Long-Term Reliability of Neuroendoscopic Aqueductoplasty in Idiopathic Aqueductal Stenosis-Related Hydrocephalus.

BACKGROUND: During the 1990s, endoscopic aqueductoplasty (AP) was considered to be a valuable alternative to endoscopic third ventriculostomy (ETV) in treating hydrocephalus related to idiopathic aqueductal stenosis (iAS), with promising short-term outcomes. OBJECTIVE: To evaluate the long-term outcome of AP in the treatment of iAS. METHODS: Long-term follow-up clinical examinations and magnetic resonance (MR) imaging were performed for patients treated by an AP for iAS in our department. RESULTS: Twenty patients (14 female, 6 male, mean age 41.7 yr, range 0.5-67 yr) were treated between 1996 and 2002. Two patients were lost to long-term follow-up. One patient died 6 mo after AP, but death was not related to the procedure. The mean follow-up for the remaining 17 patients was 120 mo. Clinically relevant aqueductal reclosure was observed in 11/17 patients after a mean follow-up of 53.4 mo. These 11 patients underwent ETV, which has been successful during further follow-up. Four of the six remaining patients presented with no clinical symptoms, although aqueductal restenosis was observed on MR imaging. Thus, the overall failure rate of AP was 88.2%. The failures were homogeneously distributed over the entire follow-up period. CONCLUSION: AP has a high risk of failure during long-term follow-up and is not recommended as the first choice of treatment in hydrocephalus caused by iAS. ETV should be done instead. AP may be reserved for a limited number of patients in whom ETV is not feasible but should be combined with stenting to avoid reclosure of the aqueduct.

Long-Term Results After Endoscopic Resection of Colloid Cysts.

BACKGROUND: Endoscopic resection of colloid cysts is a widely accepted treatment option instead of microsurgery. However, there is still a debate about a potentially higher rate of incomplete resections and recurrence. OBJECTIVE: The aim of this retrospective study was to evaluate long-term results after endoscopic removal of colloid cysts. METHODS: Twenty patients underwent endoscopic treatment in our department. Eighteen patients agreed to follow-up examinations. In 17 patients, magnetic resonance images were obtained. RESULTS: Total cyst resection was achieved in 16 procedures. In 1 patient, only plexus coagulation and widening of the ipsilateral foramen of Monro were performed. In 3 patients, small remnants of the cyst membrane were left behind. Conversion to microsurgery became necessary in 1 patient. Mild temporary complications occurred in 6 patients. Preoperative symptoms were completely relieved in 16 patients and improved in 2 patients. The average follow-up period was 188 months. In the patient with plexus coagulation, the cyst did not change. Recurrence occurred in 2 of 3 patients with cyst remnants. To date, no cyst remnant or recurrence has caused any symptoms or required surgical treatment. CONCLUSIONS: Our results indicate that endoscopic treatment of colloid cysts is a safe and effective treatment option that provides excellent long-term results. However, we determined that a significant risk for recurrence exists when even small parts of the cyst capsule were left behind. Therefore, we advocate an attempt at total endoscopic cyst resection.

Endoscopic Third Ventriculostomy before Posterior Fossa Tumor Surgery in Adult Patients.

OBJECTIVE: Obstructive hydrocephalus in patients with posterior fossa tumors is frequently seen. Treatment options include immediate tumor removal or prior cerebrospinal fluid (CSF) diversion procedures. The necessity and feasibility of an ETV in these situations has not yet been proven in adult patients. METHODS: We retrospectively reviewed our prospectively maintained database for ETVs before surgery of posterior fossa tumors in adults. The primary focus of data analyses was the question of whether the ETV was suitable to treat the acute situation of hydrocephalus without an increased rate of complications due to the special anatomical situation with a posterior fossa tumor. We also analyzed whether any further CSF diverting procedures were necessary. RESULTS: A total of 40 adult patients who underwent an ETV before posterior fossa tumor surgery were analyzed. Overall, 33 patients (82.5%) had clinical signs of hydrocephalus, and all of them improved in their clinical course after ETV. Seven patients (17.5%) did not demonstrate clinical signs of hydrocephalus, but ETV was performed with prophylactic or palliative intent in six patients and one patient, respectively. No complications were observed due to ETV itself. No permanent shunting procedure was necessary in a mean follow-up of 76.5 months. Early additional CSF diverting procedures (redo ETV, external ventricular drain) were performed in five patients (12.5%). CONCLUSION: The present series confirms the feasibility and safety of ETV before posterior fossa tumor surgery in adult patients. If patients had symptomatic hydrocephalus before tumor surgery, an ETV can be performed, followed by early elective tumor surgery. A prophylactic ETV in asymptomatic patients is not advised. Early elective tumor surgery should be performed in these patients.

