Generalised cranial artery spasm in human rabies.

In 2004, a teenager survived bat-associated rabies through the Milwaukee protocol (MP). This survivor and another patient with dog-associated rabies were found to have developed deficiencies of tetrahydrobiopterin (BH4) and associated neurotransmitters. BH4 is also essential for neuronal nitric oxide synthase (nNOS), so rabies is predicted to cause constriction of cerebral arteries. We assume that rabies virus, which almost exclusively targets neurons, would disproportionately affect cerebral over systemic perfusion by disrupting nNOS and lead to generalised cerebral artery spasm. Cranial artery vasospasm, therefore, was actively sought in two rabies patients, with the intention to specifically treat with BH4 and L-arginine when necessary. Flow velocities and resistive (RI) or pulsatility indices (PI) of middle cerebral arteries (MCA) were obtained by transcranial doppler ultrasound (TCD). A survival analysis of 8 attempts at the MP is presented. Of these, two cases are reported here. The first case is one child with bat-associated rabies who developed severe bilateral MCAspasm on hospital day (HD)-10 that responded to very low dose (0.2 mcg/kg/min) nitroprusside. The second case, a child with dog-associated rabies, developed spasm of MCA on HD-6 that responded to 6 mg/kg/day BH4. A second spasm with high RI (without cerebral oedema or increased intracranial pressure) responded to 20 mg/kg/day BH4 and 0.5 g/kg/dose L-arginine. Review of the TCD of the first child showed a similar second spasm seven days after first episode. Cerebral artery vasospasm occurred in the two children with rabies, but was clinically silent by standard monitoring. Spasm responded to drugs directed at the NOS pathway. Animal models for treatment of rabies are sorely needed to evaluate therapy.

Health-related quality of life measured by the UW-QoL--reference values from a general dental practice.

The objective of this study was to obtain age and sex-specific reference values for the University of Washington head and neck cancer questionnaire version 4 (UW-QoLv4) and to compare this with patients with oral and oropharyngeal cancer. Cross-sectional reference data was collected from 372 patients in six local general dental practices, 349 of whom presented for routine appointments. Quota sampling was used to collect data for similar numbers of patients by gender by four age bands (40-49, 50-59, 60-69, 70-79 yr). The longitudinal sample consisted of 450 consecutive patients undergoing primary surgery for previously untreated oral and oropharyngeal squamous cell carcinoma presenting to the Regional Maxillofacial Unit Liverpool, between the years 1995 and 2002. At baseline the key differences were anxiety, pain, swallowing, chewing, and mood. At 1yr there were big differences in all domains with deterioration in the oral cancer group. The difference was least notable in pain, shoulder, mood and anxiety. Reference data from a non-cancer population is very important when considering UW-QoL domains as an outcome parameter in clinical trials and also when discussing health-related quality of life outcomes with patients and their families.

Biomechanics of the first ray. Part III. Consequences of Lapidus arthrodesis on peroneus longus function: a three-dimensional kinematic analysis in a cadaver model.

It has long been proposed that first metatarsocuneiform joint (FMCJ) arthrodesis, also known as Lapidus arthrodesis, can realign the first ray and permanently lock the FMCJ to control hypermobility. Left unanswered is the functional consequence of peroneus longus (PL) after such a procedure. In this study, the effects of PL on the medial column of the foot before and after metatarsocuneiform arthrodesis were evaluated. Seven fresh-frozen cadaver specimens with an intact foot and ankle were mounted on a custom-made acrylic frame and loaded to 400 N while midstance motor function was simulated with pneumatic actuators. Three-dimensional radiowave tracking transducers were attached to the first metatarsal, medial cuneiform, navicular, and talus to measure osseous movements while tensile loads of 0% to 100% of PL predicted force was applied. Simulated arthrodesis of the metatarsocuneiform joint and then additionally the intercuneiform 1-2 joint was achieved with titanium pins and then retested to determine any change in effect from PL. Significant frontal plane eversion of the medial cuneiform (p = .016) and dorsiflexion of the talus (p = .045) occurred after Lapidus arthrodesis was achieved. This suggests that arthrodesis at the first metatarsocuneiform joint increases the efficiency of PL stabilizing action on the medial column.

Biomechanics of the first ray. Part II: Metatarsus primus varus as a cause of hypermobility. A three-dimensional kinematic analysis in a cadaver model.

