Interdisciplinary reconstruction of oncological resections at the skull base, scalp and facial region.

Extensive bone and soft tissue defects of the skull require unique plastic and reconstructive techniques to avoid and optimize aesthetic appearance following oncological resections. Procedures are ideally planned in an interdisciplinary board composed of neurosurgery, otorhinolaryngology, plastic and reconstructive surgery to facilitate reconstructive procedures of soft tissue and bone as early as possible in one approach. Large resections may require plastic surgery involvement from the beginning. Herein, we describe the function of a multidisciplinary approach to complex oncologic resections of the cranial base, scalp, and facial regions for neuro-oncologic patients.

Histopathological features of the brain, liver, kidney and spleen following an innovative polytrauma model of the mouse.

OBJECT: Among the various introduced experimental traumatic brain injury models, there is a clear paucity of proper experimental polytrauma models. To overcome this experimental gap we introduced such a polytrauma model in the mouse including traumatic brain injury. Here, we report on the histopathological features of the brain, lung, kidney, spleen and liver. MATERIALS AND METHODS: 20 male C57BL mice with a mean weight of 23 g were anesthetized with ketamine and xylazine. The anaesthetized animals were subjected to a controlled cortical impact (CCI) over the left parieto-temporal cortex using rounded-tip impounder for application of a standardized brain injury. Following fracture of the right femur using a guillotine, a volume-controlled hemorrhagic shock was induced. The control groups included animals with CCI only (n=20) and animals with femur fracture plus hemorrhagic shock without CCI (n=20). Subjects were sacrified at 96 h following trauma. Brain, lung, kidney, spleen and liver of the animals underwent histopathological examinations. RESULTS: The mortality rate at 96 h was 25% in the polytrauma group versus 10% in the control groups. Within the histopathological investigations, polytraumatized animals differ from those with a single trauma (traumatic brain injury or femur fracture with hemorrhagic shock) with various severity. CONCLUSION: The findings of this study show that such a polytrauma model can be standardized resulting in a reproducible damage. This model fulfills the requirements of a standardized animal model. It allows adequate analogies and inferences to the clinical situation of a polytrauma in humans.

An electrophysiological study on the safety of the endoscope-assisted microsurgical removal of vestibular schwannomas.

BACKGROUND: Endoscopy is being increasingly used in skull base surgery. The issue of its safety, however, has not been definitely solved. METHODS: We evaluated the risk of thermal or mechanical iatrogenic nerve injury related to endoscope application during microsurgical removal of vestibular schwannomas (VS) in a prospective group of 30 patients (Group A). Main analysed parameters were electrophysiological monitoring data (auditory evoked potentials and EMG) during and after endoscopic observation. The structural and functional preservation of facial and cochlear nerves, radicality of tumour removal, and CSF leak rate were evaluated and compared to historical group of 50 patients (Group B), operated consecutively with classical microsurgical technique. RESULTS: No electrophysiological changes directly related to endoscope were registered. The rate of loss of waves I, II, and V did not depend on application of endoscope and was similar in both groups. The functional and general outcome was also similar. Endoscopic inspection provided early and detailed view of anatomical relations within cerebellopontine angle and internal auditory canal and confirmed completeness of tumour removal. Total tumour removal was achieved in all patients from Group A and in 49/50 from Group B. Useful hearing after the surgery had 17/30 patients in Group A and 26/50 in Group B. CONCLUSIONS: The application of endoscope during microsurgical removal of VS is a safe procedure that does not lead to heat-related or mechanical neural or vascular injuries. The actual significance of this additional endoscopic information, however, is related to the particular operative technique and experience of the surgeon.

Late outcome of surgical treatment of the non-specific neurogenic thoracic outlet syndrome.

