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Histochemical localization of acetylcholinesterase in the lateral eye and brain of Limulus polyphemus: might acetylcholine be a neurotransmitter for lateral inhibition in the lateral eye?

The distribution of acetylcholinesterase (AChE) in the lateral eye and brain of the horseshoe crab was investigated with histochemical means using standard controls to eliminate butyrylcholinesterase and nonspecific staining. Intense staining was observed in the neural plexus of the lateral compound eye, in the lateral optic nerve, and in various neuropils of the brain. Nerve fibers with moderate to weak staining were widespread in the brain. No somata were stained in either the lateral eye or the brain. The distribution of acetylcholinesterase in the supraesophageal ganglia and nerves of the giant barnacle was also investigated for comparison. Although both the median optic nerve of the barnacle and the lateral optic nerve of the horseshoe crab appear to contain the fibers of histaminergic neurons, only the lateral optic nerve of the horseshoe crab shows AChE staining. Other parts of the barnacle nervous system, however, showed intense AChE staining. These results along with the histochemical controls eliminate the possibility that some molecule found in histaminergic neurons accounted for the AChE staining but support the possibility that acetylcholine might be involved as a neurotransmitter in lateral inhibition in the horseshoe crab retina. Two reasonable neurotransmitter candidates for lateral inhibition, histamine and acetylcholine, must now be investigated.

Acetylcholine↗
PubMed2000

Riluzole for amyotrophic lateral sclerosis (ALS)/motor neuron disease (MND).

BACKGROUND: Riluzole has been approved for treatment of patients with amyotrophic lateral sclerosis (ALS) in some countries but not others. Questions persist about its clinical utility because of high cost, modest efficacy and concern over adverse effects. OBJECTIVES: To examine the efficacy of riluzole in prolonging survival, and in delaying the use of surrogates (tracheostomy and mechanical ventilation) to sustain survival. SEARCH STRATEGY: Search of the Cochrane Neuromuscular Disease Group Register for randomized trials and enquiry from authors of trials and other experts in the field. The most recent search was conducted in June 1999. SELECTION CRITERIA: Types of studies: randomized trials TYPES OF PARTICIPANTS: adults with a diagnosis of ALS Types of interventions: treatment with riluzole or placebo Types of outcome measures: Primary: per cent mortality at 12 months with riluzole 100 mg Secondary: per cent mortality as a function of time with 100 mg and with all doses of riluzole, scales of neurologic function, quality of life, muscle strength and adverse events. DATA COLLECTION AND ANALYSIS: We identified two randomized trials. Each reviewer graded them for methodological quality. Data extraction was performed by a single reviewer and checked by the other two. We obtained some missing data from investigators. We performed meta-analyses with RevMan software using a fixed effects model. MAIN RESULTS: The two eligible trials included a total of 794 riluzole treated patients and 320 placebo treated patients. The methodological quality was acceptable and the trials were easily comparable. There were significant differences between the riluzole and placebo groups of both trials, in terms of the primary outcome measure, which was per cent mortality at 12 months with the 100 mg dose of riluzole. The odds ratio for the combined studies was 0.57 (95%CI 0.41 to 0.80) at 12 months. In the secondary outcome measures, there was a survival advantage with riluzole 100 mg at six, nine, 12 and 15 months, but not at three or 18 months. Pooled data from the 50, 100 and 200mg dose groups in the larger trial showed a lower per cent mortality with riluzole compared to placebo only at 12 months (odds ratio (OR) 0.64, 95% CI 0.47 to 0.88). There was no beneficial effect on bulbar function, or muscle strength. There were scant data on quality of life, but patients treated with riluzole remained in a more moderately affected health state significantly longer than placebo-treated patients (weighted mean difference (WMD) 35.5 days, 95% CI 5.9 to 65. 0). A threefold increase in serum alanine transferase was more frequent in riluzole treated patients than controls (WMD 2.65, 95% CI 1.51 to 4.65). REVIEWER'S CONCLUSIONS: Riluzole 100 mg per day appears to be modestly effective in prolonging survival for patients with ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1995

Efferent connections of the lateral cortex of the lizard Gekko gecko: evidence for separate origins of medial and lateral pathways from the lateral cortex to the hypothalamus.

