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At least 595 records · Page 33Linked to original sources
PubMedDate not supplied

Reconstruction of scalp defects using simple designed bilobed flap.

We have devised a novel rational method to design a bilobed flap. In our method, two triangle flaps are designed; the angle of the first flap is three-fourths the angle of a rhombus at the defect site, and the angle of the second flap is also three-fourths that of the first flap. We have successfully performed reconstruction of scalp defects as large as 50 x 45 mm using simple designed bilobed flaps. The location of the defect was the parietal region in 10 cases, the frontal region in 6 cases, the temporal region in 3 cases, and the occipital region in one case. The advantages of this method for use in reconstruction of scalp defects are as follows: (1) the dispersion tension on the flap provides stable circulation and prevents expansion of scar formation; (2) since the suture line is zigzag, alopecia at the suture line can be hidden under the hair; (3) since this flap is a random pattern flap using galea aponeurotica with blood flow to the skin, flap design is possible for any part of the scalp; and (4) design and elevation of this flap are easy and do not take much time.

Adolescent↗
PubMed2006

Spherical splines and average referencing in scalp electroencephalography.

EEG analysis and interpretation are affected by the reference electrode. Average referenced potentials are used widely to approximate the potentials relative to infinity, but estimates of the average surface potential are prone to errors due to incomplete sampling of the scalp surface. Even if the electrode density is high, this arises by not sampling the inferior scalp surface. This paper shows analytically how the spherical splines represent the average surface potential. It also shows that, for spline orders m > or = 3, the interpolating function is well approximated by its large-m limit, weighting near and distant electrodes with opposite signs. Together these motivate the hypothesis that spherical splines permit a better estimate of the potentials relative to infinity than the discrete average computed over superior scalp electrodes. It tests this hypothesis using numerical simulations in a four-sphere head model with single- and many-dipole sources, and variations in spline order, electrode number and head model parameters. The results confirm that the spherical splines yield a better estimate of the potentials relative to infinity, provided the electrode sampling density is adequate.

Brain Mapping↗
PubMed1976

Bilateral scalp necrosis in temporal arteritis. A rare complication of Horton's disease.

In an elderly man bilateral temporal scalp necrosis complicating temporal (systemic giant cell) arteritis developed. The patient also demonstrated other features characteristic of this entity: (1) exquisite scalp tenderness and headache, (2) onset late in life, (3) visual disturbances, (4) general debility, (5) diagnostic temporal artery biopsy, and (6) gradual healing with glucocorticosteroid therapy. A computer assisted review revealed 13 similar cases of scalp necrosis associated with temporal arteritis published in the English literature.

Aged↗
PubMed1976

Fetal scalp abscess secondary to intrauterine monitoring.

Thirty-one cases of fetal scalp abscess secondary to internal fetal monitoring over a 32 month period were reviewed. The over-all incidence was 1:230 monitored labors, or 0.4 per cent. Twenty-nine infants were cultured, with no growth in 10, Staphylococcus epidermidis in 11, and pathogenic organisms in the remainder. Gram stains of the exudates generally supported the culture results. All cases responded to drainage, local care, and systemic antibiotics, with no deaths. One case of osteomyelitis of the skull was confirmed roentgenographically. A strong correlation between prolonged rupture of the membranes and scalp abscess was observed, but no definite infectious origin was confirmed. The etiology of scalp abscess secondary to monitoring remains obscure.

Abscess↗
PubMed1991

The prognostic implications of location for scalp melanoma.

The clinical and pathologic records of 95 patients with primary cutaneous melanoma isolated to the scalp and regional lymph nodes treated at the MD Anderson Cancer Center between 1976 and 1985 were reviewed to assess the effect of lesion location on the prognosis of scalp melanoma. The scalp was defined as an area bounded by the supraorbital ridges, superior nuchal line, zygoma, and mastoid, thereby including a large non-hair-bearing area. Patients were grouped according to lesion location: hair-bearing or non-hair-bearing; anterior or posterior to the mid-tragal line; and parietal versus frontal, temporal, or occipital. There was a similar distribution of prognostic factors between the anatomic subsites. Analysis by univariate and multivariate methods demonstrated that, in a hair-bearing area, in an area posterior to the mid-tragal line, or in the parietal region, lesion location was highly predictive of the patient's survival. For example, the 5-year, melanoma-specific survival rate was 65% overall, 86% for patients with lesions located in non-hair-bearing regions and 47% for those with lesions in hair-bearing regions (p = 0.0019).

