Using Statistical Shape and Appearance Modelling to characterise the 3D shape and material properties of human lumbar vertebrae: A proof of concept study.

Patient variation affects the outcomes of a range of spinal interventions, from disc replacement to vertebral fixation and vertebroplasty. Statistical Shape and Appearance Modelling (SSAM) can be used to describe anatomical variation and pathological differences within the population. To better understand how bone density and shape variation affect load transfer with respect to surgical treatments, Finite Element (FE) models can be generated from a SSAM. The aim for this study is to understand whether geometric and density variation as well as multiple vertebral levels can be incorporated into a single SSAM and whether this can be used to investigate the relationships between, and effects of, the various modes of variation. FE models of 14 human lumbar vertebrae that had been µCT imaged and validated through experimental testing were used as input specimens for a SSAM. The validity of the SSAM was evaluated by using principal component analysis to identify the primary modes of geometric and bone density variation and comparing to those in the input set. FE models were generated from the SSAM to examine the response to loading. The mean error between the input set and generated models for volume, mean density and FE compressive stiffness were 10%, 3% and 10% respectively. Principal Component (PC) 1 captured the majority of the bone density variation. The remaining PCs described specific geometric variation. The FE models generated from the SSAM showed the variations in vertebral stiffness as a result of complex relationships between bone density and shape. The SSAM created has limited data for its input set, however, it acts as a proof of concept for the novel combination of material and shape variation into a single shape model. This approach and the tools developed can be applied to wider patient groups and treatment scenarios to improve patient stratification and to optimise treatments.

Idiopathic scoliosis and pineal lesions in Australian children.

PURPOSE: To determine whether treatment of pineal lesions in children is associated with development of idiopathic scoliosis. METHODS: 38 boys and 10 girls with pineal lesions were identified. Their mean age at presentation was 10 years. The pineal pathology varied from cysts and epidermoid to teratoma, germinoma, pineocytoma, and glioblastoma. Treatment ranged from biopsy/extirpation to radiotherapy. RESULTS: 12 patients died. No scoliosis was found in any females or any of the deceased. Two boys had scoliosis: one had a 12-degree right upper thoracic curve with 32-degree kyphosis and the other had a 60-degree right thoracolumbar idiopathic curve, requiring a 2-stage arthrodesis. CONCLUSION: Pineal ablation is not related to the development of idiopathic scoliosis in humans.

Characterization of phagolysosomal simulant fluid for study of beryllium aerosol particle dissolution.

A simulant of phagolysosomal fluid is needed for beryllium particle dissolution research because intraphagolysosomal dissolution is believed to be a necessary step in the cellular immune response associated with development of chronic beryllium disease. Thus, we refined and characterized a potassium hydrogen phthalate (KHP) buffered solution with pH 4.55, termed phagolysosomal simulant fluid (PSF), for use in a static dissolution technique. To characterize the simulant, beryllium dissolution in PSF was compared to dissolution in the J774A.1 murine cell line. The effects of ionic composition, buffer strength, and the presence of the antifungal agent alkylbenzyldimethylammonium chloride (ABDC) on beryllium dissolution in PSF were evaluated. Beryllium dissolution in PSF was not different from dissolution in the J774A.1 murine cell line (p = 0.78) or from dissolution in another simulant having the same pH but different ionic composition (p = 0.73). A buffer concentration of 0.01-M KHP did not appear adequate to maintain pH under all conditions. There was no difference between dissolution in PSF with 0.01-M KHP and 0.02-M KHP (p = 0.12). At 0.04-M KHP, beryllium dissolution was increased relative to 0.02-M KHP (p = 0.02). Use of a 0.02-M KHP buffer concentration in the standard formulation for PSF provided stability in pH without alteration of the dissolution rate. The presence of ABDC did not influence beryllium dissolution in PSF (p = 0.35). PSF appears to be a useful and appropriate model of in vitro beryllium dissolution when using a static dissolution technique. In addition, the critical approach used to evaluate and adjust the composition of PSF may serve as a framework for characterizing PSF to study dissolution of other metal and oxide particles.

Operative treatment of ankle fractures: a minimum ten-year follow-up.

The long-term outcome of 25 patients with bimalleolar fractures of the ankle was assessed ten to fourteen years following their fractures using the Phillips scoring system. All patients had undergone open reduction and anatomical internal fixation (as described in their operative notes in the medical records). 52% of patients had a good or excellent overall outcome while 24% had a poor overall outcome. This study has the longest follow-up period (10 to 14 years) to date on the outcomes of internal fixation of bimalleolar ankle fractures and demonstrates a higher percentage of poorer outcomes than has been previously described. This trend appears to be predictable as other studies with shorter term follow-up have already established a trend of increasing radiological evidence of post-traumatic arthritis with successively longer-term outcome reports.

Surgical outcomes of a randomized prospective trial involving patients with a proximal femoral fracture.