OBJECTIVE: Despite the relatively high incidence of the thoracic outlet syndrome, diagnostic criteria, role of surgery and optimal operative approach remain controversial. The main goal of the current study is to determine the long-term outcome of operative treatment of a series of patients with non-specific neurogenic thoracic outlet syndrome. METHODS: A retrospective study of a consecutive group of patients with thoracic outlet syndrome was carried out. The indications for surgery relied on clinical examination. Patients with diffuse pain were excluded. In all cases, the supraclavicular approach was used. Main outcome measures were neurological status and subjective complains. RESULTS: Nineteen patients have been operated over a period of 5 years. Total number of surgeries was 23. Pain and paresthesia on exertion were the leading symptoms in all cases. The causes of thoracic outlet syndrome were fibromuscular compression in 43.5%, cervical rib alone or in combination with a fibromuscular component in 30.4% and the first rib in 26.1%. The average follow-up was 36.3 months. In 91.7%, improvement of at least 50% was observed; 20.8% of the patients were completely symptom-free, and in 25%, the improvement was 90%. Recovery of the pre-operative motor weakness was recorded in 66.6%. The mortality and the permanent morbidity rates of the procedure were 0%. DISCUSSION: Operative decompression of the brachial plexus via the supraclavicular approach in patients with non-specific neurogenic thoracic outlet syndrome is a safe procedure that leads to a significant neurological improvement and amelioration of complains. The indication for surgery should be based chiefly on the neurological and clinical findings.

Venous complications following petrosal vein sectioning in surgery of petrous apex meningiomas.

OBJECTIVE: Meningiomas involving the petrous apex regularly show a close relationship with the superior petrosal vein which is sometimes obliterated during surgery due to its proximity to the tumour. However, there is no study available so far focusing on the frequency of postoperative venous congestion related complications following petrosal vein obliteration as well as on pre- and intraoperative findings related to them. METHODS: Fifty-nine patients with meningiomas involving the petrous apex were analyzed concerning the intraoperative preservation or sacrifice of the petrosal vein and postoperative complications related to venous occlusion. RESULTS: When a petrosal vein was occluded, in 9 of 30 cases venous-related complications occurred with a minor venous-congestion phenomenon in seven cases and major complications in two cases. When the petrosal vein complex was preserved, there were no similar complications. CONCLUSION: Preservation of the petrosal venous complex, especially of large caliber veins, should be attempted whenever possible to increase the safety of surgery. In cases of petrosal vein obliteration, effective brainstem decompression following tumour removal is essential to minimizing the risk of cerebellar congestion.

Systemic effects of isolated brain injury: an experimental animal study.

OBJECTIVE: Although various experimental works of neurotrauma research are performed, little attention has been paid to the concomitant systemic changes following isolated traumatic brain injury (TBI). Such investigations seem to be a prerequisite condition for evaluation of experimental drugs, which may diminish the secondary damage following TBI. We describe histopathologic findings of the lung, liver, spleen and kidney 96 hours following an experimental TBI. METHODS: Ten male C57BI/6 mice were subjected to a controlled cortical impact (CCI) over the left parietotemporal cortex using rounded-tip impounder for application of a standardized brain injury. Subjects were killed 96 hours following trauma. Brain, lung, liver, kidney and spleen were preserved for morphologic examinations. RESULTS: Moderate histopathologic changes were evident in the lung and liver. The kidney and spleen seem not to be affected by the trauma regarding our examination. CONCLUSION: The findings of this study show that even isolated TBI can lead to a migration of immunocompetent cells to peripheral organs potentially leading to dysfunctions of peripheral organs to various extents. More attention to peripheral organs during experimental TBI research is indicated.

Hearing preservation after complete microsurgical removal in vestibular schwannomas.

AIM: To evaluate and present the treatment strategy and hearing preservation in a recent series of vestibular schwannoma cases. MATERIALS AND METHODS: A retrospective analysis of 200 patients operated consecutively over a 3 year period was performed. Patient records, operative reports, including data from the electrophysiological monitoring, follow-up audiometric examinations, and neuroradiological findings were analyzed. RESULTS: The anatomical integrity of the cochlear nerve was preserved in 75.8% of the cases. When only patients with preserved preoperative hearing were included, the rate was 84%. The overall rate of functional hearing preservation was 51%. It was highest in small tumors--60% in class T1 and 72% in class T2. In tumors extending to and compressing the brain stem, preservation of some hearing was possible in up to 43%. CONCLUSIONS: Vestibular schwannomas are benign lesions whose total removal leads to definitive healing of the patient. The goal of every surgery should be functional preservation of all cranial nerves. Using the retrosigmoid approach with the patient in the semi-sitting position, hearing preservation is possible even for large schwannomas.

