Edward Baert

Endoscopic coagulation of choroid plexus hyperplasia

Hydrocephalus is a clinical disorder resulting from an imbalance between the production of CSF and its resorption, of which the latter is mostly a disadvantage. In rare cases of choroid plexus papilloma or carcinoma, hydrocephalus is due to an overproduction of CSF. Choroid plexus hyperplasia (CPH) is a distinct clinicopathological entity in which the enlarged choroid plexus produces large amounts of CSF. Historically, patients with CPH were treated by shunt procedures or by microsurgical removal of the choroid plexus, which is associated with a high complication rate. In this paper the authors show that endoscopic plexus coagulation can result in restoring the equilibrium of the intracranial fluid volumes, resulting in shunt independency. In this way, both the shunt-related complications and the bleeding risks of microsurgical plexectomy are avoided. In instances of hydrocephalus, thorough efforts should be made to demonstrate the underlying pathophysiology to choose the optimal treatment, of which shunt procedures should receive the least priority.

Endoscopic Treatment of Temporal Arachnoid Cysts in 34 Patients

INTRODUCTION Arachnoid cysts are lesions present in 1% of the population and usually found in the temporal fossa. Clinical and radiologic presentations can differ greatly. Despite intensive research, it is still debatable which patients will benefit from surgery. OBJECTIVE This study aims to investigate the pretreatment parameters influencing the outcome after neuroendoscopic treatment of temporal arachnoid cysts. MATERIALS AND METHODS A retrospective analysis of 34 patients who underwent an endoscopic fenestration of a temporal arachnoid cyst between July 1991 and December 2013 was performed. RESULTS In symptomatic patients, there was a clinical improvement in 76.4% of cases. The best results were found in treating symptoms related to intracranial hypertension, acute neurologic defects, and macrocrania. Patients with temporal lobe epilepsy improved after cyst fenestration in 33.3% of cases. Behavioral problems and psychomotor retardation remained largely unchanged. Patients with a complex neurologic presentation, often from a congenital syndrome and combined with an intellectual disability, had the least benefit from endoscopic surgery. Radiologic follow-up showed a cyst volume decrease in 91.2% of cases. Complications were present in 29.4%, but were mostly minor and transient. CONCLUSION This study demonstrates that patients with symptoms related to intracranial hypertension, acute neurologic deficits, and macrocrania have the best postoperative outcome. Also, patients with ipsilateral temporal lobe epilepsy seem to be good candidates for endoscopic arachnoid cyst fenestrations. In complex neurologic disorders without one of the previously mentioned symptoms, endoscopy remains less successful.

Treatment of cystic craniopharyngioma by endocavitary instillation of yttrium⁹⁰ radioisotope--still a valuable treatment option.

Craniopharyngiomas are a challenging pathology in neurosurgery because of their anatomic localization in the (supra)sellar region and their contact with diencephalic structures around the third ventricle. Among the different treatment modalities, stereotactic intracavitary treatment by instillation of yttrium⁹⁰ radioisotope is a minimally invasive technique of particular use in the treatment of cystic or partially cystic craniopharyngiomas. It can be performed under local anesthesia during a short hospitalization and has a long-lasting effect. This treatment can be repeated or used in combination with other treatment modalities such as microsurgery, endoscopy, conformal external radiation therapy, or stereotactic radiosurgery. Thus, this old and perhaps almost forgotten treatment option is still valuable in the treatment of cystic craniopharyngiomas.

Treating Hydrocephalus with Retrograde Ventriculosinus Shunt: Prospective Clinical Study

