Obesity and litigation predict workers' compensation costs associated with interbody cage lumbar fusion.

BACKGROUND CONTEXT: Results of lumbar fusion surgery have been mixed and procedures are costly. Interbody cage lumbar fusion (ICLF) has been advanced to improve arthrodesis and clinical outcomes; however, little attention has been given to ICLF costs or potential predictors of these expenses. PURPOSE: To depict medical and compensation costs associated with ICLF in a Utah cohort of patients receiving workers' compensation as well as to investigate predictors of costs. STUDY DESIGN/SETTING: A retrospective-cohort research design was used involving completion of presurgical and postsurgical medical record reviews and accrual of medical and compensation costs. Presurgical variables included in a regression model were presurgical spinal pathophysiology rating, obesity, and litigation status. PATIENT SAMPLE: Forty-three consecutive patients who were compensated by the Workers' Compensation Fund of Utah and underwent ICLF. OUTCOME MEASURES: Total accrued compensation and medical costs. METHODS: A retrospective review of presurgical variables and total accrued compensation and medical costs was conducted. RESULTS: Multiple regression analysis indicated that nonpathophysiological factors predicted compensation costs (lawyer involvement [beta=0.40]; obesity [beta=0.34]). Specifically, compensation for those with versus without lawyers was $41,657 versus $24,837, and for those who were obese versus nonobese was $46,152 versus $28,168. Arthrodesis was correlated with medical costs (r=-0.47, p=.002), with incurred costs for patients achieving solid fusion versus pseudarthrosis equaling $38,881 versus $71,655, respectively. CONCLUSIONS: Considerable costs were associated with ICLF, particularly for those who were obese, involved in litigation, or failed to achieve solid fusion. With regard to compensation costs, the findings support the importance of assessing nonpathophysiological factors in spinal fusion patients.     

Reversible reorganisation of the motor cortical representation of the hand in cervical dystonia.

Previous work has suggested that there may be a widespread disturbance of motor control mechanisms in patients with cervical dystonia. In the present study, we used transcranial magnetic stimulation to investigate the topography of the corticomotor projection to the abductor pollicis brevis (APB) muscle in 10 subjects with idiopathic torticollis. Threshold-adjusted stimuli were delivered at multiple scalp sites during a low-level voluntary contraction of the APB, and maps were generated of motor evoked potential amplitude versus scalp site. The cortical maps for the APB on the side opposite to the direction of head rotation were displaced laterally or posteriorly in all subjects and reverted to a more normal position after botulinum toxin injection of the cervical muscles in 5 subjects. The findings point to a reversible reorganisation of the corticomotor representation of the hand on the same side as the sternocleidomastoid (SCM) muscle that is involved in producing the dystonia. These results provide further evidence for the involvement of cortical centres and for a more widespread abnormality of motor control mechanisms in focal dystonia. The findings also support the notion that head turning is chiefly mediated by the hemisphere ipsilateral to the direction of the head rotation by means of a corticomotor projection to the contralateral SCM.     

Vascular injury during anterior lumbar surgery.

BACKGROUND CONTEXT: With the number of anterior lumbar procedures expected to increase significantly over the next few years, it is important for spine surgeons to have a good understanding about the incidence of vascular complications during these operations. PURPOSE: To determine the incidence of vascular injury in 1,315 consecutive cases undergoing anterior lumbar surgery at various levels from L2 to S1. STUDY DESIGN/SETTING: Patients undergoing anterior lumbar surgery were studied. PATIENT SAMPLE: A total of 1,310 consecutive patients undergoing 1,315 anterior lumbar procedures between August 1997 and December 2002 were included in the study. OUTCOME MEASURES: All patients were evaluated for incidence of vascular injury during and immediately after surgery. METHOD: A concurrent database was maintained on all these cases. All the patients had distal pulse evaluation preoperatively. Patients with venous injuries were further analyzed to determine location and extent of injury, amount of blood loss, completion of the procedure and postoperative sequelae. Patients with pulse deficits or evidence of ischemia during or immediately after surgery were further analyzed in particular in relation to demographic, preoperative variables and management. RESULTS: Six patients were identified as having left iliac artery thrombosis (0.45%), and 19 had major vein lacerations (1.4%). CONCLUSION: This study shows that the incidence of vascular injury is relatively low (25 in 1,315 or 1.9%). Because only five of these patients experienced significant sequelae from the approach, it appears that anterior lumbar surgery is quite safe, although it must be carried out with utmost respect for the vessels to avoid possible catastrophic outcomes.     