Female↗
PubMed1985

A modified halo frame to assist omentum transfer to the scalp.

A modification of the halo frame to facilitate management of major scalp wounds is described. It has been used successfully in the management of a major scalp defect covered by a microvascular omental free flap. It has potential application in managing a replanted scalp.

Basal Cell Carcinoma↗
PubMed1986

Scalp expansion flaps.

A mean 5 year review of 20 patients who had surgery for localised alopecia of the scalp is presented. The technique of using scalp expansion flaps is described and evaluated: it is associated with a low morbidity and high patient satisfaction rate; it provides an excellent one-stage procedure for intermediate size defects and, in the frontal area, for larger defects. Particular emphasis is laid on making incision lines at right angles to the direction of hair growth in order to cover stretched scars, and in performing Z-plasties when closing small scalp defects. Finally, a rationale for the treatment of localised areas of baldness according to their size is put forward.

Adolescent↗
PubMed1992

Scalp replantation by arterialised venous network flow-through.

A successful clinical case of scalp replantation is presented where a suitable artery could not be identified in the amputated part. Reperfusion of the flap was achieved by an arteriovenous inflow anastomosis and a conventional venous anastomosis for drainage. The aesthetic and physiological success of this case suggests that arteriovenous scalp replantation is a potential avenue for treatment where arterio-arterial repair is not possible. The possible explanation for the success in this patient is the paucity of valves that exist in the venous network of the scalp and forehead, noted in our previous anatomical studies. Knowledge of the replanted tissue venous architecture provides an anatomical basis to understand the potential limitations of arteriovenous replantation.

Adult↗
PubMed1991

Artifactually high coherences result from using spherical spline computation of scalp current density.

Coherence computed from common reference montages inextricably confounds true coherence with power and phase at the recording and reference electrodes. Direct measurement of coherence requires reference-free EEG data, such as data from EEG scalp current densities (SCDs), which estimate the potential gradient perpendicular to the scalp. Perrin et al. (1989) presented a method for computing SCDs by taking the Laplacian of the scalp potential surface generated by spherical spline interpolation. When this method of computing SCDs was applied to EEG data gathered from young adults, very high values were observed for inter-electrode coherences computed from the spherical spline derived SCD data but not from coherences computed from the common reference data. These high coherences prompted further examination of the properties of the spherical spline function and of spherical spline derived SCDs. Simulated data were constructed, and coherence was computed on the simulated data and on the SCDs derived from the spherical spline procedure and from the Hjorth (1980) procedure. The results of those simulations are presented, which demonstrate that a major artifact is introduced by using the spherical spline procedure. This artifact results from the spline weighting matrix used to derive the SCDs and strongly inflates the inter-electrode coherences of the SCD transformed data.

Artifacts↗
PubMed1992

Morphological characteristics of the scalp far-field potentials evoked by median nerve stimulation in infants and children.

We investigated the somatosensory evoked potentials (SEPs) produced by median nerve stimulation in normal infants, children and adults, focussing upon the wave forms of the scalp far-field potentials (FFPs). In adolescents and adults, 3 or 4 positive FFPs preceded the widespread N18 component on the scalp, corresponding to P9, P11, P13 and P14 (or P13-14). In infants and children, however, the scalp FFPs often included 5 positive waves, the initial three of which were characteristically sharp and brief. This distinctive wave form, with 5 positive FFPs, was correlated with an Erb's potential having a bipeaked negative phase. We studied the temporal relationship of the 5 positive FFPs to the Erb's potential and the cervical SEPs and concluded that the initial 3 brief positive waves were produced by overlapping of a bipeaked "P9" and bipeaked "P11." Both "P9" and "P11" are stationary waves that are thought to originate in the first-order afferents, so they probably reflect the bipeaked appearance of the compound nerve action potential.

