Alfredo Puca

Cerebrospinal fluid shunting for hydrocephalus in the adult: Factors related to shunt revision

Cerebrospinal fluid shunting procedures are widely employed in the treatment of hydrocephalus and other disturbances of the dynamics of cerebrospinal fluid. In spite of its popularity, this operation frequently requires surgical revision. A retrospective analysis of a series of 356 adults who underwent the insertion of a cerebrospinal fluid shunt between January 1970 and December 1988 was performed. The incidence of revision was analyzed, and an attempt was made to identify possible causal factors. The overall incidence of surgical revisions was 28.65%; the number of revisions in the same patient ranged between one and eight. The most frequent causes of revision were distal malposition, obstruction, and infection. A statistically significant difference (P less than 0.05) was found in both the risk of revision in patients who had undergone previous operations and those who had not and in the incidence of revision before and after January 1985. Meticulous surgical technique as well as perioperative antibiotic prophylaxis appear responsible for the latter. The differences in the incidence of revision among patients treated with different types of shunts and valves, though remarkable, is not statistically significant.

Single nucleotide polymorphisms associated with sporadic brain arteriovenous malformations: where do we stand?

Brain arteriovenous malformations are characterized by a tangle of abnormal vessels directly shunting blood from the arterial to venous circulation. They are known to occur either sporadically or in the context of well-defined genetic disorders. Haemorrhage represents the most severe clinical manifestation, whereas other common symptoms include headache, seizures and neurological deficits. Although sporadic forms do not recognize a specific genetic cause, in recent years, it has been hypothesized that genes involved in angiogenesis and inflammation or coding for proteins, such as fibronectins, laminins and integrins, may play a role in the pathophysiology of brain arteriovenous malformations. More recently, a new trend of genetic studies has investigated the association between sporadic arteriovenous malformations and single nucleotide polymorphisms, single base variations between genomes within members of a biological species or between paired chromosomes in an individual, which may determine the susceptibility to develop complex diseases and influence their natural history. Several polymorphisms in two different families of genes have been associated with disease susceptibly and increased haemorrhagic risk. These genes are mainly involved in the inflammatory cascade and in the regulation of angiogenesis. However, most of the investigated polymorphisms have been selected on the basis of candidate genes because of their potential functional role in the pathogenesis of brain arteriovenous malformations or in other cerebrovascular diseases. Only one hypothesis-free genome-wide association study in a small number of patients has been performed so far, but it was unable to identify significant associations between brain arteriovenous malformations and specific genetic loci. In this article, we review and analyse the polymorphisms investigated to date in association with sporadic brain arteriovenous malformations in the medical literature. We discuss the biological, pathophysiological and clinical implications of these studies, with particular attention to the prediction of haemorrhagic risk and the possibility of building genetic profiles capable of defining the architectural features of the malformations and predict their evolution and natural history. We also present a joint analysis of the risk estimates found by the studies in literature that have evaluated the association between single nucleotide polymorphisms and brain arteriovenous malformation susceptibility and risk of bleeding. This analysis shows a statistically significant association between the interleukin 6 -174G>C (odds ratio = 1.97; 95% confidence interval: 1.15-3.38) and the tumour necrosis factor α -238G>A (odds ratio = 2.19; 95% confidence interval: 1.25-3.83) gene polymorphisms and risk of intracranial haemorrhage and between the activin-like kinase 1 (also known as ACVRL1) intervening sequence 3 -35A>G (odds ratio = 2.42; 95% confidence interval: 1.54-3.8) gene polymorphism and disease susceptibility.

In vivo carotid artery closure by laser activation of hyaluronan-embedded gold nanorods

We prove the first application of near-infrared-absorbing gold nanorods (GNRs) for in vivo laser closure of a rabbit carotid artery. GNRs are first functionalized with a biopolymeric shell and then embedded in hyaluronan, which gives a stabilized and handy laser-activable formulation. Four rabbits undergo closure of a 3-mm longitudinal incision performed on the carotid artery by means of a 810-nm diode laser in conjunction with the topical application of the GNRs composite. An effective surgery is obtained by using a 40-W/cm(2) laser power density. The histological and electron microscopy evaluation after a 30-day follow-up demonstrates complete healing of the treated arteries with full re-endothelization at the site of GNRs application. The absence of microgranuloma formation and/or dystrophic calcification is evidence that no host reaction to nanoparticles interspersed through the vascular tissue occurred. The observation of a reshaping and associated blue shift of the NIR absorption band of GNRs after laser treatment supports the occurrence of a self-terminating process, and thus of additional safety of the minimally invasive laser procedure. This study underlines the feasibility of using GNRs for in vivo laser soldering applications, which represents a step forward toward the introduction of nanotechnology-based therapies in minimally invasive clinical practices.

A comment on impaired peri-nidal cerebrovascular reserve in seizure patients with brain arteriovenous malformations

Sir, We read with great interest the article by Fierstra et al . (2011), recently published in your journal. This article reopens the debate regarding the unsolved problem of the origin of seizures in patients with brain arteriovenous malformations, the pathophysiology of which remains poorly understood. Although angiographic studies have shown some associations between different brain arteriovenous malformation angioarchitectural features and epilepsy, they have not elucidated the underlying pathophysiology (Turjman et al ., 1995 a , b ; Hoh et al ., 2002). Similarly, MRI studies have often shown gliosis and chronic ischaemic changes in peri-nidal tissue as well as in remote regions, but any significant correlation has been demonstrated between extent of gliosis and clinical symptoms (Essig et al ., 2000). The main pathophysiological hypotheses to date include: (i) focal cerebral ischaemia attributable to a steal phenomenon as described by Spetzler et al . (1992) and Taylor et al . (2002); (ii) gliosis, demyelination and haemosiderin deposits in peri-nidal tissue; and (iii) secondary epileptogenesis in ipsilateral temporomesial cortex (Yeh et al ., 1990), or at a distant site, attributable to a ‘kindling’ phenomenon, in which epileptic discharges are enhanced by excitatory synaptic connections from brain arteriovenous malformations (Hoh et al ., 2002). Bleeding was deemed responsible for triggering seizure activity by Turjman et al . (1995 a ) and Stein and Wolpert (1980); in contrast, in the study by Hoh et al . (2002), intracranial haemorrhage was not a statistically significant factor associated with epilepsy. Fierstra et al . (2011) studied in vivo the possible haemodynamic effect …

Intracranial epithelioid hemangioendothelioma: case report.

