Anesthesia for endoscopic ventriculostomy for the treatment of hydrocephalus: case report

Abstracts

JUSTIFICATIVA E OBJETIVOS: A terceiro-ventriculostomia endoscópica está se tornando um procedimento de rotina entre as intervenções neurocirúrgicas infantis. Entretanto, relatos sobre anestesia para crianças submetidas a tais procedimentos ainda são escassos. O objetivo desta série de casos foi demonstrar os cuidados e a eficácia do método empregado. RELATO DOS CASOS: Foram avaliadas retrospectivamente 38 crianças abaixo de 2 anos que se submeteram à terceiro-ventriculostomia neuroendoscópica para tratamento de hidrocefalia obstrutiva no período de 1999 a 2004 no Biocor Instituto. Foram estudados o diagnóstico, comorbidades, idade, peso, técnica anestésica, monitorização e as complicações intra e pós-operatórias. Todos os pacientes, entre 1 semana e 20 meses, apresentavam hidrocefalia obstrutiva por compressão do aqueduto de etiologia variada. A indução anestésica em 35 crianças foi por via inalatória e por via venosa em três delas. A monitorização de 34 pacientes foi com eletrocardiograma, oxímetro de pulso, capnógrafo e termômetro esofágico, sendo quatro crianças monitorizadas com pressão arterial invasiva contínua. A manutenção da anestesia em 15 pacientes foi balanceada com fentanil e isoflurano e em outros 23 pacientes inalatória com isoflurano. Trinta e cinco crianças foram extubadas após o procedimento na sala cirúrgica e outras três no CTI. Seis pacientes foram encaminhados ao CTI após a extubação. Complicações observadas: disritmias cardíacas sem repercussão hemodinâmica no intra-operatório (seis casos). Dois pacientes tiveram sangramento intra-operatório, mas somente um deles demandou implante de derivação ventricular externa. As complicações no pós-operatório foram: vômitos (6), picos febris (4) convulsões (2), laringoespasmo (1) e estridor laríngeo (1). CONCLUSÕES: A terceiro-ventriculostomia apresenta baixa incidência de complicações mesmo em pacientes com menos de 24 meses, desde que sejam adotadas técnicas anestésicas e cirúrgicas adequadas.

ANESTESIA, Pediátrica; CIRURGIA, Neurocirurgia; Doenças, Congênita

CLINICAL REPORT

Anesthesia for endoscopic ventriculostomy for the treatment of hydrocephalus. Case report^*

Anestesia para ventriculostomía por vía endoscópica para tratamiento de hidrocefalia. Relato de casos

Friederike Wolff Valadares^I; Michelle Nacur Lorentz, TSA^II; Eliana G. Heyden^III; José Aloysio Costa Val Filho^IV

^IAnestesiologista do Biocor Instituto; Doutora em Medicina pela Universidade de Aachen, Alemanha

^IIAnestesiologista do Biocor Instituto

^IIICoordenadora do Serviço de Anestesiologia do Biocor Instituto; Anestesiologista do Hospital da UNIMED

^IVCoordenador do Serviço de Neurocirurgia Pediátrica do Biocor Instituto

^{Correspondence to}

SUMMARY

BACKGROUND AND OBJECTIVES: Endoscopic third ventriculostomy is becoming routine among neurosurgical pediatric procedures. However, reports on anesthesia for children undergoing such procedures are rare. The aim of this series of cases was to demonstrate the precautions that should be taken and efficacy of the method used.

CASE REPORT: Thirty-eight children younger than 2 years, who underwent neuroendoscopic third ventriculostomy for the treatment of obstructive hydrocephalus from 1999 to 2004 at the Biocor Instituto were evaluated retrospectively. The diagnosis, comorbidities, age, weight, anesthetic technique, monitoring, and intra- and postoperative complications were evaluated. Patients, ages 1 week to 20 months, presented obstructive hydrocephalus secondary to compression of the aqueduct of different etiologies. In thirty-five children anesthesia was induced by inhalational anesthetics and in 3 by intravenous anesthetics. Thirty-four patients were monitored with electrocardiogram, pulse oxymeter, capnograph, and esophageal thermometer, while in 4 children it included also continuous invasive blood pressure monitoring. Fifteen patients had balanced maintenance anesthesia with fentanyl and isoflurane, and 23 children received inhalational isoflurane. Thirty-five children were extubated after the procedure in the surgical room and three in the ICU. Six patients were transferred to the ICU after extubation. The following complications were observed: intraoperative cardiac arrhythmias without hemodynamic repercussions (6 cases); two patients presented intraoperative bleeding, but in only one the placement of an external derivation was necessary. The postoperative complications included: vomiting (6), fever (4), seizures (2), laryngeal spasm (1), and stridor (1).