The lateral cortex of the lizard Gekko gecko is composed of three parts: a dorsal and ventral part located rostrally and a posterior part located caudally. In order to obtain detailed information about the efferent connections of these lateral cortex subdivisions, iontophoretic injections of the anterograde tracers Phaseolus vulgaris leucoagglutinin and biotinylated dextran were made in the various parts. The main projection from the dorsal part terminates in the caudal part of the medial cortex. Other cortical projections were noted to the ipsi- and contralateral lateral cortex, the large-celled part of the medial cortex, and the dorsal cortex. Additional fibers were found bilaterally in the anterior olfactory nucleus and the external amygdaloid nucleus. The ventral part of the lateral cortex projects mainly to the ipsilateral, posterior part of the dorsal ventricular ridge and the external amygdaloid nucleus. Minor contralateral projections to these nuclei were also found. Other projections were observed to travel to the caudal part of the medial cortex, to the nucleus sphericus, and bilaterally to the lateral cortex and the anterior olfactory nucleus. The posterior part of the lateral cortex has similar efferent connections as the dorsal part and should be regarded as the caudal continuation of the dorsal part. Because previous studies have shown that the medial cortex and the amygdaloid complex project to different hypothalamic areas, we conclude that the dorsal and ventral parts of the lateral cortex transmit olfactory information to separate hypothalamic areas that are probably involved with different types of behavior.

Animals↗
PubMed1989

Lateral facet syndrome of the patella. Lateral restraint analysis and use of lateral resection.

Thirty-eight knees in 34 patients with an average age of 22 years were diagnosed as having lateral facet syndrome (LFS), a painful compressive arthropathy of the lateral facet of the patella. This diagnosis was based on the physical findings of tenderness at the lateral patellofemoral joint line, tenderness over the vastus lateralis obliquus (VLO) tendon just above the patella, a positive medial apprehension test, and marked resistance to medial patellar displacement with the knee flexed 30 degrees. The most common complaints were patellar pain with activity, pain with prolonged knee flexion, intermittent knee swelling, and giving way. At surgery, the VLO, the lateral retinaculum (LR), and the anterior fibers of the iliotibial tract (ITT) were sequentially divided from the lateral border of the patella. Each was temporarily reattached to a cuff of soft tissue left on the patella using surgical clamps to determine its contribution to lateral restraint. The VLO was found to be the primary restraint in one-half of the knees. In one-third of the knees, all three of the structures contributed equally. In six knees, the primary restraint was the anterior fibers of the ITT, whereas the LR was the primary restraint in only two. The distal ends of these three structures were then resected to prevent rescarring and retethering. At a minimum follow-up period of two years, 87% had satisfactory relief of their patellar pain, had returned to normal activities, and had no or minimal physical findings of LFS. The procedure is recommended for patients who have failed other procedures and in those whose symptoms cannot be controlled by activity modification, exercises, bracing, or medication.

Adolescent↗
PubMed2000

Nerve blocks (subcostal, lateral cutaneous, femoral, triple, psoas) for hip fractures.

