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PubMed1993

Turn-specific differences in the endocochlear potential between albino and pigmented guinea pigs.

Recent findings indicate that structural differences exist in the stria vascularis (SV) between albino and pigmented guinea pigs. In the higher cochlear turns, volume density for marginal cells in the albino SV is abnormally large, while that for intermediate cells (melanocytes) is abnormally small. These anatomical variations suggest that functional differences between albino and pigmented inner ears also may be found. To examine this possibility, four strains of guinea pigs were studied, consisting of Hartley albino (N = 9) and NIH outbred pigmented (N = 15) guinea pigs, as well as albino (N = 11) and pigmented (N = 15) guinea pig siblings born to mixed litters. Tracheotomy and carotid artery cannulation were performed. Animals were mechanically ventilated, with periodic samples drawn for arterial blood gas analysis. Blood pressure, heart rate and rectal temperature were monitored. Compound action potentials were measured first to assess cochlear viability. Positive endocochlear potentials (+EP) then were recorded, beginning with the fourth turn, followed by the first, second and third turns. Results showed that the +EP in albinos remained relatively constant across cochlear turns, but decreased significantly from base to apex in the pigmented inner ears. Across all animals, mean +EPs (mV +/- S.E.M.) for turns 1-4 in albinos were: 72.5 (2.5), 68.7 (2.3), 59.2 (2.7), 68.1 (3.3); pigmented values were: 72.9 (2.9), 66.9 (2.6), 53.8 (3.0), 57.0 (2.7). One-way ANOVAs did not show a significant difference in albino +EPs between any of the cochlear turns, but did indicate a highly significant difference between turns in the pigmented inner ears (P < 0.000004). Post hoc comparisons demonstrated +EPs in turns 3 and 4 were smaller than in turn 1. Since turn 3 was recorded last in these experiments, and was reduced in value relative to turn 4 in both groups, it is likely that cochlear deterioration contributed to this result more than any other factor. These results, combined with previous anatomical data, indicate that a diminution of melanocyte cell volume in the albino SV is accompanied by an increase in marginal cell volume density and larger +EPs in the higher cochlear turns, at least at resting levels.

Albinism↗

PubMed1998

Endoscope-assisted brain surgery: part 1--evolution, basic concept, and current technique.

RATIONALE: The evolution of neurosurgical techniques indicates the effort to reduce surgery-related traumatization of patients. The reduction of traumatization contributes to better postoperative outcomes. The improvement of diagnostic imaging techniques facilitates not only the precise localization of lesions but also the accurate determination of topographical relations of specific lesions to individual anatomic variations of intracranial structures. This precision of diagnostic imaging should be used to perform individual surgical procedures through so-called keyhole approaches. Keyhole craniotomies are afflicted with a reduction of light intensity in the depth of the operating field, and they provide rather narrow viewing angles. Thus, objects located directly opposite the approach entrance are more visible than those in the shadow of the microscope beam. These two deficiencies of keyhole craniotomies can be compensated for by the intraoperative use of rigid rod lens endoscopes, the shaft of which remains easily controllable through the surgical microscope. CONCEPT: Endoscope-assisted microsurgery, like all routine microsurgical procedures, is performed with both hands; the endoscope is fixed in its desired position via a mechanical arm to the headholder. Because of their superior optical quality and maneuverability, only rigid lens scopes are used for endoscope-assisted brain microsurgery. There are five ways of observing the endoscopic and microscopic images at the same time: 1) observation of the microscopic image through the oculars of the microscope and observation of the endoscopic image on a video screen placed in front of the surgeon, 2) observation of the microscopic image through the oculars of the microscope and display of the endoscopic image on a head-mounted LCD screen, 3) projection of both microscopic and endoscopic images on one screen in a picture-in-picture mode, 4) projection of both microscopic and endoscopic images into specially designed microscope oculars, and 5) transmission of both microscopic and endoscopic images into a head-mounted LCD screen. DISCUSSION: With the knowledge of almost all individual anatomic and pathoanatomic details of a specific patient, it is possible to target the individual lesion through a keyhole approach using the particular anatomic windows. As the light intensity and the depiction of important anatomic details are improved by the intraoperative use of lens scopes, endoscope-assisted microsurgery during keyhole approaches may provide maximum efficiency to remove the lesion, maximum safety for the patient, and minimum invasiveness.