BACKGROUND Since the 1950s, hydrocephalus has been be treated with cerebrospinal fluid (CSF) shunts, usually to the peritoneal cavity or to the right cardiac atrium. However, because of their siphoning effect, these shunts lead to nonphysiologic CSF drainage, with possible comorbidity and high revision rates. More sophisticated shunt valve systems significantly increase costs and technical complexity and remain unsuccessful in a subgroup of patients. In an attempt to obtain physiologic CSF shunting, many neurosurgical pioneers shunted towards the dural sinuses, taking advantage of the physiologic antisiphoning effect of the internal jugular veins. Despite several promising reports, the ventriculosinus shunts have not yet become standard neurosurgical practice. METHODS In this single-center prospective clinical study, we implanted the retrograde ventriculosinus shunt, as advocated by El-Shafei, in 10 patients. This article reports on our operation technique and long-term outcome, including 4 patients in whom this shunt was implanted as a rescue operation. RESULTS Implantation of a ventriculosinus shunt proved to be feasible, warranting physiologic drainage of CSF. However, in only 3 of 14 patients, functionality of the retrograde ventriculosinus shunt was maintained during more than 6 years of follow-up. In our opinion, these shunts fail because present venous access devices are difficult to implant correctly and become too easily obstructed. After discussion of possible causes of this frequent obstruction, a new dural venous sinus access device is presented. CONCLUSION An easy-to-implant and thrombogenic-resistant dural venous sinus access device needs to be developed before ventriculosinus shunting can become general practice.

A non-hydrocephalic goat experimental model to evaluate a ventriculosinus shunt:

The ventriculosinus shunt is a promising treatment for hydrocephalus. Currently, different shunt techniques exist, and it is not clear whether one is preferable. This pilot study reports on a non-hydrocephalic goat model (Saanen breed) that provides opportunities to evaluate and optimize several aspects of the ventriculosinus shunt technique. Analysis of the coagulation properties of 14 goats by a viscoelastic coagulation monitor showed that goats have a hypercoagulable state compared to humans. This property can be partially counteracted by antiplatelet drugs. During implantation of a ventriculosinus shunt, a pulsatile reflux of blood was observed. After implantation, the animals recovered to their preoperative state, and none of them developed a superior sagittal sinus thrombosis. Evaluation of the shunts after 16 days showed an obstructing luminal clot. Several model-related factors may have promoted this obstruction: the absence of hydrocephalus, the hypercoagulability of caprine blood and the smaller dimensions of the caprine superior sagittal sinus. However, the pulsatile reflux of blood, which is caused by the compliance of the shunt system distal to the valve, may have been an important factor as well. In conclusion, the non-hydrocephalic goat model limits animal suffering and simplifies the study protocol. This model allows researchers to evaluate their implantation technique and shunt hardware but not the efficacy of the treatment or shunt survival.

Intracranial complications of midline nasal dermoid cysts

Abstract Background: Nasal dermoid cysts are common tumors in children. Due to anomalies in embryologic development of the nasal complex, sometimes an intracranial extension exists. When these cysts become infected they can lead to meningitis, brain abscess and death. Methods: We report the case of a 1.5-year-old girl admitted to the paediatric intensive care unit after infection of a nasal dermoid cyst. Results: The infant had a spiking fever and epileptic seizures. She was stabilized, intubated and a CT scan showed a subcutaneous mass with an adjacent zone of encephalitis and brain abscess formation. Neurosurgical interventions were necessary to lower intracranial pressure and control infectious spread. After a hospital stay of 69 days the child could be discharged. Due to her young age, irreversible brain damage is expected. Conclusion: Nasal midline dermoid cysts are considered benign swellings. When an intracranial extension exists, infection can lead to deleterious complications. It is important for health care practitioners to be aware of this imminent risk. Suspicion of a nasal midline dermoid cyst should prompt a careful clinical work-up with an ultrasound followed by CT or MRI imaging. The treatment is complete excision to avoid disastrous complications and recurrences.

The use of the trendelenburg position in the surgical treatment of extreme cerebellar slump

Background. State-of-the-art treatment for Chiari Malformation I (CM-I) consists of decompression by posterior fossa craniectomy. A rare but severe complication that develops over months to years after this procedure is cerebellar slump. Treatment options for this condition are limited. We present a new and promising approach to treat this rare condition. Methods. The patients were placed in the Trendelenburg position to facilitate ascent of the cerebellum. After almost complete dissolution of neurologic symptoms, surgical reconstruction was performed by tonsillar resection and the creation of a new structural support using a bone graft. Results. Both patients experienced good clinical and morphological outcomes immediately after surgery, and for two years thereafter. Conclusions. Neurological symptoms related to cerebellar or brainstem slump can be adequately reversed by placing the patient in the Trendelenburg position. After uneventful gravitational reversal of the slump, safe surgical reconstruction of the cerebellar support can be performed to securely preserve the anatomical reversal.