Microsurgery management of vestibular schwannomas in neurofibromatosis type 2: indications and results.

AIM: To analyze the senior author's experience and strategy of treatment of patients with neurofibromatosis type 2 (NF2), with particular emphasis on vestibular schwannoma (VS) surgery. MATERIALS AND METHODS: Over a period of more than 35 years, the senior author (M.S.) has operated on more than 165 patients with NF2. The total number of VS surgeries was 210. This retrospective analysis includes 145 consecutively operated patients. Medical records, operative reports, follow-up neurological, audiometric examinations, and neuroradiological findings were analyzed. RESULTS: Total tumor removal was achieved in 85% of the operated tumors. In 15%, deliberately subtotal removal was performed for brain stem decompression and hearing preservation in the only hearing ear. The overall rate of hearing preservation was 35%. When only patients with preserved useful preoperative hearing were included, the rate was 65%. Bilateral hearing after surgery was preserved in 23% of the patients. The anatomical integrity of the facial nerve was preserved in 89%. CONCLUSIONS: The goal of VS surgery in patients with NF2 should be complete removal but not at the expense of functional impairment. Carefully individualized treatment strategy offers the possibility of prolongation of life and preservation of neurological functions.

Real-time 3T fMRI data of brain tumour patients for intra-operative localization of primary motor areas.

INTRODUCTION: In patients with tumours in or near the motor cortex reliable intra-operative identification of the precentral gyrus can be difficult due to anatomical dislocation. Maps of functional magnetic resonance imaging (fMRI) based on the blood oxygen level dependent (BOLD) effect are used to localize eloquent functional areas of the brain but require postprocessing for reduction of false positive activations. We set the focus of this study on the evaluation of feasibility and clinical usefulness of using real-time fMRI t-maps without postprocessing for pre-operative planning and intra-operative localization of functional motor areas. METHODS: Real-time fMRI t-maps from a 3-T MRI scanner were co-registered with MRI data. Ten patients were operated under general anaesthesia using 3D neuronavigation with integrated real-time fMRI t-maps. Surgical and functional outcome was compared to results of 12 patients who previously underwent wake surgeries. RESULTS: Good neurological outcome was achieved in all treated patients. Main activation clusters on fMRI real-time maps were easily identified. Co-registered real-time fMRI data without additional postprocessing were useful in planning the surgical approach. However, due to brain shift and large voxel size of BOLD contrast signals on t-maps exact localization of borders between tumours and functional areas was not possible intra-operatively. CONCLUSION: Our method is very simple to use and effective in guiding the neurosurgeon safely through minimally invasive craniotomies to tumours in eloquent areas without setting lesions to functional areas. Furthermore, the neurosurgeon is more independent when tumour location requires acquisition of fMRI data for pre-operative planning and intra-operative navigation.

Surgical planning for retrosigmoid craniotomies improved by 3D computed tomography venography.