BACKGROUND: An orthopaedic management/patient-focused care unit (OMPFCU) involving a dedicated orthopaedic-geriatrics liaison team was established at the Royal Brisbane Hospital in 1994 in an effort to safely accelerate rehabilitation of patients with proximal femoral fractures. METHODS: The surgical outcomes of the patients were monitored in order to determine whether accelerated rehabilitation had any significant adverse effects on the surgical outcomes, measured by mortality, readmission to hospital, deep wound infection, fracture union delay, mobility and the revision surgery rate. RESULTS: No significant difference was recorded in mortality and morbidity, deep wound infection and revision surgery rates between patients in the Royal Brisbane Hospital OMPFCU and those in standard care in the orthopaedic surgery wards. CONCLUSION: Accelerated rehabilitation for patients with a proximal femoral fracture in a major teaching hospital can be accomplished safely.

Sample size-based indication of normality in lognormally distributed populations.

Occupational and environmental hygiene sampling strategies are usually dictated by factors that limit sample sizes to relatively small numbers. Often, parameters estimated from small sample sizes are then used to make further estimates of the occurrence of extreme events, which are governed by the underlying exposure distribution. We investigated the limitations superimposed by the number of samples in distinguishing an asymmetric (Lognormal) distribution through the rejection of a hypothesized symmetric (Normal) distribution. Sets of 5 to 250 synthetic samples from underlying Lognormal distributions with unit median were generated for 24 separate geometric standard deviations (GSDs), ranging from 1.25 to 7.00. Each simulated combination was repeated in blocks of 200 and each block was repeated tenfold. The synthetic samples were then tested for goodness of fit for Normality by using the Shapiro and Wilk's W Test. Results indicated that the number of samples required to distinguish between Normal and Lognormal distributions was inversely related to GSD. When GSD = 1.25, 169 samples were required for 90 percent distinction at alpha = 0.05. The criteria for success for GSD of 2.00 and 4.00 were 25 and 15 samples, respectively. These results led to the conclusion that the general inability to distinguish an underlying distribution may impose serious difficulties in the estimation of extreme events associated with occupational and environmental hygiene-related sampling.

The management of elderly patients with femoral fractures. A randomised controlled trial of early intervention versus standard care.

OBJECTIVE: To determine the effect of an early intervention program in an acute care setting on the length of stay in hospital of elderly patients with proximal femoral fractures. SETTING: Acute orthopaedic ward of a large teaching hospital. DESIGN AND PARTICIPANTS: A randomised controlled trial comparing 38 Intervention patients with 33 Standard Care patients. INTERVENTION: Early surgery, minimal narcotic analgesia, intense daily therapy and close monitoring of patient needs via a multidisciplinary approach versus routine hospital management. MAIN OUTCOME MEASURES: Length of stay (LOS); deaths; level of independent functioning. RESULTS: Mean LOS was shorter in the Intervention group than in the Standard Care group (21 days v. 32.5 days; P < 0.01). After adjusting for other factors that could affect LOS (eg, age, sex, pre-trauma functional levels, pre-trauma comorbidity and postsurgical complications), the Intervention program was significantly predictive of shorter LOS (P = 0.01). The Intervention group did not experience greater numbers of deaths, deterioration in function or need for social support than the Standard Care group. CONCLUSION: This early intervention program in an acute care setting results in significantly shorter length of hospital stay for elderly patients with femoral fractures.

Outcomes following treatment of metastatic spine tumors.

Fifty seven consecutive patients with metastatic spine tumors were assessed for their suitability for operative treatment or radiotherapy and/or chemotherapy using a modified version of the Nihon University scoring system. Using this scoring system 29 patients underwent surgery and 28 received radiotherapy/chemotherapy. The outcomes were assessed to determine if a modified scoring had any effect on patient survival. No statistical difference was found between the two groups, though a trend was noted--the group receiving surgery had a mean survival of 30 weeks compared to a mean survival of 16 weeks found in the non-surgical group.

Pulmonary functions in congenital scoliosis.

STUDY DESIGN: Thirty-six patients with congenital scoliosis underwent full clinical and radiologic evaluation of their deformity and their full pulmonary functions. OBJECTIVES: This study observed pulmonary functions in congenital scoliosis in detail, evaluated pulmonary functions in nonsurgically treated patients, and established whether, in surgically treated patients, there are any differences between those with multiple thoracic anomalies and those with lumbar or one of two thoracic anomalies. SUMMARY OF BACKGROUND DATA: Eighty-six of our patients in both groups (surgically and nonsurgically treated) showed abnormal increases in residual volumes, indicating a restrictive pattern of lung function. The results of their pulmonary functions were analyzed using predicted values to eliminate age affect. METHODS: Pulmonary functions were assessed using the Gould 5000IV Computerized Pulmonary Function System. RESULTS: Overall, mean total lung capacity was 89% of predicted value, and mean vital capacity and forced vital capacity were 74% of predicted value. The mean residual volume was significantly increased, being 154% of predicted value. Nonsurgically treated patients showed normal total lung capacity (mean 99.8% of predicted value); this mean value was 82% of predicted value in surgically treated patients. CONCLUSION: Vital capacity was found to be significantly reduced in surgically treated patients (68% of predicted value), especially in those patients who had multiple thoracic anomalies. We believe that children with congenital scoliosis due to multiple anomalies should be operated on at an early age before deformity is too severe.

