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Background: We present our experience using a standardized transnasal transclival approach (TTA) for endoscopic removal of chordomas of the clivus., Patients: 13 patients with clival chordoma (CC) underwent tumor resection. Patients were operated by a surgical team consisting of a rhinosurgeon and a neurosurgeon. All patients underwent postoperative proton radiotherapy. Residual tumor was left in situations where radical removal would have entailed an increased risk of neurological deficits., Results: Radical or near total removal of CC was accomplished in 12/13 patients. Intraoperative MRI (IMRI) was used in 4/13 CC patients. A watertight dural seal presented as the main challenge specifically for tumor extensions resulting in large dural defects., Conclusion: The TTA provides an elegant alternative to classical approaches to clival lesions especially for midline tumor locations. For large tumors iMRI is of significant help. Dural reconstruction of large defects emerged as the greatest challenge of this technique even for experienced endoscopic surgeons., (© Georg Thieme Verlag KG Stuttgart · New York.)

Introduction: Surgery in the temporomesial region is generally performed using a subtemporal, transtemporal, or pterional-transsylvian approach. However, these approaches may lead to approach-related trauma of the temporal lobe and frontotemporal operculum with subsequent postoperative neurological deficits. Iatrogenic traumatisation is especially significant if surgery is performed in the dominant hemisphere., Methods: During a five-year period between January 2003 and December 2007, we have approached the temporomesial region in 21 cases via the supraorbital approach. In 15 cases, the lesion was located within the dominant hemisphere, all lesions had space-occupying effects. In all cases, meticulous approach planning was performed, demonstrating a close proximity of the lesion to the pial surface on the upper anterior mesial aspect of the temporal lobe. An extension within the parahippocampal gyrus or with deep temporobasal tumor growth below the sphenoid wing were considered as exclusion criteria for using the supraorbital approach., Results: In all cases surgery was performed without intraoperative complications. Pathological investigation showed 7 low-grade astrocytomas, 4 high-grade astrocytomas, 2 gangliogliomas and 2 cavernomas. Early postoperative MRI scans confirmed a complete removal of the lesion in 14 cases. In one case of a subtotal resection, the residual tumor was removed through a posterior subtemporal approach. The postoperative neurological examination was unchanged in 14 cases. In one case a transient hemiparesis was observed. In patients with dominant-sided lesions no speech or mental deficits were present., Conclusion: In selected cases, the minimally invasive supraorbital craniotomy offers excellent surgical efficiency in the temporomesial region with no approach-related morbidity compared to a standard transtemporal or pterional-transsylvian approach., (Georg Thieme Verlag KG Stuttgart * New York.)

Introduction: Surgical management of multiple intracranial aneurysms may be difficult if located bilaterally. In the case of bilateral middle cerebral artery (MCA) aneurysms, surgical treatment through a unilateral approach is generally not recommended. In this study we describe the surgical technique and important factors that enable treatment of bilateral MCA aneurysms via a unilateral key-hole approach., Patients and Methods: 15 patients (12 females, 3 males) with bilateral aneurysms of the MCA were surgically treated via a supraorbital key-hole approach. Age ranged from 37 to 60 years (mean: 47). 7 of the 15 patients presented with an acute subarachnoid hemorrhage (SAH). Cerebral angiography was performed in all patients pre- and postoperatively. Patients suffering from SAH were treated within the first 72 h. All 15 patients were planned to be operated via a unilateral supraorbital keyhole craniotomy using an eye-brow incision., Results: In 10 of the 15 patients MCA aneurysms of both sides could be occluded completely through the unilateral approach. In 5 patients bilateral craniotomies had to be performed, in 1 of these patients during the same procedure. Factors necessitating a second craniotomy were brain swelling (1 patient with SAH), insufficient instruments (2 patients), and complex configuration of the contralateral aneurysm (2 patients). Permanent morbidity was anosmia in 1 patient and hyposmia and a mild visual field deficit in 1 further patient., Conclusion: Bilateral aneurysms of the MCA may be treated sufficiently through a unilateral supraorbital key-hole approach in selected patients. This is also possible in patients presenting with SAH. Factors necessitating bilateral craniotomies were brain swelling and complex configuration of the contralateral aneurysm., (Copyright Georg Thieme Verlag KG Stuttgart. New York.)