OBJECTIVE: It is impossible to precisely anticipate the crooked course of the transverse and sigmoid sinuses and their individual relationship to superficial landmarks such as the asterion during retrosigmoid approaches. This study was designed to evaluate this anatomical relationship with the help of a surgical planning system and to analyze the impact of these in vivo findings on trepanation placement in retrosigmoid craniotomies. METHODS: In a consecutive series of 123 patients with pathologies located in the cerebellopontine angle, 72 patients underwent surgical planning for retrosigmoid craniotomies based on 3D volumetric renderings of computed tomography venography. By opacity modulation of surfaces in 3D images the position of the asterion was assessed in relationship to the transverse-sigmoid sinus transition (TST) and compared to its intraoperative localization. We evaluated the impact of this additional information on trepanation placement. RESULTS: The spatial relationship of the asterion and the underlying TST complex could be identified and recorded in 66 out of 72 cases. In the remaining 6 cases the sutures were ossified and not visible in the 3D CT reconstructions. The asterion was located on top of the TST in 51 cases, above the TST in 4 cases, and below the TST in 11 cases. The location of the trepanation was modified in 27 cases due to the preoperative imaging findings with major and minor modifications in 10 and 17 cases, respectively. CONCLUSION: Volume-rendered images provide reliable 3D visualization of complex and hidden anatomical structures in the posterior fossa and thereby increase the precision in retrosigmoid approaches.

The use of high-frequency electromagnetics in brain tumour surgery.

OBJECTIVE: The first commercially available high-frequency electromagnetic field (EMF) system promises additional functionality for neurosurgical procedures. In a prospective study, we evaluated the optimal use as well as the limitations of this system designed for vaporizing tissue and for coagulation in brain tumour surgery. METHODS: For the microsurgical treatment of 63 consecutive patients with various intracranial tumours, the EMF system was used in addition to the standard neurosurgical instrumentarium. The system was assessed with respect to its compatibility with the operating room environment. Furthermore, attention was given to the particular techniques required to use the system most effectively. The efficiency of the investigated tool was monitored throughout the study. RESULTS: The EMF system functioned properly in all procedures and did not cause any complications. Specific handling techniques and electrode tip configurations could be defined for optimal use of high-frequency electromagnetics for vaporization and coagulation in different intraoperative settings. Thereby, the efficiency of the device could be increased throughout the study while ineffective use decreased from 7 to 2 cases. Although this tool is designed ergonomically and offers high tactile control, it cannot be used submerged in cerebrospinal fluid or under continuous irrigation, which makes it necessary to use it in tandem with suction devices to obtain a clear view on the surgical field. CONCLUSION: Maneuvering with the EMF system was substantially different to both monopolar and bipolar systems, clearly necessitating a learning curve for the surgeon. This device was found to be a valuable complementary tool to standard electrosurgical instruments when applied effectively and with elaborated techniques.

Image-guided craniotomy for frontal sinus preservation during meningioma surgery.

OBJECTIVE: Preservation of the frontal sinus (FS) during the frontolateral approach to the skull base reduces morbidity, enhances patient comfort, and speeds up the surgical procedure. Due to its irregular outline, mental reconstruction of the borders of FS from two-dimensional images is challenging during surgery. This study was designed to evaluate the impact of neuronavigation on identification and preservation of the FS during frontolateral craniotomies. METHODS: Forty-five patients with pathologies located in the anterior skull base and in the parasellar region were included. A standard computed tomography (CT) sequence was obtained from each patient and uploaded onto an image-guidance system for volumetric rendering of 3D images. The outline of the FS was visualized and the distance between its lateral border and the mid-pupillary line (MPL) was measured. The results were used for navigated craniotomies and compared to the intra-operative findings. RESULTS: The FS was located medial, on and lateral to the MPL in 32, 4 and 9 cases, respectively. The individual outline of the FS could be identified with a mean target registration error of 1.4mm (+/-0.7 mm). The craniotomy could be custom-tailored for each patient according to the individualized landmarks while visualizing the lesion and the surgical landmarks simultaneously. Unintended opening of the frontal sinus or orbit did not occur in any of these cases. CONCLUSION: Image-guided craniotomies based on 3D volumetric image rendering allow for fast and reliable demarcation of complex anatomical structures hidden from direct view in frontolateral approaches. The outline of the frontal sinus and the orbit can be appraised at a glance providing additional safety and precision during craniotomy.

Epidermoid cysts of the cerebellopontine angle with extension into the middle and anterior cranial fossae: surgical strategy and review of the literature.