The endoscopic endonasal transsphenoidal approach to sellar lesions allows a high radicality: The benefit of angled optics.

OBJECTIVE: The endonasal endoscopic approach is currently under investigation for perisellar tumour surgery. A higher resection rate is to be expected, and nasal complications should be minimized. Here, the authors report their technique of transnasal endoscopic neurosurgery with a special reference to the impact of the use of angled optics. MATERIAL AND METHODS: Two-hundred-and-seventy-one endoscopic endonasal transsphenoidal procedures were performed for sellar lesions between January 2000 and August 2013. One-hundred-and-twenty-nine patients out of them could be used for analysing the use of angled endoscopes including completed follow up, MR imaging as resection control and documentation of the intraoperative use and benefit of angled optics. Exclusion criteria were: planned incomplete resection or incomplete data set. The surgical technique was carefully analysed; and these cases were followed prospectively. RESULTS: Standard technique was a mononostril approach with 0° endoscopes. Angled endoscopes were used for assessment of radicality during the tumour resection and at the end of the procedure. In 95 cases (72%), an angled endoscope was used. Remnant tumour was visualized with angled optics in 27 of the 95 cases (28%). In all these cases, remnant tumour tissue was subsequently further removed. Complete resection was seen on MRI FU in 91 of 95 cases (96%) in this subgroup. In the cases without application of angled optics, there was already a sufficient sight via the 0° endoscope (14/34; 42%), or a significant bleeding from the cavernous sinus made the application of an angled endoscope impossible (19/34; 55%). On follow up, MRI revealed radical tumour resection in 93% (120/129). In the subgroup without angled optics use, radicality reached 88% (30/34) in contrast to 96% in the angled optics subgroup. Recurrent tumour growth was observed in four patients (3%). CONCLUSIONS: The endscopic technique has been shown to be safe and successful with a high radicality and only minor complications. The application of various angled endoscopes allows a look "around the corner" resulting in a potentially higher radicality of tumour resection in endonasal transsphenoidal surgery.

Neuroendoscopic stent placement for cerebrospinal fluid pathway obstructions in adults.

OBJECTIVE Since its revival in the early 1990s, neuroendoscopy has become an integral component of modern neurosurgery. Endoscopic stent placement for treatment of CSF pathway obstruction is a rarely used and underestimated procedure. The authors present the first series of neuroendoscopic intracranial stenting for CSF pathway obstruction in adults with associated results and complications spanning a long-term follow-up of 20 years. METHODS The authors retrospectively reviewed a prospectively maintained clinical database for endoscopic stent placement performed in adults between 1993 and 2013. RESULTS Of 526 endoscopic intraventricular procedures, stents were placed for treatment of CSF disorders in 25 cases (4.8%). The technique was used in the management of arachnoid cysts (ACs; n = 8), tumor-related CSF disorders (n = 13), and hydrocephalus due to stenosis of the foramen of Monro (n = 2) or aqueduct (n = 2). The mean follow-up was 87.1 months. No deaths or infections occurred that were related to endoscopic placement of intracranial stents. Late stent dislocation or migration was observed in 3 patients (12%). CONCLUSIONS Endoscopic intracranial stent placement in adults is rarely required but is a safe and helpful technique in select cases. It is indicated when reliable and long-lasting restoration of CSF pathway obstructions cannot be achieved with standard endoscopic techniques. In the treatment of tumor-related hydrocephalus, it is a good option to avoid reclosure of the restored CSF pathway by tumor growth. Currently, routine stent placement after endoscopic fenestration of ACs is not recommended. Stent placement for treatment of CSF disorders due to tumor is a good option for avoiding CSF shunting. To avoid stent migration and dislocation, and to allow for easy removal if needed, the device should be fixed to a bur hole reservoir.

