Frederick A. Boop
John R.W. Kestle
Meharpal Sangra, Simon Clark, Caroline Hayhurst, and Conor Mallucci
Image-guided neuroendoscopy is being increasingly used in an attempt to reduce the morbidity associated with surgery and to make navigation easier. It has a particularly useful application in the pediatric population for the treatment of conditions such as complex hydrocephalus and arachnoid cysts. However, its use has been limited by the requirement for rigid head fixation, which may be difficult in infants because of the immaturity of the skull. In addition there can be line-of-sight issues, which can be a problem with optical-based systems. Electromagnetic navigation has eliminated the requirement for head immobilization, and its successful use in the infant population has been reported. The authors present their series to date, define its role, and discuss its advantages over other forms of image-guided navigation.
The authors used the electromagnetic StealthStation and software (Medtronic) for neuronavigation. A dynamic reference frame was attached to the head using an adhesive dressing. The patient was positioned without rigid fixation and was registered using a specially designed stylet. Navigation was through a stylet, which could be placed within the endoscope. Direct advantages were no rigid head fixation, the ability to maneuver the endoscope without the requirement for a bulky optical attachment, and no loss of navigation caused by user obstruction of reflective fiducial markers. The authors performed a total of 28 procedures in 23 patients. There were 9 arachnoid cyst marsupializations, 4 multiple fenestrations for multiloculated hydrocephalus, 4 aqueductal stenting procedures for encysted fourth ventricles, 5 endoscopic third ventriculostomies, 3 septum pellucidotomies, 2 tumor biopsies, and 1 tumor cyst decompression.
Electromagnetic navigation was successful in all cases. Two complications were reported: a subdural collection, requiring bur hole drainage after a successful fenestration of the arachnoid cyst and failed treatment of complex hydrocephalus requiring subsequent placement of a ventriculoperitoneal shunt.
The electromagnetic technology provides reliable image-guided endoscopy. It has several advantages over alternative forms of stereotaxy, and the ability to use it without the need for rigid head fixation makes it eminently suitable for the pediatric population. Its use and application in the treatment of a variety of different conditions has been demonstrated successfully.
Matthew G. Stovell, Rasheed Zakaria, Jonathan R. Ellenbogen, Mathew J. Gallagher, Michael D. Jenkinson, Caroline Hayhurst, and Conor L. Mallucci
Endoscopic third ventriculostomy (ETV) is an effective treatment for obstructive hydrocephalus and avoids the risk for foreign-body infection associated with ventriculoperitoneal (VP) shunts. The short-term failure rate of ETV strongly depends on the indications for its use but is generally thought to be lower in the long term than that of VP shunts. However, few studies are available with long-term follow-up data of ETV for hydrocephalus in children. The authors reviewed the long-term success of ETV at their institution to investigate the rate of any late failures of this procedure.
Between April 1998 and June 2006, 113 children (including neonates and children up to 16 years old) had primary or secondary ETV for different causes of hydrocephalus. The patients' medical records and the authors' electronic operation database were reviewed for evidence of additional surgery (i.e., repeat ETV or VP shunt insertion). These records were checked at both the pediatric and adult neurosurgical hospitals for those patients who had their care transferred to adult services.
The median length of follow-up was 8.25 years (range 1 month to 16 years). Long-term follow-up data for 96 patients were available, 47 (49%) of whom had additional ETV or VP shunt insertion for ETV failure. Twenty patients (21%) had a second procedure within 1 month, 17 patients (18%) between 1 and 12 months, 7 patients (7%) between 1 and 5 years, and 3 patients (3%) between 5 and 8 years.
In the authors' series, ETV had an initial early failure rate for the treatment of pediatric hydrocephalus as reported previously, and this rate significantly depended on patient age and hydrocephalus etiology. Once stabilized and effective, ETV appeared to be durable but not guaranteed, and some late decline in effectiveness was observed, with some ETV failures occurring many years later. Thus, successful ETV in children cannot be guaranteed for life, and some form of follow-up is recommended long term into adulthood.
Caroline Hayhurst, Jibril Osman-Farah, Kumar Das, and Conor Mallucci
The aim of this study was to evaluate the efficacy of endoscopic third ventriculostomy (ETV) in patients with Chiari malformation Type I (CM-I) and hydrocephalus with or without syringomyelia.
The authors identified, in a prospective endoscopy database, 16 adults and children (age range 2–68 years) with CM-I and hydrocephalus that had been managed with ETV. They reviewed the clinical features and radiographic findings for all patients. Fifteen patients underwent ETV as a primary treatment, whereas 1 patient underwent the procedure at the time of shunt failure. All patients had symptomatic hydrocephalus with either aqueductal or fourth ventricular outflow obstruction. The mean duration of follow-up was 42 months.