Epidermoid cysts are tumours, which contain keratin, cellular debris and cholesterol, and lined with stratified squamous epithelium. Clinically, epidermoid cysts behave like benign, slow-growing lesions. We present a 63 year-old man with a 6-month history of right periorbital pain and hypaesthesia in the area of the first and second branch of the trigeminal nerve. MRI revealed an epidermoid cyst of the cerebellopontine angle extending into the middle and anterior cranial fossae. Radical surgical removal of epidermoid cysts should be attempted, but a less aggressive surgical strategy should be considered if there is strong adherence to the surrounding brain tissue, particularly in eloquent areas. In this case, complete tumour removal was achieved via a suboccipital retrosigmoid approach.

Management of skull based meningiomas in the elderly patient.

BACKGROUND: The demographic evolution of Western society together with availability of modern imaging techniques leads to an increasing diagnosis of meningioma patients over 70 years of age. This raises the question of appropriate management of this histologically benign tumour in a geriatric population. DESIGN: Forty-three patients aged over 70 years were analyzed and matched in a retrospective study with a younger group of 89 patients according to tumour size, histology, symptoms, recurrence and presence of neurofibromatosis II. RESULTS: Changes in postoperative Karnofsky scores were not statistically different between the two age groups. Neurological outcome was worse among the younger group (12% vs. 7% deterioration). Regarding surgical complications we noted only a statistically significant higher infection rate in the geriatric age group. There was no peri-operative mortality. CONCLUSIONS: Age alone is not a criterion to deny a priori skull base surgery, since well selected geriatric patients may benefit from a meningioma operation that may enhance future quality of life.

Cavernous malformation of the internal auditory canal.

Cavernous malformations of the internal auditory canal are a rare clinical entity that, however, should be considered in the differential diagnosis of intracanalicular masses. Even though this type of malformation is usually associated with an evident gadolinium enhancement at MR examination, in some patients, like in this case, the signal characteristics may be not sufficiently specific to allow the correct preoperative diagnosis. Nevertheless, the clinical history, in particular, a rapid onset of cranial nerve deficits, lead to the suspicion of a vascular malformation.

Fetal arachnoid cyst of the quadrigeminal cistern in MRI and ultrasound.

CASE: The authors report a fetus with an arachnoid cyst of the quadrigeminal cistern without hydrocephalus at 30 gestational weeks. DISCUSSION AND CONCLUSION: We reviewed the literature and could find only 62 reported cases of arachnoid cyst of the quadrigeminal cistern. We present a case without hydrocephalus diagnosed by combining ultrasound (US) and magnetic resonance imaging (MRI). The fetus, born by normal delivery, was followed up and did not show hydrocephalus for 1 year. This combined prenatal study, which uses US and MRI, helps in dispensing proper counseling to parents and assists the gynecologist and the neurosurgeon in the pre- and postnatal management of this condition.

Trigeminocardiac reflex during skull base surgery: mechanism and management.

BACKGROUND: We study the occurrence and management of the trigeminocardiac reflex (TCR) during neurosurgical procedures for lesions of the skull base. METHOD: Two hundred patients underwent neurosurgical procedures for various skull base lesions and were evaluated retrospectively for the occurrence of the TCR during surgery. This phenomenon was defined as the onset of bradycardia lower than 60 beats/minute and hypotension with a drop in mean arterial blood pressure of 20% or more due to intra-operative manipulation or traction on the trigeminal nerve. FINDINGS: Sixteen patients (8%) had a TCR intra-operatively (7 vestibular schwannomas, 5 sphenoid wing meningiomas, 3 petroclival meningiomas, 1 intracavernous epidermoid cyst). In all 16 patients with a TCR the postoperative courses presented no complications that could be directly related to this intra-operative phenomenon. CONCLUSIONS: Due to the intracranial course of the trigeminal nerve several surgical procedures at the anterior, middle and posterior skull base may elicit the trigeminocardiac reflex. Continuous monitoring of hemodynamic parameters allows the surgeon to interrupt surgical manoeuvres immediately upon the occurrence of the TCR. This technique is sufficient for the heart rate and the arterial blood pressure to return to normal levels without the necessity of additional anticholinergic medication.