Endoscopic Biopsy for Intra- and Paraventricular Tumors: Rates of Complications, Mortality, and Tumor Cell Dissemination.

BACKGROUND AND STUDY AIM: Intra- and paraventricular tumors are frequently associated with cerebrospinal fluid (CSF) pathway obstruction. Thus the aim of an endoscopic approach is to restore patency of the CSF pathways and to obtain a tumor biopsy. Because endoscopic tumor biopsy may increase tumor cell dissemination, this study sought to evaluate this risk. PATIENTS, MATERIALS, AND METHODS: Forty-four patients who underwent endoscopic biopsies for ventricular or paraventricular tumors between 1993 and 2011 were included in the study. Charts and images were reviewed retrospectively to evaluate rates of adverse events, mortality, and tumor cell dissemination. Adverse events, mortality, and tumor cell dissemination were evaluated. RESULTS: Postoperative clinical condition improved in 63.0% of patients, remained stable in 30.4%, and worsened in 6.6%. One patient (2.2%) had a postoperative thalamic stroke leading to hemiparesis and hemineglect. No procedure-related deaths occurred. Postoperative tumor cell dissemination was observed in 14.3% of patients available for follow-up. CONCLUSIONS: For patients presenting with occlusive hydrocephalus due to tumors in or adjacent to the ventricular system, endoscopic CSF diversion is the procedure of first choice. Tumor biopsy in the current study did not affect safety or efficacy.

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

OBJECTIVE: The endonasal endoscopic approach to skull base is still under investigation. The main goal is the minimal invasive approach to pathologies with a better rate of resection without retraction of the brain tissue. Here, the authors report their technique of transnasal endoscopic neurosurgery using a mononostril approach and its development. METHODS: The supplementary video demonstrates the different steps of the mononostril approach and resection of a pituitary adenoma. All video-recorded procedures that were carried out between 2000 and 2013 using this technique were analysed. The patients were followed prospectively. RESULTS: Visualization and handling were good in 246/251 (98%). In three cases, we had to switch to microscopy because of severe bleeding of the cavernous sinus. On follow-up, magnetic resonance imaging revealed radical tumour resection in 92% of all cases when intended. There was no mortality, and the low complication rate was remarkable. CONCLUSION: Our mononostril approach of transnasal transsphenoidal surgery shows better results compared with previously published reports in regards to radicality, low cerebrospinal fluid leaks and morbidity. The very low rate of nasal complains is particularly remarkable.

Endoscopic third ventriculostomy: preoperative considerations and intraoperative strategy based on 300 procedures.

PURPOSE: Although successful endoscopic third ventriculostomy (ETV) has been reported for many indications, peculiarities of the surgical technique in each separate indication require particular respect. METHODS: A detailed account of the authors' surgical technique, their presurgical considerations, and their intraoperative strategies to perform ETV is presented. Surgery of representative obstructive hydrocephalus cases in posterior fossa lesions (cerebellar infarction, posterior fossa tumor), in distortion of the ventricular system (intracranial hemorrhage, basilar artery aneurysm) and in membranous obstruction (aqueductal stenosis, posterior fossa malformation), is illustrated in detail. RESULTS: In posterior fossa lesions, careful evaluation of the prepontine space and localization of the basilar artery is mandatory. Recognition of mammillary bodies and infundibular recess is of particular importance since the third ventricle floor is rather thick and nontranslucent. In distortion of the ventricular system, careful analysis of the preoperative imaging allows the selection of the optimal approach. Sometimes, blood clot removal and vigorous irrigation is required. Frequently, the landmarks are difficult to identify. These are cases for experienced endoscopic neurosurgeons. In aqueductal stenosis and posterior fossa malformation, perforation of the often thin and translucent ventricular floor is easy because of clear anatomical landmarks. Those are ideal candidates for ETV. For experienced neuroendoscopists, the authors advocate inspection of the fourth ventricle with a flexible scope to ensure cerebrospinal fluid (CSF) circulation obstruction. CONCLUSIONS: ETV is a frequent and well-established endoscopic technique. Based on the underlying pathology, the technique has to be modified to obtain good results with minimal complications.

