Shunt Survival Rates Research Articles

Time to First Shunt Failure in Pediatric Patients over 1 Year Old: A 10-Year Retrospective Study

Studies comparing alternatives to ventriculoperitoneal (VP) shunting for treatment of hydrocephalus have often relied upon data from an earlier era that may not be representative of contemporary shunt survival outcomes. We sought to determine the shunt survival rate of our cohort and compare our results to previously published shunt survival and endoscopic third ventriculostomy (ETV) success rates. We identified 95 patients between 1 and 18 years of age, who underwent initial VP shunt placement between January 2001 and December 2010. Our study shows a shunt survival rate of 85% at 6 months and 79% at 2 years, for initial shunts in pediatric patients over 1 year of age in this cohort. The overall infection rate was 3%. This compares favorably with published success rates of ETV at similar time points as well as with the rate of infection. This suggests that ventricular shunting remains a viable alternative to ETV in the older child.

No significant improvement in the rate of accurate ventricular catheter location using ultrasound-guided CSF shunt insertion: a prospective, controlled study by the Hydrocephalus Clinical Research Network

Cerebrospinal fluid shunt ventricular catheters inserted into the frontal horn or trigone are associated with prolonged shunt survival. Developing surgical techniques for accurate catheter insertion could, therefore, be beneficial to patients. This study was conducted to determine if the rate of accurate catheter location with intraoperative ultrasound guidance could exceed 80%. The authors conducted a prospective, multicenter study of children (< 18 years) requiring first-time treatment for hydrocephalus with a ventriculoperitoneal shunt. Using intraoperative ultrasound, surgeons were required to target the frontal horn or trigone for catheter tip placement. An intraoperative ultrasound image was obtained at the time of catheter insertion. Ventricular catheter location, the primary outcome measure, was determined from the first postoperative image. A control group of patients treated by nonultrasound surgeons (conventional surgeons) were enrolled using the same study criteria. Conventional shunt surgeons also agreed to target the frontal horn or trigone for all catheter insertions. Patients were triaged to participating surgeons based on call schedules at each center. A pediatric neuroradiologist blinded to method of insertion, center, and surgeon determined ventricular catheter tip location. Eleven surgeons enrolled as ultrasound surgeons and 6 as conventional surgeons. Between February 2009 and February 2010, 121 patients were enrolled at 4 Hydrocephalus Clinical Research Network centers. Experienced ultrasound surgeons (> 15 cases prior to study) operated on 67 patients; conventional surgeons operated on 52 patients. Experienced ultrasound surgeons achieved accurate catheter location in 39 (59%) of 66 patients, 95% CI (46%-71%). Intraoperative ultrasound images were compared with postoperative scans. In 32.7% of cases, the catheter tip moved from an accurate location on the intraoperative ultrasound image to an inaccurate location on the postoperative study. This was the most significant factor affecting accuracy. In comparison, conventional surgeons achieved accurate location in 24 (49.0%) of 49 cases (95% CI [34%-64%]). The shunt survival rate at 1 year was 70.8% in the experienced ultrasound group and 66.9% in the conventional group (p = 0.66). Ultrasound surgeons had more catheters surrounded by CSF (30.8% vs 6.1%, p = 0.0012) and away from the choroid plexus (72.3% vs 58.3%, p = 0.12), and fewer catheters in the brain (3% vs 22.4%, p = 0.0011) and crossing the midline (4.5% vs 34.7%, p < 0.001), but they had a higher proportion of postoperative pseudomeningocele (10.1% vs 3.8%, p = 0.30), wound dehiscence (5.8% vs 0%, p = 0.13), CSF leak (10.1% vs 1.9%, p = 0.14), and shunt infection (11.6% vs 5.8%, p = 0.35). Ultrasound-guided shunt insertion as performed in this study was unable to consistently place catheters into the frontal horn or trigone. The technique is safe and achieves outcomes similar to other conventional shunt insertion techniques. Further efforts to improve accurate catheter location should focus on prevention of catheter migration that occurs between intraoperative placement and postoperative imaging. Clinical trial registration no.: NCT01007786 ( ClinicalTrials.gov ).

