Proximal femoral nail for treatment of trochanteric femoral fractures.

PURPOSE: To report outcomes of 87 consecutive patients treated with a proximal femoral nail (PFN) for trochanteric femoral fractures. METHODS: 17 men and 70 women aged 58 to 95 (mean, 85) years with trochanteric femoral fractures underwent PFN fixation using an intramedullary nail, a lag screw, and a hip pin. Fractures were classified according to the AO system; the most common fracture type was A2 (n=45), followed by A1 (n=36) and A3 (n=6). The position of the lag screw within the femoral head was measured. The lateral slide of the lag screw after fracture consolidation was measured by comparing the immediate postoperative and final anteroposterior radiographs. RESULTS: 90% of lag screws were placed in an optimal position. The length of lateral slide of the lag screw in stable A1 fractures was significantly less than that in unstable A2 fractures; it was over 10 mm in 7 of 45 patients with A2 fractures. Cut-out of lag screw did not occur, suggesting that free sliding of the lag screw facilitates direct impaction between fragments. CONCLUSION: A PFN is useful for the treatment of trochanteric femoral fractures.

Characterization of thermal hyperalgesia, c-fos expression, and alterations in neuropeptides after mechanical irritation of the dorsal root ganglion.

STUDY DESIGN: This study analyzed hypersensitization in sensory systems after mechanical irritation of the dorsal root ganglion. OBJECTIVES: To develop a reliable and reproducible animal model of hyperalgesia arising from the dorsal root ganglion and to understand the unique contributions of the dorsal root ganglion to clinical manifestations of sciatica. SUMMARY OF BACKGROUND DATA: The dorsal root ganglion likely plays an important role in disorders of sciatica. However, no previous study has analyzed sciatica after irritation of the dorsal root ganglion. Thermal hyperalgesia indicates a decrease in thermal nociceptive threshold and hypersensitization in sensory systems. METHODS: The left L4 and L5 dorsal root ganglia in rats (n = 22) were exposed circumferentially. Other rats (n = 22) also had the left L4 and L5 dorsal root ganglia ligated loosely with two 4-0 chromic gut sutures. Changes in thermal withdrawal latency were examined in the hindpaws across time. Substance P and vasoactive intestinal polypeptide contents were quantified in the dorsal root ganglion and spinal cord. Substance P, calcitonin gene-related peptide, and c-fos expression also were examined in the spinal cord by immunohistochemistry. In addition, histologic changes in myelinated nerve content were examined in the dorsal root ganglion. RESULTS: Thermal hyperalgesia occurred in rats with exposure of the dorsal root ganglion and in rats with loose ligation of the dorsal root ganglion, and was accompanied by an increase in c-fos expression and spontaneous pain-related behaviors. CONCLUSIONS: This experimental model reliably produced a disorder resembling an acute phase sciatica and should help further advance the understanding of pathomechanisms of spinal pain after irritation of the dorsal root ganglion in humans.

Experimental lumbar radiculopathy. Behavioral and histologic changes in a model of radicular pain after spinal nerve root irritation with chromic gut ligatures in the rat.

OBJECTIVE: The recently proposed animal model of lumbar radiculopathy was used to investigate behavioral consequences and histologic changes in spinal nerve roots, dorsal root ganglia, and spinal nerves after the L4, L5, and L6 nerve roots were loosely ligated with either silk or chromic gut sutures in an attempt to better understand the pathophysiologic mechanisms that give rise to pain associated with lumbar radiculopathy. SUMMARY OF BACKGROUND DATA: Little is known about the pathophysiologic mechanisms that give rise to pain associated with lumbar radiculopathy. The recently proposed animal model of unilateral lumbar radiculopathy, which demonstrated an association with motor paresis and thermal hyperalgesia of the affected hind limb and showed evidence of spontaneous pain has been demonstrated, may serve as a vehicle to allow direct investigation of the nature of the pathophysiological mechanisms associated with lumbar radiculopathy. METHODS: Three distinct treatments of the nerve roots were initially investigated: 1) a sham intervention, where the surgery simply exposed the nerve roots and dorsal root ganglion followed by standard closing procedures; 2) 4-0 silk ligature, where two loose ligatures of 4-0 silk were placed around the nerve roots; and 3) 4-0 chromic gut 2, where four 0.3 cm pieces of 4-0 chromic gut were laid adjacent to the nerve roots and secured by two loose ligatures of 4-0 chromic gut. STUDY DESIGN: ANOVA techniques were used to test for differential effects across time for the three treatment groups in terms of animal function. A qualitative analysis of the histology of the ipsilateral and contralateral nerve roots, dorsal root ganglia, and spinal nerves was done to correlate histologic changes with behavioral changes. RESULTS: Behavioral results were consistent with the previous study. Rats treated with chromic gut, but not silk, reliably demonstrated a prolonged thermal hyperalgesia that was maximal 2 weeks after surgery and lasted for up to 12 weeks. These behavioral changes, however, were not correlated with histologic changes in myelinated fiber content in the L4, L5, and L6 nerve roots, dorsal root ganglia and spinal nerves, the ipsilateral spinal nerved, dorsal root ganglia, and nerve roots of rates ligated with silk or chromic gut showed similar, significant, decreased in the number of large diameter myelinated fibers. CONCLUSIONS: These results suggest that mechanical constriction of the L4, L5, and L6 spinal nerve roots, as evidenced by a loss of myelinated fibers, is not sufficient to produce the behavioral effects associated with this model of lumbar radiculopathy. It is hypothesized that chemical factors from the chromic gut play a role in the pathophysiology and development of the behavioral, but not histological, changes in this model of lumbar radiculopathy.

