Assessment of the Correlation between Apparent Diffusion Coefficient and Intervertebral Disk Degeneration Using 3 Tesla MRI.

The objective is to use DW-MR imaging using 3 Tesla MRI to assess the correlation between the mean ADC with degenerative disk disease (DDD). We recruited 34 subjects and used DWI-MR to image lumbar intervertebral disks. We acquired a T2W scan and DWIs. The disks were graded for DDD. Assessment of correlation between mean ADC was made. 170 disks were evaluated. The observed sample correlation between mean ADC and disk degeneration was r = 0.65 [0.55-0.73]. The observed sample correlation between mid-sagittal ADC and disk degeneration was r = 0.61 [0.51-0.70]. The differences between mean ADC of each grade were significant, except between grades 4 and 5. There is a correlation of 0.65 between the mean ADC and disk degeneration. This correlation is not strong enough to use the ADC to determine DDD in clinical settings. There was no evident difference in ADC between the studied anatomic lumbar levels.

Mucous fistula refeeding in neonates with short bowel syndrome.

BACKGROUND/PURPOSE: Neonates with enterostomies commonly suffer from a functional short bowel syndrome (SBS) and have a greater risk of electrolyte and fluid loss with poor weight gain. The authors describe their experience with refeeding stoma effluent into the mucous fistula in neonates. METHODS: A 5-year (1993 to 1997) chart review of neonates with stoma effluent refeeding was undertaken. Demographics, medical history, surgical procedures, timing, and duration of refeedings were reviewed. Enteral and total parenteral nutritional (TPN) requirements, electrolyte, and acid-base disturbances were recorded. RESULTS: Six neonates (gestational ages of 27 to 38 weeks, birth weights of 533 to 3400 g) were identified with nutritional or electrolyte complications before the commencement of refeeding. Enterostomy indications included necrotizing enterocolitis (n = 2), intestinal atresia type 3b (n = 1), complications from ruptured omphalocoele (n = 1), congenital adhesive band obstruction (n = 1), and midgut volvulus after congenital diaphragmatic hernia repair (n = 1). Weight gain during refeeding ranged from 5 to 25 g/kg/d with duration of refeeding lasting 16 to 169 days (two neonates were refed at home) until reanastomoses were done 6 to 44 weeks after the original surgery. There were no complications, and TPN requirements were diminished or eliminated. CONCLUSION: This technique represents a simple and safe method, which lessens the need for TPN and electrolyte supplementation in neonates with enterostomies and SBS before reanastomosis.

Clavulanate induces expression of the Pseudomonas aeruginosa AmpC cephalosporinase at physiologically relevant concentrations and antagonizes the antibacterial activity of ticarcillin.

Although previous studies have indicated that clavulanate may induce AmpC expression in isolates of Pseudomonas aeruginosa, the impact of this inducer activity on the antibacterial activity of ticarcillin at clinically relevant concentrations has not been investigated. Therefore, a study was designed to determine if the inducer activity of clavulanate was associated with in vitro antagonism of ticarcillin at pharmacokinetically relevant concentrations. By the disk approximation methodology, clavulanate induction of AmpC expression was observed with 8 of 10 clinical isolates of P. aeruginosa. Quantitative studies demonstrated a significant induction of AmpC when clavulanate-inducible strains were exposed to the peak concentrations of clavulanate achieved in human serum with the 3.2- and 3.1-g doses of ticarcillin-clavulanate. In studies with three clavulanate-inducible strains in an in vitro pharmacodynamic model, antagonism of the bactericidal effect of ticarcillin was observed in some tests with regimens simulating a 3.1-g dose of ticarcillin-clavulanate and in all tests with regimens simulating a 3.2-g dose of ticarcillin-clavulanate. No antagonism was observed in studies with two clavulanate-noninducible strains. In contrast to clavulanate. No antagonism was observed in studies with two clavulanate-noninducible strains. In contrast to clavulanate, tazobactam failed to induce AmpC expression in any strains, and the pharmacodynamics of piperacillin-tazobactam were somewhat enhanced over those of piperacillin alone against all strains studied. Overall, the data collected from the pharmacodynamic model suggested that induction per se was not always associated with reduced killing but that a certain minimal level of induction by clavulanate was required before antagonism of the antibacterial activity of its companion drug occurred. Nevertheless, since clinically relevant concentrations of clavulanate can antagonize the bactericidal activity of ticarcillin, the combination of ticarcillin-clavulanate should be avoided when selecting an antipseudomonal beta-lactam for the treatment of P. aeruginosa infections, particularly in immunocompromised patients. For piperacillin-tazobactam, induction is not an issue in the context of treating this pathogen.

Treatment of complex postoperative lumbosacral wounds in nonparalyzed patients.