Variation in functional stability of the first metatarsocuneiform joint was analyzed between transverse plane deviated (adducted) and corrected first metatarsal positions in a closed kinetic chain model. Six fresh frozen cadaver specimens with intact ankles and feet were fitted with a custom fabricated titanium metatarsal jig, which allowed for manipulation of the first metatarsal in the transverse plane. Specimens were mounted into a custom-made acrylic load frame and axially loaded to 400 N. Radiowave three-dimensional tracking transducers were attached to the following osseous segments: first metatarsal head and base, medial cuneiform, and second metatarsal. A dorsally directed load was applied to the first metatarsal segment and resultant movements were measured. Repeated testing was performed on a transverse deviated and corrected first metatarsal positions with the hallux plantargrade and maximally dorsiflexed to engage the windlass mechanism. With the windlass mechanism engaged and first metatarsal corrected, a 26% increase in first ray plantarflexion occurred from a deviated to a corrected first metatarsal position (p < or = .05). This suggests that the windlass mechanism is more efficient when the first metatarsal, sesamoid apparatus, and hallux position are properly aligned with the orientation of the plantar aponeurosis. Clinically, this may explain the correlation of first ray hypermobility with the progression of bunion severity. Our study validates the earlier work of Hicks and adds additional insight into the functional stability in the medial column of the foot.

gamma-Aminobutyric acid infusion in substantia nigra pars reticulata in rats inhibits ascorbate release in ipsilateral striatum.

A relatively high level of extracellular ascorbate in the striatum, which is known to modulate impulse flow in striatal neurons, originates primarily from glutamate-containing corticostriatal afferents. Increasing evidence suggests that ascorbate release from these fibers is regulated by a multisynaptic loop that includes gamma-aminobutyric acid (GABA) mechanisms in the substantia nigra. To assess the role that nigral GABA plays in striatal ascorbate release, extracellular ascorbate was monitored voltammetrically in the striatum during infusions of GABA into the substantia nigra pars reticulata (SNr) of awake, unrestrained rats. Compared to vehicle infusions, intranigral GABA lowered striatal ascorbate by >50%. In contrast, intranigral application of picrotoxin, a GABA antagonist, had the opposite effect. Neither GABA nor picrotoxin altered striatal 3,4-dihydroxyphenylacetic acid (DOPAC), a major dopamine metabolite. Collectively, these results indicate that intranigral GABA exerts a tonic inhibitory influence on ascorbate release in the striatum.

Biomechanics of the first ray. Part I. The effects of peroneus longus function: a three-dimensional kinematic study on a cadaver model.

The closed kinetic chain effects of peroneus longus (PL) activity on the medial column of the foot were investigated in seven fresh-frozen cadaver specimens using a three-dimensional radiowave tracking system. Specimens, consisting of the distal half of the leg and the intact ankle and foot, were mounted on a nonmetallic loading frame which allowed positioning of the foot to simulate midstance position of gait. The tibia and fibula were axially loaded to 400 N. Receiving transducers were attached to the first metatarsal, medial cuneiform, navicular, and talus. Tarsal movements were measured as specimens were axially loaded and midstance motor function was simulated using pneumatic actuators. Tensile loads of 0-150% of predicted maximum force were incrementally applied to the PL tendon. Three-dimensional data sets recording osseous positions and orientations were collected and analyzed. Significant frontal plane rotation of the medial column in the direction of eversion occurred when PL strength was increased (p = .0001). Increasing PL loads produced significant but less pronounced angular changes in the sagittal and transverse planes of the medial column. The patterns of motion suggest that PL creates an eversion "locking" effect on the first ray of the foot, stabilizing the medial column.

Integrating the terminology and titles of nursing practice roles: quality, particularity and levelling.

In this paper, written following the recent workshop on advanced practice, the author takes a fresh look at the meaning of expert, specialist and advanced practice. She proposes that they are distinctive and complementary aspects of every nursing role, and suggests a set of attributes for each.

Biomechanical analysis of the first metatarsocuneiform arthrodesis.

This investigation was designed to help define the unique loading characteristics of the first metatarsocuneiform arthrodesis procedure. Part I of this investigation employed nine fresh frozen, matched-pair cadaveric specimens. One specimen in each pair had the subchondral plate removed from the opposing joint surfaces, while the remaining specimen had only the articular cartilage removed. All specimens were stabilized in an identical manner utilizing two 3.5-mm cortical screws. Part II of the investigation also utilized nine fresh frozen, matched-pair cadaveric specimens. Only the articular cartilage was removed prior to placement of fixation. All specimens were stabilized with two crossing 3.5-mm cortical screws. Placement of a third screw was randomized between specimens of a matched pair. Specimens were loaded to failure in cantilever bending utilizing a materials tester. There was a statistically significant (p = .04) greater load to failure and bending moment in specimens with an intact subchondral plate. Values for construct stiffness were not found to be significantly different (p = .95) between specimens with and without a subchondral plate. Although the addition of a third screw increased the load to failure and bending moments, differences were not found to be statistically different (p = .11-.21) from two screws. Preserving the subchondral plate will enhance the stability of the first metatarsocuneiform arthrodesis. Two or three screws can be employed to shield the fusion site from loading; however, three screws were shown to be more effective than two.