BACKGROUND: Various nerve blocks using local anaesthetic agents have been used in order to reduce pain after hip fracture. OBJECTIVES: To determine the effects of nerve blocks (inserted either pre-operatively, operatively or post-operatively) as part of the treatment for a hip fracture. SEARCH STRATEGY: The Cochrane Musculoskeletal Injuries Group trials register, MEDLINE, and bibliographies of trial reports were searched. Date of the most recent search: April 1998. SELECTION CRITERIA: Randomised and quasi-randomised trials involving the use of nerve blocks as part of the care of a hip fracture patient. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality, by use of an eight item scale, and extracted data. Wherever appropriate, results of outcome measures were pooled. MAIN RESULTS: Six randomised or quasi-randomised trials involving 229 patients were included. One trial related to insertion of a nerve block pre-operatively and the remaining five, to peri-operative insertion. Nerve blocks resulted in a reduction of the quantity of parental or oral analgesia administered to control pain from the fracture/operation or during surgery. It was not possible to demonstrate if this reduction in analgesia use was associated with any clinical benefit. REVIEWER'S CONCLUSIONS: Because of the small number of patients included in this review and the differing type of nerve blocks and timing of insertion, it is not possible to determine if nerve blocks confer any benefit when compared with other analgesic methods as part of the treatment of a hip fracture. Further trials with larger numbers of patients and full reporting of clinical outcomes would be justified.

Hip Fractures↗
PubMed1998

Spatial frequency processing in posteromedial lateral suprasylvian cortex does not depend on the projections from the striate-recipient zone of the cat's lateral posterior-pulvinar complex.

It is generally considered that the posteromedial part of the cat's lateral suprasylvian cortex is involved in the analysis of image motion. The main afferents of the posteromedial lateral suprasylvian cortex come from a direct retinogeniculate pathway and indirect retinotectal and retino-geniculo-cortical pathways. Removal of the primary visual cortex does not affect the spatial and temporal processing of suprasylvian cortex cells suggesting that these properties are derived from thalamic input. We have investigated the possibility that the striate-recipient zone of the lateral posterior nucleus-pulvinar complex may be responsible for the spatial (and temporal) frequency processing in posteromedial lateral suprasylvian cortex since these two regions establish strong bidirectional connections and share many visual properties. Experiments were done on anaesthetized normal adult cats. Visual responses in suprasylvian cortex were recorded before, during, and after the deactivation of the lateral part of the lateral posterior nucleus accomplished by the injection of lidocaine or GABA. Results can be summarized as follows. A total of 64 cells was tested. Out of this number, 11 units were affected by the deactivation of the lateral part of lateral posterior nucleus and one cell, by the blockade of pulvinar. For all cells, except one, the effect consisted in a global reduction of the evoked discharge rate suggesting that the thalamo-suprasylvian cortex projections are excitatory in nature. We did not find any significant differences in the optimal spatial frequency, nor in the width of the tuning function, whether the grating was presented at half- or saturation contrast. In addition, there were no significant differences between the low- and high cut-off spatial frequency values computed before and after the deactivation of the lateral posterior nucleus. No specific changes were observed in the contrast sensitivity function of the posteromedial lateral suprasylvian cortex cells. Similar results were observed with respect to the temporal frequency tuning functions. Deactivating the lateral posterior nucleus did not modify the direction selectivity nor the organization of the subregions of the lateral suprasylvian cortex "classical" receptive fields. The absence of strong changes in posteromedial lateral suprasylvian cortex cell response properties following the functional blockade of the lateral posterior nucleus suggests that the projections from this part of the thalamus are not essential to generate the spatial characteristics of most posteromedial lateral suprasylvian cortex receptive fields. These properties may be derived from other thalamic inputs (e.g., medial interlaminar nucleus) and/or from the intrinsic computation of the afferent signals within the lateral suprasylvian cortex. On the other hand, it is possible that the lateral posterior nucleus lateral suprasylvian cortex loop may be involved in other functions such as the analysis of complex motion as suggested by the findings from our and other groups.

Animals↗
PubMed1997

[Prevention of hemorrhagic complications in the lateral retinacular section of the patella. A study of the lateral arteries of the knee applied to the prevention of knee hemarthrosis].