Intrinsic nerves in the mammalian colon: confirmation of a plexus at the circular muscle-submucosal interface

Slow waves in the small intestine seem to arise in plexuses of neurites with interstitial cells of Cajal. In the colon, slow waves appear to arise at the circular muscle - submucosal interface. We therefore sought a plexus at this surface in the colon in the cat, dog, ferret, opossum, rabbit, rat, guinea-pig and man. Segments from all levels of the colon were stained by the Champy-Maillet osmic acid-zinc iodide method and cut into serial 25 micron sections in the plane of the muscle layers. A dense network of neurites with abundant interstitial cells of Cajal was found at the circular muscle - submucosal interface in all species except rabbit. Neurites in this plexus appeared to arise from the deep plexus of the submucosa (Schabadasch's or Henle's plexus). It was not found in the small intestine and stomach. A similar plexus was found in the interstices of the myenteric plexus in the colon. Interstitial cells of Cajal in both plexuses were positive for the NADH-diaphorase stain, but not for silver impregnation. The possible roles of the plexuses of neurites and interstitial cells of Cajal at the circular muscle - submucosal interface and at the plane of the myenteric plexus in the generation of rhythmic activity in the colon are discussed.     

Corticosteroids for the Enhancement of Fetal Lung Maturity: Impact on the Gravida with Preeclampsia and the HELLP Syndrome

Summary: This study was undertaken to determine maternal impact of corticosteroids administered for the promotion of fetal lung maturity in mothers with the HELLP syndrome. Twenty-seven of 427 women with the HELLP syndrome treated between 1980–1991 received a full course of steroids prior to preterm delivery. This group was compared to 27 matched control patients with the HELLP syndrome who received no corticosteroids. Subjects were matched for maternal age, race, sex of the fetus, and severity of the HELLP syndrome. The antepartum platelet count stabilized or increased in 25 of 27 steroid-treated women in contrast to 0 of 15 control women (p <0.00001). In comparison to control patients, LDH serum concentrations in steroid-treated patients stabilized or decreased and the SGOT/AST and SGPT/ALT stabilized or decreased during therapy (p < 0.005). The interval from delivery to platelet nadir in patients with Class III HELLP syndrome was shorter in the steroid-treated group (p<0.008) than in untreated patients.     

TNFα Inhibits Schwann Cell Proliferation, Connexin46 Expression, and Gap Junctional Communication

Schwann cell responses to nerve injury are stimulated, in part, by inflammatory cytokines. This study compares changes in the phenotype of cultured Schwann cells after exposure to the cytokine tumor necrosis factor (TNF)-α or the mitogen neu differentiation factor (NDF)-β. TNFα inhibited proliferation in a dose-dependent manner without altering Schwann cell survival. TNFα also reduced both gap junctional conductance and Lucifer yellow dye coupling between Schwann cells. Moreover, both P₀and glial fibrillary acidic protein (GFAP) immunoreactivity were reduced. By contrast, NDFβ initially had little effect on cell division although it reduced junctional coupling within 8 h. However, by 48 h, NDFβ stimulated proliferation with a concomitant increase in coupling. Dividing Schwann cells (BrdU⁺) were preferentially dye coupled compared to nondividing cells, indicating an association between proliferation and coupling. Moreover, cultured Schwann cells expressed connexin46 mRNA and protein, and changes in the levels of the protein correlated with the degree of proliferation and coupling. The data thus provide evidence for cytokine-induced modulation of Schwann cell antigenic phenotype, proliferation, and gap junction properties. These observations suggest that enhanced gap junctional communication among Schwann cells after nerve injury could help to coordinate cellular responses to the injury, and that TNFα may be a signal which terminates proliferation as well as junctional communication.     

Influence of glucose ingestion by humans during recovery from exercise on substrate utilisation during subsequent exercise in a warm environment