Stabilization of the subluxed second metatarsophalangeal joint: flexor tendon transfer versus primary repair of the plantar plate.

Surgical treatment of the subluxed second metatarsophalangeal joint (MTPJ) has been a consistently frustrating problem for the foot and ankle surgeon. The plantar plate is the principal stabilizing structure of the second MTPJ and compromise to its integrity has been implicated as the cause of the subluxed second toe. Flexor tendon transfer has been reported as the mainstay of treatment to stabilize the subluxed second MTPJ. Recently, primary repair of the plantar plate has been advocated, yet no research exists comparing it to flexor tendon transfer. Eight freshly frozen lower extremity cadaver specimens were mounted on a custom-fabricated load frame. A vertical dorsally directed force was applied to the base of the proximal phalanx of the second toe via a pneumatic actuator to stimulate the Lachman test. Dorsal displacements of the proximal phalanx were measured with a linear variable distance transducer. This investigation examined the comparative strength of flexor tendon transfer versus primary repair of the plantar plate in stabilizing the second MTPJ. Results showed a significant difference between the transected plantar plate and the intact plantar plate. Displacements for the repair groups were similar to the intact plantar plate group and also significantly different from the transected plantar plate. Primary repair of the plantar plate is a viable alternative to flexor tendon transfer in stabilizing the second MTPJ with the advantage of addressing the pathology anatomically. Clinical studies are needed to substantiate these laboratory findings.

Critical evaluation of anterior drawer measurement methods in the ankle.

Anterior drawer testing has been used to assess the integrity of the lateral collateral ligaments, most notably the anterior talofibular ligament. Various radiographic measurement methods have been designed to assess sagittal plane talar displacement under stress. This investigation examined the anterior drawer test in 8 fresh frozen lower extremity cadaver specimens. Each specimen was mounted on a fabricated test frame and instrumented with a linear variable displacement transducer to directly measure talar displacement during stress application. Lateral radiographs were taken before and during stress application. Two radiographic measurement techniques (concentric circle and plafond to dome), each corrected for magnification effect, were compared with directly measured talar displacement values with the foot placed in 20 degrees plantar flexion. There were no significant differences between talar displacements measured directly and radiographically using the concentric circle method. Significant differences were found between directly and radiographically measured displacements using the uncorrected plafond to dome method. Subtracting the unstressed from the stressed tibiotalar distance for the plafond to dome method resulted in no significant difference from directly measured talar displacement values. It is not necessary to correct talar displacement values obtained when using the concentric circle method.

Closed kinetic chain tarsal mechanics of subtalar joint arthroereisis.

The weightbearing biomechanics of the tarsus with and without subtalar joint arthroereisis was investigated in 11 fresh frozen cadaver specimens using a three-dimensional (3-D) radiowave tracking system. Specimens, consisting of the distal half of the tibia and fibula and the intact ankle and foot, were mounted on a nonmetallic loading frame test system that allowed positioning of the foot to simulate midstance position of gait. The tibia was axially loaded to 756 N (one bodyweight) with 15% of the total load diverted through the fibula. Receiving transducers were attached to the talus, navicular, calcaneus, and cuboid bones. Tarsal movements were monitored as the specimen was loaded with and without subtalar joint arthroereisis. Three-dimensional data sets of osseous positions and orientations were collected and analyzed. Significant rotational differences were detected with and without subtalar joint arthroereisis for all four tarsal bones (p < or = 0.05). Tarsal translational position changes were small and not statistically significant.

Stiffness of screw fixation and role of cortical hinge in the first metatarsal base osteotomy.

The authors investigated various factors that affect stiffness of screw fixation in the oblique first metatarsal osteotomy. One screw versus two screw fixation with intact medial cortical hinge, and two screw fixation without hinge were tested on the same metatarsal specimen. Mechanical properties of the fixation patterns were measured on a materials testing apparatus. Each metatarsal was tested at below failure threshold for stiffness within the elastic range of the specimen. Load versus displacement curves and fixation stiffness values were generated for axial loading, valgus torque, and plantar-to-dorsal cantilever bending. Osteotomies with an intact hinge demonstrated superior stiffness in most parameters as compared to osteotomies without a hinge. Two screw fixation with intact hinge showed significantly increased axial stiffness as compared to one screw fixation. There was no statistical difference between one and two screws in cantilever bending and torsional stiffness with an intact hinge. The major stabilizing factor of the first metatarsal base osteotomy is the medial cortical hinge.

Unilobed and bilobed skin flaps. Detailed surgical technique for plantar lesions.