Nine-year mean follow-up of one-stage anteroposterior excision of hemivertebrae in the lumbosacral spine.

Six patients with lumbosacral hemivertebrae were treated by one-stage anterior and posterior excision of the hemivertebrae. Long-term follow-up is reported. Overall, correction of the lumbosacral curve was 46%, including one case of pseudarthrosis and subsequent loss of correction. More importantly, truncal imbalance was restored unless other congenital thoracic anomalies were present. New methods of calculating rib cage shift on the pelvis as well as vertebral column displacement from the sagittal plane are presented.

Restrictive pattern of pulmonary functions in idiopathic and congenital scoliosis following spinal fusion.

This paper presents the results of pulmonary function analysis in 141 subjects. Thirty-five of these were patients with adolescent idiopathic scoliosis, 36 had congenital scoliosis, and the remaining 70 were age-, sex-, height-, weight- and arm-span-matched normal subjects used as controls for adolescent idiopathic scoliosis. The patients with adolescent idiopathic scoliosis had their pulmonary function evaluated pre- and post-operatively. At pre-operative evaluation the mean age was 13.7 years and the mean cobb angle 48 degrees; at post-operative evaluation the figures were 17.1 years and 36 degrees respectively. In the congenital scoliosis group the mean age was 14.5 years and the mean Cobb angle 42 degrees, and pulmonary functions were evaluated at a minimum of 3 years after surgery. The results are as follows: Adolescent idiopathic scoliosis: (i) Marked disproportion was found in the pulmonary volumes following spinal surgery. After taking growth of the thoracic cage into account, the total lung capacity remained unchanged whilst the vital capacity was significantly reduced and there was a significant increase in residual volume. (ii) This disproportionate increase in residual volume was further confirmed by very highly significantly increased residual volume/vital capacity and residual volume/total lung capacity ratios at post-operative evaluation compared to pre-operative ratios (Mann-Whitney test, P = 0.001). (iii) The residual volume was 48% of vital capacity preoperatively compared to 35% in normal controls. The percentages increased to 70% post-operatively, whilst it was unchanged in the matched controls. Congenital scoliosis: (i) The mean residual volume was markedly increased (154% of predicted value). (ii) Vital capacity was significantly reduced in surgically treated patients (68% of predicted values). (iii) This pattern of reduced vital capacity was more marked in those patients who had multiple thoracic anomalies and were treated surgically (46% of predicted value). However, those patients with multiple thoracic anomalies who did not require surgery did not show such reduction of vital capacity. Comparison between idiopathic and congenital scoliosis: (i) In unoperated patients, the percentages of predicted values of total lung capacity, vital capacity and residual volume were significantly greater in congenital scoliosis than in adolescent idiopathic scoliosis. (ii) Post-operatively there was no significant difference in the percentages of predicted values of total lung capacity, vital capacity and residual volume between patients with congenital scoliosis and those with adolescent idiopathic scoliosis, despite the difference in pathogenesis. These findings have relevance to scoliotic patients treated with spinal fusion with regard to their capability to perform strenuous physical activities.

Open-cavity mastoid surgery: its effect on the acoustics of the external ear canal.

Temporal bone studies have demonstrated that a modified radical mastoidectomy changes the resonant characteristics of the external auditory canal, but the effect has not been reported in patients. In 12 patients, performing open-cavity mastoid surgery for cholesteatoma changed the mean peak resonant frequency of the external ear canal from 2.5 to 2.2 kHz (p less than 0.02). This is in comparison with creating a modified radical mastoid cavity in 6 temporal bones which changed the mean peak resonant frequency of the external ear canal from 3.9 to 1.9 kHz. It is concluded that open-cavity mastoid surgery in patients changes the acoustics of the external ear canal less than in temporal bone studies.

Benefit from binaural hearing aids in individuals with a severe hearing impairment.

The relative benefits of binaural as opposed to monaural hearing aids were assessed by the use of a diotically presented, audiovisual speech-in-noise task in a group of bilateral, severely hearing-impaired individuals. Significantly greater benefit was gained from binaural amplification, irrespective of hearing level and degree of asymmetry. The benefit was considered to be due to central summation. It is concluded that binaural amplification should be attempted in all bilateral, severely hearing-impaired subjects. About 80% will accept this and be able to demonstrate benefit in an audiovisual task.

An audiovisual test of hearing disability using free-field sentences in noise.

An audiovisual test, using BKB sentences in noise, has been developed to assess hearing disability, unaided and aided with a hearing aid(s), in severely hearing-impaired individuals. After a single practice list, no significant further increases in performance were detected. The test is reproducible within and between test sessions.

Biomechanical Analysis of Patient Using FES Peroneal Brace and Further Developments.

The effect of functional electrical stimulation on gait and postural sway of hemiplegics was studied. Patients utilizing the Underknee Peroneal Stimulator were studied and compared to patients receiving conventional physiotherapy and to normal subjects. Several patients treated with electrical stimulation showed marked improvement in postural sway and ankle control during locomotion. Additional studies on the effect of various stimulation waveforms and pain sensation in a computer-controlled double blind evaluation are discussed.