Postoperative infections after back operations can produce complex wounds with myonecrosis, deep dead space, and exposed orthopedic hardware, bone, and dura. Three ambulatory patients with complex postoperative back wounds that resulted from infections were treated successfully with antibiotics, debridement, irrigation, and closure of deep dead space with a superior gluteal muscle flap. Several surgical maneuvers can be performed to increase the length of the superior gluteal muscle flap. The inferior portion of the gluteus maximus was left intact to preserve gluteus maximus function. All three patients obtained healed wounds. The exposed A.O. plating system was not removed. There has not been any recurrence of infections. The superior gluteal muscle flap is a reasonable flap to fill deep dead space in the low back and has some advantages over free flaps.

Cisapride for the treatment of chronic idiopathic constipation.

Cisapride appears to be useful as therapy for chronic constipation that is not associated with underlying organic abnormalities or pregnancy and that is refractory to other treatments, such as increased dietary fiber intake or bulk laxatives. Dosages of cisapride that have demonstrated efficacy in chronic constipation range from 5 mg po tid to 20 mg po bid. Treatment for 8-12 weeks may be necessary for an optimal effect to occur. Further studies are needed to evaluate the most effective dosage regimen for the treatment of constipation and to compare the efficacy and cost-efficiency of cisapride with those of conventional therapy. Until these studies are completed, cisapride should not be recommended routinely for patients with constipation. However, it may be a viable option for patients with chronic idiopathic constipation that is refractory to conventional therapy.

Management of metastatic tumors to the spine using simple plate fixation.

Frequency of metastasis to the spine in the population of patients suffering from malignant disease is a significant clinical problem, as these patients present with intractable pain and neurologic impairment. The sequelae of metastatic tumors to the spinal column significantly decrease the quality of the patient's life. With the advent of modern chemotherapeutic regimens in metastatic disease, patients with metastatic tumors are living longer and more productive lives. The goal of surgical management of this problem is to increase the quality of the patient's life, and not longevity. The immediate technical goals are resection of the pathological segment, restoration of load bearing capacity for mobilization of the patient, and decompression of compromised neural structures, as well as maintenance of spinal stability to decrease pain and increase the patient's quality of life during the terminal stages. This is a series of 28 patients with metastatic tumors to the spine, with an average age of 61.5 years, ranging from 25-81 years of age. Within this population there were 11 different tumor types. The postoperative survivorship was an average of 6.4 months. Twenty patients in this series had an anterior procedure alone using a combination of Methylmethacrylate and inexpensive plate fixation. Six patients required an anterior/posterior procedure for circumferential spinal compression and instability. These techniques provide immediate spinal stability for rapid mobilization of the patient. Twenty-four patients in the series had significant pain relief, and 17 experienced neurologic improvement.(ABSTRACT TRUNCATED AT 250 WORDS)

Neu-Laxova syndrome: pathological evaluation of a fetus and review of the literature.

Neu-Laxova syndrome is a rare autosomal recessive disorder characterized by ichthyosis, intrauterine growth retardation, microcephaly, short neck, central nervous system abnormalities, hypoplastic or atelectatic lungs, limb deformities, edema, polyhydramnios, and short umbilical cord. Abnormal facial features include sloping forehead, hypertelorism, severe ectropion, proptosis, malformed ears, flat nose, and micrognathia. A necropsy study of a male infant with Neu-Laxova syndrome is described. Cleft palate and ambiguous external genitalia were present in addition to anomalies characteristic of Neu-Laxova syndrome. The clinical manifestations are compared with those of the 40 previously reported cases.

The contoured anterior spinal plate system (CASP). Indications, techniques, and results.

The contoured anterior spinal plate (CASP) was developed for secure fixation of the anterior thoracolumbar spine. This is a report of 38 patients with various spinal pathologies treated with this system. The results were excellent regarding plate fixation and fusion. Comments on surgical technique and indications are provided.

Epidural hematomas. An unusual complication of minor blunt force injury due to seizures in a patient with sickle cell disease.

Multiple subacute epidural hematomas in a patient with sickle cell disease (HbSS) are reported. The patient was a 22-year-old Black man with a history of strokes and seizures, who was unexpectedly found dead at his foster home. Scene investigation disclosed no foul play or any indication of violent activities. Autopsy findings included subgaleal contusions and bilateral epidural hematomas, but no calvarial fractures. The epidural hematomas were subacute and closely patterned to the headboard knots of the bed in which the decedent had slept. The etiology of the hematomas is minor blunt force injury secondary to the head striking against the headboard during seizures. The immediate cause of death was determined to be pneumonia and sepsis secondary to HbSS.

A functional in vitro model for studying the cellular and molecular basis of spinal cord injury.