We report the case of a 27-year-old man who underwent surgical excision of an intracranial extra-axial right temporal lesion. A preoperative embolization with the use of a mixture of N-butyl-cyanoacrylate, ultrafluid-lipiodol, and micronized tungsten was necessary to devascularize the tumor. The histological diagnosis was epithelioid hemangioendothelioma. The patient was neurologically intact and tumor-free 18 months after surgery. To our knowledge, this is the fifth patient reported with intracranial epithelioid hemangioendothelioma and the first adult patient for whom complete data are available.

Evaluation of Fifth Nerve Dysfunction in 136 Patients with Middle and Posterior Cranial Fossae Tumors

One-hundred thirty-six patients operated on for extra-axial tumors of the posterior and middle cranial fossae were retrospectively evaluated to define the relevance of trigeminal nerve dysfunction and to correlate clinical and surgical observations. The following data are reported: tumor types, presence of specific trigeminal symptoms and signs, mean duration of symptomatology, anatomical relation between tumor and fifth nerve. Trigeminal symptoms were present in 45 subjects (33.08%) with a mean duration of 23.56 months. Frequency of symptoms was different in various oncotypes. Fifth nerve disturbances were the symptom of onset in 18 subjects (13.23%). A tumoral involvement of the nerve was reported at surgery in 73 patients (53.67%) and was defined as contact, compression or infiltration. Postoperatively, 12 patients showed an improvement of fifth nerve disturbances. A statistically significant difference (p < 0.05) was found in: (1) the incidence of symptoms in patients with and in those without anatomical trigeminal involvement: (2) the incidence of signs in the same groups; (3) the incidence of postoperative relief in patients with fifth nerve compression compared to patients with different surgical findings; (4) the incidence of postoperative relief in patients with typical trigeminal neuralgia compared to those with other symptoms.

Trigeminal involvement in intracranial tumours. Anatomical and clinical observations on 73 patients.

SummaryNeoplastic involvement of the trigeminal nerve was observed in 73 patients operated on in our institution for extra-axial tumours of the posterior and middle cranial fossae.It was defined as contact, compression, or infiltration. The nerve root was involved in 58 patients, the ganglion and/or the peripheral divisions in 9, all portions of the Vth nerve system in 6. A clinical trigeminal dysfunction was present in 44 patients (60%).Anatomico-surgical findings are correlated with clinical features and with tumour type. Typical trigeminal neuralgia was the complaint in 7 subjects; all of them presented an involvement of the sensory root.Post-operatively, 11 patients were relieved of their symptoms. The outcome is correlated with the anatomical findings and with the extent of surgical removal of the tumours.The importance of a careful evaluation of patients with trigeminal symptomatology is stressed.

Craniovertebral junction malformation and rotational occlusion of the vertebral artery

An unusual case of rotational occlusion of a non-dominant vertebral artery (VA) is presented. This clinical syndrome is associated for the first time with a complex craniovertebral junction malformation. Rotational occlusion of the VA is usually asymptomatic, vertebro-basilar insufficiency has been rarely observed in cases of involvement of a dominant VA, and concomitant occlusion or hypoplasia of the contralateral artery. Diagnosis of rotational VA occlusion is based on haemodynamic demonstration of the effects of head rotation.The importance of the awareness of this syndrome is stressed.An unusual case of rotational occlusion of a non-dominant vertebral artery (VA) is presented. This clinical syndrome is associated for the first time with a complex craniovertebral junction malformation. Rotational occlusion of the VA is usually asymptomatic, vertebro-basilar insufficiency has been rarely observed in cases of involvement of a dominant VA, and concomitant occlusion or hypoplasia of the contralateral artery. Diagnosis of rotational VA occlusion is based on haemodynamic demonstration of the effects of head rotation. The importance of the awareness of this syndrome is stressed.

Spontaneous Thrombosis of an Aneurysm of the Great Vein of Galen

A case of a thrombosed aneurysm of the vein of Galen in a 9-year-old boy is reported. Previously, only ten clotted aneurysms of the vein of Galen have been described. In our case, thrombosis occurred spontaneously after birth. Clinical presentation was characterized by signs of hydrocephalus, with an abrupt deterioration after several years of satisfactory clinical evolution. The patient was successfully treated with a ventriculoperitoneal shunt.

In vivo laser assisted microvascular repair and end-to-end anastomosis by means of indocyanine green-infused chitosan patches: a pilot study

Laser‐based repairing techniques offer several advantages respect to standard suturing in microsurgery. In this work we evaluate the applicability and feasibility of two innovative laser‐based approaches for microvascular repair and anastomoses: (1) laser‐assisted vascular repair (LAVR); (2) laser‐assisted end‐to‐end vascular anastomosis (LAVA). All these procedures have been executed by the use of diode laser irradiation and chitosan‐patches infused with Indocyanine Green (ICG).