Current status of adult spinal deformity.

Purpose To review the current literature for the nonoperative and operative treatment for adult spinal deformity. Recent Findings With more than 11 million baby boomers joining the population of over 60 years of age in the United States, the incidence of lumbar deformity is greatly increasing. Recent literature suggests that a lack of evidence exists to support the effectiveness of nonoperative treatment for adult scoliosis. In regards to operative treatment, current literature reports a varying range of improved clinical outcomes, curve correction, and complication rates. The extension of fusion to S1 compared with L5 and lower thoracic levels compared with L1 remains a highly controversial topic among literature. Summary Most adult deformity patients never seek nonoperative or operative treatment. Of the few that seek treatment, many can benefit from nonoperative treatment. However, in selected patients who have failed nonoperative treatment and who are candidates for surgical intervention, the literature reflects positive outcomes related to surgical intervention as compared with nonoperative treatment despite varying associated ranges in morbidity and mortality rates. If nonoperative therapy fails in addressing a patient's complaints, then an appropriate surgical procedure that relieves neural compression, corrects excessive sagittal or coronal imbalance, and results in a solidly fused, pain-free spine is warranted.

Improving the clinical evidence of bone graft substitute technology in lumbar spine surgery.

Bone graft substitutes have been used routinely for spine fusion for decades, yet clinical evidence establishing comparative data remains sparse. With recent scrutiny paid to the outcomes, complications, and costs associated with osteobiologics, a need to improve available data guiding efficacious use exists. We review the currently available clinical literature, studying the outcomes of various biologics in posterolateral lumbar spine fusion, and establish the need for a multicenter, independent osteobiologics registry.

[Bond strength to dentin of resin composites associated with filled and unfilled adhesive systems]. / Resistência de união à dentina de resinas compostas associadas a sistemas adesivos com e sem carga.

This study analyzed in vitro two brands of one-step adhesive systems of fourth generation (Optisolo--Kerr, filled; and Single Bond--3M, unfilled) and two composite resins (Prodigy--Kerr and Z100--3M), aiming at evaluating their bond strength to dentin. Eighty human extracted molars were embedded in acrylic resin and grounded until dentin was exposed in longitudinal direction. The specimens were divided in 4 groups. Composite resin cones were bonded to the specimens using the mentioned adhesive systems, following the instructions of the manufacturers. The test-specimens were submitted to tensile tests using a 4442 Universal Mini-Instron Machine with the speed of 0.5 mm/min. The results were converted into MPa, according to the area of adhesion, and submitted to statistical analysis with ANOVA. There was significant statistical difference (p < 0.01) between the adhesive systems (F = 7.24). Optisolo (m = 11.03 +/- 4.23) showed better bond strength than Single Bond (m = 8.37 +/- 4.54). There was no significant statistical difference (p > 0.05) between the composites (F = 0.43).

Characteristics of pedicle screw loading. Effect of sagittal insertion angle on intrapedicular bending moments.

STUDY DESIGN: A bending analysis of pedicle screws inserted into vertebral body analogues. Intravertebral and intrapedicular pedicle screw bending moments were studied as a function of sagittal insertion angle. OBJECTIVES: To determine how the pedicle screw bending moment is affected by changes in the insertion angle. SUMMARY OF BACKGROUND DATA: There is a significant incidence of failure when pedicle screws are used to instrument unstable spinal segments. Extrinsic factors that affect screw bending failure have been poorly characterized. Previous work has demonstrated that intrapedicular pedicle screw bending moments are significantly affected by the sagittal location and depth of pedicle screw placement. METHODS: Pedicle screw transducers were inserted in analogue vertebrae at one of three orientations: 7 degrees cephalad (toward the superior endplate), 7 degrees caudal (toward the inferior endplate), or parallel to the superior endplate (control). An axial load was applied to the superior endplate of the vertebra, and screw bending moments were recorded directly from the transducers. RESULTS: Screws angled 7 degrees cephalad developed significantly greater mean intrapedicular bending moments compared with screws inserted caudal or control screws. There was no significant difference in bending moments realized within the vertebral body for the three screw positions. CONCLUSIONS: Angulating pedicle screws toward the superior endplate increased bending moments within the pedicle. If attention to optimal screw insertion technique can reduce bending moments and potential for screw failure without increasing morbidity, surgical risk, or operative time, then proper insertion technique takes on new importance.

Influence of inhaled nitric oxide and hyperoxia on Na,K-ATPase expression and lung edema in newborn piglets.

This study was undertaken to examine the combined effect of nitric oxide (NO) and hyperoxia on lung edema and Na,K-ATPase expression. Newborn piglets were exposed to room air (FiO2 = 0.21), room air plus 50 ppm NO, hyperoxia (FiO2 >/= 0.96) or to hyperoxia plus 50 ppm NO for 4-5 days. Animals exposed to NO in room air experienced only a slight decrease in Na,K-ATPase alpha subunit protein level. Hyperoxia, in the absence of NO, induced both the mRNA and the protein level of Na,K-ATP-ase alpha subunit and significantly increased wet lung weight, extravascular lung water, and alveolar permeability. NO in hyperoxia decreased the hyperoxic-mediated induction of Na,K-ATPase alpha subunit mRNA and protein while wet lung weight, extravascular lung water, and alveolar permeability remained elevated. These results suggest that 50 ppm of inhaled NO may not improve hyperoxic-induced lung injury and may interfere with the expression of Na,K-ATPase which constitutes a part of the cellular defense mechanism against oxygen toxicity.