Endoscopic temporal ventriculocisternostomy: an option for the treatment of trapped temporal horns.

Entrapment of the temporal horn is a rare form of isolated hydrocephalus. Standard treatment has not yet been established for this condition, and only a few cases have been reported in the literature. The authors reviewed their prospectively maintained database to report their experience with endoscopic temporal ventriculocisternostomy. All endoscopic operations performed in the Department of Neurosurgery at Ernst Moritz Arndt University between March 1993 and August 2012 were reviewed, and a retrospective chart review of all patients with temporal ventriculocisternostomy was performed. Four patients were identified (3 children and 1 adult). In 3 patients, the condition developed after tumor resection, and in 1 patient it developed due to postmeningitic multiloculated hydrocephalus. In 2 patients, a recurrent trapped temporal horn developed. Refenestration was successful in one of these patients, and dilation in the trigone area with a subsequent stomy of the septum pellucidum was successful in the other. In 1 patient, postoperative meningitis developed, which was treated with antibiotics. Endoscopic temporal ventriculocisternostomy is an option in the treatment of trapped temporal horns. However, more experience is required to recommend it as the treatment of choice.

Instrumentation: endoscopes and equipment.

OBJECTIVE: The technology and instrumentation for neuroendoscopy are described: endoscopes (principles, designs, applications), light sources, instruments, accessories, holders, and navigation. Procedures for cleaning, sterilizing, and storing are included. METHODS: The description is based on the author's own technical development and neuroendoscopic experience, published technology and devices, and publications on endoscopic surgery. RESULTS: The main work horses in neuroendoscopy are rigid glass rod endoscopes (Hopkins optics) due to the optical quality, which allows full high-definition video imaging, different angles of view, and autoclavability, which is especially important in neuroendoscopy due to the risk of Creutzfeldt-Jakob disease infection. Applications are endoscopy assistance to microsurgery, stand-alone endoscopy controlled approaches such as transnasal skull base, ventriculoscopy, and cystoscopy in the cranium. Rigid glass rod optics are also applicable in spinal endoscopy and peripheral nerve decompression using special tubes and cannulas. Rigid minifiberoptics with less resolution may be used in less complex procedures (ventriculoscopy, cystoscopy, endoscopy assistance with pen-designs) and have the advantages of smaller diameters and disposable designs. Flexible fiberoptics are usually used in combination with rigid scopes and can be steered, e.g. through the ventricles, in spinal procedures for indications including syringomyelia and multicystic hydrocephalus. Upcoming flexible chip endoscopes ("chip-in-the-tip") may replace flexible fiberoptics in the future, offering higher resolution and cold LED-illumination, and may provide for stereoscopic neuroendoscopy. Various instruments (mechanical, coagulation, laser guides, ultrasonic aspirators) and holders are available. Certified methods for cleaning and sterilization, with special requirements in neuroapplications, are important. CONCLUSIONS: Neuroendoscopic instrumentation is now an established technique in neurosurgical practice and is experiencing rapid development (stereoscopy, integrated operating room).

Why does endoscopic aqueductoplasty fail so frequently? Analysis of cerebrospinal fluid flow after endoscopic third ventriculostomy and aqueductoplasty using cine phase-contrast magnetic resonance imaging.

