[Laparoscopic cholecystectomy as standardised teaching operation to treat symptomatic cholecystolithiasis]. / Die laparoskopische Cholezystektomie als standardisierter Lehreingriff zur Behandlung der symptomatischen Cholezystolithiasis.

Currently laparoscopic cholecystectomy is the gold standard of therapy for diseases related with gallstones, namely symptomatic cholecystolithiasis, acute and chronic cholecystitis and also as therapy for gallbladder adenoids. Together with laparoscopic appendectomy, this procedure often is one of the first laparoscopic operations performed by new interns. Therefore a standardised, reproducible approach to ensure the patient safety is necessary. The procedure can be subdivided into 10 substeps--so-called "nodal points"--which must be completed before the next substep can be started. This article and the attached video show the ten "nodal points" of a standardised laparoscopic cholecystectomy.

Spatiotemporal maturation of the central and lateral N1 components to tones.

This paper examines maturational changes in the spatiotemporal features of central and lateral N1 components of the auditory evoked potentials (AEPs) to tone stimuli presented with a long stimulus onset asyncrony (SOA; 4200 ms) using the scalp current density (SCD) technique. A group of typically developing children ranging from 6 to 12 years of age and a group of adults were studied. Recently studies have begun to explore the topography of these components in children. These studies, however, often used rapidly presented stimuli and did not elicit observable central N1s in the younger children. Our stimuli elicited both central and lateral N1s. Peak latencies of both components decreased with age. Peak amplitude also decreased with age for the lateral N1 but not for the central N1. Consequently, the difference between the lateral N1 and the central N1 amplitudes (or the ratio of lateral N1 amplitude to central N1 amplitude) also decreased with age, dramatically altering the morphology of the elicited AEP waveforms. Topography of the lateral N1 did not change with age. The location of maximal activation for the central N1 appeared to move more medially with age but this 'apparent' movement is probably due to the decreasing impact of the partially overlapping lateral N1 component whose amplitude is significantly smaller in adults than in children.

Maturation of mismatch negativity in school-age children.

OBJECTIVE: Event-related potentials were recorded to investigate the maturation of auditory processing in school-age children. DESIGN: The mismatch negativity (MMN) was obtained in an oddball tone discrimination paradigm in 66 school-age children and 12 adults. In the children's data, a prominent negativity to both the standard and deviant tone, peaking around 200 msec, was observed, and compared with the N1 auditory evoked potential component. RESULTS: The MMN was found to decrease with latency by 11 msec/yr from 4 to 10 yr of age. No developmental change in MMN amplitude was seen from 4 to 10 yr of age. However, the MMN amplitude was significantly smaller in adults than in children. The prominent negativity in children was significantly later than the adult N1 component, and did not change in latency from 4 to 10 yr of age. This finding adds to a body of evidence suggesting that this prominent negativity and the adult N1 are not the same component. The magnitude of the prominent negativity in children decreased slightly with age. CONCLUSION: Changes in the timing of the brain discriminative response, MMN, suggest systematic maturational changes in auditory processing.

Electrophysiologic manifestations of impaired temporal lobe auditory processing in verbal auditory agnosia.

The present study examined the extent to which verbal auditory agnosia (VAA) is primarily a phonemic decoding disorder, as contrasted to a more global defect in acoustic processing. Subjects were six young adults who presented with VAA in childhood and who, at the time of testing, showed varying degrees of residual auditory discrimination impairment. They were compared to a group of young adults with normal language development matched for age and gender. Cortical event-related potentials (ERPs) were recorded to tones and to consonant-vowel stimuli presented in an "oddball" discrimination paradigm. In addition to cortical ERPs, auditory brainstem responses (ABRs) and middle latency responses (MLRs) were recorded. Cognitive and language assessments were obtained for the VAA subjects. ABRs and MLRs were normal. In comparison with the control group, the cortical ERPs of the VAA subjects showed a delay in the N1 component recorded over lateral temporal cortex both to tones and to speech sounds, despite an N1 of normal latency overlying the frontocentral region of the scalp. These electrophysiologic findings indicate a slowing of processing of both speech and nonspeech auditory stimuli and suggest that the locus of this abnormality is within the secondary auditory cortex in the lateral surface of the temporal lobes.