Shunt survival rates by using the adjustable differential pressure valve combined with a gravitational unit (proGAV) in pediatric neurosurgery

Overdrainage is a chronic complication in shunted pediatric patients with hydrocephalus. The use of adjustability of differential pressure (DP) valves in combination with antisiphoning devices may help to overcome this sequela and may diminish the rate of possible shunt failures. The purpose of this retrospective study is to report our experience on shunt survival and infection rate with an adjustable DP valve with integrated gravitational unit in pediatric hydrocephalus. The proGAV consists of an adjustable differential pressure (DP) valve and a gravitational unit. During the time period of July 2004 and December 2009, a total of 237 adjustable gravitational valves were used in 203 children (age, 6.5 ± 6.54; 0-27years). In the follow-up period, valve and shunt failures as well as rate of infection were recorded. Within the average follow-up time of 21.9 ± 10.3months (range, 6-72months), the valve survival rate was 83.8%. The overall shunt survival rate including all necessary revisions was 64.3%. Looking at the group of infants (<1year of age) within the cohort, the valve survival rate was 77.3% and the shunt survival rate was 60.9%. The overall infection rate was 4.6%. In a concept of avoiding chronic overdrainage by using the proGAV in hydrocephalic children, we observed a good rate of valve and shunt survival. Compared to previous reported series, we experienced the proGAV as a reliable tool for the treatment of pediatric hydrocephalus.

A MULTICENTER STUDY OF FACTORS INFLUENCING CEREBROSPINAL FLUID SHUNT SURVIVAL IN INFANTS AND CHILDREN

To identify factors influencing the duration of cerebrospinal fluid shunt survival after initial placement and after subsequent revisions. We conducted a retrospective cohort study using the Pediatric Health Information System database, which contains resource use data from 37 tertiary care children's hospitals. Children younger than 18 years who underwent initial cerebrospinal fluid placement between January 1, 2000, and December 31, 2005, were eligible. During the study period, 20.2, 7.5, and 6.9% of 7399 patients required one, two, or three or more shunt revisions, respectively. Shunt survival rates were lower with each subsequent shunt revision. In multivariable Cox proportional hazards analysis, children undergoing shunt placement in the Northeast census region had a longer duration of shunt survival between initial placement and both the first (adjusted hazard ratio, 0.74; 95% confidence interval, 0.55-0.99) and second (adjusted hazard ratio, 0.66; 95% confidence interval, 0.51-0.86) revisions. Young age and a principal diagnosis of obstructive hydrocephalus were also associated with a higher risk of failure after initial placement; age-related variation in shunt survival persisted after the first but not the second revision. Among patients with multiple shunt revisions, those with early revision (i.e., revision <60 d after placement) had a shorter shunt survival time after subsequent revisions (adjusted hazard ratio for second revision, 1.30; 95% confidence interval, 1.11-1.52). Regional variation in the risk of ventricular shunt revision exists, and young infants are at the highest risk for shunt failure. Risk factors for the duration of shunt survival differ between the initial and subsequent revisions.