Cavernomas are often small in size and located in difficultly accessible regions. Preoperative identification of the ideal surgical approach as well as the precise intraoperative implementation of the surgical plan are of critical importance for successful surgery. While aiming for minimally invasive surgical techniques and maximally effective cavernoma resection, we envisaged that employing a combination of precise and technically sophisticated virtual reality surgery planning, modern navigation systems with augmented reality features and endoscope-assisted surgical techniques should contribute to achieve this goal. Between December 2002 and November 2005, 66 patients were operated on for cerebral cavernomas in our department. In 23 cases surgery planning was done by using a virtual reality planning system, neuronavigation was used in 43 cases and the intraoperative augmented reality feature was used in 16 cases. 10 patients were operated by using the endoscopic assisted surgical technique. Complete resection was achieved in all cases. Using all nowadays available surgical tools, cerebral cavernomas can be operated with minimally invasive techniques and with excellent results.

Background: Neuronavigation is a commonly used technology that provides continuous, three-dimensional information for the precise localization of and surgical trajectory to brain lesions. This study was performed to evaluate the role that navigation can play in assisting microsurgical transsphenoidal surgery for precise localization and removal of recurrent pituitary tumours while simultaneously preserving pituitary gland function., Method: During a 6-month period -- July 2004 until December 2004 -- 9 patients with recurrent pituitary tumours (5 female and 4-male) were treated with navigation-guided transsphenoidal microsurgical resection. Surgery was performed via a paraseptal or endonasal transsphenoidal approach. The navigation system Vector Vision (Brain Lab, Heimstetten, Germany) allowed precise localization of the tumours (7 hormonal active and 2 inactive microadenomas) in respect to the pituitary gland, the carotid arteries and the cavernous sinus., Results: Postoperative MRI investigations of the 9 patients treated with image-guided transsphenoidal microsurgery, showed total tumour removal in 7 (77 %) patients and subtotal removal in 2 patients (23 %). One patient (11 %) developed a cerebral spinal fluid (CSF) leak and was treated conservatively. One patient (11 %) had preoperative insufficiency of the corticotrope axis which remained unchanged postoperatively. Of the remaining 8 patients who did not have preoperative endocrinological disturbance, only one (12 %) developed postoperative insufficiency of the corticotrope axis. Out of the 7 patients with hormone active tumours, 5 (72 %) patients showed no more postoperative hormonal activity., Conclusion: Microneurosurgical transsphenoidal techniques combined with image-guided systems can precisely define the localization and removal of lesions in the sella region with respect to the margins of important anatomical structures in the neighbourhood and the endocrinological functionality of the pituitary gland.

Continuous improvement of surgical techniques is needed in skull base surgery in order to decrease intraoperative complications during various operations. However, the basis of minimizing damage in the operative field is a comprehensive knowledge of microsurgical anatomy. This article provides a detailed description of the cribriform plate and adjacent areas, based on investigations of over one thousand dried skulls and 225 computerized tomography scans of the anterior skull base. The main anatomic structures and the different types of the cribriform plate are demonstrated on color photographs and identified on CT scans as well. The variations important in anterior skull base approaches are also discussed and compared with the data found in the literature. The surface anatomy and development of the cribriform plate is described.

Cubital tunnel syndrome is the second most common entrapment neuropathy in the upper limb; however, surgical treatment of the ulnar nerve entrapment at the elbow remains controversial. None of the presently advocated procedures (simple decompression of the ulnar nerve, medial epicondylectomy, subcutaneous, submuscular or intramuscular anterior transposition of the ulnar nerve) has proven optimal regarding long-term results. This paper presents the experience of treating cubital tunnel syndrome with simple decompression in 40 patients. Three months after surgery 23/36 patients did not feel any pain in their operated hands. In 11/36 cases we observed an improvement of preoperative pain. Sensory disturbances disappeared completely in 24/40 cases. 11/40 patients reported an improvement of preoperative dysesthesia or hypesthesia. In 12/22 patients we observed complete recovery of preoperative pareses of adductor muscle of thumb or hypothenar muscles weakness. 7/22 cases demonstrated an improvement of these pareses. In total 28 patients (70 %) had an excellent outcome without residual symptoms. For 5 patients treatment results were classified as good with slight residual pain and sensory disturbance (12.5 %). In 4 cases (10 %) we only observed a fair outcome with persistent severe sensory and motor deficits but slow improvement over the last three months. Three patients did not demonstrate any improvement (7.5 %). The mean duration of postoperative disablement in our working patients (18/40) was 28 days. In summary, simple decompression of the ulnar nerve seems to be an adequate and successful minimally invasive technique for the treatment of cubital tunnel syndrome.