Very little is understood about how spinal cord injury affects the molecular mechanisms responsible for generating locomotion. Recently, it has been shown in the spinal cord that the N-methyl-D-aspartate receptor, a specific class of excitatory amino acid receptors, plays a major role in the neurogenesis of locomotion. Paradoxically, studies of the brain and the spinal cord have shown that overeactivation of this receptor can cause excitotoxicity and subsequent cell death. The ultimate goal of these experiments was to develop an isolated brain stem/spinal cord/hind limb preparation that would allow study of issues related to excitotoxicity and the neurogenesis of locomotion. Findings indicate that: 1) exposure of the spinal cord to the excitatory amino acids produced an alternating gate of the hind limbs; 2) application of N-methyl-D-aspartate inhibitors were effective in preventing hind limb movement initiated by exposure to N-methyl-D-aspartate; 3) sensorimotor stimulation of the tail produced hind limb movement that could be evoked for periods up to 8 hours; and 4) an excitotoxic event produced substantial loss of protein and possible osmotic changes. This study represents the first step in developing a powerful model for examining the effect of spinal cord injury on molecular mechanisms responsible for the neurogenesis of locomotion both at the brain stem, spinal motor generator, or sensorimotor level. The opportunity of observing hind limb movement in this preparation represents a powerful functional bioassay for evaluating the extent of spinal cord injury.

Sudden death in children due to mesenteric defect and mesenteric cyst.

Two cases of sudden death in young female children due to small intestinal volvulus are reported, which involved a mesenteric defect and a mesenteric cyst. Death due to small intestinal volvulus is uncommon, especially when complicated by either a mesenteric defect or cyst.

Postoperative infections in spinal implants. Classification and analysis--a multicenter study.

A multicenter study was undertaken to analyze postoperative wound infections after posterior spinal instrumentation and fusion. The infection rate of these procedures has been documented in multiple reports. From these results, a classification scheme was developed that can guide therapy and determine the populations at risk. The patients were categorized according to two parameters, the first being the severity or type of infection, and the second being the host response or physiologic classification of the patient. This classification scheme is based on the clinical staging system for adult osteomyelitis developed by Cierny. The severity of infection is divided into three groups. Group 1 is a single-organism infection, either superficial or deep. Group 2 is a multiple-organism, deep infection. Group 3 is multiple organisms with myonecrosis. The host response, likewise, is divided into three classes. Class A is a host with normal systemic defenses, metabolic capabilities, and vascularity. Class B patients demonstrate local or multiple systemic diseases, including cigarette smoking. Class C requires an immunocompromised or severely malnourished host. Our data have demonstrated that single organisms, Group 1, generally can be dealt with by single irrigation and debridement, and closure over suction drainage tubes without the use of an inflow-irrigation system. The Group 2 patients, with multiple organisms and deep infection, required an average of three irrigation debridements. They have a higher percentage of successful closures with closed inflow-outflow suction irrigation systems when compared to simple suction drainage systems without constant inflow irrigation. Multiple-organism infections with myonecrosis, Group 3, are exceedingly difficult to manage, and portend a poor outcome. Patients without normal host defenses, Classes B and C, are at high risk for developing postoperative wound infection. Specifically, this study demonstrated that cigarette smoking may be a significant risk factor.

Reconstruction of failed lumbar surgery with narrow AO DCP plates for spinal arthrodesis.

Forty-five patients underwent surgical reconstruction with transpedicular fixation of the lumbar spine with narrow AO DCP plates. Preoperatively, all patients underwent spinal imaging with either magnetic resonance imaging, computed tomography, or myelogram as well as provocative discography to determine the location and the number of symptomatic segments. The minimum follow-up in this series was 2 years. The determination of solid posterior fusion in the presence of plate instrumentation was difficult. The patients in the series were classified as having 1) solid fusion; 2) radiographic flaws within the posterolateral fusion without implant failure; or 3) frank pseudarthrosis with implant failure. Thirty-six (80%) of the patients had a solid fusion, 9 of whom required an additional anterior interbody fusion to obtain symptom control. Twenty percent of the patients in the series had radiographic evidence of reabsorption without implant failure. Four patients in the series (8.8%) had screw breakage, three of which required anterior interbody fusions. The highest rate of reabsorption and pseudarthrosis implant failure was in the 12 patients who had three-level instrumentation; 33% of these patients required anterior interbody fusion to obtain a solid arthrodesis. The average preoperative pain scale was 8.9, and the average postoperative pain scale was a 3.3. Twenty-two patients in the series were cigarette smokers and had a slightly lower fusion rate than non-smokers. They did, however, have a higher use of narcotics after surgery. Forty percent of the patients in this series continued to have radiculopathy after their reconstruction. This study demonstrates the utility of transpedicular fixation in salvage lumbar surgery in obtaining a solid arthrodesis with a beneficial clinical result. Anterior interbody fusions are highly successful in the management of pseudarthrosis and implant failure after transpedicular instrumentation.

