Use of a micromanipulator system (NeuRobot) in endoscopic neurosurgery.

NeuRobot, a micromanipulator system with a rigid neuroendoscope and three micromanipulators, was developed for less invasive and telecontrolled neurosurgery. This system can be used to perform sophisticated surgical procedures through a small, 10-mm-diameter, window. The present study was performed to evaluate the feasibility of using NeuRobot in neuroendoscopy. Four different intraventricular neurosurgical procedures were simulated in three fixed cadaver heads using NeuRobot: (1) fenestration of the floor of the third ventricle; (2) fenestration of the septum pellucidum; (3) biopsy of the thalamus; and (4) biopsy of the choroid plexus of the lateral ventricle. Each procedure required less than 2 min, and all procedures were performed accurately. After these surgical simulations, a third ventriculostomy was carried out safely and adequately in a patient with obstructive hydrocephalus due to a midbrain venous angioma. Our results confirmed that NeuRobot is applicable to lesions in which conventional endoscopic neurosurgery is indicated. Furthermore, NeuRobot can perform more complex surgical procedures than a conventional neuroendoscope because of its maneuverability and stability. NeuRobot will become a useful neurosurgical tool for dealing with lesions that are difficult to treat by conventional neuroendoscopic surgery.

Comparison of three types of laryngoscope for tracheal intubation during rhythmic chest compressions: a manikin study.

BACKGROUND: If tracheal intubation can be performed during uninterrupted chest compressions, this will sustain circulation during the procedure of intubation and may lead to successful resuscitation. We compared three types of laryngoscope on a manikin as to whether they enabled tracheal intubation while the manikin's chest was rhythmically compressed. METHODS: A total of 35 persons who had little or no experience in intubation served as examinees. The laryngoscopes employed were a conventional Macintosh laryngoscope (MAC), a new video laryngoscope, Pentax-AWS (AWS) and an optic laryngoscope Airtraq (ATQ). During chest compression on the manikin by an assistant, the examinee attempted to perform intubation. The success rate and the time for successful intubation were measured. RESULTS: During rhythmic chest compressions, nine examinees failed in tracheal intubation with the MAC, seven failed with the ATQ, and no one failed with the AWS. The success rates with the AWS were significantly higher than those with the MAC (P<0.01) or ATQ (P<0.05). The time needed for intubation was significantly shorter with the Pentax-AWS than with the others. CONCLUSIONS: These results suggest that the use of the Pentax-AWS enables tracheal intubation while the patient's chest is rhythmically compressed, and would more often lead to successful intubation, which in turn may lead to more successful resuscitation.

Follow-up study of condylar bony changes using helical computed tomography in patients with temporomandibular disorder.

OBJECTIVES: We investigated condylar bone changes in 1032 joints from 516 subjects in order to clarify the incidence and type of bone changes in the temporomandibular joint (TMJ), and alteration of the change during follow-up, in patients with temporomandibular disorders (TMD). METHODS: We classified condylar bone change into five types on multiplanar reformatted (MPR) images of helical CT: N, no bone change; F, flattening; E, erosion with or without roughening; D, deformity; S, deformity accompanied by erosion with or without roughening. In 51 of 516 subjects, follow-up CT examination was performed and transition of condylar bone change was observed. RESULTS: Condylar bone change was seen in 617 (63.7%) of 1032 joints and in 70 (68.6%) of 102 follow-up joints. The number of joints of Types D and S increased at follow-up, but those of Types N, F and E decreased. CONCLUSION: In this study, the main direction of transition of condylar bone change in joints with TMD was absorptive bone change to absorptive with sclerotic (proliferative) bone change and further to sclerotic (proliferative) bone change. Our classification of condylar bone change was thought to be convenient for the evaluation of bone change in TMD.

Progressive wild-type transthyretin deposition after liver transplantation preferentially occurs onto myocardium in FAP patients.

To elucidate whether progressive wild-type transthyretin (TTR) deposition can actually occur after liver transplantation (LT), amyloid fibrils were investigated in two familial amyloid polyneuropathy patients with TTR Val30Leu variant, who died 1 year after LT. Amyloid fibrils were extracted from cardiac muscles, sciatic nerves and kidney, which were investigated by the immunoprecipitation-mass spectrometry method and liquid chromatography-ion trap mass spectrometry analysis. The ratio of wild-type to variant TTR in cardiac muscle was approximately 5:5 before LT, but greatly increased to about 9:1 after transplantation. The ratios in sciatic nerves and kidney obtained at autopsy were approximately 5:5. Wild-type TTR was undetectable in kidney amyloid obtained before LT. Our results indicate that paradoxical wild-type TTR deposition after LT can preferentially occur in myocardium, leading to fatal cardiac dysfunction, but it is quite likely that this phenomenon can also occur in other visceral organs.