Surgical treatment of cerebellopontine angle meningiomas in elderly patients.

BACKGROUND: The aim of this study is to assess the morbidity and mortality of meningioma surgery in patients over 70 years of age harbouring a tumour at the cerebellopontine angle as one representative location of the posterior fossa in comparison with a matched group of young patients. METHOD: A retrospective analysis based on clinical charts, surgical records, histological records, imaging studies and follow up records was conducted to select patients over 70 years who underwent surgery for cerebellopontine angle meningiomas. Tumours with comparable size and location were matched with the younger group. FINDINGS: There were 421 meningiomas located in the cerebellopontine angle, 21 patients were older than 70 years (range 70-84). Median Karnofsky-Index at presentation was 80 (50-90), 16 patients had a physical status grading ASA 2 and 5 patients ASA 3. The average length of hospital stay was 22 days (7-99 days). The postoperative median Karnofsky score at time of discharge was 80 (50-90). The most common medical complication was postoperative pneumonia in 4 patients, among them 3 patients had lower cranial nerve disturbances postoperatively. There were 56 younger patients (mean age 52.4 years; range 24.5-69.75 years) with corresponding tumour size and location. Pre-op Karnofsky score was 80 (70-90), 53 patients were graded as ASA 2 and 3 patients as ASA 3. Length of hospital stay was 13.6 days (8-32 days). Post-op Karnofsky score was 80 (50-90). Among 5 patients with postoperative lower cranial nerve disturbances no patient had pneumonia postoperatively. There was no peri-operative mortality in either group. CONCLUSIONS: With modern neurosurgical techniques and neuro-anesthesia elderly patients with CPA meningiomas can be operated on with acceptable low morbidity and good neurological outcome but recovery from surgery lasts longer compared to younger patients. However, postoperative lower cranial nerve deficits in elderly patients may not be well tolerated compared with younger patients.

Volumetric analysis of the growth rate of incompletely resected intracranial meningiomas.

OBJECTIVE: Intracranial meningiomas are mostly considered to be slow growing tumors. However, only a few previous reports provide information on the growth rate of these tumors. The aim of this study was to determine the growth rates of intracranial meningiomas after subtotal resection, analysing their relation to radiological appearance and histological features. Results are compared with our previous analysis of growth rates in incidental meningiomas . METHODS: The hospital charts, follow up records and imaging studies were reviewed in 36 patients with subtotally resected intracranial meningiomas. The tumor growth rates were determined by calculating the absolute and relative growth rates and the tumor volume doubling times. RESULTS: In the group of 33 patients with histologically verified grade 1 meningiomas, the mean absolute growth rate was 1.51 cm (3)/year, the median relative growth rate and tumor doubling time was 14.18 %/year and 5.228 years. In young patients annual relative growth rates were significantly higher. The median annual relative growth rate of meningiomas with calcification was significantly lower than in tumors without calcification. Also tumors with hypo- or isointense T (2)-signals on MRI revealed a lower growth rate. There was no significant difference between males and females. Histological studies revealed 22 meningiomas of a meningotheliomatous subtype, 8 fibrous and 3 psammomatous meningiomas. The comparison of growth rates between these subtypes did not show any significant differences. In atypical meningiomas (WHO grade 2), absolute and relative growth rates were significantly higher and tumor doubling times shorter. CONCLUSION: The majority of intracranial meningiomas are slow growing tumors, although the growth rates may vary widely even among benign grade 1 meningiomas. In meningiomas after subtotal surgical resection, the age of the patients seems to present a predictive factor for tumor growth in analogy to our previous observation in incidental meningiomas. Significantly higher relative growth rates were detected in younger patients. Gender does not seem to play a major role as a predictive factor. Radiological features such as calcification or T (2)-signal intensity may provide additional information to predict the growth potential of meningiomas. Close clinical and radiological observation should be performed in young patients harboring tumors with absence of calcification or high T (2)-signal intensities due to the higher growth potential in this patient group.