Overdrainage in the treatment of hydrocephalus]

In infants or children, hydrocephalus is usually the consequence of an obstacle in the cerebro-spinal fluid (CSF) pathways and is most frequently treated by the insertion of a ventriculo-peritoneal shunt (rarely ventriculo-atrial). The CSF flow through such a shunt is equal to the ratio of the difference (DP) between the CSF input and output pressures over the valve resistance. When the child is in the upright position, a DP increase occurs due to the height of the hydrostatic column between the inlet and the shunt outlet. Thus if the shunt drains correctly in the prone position, it overdrains in the upright position. As the CSF flow through the shunt in standing patients is higher than the CSF secretion, the excess fluid will be taken out of the ventricles, resulting in pericerebral collections, slit ventricles or post-shunt craniostenoses. Many different techniques have been proposed to reduce overdrainage. The Orbis-Sigma shunt was designed in the "Service des Enfants-Malades" precisely for this purpose. In the upright position this shunt becomes a flow regulator and thus reduces overdrainage. Its use has decreased by 2-fold the number of mechanical complications related to overdrainage.     

Experience with a new concept to lower non-infectious complications in infants with programmable shunts.

In neonates and infants less than 1 year of age who are treated with a ventriculo-peritoneal shunt, non-infectious complications are almost as frequent and dangerous as infectious complications. While the incidence of infections can be reduced, using perioperative antibiotics, special surgical techniques and postoperative care non-infectious complications such as wound break-down, cerebrospinal fluid (CSF) fistula and subcutaneous CSF collection are preventable, but seem difficult to manage, especially in the group of patients at a susceptible age. The authors present their experience with the programmable Hakim valve in 40 neonates and infants less than 1 year of age, who were treated with de novo implantation of a ventriculo-peritoneal shunt due to various pathologies. The uneventful wound healing during the first weeks after shunt implantation, avoiding the above mentioned non-infectious complications, was supported by initial, temporary overdrainage and readjustment of the programmable valve after completed wound healing. All patients tolerated this procedure well and showed no pathological signs or symptoms of overdrainage like premature closure of cranial sutures, clinical low-pressure syndrome, slit ventricle syndrome (SVS), subdural fluid collection or brain collapse during an average follow-up period of 2.6 years (2 - 65 months). Infectious and other mechanical, non-infectious complications were analysed as well during the follow-up period. These results suggest that an initial, temporary overdrainage in infants and neonates with shunted hydrocephalus may contribute to further lower the incidence of non-infectious complications like wound break-down, CSF-fistula or subcutaneous CSF accumulation, without negative side effects. This technique could be a valuable option in the regimen of shunt-treatment of this age group in order to optimise the overall success rate and lower the general complication rate.     

What is the ideal initial valve pressure setting in neonates with ventriculoperitoneal shunts?

In order to determine the optimal valve pressure setting during the first weeks in neonates after implantation of programmable Hakim valves and to analyze the benefits and possible side effects of a new treatment protocol in this age group, we performed this prospective study. In 20 consecutive newborns less than 5 weeks of age with hydrocephalus due to various etiologies, a ventriculoperitoneal shunt with a programmable Hakim valve at an extremely low initial valve pressure setting of 30-40 mm H(2)O was implanted. This "overdrainage" was maintained, monitored by regular clinical examination and transcranial ultrasonographic imaging, until the wound healing was uneventfully completed and the permanent valve pressure setting of 100-120 mm H(2)O was chosen. In this age group, which is prone to specific noninfectious shunt complications like wound breakdown, cerebrospinal fluid (CSF) fistula and subcutaneous CSF collections, none of these complications were seen, nor were there any persisting overdrainage phenomena on transcranial ultrasonography. Initial, temporary "overdrainage" represents a simple, useful and risk-free therapy in neonates with programmable shunts which might lower the incidence of typical noninfectious complications in this age group.     

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.     