Brain↗

PubMed2003

Piriformis syndrome: anatomic considerations, a new injection technique, and a review of the literature.

BACKGROUND: Piriformis syndrome can be caused by anatomic abnormalities. The treatments of piriformis syndrome include the injection of steroid into the piriformis muscle and near the area of the sciatic nerve. These techniques use either fluoroscopy and muscle electromyography to identify the piriformis muscle or a nerve stimulator to stimulate the sciatic nerve. METHODS: The authors performed a cadaver study and noted anatomic variations of the piriformis muscle and sciatic nerve. To standardize their technique of injection, they also noted the distance from the lower border of the sacroiliac joint (SIJ) to the sciatic nerve. They retrospectively reviewed the charts of 19 patients who had received piriformis muscle injections, noting the site of needle insertion in terms of the distance from the lower border of the SIJ and the depth of needle insertion at which the motor response of the foot was elicited. The authors tabulated the response of the patients to the injection, any associated diagnoses, and previous treatments that these patients had before the injection. Finally, they reviewed the literature on piriformis syndrome, a rare cause of buttock pain and sciatica. RESULTS: In the cadavers, the distance from the lower border of the SIJ to the sciatic nerve was 2.9 +/- 0.6 (1.8-3.7) cm laterally and 0.7 +/- 0.7 (0.0-2.5) cm caudally. In 65 specimens, the sciatic nerve passed anterior and inferior to the piriformis. In one specimen, the muscle was bipartite and the two components of the sciatic nerve were separate, with the tibial nerve passing below the piriformis and the peroneal nerve passing between the two components of the muscle. In the patients who received the injections, the site of needle insertion was 1.5 +/- 0.8 (0.4-3.0) cm lateral and 1.2 +/- 0.6 (0.5-2.0) cm caudal to the lower border of the SIJ as seen on fluoroscopy. The needle was inserted at a depth of 9.2 +/- 1.5 (7.5-13.0) cm to stimulate the sciatic nerve. Patients had comorbid etiologies including herniated disc, failed back surgery syndrome, spinal stenosis, facet syndrome, SIJ dysfunction, and complex regional pain syndrome. Sixteen of the 19 patients responded to the injection, their improvements ranged from a few hours to 3 months. CONCLUSIONS: Anatomic abnormalities causing piriformis syndrome are rare. The technique used in the current study was successful in injecting the medications near the area of the sciatic nerve and into the piriformis muscle.

Adult↗

PubMed2004

Validation of anatomical standardization of FDG PET images of normal brain: comparison of SPM and NEUROSTAT.

PURPOSE: Statistical parametric mapping (SPM) and NEUROSTAT (NS) are widely used for intersubject statistical analysis of brain images. We investigated individual anatomical variations after standardization of 18F-fluorodeoxyglucose positron emission tomography (FDG PET) images of normal brain and compared the differences in the standardized images obtained from SPM and NS. METHODS: Twenty healthy normal subjects were recruited for FDG PET and magnetic resonance imaging (MRI) studies. Sylvian fissures (SF), cingulate sulci (CingS) and central sulci (CtlS) were marked on the brain surface of each individual's co-registered MR images. Then spatial standardization was performed on each subject's PET images using SPM99 and NS with NS's FDG template image, and each subject's MR images (with the SF, CingS, and CtlS marked in advance) were standardized using the sets of parameters obtained from PET standardization by SPM and NS, respectively. The coordinates of each subject's SF, CingS, and CtlS detected on the MR images standardized by the two methods were measured and compared with those on the template images. RESULTS: The mean individual deviations from the averaged coordinates for the markers on the SF, CingS and CtlS standardized by SPM and by NS were no more than 0.21-1.15 mm. The number of voxels within the brain volume on standardized MR images of all 20 subjects was 88.0% of the total number of brain volume voxels for SPM and 85.3% for NS. CONCLUSION: This study demonstrates that SPM and NS yield relatively small differences in standardization and that both methods are effective and valid for PET studies in normal subjects.

Adolescent↗

PubMedDate not supplied

Endoscopically facilitated reduction laryngochondroplasty.