PURPOSE OF THE STUDY: Arthroscopic lateral retinacular release is one of the most employed procedures for patellar chondromalacia. A literature review show a complication rate of 10 to 18 p. 100 of postoperative hemarthrosis. This work aims to study the vessels anatomy of the lateral side of the knee in order to find anatomical landmarks allowing to avoid or coagulate them. MATERIAL AND METHODS: Thirty-three cadaver knees were dissected. Measures were made related to the lateral superior genicular artery and the lateral inferior genicular artery. A study using tracing-paper was also carried out. The main part of the work was more descriptive, studying anastomosis between the different arteries and veins location. RESULTS: Concerning the lateral superior genicular artery, measure analysis showed that this artery was always cut in lateral patellar retinaculum. This artery never runs more than one centimeter proximally to the base of patella, which is too insufficient to escape from lateral retinacular release. We noted the possibility of locating 90 p. 100 of lateral superior genicular arteries in a minimal distance of 15 mm, in front of the lateral proximal angle of the patella. Concerning the lateral inferior genicular artery, only a few arteries, protected in the meniscal wall in its early course, can remain intact. Two thirds of these arteries are very vulnerable running across the lateral side of the knee. The study of the tracing-papers confirmed topographic study measurements. The descriptive study emphasized the number and the importance of anastomoses between these different arteries. Each artery is flanked by two large satellite veins, which also attribute a veinous origin to a possible bleeding. DISCUSSION: The topographic study of the lateral inferior genicular vessels shows that their course varies. It seems necessary to avoid their division by performing the standard anterior lateral inferior arthroscopic portal proximally to these vessels. This can be realized at the beginning of the procedure through cutaneous transillumination. The lateral superior genicular vessels are always cut. They are nevertheless reachable through a small lateral incision of about 10 mm, distally to the lateral superior angle of the patella. 90 p. 100 at least of these arteries could be coagulated in such a way. We also emphasize the use of classical methods for the prevention of excessive venous bleeding, such as a compression dressing. CONCLUSION: Following this anatomical study, we suggest, as a supplementary precaution, a selective hemostasis of the lateral superior genicular vessels through a small incision associated with the location of the lateral inferior genicular vessels by cutaneous transillumination.

Arthroscopy↗
PubMed1999

MR imaging findings of lateral ulnar collateral ligament abnormalities in patients with lateral epicondylitis.

OBJECTIVE: The purpose of this paper was to use MR imaging to determine whether a relationship exists between lateral epicondylitis and abnormalities of the lateral ulnar collateral ligament. SUBJECTS AND METHODS: The study group comprised 35 consecutive patients who were referred for MR imaging to rule out lateral epicondylitis. On MR imaging, "lateral epicondylitis" was defined as increased signal intensity of the extensor tendons close to their insertion on the lateral epicondyle. The severity of the lateral epicondylitis was graded as mild, moderate, or severe. The origin of the lateral collateral ligamentous complex was characterized, and the lateral ulnar collateral ligament was graded as normal, thickened, partially torn, or torn. Eleven patients underwent elbow surgery after the initial MR examination. RESULTS: In 15 patients, MR imaging revealed characteristics of mild lateral epicondylitis. In 13 of these patients, the lateral ulnar collateral ligament was normal; one patient showed a thickened ligament; and one patient had a thinned ligament. In 11 patients, MR imaging showed features of moderate lateral epicondylitis. In eight of these patients, the lateral ulnar collateral ligament was thickened, and in the remaining three patients the ligament was normal. All nine patients with severe lateral epicondylitis showed abnormalities of the lateral ulnar collateral ligament on MR imaging. In one of these patients the lateral ulnar collateral ligament was thickened, in three patients we saw a partial tear, and in the remaining five patients we saw a complete tear of the ligament. CONCLUSION: In our study, MR imaging features of lateral epicondylitis were often associated with thickening and tears of the lateral ulnar collateral ligament.

Adult↗
PubMed1994

Efferent connections from the lateral hypothalamic region and the lateral preoptic area to the hypothalamic paraventricular nucleus of the rat.