ADJUSTABLE VALVES IN NORMAL-PRESSURE HYDROCEPHALUS

We sought to assess the value of adjusting shunt valve opening pressure, complications, and outcomes with the use of an adjustable shunt valve in the treatment of patients with normal-pressure hydrocephalus (NPH). In a single-center retrospective study, 231 adjustable valves (range, 30-200 mm H2O) were the first shunt implantations in 147 patients with idiopathic NPH (INPH) and 71 patients with secondary NPH (SNPH). The effect of adjustment on gait disturbance, cognitive impairment, urinary incontinence and other symptoms were evaluated, and an improvement index was created. In the INPH group, 138 adjustments were performed in 49.0% of the patients (average, 0.94 adjustments/patient). For the SNPH group, 49 adjustments were performed in 32.4% of the patients (average, 0.69 adjustments/patient). The reasons for adjustment were overdrainage in 48 patients (25.7%), underdrainage in 98 patients (52.4%), subdural hematoma in 37 patients (19.8%), and other reasons in 2 patients (2.1%). Clinical status improved after 56 (49.1%) of all 114 adjustments, whereas 23 (42.6%) of 54 minor (< or = 20 mm H2O) and 33 (66.0%) of 50 larger adjustments improved the patient's clinical status. The correlation of the improvement index with the size of the individual adjustments was not significant. Complications occurred in 43 (19.7%) of 218 patients, valve malfunction occurred in 3 patients (1.3%), infection occurred in 14 patients (6.4%), and nontraumatic subdural effusion occurred in 15 patients (6.9%; 8 were treated by adjustment alone). The 5-year shunt survival rate was 80.2%. Outcomes were excellent or good in 71 (78.9%) of 90 patients with INPH and in 30 (69.8%) of 43 patients with SNPH. Noninvasive, particularly consecutive, minor or single larger adjustments to the valve opening pressure can further improve outcome in patients with NPH who undergo shunting.

A mathematical model of survival in a newly inserted ventricular shunt

The object of this study was to mathematically model the prognosis of a newly inserted shunt in pediatric or adult patients with hydrocephalus. A structured search was performed of the English-language literature for case series reporting shunt failure, patient mortality, and shunt removal rates after shunt insertion. A metaanalytic model was constructed to pool data from multiple studies and to predict the outcome of a shunt after insertion. Separate models were used to predict shunt survival rates for children (patients < 17 years old) and adults. Shunt survival rates in children and adults were calculated for 1 year (64.2 and 80.1%, respectively), 5 years (49.4 and 60.2%, respectively), and the median (4.9 and 7.3 years, respectively). The longer-term rates predicted by the model agree closely with those reported in the literature. This model gives a comprehensive view of the fate of a shunt for hydrocephalus after insertion. The advantages of this model compared with Kaplan-Meier survival curves are discussed. The model used in this study may provide useful prognostic information and aid in the early evaluation of new shunt designs and techniques.

LAPAROSCOPIC PERITONEAL CATHETER PLACEMENT

Although cerebrospinal fluid shunting remains one of the most common neurosurgical procedures, it is fraught with high infection, blockage, and reoperation rates. It has been estimated that the economic cost of ventriculoperitoneal shunting exceeds $1 billion annually. A new laparoscopic technique that eliminates abdominal incisions overlying shunt hardware was applied to 111 patients requiring ventriculoperitoneal shunts in an effort to decrease the morbidity associated with shunting. All patients who required ventriculoperitoneal shunt insertion were eligible for this surgical technique. Patient selection was based on availability of both surgical teams (general surgery and neurological surgery) at the time of surgery. Using this technique, the distal shunt catheter is tunneled directly from the head into the peritoneal cavity under laparoscopic guidance without a skin incision directly overlying the distal catheter insertion site. Patients were followed prospectively for signs and symptoms related to shunt dysfunction, shunt infection, and incision morbidity. One hundred eleven patients underwent 113 laparoscopic ventriculoperitoneal shunt surgeries between February 2003 and December 2004. The average follow-up period was 21.7 months (range, 12-34 mo). Nearly half of the patients (49%) were discharged the next morning and the majority (81%) was discharged within 2 days of surgery. Overall, 15 patients experienced complications requiring reoperation (13.5%) with a 1-year shunt survival rate of 91%. One patient (0.9%) acquired a new shunt infection, whereas two patients (1.8%) developed recurrence from a previous shunt infection. There were no abdominal incision-related complications. This simplified laparoscopic shunt placement technique, which requires no overlying abdominal incisions, can be performed quickly with high shunt survivability and low infection rates. Furthermore, the laparoscopic method has the advantage of fast recovery time, elimination of preperitoneal or misplaced catheters, and decreased abdominal incision morbidity. The procedure can be performed by either a multidisciplinary team or entirely by neurosurgeons.