Action Potentials↗
PubMed1996

The start-stop-start phenomenon in scalp-sphenoidal ictal recordings.

The start-stop-start (SSS) phenomenon is an apparent abortive ictal onset separated from the main seizure discharge. It was previously described in seizures recorded with subdural electrodes. We have observed this phenomenon in scalp-sphenoidal ictal recordings as well. We retrospectively reviewed 435 seizures recorded with scalp-sphenoidal electrodes from 61 patients with temporal lobe epilepsy. We found SSS onset in 15 seizures of 8 patients, representing 26% of these patients' seizures. The first "start" usually had a narrow field, typically in the sphenoidal electrode. The mean duration of the first "start" was 11 sec and that of the stop 8 sec. The restart had a different morphology and frequency in 87% and had a wider field in 67% of seizures. The clinical onset followed the first start and preceded the restart in most of the seizures. In 1 patient, 1 seizure with SSS was correctly localized and lateralized, whereas 5 of 7 without SSS were falsely lateralized. The recognition of the SSS phenomenon may improve the accuracy of seizure localization in scalp-sphenoidal recordings.

Electrodes↗
PubMed1994

Scalping injuries: dos and don'ts.

Replantation is the treatment of choice in scalping injuries and should always be considered, even in case of a badly damaged scalp. Specific procedures regarding pre-, intra- and postoperative care are crucial to success in replantation. These include: haemodynamic stabilization of the patient without causing damage to possible donor vessels; cooling, cleaning and further proper care of the avulsed specimen; use of antibiotics and haemodilution to optimize the intra- and post-operative situation. The above is illustrated by a case history of successful replantation of a seriously damaged avulsed scalp.

Adult↗
PubMed1995

Conductivity ratios of the scalp-skull-brain head model in estimating equivalent dipole sources in human brain.

The dipole tracing (DT) method estimates the position and vector dipole moment of an equivalent current dipole by minimizing the mean squared error of the dipole potentials at the surface electrode positions. In the scalp-skull-brain/DT (SSB/DT) method, which we have developed, the head model consists of three compartments of uniform conductors corresponding to the scalp, skull and brain. The accuracy of the calculations are mainly dependent on the ratios of the conductivities of the three compartments. The best result was obtained with the conductivity ratios of 1:1/80:1 for the scalp, skull and brain compartments, respectively.

Brain↗
PubMedDate not supplied

Wave form decomposition of 'giant SEP' and its computer model for scalp topography.

By using the decomposition technique developed by ourselves to investigate the scalp topography of evoked potentials, a computer model for the scalp topography of giant SEPs was computed from 5 patients with progressive myoclonic epilepsy and was compared with those obtained from 6 normal subjects. Components of giant SEPs were similar to those of normal SEPs with respect to various parameters, although the former were much larger than the latter. An experimental enlargement of some of the early cortical components of the normal SEP model gave rise to a wave form closely resembling that of the giant SEP. These findings support our previous conclusion, derived from study of the scalp topography of the original SEP wave form, that the giant SEP results from a pathological enhancement of certain early cortical components of the normal SEP. The underlying neuronal hyperexcitability seems to involve more than one subunit of the sensorimotor cortex.

Adolescent↗
PubMedDate not supplied

Evaluation of reference sites for scalp potentials evoked by painful and non-painful sural nerve stimulation.

The objective of this study was to evaluate reference sites for recording the middle- and long-latency scalp potentials elicited by painful and non-painful sural nerve stimulation. Somatosensory evoked potentials (SEPs) were recorded from the scalp, the mastoid, the earlobe, the neck, and the wrist. Each site was referenced to the sterno-vertebral (SV) electrode, which is a balanced non-cephalic reference with essentially no ECG contamination. There was little or no activity recorded between the wrist and SV, and the SV was located within a region extending from the rostral neck to the wrist where the potentials were stable over space. Hence, the SV reference is indifferent for the middle- and long-latency potentials evoked by painful and non-painful sural nerve stimulation. There was, however, significant activity recorded from the earlobe and mastoid, sites which are frequently used as references for the SEP. It is important that investigators using these cephalic references to study the middle- and long-latency peaks of the SEP be aware of this activity as it will distort SEPs recorded from single sites and the SEP scalp topography, distortions which could unnecessarily complicate their interpretation.