Excitotoxins can produce protein degradation in the spinal cord.

Overdistraction and derotation of the scoliotic spine during surgery represent potential complications that could lead to spinal cord dysfunction and paralysis. Neuronal loss and, consequently, the inability to regain function may be attributable to primary damage (eg, mechanical), secondary cell death (eg, such as that produced by ischemia) or a combination of both. Beyond intraoperative recognition and removal of the rods, effective strategies to prevent this neuronal loss have yet to be developed. This emphasizes the need for a clearer understanding of the molecular events that contribute to neuronal injury in the central nervous system. Considerable evidence has indicated that the excitatory transmitter L-glutamate and the N-methyl-D-aspartate (NMDA) excitatory amino acid receptor may contribute to the secondary neuronal death observed in a wide variety of neurological insults, including ischemia. The current investigation was undertaken to elucidate the potential role of the NMDA receptor in spinal cord pathology. Isolated rat spinal cords were exposed to anoxic physiologic solutions in the presence and absence of Ca++, NMDA receptor agonists, and a noncompetitive NMDA receptor antagonist. The extent of neuronal damage was assessed by quantitating the degradation of the cytoskeletal neurofilament protein. A substantial increase in the loss of neurofilament protein was observed in spinal cords exposed to anoxic conditions in the presence of Ca++ as compared with the absence of Ca++. Exposure to excitatory amino acid agonists (L-glutamate or NMDA) further potentiated the degradation of the neurofilament protein; an effect that was reversed by a noncompetitive NMDA receptor antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term lumbar facet joint changes in spinal fracture patients treated with Harrington rods.

Reports in the literature have questioned the practice of using Harrington distraction rods spanning unfused spinal segments for internal fixation of the fractured thoracolumbar spine. However, the long-term incidence of facet joint osteoarthritis has not been reported. This is the report on a retrospective analysis of 20 of these patients with an average follow-up period of 8.0 years. Eighty-five percent of the patients received a classification of good to excellent regarding back pain and 90% returned to their preinjury occupation. Of significance, of 75 lumbar facets traversed by rods but not fused, only two were classified as "closed" or autofused. It remains to be seen if some pedicular systems are superior to this technique in trained hands. However, multisegmental instrumentation with unisegmental fusion is possible without obtaining the severe osteoarthritic changes that animal studies have demonstrated.

A contoured anterior spinal fixation plate.

There is a need for a specifically designed plate for anterior fixation of the vertebral bodies, contoured to fit closely around the lateral aspect of the spine and wide enough to allow multiple options for placement of at least three screws in each vertebra. The large-diameter cancellous screws should penetrate the opposite cortex. Existing bone plates are inadequate, because they are too narrow and do not allow positioning of more than two screws in each vertebra. The Biomedical Engineering Department of the National Research Council of Canada designed and tested the plate described in this article, with particular attention to providing smooth surfaces to prevent vascular complications. Three lengths of plates have been developed and are used in the area from T11 to L5, with a specific tapered plate for the L5 area to prevent contact with the overlying iliac vessels. This device should be used for stabilization following corpectomy for tumor, decompression of burst fractures, severe disc degeneration, pseudarthrosis, and the multiply operated back.

Treatment of tumors of the thoracic and lumbar spinal column.

From December 1981 to February 1986, 33 patients with tumorous conditions of the spine were treated with anterior, posterior, or combined anterior and posterior surgical techniques. Breast metastases were by far the most common condition, accounting for more than 51% of patients with metastatic spinal disease. The surgeon treating tumorous conditions of the spine must be aware that, to date, the treatment is palliative only. The goals of the surgery and treatment are to reduce pain, preserve or improve neurologic function, and allow early mobilization. Survival overall averaged 9.1 months. Of the 14 patients who had anterior decompression alone, average survival time was 9.9 months. The 14 patients who had posterior procedures had an average survival time of 11.9 months. Five patients treated with combined anterior and posterior procedures survived 9.6 months. Fifteen patients with multiple-level spinal involvement survived 7.9 months, compared with 12.9 months for the 18 patients with single-level spinal involvement. Aggressive surgical treatment definitely improves the quality of life of patients with cord compression or unstable spinal segments secondary to bony destruction. An aggressive approach is indicated because it permits most patients to spend the remainder of their lives relatively pain-free and with intact spinal cord function.

The effect of alignment on results in arthroscopic debridement of the degenerative knee.

Fifty-two patients with severe degenerative joint disease of the knees were treated by arthroscopic debridement. The results of arthroscopic debridement on normally aligned degenerative knees are encouraging. A combination of arthroscopic debridement and high tibial osteotomy could be an appealing alternative to total knee arthroplasty in the young patients. Patients with varus angular deformity in the degenerative knee had a poor result and should be excluded from consideration for arthroscopic debridement.