Experimental lumbar radiculopathy. Immunohistochemical and quantitative demonstrations of pain induced by lumbar nerve root irritation of the rat.

OBJECTIVE: A series of experiments were designed to develop and validate an animal model of lumbar radiculopathy. More specifically, these investigations introduced a model of chronic neuropathic pain in the rat associated with clinically relevant lumbar nerve root trauma and evaluated the ability of the model to effect symptoms and begin to understand the underlying neurochemical and neurophysiologic factors associated with these neurologic abnormalities. SUMMARY OF BACKGROUND DATA: A search of the literature suggested that these studies were a first attempt to distinguish and elucidate an experimental lumbar radiculopathy. METHODS: Two basic approaches to nerve trauma were considered, direct damage to the nerve via compression, and introduction of foreign materials in proximity to the nerve root that might cause irritation and inflammation leading to chronic symptoms. Ligature around the nerve (i.e., surrounding the nerve with a suture) was considered a plausible irritant that might behave in an animal model in a similar way that nerve root entrapment, often observed in HNP and stenosis cases, might function in humans. Further, varying levels of irritation was modeled by using 4-0 silk as a mild and 4-0 chromic gut as a more harsh irritant. STUDY DESIGN: Five distinct treatments of the nerve roots were investigated initially: 1) a sham intervention, where the surgery simply exposed the nerve roots and dorsal root ganglion followed by standard closing procedures; 2) nerve root clipping, where the nerve roots were clipped with a microhemoclip; 3) 4-0 silk ligature, where two loose ligatures of 4-0 silk were placed around the nerve roots; 4) 4-0 chromic gut 1, where one loose ligature of 4-0 chromic gut was placed around the nerve roots; and 5) 4-0 chromic gut 2, where four 0.3 cm pieces of 4-0 chromic gut were laid adjacent to the nerve roots and secured by two loose ligatures of 4-0 chromic gut. ANOVA techniques were used to test for differential effects across time for the five treatment groups in terms of animal function and biochemistry in the DRG. RESULTS: Rats treated with chromic gut ligature in large quantity demonstrated differential patterns of results on the injured and noninjured sides consistent with a lumbar radiculopathy. The injured side demonstrated significantly worse thermal hyperalgesia related to neuropathic pain (P < 0.0001); initial mechanical hypoalgesia (P < .001), and motor dysfunction (P < .001) resolving within 2 weeks; significantly increased c-fos counts (P < .0001) 2 weeks postoperatively, which showed a consistent trend toward baseline and return to baseline by 12 weeks; significantly greater and highly increased VIP concentrations in the dorsal root ganglia 2 weeks postoperatively (P < .0001) that did not resolve or tend towards baseline after 12 weeks of follow-up in conjunction with a trend toward VIP depletion in the spinal cord 2 weeks postoperatively that did resolve to baseline until a 12-week concentration indicated a significant increase in concentration (P < .002). Quantitative and qualitative changes in c-fos and VIP, correlated with the patterns of behavior and function. Thus, for the first time, evidence to link outcome behaviors and function with underlying neurochemical processes is suggested. CONCLUSIONS: When the same apparent conditions can be demonstrated in some situations to be causing pain and in other situations to be independent of pain, some additional factor or factors not considered in the original investigations may be mediating the outcome. Neurochemical consequences of nerve root irritation provide a theoretical framework for hypothesizing about various types of mediating events that might explain how similar apparent pathology might reasonably lead to different predictions about behavior consequences of the pathology.(ABSTRACT TRUNCATED AT 400 WORDS)

Topographic differences of 1H-NMR relaxation times (T1, T2) in the normal intervertebral disc and its relationship to water content.