Long-term follow-up data from the Shunt Design Trial

Background: A previously reported multicenter randomized trial assessed whether 2 new shunt valve designs would reduce shunt failure rates compared to differential pressure valves. The study did not show a significant difference in the time to first shunt failure. Patients entered the trial between October 1, 1993, and October 31, 1995. The primary results were based on the patients' status as of October 31, 1996 (a minimum follow-up of 1 year). This report describes the late complications based on the patients' most recent follow-up. Methods: Three hundred and forty-four hydrocephalic children at 12 North American and European centers were randomized to 1 of 3 valves: a standard differential pressure valve; a Delta valve (PS Medical-Medtronic) or a Sigma valve (NMT Cordis). Patients were followed until their first shunt failure. Shunt failure was defined as shunt surgery for obstruction, overdrainage, loculation or infection. If the shunt did not fail, follow-up was continued until August 31, 1999. Results: One hundred and seventy-seven patients had shunt failure. Shunt obstruction occurred in 131, overdrainage in 13, loculated ventricles in 2 and infection in 29. The overall shunt survival was 62% at 1 year, 52% at 2 years, 46% at 3 years, 41% at 4 years. The survival curves for the 3 valves were similar to those from the original trial and did not show a survival advantage for any particular valve. Conclusions: Prolonged follow-up to date does not alter the primary conclusions of the trial: there does not appear to be one valve that is clearly the best for the initial treatment of pediatric hydrocephalus.     

CSF shunt failure with stable normal ventricular size

OBJECTIVE: The purpose of this study was to review the clinical features of a group of patients in whom ventricular enlargement was not a manifestation of prolonged CSF shunt obstruction. RESULTS: Twelve patients who had prolonged symptoms consistent with CSF shunt failure and stable normal ventricular size were demonstrated at the time of surgery to have obstruction of their CSF shunts. CONCLUSION: Ventricular enlargement is a common but not sine qua non indicator of CSF shunt failure, even after weeks or months of elevated intracranial pressure, and therefore cannot be relied upon for the diagnosis of CSF shunt failure. Although an increase in ventricular size is usually seen relatively early in the course of shunt malfunction, stable normal ventricular size in patients with symptoms and signs that are consistent with shunt failure can delay the diagnosis with potentially serious adverse consequences.     

Mechanical complications in shunts.

A retrospective study was conducted on 1,719 hydrocephalic patients, treated between 1974 and 1983 at the Hospital for Sick Children (Toronto) and l'H?pital des Enfants Malades (Paris), in order to better understand shunt failure. The statistical analysis demonstrates the following: (1) A probability of occurrence of shunt malfunction of 81% at 12 years of follow-up. (2) A high prevalence of shunt obstruction (56.1% of all malfunction) and fracture or disconnection of the tubings (13.6%). (3) A higher risk of proximal occlusion with flanged ventricular catheter. (4) Less malfunction with proximal-non-slit valves as compared to distal-slit valves. (5) The importance of pressure-flow characteristics of the shunt; because of an indirect relation between overdrainage and proximal occlusion. (6) A correlation between connectors and migration or fracture of the shunt. (7) Less distal obstructions when an open-ended distal-catheter was used. These complications were of some clinical, psychological and economical consequences. Their rate could be lowed.     

A case of cerebrospinal fluid eosinophilia associated with shunt malfunction

A 3-month-old female patient presented with a meningomyelocele at the lumber region associated with congenital hydrocephalus. She underwent ventriculoperitoneal (V-P) shunt surgery using the Sophy system. The shunt system was replaced due to a malformation. Following replacement, the patient presented with cerebrospinal fluid (CSF) eosinophilia at the age of 8 months. The eosinophilic granulocytosis of the CSF improved dramatically following systemic prednisolone administration. CSF eosinophilia without accompanying inflammation or pyrexia in the present case may have resulted from an allergic response to a foreign material such as the silicone tube pressure valve of the Sophy system or the sutures rather than bacterial or fungal infection. Based on our results, we believe that some patients may experience CSF eosinophilia following postoperative V-P shunt due to an allergic reaction to the shunt equipment. Prompt steroid treatment can produce spontaneous regression in such cases.     

Ventriculosubgaleal shunts for posthemorrhagic hydrocephalus in premature infants