Fifteen patients (94%) remain shunt free following ETV for CM-I. Five (83%) of the 6 patients with a syrinx had improvement or resolution of the syrinx following ETV. Six patients (37.5%) underwent foramen magnum decompression for persistent CM-I– or syrinx-related symptoms. There was no cerebrospinal fluid leakage or intracranial pressure–related problem following foramen magnum decompression.
Endoscopic third ventriculostomy provides a durable method of treatment for hydrocephalus associated with CM-I. It is effective as a primary treatment, and the authors advocate its use as a replacement for routine ventriculoperitoneal shunt insertion in these patients. Management of the hydrocephalus alone is often sufficient and may obviate decompression, although a significant proportion of patients will still need both procedures.
Harishchandra Lalgudi Srinivasan, Mitchell T. Foster, Kirsten van Baarsen, Dawn Hennigan, Benedetta Pettorini, and Conor Mallucci
Children with posterior fossa tumors (PFTs) may present with hydrocephalus. Persistent (or new) hydrocephalus is common after PFT resection. Endoscopic third ventriculostomy (ETV) is sometimes performed prior to resection to 1) temporize hydrocephalus prior to resection and 2) prophylactically treat post-resection hydrocephalus. The objective of this study was to establish, in a historical cohort study of pediatric patients who underwent primary craniotomy for PFT resection, whether or not pre-resection ETV prevents the need for post-resection CSF diversion to manage hydrocephalus.
The authors interrogated their prospectively maintained surgical neuro-oncology database to find all primary PFT resections from a single tertiary pediatric neurosurgery unit. These data were reviewed and supplemented with data from case notes and radiological review. The modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) score was retrospectively calculated for all patients. The primary outcome was the need for any form of postoperative CSF diversion within 6 months of PFT resection (including ventriculoperitoneal shunting, ETV, external ventricular drainage [EVD], and lumbar drainage [LD]). This was considered an ETV failure in the ETV group. The secondary outcomes were time to CSF diversion, shunt dependence at 6 months, and complications of ETV. Statistical analysis was done in RStudio, with significance defined as p < 0.05.
A total of 95 patients were included in the study. There were 28 patients in the ETV group and 67 in the non-ETV group. Patients in the ETV group were younger (median age 5 vs 7 years, p = 0.04) and had more severe preoperative hydrocephalus (mean frontal-occipital horn ratio 0.45 vs 0.41 in the non-ETV group, p = 0.003) and higher mCPPRH scores (mean 4.42 vs 2.66, p < 0.001). The groups were similar in terms of sex and tumor histology. The overall rate of post-resection CSF diversion of any kind (shunt, repeat ETV, LD, or EVD) in the entire cohort was 25.26%. Post-resection CSF diversion was needed in 32% of patients in the ETV group and in 22% of the patients in the non-ETV group (p > 0.05). Shunt dependence at 6 months was seen in 21% of the ETV group and 16% of the non-ETV group (p > 0.05). The median time to ETV failure was 9 days. ETV failure correlated with patients with ependymoma (p = 0.02). Children who had ETV failure had higher mCPPRH scores than the ETV success group (5.67 vs 3.84, p = 0.04).
Pre-resection ETV did not reliably prevent the need for post-resection CSF diversion. ETV was more likely to fail in children with ependymoma and those with higher mCPPRH scores. Based on the findings of this study, the authors will change the practice at their institution; pre-resection ETV will now be performed based on a newly defined protocol.
Caroline Hayhurst, Patricia Byrne, Paul R. Eldridge, and Conor L. Mallucci
The authors investigated the practicality of electromagnetic neuronavigation in routine clinical use, and determined the applications for which it is at the advantage compared with other systems.
A magnetic field is generated encompassing the surgical volume. Devices containing miniaturized coils can be located within the field. The authors report on their experience in 150 cases performed with this technology.
Electromagnetic neuronavigation was performed in 44 endoscopies, 42 ventriculoperitoneal shunt insertions for slit ventricles, 21 routine shunt insertions, 6 complex shunt insertions, 14 external ventricular drain placements for traumatic brain injury, 5 awake craniotomies, 5 Ommaya reservoir placements, and for 13 other indications. Satisfactory positioning of ventricular catheters was achieved in all cases. No particular changes to the operating theater set-up were required, and no significant interference from ferromagnetic instruments was experienced. Neurophysiological monitoring was not affected, nor did it affect electromagnetic guidance.
