[Spondylolisthesis in the growing spine]

BACKGROUND

Spondylolisthesis (Greek for sliding vertebra) in children is usually the result of a defect (=lysis) or an elongation of the interarticular portion. The cause can be a congenital dysplasia of the dorsal stabilizing structures or pressure of the facet on the interarticular portion. This is a consequence of lumbar lordosis which is necessary for an upright posture.

TREATMENT

The treatment depends on the symptoms and the risk of progression. This is related to the sliding distance, the degree of secondary dysplasia of the vertebral bodies and the sagittal profile, which is considered in the Mac-Thiong classification. For low-grade olistheses, conservative therapy is an option; for a symptomatic lysis without disc degeneration, pars repair should be considered. In higher-grade olistheses, repositioning and spondylodesis are usually recommended. Repositioning improves the fusion rate and sagittal profile, but increases the risk of nerve root damage, so complete repositioning should not be forced.

[Hyaluronic acid gels for pressure regulation in glaucoma treatment]

BACKGROUND

The increasing numbers of glaucoma patients and complications occuring during treatment, such as restenosis and hypotony, require new treatment options to prevent blindness in patients. Therefore, the abovementioned problems should be solved to prolong the lifetime of implants and to prevent repeated surgery.

OBJECTIVE

Can a novel stent with hyaluronic acid hydrogels (HA gel) as a functional unit be used to regulate pressure in glaucoma therapy in the long term?

MATERIAL AND METHODS

Model stents were filled with HA gels and it was investigated if these could regulate the pressure and what the underlying mechanism is.

RESULTS

The results of the investigations showed that the HA gel inside the stent functions as a pressure valve. Under certain equilibrium pressures the HA gel closes the stent and therefore retains the fluid. At a certain overpressure the HA gel enables the fluid to be released and leads to a self-regulated adjustment of the equilibrium pressure.

DISCUSSION

The next step will involve miniaturization of the stents. Experiments will then show if the valve function will also work in the dimensions necessary for an eye implant and if the current problem of hypotension in glaucoma therapy can be solved.

Patient autonomy in multiple sclerosis--possible goals and assessment strategies

Patient autonomy has been increasingly acknowledged as prerequisite for successful medical decision making in Western countries. In medical decisions with a need to involve a health professional, patient autonomy becomes apparent in the extent of patients' participation in the communication as described in the concept of shared decision making. Patient autonomy can be derived from different perspectives or goals and the focus of evaluation approaches may vary accordingly. Multiple sclerosis (MS) is a paradigmatic disease to study patient autonomy mainly because MS patients are highly disease competent and due to ambiguous evidence on many aspects of disease-related medical decision making. This review gives an overview on measurement issues in studying decision making in MS, categorized according to prerequisites, process measures and outcomes of patient autonomy. As relevant prerequisites role preferences, risk attribution, risk tolerance, and risk knowledge are discussed. Regarding processes, we distinguish intra-psychic and interpersonal aspects. Intra-psychic processes are elucidated using the theory of planned behavior, which guided development of a 30-item scale to capture decisions about immunotherapy. Moreover, a theory of uncertainty management has been created resulting in the development of a corresponding measurement concept. Interpersonal processes evolving between physician and patient can be thoroughly analyzed from different perspectives by use of the newly developed comprehensive MAPPIN'SDM inventory. Concerning outcomes, besides health related outcomes, we discuss match of preferred roles during the decision encounters (preference match), decisional conflict as well as an application of the multidimensional measure of informed choice to decisions of MS patients. These approaches provide an overview on patient-inherent and interpersonal factors and processes modulating medical decision making and health behavior in MS and beyond.