Developmental studies and clinical application of mismatch negativity: problems and prospects.

There is wide interest in the clinical application of mismatch negativity (MMN) to assess discriminative capabilities in individuals whose auditory capacities are difficult to determine, including infants, young children and those with severe cognitive impairment. Before MMN can be used as a clinical electrophysiologic measure, it is necessary to establish that it can be reliably elicited in normal individuals. This chapter describes a detailed analysis of MMN recorded in a group of healthy 8-yr-old children to assess intrasubject and intersubject reliability of the response. We conclude that although statistically reliable results can be obtained with group data, and perhaps even in individuals when large numbers of stimuli can be delivered, the unfavorable signal to noise ratio of individual MMN data currently limits its clinical applicability. Suggestions for approaches to surmount these difficulties are presented for its eventual clinical usefulness.

Flash and pattern-reversal visual evoked potential abnormalities in infants and children with cerebral blindness.

Visual evoked potentials (VEPs) were recorded of 60 infants and children with cerebral blindness, aged between six weeks and 10 years, and compared with age-matched normative data. Every patient had abnormal VEPs. 18 had absent flash and pattern VEPs and 13 had atypical or atypical and asymmetrical flash and pattern VEPs. Of the remaining 29, most had greater abnormality of pattern than of flash VEPs and greater abnormalities over parietal and temporal than occipital areas. Eight patients had normal occipital responses to flash and five others had delayed responses with normal morphology. One had normal occipital responses to pattern stimuli. All of these had abnormal late occipital responses or abnormal responses over the parietal and temporal areas. It is recommended that visual assessments using VEPs employ both flash and pattern stimuli, that pre-occipital as well as occipital recordings be made and that tracings be compared with age-specific normative data.

Cortical responses to speech sounds and their formants in normal infants: maturational sequence and spatiotemporal analysis.

Cortical auditory evoked potentials (AEPs) to the synthesized syllables [da[ and [ta[ and to the isolated 3 formants of [da[ were obtained from 32 normal infants studied at monthly intervals from birth through 3 months and at 6 months of age. A bilateral array of 16 electrodes referenced to the mid-occiput permitted a topographic analysis of the cortical AEPs at selected latencies. A differential maturational sequence was seen: a predominantly negative cortical AEP wave form became positive, first over the frontocentral region (around term), and then over the temporal region (at 1-2 months). The timing of these electrophysiological changes coincides with a differential anatomical maturational sequence in the auditory cortex, as myelination and synaptogenesis are more advanced in primary than secondary auditory areas at term. All infants in this study followed this developmental sequence. However, there was no systematic effect of the center frequency of the formant stimuli on the maturational level of their respective cortical AEPs, suggesting a relative maturational equivalence in those regions of auditory cortex responding to stimuli across the frequency range present in human speech. In term infants, an initial midline positivity and bitemporal negativities were asynchronous in their peak and offset latencies. suggesting independent generators for each of these components. In infants from 3 to 6 months of age, cortical AEP wave forms consisted of 2 initial positive peaks followed by a negative peak. While the wave forms were similar over midline and lateral scalp, spatiotemporal analysis revealed differences in the latency of onset, duration and in the spatial extent of these components, again suggesting that 2 bilateral, temporally overlapping generators contribute to the cortical AEP. No systematic topographic difference was observed in the cortical AEPs elicited by each of the 3 formants, which differed in center frequencies.

Differential maturation of cortical auditory evoked potentials to speech sounds in normal fullterm and very low-birthweight infants.

Cortical auditory evoked potentials (AEP) to the consonant-vowel syllables/da/and/ta/and 800Hz tone were recorded at 40 weeks post-conceptional age and at one, two and three months after term in normal fullterm and very low-birthweight infants. As a group, the very low-birthweight infants exhibited significantly less mature AEPs to consonant-vowel syllables than the normal-birthweight infants at 40 weeks post-conceptional age. Consistent but statistically non-significant differences also were found for tones at 40 weeks post-conceptional age, and for all stimuli at one and two months after term. By three months, all the infants exhibited mature AEP morphology and topography.