OBJECTIVE: The early management of posthemorrhagic hydrocephalus in premature infants is challenging and controversial. These infants need a temporary cerebrospinal fluid (CSF) diversion procedure until they gain adequate weight, and the blood and protein levels in CSF are reasonably low before permanent shunt can be placed. Various options are available with their associated advantages and disadvantages. Ventriculosubgaleal shunts have been recommended as a more physiologic and less invasive means of achieving this goal. We have performed this procedure in 6 premature infants to evaluate their effectiveness and complications. METHODS: Six consecutive premature infants with posthemorrhagic hydrocephalus underwent placement of ventriculosubgaleal shunts over a 1-year period of time. We reviewed their clinical and imaging progress to assess the ability of the shunt to control hydrocephalus and the complication rates. RESULTS: In all 6 patients, the ventriculosubgaleal shunt controlled the progression of hydrocephalus as assessed by clinical and imaging parameters. A permanent shunt was avoided in 1 patient (16.6%). However, 4 patients developed shunt infections, 1 involving the ventriculosubgaleal shunt itself, and 3 immediately after conversion to ventriculoperitoneal shunt. The total infection rate of the series was 66.6%. All infections were caused by staphylococcus species. There was only a 1% shunt infection rate in our institution for all nonventriculosubgaleal shunts during the same period of time. CONCLUSION: Placement of ventriculosubgaleal shunts for interim CSF diversion in neonates with posthemorrhagic hydrocephalus is effective as a temporary method of CSF diversion. However, our experience has shown that it is associated with a unacceptably high CSF infection rate. A potential cause for infection is CSF stasis just beneath the extremely thin skin of the premature infants, promoting colonization by skin flora. CSF sampling before conversion to a permanent shunt and replacement of the proximal hardware, which has been in situ for a prolonged period, may decrease the infection rates. At present, the procedure is no longer performed at our institution.     

Sonographic position and functional diagnosis of ventricular positioned shunt systems in infants with hydrocephalus

By cranial sonography through the open fontanelles of infants with hydrocephalus a diagnosis of position and function of ventricular shunts is possible. A malposition of the ventricular catheter was diagnosed sonographically in 11 of 55 patients after primary shunting. Complications after shunting as overdrainage or shunt insufficiency could be demonstrated early and reliable. Controls in due course are diagnostically important. The number of computerized tomographies in infants with hydrocephalus can be reduced significantly. In order to reduce complications after shunting an intraoperative sonographical control of catheter position is intended.     

Treatment of recurrent ventriculoperitoneal shunt failure associated with persistent cerebrospinal fluid eosinophilia and latex allergy by use of an "extracted" shunt

Shunt failure is commonly associated with infection or mechanical obstruction of the shunt system. The presence of eosinophilia in the cerebrospinal fluid (CSF) has been associated with CSF shunt failure and may be related to both latex and shunt allergies. The authors describe the case of a child with a latex allergy who presented with 10 episodes of shunt failure over a period of 93 months. Cerebrospinal fluid sampling demonstrated persistent eosinophilia (3-36%) and negative cultures. Pathological examination of the ventricular catheter on 3 occasions demonstrated mechanical obstruction by inflammatory debris consisting largely of eosinophils and multinucleated giant cells. On the suspicion that the child might have some uncharacterized allergy to the shunt hardware, shunt replacement was performed using an "extracted" shunt system. The child has remained free of shunt malfunction for > 2 years since the last surgery. Immune responses to unpolymerized silicone are discussed.     

Thalamic glioblastoma with cerebrospinal fluid dissemination in the peritoneal cavity

Glioblastoma multiforme is one of the commonest primary malignant tumours of the brain with rare incidence of extracranial metastases. Systemic dissemination via the CSF or CSF diversionary shunt procedures is also rare. The reported 9-year-old child was a case of thalamic glioblastoma with hydrocephalus who underwent biventriculoperitoneal shunting before tumour decompression and radiotherapy. The child developed incapacitating ascites 8 months following surgical decompression and 9 months after the shunt diversion which was found to be caused by CSF dissemination of the glioblastoma via the ventriculoperitoneal shunt. The child ultimately succumbed to his disease.     

Cerebrospinal fluid penetration and bacteriostatic activity of linezolid against Enterococcus faecalis in a child with a ventriculoperitoneal shunt infection

We report a 4-year-old girl with a complicated Enterococcus faecalis ventriculoperitoneal shunt infection who failed vancomycin therapy. We demonstrate linezolid's high CSF penetration and its CSF bacteriostatic activity against E. faecalis. Linezolid may be a good alternative for treatment of ventriculoperitoneal shunt infections in cases of vancomycin-resistant organisms or apparent treatment failures.     

Broviac ventriculostomy for long-term external ventricular drainage.