Endoscopic verification of the level of excision of the thyroid cartilage in reduction laryngochondroplasty maximizes the aesthetic result of the operation and prevents possible injury to the vocal cords. A prominent thyroid cartilage is identified with male sex. Reduction of the thyroid cartilage prominence (Adam's apple), also known as laryngochondroplasty, is often requested by patients undergoing male-to-female transsexual surgery. Some women, and even occasional slender men, with a markedly pronounced thyroid cartilage prominence also request this treatment to refine their neck contour. Topographic studies place the true vocal cords at a level corresponding to halfway up the thyroid cartilage. Because of the proximity of the thyroid cartilage prominence to the attachment of the true vocal cords, any anatomic variation may lead to injury to the phonatory apparatus during the cartilage excision. Attempts to avoid this occurrence may result in overconservative reduction of the thyroid prominence and less-than-optimal aesthetic results. Herein we describe a combined endoscopic and external surgical approach to reduction laryngochondroplasty.

Endoscopy↗

PubMed1995

Optical coherence tomography of the human retina.

OBJECTIVE: To demonstrate optical coherence tomography for high-resolution, noninvasive imaging of the human retina. Optical coherence tomography is a new imaging technique analogous to ultrasound B scan that can provide cross-sectional images of the retina with micrometer-scale resolution. DESIGN: Survey optical coherence tomographic examination of the retina, including the macula and optic nerve head in normal human subjects. SETTING: Research laboratory. PARTICIPANTS: Convenience sample of normal human subjects. MAIN OUTCOME MEASURES: Correlation of optical coherence retinal tomographs with known normal retinal anatomy. RESULTS: Optical coherence tomographs can discriminate the cross-sectional morphologic features of the fovea and optic disc, the layered structure of the retina, and normal anatomic variations in retinal and retinal nerve fiber layer thicknesses with 10-microns depth resolution. CONCLUSION: Optical coherence tomography is a potentially useful technique for high depth resolution, cross-sectional examination of the fundus.

Fovea Centralis↗

PubMed2005

Multiplanar computed tomographic analysis of frontal recess cells: effect on frontal isthmus size and frontal sinusitis.

BACKGROUND: Frontal recess anatomy can be very complex, with accessory cells such as frontal, agger nasi, and intersinus septal cells encroaching on the frontal recess and possibly contributing to obstruction of the frontal sinus. In this study, we determined the prevalence of these cells and their relationship to frontal sinusitis in patients who have (revision group) and have not (primary group) had previous sinus surgery. DESIGN: Multiplanar computed tomographic images were reconstructed on a computer workstation to determine the presence of frontal, agger nasi, and intersinus septal cells and frontal sinusitis. We also measured the diameter and area of the frontal isthmus for each sinonasal cavity. We were able to retrieve 106 of 117 images from a surgical database encompassing the previous 2 years. SETTING: Tertiary care academic practice of the senior author. RESULTS: Frontal cells were found in 25.5% of frontal recesses, including 29.6% of sides in the primary group and 21.9% of sides in the revision group. We identified 33.0% of patients as having unilateral or bilateral frontal cells. Type I cells were the most common cell (18.4% of primary sinuses). The presence of frontal sinusitis and the diameter and area of the frontal isthmus were not significantly different for those patients with compared with patients without frontal cells. Intact agger nasi cells were identified in 86.7% of primary sinuses and 53.5% of revision sinuses. There was no increased incidence of frontal sinusitis in patients with persistent agger nasi cells in the revision group. CONCLUSIONS: When we evaluated multiplanar reconstructions, we identified frontal cells in 33.0% of patients overall, which was more common than previously reported. The findings of agger nasi cells indicated that these cells were likely addressed in less than half of previous sinus procedures. However, frontal cells and retained agger nasi cells were not associated with a higher incidence of frontal sinusitis, and there was no association between the size of the frontal isthmus and the presence of frontal sinusitis. Although anatomic variations in the frontal recess are likely to play a role in frontal sinusitis, mucosal inflammatory processes are likely to be a much more important etiologic factor.

Cohort Studies↗

PubMed1981

Superior laryngeal nerve paralysis and benign thyroid disease.