The lateral preoptic and lateral hypothalamic regions contain the majority of the cell groups embedded in the fibre trajectories of the medial forebrain bundle on its course through the hypothalamus. Recent studies have extended considerably the parcellation of the lateral hypothalamic region, and therefore, the need to emphasize new insights into the anatomical organisation of projections from the neurons of the lateral hypothalamic region. In the present study we describe the anatomical organisation of efferent projections from the lateral preoptic and lateral hypothalamic regions to the hypothalamic paraventricular nucleus (PVN) on the basis of retrograde- and anterograde-tracing techniques. Iontophoretic injections of the retrograde tracer, cholera toxin subunit B, into the PVN revealed that most hypothalamic nuclei project to the PVN. Within the lateral hypothalamic region, retrogradely labelled cells were concentrated in the intermediate hypothalamic area, the lateral hypothalamic area, and the perifornical nucleus, whereas fewer retrogradely labelled cells were found in the lateral preoptic area. To determine the distribution of terminating fibres in subnuclei of the heterogeneous PVN, iontophoretic injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin were delivered into distinct areas of the lateral hypothalamic region. Neurons of the intermediate hypothalamic area projected mainly to the PVN subnuclei, which contained parvicellular neuroendocrine cells. In contrast, neurons of the rostral and tuberal parts of the lateral hypothalamic area and the perifornical nucleus projected to the PVN subnuclei, which contained parvicellular neurons that send descending projections to preganglionic cell groups in the medulla and spinal cord. The perifornical nucleus was the only area within the lateral hypothalamic region that consistently innervated magnocellular perikarya of the PVN. Finally, all areas of the lateral hypothalamic region contributed substantially to fibres terminating in the perinuclear shell of the PVN. These results demonstrate that anatomically distinct areas of the lateral hypothalamic region have distinct projections to subnuclei of the PVN and further substantiate the view that the lateral hypothalamic region as well as the PVN constitute anatomically and functionally heterogeneous structures.

Animals↗
PubMed1999

Lateral reach: a clinical measure of medio-lateral postural stability.

BACKGROUND AND PURPOSE: Medio-lateral postural instability has recently been identified as a risk factor for falls in the elderly community-dwelling population. However, few clinical tests involve challenges to stability limits in the medio-lateral direction. A lateral reach test was thus developed. Preliminary evaluation of the symmetry, accuracy, test-retest repeatability, and construct validity of the lateral reach test was undertaken to ensure its validity and repeatability prior to clinical application. METHOD: Sixty healthy older female subjects (aged 72.5 +/- 5 years) participated in this study which involved two tasks. The first was the clinical test: a maximal lateral reach to the right and left, recorded by a clinical measure (observation of hand excursion) and a laboratory measure (3D analysis of hand marker excursion). The second was the recording of centre of pressure (COP) stability limits in the lateral direction by use of a dual force platform system. Eighteen subjects returned for repeatability testing. RESULTS: No significant differences in the measures were found between the sides. Lateral reach as measured by the clinical measure was significantly (p < 0.05) correlated with both the laboratory measure of reach (r = 0.650) and with COP stability limits (r = 0.331). The clinical measure of reach was not significantly different (p > 0.01) from the laboratory measure. High test-retest repeatability (r > 0.94) was found for all measures. CONCLUSIONS: The clinical lateral reach test was found to be an accurate measure of lateral reach ability. As it was significantly correlated with COP excursion it was deemed a valid indicator of lateral stability limits. In addition, the lateral reach test had high test-retest repeatability and was symmetrical between the sides. These promising results support both it's use where a clinical indicator of medio-lateral postural stability is desired and further investigation of the lateral reach test in clinical populations.

Aged↗
PubMed1978

Lateralization in normal 6-year-olds as related to later reading disability.