Comparison of platelet-rich plasma and VEGF-transfected mesenchymal stem cells on vascularization and bone formation in a critical-size bone defect

Both platelet-rich plasma (PRP) and vascular endothelial growth factor (VEGF) can promote regeneration. The aim of this study was to compare the effects of these two elements on bone formation and vascularization in combination with bone marrow stromal cells (BMSC) in a critical-size bone defect in rabbits. The critical-size defects of the radius were filled with: (1) a calcium-deficient hydroxyapatite (CDHA) scaffold + phVEGF(165)-transfected BMSC (VEGF group), (2) CDHA and PRP, or (3) CDHA, autogenous BMSC, and PRP. As controls served: (4) the CDHA scaffold alone and (5) the CDHA scaffold and autogenous BMSC. The volume of new bone was measured by means of micro-CT scans, and vascularization was assessed in histology after 16 weeks. Bone formation was higher in the PRP + CDHA, BMSC + CDHA, and PRP + BMSC + CDHA groups than in the VEGF group (p < 0.05). VEGF transfection significantly promoted vascularization of the scaffolds in contrast to BMSC and PRP (p < 0.05), but was similar to the result of the CDHA + PRP + BMSC group. The results show that VEGF-transfected BMSC as well as the combination of PRP and BMSC improve vascularization, but bone healing was better with the combination of BMSC and PRP than with VEGF-transfected BMSC. Expression of VEGF in BMSC as a single growth factor does not seem to be as effective for bone formation as expanded BMSC alone or PRP which contains a mixture of growth factors.

Characterization and Fuel Cell Testing of Radiation-Grafted Psi Membranes

We have demonstrated earlier the useful performance of our PSI radiation-grafted membranes in terms of the current-voltage characteristics of 30 cm2 active area fuel cells containing these membranes and their long-term testing over 6,000 h at 60 °C. We report here on testing of PSI radiation-grafted membranes in these fuel cells at 80 °C and in short stacks comprised of two or four 100 cm2 active area cells. The in-situ degradation of membranes has been investigated by characterizing membranes both before testing in fuel cells and post-mortem after testing in fuel cells. Characterization was accomplished by means of ion-exchange capacity and infrared and Raman spectroscopic measurements. In addition, a rapid screening method for our ex-situ testing of the oxidative stability of proton-conducting membranes was developed in this work. Comparison of the initial screening test results concerning the oxidative stability of some perfluorinated, partially-fluorinated, and non-fluorinated membranes compare well qualitatively with the relative stability of these same membranes during their long-term testing in fuel cells.

A Study on Oxidized Glassy Carbon sheets for Bipolar Supercapacitor Electrodes

Electrochemical Double Layer Capacitors (EDLC) for high energy and power density applications, based on glassy carbon (GO) electrodes, are being developed in our laboratory. In the context of this project, GC sheets were oxidized and investigated with Small Angle X-ray Scattering (SAXS), Electrochemical Impedance Spectroscopy (EIS) and Nitrogen Gas Adsorption (BET). During oxidation an active film with open pores is built on the surface of the GC. Upon oxidation, the internal volumetric surface area of the active film decreases, whereas the volumetric electrochemical double layer capacitance increases. We show that this effect is correlated with the opening, the growth and the coalescence of the pores.

[Can failed back surgery be prevented? Psychological risk factors for postoperative pain after back surgery]

Aside from the surgical technique used, the development of peri- and postoperative pain and impairments in patients following intervertebral disk surgery is also determined to a crucial extent by psychological factors. Based on a systematic literature review, we checked whether evidence-based recommendations could be deduced on how to take into account psychological risk factors in back surgery in order to avoid postoperative complications, such as failed back surgery syndrome. The current state of research suggests three groups of risk factors: (1) negative psychological factors, (2) preexisting pain chronification, and (3) psychological disorders. In the case of elective intervertebral disk surgery, these factors should therefore be determined and identified preoperatively and taken into account in the indication for surgery. Multimodal treatments could conceivably prove to be more effective, or else psychological pain management therapy might be considered prior to surgery so as to avoid postoperative complications. If surgery is medically unavoidable despite existing risk factors, postoperative treatment should incorporate psychological pain management therapy at an early stage in the context of a multidisciplinary approach.

