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  • Author or Editor: Joachim M. Oertel x
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Juergen Piek, Joachim Oertel and Michael Robert Gaab

Object. Waterjet dissection represents a new minimally traumatic surgical method for dissection that can be used in various parenchymal organs, in which it allows highly precise parenchymal dissection while preserving blood vessels, resulting in reduced intraoperative blood loss. This study was performed to investigate the clinical application of this new technique in neurosurgical procedures, such as brain tumor resection and epilepsy surgery.

Methods. Thirty-four patients with gliomas (Grades II–IV), cerebral metastases, temporal lobe epilepsy, or cerebellar hemangioblastomas, and one patient with internal carotid artery (ICA) stenosis were treated surgically with the aid of the waterjet. Resection was performed using waterjet dissection in combination with conventional neurosurgical procedures. Intraoperatively, the waterjet was easy to handle, and no complications due to the device were observed. Dissection of tissue was possible for all pathological conditions, and pressures between 3 and 45 bars were used. In gliomas, metastases, epilepsy surgery, and hemangioblastoma, the tissue was dissected at pressures between 3 and 17 bars, which preserved blood vessels. Dissection of meningiomas and the ICA stenosis required higher pressures (between 20 and 45 bars); with these pressures, blood vessels were also dissected.

Conclusions. These results indicate that the waterjet dissection procedure can be used intraoperatively without complications. This device appears to be particularly suitable for the dissection of highly vascularized gliomas or normal brain tissue, in which tissue dissection with sparing of blood vessels can be achieved. To prove that this is a useful addition to the neurosurgical armamentarium, reduction of blood loss or postoperative brain edema compared with conventional methods should be demonstrated in future studies.

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Joachim Oertel, Jürgen Piek, Jan-Uwe Müller, Silke Vogelgesang, Rolf Warzok and Robert Michael Gaab

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Joachim Oertel, Michael Robert Gaab, Dirk-Thomas Pillich, Henry W. S. Schroeder, Rolf Warzok and Jürgen Piek

Object. The waterjet method of dissection has been shown to enable the precise dissection of the parenchyma vessels while preserving blood in cadaveric pig brains. The waterjet device has also been applied clinically to treat various diseases and disorders without complications. Evidence still remains to be gathered as to how the instrument performs in reducing surgical trauma, intraoperative blood loss, and postsurgical brain edema. In the present study the authors investigate these parameters in a comparison between waterjet dissection and ultrasonic aspiration in the rabbit brain in vivo.

Methods. Thirty-one rabbits received identical bilateral frontal corticotomies, which were created using the waterjet device or an ultrasonic aspirator. The animals were killed 1, 3, or 7 days, or 6 weeks after surgery and their brains were processed for immunohistological analysis. Blood vessel preservation, intraoperative hemorrhage, postsurgical brain edema, and posttraumatic microglial and astoglial reactions were evaluated. Only in animals subjected to waterjet dissection were preserved vessels observed within the corticotomies. In addition, less intraoperative bleeding occurred in animals in which the waterjet was used. The microglial reaction was significantly reduced by waterjet dissection compared with ultrasonic aspiration; however, no difference in edema formation or astrocytic reactivity was observed.

Conclusions. These results demonstrate that waterjet dissection appears to be less traumatic than ultrasonic aspiration with respect to intraoperative hemorrhage and postoperative microglial reactivity in the rabbit model. Nevertheless, no difference in edema formation could be demonstrated. It remains to be proven that the observed differences are of clinical relevance.

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Henry W. S. Schroeder, Joachim Oertel and Michael R. Gaab

Object. Epidermoid tumors located in the cerebellopontine angle (CPA) are challenging lesions because they grow along the subarachnoid spaces around delicate neurovascular structures and often extend into the middle cranial fossa. The purpose of this study was to determine the value of endoscopic assistance in the microsurgical resection of these lesions, in which total removal is the therapy of choice.

Methods. Eight patients harboring an epidermoid tumor of the CPA were treated using an endoscope-assisted microsurgical technique. A retrosigmoid suboccipital approach was used in five patients and a pterional transsylvian approach was chosen in the other three. In four patients the lesion was resected microsurgically and the endoscope was used repeatedly to verify complete tumor removal, whereas most of the tumor mass was removed with the aid of an operating microscope in the other four. Tumor parts extending into other cranial compartments that were not visible through the microscope were removed under endoscopic view by using rigid rod-lens scopes with 30 and 70° angles of view.

All epidermoids were completely evacuated and the membranes were widely resected. Large tumors occupying both the middle and posterior cranial fossa were removed through a single small opening without enlarging the craniotomy. Permanent hearing loss and permanent hypacusis were observed in one patient each. One patient with facial and one with abducent nerve palsy recovered within 6 and 4 months, respectively. A transient weakness of the chewing muscles was encountered in one patient. Postoperative magnetic resonance imaging revealed no residual tumor in any patient. To date no recurrences have been observed (follow up range 12–98 months).

