A.G. Melikyan, N.V. Arutyunov, A.E. Korshunov
Burdenko Research Neurosurgical Institute of the Russian Academy of Medical Science, Moscow, Russia
Introduction. Endoscopic third ventriculostomy (ETV) has gained much popularity and is considered to be an operation of choice in cases with obstructive hydrocephalus. It is characterized by high efficacy and rare complications, especially when compared with conventional shunting interventions. However, it should be mentioned, that the majority of reports, devoted to ETV results, is based on series of heterogeneous studies, which are not very numerous. As a rule, they deal with the nearest postoperative period, underestimate complications and mix two notions: ETV, performed physically, and clinically successful ETV.
Materials and Methods. ETV was performed in 188 cases, aged 4 months-67 years. They had active hydrocephalus. It was caused by occlusion at the aqueduct level with a typical pucture of the so-called triventriculomegaly in the majority of patients. Tumors of midbrain or a pineal area were watched in 113 cases; idiopathic or postinflammatory stenosis of the aqueduct was present in 65 patients. Occlusion was conditioned by a mass within the limits of the posterior cranial fossa in 10 cases. The operations were performed by 4 different surgeons with application of rigid endoscopes and standard ETV, described in medical literature. Catamnesis was obtained in 90 cases, followed during 2-5 months. Estimation of results of clinical, neuropsychological and rentgenologic examinations (in particular, MRI sequences, sensitive to liquor flow) was carried out for revealing ventriculostomy efficacy. Besides, clinical data, surgical protocols and videocassettes, containing visual information on operations, were analyzed retrospectively with the purpose of elucidating causes of complications and subsequent failures.
Results. There were no fatal outcomes after ETV. The nearest result with convincing regression of symptoms of intracranial hypertention turned out to be excellent in 175 cases (90%). ETV was ineffective in 13 patients. It was caused by quick obliteration (within 2 months) of ventriculostoma (5 cases), operation discontinuity because of bleeding (3 cases) and technical errors (5 cases). We had to implant shunting systems in the majority of cases and performed repeated and successful ETV in one patient. Relapse of symptoms of intracranial hypertension was watched in another 12 cases; it happened after a period of clinical well-being and against a background of MRI-patent ventriculostoma. Reoperations were made in 10 patients; they consisted in implantation of valve shunts. Repeated ETV was performed in 1 case; 1 patient did not give his consent to the operation. Thus, the total rate of unsuccessful procedures, including an early mechanical failure and its more remote hydrodynamic variety, was 13% (25 cases). Complications were observed in 25 patients. The most frequent of them was aseptic ventriculitis (12 cases). ETV was accompanied by intracranial hemorrhages of different severity in 6 patients (asymptomatic hemorrhage - 3, hematoma, demanding craniotomy and evacuation - 3). Liquorrhea from a wound (4 patients) and transient diabetes insipidus (2 cases) were rather rare. One case developed Parinaud's syndrome and paresis of the trochlear nerve after ETV. It was conditioned by a preceding unsuccessful attempt of endoscopic plasty of the stenosed aqueduct, rather than ETV proper. Retrospective analysis of videocassettes with records of operations showed, that an early mechanical failure of ventriculostoma was caused, as a rule, by incomplete fenestration of Lilliquist's arachnoid membrane in the interpeduncular cistern or marked hemorrhage. The second complication often predetermined the first one. Difference in the rates of efficacy and complications, reported by various surgeons, was insignificant. At the same time, a teaching curve was indicative of gradual reduction of failures with accumulation of their personal experience. Causes of a hydrodynamic (functional) failure, which usually develops later, are not clear and can reflect a progressive change of elastic properties of brain tissue in these patients.
Conclusions. ETV is a safe and highly effective method of treatment of active obstructive hydrocephalus. Well-considered indications, combined with refined surgical technique, are a prerequisite of reliable and permanent control of symptoms of intracranial hypertension.