CONCLUSIONS: Third ventriculostomy has a low incidence of complications, even in patients younger than 24 months, as long as proper anesthetic and surgical procedures are used.

Key Words: ANESTHESIA, Pediatric; DISEASES, congenital: hidrocephalus; SURGERY, Neurosurgery: ventriculostomy.

RESUMEN

JUSTIFICATIVA Y OBJETIVOS: La tercero-ventriculostomía endoscópica se está convirtiendo en un procedimiento de rutina entre las intervenciones neuroquirúrgicas en niños. Sin embargo, relatos sobre anestesia para niños sometidos a esos procedimientos son escasos todavía. El objetivo de esta serie de casos fue demostrar los cuidados y la eficacia del método empleado.

RELATO DE LOS CASOS: Se evaluaron retrospectivamente 38 niños por debajo de 2 años de edad que se sometieron a la tercero-ventriculostomía neuroendoscópica para tratamiento de hidrocefalia obstructiva en el período de 1999 a 2004 en el Biocor Instituto. Se estudiaron el diagnóstico, comorbidades, edad, peso, técnica anestésica, monitorización y las complicaciones intra y postoperatorias. Todos los pacientes, entre 1 semana y 20 meses, presentaban hidrocefalia obstructiva por compresión del acueducto de etiología variada. La inducción anestésica en 35 niños fue por inhalación y por vía venosa en 3 de ellos. La monitorización de 34 pacientes fue con electrocardiograma, oxímetro de pulso, capnógrafo y termómetro esofágico, siendo 4 niños monitorizados con presión arterial invasiva continua. El mantenimiento de la anestesia en 15 pacientes fue balanceada con fentanil e isoflurano y en otros 23 pacientes inhalatoria con isoflurano. Treinta y cinco niños fueron extubados después del procedimiento en la sala quirúrgica y otros tres en el CTI. Seis pacientes fueron llevados al CTI después de la extubación. Complicaciones observadas: arritmias cardíacas sin repercusión hemodinámica en el intraoperatorio (6 casos). de los pacientes presentaron sangramiento intraoperatorio, pero solamente uno de ellos necesitó implante de derivación ventricular externa. Las complicaciones en el postoperatorio fueron: vómito (6), picos de fiebre (4) convulsione (2), laringoespasmo (1) y estridor laríngeo (1).

CONCLUSIONES: La tercero-ventriculostomía presenta una baja incidencia de complicaciones incluso en pacientes con menos de 24 meses, siempre que sean adoptadas las técnicas anestésicas y quirúrgicas adecuadas.

INTRODUCTION

Endoscopic neurological surgery in children is increasingly more frequent among the minimally invasive procedures ^1-3. Neuroendoscopic procedures give the physician a direct view of brain structures that are difficult to access during conventional craniotomy ⁴.

Although these procedures have been routine since the end of the 1990s, the reports in the literature on anesthesia in children undergoing neuroendoscopic surgeries are rare ^5,6. Among the techniques employed, third ventriculostomy has been used frequently in the treatment of obstructive hydrocephalus, found in increasing numbers in premature infants or in children with other severe diseases, because it eliminates the need for ventriculoperitoneal derivations ^2,7. However, despite being a minimally invasive technique, with low morbidity and mortality, it is not devoid of perioperative complications ^5,6,8-18, and the anesthesiologist should be knowledgeable on such matters. The aim of this study was to report and discuss the anesthetic conduct and perioperative complications of third ventriculostomy in a series of 38 children younger than 2 years.

CASE REPORT

Of the 300 endoscopic microsurgical procedures performed since 1997 in the Biocor Institute, 38 children younger than 2 years underwent third ventriculostomy for the treatment of obstructive hydrocephalus from 1999 to 2004.

The diagnosis, comorbidities, age, weight, duration of the surgery and anesthesia, anesthetic technique, monitoring, intra- and postoperative complications, and destination of the patients were evaluated.

All 38 children had non-communicating obstructive hydrocephalus secondary to compression of the aqueduct. The age of the patients ranged from one week to 20 months, with a mean of 7.2 ± 5.4 months.