The differentiation of lateral preference in hand, eye, ear, and foot was measured in 110 normal Grade 1 children and reading achievement was tested 3 and 5 years later. No support was found for the widely held belief that delays in early lateralization underlie subsequent reading impairment. Paradoxically, boys with serious reading disability showed a strong degree of early lateral concordance. Male, impaired readers displayed a tendency when they were in Grade 1 to be either uniformly right- or left-preferring across all 4 sensory-motor modalities. The results contradict the popular notion that lateral usage emerges from an undifferentiated state in the direction of greater degrees of specialization. Lateralization may be an expression of reflex constraints bound initially to the infant's tonic-neck posture, with later development less reflex-patterned during the acquisition of more sophisticated information-processing strategies. Such an interpretation implies a progressive discontinuity between lateral usage and neuro-maturational processes. Alternatively, the results can be accounted for by (1) a new maturational delay model in which maturation-dependent lateralization proceeds in graduated stages from a highly specialized beginning toward greater levels of neuromotor integration; or (2) a model that maintains the notion of emergent lateralization but in which delays in the lateralization process are actually beneficial to later performance.

Achievement↗
PubMed2002

The superficial lateral canthal tendon: anatomic study and clinical application to lateral canthopexy.

Most patients who undergo facial cosmetic surgery procedures that could cause lower eyelid retraction or ectropion should have an additional surgical procedure to support the lower eyelid and lateral canthus. The lower eyelid should be supported when performing laser planing of the eyelid; midface elevation through a lower eyelid incision approach; or conventional blepharoplasty, in patients with lower eyelid laxity. Suspending the lateral canthus by surgically altering the lateral canthal tendon is a proven technique that can provide support for the lower eyelid. However, a technique of this complexity may be unnecessary for most cosmetic surgery patients. To increase understanding of the fascial support system of the lateral canthus, four fresh cadaver dissections were performed to investigate the attachments of the lateral canthus to the lateral orbital rim. The most commonly appreciated attachment between the eyelids and the lateral orbital rim is the lateral canthal tendon (the lateral canthal raphe). However, the lateral canthus also is attached to the orbital rim at a more superficial level through the septum orbitale. This superficial fascial plane may be modified and used as a structure to stabilize or suspend the lateral canthus. This structure is defined in this article as the "superficial lateral canthal tendon."

Cadaver↗
PubMed1998

Lateral radiologic evaluation of lateral mass screw placement in the cervical spine.

STUDY DESIGN: Assessment of the value of lateral radiographs in evaluation of lateral mass screw placement in the cervical spine. OBJECTIVES: To assess the value of lateral radiographs in determining the safe or hazardous locations of the tips of screws used in lateral mass screw fixation. SUMMARY OF BACKGROUND DATA: Posterior plating with lateral mass screw fixation is frequently used to stabilize the cervical spine and improve fusion. Injury to the spinal nerves caused by screws that are too long must be identified quickly to minimize neurologic complication. No previous radiologic study in which lateral mass screw placement was evaluated using lateral radiographs has been reported. METHODS: Six cervical spines were removed from embalmed cadavers. Three screws using the Roy-Camille technique and another three using Magerl technique were placed into the lateral mass at C3-C5 in each specimen. Four screw placements under direct visualization, including placement of the screw tip staying the ventral cortex and 2-mm, 4-mm, and 6-mm overpenetration of the ventral cortex, were performed separately on each specimen for each of the two techniques. After each placement, a lateral radiograph was taken. Each vertebral body was divided vertically into four equal zones with Zone I the most posterior. Another equal zone, posterior to the posterior border of the vertebral body was defined as pre-Zone I. The number of screw tips seen in each zone were quantified for each placement. RESULTS: In the screws placed using the Roy-Camille technique, 77.8% of screws placed without perforating the ventral cortex were found in Zone I; 72.2% placed with 2-mm overpenetration of the ventral cortex were noted in Zone II; and 61.1% of the screws with 4-mm overpenetration of ventral cortex and 77.8% with 6-mm overpenetration were located in Zone III. For the use of the Magerl technique, 44.4% of the screws placed without perforating the ventral cortex were found in pre-Zone I; 72.2% of the screws placed with 2-mm overpenetration were located in Zone I; and 66.6% with 4-mm overpenetration and 89.7% with 6-mm overpenetration were noted in Zones I and II, respectively. CONCLUSIONS: Lateral radiographs may be valuable in evaluating lateral mass screw placement. Ideal screw tip positions on lateral radiograph for the Roy-Camille technique may be in Zone I, and for the Magerl technique may be in pre-Zone I.