Mitochondrial, but not peroxisomal, beta-oxidation of fatty acids is conserved in coenzyme A-deficient rat liver.

Hepatic coenzyme A (CoA) plays an important role in cellular lipid metabolism. Because mitochondria and peroxisomes represent the two major subcellular sites of lipid metabolism, the present study was designed to investigate the specific impact of hepatic CoA deficiency on peroxisomal as well as mitochondrial beta-oxidation of fatty acids. CoA deficiency (47% decrease in free CoA and 23% decrease in total CoA) was produced by maintaining weanling male Sprague-Dawley rats on a semipurified diet deficient in pantothenic acid (the precursor of CoA) for 5 weeks. Hepatic mitochondrial fatty acid oxidation of short-chain and long-chain fatty acids were not significantly different between control and CoA-deficient rats. Conversely, peroxisomal beta-oxidation was significantly diminished (38% inhibition) in livers of CoA-deficient rats compared to control animals. Peroxisomal beta-oxidation was restored to normal levels when hepatic CoA was replenished. It is postulated that since the role of hepatic mitochondrial beta-oxidation is energy production while peroxisomal beta-oxidation acts mainly as a detoxification system, the mitochondrial pathway of beta-oxidation is spared at the expense of the peroxisomal pathway when liver CoA plummets. The present study may offer an animal model to investigate mechanisms involved in peroxisomal diseases.

Arthroscopic Bankart suture repair for recurrent traumatic unidirectional anterior shoulder dislocations.

We report our experience with arthroscopic repair of the Bankart lesion following traumatic unidirectional anterior shoulder dislocation. Thirty consecutive patients (7 women, 23 men; average age, 26.5 years) were followed for an average of 38 months (minimum 2-year follow-up) after arthroscopic Bankart suture repair for recurrent shoulder dislocation. The study included patients who had pure shoulder dislocations (excluding those with instability secondary to subluxation, multidirectional instability, or an atraumatic origin), had experienced an initial frank shoulder dislocation (documented radiographically or requiring the assistance of medical personnel for reduction), and had a Bankart lesion, visualized arthroscopically. Clinical evaluation using the Rowe functional grading system showed 11 patients rated as excellent, 8 as good, 3 as fair, and 8 as poor. Six of 8 patients were rated as poor because they frankly redislocated following their arthroscopic shoulder stabilization. Our study shows a 27% failure rate in this group. Critical reevaluation of the transglenoid arthroscopic Bankart procedure is mandatory to identify the appropriate patient population for this procedure.

Seizure-induced lumbar burst fracture.

STUDY DESIGN: This case report illustrates how muscle forces generated during generalized seizure activity can result in severe musculoskeletal trauma. A case is presented of a 35-year-old man who suffered seizure-induced contiguous L1 and L2 lumbar burst fractures. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, there have been no reports of seizure-associated lumbar burst fractures. OBJECTIVE: The case is presented to demonstrate how seizure activity can lead to lumbar burst fractures. METHODS: A 35-year-old man suffered a witnessed tonic-clonic seizure while lying on a couch. He had no other trauma and no history of previous seizure activity. As his mental status cleared in the post-ictal period, he complained of mild low back pain. Upon ambulation, he continued to complain of persistent low back pain. Plain radiographs obtained on hospital visit day 5 identified the L1 and L2 contiguous burst fractures. Initial treatment using a Risser cast was unsuccessful, and the patient subsequently underwent posterior spine fusion with Cotrel-Dubousset segmental instrumentation and an iliac crest bone graft. RESULTS: At 1-year follow-up, the patient's spine was stable with no evidence of pseudoarthrosis or further kyphosis. He was maintained on anti-seizure medication. CONCLUSIONS: Forces generated during a tonic-clonic seizure can result in axial skeletal trauma, including thoracic and lumbar burst fractures. Clinical signs of unstable fractures may be subtle. A high index of clinical suspicion is warranted for patients who experience tonic-clonic seizures and who have associated risk factors.

Disruption of mitochondrial energetics and DNA synthesis by the anti-AIDS drug dideoxyinosine.

The purpose of this study was to clarify the role of the mitochondria as a site for the reported hepatotoxic effects of the anti-AIDS drug dideoxyinosine (ddI). Data show that ddI interfered with the mitochondrial redox state in perfused livers leading to more oxidized mitochondria. This effect was reflected by a significant decrease in the mitochondrial NADH/NAD+ ratios from basal values of 0.40 +/- 0.04 to 0.28 +/- 0.02 within 10 min following the infusion of ddI. In suspensions of isolated mitochondria utilizing succinate as a substrate, ddI diminished state 3 and stimulated state 4 respiration significantly, suggesting an uncoupling effect by ddI. Incubation of mitochondria with ddI resulted in a significant decrease in the mitochondrial respiratory control ratios (state 3/state 4 respiration) to 0.8 +/- 0.02 from corresponding control values of 6.0 +/- 0.40 Data also show that ddI inhibited mitochondrial DNA synthesis as evidenced by the decrease in [3H]thymidine incorporation into mitochondrial DNA. This study confirms the need for a close monitoring of patients receiving the dideoxyinosine anti-AIDS drugs and for prompt discontinuation of these drugs before potential irreversible liver damage occurs.