A case of an isolated superior laryngeal nerve paralysis from a thyroid adenoma is presented. Superior laryngeal nerve paralyses should be sought, particularly in the preoperative and postoperative examination of thyroidectomy patients. Symptoms of a change in vocal strength or pitch and aspiration along with the laryngoscopic findings of a glottis posteriorly rotated toward a bowed vocal cord are diagnostic. Surgical trauma to the superior laryngeal nerve, though a risk of any thyroidectomy, usually can be avoided if one knows its possible anatomic variations and meticulously dissects the superior thyroid pole and its vessels.

Adenoma↗

PubMed1988

Conchomeatoplasty for chronic otitis externa.

Chronic moisture is a major cause of chronic otitis externa (COE). Moisture combined with inadequate lubrication of the stratum corneum and retention of keratin debris promote bacterial and fungal growth. In most cases of COE, creating a well-aerated, dry, self-cleaning external auditory canal prevents further infection. This can usually be accomplished by medical treatment that includes suction and swabbing. Antibiotic-steroid ear drops control infection and inflammation. Alcohol flush and warm-air ventilation dry the canal, and a hydrophobic cream lubricates and seals the stratum corneum from moisture, fungus, and bacteria. An anatomic variation, a narrow external auditory meatus leading to poor ventilation, is frequently associated with COE, which does not respond to conventional therapy. A previously unreported simple lateral conchomeatoplasty is presented. No other described meatoplasty corrects both the conchal cartilage projection and inadequate meatal skin circumference which, together, cause the small meatus. The lateral conchomeatoplasty has been used by this author for over 20 years on 35 ears. All patients showed improvement; most had complete control.

Chronic Disease↗

PubMed1978

The Grimonster symposium on the occasion of the 50th anniversary of the first lumbar sympathectomy.

Under the auspices of the Belgian Surgical Society, a small group of American and European surgeons discussed in detail the place of lumbar sympathectomy in present day surgical practice. A consensus was reached concerning the physiologic effect, anatomical variations and indications for the operation. Conclusions included the questionable value of lumbar sympathectomy for treating intermittent claudication due to aortoiliac disease alone, its possible effectiveness when obliterative arterial disease is limited to the femoral popliteal segment, and its occasional beneficial effect when performed in conjunction with some reconstructive arterial operations.

Belgium↗

PubMed1980

Persistent cholecystohepatic ducts.

Anatomical variations in the biliary tract are reported with sufficient frequency to be of concern to the operating surgeon. They are often not identified prior to surgery. Drainage of both intrahepatic ducts into the gallbladder was identified in a case as the gallbladder was removed. The common bile duct proximal to the cystic duct was atretic. The problem was treated by a choledochoduodenostomy at the confluence of the hepatic ducts in the gallbladder bed.

Abnormalities, Multiple↗

PubMed1998

Genetic influence on the prevalence of torus palatinus.

Torus palatinus (TP) represents a benign anatomic variation. It has been suggested that genetic factors play a leading role in its occurrence. The purpose of the present study was to determine, by segregation analysis, the inheritance of TP. Data were collected from members of 37 randomly selected Israel Jewish families and analyzed using the segregation analysis. Vertical transmission of TP was found in 19 families suggesting autosomal dominant transmission, which was supported by the results of the segregation analysis test. A significantly higher number of affected offspring (60.3%) was observed compared to the expected figure (50%) for an autosomal dominant trait with full penetrance. This is explained by the high gene frequency of TP and the relatively high proportion of homozygous parents.

Adult↗

PubMed1997

Anatomical variant of the lateral pectoral nerve innervating the anterior portion of the deltoid muscle: a case report.

BACKGROUND: The deltoid muscle is innervated by the axillary nerve. There is no collateral nerve supply described for this muscle. Palsy of the axillary nerve is common in shoulder trauma due to its close relationship to the surgical neck of humerus. METHODS: A dissection of the pectoral and axillary regions of two female cadavers was performed bilaterally for a detailed analysis of the innervation of the deltoid muscle. RESULTS: A branch of the lateral pectoral nerve provided supplemental innervation to the anterior portion of the deltoid muscle bilaterally in both cadavers. CONCLUSION: A branch of the lateral pectoral nerve could provide collateral nerve supply to the deltoid muscle. The frequency of this anatomical variation requires further exploration.

Aged↗

PubMed1997

Erroneous pressure measurement due to artificially deformed vessel during angioplasty.