Aged↗
PubMed2003

Comparison of the far lateral and extreme lateral variants of the atlanto-occipital transarticular approach to anterior extradural lesions of the craniovertebral junction.

OBJECTIVE: Managing lesions situated in the anterior aspect of the craniovertebral junction (CVJ) remains a challenging neurosurgical problem. The purposes of this study were to examine the microsurgical anatomy of the anterior extradural aspect of the CVJ and the differences in the exposure obtained by the far lateral and extreme lateral atlanto-occipital transarticular approaches. The far lateral approach, as originally described, is a lateral suboccipital approach directed behind the sternocleidomastoid muscle and the vertebral artery and just medial to the occipital and atlantal condyles and the atlanto-occipital joint. The extreme lateral approach, as originally described, is a direct lateral approach deep to the anterior part of the sternocleidomastoid muscle and behind the internal jugular vein along the front of the vertebral artery. Both approaches permit drilling of the condyles at the atlanto-occipital joint but provide a different exposure because of the differences in the direction of the approach. METHODS: Fifteen adult cadaveric specimens were studied using a magnification of x3 to x40 after perfusion of the arteries and veins with colored silicone. The microsurgical anatomy of the extradural aspects of the CVJ and the two atlanto-occipital transarticular approaches were examined in stepwise dissections. RESULTS: The far lateral atlanto-occipital transarticular approach provides excellent exposure of the extradural lesions located in the ipsilateral anterior and anterolateral aspects of the extradural region of the CVJ. The extreme lateral atlanto-occipital transarticular approach provides excellent exposure, not only on the side of the exposure, but also extending across the midline to the medial aspect of the contralateral atlanto-occipital joint and the lower clivus. CONCLUSION: The far lateral and extreme lateral variants of the atlanto-occipital transarticular approach provide an alternative to the transoral approach to the anterior extradural structures at the CVJ. Compared with the transoral approach, both approaches provide a shorter operative route, avoid the contaminated nasopharynx, reduce the incidence of cerebrospinal fluid leak, and are not limited laterally by the atlanto-occipital joint.

Adult↗
PubMed1996

Development of projections from transplants of embryonic medial or lateral frontal cortex placed in the lateral frontal cortex of newborn hosts.

Several recent experiments using neocortical transplantation paradigms indicated that embryonic neurons grafted in a heterotopic locus retain development characteristics corresponding to their site of origin. In the present study, limited portions of lateral (lateral-to-lateral) or medial (medial-to-lateral) sectors of embryonic (E16) frontal cortex were grafted into the lateral frontal cortex of newborn rats. A retrograde tracer was injected 3-4 months later into the dorsomedial or ventrolateral sectors of the host caudate-putamen (CPU). The results indicate that the mediolateral arrangement of striatal projection developed by lateral-to-lateral transplants is virtually identical to that found in intact rats. A very weak proportion of the transplanted cells distribute fibers to the dorsomedial sector of the CPU. In marked contrast, the proportion of efferents from medial-to-lateral transplants projecting to the dorsomedial CPU is by far larger than the one directed to the ventrolateral CPU. Our findings provide evidence that even within one single neocortical area (the frontal neocortex) some degree of prespecification (medial versus lateral patterns of efferent projections) is already present at E16.

Age Factors↗
PubMed1985

Lateral border zone: quantitation of lateral extension of subendocardial infarction in the dog.