A Novel Design for Steerable Instruments Based on Laser-Cut Nitinol

Objective. Omnidirectional articulated instruments enhance dexterity. In neurosurgery, for example, the simultaneous use of 2 instruments through the same endoscopic shaft remains a difficult feat. It is, however, very challenging to manufacture steerable instruments of the requisite small diameter. We present a new technique to produce such instruments by means of laser cutting. Only 3 coaxial tubes are used. The middle tube has a cutting pattern that allows the steering forces to be transmitted from the proximal to the distal end. In this way the steering part is concealed in the wall of the tube. Large diameter articulated instruments such as for laparoscopy might benefit from the excellent tip stability provided by the same economical technology. Method. Coaxial nitinol tubes are laser-cut with a Rofin Stent Cutter in a specific pattern. The 3 tubes are assembled by sliding them over one another, forming a single composite tube. In a surgical simulator, the neurosurgical microinstruments and laparoscopic needle drivers were evaluated on surgical convenience. Results. Simultaneous use of 2 neurosurgical instruments (1.5 mm diameter) through the same endoscopic shaft proved to be very intuitive. The tip of the steerable laparoscopic instruments (10 mm diameter) could resist a lateral force of more than 20 N. The angle of motion for either instrument was at least 70° in any direction. Conclusions. A new design for steerable endoscopic instruments is presented. It allows the construction in a range from microinstruments to 10-mm laparoscopic devices with excellent tip stability.

Three dimensional methylacrylate and wax skull modeling preparing cranioplasty in the treatment of complex craniosynostosis and skull malformation

Objective: Complex craniosynostosis (e.g. coronal plagiocephaly, trigonocephaly, multisuture synostosis or skull malformation of unknown etiology) requires complex and prolonged cranioplastic procedures with a high risk of comorbidity (blood loss, temperature decrease, cerebrospinal fluid leak, air embolism…) while most of the treated patients are still infants. Also, the cosmetic results are not always as expected: As evaluation during surgery is time consuming and difficult to obtain, one often remains uncertain determining where to saw, how far to mobilise, how to rotate and how to fix the bone flaps. Certainly in cases of coronal plagiocephaly, when one has to decide how far to advance and how to incline the orbital rim, preoperative planning could be of valuable help. Therefore, we decided to realise three-dimensional skull models in dental wax, enabling us to prepare surgery. Methods: With 1 mm thick and contiguously sliced CT scan of the skull in bone windowing, three-dimensional skull models were created in methylacrylate bij Materialise, a corporation at Leuven, Belgium. At our department, by using negative casts in silicone, various copies of these methylacrylate models were produced in dental wax. These wax models proved anatomically exact and were easy and cheap to manufacture. They were extremely useful in preparing surgery as we could easily cut “bone flaps” with heated knives. These “bone flaps” could be bent, broken, rotated and fixed as in real surgery. However, realising these wax models was time consuming (in the range of 5 hours in a period of 2 days). Results: From March 2005 up to now, we performed cranioplasty on 7 patients with the help of three-dimensional skull modelling. Two patients suffered from unilateral coronal plagiocephaly, (5m old male, 5m old female), one from multisuture craniosynostosis (6m old male with Apert’s syndrom), three from trigonocephaly (5m old male, 8m old male, 6y old male) and one from a malformation in the maxillofrontotemporonasal region of unknown etiology (17y old male). Surgery was performed in a faster and more confident way on those 7 patients. None of the patients suffered from complications related to surgery. Apart from postoperative respiratory infection problems, no significant postop morbidity was encountered. None of these patients needed to be reoperated. We are confident that surgical comorbidity was reduced and that cosmetic outcome improved significantly thanks to the preoperative planning on the wax models. Conclusions: In spite of the very limited number of patients and the time-consuming preparation, we consider preoperative three-dimensional skull modelling in dental wax as an affordable, reliable, very helpful tool, allowing a reduction in operative duration and therefore comorbidity and to significantly improve cosmetic outcome. We will continue this preoperative planning in cases of complex craniosynostosis.