Carbohydrate (CHO) ingestion during short-term recovery from prolonged running has been shown to increase the capacity for subsequent exercise in a warm environment. The aim of this study was to examine the effects of the amount of glucose given during recovery on substrate storage and utilisation during recovery and subsequent exercise in a warm environment. A group of 11 healthy male volunteers took part in two experiments in a controlled warm environment (35°C, 40% relative humidity), 1 week apart. On each occasion the subjects completed two treadmill runs (T1 and T2) at a speed equivalent to 60% of maximal oxygen uptake, for 90 min, until they were fatigued, or until aural temperature (T _aur) reached 39°C. The two runs were separated by a 4 h recovery period (REC), during which subjects consumed 55 g of naturally enriched [U-¹³C]-glucose in the form of a 7.5% carbohydrate-electrolyte solution (CES, mass of solution 667 g) immediately after T1. The subjects then consumed either: the same quantity of CES, or an equivalent volume of an electrolyte placebo, at 60, 120 and 180 min during REC, providing a total of 220 g (C220) or 55 g (C55) of [U-¹³C]-glucose, respectively. Expired gases were collected at 15 min intervals during exercise and 60 min intervals during REC, for determination of total CHO and fat oxidation by indirect respiratory calorimetry, and orally ingested [U-¹³C]-glucose oxidation, estimated from the ¹³C:¹²C ratio of expired CO₂. Substrate metabolism did not differ between conditions during T1. Despite the fact that total CHO (P<0.05) and ingested glucose oxidation (P<0.01) were greater during REC of the C220 condition, glycogen synthesis was estimated to be approximately fivefold greater (P<0.01) than in the C55 condition. During T2 the rate of total CHO oxidation was higher (P<0.01) and total fat oxidation lower (P<0.01) at all times during the C220 compared to the C55 condition. The greater CHO oxidation during C220 appeared to be met from ingested sources, as the rate of [U-¹³C]-glucose oxidation was greater (P<0.01) at all times during T2, compared to C55. Whilst more of the ingested substrate remained unoxidised on completion of T2 during C220, exercise duration was similar in the two experimental conditions, and was limited by thermoregulatory incapacity (T _aur>39°C) rather than substrate availability per se. Electronic Publication     

Effect of amiloride on electrolyte concentrations and rubidium uptake in principal and mitochondria-rich cells of frog skin

The role of mitochondria-rich cells (MR cells) in transepithelial Na transport was investigated by determining electrolyte concentrations and Rb uptake in individual cells of frog skin epithelium using electron microprobe analysis. Measurements were performed under control conditions and after blocking the transepithelial Na transport with amiloride. Under control conditions, Na and Cl concentrations of MR cells scattered much more than those of principal cells and ranged from a few up to more than 30 mmol/kg wet weight. Rb uptake from the basal side into individual MR cells also showed a large variation and was, on the average, much less pronounced than into the principal cells. In principal cells, amiloride reduced the Na concentration and Rb accumulation. In contrast, no effect was observed upon electrolyte concentration and Rb uptake of MR cells. Rb uptake was correlated to the Na concentration of MR cells both under control conditions and after amiloride. It is concluded that, in contrast to the principal cells, MR cells are not involved in amiloride-sensitive transepithelial Na transport and that their Na/K-pump activity is very low.     

The osmotic behaviour of toad skin epithelium (Bufo viridis)

The effect of saline adaptation on the intracellular Na, K, Cl, P concentrations and dry weight content of the toad skin epithelium (Bufo viridis) was studied using the technique of electron microprobe analysis. The measurements were performed on isolated abdominal skins either directly after dissection or after additional incubation in Ussing-type chambers.Adaptations of the toads to increasing NaCl concentrations for 7 days resulted in increased blood plasma osmolarity and a parallel increase in the cellular electrolyte, P and dry weight concentrations of the epithelium, the K increase representing the most significant fraction of the intracellular osmolarity increase. No evidence was obtained to show that the nucleus and cytoplasm reacted differently from each other and all living epithelial cell types basically showed the same response.Incubation of the isolated skins under control conditions showed a drastic inhibition of the transepithelial Na transport after adaptation to high salinities. In spite of the large variations in the transport rate almost identical intracellular electrolyte concentrations were observed. In tap water adapted toads the average cellular concentrations were 8.8 mmole/kg wet weight for Na, 109.6 for K, 41.5 for Cl, and 135.3 for P, respectively. Incubation of the skin with Ringer's solution of different osmolarities demonstrated that the epithelial cells are in osmotic equilibrium with the inner bathing solution. The results are consistent with the view that the osmotic adaptation is mainly accomplished by the movement of water.This work was supported by grants from the Deutsche Forschungsgemeinschaft and the Stiftung Volkswagenwerk     

LIT1 and H19 methylation defects in isolated hemihyperplasia

We performed LIT1 and H19 methylation studies on 27 children with isolated hemihyperplasia (IH). Eight children (29.6%) had a defect in methylation of one or both of these alleles, supporting our hypothesis that these epigenetic changes can result in a phenotype distinct from typical Beckwith-Wiedemann syndrome.