Conclusions. The endoscope-assisted microsurgical technique enables safe removal even when tumor parts are not visible in a straight line. Tumor extensions into adjacent cranial compartments can be removed with the same approach without retracting neurovascular structures or enlarging the craniotomy.

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Joachim Oertel, Ekaterina von Buttlar, Henry Werner Siegfried Schroeder and Michael Robert Gaab

The benefit of the current strategy for diagnosis (magnetic resonance [MR] imaging) and treatment (surgery, chemotherapy, radiotherapy) of gliomas, in contrast to the standard treatment in use before MR imaging and the micro-surgical era, has not yet been determined. A retrospective statistical analysis was performed for all patients with glioma who underwent surgery at a single institution between 1965 and 1974 (Group I, 88 patients) or 1986 and 1995 (Group II, 249 patients). There were no major differences in symptomatology, tumor localization, and number of surgical procedures. The mean time until tumor diagnosis was significantly shorter in Group II (Group I, 48 weeks; Group II, 19.5 weeks). Also, the mean time from initial symptoms to surgery was significantly shorter for high-grade gliomas in Group II (Group I, 16.3 weeks; Group II, 11.7 weeks). For high- as well as low-grade gliomas, there was a clear reduction of the perioperative morbidity and mortality rates in Group II. Nevertheless, for the postoperative duration of survival, no significant differences were demonstrated for high- or low-grade gliomas. Based on the results of this study, the perioperative morbidity and mortality rate as well as the time from diagnosis to treatment have been remarkably reduced within the last 30 years. Nevertheless, the overall prognosis for patients with gliomas has not changed from the 1970s until today. Thus, the introduction of modern diagnostic modalities and surgical procedures has not improved the outcome in patients with glioma. Further research to improve the treatment of this disease is urgently needed.

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Joachim Oertel, Michail Gen, Joachim K. Krauss, Matthias Zumkeller and Michael R. Gaab

✓Waterjet dissection enables vessel preservation and a reduction in intraoperative blood loss. Because even minimal bleeding should be avoided during neuroendoscopy, the waterjet device may be a particularly valuable tool in such procedures. The authors used this instrument in experimental endoscopic procedures in 20 cadaveric porcine brains and clinically in four patients with obstructive hydrocephalus. A precise and accurate septostomy was achieved in all of the pig brains. In two patients the hydrocephalus was due to intraventricular hemorrhage, in one a posterior fossa tumor, and in one a cystic craniopharyngioma. In all patients the surgical view was kept clear with waterjet irrigation and suction. Using a pressure setting of 10 bars, the waterjet device successfully perforated the cyst wall of the craniopharyngioma in one patient and the floor of the third ventricle in three patients. The use of the waterjet device in selected endoscopic procedures appears safe, and may help reduce intraoperative bleeding. However, further studies are needed to confirm the utility of the waterjet tool in endoscopy.

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Joachim Oertel, Joachim Kurt Krauss and Michael Robert Gaab

Neuroendoscopic techniques are often considered inapplicable to lesion resection because most lesions are too large for effective endoscopic resection in an appropriate time frame. To evaluate the potential of ultrasonic aspiration in neuroendoscopic procedures, the authors developed a new handpiece for endoscopic application. The instrument was subsequently tested in 10 cadaveric pig brains and applied in 5 clinical cases. In the pig brain, a precise and accurate aspiration of ventricular ependyma and brain parenchyma was obtained. Clinically, the device was applied in 3 patients with obstructive hydrocephalus, and via an endonasal transsphenoidal approach in 2 patients with pituitary macroadenomas. In all cases, the lesion was effectively aspirated without complications. Ultrasonic aspiration can be applied safely and successfully in selected endoscopic procedures. The use of this technique could expand the indications for endoscopic approaches to include intraventricular lesions and in minimally invasive transsphenoidal endonasal approaches.

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Joachim M. K. Oertel, Yvonne Mondorf and Michael R. Gaab

Obstructive hydrocephalus due to giant basilar artery (BA) aneurysm is a rare finding, and endoscopic treatment has not been reported. Here the authors present their experience with endoscopic third ventriculostomy (ETV) in obstructive hydrocephalus due to giant BA aneurysm. Between December 2000 and March 2007, 3 patients (2 men and 1 woman; age range 32–80 years) underwent an ETV for the treatment of obstructive hydrocephalus caused by a giant BA aneurysm. All 3 patients presented with cephalgia, nausea, vomiting, and a variable decrease in consciousness. An obstructive hydrocephalus caused by a giant BA aneurysm was found in each case as the underlying pathological entity. Intraoperatively, a narrowing of the third ventricle by upward displacement of the tegmentum was found in all 3 patients. A standard ETV was performed and included an inspection of the prepontine cisterns. The endoscopic treatment was successful in all patients with respect to clinical signs and radiological ventricular enlargement. No complications were observed. In all, the endoscopic ventriculostomy was proven to be a successful treatment option in obstructive hydrocephalus even if it is caused by untreated giant BA aneurysm.