Four cases of thrombotic events associated with neuro-endovascular therapy: heparin resistance and aspirin resistance.

SUMMARY: Thrombotic events are caused by insufficient antithrombotic treatment in endovascular surgery. We experienced four cases of thrombotic events and consider the factors from the point of view of heparin resistance and aspirin resistance. The proportion of these features is quite high and appropriate management is important.

Telecontrolled micromanipulator system (NeuRobot) for minimally invasive neurosurgery.

BACKGROUND: To perform less invasive neurosurgery, a telecontrolled micromanipulator system has been developed and applied to clinical situations. Basic experiments for telesurgery have also been conducted. METHOD: A cadaver head was used to carry out surgical simulation of the opening of the sylvian fissure and third ventriculostomy. After obtaining permission from the Ethical Committee of Shinshu University School of Medicine, part of the recurrent meningioma in a 45-year-old man was removed. As basic experiment for telesurgery, surgical simulation was also conducted in a rat brain with the operating console transported to a hospital 40 km distant from the University. FINDINGS: Opening of the sylvian fissure and third ventriculostomy were accurately performed. Tumour removal in a patient with recurrent meningioma was safely achieved. Surgical simulation in the rat brain was accurately and correctly carried out, operated on from a hospital 40 km distant. CONCLUSIONS: The NeuRobot, telecontrolled micromanipulator system, can be used as a tool for less invasive neurosurgery.

Pathological Result of Basilar Artery Stenosis Rapidly Progressed and Ruptured with Stent-assisted Angioplasty.

SUMMARY: Intracranial artery angioplasty utilizing coronary stent is now widely tried as an effective alternative for treating intracranial artery stenosis, and several successful result of stent-assisted angioplasty for intracranial artery were reported. Authors experienced a case of the basilar artery stenosis, in which re-stenosis progressed rapidly after simple balloon angioplasty and resulted in vessel rupture during stent-assisted angioplasty. Pathological result achieved by autopsy showed vessel wall disruption at the stent and multiple interruptions and defect of elastic laminar.

Comparison of condylar positions at intercuspal and reference positions in patients with condylar bone change.

The purpose of this study was to investigate the condylar displacement from intercuspal position (IP) to reference position (RP), using a jaw movement measuring system with 6 d.f. and helical computed tomography (CT). The 19 patients included in the present study were divided into a group with bilateral condylar bone change (10 subjects, including the sub-groups with flattening and osteophyte formation) and a group with no condylar bone change (9 subjects). The results showed that the bone change group had significantly more superior, posterior and absolute horizontal IP to RP slides than the no bone change group. There was also a significant difference in the amount of antero-posterior and supero-inferior condylar IP-RP displacements related to the type of condylar bone change within the bone change group. The osteophyte sub-group showed the largest posterior displacement, and the flattening sub-group showed the largest superior displacement. These results suggested that this large IP-RP difference in the bone change group might be related to their temporomandibular joint (TMJ) pathology, and it might therefore be useful to keep this difference in mind as one of the clinical indices suggesting the presence of TMJ osteoarthritis (OA).

Embolization of Arteriovenous Malformation. Efficacy and Safety of Preoperative Embolization Followed by Surgical Resection of AVM.

SUMMARY: Treatment options for cerebral arteriovenous malformation (AVM) are still controversial due to the recent result of stereotactic radiosurgery and the improved result of microsurgical resection. We investigated previously treated AVM cases and discussed the efficacy and safety of preoperative embolization especially for microsurgical resection of high-grade AVM in the Spetzler-Martin grading. Efficacy of preoperative embolization was evaluated based on 126 previously treated AVM cases at Shinshu University Hospital during the last 25 years. The safety of embolization was evaluated based on our previously-embolized 58 AVM cases (91 procedures) in the last 11 years after introduction of preoperative embolization for AVM. In all 126 cases, 82 were treated before introduction of embolization and 44 were treated after introduction of embolization. In 82 cases of the pre-embolization era, 63 lesions were removed totally in 63 AVMs (77%), partially resected in 11 (13%) and untreated in eight (10%). In 74 surgically removed cases, 11 (15%) cases showed severe intra/postoperative bleeding. In 44 cases of the embolization era, lesions were removed totally in 29 AVMs (66%), disappeared only with embolization in one (2%), disappeared with radiosurgery in seven (16%) and were untreated in five (11%). In 32 surgically removed cases, only one (2%) case showed severe intra/postoperative bleeding. In all 58 embolized cases, 44 were surgically removed, six were treated with radiosurgery, one was eliminated with embolization alone and six were partially obliterated and followed up for their location. In 91 procedures for 58 cases, two haemorrhagic and three ischemic complications occurred, three were transient and two remained having neurological deficits. The introduction of preoperative embolization improved the total removal rate and reduced the intra/postoperative bleeding rate in surgical removal of AVM. The total risk of embolization is low and well-designed preoperative embolization makes surgical resection safer even in high-grade AVM in the Spetzler-Martin grading.

