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Objective: Skull base chordomas are rare, locally osseo-destructive lesions that present unique surgical challenges due to their involvement of critical neurovascular and bony structures at the craniovertebral junction (CVJ). Radical cytoreductive surgery improves survival but also carries significant morbidity, including the potential for occipitocervical (OC) destabilization requiring instrumented fusion. The published experience on OC fusion after CVJ chordoma resection is limited, and the anatomical predictors of OC instability in this context remain unclear., Methods: PubMed and Embase were systematically searched according to the PRISMA guidelines for studies describing skull base chordoma resection and OC fusion. The search strategy was predefined in the authors' PROSPERO protocol (CRD42024496158)., Results: The systematic review identified 11 surgical case series describing 209 skull base chordoma patients and 116 (55.5%) who underwent OC instrumented fusion. Most patients underwent lateral approaches (n = 82) for chordoma resection, followed by midline (n = 48) and combined (n = 6) approaches. OC fusion was most often performed as a second-stage procedure (n = 53), followed by single-stage resection and fusion (n = 38). The degree of occipital condyle resection associated with OC fusion was described in 9 studies: total unilateral condylectomy reliably predicted OC fusion regardless of surgical approach. After lateral transcranial approaches, 4 studies cited at least 50%-70% unilateral condylectomy as necessitating OC fusion. After midline approaches-most frequently the endoscopic endonasal approach (EEA)-at least 75% unilateral condylectomy (or 50% bilateral condylectomy) led to OC fusion. Additionally, resection of the medial atlantoaxial joint elements (the C1 anterior arch and tip of the dens), usually via EEA, reliably necessitated OC fusion. Two illustrative cases are subsequently presented, further exemplifying how the extent of CVJ bony elements removed via EEA to achieve complete chordoma resection predicts the need for OC fusion., Conclusions: Unilateral total condylectomy, 50% bilateral condylectomy, and resection of the medial atlantoaxial joint elements were the most frequently described independent predictors of OC fusion in skull base chordoma resection. Additionally, consistent with the occipital condyle harboring a significantly thicker joint capsule at its posterolateral aspect, an anterior midline approach seems to tolerate a greater degree of condylar resection (75%) than a lateral transcranial approach (50%-70%) prior to generating OC instability.

Patients with metastatic colorectal cancer have a 5-year overall survival of less than 10%. Approximately 45% of patients with metastatic colorectal cancer harbor KRAS mutations. These mutations not only carry a predictive role for the absence of response to anti-EGFR therapy, but also have a negative prognostic impact on the overall survival. There is a growing unmet need for a personalized therapy approach for patients with KRAS -mutant colorectal cancer. In this article, we focus on the therapeutic strategies targeting KRAS - mutant CRC, while reviewing and elaborating on the discovery and physiology of KRAS.

Factor XIII (FXIII) deficiency is a rare autosomal recessive congenital disorder of haemostasis, associated with a high risk of intracranial haemorrhage. Intracranial haemorrhage can result in neurological sequelae including seizure disorders. In some cases, medically intractable epilepsy led to epilepsy surgery. Little has been reported on the management of FXIII deficiency during surgery, and there is only a few data on the management, safety and efficacy of epilepsy surgery in the patients with haemostatic disorder. We report here an epilepsy neurosurgery in a case of severe FXIII deficiency.

We analyse clinical characteristics, presurgical investigations, surgical procedures and outcome of 137 patients operated-on for a drug-resistant partial epilepsy, in Grenoble from January 1990 to December 1993. Moreover we present data of 63 patients suffering from a "pure" temporal lobe epilepsy selected using the following criteria: 1. surgery limited to temporal lobe structures 2. totally cured after surgery (Engel's class la).