This study was undertaken to quantitate the lateral extension that occurs concomitantly with the transmural extension of a subendocardial infarction. A subendocardial infarct was produced in 12 dogs by a 40 minute temporary coronary artery occlusion. Infarct extension was induced 7 days later by permanent occlusion of the same vessel. Regional myocardial blood flows confirmed that ischemia had been produced with both coronary artery occlusions. The vascular boundaries between the normally perfused and ischemic beds were defined by perfusion with different-colored Microfil solutions. The extent of subendocardial infarction and subsequent transmural and lateral extensions were assessed by point counting of histologic specimens. The initial temporary occlusion produced a 30.0 +/- 4.2% transmural infarct and the subsequent permanent occlusion a 29.2 +/- 3.5% transmural extension in a risk region of 39 +/- 4 g. Lateral extension was not measured in four dogs because the initial subendocardial infarct was patchy with markedly irregular lateral borders. In eight dogs the size of the measured lateral infarct extension from each lateral margin from two histologic sections was 0.63 +/- 0.013 cm2. The area of both lateral extensions was 1.7 +/- 0.1% of the cross-sectional area of its risk region as determined by planimetry. Using a model of the risk region, the mass of the lateral extension was estimated to be 1.4 +/- 0.3 g or 3.5 +/- 0.6% of the region at risk. Thus, at the lateral margin of a subendocardial infarct there is a border zone that is small relative to the size of the region at risk and infarcted myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Strabismus after balanced medial plus lateral wall versus lateral wall only orbital decompression for dysthyroid orbitopathy.

PURPOSE: This study aimed to determine the relative incidence and time course of new-onset strabismus after balanced medial plus lateral wall orbital decompression versus decompression of the lateral wall alone for dysthyroid orbitopathy. METHODS: The study design was a retrospective nonrandomized comparative case series. Thirty-two consecutive patients underwent balanced medial plus lateral wall orbital decompression or lateral wall orbital decompression for dysthyroid orbitopathy. The incidence, duration, and treatment of postoperative strabismus was recorded for each patient. RESULTS: Significant preoperative strabismus was present in 31% (4/13 patients) of the balanced decompression group and in 26% (5/19 patients) of the lateral wall decompression group. Only 25% (1/4) of cases of preexisting strabismus in the balanced decompression group resolved postoperatively without muscle surgery, whereas 60% (3/5) of cases in the lateral wall decompression group resolved postoperatively without surgery. Preoperative strabismus was absent in 69% (9/13) of patients in the balanced decompression group and in 74% (14/19) of patients in the lateral wall decompression group. New-onset, persistent postoperative strabismus developed in 33% (3/9) of patients in the balanced decompression group and in 7% (1/14) of patients in the lateral wall decompression group. CONCLUSION: Lateral wall orbital decompression may produce less new-onset, persistent postoperative strabismus than balanced medial plus lateral wall orbital decompression for dysthyroid orbitopathy.

Adult↗
PubMed1994

Quantitative morphology of the lateral ligaments of the spine. Assessment of their importance in maintaining lateral stability.

STUDY DESIGN: This study used human cadaveric material to examine the three-dimensional morphology and biomechanics of the superior and lateral costotransverse ligaments and the intertransverse ligament of the spine. OBJECTIVES: To provide descriptive and quantitative data on the morphology of the lateral ligaments of the spine and to assess their importance in maintaining lateral stability, especially regarding the pathogenesis of idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Ligaments have been reported as being able to stabilize the spine by mechanical constraint and by neurologic feed-back. Midline spinal ligaments have been well studied but do not appear to be effective in maintaining lateral stability because of their sites of attachment. Lateral ligaments of the spine have not been adequately documented in the literature. METHODS: The morphology, sites of attachment, and dimensions of the superior costotransverse ligament, lateral costotransverse ligament, and intertransverse ligament from thoracic level 7 to thoracic level 10 were determined on 32 human cadavers. RESULTS: The intertransverse ligament was found not to be a true ligament. The lateral costotransverse ligament was a true ligament but did not have the characteristics appropriate for involvement in lateral stability. The superior costotransverse ligament also was a true ligament and had all of the characteristics appropriate for involvement in the active lateral balancing of the spine. CONCLUSIONS: In contrast to the midline ligaments of the spine, the superior costotransverse ligament perhaps is the most important ligament for active lateral balancing of the spine and warrants further study, particularly regarding the development of idiopathic scoliosis.

Aged↗