Neuronavigation enables safe, accurate surgery, and may ultimately reduce complications and improve outcome. Electromagnetic technology allows frameless, pinless, image-guided surgery, and can be used in all procedures for which neuronavigation is appropriate. This technology was found to be particularly advantageous compared with other technologies in cases in which freedom of head movement was helpful. Electromagnetic neuronavigation was therefore well suited to CSF diversion procedures, awake craniotomies, and cases in which rigid head fixation was undesirable, such as in neonates. This technology extends the application of neuronavigation to routine shunt placement and ventricular catheter placement in patients with traumatic brain injury.
David G. Porter, Andrew J. Martin, Conor L. Mallucci, Catherine N. Makunura, and H. Ian Sabin
✓ The authors present the case of spinal cord compression in a 16-year-old boy due to the rare vascular lesion, Masson's vegetant hemangioendothelioma.
Caroline Hayhurst, Dawn Williams, Jawad Yousaf, David Richardson, Barry Pizer, and Conor Mallucci
Skull base tumors in children are rare but require complex approaches with potential morbidity to the developing craniofacial skeleton, in addition to tumor-related morbidity. Reports of long-term clinical and functional outcome following skull base approaches in children are scarce. The authors report long-term outcome in children with tumors undergoing multidisciplinary skull base surgery.
A retrospective analysis was undertaken of children undergoing surgery at a single institution between 1998 and 2008 for benign and malignant lesions of the anterior, middle, or posterior cranial base. Patients with craniopharyngioma, pituitary tumors, and optic glioma were excluded. Histology, surgical morbidity, length of hospital stay, progression-free survival, and adjuvant therapy were recorded. Functional and cognitive outcome was assessed prospectively using the Late Effects Severity Score (LESS).
Twenty-three children ranging in age from 13 months to 15 years underwent skull base approaches for resection of tumors during the study period. The median follow-up duration was 60 months. Tumor types included meningioma, schwannoma, rhabdomyosarcoma, neuroblastoma, angiofibroma, and chordoma. Complete resection was achieved in 12 patients (52%). Thirteen patients (57%) had benign histology. The median hospital stay was 7 days. There were 3 deaths, 1 perioperative and 2 from tumor progression. Two patients had CSF leakage (9%) and 2 developed meningitis. Two children (9%) had residual neurological deficit at last follow-up evaluation. Thirteen (59%) of 22 surviving patients received adjuvant therapy. The majority of the patients remain in mainstream education and 19 of the 20 surviving children have an LESS of 3 or lower.
Children tolerate complex skull base procedures well, with minimal surgical-related morbidity as well as good long-term tumor control rates and functional outcomes from maximal safe resection combined with adjuvant treatment when required.
Donncha F. O’Brien, Caroline Hayhurst, Barry Pizer, and Conor L. Mallucci
The primary aim of this study was to evaluate the success of endoscopic third ventriculostomy (ETV) as a treatment for obstructive hydrocephalus secondary to midline tumors (midbrain, pontine, pineal, tectal plate, thalamic, and third ventricular regions). In addition, the study examined the role and value of endoscopic tumor biopsy (ETB) in the management of such cases. All surgical procedures were performed through a single-trajectory approach.
A retrospective analysis of clinical notes, operation records, and pre- and postventriculostomy neuroimaging data was performed to determine the success or failure and complications of ETV and ETB in 42 patients presenting with tumor-induced obstructive hydrocephalus. Patient data were derived from an endoscopy database initiated in 1998. The study population included 21 female and 21 male patients (mean age 37 years, range 5–77 years). All 42 patients underwent an ETV; 33 of the 42 underwent an ETV and an ETB (single-trajectory). One patient was excluded from the follow-up analysis due to rapid deterioration of his condition from tumor progression. The duration of follow up ranged from 3 to 84 months (mean 32 months).
At the last follow up, 11 patients with ETVs had undergone shunt placement and two patients had undergone repeated ETVs, giving a long-term success rate of 68% (28 of 41 cases) for single ETV as a treatment for hydrocephalus at presentation. Statistical analysis revealed no significant relationship (p > 0.92) between tumor location and ETV success or failure. The mean time to ETV failure was 32 weeks. Histological examination of biopsy specimens was nondiagnostic in eight (24%) of the 33 cases in which ETB was performed. Seven of these cases involved pineal region tumors and one involved a tectal plate tumor. There was no death or major morbidity associated with ETV and ETB in this series.
Endoscopic third ventriculostomy is a safe and durable means of controlling hydrocephalus in tumor cases. Its success rate is high—comparable to that reported in aqueduct stenosis cases. Although ETB is probably not as accurate for diagnosis as biopsy with frame-based stereotactic guidance, it is associated with a lower mortality rate and, in the correct clinical setting, may be justifiably attempted as an initial biopsy procedure at the same time as ETV via a single-trajectory approach.