Industrial intoxication by trichloroethylene can produce neurological disturbance of the trigeminal nerve. Therefore, among 105 workers exposed to this toxin, we recorded cortical responses after stimulation of the trigeminal nerve (TSEP) and we compared our results with a control group of 52 subjects. We considered the physical examination exploring, the facial sensitivity and reflexes, the levels of urinary metabolites of trichloroethylene and TSEP. We can describe 4 groups of workers: group A, 13 subjects with perturbations of clinical and evoked responses; group B, 27 subjects with normal physical examination though with disturbed TSEP; group C, 6 subjects had an abnormal examination though evoked responses were normal; group D, 59 subjects had normal clinical examination and TSEP. Disturbed TSEP (particularly delayed responses) are found among the older workers with the longest duration of exposure and higher level of exposure. The alteration of TSEP may appear before clinical disturbance. TSEP could represent a useful test for the supervision of the exposed workers and the clinical diagnosis of the trigeminal impairment.

Results of a study of trigeminal nerve impairment resulting from trichloroethylene intoxication by the somatosensory-evoked potential method reveal three kinds of abnormalities: increased stimulation voltage, excessive latency delay with morphological abnormalities, and excessive graph amplitude. These abnormalities confirm clinical disturbance (hypesthesia of the trigeminal nerve area) and open debate about the real mechanism of trichloroethylene neurotoxicity. Industrial intoxication by solvents, particularly trichloroethylene, is common. We have conducted a study of 188 workers chronically exposed to trichloroethylene and have confirmed the selective neurological disturbances of this intoxication in the trigeminal nerve (20%) [3, 10]. We utilized a new experimental method, developed for studies of chronic intoxications effecting the median nerve [5, 8], of recording the somatosensory evoked potential following stimulation of the trigeminal nerve [4, 6, 7]. The workers in this study were selected following clinical evaluation of their facial sensitivity and trigeminal nerve reflexes. In this paper we present our preliminary results on 11 workers, 9 suffering effects of intoxication and 2 controls.

In 65 patients with status epilepticus, we compared the clinical expression of isolated seizures and of status seizures. In 22 patients there was no relationship between status and isolated seizures. In addition the number of partial status is greater than that of partial seizures. In 9 patients, the type of seizures was modified after the status. From these results, status epilepticus seems to favor the eruption of secondary epileptogenic focuses, generally transitory.

The authors describe the EEG recordings of 107 patients with acute severe cranial trauma and signs of axial lesions. The initial EEG included: sleep patterns, alternating tracings, alpha band tracings which were either nonreactive pseudo-alpha or modulated alpha often reactive, and diffuse slow wave tracings. They found no particular tracing corresponding to a precise level of rostrocaudal destructuration, but some associations were seen more frequently. EEG sleep patterns and alternating tracings were never observed in brain stem lesions, the activity recorded being of low voltage, rigid, and non-reactive. The presence of spontaneous fluctuations (with sleep rhythms in some cases) and reactivity in other levels (mesodiencephalic junction, diencephalic and cortical-subcortical) are good prognostic signs. Focalised EEG signs are seen especially in the more rostral levels.

The authors present a comparative analysis of the characteristics of the V wave of the brain stem auditory evoked potentials in relation to the degree of transverse shifting of the third ventricle. The investigations were carried out in 48 patients with non-traumatic intracerebral haematoma. A high correlation was found between the size of the amplitude and ventricle shift. No such correlation was observed with the interpeak time of the I--V waves.

24 deep toxic comas with respiratory assistance were studied by brain-stem reflex and BAEP. Laboratory analysis showed several simultaneous toxics (phenobarbital, benzodiazepines, tricyclic antidepressants...). Three groups of patients were defined: Twelve patients with normal BAEP and with relatively preserved brain-stem reflex (oculocephalic and oculovestibular are often disturbed but photomotor is present). Eleven patients with delayed BAEP and with more disturbed brain-stem reflex (photomotor is missing 3 times). In 2 cases (one of which is mentioned above in group B) brain-stem reflex and BAEP disappear and these patients die. Cerebral anoxia is associated here with toxics. Causes of delayed latencies (group B) are discussed (hypothermia, toxics). BAEP seems important in diagnosis and prognosis of toxic coma.