1H-nuclear magnetic resonance studies, in vitro, on normal intervertebral discs dissected from adult bovine (3- or 4-year-old) coccygeal vertebrae were performed to clarify topographic differences in relaxation times (T1, T2) and relationships between the relaxation times and water content. Immediately after death, intervertebral discs were dissected from 1st/2nd and 2nd/3rd coccygeal vertebrae and divided into three specimens: the nucleus pulposus, inner anulus fibrosus, and outer anulus fibrosus. T1, T2, and water content were measured for the specimens collected from 15 intervertebral discs (untreated group). Secondly, specimens were similarly collected from 12 intervertebral discs and were treated to changed water contents (dehydrated group and hydrated group). For each treated specimen, T1, T2, and water content were measured. The results showed highly significant differences (P < 0.01) in T1 values among the nucleus pulposus, inner anulus fibrosus, and outer anulus fibrosus, and also in T2 values between the nucleus pulposus and anulus fibrosus. In each of the nucleus pulposus and anulus fibrosus, a positive linear relationship (r = 0.97, P < 0.01) was found between T1 and water content. The respective regression lines for the nucleus pulposus and anulus fibrosus had different slopes, and the slope of the nucleus pulposus was significantly greater than that of the anulus fibrosus. Thus, the decrease in water content shortens the T1 in intervertebral discs, and changes in water content have a greater influence on T1 in the nucleus pulposus than in the anulus fibrosus.(ABSTRACT TRUNCATED AT 250 WORDS)

Bilateral open laminoplasty using ceramic laminas for cervical myelopathy.

Evaluation was done of 65 patients with cervical myelopathy treated by bilateral open laminoplasty using artificial laminas, between 1984 and 1988, who had been followed for more than 2 years. The mean recovery rate on the Japanese Orthopaedic Association scoring system was 65% in all cases, and 72% in the cases with no other complications. The artificial laminas appeared well adapted to the laminas in computed tomography and dynamic radiographic examinations, and there were no cases of reduction of the enlarged canal. Postoperative restriction of the range of motion of the cervical spine was lessened by the positioning of lateral grooves, more appropriate external fixation, and posterior flexion exercise after operation. This procedure is not technically complicated, it does not involve appreciable blood loss during operation, it prevents grafted free fat from migrating into the spinal canal, and is advantageous for posterolateral bone chip grafting.

Isolation, structure, and synthesis of novel 4-quinolinone alkaloids from Esenbeckia leiocarpa.

Two new biocidal quinolinone alkaloids, 3-methoxy-1-methyl-2-propyl-4-quinolone [1] and 2(1'-ethylpropyl)-1-methyl-4-quinolone [2], were efficiently isolated using reversed-phase recycling hplc from the leaves of Esenbeckia leiocarpa. The structures were determined through spectroscopic data and confirmed by total synthesis. These alkaloids have antifeedant activities against the pink bollworm, Pectinophora gossypiella.

Selection of bacterial wilt-resistant tomato through tissue culture.

Bacterial wilt-resistant plants were obtained using a tomato tissue culture system. A virulent strain ofPseudomonas solanacearum secreted some toxic substances into the culture medium. Leaf explant-derived callus tissues which were resistant to these toxic substances in the culture filtrate were selectedin vitro and regenerated into plants. These plants expressed bacterial wilt resistance at the early infection stage to suppress or delay the growth of the inoculated bacteria. On the other hand, complete resistance was obtained in self-pollinated progeny of regenerants derived from non-selected callus tissues. These plants showed a high resistance when inoculated with this strain, and were also resistant when planted in a field infested with a different strain of the pathogen.

Multiplication of tobacco mosaic virus in tobacco callus tissues and in vitro selection for viral disease resistance.

Tobacco mosaic virus-resistant tobacco was selected in vitro using callus tissues induced from axillary buds of systemically infected tobacco plants. Callus lines in which the virus was continuously multiplying were first isolated and redifferentiated into shoots. By the procedure, non-diseased, healthy shoots were successfully isolated from diseased shoots, which showed typical mosaic symptoms of the virus, and regenerated into intact plants.These regenerated plants showed resistance to virus inoculation, and selfed progeny of virus-resistant regenerants segregated the resistance and susceptibility according to the Mendelian system.