Pediatric gravitational shunts: initial results from a prospective study

The authors' goal in this paper was to evaluate prospectively the efficacy and safety of a new pediatric gravitational shunt to determine whether it warrants inclusion in a randomized, controlled trial with other shunts. A total of 55 children between the ages of 0 and 6 years (median age 0.5 years, average age 4+/-6 years) underwent primary shunt implantation; all received the Miethke Paedi-GAV. The follow-up period ranged between 12 and 77 months (mean 47+/-21 months). The primary end point of the study was the first shunt failure necessitating revision. The 1- and 2-year shunt survival rates were 75 and 68%, respectively. The average failure-free shunt survival duration was 1423 +/- 641 days. Based on imaging findings, no slitlike ventricles occurred. The complication rate was 33%, and the median time to shunt failure was 45 days. Underdrainage occurred in one child (1.8%) and overdrainage in two children (3.6%). These preliminary results prove the Miethke Paedi-GAV to be a safe and effective pediatric shunt worthy of inclusion in a randomized comparison with other shunts in the pediatric population.

The Strata programmable valve for shunt-dependent hydrocephalus: the pediatric experience at a single institution

The Medtronic PS Medical Strata valve has pressure flow characteristics that are noninvasively adjusted with a magnetic tool. The objective of this study was to examine its efficacy during our initial experience with it in shunt-dependent children. A retrospective review of 53 children with a median age of 2.0 years who had 61 Strata valves implanted. The Strata valve is efficacious in the treatment of shunt-dependant hydrocephalus in children. The 1-year shunt survival rate of 67.2% is comparable to that previously reported from a multicenter trial. Of the 30 therapeutically aimed adjustments during the study period, 16 (53.3%) resulted in improvement in abnormal signs or symptoms. Our data indicate that adjustments can be used to treat signs or symptoms of cerebrospinal fluid overdrainage or underdrainage, which may obviate the need for additional surgery.

Shunt insertion in the summer: is it safe?

The potential for increased complications related to the arrival of new residents in July each year has not previously been demonstrated in the neurosurgical literature. The authors investigated this phenomenon in children undergoing cerebrospinal fluid shunt surgery. Data were obtained from a multicenter hydrocephalus clinical trials database and from hospital admission records in English-speaking Canada. Data pertaining to patients treated in July and August were compared with those pertaining to patients treated during the remainder of the year. The incidence of shunt failure, shunt infection, neurological deficits, wound infection, technical errors, and death were compared using a chi-square test for categorical outcomes, means for continuous outcomes, and survival analysis for time-dependent outcomes. In the hydrocephalus clinical trials database, 138 of 737 patients were treated in July and August. The median duration of shunt lifespan (hereafter referred to as "shunt survival") was 1.7 years for patients treated during the summer months and 2.4 years for those treated throughout the rest of the year (p = 0.10); for shunt infection the figures were 13.8 and 8.8% (p = 0.08) of the total number of cases, and for wound dehiscence they were 2.9 and 0.7% (p = 0.05), respectively. When all shunt procedures were included, an examination of shunt survival and infection incidence rates recorded in the Canadian Hospital Discharge Database seemed to imply a significant advantage to having surgery between September and June (log-rank statistic = 7.10, p = 0.008). The data suggest a "July effect" on some outcomes related to shunt surgery, but the effect was small. Nonetheless, the potential morbidity of shunt failure, infection, and the cost of treatment indicate that continued vigilance and appropriate supervision of new staff by attending surgeons is warranted.