[Pain therapy after spinal surgery]

A dorsal approach during spinal surgery offers the possibility to distribute drugs directly to the nerve root or epidurally. This can be done via a single intraoperative dose or by placing an epidural catheter. A safe and effective analgesia can thereby be achieved. As placement is done under visual control, no major complications are to be expected. In nerve root compressions, additional local application of steroids and preoperative gabapentin seems sensible. No advantage of preemptive administration of other analgesics can be determined. Another problem, especially of ventral fusions, is the commonly needed autologous pelvic bone grafts. Here the local application of local anesthetics or opioids makes sense. In transthoracic approaches epidural analgesia is recommended by thoracic surgeons, but this is difficult to perform especially in children with deformities. Furthermore it is generally important not to compromise neuralgic controls by analgesic measures.

[Pain and its treatment reflected in time]

This article describes the history of pain therapy and anesthesiology with respect to the field of surgery. The history of this part of medicine is dependent upon the development of the appropriate medication groups, which were of great importance in the field of pain therapy and anesthesiology. Specifically the development of nitrous oxide, ether, morphine and the first local anesthesiologic substances will be described and discussed. The above mentioned developments combined with the knowledge of physiology of pain and new results from psychological studies led to the modern pain therapy in recent perioperative treatment concepts. Modern pain therapy is a multimodal therapy concept with a variety of specialties working as a team to optimize an individualized therapy plan which respects the needs of every single patient under different circumstances (acute, perioperative and chronic pain).

[Special features of procedures in paediatric orthopaedics]

To get good to excellent results in paediatric orthopaedics perioperative pain treatment is essential. Guidelines are in general similar to those for adults. Some special features should be taken into account. Differences are reduced possibilities of communication in the early years, different pharmacokinetics and a different perception of pain itself. A multimodal approach has proven to be very effective: workflow tailored to children's needs, ambiance appropriate for children and pharmacological analgesia. Children and parents have to be informed carefully about procedures, hospital setting and pain therapy in the first session. Pain therapy is orientated to the reversed WHO pain treatment scheme completed by surface and regional anaesthesia. After discharge pain treatment has to be administered. This article presents concepts of perioperative analgesia.

Follow-up of 11-16 years after modular fixed-bearing TKA

To present representative data of long-term survivorship and clinical outcome for the PFC total knee arthroplasty (PFC-TKA). A consecutive series of 141 TKA was followed for a mean of 13 years (range, 11-16 years). Sixty-five knees were evaluated, 30 of these clinically and radiographically. Twenty-eight knees could only be assessed with the use of a questionnaire. Six patients were living in nursing homes. Fifty-four patients (65 knees) had died. Eleven had undergone a revision. One patient was considered lost to follow-up. With re-operation for any reason as the endpoint, the 10-year survival rate was 92% (n = 91 patients at risk), and the 14-year survival rate was 91% (n = 12). With aseptic loosening of the implant as the endpoint, the 10- and 14-year survival rates were 97%. The mean Knee Society and function scores were 76 and 48 points, respectively. In this multi-surgeon series modular fixed-bearing TKA had good clinical and radiographic results with excellent long-term survivorship.

VEGF producing bone marrow stromal cells (BMSC) enhance vascularization and resorption of a natural coral bone substitute

Bone graft substitutes often exhibit poor bone regeneration in large defects because of inadequate vascularization. Studies have shown that if blood supply is compromised, application of osteogenic factors alone could not induce successful healing. This study was to evaluate the effects of vascular endothelial growth factor, which combined with a coralline scaffold, on vascularization, scaffold resorption and osteogenesis in a rabbit radius critical size defect model. The scaffold was either coated with a control-plasmid DNA (group 1), coated with VEGF-plasmid DNA (group 2), loaded with mesenchymal stem cells (BMSC) transfected with control plasmid (group 3) or with both stem cells and the VEGF plasmid (group 4). X-rays were taken every 4 weeks up to week 16, when animals were euthanized. The volume of new bone was measured by mu-CT scans and blood vessels were counted after anti-CD31 staining of endothelial cells. The results from the solitary VEGF- and VEGF-transfected cells (groups 2 and 4) demonstrated significantly enhanced vascularization, osteogenesis and resorption of the carrier when compared to the control group. The highest degree of osteogenesis was found when the carrier was loaded with BMSC (group 3), whereas VEGF-transfected cells led to the highest vascularization and fastest resorption of the bone substitute. Additionally, VEGF-transfected BMSC led to a more homogenous vascularization of the defect. The results indicate that VEGF can be a helpful factor to improve healing in large bone defects, in which bone substitutes will otherwise not be vascularized and replaced by fresh bone.