OBJECT: The aim of this study was to evaluate and compare CSF flow after endoscopic third ventriculostomy (ETV) and endoscopic aqueductoplasty (EAP) in patients presenting with obstructive hydrocephalus caused by aqueductal stenosis. METHODS: In patients harboring aqueductal stenosis who underwent EAP (n=8), ETV (n=8), and both ETV and EAP (n=6), CSF flow through the restored aqueduct and through the ventriculostomy was investigated using cine cardiac-gated phase-contrast MRI. For qualitative evaluation of CSF flow, an in-plane phase-contrast sequence in the midsagittal plane was used. The MR images were displayed in a closed-loop cine format. Quantitative through-plane measurements were performed in the axial plane perpendicular to the aqueduct and/or floor of the third ventricle. RESULTS: Evaluation revealed significantly higher CSF flow through the ventriculostomies compared with flow through the aqueducts. This was true both when comparing the ETV group with the EAP group and when comparing the flow of the ventriculostomy and aqueduct within the ETV and EAP group. There was no difference in aqueductal CSF flow between patients who underwent EAP alone and patients who underwent ETV and EAP. There was also no difference in ventriculostomy CSF flow between patients who underwent ETV alone and patients who underwent ETV and EAP. Fifty percent of the restored aqueducts became occluded at a mean of 46 months after surgery (range 18-126 months). In contrast, all ETVs remained patent in the mean follow-up period of 110 months after surgery, although 1 patient required shunt placement after 66 months. CONCLUSIONS: Cerebrospinal fluid flow through ventriculostomies is significantly higher than aqueductal CSF flow after EAP. This could be one factor to explain why the reclosure rate of aqueducts after EAP is higher than the reclosure rate of the ventriculostoma after ETV.

Water jet dissection in neurosurgery: an update after 208 procedures with special reference to surgical technique and complications.

BACKGROUND: Water jet dissection represents a promising technique for precise brain tissue dissection with preservation of blood vessels. In the past, the water jet dissector has been used for various pathologies. A detailed report of the surgical technique is lacking. OBJECTIVE: The authors present their results after 208 procedures with a special focus on surgical technique, intraoperative suitability, advantages, and disadvantages. METHODS: Between March 1997 and April 2009, 208 patients with various intracranial neurosurgical pathologies were operated on with the water jet dissector. Handling of the device and its usefulness and extent of application were assessed. The pressures encountered, potential risks, and complications were documented. The patients were followed 1 to 24 months postoperatively. RESULTS: A detailed presentation of the surgical technique is given. Differences and limitations of the water jet dissection device in the various pathologies were evaluated. The water jet dissector was intensively used in 127 procedures (61.1%), intermittently used in 56 procedures (26.9%), and scarcely used in 25 procedures (12%). The device was considered to be very helpful in 166 procedures (79.8%) and helpful to some extent in 33 procedures (15.9%). In 8 (3.8%) procedures, it was not helpful, and in 1 procedure (0.5%), the usefulness was not documented by the surgeon. CONCLUSION: The water jet dissector can be applied easily and very safely. Precise tissue dissection with preservation of blood vessels and no greater risk of complications are possible. However, the clinical consequences of the described qualities need to be demonstrated in a randomized clinical trial.

Waterjet dissection of peripheral nerves: an experimental study of the sciatic nerve of rats.

BACKGROUND: Although waterjet dissection has been well evaluated in intracranial pathologies, little is known of its qualities in peripheral nerve surgery. Theoretically, the precise dissection qualities could support the separation of nerves from adjacent tissues and improve the preservation of nerve integrity in peripheral nerve surgery. OBJECTIVE: To evaluate the potential of the new waterjet dissector in peripheral nerve surgery. METHODS: Waterjet dissection with pressures of 20 to 80 bar was applied on the sciatic nerves of 101 rats. The effect of waterjet dissection on the sciatic nerve was evaluated by clinical tests, neurophysiological examinations, and histopathological studies up to 12 weeks after surgery. RESULTS: With waterjet pressures up to 30 bar, the sciatic nerve was preserved in its integrity in all cases. Functional damaging was observed at pressures of 40 bar and higher. However, all but 1 rat in the 80 bar subgroup showed complete functional regeneration at 12 weeks after surgery. Histopathologically, small water bubbles were observed around the nerves. At 40 bar and higher, the sciatic nerves showed signs of direct nerve injury. However, all these animals showed nerve regeneration after 12 weeks, as demonstrated by histological studies. CONCLUSION: Sciatic nerves were preserved functionally and morphologically at pressures up to 30 bar. Between 40 and 80 bar, reliable functional and morphological nerve regeneration occurred. Waterjet pressures up to 30 bar might be applied safely under clinical conditions. This technique might be well suited to separate intact peripheral nerves from adjacent tumor or scar tissue. Further studies will have to show the clinical relevance of these dissection qualities.