The children weighed between 3 and 12 kg, with a mean of 6.7 kg. Eighteen children were females and 20 males. Patients were admitted the night before the procedure, when the pre-anesthetic evaluation was done.

The etiology of aqueduct compression varied: congenital stenosis of the aqueduct - 10, infection - 12 (7 neonatal septicemias, 4 infant meningitis and one intra-uterine toxoplasmosis infection), encephalic malformation - 14 (6 Dandy- Walker syndromes, 4 Arnold Chiari malformations, 2 arachnoid cysts, and 2 vascular malformations), and intraventricular hemorrhage - 4 (2 with neonatal septicemia). Analyzing the comorbidities: nine patients were premature (24 to 34 weeks), four patients presented meningomyelocele, and one patient had congenital cardiopathy (transposition of the great vessels) and agenesis of the spleen.

One unit of packed red blood cells and a pediatric ICU bed were reserved for every child. Patients did not receive pre-anesthetic medications.

A rigid ventriculoscope with an external diameter of 5 mm with 3 working channels (Fig. 1) was used for the surgeries. The procedure was performed through a frontal trepanation to the right and in front of the coronal suture after infiltration with 0.25% bupivacaine with vasoconstrictor (maximal dose of 2 mg.kg^-1) for analgesia and to reduce bleeding. After the dura mater was opened, the lateral ventricle was punctured with the ventriculoscope. Under direct view, the ventriculoscope was inserted through the foramen of Monro, and the structures of the third ventricle were identified. The floor of the third ventricle was opened after coagulation of the tuber cinereum and widened with a Fogarty catheter. A communication between the third ventricle and the pre-pontine cisterna was created, reestablishing the circulation of the cerebrospinal fluid. After the ventriculoscope was inserted, the surgical team and the anesthesiologist followed the procedure on a video screen.

The temperature of the surgical room was adequate (around 24°C). Patients were placed on dorsal decubitus with a 30°-elevation of the head, which was placed on a headrest. Patients were covered with a thermal blanket to avoid hypothermia. Routine and emergency drugs (atropine and adrenaline) were readily available in syringes with the proper dilutions. Monitoring in 34 patients consisted of esophageal temperature, electrocardioscope, pulse oxymeter, capnograph, and non-invasive blood pressure. In four patients monitoring included invasive blood pressure.

In 34 patients anesthesia was induced with inhalational sevoflurane. In two patients anesthesia was induced with intravenous thiopental, and the other two with propofol IV.

Peripheral venous access was established with the largest catheter possible, and the administration of intravenous fluids was aimed at maintaining normovolemia. Patients received prophylactic cefazoline. Vecuronium (9 patients) and atracurium (29 patients) were the neuromuscular blockers used. Fifteen patients received fentanyl to complement anesthesia. After tracheal intubation, anesthesia was maintained with isoflurane, and a time-cycle, pressure-controlled ventilator maintained ventilation. There was no need for blood transfusions. Patients received intravenous dypirone for analgesia in conventional doses at the end of the surgery. Thirty-five children were awakened and extubated in the surgical room and three were extubated in the pediatric ICU. Six children were transferred to the ICU after extubation. The length of anesthesia ranged from 60 and 135 minutes (mean of 106 minutes) and the duration of the surgery ranged from 20 to 60 minutes (mean of 39 minutes).

The following intraoperative complications were observed: six children (15.6%) presented cardiac arrhythmias without hemodynamic changes; five children (13%) had bradycardia (criterion: heart rate below 80 beats.min^-1)⁹; and one child (2;6%) presented tachycardia (criterion: heart rate above 150 beats.min^-1)⁹. Two patients (5.2%) had intraoperative bleeding. In one child, bleeding stopped after irrigation with Ringer's physiological solution. Only one child (2.6%) needed external ventricular derivation. In the postoperative period, six children (15.6%) had vomiting, four (10.4%) had fever, two (5.2%) had seizures, one (2.6%) had laryngeal spasm, and one (2.6%) patient with severe Arnold Chiari syndrome had stridor.

DISCUSSION

There are very few reports in the literature on neuroendoscopic procedures in children ^5,6.