Adolescent↗
PubMedDate not supplied

Somatotopy of human hand somatosensory cortex as studied in scalp EEG.

We recorded somatosensory evoked potentials (SEPs) in scalp EEGs during stimulation of the median nerve, the ulnar nerve and the individual digits in 3 normal subjects and in 1 epilepsy patient. In this patient we also measured SEPs from chronically indwelling subdural grid electrodes during electrocorticography (ECoG). We applied dipole modelling technique to study the 3-dimensional intracerebral locations and time activities of the neuronal sources underlying stimulation of different peripheral receptive fields. The sources underlying median nerve SEPs were located an average of 10.8 mm lateral inferior to those underlying ulnar nerve SEPs. Digit SEP sources showed a somatotopic arrangement from lateral inferior to medial superior in the order thumb, index finger, middle finger, ring finger and little finger, with some overlap or reversal for adjacent digits. The average distance between thumb and little finger was 12.5 mm. Thumb, index finger and middle finger were clustered around median nerve cortical representation, whereas ring finger and little finger were arranged around ulnar nerve cortex. In the epilepsy patient, the source localizations obtained in scalp EEGs showed good agreement with those on ECoGs. We conclude that SEPs recorded in scalp EEGs can be used to study functional topography of human somatosensory cortex non-invasively.

Adult↗
PubMed1993

Diagnostic and predictive value of horizontal sections of scalp biopsy specimens in male pattern androgenetic alopecia.

BACKGROUND: Vertical sections of small scalp biopsy specimens are often inadequate for the diagnosis of male pattern androgenetic alopecia (MPAA). Quantitative analysis of follicular structures in horizontal sections can provide more information. OBJECTIVES: Our purpose was to establish better diagnostic criteria by comparing horizontal and vertical sections of scalp biopsy specimens from MPAA and normal control subjects and to determine the predictive value of horizontal sections, by relating counts of follicular structures in MPAA to subsequent hair regrowth from topical minoxidil therapy. METHODS: Paired 4 mm punch biopsy specimens were taken from 22 normal control subjects and 106 patients with MPAA, for horizontal and vertical sectioning. In horizontal sections, hair bulbs, terminal anagen, catagen and telogen hairs, telogen germinal units, and vellus hairs were counted, as were follicular units and stelae. RESULTS: The diagnosis of MPAA was confirmed by finding decreased terminal hairs and increased stelae and vellus hairs. The average horizontal section contained 22 terminal and 13 vellus hairs, a 1.7:1 ratio. Changes compatible with MPAA were found in most vertical and horizontal sections, but horizontal sections were required for follicular counts and showed terminal:vellus hair ratios diagnostic of MPAA in 67% of cases. Of 44 patients treated with topical minoxidil, five with less than 2 follicular structures/mm2 showed no hair regrowth, 32 with 2 to 4 follicular structures/mm2 showed regrowth in 72%, and seven with more than 4 follicular structures/mm2 showed regrowth in 86% of cases. In MPAA with no significant inflammation, regrowth occurred in 77% of cases, versus 55% in cases with significant inflammation. CONCLUSION: Horizontal sections of scalp biopsy specimens in MPAA provide more diagnostic information than vertical sections and appear to have a predictive value for hair regrowth.

Administration, Cutaneous↗
PubMed1988

Tangential excision of scalp burns: experience from the Bradford fire disaster.

Tangential excision of deep dermal scalp burns does not appear to be widely practised. During the Bradford Football fire victims sustained mixed depth scalp burns. These were mainly as a result of radiant heat, although falling molten bitumen was the cause of injury in a few patients. Deep dermal or full thickness burns of the scalp were tangentially excised and skin grafted. One patient did not have a graft applied after tangential excision. The early results of graft take were satisfactory. Subsequently, however, 56 per cent required further grafting; the reasons for this are discussed. Ten months after the incident there is no difference in appearance between areas of primary grafting and areas of secondary healing.

Adult↗