The Gravity-Assisted Paedi-Gav Valve in the Treatment of Pediatric Hydrocephalus

Objective: A single-center, prospective, nonrandomized pilot study was performed to assess the Paedi-Gav gravity-assisted valve for the treatment of pediatric patients with hydrocephalus. Methods: Participants were pediatric patients (age <16 years) who were candidates for a hydrocephalus shunt system that required a valve insertion at the time of enrollment. The primary outcome event was shunt malfunction; subclassified into shunt obstruction, shunt overdrainage, loculated ventricles, or infection. The shunt obstructions were further subclassified according to site. A total of 32 patients were enrolled onto the study, with 2 undergoing first shunt insertion after failed ventriculostomy and 30 undergoing shunt revisions. On average, the patients had had 3.3 shunt procedures prior to insertion of a Paedi-Gav valve. Results: During a follow-up interval of minimum 52 weeks and a median of 24 months after the first implantation on-study, shunt revisions were required in 17 (53.1%) of the 32 patients. The 12-month shunt-survival rate without revision of any component was 53%, with a median shunt-survival time of 388 days. The most common reasons for shunt revision were shunt obstructions (12/17) and overdrainage (3/17). Shunt obstructions were caused by valve-related failures (9/12) and distal obstructions (3/12). Conclusion: Although the small number of patients enrolled in this study warrants cautious conclusions, the overall results are comparable to those reported for primary shunt insertions with conventional valves in pediatric patients with hydrocephalus. Although this study provides a rationale for examining the Paedi-Gav gravity-assisted shunt valve in a larger prospective randomized controlled trial, the shunt failure pattern, with a rather high frequency of valve-related failures, may indicate potential for further improvements in the valve design and/or manufacturing.

Assessing the validity of the endoscopic shunt insertion trial: did surgical experience affect the results?

Most surgical procedures are associated with a learning curve in which the success rate is lower early in the experience before mistakes have been identified and modifications made to the procedure. Negative results obtained early in a trial's learning curve may be a matter of timing rather than a reflection of the procedure's effectiveness. The recently published results of the Endoscopic Shunt Insertion Trial (ESIT) represent the notion that endoscopically placed shunts were no more likely to survive than conventionally placed shunts. This negative result may be due to inexperience in performing endoscopic surgeries. . Surgical experience was assessed in two ways. Shunt survival rates were compared between cases treated endoscopically in the 1st and last years of the ESIT. The effect of center volume was evaluated using a Cox proportional hazard model in which the following variables were analyzed: age at registration, the diagnosis of myelomeningocele, head size, method of shunt placement (endoscopic compared with conventional), and center volume. There was no difference in survival (endurance) of the shunt between patients enrolled in the 1st and last years (log rank = 0.08, p = 0.77). Likewise, no variable in the Cox multivariate model, including center volume, was a significant factor in predicting shunt survival. The primary result of the ESIT was found to be internally valid. The fact that endoscopic shunt placement did not benefit patients evaluated in the study was not due to early timing of the trial. Any learning curve among the participating surgeons did not adversely affect the results.

Ventricular shunting for hydrocephalus in children: patients, procedures, surgeons and institutions in English Canada, 1989–2001

Ventricular shunting remains the principle and most generally applicable method to treat hydrocephalus in children. This report describes the demographics of this treatment in English Canada during the period of 1989 to 2001. Hospital discharge records were obtained for patients less than 18 years who had a shunt inserted or revised. A database was constructed relating to patients and procedures. 5,947 patients underwent ventricular shunting for hydrocephalus during this period. Two hundred sixty-one surgeons working in 73 institutions provided 12,106 interventions (ventriculoperitoneal shunts, 5,009; ventriculoatrial, 119; ventriculopleural, 28; revisions, 6,950). Infections occurred in 1,059 procedures. Over the study period, the median number of procedures per surgeon per year was 2, with 75% of surgeons performing 5 or fewer procedures in children per year. Although many surgeons operated on children throughout the study period, many did not acquire substantial cumulative experience. Overall infection rate was 8.6%. Surgeon infection rates were greater than or equal to 20% during the first 4 years of practice and thereafter fell to and remained in the 10% range. The mean shunt survival rate at 12 months of individual surgeons varied between 50% and 60%, regardless of the number of years of experience. However, performance variability as measured by the standard deviation of 12-month survival rates for all surgeons, adjusted for years of experience, varied widely until the fifth year of practice. The average number of procedures per year for treating hospitals was 2 with 75%, 50% of the institutions provided 10 or fewer procedures. The mean institutional infection rate was 11.4%. It is concluded that quality monitoring of infection rate and duration of shunt function remains critical because many surgeons and hospitals provide care to children with hydrocephalus infrequently. Variability in infection rates and shunt survival at 12 months are a function of surgeon experience, measured by years of practice. Variability in outcome decreases with increasing surgeon experience.—Thomas A. Angerpointner

