Complications of third ventriculostomy

As experience with ETV grows, the procedure will be performed by an increasing number of neurosurgeons. Although the technique has been greatly refined since its advent almost a century ago, today's neurosurgeon must never forget that this seemingly simple procedure holds the potential for a number of devastating complications. Appropriate training and experience are important to the success of ETV and for avoiding complications It is imperative that surgeons continue to report their experience with the complications of ETV so that the procedure can continue to be made as safe as possible.     

Techniques of endoscopic third ventriculostomy

Modem techniques of endoscopic third ventriculostomy (ETV) are based on the concept of establishing a natural conduit for cerebral spinal fluid (CSF) flow through the floor of the third ventricle. Through the years, a wide variety of techniques have been used as a means to this end and have included both open and closed approaches. However, the relatively recent application of endoscopic technology to intraventricular surgery has allowed neurosurgeons to perform third ventriculostomies in a minimally invasive fashion. Advances in third ventriculostomy technique have been based on a detailed understanding of third ventricular anatomy, surgical trajectories, and improved instrumentation. The goal of this article is to discuss these issues in detail and to point out the relevant risks and known complications associated with them.     

Results of endoscopic third ventriculostomy

ETV is emerging as the treatment of choice for aqueductal stenosis caused by anatomic, inflammatory, and selected neoplastic etiologies. The technique has also proven useful in the pathologic diagnosis and treatment of these conditions. Long-term results of this procedure and comparison to standard shunting procedures are necessary to define indications for patients with pathologic findings in the intermediate response groups. Development of new studies for pre-operative assessment of CSF absorptive capacity and quantitative postoperative measures of ventriculostomy function would be invaluable additions to our ability to assess candidates for this procedure and their eventual outcome. Further study and technical refinements will, no doubt, lead to many more potential uses for these procedures in the treatment of hydrocephalus and its associated etiologies. The challenge for neuro-surgeons will be to define the operative indications and outcomes, while refining techniques for safely performing these useful procedures.     

第三脑室底造瘘治疗脑积水的手术并发症

目的 探讨第三脑室底造瘘治疗脑积水产生手术并发症的原因及预防措施。方法 对13例（15例次）行第三脑室底造瘘术治疗脑积水出现并发症的情况进行回顾性分析。结果 本组患者出现脑室内感染2例、膜膜下积液1例、造瘘口再堵塞1例、术中出血后的血凝块堵塞第三脑室形成脑疝1例。并发症的主要原因为手术设备的不良和先期经验的不足。结论 采用良好的手术设备,提高对各种并发症发生原因的不足,可减少手术并发症的发生。     

Selecting patients for endoscopic third ventriculostomy

ETV using contemporary instrumentation has been used for more than 50 years, but its use has become widespread only in the last 10 to 15 years. Randomized prospective trials comparing ETV with shunts are needed before definitive statements can be made about the role of the former in managing the many forms of hydrocephalus. The absolute and relative contraindications for the use of ETV in the management of hydrocephalus are shown in the Box 1 on this page. It is important not to presume that a specific radiographic or clinical feature would prevent a patient from responding to this rather new procedure without testing the hypothesis. Patients should be given as much information as possible regarding the risks and benefits of ETV so they can participate in the decision-making process. When should the role of ETV in the management of hydrocephalus be discussed with a patient? At the initial diagnosis of hydrocephalus, the patient or family should be informed of this potential alternative to shunting for the management of hydrocephalus. I also believe that patients with working shunts who are being followed chronically should be informed about ETV as a potential treatment option when their shunt fails. Every shunt failure or infection should be viewed as an opportunity to explore the possibility that the patient could become shunt independent.     

An endoscopic technique for third ventriculostomy

A simple technique for performing third ventriculostomy is described. The technique utilizes a fiberoptic endoscope inserted through a small burr hole over the coronal suture. The technique has been successfully employed in five patients without complications. If better criteria for selection of patients for third ventriculostomy could be established, this procedure would provide an ideal means for treatment.     