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Joachim M. K. Oertel, Joerg Baldauf, Henry W. S. Schroeder and Michael R. Gaab

Object

There are frequent applications for endoscopy in neurosurgery. However, endoscopic surgery in children has peculiar characteristics and is associated with different rates of success. In this study, the authors report on their experience with 134 consecutive endoscopy procedures performed in 126 patients < 18 years of age.

Methods

Between April 1993 and October 2007, 134 endoscopic procedures were performed in 126 children. Indications for surgery included brain tumors in 48 children, cystic lesions in 24, aqueductal stenosis in 23, various malformations in 20, hemorrhage and infarction in 6, and isolated ventricles in 5 children. In this long-term followup study, data were analyzed with respect to clinical and radiological success rates, as well as shunt dependence both in relation to lesion origin, and to the type of endoscopic procedure performed (endoscopic third ventriculostomy [ETV], septostomy, aqueductoplasty, or cystocisternostomy). Finally, the influence of patient age on the success rate was evaluated.

Results

In 114 patients, restoration of CSF circulation was the goal of endoscopy, but in 2 patients only ventriculoscopy was performed followed by ventriculoperitoneal shunt placement. In 12 of 114 patients, tumor biopsy sampling or resection was performed simultaneously with shunt placement. In another 12 patients, only endoscopic tumor resection without CSF circulation restoration was done. The follow-up period ranged from 1 to 6 years. Thirteen tumor biopsies, 7 partial tumor resections, and 4 endoscopically complete tumor resections were performed. An intraoperative switch to microsurgery was made in 2 patients because of recurrent hemorrhage and an overly time-consuming endoscopic surgery. Cerebrospinal fluid circulation was successfully restored in 81 (72%) of 112 patients, with the use of endoscopy in the setting of tumor-related hydrocephalus providing the best results (86% success rate). However, of the various endoscopic procedures, cyst openings (cystocisternostomy, cystoventriculostomy, and ventriculocystocisternostomy) provided the best results—superior even to ETV—with a success rate of 77% and no complications. In contrast, endoscopic aqueductoplasty had a high failure and complication rate. Patients < 6 months old who underwent ETV, septostomy, or aqueductoplasty had poor results and became more frequently shunt dependent than older children.

Conclusions

Overall, endoscopy can be considered safe and effective in children. Based on the authors' data, acute hydrocephalus cases such as those caused by tumors are the best candidates for endoscopic CSF flow restoration. Interestingly, cyst openings to the ventricles or cisterns were the most successful endoscopic techniques with the lowest complication rate. Aqueductoplasty should be reserved for selected cases. Finally, the success rate of endoscopic techniques remains poor in infants < 6 months of age; this was not only true of ETV, but also other techniques such as septostomy and aqueductoplasty.

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Joachim M. K. Oertel, Jörg Baldauf, Henry W. S. Schroeder and Michael R. Gaab

Object

The optimal therapy of arachnoid cysts is controversial. In symptomatic extraventricular arachnoid cysts, fenestration into the basal cisterns is the gold standard. If this is not feasible, shunt placement is frequently performed although another endoscopic option is available.

Methods

Between March 1997 and June 2006, 12 endoscopic cystoventriculostomies were performed for the treatment of arachnoid cysts in 11 patients (4 male and 7 female patients, mean age 52 years [range 14–71 years]). All patients were prospectively followed up.

Results

In 11 cases, the arachnoid cysts were frontotemporoparietal and fenestration was performed into the lateral ventricle. In 1 case, the arachnoid cyst was located in the cerebellum and the cyst was fenestrated into the fourth ventricle. Neuronavigational guidance was used in all but 1 case. Endoscopic cystoventriculostomy was performed in all cases without complications. No stents were placed. The mean surgical time was 71 minutes (range 30–110 minutes). The mean follow-up period was 42.7 months (range 19–96 months) per surgical case and 48.8 months (range 19–127 months) per patient. Symptoms improved after 11 of the 12 procedures; 7 of the 11 patients became symptom-free and the others had only mild residual symptoms. The patient who did not experience clinical improvement suffered from depression and demonstrated a significant decrease of the cyst size on the postoperative MR imaging. After 11 of 12 procedures, a decrease in cyst size was observed. In 1 case, a subdural hematoma developed; it required surgical treatment 3 months after surgery. In another case, reclosure of the stoma required repeated endoscopic cystoventriculostomy more than 7 years after the initial procedure.

Conclusions

Overall, endoscopic cystoventriculostomy represents a useful treatment option for patients with paraxial arachnoid cysts in whom a standard cystocisternotomy is not feasible. Based on the results in this case series, stent placement appears not to be required. Despite the long mean follow-up of almost 4 years, however, a longer follow-up period seems to be required before definite conclusions can be drawn.