Percutaneous transluminal angioplasty is a commonly performed procedure. The clinical success of such a procedure is determined by the combination of the post-procedure angiographic appearance and the pressure gradient across the lesion. This case demonstrates the importance of recognizing the anatomical variation if proper pressure measurements are to be obtained.

Aged↗

PubMed1999

Laser treatment of symptomatic anterior pharyngeal pouches after laryngectomy.

UNLABELLED: BACKGROUND. An anterior pharyngeal pouch is a common anatomic variation after total laryngectomy. The exact part the pouch has to play in postlaryngectomy swallowing disorders is unknown but might be bigger than expected. METHODS: Nine patients with a symptomatic pouch were treated with CO2 laser and questioned about pre- and postoperative complaints. RESULTS: Eight out of nine patients noticed an obvious improvement of their swallowing complaints after laser surgery. CONCLUSION: Based on the results, it is concluded that CO2-laser treatment with division of the bar of tissue posterior to the pouch is seen as a safe and simple way to treat patients for symptoms that can be wrongly attributed to a total laryngectomy.

Aged↗

PubMed1998

Double or bifid zygomaticus major muscle: anatomy, incidence, and clinical correlation.

The anatomy of the double or bifid zygomaticus major muscle is investigated in a series of 50 hemifacial cadaver dissections. The double zygomaticus major muscle represents an anatomical variation of this muscle of facial expression. This bifid muscle originates as a single structure from the zygomatic bone. As it travels anteriorly, it then divides at the sub-zygomatic hollow into superior and inferior muscle bundles. The superior bundle inserts at the usual position above the comer of the mouth. The inferior bundle inserts into the modiolus below the corner of the mouth. The incidence of the double zygomaticus major muscle was 34% in the present study, as it was found to be present in 17 of 50 cadaver dissections. This study shows that variation in the individual morphology of the mimetic muscles can be a common finding. Clinically, the double or bifid zygomaticus major muscle may explain the formation of cheek "dimples." The inferior bundle was observed in several specimens to have a dermal attachment along its mid-portion, which tethers the overlying skin. When an individual with this anatomy smiles, traction on the skin may create a dimple due to this dermal tethering effect.

Cadaver↗

PubMed1999

Handouts as an educational support for the teaching/learning program in clinical anatomy.

Handouts were developed to support the program of Clinical Anatomy in the Medical School of Porto, and since 1996/97 alterations have been made to improve their format and content with our educational objectives in mind. A questionnaire was designed to evaluate the opinion of second-year medical students enrolled in the program. Students were asked about their approval of the way handouts were organized and their usefulness, especially for lectures and practical sessions on physical examination, sectional and imaging anatomy, anatomical variations and malformations and case studies. Of 152 students, 138 (90.8%) returned the questionnaire. To describe the relationship between the value of handouts and several aspects of their organization and adequacy, the Spearman rank correlation coefficient was used for lectures, and canonical correlation for the various practical sessions. Students fully approved the way the handouts of lectures and practical sessions were organized (81.8% and 87%, respectively), their presentation (74.6% and 86.2%), relevance (88.3% and 85.5%), usefulness in understanding the lectures (77.6%) and their value in preparing for practical sessions (83.3%). Handouts were considered highly useful for case studies (90%), physical examination (81.9%) and sectional anatomy (65.7%). Students stating a higher degree of utility of the handouts emphasized that they were useful-indeed essential-in preparing for sessions, and noted their objectivity. The evaluation of the handouts was highly favorable and showed that they can be used as a guide through the complexities of an innovative program of Clinical Anatomy.

Anatomy↗

PubMed1998

Embryology and anatomy of the rectum.

Rectal cancer surgery is difficult due to the rectum's relatively inaccessible pelvic position and its direct relation to many vital structures. The surgeon is challenged to restore intestinal continuity while working in a confined space. Despite the importance of these issues, the embryology and surgical anatomy of the rectum have been poorly understood. In recent years, cadaver dissections and operative resection under direct vision have provided a clearer picture of the structure of the rectum and mesorectum, their innervation, blood supply, and surrounding structures. New imaging techniques will shed further light on the anatomy of these structures and their anatomic variations.

Anastomosis, Surgical↗