Neurotrophic effect of hepatocyte growth factor on neonatal facial motor neurons.

The neurotrophic effect of hepatocyte growth factor (HGF) on axotomized facial motor neurons was examined after local application of HGF to the proximal facial nerve stump of the neonatal rat on post-natal day one (P1). Motor neuron survival was expressed as the neuronal cell count on the injured side as a percentage of that on the noninjured side. Motor neuron survival of the control group was 76% on P3, 54% on P5 and 23% on P8, that of the HGF-treated group 78% on P3, 69% on P5 and 31% on P8, and that of the brain-derived neurotrophic factor (BDNF)-treated group 91% on P5 and 45% on P8. The motor neuron survival rates were then adjusted by deducting the facial motor neurons corresponding to the uninjured retroauricular branch (20%) of the facial nerve. The adjusted values were 70% (P3), 42% (P5) and 4% (P8) for the control group, 72% (P3), 61% (P5) and 14% (P8) for the HGF-treated group, and 88% (P5) and 32% (P8) for the BDNF-treated group. These findings demonstrate that HGF has a neuroprotective effect on injured facial motor neurons and suggest that HGF has neurotrophic properties distinct from those of BDNF.

Thickness of the roof of the glenoid fossa and condylar bone change: a CT study.

OBJECTIVES: The aim of this study is to investigate the relationship between the thickness of the roof of the glenoid fossa in the temporomandibular joint (TMJ) and the existence and types of condylar bone change. MATERIALS AND METHODS: Helical CT was used to measure the thickness of the roof of the glenoid fossa at its thinnest part in 37 orthodontic patients with temporomandibular disorders. Condylar bone changes were classified into four types: no bone change (24 joints); flattening (19 joints); osteophyte formation (13 joints); and erosion (18 joints). RESULTS: The roof of the glenoid fossa was significantly thicker in joints with bone change than in joints with no bone change (Mann-Whitney U-test, P<0.05). There was also a significant difference in relation to the type of condylar bone change: the thickness of the roof of the glenoid fossa in the erosion group was significantly greater than in the no bone change (P<0.01), flattening (P<0.05) and osteophyte formation (P<0.05) groups (Kruskal-Wallis and Games-Howell tests). CONCLUSION: Compensative bone formation in the roof of the glenoid fossa might help to withstand the increased stress in the TMJ accompanying condylar bone change, especially erosion.

Great potentiality of neonatal facial motor neurons for neural plasticity as determined by functionally essential neuronal population.

The present study was undertaken to determine the neuronal population essential for normal and minimal facial function of young adult rats that had received various degrees of crush injuries to the facial nerve in the neonatal period. Using a neuronal tracer, it was found in young adult rats receiving neonatal injuries that the minimum number of tracer-labeled facial motor neurons necessary for normal facial function corresponded to 13-14% of the neurons (2540+/-64) of the age-matched control animals, whereas the minimum number of neurons necessary for minimal facial function corresponded to 5%. On the other hand, the minimum numbers of tracer-labeled facial motor neurons necessary for normal and minimal facial function of young adult rats that received various degrees of crush injuries corresponded to 61 and 27-30%, respectively, of the neurons (2540+/-64) of the uninjured control animals. These results indicate that the facial function of animals with nerves crushed at the neonatal stage can be adequately maintained by a very small population of neurons, implying a great potential of neonatal neurons for neural plasticity.

Regenerative process of the facial nerve: rate of regeneration of fibers and their bifurcations.