Compliance with continuous passive movement is low after surgical treatment of idiopathic club foot in infants

Treatment by continuous passive movement at home is an alternative to immobilisation in a cast after surgery for club foot. Compliance with the recommended treatment, of at least four hours daily, is unknown. The duration of treatment was measured in 24 of 27 consecutive children with a mean age of 24 months (5 to 75) following posteromedial release for idiopathic club foot. Only 21% (5) of the children used the continuous passive movement machine as recommended. The mean duration of treatment at home each day was 126 minutes (11 to 496). The mean range of movement for plantar flexion improved from 15.2° (10.0° to 20.6°) to 18.7° (10.0° to 33.0°) and for dorsiflexion from 12.3° (7.4° to 19.4°) to 18.9° (10.0° to 24.1°) (both, p = 0.0001) when the first third of therapy was compared with the last third.

A low level of patient compliance must be considered when the outcome after treatment at home is interpreted.

[Proximal fracture of the femur in elderly patients. The influence of surgical care and patient characteristics on post-operative mortality]

In a retrospective study, 1.173 fractures of the proximal femur, which had been treated surgically, were analysed in two periods from 1975 to 1991 and from 1992 to 2000. The influence on mortality of preoperative risk factors and primary treatment with total hip replacement (THR), even in cases of pertrochanteric fractures, was analysed by stepwise logistic regression. In the later period, mortality within 90 days was 13.1%, and within 1 year 22.2%. Rejection of hemiendoprosthesis in high-risk patients with intracapsular fractures increased the mortality rate from 6.3% to 11.8%. The introduction of dynamic hip screws instead of Ender nails led to a reduction of mortality from 16.5 to 7.1%. Higher mortality after THR (27.6%) compared to osteosynthesis (15.5%) in pertrochanteric femur and lateral neck fractures was due to higher age and increased risk factors. Although the influence of some risk factors could be reduced, age, sex and morbidity influenced the outcome more than surgical treatment. THP, even after pertrochanteric fractures, is reasonable if it guarantees a quick and enduring mobilisation of the patient. Bicentric bipolar prostheses are recommended for high risk patients.

Tibiakopfumstellung mittels Fixateur externe

External fixation is a proved method for high tibial osteotomies. It is easy to access, allows postoperative corrections of the alignment, and can be removed without additional narcosis. Disadvantages are the frequent infection of the pin tracks and discomfort in bearing compared to internal fixation. In our own study no difference between unilateral and bilateral fixation could be found regarding loss of correction and complications. The advantage of unilateral fixation is the possibility of doing an open-wedge procedure by unilateral continuous callus distraction (hemicallotasis). This is indicated if medial collateral instability can be compensated by the open-wedge technique. The occurrence of neural injuries was significantly less frequent after hemicallotasis. Regular radiological and clinical control of the axis is necessary to prevent loss of correction, which was significantly more frequent in open-wedge osteotomies.