A cost-effectiveness analysis of endoscopic third ventriculostomy

OBJECTIVE: Endoscopic third ventriculostomy (ETV) is currently the principal alternative to cerebrospinal fluid shunt placement in the management of pediatric hydrocephalus. Cost-effectiveness analysis can help determine the optimal strategy for integrating these different approaches. METHODS: All patients (n = 28) who underwent ETV at British Columbia's Children's Hospital between 1989 and 1998 were matched for age, pathogenesis, and number of previous shunt procedures, with patients treated with cerebrospinal fluid shunts. To perform a cost-effectiveness analysis, hydrocephalus-related resource consumption and outcome (determined as the number of hydrocephalus treatment-free days during follow-up) were then retrospectively identified. Cost data were linked to resource use to provide a total cost for all resources used. Costs and outcomes were discounted annually at 5% by standard economic analysis methods. RESULTS: Twenty-four of 28 ETV patients had obstructive hydrocephalus. Over equivalent follow-up periods (median, 35 mo), the ETV success rate (defined by need for reoperation) was 54%. One hydrocephalus-related death and one hemiparesis occurred in the ETV group. No permanent procedure-related morbidity or mortality was seen in the shunt group. The cost/effect ratios for the two groups were similar. The additional incremental resource use by the shunt group included six readmissions and eight reoperations. ETV mean costs per patient were $10,570 +/- $7628, versus $10,922 +/- $8722 for the shunt group (Canadian dollars for the year 2000). Costs accrued more quickly for the shunt group as time passed. The additional incremental outcome benefit to the endoscopy group was 86 treatment-free days (3.07 d per patient [95% confidence interval, -7.56 to 13.70 d]). Neither of these differences was statistically significant. CONCLUSION: In this matched cohort, ETV was not significantly less costly or more effective over a median 35 months of follow-up, with a 54% initial ETV success rate, even before the additional morbidity and mortality encountered were taken into account. The time course for the accrued costs suggests that a larger cohort, longer follow-up, or higher success rates are needed to demonstrate the cost-effectiveness of this therapy.     

Imaging correlates of successful endoscopic third ventriculostomy

OBJECT: The goal of this study was to determine and compare imaging correlates in pediatric patients who underwent successful or failed endoscopic third ventriculostomies (ETVs). To this end, the authors measured ventricular size changes and the presence of cerebrospinal fluid (CSF) flow void in both groups of children following ETV. METHODS: Images obtained in children with hydrocephalus immediately before and at least 30 days after having undergone ETV were reviewed by four independent observers (two blinded and two nonblinded). Each observer independently measured the frontal and occipital horn ratio ([FOR], a reliable and valid measure of ventricular size) and provided a subjective assessment of the presence of a flow void at the ETV site, the degree of periventricular edema, and the amount of CSF over the cerebral hemispheres. There were 29 children whose mean age was 6.6 years at the time of ETV and who had a mean postoperative follow-up period lasting 1.6 years. Postoperatively, the mean reduction in ventricular size (as measured using the FOR) was 7% (95% confidence interval [CI] 3-11%) in cases that were deemed failures (eight patients) and 16% (95% CI 12-20%) in clinically successful cases (21 patients). This reduction was significantly greater in cases of clinical success compared with those that were deemed failures (p = 0.03, t-test). There were no substantial differences between blinded and nonblinded assessments. Flow void was present in 94% of successes and absent in 75% of failures (p = 0.01, Fisher's exact test). The other subjective assessments were not significantly different between the groups of successes and failures. CONCLUSIONS: Ventricular size appears to be somewhat reduced in both groups of patients who underwent clinically successful and failed ETV; however, the reduction is significantly greater among clinically successful cases. The presence of a flow void also appears to correlate with clinical success and its absence with clinical failure.     

Blood biochemistry following endoscopic third ventriculostomy.