The endoscopic carpal tunnel release is a new minimally invasive method which has been used to decompress the median nerve in the carpal tunnel for the past decade. Advantages of this method should be a decreased postoperative morbidity and earlier return to work. Preoperative complaints, postoperative results and complications of the therapy for a total of 60 patients are presented. All endoscopic releases were performed using the Agee uniportal technique. The overall success rate in our study was 56/60 (93.3 %). 47/54 (87.0 %) patients were completely free of pain after endoscopic surgery. An improvement in preoperative pain was noted in 4/54 (7.4 %) patients. Hypesthesia and dysesthesia disappeared totally in 39/46 (84.8 %) patients. An improvement of the sensible disturbances was observed in 4/46 (8.7 %) cases. 10/13 (76.9 %) preoperative pareses recovered completely, 3/13 (23.1 %) remained unchanged. The complication rate in total in our series was 4/60 (6.7 %), thereof 3 cases of post-operative infection (5 %) and one serious median nerve injury (1.7 %). The mean time for return to work was 29 days. Summing up, it may be said that monoportal endoscopic carpal tunnel release appears to be an effective and safe minimally invasive method for the treatment of carpal tunnel syndrome.

Controversy surrounds the treatment of recurrent cubital tunnel syndrome after previous surgery. Irrespective of the surgical technique, namely pure decompression in the ulnar groove and the cubital tunnel distal of the medial epicondyle, and the different methods of volar transposition (subcutaneous, intramuscular, and submuscular), the results of surgical therapy of cubital tunnel syndrome are often not favorable, especially in cases of long-standing symptoms and severe deficits. Twenty-two patients who had previously undergone surgical treatment for ulnar nerve entrapment at the elbow were evaluated because of persistent or recurrent pain, paresthesia, numbness, and motor weakness. Ten patients had undergone a nerve transposition, 5 patients underwent a simple decompression of the ulnar nerve, and 7 patients experienced two previous operations with different surgical techniques. Two patients underwent surgery at our hospital, whereas 20 patients underwent their primary surgery at other institutions. Various surgical techniques were used during the subsequent surgery, such as external neurolysis, subcutaneous anterior transposition, and subsequent transfer of the nerve back into the sulcus. The causes of continued or recurrent symptoms after initial surgery included dense perineural fibrosis of the nerve after subcutaneous transposition, adhesions of the nerve to the medial epicondyle and retention of the medial intermuscular septum. The average follow-up after the last procedure was 7 months (2 - 20 months). All 7 patients with subsequent transfer of the ulnar nerve back into the sulcus became pain-free, whereas only 11 of 15 patients who had external neurolysis or subcutaneous transposition became free of pain or experienced reduced pain. The recovery of motor function and return of sensibility were variable and unpredictable. In summary, reoperation after primary surgery of cubital tunnel syndrome gave satisfactory results in 18 of 22 cases. Subsequent transfer of the ulnar nerve back into the sulcus promises to be useful in cases in which subcutaneous transposition had not been successful.

To evaluate the usefulness of transendoscopic sonography, we have studied the use of a new sonographic probe of 6 F diameter in 11 fresh specimens. We achieved a precise imaging of well known anatomic structures and, moreover, obtained an additional dimension in endoscopy, since the sonographic probe adds a transverse scan to the endoscopic view, like a mini-CT at the tip of the probe. In this way, we also examined the guiding characteristics of this imaging technique, both in real time and on-line. Our results promise further interesting aspects of this technique in minimally invasive neurosurgery and suggest that further development and clinical experience seem to be justified.