A consensus on monitoring has not yet been achieved. Recommendations on blood pressure monitoring vary among non-invasive ⁸, invasive for complicated cases ⁵, and invasive for every procedure ^6,9,10. With increased experience and knowledge of the possible complications, the anesthetic conduct has changed toward more invasive monitoring, similar to any neurosurgical procedure in adults and in children ^6,9,15, especially in more complex neuroendoscopic procedures (tumor biopsy, cyst fenestration, etc) or when there is a change in the anatomy. In this study, invasive blood pressure monitoring was used only in specific cases, such as in one patient with meningomyelocele and risk for developing latex allergy ^19-21, change in the anatomy of a child with arachnoid cyst and in another with Dandy Walker syndrome, and in the child with congenital cardiopathy. The cardiac arrhythmias mentioned in this study did not cause hemodynamic changes; however, it should be mentioned that small, transient changes in blood pressure might have go unnoticed.

Neuroanesthesia conduct and technique used in children are different from those used in adults. Despite knowing the negative effects of high concentrations of volatile anesthetics under pressure on brain perfusion, several authors agree that inhalational induction should be used in children without venous access or when the use of pre-anesthetic medication is contra-indicated ^5,11-26. There is also no consensus on the most suitable maintenance technique. Total venous anesthesia, inhalational anesthesia, or combined anesthesia, which demand that the anesthesiologist be aware of the possible adverse effects that such techniques might pose on cerebral hemodynamics and their implications in patients with increased intracranial pressure, are mentioned ^5,22-26.

Taking into account the intraoperative complications (20.8%), we observed they were below the frequency described in the literature. In a recent study undertaken in Turkey with 210 children, 40% of them developed intraoperative cardiac arrhythmias ⁶. Besides tachycardia, there are reports in the literature of bradycardia, several cardiac arrhythmias, hypotension, hypertension, and even cardiac arrest ^8,9,12,13,18. All these events might occur after manipulating one of the delicate structures around the third ventricle (hypothalamus, brain stem). Besides direct stimulation, the causes may vary from a reduction in brain perfusion to ischemia of those structures secondary to an increase in intracranial pressure. Most are short-term changes, returning to normal parameters as soon as the balloon of the Fogarty catheter is deflated, the ventriculoscope is removed, and intracranial pressure returns to normal ^6,8. Determining the exact subjacent mechanism demands more detailed studies since several events are masked by general anesthesia. An adult patient undergoing third ventriculostomy under local anesthesia reported a painful sensation at the time the floor of the third ventricle was penetrated.

Venous or arterial bleeding is the most feared complication. The basilar artery is located under the floor of the third ventricle, being subjected to trauma by the catheter ^4-6,15, which many times leads to the placement of an external ventricular derivation. In this study, this happened to one of the patients due to bleeding of the perforating arteries. It can also be an indication to change the procedure to open craniotomy to eliminate the bleeding ¹⁰.

Besides those complications, there are repots in the literature of: diabetes insipidus, syndrome of inappropriate antidiuretic hormone secretion, paralysis of cranial nerves, especially III and VI, delayed awakening, transitory mental confusion, loss of memory, infection, hemorrhage, seizures, headache, pneumocephalus, and cardiorespiratory arrest ^8,14,15,17. Most postoperative complications observed were not related specifically to the procedure, such as vomiting ²⁷ and respiratory problems. The fever that affected four patients (10.4%) can be attributed to the blood retained in the ventricles. Two patients presented seizures. One of them was already being treated for chronic recurrent seizures with phenobarbital, and another presented focal seizures that were treated with anticonvulsivant drugs.

After the procedure, the children were under careful postoperative monitoring ². Twenty-four per cent of the patients were monitored for at least 24 hours in the pediatric ICU. Patients who presented intraoperative hemorrhage or other complications, or those who presented concomitant diseases (congenital cardiopathy) were transferred to the pediatric ICU. To avoid problems secondary to postoperative apnea, infants who were born premature, with a post-conception age below 60 weeks, were also transferred to the pediatric ICU ²⁸.

The procedures described show the importance of the anesthesiologist's knowledge of the particularities of the associated problems patients who undergo neuroendoscopic third ventriculostomy for the treatment of obstructive hydrocephalus might present.

REFERENCES

Submitted em 04 de abril de 2006

Accepted para publicação em 17 de outubro de 2006

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*

Received from Biocor Instituto, Belo Horizonte, MG

Publication Dates

• Publication in this collection
  19 Jan 2007
• Date of issue
  Feb 2007

History

• Received
  04 Apr 2006
• Accepted
  17 Oct 2006