Surgical management of paralytic scoliosis in myelomeningocele

A retrospective analysis of 54 patients with paralytic scoliosis due to myelomeningocele, who underwent surgical treatment, was performed. The aim of this study was to compare different surgical techniques and to identify clinical parameters influencing primary and midterm results. Three surgical techniques were used: 1) group I, posterior fusion/instrumentation; 2) group II, anterior fusion/no instrumentation combined with posterior fusion/instrumentation; and 3) group III, anterior and posterior fusion/instrumentation. Average age at surgery was 13.1 years. A preoperative scoliosis angle of 90 degrees [interquartile range (25th-75th percentile) (IQR), 76-106 degrees] was primarily reduced to 38 degrees (IQR, 30-50 degrees). At final follow-up (mean, 3.3 years), correction deteriorated to 44 degrees (IQR, 38-65 degrees). The group III procedure resulted in a better midterm correction of scoliosis compared with group I (P = 0.02). The extension of anterior fusion correlated with primary and midterm correction of scoliosis (P < 0.03). Patients with a thoracic level of paralysis had a higher relative loss of correction compared with patients with a lumbar level (P < 0.06). This finding can be attributed mostly to group I patients (P = 0.011). Hardware complications occurred in 16 patients (30%). Relative loss of correction among these patients was high (P < 0.01) and relative midterm correction low (P = 0.001). We recommend anterior and posterior fusion, each with instrumentation for the treatment of paralytic scoliosis in myelomeningocele. In patients with a thoracic level of paralysis, the two-stage procedure is mandatory to reduce the risk of hardware complications and subsequent major loss of correction.

External fixation in proximal tibial osteotomy: a comparison of three methods

During a period of 6 years (1990-1996), 154 patients with unilateral gonarthrosis underwent proximal tibial osteotomy using 3 different methods of external fixation: (1) closing wedge osteotomy and bilateral fixation; (2) closing wedge osteotomy with unilateral fixation, and (3) opening wedge osteotomy with unilateral fixation. The most common complications were pin-tract infection (25%), temporary nerve palsy (10%), and loss of alignment (17%). At least one complication developed in 33% of patients in this study, indicating that the use and technique of external fixation in proximal tibial osteotomy can be problematic.

Complications of scoliosis surgery in children with myelomeningocele

The purpose of the present study was to evaluate whether the high incidence of complications in scoliosis surgery in myelomeningocele (MMC) could be attributed to the surgical technique and whether improvements were possible. Between 1984 and 1996, 77 patients with MMC and scoliosis were treated surgically. The clinical and radiological follow-up ranged from 1 to 10 years with a mean follow-up of 3.6 years. The mean age at time of surgery was 12 years 8 months. The average preoperative scoliosis measured 90.20 degrees and was corrected by 47%. The first four patients were stabilized with Harrington rods after anterior correction with a Zielke device (group 1). Twenty-five patients were operated only from posterior, using Cotrel-Dubousset (CD) instrumentation (group 2). In 13 patients an anterior release and discectomy was performed prior to CD posterior instrumentation (group 3). In 26 patients (group 4) this was combined with an anterior instrumentation. The 9 patients of group 5 had congenital vertebral malformations which made a special treatment necessary. Complications could be divided into hardware problems, such as implant failure, dislocation or pseudarthrosis, infections, anesthetic, and neurologic complications. Hardware problems were seen in 29% of all patients. More hardware problems were seen with the Harrington rod (75%) and after solitary posterior instrumentation (30%). The occurrence of pseudarthrosis was dependent on the surgical technique, the extent of posterior spondylodesis, and lumbosacral fusion. Patients with hardware problems had a mean loss of correction of 49% compared to 13% in the other patients. Depending on the different surgical techniques a loss of more than 30% was seen in 12-75% of the cases. Early postoperative shunt failure occurred in four cases; delayed failure - after more than 1 year - in three cases. One patient died within 1 day due to an acute hydrocephalus, another died after 2 1/2 years because of chronic shunt insufficiency with herniation. Wound problems were not dependent on the surgical technique, but on the extent of posterior spondylodesis and the lumbosacral fusion. Based on this analysis we believe our current practice of instrumented anterior and posterior fusion is justified. Further, we are very careful to check shunt function prior to acute correction of spinal deformity.

Glucocorticoids regulate the expression of the human osteoblastic endothelin A receptor gene