After the main trunk of the mouse facial nerve was injured by crushing, a fiber tracing method was used to quantify the facial motor neurons that extended regenerating nerve fibers to the specific site of the facial nerve branch. The total number of motor neurons retrogradely labeled with a fluorescent tracer, Fluoro-Gold (FG), were 0 on postsurgical days (PSDs) 1 and 2, 75+/-25 on PSD3, 264+/-21 on PSD4, 378+/-19 on PSD6, 428+/-19 on PSD8, 491+/-13 on PSD12 and 532+/-15 on PSD16. Assuming that the FG-positive neurons (535+/-11) of the control mice represent 100%, the FG-labeled neurons accounted for 0, 14, 49, 71, 80, 92 and 99% on the corresponding days. Two different fluorescent tracers were applied to the different facial nerve branches 16 days after facial nerve injuries. Double-labeled neurons were consistently found in the nerve-crushed facial nucleus (3.2%), and their number increased in the nerve-transected facial nucleus (12.2%). The present study indicates that the regenerating facial nerve consists of heterogeneous nerve fibers with varying growth rates and that excessive axonal branching occurs more frequently in the nerve-transected than in the nerve-crushed injuries.

Functionally essential neuronal population of the facial motor nucleus.

Cranial nerve impairment is one of the more serious complications in neurosurgery. Nevertheless, the important question of how many neurons are required for cranial nerve functions remains unanswered. The VIIth cranial nerve (facial nerve) in mice was subjected to graded crush injuries. After assessment of the facial function, the number of uninjured, healthy facial motor neurons was quantified with a retrograde neuronal tracer. We report that normal facial function is preserved if intact neurons account for more than 56% of the control value, while complete facial paralysis occurs if intact neurons are reduced to less than 32% of the control value.

Periosteal osteosarcoma of the mandible.

We report a rare case of periosteal osteosarcoma of the mandible in a 15-year-old girl. Extension of the tumour into the bone marrow by way of the periodontal ligament is demonstrated.

Correlation with redox potentials and inhibitory effects on Epstein-Barr virus activation of azaanthraquinones.

The redox potentials have been determined for nine azaanthraquinones in phosphate buffer at pH 7.2 by means of cyclic voltammetry. A definite correlation has been found between the redox potentials and the inhibitory effects of the azaanthraquinones on Epstein-Barr virus early antigen (EBV-EA) activation. It has further been shown that the correlation can be made better by introducing an electronic property, i.e., the atomic charge at O11 as an additional parameter.

[A giant thrombosed aneurysm of the anterior communicating artery which developed 18 years after clipping: a case report].

A 64-year-old man, who had undergone clipping surgery 18 years before for a ruptured anterior communicating artery (ACoA) aneurysm, presented with mild aphasia. A computerized tomography (CT) scan showed a subcortical hemorrhage in the left temporal lobe, and a high density large mass at the ACoA. Neuro-imaging study revealed a giant thrombosed ACoA aneurysm. Thrombectomy and neck clipping were successfully performed, using the interhemispheric approach. The patient was discharged without additional neurological deficits. A long-term follow-up study is thus considered necessary after neck clipping of a ruptured aneurysm.

Cerebral vasoreactivity and internal carotid artery flow help to identify patients at risk for hyperperfusion after carotid endarterectomy.

BACKGROUND AND PURPOSE: Hyperperfusion syndrome is a rare but potentially devastating complication after carotid endarterectomy (CEA). The aim of this study was to investigate whether preoperative measurement of cerebral vasoreactivity (CVR) and intraoperative measurement of internal carotid artery (ICA) flow could identify patients at risk for hyperperfusion after CEA. METHODS: For 26 patients with unilateral ICA stenosis >/=70%, cerebral blood flow (CBF) and CVR were investigated before and 1 month after CEA, with resting and acetazolamide-challenge single-photon emission CT. CBF on the first postoperative day was also measured. ICA flow was measured before and after reconstruction by electromagnetic flowmeter during surgery. RESULTS: Ipsilateral CBF on the first postoperative day significantly increased relatively (56.6+/-53.2%) as well as absolutely (37.9+/-8.8 to 57.7+/-18.0 mL/100 g per minute) in the reduced CVR group (CVR <12%) but not in the normal CVR group (CVR >/=12%) (10.3+/-15.5% and 40.6+/-7.9 to 43.9+/-5.7 mL/100 g per minute, respectively). One month later, this difference almost disappeared. Two patients showed ipsilateral CBF increase of >/=100%. A significant association of intracerebral steal with hyperperfusion (CBF increase >/=100%) on the first postoperative day was also observed. ICA flow increase after reconstruction significantly correlated with CBF increase on the first postoperative day in the reduced CVR group but not in the normal CVR group. The threshold of ICA flow increase for hyperperfusion was estimated to be 330 mL/min in the reduced CVR group. CONCLUSIONS: Single-photon emission CT with acetazolamide challenge and ICA flow measurement during surgery could identify patients at risk for hyperperfusion after CEA, in whom careful monitoring and control of blood pressure should be initiated even intraoperatively.