BACKGROUND: Endoscopic third ventriculostomy (ETV) is now an accepted treatment for obstructive hydrocephalus. Anandh et al. have reported postoperative hyperkalemia following ETV. However, due to small sample size (20 patients), the authors could not confirm their hypothesis (8). Therefore, we have conducted the present study in order to investigate postoperative blood chemistry following ETV. PATIENTS AND METHODS: The computerized database and the medical records of 50 patients who underwent ETV under general anesthesia were studied. Blood chemistry for all patients was done preoperatively as well as for three consecutive days postoperatively. Preoperative and peak postoperative serum blood chemistry variables were compared by using Student's t-test for paired samples. A p value of < 0.05 was considered significant. RESULTS: Preoperative serum K+ concentration mean value was 4.8 +/- 0.7 mmol/l. In the consecutive two postoperative days serum K+ levels mean values were 4.4 +/- 0.8 and 4.3 +/- 0.8 mmol/l with significantly lower levels compared to preoperative values (p < 0.05). CONCLUSIONS: Although significantly lower K+ values have occurred in our series postoperatively, they were of no clinical significance. Moreover, our results were in contrast to Anandh et al. who used lactated Ringer's (LR) as irrigation fluid which led to postoperative hyperkalemia. We recommend the use of normal saline as irrigation fluid instead of LR.     

Chronic subdural collection after endoscopic third ventriculostomy

Summary Endoscopic third ventriculostomy (ETV) is considered a safe technique for the treatment of obstructive hydrocephalus. We describe a case of chronic subdural haematoma (CSDH) after ETV, revealed by MRI four weeks after the procedure, and requiring surgical evacuation, in a 69y.o. asymptomatic male patient. In our opinion, overdrainage may evolve also in endoscopic treatment of obstructive hydrocephalus. This complication could be the starting point of the subdural collection. We review the literature and discuss the causes that may lead to CSDH after ETV procedure.     

The incidence of bradycardia during endoscopic third ventriculostomy

The incidence of bradycardia during endoscopic third ventriculostomy (ETV) is unknown. In an attempt to determine that incidence, we studied 49 pediatric patients with obstructive hydrocephalus who underwent ETV during general anesthesia. The median age was 54.5 mo (range 1-108 mo) and the median weight was 12.2 kg (range 2.4-22 kg). The heart rate was measured continuously in which four stages were identified for data analysis. Stage A is the preoperative phase, stage B is 5 min before perforating the floor of the third ventricle, stage C during perforation, and stage D after perforating the floor of the third ventricle. Three readings were recorded at each stage, then averaged. The mean values of the heart rate at stages A, B, C, and D were 146 +/- 27, 151 +/- 26, 87 +/- 32, and 143 +/- 24 bpm respectively. A significant decrease in the heart rate was determined in stage C compared with stage B (P: < 0.05). The incidence of bradycardia was 41%. Alerting the surgeon to perforate the floor of the third ventricle or withdraw the scope away from it was sufficient to resolve the bradycardia. We concluded that serious bradycardia might occur during ETV, mostly because of mechanical factors and can be resolved without medications. Implications: The use of endoscopy for treating pediatric patients with increased intracranial pressure is a new surgical procedure. These patients require general anesthesia with continuous heart rate monitoring. We have observed a high incidence of decrease in heart rate. If a decrease in heart rate occurs, alerting the surgeon to speed the procedure would be an effective treatment.     