A preclinical cadaver study was performed to develop the technique of biportal neuroendoscopic dissection in the subarachnoid space of the basal cisterns and to test the feasibility, utility, and safety of this new technique. In 23 fresh post-mortem adult human cadavers and 2 formalin-fixed adult human head specimen a total of 33 biportal endomicrosurgical dissections into and within the basal cisterns were carried out. Following suction of cerebrospinal fluid from the subarachnoid space 0 degree-, 30 degrees-, and 70 degrees-lens-scopes (Aesculap AG, Tuttlingen, Germany) with outer diameters of 4.2 mm and trochars with outer diameters of 5 to 6.5 mm were introduced into the surgical field. 6 different endoscopic routes to the basal cisterns and a total of 10 different combinations of these approaches for biportal endoneurosurgery could be described, but it was found that not all of them were useful and safe. The transventricular approach to the prepontine cisterns through the foramen of Monro and the floor of the third ventricle, biportally combined with a subfrontal or a subtemporal approach, turned out to be not safe enough as it was accompanied by traumatization of the fornix at the interventricular foramen and of the hypothalamus at the level of the tuber cinereum due to relaxation and caudal shift of the brain following suction of cerebrospinal fluid to clear the basal cisterns for the subfrontal or subtemporal approaches. Useful and safe endomicrosurgical approaches to the basal cisterns were: 1st subfrontal, either epidural or intradural, 2nd subtemporal, either anterior or posterior, and 3rd frontal interhemispheric. Various biportal combinations of these approaches are estimated to be feasible, useful, and safe enough to be performed during microsurgical procedures in the operating room. The biportal endomicrosurgical strategy allows for effective and safe dissections within the subarachnoid spaces of the basal cisterns. The tip of the microinstruments as well as the neighboring anatomical structures can be nicely controlled at angles of about 60 degrees to 180 degrees depending on the viewing angles of the scopes used and depending on the individual shape of the head. A variety of microsurgical instruments has been tested. A number of these will have to be redesigned for this new technique. Regions suitable for biportal neuroendoscopic subarachnoid preparations are the olfactory groove, the prechiasmatic cistern, the region of the optic chiasm, the entire suprasellar area, parts of the parasellar area, the pre- and perimesencephalic cisterns, and the prepontine cistern.

The osteofibrous space underneath the dura mater of the dorsoclival area was studied with respect to the arterial branches arising from the internal carotid artery at this level. Special attention was given to the main variations of branching and anastomosing patterns found in this area. Our results indicate that the meningohypophyseal trunk is the main supplier of the dorsoclival area. The dorsal meningeal artery was present in all cases. In the course of this vessel three main variations were observed. The inferior hypophyseal and the tentorial artery also contributed to the arterial supply of this region. A large number of anastomoses between the internal and external carotid artery was present as well. Because of the refinement of microsurgical and interventional techniques pathological lesions like tumors and vascular malformations of the dorsoclival area are frequently accessible. The knowledge of the microvascular anatomy of the clivus and the dorsum sellae is important as the rich collateral network found in this area may contribute to the arterial supply of pathological lesions arising here.

50 meningohypophyseal trunks of the intracavernous internal carotid artery were studied in 25 human cadavers. Special attention was given to the main variations of branching patterns of this trunk. The dorsal meningeal arteries were found in all cases and three typical variations were observed in their origins and courses: a prominent medial branch (52%), a bifurcating type (38%) or a single lateral branch was present (10%). The tentorial artery of Bernasconi-Cassinari arised as a single branch in 64% of the cases, while in 36% two or more branches took a direct origin from the main trunk. The inferior hypophyseal artery was prominent in 82% of the cases. The inferolateral trunk had a common origin with the meningohypophyseal trunk in 8% of our dissections. A large number of anastomoses between these vessels was observed. As a number of tumorous and vascular pathologies, which can be treated with microsurgical techniques, take their origin from the cavernous sinus, the knowledge of the smaller vessels arising from the intracavernous internal carotid artery as well as their main variations is important.