post-stroke recovery. Neuronavigation is used to improve the accuracy of stimulation with the aim of achieving a superior clinical outcome than with conventional targeting. The objective of this review is to evaluate the efficacy of navigated rTMS in subacute and chronic stroke patients in comparison to sham stimulation. We conducted a systematic-review and meta-analysis of randomized controlled trials (RCTs) identified from Pubmed, Scopus and Cochrane CENTRAL. Trials employing neuronavigated rTMS were included of these five types; high and low frequency rTMS, intermittent and continuous theta-burst stimulation (TBS) and Hebbian-type stimulation. 13 RCTs were included after a screening of 1900 studies. 606 patients receiving either active (n = 360) or sham stimulation (n = 246) were assessed. The pooled standardized mean difference (SMD) favored rTMS over sham SMD = 0.4 (95 %CI: 0.11-0.69), with moderate heterogeneity I2 = 55 %. Among stimulation modalities, continuous TBS showed the largest pooled effect. rTMS was also associated with significant improvements in disability-related outcomes, SMD = 0.61 (95 % CI 0.14-1.08). Navigated rTMS is associated with modest but significant improvements in motor and disability outcomes in subacute and chronic stroke. Large comparative trials are required to clarify the potential added value over conventional targeting approaches.

Humans↗

Long-term effects of repetitive transcranial magnetic stimulation (rTMS) in patients with chronic tinnitus.

OBJECTIVES: The pathophysiologic mechanisms of idiopathic tinnitus remain unclear. Recent studies demonstrated focal brain activation in the auditory cortex of patients with chronic tinnitus. Low-frequency repetitive transcranial magnetic stimulation (rTMS) is able to reduce cortical hyperexcitability. STUDY DESIGN: Fusing of the individual PET-scan with the structural MRI-scan (T1, MPRAGE) allowed us to identify exactly the area of increased metabolic activity in the auditory cortex of patients with chronic tinnitus. With the use of a neuronavigational system, this target area was exactly stimulated by the figure 8-shaped magnetic coil. In a prospective study, rTMS (110% motor threshold; 1 Hz; 2000 stimuli/day over 5 days) was performed using a placebo controlled cross-over design. Patients were blinded regarding the stimulus condition. For the sham stimulation a specific sham-coil system was used. Fourteen patients were followed for 6 months. Treatment outcome was assessed with a specific tinnitus questionnaire (Goebel and Hiller). SETTING: Tertiary referral medical center. RESULTS: Increased metabolic activation in the auditory cortex was verified in all patients. After 5 days of verum rTMS, a highly significant improvement of the tinnitus score was found whereas the sham treatment did not show any significant changes. The treatment outcome after 6 months still demonstrated significant reduction of tinnitus score. CONCLUSION: These preliminary results demonstrate that neuronavigated rTMS offers new possibilities in the understanding and treatment of chronic tinnitus.

Adult↗

Evaluation of invasiveness and efficacy of 2 different keyhole approaches to large basal ganglia hematomas.

BACKGROUND: The aim of this study was to evaluate the invasiveness and efficacy of 2 different keyhole approaches to large basal ganglia hematomas (LBGHs). METHODS: The invasiveness and efficacy of the temporal (15 cases) and the frontal (15 cases) microsurgical keyhole approach were retrospectively evaluated in 30 early-operated patients with LBGH, using recorded neuronavigation data. Invasiveness was assessed calculating the angles of brain retraction and the volume of brain exposed to surgery. Reduced invasiveness was related to a fall of these values. Efficacy was evaluated by comparing the volume of microscopically visualized clot and the largest hemorrhage diameter exposed with the 2 different keyhole approaches. Increased efficacy was related to a rise in these parameters. All estimations were correlated to the volume of residual clot detected on postoperative computed tomography scan. RESULTS: The comparison between both approaches revealed a significant reduction of invasiveness (smaller angles of brain retraction [P<.001] and reduced brain exposition [P<.001]), as well as a raised efficacy (increased volume of visualized clot [P<.001] and largest hemorrhage diameter exposed to surgery [P<.001]) for frontally approached LBGH. These patients showed less postoperative residual hematomas (P<.05). Residual clots were correlated to the evaluated brain retraction (P<.001) and volume of brain (P<.001), as well as volume of clot surgically exposed (P<.05). CONCLUSION: We conclude that the frontal approach to LBGH leads to less invasiveness and higher efficacy as evaluated by using neuronavigation data. This approach shows a reduced number of patients with residual postoperative clots.

Adult↗