The authors provide a detailed description of effective surgical techniques for painful plantar skin lesions of the foot that are not amenable to simple excisional procedures. Modified unilobed and bilobed skin flaps are described, emphasizing step-by-step design and procedure performance. These advanced techniques offer numerous advantages over other excisional and flap methods, such as being reproducible and yielding predictable results.

1994 William J. Stickel Gold Award. Contact characteristics of the ankle joint. Part 2. The effects of talar dome cartilage defects.

Variations in ankle joint contact characteristics caused by articular defects of the talar dome were investigated in 14 fresh-frozen cadaver specimens using pressure-sensitive film. Intact ankle and foot specimens were mounted in a materials tester on a loading frame which allowed positioning in neutral, and 20 degrees of dorsiflexion and plantarflexion. Joint contact prints were recorded while an 800 N load was axially applied through the leg. Specimens were randomly placed into two lesion groups: either anterolateral or posteromedial. During testing, each specimen had four concentrically placed lesions on the talar dome, graduated in size. Following removal, the film transducers were digitized along with pressure calibration prints. The images were analyzed quantitatively to determine contact areas, mean contact pressures, ratio of to contact plafond areas, and high pressure centroid position as a function of lesion size and location. The results demonstrated significant changes in contact characteristics for larger lesions (> or = 7.5 x 15 mm) (P < 0.05). These findings suggest that determining the size of a lesion may assist in predicting the long-term outcome of ankles with cartilage defects.

Contact characteristics of the ankle joint. Part 1. The normal joint.

The contact characteristics of ankle joints in 18 fresh cadaver specimens were studied by using pressure-sensitive film to provide baseline information for subsequent studies of various pathologic ankle conditions. Specimens, consisting of the distal half of the tibia and fibula and the intact ankle and foot, were mounted in a materials testing system on a loading frame that allowed positioning in neutral, and 20 degrees of plantarflexion and dorsiflexion. An 800 N load (1 body weight) was axially applied to the specimens through the tibia with 10% of the total load distributed through the fibula. Transducers made of pressure-sensitive film were used to make a contact print and were scanned along with calibration strips to form a digital image. The image was analyzed quantitatively to determine total contact area, mean contact pressure, ratio of contact to plafond areas, and high pressure zone centroid location as a function of sagittal plane foot position in the normal ankle joint. The results demonstrated significant changes in ankle joint contact characteristics with different foot positions.

Anatomical variation of the tibial plafond: the anteromedial tibial notch.

An investigation of 77 intact foot and ankle specimens (21 fresh frozen and 62 preserved) was conducted to determine normal anatomical variation of the anteromedial region of the tibial plafond. Lower extremity specimens were obtained and carefully disarticulated at the ankle joint. Care was taken to observe anterior joint capsule attachments along with plafond surface anatomy. Specimens that exhibited signs of previous trauma or significant degenerative arthritic changes were not included in the study. All of the specimens were photographed with a millimeter scale, and the photographs were later evaluated to quantify anatomical variations of the anterior medial tibial plafond. The results of this investigation demonstrated a normal variant of articular notching of the anteromedial tibial plafond. The notching appears to function as a joint capsule anchor. In the more well developed notches, a fold, apparently of synovial tissue, was found. The notching increases the surface area for capsular attachment, is variable in size, and may assist in synovial fluid movement across the joint during ambulation. This articular notching, although often encountered arthroscopically, should be considered a normal anatomical variant unless localized degenerative processes are identified.

Lateral ankle stabilization using bovine collagen material: xenograft bioprosthesis, model GR.

This is a combined research study including use of a reproducible technique for ankle stress x-ray examinations (both preoperatively and postoperatively) and the use of the bovine bioprosthesis tendon implant for stabilization and augmentation of the lateral ankle ligaments. The surgical technique is fully described and the follow-up results indicate that there is long-term ankle stability, and that patient acceptance is very high.

Exposure time and frequency of irradiation in brain tumours.

The survival of a group of patients with malignant gliomas of the brain submitted to radical surgery and radiotherapy was studied. The average survival was nearly 4 times longer with X-ray treatment than with cobalt 60 irradiation when a comparison was made between 24 patients with glioblasto-astroblastoma (grade 3-4) who received one or the other type of treatment (12 patients in each group). These results are ascribed to the fact that the daily exposures to X-ray were much longer than with cobalt and so, during those prolonged sessions, a greater number of tumour cells could be destroyed as they successively reached the pre-mitotic period of enhanced vulnerability to radiation. A smaller group of patients irradiated with linear accelerators fared worse than those who received X-ray treatment. Changes to the parameters of irradiation used at the present time with cobalt units or linear accelerators are suggested.