Adjustable Valves in Normal-pressure Hydrocephalus: A Retrospective Study of 218 Patients

We sought to assess the value of adjusting shunt valve opening pressure, complications, and outcomes with the use of an adjustable shunt valve in the treatment of patients with normal-pressure hydrocephalus (NPH). In a single-center retrospective study, 231 adjustable valves (range, 30-200 mm H(2)O) were the first shunt implantations in 147 patients with idiopathic NPH (INPH) and 71 patients with secondary NPH (SNPH). The effect of adjustment on gait disturbance, cognitive impairment, urinary incontinence and other symptoms were evaluated, and an improvement index was created. In the INPH group, 138 adjustments were performed in 49.0% of the patients (average, 0.94 adjustments/patient). For the SNPH group, 49 adjustments were performed in 32.4% of the patients (average, 0.69 adjustments/patient). The reasons for adjustment were overdrainage in 48 patients (25.7%), underdrainage in 98 patients (52.4%), subdural hematoma in 37 patients (19.8%), and other reasons in 2 patients (2.1%). Clinical status improved after 56 (49.1%) of all 114 adjustments, whereas 23 (42.6%) of 54 minor (< or =20 mm H2O) and 33 (66.0%) of 50 larger adjustments improved the patient's clinical status. The correlation of the improvement index with the size of the individual adjustments was not significant. Complications occurred in 43 (19.7%) of 218 patients, valve malfunction occurred in 3 patients (1.3%), infection occurred in 14 patients (6.4%), and nontraumatic subdural effusion occurred in 15 patients (6.9%; 8 were treated by adjustment alone). The 5-year shunt survival rate was 80.2%. Outcomes were excellent or good in 71 (78.9%) of 90 patients with INPH and in 30 (69.8%) of 43 patients with SNPH. Noninvasive, particularly consecutive, minor or single larger adjustments to the valve opening pressure can further improve outcome in patients with NPH who undergo shunting.

The Shunt Design Trial: Variation in Surgical Experience Did Not Influence Shunt Survival

Introduction: An international multicenter randomized trial comparing standard pressure differential valves, Orbis Sigma valves and PS Medical Delta valves for children with newly diagnosed hydrocephalus failed to show a difference in the time to first shunt failure. Surgeons’ prior experience with the three valves varied. This analysis was performed to assess whether lack of surgical experience with any of the valves could explain the overall negative result. Methods: (1) Shunt survival was compared at high- and low-volume centers. (2) The 1-year shunt survival rates (±95% confidence interval) for patients entered in the first quarter and the last quarter of the 25-month accrual period were compared (for all patients, and for each shunt). Results: Survival curves for high- and low-volume centers were similar. Ninety of the 344 randomized patients were accrued in the first quarter and 93 in the last quarter. The 1-year shunt survival for all patients entered in the first quarter was 72% (±11%) compared to 64% (±10%) for patients entered in the last quarter. The shunt-specific results were 66% (±20%) compared to 54% (±20%) for Delta valve patients, 75% (±20%) compared to 70% (±17%) for standard valve patients and 76% (±18%) compared to 66% (±16%) for Orbis Sigma patients. Discussion: Shunt survival did not improve as surgeons accumulated experience over the course of the study. Although participating surgeons had varying levels of experience with the different shunts at the start of the trial, this does not appear to explain the overall negative trial result.