Changes in ventricular size after endoscopic third ventriculostomy

Summary Background. There is general consensus that a successful endoscopic third ventriculostomy is usually followed by a decrease of ventricular size without reaching their normal size. This study was performed to determine how the change related to clinical outcome, how it developed chronologically and whether the change in ventricular size was different in acute and chronic forms of hydrocephalus. Method. Fifty-five of 74 patients who had undergone endoscopic third ventriculostomy during the period 1997–2004 were selected by the criterion that they had both pre-operative and post-operative films and no neurosurgical manoeuvre other than a surgically successful endoscopic third ventriculostomy in the time span between both radiological studies. Ventricular size was measured with the Evans index, third ventricle index, cella media index and ventricular score. Median age was 51 years (interquartile range, 27–65 years). Results. The change in ventricular size detected shortly after surgery is related to clinical outcome for all ventricular ratios, except the cella media index (p = 0.08). When third ventriculostomy is clinically successful, there is a gradual decrease of ventricular size over a period of more than three months (p < 0.0001 for all ventricular ratios). The reduction is more prominent in acute hydrocephalus than in chronic forms for all ventricular ratios, except the Evans index (p = 0.12). The third ventricle exhibits the greatest reduction (25% with a 95% confidence interval: 15.4–34.5) and determines a different pattern of change in ventricular size after endoscopic third ventriculostomy between acute and chronic hydrocephalus. Conclusions. A decrease of the ventricular size detected soon after endoscopic third ventriculostomy is associated with a satisfactory clinical outcome. This response continues during the first few months after surgery. The reduction is more prominent in acute forms of hydrocephalus. Correspondence: David Santamarta, Servicio de Neurocirugía, Hospital de León, Altos de Nava s/n, 24071 León, Spain.     

Is endoscopic third ventriculostomy an internal shunt alone?

OBJECTS: This study was made to define the mechanism of endoscopic third ventriculostomy (ETV) in the various forms of hydrocephalus. METHODS: One hundred and forty patients with various forms of hydrocephalus treated by ETV are reviewed. The series includes 75 cases (53.5%) of triventricular obstructive hydrocephalus (group 1), 20 (14.3%) with hydrocephalus following CSF infection or hemorrhage (group 2) and 45 (32.3%) with idiopathic normal pressure hydrocephalus (group 3). Factors which have been considered include type and etiology of the hydrocephalus, intraoperative evidence of downward and upward movement of the third ventricular floor after the stomy, patient outcome and rate of shunt-independent cases. RESULTS: The overall rate of successful ETV was 79.3% (111/140 shunt-free patients). The success rate was 88% (66/75) in group 1, 60% (12/20) in group 2 and 73.4% (33/45) in group 3. The intraoperative finding of significant movement of the third ventricular floor after the stomy was evidenced in 121/140 cases (86.4%) and particularly in all cases of group 1, in 9/20 (45%) of group 2 and in 37/45 (82%) of group 3. CONCLUSIONS: The relatively high rate of success of ETV in various forms of hydrocephalus and the intraoperative finding of mobility of the third ventricle floor after the stomy suggest that the first mechanism of the ETV is the restoration of pulsatility of the ventricular walls. This results in restoration of the CSF flow from the ventricular system into the subarachnoid spaces and normalization of the CSF dynamics. Accordingly, ETV is not only an internal shunt, but it primarily influences the capacity of the brain pulsatility to ensure CSF flow.     

A simplified endoscopic third ventriculostomy under local anesthesia.

The aim of this study is the analysis of our experience with awake endoscopic third ventriculostomy (ETVS) in hydrocephalic patients. From September 1994 to December 2001, 24 neuroendoscopic procedures were performed under local anesthesia. Local infiltration was administered using a bupivacaine and lidocaine mixture. Analgesics were titrated to the effect. A free-hand technique with a flexible endoscope was adopted in 24 patients with primitive and secondary (neoplastic) hydrocephalus. ETVS was performed successfully in all cases. No procedure needed to be discontinued due to seizures, bleeding or agitation. Dural incision/coagulation and Fogarty dilatation proved to be the most painful maneuvers requiring, sometimes, supplemental analgesic administration. No intraoperative complications were observed; however, two asymptomatic trajectory hematomas were incidentally discovered two and three days after the operation, respectively. Awake ETVS is a valuable alternative procedure that can be adopted in adult cooperative patients, provided that the procedure is done in an essential and fast way with the free-hand technique, by means of a flexible endoscope, and with the assistance of an anesthesiologist.