A closed external ventricular drainage system that incorporates a Broviac catheter, with its dacron cuff, is described and its use is detailed. This device has been placed in 17 patients who have undergone 19 procedures. Indications for prolonged cerebrospinal fluid (CSF) drainage were: CSF leak (1 child) and shunt infection (16 children). Drainage was maintained for an average of 19 days, with a range of 6-47 days. The child with the CSF leak had resolution of this problem after 15 days, whereupon the system was removed. Thirteen of the 16 patients with shunt infections eventually underwent shunt placement. Two of the children in this group developed a shunt infection unrelated to their original septic episode that required placement of a second Broviac ventriculostomy. Two of the 3 children who did not undergo permanent shunt placement expired from other causes. Both of these children had clinically functioning Broviac ventriculostomies and culture-proven sterile CSF at the time of death. The remaining child with an infected shunt died of overwhelming sepsis. Complications included: ventricular catheter revision (4 cases), irrigation of the system (4 cases), and secondary CSF infection (1 case). The infection attack rate was 1 in 361 patient-catheter days, or 2.77/1,000 patient-catheter days. The advantages of the Broviac ventriculostomy are two. First, this system is highly resistant to infection. Second, the device is difficult to dislodge.     

Ventriculo cholecystic shunt in the management of hydrocephalus

Ventriculo peritoneal shunt is the preferred surgical management for hydrocephalus. Various sites namely cardiac atrium, pleural cavity, ureter, fallopian tubes, bladder and gastric lumen have been used as alternative for distal CSF flow. Gallbladder has been used sparingly in the past as a reservoir of CSF diversion. We report our experience with ventriculo-cholecystic (VC) shunt in 2 cases and recommend it as a simple and safe alternative .for CSF drainage particularly in the situations where serosal surface of abdomen is unfit or unavailable for absorption.     

Subdural empyema complicating cerebrospinal fluid shunt infection.

Subdural empyema has not been reported previously as a complication of cerebrospinal fluid (CSF) shunt surgery. An infant submitted to CSF shunt insertion for congenital hydrocephalus developed subdural empyema after a failed attempt to treat a superficial scalp wound infection with oral antibiotics. Enterobacter cloacae was isolated from the empyema. Temporizing management of the preceding superficial wound infection with oral antibiotics probably was the cause of this exotic pathogen. The treatment of infected scalp wounds contiguous with shunt hardware must be surgical.     

Life expectancy of ventriculosubgaleal shunt revisions

The subgaleal shunt has been and is currently used for the temporary bypass of the normal cerebrospinal fluid (CSF) pathways. We retrospectively reviewed all subgaleal shunts placed at the Children's Hospital, Birmingham, Ala., USA, from 1993 to the present and examined the life expectancy of revisions of this temporary method of CSF diversion. The average length of survival of primary, secondary and tertiary subgaleal shunts in this population was 37.4, 32.4 and 19.6 days, respectively. This current review demonstrates that the majority of patients in whom a subgaleal shunt is utilized may continue to obtain therapeutic diversion of their CSF for greater than 2.5 months with intermittent subgaleal shunt revisions. In the majority of cases, this length of time is sufficient to manage and resolve issues that would make ventriculoperitoneal shunting undesirable.     

The delta valve: how does its clinical performance compare with two other pressure differential valves without antisiphon control?

OBJECTIVE: The Delta valve is a pressure differential valve with a siphon control device. The valve mechanism is normally closed, but is designed to open in response to positive ventricular pressure, thereby avoiding overdrainage of cerebrospinal fluid (CSF). As a result, the incidence of subdural fluid collections as well as postural symptoms is purportedly reduced. In addition, the valve might reduce the number of obstructions as there would be no negative pressure sucking tissue and debris into the shunt system. In order to assess whether use of the Delta valve reduced the number of shunt-related problems as compared with two other pressure differential valves without an antisiphon component, we performed a retrospective review of all children undergoing CSF diversion procedures at our institution. METHODS: We reviewed the charts of 1, 193 patients. Cases included 2,325 ventriculoperitoneal (V-P) shunt insertions or revisions from January 1, 1985, to December 31, 1994, performed at our institution. The Delta valve and two pressure differential valves without antisiphon function were exclusively inserted during the following time periods: Holter-Hausner (H-H): January 1, 1985, to August, 1987; Heyer-Schulte (H-S): August, 1987, to June, 1991, and Delta: June, 1991, to December 31, 1994. RESULTS: Of the cases reviewed, 475 patients underwent insertion of a V-P shunt at the Childrens Hospital of Los Angeles and had a total of 686 shunt operations. Median follow-up was 3 years and ranged up to 10 years. Kaplan-Meier analysis documented that 67% of H-H, 71% of H-S and 70% of the Delta valves were functioning at 1-year follow-up. At 2-year follow-up, 66% of H-H, 64% of H-S and 65% of the Delta valves were functioning. The difference was not statistically significant. The occurrence rate for symptomatic subdural fluid collections was 0.7% (1/130) for H-H, 2.2% (3/139) for H-S and 1.0% (2/206) for the Delta valve (p = 0.52). The combined breakage/obstruction rate for the series was 7.7% (10/130) for H-H, 2.9% (4/139) for H-S and 4.9% (10/206) for the Delta valve (p = 0.19). No Delta valves malfunctioned secondary to fibrous capsule affecting the antisiphon device. CONCLUSIONS: In conclusion, it appears that performance of the Delta valve was not significantly different from the H-H and H-S valves, two valves without an antisiphon device. There was no significant difference in the occurrence of symptomatic subdural fluid collections based upon valve type, or in the combined valve breakage/obstruction rates based upon valve type.     