The use of pleuroperitoneal shunts in the management of persistent chylothorax in infants

Background/Purpose: The development of chylothorax is a serious and often life-threatening clinical entity that may cause profound respiratory, nutritional, and immunologic complications and has become increasingly common in recent years. Optimal management of this problem has not been well defined because medical therapy has a significant failure rate. Surgical treatment of complicated chylothorax has become a mainstay of care. Methods: Over the last 36 months, seven infants had a pleuroperitoneal shunt placed for the management of refractory chylothorax. Ages ranged from 10 to 66 days with a weight between 1,000 to 4,850 g. Five of the seven infants were ventilator dependent. The etiologies were congenital in four and acquired in three with one related to a cardiothoracic procedure, one related to superior vena caval thrombosis, and one postoperative diaphragmatic hernia repair with superior vena caval thrombosis. Associated conditions included a left congenital diaphragmatic hernia, asplenia, isolated renal agenesis, bronchopulmonary dysplasia, and a patent ductus arteriosus. Each patient was unresponsive to thoracentesis, tube thoracostomy, and dietary manipulation with preoperative volume of chest tube output ranging from 50 to 162 cc/kg/d. The duration of preoperative therapy in congenital occurrences ranged from 10 to 46 days (average, 22 days). A Denver double-valved shunt system was used and catheters were implanted under general anesthesia. Manual pumping was required postoperatively on an hourly basis. Results: All seven patients had excellent results with the elimination of the chylothorax and resolution of symptoms. There were two complications. Shunt survival rate was six of seven (86%). Shunt removal ranged from 24 to 79 days (average, 44 days). Patient survival rate was five of seven (71%) with one infant dying of progressive pulmonary disease and one infant dying from viral sepsis; both had functioning shunts. One patient remains ventilator dependent secondary to chronic lung disease from prematurity. Conclusions: Pleuroperitoneal shunting is safe, simple, and an effective treatment of chylothorax in infants despite their size, age, or degree of prematurity.

Functioning periods and complications of 246 cerebrospinal fluid shunting procedures in 208 children.

To investigate the functioning periods and the causes of cerebrospinal fluid shunt failures, 246 shunts inserted in 208 children from October 1985 to August 1992 at the authors' institute were retrospectively reviewed. The mean age at shunt insertion was 4.0 years and the reasons for the shunting procedures were congenital hydrocephalus (47.6% per procedure), tumor-associated hydrocephalus (21.1%), postmeningitic hydrocephalus (11.8%), congenital cyst (10.6%) and others (8.9%). All except 2 were shunted to the peritoneal cavity. Forty-five operations for shunt failure were done (18.3%) during the follow-up period (mean, 32 months). The functioning (shunt survival) rates at 6, 12, 24 and 36 months after surgery were 91.6%, 86.6%, 83.6% and 82.9%, respectively. The complications were mechanical malfunction (12.2%), infection (4.1%), subdural fluid collection which required drainage (1.6%) and migration (0.4%). About half of the mechanical malfunctions and infections which had occurred during the follow-up period were within 6 months and 2 months after surgery, respectively. There was no shunt-related mortality. These chronological data should be considered in the planning of follow-up schedules.

Follow-up results after stent placement in failing arteriovenous shunts: A three-year experience

Self-expandable endoprostheses were used in 18 failing arteriovenous shunts after unsuccessful balloon dilatation. Technical success was satisfactory with an early patency in 17 of 18 shunts. Thrombosis right after stenting occurred in three shunts but was successfully treated in two. Follow-up history revealed recurrent events of reobstruction due either to stent or shunt stenoses or thrombosis. Restenosis within the stented segment was responsible for reobstruction in about half the cases. Although patency was low with 27% at 18-month follow-up, repeated intervention established a shunt survival rate of 77% at 18-month follow-up. Stent placement in AV shunts is useful for overcoming acute problems of balloon dilatation but does not prevent restenosis.