From the study of 65 severe traumatic comas, the authors describe the syndrome of mesodiencephalic dysfunction, because of its frequency and its particular clinical signs. This peculiar level of loss of consciousness is characterized by a coma without mimic and without awakening after painful stimulation, by a stereotyped motor pattern in extension, by a perseverance of the photomotor reflex, while fronto-orbicular and vertical oculo-vestibular reflexes are lacking. This level of deterioration appears to be a critical point in the natural history of comatose patients. If this level is not surpassed, the probability of early death due to evolutive neurological lesion is low (18%). One half of these patients have a good prognosis, more than 75% have an excellent recovery. This high probability of recovery is decreased by a half when the level of mesencephalic dysfunction is reached.

The authors report the case of an 8 year-old boy who, when he was 2 1/2 years old, suffered from spasmodic mouth twitches. At the age of four, various other symptoms appeared: psychomotor backwardness, frequent fails and a photomyoclonic response on electroencephalogram. At the age of 5 1/2, noticeable difficulties appeared in walking with a broad-based gait, hypotonia, and intentional trembling associated with hypokinesia and dysarthria. When he was six, the first convulsive seizure appeared, then myoclonies which became continuous. The child gradually became bedridden. The family history tends to show these disorders can be linked with a Huntington chorea affecting six generations. This case is very similar to that previously described by the authors, in an 8 year-old girl where an anatomic examination revealed the existence of lesions characteristic of Huntington's disease associated with lesions of the cerebellum. The authors, on the basis of the data provided by the literature, discuss the myoclonic and cerebellous aspect of this infantile form. Lacking anatomic evidence, they stress the interest of the biochemical disturbances affecting the cerebral monoamines noted in this observation.

Results of a study concerning the trigeminal nerve impairment as the one caused by trichlorethylene chronic intoxication by somatosensory evoked potential reveal three kinds of anomalies: increase of the stimulation voltage, excessive latency delay with morphological anomalies and excessive graph amplitude. These anomalies confirm clinical disturbance (hypoesthesia in the trigeminal area) and open a debate about the real mechanism of the trichlorethylene neurotoxicity.

The authors studied four children with Reye's syndrome aged 16 months, 6 years, 8 years and 11 years respectively with severe liver failure and progressive coma. The laboratory investigations in all of them showed a marked elevation of serum transaminases, hyperammoniaemia and a prolongation of the prothrombin time. The electroencephalograms showed a grossly abnormal picture with generalised continuous delta activity. Three children survived with return to normal of the liver function tests whilst the fourth child died. In the last two patients an electroencephalogram carried out every six hours has enabled certain prognostic features to be determined. Improvement in the E.E.G. correlates closely with clinical improvement and vice versa. The authors also advocate serial E.E.G. recordings in Reye's syndrome. The role of hyperammonaemia in the genesis of encephalopathy and the electroencephalographic changed is discussed. The role played by raised intracranial pressure is stressed and the importance of controlling it in order to prevent further damage and improve the prognosis of this serious illness.

Recordings were made from 20 newborns during seizures in their first days of life, using a polygraphic study enabling observation of electro-clinical seizures, electric seizures, and seizures with no EEG transfer. The interictal EEG as well as the duration of status epilepticus are discussed. An estimation of the prognosis from the EEG clinical criteria is envisaged. CT scans and ultrasound scans were performed in serious cases of neonatal distress responsible for status epilepticus; these showed diffused or localized oedema of the white matter, either isolated or associated with intracranial hemorrhagic lesions.

Trigeminal nerve impairment is frequently seen in chronic trichlorethylene intoxication (TRI). A total of 104 occupationally exposed subjects were selected for study because they were employed at a highly exposed workplace. They were studied by clinical examination and by trigeminal somatosensory evoked potentials (TSEP). Normal values for TSEP were obtained from the study of 52 healthy nonexposed subjects. Facial hypoesthesia, when present, was global and predominant in the mandibular and maxillary nerve areas, associated or not with absent reflexes. A disturbed TSEP was found in 40 subjects which was predictable from their clinical symptoms. Correlation with exposure parameters (duration of exposure, trichlorethanol, and trichloracetic acid urinary rates) was mainly observed in subjects presenting both clinical and electrical alterations. Electrical alterations alone were less predictive. An abnormal TSEP may thus provide objective determination of risk assessment in the absence of clinical signs.