The endothelial cell-derived peptide endothelin 1 (ET1) stimulates cell proliferation and differentiated functions of human osteoblastic cells (HOC), and HOC constitutively express the endothelin A receptor (ETRA). Therefore, ET1 may play an important role in the regulation of bone cell metabolism. As glucocorticoids (GC) exert a profound influence on bone metabolism and increase the effects of ET1 on bone cell metabolism in vitro, the effects of GC on ETRA expression in HOC were investigated. Dexamethasone (DEX) increased ETRA mRNA levels in a dose- and time-dependent fashion. The effects of dexamethasone, prednisolone, and deflazacort on the increase of ETRA mRNA levels correlate positively with their binding affinity to the GC receptor. Scatchard analysis of ET1 binding data to HOC revealed that DEX increased the binding capacity for ET1 from 25,300 to 62,800 binding sites per osteoblastic cell, leading to an enhanced mitogenic effect of ET1 on HOC after preincubation with DEX. Transiently transfected primary HOC with a reporter gene construct, containing the 5'-flanking region of the ETRA gene fused to luciferase gene, showed a promoter-dependent expression of the reporter gene and the induction of reporter gene expression by DEX treatment. Total RNA extracts of femoral head biopsies with osteonecrotic lesions from GC-treated patients showed threefold higher ETRA mRNA levels compared with extracts of bone biopsies from patients with traumatically induced osteonecrosis and coxarthrosis. Furthermore, GC treatment increased plasma ET1 levels by 50% compared with pretreatment values. These findings suggest that GC induced upregulation of ETRA, and ET1 plasma levels enhance ET1's anabolic action on bone cell metabolism. Increased ET1 concentrations may also impair bone perfusion by vasoconstriction in a metabolically activated skeletal region.

[IODIDA scanning for functional and morphologic assessment of the liver and bile ducts before and following surgical interventions in bile duct obstruction]

PROBLEM

Full pre- and postoperative assessment is mandatory in the management of complex cases of incomplete biliary obstruction. Investigations should not only define the level of extrahepatic bile duct obstruction but also detect intrahepatic obstruction, give some index of liver function and of the dynamics of biliary flow. Computed tomography, ultrasonography and direct cholangiography are very valuable. IODIDA-scanning provides a non-invasive method which not only complements other studies but also gives information otherwise unobtainable.

CLINICAL MATERIAL

In an initial retrospective study 36 patients, 12 of whom had previously undergone operation for biliary obstruction, were fully investigated with particular reference to the use of IODIDA-scanning.

PROCEDURE

2-5 mCi of 99mTc labelled IODIDA were injected intravenously and the liver and upper abdomen scanned at 1 minute intervals and displayed at 5 minute intervals during the first hour.

RESULTS

All patients were studied on admission and then postoperatively at intervals. In 31 of 36 patients IODIDA-scanning gave reliable evidence of the level of obstruction of biliary flow and of the patency of biliodigestive anastomosis. Assessment of liver function before and after biliary reconstruction was also possible.

CONCLUSION

IODIDA-scanning has proved a valuable non-invasive method for the assessment of liver parenchymal function, intrahepatic abnormalities and of bile flow in cases of complex biliary obstruction. This is particularly valuable with the Roux-Y biliary reconstruction since ERCP is impossible and PTC an invasive method which, although supplying an accurate picture of major biliary obstruction, fails to characterize hepatic function and bile flow.

Developing and negotiating transfer agreements in allied health

The Kentucky Council on Higher Education has developed a statewide articulated system for allied health education. The articulated system permits entry and exit of prepared professionals at a variety of levels. The six disciplinary clusters included in the system are clinical laboratory sciences, dental auxiliaries, dietetics/nutrition, rehabilitation therapies, radiological sciences, and respiratory therapy. Competency-based education was used as the theoretical framework for developing and negotiating transfer agreements. Types of agreements included the block credit transfer agreement and the course specific transfer agreement. Agreements were negotiated between education systems and between specific programs/institutions. To date, approximately 30 transfer agreements have been negotiated. The process for negotiating transfer agreements included the following sequence: identify programs, develop a theoretical articulation model, rank order transfer agreements, determine the type of agreement, review respective curricula, determine the existing amount of transferable coursework, draft a pre-articulation agreement, schedule a meeting between faculty and administrators to discuss the agreement, and secure authorizing signatures on the final transfer agreement. Facilitators and barriers to negotiating agreements are discussed and recommendations offered for others who may be interested in developing transfer agreements.

Lymphocutaneous nocardia Brasiliensis infection simulating sporotrichosis

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Teaching of general practice

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