Lumboperitoneal shunting as a treatment for slit ventricle syndrome

OBJECTIVE: Slit ventricle syndrome (SVS) has been described in hydrocephalus patients who continue to have shunt malfunction-like symptoms in the presence of a functioning shunt system and small ventricles on imaging studies. These symptoms usually present years after shunt placement or revision and can consist of headache, nausea and vomiting, lethargy and decreased cognitive skills. Treatments offered range from observation, medical therapy (migraine treatment) and shunt revision to subtemporal decompression or cranial vault expansion. We describe a subset of patients with SVS who were symptomatic with high intracranial pressure (ICP) as measured by sedated lumbar puncture and whose symptoms completely resolved after lumboperitoneal shunt (LPS) placement. METHODS: Seven patients with a diagnosis of SVS underwent lumboperitoneal shunting. The age at shunting ranged from 3 to 18 years. Most had undergone recent ventriculoperitoneal shunt (VPS) revisions for presentation of shunt malfunction-like symptoms. Despite this, all remained symptomatic and underwent a sedated lumbar puncture to measure opening pressure (OP). All had high OP in spite of a functional VPS and underwent LPS placement. RESULTS: All 7 patients had a prolonged period of overdrainage symptoms after lumboperitoneal shunting that resolved completely over several weeks. The initial etiology of hydrocephalus was reported to include trauma, aqueductal stenosis and intraventricular hemorrhage of prematurity. Two patients required revision of their LPS, after which their symptoms again resolved. CONCLUSION: In a certain subset of patients with SVS who are symptomatic from increased ICP, placement of an LPS is an effective treatment option. It appears that this subgroup of patients previously treated with ventriculoperitoneal shunting behave in a fashion similar to pseudotumor cerebri patients and respond well to lumboperitoneal shunting.     

Repeat cerebrospinal fluid shunt infection in children

BACKGROUND: In this study, we investigated the treatment of cerebrospinal fluid (CSF) shunt infection and the risk factors for repeat shunt infection (RSI) in a cohort of children treated at the Hospital for Sick Children, Toronto, Canada. METHODS: Between 1996 and 2000, a total of 51 children were identified with shunt infection (mean age 5.8 years). The medical records of these children were reviewed to identify cases of RSI within 6 months of the initial shunt infection (ISI). RESULTS: In the 51 ISIs, the infecting organisms were coagulase-negative Staphylococcus (43.1%), Staphylococcus aureus (37.3%) and others (19.6%). The initial mode of treatment of the shunt infection was using an external ventricular drain (EVD) with removal of the shunt apparatus (54.9%), externalization of the shunt (37.3%) or shunt removal only (7.8%). The mean number of days of external CSF drainage (either EVD or externalized shunt) was 11.2 days. Ten patients (19.6%) developed RSI. The actuarial risk of RSI plateaued after 90 days at 24.4%. The following variables were tested as risk factors for RSI using survival analysis, although none reached statistical significance: initial organism (p = 0.09), age (p = 0.42), etiology of hydrocephalus (p = 0.45), number of days of CSF drainage (p = 0.45), type of surgical treatment of the ISI (p = 0.58) and the presence of bacteriologically positive CSF at ISI (p = 0.85). CONCLUSIONS: The risk of RSI is substantial and greater effort needs to be directed towards understanding the risk factors. Such studies will need a greater sample size in order to obtain sufficient statistical power.